Add -lld flag for using "bin\lld-link.exe" on Windows

src/build_settings.cpp

@@ -86,6 +86,7 @@ struct BuildContext {
 	bool   no_bounds_check;
 	bool   no_output_files;
 	bool   no_crt;
+	bool   use_lld;
 
 	gbAffinity affinity;
 	isize      thread_count;

src/main.cpp

@@ -213,6 +213,7 @@ enum BuildFlagKind {
 	BuildFlag_CrossLibDir,
 	BuildFlag_NoBoundsCheck,
 	BuildFlag_NoCRT,
+	BuildFlag_UseLLD,
 
 	BuildFlag_COUNT,
 };
@@ -254,6 +255,7 @@ bool parse_build_flags(Array<String> args) {
 	add_flag(&build_flags, BuildFlag_CrossLibDir,       str_lit("cross-lib-dir"),   BuildFlagParam_String);
 	add_flag(&build_flags, BuildFlag_NoBoundsCheck,     str_lit("no-bounds-check"), BuildFlagParam_None);
 	add_flag(&build_flags, BuildFlag_NoCRT,             str_lit("no-crt"),          BuildFlagParam_None);
+	add_flag(&build_flags, BuildFlag_UseLLD,            str_lit("lld"),             BuildFlagParam_None);
 
 	GB_ASSERT(args.count >= 3);
 	Array<String> flag_args = array_slice(args, 3, args.count);
@@ -557,6 +559,10 @@ bool parse_build_flags(Array<String> args) {
 						case BuildFlag_NoCRT:
 							build_context.no_crt = true;
 							break;
+
+						case BuildFlag_UseLLD:
+							build_context.use_lld = true;
+							break;
 						}
 					}
 
@@ -684,7 +690,7 @@ i32 exec_llvm_llc(String output_base) {
 #if defined(GB_SYSTEM_WINDOWS)
 	// For more arguments: http://llvm.org/docs/CommandGuide/llc.html
 	return system_exec_command_line_app("llvm-llc", false,
-		"\"%.*sbin/llc\" \"%.*s.bc\" -filetype=obj -O%d "
+		"\"%.*sbin\\llc\" \"%.*s.bc\" -filetype=obj -O%d "
 		"-o \"%.*s.obj\" "
 		"%.*s "
 		"",
@@ -899,15 +905,17 @@ int main(int arg_count, char **arg_ptr) {
 			link_settings = gb_string_append_fmt(link_settings, "/DLL");
 		} else {
 			link_settings = gb_string_append_fmt(link_settings, "/ENTRY:mainCRTStartup");
+		}
 		if (build_context.no_crt) {
 			link_settings = gb_string_append_fmt(link_settings, " /nodefaultlib");
-			}
+		} else {
+			link_settings = gb_string_append_fmt(link_settings, " /defaultlib:libcmt");
 		}
 
 		if (ir_gen.module.generate_debug_info) {
 			link_settings = gb_string_append_fmt(link_settings, " /DEBUG");
 		}
-
+		if (!build_context.use_lld) { // msvc
 			if (build_context.has_resource) {
 				exit_code = system_exec_command_line_app("msvc-link", true,
 					"rc /nologo /fo \"%.*s.res\" \"%.*s.rc\"",
@@ -921,7 +929,6 @@ int main(int arg_count, char **arg_ptr) {
 
 				exit_code = system_exec_command_line_app("msvc-link", true,
 					"link \"%.*s.obj\" \"%.*s.res\" -OUT:\"%.*s.%s\" %s "
-				"/defaultlib:libcmt "
 					"/nologo /incremental:no /opt:ref /subsystem:CONSOLE "
 					" %.*s "
 					" %s "
@@ -933,7 +940,6 @@ int main(int arg_count, char **arg_ptr) {
 			} else {
 				exit_code = system_exec_command_line_app("msvc-link", true,
 					"link \"%.*s.obj\" -OUT:\"%.*s.%s\" %s "
-				"/defaultlib:libcmt "
 					"/nologo /incremental:no /opt:ref /subsystem:CONSOLE "
 					" %.*s "
 					" %s "
@@ -943,6 +949,19 @@ int main(int arg_count, char **arg_ptr) {
 					link_settings
 				);
 			}
+		} else { // lld
+			exit_code = system_exec_command_line_app("msvc-link", true,
+				"\"%.*s\\bin\\lld-link\" \"%.*s.obj\" -OUT:\"%.*s.%s\" %s "
+				"/nologo /incremental:no /opt:ref /subsystem:CONSOLE "
+				" %.*s "
+				" %s "
+				"",
+				LIT(build_context.ODIN_ROOT),
+				LIT(output_base), LIT(output_base), output_ext,
+				lib_str, LIT(build_context.link_flags),
+				link_settings
+			);
+		}
 
 		if (exit_code != 0) {
 			return exit_code;