[PATCH] D124762: [WinEHPrepare] Avoid truncation of EH funclets with GNUstep ObjC runtime

[Stefan Gränitz via Phabricator via cfe-commits]

sgraenitz abandoned this revision.
sgraenitz added a comment.

Close in favor of the D128190 , which covers 
both cases at once: emit (was D124762 ) and 
inline (was D127962 )


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[PATCH] D124762: [WinEHPrepare] Avoid truncation of EH funclets with GNUstep ObjC runtime

[Stefan Gränitz via Phabricator via cfe-commits]

sgraenitz updated this revision to Diff 437180.
sgraenitz added a comment.

Drop GNUstep assertion from getBundlesForFunclet(). Indeed a similar issue was 
observed before. See: D44640 


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Files:
  clang/lib/CodeGen/CGCall.cpp
  clang/test/CodeGenObjCXX/arc-exceptions-seh.mm
  llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
  llvm/lib/CodeGen/WinEHPrepare.cpp
  llvm/test/CodeGen/X86/win64-funclet-preisel-intrinsics.ll

Index: llvm/test/CodeGen/X86/win64-funclet-preisel-intrinsics.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/win64-funclet-preisel-intrinsics.ll
@@ -0,0 +1,68 @@
+; RUN: llc -mtriple=x86_64-windows-msvc < %s | FileCheck %s
+
+; Reduced IR generated from ObjC++ source:
+;
+; @class Ety;
+; void opaque(void);
+; void test_catch(void) {
+;   @try {
+; opaque();
+;   } @catch (Ety *ex) {
+; // Destroy ex when leaving catchpad. This emits calls to two intrinsic
+; // functions, llvm.objc.retain and llvm.objc.storeStrong, but only one
+; // is required to trigger the funclet truncation.
+;   }
+; }
+
+define void @test_catch() personality ptr @__CxxFrameHandler3 {
+entry:
+  %exn.slot = alloca ptr, align 8
+  %ex2 = alloca ptr, align 8
+  invoke void @opaque() to label %invoke.cont unwind label %catch.dispatch
+
+catch.dispatch:
+  %0 = catchswitch within none [label %catch] unwind to caller
+
+invoke.cont:
+  unreachable
+
+catch:
+  %1 = catchpad within %0 [ptr null, i32 64, ptr %exn.slot]
+  call void @llvm.objc.storeStrong(ptr %ex2, ptr null) [ "funclet"(token %1) ]
+  catchret from %1 to label %catchret.dest
+
+catchret.dest:
+  ret void
+}
+
+declare void @opaque()
+declare void @llvm.objc.storeStrong(ptr, ptr) #0
+declare i32 @__CxxFrameHandler3(...)
+
+attributes #0 = { nounwind }
+
+; llvm.objc.storeStrong is a Pre-ISel intrinsic, which used to cause truncations
+; when it occurred in SEH funclets like catchpads:
+; CHECK: # %catch
+; CHECK: pushq   %rbp
+; CHECK: .seh_pushreg %rbp
+;...
+; CHECK: .seh_endprologue
+;
+; At this point the code used to be truncated (and sometimes terminated with an
+; int3 opcode):
+; CHECK-NOT: int3
+;
+; Instead, the call to objc_storeStrong should be emitted:
+; CHECK: leaq	-24(%rbp), %rcx
+; CHECK: xorl	%edx, %edx
+; CHECK: callq	objc_storeStrong
+;...
+; 
+; This is the end of the funclet:
+; CHECK: popq	%rbp
+; CHECK: retq# CATCHRET
+;...
+; CHECK: .seh_handlerdata
+;...
+; CHECK: .seh_endproc
Index: llvm/lib/CodeGen/WinEHPrepare.cpp
===
--- llvm/lib/CodeGen/WinEHPrepare.cpp
+++ llvm/lib/CodeGen/WinEHPrepare.cpp
@@ -963,7 +963,7 @@
 if (auto BU = CB->getOperandBundle(LLVMContext::OB_funclet))
   FuncletBundleOperand = BU->Inputs.front();
 
-if (FuncletBundleOperand == FuncletPad)
+if (!FuncletPad || FuncletBundleOperand == FuncletPad)
   continue;
 
 // Skip call sites which are nounwind intrinsics or inline asm.
Index: llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
===
--- llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
+++ llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
@@ -107,7 +107,9 @@
 
 IRBuilder<> Builder(CI->getParent(), CI->getIterator());
 SmallVector Args(CI->args());
-CallInst *NewCI = Builder.CreateCall(FCache, Args);
+SmallVector BundleList;
+CI->getOperandBundlesAsDefs(BundleList);
+CallInst *NewCI = Builder.CreateCall(FCache, Args, BundleList);
 NewCI->setName(CI->getName());
 
 // Try to set the most appropriate TailCallKind based on both the current
Index: clang/test/CodeGenObjCXX/arc-exceptions-seh.mm
===
--- /dev/null
+++ clang/test/CodeGenObjCXX/arc-exceptions-seh.mm
@@ -0,0 +1,23 @@
+// RUN: %clang_cc1 -triple x86_64-pc-windows-msvc -emit-llvm -fobjc-arc -fexceptions -fobjc-exceptions -fobjc-runtime=gnustep-2.0 -o - %s | FileCheck %s
+
+@class Ety;
+void opaque(void);
+void test_catch_preisel_intrinsic(void) {
+  @try {
+opaque();
+  } @catch (Ety *ex) {
+// Destroy ex when leaving catchpad. Emits calls to two intrinsic functions,
+// that should both have a "funclet" bundle operand that refers to the
+// catchpad's SSA value.
+  }
+}
+
+// CHECK-LABEL: define{{.*}} void {{.*}}test_catch_preisel_intrinsic
+//...
+// CHECK:   catch.dispatch:
+// CHECK-NEXT:[[CATCHSWITCH:%[0-9]+]] = catchswitch within none
+//...
+// CHECK:   catch:
+// CHECK-NEXT:[[CATCHPAD:%[0-9]+]] = catchpad within 

[PATCH] D124762: [WinEHPrepare] Avoid truncation of EH funclets with GNUstep ObjC runtime

[Stefan Gränitz via Phabricator via cfe-commits]

sgraenitz updated this revision to Diff 437179.
sgraenitz added a comment.

