make params an out parameter (dlang#21430)

Author: WalterBright

compiler/src/dmd/globals.d

@@ -392,13 +392,10 @@ extern (C++) struct Global
         errorSinkNull = new ErrorSinkNull;
 
         this.fileManager = new FileManager();
+
         version (MARS)
         {
             compileEnv.vendor = "Digital Mars D";
-
-            // -color=auto is the default value
-            import dmd.console : detectTerminal, detectColorPreference;
-            params.v.color = detectTerminal() && detectColorPreference();
         }
         else version (IN_GCC)
         {
@@ -407,12 +404,10 @@ extern (C++) struct Global
         else version (IN_LLVM)
         {
             compileEnv.vendor = "LDC";
-
-            import dmd.console : detectTerminal;
-            params.v.color = detectTerminal();
         }
+        else
+            static assert(0, "unknown vendor");
 
-        params.v.errorPrintMode = ErrorPrintMode.printErrorContext; // Enable error context globally by default
         compileEnv.versionNumber = parseVersionNumber(versionString());
 
         /* Initialize date, time, and timestamp

compiler/src/dmd/main.d

@@ -164,11 +164,12 @@ private:
  * Params:
  *   argc = Number of arguments passed via command line
  *   argv = Array of string arguments passed via command line
+ *   params = set based on argc, argv
  *
  * Returns:
  *   Application return code
  */
-private int tryMain(size_t argc, const(char)** argv, ref Param params)
+private int tryMain(size_t argc, const(char)** argv, out Param params)
 {
     import dmd.common.charactertables;
     import dmd.sarif;
@@ -195,9 +196,9 @@ private int tryMain(size_t argc, const(char)** argv, ref Param params)
     if (parseCommandlineAndConfig(argc, argv, params, files))
         return EXIT_FAILURE;
 
-    global.compileEnv.previewIn        = global.params.previewIn;
-    global.compileEnv.transitionIn     = global.params.v.vin;
-    global.compileEnv.ddocOutput       = global.params.ddoc.doOutput;
+    global.compileEnv.previewIn        = params.previewIn;
+    global.compileEnv.transitionIn     = params.v.vin;
+    global.compileEnv.ddocOutput       = params.ddoc.doOutput;
 
     final switch(global.params.cIdentifierTable)
     {
@@ -880,7 +881,7 @@ private int tryMain(size_t argc, const(char)** argv, ref Param params)
  *   files = files from argv
  * Returns: true on failure
  */
-bool parseCommandlineAndConfig(size_t argc, const(char)** argv, ref Param params, ref Strings files)
+bool parseCommandlineAndConfig(size_t argc, const(char)** argv, out Param params, ref Strings files)
 {
     // Detect malformed input
     static bool badArgs()
@@ -903,7 +904,7 @@ bool parseCommandlineAndConfig(size_t argc, const(char)** argv, ref Param params
         error(Loc.initial, "cannot open response file '%s'", missingFile);
     //for (size_t i = 0; i < arguments.length; ++i) printf("arguments[%d] = '%s'\n", i, arguments[i]);
     // Set default values
-    params.argv0 = arguments[0].toDString;
+    auto argv0 = arguments[0].toDString;
 
     version (Windows)
         enum iniName = "sc.ini";
@@ -922,7 +923,7 @@ bool parseCommandlineAndConfig(size_t argc, const(char)** argv, ref Param params
     }
     else
     {
-        global.inifilename = findConfFile(params.argv0, iniName);
+        global.inifilename = findConfFile(argv0, iniName);
     }
     // Read the configuration file
     OutBuffer inifileBuffer;

compiler/src/dmd/mars.d

@@ -489,11 +489,28 @@ extern(C) void flushMixins()
  *      true if errors in command line
  */
 
-bool parseCommandLine(const ref Strings arguments, const size_t argc, ref Param params, ref Strings files,
+bool parseCommandLine(const ref Strings arguments, const size_t argc, out Param params, ref Strings files,
                       ref Target target, ref DMDparams driverParams, ErrorSink eSink)
 {
     bool errors;
 
+    // set defaults for params
+    params.v.errorPrintMode = ErrorPrintMode.printErrorContext;
+    version (IN_GCC)
+    {
+    }
+    else version (IN_LLVM)
+    {
+        import dmd.console : detectTerminal;
+        params.v.color = detectTerminal();
+    }
+    else // MARS
+    {
+        // -color=auto is the default value
+        import dmd.console : detectTerminal, detectColorPreference;
+        params.v.color = detectTerminal() && detectColorPreference();
+    }
+
     void error(Args ...)(const(char)* format, Args args)
     {
         eSink.error(Loc.initial, format, args);
@@ -624,6 +641,7 @@ bool parseCommandLine(const ref Strings arguments, const size_t argc, ref Param
 
     files.reserve(arguments.length - 1);
 
+    params.argv0 = toDString(arguments[0]);
     for (size_t i = 1; i < arguments.length; i++)
     {
         const(char)* p = arguments[i];