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aganea marked 3 inline comments as done.
Closed by commit rG5af2433e1794: [clang-cl] Support the /HOTPATCH flag
(authored by aganea).
Changed prior to commit:
https://reviews.llvm.org/D116511?vs=399168&id=401678#toc
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D116511/new/
https://reviews.llvm.org/D116511
Files:
clang/docs/ReleaseNotes.rst
clang/include/clang/Basic/CodeGenOptions.def
clang/include/clang/Driver/Options.td
clang/lib/CodeGen/BackendUtil.cpp
clang/lib/CodeGen/CodeGenFunction.cpp
clang/lib/Driver/ToolChains/Clang.cpp
clang/lib/Driver/ToolChains/MSVC.cpp
clang/test/CodeGen/patchable-function-entry.c
clang/test/CodeGenCXX/debug-info-hotpatch-arm.cpp
clang/test/CodeGenCXX/debug-info-hotpatch.cpp
clang/test/Driver/cl-options.c
llvm/include/llvm/Target/TargetOptions.h
llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
llvm/test/DebugInfo/COFF/ARMNT/arm-register-variables.ll
llvm/test/MC/AArch64/coff-debug.ll
Index: llvm/test/MC/AArch64/coff-debug.ll
===================================================================
--- llvm/test/MC/AArch64/coff-debug.ll
+++ llvm/test/MC/AArch64/coff-debug.ll
@@ -77,7 +77,8 @@
; CHECK: Compile3Sym {
; CHECK: Kind: S_COMPILE3 (0x113C)
; CHECK: Language: C (0x0)
-; CHECK: Flags [ (0x0)
+; CHECK: Flags [ (0x4000
+; CHECK: HotPatch (0x4000)
; CHECK: ]
; CHECK: }
; CHECK: ]
Index: llvm/test/DebugInfo/COFF/ARMNT/arm-register-variables.ll
===================================================================
--- llvm/test/DebugInfo/COFF/ARMNT/arm-register-variables.ll
+++ llvm/test/DebugInfo/COFF/ARMNT/arm-register-variables.ll
@@ -24,7 +24,8 @@
; OBJ: Compile3Sym {
; OBJ-NEXT: Kind: S_COMPILE3 (0x113C)
; OBJ-NEXT: Language: C (0x0)
-; OBJ-NEXT: Flags [ (0x0)
+; OBJ-NEXT: Flags [ (0x4000)
+; OBJ-NEXT: HotPatch (0x4000)
; OBJ-NEXT: ]
; OBJ-NEXT: Machine: ARMNT (0xF4)
Index: llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
===================================================================
--- llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
+++ llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
@@ -846,6 +846,12 @@
if (MMI->getModule()->getProfileSummary(/*IsCS*/ false) != nullptr) {
Flags |= static_cast<uint32_t>(CompileSym3Flags::PGO);
}
+ using ArchType = llvm::Triple::ArchType;
+ ArchType Arch = Triple(MMI->getModule()->getTargetTriple()).getArch();
+ if (Asm->TM.Options.Hotpatch || Arch == ArchType::thumb ||
+ Arch == ArchType::aarch64) {
+ Flags |= static_cast<uint32_t>(CompileSym3Flags::HotPatch);
+ }
OS.AddComment("Flags and language");
OS.emitInt32(Flags);
Index: llvm/include/llvm/Target/TargetOptions.h
===================================================================
--- llvm/include/llvm/Target/TargetOptions.h
+++ llvm/include/llvm/Target/TargetOptions.h
@@ -140,9 +140,9 @@
EnableMachineFunctionSplitter(false), SupportsDefaultOutlining(false),
EmitAddrsig(false), EmitCallSiteInfo(false),
SupportsDebugEntryValues(false), EnableDebugEntryValues(false),
- ValueTrackingVariableLocations(false),
- ForceDwarfFrameSection(false), XRayOmitFunctionIndex(false),
- DebugStrictDwarf(false),
+ ValueTrackingVariableLocations(false), ForceDwarfFrameSection(false),
+ XRayOmitFunctionIndex(false), DebugStrictDwarf(false),
+ Hotpatch(false),
FPDenormalMode(DenormalMode::IEEE, DenormalMode::IEEE) {}
/// DisableFramePointerElim - This returns true if frame pointer elimination
@@ -342,6 +342,9 @@
/// By default, it is set to false.
unsigned DebugStrictDwarf : 1;
+ /// Emit the hotpatch flag in CodeView debug.
