Static variables and functions won't collide with standard library

functions, so if we're declaring a static we should implicitly declare
a library function by the same name (e.g., malloc, strdup). Fixes PR3592.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@64736 91177308-0d34-0410-b5e6-96231b3b80d8

lib/AST/Decl.cpp

@@ -271,6 +271,10 @@ unsigned FunctionDecl::getBuiltinID(ASTContext &Context) const {
   // function. Determine whether it actually refers to the C library
   // function or whether it just has the same name.
 
+  // If this is a static function, it's not a builtin.
+  if (getStorageClass() == Static)
+    return 0;
+
   // If this function is at translation-unit scope and we're not in
   // C++, it refers to the C library function.
   if (!Context.getLangOptions().CPlusPlus &&

lib/Sema/SemaDecl.cpp

@@ -1304,7 +1304,9 @@ Sema::ActOnDeclarator(Scope *S, Declarator &D, DeclTy *lastDecl,
   // See if this is a redefinition of a variable in the same scope.
   if (!D.getCXXScopeSpec().isSet() && !D.getCXXScopeSpec().isInvalid()) {
     DC = CurContext;
-    PrevDecl = LookupName(S, Name, LookupOrdinaryName, true, true,
+    PrevDecl = LookupName(S, Name, LookupOrdinaryName, true, 
+                          D.getDeclSpec().getStorageClassSpec() != 
+                            DeclSpec::SCS_static,
                           D.getIdentifierLoc());
   } else { // Something like "int foo::x;"
     DC = static_cast<DeclContext*>(D.getCXXScopeSpec().getScopeRep());

test/Sema/implicit-builtin-decl.c

@@ -41,4 +41,3 @@ void * realloc(void *p, int size) { // expected-warning{{incompatible redeclarat
   // expected-note{{use -ffreestanding to compile as a freestanding implementation}}
   return p;
 }
-

test/Sema/implicit-builtin-redecl.c

@@ -0,0 +1,7 @@
+// RUN: clang -fsyntax-only -verify %s
+
+// PR3592
+static void* malloc(int);
+static void* malloc(int size) {
+  return ((void*)0); /*do not use heap in this file*/
+}