Make version generation robust to other user-defined tags.

src/version.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/version.h"
 
 // These macros define the version number for the current version.
 // NOTE these macros are used by some of the tool scripts and the build
 // system so their names cannot be changed without changing the scripts.
 #define MAJOR_VERSION     4
 #define MINOR_VERSION     2
 #define BUILD_NUMBER      0
 #define PATCH_LEVEL       0
 // Use 1 for candidates and 0 otherwise.
 // (Boolean macro values are not supported by all preprocessors.)
 #define IS_CANDIDATE_VERSION 1
 
+// Used to mark a version built from a bad tag.
+#define IS_INVALID_VERSION 0
+
 // Define SONAME to have the build system put a specific SONAME into the
 // shared library instead the generic SONAME generated from the V8 version
 // number. This define is mainly used by the build system script.
 #define SONAME            ""
 
+#if IS_INVALID_VERSION
+#define SUFFIX_STRING " (invalid)"
+#else
 #if IS_CANDIDATE_VERSION
-#define CANDIDATE_STRING " (candidate)"
+#define SUFFIX_STRING " (candidate)"
 #else
-#define CANDIDATE_STRING ""
+#define SUFFIX_STRING ""
+#endif
 #endif
 
 #define SX(x) #x
 #define S(x) SX(x)
 
 #if PATCH_LEVEL > 0
 #define VERSION_STRING                                                         \
-    S(MAJOR_VERSION) "." S(MINOR_VERSION) "." S(BUILD_NUMBER) "."              \
-        S(PATCH_LEVEL) CANDIDATE_STRING
+  S(MAJOR_VERSION) "." S(MINOR_VERSION) "." S(BUILD_NUMBER) "." S(PATCH_LEVEL) \
+      SUFFIX_STRING
 #else
-#define VERSION_STRING                                                         \
-    S(MAJOR_VERSION) "." S(MINOR_VERSION) "." S(BUILD_NUMBER)                  \
-        CANDIDATE_STRING
+#define VERSION_STRING \
+  S(MAJOR_VERSION) "." S(MINOR_VERSION) "." S(BUILD_NUMBER) SUFFIX_STRING
 #endif
 
 namespace v8 {
 namespace internal {
 
 int Version::major_ = MAJOR_VERSION;
 int Version::minor_ = MINOR_VERSION;
 int Version::build_ = BUILD_NUMBER;
 int Version::patch_ = PATCH_LEVEL;
 bool Version::candidate_ = (IS_CANDIDATE_VERSION != 0);
@@ skipping 32 matching lines @@
       SNPrintF(str, "libv8-%d.%d.%d%s.so",
                GetMajor(), GetMinor(), GetBuild(), candidate);
     }
   } else {
     // Use specific SONAME.
     SNPrintF(str, "%s", soname_);
   }
 }
 
 } }  // namespace v8::internal