+ unsigned Hotpatch : 1;
+
/// Name of the stack usage file (i.e., .su file) if user passes
/// -fstack-usage. If empty, it can be implied that -fstack-usage is not
/// passed on the command line.
Index: clang/test/Driver/cl-options.c
===================================================================
--- clang/test/Driver/cl-options.c
+++ clang/test/Driver/cl-options.c
@@ -118,6 +118,9 @@
// RUN: %clang_cl /Gw /Gw- -### -- %s 2>&1 | FileCheck -check-prefix=Gw_ %s
// Gw_-NOT: -fdata-sections
+// RUN: %clang_cl /hotpatch -### -- %s 2>&1 | FileCheck -check-prefix=hotpatch %s
+// hotpatch: -fms-hotpatch
+
// RUN: %clang_cl /Imyincludedir -### -- %s 2>&1 | FileCheck -check-prefix=SLASH_I %s
// RUN: %clang_cl /I myincludedir -### -- %s 2>&1 | FileCheck -check-prefix=SLASH_I %s
// SLASH_I: "-I" "myincludedir"
@@ -483,7 +486,6 @@
// RUN: /GZ \
// RUN: /H \
// RUN: /homeparams \
-// RUN: /hotpatch \
// RUN: /JMC \
// RUN: /kernel \
// RUN: /LN \
Index: clang/test/CodeGenCXX/debug-info-hotpatch.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGenCXX/debug-info-hotpatch.cpp
@@ -0,0 +1,20 @@
+// REQUIRES: x86-registered-target
+///
+// RUN: %clang_cl --target=x86_64-windows-msvc /c /hotpatch /Z7 -o %t.obj -- %s
+// RUN: llvm-pdbutil dump -symbols %t.obj | FileCheck %s --check-prefix=HOTPATCH
+// HOTPATCH: S_COMPILE3 [size = [[#]]]
+// HOTPATCH: flags = hot patchable
+///
+// RUN: %clang_cl --target=x86_64-windows-msvc /c /Z7 -o %t.obj -- %s
+// RUN: llvm-pdbutil dump -symbols %t.obj | FileCheck %s --check-prefix=NO-HOTPATCH
+// NO-HOTPATCH-NOT: flags = hot patchable
+///
+// RUN: %clang_cl --target=x86_64-windows-msvc /hotpatch -### -- %s 2>&1 \
+// RUN: | FileCheck %s --check-prefix=FUNCTIONPADMIN
+// FUNCTIONPADMIN: clang{{.*}}
+// FUNCTIONPADMIN: {{link.*"}}
+// FUNCTIONPADMIN: -functionpadmin
+
+int main() {
+ return 0;
+}
Index: clang/test/CodeGenCXX/debug-info-hotpatch-arm.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGenCXX/debug-info-hotpatch-arm.cpp
@@ -0,0 +1,26 @@
+// REQUIRES: aarch64-registered-target || arm-registered-target
+///
+/// Check that using /hotpatch doesn't generate an error.
+/// Binaries are always hotpatchable on ARM/ARM64.
+///
+// RUN: %clang_cl --target=arm-pc-windows-msvc /c /hotpatch /Z7 -- %s 2>&1
+// RUN: %clang_cl --target=aarch64-pc-windows-msvc /c /hotpatch /Z7 -- %s 2>&1
+///
+/// Ensure that we set the hotpatchable flag in the debug information.
+///
+// RUN: %clang_cl --target=arm-pc-windows-msvc /c /Z7 -o %t.obj -- %s
+// RUN: llvm-pdbutil dump -symbols %t.obj | FileCheck %s --check-prefix=HOTPATCH
+// RUN: %clang_cl --target=aarch64-pc-windows-msvc /c /Z7 -o %t.obj -- %s
+// RUN: llvm-pdbutil dump -symbols %t.obj | FileCheck %s --check-prefix=HOTPATCH
+// HOTPATCH: S_COMPILE3 [size = [[#]]]
+// HOTPATCH: flags = hot patchable
+///
+/// Unfortunately we need /Z7, Clang does not systematically generate S_COMPILE3.
