[PATCH] D68720: Support -fstack-clash-protection for x86

[serge via Phabricator via cfe-commits]

serge-sans-paille added inline comments.



Comment at: clang/lib/Driver/ToolChains/Clang.cpp:3009-3010
+
+  if (!EffectiveTriple.isOSLinux())
+return;
+

emaste wrote:
> Is there anything OS-dependent here?
> 
> I plan to add `EffectiveTriple.isOSFreeBSD()` to FreeBSD-s in-tree Clang
> https://reviews.freebsd.org/D27366
> and intend to upstream the change (with a test), but should we just remove 
> the OS test completely?
According to 
https://blog.qualys.com/vulnerabilities-research/2017/06/19/the-stack-clash, 
stack clash impacts

> Linux, OpenBSD, NetBSD, FreeBSD and Solaris

We should probably enlarge the test to these platforms. 


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[PATCH] D68720: Support -fstack-clash-protection for x86

[Ed Maste via Phabricator via cfe-commits]

emaste added inline comments.
Herald added subscribers: dexonsmith, pengfei.



Comment at: clang/lib/Driver/ToolChains/Clang.cpp:3009-3010
+
+  if (!EffectiveTriple.isOSLinux())
+return;
+

Is there anything OS-dependent here?

I plan to add `EffectiveTriple.isOSFreeBSD()` to FreeBSD-s in-tree Clang
https://reviews.freebsd.org/D27366
and intend to upstream the change (with a test), but should we just remove the 
OS test completely?


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[PATCH] D68720: Support -fstack-clash-protection for x86

[Kees Cook via Phabricator via cfe-commits]

kees added a comment.

Ah! Yes, I see it now. Thanks and sorry for the noise!


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[PATCH] D68720: Support -fstack-clash-protection for x86

[Eli Friedman via Phabricator via cfe-commits]

efriedma closed this revision.
efriedma added a comment.

It was reverted, then re-landed.  It's in trunk now.


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[PATCH] D68720: Support -fstack-clash-protection for x86

[Kees Cook via Phabricator via cfe-commits]

kees reopened this revision.
kees added a comment.
This revision is now accepted and ready to land.

Sorry if I missed something here, but why is this marked as "Closed"? It seems 
like the feature has still not landed (i.e. it got reverted).


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[PATCH] D68720: Support -fstack-clash-protection for x86

[Stephan Bergmann via Phabricator via cfe-commits]

sberg added a comment.

I filed https://bugs.llvm.org/show_bug.cgi?id=47139 "Misspelled 
-fnostack-clash-protection" now.


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[PATCH] D68720: Support -fstack-clash-protection for x86

[Dávid Bolvanský via Phabricator via cfe-commits]

xbolva00 added inline comments.



Comment at: clang/include/clang/Driver/Options.td:1778
+  HelpText<"Enable stack clash protection">;
+def fnostack_clash_protection : Flag<["-"], "fnostack-clash-protection">, 
Group,
+  HelpText<"Disable stack clash protection">;

sberg wrote:
> Should this rather spell `"fno-stack-clash-protection"`?  The above change to 
> clang/docs/ClangCommandLineReference.rst (but which got overwritten by 
> 
>  "[docs] Regenerate ClangCommandLineReference.rst") mentions 
> `-fno-stack-clash-protection`, and also GCC calls it like that.  (Though the 
> below clang/test/Driver/stack-clash-protection.c does use 
> `-fnostack-clash-protection`.)
And the fix should be backported to release branch.

@hans


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[PATCH] D68720: Support -fstack-clash-protection for x86

[Stephan Bergmann via Phabricator via cfe-commits]

sberg added inline comments.
Herald added a subscriber: dang.



Comment at: clang/include/clang/Driver/Options.td:1778
+  HelpText<"Enable stack clash protection">;
+def fnostack_clash_protection : Flag<["-"], "fnostack-clash-protection">, 
Group,
+  HelpText<"Disable stack clash protection">;

Should this rather spell `"fno-stack-clash-protection"`?  The above change to 
clang/docs/ClangCommandLineReference.rst (but which got overwritten by 

 "[docs] Regenerate ClangCommandLineReference.rst") mentions 
`-fno-stack-clash-protection`, and also GCC calls it like that.  (Though the 
below clang/test/Driver/stack-clash-protection.c does use 
`-fnostack-clash-protection`.)


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[PATCH] D68720: Support -fstack-clash-protection for x86

[serge via Phabricator via cfe-commits]

serge-sans-paille added a comment.

For the record: tests have been updated, option handling cleaned up and 
expansive check failure fixed in commit 
e67cbac81211d40332a79d98c9d5953624cc1202 
.


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Re: [PATCH] D68720: Support -fstack-clash-protection for x86

[Serge Guelton via cfe-commits]

On Sat, Feb 08, 2020 at 01:26:03PM +, Simon Pilgrim via Phabricator wrote:
> RKSimon added a comment.
> 
> @serge-sans-paille Please can you fix the issues with EXPENSIVE_CHECKS 
> builds: 
> http://lab.llvm.org:8011/builders/llvm-clang-x86_64-expensive-checks-debian/builds/2604

yeah, spotted that... and reverted

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[PATCH] D68720: Support -fstack-clash-protection for x86

[Simon Pilgrim via Phabricator via cfe-commits]

RKSimon added a comment.

@serge-sans-paille Please can you fix the issues with EXPENSIVE_CHECKS builds: 
http://lab.llvm.org:8011/builders/llvm-clang-x86_64-expensive-checks-debian/builds/2604


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Re: [PATCH] D68720: Support -fstack-clash-protection for x86

[Serge Guelton via cfe-commits]

On Fri, Feb 07, 2020 at 07:12:39PM +, Nico Weber via Phabricator wrote:
> thakis added a comment.
> 
> This breaks check-clang on mac and win: 
> http://45.33.8.238/mac/7485/step_7.txt http://45.33.8.238/win/7753/step_7.txt
> 
> Please revert and then investigate asynchronously, unless the fix is obvious.
> 
> 
> 
> 
> Comment at: clang/test/CodeGen/stack-clash-protection.c:2
> +// check interaction between -fstack-clash-protection and dynamic allocation 
> schemes
> +// RUN: %clang -target x86_64 -O0 -o %t.out %s -fstack-clash-protection && 
> %t.out
> +
> 
> Tests should compile binaries and then run them if at all possible. This is 
> impossible in cross-build scenarios and in general we try hard to have unit 
> tests, not integration tests. Check that this produces the IR you expect, and 
> have an llvm-level test that the IR produces the assembly you expect, and if 
> you must, an lld level test that checks that the generated elf file looks 
> like you think.

ok, thanks for the hint! Indeed I overlooked the cross compilation situation.
Thanks for the hint and for reverting!
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[PATCH] D68720: Support -fstack-clash-protection for x86

[Vlad Vereschaka via Phabricator via cfe-commits]

vvereschaka added a comment.

Also got failed clang tests on Arm/Aarch64 builders

http://lab.llvm.org:8011/builders/llvm-clang-win-x-armv7l/builds/4295
http://lab.llvm.org:8011/builders/llvm-clang-win-x-aarch64/builds/4277

- FAIL: Clang::stack-clash-protection.c
- FAIL: Clang::stack-clash-protection.c

  error: unable to create target: 'No available targets are compatible with 
triple "x86_64"'

looks like `REQUIRES: x86-registered-target` keyword is needed.


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[PATCH] D68720: Support -fstack-clash-protection for x86

[Nico Weber via Phabricator via cfe-commits]

thakis added a comment.

Reverted in b03c3d8c620 
 for now.


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[PATCH] D68720: Support -fstack-clash-protection for x86

[Nico Weber via Phabricator via cfe-commits]

thakis added a comment.

This breaks check-clang on mac and win: http://45.33.8.238/mac/7485/step_7.txt 
http://45.33.8.238/win/7753/step_7.txt

Please revert and then investigate asynchronously, unless the fix is obvious.




Comment at: clang/test/CodeGen/stack-clash-protection.c:2
+// check interaction between -fstack-clash-protection and dynamic allocation 
schemes
+// RUN: %clang -target x86_64 -O0 -o %t.out %s -fstack-clash-protection && 
%t.out
+

Tests should compile binaries and then run them if at all possible. This is 
impossible in cross-build scenarios and in general we try hard to have unit 
tests, not integration tests. Check that this produces the IR you expect, and 
have an llvm-level test that the IR produces the assembly you expect, and if 
you must, an lld level test that checks that the generated elf file looks like 
you think.


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[PATCH] D68720: Support -fstack-clash-protection for x86

[Hans Wennborg via Phabricator via cfe-commits]

hans added a comment.

This seems to be breaking the buildbots, e.g.
http://lab.llvm.org:8011/builders/clang-cmake-x86_64-sde-avx512-linux/builds/33475/steps/ninja%20check%201/logs/FAIL%3A%20Clang%3A%3Astack-clash-protection.c
http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-ubuntu-fast/builds/62154/steps/test-check-all/logs/stdio
http://45.33.8.238/win/7706/step_7.txt


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[PATCH] D68720: Support -fstack-clash-protection for x86

[serge via Phabricator via cfe-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rG39f50da2a357: Support -fstack-clash-protection for x86 
(authored by serge-sans-paille).

Changed prior to commit:
  https://reviews.llvm.org/D68720?vs=240844=243101#toc

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Files:
  clang/docs/ClangCommandLineReference.rst
  clang/docs/ReleaseNotes.rst
  clang/include/clang/Basic/CodeGenOptions.def
  clang/include/clang/Basic/DiagnosticCommonKinds.td
  clang/include/clang/Basic/TargetInfo.h
  clang/include/clang/Driver/CC1Options.td
  clang/include/clang/Driver/Options.td
  clang/lib/Basic/Targets/X86.h
  clang/lib/CodeGen/CGStmt.cpp
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/test/CodeGen/stack-clash-protection.c
  clang/test/Driver/stack-clash-protection.c
  llvm/docs/ReleaseNotes.rst
  llvm/include/llvm/CodeGen/TargetLowering.h
  llvm/lib/Target/X86/X86CallFrameOptimization.cpp
  llvm/lib/Target/X86/X86FrameLowering.cpp
  llvm/lib/Target/X86/X86FrameLowering.h
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/lib/Target/X86/X86ISelLowering.h
  llvm/lib/Target/X86/X86InstrCompiler.td
  llvm/lib/Target/X86/X86InstrInfo.td
  llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
  llvm/test/CodeGen/X86/stack-clash-large.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes-mutliple-objects.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
  llvm/test/CodeGen/X86/stack-clash-medium.ll
  llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
  llvm/test/CodeGen/X86/stack-clash-small.ll
  llvm/test/CodeGen/X86/stack-clash-unknown-call.ll

Index: llvm/test/CodeGen/X86/stack-clash-unknown-call.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-unknown-call.ll
@@ -0,0 +1,31 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+declare void @llvm.memset.p0i8.i64(i8* nocapture writeonly, i8, i64, i1 immarg);
+
+define void @foo() local_unnamed_addr #0 {
+
+;CHECK-LABEL: foo:
+;CHECK: # %bb.0:
+;CHECK-NEXT:	subq	$4096, %rsp # imm = 0x1000
+; it's important that we don't use the call as a probe here
+;CHECK-NEXT:	movq	$0, (%rsp)
+;CHECK-NEXT:	subq	$3912, %rsp # imm = 0xF48
+;CHECK-NEXT:	.cfi_def_cfa_offset 8016
+;CHECK-NEXT:	movq	%rsp, %rdi
+;CHECK-NEXT:	movl	$8000, %edx # imm = 0x1F40
+;CHECK-NEXT:	xorl	%esi, %esi
+;CHECK-NEXT:	callq	memset
+;CHECK-NEXT:	addq	$8008, %rsp # imm = 0x1F48
+;CHECK-NEXT:	.cfi_def_cfa_offset 8
+;CHECK-NEXT:	retq
+
+  %a = alloca i8, i64 8000, align 16
+  call void @llvm.memset.p0i8.i64(i8* align 16 %a, i8 0, i64 8000, i1 false)
+  ret void
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-small.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-small.ll
@@ -0,0 +1,25 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo() local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 288
+; CHECK-NEXT:  movl	$1, 264(%rsp)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i64 100, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 98
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
@@ -0,0 +1,27 @@
+; RUN: llc < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo(i64 %i) local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$4096, %rsp # imm = 0x1000
+; CHECK-NEXT:  movq	$0, (%rsp)
+; CHECK-NEXT:  subq	$3784, %rsp # imm = 0xEC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 7888
+; CHECK-NEXT:  movl	$1, -128(%rsp,%rdi,4)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$7880, %rsp # imm = 0x1EC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i32 2000, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 %i
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
+
Index: llvm/test/CodeGen/X86/stack-clash-medium.ll

[PATCH] D68720: Support -fstack-clash-protection for x86

[serge via Phabricator via cfe-commits]

serge-sans-paille added a subscriber: hans.
serge-sans-paille added a comment.

I would love too, @hans what do you think?


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[PATCH] D68720: Support -fstack-clash-protection for x86

[Sylvestre Ledru via Phabricator via cfe-commits]

sylvestre.ledru added a comment.

In D68720#1862050 , @xbolva00 wrote:

> Any plans to merge this feature to 10 release?


I would love to have it in -10 for Firefox !


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[PATCH] D68720: Support -fstack-clash-protection for x86

[Dávid Bolvanský via Phabricator via cfe-commits]

xbolva00 added a comment.

Any plans to merge this feature to 10 release?


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[PATCH] D68720: Support -fstack-clash-protection for x86

[Craig Topper via Phabricator via cfe-commits]

craig.topper accepted this revision.
craig.topper added a comment.
This revision is now accepted and ready to land.

LGTM


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[PATCH] D68720: Support -fstack-clash-protection for x86

[serge via Phabricator via cfe-commits]

serge-sans-paille added a comment.

@craig.topper up :-)


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[PATCH] D68720: Support -fstack-clash-protection for x86

[pre-merge checks [bot] via Phabricator via cfe-commits]

merge_guards_bot added a comment.

{icon check-circle color=green} Unit tests: pass. 62269 tests passed, 0 failed 
and 827 were skipped.

{icon times-circle color=red} clang-tidy: fail. clang-tidy found 0 errors and 
16 warnings 
.
 0 of them are added as review comments below (why? 
).

{icon times-circle color=red} clang-format: fail. Please format your changes 
with clang-format by running `git-clang-format HEAD^` or applying this patch 
.

Build artifacts 
: 
diff.json 
,
 clang-tidy.txt 
,
 clang-format.patch 
,
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,
 console-log.txt 
,
 test-results.xml 


//Pre-merge checks is in beta. Report issue 
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[PATCH] D68720: Support -fstack-clash-protection for x86

[serge via Phabricator via cfe-commits]

serge-sans-paille updated this revision to Diff 240844.
serge-sans-paille added a comment.

