[OPENMP] Fix crash on code emitting if errors are found.

[ABataev]

Summary

Codegen for threadprivate variables (and in some other cases) may cause crash of the compiler if some diagnostic is produced later. This happens because some of the autogenerated globals are not removed from InternalVars StringMap when llvm::Module is reset.

[rjmccall]

LGTM.

cfe/trunk/lib/CodeGen/CGOpenMPRuntime.h

class CGOpenMPRuntime {
   /// reference to the existing copy is returned.
   /// \param CriticalName Name of the critical region.
   ///
   llvm::Value *getCriticalRegionLock(StringRef CriticalName);
 
 public:
   explicit CGOpenMPRuntime(CodeGenModule &CGM);
   virtual ~CGOpenMPRuntime() {}
+  virtual void clear();
 
   /// \brief Emits outlined function for the specified OpenMP directive \a D.
   /// This outlined function has type void(*)(kmp_int32 *ThreadID, kmp_int32
   /// BoundID, struct context_vars*).
   /// \param D OpenMP directive.
   /// \param ThreadIDVar Variable for thread id in the current OpenMP region.
   ///
   virtual llvm::Value *emitOutlinedFunction(const OMPExecutableDirective &D,

cfe/trunk/lib/CodeGen/CGOpenMPRuntime.cpp

IdentTy = llvm::StructType::create(
       CGM.Int8PtrTy /* psource */, nullptr);
   // Build void (*kmpc_micro)(kmp_int32 *global_tid, kmp_int32 *bound_tid,...)
   llvm::Type *MicroParams[] = {llvm::PointerType::getUnqual(CGM.Int32Ty),
                                llvm::PointerType::getUnqual(CGM.Int32Ty)};
   Kmpc_MicroTy = llvm::FunctionType::get(CGM.VoidTy, MicroParams, true);
   KmpCriticalNameTy = llvm::ArrayType::get(CGM.Int32Ty, /*NumElements*/ 8);
 }
 
+void CGOpenMPRuntime::clear() {
+  InternalVars.clear();
+}
+
 llvm::Value *
 CGOpenMPRuntime::emitOutlinedFunction(const OMPExecutableDirective &D,
                                       const VarDecl *ThreadIDVar) {
   assert(ThreadIDVar->getType()->isPointerType() &&
          "thread id variable must be of type kmp_int32 *");
   const CapturedStmt *CS = cast<CapturedStmt>(D.getAssociatedStmt());
   CodeGenFunction CGF(CGM, true);
   CGOpenMPOutlinedRegionInfo CGInfo(D, *CS, ThreadIDVar);

cfe/trunk/lib/CodeGen/CodeGenModule.cpp

for (std::vector<GlobalDecl>::iterator I = Aliases.begin(),
     auto *Alias = cast<llvm::GlobalAlias>(Entry);
     Alias->replaceAllUsesWith(llvm::UndefValue::get(Alias->getType()));
     Alias->eraseFromParent();
   }
 }
 
 void CodeGenModule::clear() {
   DeferredDeclsToEmit.clear();
+  if (OpenMPRuntime)
+    OpenMPRuntime->clear();
 }
 
 void InstrProfStats::reportDiagnostics(DiagnosticsEngine &Diags,
                                        StringRef MainFile) {
   if (!hasDiagnostics())
     return;
   if (VisitedInMainFile > 0 && VisitedInMainFile == MissingInMainFile) {
     if (MainFile.empty())

cfe/trunk/test/OpenMP/threadprivate_messages.cpp

-// RUN: %clang_cc1 -triple x86_64-apple-macos10.7.0 -verify -fopenmp=libiomp5 -ferror-limit 100 %s
+// RUN: %clang_cc1 -triple x86_64-apple-macos10.7.0 -verify -fopenmp=libiomp5 -ferror-limit 100 -emit-llvm -o - %s
 
 #pragma omp threadprivate // expected-error {{expected '(' after 'threadprivate'}}
 #pragma omp threadprivate( // expected-error {{expected identifier}} expected-error {{expected ')'}} expected-note {{to match this '('}}
 #pragma omp threadprivate() // expected-error {{expected identifier}}
 #pragma omp threadprivate(1) // expected-error {{expected unqualified-id}}
 struct CompleteSt{
  int a;
 };