Revert r151638 because it causes assertion hit on PCH creation for Cocoa.h

Original log:
---------------------
Correctly track tags and enum members defined in the prototype of a function, and ensure they are properly scoped.

This fixes code such as:

enum e {x, y};
int f(enum {y, x} n) {
 return 0;
}

This finally fixes PR5464 and PR5477.
---------------------

I also reverted r151641 which was enhancement on top of r151638.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@151667 91177308-0d34-0410-b5e6-96231b3b80d8

7 files changed, 3 insertions, 98 deletions

diff --git a/lib/AST/Decl.cpp b/lib/AST/Decl.cpp
index bd7579996f..433ce100cf 100644
--- a/lib/AST/Decl.cpp
+++ b/lib/AST/Decl.cpp
@@ -1847,16 +1847,6 @@ void FunctionDecl::setParams(ASTContext &C,
   }
 }
 
-void FunctionDecl::setDeclsInPrototypeScope(llvm::ArrayRef<NamedDecl *> NewDecls) {
-  assert(DeclsInPrototypeScope.empty() && "Already has prototype decls!");
-
-  if (!NewDecls.empty()) {
-    NamedDecl **A = new (getASTContext()) NamedDecl*[NewDecls.size()];
-    std::copy(NewDecls.begin(), NewDecls.end(), A);
-    DeclsInPrototypeScope = llvm::ArrayRef<NamedDecl*>(A, NewDecls.size());
-  }
-}
-
 /// getMinRequiredArguments - Returns the minimum number of arguments
 /// needed to call this function. This may be fewer than the number of
 /// function parameters, if some of the parameters have default
diff --git a/lib/AST/DumpXML.cpp b/lib/AST/DumpXML.cpp
index b180e808ab..b4038ddaf9 100644
--- a/lib/AST/DumpXML.cpp
+++ b/lib/AST/DumpXML.cpp
@@ -497,10 +497,6 @@ struct XMLDumper : public XMLDeclVisitor<XMLDumper>,
     for (FunctionDecl::param_iterator
            I = D->param_begin(), E = D->param_end(); I != E; ++I)
       dispatch(*I);
-    for (llvm::ArrayRef<NamedDecl*>::iterator
-           I = D->getDeclsInPrototypeScope().begin(), E = D->getDeclsInPrototypeScope().end();
-         I != E; ++I)
-      dispatch(*I);
     if (D->doesThisDeclarationHaveABody())
       dispatch(D->getBody());
   }
diff --git a/lib/Parse/ParseDecl.cpp b/lib/Parse/ParseDecl.cpp
index 835a652910..4d93eaf85d 100644
--- a/lib/Parse/ParseDecl.cpp
+++ b/lib/Parse/ParseDecl.cpp
@@ -4226,8 +4226,6 @@ void Parser::ParseFunctionDeclarator(Declarator &D,
   ExprResult NoexceptExpr;
   ParsedType TrailingReturnType;
   
-  Actions.ActOnStartFunctionDeclarator();
-
   SourceLocation EndLoc;
   if (isFunctionDeclaratorIdentifierList()) {
     if (RequiresArg)
diff --git a/lib/Sema/IdentifierResolver.cpp b/lib/Sema/IdentifierResolver.cpp
index 218323134a..b4691617d0 100644
--- a/lib/Sema/IdentifierResolver.cpp
+++ b/lib/Sema/IdentifierResolver.cpp
@@ -113,7 +113,7 @@ bool IdentifierResolver::isDeclInScope(Decl *D, DeclContext *Ctx,
                              bool ExplicitInstantiationOrSpecialization) const {
   Ctx = Ctx->getRedeclContext();
 
-  if (Ctx->isFunctionOrMethod() || S->isFunctionPrototypeScope()) {
+  if (Ctx->isFunctionOrMethod()) {
     // Ignore the scopes associated within transparent declaration contexts.
     while (S->getEntity() &&
            ((DeclContext *)S->getEntity())->isTransparentContext())
diff --git a/lib/Sema/Scope.cpp b/lib/Sema/Scope.cpp
index 10f12ce844..c76f61af6c 100644
--- a/lib/Sema/Scope.cpp
+++ b/lib/Sema/Scope.cpp
@@ -59,13 +59,3 @@ void Scope::Init(Scope *parent, unsigned flags) {
   Entity = 0;
   ErrorTrap.reset();
 }
-
-bool Scope::containedInPrototypeScope() const {
-  const Scope *S = this;
-  while (S) {
-    if (S->isFunctionPrototypeScope())
-      return true;
-    S = S->getParent();
-  }
-  return false;
-}
diff --git a/lib/Sema/Sema.cpp b/lib/Sema/Sema.cpp
index c5841c0edd..cfb4e4c91b 100644
--- a/lib/Sema/Sema.cpp
+++ b/lib/Sema/Sema.cpp
@@ -94,7 +94,7 @@ Sema::Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
     ObjCShouldCallSuperDealloc(false),
     ObjCShouldCallSuperFinalize(false),
     TUKind(TUKind),
-    NumSFINAEErrors(0), InFunctionDeclarator(false), SuppressAccessChecking(false), 
+    NumSFINAEErrors(0), SuppressAccessChecking(false), 
     AccessCheckingSFINAE(false), InNonInstantiationSFINAEContext(false),
     NonInstantiationEntries(0), ArgumentPackSubstitutionIndex(-1),
     CurrentInstantiationScope(0), TyposCorrected(0),
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 41477a49c8..f091d858b5 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -1249,10 +1249,6 @@ void Sema::ActOnPopScope(SourceLocation Loc, Scope *S) {
   }
 }
 