Make some tests more portable.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D68720/new/

https://reviews.llvm.org/D68720

Files:
  clang/docs/ClangCommandLineReference.rst
  clang/docs/ReleaseNotes.rst
  clang/include/clang/Basic/CodeGenOptions.def
  clang/include/clang/Basic/DiagnosticCommonKinds.td
  clang/include/clang/Basic/TargetInfo.h
  clang/include/clang/Driver/CC1Options.td
  clang/include/clang/Driver/Options.td
  clang/lib/Basic/Targets/X86.h
  clang/lib/CodeGen/CGStmt.cpp
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/test/CodeGen/stack-clash-protection.c
  clang/test/Driver/stack-clash-protection.c
  llvm/docs/ReleaseNotes.rst
  llvm/include/llvm/CodeGen/TargetLowering.h
  llvm/lib/Target/X86/X86CallFrameOptimization.cpp
  llvm/lib/Target/X86/X86FrameLowering.cpp
  llvm/lib/Target/X86/X86FrameLowering.h
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/lib/Target/X86/X86ISelLowering.h
  llvm/lib/Target/X86/X86InstrCompiler.td
  llvm/lib/Target/X86/X86InstrInfo.td
  llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
  llvm/test/CodeGen/X86/stack-clash-large.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes-mutliple-objects.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
  llvm/test/CodeGen/X86/stack-clash-medium.ll
  llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
  llvm/test/CodeGen/X86/stack-clash-small.ll
  llvm/test/CodeGen/X86/stack-clash-unknown-call.ll

Index: llvm/test/CodeGen/X86/stack-clash-unknown-call.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-unknown-call.ll
@@ -0,0 +1,31 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+declare void @llvm.memset.p0i8.i64(i8* nocapture writeonly, i8, i64, i1 immarg);
+
+define void @foo() local_unnamed_addr #0 {
+
+;CHECK-LABEL: foo:
+;CHECK: # %bb.0:
+;CHECK-NEXT:	subq	$4096, %rsp # imm = 0x1000
+; it's important that we don't use the call as a probe here
+;CHECK-NEXT:	movq	$0, (%rsp)
+;CHECK-NEXT:	subq	$3912, %rsp # imm = 0xF48
+;CHECK-NEXT:	.cfi_def_cfa_offset 8016
+;CHECK-NEXT:	movq	%rsp, %rdi
+;CHECK-NEXT:	movl	$8000, %edx # imm = 0x1F40
+;CHECK-NEXT:	xorl	%esi, %esi
+;CHECK-NEXT:	callq	memset
+;CHECK-NEXT:	addq	$8008, %rsp # imm = 0x1F48
+;CHECK-NEXT:	.cfi_def_cfa_offset 8
+;CHECK-NEXT:	retq
+
+  %a = alloca i8, i64 8000, align 16
+  call void @llvm.memset.p0i8.i64(i8* align 16 %a, i8 0, i64 8000, i1 false)
+  ret void
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-small.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-small.ll
@@ -0,0 +1,25 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo() local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 288
+; CHECK-NEXT:  movl	$1, 264(%rsp)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i64 100, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 98
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
@@ -0,0 +1,27 @@
+; RUN: llc < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo(i64 %i) local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$4096, %rsp # imm = 0x1000
+; CHECK-NEXT:  movq	$0, (%rsp)
+; CHECK-NEXT:  subq	$3784, %rsp # imm = 0xEC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 7888
+; CHECK-NEXT:  movl	$1, -128(%rsp,%rdi,4)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$7880, %rsp # imm = 0x1EC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i32 2000, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 %i
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
+
Index: llvm/test/CodeGen/X86/stack-clash-medium.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-medium.ll
@@ -0,0 +1,30 @@
+; RUN: llc < %s | FileCheck %s
+

[PATCH] D68720: Support -fstack-clash-protection for x86

[pre-merge checks [bot] via Phabricator via cfe-commits]

merge_guards_bot added a comment.

{icon times-circle color=red} Unit tests: fail. 62059 tests passed, 1 failed 
and 783 were skipped.

  failed: Clang.CodeGen/stack-clash-protection.c

{icon question-circle color=gray} clang-tidy: unknown.

{icon times-circle color=red} clang-format: fail. Please format your changes 
with clang-format by running `git-clang-format HEAD^` or applying this patch 
.

Build artifacts 
: 
diff.json 
,
 clang-format.patch 
,
 CMakeCache.txt 
,
 console-log.txt 
,
 test-results.xml 



Repository:
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[PATCH] D68720: Support -fstack-clash-protection for x86

[serge via Phabricator via cfe-commits]

serge-sans-paille updated this revision to Diff 239257.
serge-sans-paille added a comment.

Update warning category


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D68720/new/

https://reviews.llvm.org/D68720

Files:
  clang/docs/ClangCommandLineReference.rst
  clang/docs/ReleaseNotes.rst
  clang/include/clang/Basic/CodeGenOptions.def
  clang/include/clang/Basic/DiagnosticCommonKinds.td
  clang/include/clang/Basic/TargetInfo.h
  clang/include/clang/Driver/CC1Options.td
  clang/include/clang/Driver/Options.td
  clang/lib/Basic/Targets/X86.h
  clang/lib/CodeGen/CGStmt.cpp
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/test/CodeGen/stack-clash-protection.c
  clang/test/Driver/stack-clash-protection.c
  llvm/docs/ReleaseNotes.rst
  llvm/include/llvm/CodeGen/TargetLowering.h
  llvm/lib/Target/X86/X86CallFrameOptimization.cpp
  llvm/lib/Target/X86/X86FrameLowering.cpp
  llvm/lib/Target/X86/X86FrameLowering.h
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/lib/Target/X86/X86ISelLowering.h
  llvm/lib/Target/X86/X86InstrCompiler.td
  llvm/lib/Target/X86/X86InstrInfo.td
  llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
  llvm/test/CodeGen/X86/stack-clash-large.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes-mutliple-objects.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
  llvm/test/CodeGen/X86/stack-clash-medium.ll
  llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
  llvm/test/CodeGen/X86/stack-clash-small.ll
  llvm/test/CodeGen/X86/stack-clash-unknown-call.ll

Index: llvm/test/CodeGen/X86/stack-clash-unknown-call.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-unknown-call.ll
@@ -0,0 +1,31 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+declare void @llvm.memset.p0i8.i64(i8* nocapture writeonly, i8, i64, i1 immarg);
+
+define void @foo() local_unnamed_addr #0 {
+
+;CHECK-LABEL: foo:
+;CHECK: # %bb.0:
+;CHECK-NEXT:	subq	$4096, %rsp # imm = 0x1000
+; it's important that we don't use the call as a probe here
+;CHECK-NEXT:	movq	$0, (%rsp)
+;CHECK-NEXT:	subq	$3912, %rsp # imm = 0xF48
+;CHECK-NEXT:	.cfi_def_cfa_offset 8016
+;CHECK-NEXT:	movq	%rsp, %rdi
+;CHECK-NEXT:	movl	$8000, %edx # imm = 0x1F40
+;CHECK-NEXT:	xorl	%esi, %esi
+;CHECK-NEXT:	callq	memset
+;CHECK-NEXT:	addq	$8008, %rsp # imm = 0x1F48
+;CHECK-NEXT:	.cfi_def_cfa_offset 8
+;CHECK-NEXT:	retq
+
+  %a = alloca i8, i64 8000, align 16
+  call void @llvm.memset.p0i8.i64(i8* align 16 %a, i8 0, i64 8000, i1 false)
+  ret void
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-small.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-small.ll
@@ -0,0 +1,25 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo() local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 288
+; CHECK-NEXT:  movl	$1, 264(%rsp)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i64 100, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 98
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
@@ -0,0 +1,27 @@
+; RUN: llc < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo(i64 %i) local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$4096, %rsp # imm = 0x1000
+; CHECK-NEXT:  movq	$0, (%rsp)
+; CHECK-NEXT:  subq	$3784, %rsp # imm = 0xEC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 7888
+; CHECK-NEXT:  movl	$1, -128(%rsp,%rdi,4)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$7880, %rsp # imm = 0x1EC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i32 2000, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 %i
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
+
Index: llvm/test/CodeGen/X86/stack-clash-medium.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-medium.ll
@@ -0,0 +1,30 @@
+; RUN: llc < %s | FileCheck %s
+
+

[PATCH] D68720: Support -fstack-clash-protection for x86

[pre-merge checks [bot] via Phabricator via cfe-commits]

merge_guards_bot added a comment.

{icon times-circle color=red} Unit tests: fail. 62035 tests passed, 2 failed 
and 783 were skipped.

  failed: Clang.CodeGen/stack-clash-protection.c
  failed: Clang.Misc/warning-flags.c

{icon question-circle color=gray} clang-tidy: unknown.

{icon times-circle color=red} clang-format: fail. Please format your changes 
with clang-format by running `git-clang-format HEAD^` or applying this patch 
.

Build artifacts 
: 
diff.json 
,
 clang-format.patch 
,
 CMakeCache.txt 
,
 console-log.txt 
,
 test-results.xml 



Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D68720/new/

https://reviews.llvm.org/D68720



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[PATCH] D68720: Support -fstack-clash-protection for x86

[serge via Phabricator via cfe-commits]

serge-sans-paille updated this revision to Diff 239166.
serge-sans-paille added a comment.

- Harmonize esp/rsp usage as hinted by @craig.topper
- Fix argument detection


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D68720/new/

https://reviews.llvm.org/D68720

Files:
  clang/docs/ClangCommandLineReference.rst
  clang/docs/ReleaseNotes.rst
  clang/include/clang/Basic/CodeGenOptions.def
  clang/include/clang/Basic/DiagnosticCommonKinds.td
  clang/include/clang/Basic/TargetInfo.h
  clang/include/clang/Driver/CC1Options.td
  clang/include/clang/Driver/Options.td
  clang/lib/Basic/Targets/X86.h
  clang/lib/CodeGen/CGStmt.cpp
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/test/CodeGen/stack-clash-protection.c
  clang/test/Driver/stack-clash-protection.c
  llvm/docs/ReleaseNotes.rst
  llvm/include/llvm/CodeGen/TargetLowering.h
  llvm/lib/Target/X86/X86CallFrameOptimization.cpp
  llvm/lib/Target/X86/X86FrameLowering.cpp
  llvm/lib/Target/X86/X86FrameLowering.h
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/lib/Target/X86/X86ISelLowering.h
  llvm/lib/Target/X86/X86InstrCompiler.td
  llvm/lib/Target/X86/X86InstrInfo.td
  llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
  llvm/test/CodeGen/X86/stack-clash-large.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes-mutliple-objects.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
  llvm/test/CodeGen/X86/stack-clash-medium.ll
  llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
  llvm/test/CodeGen/X86/stack-clash-small.ll
  llvm/test/CodeGen/X86/stack-clash-unknown-call.ll

Index: llvm/test/CodeGen/X86/stack-clash-unknown-call.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-unknown-call.ll
@@ -0,0 +1,31 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+declare void @llvm.memset.p0i8.i64(i8* nocapture writeonly, i8, i64, i1 immarg);
+
+define void @foo() local_unnamed_addr #0 {
+
+;CHECK-LABEL: foo:
+;CHECK: # %bb.0:
+;CHECK-NEXT:	subq	$4096, %rsp # imm = 0x1000
+; it's important that we don't use the call as a probe here
+;CHECK-NEXT:	movq	$0, (%rsp)
+;CHECK-NEXT:	subq	$3912, %rsp # imm = 0xF48
+;CHECK-NEXT:	.cfi_def_cfa_offset 8016
+;CHECK-NEXT:	movq	%rsp, %rdi
+;CHECK-NEXT:	movl	$8000, %edx # imm = 0x1F40
+;CHECK-NEXT:	xorl	%esi, %esi
+;CHECK-NEXT:	callq	memset
+;CHECK-NEXT:	addq	$8008, %rsp # imm = 0x1F48
+;CHECK-NEXT:	.cfi_def_cfa_offset 8
+;CHECK-NEXT:	retq
+
+  %a = alloca i8, i64 8000, align 16
+  call void @llvm.memset.p0i8.i64(i8* align 16 %a, i8 0, i64 8000, i1 false)
+  ret void
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-small.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-small.ll
@@ -0,0 +1,25 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo() local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 288
+; CHECK-NEXT:  movl	$1, 264(%rsp)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i64 100, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 98
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
@@ -0,0 +1,27 @@
+; RUN: llc < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo(i64 %i) local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$4096, %rsp # imm = 0x1000
+; CHECK-NEXT:  movq	$0, (%rsp)
+; CHECK-NEXT:  subq	$3784, %rsp # imm = 0xEC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 7888
+; CHECK-NEXT:  movl	$1, -128(%rsp,%rdi,4)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$7880, %rsp # imm = 0x1EC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i32 2000, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 %i
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
+
Index: llvm/test/CodeGen/X86/stack-clash-medium.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-medium.ll
@@ 

[PATCH] D68720: Support -fstack-clash-protection for x86

[Craig Topper via Phabricator via cfe-commits]

craig.topper added inline comments.



Comment at: llvm/lib/Target/X86/X86ISelLowering.cpp:31080
+
+  BuildMI(blockMBB, DL, TII->get(IsLP64 ? X86::SUB64ri32 : X86::SUB32ri),
+  physSPReg)

serge-sans-paille wrote:
> craig.topper wrote:
> > This uses physSPReg, but doesn't match the condition for when physSPReg is 
> > a 64-bit register. Same at several places below.
> Sorry, I don't understand your remark. Can you elaborate?
If physSPReg is RSP then you need to use SUB64ri32 and if its ESP you need to 
use SUB32ri. The condition you're using here is "IsLP64", but the condition for 
phySPReg to be RSP is "IsLP64 || Subtarget.isTargetNaCl64()". So there's a 
mismatch when IsLP64 is false and Subtarget.isTargetNaCl64() is true.


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[PATCH] D68720: Support -fstack-clash-protection for x86

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{icon times-circle color=red} Unit tests: fail. 61960 tests passed, 3 failed 
and 783 were skipped.

  failed: Clang.CodeGen/stack-clash-protection.c
  failed: Clang.Driver/stack-clash-protection.c
  failed: Clang.Misc/warning-flags.c

{icon question-circle color=gray} clang-tidy: unknown.

{icon times-circle color=red} clang-format: fail. Please format your changes 
with clang-format by running `git-clang-format HEAD^` or applying this patch 
.

