| From a67cc1b055cf09f371e2eca544884634a1ccc886 Mon Sep 17 00:00:00 2001 |
| From: Andrey Semashev <andrey.semashev@gmail.com> |
| Date: Sun, 8 Jan 2017 18:09:12 +0300 |
| Subject: [PATCH] Corrected register usage in x86 DCAS asm blocks. |
| |
| In some of the asm blocks eax was modified as a result of cmpxchg8b but that |
| was not reflected in the register constraints. This could cause incorrect code |
| being generated. |
| |
| Fetch from: |
| https://github.com/boostorg/atomic/commit/a67cc1b055cf09f371e2eca544884634a1ccc886 |
| |
| [Adjust github patch to tarball release] |
| Signed-off-by: Jรถrg Krause <joerg.krause@embedded.rocks> |
| --- |
| boost/atomic/detail/ops_gcc_x86_dcas.hpp | 14 ++++++++------ |
| 1 file changed, 8 insertions(+), 6 deletions(-) |
| |
| diff --git a/boost/atomic/detail/ops_gcc_x86_dcas.hpp b/boost/atomic/detail/ops_gcc_x86_dcas.hpp |
| index 2f51182..e356e8c 100644 |
| --- a/boost/atomic/detail/ops_gcc_x86_dcas.hpp |
| +++ b/boost/atomic/detail/ops_gcc_x86_dcas.hpp |
| @@ -73,6 +73,7 @@ struct gcc_dcas_x86 |
| { |
| #if !defined(BOOST_ATOMIC_DETAIL_NO_ASM_IMPLIED_ZERO_DISPLACEMENTS) |
| #if defined(__PIC__) |
| + uint32_t v_lo = (uint32_t)v; |
| uint32_t scratch; |
| __asm__ __volatile__ |
| ( |
| @@ -84,8 +85,8 @@ struct gcc_dcas_x86 |
| "1: lock; cmpxchg8b %[dest]\n\t" |
| "jne 1b\n\t" |
| "movl %[scratch], %%ebx\n\t" |
| - : [scratch] "=m" (scratch), [dest] "=o" (storage) |
| - : [value_lo] "a" ((uint32_t)v), "c" ((uint32_t)(v >> 32)) |
| + : [scratch] "=m" (scratch), [dest] "=o" (storage), [value_lo] "+a" (v_lo) |
| + : "c" ((uint32_t)(v >> 32)) |
| : BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "edx", "memory" |
| ); |
| #else // defined(__PIC__) |
| @@ -103,6 +104,7 @@ struct gcc_dcas_x86 |
| #endif // defined(__PIC__) |
| #else // !defined(BOOST_ATOMIC_DETAIL_NO_ASM_IMPLIED_ZERO_DISPLACEMENTS) |
| #if defined(__PIC__) |
| + uint32_t v_lo = (uint32_t)v; |
| uint32_t scratch; |
| __asm__ __volatile__ |
| ( |
| @@ -115,11 +117,11 @@ struct gcc_dcas_x86 |
| "jne 1b\n\t" |
| "movl %[scratch], %%ebx\n\t" |
| #if !defined(BOOST_ATOMIC_DETAIL_NO_ASM_CONSTRAINT_ALTERNATIVES) |
| - : [scratch] "=m,m" (scratch) |
| - : [value_lo] "a,a" ((uint32_t)v), "c,c" ((uint32_t)(v >> 32)), [dest] "D,S" (&storage) |
| + : [scratch] "=m,m" (scratch), [value_lo] "+a,a" (v_lo) |
| + : "c,c" ((uint32_t)(v >> 32)), [dest] "D,S" (&storage) |
| #else |
| - : [scratch] "=m" (scratch) |
| - : [value_lo] "a" ((uint32_t)v), "c" ((uint32_t)(v >> 32)), [dest] "D" (&storage) |
| + : [scratch] "=m" (scratch), [value_lo] "+a" (v_lo) |
| + : "c" ((uint32_t)(v >> 32)), [dest] "D" (&storage) |
| #endif |
| : BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "edx", "memory" |
| ); |