+///
+// RUN: %clang_cl --target=aarch64-pc-windows-msvc /c -o %t.obj -- %s
+// RUN: llvm-pdbutil dump -symbols %t.obj | FileCheck %s --check-prefix=NO-HOTPATCH
+// NO-HOTPATCH-NOT: flags = hot patchable
+
+int main() {
+ return 0;
+}
Index: clang/test/CodeGen/patchable-function-entry.c
===================================================================
--- clang/test/CodeGen/patchable-function-entry.c
+++ clang/test/CodeGen/patchable-function-entry.c
@@ -1,5 +1,6 @@
// RUN: %clang_cc1 -triple aarch64 -emit-llvm %s -o - | FileCheck %s
// RUN: %clang_cc1 -triple x86_64 -emit-llvm %s -fpatchable-function-entry=1 -o - | FileCheck --check-prefixes=CHECK,OPT %s
+// RUN: %clang_cc1 -triple x86_64 -emit-llvm %s -fms-hotpatch -o - | FileCheck --check-prefixes=HOTPATCH %s
// CHECK: define{{.*}} void @f0() #0
__attribute__((patchable_function_entry(0))) void f0() {}
@@ -34,3 +35,7 @@
// CHECK: attributes #2 = { {{.*}} "patchable-function-entry"="0" "patchable-function-prefix"="4"
// CHECK: attributes #3 = { {{.*}} "patchable-function-entry"="3" "patchable-function-prefix"="2"
// OPT: attributes #4 = { {{.*}} "patchable-function-entry"="1"
+// HOTPATCH: attributes #0 = { {{.*}} "patchable-function"="prologue-short-redirect"
+// HOTPATCH: attributes #1 = { {{.*}} "patchable-function"="prologue-short-redirect"
+// HOTPATCH: attributes #2 = { {{.*}} "patchable-function"="prologue-short-redirect"
+// HOTPATCH: attributes #3 = { {{.*}} "patchable-function"="prologue-short-redirect"
Index: clang/lib/Driver/ToolChains/MSVC.cpp
===================================================================
--- clang/lib/Driver/ToolChains/MSVC.cpp
+++ clang/lib/Driver/ToolChains/MSVC.cpp
@@ -511,6 +511,11 @@
if (Args.hasArg(options::OPT_g_Group, options::OPT__SLASH_Z7))
CmdArgs.push_back("-debug");
+ // If we specify /hotpatch, let the linker add padding in front of each
+ // function, like MSVC does.
+ if (Args.hasArg(options::OPT_fms_hotpatch, options::OPT__SLASH_hotpatch))
+ CmdArgs.push_back("-functionpadmin");
+
// Pass on /Brepro if it was passed to the compiler.
// Note that /Brepro maps to -mno-incremental-linker-compatible.
bool DefaultIncrementalLinkerCompatible =
Index: clang/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Clang.cpp
+++ clang/lib/Driver/ToolChains/Clang.cpp
@@ -6001,6 +6001,8 @@
}
}
+ Args.AddLastArg(CmdArgs, options::OPT_fms_hotpatch);
+
if (TC.SupportsProfiling()) {
Args.AddLastArg(CmdArgs, options::OPT_pg);
Index: clang/lib/CodeGen/CodeGenFunction.cpp
===================================================================
--- clang/lib/CodeGen/CodeGenFunction.cpp
+++ clang/lib/CodeGen/CodeGenFunction.cpp
@@ -882,6 +882,13 @@
if (Offset)
Fn->addFnAttr("patchable-function-prefix", std::to_string(Offset));
}
+ // Instruct that functions for COFF/CodeView targets should start with a
+ // patchable instruction, but only on x86/x64. Don't forward this to ARM/ARM64
+ // backends as they don't need it -- instructions on these architectures are
+ // always atomically patchable at runtime.
