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Re: [Qemu-devel] [PATCH] tcg: Initialize return value after exit_atomic
From: |
Nikunj A Dadhania |
Subject: |
Re: [Qemu-devel] [PATCH] tcg: Initialize return value after exit_atomic |
Date: |
Wed, 26 Apr 2017 17:08:28 +0530 |
User-agent: |
Notmuch/0.24.1 (https://notmuchmail.org) Emacs/25.1.1 (x86_64-redhat-linux-gnu) |
Richard Henderson <address@hidden> writes:
> Users of tcg_gen_atomic_cmpxchg and do_atomic_op rightfully utilize
> the output. Even though this code is dead, it gets translated, and
> without the initialization we encounter a tcg_error.
>
> Reported-by: Nikunj A Dadhania <address@hidden>
> Signed-off-by: Richard Henderson <address@hidden>
Tested-by: Nikunj A Dadhania <address@hidden>
> ---
> tcg/tcg-op.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/tcg/tcg-op.c b/tcg/tcg-op.c
> index 95a39b7..6b1f415 100644
> --- a/tcg/tcg-op.c
> +++ b/tcg/tcg-op.c
> @@ -2861,6 +2861,9 @@ void tcg_gen_atomic_cmpxchg_i64(TCGv_i64 retv, TCGv
> addr, TCGv_i64 cmpv,
> #endif
> #else
> gen_helper_exit_atomic(tcg_ctx.tcg_env);
> + /* Produce a result, so that we have a well-formed opcode stream
> + with respect to uses of the result in the (dead) code following.
> */
> + tcg_gen_movi_i64(retv, 0);
> #endif /* CONFIG_ATOMIC64 */
> } else {
> TCGv_i32 c32 = tcg_temp_new_i32();
> @@ -2966,6 +2969,9 @@ static void do_atomic_op_i64(TCGv_i64 ret, TCGv addr,
> TCGv_i64 val,
> #endif
> #else
> gen_helper_exit_atomic(tcg_ctx.tcg_env);
> + /* Produce a result, so that we have a well-formed opcode stream
> + with respect to uses of the result in the (dead) code following.
> */
> + tcg_gen_movi_i64(ret, 0);
> #endif /* CONFIG_ATOMIC64 */
> } else {
> TCGv_i32 v32 = tcg_temp_new_i32();
> --
> 2.9.3
Re: [Qemu-devel] [PATCH] tcg: Initialize return value after exit_atomic,
Nikunj A Dadhania <=
Re: [Qemu-devel] [PATCH] tcg: Initialize return value after exit_atomic, Peter Maydell, 2017/04/26