[PATCH, driver] -Wl, passing empty strings to ld

[Jim Wilson <wilson at codesourcery dot com>]

We ran into this problem at Cisco.

% touch tmp.o
% ./xgcc -B./ -Wl, --whole-archive tmp.o
/usr/bin/ld: : No such file: No such file or directory
collect2: ld returned 1 exit status
% ./xgcc -B./ -Wl,--whole-archive, tmp.o
/usr/bin/ld: : No such file: No such file or directory
collect2: ld returned 1 exit status
% ./xgcc -B./ -Wl,,--whole-archive tmp.o
/usr/bin/ld: : No such file: No such file or directory
collect2: ld returned 1 exit status

The problem here is that the gcc driver is parsing the invalid -Wl,
options and ending up with empty strings "" which it then passes on to
ld as input file names.  ld fails to open a file named "", and then
prints an error that contains the string "".  All very useless, and very
confusing if you have a 1000+ character long link command and can't
figure out what is wrong.

The gcc driver should be giving an error for the invalid -Wl, option.

The -Wa, and -Wp, options have the same problem, though I don't see any
way to generate a failure there, since the empty strings get passed
through do_spec which silently drops them.  But I figure these should
still get the same fix anyways for consistency.

This was tested with a make check-gcc, and tested by hand to verify that
it has the right effect.

khazaddum$ sh -x tmp.script
+ touch tmp.o
+ ./xgcc -B./ -Wl, --whole-archive tmp.o
xgcc: argument to '-Wl,' is missing
+ ./xgcc -B./ -Wl,--whole-archive, tmp.o
xgcc: argument to '-Wl,' is missing
+ ./xgcc -B./ -Wl,,--whole-archive tmp.o
xgcc: argument to '-Wl,' is missing
+ touch tmp.s
+ ./xgcc -B./ -Wa, --verbose tmp.s
xgcc: argument to '-Wa,' is missing
+ ./xgcc -B./ -Wa,--verbose, tmp.s
xgcc: argument to '-Wa,' is missing
+ ./xgcc -B./ -Wa,,--verbose tmp.s
xgcc: argument to '-Wa,' is missing
+ touch tmp.c
+ ./xgcc -B./ -Wp, --verbose tmp.c
xgcc: argument to '-Wp,' is missing
+ ./xgcc -B./ -Wp,--verbose, tmp.c
xgcc: argument to '-Wp,' is missing
+ ./xgcc -B./ -Wp,,--verbose tmp.c
xgcc: argument to '-Wp,' is missing
khazaddum$ 

Jim

2010-04-14  James E. Wilson  <wilson@codesourcery.com>

	* gcc.c (process_command): In option parsing for "-Wl,", "-Wa,", and
	"-Wp," , call fatal if we have an empty string as argument.

Index: gcc.c
===================================================================
--- gcc.c	(revision 157804)
+++ gcc.c	(working copy)
@@ -3936,10 +3936,18 @@ process_command (int argc, const char **
 	  for (j = 4; argv[i][j]; j++)
 	    if (argv[i][j] == ',')
 	      {
+		/* Reject empty strings.  */
+		if (j == prev)
+		  fatal ("argument to '-Wa,' is missing");
+
 		add_assembler_option (argv[i] + prev, j - prev);
 		prev = j + 1;
 	      }
 
+	  /* Reject empty strings.  */
+	  if (j == prev)
+	    fatal ("argument to '-Wa,' is missing");
+
 	  /* Record the part after the last comma.  */
 	  add_assembler_option (argv[i] + prev, j - prev);
 	}
@@ -3953,10 +3961,18 @@ process_command (int argc, const char **
 	  for (j = 4; argv[i][j]; j++)
 	    if (argv[i][j] == ',')
 	      {
+		/* Reject empty strings.  */
+		if (j == prev)
+		  fatal ("argument to '-Wp,' is missing");
+
 		add_preprocessor_option (argv[i] + prev, j - prev);
 		prev = j + 1;
 	      }
 
+	  /* Reject empty strings.  */
+	  if (j == prev)
+	    fatal ("argument to '-Wp,' is missing");
+
 	  /* Record the part after the last comma.  */
 	  add_preprocessor_option (argv[i] + prev, j - prev);
 	}
@@ -4451,11 +4467,20 @@ process_command (int argc, const char **
 	  for (j = 4; argv[i][j]; j++)
 	    if (argv[i][j] == ',')
 	      {
+		/* Reject empty strings.  */
+		if (j == prev)
+		  fatal ("argument to '-Wl,' is missing");
+
 		infiles[n_infiles].language = "*";
 		infiles[n_infiles++].name
 		  = save_string (argv[i] + prev, j - prev);
 		prev = j + 1;
 	      }
+
+	  /* Reject empty strings.  */
+	  if (j == prev)
+	    fatal ("argument to '-Wl,' is missing");
+
 	  /* Record the part after the last comma.  */
 	  infiles[n_infiles].language = "*";
 	  infiles[n_infiles++].name = argv[i] + prev;