Fix accidental functional change that failed Clang test 
CodeGenCXX/microsoft-abi-eh-inlineasm.cpp


Repository:
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Files:
  clang/lib/CodeGen/CGCall.cpp
  clang/test/CodeGenObjCXX/arc-exceptions-seh.mm
  llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
  llvm/lib/CodeGen/WinEHPrepare.cpp
  llvm/test/CodeGen/X86/win64-funclet-preisel-intrinsics.ll

Index: llvm/test/CodeGen/X86/win64-funclet-preisel-intrinsics.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/win64-funclet-preisel-intrinsics.ll
@@ -0,0 +1,68 @@
+; RUN: llc -mtriple=x86_64-windows-msvc < %s | FileCheck %s
+
+; Reduced IR generated from ObjC++ source:
+;
+; @class Ety;
+; void opaque(void);
+; void test_catch(void) {
+;   @try {
+; opaque();
+;   } @catch (Ety *ex) {
+; // Destroy ex when leaving catchpad. This emits calls to two intrinsic
+; // functions, llvm.objc.retain and llvm.objc.storeStrong, but only one
+; // is required to trigger the funclet truncation.
+;   }
+; }
+
+define void @test_catch() personality ptr @__CxxFrameHandler3 {
+entry:
+  %exn.slot = alloca ptr, align 8
+  %ex2 = alloca ptr, align 8
+  invoke void @opaque() to label %invoke.cont unwind label %catch.dispatch
+
+catch.dispatch:
+  %0 = catchswitch within none [label %catch] unwind to caller
+
+invoke.cont:
+  unreachable
+
+catch:
+  %1 = catchpad within %0 [ptr null, i32 64, ptr %exn.slot]
+  call void @llvm.objc.storeStrong(ptr %ex2, ptr null) [ "funclet"(token %1) ]
+  catchret from %1 to label %catchret.dest
+
+catchret.dest:
+  ret void
+}
+
+declare void @opaque()
+declare void @llvm.objc.storeStrong(ptr, ptr) #0
+declare i32 @__CxxFrameHandler3(...)
+
+attributes #0 = { nounwind }
+
+; llvm.objc.storeStrong is a Pre-ISel intrinsic, which used to cause truncations
+; when it occurred in SEH funclets like catchpads:
+; CHECK: # %catch
+; CHECK: pushq   %rbp
+; CHECK: .seh_pushreg %rbp
+;...
+; CHECK: .seh_endprologue
+;
+; At this point the code used to be truncated (and sometimes terminated with an
+; int3 opcode):
+; CHECK-NOT: int3
+;
+; Instead, the call to objc_storeStrong should be emitted:
+; CHECK: leaq	-24(%rbp), %rcx
+; CHECK: xorl	%edx, %edx
+; CHECK: callq	objc_storeStrong
+;...
+; 
+; This is the end of the funclet:
+; CHECK: popq	%rbp
+; CHECK: retq# CATCHRET
+;...
+; CHECK: .seh_handlerdata
+;...
+; CHECK: .seh_endproc
Index: llvm/lib/CodeGen/WinEHPrepare.cpp
===
--- llvm/lib/CodeGen/WinEHPrepare.cpp
+++ llvm/lib/CodeGen/WinEHPrepare.cpp
@@ -963,7 +963,7 @@
 if (auto BU = CB->getOperandBundle(LLVMContext::OB_funclet))
   FuncletBundleOperand = BU->Inputs.front();
 
-if (FuncletBundleOperand == FuncletPad)
+if (!FuncletPad || FuncletBundleOperand == FuncletPad)
   continue;
 
 // Skip call sites which are nounwind intrinsics or inline asm.
Index: llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
===
--- llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
+++ llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
@@ -107,7 +107,9 @@
 
 IRBuilder<> Builder(CI->getParent(), CI->getIterator());
 SmallVector Args(CI->args());
-CallInst *NewCI = Builder.CreateCall(FCache, Args);
+SmallVector BundleList;
+CI->getOperandBundlesAsDefs(BundleList);
+CallInst *NewCI = Builder.CreateCall(FCache, Args, BundleList);
 NewCI->setName(CI->getName());
 
 // Try to set the most appropriate TailCallKind based on both the current
Index: clang/test/CodeGenObjCXX/arc-exceptions-seh.mm
===
--- /dev/null
+++ clang/test/CodeGenObjCXX/arc-exceptions-seh.mm
@@ -0,0 +1,23 @@
+// RUN: %clang_cc1 -triple x86_64-pc-windows-msvc -emit-llvm -fobjc-arc -fexceptions -fobjc-exceptions -fobjc-runtime=gnustep-2.0 -o - %s | FileCheck %s
+
+@class Ety;
+void opaque(void);
+void test_catch_preisel_intrinsic(void) {
+  @try {
+opaque();
+  } @catch (Ety *ex) {
+// Destroy ex when leaving catchpad. Emits calls to two intrinsic functions,
+// that should both have a "funclet" bundle operand that refers to the
+// catchpad's SSA value.
+  }
+}
+
+// CHECK-LABEL: define{{.*}} void {{.*}}test_catch_preisel_intrinsic
+//...
+// CHECK:   catch.dispatch:
+// CHECK-NEXT:[[CATCHSWITCH:%[0-9]+]] = catchswitch within none
+//...
+// CHECK:   catch:
+// CHECK-NEXT:[[CATCHPAD:%[0-9]+]] = catchpad within [[CATCHSWITCH]]
+// CHECK: {{%[0-9]+}} = 

[PATCH] D124762: [WinEHPrepare] Avoid truncation of EH funclets with GNUstep ObjC runtime

[Stefan Gränitz via Phabricator via cfe-commits]

sgraenitz updated this revision to Diff 436730.
sgraenitz added a comment.

