BUG: fix for bug 4423 set language fixes

Source/CMakeLists.txt

@@ -697,6 +697,16 @@ IF(BUILD_TESTING)
       -DCMAKE_TEST_SYSTEM_LIBRARIES:BOOL=${CMAKE_TEST_SYSTEM_LIBRARIES}
       --test-command complex)
 
+    ADD_TEST(SetLang ${CMAKE_CTEST_COMMAND}
+      --build-and-test
+      "${CMake_SOURCE_DIR}/Tests/SetLang"
+      "${CMake_BINARY_DIR}/Tests/SetLang"
+      --build-two-config
+      --build-generator ${CMAKE_TEST_GENERATOR}
+      --build-makeprogram ${CMAKE_TEST_MAKEPROGRAM}
+      --build-project SetLang
+      --test-command bar)
+
 #     ADD_TEST(ConvLibrary ${CMAKE_CTEST_COMMAND}
 #       --build-and-test
 #       "${CMake_SOURCE_DIR}/Tests/ConvLibrary"
@@ -707,6 +717,7 @@ IF(BUILD_TESTING)
 #       --build-project ConvLibrary
 #       --test-command bartest)
 
+
 #    ADD_TEST(complexRelativePaths  ${CMAKE_CTEST_COMMAND}
 #      --build-and-test
 #      "${CMake_SOURCE_DIR}/Tests/ComplexRelativePaths"

Source/cmLocalVisualStudio6Generator.cxx

@@ -421,12 +421,16 @@ void cmLocalVisualStudio6Generator
       compileFlags += cflags;
       }
 
-    const char* lang = this->GlobalGenerator->
-      GetLanguageFromExtension((*sf)->GetSourceExtension().c_str());
+    const char* lang = this->GetSourceFileLanguage(*(*sf));
     if(lang && strcmp(lang, "CXX") == 0)
       {
       // force a C++ file type
       compileFlags += " /TP ";
+      } 
+    else if(strcmp(lang, "C") == 0)
+      {
+      // force to c file type
+      compileFlags += " /TC ";
       }
       
     // Check for extra object-file dependencies.

Source/cmLocalVisualStudio7Generator.cxx

@@ -1148,9 +1148,16 @@ void cmLocalVisualStudio7Generator
       }
     const char* lang = this->GlobalGenerator->GetLanguageFromExtension
       ((*sf)->GetSourceExtension().c_str());
+    const char* sourceLang = this->GetSourceFileLanguage(*(*sf));
     const char* linkLanguage = target.GetLinkerLanguage
       (this->GetGlobalGenerator());
-
+    bool needForceLang = false;
+    // source file does not match its extension language
+    if(lang && sourceLang && strcmp(lang, sourceLang) != 0)
+      {
+      needForceLang = true;
+      lang = sourceLang;
+      }
     // If lang is set, the compiler will generate code automatically.
     // If HEADER_FILE_ONLY is set, we must suppress this generation in
     // the project file
@@ -1159,7 +1166,7 @@ void cmLocalVisualStudio7Generator
 
     // if the source file does not match the linker language
     // then force c or c++
-    if(linkLanguage && lang && strcmp(lang, linkLanguage) != 0)
+    if(needForceLang || (linkLanguage && lang && strcmp(lang, linkLanguage) != 0))
       {
       if(strcmp(lang, "CXX") == 0)
         {

Tests/SetLang/CMakeLists.txt

@@ -0,0 +1,7 @@
+# test forcing a source file language to c++ from c
+project(SetLang)
+add_library(foo foo.c)
+add_executable(bar bar.c)
+set_source_files_properties(foo.c bar.c PROPERTIES LANGUAGE CXX)
+target_link_libraries(bar foo)
+set_target_properties(bar PROPERTIES LINKER_LANGUAGE CXX)

Tests/SetLang/bar.c

@@ -0,0 +1,21 @@
+#include <stdio.h>
+
+int foo();
+class A
+{
+public:
+  A() {this->i = foo();}
+  int i;
+};
+
+int main()
+{
+  A a;
+  if(a.i == 21)
+    {
+    printf("passed foo is 21\n");
+    return 0;
+    }
+  printf("Failed foo is not 21\n");
+  return -1;
+}

Tests/SetLang/foo.c

@@ -0,0 +1,7 @@
+int foo()
+{
+  int r = 10;
+  r++;
+  int ret = r+10;
+  return ret;
+}