Mesa (master): glcpp: Fix post-decrement underflow in loop-control variable

[Carl Worth]

Module: Mesa
Branch: master
Commit: d8eeb1d330c52aad734cc553e41b457e6727275c
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=d8eeb1d330c52aad734cc553e41b457e6727275c

Author: Carl Worth <cworth at cworth.org>
Date:   Mon Jun  3 11:35:43 2013 -0700

glcpp: Fix post-decrement underflow in loop-control variable

This loop-control condition with a post-decrement operator would lead to
an underflow of collapsed_newlines. This in turn would cause a subsequent
execution of the loop to labor inordinately trying to return the loop-control
variable to a value of 0 again.

Fix this by dis-intertwining the test and the decrement.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=65112

Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>

---

 src/glsl/glcpp/pp.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/src/glsl/glcpp/pp.c b/src/glsl/glcpp/pp.c
index 789f7f9..7e1b6c6 100644
--- a/src/glsl/glcpp/pp.c
+++ b/src/glsl/glcpp/pp.c
@@ -97,8 +97,10 @@ remove_line_continuations(glcpp_parser_t *ctx, const char *shader)
 			{
 				ralloc_strncat(&clean, shader,
 					       newline - shader + 1);
-				while (collapsed_newlines--)
+				while (collapsed_newlines) {
 					ralloc_strcat(&clean, "\n");
+					collapsed_newlines--;
+				}
 				shader = newline + 1;
 				search_start = shader;
 			}