Add hook to add attributes to function declarations that we know

about, whether they are builtins or not. Use this to add the
appropriate "format" attribute to NSLog, NSLogv, asprintf, and
vasprintf, and to translate builtin attributes (from Builtins.def)
into actual attributes on the function declaration.

Use the "printf" format attribute on function declarations to
determine whether we should do format string checking, rather than
looking at an ad hoc list of builtins and "known" function names.

Be a bit more careful about when we consider a function a "builtin" in
C++.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@64561 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 27 insertions, 9 deletions

diff --git a/lib/AST/Decl.cpp b/lib/AST/Decl.cpp
index 13b40e8afe..ca1fa0c1e1 100644
--- a/lib/AST/Decl.cpp
+++ b/lib/AST/Decl.cpp
@@ -259,15 +259,33 @@ Stmt *FunctionDecl::getBody(const FunctionDecl *&Definition) const {
 /// will be 0 for functions that do not correspond to a builtin, a
 /// value of type \c Builtin::ID if in the target-independent range 
 /// \c [1,Builtin::First), or a target-specific builtin value.
-unsigned FunctionDecl::getBuiltinID() const {
-  if (getIdentifier() && 
-      (getDeclContext()->isTranslationUnit() ||
-       (isa<LinkageSpecDecl>(getDeclContext()) &&
-        cast<LinkageSpecDecl>(getDeclContext())->getLanguage() 
-          == LinkageSpecDecl::lang_c)))
-    return getIdentifier()->getBuiltinID();
-    
-  // Not a builtin.
+unsigned FunctionDecl::getBuiltinID(ASTContext &Context) const {
+  if (!getIdentifier() || !getIdentifier()->getBuiltinID())
+    return 0;
+
+  unsigned BuiltinID = getIdentifier()->getBuiltinID();
+  if (!Context.BuiltinInfo.isPredefinedLibFunction(BuiltinID))
+    return BuiltinID;
+
+  // This function has the name of a known C library
+  // function. Determine whether it actually refers to the C library
+  // function or whether it just has the same name.
+
+  // 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 &&
+      getDeclContext()->isTranslationUnit())
+    return BuiltinID;
+
+  // If the function is in an extern "C" linkage specification and is
+  // not marked "overloadable", it's the real function.
+  if (isa<LinkageSpecDecl>(getDeclContext()) &&
+      cast<LinkageSpecDecl>(getDeclContext())->getLanguage() 
+        == LinkageSpecDecl::lang_c &&
+      !getAttr<OverloadableAttr>())
+    return BuiltinID;
+
+  // Not a builtin
   return 0;
 }