Build artifacts 
: 
diff.json 
,
 clang-format.patch 
,
 CMakeCache.txt 
,
 console-log.txt 
,
 test-results.xml 



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[PATCH] D68720: Support -fstack-clash-protection for x86

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serge-sans-paille updated this revision to Diff 238758.
serge-sans-paille marked 5 inline comments as done.
serge-sans-paille added a comment.

Take into account some of the reviews


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Files:
  clang/docs/ClangCommandLineReference.rst
  clang/docs/ReleaseNotes.rst
  clang/include/clang/Basic/CodeGenOptions.def
  clang/include/clang/Basic/DiagnosticCommonKinds.td
  clang/include/clang/Basic/TargetInfo.h
  clang/include/clang/Driver/CC1Options.td
  clang/include/clang/Driver/Options.td
  clang/lib/Basic/Targets/X86.h
  clang/lib/CodeGen/CGStmt.cpp
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/test/CodeGen/stack-clash-protection.c
  clang/test/Driver/stack-clash-protection.c
  llvm/docs/ReleaseNotes.rst
  llvm/include/llvm/CodeGen/TargetLowering.h
  llvm/lib/Target/X86/X86CallFrameOptimization.cpp
  llvm/lib/Target/X86/X86FrameLowering.cpp
  llvm/lib/Target/X86/X86FrameLowering.h
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/lib/Target/X86/X86ISelLowering.h
  llvm/lib/Target/X86/X86InstrCompiler.td
  llvm/lib/Target/X86/X86InstrInfo.td
  llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
  llvm/test/CodeGen/X86/stack-clash-large.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes-mutliple-objects.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
  llvm/test/CodeGen/X86/stack-clash-medium.ll
  llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
  llvm/test/CodeGen/X86/stack-clash-small.ll
  llvm/test/CodeGen/X86/stack-clash-unknown-call.ll

Index: llvm/test/CodeGen/X86/stack-clash-unknown-call.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-unknown-call.ll
@@ -0,0 +1,31 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+declare void @llvm.memset.p0i8.i64(i8* nocapture writeonly, i8, i64, i1 immarg);
+
+define void @foo() local_unnamed_addr #0 {
+
+;CHECK-LABEL: foo:
+;CHECK: # %bb.0:
+;CHECK-NEXT:	subq	$4096, %rsp # imm = 0x1000
+; it's important that we don't use the call as a probe here
+;CHECK-NEXT:	movq	$0, (%rsp)
+;CHECK-NEXT:	subq	$3912, %rsp # imm = 0xF48
+;CHECK-NEXT:	.cfi_def_cfa_offset 8016
+;CHECK-NEXT:	movq	%rsp, %rdi
+;CHECK-NEXT:	movl	$8000, %edx # imm = 0x1F40
+;CHECK-NEXT:	xorl	%esi, %esi
+;CHECK-NEXT:	callq	memset
+;CHECK-NEXT:	addq	$8008, %rsp # imm = 0x1F48
+;CHECK-NEXT:	.cfi_def_cfa_offset 8
+;CHECK-NEXT:	retq
+
+  %a = alloca i8, i64 8000, align 16
+  call void @llvm.memset.p0i8.i64(i8* align 16 %a, i8 0, i64 8000, i1 false)
+  ret void
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-small.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-small.ll
@@ -0,0 +1,25 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo() local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 288
+; CHECK-NEXT:  movl	$1, 264(%rsp)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i64 100, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 98
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
@@ -0,0 +1,27 @@
+; RUN: llc < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo(i64 %i) local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$4096, %rsp # imm = 0x1000
+; CHECK-NEXT:  movq	$0, (%rsp)
+; CHECK-NEXT:  subq	$3784, %rsp # imm = 0xEC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 7888
+; CHECK-NEXT:  movl	$1, -128(%rsp,%rdi,4)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$7880, %rsp # imm = 0x1EC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i32 2000, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 %i
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
+
Index: llvm/test/CodeGen/X86/stack-clash-medium.ll
===
--- /dev/null
+++ 

[PATCH] D68720: Support -fstack-clash-protection for x86

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serge-sans-paille marked 2 inline comments as done.
serge-sans-paille added inline comments.



Comment at: clang/lib/Driver/ToolChains/Clang.cpp:2910
+
+  if (Arg *A = Args.getLastArg(options::OPT_fnostack_clash_protection,
+   options::OPT_fstack_clash_protection)) {

craig.topper wrote:
> I think this can use Args.hasFlag(options::OPT_fstack_clash_protection, 
> options::OPT_fnostack_clash_protection, false) and then you don't need the 
> 'if'
I wasn't aware of that API, thanks for pointing this out o/



Comment at: llvm/lib/Target/X86/X86ISelLowering.cpp:31080
+
+  BuildMI(blockMBB, DL, TII->get(IsLP64 ? X86::SUB64ri32 : X86::SUB32ri),
+  physSPReg)

craig.topper wrote:
> This uses physSPReg, but doesn't match the condition for when physSPReg is a 
> 64-bit register. Same at several places below.
Sorry, I don't understand your remark. Can you elaborate?



Comment at: llvm/lib/Target/X86/X86InstrCompiler.td:130
+ (X86ProbedAlloca GR64:$size))]>,
+Requires<[In64BitMode]>;
 }

craig.topper wrote:
> Why is this In64BitMode, but above is NotLP64. Shouldn't they be opposites? 
> Looks like this was just copied from SEG_ALLOCA above?
Yeah, these intrinsics are just the same as the one above, except they have a 
different name. And they get lowered differently. I'm not familiar with that 
part of LLVM, can you suggest a better approach?


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[PATCH] D68720: Support -fstack-clash-protection for x86

[Craig Topper via Phabricator via cfe-commits]

craig.topper added inline comments.



Comment at: clang/include/clang/Basic/DiagnosticCommonKinds.td:243
+
+  def warn_fe_stack_clash_protection_inline_asm : Warning<
+  "Unable to protect inline asm that clobbers stack pointer against stack 
clash">;

Remove "fe_" from this? Looks like thats only there because this used to be 
DiagnosticFrontendKinds?



Comment at: clang/lib/Basic/Targets/X86.h:169
 
+  const char *getSPRegName() const override {
+if (getTriple().getArch() == llvm::Triple::x86)

This probably doesn't work correctly with X32 which is 64-bit but uses 32-bit 
pointers. Maybe we change this to "bool isSPReg(StringRef Reg)" and pass the 
register name to it so you can just check both strings always.



Comment at: clang/lib/Driver/ToolChains/Clang.cpp:2910
+
+  if (Arg *A = Args.getLastArg(options::OPT_fnostack_clash_protection,
+   options::OPT_fstack_clash_protection)) {

I think this can use Args.hasFlag(options::OPT_fstack_clash_protection, 
options::OPT_fnostack_clash_protection, false) and then you don't need the 'if'



Comment at: llvm/lib/Target/X86/X86ISelLowering.cpp:31080
+
+  BuildMI(blockMBB, DL, TII->get(IsLP64 ? X86::SUB64ri32 : X86::SUB32ri),
+  physSPReg)

This uses physSPReg, but doesn't match the condition for when physSPReg is a 
64-bit register. Same at several places below.



Comment at: llvm/lib/Target/X86/X86InstrCompiler.td:130
+ (X86ProbedAlloca GR64:$size))]>,
+Requires<[In64BitMode]>;
 }

Why is this In64BitMode, but above is NotLP64. Shouldn't they be opposites? 
Looks like this was just copied from SEG_ALLOCA above?


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[PATCH] D68720: Support -fstack-clash-protection for x86

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serge-sans-paille added a comment.

@craig.topper up?


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[PATCH] D68720: Support -fstack-clash-protection for x86

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serge-sans-paille updated this revision to Diff 237486.
serge-sans-paille added a comment.

- update warn_fe_stack_clash_protection_inline_asm location.


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Files:
  clang/docs/ClangCommandLineReference.rst
  clang/docs/ReleaseNotes.rst
  clang/include/clang/Basic/CodeGenOptions.def
  clang/include/clang/Basic/DiagnosticCommonKinds.td
  clang/include/clang/Basic/TargetInfo.h
  clang/include/clang/Driver/CC1Options.td
  clang/include/clang/Driver/Options.td
  clang/lib/Basic/Targets/X86.h
  clang/lib/CodeGen/CGStmt.cpp
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/test/CodeGen/stack-clash-protection.c
  clang/test/Driver/stack-clash-protection.c
  llvm/docs/ReleaseNotes.rst
  llvm/include/llvm/CodeGen/TargetLowering.h
  llvm/lib/Target/X86/X86CallFrameOptimization.cpp
  llvm/lib/Target/X86/X86FrameLowering.cpp
  llvm/lib/Target/X86/X86FrameLowering.h
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/lib/Target/X86/X86ISelLowering.h
  llvm/lib/Target/X86/X86InstrCompiler.td
  llvm/lib/Target/X86/X86InstrInfo.td
  llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
  llvm/test/CodeGen/X86/stack-clash-large.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes-mutliple-objects.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
  llvm/test/CodeGen/X86/stack-clash-medium.ll
  llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
  llvm/test/CodeGen/X86/stack-clash-small.ll
  llvm/test/CodeGen/X86/stack-clash-unknown-call.ll

Index: llvm/test/CodeGen/X86/stack-clash-unknown-call.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-unknown-call.ll
@@ -0,0 +1,31 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+declare void @llvm.memset.p0i8.i64(i8* nocapture writeonly, i8, i64, i1 immarg);
+
+define void @foo() local_unnamed_addr #0 {
+
+;CHECK-LABEL: foo:
+;CHECK: # %bb.0:
+;CHECK-NEXT:	subq	$4096, %rsp # imm = 0x1000
+; it's important that we don't use the call as a probe here
+;CHECK-NEXT:	movq	$0, (%rsp)
+;CHECK-NEXT:	subq	$3912, %rsp # imm = 0xF48
+;CHECK-NEXT:	.cfi_def_cfa_offset 8016
+;CHECK-NEXT:	movq	%rsp, %rdi
+;CHECK-NEXT:	movl	$8000, %edx # imm = 0x1F40
+;CHECK-NEXT:	xorl	%esi, %esi
+;CHECK-NEXT:	callq	memset
+;CHECK-NEXT:	addq	$8008, %rsp # imm = 0x1F48
+;CHECK-NEXT:	.cfi_def_cfa_offset 8
+;CHECK-NEXT:	retq
+
+  %a = alloca i8, i64 8000, align 16
+  call void @llvm.memset.p0i8.i64(i8* align 16 %a, i8 0, i64 8000, i1 false)
+  ret void
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-small.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-small.ll
@@ -0,0 +1,25 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo() local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 288
+; CHECK-NEXT:  movl	$1, 264(%rsp)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i64 100, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 98
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
@@ -0,0 +1,27 @@
+; RUN: llc < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo(i64 %i) local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$4096, %rsp # imm = 0x1000
+; CHECK-NEXT:  movq	$0, (%rsp)
+; CHECK-NEXT:  subq	$3784, %rsp # imm = 0xEC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 7888
+; CHECK-NEXT:  movl	$1, -128(%rsp,%rdi,4)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$7880, %rsp # imm = 0x1EC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i32 2000, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 %i
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
+
Index: llvm/test/CodeGen/X86/stack-clash-medium.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-medium.ll
@@ -0,0 +1,30 @@
+; 

[PATCH] D68720: Support -fstack-clash-protection for x86

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serge-sans-paille marked 2 inline comments as done.
serge-sans-paille added inline comments.



Comment at: clang/lib/CodeGen/CGStmt.cpp:2254
+CGM.getDiags().Report(S.getAsmLoc(),
+  diag::warn_fe_stack_clash_protection_inline_asm);
+  }

craig.topper wrote:
> serge-sans-paille wrote:
> > craig.topper wrote:
> > > Why is this in the frontend diagnostic list?
> > As far as I understand, that's the only place where line/col accurate 
> > diagnostics are emitted.
> I was really asking about why we have to use FrontendDiagnostic.h and 
> DriverDiagnostic.h? Is that what we normally use for diagnostics in Codegen 
> files? Seems like a possible layering issue for modules build
Oh, I understand now, let me have a look, your remark totally makes sense.


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[PATCH] D68720: Support -fstack-clash-protection for x86

[Craig Topper via Phabricator via cfe-commits]

craig.topper added inline comments.



Comment at: clang/lib/CodeGen/CGStmt.cpp:2254
+CGM.getDiags().Report(S.getAsmLoc(),
+  diag::warn_fe_stack_clash_protection_inline_asm);
+  }

serge-sans-paille wrote:
> craig.topper wrote:
> > Why is this in the frontend diagnostic list?
> As far as I understand, that's the only place where line/col accurate 
> diagnostics are emitted.
I was really asking about why we have to use FrontendDiagnostic.h and 
DriverDiagnostic.h? Is that what we normally use for diagnostics in Codegen 
files? Seems like a possible layering issue for modules build


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[PATCH] D68720: Support -fstack-clash-protection for x86

[Sylvestre Ledru via Phabricator via cfe-commits]

sylvestre.ledru added a comment.

@craig.topper do you think there is a chance that this change could be part of 
clang-10 ?
Thanks


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[PATCH] D68720: Support -fstack-clash-protection for x86

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serge-sans-paille marked 9 inline comments as done.
serge-sans-paille added inline comments.



Comment at: clang/lib/CodeGen/CGStmt.cpp:2254
+CGM.getDiags().Report(S.getAsmLoc(),
+  diag::warn_fe_stack_clash_protection_inline_asm);
+  }

craig.topper wrote:
> Why is this in the frontend diagnostic list?
As far as I understand, that's the only place where line/col accurate 
diagnostics are emitted.



Comment at: clang/lib/Driver/ToolChains/Clang.cpp:2575
+  default:
+return;
+  case llvm::Triple::ArchType::x86:

tstellar wrote:
> Do we need to warn (or error) here for arches that don't implement 
> -fstack-clash-protection?
That's done indirectly because the argument is not claimed on unsupported 
platform.


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[PATCH] D68720: Support -fstack-clash-protection for x86

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serge-sans-paille updated this revision to Diff 237298.
serge-sans-paille added a comment.

Take review into account.


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Files:
  clang/docs/ClangCommandLineReference.rst
  clang/docs/ReleaseNotes.rst
  clang/include/clang/Basic/CodeGenOptions.def
  clang/include/clang/Basic/DiagnosticFrontendKinds.td
  clang/include/clang/Basic/TargetInfo.h
  clang/include/clang/Driver/CC1Options.td
  clang/include/clang/Driver/Options.td
  clang/lib/Basic/Targets/X86.h
  clang/lib/CodeGen/CGStmt.cpp
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/test/CodeGen/stack-clash-protection.c
  clang/test/Driver/stack-clash-protection.c
  llvm/docs/ReleaseNotes.rst
  llvm/include/llvm/CodeGen/TargetLowering.h
  llvm/lib/Target/X86/X86CallFrameOptimization.cpp
  llvm/lib/Target/X86/X86FrameLowering.cpp
  llvm/lib/Target/X86/X86FrameLowering.h
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/lib/Target/X86/X86ISelLowering.h
  llvm/lib/Target/X86/X86InstrCompiler.td
  llvm/lib/Target/X86/X86InstrInfo.td
  llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
  llvm/test/CodeGen/X86/stack-clash-large.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes-mutliple-objects.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
  llvm/test/CodeGen/X86/stack-clash-medium.ll
  llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
  llvm/test/CodeGen/X86/stack-clash-small.ll
  llvm/test/CodeGen/X86/stack-clash-unknown-call.ll

Index: llvm/test/CodeGen/X86/stack-clash-unknown-call.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-unknown-call.ll
@@ -0,0 +1,31 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+declare void @llvm.memset.p0i8.i64(i8* nocapture writeonly, i8, i64, i1 immarg);
+
+define void @foo() local_unnamed_addr #0 {
+
+;CHECK-LABEL: foo:
+;CHECK: # %bb.0:
+;CHECK-NEXT:	subq	$4096, %rsp # imm = 0x1000
+; it's important that we don't use the call as a probe here
+;CHECK-NEXT:	movq	$0, (%rsp)
+;CHECK-NEXT:	subq	$3912, %rsp # imm = 0xF48
+;CHECK-NEXT:	.cfi_def_cfa_offset 8016
+;CHECK-NEXT:	movq	%rsp, %rdi
+;CHECK-NEXT:	movl	$8000, %edx # imm = 0x1F40
+;CHECK-NEXT:	xorl	%esi, %esi
+;CHECK-NEXT:	callq	memset
+;CHECK-NEXT:	addq	$8008, %rsp # imm = 0x1F48
+;CHECK-NEXT:	.cfi_def_cfa_offset 8
+;CHECK-NEXT:	retq
+
+  %a = alloca i8, i64 8000, align 16
+  call void @llvm.memset.p0i8.i64(i8* align 16 %a, i8 0, i64 8000, i1 false)
+  ret void
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-small.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-small.ll
@@ -0,0 +1,25 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo() local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 288
+; CHECK-NEXT:  movl	$1, 264(%rsp)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i64 100, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 98
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
@@ -0,0 +1,27 @@
+; RUN: llc < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo(i64 %i) local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$4096, %rsp # imm = 0x1000
+; CHECK-NEXT:  movq	$0, (%rsp)
+; CHECK-NEXT:  subq	$3784, %rsp # imm = 0xEC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 7888
+; CHECK-NEXT:  movl	$1, -128(%rsp,%rdi,4)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$7880, %rsp # imm = 0x1EC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i32 2000, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 %i
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
+
Index: llvm/test/CodeGen/X86/stack-clash-medium.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-medium.ll
@@ -0,0 +1,30 @@
+; RUN: llc < %s | FileCheck %s
+
+

[PATCH] D68720: Support -fstack-clash-protection for x86

[Tom Stellard via Phabricator via cfe-commits]

tstellar added inline comments.



Comment at: clang/lib/Driver/ToolChains/Clang.cpp:2575
+  default:
+return;
+  case llvm::Triple::ArchType::x86:

Do we need to warn (or error) here for arches that don't implement 
-fstack-clash-protection?


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[PATCH] D68720: Support -fstack-clash-protection for x86

[Craig Topper via Phabricator via cfe-commits]

craig.topper added inline comments.



Comment at: clang/docs/ClangCommandLineReference.rst:1903
 
+.. option:: -fstack-clash-protection
+

Probably need a -fno-stack-class-protection as well. Looks like gcc has it. 
You'll need to update the handling in the driver to make sure the last polarity 
wins. For cc1 you might be able to support just the positive variant. But try 
to see what we usually do.



Comment at: clang/lib/Basic/Targets/X86.h:152
 
+  const char *getSPRegName() const override { return "rsp"; }
+

What about 32-bit mode where the register name is "esp"?



Comment at: clang/lib/CodeGen/CGStmt.cpp:2254
+CGM.getDiags().Report(S.getAsmLoc(),
+  diag::warn_fe_stack_clash_protection_inline_asm);
+  }

Why is this in the frontend diagnostic list?



Comment at: clang/lib/Driver/ToolChains/Clang.cpp:2573
+
+  switch (EffectiveTriple.getArch()) {
+  default:

Can we use EffectiveTriple.isX86() that was just introduced yesterday?



Comment at: clang/lib/Driver/ToolChains/Clang.cpp:2582
+  for (const Arg *A : Args) {
+switch (A->getOption().getID()) {
+default:

Seems like this should just be an if? Or maybe use Args.filtered or args 
getLastArg?


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[PATCH] D68720: Support -fstack-clash-protection for x86

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serge-sans-paille added a comment.

@rnk up? the mozilla folks confirmed there's no significant regression (see 
https://bugzilla.mozilla.org/show_bug.cgi?id=1588710#c12).


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[PATCH] D68720: Support -fstack-clash-protection for x86

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serge-sans-paille added a comment.

@sylvestre.ledru backport for  release/9.x branch: 
https://sergesanspaille.fedorapeople.org/0001-Stack-clash-mir-attempt.patch


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[PATCH] D68720: Support -fstack-clash-protection for x86

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serge-sans-paille added a comment.

For the record : this validates fine on OSX, Linux and Windows, using the 
github actions setup by @tstellar

https://github.com/serge-sans-paille/llvm-project/pull/3


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[PATCH] D68720: Support -fstack-clash-protection for x86

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serge-sans-paille added a comment.

In D68720#1755546 , @xbolva00 wrote:

> https://reviews.llvm.org/rG397fa687691876de9ff0fbaaf0def3ac5a48899c
>
> Commited?


No, still waiting for @rnk feedback. This commit is just me using the wrong 
remote when pushing for validation.


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serge-sans-paille updated this revision to Diff 230494.
serge-sans-paille added a comment.

Added extra test for arch support (warns if the flag is used on unsupported 
targets, and checks it's effectively unused), cc @sylvestre.ledru


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Files:
  clang/docs/ClangCommandLineReference.rst
  clang/docs/ReleaseNotes.rst
  clang/include/clang/Basic/CodeGenOptions.def
  clang/include/clang/Basic/DiagnosticFrontendKinds.td
  clang/include/clang/Basic/TargetInfo.h
  clang/include/clang/Driver/CC1Options.td
  clang/include/clang/Driver/Options.td
  clang/lib/Basic/Targets/X86.h
  clang/lib/CodeGen/CGStmt.cpp
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/test/CodeGen/stack-clash-protection.c
  clang/test/Driver/stack-clash-protection.c
  llvm/docs/ReleaseNotes.rst
  llvm/include/llvm/CodeGen/TargetLowering.h
  llvm/lib/Target/X86/X86CallFrameOptimization.cpp
  llvm/lib/Target/X86/X86FrameLowering.cpp
  llvm/lib/Target/X86/X86FrameLowering.h
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/lib/Target/X86/X86ISelLowering.h
  llvm/lib/Target/X86/X86InstrCompiler.td
  llvm/lib/Target/X86/X86InstrInfo.td
  llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
  llvm/test/CodeGen/X86/stack-clash-large.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes-mutliple-objects.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
  llvm/test/CodeGen/X86/stack-clash-medium.ll
  llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
  llvm/test/CodeGen/X86/stack-clash-small.ll
  llvm/test/CodeGen/X86/stack-clash-unknown-call.ll

Index: llvm/test/CodeGen/X86/stack-clash-unknown-call.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-unknown-call.ll
@@ -0,0 +1,31 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+declare void @llvm.memset.p0i8.i64(i8* nocapture writeonly, i8, i64, i1 immarg);
+
+define void @foo() local_unnamed_addr #0 {
+
+;CHECK-LABEL: foo:
+;CHECK: # %bb.0:
+;CHECK-NEXT:	subq	$4096, %rsp # imm = 0x1000
+; it's important that we don't use the call as a probe here
+;CHECK-NEXT:	movq	$0, (%rsp)
+;CHECK-NEXT:	subq	$3912, %rsp # imm = 0xF48
+;CHECK-NEXT:	.cfi_def_cfa_offset 8016
+;CHECK-NEXT:	movq	%rsp, %rdi
+;CHECK-NEXT:	movl	$8000, %edx # imm = 0x1F40
+;CHECK-NEXT:	xorl	%esi, %esi
+;CHECK-NEXT:	callq	memset
+;CHECK-NEXT:	addq	$8008, %rsp # imm = 0x1F48
+;CHECK-NEXT:	.cfi_def_cfa_offset 8
+;CHECK-NEXT:	retq
+
+  %a = alloca i8, i64 8000, align 16
+  call void @llvm.memset.p0i8.i64(i8* align 16 %a, i8 0, i64 8000, i1 false)
+  ret void
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-small.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-small.ll
@@ -0,0 +1,25 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo() local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 288
+; CHECK-NEXT:  movl	$1, 264(%rsp)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i64 100, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 98
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
@@ -0,0 +1,27 @@
+; RUN: llc < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo(i64 %i) local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$4096, %rsp # imm = 0x1000
+; CHECK-NEXT:  movq	$0, (%rsp)
+; CHECK-NEXT:  subq	$3784, %rsp # imm = 0xEC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 7888
+; CHECK-NEXT:  movl	$1, -128(%rsp,%rdi,4)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$7880, %rsp # imm = 0x1EC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i32 2000, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 %i
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
+
Index: llvm/test/CodeGen/X86/stack-clash-medium.ll
===

[PATCH] D68720: Support -fstack-clash-protection for x86

[Dávid Bolvanský via Phabricator via cfe-commits]

xbolva00 added a comment.

https://reviews.llvm.org/rG397fa687691876de9ff0fbaaf0def3ac5a48899c

Commited?


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serge-sans-paille added a comment.

@rnk : up ?


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[PATCH] D68720: Support -fstack-clash-protection for x86

[Sylvestre Ledru via Phabricator via cfe-commits]

sylvestre.ledru added a comment.

In D68720#1733839 , @serge-sans-paille 
wrote:

> @sylvestre.ledru did the testing and benchmarking on firefox (see 
> https://bugzilla.mozilla.org/show_bug.cgi?id=1588710#c12), everything seems 
> ok, let's move forward?


Actually, not sure about the benchmark anymore. I am checking with experts. 
Sorry


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serge-sans-paille added a comment.

@sylvestre.ledru did the testing and benchmarking on firefox (see 
https://bugzilla.mozilla.org/show_bug.cgi?id=1588710#c12), everything seems ok, 
let's move forward?


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serge-sans-paille added a comment.

@sylvestre.ledru : quick backport for llvm9: 
https://sergesanspaille.fedorapeople.org/0001-Stack-clash-mir-attempt.patch


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@rnk what's your take on that version?


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[PATCH] D68720: Support -fstack-clash-protection for x86

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serge-sans-paille updated this revision to Diff 227194.
serge-sans-paille edited the summary of this revision.
serge-sans-paille added a comment.

Moved to a simpler, easier to review, less error prone implementation. 
Validates just fines on llvm bootstrap an cpython code base. @sylvestre.ledru 
that's the patch you can play with.


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Files:
  clang/docs/ClangCommandLineReference.rst
  clang/docs/ReleaseNotes.rst
  clang/include/clang/Basic/CodeGenOptions.def
  clang/include/clang/Basic/DiagnosticFrontendKinds.td
  clang/include/clang/Basic/TargetInfo.h
  clang/include/clang/Driver/CC1Options.td
  clang/include/clang/Driver/Options.td
  clang/lib/Basic/Targets/X86.h
  clang/lib/CodeGen/CGStmt.cpp
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/test/CodeGen/stack-clash-protection.c
  clang/test/Driver/stack-clash-protection.c
  llvm/docs/ReleaseNotes.rst
  llvm/include/llvm/CodeGen/TargetLowering.h
  llvm/lib/Target/X86/X86CallFrameOptimization.cpp
  llvm/lib/Target/X86/X86FrameLowering.cpp
  llvm/lib/Target/X86/X86FrameLowering.h
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/lib/Target/X86/X86ISelLowering.h
  llvm/lib/Target/X86/X86InstrCompiler.td
  llvm/lib/Target/X86/X86InstrInfo.td
  llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
  llvm/test/CodeGen/X86/stack-clash-large.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes-mutliple-objects.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
  llvm/test/CodeGen/X86/stack-clash-medium.ll
  llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
  llvm/test/CodeGen/X86/stack-clash-small.ll
  llvm/test/CodeGen/X86/stack-clash-unknown-call.ll

Index: llvm/test/CodeGen/X86/stack-clash-unknown-call.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-unknown-call.ll
@@ -0,0 +1,31 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+declare void @llvm.memset.p0i8.i64(i8* nocapture writeonly, i8, i64, i1 immarg);
+
+define void @foo() local_unnamed_addr #0 {
+
+;CHECK-LABEL: foo:
+;CHECK: # %bb.0:
+;CHECK-NEXT:	subq	$4096, %rsp # imm = 0x1000
+; it's important that we don't use the call as a probe here
+;CHECK-NEXT:	movq	$0, (%rsp)
+;CHECK-NEXT:	subq	$3912, %rsp # imm = 0xF48
+;CHECK-NEXT:	.cfi_def_cfa_offset 8016
+;CHECK-NEXT:	movq	%rsp, %rdi
+;CHECK-NEXT:	movl	$8000, %edx # imm = 0x1F40
+;CHECK-NEXT:	xorl	%esi, %esi
+;CHECK-NEXT:	callq	memset
+;CHECK-NEXT:	addq	$8008, %rsp # imm = 0x1F48
+;CHECK-NEXT:	.cfi_def_cfa_offset 8
+;CHECK-NEXT:	retq
+
+  %a = alloca i8, i64 8000, align 16
+  call void @llvm.memset.p0i8.i64(i8* align 16 %a, i8 0, i64 8000, i1 false)
+  ret void
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-small.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-small.ll
@@ -0,0 +1,25 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo() local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 288
+; CHECK-NEXT:  movl	$1, 264(%rsp)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i64 100, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 98
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
@@ -0,0 +1,27 @@
+; RUN: llc < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo(i64 %i) local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$4096, %rsp # imm = 0x1000
+; CHECK-NEXT:  movq	$0, (%rsp)
+; CHECK-NEXT:  subq	$3784, %rsp # imm = 0xEC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 7888
+; CHECK-NEXT:  movl	$1, -128(%rsp,%rdi,4)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$7880, %rsp # imm = 0x1EC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i32 2000, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 %i
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
+
Index: 

[PATCH] D68720: Support -fstack-clash-protection for x86

[Sylvestre Ledru via Phabricator via cfe-commits]

sylvestre.ledru added inline comments.



