Make __FreeBSD_cc_version predefined macro configurable at build time

The `FreeBSDTargetInfo` class has always set the `__FreeBSD_cc_version`
predefined macro to a rather static value, calculated from the major OS
version.

In the FreeBSD base system, we will start incrementing the value of this
macro whenever we make any signifant change to clang, so we need a way
to configure the macro's value at build time.

Use `FREEBSD_CC_VERSION` for this, which we can define in the FreeBSD
build system using either the `-D` command line option, or an include
file.  Stock builds will keep the earlier value.

Differential Revision: http://reviews.llvm.org/D20037

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@270240 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Basic/Targets.cpp b/lib/Basic/Targets.cpp
index 2a018071000784f5ae688031c855bcabbbe14c77..cd9c51adab9e5dc6c2ae0a13de5f96ca1a63f12a 100644 (file)
--- a/lib/Basic/Targets.cpp
+++ b/lib/Basic/Targets.cpp
@@ -308,6 +308,10 @@ public:
   }
 };
 
+#ifndef FREEBSD_CC_VERSION
+#define FREEBSD_CC_VERSION 0U
+#endif
+
 // FreeBSD Target
 template<typename Target>
 class FreeBSDTargetInfo : public OSTargetInfo<Target> {
@@ -318,10 +322,13 @@ protected:
 
     unsigned Release = Triple.getOSMajorVersion();
     if (Release == 0U)
-      Release = 8;
+      Release = 8U;
+    unsigned CCVersion = FREEBSD_CC_VERSION;
+    if (CCVersion == 0U)
+      CCVersion = Release * 100000U + 1U;
 
     Builder.defineMacro("__FreeBSD__", Twine(Release));
-    Builder.defineMacro("__FreeBSD_cc_version", Twine(Release * 100000U + 1U));
+    Builder.defineMacro("__FreeBSD_cc_version", Twine(CCVersion));
     Builder.defineMacro("__KPRINTF_ATTRIBUTE__");
     DefineStd(Builder, "unix", Opts);
     Builder.defineMacro("__ELF__");