[cfe-dev] [PATCH] __format__ attribute with function pointers

[Nuno Lopes]

Hi,

Here's a patch to fix the handling of the __format__ attribute with function
pointers.
Regards,
Nuno 
Index: test/Sema/format-attribute.c
===================================================================
--- test/Sema/format-attribute.c        (revision 48361)
+++ test/Sema/format-attribute.c        (working copy)
@@ -14,3 +14,5 @@

void y(char *str) __attribute__((format(strftime, 1,0))); // no-error
void z(char *str, int c, ...) __attribute__((format(strftime, 1,2))); // 
expected-error {{strftime format attribute requires 3rd parameter to be 0}}
+
+int (*f_ptr)(char*,...) __attribute__((format(printf, 1,2))); // no-error
Index: Sema/SemaDecl.cpp
===================================================================
--- Sema/SemaDecl.cpp   (revision 48361)
+++ Sema/SemaDecl.cpp   (working copy)
@@ -2117,6 +2117,24 @@
  d->addAttr(new NoThrowAttr());
}

+static const FunctionTypeProto *getFunctionProto(Decl *d) {
+  ValueDecl *decl = dyn_cast<ValueDecl>(d);
+  if (!decl) return 0;
+
+  QualType Ty = decl->getType();
+
+  if (Ty->isFunctionPointerType()) {
+    const PointerType *PtrTy = Ty->getAsPointerType();
+    Ty = PtrTy->getPointeeType();
+  }
+
+  if (const FunctionType *FnTy = Ty->getAsFunctionType())
+    return dyn_cast<FunctionTypeProto>(FnTy->getAsFunctionType());
+
+  return 0;
+}
+
+
/// Handle __attribute__((format(type,idx,firstarg))) attributes
/// based on http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html
void Sema::HandleFormatAttribute(Decl *d, AttributeList *rawAttr) {
@@ -2133,22 +2151,18 @@
    return;
  }

-  FunctionDecl *Fn = dyn_cast<FunctionDecl>(d);
-  if (!Fn) {
+  const FunctionTypeProto *proto = getFunctionProto(d);
+
+  if (!proto) {
    Diag(rawAttr->getLoc(), diag::warn_attribute_wrong_decl_type,
           "format", "function");
    return;
  }

-  const FunctionTypeProto *proto =
-      dyn_cast<FunctionTypeProto>(Fn->getType()->getAsFunctionType());
-  if (!proto)
-    return;
-
  // FIXME: in C++ the implicit 'this' function parameter also counts.
  // this is needed in order to be compatible with GCC
  // the index must start in 1 and the limit is numargs+1
-  unsigned NumArgs  = Fn->getNumParams();
+  unsigned NumArgs  = proto->getNumArgs();
  unsigned FirstIdx = 1;

  const char *Format = rawAttr->getParameterName()->getName();
_______________________________________________
cfe-dev mailing list
cfe-dev@cs.uiuc.edu
http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev