Merge pull request git-for-windows#1915 from dscho/open-in-gdb

Add a helper function to start GDB that was already attached to the current process

Author: dscho

compat/mingw.c

@@ -14,6 +14,19 @@
 
 #define HCAST(type, handle) ((type)(intptr_t)handle)
 
+void open_in_gdb(void)
+{
+	static struct child_process cp = CHILD_PROCESS_INIT;
+	extern char *_pgmptr;
+
+	argv_array_pushl(&cp.args, "mintty", "gdb", NULL);
+	argv_array_pushf(&cp.args, "--pid=%d", getpid());
+	cp.clean_on_exit = 1;
+	if (start_command(&cp) < 0)
+		die_errno("Could not start gdb");
+	sleep(1);
+}
+
 int err_win_to_posix(DWORD winerr)
 {
 	int error = ENOSYS;

compat/mingw.h

@@ -691,6 +691,16 @@ extern CRITICAL_SECTION pinfo_cs;
 int wmain(int argc, const wchar_t **w_argv);
 int main(int argc, const char **argv);
 
+/*
+ * For debugging: if a problem occurs, say, in a Git process that is spawned
+ * from another Git process which in turn is spawned from yet another Git
+ * process, it can be quite daunting to figure out what is going on.
+ *
+ * Call this function to open a new MinTTY (this assumes you are in Git for
+ * Windows' SDK) with a GDB that attaches to the current process right away.
+ */
+extern void open_in_gdb(void);
+
 /*
  * Used by Pthread API implementation for Windows
  */