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Current assert wiht /EHa with
A single unwind edge may only enter one EH pad
invoke void @llvm.seh.try.begin()
to label %invoke.cont1 unwind label %catch.dispatch2
IR:
%1 = catchpad within %0 [ptr null, i32 0, ptr null]
invoke void @llvm.seh.try.begin()
to label %invoke.cont5 unwind label %catch.dispatch2
The problem is the invoke to llvm.seh.try.begin() missing "funclet"
Accodring: https://llvm.org/docs/LangRef.html#ob-funclet
If any "funclet" EH pads have been entered but not exited (per the
description in the EH doc), it is undefined behavior to execute a
call or invoke.
To fix the problem, when emit seh_try_begin, call EmitSehScope,
instead of calling EmitRuntimeCallOrInvoke for proper "funclet"
gerenration.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D150340
Files:
clang/lib/CodeGen/CGCleanup.cpp
clang/lib/CodeGen/CGException.cpp
clang/lib/CodeGen/CodeGenFunction.h
clang/test/CodeGen/windows-seh-EHa-CppCatchDotDotDot.cpp
Index: clang/test/CodeGen/windows-seh-EHa-CppCatchDotDotDot.cpp
===================================================================
--- clang/test/CodeGen/windows-seh-EHa-CppCatchDotDotDot.cpp
+++ clang/test/CodeGen/windows-seh-EHa-CppCatchDotDotDot.cpp
@@ -9,11 +9,21 @@
// CHECK: %[[dst1:[0-9-]+]] = catchpad within %[[dst]] [ptr null, i32 0, ptr null]
// CHECK: "funclet"(token %[[dst1]])
+// CHECK: define dso_local void @"?bar@@YAXXZ
+// CHECK: invoke void @llvm.seh.try.begin()
+// CHECK: invoke void @_CxxThrowException
+// CHECK: %[[dst:[0-9-]+]] = catchpad within %0 [ptr null, i32 0, ptr null]
+// CHECK: invoke void @llvm.seh.try.begin() [ "funclet"(token %[[dst]]) ]
+
// CHECK: invoke void @llvm.seh.try.begin()
// CHECK: %[[src:[0-9-]+]] = load volatile i32, ptr %i
// CHECK-NEXT: invoke void @"?crash@@YAXH@Z"(i32 noundef %[[src]])
// CHECK: invoke void @llvm.seh.try.end()
+// CHECK: invoke void @llvm.seh.try.begin()
+// CHECK: invoke void @"?bar@@YAXXZ"()
+// CHECK: invoke void @llvm.seh.try.end()
+
// *****************************************************************************
// Abstract: Test CPP catch(...) under SEH -EHa option
@@ -46,6 +56,18 @@
}
}
+void bar() {
+ try {
+ throw 1;
+ } catch(...) {
+ try {
+ *NullPtr = 0;
+ } catch (...) {
+ throw 1;
+ }
+ }
+}
+
int main() {
for (int i = 0; i < 2; i++) {
__try {
@@ -54,5 +76,10 @@
printf(" Test CPP unwind: in except handler i = %d \n", i);
}
}
+ __try {
+ bar();
+ } __except (1) {
+ printf("Test CPP unwind: in except handler \n");
+ }
return 0;
}
Index: clang/lib/CodeGen/CodeGenFunction.h
===================================================================
--- clang/lib/CodeGen/CodeGenFunction.h
+++ clang/lib/CodeGen/CodeGenFunction.h
@@ -2933,6 +2933,7 @@
void EmitSehCppScopeEnd();
void EmitSehTryScopeBegin();
void EmitSehTryScopeEnd();
+ void EmitSehScope(llvm::FunctionCallee &SehCppScope);
llvm::Value *EmitLifetimeStart(llvm::TypeSize Size, llvm::Value *Addr);
void EmitLifetimeEnd(llvm::Value *Size, llvm::Value *Addr);
Index: clang/lib/CodeGen/CGException.cpp
===================================================================
