Add generator expressions for compiler versions.

New generator expressions allow retrieval of the version per language,
as well as equality comparison.

Source/cmDocumentGeneratorExpressions.h

@@ -54,6 +54,13 @@
   "else '0'.\n"                                                         \
   "  $<VERSION_EQUAL:v1,v2>    = '1' if v1 is the same version as v2, " \
   "else '0'.\n"                                                         \
+  "  $<C_COMPILER_VERSION>     = The version of the C compiler used.\n" \
+  "  $<C_COMPILER_VERSION:ver> = '1' if the version of the C "          \
+  "compiler matches ver, otherwise '0'.\n"                              \
+  "  $<CXX_COMPILER_VERSION>   = The version of the CXX compiler "      \
+  "used.\n"                                                             \
+  "  $<CXX_COMPILER_VERSION:ver> = '1' if the version of the CXX "      \
+  "compiler matches ver, otherwise '0'.\n"                              \
   "  $<TARGET_FILE:tgt>        = main file (.exe, .so.1.2, .a)\n"       \
   "  $<TARGET_LINKER_FILE:tgt> = file used to link (.a, .lib, .so)\n"   \
   "  $<TARGET_SONAME_FILE:tgt> = file with soname (.so.3)\n"            \

Source/cmGeneratorExpressionEvaluator.cxx

@@ -341,6 +341,102 @@ static const struct CXXCompilerIdNode : public CompilerIdNode
   }
 } cxxCompilerIdNode;
 
+//----------------------------------------------------------------------------
+struct CompilerVersionNode : public cmGeneratorExpressionNode
+{
+  CompilerVersionNode() {}
+
+  virtual int NumExpectedParameters() const { return ZeroOrMoreParameters; }
+
+  std::string EvaluateWithLanguage(const std::vector<std::string> &parameters,
+                       cmGeneratorExpressionContext *context,
+                       const GeneratorExpressionContent *content,
+                       cmGeneratorExpressionDAGChecker *,
+                       const std::string &lang) const
+  {
+    const char *compilerVersion = context->Makefile ?
+                              context->Makefile->GetSafeDefinition((
+                        "CMAKE_" + lang + "_COMPILER_VERSION").c_str()) : "";
+    if (parameters.size() == 0)
+      {
+      return compilerVersion ? compilerVersion : "";
+      }
+
+    cmsys::RegularExpression compilerIdValidator;
+    compilerIdValidator.compile("^[0-9\\.]*$");
+    if (!compilerIdValidator.find(parameters.begin()->c_str()))
+      {
+      reportError(context, content->GetOriginalExpression(),
+                  "Expression syntax not recognized.");
+      return std::string();
+      }
+    if (!compilerVersion)
+      {
+      return parameters.front().empty() ? "1" : "0";
+      }
+
+    return cmSystemTools::VersionCompare(cmSystemTools::OP_EQUAL,
+                                      parameters.begin()->c_str(),
+                                      compilerVersion) ? "1" : "0";
+  }
+};
+
+//----------------------------------------------------------------------------
+static const struct CCompilerVersionNode : public CompilerVersionNode
+{
+  CCompilerVersionNode() {}
+
+  std::string Evaluate(const std::vector<std::string> &parameters,
+                       cmGeneratorExpressionContext *context,
+                       const GeneratorExpressionContent *content,
+                       cmGeneratorExpressionDAGChecker *dagChecker) const
+  {
+    if (parameters.size() != 0 && parameters.size() != 1)
+      {
+      reportError(context, content->GetOriginalExpression(),
+          "$<C_COMPILER_VERSION> expression requires one or two parameters");
+      return std::string();
+      }
+    if (!context->HeadTarget)
+      {
+      reportError(context, content->GetOriginalExpression(),
+          "$<C_COMPILER_VERSION> may only be used with targets.  It may not "
+          "be used with add_custom_command.");
+      }
+    return this->EvaluateWithLanguage(parameters, context, content,
+                                      dagChecker, "C");
+  }
+} cCompilerVersionNode;
+
+//----------------------------------------------------------------------------
+static const struct CxxCompilerVersionNode : public CompilerVersionNode
+{
+  CxxCompilerVersionNode() {}
+
+  std::string Evaluate(const std::vector<std::string> &parameters,
+                       cmGeneratorExpressionContext *context,
+                       const GeneratorExpressionContent *content,
+                       cmGeneratorExpressionDAGChecker *dagChecker) const
+  {
+    if (parameters.size() != 0 && parameters.size() != 1)
+      {
+      reportError(context, content->GetOriginalExpression(),
+          "$<CXX_COMPILER_VERSION> expression requires one or two "
+          "parameters");
+      return std::string();
+      }
+    if (!context->HeadTarget)
+      {
+      reportError(context, content->GetOriginalExpression(),
+          "$<CXX_COMPILER_VERSION> may only be used with targets.  It may "
+          "not be used with add_custom_command.");
+      }
+    return this->EvaluateWithLanguage(parameters, context, content,
+                                      dagChecker, "CXX");
+  }
+} cxxCompilerVersionNode;
+
+
 //----------------------------------------------------------------------------
 static const struct VersionGreaterNode : public cmGeneratorExpressionNode
 {
@@ -1247,6 +1343,10 @@ cmGeneratorExpressionNode* GetNode(const std::string &identifier)
     return &versionLessNode;
   else if (identifier == "VERSION_EQUAL")
     return &versionEqualNode;
+  else if (identifier == "C_COMPILER_VERSION")
+    return &cCompilerVersionNode;
+  else if (identifier == "CXX_COMPILER_VERSION")
+    return &cxxCompilerVersionNode;
   else if (identifier == "CONFIGURATION")
     return &configurationNode;
   else if (identifier == "CONFIG")

