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Diffstat (limited to 'toolchain-layer/recipes-devtools/gcc/gcc-4.5/gcc-arm-volatile-bitfield-fix.patch')
| -rw-r--r-- | toolchain-layer/recipes-devtools/gcc/gcc-4.5/gcc-arm-volatile-bitfield-fix.patch | 103 |
1 files changed, 0 insertions, 103 deletions
diff --git a/toolchain-layer/recipes-devtools/gcc/gcc-4.5/gcc-arm-volatile-bitfield-fix.patch b/toolchain-layer/recipes-devtools/gcc/gcc-4.5/gcc-arm-volatile-bitfield-fix.patch deleted file mode 100644 index d5a31d19d8..0000000000 --- a/toolchain-layer/recipes-devtools/gcc/gcc-4.5/gcc-arm-volatile-bitfield-fix.patch +++ /dev/null @@ -1,103 +0,0 @@ -Date: Mon, 22 Nov 2010 13:28:54 +0000 -From: Julian Brown <julian at codesourcery dot com> -To: gcc-patches at gcc dot gnu dot org -Cc: DJ Delorie <dj at redhat dot com> -Subject: [PATCH] Volatile bitfields vs. inline asm memory constraints -Message-ID: <20101122132854.0aca431a@rex.config> -Mime-Version: 1.0 -Content-Type: multipart/mixed; boundary="MP_/ONpW806RnQ1ziaYj7_Y5E27" -X-IsSubscribed: yes -Mailing-List: contact gcc-patches-help at gcc dot gnu dot org; run by ezmlm -Precedence: bulk -List-Id: <gcc-patches.gcc.gnu.org> -List-Archive: <http://gcc.gnu.org/ml/gcc-patches/> -List-Post: <mailto:gcc-patches at gcc dot gnu dot org> -List-Help: <mailto:gcc-patches-help at gcc dot gnu dot org> -Sender: gcc-patches-owner at gcc dot gnu dot org -Delivered-To: mailing list gcc-patches at gcc dot gnu dot org - - - -Hi, - -This patch fixes the issue in the (Launchpad, not GCC) bug tracker: - -https://bugs.launchpad.net/gcc-linaro/+bug/675347 - -The problem was introduced by the patch from DJ to honour volatile -bitfield types: - -http://gcc.gnu.org/ml/gcc-patches/2010-06/msg01167.html - -but not exposed (on ARM) until the option was made the default (on the -Linaro branch) -- it's not yet the default on mainline. - -The issue is as follows: after DJ's patch and with --fstrict-volatile-bitfields, in expr.c:expand_expr_real_1, the if -condition with the comment "In cases where an aligned union has an -unaligned object as a field, we might be extracting a BLKmode value -from an integer-mode (e.g., SImode) object [...]" triggers for a normal -(non-bitfield) volatile field of a struct/class. - -But, this appears to be over-eager: in the particular case mentioned -above, when expanding a "volatile int" struct field used as a memory -constraint for an inline asm, we end up with something which is no -longer addressable (I think because of the actions of -extract_bit_field). So, compilation aborts. - -My proposed fix is to restrict the conditional by only making it execute -for -fstrict-volatile-bitfields only for non-naturally-aligned accesses: -this appears to work (fixes test in question, and no regressions for -cross to ARM Linux, gcc/g++/libstdc++, with -fstrict-volatile-bitfields -turned on), but I don't know if there will be unintended consequences. -DJ, does it look sane to you? - -Incidentally the constraints in the inline asm in the Launchpad -testcase might be slightly dubious (attempting to force (mem (reg)) by -using both "+m" (var) and "r" (&var) constraints), but replacing -them with e.g.: - - asm volatile("0:\n" - "ldrex %[newValue], %[_q_value]\n" - "sub %[newValue], %[newValue], #1\n" - "strex %[result], %[newValue], %[_q_value]\n" - "teq %[result], #0\n" - "bne 0b\n" - : [newValue] "=&r" (newValue), - [result] "=&r" (result) - : [_q_value] "Q" (_q_value) - : "cc", "memory"); - -still leads to a warning (not an error) with trunk and --fstrict-volatile-bitfields: - -atomic-changed.cc:24:35: warning: use of memory input without lvalue in -asm operand 2 is deprecated [enabled by default] - -The warning goes away with the attached patch. So, I don't think the -problem is purely that the original inline asm is invalid. - -OK to apply, or any comments? - -Julian - -ChangeLog - - gcc/ - * expr.c (expand_expr_real_1): Only use BLKmode for volatile - accesses which are not naturally aligned. - -Index: gcc-4_5-branch/gcc/expr.c -=================================================================== ---- gcc-4_5-branch.orig/gcc/expr.c 2010-12-23 00:42:11.690101002 -0800 -+++ gcc-4_5-branch/gcc/expr.c 2010-12-24 15:07:39.400101000 -0800 -@@ -9029,7 +9029,8 @@ - && modifier != EXPAND_INITIALIZER) - /* If the field is volatile, we always want an aligned - access. */ -- || (volatilep && flag_strict_volatile_bitfields > 0) -+ || (volatilep && flag_strict_volatile_bitfields > 0 -+ && (bitpos % GET_MODE_ALIGNMENT (mode) != 0)) - /* If the field isn't aligned enough to fetch as a memref, - fetch it as a bit field. */ - || (mode1 != BLKmode |