DO NOT MERGE, cherry-pick from master

Fix .rs.dtor scoping bug.

BUG=5267595

This change makes sure to scope any helper variables (like rsIntIter) to the
enclosing function (and not make them global). Prior to this change, if an
array iterator was created, it would be marked as a global symbol. The
libbcc library then sometimes removed this global as it was not able to
determine that it was actually used (.rs.dtor is not guaranteed to be called).
A fix should be made to libbcc as well, but the proper fix for llvm-rs-cc is
to scope any helper variable declarations to the calling function.

Change-Id: Ia46654cb0a114f6f5495e32ad1508d7d01e2084b

2 files changed, 20 insertions, 12 deletions

diff --git a/slang_rs_object_ref_count.cpp b/slang_rs_object_ref_count.cpp
index e35c677..88ffc62 100644
--- a/slang_rs_object_ref_count.cpp
+++ b/slang_rs_object_ref_count.cpp
@@ -1230,7 +1230,7 @@ void RSObjectRefCount::Scope::InsertLocalVarDestructors() {
         I != E;
         I++) {
     clang::VarDecl *VD = *I;
-    clang::Stmt *RSClearObjectCall = ClearRSObject(VD);
+    clang::Stmt *RSClearObjectCall = ClearRSObject(VD, VD->getDeclContext());
     if (RSClearObjectCall) {
       DestructorVisitor DV((*mRSO.begin())->getASTContext(),
                            mCS,
@@ -1243,10 +1243,11 @@ void RSObjectRefCount::Scope::InsertLocalVarDestructors() {
   return;
 }
 
-clang::Stmt *RSObjectRefCount::Scope::ClearRSObject(clang::VarDecl *VD) {
+clang::Stmt *RSObjectRefCount::Scope::ClearRSObject(
+    clang::VarDecl *VD,
+    clang::DeclContext *DC) {
   slangAssert(VD);
   clang::ASTContext &C = VD->getASTContext();
-  clang::DeclContext *DC = VD->getDeclContext();
   clang::SourceLocation Loc = VD->getLocation();
   clang::SourceLocation StartLoc = VD->getInnerLocStart();
   const clang::Type *T = RSExportType::GetTypeOfDecl(VD);
@@ -1494,6 +1495,13 @@ clang::FunctionDecl *RSObjectRefCount::CreateStaticGlobalDtor() {
   clang::DeclContext *DC = mCtx.getTranslationUnitDecl();
   clang::SourceLocation loc;
 
+  llvm::StringRef SR(".rs.dtor");
+  clang::IdentifierInfo &II = mCtx.Idents.get(SR);
+  clang::DeclarationName N(&II);
+  clang::FunctionProtoType::ExtProtoInfo EPI;
+  clang::QualType T = mCtx.getFunctionType(mCtx.VoidTy, NULL, 0, EPI);
+  clang::FunctionDecl *FD = NULL;
+
   // Generate rsClearObject() call chains for every global variable
   // (whether static or extern).
   std::list<clang::Stmt *> StmtList;
@@ -1502,7 +1510,13 @@ clang::FunctionDecl *RSObjectRefCount::CreateStaticGlobalDtor() {
     clang::VarDecl *VD = llvm::dyn_cast<clang::VarDecl>(*I);
     if (VD) {
       if (CountRSObjectTypes(mCtx, VD->getType().getTypePtr(), loc)) {
-        clang::Stmt *RSClearObjectCall = Scope::ClearRSObject(VD);
+        if (!FD) {
+          // Only create FD if we are going to use it.
+          FD = clang::FunctionDecl::Create(mCtx, DC, loc, loc, N, T, NULL);
+        }
+        // Make sure to create any helpers within the function's DeclContext,
+        // not the one associated with the global translation unit.
+        clang::Stmt *RSClearObjectCall = Scope::ClearRSObject(VD, FD);
         StmtList.push_back(RSClearObjectCall);
       }
     }
@@ -1513,13 +1527,6 @@ clang::FunctionDecl *RSObjectRefCount::CreateStaticGlobalDtor() {
     return NULL;
   }
 
-  llvm::StringRef SR(".rs.dtor");
-  clang::IdentifierInfo &II = mCtx.Idents.get(SR);
-  clang::DeclarationName N(&II);
-  clang::FunctionProtoType::ExtProtoInfo EPI;
-  clang::QualType T = mCtx.getFunctionType(mCtx.VoidTy, NULL, 0, EPI);
-  clang::FunctionDecl *FD = clang::FunctionDecl::Create(mCtx, DC, loc, loc, N,
-                                                        T, NULL);
   clang::CompoundStmt *CS = BuildCompoundStmt(mCtx, StmtList, loc);
 
   FD->setBody(CS);
diff --git a/slang_rs_object_ref_count.h b/slang_rs_object_ref_count.h
index 15be35f..1e87ca1 100644
--- a/slang_rs_object_ref_count.h
+++ b/slang_rs_object_ref_count.h
@@ -68,7 +68,8 @@ class RSObjectRefCount : public clang::StmtVisitor<RSObjectRefCount> {
 
     void InsertLocalVarDestructors();
 
-    static clang::Stmt *ClearRSObject(clang::VarDecl *VD);
+    static clang::Stmt *ClearRSObject(clang::VarDecl *VD,
+                                      clang::DeclContext *DC);
   };
 
   clang::ASTContext &mCtx;