Fortran: Add infrastructure to detect compiler version (#15372)

Fortran does not offer syntax to compose a string literal at
preprocessing time from numeric compuations.  Instead encode each digit
of each component as a separate INFO string and compose them in CMake
code after extraction.  Support MAJOR, MINOR, PATCH, and TWEAK
components with up to 8 digits each.

1 files changed, 40 insertions, 1 deletions

diff --git a/Modules/CMakeDetermineCompilerId.cmake b/Modules/CMakeDetermineCompilerId.cmake
index dfed00e77e..d22a867c53 100644
--- a/Modules/CMakeDetermineCompilerId.cmake
+++ b/Modules/CMakeDetermineCompilerId.cmake
@@ -409,12 +409,28 @@ function(CMAKE_DETERMINE_COMPILER_ID_CHECK lang file)
     # Read the compiler identification string from the executable file.
     set(COMPILER_ID)
     set(COMPILER_VERSION)
+    set(COMPILER_VERSION_MAJOR 0)
+    set(COMPILER_VERSION_MINOR 0)
+    set(COMPILER_VERSION_PATCH 0)
+    set(COMPILER_VERSION_TWEAK 0)
+    set(HAVE_COMPILER_VERSION_MAJOR 0)
+    set(HAVE_COMPILER_VERSION_MINOR 0)
+    set(HAVE_COMPILER_VERSION_PATCH 0)
+    set(HAVE_COMPILER_VERSION_TWEAK 0)
+    set(DIGIT_VALUE_1 1)
+    set(DIGIT_VALUE_2 10)
+    set(DIGIT_VALUE_3 100)
+    set(DIGIT_VALUE_4 1000)
+    set(DIGIT_VALUE_5 10000)
+    set(DIGIT_VALUE_6 100000)
+    set(DIGIT_VALUE_7 1000000)
+    set(DIGIT_VALUE_8 10000000)
     set(PLATFORM_ID)
     set(ARCHITECTURE_ID)
     set(SIMULATE_ID)
     set(SIMULATE_VERSION)
     file(STRINGS ${file}
-      CMAKE_${lang}_COMPILER_ID_STRINGS LIMIT_COUNT 6 REGEX "INFO:[A-Za-z0-9_]+\\[[^]]*\\]")
+      CMAKE_${lang}_COMPILER_ID_STRINGS LIMIT_COUNT 38 REGEX "INFO:[A-Za-z0-9_]+\\[[^]]*\\]")
     set(COMPILER_ID_TWICE)
     foreach(info ${CMAKE_${lang}_COMPILER_ID_STRINGS})
       if("${info}" MATCHES "INFO:compiler\\[([^]\"]*)\\]")
@@ -433,6 +449,15 @@ function(CMAKE_DETERMINE_COMPILER_ID_CHECK lang file)
         string(REGEX REPLACE "^0+([0-9])" "\\1" COMPILER_VERSION "${CMAKE_MATCH_1}")
         string(REGEX REPLACE "\\.0+([0-9])" ".\\1" COMPILER_VERSION "${COMPILER_VERSION}")
       endif()
+      foreach(comp MAJOR MINOR PATCH TWEAK)
+        foreach(digit 1 2 3 4 5 6 7 8 9)
+          if("${info}" MATCHES "INFO:compiler_version_${comp}_digit_${digit}\\[([0-9])\\]")
+            set(value ${CMAKE_MATCH_1})
+            math(EXPR COMPILER_VERSION_${comp} "${COMPILER_VERSION_${comp}} + ${value} * ${DIGIT_VALUE_${digit}}")
+            set(HAVE_COMPILER_VERSION_${comp} 1)
+          endif()
+        endforeach()
+      endforeach()
       if("${info}" MATCHES "INFO:simulate\\[([^]\"]*)\\]")
         set(SIMULATE_ID "${CMAKE_MATCH_1}")
       endif()
@@ -445,6 +470,20 @@ function(CMAKE_DETERMINE_COMPILER_ID_CHECK lang file)
       endif()
     endforeach()
 
+    # Construct compiler version from components if needed.
+    if(NOT DEFINED COMPILER_VERSION AND HAVE_COMPILER_VERSION_MAJOR)
+      set(COMPILER_VERSION "${COMPILER_VERSION_MAJOR}")
+      if(HAVE_COMPILER_VERSION_MINOR)
+        set(COMPILER_VERSION "${COMPILER_VERSION}.${COMPILER_VERSION_MINOR}")
+        if(HAVE_COMPILER_VERSION_PATCH)
+          set(COMPILER_VERSION "${COMPILER_VERSION}.${COMPILER_VERSION_PATCH}")
+          if(HAVE_COMPILER_VERSION_TWEAK)
+            set(COMPILER_VERSION "${COMPILER_VERSION}.${COMPILER_VERSION_TWEAK}")
+          endif()
+        endif()
+      endif()
+    endif()
+
     # Detect the exact architecture from the PE header.
     if(WIN32)
       # The offset to the PE signature is stored at 0x3c.