Add framework to detect compiler version with its id (#12408)

Teach CMakePlatformId.h to construct an "INFO:compiler_version[]" string
literal from macros COMPILER_VERSION_(MAJOR|MINOR|PATCH|TWEAK) to be
defined in CMake(C|CXX)CompilerId.(c|cpp) for each compiler.  Provide
conversion macros DEC() and HEX() to decode decimal or hex digits from
integer values.  Parse the version out of the compiler id binary along
with the other INFO values already present.

Store the result in variable CMAKE_<LANG>_COMPILER_VERSION in the format
"major[.minor[.patch[.tweak]]]".  Save the value persistently in
CMake(C|CXX)Compiler.cmake in the build tree.  Document the variable for
internal use since we do not set it everywhere yet.

Report the compiler version on the compiler id result line e.g.

  The C compiler identification is GNU 4.5.2

Report CMAKE_(C|CXX)_COMPILER_(ID|VERSION) in SystemInformation test.

6 files changed, 64 insertions, 2 deletions

diff --git a/Modules/CMakeCCompiler.cmake.in b/Modules/CMakeCCompiler.cmake.in
index 04a5cec..b14cf34 100644
--- a/Modules/CMakeCCompiler.cmake.in
+++ b/Modules/CMakeCCompiler.cmake.in
@@ -1,6 +1,7 @@
 SET(CMAKE_C_COMPILER "@CMAKE_C_COMPILER@")
 SET(CMAKE_C_COMPILER_ARG1 "@CMAKE_C_COMPILER_ARG1@")
 SET(CMAKE_C_COMPILER_ID "@CMAKE_C_COMPILER_ID@")
+SET(CMAKE_C_COMPILER_VERSION "@CMAKE_C_COMPILER_VERSION@")
 SET(CMAKE_C_PLATFORM_ID "@CMAKE_C_PLATFORM_ID@")
 @SET_MSVC_C_ARCHITECTURE_ID@
 SET(CMAKE_AR "@CMAKE_AR@")
diff --git a/Modules/CMakeCCompilerId.c.in b/Modules/CMakeCCompilerId.c.in
index c91553a..dd3d2fd 100644
--- a/Modules/CMakeCCompilerId.c.in
+++ b/Modules/CMakeCCompilerId.c.in
@@ -109,6 +109,9 @@ int main(int argc, char* argv[])
   require += info_compiler[argc];
   require += info_platform[argc];
   require += info_arch[argc];
+#ifdef COMPILER_VERSION_MAJOR
+  require += info_version[argc];
+#endif
   (void)argv;
   return require;
 }
diff --git a/Modules/CMakeCXXCompiler.cmake.in b/Modules/CMakeCXXCompiler.cmake.in
index ea06526..bc3bc2e 100644
--- a/Modules/CMakeCXXCompiler.cmake.in
+++ b/Modules/CMakeCXXCompiler.cmake.in
@@ -1,6 +1,7 @@
 SET(CMAKE_CXX_COMPILER "@CMAKE_CXX_COMPILER@")
 SET(CMAKE_CXX_COMPILER_ARG1 "@CMAKE_CXX_COMPILER_ARG1@")
 SET(CMAKE_CXX_COMPILER_ID "@CMAKE_CXX_COMPILER_ID@")
+SET(CMAKE_CXX_COMPILER_VERSION "@CMAKE_CXX_COMPILER_VERSION@")
 SET(CMAKE_CXX_PLATFORM_ID "@CMAKE_CXX_PLATFORM_ID@")
 @SET_MSVC_CXX_ARCHITECTURE_ID@
 SET(CMAKE_AR "@CMAKE_AR@")
diff --git a/Modules/CMakeCXXCompilerId.cpp.in b/Modules/CMakeCXXCompilerId.cpp.in
index 4c8f497..469290e 100644
--- a/Modules/CMakeCXXCompilerId.cpp.in
+++ b/Modules/CMakeCXXCompilerId.cpp.in
@@ -96,6 +96,9 @@ int main(int argc, char* argv[])
   int require = 0;
   require += info_compiler[argc];
   require += info_platform[argc];
+#ifdef COMPILER_VERSION_MAJOR
+  require += info_version[argc];
+#endif
   (void)argv;
   return require;
 }
diff --git a/Modules/CMakeDetermineCompilerId.cmake b/Modules/CMakeDetermineCompilerId.cmake
index b160dee..686cc9b 100644
--- a/Modules/CMakeDetermineCompilerId.cmake
+++ b/Modules/CMakeDetermineCompilerId.cmake
@@ -55,8 +55,13 @@ FUNCTION(CMAKE_DETERMINE_COMPILER_ID lang flagvar src)
 
