2 files changed, 56 insertions, 0 deletions

diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index 6c9999df24..a74f0578a5 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -63,6 +63,7 @@ void CodeGenModule::Release() {
   EmitCtorList(GlobalCtors, "llvm.global_ctors");
   EmitCtorList(GlobalDtors, "llvm.global_dtors");
   EmitAnnotations();
+  BindRuntimeFunctions();
   // Run the verifier to check that the generated code is consistent.
   if (verifyModule(TheModule, llvm::PrintMessageAction)) {
     TheModule.dump();
@@ -70,6 +71,38 @@ void CodeGenModule::Release() {
   }
 }
 
+void CodeGenModule::BindRuntimeFunctions() {
+  // Deal with protecting runtime function names.
+  for (unsigned i = 0, e = RuntimeFunctions.size(); i < e; ++i) {
+    llvm::Function *Fn = RuntimeFunctions[i].first;
+    const std::string &Name = RuntimeFunctions[i].second;
+    
+    // See if there is a conflict against a function.
+    llvm::Function *Conflict = TheModule.getFunction(Name);
+    if (Conflict) {
+      // Decide which version to take. If the conflict is a definition
+      // we are forced to take that, otherwise assume the runtime
+      // knows best.
+      if (!Conflict->isDeclaration()) {
+        llvm::Value *Casted = 
+          llvm::ConstantExpr::getBitCast(Conflict, Fn->getType());
+        Fn->replaceAllUsesWith(Casted);
+        Fn->eraseFromParent();
+      } else {
+        Fn->takeName(Conflict);
+        llvm::Value *Casted = 
+          llvm::ConstantExpr::getBitCast(Fn, Conflict->getType());
+        Conflict->replaceAllUsesWith(Casted);
+        Conflict->eraseFromParent();
+      }
+    } else {
+      // FIXME: There still may be conflicts with aliases and
+      // variables. 
+      Fn->setName(Name);
+    }
+  }
+}
+
 /// ErrorUnsupported - Print out an error that codegen doesn't support the
 /// specified stmt yet.
 void CodeGenModule::ErrorUnsupported(const Stmt *S, const char *Type,
@@ -655,6 +688,16 @@ void CodeGenModule::EmitGlobalFunctionDefinition(const FunctionDecl *D) {
   }
 }
 
+llvm::Function *
+CodeGenModule::CreateRuntimeFunction(const llvm::FunctionType *FTy,
+                                     const std::string &Name) {
+  llvm::Function *Fn = llvm::Function::Create(FTy, 
+                                              llvm::Function::ExternalLinkage,
+                                              "", &TheModule);
+  RuntimeFunctions.push_back(std::make_pair(Fn, Name));
+  return Fn;
+}
+
 void CodeGenModule::UpdateCompletedType(const TagDecl *TD) {
   // Make sure that this type is translated.
   Types.UpdateCompletedType(TD);
diff --git a/lib/CodeGen/CodeGenModule.h b/lib/CodeGen/CodeGenModule.h
index 0a4a78d33c..6a201be376 100644
--- a/lib/CodeGen/CodeGenModule.h
+++ b/lib/CodeGen/CodeGenModule.h
@@ -73,6 +73,12 @@ class CodeGenModule {
   llvm::Function *MemMoveFn;
   llvm::Function *MemSetFn;
 
+  /// RuntimeFunctions - List of runtime functions whose names must be
+  /// protected from introducing conflicts. These functions should be
+  /// created unnamed, we will name them and patch up conflicts when
+  /// we release the module.
+  std::vector< std::pair<llvm::Function*, std::string> > RuntimeFunctions;
+
   /// GlobalDeclMap - Mapping of decl names global variables we have
   /// already emitted. Note that the entries in this map are the
   /// actual globals and therefore may not be of the same type as the
@@ -195,6 +201,11 @@ public:
 
   void AddAnnotation(llvm::Constant *C) { Annotations.push_back(C); }
 
+  /// CreateRuntimeFunction - Create a new runtime function whose name
+  /// must be protected from collisions.
+  llvm::Function *CreateRuntimeFunction(const llvm::FunctionType *Ty, 
+                                        const std::string &Name);
+
   void UpdateCompletedType(const TagDecl *D);
   llvm::Constant *EmitConstantExpr(const Expr *E, CodeGenFunction *CGF = 0);
   llvm::Constant *EmitAnnotateAttr(llvm::GlobalValue *GV,
@@ -263,6 +274,8 @@ private:
   void EmitAliases(void);
   void EmitAnnotations(void);
   void EmitStatics(void);
+
+  void BindRuntimeFunctions();
 };
 }  // end namespace CodeGen
 }  // end namespace clang