Comment at: clang/docs/ClangCommandLineReference.rst:1901
+
+Instrument stack allocation to prevent stack clash attacks.
+

Maybe add that it is Linux only? :)



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[PATCH] D68720: Support -fstack-clash-protection for x86

[serge via Phabricator via cfe-commits]

serge-sans-paille updated this revision to Diff 226109.
serge-sans-paille added a comment.

Temporarily comment out call support as free probe, everything else passes 
validation but a call may have some stack effect I don't handle (yet).


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Files:
  clang/docs/ClangCommandLineReference.rst
  clang/docs/ReleaseNotes.rst
  clang/include/clang/Basic/CodeGenOptions.def
  clang/include/clang/Basic/DiagnosticFrontendKinds.td
  clang/include/clang/Basic/TargetInfo.h
  clang/include/clang/Driver/CC1Options.td
  clang/include/clang/Driver/Options.td
  clang/lib/Basic/Targets/X86.h
  clang/lib/CodeGen/CGStmt.cpp
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/test/CodeGen/stack-clash-protection.c
  clang/test/Driver/stack-clash-protection.c
  llvm/docs/ReleaseNotes.rst
  llvm/include/llvm/CodeGen/TargetLowering.h
  llvm/lib/Target/X86/X86CallFrameOptimization.cpp
  llvm/lib/Target/X86/X86FrameLowering.cpp
  llvm/lib/Target/X86/X86FrameLowering.h
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/lib/Target/X86/X86ISelLowering.h
  llvm/lib/Target/X86/X86InstrCompiler.td
  llvm/lib/Target/X86/X86InstrInfo.td
  llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
  llvm/test/CodeGen/X86/stack-clash-large.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes-mutliple-objects.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
  llvm/test/CodeGen/X86/stack-clash-medium.ll
  llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
  llvm/test/CodeGen/X86/stack-clash-small.ll
  llvm/test/CodeGen/X86/stack-clash-unknown-call.ll

Index: llvm/test/CodeGen/X86/stack-clash-unknown-call.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-unknown-call.ll
@@ -0,0 +1,31 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+declare void @llvm.memset.p0i8.i64(i8* nocapture writeonly, i8, i64, i1 immarg);
+
+define void @foo() local_unnamed_addr #0 {
+
+;CHECK-LABEL: foo:
+;CHECK: # %bb.0:
+;CHECK-NEXT:	subq	$4096, %rsp # imm = 0x1000
+; it's important that we don't use the call as a probe here
+;CHECK-NEXT:	movq	$0, (%rsp)
+;CHECK-NEXT:	subq	$3912, %rsp # imm = 0xF48
+;CHECK-NEXT:	.cfi_def_cfa_offset 8016
+;CHECK-NEXT:	movq	%rsp, %rdi
+;CHECK-NEXT:	movl	$8000, %edx # imm = 0x1F40
+;CHECK-NEXT:	xorl	%esi, %esi
+;CHECK-NEXT:	callq	memset
+;CHECK-NEXT:	addq	$8008, %rsp # imm = 0x1F48
+;CHECK-NEXT:	.cfi_def_cfa_offset 8
+;CHECK-NEXT:	retq
+
+  %a = alloca i8, i64 8000, align 16
+  call void @llvm.memset.p0i8.i64(i8* align 16 %a, i8 0, i64 8000, i1 false)
+  ret void
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-small.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-small.ll
@@ -0,0 +1,25 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo() local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 288
+; CHECK-NEXT:  movl	$1, 264(%rsp)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i64 100, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 98
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
@@ -0,0 +1,27 @@
+; RUN: llc < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo(i64 %i) local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$4096, %rsp # imm = 0x1000
+; CHECK-NEXT:  movq	$0, (%rsp)
+; CHECK-NEXT:  subq	$3784, %rsp # imm = 0xEC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 7888
+; CHECK-NEXT:  movl	$1, -128(%rsp,%rdi,4)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$7880, %rsp # imm = 0x1EC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i32 2000, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 %i
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
+
Index: llvm/test/CodeGen/X86/stack-clash-medium.ll
===
--- /dev/null
+++ 

[PATCH] D68720: Support -fstack-clash-protection for x86

[serge via Phabricator via cfe-commits]

serge-sans-paille added a comment.

Some benchmark / instrumentation report: due to the way memory moves are 
ordered in the entry block, there tend to be relatively few free probes between 
two stack growth within a function, and a large number after the last stack 
growth.

When recompiling llc, I only get 18 free probes between stack growth, and a 
large amount (several thousands) after the last stack growth.
When recompiling cpython, I only get 4 free probes between stack growth.

This may be improved by rescheduling instructions / changing stack object 
layout but that's probably not worth the effort (there's not that much 
functions with stack space > a page)


Repository:
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[PATCH] D68720: Support -fstack-clash-protection for x86

[serge via Phabricator via cfe-commits]

serge-sans-paille updated this revision to Diff 226043.
serge-sans-paille added a comment.

Update documentation as suggested by @sylvestre.ledru 
Corner case when a write was touching memory beyond the allocated stack.


Repository:
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CHANGES SINCE LAST ACTION
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Files:
  clang/docs/ReleaseNotes.rst
  clang/include/clang/Basic/CodeGenOptions.def
  clang/include/clang/Basic/DiagnosticFrontendKinds.td
  clang/include/clang/Basic/TargetInfo.h
  clang/include/clang/Driver/CC1Options.td
  clang/include/clang/Driver/Options.td
  clang/lib/Basic/Targets/X86.h
  clang/lib/CodeGen/CGStmt.cpp
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/test/CodeGen/stack-clash-protection.c
  clang/test/Driver/stack-clash-protection.c
  llvm/docs/ReleaseNotes.rst
  llvm/include/llvm/CodeGen/TargetLowering.h
  llvm/lib/Target/X86/X86CallFrameOptimization.cpp
  llvm/lib/Target/X86/X86FrameLowering.cpp
  llvm/lib/Target/X86/X86FrameLowering.h
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/lib/Target/X86/X86ISelLowering.h
  llvm/lib/Target/X86/X86InstrCompiler.td
  llvm/lib/Target/X86/X86InstrInfo.td
  llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
  llvm/test/CodeGen/X86/stack-clash-large.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes-mutliple-objects.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
  llvm/test/CodeGen/X86/stack-clash-medium.ll
  llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
  llvm/test/CodeGen/X86/stack-clash-small.ll
  llvm/test/CodeGen/X86/stack-clash-unknown-call.ll

Index: llvm/test/CodeGen/X86/stack-clash-unknown-call.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-unknown-call.ll
@@ -0,0 +1,31 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+declare void @llvm.memset.p0i8.i64(i8* nocapture writeonly, i8, i64, i1 immarg);
+
+define void @foo() local_unnamed_addr #0 {
+
+;CHECK-LABEL: foo:
+;CHECK: # %bb.0:
+;CHECK-NEXT:	subq	$4096, %rsp # imm = 0x1000
+; it's important that we don't use the call as a probe here
+;CHECK-NEXT:	movq	$0, (%rsp)
+;CHECK-NEXT:	subq	$3912, %rsp # imm = 0xF48
+;CHECK-NEXT:	.cfi_def_cfa_offset 8016
+;CHECK-NEXT:	movq	%rsp, %rdi
+;CHECK-NEXT:	movl	$8000, %edx # imm = 0x1F40
+;CHECK-NEXT:	xorl	%esi, %esi
+;CHECK-NEXT:	callq	memset
+;CHECK-NEXT:	addq	$8008, %rsp # imm = 0x1F48
+;CHECK-NEXT:	.cfi_def_cfa_offset 8
+;CHECK-NEXT:	retq
+
+  %a = alloca i8, i64 8000, align 16
+  call void @llvm.memset.p0i8.i64(i8* align 16 %a, i8 0, i64 8000, i1 false)
+  ret void
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-small.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-small.ll
@@ -0,0 +1,25 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo() local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 288
+; CHECK-NEXT:  movl	$1, 264(%rsp)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i64 100, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 98
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
@@ -0,0 +1,27 @@
+; RUN: llc < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo(i64 %i) local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$4096, %rsp # imm = 0x1000
+; CHECK-NEXT:  movq	$0, (%rsp)
+; CHECK-NEXT:  subq	$3784, %rsp # imm = 0xEC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 7888
+; CHECK-NEXT:  movl	$1, -128(%rsp,%rdi,4)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$7880, %rsp # imm = 0x1EC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i32 2000, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 %i
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
+
Index: llvm/test/CodeGen/X86/stack-clash-medium.ll
===
--- /dev/null
+++ 

[PATCH] D68720: Support -fstack-clash-protection for x86

[serge via Phabricator via cfe-commits]

serge-sans-paille updated this revision to Diff 226002.
serge-sans-paille added a comment.

Better integration with MachineInstr description
Handle stacks with multiple stack objects
More test case


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D68720/new/

https://reviews.llvm.org/D68720

Files:
  clang/docs/ReleaseNotes.rst
  clang/include/clang/Basic/CodeGenOptions.def
  clang/include/clang/Basic/DiagnosticFrontendKinds.td
  clang/include/clang/Basic/TargetInfo.h
  clang/include/clang/Driver/CC1Options.td
  clang/include/clang/Driver/Options.td
  clang/lib/Basic/Targets/X86.h
  clang/lib/CodeGen/CGStmt.cpp
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/test/CodeGen/stack-clash-protection.c
  clang/test/Driver/stack-clash-protection.c
  llvm/docs/ReleaseNotes.rst
  llvm/include/llvm/CodeGen/TargetLowering.h
  llvm/lib/Target/X86/X86CallFrameOptimization.cpp
  llvm/lib/Target/X86/X86FrameLowering.cpp
  llvm/lib/Target/X86/X86FrameLowering.h
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/lib/Target/X86/X86ISelLowering.h
  llvm/lib/Target/X86/X86InstrCompiler.td
  llvm/lib/Target/X86/X86InstrInfo.td
  llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
  llvm/test/CodeGen/X86/stack-clash-large.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes-mutliple-objects.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
  llvm/test/CodeGen/X86/stack-clash-medium.ll
  llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
  llvm/test/CodeGen/X86/stack-clash-small.ll
  llvm/test/CodeGen/X86/stack-clash-unknown-call.ll

Index: llvm/test/CodeGen/X86/stack-clash-unknown-call.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-unknown-call.ll
@@ -0,0 +1,31 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+declare void @llvm.memset.p0i8.i64(i8* nocapture writeonly, i8, i64, i1 immarg);
+
+define void @foo() local_unnamed_addr #0 {
+
+;CHECK-LABEL: foo:
+;CHECK: # %bb.0:
+;CHECK-NEXT:	subq	$4096, %rsp # imm = 0x1000
+; it's important that we don't use the call as a probe here
+;CHECK-NEXT:	movq	$0, (%rsp)
+;CHECK-NEXT:	subq	$3912, %rsp # imm = 0xF48
+;CHECK-NEXT:	.cfi_def_cfa_offset 8016
+;CHECK-NEXT:	movq	%rsp, %rdi
+;CHECK-NEXT:	movl	$8000, %edx # imm = 0x1F40
+;CHECK-NEXT:	xorl	%esi, %esi
+;CHECK-NEXT:	callq	memset
+;CHECK-NEXT:	addq	$8008, %rsp # imm = 0x1F48
+;CHECK-NEXT:	.cfi_def_cfa_offset 8
+;CHECK-NEXT:	retq
+
+  %a = alloca i8, i64 8000, align 16
+  call void @llvm.memset.p0i8.i64(i8* align 16 %a, i8 0, i64 8000, i1 false)
+  ret void
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-small.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-small.ll
@@ -0,0 +1,25 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo() local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 288
+; CHECK-NEXT:  movl	$1, 264(%rsp)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i64 100, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 98
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
@@ -0,0 +1,27 @@
+; RUN: llc < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo(i64 %i) local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$4096, %rsp # imm = 0x1000
+; CHECK-NEXT:  movq	$0, (%rsp)
+; CHECK-NEXT:  subq	$3784, %rsp # imm = 0xEC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 7888
+; CHECK-NEXT:  movl	$1, -128(%rsp,%rdi,4)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$7880, %rsp # imm = 0x1EC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i32 2000, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 %i
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
+
Index: llvm/test/CodeGen/X86/stack-clash-medium.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-medium.ll
@@ -0,0 +1,27 @@

[PATCH] D68720: Support -fstack-clash-protection for x86

[Sylvestre Ledru via Phabricator via cfe-commits]

sylvestre.ledru added a comment.

You should also probably document the arg in
clang/docs/ClangCommandLineReference.rst 
we have  -fstack-protector-strong & co in the doc


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[PATCH] D68720: Support -fstack-clash-protection for x86

[serge via Phabricator via cfe-commits]

serge-sans-paille updated this revision to Diff 225580.
serge-sans-paille added a comment.

Explicilty prefer existing mechanism for windows.
Split loop/block allocation strategy to different functions.


Repository:
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CHANGES SINCE LAST ACTION
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Files:
  clang/docs/ReleaseNotes.rst
  clang/include/clang/Basic/CodeGenOptions.def
  clang/include/clang/Basic/DiagnosticFrontendKinds.td
  clang/include/clang/Basic/TargetInfo.h
  clang/include/clang/Driver/CC1Options.td
  clang/include/clang/Driver/Options.td
  clang/lib/Basic/Targets/X86.h
  clang/lib/CodeGen/CGStmt.cpp
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/test/CodeGen/stack-clash-protection.c
  clang/test/Driver/stack-clash-protection.c
  llvm/docs/ReleaseNotes.rst
  llvm/include/llvm/CodeGen/TargetLowering.h
  llvm/lib/Target/X86/X86CallFrameOptimization.cpp
  llvm/lib/Target/X86/X86FrameLowering.cpp
  llvm/lib/Target/X86/X86FrameLowering.h
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/lib/Target/X86/X86ISelLowering.h
  llvm/lib/Target/X86/X86InstrCompiler.td
  llvm/lib/Target/X86/X86InstrInfo.td
  llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
  llvm/test/CodeGen/X86/stack-clash-large.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
  llvm/test/CodeGen/X86/stack-clash-medium.ll
  llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
  llvm/test/CodeGen/X86/stack-clash-small.ll

Index: llvm/test/CodeGen/X86/stack-clash-small.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-small.ll
@@ -0,0 +1,25 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo() local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 288
+; CHECK-NEXT:  movl	$1, 264(%rsp)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i64 100, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 98
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
@@ -0,0 +1,27 @@
+; RUN: llc < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo(i64 %i) local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$4096, %rsp # imm = 0x1000
+; CHECK-NEXT:  movq	$0, (%rsp)
+; CHECK-NEXT:  subq	$3784, %rsp # imm = 0xEC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 7888
+; CHECK-NEXT:  movl	$1, -128(%rsp,%rdi,4)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$7880, %rsp # imm = 0x1EC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i32 2000, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 %i
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
+
Index: llvm/test/CodeGen/X86/stack-clash-medium.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-medium.ll
@@ -0,0 +1,28 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo() local_unnamed_addr #0 {
+
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$4096, %rsp # imm = 0x1000
+; CHECK-NEXT:  .cfi_def_cfa_offset 7888
+; CHECK-NEXT:  movl	$1, 880(%rsp)
+; CHECK-NEXT:  subq	$3784, %rsp # imm = 0xEC8
+; CHECK-NEXT:  movq	$0, (%rsp)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$7880, %rsp # imm = 0x1EC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i64 2000, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 1198
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
@@ -0,0 +1,31 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo() local_unnamed_addr #0 {
+
+; CHECK-LABEL: foo:
+; CHECK: # %bb.0:
+; CHECK-NEXT: 	 

[PATCH] D68720: Support -fstack-clash-protection for x86

[serge via Phabricator via cfe-commits]

serge-sans-paille added a comment.