   # Display the final identification result.
   IF(CMAKE_${lang}_COMPILER_ID)
+    IF(CMAKE_${lang}_COMPILER_VERSION)
+      SET(_version " ${CMAKE_${lang}_COMPILER_VERSION}")
+    ELSE()
+      SET(_version "")
+    ENDIF()
     MESSAGE(STATUS "The ${lang} compiler identification is "
-      "${CMAKE_${lang}_COMPILER_ID}")
+      "${CMAKE_${lang}_COMPILER_ID}${_version}")
   ELSE(CMAKE_${lang}_COMPILER_ID)
     MESSAGE(STATUS "The ${lang} compiler identification is unknown")
   ENDIF(CMAKE_${lang}_COMPILER_ID)
@@ -65,6 +70,7 @@ FUNCTION(CMAKE_DETERMINE_COMPILER_ID lang flagvar src)
   SET(CMAKE_${lang}_PLATFORM_ID "${CMAKE_${lang}_PLATFORM_ID}" PARENT_SCOPE)
   SET(MSVC_${lang}_ARCHITECTURE_ID "${MSVC_${lang}_ARCHITECTURE_ID}"
     PARENT_SCOPE)
+  SET(CMAKE_${lang}_COMPILER_VERSION "${CMAKE_${lang}_COMPILER_VERSION}" PARENT_SCOPE)
 ENDFUNCTION(CMAKE_DETERMINE_COMPILER_ID)
 
 #-----------------------------------------------------------------------------
@@ -177,9 +183,10 @@ FUNCTION(CMAKE_DETERMINE_COMPILER_ID_CHECK lang file)
   IF(NOT CMAKE_${lang}_COMPILER_ID)
     # Read the compiler identification string from the executable file.
     SET(COMPILER_ID)
+    SET(COMPILER_VERSION)
     SET(PLATFORM_ID)
     FILE(STRINGS ${file}
-      CMAKE_${lang}_COMPILER_ID_STRINGS LIMIT_COUNT 3 REGEX "INFO:")
+      CMAKE_${lang}_COMPILER_ID_STRINGS LIMIT_COUNT 4 REGEX "INFO:")
     SET(HAVE_COMPILER_TWICE 0)
     FOREACH(info ${CMAKE_${lang}_COMPILER_ID_STRINGS})
       IF("${info}" MATCHES ".*INFO:compiler\\[([^]\"]*)\\].*")
@@ -197,6 +204,11 @@ FUNCTION(CMAKE_DETERMINE_COMPILER_ID_CHECK lang file)
         STRING(REGEX REPLACE ".*INFO:arch\\[([^]]*)\\].*" "\\1"
           ARCHITECTURE_ID "${info}")
       ENDIF("${info}" MATCHES ".*INFO:arch\\[([^]\"]*)\\].*")
+      IF("${info}" MATCHES ".*INFO:compiler_version\\[([^]\"]*)\\].*")
+        STRING(REGEX REPLACE ".*INFO:compiler_version\\[([^]]*)\\].*" "\\1" COMPILER_VERSION "${info}")
+        STRING(REGEX REPLACE "^0+([0-9])" "\\1" COMPILER_VERSION "${COMPILER_VERSION}")
+        STRING(REGEX REPLACE "\\.0+([0-9])" ".\\1" COMPILER_VERSION "${COMPILER_VERSION}")
+      ENDIF("${info}" MATCHES ".*INFO:compiler_version\\[([^]\"]*)\\].*")
     ENDFOREACH(info)
 
