diff options
| author | Carl Worth <[email protected]> | 2014-08-18 11:36:12 -0700 |
|---|---|---|
| committer | Carl Worth <[email protected]> | 2014-08-22 15:14:59 -0700 |
| commit | 23163df24cf96107ee8ccb372db20f49e9d88948 (patch) | |
| tree | aa3d2942a5db222bbc20a19c6a37bf3e15b4e515 /src/glsl/glcpp | |
| parent | 97d03b9366bfa55b27feb92aa5afacd9c5f6f421 (diff) | |
glcpp: Don't use alternation in the lookahead for empty pragmas.
We've found that there's a buffer overrun bug in flex that's triggered by
using alternation in a lookahead pattern.
Fortunately, we don't need to match the exact {NEWLINE} expression to
detect an empty pragma. It suffices to verify that there are no non-space
characters before any newline character. So we can use a simple [\r\n] to
get the desired behavior while avoiding the flex bug.
Fixes the regression of piglit's 17000-consecutive-chars-identifier test,
(which has been crashing since commit
04e40fd337a244ee77ef9553985e9398ff0344af ).
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=82472
Signed-off-by: Carl Worth <[email protected]>
Reviewed-by: Kenneth Graunke <[email protected]>
CC: <[email protected]>
Diffstat (limited to 'src/glsl/glcpp')
| -rw-r--r-- | src/glsl/glcpp/glcpp-lex.l | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/src/glsl/glcpp/glcpp-lex.l b/src/glsl/glcpp/glcpp-lex.l index 98d500ec0be..fa9aa506912 100644 --- a/src/glsl/glcpp/glcpp-lex.l +++ b/src/glsl/glcpp/glcpp-lex.l @@ -289,8 +289,14 @@ HEXADECIMAL_INTEGER 0[xX][0-9a-fA-F]+[uU]? } /* Swallow empty #pragma directives, (to avoid confusing the - * downstream compiler). */ -<HASH>pragma{HSPACE}*/{NEWLINE} { + * downstream compiler). + * + * Note: We use a simple regular expression for the lookahead + * here. Specifically, we cannot use the complete {NEWLINE} expression + * since it uses alternation and we've found that there's a flex bug + * where using alternation in the lookahead portion of a pattern + * triggers a buffer overrun. */ +<HASH>pragma{HSPACE}*/[\r\n] { BEGIN INITIAL; } |