Update LLVM CodeGen test for mainline opaque pointers


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Files:
  clang/lib/CodeGen/CGCall.cpp
  clang/test/CodeGenObjCXX/arc-exceptions-seh.mm
  llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
  llvm/lib/CodeGen/WinEHPrepare.cpp
  llvm/test/CodeGen/X86/win64-funclet-preisel-intrinsics.ll

Index: llvm/test/CodeGen/X86/win64-funclet-preisel-intrinsics.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/win64-funclet-preisel-intrinsics.ll
@@ -0,0 +1,68 @@
+; RUN: llc -mtriple=x86_64-windows-msvc < %s | FileCheck %s
+
+; Reduced IR generated from ObjC++ source:
+;
+; @class Ety;
+; void opaque(void);
+; void test_catch(void) {
+;   @try {
+; opaque();
+;   } @catch (Ety *ex) {
+; // Destroy ex when leaving catchpad. This emits calls to two intrinsic
+; // functions, llvm.objc.retain and llvm.objc.storeStrong, but only one
+; // is required to trigger the funclet truncation.
+;   }
+; }
+
+define void @test_catch() personality ptr @__CxxFrameHandler3 {
+entry:
+  %exn.slot = alloca ptr, align 8
+  %ex2 = alloca ptr, align 8
+  invoke void @opaque() to label %invoke.cont unwind label %catch.dispatch
+
+catch.dispatch:
+  %0 = catchswitch within none [label %catch] unwind to caller
+
+invoke.cont:
+  unreachable
+
+catch:
+  %1 = catchpad within %0 [ptr null, i32 64, ptr %exn.slot]
+  call void @llvm.objc.storeStrong(ptr %ex2, ptr null) [ "funclet"(token %1) ]
+  catchret from %1 to label %catchret.dest
+
+catchret.dest:
+  ret void
+}
+
+declare void @opaque()
+declare void @llvm.objc.storeStrong(ptr, ptr) #0
+declare i32 @__CxxFrameHandler3(...)
+
+attributes #0 = { nounwind }
+
+; llvm.objc.storeStrong is a Pre-ISel intrinsic, which used to cause truncations
+; when it occurred in SEH funclets like catchpads:
+; CHECK: # %catch
+; CHECK: pushq   %rbp
+; CHECK: .seh_pushreg %rbp
+;...
+; CHECK: .seh_endprologue
+;
+; At this point the code used to be truncated (and sometimes terminated with an
+; int3 opcode):
+; CHECK-NOT: int3
+;
+; Instead, the call to objc_storeStrong should be emitted:
+; CHECK: leaq	-24(%rbp), %rcx
+; CHECK: xorl	%edx, %edx
+; CHECK: callq	objc_storeStrong
+;...
+; 
+; This is the end of the funclet:
+; CHECK: popq	%rbp
+; CHECK: retq# CATCHRET
+;...
+; CHECK: .seh_handlerdata
+;...
+; CHECK: .seh_endproc
Index: llvm/lib/CodeGen/WinEHPrepare.cpp
===
--- llvm/lib/CodeGen/WinEHPrepare.cpp
+++ llvm/lib/CodeGen/WinEHPrepare.cpp
@@ -963,7 +963,7 @@
 if (auto BU = CB->getOperandBundle(LLVMContext::OB_funclet))
   FuncletBundleOperand = BU->Inputs.front();
 
-if (FuncletBundleOperand == FuncletPad)
+if (!FuncletPad || FuncletBundleOperand == FuncletPad)
   continue;
 
 // Skip call sites which are nounwind intrinsics or inline asm.
Index: llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
===
--- llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
+++ llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
@@ -107,7 +107,9 @@
 
 IRBuilder<> Builder(CI->getParent(), CI->getIterator());
 SmallVector Args(CI->args());
-CallInst *NewCI = Builder.CreateCall(FCache, Args);
+SmallVector BundleList;
+CI->getOperandBundlesAsDefs(BundleList);
+CallInst *NewCI = Builder.CreateCall(FCache, Args, BundleList);
 NewCI->setName(CI->getName());
 
 // Try to set the most appropriate TailCallKind based on both the current
Index: clang/test/CodeGenObjCXX/arc-exceptions-seh.mm
===
--- /dev/null
+++ clang/test/CodeGenObjCXX/arc-exceptions-seh.mm
@@ -0,0 +1,23 @@
+// RUN: %clang_cc1 -triple x86_64-pc-windows-msvc -emit-llvm -fobjc-arc -fexceptions -fobjc-exceptions -fobjc-runtime=gnustep-2.0 -o - %s | FileCheck %s
+
+@class Ety;
+void opaque(void);
+void test_catch_preisel_intrinsic(void) {
+  @try {
+opaque();
+  } @catch (Ety *ex) {
+// Destroy ex when leaving catchpad. Emits calls to two intrinsic functions,
+// that should both have a "funclet" bundle operand that refers to the
+// catchpad's SSA value.
+  }
+}
+
+// CHECK-LABEL: define{{.*}} void {{.*}}test_catch_preisel_intrinsic
+//...
+// CHECK:   catch.dispatch:
+// CHECK-NEXT:[[CATCHSWITCH:%[0-9]+]] = catchswitch within none
+//...
+// CHECK:   catch:
+// CHECK-NEXT:[[CATCHPAD:%[0-9]+]] = catchpad within [[CATCHSWITCH]]
+// CHECK: {{%[0-9]+}} = call {{.*}} @llvm.objc.retain{{.*}} [ 

[PATCH] D124762: [WinEHPrepare] Avoid truncation of EH funclets with GNUstep ObjC runtime

[Stefan Gränitz via Phabricator via cfe-commits]

sgraenitz added a comment.

For illustration, truncations look like this:

F23303573: Screenshot 2022-06-02 at 15.35.19.png 


F23303572: Screenshot 2022-06-02 at 19.06.41.png 



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[PATCH] D124762: [WinEHPrepare] Avoid truncation of EH funclets with GNUstep ObjC runtime

[Stefan Gränitz via Phabricator via cfe-commits]

sgraenitz marked an inline comment as done.
sgraenitz added a comment.

My follow-up got delayed, because I hit another bug, which appears to be a 
regression in release 14. This is why I wrote the tests for release/13.x and I 
still have to port them back to mainline, so this is *not yet ready to land*. 
As I don't expect it to cause big changes, however, I though it might be good 
to update the review anyway.

Rebased on release/13.x I am running the tests like this and both are passing:

  > ninja llvm-config llvm-readobj llc FileCheck count not
  > bin\llvm-lit.py --filter=win64-funclet-preisel-intrinsics test\CodeGen\X86
  > ninja clang
  > bin\llvm-lit.py --filter=arc-exceptions-seh tools\clang\test

@rnk What do you think about implementation, naming, etc. Is that ok?

In D124762#3486288 , @rnk wrote:

> Lastly, I think the inliner needs to be taught that these intrinsics need to 
> carry operand bundles, otherwise this problem will arise after optimization. 
> The inliner has the same logic here:
> https://github.com/llvm/llvm-project/blob/main/llvm/lib/Transforms/Utils/InlineFunction.cpp#L2311

Thanks for the note. Yes, I can reproduce that. I am not yet sure what's the 
best way to fix it though. Actually, I'd prefer to split it out into a separate 
review, so the two discussions can remain their individual focus. What do you 
think?




Comment at: clang/test/CodeGenObjCXX/arc-exceptions-seh.mm:1
+// RUN: %clang_cc1 -triple x86_64-pc-windows-msvc -emit-llvm -fobjc-arc 
-fexceptions -fobjc-exceptions -fobjc-runtime=gnustep-2.0 -o - %s | FileCheck %s
+

Note: There is another test without the `-seh` postfix that checks very similar 
situations for CodeGen with the macOS runtime.



Comment at: llvm/lib/CodeGen/WinEHPrepare.cpp:966
 
-if (FuncletBundleOperand == FuncletPad)
+if (!FuncletPad || FuncletBundleOperand == FuncletPad)
   continue;

sgraenitz wrote:
> rnk wrote:
> > Is this change necessary? It seems like it shouldn't be after the clang and 
> > preisel pass changes.
> Yes, apparently it is necessary. There are cases, where 
> `CodeGenFunction::getBundlesForFunclet()` registers a "funclet" bundle 
> operand, but the `FuncletPad` here is null. My guess was it might be due to 
> optimizations?
Might that be due to the inliner issue then? I'd address it in the follow-up 
review if it's ok?



Comment at: llvm/test/CodeGen/X86/win64-funclet-preisel-intrinsics.ll:53
+; At this point the code used to be truncated:
+; CHECK-NOT: int3
+;

Another side-note: Often times Clang just didn't emit anything here, so 
execution would run into whatever code comes next. The `int3` I sometimes got 
might as well have been "accidental" padding.


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[PATCH] D124762: [WinEHPrepare] Avoid truncation of EH funclets with GNUstep ObjC runtime

[Stefan Gränitz via Phabricator via cfe-commits]

sgraenitz updated this revision to Diff 434024.
sgraenitz added a comment.

Clang frontend: check that 'funclet' bundle operands are emitted for Pre-ISel 
intrinsics


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Files:
  clang/lib/CodeGen/CGCall.cpp
  clang/test/CodeGenObjCXX/arc-exceptions-seh.mm
  llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
  llvm/lib/CodeGen/WinEHPrepare.cpp
  llvm/test/CodeGen/X86/win64-funclet-preisel-intrinsics.ll

Index: llvm/test/CodeGen/X86/win64-funclet-preisel-intrinsics.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/win64-funclet-preisel-intrinsics.ll
@@ -0,0 +1,67 @@
+; RUN: llc -mtriple=x86_64-windows-msvc < %s | FileCheck %s
+
+; Reduced IR generated from ObjC++ source:
+;
+; @class Ety;
+; void opaque(void);
+; void test_catch(void) {
+;   @try {
+; opaque();
+;   } @catch (Ety *ex) {
+; // Destroy ex when leaving catchpad. This emits calls to two intrinsic
+; // functions, llvm.objc.retain and llvm.objc.storeStrong, but only one
+; // is required to trigger the funclet truncation.
+;   }
+; }
+
+define void @test_catch() personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*) {
+entry:
+  %exn.slot = alloca i8*, align 8
+  %ex2 = alloca i8*, align 8
+  invoke void @opaque() to label %invoke.cont unwind label %catch.dispatch
+
+catch.dispatch:
+  %0 = catchswitch within none [label %catch] unwind to caller
+
+invoke.cont:
+  unreachable
+
+catch:
+  %1 = catchpad within %0 [i8* null, i32 64, i8** %exn.slot]
+  call void @llvm.objc.storeStrong(i8** %ex2, i8* null) [ "funclet"(token %1) ]
+  catchret from %1 to label %catchret.dest
+
+catchret.dest:
+  ret void
+}
+
+declare void @opaque()
+declare void @llvm.objc.storeStrong(i8**, i8*) #0
+declare i32 @__CxxFrameHandler3(...)
+
+attributes #0 = { nounwind }
+
+; llvm.objc.storeStrong is a Pre-ISel intrinsic, which used to cause truncations
+; when it occurred in SEH funclets like catchpads:
+; CHECK: # %catch
+; CHECK: pushq   %rbp
+; CHECK: .seh_pushreg %rbp
+;...
+; CHECK: .seh_endprologue
+;
+; At this point the code used to be truncated:
+; CHECK-NOT: int3
+;
+; Instead, the call to objc_storeStrong should be emitted:
+; CHECK: leaq	-24(%rbp), %rcx
+; CHECK: xorl	%edx, %edx
+; CHECK: callq	objc_storeStrong
+;...
+; 
+; This is the end of the funclet:
+; CHECK: popq	%rbp
+; CHECK: retq# CATCHRET
+;...
+; CHECK: .seh_handlerdata
+;...
+; CHECK: .seh_endproc
Index: llvm/lib/CodeGen/WinEHPrepare.cpp
===
--- llvm/lib/CodeGen/WinEHPrepare.cpp
+++ llvm/lib/CodeGen/WinEHPrepare.cpp
@@ -963,7 +963,7 @@
 if (auto BU = CB->getOperandBundle(LLVMContext::OB_funclet))
   FuncletBundleOperand = BU->Inputs.front();
 
