[llvm] r181838 - GlobalOpt: fix an issue where CXAAtExitFn points to a deleted function.

[Manman Ren]

Author: mren
Date: Tue May 14 16:52:44 2013
New Revision: 181838

URL: http://llvm.org/viewvc/llvm-project?rev=181838&view=rev
Log:
GlobalOpt: fix an issue where CXAAtExitFn points to a deleted function.

CXAAtExitFn was set outside a loop and before optimizations where functions
can be deleted. This patch will set CXAAtExitFn inside the loop and after
optimizations.

Seg fault when running LTO because of accesses to a deleted function.
rdar://problem/13838828

Added:
    llvm/trunk/test/Transforms/GlobalOpt/atexit.ll
Modified:
    llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp

Modified: llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp?rev=181838&r1=181837&r2=181838&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp Tue May 14 16:52:44 2013
@@ -3323,8 +3323,6 @@ bool GlobalOpt::runOnModule(Module &M) {
   // Try to find the llvm.globalctors list.
   GlobalVariable *GlobalCtors = FindGlobalCtors(M);
 
-  Function *CXAAtExitFn = FindCXAAtExit(M, TLI);
-
   bool LocalChange = true;
   while (LocalChange) {
     LocalChange = false;
@@ -3342,7 +3340,9 @@ bool GlobalOpt::runOnModule(Module &M) {
     // Resolve aliases, when possible.
     LocalChange |= OptimizeGlobalAliases(M);
 
-    // Try to remove trivial global destructors.
+    // Try to remove trivial global destructors if they are not removed
+    // already.
+    Function *CXAAtExitFn = FindCXAAtExit(M, TLI);
     if (CXAAtExitFn)
       LocalChange |= OptimizeEmptyGlobalCXXDtors(CXAAtExitFn);
 

Added: llvm/trunk/test/Transforms/GlobalOpt/atexit.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GlobalOpt/atexit.ll?rev=181838&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/GlobalOpt/atexit.ll (added)
+++ llvm/trunk/test/Transforms/GlobalOpt/atexit.ll Tue May 14 16:52:44 2013
@@ -0,0 +1,6 @@
+; RUN: opt < %s -globalopt -S | FileCheck %s
+
+; CHECK: ModuleID
+define internal hidden i32 @__cxa_atexit(void (i8*)* nocapture %func, i8* nocapture %arg, i8* nocapture %dso_handle) nounwind readnone optsize noimplicitfloat {
+  unreachable
+}