Re: [PATCH] Fix crash with --help=^ (PR driver/71063)

[Marek Polacek <polacek@redhat.com>]

On Wed, May 11, 2016 at 10:50:55PM +0200, Jakub Jelinek wrote:
> On Wed, May 11, 2016 at 10:40:36PM +0200, Marek Polacek wrote:
> > We crashed when given --help=^ and Kyrill explained why in the PR
> > (<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71063#c2>).  The following
> > seems as good a fix as any, I think.
> > 
> > Bootstrapped/regtested on x86_64-linux, ok for trunk?
> > 
> > 2016-05-11  Marek Polacek  <polacek@redhat.com>
> > 
> > 	PR driver/71063
> > 	* opts.c (common_handle_option): Detect missing argument for --help^.
> > 
> > 	* gcc.dg/opts-7.c: New test.
> 
> Ok.  But while touching this, can you fix the formatting around too?
> space between * and a, or ++ a, or & exclude_flags?

Happy to.  I've fixed the whole OPT__help_ case:

Bootstrapped/regtested on x86_64-linux, applying to trunk.

2016-05-12  Marek Polacek  <polacek@redhat.com>

	PR driver/71063
	* opts.c (common_handle_option): Detect missing argument for --help^.

	* gcc.dg/opts-7.c: New test.

diff --git gcc/opts.c gcc/opts.c
index 0f9431a..63d41ca 100644
--- gcc/opts.c
+++ gcc/opts.c
@@ -1595,7 +1595,7 @@ common_handle_option (struct gcc_options *opts,
 
     case OPT__help_:
       {
-	const char * a = arg;
+	const char *a = arg;
 	unsigned int include_flags = 0;
 	/* Note - by default we include undocumented options when listing
 	   specific classes.  If you only want to see documented options
@@ -1612,11 +1612,11 @@ common_handle_option (struct gcc_options *opts,
 	   arg = [^]{word}[,{arg}]
 	   word = {optimizers|target|warnings|undocumented|
 		   params|common|<language>}  */
-	while (* a != 0)
+	while (*a != 0)
 	  {
 	    static const struct
 	    {
-	      const char * string;
+	      const char *string;
 	      unsigned int flag;
 	    }
 	    specifics[] =
@@ -1631,19 +1631,24 @@ common_handle_option (struct gcc_options *opts,
 	      { "common", CL_COMMON },
 	      { NULL, 0 }
 	    };
-	    unsigned int * pflags;
-	    const char * comma;
+	    unsigned int *pflags;
+	    const char *comma;
 	    unsigned int lang_flag, specific_flag;
 	    unsigned int len;
 	    unsigned int i;
 
-	    if (* a == '^')
+	    if (*a == '^')
 	      {
-		++ a;
-		pflags = & exclude_flags;
+		++a;
+		if (*a == '\0')
+		  {
+		    error_at (loc, "missing argument to %qs", "--help=^");
+		    break;
+		  }
+		pflags = &exclude_flags;
 	      }
 	    else
-	      pflags = & include_flags;
+	      pflags = &include_flags;
 
 	    comma = strchr (a, ',');
 	    if (comma == NULL)
@@ -1680,7 +1685,7 @@ common_handle_option (struct gcc_options *opts,
 	    if (specific_flag != 0)
 	      {
 		if (lang_flag == 0)
-		  * pflags |= specific_flag;
+		  *pflags |= specific_flag;
 		else
 		  {
 		    /* The option's argument matches both the start of a
@@ -1689,7 +1694,7 @@ common_handle_option (struct gcc_options *opts,
 		       specified "--help=c", but otherwise we have to issue
 		       a warning.  */
 		    if (strncasecmp (a, "c", len) == 0)
-		      * pflags |= lang_flag;
+		      *pflags |= lang_flag;
 		    else
 		      warning_at (loc, 0,
 				  "--help argument %q.*s is ambiguous, "
@@ -1698,7 +1703,7 @@ common_handle_option (struct gcc_options *opts,
 		  }
 	      }
 	    else if (lang_flag != 0)
-	      * pflags |= lang_flag;
+	      *pflags |= lang_flag;
 	    else
 	      warning_at (loc, 0,
 			  "unrecognized argument to --help= option: %q.*s",
diff --git gcc/testsuite/gcc.dg/opts-7.c gcc/testsuite/gcc.dg/opts-7.c
index e69de29..c54d0b8 100644
--- gcc/testsuite/gcc.dg/opts-7.c
+++ gcc/testsuite/gcc.dg/opts-7.c
@@ -0,0 +1,6 @@
+/* PR driver/71063 */
+/* Test we don't ICE.  */
+/* { dg-do compile } */
+/* { dg-options "--help=^" } */
+
+/* { dg-error "missing argument to" "" { target *-*-* } 0 } */

	Marek