From 516d9ef53b656aa5e6eebdc2c09e8d257b13e033 Mon Sep 17 00:00:00 2001
From: Austin Clements <austin@google.com>
Date: Tue, 4 Nov 2014 09:43:37 -0500
Subject: [PATCH] gc: abort if given an unknown debug (-d) flag

The check for unknown command line debug flags in gc was
incorrect: the loop over debugtab terminates when it reaches a
nil entry, but it was only reporting an error if the parser
had passed the last entry of debugtab (which it never did).
Fix this by reporting the usage error if the loop reaches a
nil entry.

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/166110043
---
 src/cmd/gc/lex.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/cmd/gc/lex.c b/src/cmd/gc/lex.c
index 2303b442cd..523ba37aa7 100644
--- a/src/cmd/gc/lex.c
+++ b/src/cmd/gc/lex.c
@@ -344,8 +344,8 @@ main(int argc, char *argv[])
 					break;
 				}
 			}
-			if(j == nelem(debugtab))
-				fatal("unknown debug information -d '%s'\n", f[i]);
+			if(debugtab[j].name == nil)
+				sysfatal("unknown debug information -d '%s'\n", f[i]);
 		}
 	}