commit bfcc823a5c53dabab8cfc842bfea70e2b69cdee0
author Douglas Gregor <dgregor@apple.com> Sat May 15 17:55:51 2010 +0000
committer Douglas Gregor <dgregor@apple.com> Sat May 15 17:55:51 2010 +0000
tree b3daea2b733e9d363aca8ea272dacf787d9af732
parent 72bf425fab902f5fd6114b630b8dc3dc0e1de1a8

When initializing thread-safe statics, put the call to
__cxa_guard_abort along the exceptional edge into (in effect) a nested
"try" that rethrows after aborting. Fixes PR7144 and the remaining
Boost.ProgramOptions failures.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@103880 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CGDeclCXX.cpp

diff --git a/lib/CodeGen/CGDeclCXX.cpp b/lib/CodeGen/CGDeclCXX.cpp
index 036be92..cbee247 100644
--- a/lib/CodeGen/CGDeclCXX.cpp
+++ b/lib/CodeGen/CGDeclCXX.cpp
@@ -321,7 +321,11 @@
 
   EmitBlock(InitCheckBlock);
 
-  if (ThreadsafeStatics) {
+  // Variables used when coping with thread-safe statics and exceptions.
+  llvm::BasicBlock *SavedLandingPad = 0;
+  llvm::BasicBlock *Abort = 0;
+  
+  if (ThreadsafeStatics) {    
     // Call __cxa_guard_acquire.
     V = Builder.CreateCall(getGuardAcquireFn(*this), GuardVariable);
                
@@ -330,14 +334,13 @@
     Builder.CreateCondBr(Builder.CreateIsNotNull(V, "tobool"),
                          InitBlock, EndBlock);
   
-    EmitBlock(InitBlock);
-
     if (Exceptions) {
-      EHCleanupBlock Cleanup(*this);
-    
-      // Call __cxa_guard_abort.
-      Builder.CreateCall(getGuardAbortFn(*this), GuardVariable);
+      SavedLandingPad = getInvokeDest();
+      Abort = createBasicBlock("guard.abort");
+      setInvokeDest(Abort);
     }
+    
+    EmitBlock(InitBlock);
   }
 
   if (D.getType()->isReferenceType()) {
@@ -353,7 +356,7 @@
 
   if (ThreadsafeStatics) {
     // Call __cxa_guard_release.
-    Builder.CreateCall(getGuardReleaseFn(*this), GuardVariable);
+    Builder.CreateCall(getGuardReleaseFn(*this), GuardVariable);    
   } else {
     llvm::Value *One = 
       llvm::ConstantInt::get(llvm::Type::getInt8Ty(VMContext), 1);
@@ -364,5 +367,20 @@
   if (!D.getType()->isReferenceType())
     EmitDeclDestroy(*this, D, GV);
   
+  if (ThreadsafeStatics && Exceptions) {
+    // If an exception is thrown during initialization, call __cxa_guard_abort
+    // along the exceptional edge.
+    EmitBranch(EndBlock);
+    
+    EmitBlock(Abort);
+    
+    // Call __cxa_guard_abort along the exceptional edge.
+    Builder.CreateCall(getGuardAbortFn(*this), GuardVariable);
+    setInvokeDest(SavedLandingPad);
+    
+    // Rethrow the current exception.
+    EmitRethrow();
+  }    
+  
   EmitBlock(EndBlock);
 }

lib/CodeGen/CGException.cpp

diff --git a/lib/CodeGen/CGException.cpp b/lib/CodeGen/CGException.cpp
index c1d05bf..76a57d6 100644
--- a/lib/CodeGen/CGException.cpp
+++ b/lib/CodeGen/CGException.cpp
@@ -239,19 +239,23 @@
   }
 }
 
+void CodeGenFunction::EmitRethrow() {
+  if (getInvokeDest()) {
+    llvm::BasicBlock *Cont = createBasicBlock("invoke.cont");
+    Builder.CreateInvoke(getReThrowFn(*this), Cont, getInvokeDest())
+    ->setDoesNotReturn();
+    EmitBlock(Cont);
+  } else
+    Builder.CreateCall(getReThrowFn(*this))->setDoesNotReturn();
+  Builder.CreateUnreachable();
+  
+  // Clear the insertion point to indicate we are in unreachable code.
+  Builder.ClearInsertionPoint();
+}
+
 void CodeGenFunction::EmitCXXThrowExpr(const CXXThrowExpr *E) {
   if (!E->getSubExpr()) {
-    if (getInvokeDest()) {
-      llvm::BasicBlock *Cont = createBasicBlock("invoke.cont");
-      Builder.CreateInvoke(getReThrowFn(*this), Cont, getInvokeDest())
-        ->setDoesNotReturn();
-      EmitBlock(Cont);
-    } else
-      Builder.CreateCall(getReThrowFn(*this))->setDoesNotReturn();
-    Builder.CreateUnreachable();
-
-    // Clear the insertion point to indicate we are in unreachable code.
-    Builder.ClearInsertionPoint();
+    EmitRethrow();
     return;
   }
 
@@ -562,6 +566,7 @@
         // FIXME: we need to do this sooner so that the EH region for the
         // cleanup doesn't start until after the ctor completes, use a decl
         // init?
+        // FIXME: Alternatively, can we just elide this copy entirely?
         CopyObject(*this, CatchParam->getType().getNonReferenceType(),
                    WasPointer, WasPointerReference, ExcObject,
                    GetAddrOfLocalVar(CatchParam));

lib/CodeGen/CodeGenFunction.h

diff --git a/lib/CodeGen/CodeGenFunction.h b/lib/CodeGen/CodeGenFunction.h
index 151c13c..9761fa0 100644
--- a/lib/CodeGen/CodeGenFunction.h
+++ b/lib/CodeGen/CodeGenFunction.h
@@ -1258,7 +1258,8 @@
                                     bool IsInitializer = false);
 
   void EmitCXXThrowExpr(const CXXThrowExpr *E);
-
+  void EmitRethrow();
+  
   //===--------------------------------------------------------------------===//
   //                             Internal Helpers
   //===--------------------------------------------------------------------===//