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| author | Marko Mäkelä <marko.makela@mariadb.com> | 2019-08-12 14:05:26 +0300 |
|---|---|---|
| committer | Marko Mäkelä <marko.makela@mariadb.com> | 2019-08-12 14:14:17 +0300 |
| commit | b2a387a3f1a0603482d184241979f0172cba45cf (patch) | |
| tree | 68bd7dd766840982483b002a27c4743a4f5ab49c | |
| parent | cabf10b640980fae6051a2a0f20b9b2b0c4143ce (diff) | |
| download | mariadb-git-b2a387a3f1a0603482d184241979f0172cba45cf.tar.gz | |
Document TRASH_FILL, TRASH_ALLOC, TRASH_FREE
| -rw-r--r-- | include/my_valgrind.h | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/include/my_valgrind.h b/include/my_valgrind.h index ad22f0cad40..7a56b28c0f0 100644 --- a/include/my_valgrind.h +++ b/include/my_valgrind.h @@ -1,4 +1,4 @@ -/* Copyright (C) 2010 Monty Program Ab +/* Copyright (C) 2010, 2019, MariaDB Corporation. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -55,11 +55,19 @@ https://github.com/google/sanitizers/wiki/AddressSanitizerManualPoisoning */ #endif /* HAVE_VALGRIND */ #ifndef DBUG_OFF +/* NOTE: Do not invoke TRASH_FILL directly! Use TRASH_ALLOC or TRASH_FREE. + +The MEM_UNDEFINED() call before memset() is for canceling the effect +of any previous MEM_NOACCESS(). We must invoke MEM_UNDEFINED() after +writing the dummy pattern, unless MEM_NOACCESS() is going to be invoked. +On AddressSanitizer, the MEM_UNDEFINED() in TRASH_ALLOC() has no effect. */ #define TRASH_FILL(A,B,C) do { const size_t trash_tmp= (B); MEM_UNDEFINED(A, trash_tmp); memset(A, C, trash_tmp); } while (0) #else #define TRASH_FILL(A,B,C) do { MEM_UNDEFINED((A), (B)); } while (0) #endif +/** Note that some memory became allocated or uninitialized. */ #define TRASH_ALLOC(A,B) do { TRASH_FILL(A,B,0xA5); MEM_UNDEFINED(A,B); } while(0) +/** Note that some memory became freed. (Prohibit further access to it.) */ #define TRASH_FREE(A,B) do { TRASH_FILL(A,B,0x8F); MEM_NOACCESS(A,B); } while(0) #endif /* MY_VALGRIND_INCLUDED */ |