-if (FuncletBundleOperand == FuncletPad)
+if (!FuncletPad || FuncletBundleOperand == FuncletPad)
   continue;
 
 // Skip call sites which are nounwind intrinsics or inline asm.
Index: llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
===
--- llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
+++ llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
@@ -107,7 +107,9 @@
 
 IRBuilder<> Builder(CI->getParent(), CI->getIterator());
 SmallVector Args(CI->args());
-CallInst *NewCI = Builder.CreateCall(FCache, Args);
+SmallVector BundleList;
+CI->getOperandBundlesAsDefs(BundleList);
+CallInst *NewCI = Builder.CreateCall(FCache, Args, BundleList);
 NewCI->setName(CI->getName());
 
 // Try to set the most appropriate TailCallKind based on both the current
Index: clang/test/CodeGenObjCXX/arc-exceptions-seh.mm
===
--- /dev/null
+++ clang/test/CodeGenObjCXX/arc-exceptions-seh.mm
@@ -0,0 +1,23 @@
+// RUN: %clang_cc1 -triple x86_64-pc-windows-msvc -emit-llvm -fobjc-arc -fexceptions -fobjc-exceptions -fobjc-runtime=gnustep-2.0 -o - %s | FileCheck %s
+
+@class Ety;
+void opaque(void);
+void test_catch_preisel_intrinsic(void) {
+  @try {
+opaque();
+  } @catch (Ety *ex) {
+// Destroy ex when leaving catchpad. Emits calls to two intrinsic functions,
+// that should both have a "funclet" bundle operand that refers to the
+// catchpad's SSA value.
+  }
+}
+
+// CHECK-LABEL: define{{.*}} void {{.*}}test_catch_preisel_intrinsic
+//...
+// CHECK:   catch.dispatch:
+// CHECK-NEXT:[[CATCHSWITCH:%[0-9]+]] = catchswitch within none
+//...
+// CHECK:   catch:
+// CHECK-NEXT:[[CATCHPAD:%[0-9]+]] = catchpad within [[CATCHSWITCH]]
+// CHECK: {{%[0-9]+}} = call {{.*}} 

[PATCH] D124762: [WinEHPrepare] Avoid truncation of EH funclets with GNUstep ObjC runtime

[Stefan Gränitz via Phabricator via cfe-commits]

sgraenitz updated this revision to Diff 434023.
sgraenitz added a comment.
Herald added subscribers: jsji, pengfei.

LLVM CodeGen: check that presence of bundle operands avoids truncation


Repository:
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CHANGES SINCE LAST ACTION
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Files:
  clang/lib/CodeGen/CGCall.cpp
  llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
  llvm/lib/CodeGen/WinEHPrepare.cpp
  llvm/test/CodeGen/X86/win64-funclet-preisel-intrinsics.ll

Index: llvm/test/CodeGen/X86/win64-funclet-preisel-intrinsics.ll
===
--- /dev/null
+++ llvm/test/CodeGen/X86/win64-funclet-preisel-intrinsics.ll
@@ -0,0 +1,67 @@
+; RUN: llc -mtriple=x86_64-windows-msvc < %s | FileCheck %s
+
+; Reduced IR generated from ObjC++ source:
+;
+; @class Ety;
+; void opaque(void);
+; void test_catch(void) {
+;   @try {
+; opaque();
+;   } @catch (Ety *ex) {
+; // Destroy ex when leaving catchpad. This emits calls to two intrinsic
+; // functions, llvm.objc.retain and llvm.objc.storeStrong, but only one
+; // is required to trigger the funclet truncation.
+;   }
+; }
+
+define void @test_catch() personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*) {
+entry:
+  %exn.slot = alloca i8*, align 8
+  %ex2 = alloca i8*, align 8
+  invoke void @opaque() to label %invoke.cont unwind label %catch.dispatch
+
+catch.dispatch:
+  %0 = catchswitch within none [label %catch] unwind to caller
+
+invoke.cont:
+  unreachable
+
+catch:
+  %1 = catchpad within %0 [i8* null, i32 64, i8** %exn.slot]
+  call void @llvm.objc.storeStrong(i8** %ex2, i8* null) [ "funclet"(token %1) ]
+  catchret from %1 to label %catchret.dest
+
+catchret.dest:
+  ret void
+}
+
+declare void @opaque()
+declare void @llvm.objc.storeStrong(i8**, i8*) #0
+declare i32 @__CxxFrameHandler3(...)
+
+attributes #0 = { nounwind }
+
+; llvm.objc.storeStrong is a Pre-ISel intrinsic, which used to cause truncations
+; when it occurred in SEH funclets like catchpads:
+; CHECK: # %catch
+; CHECK: pushq   %rbp
+; CHECK: .seh_pushreg %rbp
+;...
+; CHECK: .seh_endprologue
+;
+; At this point the code used to be truncated:
+; CHECK-NOT: int3
+;
+; Instead, the call to objc_storeStrong should be emitted:
+; CHECK: leaq	-24(%rbp), %rcx
+; CHECK: xorl	%edx, %edx
+; CHECK: callq	objc_storeStrong
+;...
+; 
+; This is the end of the funclet:
+; CHECK: popq	%rbp
+; CHECK: retq# CATCHRET
+;...
+; CHECK: .seh_handlerdata
+;...
+; CHECK: .seh_endproc
Index: llvm/lib/CodeGen/WinEHPrepare.cpp
===
--- llvm/lib/CodeGen/WinEHPrepare.cpp
+++ llvm/lib/CodeGen/WinEHPrepare.cpp
@@ -963,7 +963,7 @@
 if (auto BU = CB->getOperandBundle(LLVMContext::OB_funclet))
   FuncletBundleOperand = BU->Inputs.front();
 
