Update __VERSION__ to remove the hardcoded 4.2.1 version

Summary:
Just like in https://reviews.llvm.org/D56803
for -dumpversion

Reviewers: rnk

Reviewed By: rnk

Subscribers: dexonsmith, lebedev.ri, hubert.reinterpretcast, xbolva00, fedor.sergeev, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D63048

llvm-svn: 366091

clang/docs/LanguageExtensions.rst

@@ -324,6 +324,8 @@ option for a warning and returns true if that is a valid warning option.
   ...
   #endif
 
+.. _languageextensions-builtin-macros:
+
 Builtin Macros
 ==============
 

clang/docs/ReleaseNotes.rst

@@ -56,6 +56,12 @@ Improvements to Clang's diagnostics
 Non-comprehensive list of changes in this release
 -------------------------------------------------
 
+- The ``__VERSION__`` macro has been updated.
+  Previously this macro contained the string '4.2.1 Compatible' to achieve
+  compatibility with GCC 4.2.1, but that should no longer be necessary.
+  However, to retrieve Clang's version, please favor the one of the macro
+  defined in :ref:`clang namespaced version macros <languageextensions-builtin-macros>`.
+
 - ...
 
 

clang/lib/Frontend/InitPreprocessor.cpp

@@ -604,10 +604,9 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
   // Support for #pragma redefine_extname (Sun compatibility)
   Builder.defineMacro("__PRAGMA_REDEFINE_EXTNAME", "1");
 
-  // As sad as it is, enough software depends on the __VERSION__ for version
-  // checks that it is necessary to report 4.2.1 (the base GCC version we claim
-  // compatibility with) first.
-  Builder.defineMacro("__VERSION__", "\"4.2.1 Compatible " +
+  // Previously this macro was set to a string aiming to achieve compatibility
+  // with GCC 4.2.1. Now, just return the full Clang version
+  Builder.defineMacro("__VERSION__", "\"" +
                       Twine(getClangFullCPPVersion()) + "\"");
 
   // Initialize language-specific preprocessor defines.

clang/test/Preprocessor/init.c

@@ -8169,7 +8169,7 @@
 // SPARC:#define __UINT_LEAST8_MAX__ 255
 // SPARC:#define __UINT_LEAST8_TYPE__ unsigned char
 // SPARC:#define __USER_LABEL_PREFIX__
-// SPARC:#define __VERSION__ "4.2.1 Compatible{{.*}}
+// SPARC:#define __VERSION__ "Clang{{.*}}
 // SPARC:#define __WCHAR_MAX__ 2147483647
 // SPARC:#define __WCHAR_TYPE__ int
 // SPARC:#define __WCHAR_WIDTH__ 32
@@ -9041,7 +9041,7 @@
 // X86_64-CLOUDABI:#define __UINT_LEAST8_MAX__ 255
 // X86_64-CLOUDABI:#define __UINT_LEAST8_TYPE__ unsigned char
 // X86_64-CLOUDABI:#define __USER_LABEL_PREFIX__
-// X86_64-CLOUDABI:#define __VERSION__ "4.2.1 Compatible{{.*}}
+// X86_64-CLOUDABI:#define __VERSION__ "Clang{{.*}}
 // X86_64-CLOUDABI:#define __WCHAR_MAX__ 2147483647
 // X86_64-CLOUDABI:#define __WCHAR_TYPE__ int
 // X86_64-CLOUDABI:#define __WCHAR_WIDTH__ 32