Tests/CompileOptions/CMakeLists.txt

@@ -5,11 +5,23 @@ project(CompileOptions)
 add_library(testlib other.cpp)
 
 add_executable(CompileOptions main.cpp)
+
+macro(get_compiler_test_genex lst lang)
+  list(APPEND ${lst} -DTEST_${lang}_COMPILER_VERSION="$<${lang}_COMPILER_VERSION>")
+  list(APPEND ${lst} -DTEST_${lang}_COMPILER_VERSION_EQUALITY=$<${lang}_COMPILER_VERSION:${CMAKE_${lang}_COMPILER_VERSION}>)
+endmacro()
+
+get_compiler_test_genex(c_tests C)
+get_compiler_test_genex(cxx_tests CXX)
+
 set_property(TARGET CompileOptions PROPERTY COMPILE_OPTIONS
   "-DTEST_DEFINE"
   "-DNEEDS_ESCAPE=\"E$CAPE\""
   "$<$<CXX_COMPILER_ID:GNU>:-DTEST_DEFINE_GNU>"
+  ${c_tests}
+  ${cxx_tests}
   )
+
 target_link_libraries(CompileOptions testlib)
 
 if(CMAKE_CXX_COMPILER_ID MATCHES "GNU")
@@ -18,3 +30,9 @@ if(CMAKE_CXX_COMPILER_ID MATCHES "GNU")
       "DO_GNU_TESTS"
   )
 endif()
+
+target_compile_definitions(CompileOptions
+  PRIVATE
+    "EXPECTED_C_COMPILER_VERSION=\"${CMAKE_C_COMPILER_VERSION}\""
+    "EXPECTED_CXX_COMPILER_VERSION=\"${CMAKE_CXX_COMPILER_VERSION}\""
+)

Tests/CompileOptions/main.cpp

@@ -16,5 +16,9 @@
 
 int main()
 {
-  return strcmp(NEEDS_ESCAPE, "E$CAPE") == 0 ? 0 : 1;
+  return (strcmp(NEEDS_ESCAPE, "E$CAPE") == 0
+      && strcmp(EXPECTED_C_COMPILER_VERSION, TEST_C_COMPILER_VERSION) == 0
+      && strcmp(EXPECTED_CXX_COMPILER_VERSION, TEST_CXX_COMPILER_VERSION) == 0
+      && TEST_C_COMPILER_VERSION_EQUALITY == 1
+      && TEST_CXX_COMPILER_VERSION_EQUALITY == 1) ? 0 : 1;
 }