-if (FuncletBundleOperand == FuncletPad)
+if (!FuncletPad || FuncletBundleOperand == FuncletPad)
   continue;
 
 // Skip call sites which are nounwind intrinsics or inline asm.
Index: llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
===
--- llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
+++ llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
@@ -107,7 +107,9 @@
 
 IRBuilder<> Builder(CI->getParent(), CI->getIterator());
 SmallVector Args(CI->args());
-CallInst *NewCI = Builder.CreateCall(FCache, Args);
+SmallVector BundleList;
+CI->getOperandBundlesAsDefs(BundleList);
+CallInst *NewCI = Builder.CreateCall(FCache, Args, BundleList);
 NewCI->setName(CI->getName());
 
 // Try to set the most appropriate TailCallKind based on both the current
Index: clang/lib/CodeGen/CGCall.cpp
===
--- clang/lib/CodeGen/CGCall.cpp
+++ clang/lib/CodeGen/CGCall.cpp
@@ -25,11 +25,13 @@
 #include "clang/AST/DeclCXX.h"
 #include "clang/AST/DeclObjC.h"
 #include "clang/Basic/CodeGenOptions.h"
+#include "clang/Basic/ObjCRuntime.h"
 #include "clang/Basic/TargetBuiltins.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/CodeGen/CGFunctionInfo.h"
 #include "clang/CodeGen/SwiftCallingConv.h"
 #include "llvm/ADT/StringExtras.h"
+#include "llvm/Analysis/ObjCARCInstKind.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/IR/Assumptions.h"
 #include "llvm/IR/Attributes.h"
@@ -4465,16 +4467,37 @@
 CodeGenFunction::getBundlesForFunclet(llvm::Value *Callee) {
   SmallVector BundleList;
   // There is no need for a funclet operand bundle if we aren't inside a
-  // funclet.
+  // funclet or the callee is not a function.
   if (!CurrentFuncletPad)
 return BundleList;
-
-  // Skip intrinsics which cannot throw.
   auto *CalleeFn = 

[PATCH] D124762: [WinEHPrepare] Avoid truncation of EH funclets with GNUstep ObjC runtime

[Stefan Gränitz via Phabricator via cfe-commits]

sgraenitz updated this revision to Diff 434020.
sgraenitz added a comment.

Fix unchecked nullptr compiler crash and assertion


Repository:
  rG LLVM Github Monorepo

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Files:
  clang/lib/CodeGen/CGCall.cpp
  llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
  llvm/lib/CodeGen/WinEHPrepare.cpp


Index: llvm/lib/CodeGen/WinEHPrepare.cpp
===
--- llvm/lib/CodeGen/WinEHPrepare.cpp
+++ llvm/lib/CodeGen/WinEHPrepare.cpp
@@ -963,7 +963,7 @@
 if (auto BU = CB->getOperandBundle(LLVMContext::OB_funclet))
   FuncletBundleOperand = BU->Inputs.front();
 
-if (FuncletBundleOperand == FuncletPad)
+if (!FuncletPad || FuncletBundleOperand == FuncletPad)
   continue;
 
 // Skip call sites which are nounwind intrinsics or inline asm.
Index: llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
===
--- llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
+++ llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
@@ -107,7 +107,9 @@
 
 IRBuilder<> Builder(CI->getParent(), CI->getIterator());
 SmallVector Args(CI->args());
-CallInst *NewCI = Builder.CreateCall(FCache, Args);
+SmallVector BundleList;
+CI->getOperandBundlesAsDefs(BundleList);
+CallInst *NewCI = Builder.CreateCall(FCache, Args, BundleList);
 NewCI->setName(CI->getName());
 
 // Try to set the most appropriate TailCallKind based on both the current
Index: clang/lib/CodeGen/CGCall.cpp
===
--- clang/lib/CodeGen/CGCall.cpp
+++ clang/lib/CodeGen/CGCall.cpp
@@ -25,11 +25,13 @@
 #include "clang/AST/DeclCXX.h"
 #include "clang/AST/DeclObjC.h"
 #include "clang/Basic/CodeGenOptions.h"
+#include "clang/Basic/ObjCRuntime.h"
 #include "clang/Basic/TargetBuiltins.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/CodeGen/CGFunctionInfo.h"
 #include "clang/CodeGen/SwiftCallingConv.h"
 #include "llvm/ADT/StringExtras.h"
+#include "llvm/Analysis/ObjCARCInstKind.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/IR/Assumptions.h"
 #include "llvm/IR/Attributes.h"
@@ -4465,16 +4467,37 @@
 CodeGenFunction::getBundlesForFunclet(llvm::Value *Callee) {
   SmallVector BundleList;
   // There is no need for a funclet operand bundle if we aren't inside a
-  // funclet.
+  // funclet or the callee is not a function.
   if (!CurrentFuncletPad)
 return BundleList;
-
-  // Skip intrinsics which cannot throw.
   auto *CalleeFn = dyn_cast(Callee->stripPointerCasts());
-  if (CalleeFn && CalleeFn->isIntrinsic() && CalleeFn->doesNotThrow())
+  if (!CalleeFn)
 return BundleList;
 
