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From: Jivan Hakobyan <>
Cc: Jeff Law <>
Subject: LTO: buffer overflow in lto_output_init_mode_table
Date: Thu, 22 Jun 2023 15:36:51 +0400	[thread overview]
Message-ID: <> (raw)

[-- Attachment #1.1: Type: text/plain, Size: 398 bytes --]

In the case when enabled -flto=N GCC aborted compilation.
The reason is the overflowing streamer_mode_table buffer.
It has 1 << 8 bytes but lto_output_init_mode_table() tries to fill
with MAX_MACHINE_MODE bytes.

       * tree-streamer.h (streamer_mode_table): Changed buffer size
       * (streamer_mode_table): Likewise.

With the best regards
Jivan Hakobyan

[-- Attachment #2: lto.patch --]
[-- Type: text/x-patch, Size: 1232 bytes --]

diff --git a/gcc/ b/gcc/
index ed65a7692e3..a28ef9c7920 100644
--- a/gcc/
+++ b/gcc/
@@ -35,7 +35,7 @@ along with GCC; see the file COPYING3.  If not see
    During streaming in, we translate the on the disk mode using this
    table.  For normal LTO it is set to identity, for ACCEL_COMPILER
    depending on the mode_table content.  */
-unsigned char streamer_mode_table[1 << 8];
+unsigned char streamer_mode_table[MAX_MACHINE_MODE];
 /* Check that all the TS_* structures handled by the streamer_write_* and
    streamer_read_* routines are exactly ALL the structures defined in
diff --git a/gcc/tree-streamer.h b/gcc/tree-streamer.h
index 170d61cf20b..51a292c8d80 100644
--- a/gcc/tree-streamer.h
+++ b/gcc/tree-streamer.h
@@ -75,7 +75,7 @@ void streamer_write_tree_body (struct output_block *, tree);
 void streamer_write_integer_cst (struct output_block *, tree);
 /* In  */
-extern unsigned char streamer_mode_table[1 << 8];
+extern unsigned char streamer_mode_table[MAX_MACHINE_MODE];
 void streamer_check_handled_ts_structures (void);
 bool streamer_tree_cache_insert (struct streamer_tree_cache_d *, tree,
 				 hashval_t, unsigned *);

             reply	other threads:[~2023-06-22 11:37 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-22 11:36 Jivan Hakobyan [this message]
2023-06-22 11:42 ` Robin Dapp
2023-06-22 12:36   ` Jivan Hakobyan

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