[CodeGen] Make __clang_call_terminate have an unwind table entry

This enables unwinders to step past that frame on architectures that don't use DWARF unwinding (such as armv7), e.g. when debugging. The problem should theoretically be architecture-agnostic, but according to https://discourse.llvm.org/t/51633/2 it gets masked on architectures that use DWARF unwind info. Fixes #40696 Reviewed By: efriedma, rnk Differential Revision: https://reviews.llvm.org/D151393
llvm · May 25, 2023 · 8f7b51e · 8f7b51e
1 parent 023504f
commit 8f7b51e
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diff --git a/clang/lib/CodeGen/ItaniumCXXABI.cpp b/clang/lib/CodeGen/ItaniumCXXABI.cpp
@@ -4689,6 +4689,7 @@ static llvm::FunctionCallee getClangCallTerminateFn(CodeGenModule &CGM) {
       cast<llvm::Function>(fnRef.getCallee()->stripPointerCasts());
   if (fn->empty()) {
     CGM.SetLLVMFunctionAttributes(GlobalDecl(), FI, fn, /*IsThunk=*/false);
+    CGM.SetLLVMFunctionAttributesForDefinition(nullptr, fn);
     fn->setDoesNotThrow();
     fn->setDoesNotReturn();
 

diff --git a/clang/test/CodeGenCXX/clang-call-terminate.uwtable.cpp b/clang/test/CodeGenCXX/clang-call-terminate.uwtable.cpp
@@ -0,0 +1,15 @@
+// RUN: %clang_cc1 -triple=x86_64-linux-gnu -fexceptions -fcxx-exceptions -emit-llvm -o - %s | \
+// RUN:   FileCheck --check-prefixes=CHECK,NOUNWIND %s
+// RUN: %clang_cc1 -triple=x86_64-linux-gnu -fexceptions -fcxx-exceptions -funwind-tables=1 -emit-llvm -o - %s | \
+// RUN:   FileCheck --check-prefixes=CHECK,SYNCUNWIND %s
+// RUN: %clang_cc1 -triple=x86_64-linux-gnu -fexceptions -fcxx-exceptions -funwind-tables=2 -emit-llvm -o - %s | \
+// RUN:   FileCheck --check-prefixes=CHECK,ASYNCUNWIND %s
+
+void caller(void callback()) noexcept { callback(); }
+
+// CHECK: define {{.*}}void @__clang_call_terminate({{[^)]*}}) #[[#ATTRNUM:]]
+// CHECK: attributes #[[#ATTRNUM]] = {
+// NOUNWIND-NOT: uwtable
+// NOUNWIND-SAME: }
+// SYNCUNWIND-SAME: uwtable(sync)
+// ASYNCUNWIND-SAME: uwtable{{ }}