-  BundleList.emplace_back("funclet", CurrentFuncletPad);
+  // Skip intrinsics which cannot throw.
+  bool InsertFuncletOp = true;
+  if (CalleeFn->isIntrinsic() && CalleeFn->doesNotThrow())
+InsertFuncletOp = false;
+
+  // Most ObjC ARC intrinics are lowered in PreISelIntrinsicLowering. Thus,
+  // WinEHPrepare will see them as regular calls. We need to set the funclet
+  // operand explicitly in this case to avoid accidental truncation of EH
+  // funclets on Windows.
+  if (CalleeFn->isIntrinsic() && CalleeFn->doesNotThrow()) {
+if (CGM.getTarget().getTriple().isOSWindows()) {
+  assert(CGM.getLangOpts().ObjCRuntime.getKind() == ObjCRuntime::GNUstep &&
+ "Only reproduced with GNUstep so far, but likely applies to other 
"
+ "ObjC runtimes on Windows");
+  using namespace llvm::objcarc;
+  ARCInstKind CalleeKind = GetFunctionClass(CalleeFn);
+  if (!IsUser(CalleeKind) && CalleeKind != ARCInstKind::None)
+InsertFuncletOp = true;
+}
+  }
+
+  if (InsertFuncletOp)
+BundleList.emplace_back("funclet", CurrentFuncletPad);
+
   return BundleList;
 }
 


Index: llvm/lib/CodeGen/WinEHPrepare.cpp
===
--- llvm/lib/CodeGen/WinEHPrepare.cpp
+++ llvm/lib/CodeGen/WinEHPrepare.cpp
@@ -963,7 +963,7 @@
 if (auto BU = CB->getOperandBundle(LLVMContext::OB_funclet))
   FuncletBundleOperand = BU->Inputs.front();
 
-if (FuncletBundleOperand == FuncletPad)
+if (!FuncletPad || FuncletBundleOperand == FuncletPad)
   continue;
 
 // Skip call sites which are nounwind intrinsics or inline asm.
Index: llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
===
--- llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
+++ llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
@@ -107,7 +107,9 @@
 
 IRBuilder<> Builder(CI->getParent(), CI->getIterator());
 SmallVector Args(CI->args());
-CallInst *NewCI = Builder.CreateCall(FCache, Args);
+SmallVector BundleList;
+CI->getOperandBundlesAsDefs(BundleList);
+CallInst *NewCI = Builder.CreateCall(FCache, Args, 

[PATCH] D124762: [WinEHPrepare] Avoid truncation of EH funclets with GNUstep ObjC runtime

[Stefan Gränitz via Phabricator via cfe-commits]

sgraenitz added a comment.

Thanks for your help! I will work on testing in calendar week 21.




Comment at: llvm/lib/CodeGen/WinEHPrepare.cpp:966
 
-if (FuncletBundleOperand == FuncletPad)
+if (!FuncletPad || FuncletBundleOperand == FuncletPad)
   continue;

rnk wrote:
> Is this change necessary? It seems like it shouldn't be after the clang and 
> preisel pass changes.
Yes, apparently it is necessary. There are cases, where 
`CodeGenFunction::getBundlesForFunclet()` registers a "funclet" bundle operand, 
but the `FuncletPad` here is null. My guess was it might be due to 
optimizations?


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[PATCH] D124762: [WinEHPrepare] Avoid truncation of EH funclets with GNUstep ObjC runtime

[Reid Kleckner via Phabricator via cfe-commits]

rnk added a comment.

Thanks!

In D124762#3485478 , @sgraenitz wrote:

> I guess testing must be split in two:
>
> - Clang wants to make sure the "funclet" bundle operand gets emitted for ObjC 
> ARC runtime calls on Windows. Maybe that fits into 
> clang/test/CodeGenObjC/gnu-exceptions.m 
> ?

That seems like a good template for a new test. I think it probably deserves 
its own file. I imagine it will grow to be a more extensive test suite covering 
the interaction between GNUstep Objective C exceptions and WinEH.

> - LLVM wants to check that WinEHPrepare handles these runtime calls 
> correctly. For that maybe I can use llvm/test/CodeGen/X86/win-funclet-cfi.ll 
> 
>  as a template and adjust it for the ObjC ARC case?

You could go that route, but I would probably start with simplified ObjC++ 
code, and iteratively modify that until you get the IR that has the funclets 
that you want to see. This is a decent starting template:

  void maythrow();
  void arcOpsInFunclet() {
try {
  maythrow();
}
catch (...) {
  // Do things that generate ARC intrinsics, probably set up an `id` 
variable.
}
  }

Maybe you could make the test plain ObjC, but I don't know it very well.

Lastly, I think the inliner needs to be taught that these intrinsics need to 
carry operand bundles, otherwise this problem will arise after optimization. 
The inliner has the same logic here:
https://github.com/llvm/llvm-project/blob/main/llvm/lib/Transforms/Utils/InlineFunction.cpp#L2311

The test case for this should be:

  struct Foo {
inline __attribute__((always_inline)) ~Foo() { /* ARC ops to inline */ }
  };
  void maythrow();
  void bar() {
Foo o;
maythrow();
  }




Comment at: llvm/lib/CodeGen/WinEHPrepare.cpp:966
 
-if (FuncletBundleOperand == FuncletPad)
+if (!FuncletPad || FuncletBundleOperand == FuncletPad)
   continue;

Is this change necessary? It seems like it shouldn't be after the clang and 
preisel pass changes.


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[PATCH] D124762: [WinEHPrepare] Avoid truncation of EH funclets with GNUstep ObjC runtime

[Stefan Gränitz via Phabricator via cfe-commits]

sgraenitz added a comment.

