Improvements to the gcc wrapper

Add some comments and better error reporting

1 files changed, 21 insertions, 8 deletions

diff --git a/driver/gcc/gcc.c b/driver/gcc/gcc.c
index cd8a511074..c086f748e5 100644
--- a/driver/gcc/gcc.c
+++ b/driver/gcc/gcc.c
@@ -1,12 +1,24 @@
 
+/* gcc on mingw is hardcoded to use /mingw (which is c:/mingw) to
+   find various files. If this is a different version of mingw to the
+   one that we have in the GHC tree then things can go wrong. We
+   therefore need to add various -B flags to the gcc commandline,
+   so that it uses our in-tree mingw. Hence this wrapper. */
+
 #include "getLocation.h"
+#include <errno.h>
 #include <process.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdarg.h>
+#include <string.h>
+
+static void die(const char *fmt, ...) {
+    va_list argp;
 
-static void die(char *msg) {
-    fprintf(stderr, "%s", msg);
+    va_start(argp, fmt);
+    vfprintf(stderr, fmt, argp);
+    va_end(argp);
     exit(1);
 }
 
@@ -16,23 +28,24 @@ static char *mkString(const char *fmt, ...) {
     va_list argp;
 
     va_start(argp, fmt);
-    i = vsnprintf(p, 0, fmt, argp);
+    i = vsnprintf(NULL, 0, fmt, argp);
     va_end(argp);
 
     if (i < 0) {
-        die("snprintf failed\n");
+        die("snprintf 0 failed: errno %d: %s\n", errno, strerror(errno));
     }
 
     p = malloc(i + 1);
     if (p == NULL) {
-        die("malloc failed\n");
+        die("malloc failed: errno %d: %s\n", errno, strerror(errno));
     }
 
     va_start(argp, fmt);
     j = vsnprintf(p, i + 1, fmt, argp);
     va_end(argp);
     if (i < 0) {
-        die("snprintf failed\n");
+        die("snprintf with %d failed: errno %d: %s\n",
+            i + 1, errno, strerror(errno));
     }
 
     return p;
@@ -45,7 +58,7 @@ char *quote(char *str) {
 
     quotedStr = malloc(2 * strlen(str) + 2 + 1);
     if (quotedStr == NULL) {
-        die("malloc failed\n");
+        die("malloc failed: errno %d: %s\n", errno, strerror(errno));
     }
     p = quotedStr;
     *p++ = '"';
@@ -89,7 +102,7 @@ int main(int argc, char** argv) {
     // execv(exePath, argv);
     ret = spawnv(_P_WAIT, exePath, (const char* const*)newArgv);
     if (errno) {
-        die("Spawn failed\n");
+        die("spawnv failed: errno %d: %s\n", errno, strerror(errno));
     }
     exit(ret);
 }