+ if (CGM.getCodeGenOpts().HotPatch &&
+ getContext().getTargetInfo().getTriple().isX86())
+ Fn->addFnAttr("patchable-function", "prologue-short-redirect");
// Add no-jump-tables value.
if (CGM.getCodeGenOpts().NoUseJumpTables)
Index: clang/lib/CodeGen/BackendUtil.cpp
===================================================================
--- clang/lib/CodeGen/BackendUtil.cpp
+++ clang/lib/CodeGen/BackendUtil.cpp
@@ -645,6 +645,7 @@
Options.MCOptions.CommandLineArgs = CodeGenOpts.CommandLineArgs;
Options.DebugStrictDwarf = CodeGenOpts.DebugStrictDwarf;
Options.ObjectFilenameForDebug = CodeGenOpts.ObjectFilenameForDebug;
+ Options.Hotpatch = CodeGenOpts.HotPatch;
return true;
}
Index: clang/include/clang/Driver/Options.td
===================================================================
--- clang/include/clang/Driver/Options.td
+++ clang/include/clang/Driver/Options.td
@@ -2498,6 +2498,9 @@
def fpatchable_function_entry_EQ : Joined<["-"], "fpatchable-function-entry=">, Group<f_Group>, Flags<[CC1Option]>,
MetaVarName<"<N,M>">, HelpText<"Generate M NOPs before function entry and N-M NOPs after function entry">,
MarshallingInfoInt<CodeGenOpts<"PatchableFunctionEntryCount">>;
+def fms_hotpatch : Flag<["-"], "fms-hotpatch">, Group<f_Group>, Flags<[CC1Option, CoreOption]>,
+ HelpText<"Ensure that all functions can be hotpatched at runtime">,
+ MarshallingInfoFlag<CodeGenOpts<"HotPatch">>;
def fpcc_struct_return : Flag<["-"], "fpcc-struct-return">, Group<f_Group>, Flags<[CC1Option]>,
HelpText<"Override the default ABI to return all structs on the stack">;
def fpch_preprocess : Flag<["-"], "fpch-preprocess">, Group<f_Group>;
@@ -6124,6 +6127,8 @@
def _SLASH_help : CLFlag<"help">, Alias<help>,
HelpText<"Display available options">;
def _SLASH_HELP : CLFlag<"HELP">, Alias<help>;
+def _SLASH_hotpatch : CLFlag<"hotpatch">, Alias<fms_hotpatch>,
+ HelpText<"Create hotpatchable image">;
def _SLASH_I : CLJoinedOrSeparate<"I">,
HelpText<"Add directory to include search path">, MetaVarName<"<dir>">,
Alias<I>;
@@ -6480,7 +6485,6 @@
def _SLASH_headerUnitAngle : CLJoinedOrSeparate<"headerUnit:angle">;
def _SLASH_headerUnitQuote : CLJoinedOrSeparate<"headerUnit:quote">;
def _SLASH_homeparams : CLFlag<"homeparams">;
-def _SLASH_hotpatch : CLFlag<"hotpatch">;
def _SLASH_kernel : CLFlag<"kernel">;
def _SLASH_LN : CLFlag<"LN">;
def _SLASH_MP : CLJoined<"MP">;
Index: clang/include/clang/Basic/CodeGenOptions.def
===================================================================
--- clang/include/clang/Basic/CodeGenOptions.def
+++ clang/include/clang/Basic/CodeGenOptions.def
@@ -139,6 +139,9 @@
VALUE_CODEGENOPT(PatchableFunctionEntryCount , 32, 0) ///< Number of NOPs at function entry
VALUE_CODEGENOPT(PatchableFunctionEntryOffset , 32, 0)
+CODEGENOPT(HotPatch, 1, 0) ///< Supports the Microsoft /HOTPATCH flag and
+ ///< generates a 'patchable-function' attribute.
+
CODEGENOPT(InstrumentForProfiling , 1, 0) ///< Set when -pg is enabled.
CODEGENOPT(CallFEntry , 1, 0) ///< Set when -mfentry is enabled.
CODEGENOPT(MNopMCount , 1, 0) ///< Set when -mnop-mcount is enabled.
Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -136,6 +136,16 @@
or pass ``/permissive`` to disable C++ operator names altogether. See
`PR42427 <https://llvm.org/pr42427>` for more info.
+- Add support for MSVC-compatible ``/hotpatch`` flag in clang-cl, and equivalent
+ -cc1 flag ``-fms-hotpatch``. Along with the linker flag ``/functionpadmin``
+ this creates executable images suitable for runtime code patching. This flag
+ is only required for x86/x64 targets; ARM/ARM64 simply needs the linker
+ ``/functionpadmin``.
+
+ With this addition, clang-cl can be used in live code patching scenarios,
+ along with tools such as Live++ or Recode. Microsoft Edit and Continue isn't
+ currently supported.
+
C Language Changes in Clang
---------------------------
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