Place implictly declared functions at block scope

Such implicitly declared functions behave as if the enclosing block
contained the declaration extern int name() (C90, 6.3.3.2 Function calls),
thus their names should have block scope (C90, 6.1.2.1 Scope of identifiers).

This patch fixes https://bugs.llvm.org/show_bug.cgi?id=33224

Differential Revision: https://reviews.llvm.org/D33676

llvm-svn: 310616

1 files changed, 6 insertions, 2 deletions

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 6bcb0231743..d19ace9c43b 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -12677,12 +12677,16 @@ NamedDecl *Sema::ImplicitlyDefineFunction(SourceLocation Loc,
                 SourceLocation());
   D.SetIdentifier(&II, Loc);
 
-  // Insert this function into translation-unit scope.
+  // Insert this function into the enclosing block scope.
+  while (S && !S->isCompoundStmtScope())
+    S = S->getParent();
+  if (S == nullptr)
+    S = TUScope;
 
   DeclContext *PrevDC = CurContext;
   CurContext = Context.getTranslationUnitDecl();
 
-  FunctionDecl *FD = cast<FunctionDecl>(ActOnDeclarator(TUScope, D));
+  FunctionDecl *FD = cast<FunctionDecl>(ActOnDeclarator(S, D));
   FD->setImplicit();
 
   CurContext = PrevDC;