Extra note: an older version of the patch has been tested by the firefox team 
without much performance impact, (and no test failure), see 
https://bugzilla.mozilla.org/show_bug.cgi?id=1588710


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[PATCH] D68720: Support -fstack-clash-protection for x86

[serge via Phabricator via cfe-commits]

serge-sans-paille updated this revision to Diff 225462.
serge-sans-paille added a comment.

Moved the implementation to a specialization of `emitStackProbeInline` that 
used to be Windows-centric. Provide a generic implementation that generates 
inline assembly instead. that way we don't clutter existing functions, and only 
add a new case to `emitSPUpdate`.

Handle large stack allocation with a loop instead of a (large) basic block.

@rnk: this is far less intrusive and more integrated to the existing structure, 
thanks a lot for hinting in that direction.


Repository:
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CHANGES SINCE LAST ACTION
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Files:
  clang/docs/ReleaseNotes.rst
  clang/include/clang/Basic/CodeGenOptions.def
  clang/include/clang/Basic/DiagnosticFrontendKinds.td
  clang/include/clang/Basic/TargetInfo.h
  clang/include/clang/Driver/CC1Options.td
  clang/include/clang/Driver/Options.td
  clang/lib/Basic/Targets/X86.h
  clang/lib/CodeGen/CGStmt.cpp
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/test/CodeGen/stack-clash-protection.c
  clang/test/Driver/stack-clash-protection.c
  llvm/docs/ReleaseNotes.rst
  llvm/include/llvm/CodeGen/TargetLowering.h
  llvm/lib/Target/X86/X86CallFrameOptimization.cpp
  llvm/lib/Target/X86/X86FrameLowering.cpp
  llvm/lib/Target/X86/X86FrameLowering.h
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/lib/Target/X86/X86ISelLowering.h
  llvm/lib/Target/X86/X86InstrCompiler.td
  llvm/lib/Target/X86/X86InstrInfo.td
  llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
  llvm/test/CodeGen/X86/stack-clash-large.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
  llvm/test/CodeGen/X86/stack-clash-medium.ll
  llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
  llvm/test/CodeGen/X86/stack-clash-small.ll

Index: llvm/test/CodeGen/X86/stack-clash-small.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-small.ll
@@ -0,0 +1,25 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo() local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 288
+; CHECK-NEXT:  movl	$1, 264(%rsp)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i64 100, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 98
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
@@ -0,0 +1,27 @@
+; RUN: llc < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo(i64 %i) local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$4096, %rsp # imm = 0x1000
+; CHECK-NEXT:  movq	$0, (%rsp)
+; CHECK-NEXT:  subq	$3784, %rsp # imm = 0xEC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 7888
+; CHECK-NEXT:  movl	$1, -128(%rsp,%rdi,4)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$7880, %rsp # imm = 0x1EC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i32 2000, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 %i
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
+
Index: llvm/test/CodeGen/X86/stack-clash-medium.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-medium.ll
@@ -0,0 +1,28 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo() local_unnamed_addr #0 {
+
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$4096, %rsp # imm = 0x1000
+; CHECK-NEXT:  .cfi_def_cfa_offset 7888
+; CHECK-NEXT:  movl	$1, 880(%rsp)
+; CHECK-NEXT:  subq	$3784, %rsp # imm = 0xEC8
+; CHECK-NEXT:  movq	$0, (%rsp)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$7880, %rsp # imm = 0x1EC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i64 2000, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 1198
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll

[PATCH] D68720: Support -fstack-clash-protection for x86

[serge via Phabricator via cfe-commits]

serge-sans-paille updated this revision to Diff 225049.
serge-sans-paille added a comment.

Get rid of static mapping + update test cases


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D68720/new/

https://reviews.llvm.org/D68720

Files:
  clang/docs/ReleaseNotes.rst
  clang/include/clang/Basic/CodeGenOptions.def
  clang/include/clang/Basic/DiagnosticFrontendKinds.td
  clang/include/clang/Basic/TargetInfo.h
  clang/include/clang/Driver/CC1Options.td
  clang/include/clang/Driver/Options.td
  clang/lib/Basic/Targets/X86.h
  clang/lib/CodeGen/CGStmt.cpp
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/test/CodeGen/stack-clash-protection.c
  clang/test/Driver/stack-clash-protection.c
  llvm/docs/ReleaseNotes.rst
  llvm/include/llvm/CodeGen/TargetLowering.h
  llvm/lib/Target/X86/X86CallFrameOptimization.cpp
  llvm/lib/Target/X86/X86FrameLowering.cpp
  llvm/lib/Target/X86/X86FrameLowering.h
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/lib/Target/X86/X86ISelLowering.h
  llvm/lib/Target/X86/X86InstrCompiler.td
  llvm/lib/Target/X86/X86InstrInfo.td
  llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
  llvm/test/CodeGen/X86/stack-clash-medium.ll
  llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
  llvm/test/CodeGen/X86/stack-clash-small.ll

Index: llvm/test/CodeGen/X86/stack-clash-small.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-small.ll
@@ -0,0 +1,25 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo() local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 288
+; CHECK-NEXT:  movl	$1, 264(%rsp)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$280, %rsp # imm = 0x118
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i64 100, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 98
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
@@ -0,0 +1,27 @@
+; RUN: llc < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo(i64 %i) local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$4096, %rsp # imm = 0x1000
+; CHECK-NEXT:  movq	$0, (%rsp)
+; CHECK-NEXT:  subq	$3784, %rsp # imm = 0xEC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 7888
+; CHECK-NEXT:  movl	$1, -128(%rsp,%rdi,4)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$7880, %rsp # imm = 0x1EC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i32 2000, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 %i
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
+
Index: llvm/test/CodeGen/X86/stack-clash-medium.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-medium.ll
@@ -0,0 +1,28 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo() local_unnamed_addr #0 {
+
+; CHECK-LABEL: foo:
+; CHECK:   # %bb.0:
+; CHECK-NEXT:  subq	$4096, %rsp # imm = 0x1000
+; CHECK-NEXT:  .cfi_def_cfa_offset 7888
+; CHECK-NEXT:  movl	$1, 880(%rsp)
+; CHECK-NEXT:  subq	$3784, %rsp # imm = 0xEC8
+; CHECK-NEXT:  movq	$0, (%rsp)
+; CHECK-NEXT:  movl	-128(%rsp), %eax
+; CHECK-NEXT:  addq	$7880, %rsp # imm = 0x1EC8
+; CHECK-NEXT:  .cfi_def_cfa_offset 8
+; CHECK-NEXT:  retq
+
+  %a = alloca i32, i64 2000, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 1198
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
@@ -0,0 +1,31 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo() local_unnamed_addr #0 {
+
+; CHECK-LABEL: foo:
+; CHECK: # %bb.0:
+; CHECK-NEXT: 	 subq	$4096, %rsp # imm = 0x1000
+; CHECK-NEXT: 	 .cfi_def_cfa_offset 7888
+; CHECK-NEXT: 	 movl	$1, 264(%rsp)

[PATCH] D68720: Support -fstack-clash-protection for x86

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serge-sans-paille added a comment.

Another test run on an x264 encoder (source: 
https://openbenchmarking.org/test/pts/x264)

Compiled with -O2 and with or without -fstack-clash-protection; Run without 
threads (`x265 --pools 1 -F 1 ./Bosphorus_1920x1080_120fps_420_8bit_YUV.y4m 
/dev/null`)

**Clang**

  baseline:  318.60s 
  protection:  317.72s

So no performance impact beyond noise.

The compilation inserts 44 inline probes in 9 functions.

**gcc**

Out of comparison, with gcc 8.2 (yeah, it's a bit old), I get (same flags & 
setup)

  baseline : 417.53 sec
  protected : 412.6 sec 

The compilations inserts inline probes in 22 functions.
So gcc inserts more probes, the impact on performance is equally surprising. I 
need to gather more points to get some statistical informations there.


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[PATCH] D68720: Support -fstack-clash-protection for x86

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serge-sans-paille added a comment.

> For maintenance reasons, I'd really prefer it if we could find a way to reuse 
> the existing code that calls an external stack probe function. What do you 
> think about taking a look at X86RetpolineThunks.cpp and doing something 
> similar to that? Basically, when the user sets -fstack-clash-protection, LLVM 
> will emit a small comdat+weak function into every object file that has the 
> same ABI as the existing stack probe mechanism. For other prior art, you can 
> also look at how __clang_call_terminate works.

@rnk I 100% understand the reasoning, and will have a look to the files you're 
pointing at. AFAIU the approach you're suggesting is incompatible with the « 
free probe » algorithm that moves instruction in between stack allocations, but 
let me confirm that first.


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[PATCH] D68720: Support -fstack-clash-protection for x86

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serge-sans-paille added a comment.

Some benchmarks, running the python performance suite from recompiled cpython 
build, one built with `-O2` (baseline) and one built with `-O2 
-fstack-clash-protection` (protection). Surprisingly enough, the stack 
protection makes the code faster in various scenario, but none of these changes 
present significant regression, according to me.

  baseline.json
  =
  
  Performance version: 0.9.1
  Report on Linux-3.10.0-891.el7.x86_64-x86_64-with-redhat-7.5-Maipo
  Number of logical CPUs: 8
  Start date: 2019-10-15 11:16:28.425344
  End date: 2019-10-15 11:37:55.064599
  
  protection.json
  ===
  
  Performance version: 0.9.1
  Report on Linux-3.10.0-891.el7.x86_64-x86_64-with-redhat-7.5-Maipo
  Number of logical CPUs: 8
  Start date: 2019-10-15 10:55:24.270166
  End date: 2019-10-15 11:16:27.195366
  
  
+-+---+-+--+---+
  | Benchmark   | baseline.json | protection.json | Change   | 
Significance  |
  
+=+===+=+==+===+
  | 2to3| 435 ms| 448 ms  | 1.03x slower | 
Significant (t=-4.26) |
  
+-+---+-+--+---+
  | chameleon   | 15.0 ms   | 14.7 ms | 1.02x faster | 
Significant (t=4.76)  |
  
+-+---+-+--+---+
  | chaos   | 176 ms| 174 ms  | 1.02x faster | 
Not significant   |
  
+-+---+-+--+---+
  | crypto_pyaes| 153 ms| 150 ms  | 1.02x faster | 
Not significant   |
  
+-+---+-+--+---+
  | deltablue   | 11.9 ms   | 11.9 ms | 1.00x slower | 
Not significant   |
  
+-+---+-+--+---+
  | django_template | 210 ms| 223 ms  | 1.06x slower | 
Significant (t=-3.84) |
  
+-+---+-+--+---+
  | dulwich_log | 96.1 ms   | 102 ms  | 1.06x slower | 
Significant (t=-8.42) |
  
+-+---+-+--+---+
  | fannkuch| 703 ms| 698 ms  | 1.01x faster | 
Not significant   |
  
+-+---+-+--+---+
  | float   | 161 ms| 160 ms  | 1.01x faster | 
Not significant   |
  
+-+---+-+--+---+
  | genshi_text | 45.5 ms   | 45.5 ms | 1.00x faster | 
Not significant   |
  
+-+---+-+--+---+
  | genshi_xml  | 95.3 ms   | 95.2 ms | 1.00x faster | 
Not significant   |
  
+-+---+-+--+---+
  | go  | 392 ms| 382 ms  | 1.03x faster | 
Significant (t=5.95)  |
  
+-+---+-+--+---+
  | hexiom  | 16.0 ms   | 15.9 ms | 1.01x faster | 
Not significant   |
  
+-+---+-+--+---+
  | html5lib| 137 ms| 135 ms  | 1.01x faster | 
Not significant   |
  
+-+---+-+--+---+
  | json_dumps  | 18.8 ms   | 17.9 ms | 1.05x faster | 
Significant (t=4.81)  |
  
+-+---+-+--+---+
  | json_loads  | 41.3 us   | 40.2 us | 1.03x faster | 
Significant (t=2.53)  |
  
+-+---+-+--+---+
  | logging_format  | 17.4 us   | 17.5 us | 1.00x slower | 
Not significant   |
  
+-+---+-+--+---+
  | logging_silent  | 509 ns| 500 ns  | 1.02x faster | 
Not significant   |
  
+-+---+-+--+---+
  | logging_simple  | 14.3 us   | 14.8 us | 

[PATCH] D68720: Support -fstack-clash-protection for x86

[Reid Kleckner via Phabricator via cfe-commits]

rnk added a comment.

For maintenance reasons, I'd really prefer it if we could find a way to reuse 
the existing code that calls an external stack probe function. What do you 
think about taking a look at X86RetpolineThunks.cpp and doing something similar 
to that? Basically, when the user sets `-fstack-clash-protection`, LLVM will 
emit a small comdat+weak function into every object file that has the same ABI 
as the existing stack probe mechanism. For other prior art, you can also look 
at how `__clang_call_terminate` works.




Comment at: llvm/lib/Target/X86/X86FrameLowering.cpp:400
+!(STI.isOSWindows() && !STI.isTargetMachO());
+if (InlineStackClashProtector && !InEpilogue) {
+  const uint64_t PageSize = TLI.getStackProbeSize(MF);

serge-sans-paille wrote:
> efriedma wrote:
> > Why is this code in a different location from the stack probing code that 
> > generates a call?
> Because `BuildStackAdjustment` has more callsites than just emitPrologue and 
> we want to capture all stack manipulation.
If you care about those cases, we should have tests for all of them. These are 
all the cases:
1. TailCallReturnAddrDelta: When doing guaranteed TCO for a callee with >4K of 
argument memory
2. eliminateCallFramePseudoInstr: When doing stack adjustments to set up a call 
with more than 4K of arguments

Both of these cases involve setting up arguments to calls, and I think we can 
guarantee that the compiler will emit writes to every argument stack slot. So, 
to set up one of these cases, we'd have this code:
```
struct EightK { int a[2048]; };
void passEightK(EightK);
void foo() {
  EightK x;
  memset(, 0, sizeof(x));
  passEightK(x); // some targets will pass indirect, 32-bit probably uses byval.
}
```

In this case, LLVM happens to use rep;movsl to copy the argument memory. It 
could use memcpy, but either way, it will probe all those bytes.

