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.

1 files changed, 16 insertions, 2 deletions

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)