From 29ac59f25cae74970570bea70f626bf8cd13fb08 Mon Sep 17 00:00:00 2001
From: Daniel Dunbar <daniel@zuster.org>
Date: Tue, 11 Nov 2008 04:34:23 +0000
Subject: [PATCH] Add CodeGenFunction::EmitDummyBlock for marking places where
 we make "dummy" blocks (blocks just used to make sure we have a place to dump
 code to).

llvm-svn: 59022
---
 clang/lib/CodeGen/CGObjCMac.cpp     |  2 +-
 clang/lib/CodeGen/CGStmt.cpp        | 16 ++++++++++------
 clang/lib/CodeGen/CodeGenFunction.h |  5 +++++
 3 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/clang/lib/CodeGen/CGObjCMac.cpp b/clang/lib/CodeGen/CGObjCMac.cpp
index 34f995225285..903e92dfc2df 100644
--- a/clang/lib/CodeGen/CGObjCMac.cpp
+++ b/clang/lib/CodeGen/CGObjCMac.cpp
@@ -1717,7 +1717,7 @@ void CGObjCMac::EmitThrowStmt(CodeGen::CodeGenFunction &CGF,
   
   CGF.Builder.CreateCall(ObjCTypes.ExceptionThrowFn, ExceptionAsObject);
   CGF.Builder.CreateUnreachable();
-  CGF.EmitBlock(CGF.createBasicBlock("bb"));
+  CGF.EmitDummyBlock();
 }
 
 void CodeGenFunction::EmitJumpThroughFinally(ObjCEHEntry *E,
diff --git a/clang/lib/CodeGen/CGStmt.cpp b/clang/lib/CodeGen/CGStmt.cpp
index 9d6a79b58429..82c39208a42a 100644
--- a/clang/lib/CodeGen/CGStmt.cpp
+++ b/clang/lib/CodeGen/CGStmt.cpp
@@ -167,6 +167,10 @@ void CodeGenFunction::EmitBlock(llvm::BasicBlock *BB) {
   Builder.SetInsertPoint(BB);
 }
 
+void CodeGenFunction::EmitDummyBlock() {
+  EmitBlock(createBasicBlock());
+}
+
 void CodeGenFunction::EmitLabel(const LabelStmt &S) {
   llvm::BasicBlock *NextBB = getBasicBlockForLabel(&S);
   EmitBlock(NextBB);
@@ -189,7 +193,7 @@ void CodeGenFunction::EmitGotoStmt(const GotoStmt &S) {
   
   // Emit a block after the branch so that dead code after a goto has some place
   // to go.
-  Builder.SetInsertPoint(createBasicBlock("", CurFn));
+  EmitDummyBlock();
 }
 
 void CodeGenFunction::EmitIndirectGotoStmt(const IndirectGotoStmt &S) {
@@ -210,7 +214,7 @@ void CodeGenFunction::EmitIndirectGotoStmt(const IndirectGotoStmt &S) {
 
   // Emit a block after the branch so that dead code after a goto has some place
   // to go.
-  Builder.SetInsertPoint(createBasicBlock("", CurFn));
+  EmitDummyBlock();
 }
 
 void CodeGenFunction::EmitIfStmt(const IfStmt &S) {
@@ -433,7 +437,7 @@ void CodeGenFunction::EmitReturnOfRValue(RValue RV, QualType Ty) {
 
   // Emit a block after the branch so that dead code after a return has some
   // place to go.
-  EmitBlock(createBasicBlock());
+  EmitDummyBlock();
 }
 
 /// EmitReturnStmt - Note that due to GCC extensions, this can have an operand
@@ -473,7 +477,7 @@ void CodeGenFunction::EmitReturnStmt(const ReturnStmt &S) {
   
   // Emit a block after the branch so that dead code after a return has some
   // place to go.
-  EmitBlock(createBasicBlock());
+  EmitDummyBlock();
 }
 
 void CodeGenFunction::EmitDeclStmt(const DeclStmt &S) {
@@ -487,7 +491,7 @@ void CodeGenFunction::EmitBreakStmt() {
 
   llvm::BasicBlock *Block = BreakContinueStack.back().BreakBlock;
   Builder.CreateBr(Block);
-  EmitBlock(createBasicBlock());
+  EmitDummyBlock();
 }
 
 void CodeGenFunction::EmitContinueStmt() {
@@ -495,7 +499,7 @@ void CodeGenFunction::EmitContinueStmt() {
 
   llvm::BasicBlock *Block = BreakContinueStack.back().ContinueBlock;
   Builder.CreateBr(Block);
-  EmitBlock(createBasicBlock());
+  EmitDummyBlock();
 }
 
 /// EmitCaseStmtRange - If case statement range is not too big then
diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index c9dcaa7d5502..a454cece4053 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -225,6 +225,11 @@ public:
   llvm::BasicBlock *getBasicBlockForLabel(const LabelStmt *S);
   
   void EmitBlock(llvm::BasicBlock *BB);
+
+  /// EmitDummyBlock - Emit a new block which will never be branched
+  /// to. This is used to satisfy the invariant that codegen always
+  /// has an active unterminated block to dump code into.
+  void EmitDummyBlock();
   
   /// ErrorUnsupported - Print out an error that codegen doesn't support the
   /// specified stmt yet.