Skip to content

Instantly share code, notes, and snippets.

@real-or-random
Last active September 27, 2020 14:09
  • Star 0 You must be signed in to star a gist
  • Fork 0 You must be signed in to fork a gist
Star You must be signed in to star a gist
Save real-or-random/1548239059158370416dfdc6a866329a to your computer and use it in GitHub Desktop.
From dcc2606d510cc382fd2a9ab387ac99f2423d3973 Mon Sep 17 00:00:00 2001
From: Tim Ruffing <crypto@timruffing.de>
Date: Fri, 25 Sep 2020 11:51:43 +0200
Subject: [PATCH] HACK: Warn for bug 95189
---
gcc/builtins.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/gcc/builtins.c b/gcc/builtins.c
index 53bae599d3e..0935a668570 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -7663,6 +7663,14 @@ inline_expand_builtin_string_cmp (tree exp, rtx target)
machine_mode mode = TYPE_MODE (TREE_TYPE (exp));
+ /* HACK */
+ if (fcode == BUILT_IN_MEMCMP && length < len3)
+ {
+ location_t loc = EXPR_HAS_LOCATION(exp) ? EXPR_LOCATION (exp) : UNKNOWN_LOCATION;
+ loc = expansion_point_location_if_in_system_header(loc);
+ emit_diagnostic(DK_DEBUG, loc, 0, "Potentially miscompiled memcmp");
+ }
+
/* Now, start inline expansion the call. */
return inline_string_cmp (target, (const_str_n == 1) ? arg2 : arg1,
(const_str_n == 1) ? src_str1 : src_str2, length,
--
2.28.0
@real-or-random
Copy link
Author

coauthored by @roconnor-blockstream

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment