Add new cmdline option -mixin=<filename>

dmd/mars.d

@@ -1541,6 +1541,8 @@ private void setTargetCPU(ref Param params)
         params.cpu = CPU.x87;   // cannot support other instruction sets
 }
 
+} // !IN_LLVM
+
 /**************************************
  * we want to write the mixin expansion file also on error, but there
  * are too many ways to terminate dmd (e.g. fatal() which calls exit(EXIT_FAILURE)),
@@ -1559,6 +1561,9 @@ extern(C) void flushMixins()
     f.write();
 }
 
+version (IN_LLVM) {} else
+{
+
 /****************************************************
  * Parse command line arguments.
  *

driver/cl_options.cpp

@@ -220,6 +220,10 @@ cl::opt<bool>
     hdrKeepAllBodies("Hkeep-all-bodies", cl::ZeroOrMore,
                      cl::desc("Keep all function bodies in .di files"));
 
+cl::opt<std::string> mixinFile("mixin", cl::ZeroOrMore,
+                               cl::desc("Expand and save mixins to <filename>"),
+                               cl::value_desc("filename"));
+
 static cl::opt<bool, true> unittest("unittest", cl::ZeroOrMore,
                                     cl::desc("Compile in unit tests"),
                                     cl::location(global.params.useUnitTests));

driver/cl_options.h

@@ -62,6 +62,7 @@ extern cl::list<std::string> jsonFields;
 extern cl::opt<std::string> hdrDir;
 extern cl::opt<std::string> hdrFile;
 extern cl::opt<bool> hdrKeepAllBodies;
+extern cl::opt<std::string> mixinFile;
 extern cl::list<std::string> versions;
 extern cl::list<std::string> transitions;
 extern cl::opt<std::string> moduleDeps;

driver/ldmd.cpp

@@ -208,6 +208,7 @@ Where:\n\
 #endif
 "  -mcpu=<id>       generate instructions for architecture identified by 'id'\n\
   -mcpu=?          list all architecture options\n\
+  -mixin=<filename>  expand and save mixins to file specified by <filename>\n\
   -mscrtlib=<name> MS C runtime library to reference from main/WinMain/DllMain\n\
   -mv=<package.module>=<filespec>  use <filespec> as source file for <package.module>\n\
   -noboundscheck   no array bounds checking (deprecated, use -boundscheck=off)\n\
@@ -423,7 +424,8 @@ void translateArgs(size_t originalArgc, char **originalArgv,
       else if (strcmp(p + 1, "m32mscoff") == 0) {
         ldcArgs.push_back("-m32");
       }
-      /* -mscrtlib
+      /* -mixin
+       * -mscrtlib
        */
       else if (strncmp(p + 1, "profile", 7) == 0) {
         if (p[8] == 0) {

driver/main.cpp

@@ -85,6 +85,7 @@ void gendocfile(Module *m);
 
 // In dmd/mars.d
 void generateJson(Modules *modules);
+extern "C" void flushMixins();
 
 using namespace opts;
 
@@ -386,6 +387,14 @@ void parseCommandLine(int argc, char **argv, Strings &sourceFiles,
   global.params.doHdrGeneration |=
       global.params.hdrdir || global.params.hdrname;
 
+  opts::initFromPathString(global.params.mixinFile, mixinFile);
+  if (global.params.mixinFile) {
+    global.params.mixinOut = new OutBuffer;
+    // DMD uses atexit() too, so that the file is written when exiting via
+    // fatal() etc. too.
+    atexit(&flushMixins);
+  }
+
   if (moduleDeps.getNumOccurrences() != 0) {
     global.params.moduleDeps = new OutBuffer;
     if (!moduleDeps.empty())