On 12/20/2016 6:56 PM, Richard Smith wrote:
On 20 December 2016 at 18:14, Richard Smith <rich...@metafoo.co.uk
<mailto:rich...@metafoo.co.uk>> wrote:
On 19 December 2016 at 17:00, Friedman, Eli via cfe-commits
<cfe-commits@lists.llvm.org <mailto:cfe-commits@lists.llvm.org>>
wrote:
On 12/19/2016 3:59 PM, Richard Smith via cfe-commits wrote:
Author: rsmith
Date: Mon Dec 19 17:59:34 2016
New Revision: 290146
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/vfprintf-valid-redecl.c?rev=290146&r1=290145&r2=290146&view=diff
<http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/vfprintf-valid-redecl.c?rev=290146&r1=290145&r2=290146&view=diff>
==============================================================================
--- cfe/trunk/test/Sema/vfprintf-valid-redecl.c (original)
+++ cfe/trunk/test/Sema/vfprintf-valid-redecl.c Mon Dec 19
17:59:34 2016
@@ -1,16 +1,18 @@
// RUN: %clang_cc1 %s -fsyntax-only -pedantic -verify
// RUN: %clang_cc1 %s -fsyntax-only -pedantic -verify
-DPREDECLARE
-// expected-no-diagnostics
#ifdef PREDECLARE
// PR16344
// Clang has defined 'vfprint' in builtin list. If the
following line occurs before any other
// `vfprintf' in this file, and we
getPreviousDecl()->getTypeSourceInfo() on it, then we will
// get a null pointer since the one in builtin list
doesn't has valid TypeSourceInfo.
-int vfprintf(void) { return 0; }
+int vfprintf(void) { return 0; } // expected-warning
{{requires inclusion of the header <stdio.h>}}
#endif
// PR4290
// The following declaration is compatible with
vfprintf, so we shouldn't
-// warn.
+// reject.
int vfprintf();
+#ifndef PREDECLARE
+// expected-warning@-2 {{requires inclusion of the header
<stdio.h>}}
+#endif
We shouldn't warn here; this declaration of vfprintf() is
compatible with the actual prototype. (Granted, you can't
call vfprintf() without including stdio.h, but that's a
separate problem.)
I agree (but I'd note that this is a pre-existing problem for
other lib builtins taking a FILE*, particularly vfscanf). Perhaps
we could deem the builtin to have a FunctionNoProtoType type in C
if it's not variadic and depends on a type that is not yet declared?
What do you think of the attached approach? I'm a little uncomfortable
that we no longer recognise a declaration of sigsetjmp as a builtin if
it has the wrong return type (and issue only a warning for that case).
Alternatively, if we're OK with recognising wrongly-typed declarations
as library builtins in this corner case, we could just remove the
warning entirely.
The "right" approach is probably something a bit more invasive. We could
wait, and attempt to recognize the builtin later, when the function is
declared with a prototype or called. Or we could try to
"forward-declare" FILE (map it to some opaque type until we have an
actual declaration we can use).
Short of that, it's probably okay to leave things as-is for now; better
to have extra warnings in weird edge cases than to miss a warning in a
case where it's important.
-Eli
--
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux
Foundation Collaborative Project
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