Fix wat2wasm -o - for writing to stdout. NFC (#2638)

Fixes: #2637

Author: sbc100

src/option-parser.cc

@@ -208,7 +208,8 @@ void OptionParser::Parse(int argc, char* argv[]) {
             arg[best_length + 2] == '=') {  // +2 to skip "--".
           option_argument = &arg[best_length + 3];
         } else {
-          if (i + 1 == argc || argv[i + 1][0] == '-') {
+          if (i + 1 == argc ||
+              (argv[i + 1][0] == '-' && strlen(argv[i + 1]) > 1)) {
             Errorf("option '--%s' requires argument",
                    best_option.long_name.c_str());
             continue;
@@ -240,7 +241,8 @@ void OptionParser::Parse(int argc, char* argv[]) {
                 break;
               }
 
-              if (i + 1 == argc || argv[i + 1][0] == '-') {
+              if (i + 1 == argc ||
+                  (argv[i + 1][0] == '-' && strlen(argv[i + 1]) > 1)) {
                 Errorf("option '-%c' requires argument", option.short_name);
                 break;
               }

test/run-tests.py

@@ -265,6 +265,13 @@ def Run(self, cwd, timeout, console_out=False, env=None):
         process = None
         is_timeout = Cell(False)
 
+        cmd = self.args
+        stdout_filename = None
+        # Hacky support for stdout redirection `cmd > output`
+        if len(cmd) > 2 and cmd[-2] == '>':
+            stdout_filename = os.path.join(cwd, cmd[-1])
+            cmd = cmd[:-2]
+
         def KillProcess(timeout=True):
             if process:
                 try:
@@ -289,7 +296,7 @@ def KillProcess(timeout=True):
 
             # http://stackoverflow.com/a/10012262: subprocess with a timeout
             # http://stackoverflow.com/a/22582602: kill subprocess and children
-            process = subprocess.Popen(self.args, cwd=cwd, env=env,
+            process = subprocess.Popen(cmd, cwd=cwd, env=env,
                                        stdout=None if console_out else subprocess.PIPE,
                                        stderr=None if console_out else subprocess.PIPE,
                                        stdin=None if not self.stdin else subprocess.PIPE,
@@ -310,6 +317,10 @@ def KillProcess(timeout=True):
         finally:
             KillProcess(False)
 
+        if stdout_filename:
+            open(stdout_filename, 'wb').write(stdout)
+            stdout = None
+
         return RunResult(self, stdout, stderr, returncode, duration)
 
     def __str__(self):

test/wat2wasm_stdout.txt

@@ -0,0 +1,11 @@
+;;; TOOL: wat2wasm
+;;; ARGS: -o - > %(temp_file)s_tmp.wasm
+;;; RUN: %(wasm2wat)s %(temp_file)s_tmp.wasm
+(module
+  (func)
+)
+(;; STDOUT ;;;
+(module
+  (type (;0;) (func))
+  (func (;0;) (type 0)))
+;;; STDOUT ;;)