[cfe-dev] Clang for windows

Smith, Kevin B kevin.b.smith at intel.com
Thu Aug 21 14:38:26 PDT 2014

I was playing around with CLANG for windows (clang-cl.exe) and noticed that this doesn't support
_int64, but that it does support __int64.  For Microsoft compiler both __int64 and _int64 are recognized
as a keyword and basic type.  This simple program demonstrates that

$ cat xxy.cpp
typedef unsigned __int64 bb1;

typedef unsigned _int64 bb2;

when preprocessed with the VS 2012 C++ compiler, using cl -E xxy.cpp, this yields:
$ cl -E xxy.cpp
Microsoft (R) C/C++ Optimizing Compiler Version 17.00.50727.1 for x86
Copyright (C) Microsoft Corporation.  All rights reserved.

#line 1 "xxy.cpp"
typedef unsigned __int64 bb1;

typedef unsigned _int64 bb2;

showing that the Microsoft compiler hasn't simply created a #define _int64 __int64 instead of treating _int64 as a keyword.
So, I expect clang-cl should do the same thing.  The following simple patch for CLANG is probably the correct way
to remedy this, and it seemed to work for me.  FWIW, I found this in the SPEC 2000 INT program 186.crafty, which uses the
_int64 type directly.

$ svn diff
Index: include/clang/Basic/TokenKinds.def
--- include/clang/Basic/TokenKinds.def  (revision 216129)
+++ include/clang/Basic/TokenKinds.def  (working copy)
@@ -558,6 +558,7 @@
 ALIAS("_uuidof"          , __uuidof   , KEYMS | KEYBORLAND)
 ALIAS("_inline"          , inline     , KEYMS)
 ALIAS("_declspec"        , __declspec , KEYMS)
+ALIAS("_int64"           , __int64    , KEYMS)

 // Borland Extensions which should be disabled in strict conformance mode.
 ALIAS("_pascal"      , __pascal   , KEYBORLAND)

Kevin B. Smith

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