-void Sema::ActOnStartFunctionDeclarator() {
-  InFunctionDeclarator = true;
-}
-
 /// \brief Look for an Objective-C class in the translation unit.
 ///
 /// \param Id The name of the Objective-C class we're looking for. If
@@ -4814,8 +4810,6 @@ Sema::ActOnFunctionDeclarator(Scope *S, Declarator &D, DeclContext *DC,
 
   assert(R.getTypePtr()->isFunctionType());
 
-  InFunctionDeclarator = false;
-
   // TODO: consider using NameInfo for diagnostic.
   DeclarationNameInfo NameInfo = GetNameForDeclarator(D);
   DeclarationName Name = NameInfo.getName();
@@ -5247,15 +5241,6 @@ Sema::ActOnFunctionDeclarator(Scope *S, Declarator &D, DeclContext *DC,
   // Finally, we know we have the right number of parameters, install them.
   NewFD->setParams(Params);
 
-  // Find all anonymous symbols defined during the declaration of this function
-  // and add to NewFD. This lets us track decls such 'enum Y' in:
-  //
-  //   void f(enum Y {AA} x) {}
-  //
-  // which would otherwise incorrectly end up in the translation unit scope.
-  NewFD->setDeclsInPrototypeScope(DeclsInPrototypeScope);
-  DeclsInPrototypeScope.clear();
-
   // Process the non-inheritable attributes on this declaration.
   ProcessDeclAttributes(S, NewFD, D,
                         /*NonInheritable=*/true, /*Inheritable=*/false);
@@ -7240,43 +7225,6 @@ Decl *Sema::ActOnStartOfFunctionDef(Scope *FnBodyScope, Decl *D) {
     }
   }
 
-  // If we had any tags defined in the function prototype,
-  // introduce them into the function scope.
-  if (FnBodyScope) {
-    for (llvm::ArrayRef<NamedDecl*>::iterator I = FD->getDeclsInPrototypeScope().begin(),
-           E = FD->getDeclsInPrototypeScope().end(); I != E; ++I) {
-      NamedDecl *D = *I;
-
-      // Some of these decls (like enums) may have been pinned to the translation unit
-      // for lack of a real context earlier. If so, remove from the translation unit
-      // and reattach to the current context.
-      if (D->getLexicalDeclContext() == Context.getTranslationUnitDecl()) {
-        // Is the decl actually in the context?
-        for (DeclContext::decl_iterator DI = Context.getTranslationUnitDecl()->decls_begin(),
-               DE = Context.getTranslationUnitDecl()->decls_end(); DI != DE; ++DI) {
-          if (*DI == D) {  
-            Context.getTranslationUnitDecl()->removeDecl(D);
-            break;
-          }
-        }
-        // Either way, reassign the lexical decl context to our FunctionDecl.
-        D->setLexicalDeclContext(CurContext);
-      }
-
-      // If the decl has a non-null name, make accessible in the current scope.
-      if (!D->getName().empty())
-        PushOnScopeChains(D, FnBodyScope, /*AddToContext=*/false);
-
-      // Similarly, dive into enums and fish their constants out, making them
-      // accessible in this scope.
-      if (EnumDecl *ED = dyn_cast<EnumDecl>(D)) {
-        for (EnumDecl::enumerator_iterator EI = ED->enumerator_begin(),
-               EE = ED->enumerator_end(); EI != EE; ++EI)
-          PushOnScopeChains(*EI, FnBodyScope, /*AddToContext=*/false);
-      }
-    }
-  }
-
   // Checking attributes of current function definition
   // dllimport attribute.
   DLLImportAttr *DA = FD->getAttr<DLLImportAttr>();
@@ -8229,12 +8177,7 @@ Decl *Sema::ActOnTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
                   !isa<CXXRecordDecl>(Def) ||
                   cast<CXXRecordDecl>(Def)->getTemplateSpecializationKind() 
                                                == TSK_ExplicitSpecialization) {
-                // A redeclaration in function prototype scope in C isn't
-                // visible elsewhere, so merely issue a warning.
-                if (!getLangOptions().CPlusPlus && S->containedInPrototypeScope())
-                  Diag(NameLoc, diag::warn_redefinition_in_param_list) << Name;
-                else
-                  Diag(NameLoc, diag::err_redefinition) << Name;
+                Diag(NameLoc, diag::err_redefinition) << Name;
                 Diag(Def->getLocation(), diag::note_previous_definition);
                 // If this is a redefinition, recover by making this
                 // struct be anonymous, which will make any later
@@ -8516,12 +8459,6 @@ CreateNewDecl:
         II->isStr("FILE"))
       Context.setFILEDecl(New);
 
-  // If we were in function prototype scope (and not in C++ mode), add this
-  // tag to the list of decls to inject into the function definition scope.
-  if (S->isFunctionPrototypeScope() && !getLangOptions().CPlusPlus &&
-      InFunctionDeclarator && Name)
-    DeclsInPrototypeScope.push_back(New);
-
   OwnedDecl = true;
   return New;
 }
@@ -10205,12 +10142,6 @@ void Sema::ActOnEnumBody(SourceLocation EnumLoc, SourceLocation LBraceLoc,
 
   Enum->completeDefinition(BestType, BestPromotionType,
                            NumPositiveBits, NumNegativeBits);
-
-  // If we're declaring a function, ensure this decl isn't forgotten about -
-  // it needs to go into the function scope.
-  if (InFunctionDeclarator)
-    DeclsInPrototypeScope.push_back(Enum);
-
 }
 
 Decl *Sema::ActOnFileScopeAsmDecl(Expr *expr,