--- clang/lib/CodeGen/CGException.cpp
+++ clang/lib/CodeGen/CGException.cpp
@@ -645,8 +645,10 @@
CatchScope->setHandler(I, CGM.getCXXABI().getCatchAllTypeInfo(), Handler);
// Under async exceptions, catch(...) need to catch HW exception too
// Mark scope with SehTryBegin as a SEH __try scope
- if (getLangOpts().EHAsynch)
- EmitRuntimeCallOrInvoke(getSehTryBeginFn(CGM));
+ if (getLangOpts().EHAsynch) {
+ llvm::FunctionCallee SehCppScope = getSehTryBeginFn(CGM);
+ EmitSehScope(SehCppScope);
+ }
}
}
}
Index: clang/lib/CodeGen/CGCleanup.cpp
===================================================================
--- clang/lib/CodeGen/CGCleanup.cpp
+++ clang/lib/CodeGen/CGCleanup.cpp
@@ -1328,18 +1328,16 @@
// Need to set "funclet" in OperandBundle properly for noThrow
// intrinsic (see CGCall.cpp)
-static void EmitSehScope(CodeGenFunction &CGF,
- llvm::FunctionCallee &SehCppScope) {
- llvm::BasicBlock *InvokeDest = CGF.getInvokeDest();
- assert(CGF.Builder.GetInsertBlock() && InvokeDest);
- llvm::BasicBlock *Cont = CGF.createBasicBlock("invoke.cont");
+void CodeGenFunction::EmitSehScope(llvm::FunctionCallee &SehCppScope) {
+ llvm::BasicBlock *InvokeDest = getInvokeDest();
+ assert(Builder.GetInsertBlock() && InvokeDest);
+ llvm::BasicBlock *Cont = createBasicBlock("invoke.cont");
SmallVector<llvm::OperandBundleDef, 1> BundleList =
- CGF.getBundlesForFunclet(SehCppScope.getCallee());
- if (CGF.CurrentFuncletPad)
- BundleList.emplace_back("funclet", CGF.CurrentFuncletPad);
- CGF.Builder.CreateInvoke(SehCppScope, Cont, InvokeDest, std::nullopt,
- BundleList);
- CGF.EmitBlock(Cont);
+ getBundlesForFunclet(SehCppScope.getCallee());
+ if (CurrentFuncletPad)
+ BundleList.emplace_back("funclet", CurrentFuncletPad);
+ Builder.CreateInvoke(SehCppScope, Cont, InvokeDest, std::nullopt, BundleList);
+ EmitBlock(Cont);
}
// Invoke a llvm.seh.scope.begin at the beginning of a CPP scope for -EHa
@@ -1349,7 +1347,7 @@
llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
llvm::FunctionCallee SehCppScope =
CGM.CreateRuntimeFunction(FTy, "llvm.seh.scope.begin");
- EmitSehScope(*this, SehCppScope);
+ EmitSehScope(SehCppScope);
}
// Invoke a llvm.seh.scope.end at the end of a CPP scope for -EHa
@@ -1360,7 +1358,7 @@
llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
llvm::FunctionCallee SehCppScope =
CGM.CreateRuntimeFunction(FTy, "llvm.seh.scope.end");
- EmitSehScope(*this, SehCppScope);
+ EmitSehScope(SehCppScope);
}
// Invoke a llvm.seh.try.begin at the beginning of a SEH scope for -EHa
@@ -1370,7 +1368,7 @@
llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
llvm::FunctionCallee SehCppScope =
CGM.CreateRuntimeFunction(FTy, "llvm.seh.try.begin");
- EmitSehScope(*this, SehCppScope);
+ EmitSehScope(SehCppScope);
}
// Invoke a llvm.seh.try.end at the end of a SEH scope for -EHa
@@ -1380,5 +1378,5 @@
llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
llvm::FunctionCallee SehCppScope =
CGM.CreateRuntimeFunction(FTy, "llvm.seh.try.end");
- EmitSehScope(*this, SehCppScope);
+ EmitSehScope(SehCppScope);
}
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