I think that means it's safe to move to emitSPUpdate. I would greatly prefer 
that `BuildStackAdjustment` remain a simple primitive that generates a single 
instruction.



Comment at: llvm/lib/Target/X86/X86FrameLowering.cpp:353
 
+static const DenseMap OpcodeToSPOperandIndex = {
+{X86::MOV8mi, 3}, {X86::MOV16mi, 3}, {X86::MOV32mi, 3}, {X86::MOV64mi32, 
3},

Please no dynamically initialized globals. The LLVM-y thing would be to use a 
switch.



Comment at: llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll:9-11
+; CHECK: subq   $4096, %rsp
+; CHECK: movq   $0, (%rsp)
+  %a = alloca i32, i32 %n, align 16

This seems like a good use case for update_llc_test_checks.py. I'd want to see 
the body of the loop, the cmp, the jl, etc.


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[PATCH] D68720: Support -fstack-clash-protection for x86

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serge-sans-paille updated this revision to Diff 224606.
serge-sans-paille added a comment.

Ensure the distance between two probes is at max PAGE_SIZE.
Use Calls as free probes.
Fix alignment for dynamic alloca

This passes the llvm-test suite, and thanks to the use of calls, no inserted 
probe are needed to compile sqlite!


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Files:
  clang/docs/ReleaseNotes.rst
  clang/include/clang/Basic/CodeGenOptions.def
  clang/include/clang/Basic/DiagnosticFrontendKinds.td
  clang/include/clang/Basic/TargetInfo.h
  clang/include/clang/Driver/CC1Options.td
  clang/include/clang/Driver/Options.td
  clang/lib/Basic/Targets/X86.h
  clang/lib/CodeGen/CGStmt.cpp
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/test/CodeGen/stack-clash-protection.c
  clang/test/Driver/stack-clash-protection.c
  llvm/docs/ReleaseNotes.rst
  llvm/include/llvm/CodeGen/TargetLowering.h
  llvm/lib/Target/X86/X86CallFrameOptimization.cpp
  llvm/lib/Target/X86/X86FrameLowering.cpp
  llvm/lib/Target/X86/X86FrameLowering.h
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/lib/Target/X86/X86ISelLowering.h
  llvm/lib/Target/X86/X86InstrCompiler.td
  llvm/lib/Target/X86/X86InstrInfo.td
  llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
  llvm/test/CodeGen/X86/stack-clash-medium.ll
  llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
  llvm/test/CodeGen/X86/stack-clash-small.ll

Index: llvm/test/CodeGen/X86/stack-clash-small.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-small.ll
@@ -0,0 +1,19 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK-LABEL: foo:
+define i32 @foo() local_unnamed_addr #0 {
+; only one stack growth
+; CHECK: subq
+; CHECK-NOT: subq
+  %a = alloca i32, i64 100, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 98
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
@@ -0,0 +1,20 @@
+; RUN: llc < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK-LABEL: foo:
+define i32 @foo(i64 %i) local_unnamed_addr #0 {
+; CHECK: subq   $4096, %rsp
+; the store location is not statically known, no free probe
+; CHECK: movq   $0, (%rsp)
+; CHECK: subq   ${{[0-9]+}}, %rsp
+  %a = alloca i32, i32 2000, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 %i
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
+
Index: llvm/test/CodeGen/X86/stack-clash-medium.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-medium.ll
@@ -0,0 +1,21 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK-LABEL: foo:
+define i32 @foo() local_unnamed_addr #0 {
+; two stack growth, with a natural probe inbetween and an extra probe afterward
+; CHECK: subq
+; CHECK: movl
+; CHECK: subq
+; CHECK: movq $0
+  %a = alloca i32, i64 2000, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 1198
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
@@ -0,0 +1,25 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK-LABEL: foo:
+define i32 @foo() local_unnamed_addr #0 {
+; two stack growth, with an extra probe inbetween and a natural probe afterward
+; CHECK: subq
+; CHECK-NOT: movq $0
+; CHECK: mov
+; CHECK: subq
+; CHECK-NOT: movq $0
+; CHECK: mov
+  %a = alloca i32, i64 2000, align 16
+  %b0 = getelementptr inbounds i32, i32* %a, i64 98
+  %b1 = getelementptr inbounds i32, i32* %a, i64 1198
+  store volatile i32 1, i32* %b0
+  store volatile i32 1, i32* %b1
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
===
--- /dev/null
+++ 

[PATCH] D68720: Support -fstack-clash-protection for x86

[Tom Stellard via Phabricator via cfe-commits]

tstellar added inline comments.



Comment at: clang/test/CodeGen/stack-clash-protection.c:3
+// RUN: %clang -target x86_64 -o %t.out %s -fstack-clash-protection && %t.out
+
+#include 

There were concerns[1] raised recently about adding clang tests that were 
codegen dependent.  Is something being tested here that can't be tested with an 
IR test?  If you only need to test that the frontend option work, I think 
checking the IR for the necessary function attributes might be enough.



[1] http://lists.llvm.org/pipermail/cfe-dev/2019-September/063309.html


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[PATCH] D68720: Support -fstack-clash-protection for x86

[Eli Friedman via Phabricator via cfe-commits]

efriedma added inline comments.



Comment at: llvm/lib/Target/X86/X86FrameLowering.cpp:423
+   AbsOffset - CurrentAbsOffset + PageSize);
+if (FreeProbeIterator != MBB.end()) {
+  NumFrameFreeProbe++;

Each probe has to have an offset of at most PageSize bytes from the previous 
probe.  If each probe is exactly PageSize bytes away from the previous probe, 
that's fine.  But it looks like you don't enforce the distance between free 
probes correctly?



Comment at: llvm/lib/Target/X86/X86FrameLowering.cpp:481
+[](MachineOperand ) { return MO.isFI(); })) {
+  break; // effect on stack pointer not modelled, stopping
+}

There are instructions that don't refer to any FI, but are still relevant.  For 
example, calls.


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[PATCH] D68720: Support -fstack-clash-protection for x86

[Dávid Bolvanský via Phabricator via cfe-commits]

xbolva00 added inline comments.



Comment at: llvm/lib/Target/X86/X86FrameLowering.cpp:479
+}
+if (std::any_of(MI.operands_begin(), MI.operands_end(),
+[](MachineOperand ) { return MO.isFI(); })) {

nit: llvm::any_of


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[PATCH] D68720: Support -fstack-clash-protection for x86

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serge-sans-paille added a comment.

Some early stats: on the sqlite amalgamation [0], the free probe reuse  allows 
to skip 123 out of the 474 probes needed during frame lowering.

[0] https://www.sqlite.org/download.html


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[PATCH] D68720: Support -fstack-clash-protection for x86

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serge-sans-paille updated this revision to Diff 224431.
serge-sans-paille edited the summary of this revision.
serge-sans-paille added a comment.

Added test case, statistics and refactor interactions with existing stack 
probing mechanism.


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Files:
  clang/docs/ReleaseNotes.rst
  clang/include/clang/Basic/CodeGenOptions.def
  clang/include/clang/Basic/DiagnosticFrontendKinds.td
  clang/include/clang/Basic/TargetInfo.h
  clang/include/clang/Driver/CC1Options.td
  clang/include/clang/Driver/Options.td
  clang/lib/Basic/Targets/X86.h
  clang/lib/CodeGen/CGStmt.cpp
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/test/CodeGen/stack-clash-protection.c
  clang/test/Driver/stack-clash-protection.c
  llvm/docs/ReleaseNotes.rst
  llvm/include/llvm/CodeGen/TargetLowering.h
  llvm/lib/Target/X86/X86CallFrameOptimization.cpp
  llvm/lib/Target/X86/X86FrameLowering.cpp
  llvm/lib/Target/X86/X86FrameLowering.h
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/lib/Target/X86/X86ISelLowering.h
  llvm/lib/Target/X86/X86InstrCompiler.td
  llvm/lib/Target/X86/X86InstrInfo.td
  llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
  llvm/test/CodeGen/X86/stack-clash-medium.ll
  llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
  llvm/test/CodeGen/X86/stack-clash-small.ll

Index: llvm/test/CodeGen/X86/stack-clash-small.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-small.ll
@@ -0,0 +1,19 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK-LABEL: foo:
+define i32 @foo() local_unnamed_addr #0 {
+; only one stack growth
+; CHECK: subq
+; CHECK-NOT: subq
+  %a = alloca i32, i64 100, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 98
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
@@ -0,0 +1,20 @@
+; RUN: llc < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK-LABEL: foo:
+define i32 @foo(i64 %i) local_unnamed_addr #0 {
+; CHECK: subq   $4096, %rsp
+; the store location is not statically known, no free probe
+; CHECK: movq   $0, (%rsp)
+; CHECK: subq   ${{[0-9]+}}, %rsp
+  %a = alloca i32, i32 2000, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 %i
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
+
Index: llvm/test/CodeGen/X86/stack-clash-medium.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-medium.ll
@@ -0,0 +1,21 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK-LABEL: foo:
+define i32 @foo() local_unnamed_addr #0 {
+; two stack growth, with a natural probe inbetween and an extra probe afterward
+; CHECK: subq
+; CHECK: movl
+; CHECK: subq
+; CHECK: movq $0
+  %a = alloca i32, i64 2000, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 1198
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
@@ -0,0 +1,25 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK-LABEL: foo:
+define i32 @foo() local_unnamed_addr #0 {
+; two stack growth, with an extra probe inbetween and a natural probe afterward
+; CHECK: subq
+; CHECK-NOT: movq $0
+; CHECK: mov
+; CHECK: subq
+; CHECK-NOT: movq $0
+; CHECK: mov
+  %a = alloca i32, i64 2000, align 16
+  %b0 = getelementptr inbounds i32, i32* %a, i64 98
+  %b1 = getelementptr inbounds i32, i32* %a, i64 1198
+  store volatile i32 1, i32* %b0
+  store volatile i32 1, i32* %b1
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
@@ -0,0 +1,18 @@
+; RUN: llc < %s | FileCheck %s
+

[PATCH] D68720: Support -fstack-clash-protection for x86

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serge-sans-paille marked 3 inline comments as done.
serge-sans-paille added inline comments.



Comment at: llvm/lib/Target/X86/X86FrameLowering.cpp:400
+!(STI.isOSWindows() && !STI.isTargetMachO());
+if (InlineStackClashProtector && !InEpilogue) {
+  const uint64_t PageSize = TLI.getStackProbeSize(MF);

efriedma wrote:
> Why is this code in a different location from the stack probing code that 
> generates a call?
Because `BuildStackAdjustment` has more callsites than just emitPrologue and we 
want to capture all stack manipulation.



Comment at: llvm/lib/Target/X86/X86FrameLowering.cpp:408
+CurrentAbsOffset += ChunkSize;
+MI->getOperand(3).setIsDead(); // The EFLAGS implicit def is dead.
+

efriedma wrote:
> This algorithm needs some documentation; it isn't at all obvious what it's 
> doing.  Particularly the interaction with "free" stack probes.
> 
> Should we generate a loop if the stack frame is large?
> Should we generate a loop if the stack frame is large?

That's an option. it's more complex to make looping compatible with free 
probes, but that's possible.



Comment at: llvm/lib/Target/X86/X86FrameLowering.cpp:408
+CurrentAbsOffset += ChunkSize;
+MI->getOperand(3).setIsDead(); // The EFLAGS implicit def is dead.
+

serge-sans-paille wrote:
> efriedma wrote:
> > This algorithm needs some documentation; it isn't at all obvious what it's 
> > doing.  Particularly the interaction with "free" stack probes.
> > 
> > Should we generate a loop if the stack frame is large?
> > Should we generate a loop if the stack frame is large?
> 
> That's an option. it's more complex to make looping compatible with free 
> probes, but that's possible.
> This algorithm needs some documentation
Done


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[PATCH] D68720: Support -fstack-clash-protection for x86

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serge-sans-paille added a subscriber: eli.friedman.
serge-sans-paille added a comment.

@efriedma  the free probe algorithm requires more testing, and I'd like to take 
into account memset and memcpy as free probes too. To showcase this algorithm, 
consider the following LLVM bitcode:

  define i32 @foo() local_unnamed_addr {
%a = alloca i32, i64 2000, align 16
%b = getelementptr inbounds i32, i32* %a, i64 1198
store volatile i32 1, i32* %b
%c = load volatile i32, i32* %a
ret i32 %c
  }

when compiled with `llc` it outputs the following assembly:

  foo:# @foo
  subq$7880, %rsp # imm = 0x1EC8
  movl$1, 4664(%rsp)
  movl-128(%rsp), %eax
  addq$7880, %rsp # imm = 0x1EC8
  retq

When `probe-stack` is set to `inline-asm` it outputs

  foo:# @foo
subq$4096, %rsp # imm = 0x1000
movl$1, 880(%rsp)
subq$3784, %rsp # imm = 0xEC8
movq$0, (%rsp)
movl-128(%rsp), %eax
addq$7880, %rsp # imm = 0x1EC8
retq

The stack allocation is split in two, but only one MOV is added, the first one 
is what I call a free probe. Turns out we could only use natural probes here, I 
need to implement that :-)

As a comparison, setting `probe-stack` to a random function name like 
`__probe_stack` outputs the following:

  foo:# @foo
movl$8008, %eax # imm = 0x1F48
callq   __probe_stack
subq%rax, %rsp
movl$1, 4792(%rsp)
movl(%rsp), %eax
addq$8008, %rsp # imm = 0x1F48
retq

which requires runtime support (to provide `__stack_probe`), and a function 
call overhead, while ideally just an extra `sub %rsp` would be needed.


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[PATCH] D68720: Support -fstack-clash-protection for x86

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serge-sans-paille updated this revision to Diff 224254.
serge-sans-paille added a comment.

Added documentation + release note entry


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Files:
  clang/docs/ReleaseNotes.rst
  clang/include/clang/Basic/CodeGenOptions.def
  clang/include/clang/Basic/DiagnosticFrontendKinds.td
  clang/include/clang/Basic/TargetInfo.h
  clang/include/clang/Driver/CC1Options.td
  clang/include/clang/Driver/Options.td
  clang/lib/Basic/Targets/X86.h
  clang/lib/CodeGen/CGStmt.cpp
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/test/CodeGen/stack-clash-protection.c
  clang/test/Driver/stack-clash-protection.c
  llvm/docs/ReleaseNotes.rst
  llvm/lib/Target/X86/X86FrameLowering.cpp
  llvm/lib/Target/X86/X86FrameLowering.h
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/lib/Target/X86/X86ISelLowering.h
  llvm/lib/Target/X86/X86InstrCompiler.td
  llvm/lib/Target/X86/X86InstrInfo.td
  llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
  llvm/test/CodeGen/X86/stack-clash-medium.ll
  llvm/test/CodeGen/X86/stack-clash-small.ll

Index: llvm/test/CodeGen/X86/stack-clash-small.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-small.ll
@@ -0,0 +1,19 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK-LABEL: foo:
+define i32 @foo() local_unnamed_addr #0 {
+; only one stack growth
+; CHECK: subq
+; CHECK-NOT: subq
+  %a = alloca i32, i64 100, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 98
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-medium.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-medium.ll
@@ -0,0 +1,21 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK-LABEL: foo:
+define i32 @foo() local_unnamed_addr #0 {
+; two stack growth, with a natural probe inbetween and an extra probe afterward
+; CHECK: subq
+; CHECK: movl
+; CHECK: subq
+; CHECK: movq $0
+  %a = alloca i32, i64 2000, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 1198
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
@@ -0,0 +1,25 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK-LABEL: foo:
+define i32 @foo() local_unnamed_addr #0 {
+; two stack growth, with an extra probe inbetween and a natural probe afterward
+; CHECK: subq
+; CHECK-NOT: movq $0
+; CHECK: mov
+; CHECK: subq
+; CHECK-NOT: movq $0
+; CHECK: mov
+  %a = alloca i32, i64 2000, align 16
+  %b0 = getelementptr inbounds i32, i32* %a, i64 98
+  %b1 = getelementptr inbounds i32, i32* %a, i64 1198
+  store volatile i32 1, i32* %b0
+  store volatile i32 1, i32* %b1
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
@@ -0,0 +1,18 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK-LABEL: foo:
+define i32 @foo(i32 %n) local_unnamed_addr #0 {
+; CHECK: subq   $4096, %rsp
+; CHECK: movq   $0, (%rsp)
+  %a = alloca i32, i32 %n, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 1198
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/lib/Target/X86/X86InstrInfo.td
===
--- llvm/lib/Target/X86/X86InstrInfo.td
+++ llvm/lib/Target/X86/X86InstrInfo.td
@@ -121,6 +121,8 @@
 
 def SDT_X86SEG_ALLOCA : SDTypeProfile<1, 1, [SDTCisVT<0, iPTR>, SDTCisVT<1, iPTR>]>;
 
+def SDT_X86PROBED_ALLOCA : SDTypeProfile<1, 1, [SDTCisVT<0, iPTR>, SDTCisVT<1, iPTR>]>;
+
 def SDT_X86EHRET : SDTypeProfile<0, 1, [SDTCisInt<0>]>;
 
 def SDT_X86TCRET : SDTypeProfile<0, 2, [SDTCisPtrTy<0>, SDTCisVT<1, i32>]>;
@@ -292,6 +294,9 @@
 def X86SegAlloca : SDNode<"X86ISD::SEG_ALLOCA", 

[PATCH] D68720: Support -fstack-clash-protection for x86

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xbolva00 added a comment.

Please add info about this new feature to release notes


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[PATCH] D68720: Support -fstack-clash-protection for x86

[Eli Friedman via Phabricator via cfe-commits]

efriedma added a comment.

> (b) is an issue, as pointed out in https://lwn.net/Articles/726587/ (grep for 
> valgrind) : from valgrind point of view, accessing un-allocated stack memory 
> triggers error, and we probably want to please valgrind
> 
> Doing the call *after* the stack allocation is also not an option, as a 
> signal could be raised between the stack allocation and the stack probing, 
> escaping the stack probe if a custom signal handler is executed.

I'm not sure I follow.  How are you solving this problem in your patch?  By 
limiting the amount you adjust the stack at a time?  What limit is sufficient 
to avoid this issue?

-

Can you give a complete assembly listing for small examples of static and 
dynamic stack probing?




Comment at: llvm/lib/Target/X86/X86FrameLowering.cpp:400
+!(STI.isOSWindows() && !STI.isTargetMachO());
+if (InlineStackClashProtector && !InEpilogue) {
+  const uint64_t PageSize = TLI.getStackProbeSize(MF);

Why is this code in a different location from the stack probing code that 
generates a call?



Comment at: llvm/lib/Target/X86/X86FrameLowering.cpp:408
+CurrentAbsOffset += ChunkSize;
+MI->getOperand(3).setIsDead(); // The EFLAGS implicit def is dead.
+

This algorithm needs some documentation; it isn't at all obvious what it's 
doing.  Particularly the interaction with "free" stack probes.

Should we generate a loop if the stack frame is large?


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serge-sans-paille added a comment.

@efriedma alos compared to `probe-stack` with a function, this version has the 
ability to use existing MOV operations to avoid generating probes, which looks 
like a big plus to me.


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[PATCH] D68720: Support -fstack-clash-protection for x86

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serge-sans-paille updated this revision to Diff 224196.
serge-sans-paille added a comment.

Move to `stack-probe` compatibility, using a dedicated name to trigger inline 
assembly. It looks better to me because

1. it leverage existing mechanics
2. it has a finer grain


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Files:
  clang/include/clang/Basic/CodeGenOptions.def
  clang/include/clang/Basic/DiagnosticFrontendKinds.td
  clang/include/clang/Basic/TargetInfo.h
  clang/include/clang/Driver/CC1Options.td
  clang/include/clang/Driver/Options.td
  clang/lib/Basic/Targets/X86.h
  clang/lib/CodeGen/CGStmt.cpp
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/test/CodeGen/stack-clash-protection.c
  clang/test/Driver/stack-clash-protection.c
  llvm/lib/Target/X86/X86FrameLowering.cpp
  llvm/lib/Target/X86/X86FrameLowering.h
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/lib/Target/X86/X86ISelLowering.h
  llvm/lib/Target/X86/X86InstrCompiler.td
  llvm/lib/Target/X86/X86InstrInfo.td
  llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
  llvm/test/CodeGen/X86/stack-clash-medium.ll
  llvm/test/CodeGen/X86/stack-clash-small.ll

Index: llvm/test/CodeGen/X86/stack-clash-small.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-small.ll
@@ -0,0 +1,19 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK-LABEL: foo:
+define i32 @foo() local_unnamed_addr #0 {
+; only one stack growth
+; CHECK: subq
+; CHECK-NOT: subq
+  %a = alloca i32, i64 100, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 98
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-medium.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-medium.ll
@@ -0,0 +1,21 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK-LABEL: foo:
+define i32 @foo() local_unnamed_addr #0 {
+; two stack growth, with a natural probe inbetween and an extra probe afterward
+; CHECK: subq
+; CHECK: movl
+; CHECK: subq
+; CHECK: movq $0
+  %a = alloca i32, i64 2000, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 1198
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
@@ -0,0 +1,25 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK-LABEL: foo:
+define i32 @foo() local_unnamed_addr #0 {
+; two stack growth, with an extra probe inbetween and a natural probe afterward
+; CHECK: subq
+; CHECK-NOT: movq $0
+; CHECK: mov
+; CHECK: subq
+; CHECK-NOT: movq $0
+; CHECK: mov
+  %a = alloca i32, i64 2000, align 16
+  %b0 = getelementptr inbounds i32, i32* %a, i64 98
+  %b1 = getelementptr inbounds i32, i32* %a, i64 1198
+  store volatile i32 1, i32* %b0
+  store volatile i32 1, i32* %b1
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
@@ -0,0 +1,18 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK-LABEL: foo:
+define i32 @foo(i32 %n) local_unnamed_addr #0 {
+; CHECK: subq   $4096, %rsp
+; CHECK: movq   $0, (%rsp)
+  %a = alloca i32, i32 %n, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 1198
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
+
+attributes #0 =  {"probe-stack"="inline-asm"}
Index: llvm/lib/Target/X86/X86InstrInfo.td
===
--- llvm/lib/Target/X86/X86InstrInfo.td
+++ llvm/lib/Target/X86/X86InstrInfo.td
@@ -121,6 +121,8 @@
 
 def SDT_X86SEG_ALLOCA : SDTypeProfile<1, 1, [SDTCisVT<0, iPTR>, SDTCisVT<1, iPTR>]>;
 
+def SDT_X86PROBED_ALLOCA : SDTypeProfile<1, 1, [SDTCisVT<0, iPTR>, SDTCisVT<1, iPTR>]>;
+
 def SDT_X86EHRET : SDTypeProfile<0, 1, [SDTCisInt<0>]>;
 
 def SDT_X86TCRET : SDTypeProfile<0, 2, [SDTCisPtrTy<0>, SDTCisVT<1, 

[PATCH] D68720: Support -fstack-clash-protection for x86

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serge-sans-paille added a comment.

@efriedma : there's indeed an intersection with the `probe-stack` attribute. 
The `probe-stack` attribute (a) forces a function call, and (b) this function 
call only happens **before** the stack gets expanded.

(a) is probably a performance issue in several cases, plus it requires an extra 
register (that's mentioned in  https://reviews.llvm.org/D9653) 
(b) is an issue, as pointed out in https://lwn.net/Articles/726587/ (grep for 
valgrind)  : from valgrind point of view, accessing un-allocated stack memory 
triggers error, and we probably want to please valgrind

Doing the call *after* the stack allocation is also not an option, as a signal 
could be raised between the stack allocation and the stack probing, escaping 
the stack probe if a custom signal handler is executed.

That being said, I do think it would be a good thing to have a special value 
for `probe-stack`, say `probe-stack=inline-asm`, that would trigger generation 
of inlined assembly as I do. That way we have all the pieces in one place, with 
different strategies. And we would have clang set the attribute for each 
function when `-fstack-clash-protection` is given.


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[PATCH] D68720: Support -fstack-clash-protection for x86

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efriedma added a comment.

Sorry, I meant the "probe-stack" attribute.


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[PATCH] D68720: Support -fstack-clash-protection for x86

[Eli Friedman via Phabricator via cfe-commits]

efriedma added a comment.

Is there some reason this isn't using the existing stack-probe-size attribute?


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[PATCH] D68720: Support -fstack-clash-protection for x86

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serge-sans-paille created this revision.
Herald added subscribers: llvm-commits, cfe-commits, hiraditya, dschuff.
Herald added projects: clang, LLVM.

Implement protection against the stack clash attack [0].

Probe stack allocation every PAGE_SIZE during frame lowering or dynamic 
allocation to make sure the  page guard, if any, is touched when touching the 
stack, in a similar manner to GCC[1].

If possible, use MOV already present in the entry block instead of generating 
new ones.

Only implemented for x86.

[0] https://www.qualys.com/2017/06/19/stack-clash/stack-clash.txt
[1] https://gcc.gnu.org/ml/gcc-patches/2017-07/msg00556.html


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D68720

Files:
  clang/include/clang/Basic/CodeGenOptions.def
  clang/include/clang/Basic/DiagnosticFrontendKinds.td
  clang/include/clang/Basic/TargetInfo.h
  clang/include/clang/Driver/CC1Options.td
  clang/include/clang/Driver/Options.td
  clang/lib/Basic/Targets/X86.h
  clang/lib/CodeGen/BackendUtil.cpp
  clang/lib/CodeGen/CGStmt.cpp
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/test/CodeGen/stack-clash-protection.c
  clang/test/Driver/stack-clash-protection.c
  llvm/include/llvm/CodeGen/CommandFlags.inc
  llvm/include/llvm/Target/TargetOptions.h
  llvm/lib/Target/X86/X86FrameLowering.cpp
  llvm/lib/Target/X86/X86FrameLowering.h
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/lib/Target/X86/X86ISelLowering.h
  llvm/lib/Target/X86/X86InstrCompiler.td
  llvm/lib/Target/X86/X86InstrInfo.td
  llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
  llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
  llvm/test/CodeGen/X86/stack-clash-medium.ll
  llvm/test/CodeGen/X86/stack-clash-small.ll

Index: llvm/test/CodeGen/X86/stack-clash-small.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-small.ll
@@ -0,0 +1,17 @@
+; RUN: llc --stack-clash-protector < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK-LABEL: foo:
+define i32 @foo() local_unnamed_addr {
+; only one stack growth
+; CHECK: subq
+; CHECK-NOT: subq
+  %a = alloca i32, i64 100, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 98
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
Index: llvm/test/CodeGen/X86/stack-clash-medium.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-medium.ll
@@ -0,0 +1,19 @@
+; RUN: llc --stack-clash-protector < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK-LABEL: foo:
+define i32 @foo() local_unnamed_addr {
+; two stack growth, with a natural probe inbetween and an extra probe afterward
+; CHECK: subq
+; CHECK: movl
+; CHECK: subq
+; CHECK: movq $0
+  %a = alloca i32, i64 2000, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 1198
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
Index: llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-medium-natural-probes.ll
@@ -0,0 +1,23 @@
+; RUN: llc --stack-clash-protector < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK-LABEL: foo:
+define i32 @foo() local_unnamed_addr {
+; two stack growth, with an extra probe inbetween and a natural probe afterward
+; CHECK: subq
+; CHECK-NOT: movq $0
+; CHECK: mov
+; CHECK: subq
+; CHECK-NOT: movq $0
+; CHECK: mov
+  %a = alloca i32, i64 2000, align 16
+  %b0 = getelementptr inbounds i32, i32* %a, i64 98
+  %b1 = getelementptr inbounds i32, i32* %a, i64 1198
+  store volatile i32 1, i32* %b0
+  store volatile i32 1, i32* %b1
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
Index: llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/stack-clash-dynamic-alloca.ll
@@ -0,0 +1,16 @@
+; RUN: llc --stack-clash-protector < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK-LABEL: foo:
+define i32 @foo(i32 %n) local_unnamed_addr {
+; CHECK: subq   $4096, %rsp
+; CHECK: movq   $0, (%rsp)
+  %a = alloca i32, i32 %n, align 16
+  %b = getelementptr inbounds i32, i32* %a, i64 1198
+  store volatile i32 1, i32* %b
+  %c = load volatile i32, i32* %a
+  ret i32 %c
+}
Index: llvm/lib/Target/X86/X86InstrInfo.td
===
--- llvm/lib/Target/X86/X86InstrInfo.td
+++ llvm/lib/Target/X86/X86InstrInfo.td
@@ -121,6 +121,8 @@
 
 def SDT_X86SEG_ALLOCA :