[OpenCL] Eliminate warning when declaring OpenCL builtin functions

[yaxunl]

Summary

OpenCL builtin functions are usually declared in header files. Currently clang emits warning for OpenCL builtin functions which have the same name as standard C library functions, e.g.

builtin.cl:1:37: warning: incompatible redeclaration of library function 'acos'
float __attribute__((overloadable)) acos(float);
                                    ^
builtin.cl:1:37: note: 'acos' is a builtin with type 'double (double)'

This commit eliminates such warnings.

[pxli168]

lib/Sema/SemaLookup.cpp

698

I think the

C99 standard headers

can cover those

...
ctype.h, complex.h, errno.h, fenv.h, float.h, inttypes.h, limits.h,
locale.h, setjmp.h, signal.h, stdarg.h, stdio.h, stdlib.h, string.h,
// tgmath.h, time.h, wchar.h and wctype.h

The comment shuold not be copy and paste as Anastasia will say.

[yaxunl]

revised as Xiuli suggested.

[Anastasia]

lib/Sema/SemaLookup.cpp

698

Absolutely! Just a reference to the section in spec and a short summary sentence should be enough.

However, could we also combine this with CPP comment above (see another comment).

699

I think we could combine this with the CPP check above?

[yaxunl]

revised as Anastasia suggested.

[Anastasia]

LGTM!

[pxli168]

Thanks, LGTM!

[yaxunl]

committed

[pxli168]

I see you have committed this patch, you can try to follow the guide here:
http://llvm.org/docs/Phabricator.html#committing-a-change
To add something in your commit and then the system will automatic close the diff and have link to the commmit.
This will help others to find the review process and easy to track the commit.
Or you can just use the arc tool to make the commit automatically.
Thanks
Xiuli

[yaxunl]

Thanks Xiuli.

It seems the review was not closed automatically due to missing Differential Revision: <URL> at the end of commit message. Next time I will add the url to the review summary.

lib/Sema/SemaLookup.cpp

             S.Context.BuiltinInfo.isPredefinedLibFunction(BuiltinID))
           return false;
 
+        // By OpenCL spec v1.2 s6.9.f, the library functions defined in the
+        // C99 standard headers are not available.
+        if (S.getLangOpts().OpenCL &&
+            S.Context.BuiltinInfo.isPredefinedLibFunction(BuiltinID))
+          return false;
+
         if (NamedDecl *D = S.LazilyCreateBuiltin((IdentifierInfo *)II,
                                                  BuiltinID, S.TUScope,
                                                  R.isForRedeclaration(),

test/SemaOpenCL/builtin.cl

+// RUN: %clang_cc1 %s -verify -pedantic -fsyntax-only
+
+float __attribute__((overloadable)) acos(float); // expected-no-diagnostics