     # Check if a valid compiler and platform were found.
@@ -204,6 +216,7 @@ FUNCTION(CMAKE_DETERMINE_COMPILER_ID_CHECK lang file)
       SET(CMAKE_${lang}_COMPILER_ID "${COMPILER_ID}")
       SET(CMAKE_${lang}_PLATFORM_ID "${PLATFORM_ID}")
       SET(MSVC_${lang}_ARCHITECTURE_ID "${ARCHITECTURE_ID}")
+      SET(CMAKE_${lang}_COMPILER_VERSION "${COMPILER_VERSION}")
     ENDIF(COMPILER_ID AND NOT COMPILER_ID_TWICE)
 
     # Check the compiler identification string.
@@ -251,6 +264,7 @@ FUNCTION(CMAKE_DETERMINE_COMPILER_ID_CHECK lang file)
   SET(CMAKE_${lang}_PLATFORM_ID "${CMAKE_${lang}_PLATFORM_ID}" PARENT_SCOPE)
   SET(MSVC_${lang}_ARCHITECTURE_ID "${MSVC_${lang}_ARCHITECTURE_ID}"
     PARENT_SCOPE)
+  SET(CMAKE_${lang}_COMPILER_VERSION "${CMAKE_${lang}_COMPILER_VERSION}" PARENT_SCOPE)
   SET(CMAKE_EXECUTABLE_FORMAT "${CMAKE_EXECUTABLE_FORMAT}" PARENT_SCOPE)
 ENDFUNCTION(CMAKE_DETERMINE_COMPILER_ID_CHECK lang)
 
diff --git a/Modules/CMakePlatformId.h.in b/Modules/CMakePlatformId.h.in
index cb3f40a..b69bf63 100644
--- a/Modules/CMakePlatformId.h.in
+++ b/Modules/CMakePlatformId.h.in
@@ -105,6 +105,46 @@
 #  define ARCHITECTURE_ID ""
 #endif
 
+/* Convert integer to decimal digit literals.  */
+#define DEC(n)                   \
+  ('0' + (((n) / 10000000)%10)), \
+  ('0' + (((n) / 1000000)%10)),  \
+  ('0' + (((n) / 100000)%10)),   \
+  ('0' + (((n) / 10000)%10)),    \
+  ('0' + (((n) / 1000)%10)),     \
+  ('0' + (((n) / 100)%10)),      \
+  ('0' + (((n) / 10)%10)),       \
+  ('0' +  ((n) % 10))
+
+/* Convert integer to hex digit literals.  */
+#define HEX(n)             \
+  ('0' + ((n)>>28 & 0xF)), \
+  ('0' + ((n)>>24 & 0xF)), \
+  ('0' + ((n)>>20 & 0xF)), \
+  ('0' + ((n)>>16 & 0xF)), \
+  ('0' + ((n)>>12 & 0xF)), \
+  ('0' + ((n)>>8  & 0xF)), \
+  ('0' + ((n)>>4  & 0xF)), \
+  ('0' + ((n)     & 0xF))
+
+/* Construct a string literal encoding the version number components. */
+#ifdef COMPILER_VERSION_MAJOR
+char const info_version[] = {
+  'I', 'N', 'F', 'O', ':',
+  'c','o','m','p','i','l','e','r','_','v','e','r','s','i','o','n','[',
+  COMPILER_VERSION_MAJOR,
+# ifdef COMPILER_VERSION_MINOR
+  '.', COMPILER_VERSION_MINOR,
+#  ifdef COMPILER_VERSION_PATCH
+   '.', COMPILER_VERSION_PATCH,
+#   ifdef COMPILER_VERSION_TWEAK
+    '.', COMPILER_VERSION_TWEAK,
+#   endif
+#  endif
+# endif
+  ']','\0'};
+#endif
+
 /* Construct the string literal in pieces to prevent the source from
    getting matched.  Store it in a pointer rather than an array
    because some compilers will just produce instructions to fill the