I guess testing must be split in two:

- Clang wants to make sure the "funclet" bundle operand gets emitted for ObjC 
ARC runtime calls on Windows. Maybe that fits into 
clang/test/CodeGenObjC/gnu-exceptions.m 
?
- LLVM wants to check that WinEHPrepare handles these runtime calls correctly. 
For that maybe I can use llvm/test/CodeGen/X86/win-funclet-cfi.ll 

 as a template and adjust it for the ObjC ARC case?


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[PATCH] D124762: [WinEHPrepare] Avoid truncation of EH funclets with GNUstep ObjC runtime

[Stefan Gränitz via Phabricator via cfe-commits]

sgraenitz created this revision.
sgraenitz added reviewers: rnk, theraven, DHowett-MSFT.
Herald added a subscriber: hiraditya.
Herald added a project: All.
sgraenitz requested review of this revision.
Herald added projects: clang, LLVM.
Herald added a subscriber: cfe-commits.

Unwinding ObjC code with automatic reference counting involves calls to 
intrinsics like `llvm.obj.retain` and `llvm.objc.destroyWeak`. Exception 
handling on Windows is based on funclets and WinEHPrepare only allows calls to 
`nounwind` intrinsics. This works just fine, except for ObjC `nounwind` 
intrinsics, because these are lowered into regular function calls in an earlier 
stage already (i.e. PreISelIntrinsicLoweringPass). Thus, WinEHPrepare 
accidentally drops them as implausible instructions and silently truncates 
certain funclets. Eventually, this causes crashes during unwinding on Windows 
with the GNUstep ObjC runtime: https://github.com/gnustep/libobjc2/issues/222

This patch forces the emission of a "funclet" bundle operand for calls to ObjC 
ARC intrinsics during codegen and lets PreISelIntrinsicLowering carry it over 
onto lowered replacement calls. This way all ObjC ARC calls survive 
WinEHPrepare through the FuncletBundleOperand check. The latter had to be 
adjusted in order to allow funclet pads to get optimized away.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D124762

Files:
  clang/lib/CodeGen/CGCall.cpp
  llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
  llvm/lib/CodeGen/WinEHPrepare.cpp


Index: llvm/lib/CodeGen/WinEHPrepare.cpp
===
--- llvm/lib/CodeGen/WinEHPrepare.cpp
+++ llvm/lib/CodeGen/WinEHPrepare.cpp
@@ -963,7 +963,7 @@
 if (auto BU = CB->getOperandBundle(LLVMContext::OB_funclet))
   FuncletBundleOperand = BU->Inputs.front();
 
-if (FuncletBundleOperand == FuncletPad)
+if (!FuncletPad || FuncletBundleOperand == FuncletPad)
   continue;
 
 // Skip call sites which are nounwind intrinsics or inline asm.
Index: llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
===
--- llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
+++ llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
@@ -107,7 +107,9 @@
 
 IRBuilder<> Builder(CI->getParent(), CI->getIterator());
 SmallVector Args(CI->args());
-CallInst *NewCI = Builder.CreateCall(FCache, Args);
+SmallVector BundleList;
+CI->getOperandBundlesAsDefs(BundleList);
+CallInst *NewCI = Builder.CreateCall(FCache, Args, BundleList);
 NewCI->setName(CI->getName());
 
 // Try to set the most appropriate TailCallKind based on both the current
Index: clang/lib/CodeGen/CGCall.cpp
===
--- clang/lib/CodeGen/CGCall.cpp
+++ clang/lib/CodeGen/CGCall.cpp
@@ -25,11 +25,13 @@
 #include "clang/AST/DeclCXX.h"
 #include "clang/AST/DeclObjC.h"
 #include "clang/Basic/CodeGenOptions.h"
+#include "clang/Basic/ObjCRuntime.h"
 #include "clang/Basic/TargetBuiltins.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/CodeGen/CGFunctionInfo.h"
 #include "clang/CodeGen/SwiftCallingConv.h"
 #include "llvm/ADT/StringExtras.h"
+#include "llvm/Analysis/ObjCARCInstKind.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/IR/Assumptions.h"
 #include "llvm/IR/Attributes.h"
@@ -4470,11 +4472,30 @@
 return BundleList;
 
   // Skip intrinsics which cannot throw.
+  bool InsertFuncletOp = true;
   auto *CalleeFn = dyn_cast(Callee->stripPointerCasts());
   if (CalleeFn && CalleeFn->isIntrinsic() && CalleeFn->doesNotThrow())
-return BundleList;
+InsertFuncletOp = false;
+
+  // ObjC ARC intrinics are lowered in PreISelIntrinsicLowering. Thus,
+  // WinEHPrepare will see them as regular calls. We need to set the funclet
+  // operand explicitly in this case to avoid accidental truncation of EH
+  // funclets on Windows.
+  using namespace llvm::objcarc;
+  if (GetFunctionClass(CalleeFn) != ARCInstKind::None) {
+assert(CalleeFn->isIntrinsic() && CalleeFn->doesNotThrow() &&
+   "Right now these are nounwind intrinsics");
+if (CGM.getTarget().getTriple().isOSWindows()) {
+  assert(CGM.getLangOpts().ObjCRuntime.getKind() == ObjCRuntime::GNUstep &&
+ "Only reproduced with GNUstep so far, but likely applies to other 
"
+ "ObjC runtimes on Windows");
+  InsertFuncletOp = true;
+}
+  }
+
+  if (InsertFuncletOp)
+BundleList.emplace_back("funclet", CurrentFuncletPad);
 
-  BundleList.emplace_back("funclet", CurrentFuncletPad);
   return BundleList;
 }
 


Index: llvm/lib/CodeGen/WinEHPrepare.cpp
===
--- llvm/lib/CodeGen/WinEHPrepare.cpp
+++ llvm/lib/CodeGen/WinEHPrepare.cpp
@@ -963,7 +963,7 @@
 if (auto BU = CB->getOperandBundle(LLVMContext::OB_funclet))
   FuncletBundleOperand =