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[Qemu-devel] Re: [PATCH v2 2/2] get rid of hostregs_helper.h
From: |
Blue Swirl |
Subject: |
[Qemu-devel] Re: [PATCH v2 2/2] get rid of hostregs_helper.h |
Date: |
Thu, 18 Feb 2010 23:28:14 +0200 |
Thanks, applied both.
On Thu, Feb 18, 2010 at 10:25 PM, Paolo Bonzini <address@hidden> wrote:
> Since b567b38 (target-arm: remove T0 and T1, 2009-10-16) the only global
> register that is used is AREG0, so the complexity of hostregs_helper.h
> is unused. Use regular assignments and a compiler optimization barrier.
>
> Signed-off-by: Paolo Bonzini <address@hidden>
> ---
> v1->v2: added QEMU prefix to BUILD_BUG_ON
>
> cpu-exec.c | 15 +++++++-----
> hostregs_helper.h | 61
> -----------------------------------------------------
> qemu-common.h | 2 +
> 3 files changed, 11 insertions(+), 67 deletions(-)
> delete mode 100644 hostregs_helper.h
>
> diff --git a/cpu-exec.c b/cpu-exec.c
> index 6a290fd..ab6defc 100644
> --- a/cpu-exec.c
> +++ b/cpu-exec.c
> @@ -210,8 +210,7 @@ static void cpu_handle_debug_exception(CPUState *env)
>
> int cpu_exec(CPUState *env1)
> {
> -#define DECLARE_HOST_REGS 1
> -#include "hostregs_helper.h"
> + host_reg_t saved_env_reg;
> int ret, interrupt_request;
> TranslationBlock *tb;
> uint8_t *tc_ptr;
> @@ -222,9 +221,12 @@ int cpu_exec(CPUState *env1)
>
> cpu_single_env = env1;
>
> - /* first we save global registers */
> -#define SAVE_HOST_REGS 1
> -#include "hostregs_helper.h"
> + /* the access to env below is actually saving the global register's
> + value, so that files not including target-xyz/exec.h are free to
> + use it. */
> + QEMU_BUILD_BUG_ON (sizeof (saved_env_reg) != sizeof (env));
> + saved_env_reg = (host_reg_t) env;
> + asm("");
> env = env1;
>
> #if defined(TARGET_I386)
> @@ -669,7 +671,8 @@ int cpu_exec(CPUState *env1)
> #endif
>
> /* restore global registers */
> -#include "hostregs_helper.h"
> + asm("");
> + env = (void *) saved_env_reg;
>
> /* fail safe : never use cpu_single_env outside cpu_exec() */
> cpu_single_env = NULL;
> diff --git a/hostregs_helper.h b/hostregs_helper.h
> deleted file mode 100644
> index 3a0bece..0000000
> --- a/hostregs_helper.h
> +++ /dev/null
> @@ -1,61 +0,0 @@
> -/*
> - * Save/restore host registers.
> - *
> - * Copyright (c) 2007 CodeSourcery
> - *
> - * This library is free software; you can redistribute it and/or
> - * modify it under the terms of the GNU Lesser General Public
> - * License as published by the Free Software Foundation; either
> - * version 2 of the License, or (at your option) any later version.
> - *
> - * This library is distributed in the hope that it will be useful,
> - * but WITHOUT ANY WARRANTY; without even the implied warranty of
> - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> - * Lesser General Public License for more details.
> - *
> - * You should have received a copy of the GNU Lesser General Public
> - * License along with this library; if not, see
> <http://www.gnu.org/licenses/>.
> - */
> -
> -/* The GCC global register variable extension is used to reserve some
> - host registers for use by generated code. However only the core parts of
> - the translation engine are compiled with these settings. We must manually
> - save/restore these registers when called from regular code.
> - It is not sufficient to save/restore T0 et. al. as these may be declared
> - with a datatype smaller than the actual register. */
> -
> -#if defined(DECLARE_HOST_REGS)
> -
> -#define DO_REG(REG) \
> - register host_reg_t reg_AREG##REG asm(AREG##REG); \
> - volatile host_reg_t saved_AREG##REG;
> -
> -#elif defined(SAVE_HOST_REGS)
> -
> -#define DO_REG(REG) \
> - __asm__ __volatile__ ("" : "=r" (reg_AREG##REG)); \
> - saved_AREG##REG = reg_AREG##REG;
> -
> -#else
> -
> -#define DO_REG(REG) \
> - reg_AREG##REG = saved_AREG##REG; \
> - __asm__ __volatile__ ("" : : "r" (reg_AREG##REG));
> -
> -#endif
> -
> -#ifdef AREG0
> -DO_REG(0)
> -#endif
> -
> -#ifdef AREG1
> -DO_REG(1)
> -#endif
> -
> -#ifdef AREG2
> -DO_REG(2)
> -#endif
> -
> -#undef SAVE_HOST_REGS
> -#undef DECLARE_HOST_REGS
> -#undef DO_REG
> diff --git a/qemu-common.h b/qemu-common.h
> index b09f717..a98fccd 100644
> --- a/qemu-common.h
> +++ b/qemu-common.h
> @@ -11,6 +11,8 @@
> #define QEMU_WARN_UNUSED_RESULT
> #endif
>
> +#define QEMU_BUILD_BUG_ON(x) typedef char
> __build_bug_on__##__LINE__[(x)?-1:1];
> +
> /* Hack around the mess dyngen-exec.h causes: We need QEMU_NORETURN in files
> that
> cannot include the following headers without conflicts. This condition has
> to be removed once dyngen is gone. */
> --
> 1.6.6
>
>
- [Qemu-devel] [PATCH 0/2] simplify global register save/restore, Paolo Bonzini, 2010/02/10
- [Qemu-devel] [PATCH 1/2] remove dead m68k global register definitions, Paolo Bonzini, 2010/02/10
- [Qemu-devel] [PATCH 2/2] get rid of hostregs_helper.h, Paolo Bonzini, 2010/02/10
- Re: [Qemu-devel] [PATCH 2/2] get rid of hostregs_helper.h, Blue Swirl, 2010/02/18
- [Qemu-devel] [PATCH v2 1/2] remove dead m68k definitions, Paolo Bonzini, 2010/02/18
- [Qemu-devel] [PATCH v2 2/2] get rid of hostregs_helper.h, Paolo Bonzini, 2010/02/18
- [Qemu-devel] Re: [PATCH v2 2/2] get rid of hostregs_helper.h,
Blue Swirl <=
- [Qemu-devel] Re: [PATCH v2 2/2] get rid of hostregs_helper.h, Michael S. Tsirkin, 2010/02/25
- [Qemu-devel] Re: [PATCH v2 2/2] get rid of hostregs_helper.h, Paolo Bonzini, 2010/02/25
- [Qemu-devel] Re: [PATCH v2 2/2] get rid of hostregs_helper.h, Michael S. Tsirkin, 2010/02/25
- [Qemu-devel] Re: [PATCH v2 2/2] get rid of hostregs_helper.h, Paolo Bonzini, 2010/02/25
Re: [Qemu-devel] [PATCH 0/2] simplify global register save/restore, Blue Swirl, 2010/02/13
Re: [Qemu-devel] [PATCH 0/2] simplify global register save/restore, Paul Brook, 2010/02/26