[PATCH] D157566: [SEH] fix assertion when -fasy-exceptions is used.
Jennifer Yu via Phabricator via cfe-commits
cfe-commits at lists.llvm.org
Wed Aug 9 17:57:45 PDT 2023
jyu2 created this revision.
jyu2 added reviewers: asmith, tentzen, rnk, efriedma, pengfei.
jyu2 added a project: clang.
Herald added a project: All.
jyu2 requested review of this revision.
The assertion only happens with use of -fasy-exception without
-fexcessions.
The assertion appen during the call to generate SehScopeBegin(), where
assert with:
assert(CGF.Builder.GetInsertBlock() && InvokeDest);
InvokeDest is null. Because exceptions are disabled, and SEH is not
in use.
The fix is before call EmitSehCppScopeBegin check getInvokeDest(),
to avoid assert during the emit llvm.seh.scope.begin()
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D157566
Files:
clang/lib/CodeGen/CGCleanup.cpp
clang/test/CodeGen/windows-seh-async-exceptions.cpp
Index: clang/test/CodeGen/windows-seh-async-exceptions.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGen/windows-seh-async-exceptions.cpp
@@ -0,0 +1,23 @@
+// RUN: %clang_cc1 -triple x86_64-windows -fasync-exceptions -x c++ \
+// RUN: -emit-llvm %s -o -| FileCheck %s
+
+
+extern "C" int printf(const char*,...);
+class PrintfArg
+{
+public:
+ PrintfArg();
+ PrintfArg(const char* s);
+
+ // compiler crash fixed if this destructor removed
+ ~PrintfArg() {int x; printf("ddd\n"); }
+};
+
+void devif_Warning(const char* fmt, PrintfArg arg1 = PrintfArg());
+// CHECK-NOT: invoke void @llvm.seh.scope.begin()
+// CHECK-NOT: invoke void @llvm.seh.scope.end()
+unsigned myfunc(unsigned index)
+{
+ devif_Warning("");
+ return 0;
+}
Index: clang/lib/CodeGen/CGCleanup.cpp
===================================================================
--- clang/lib/CodeGen/CGCleanup.cpp
+++ clang/lib/CodeGen/CGCleanup.cpp
@@ -207,8 +207,13 @@
Scope->setLifetimeMarker();
// With Windows -EHa, Invoke llvm.seh.scope.begin() for EHCleanup
+ // If exceptions are disabled/ignored and SEH is not in use, then there is no
+ // invoke destination. SEH "works" even if exceptions are off. In practice,
+ // this means that C++ destructors and other EH cleanups don't run, which is
+ // consistent with MSVC's behavior, except in the presence of -EHa.
+ // Check getInvokeDest() to generate llvm.seh.scope.begin() as needed.
if (CGF->getLangOpts().EHAsynch && IsEHCleanup && !IsLifetimeMarker &&
- CGF->getTarget().getCXXABI().isMicrosoft())
+ CGF->getTarget().getCXXABI().isMicrosoft() && CGF->getInvokeDest())
CGF->EmitSehCppScopeBegin();
return Scope->getCleanupBuffer();
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