Add --werror flag to treat warnings as errors.

The specific need for it was so that tests in tests_errors
can test to see if a desired diagnostic warning is issued
(like ptrcast-lose-info does.)

ispc.cpp

@@ -341,6 +341,7 @@ Globals::Globals() {
     runCPP = true;
     debugPrint = false;
     disableWarnings = false;
+    warningsAsErrors = false;
     disableLineWrap = false;
     emitPerfWarnings = true;
     emitInstrumentation = false;

ispc.h

@@ -348,6 +348,9 @@ struct Globals {
     /** Indicates whether all warning messages should be surpressed. */
     bool disableWarnings;
 
+    /** Indicates whether warnings should be issued as errors. */
+    bool warningsAsErrors;
+
     /** Indicates whether line wrapping of error messages to the terminal
         width should be disabled. */
     bool disableLineWrap;

main.cpp

@@ -104,6 +104,7 @@ static void usage(int ret) {
 #endif // !ISPC_IS_WINDOWS
     printf("    [--target=<isa>]\t\t\tSelect target ISA. <isa>={%s}\n", Target::SupportedTargetISAs());
     printf("    [--version]\t\t\t\tPrint ispc version\n");
+    printf("    [--werror]\t\t\tTreat warnings as errors\n");
     printf("    [--woff]\t\t\t\tDisable warnings\n");
     printf("    [--wno-perf]\t\t\tDon't issue warnings related to performance-related issues\n");
     printf("    <file to compile or \"-\" for stdin>\n");
@@ -283,6 +284,8 @@ int main(int Argc, char *Argv[]) {
             g->disableWarnings = true;
             g->emitPerfWarnings = false;
         }
+        else if (!strcmp(argv[i], "--werror"))
+            g->warningsAsErrors = true;
         else if (!strcmp(argv[i], "--nowrap"))
             g->disableLineWrap = true;
         else if (!strcmp(argv[i], "--wno-perf") || !strcmp(argv[i], "-wno-perf"))

run_tests.py

@@ -107,7 +107,7 @@ def run_tasks_from_queue(queue):
         # is this a test to make sure an error is issued?
         want_error = (filename.find("tests_errors") != -1)
         if want_error == True:
-            ispc_cmd = "ispc --nowrap %s --arch=%s --target=%s" % \
+            ispc_cmd = "ispc --werror --nowrap %s --arch=%s --target=%s" % \
                 (filename, options.arch, options.target)
             sp = subprocess.Popen(shlex.split(ispc_cmd), stdin=None, stdout=subprocess.PIPE,
                                   stderr=subprocess.PIPE)

util.cpp

@@ -291,7 +291,9 @@ Warning(SourcePos p, const char *fmt, ...) {
 
     va_list args;
     va_start(args, fmt);
-    lPrint("Warning", p, fmt, args);
+    lPrint(g->warningsAsErrors ? "Error" : "Warning", p, fmt, args);
+    if (g->warningsAsErrors)
+        ++m->errorCount;
     va_end(args);
 }