From: John McCall <rjmccall@apple.com>
Date: Wed, 11 Aug 2010 22:38:33 +0000 (+0000)
Subject: Revise r110163: don't mark weak functions nounwind, because the optimizer
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=b3a29f132794f67108bccc9c7cc3795365e8a965;p=clang

Revise r110163: don't mark weak functions nounwind, because the optimizer
treats that as a contract to be fulfilled by any replacements.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@110864 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/CodeGenFunction.cpp b/lib/CodeGen/CodeGenFunction.cpp
index 58d56ef0df..e5cfa624b2 100644
--- a/lib/CodeGen/CodeGenFunction.cpp
+++ b/lib/CodeGen/CodeGenFunction.cpp
@@ -315,6 +315,10 @@ void CodeGenFunction::EmitFunctionBody(FunctionArgList &Args) {
 /// non-existence of any throwing calls within it.  We believe this is
 /// lightweight enough to do at -O0.
 static void TryMarkNoThrow(llvm::Function *F) {
+  // LLVM treats 'nounwind' on a function as part of the type, so we
+  // can't do this on functions that can be overwritten.
+  if (F->mayBeOverridden()) return;
+
   for (llvm::Function::iterator FI = F->begin(), FE = F->end(); FI != FE; ++FI)
     for (llvm::BasicBlock::iterator
            BI = FI->begin(), BE = FI->end(); BI != BE; ++BI)
diff --git a/test/CodeGen/unwind-attr.c b/test/CodeGen/unwind-attr.c
index 459176cdf7..c588ca8e1b 100644
--- a/test/CodeGen/unwind-attr.c
+++ b/test/CodeGen/unwind-attr.c
@@ -15,3 +15,10 @@ int test0(void) {
 int test1(void) {
   return 0;
 }
+
+// <rdar://problem/8283071>: not for weak functions
+// CHECK:       define weak [[INT:i.*]] @test2() {
+// CHECK-NOEXC: define weak [[INT:i.*]] @test2() nounwind {
+__attribute__((weak)) int test2(void) {
+  return 0;
+}