[Qemu-devel] [PULL] tcg queued patch

[Qemu-devel] [PULL] tcg queued patch

[Richard Henderson]

Fixes a tcg_error when building with clang on some hosts.


r~


The following changes since commit 51b9d495f2a99c65c9e524c8f6fe283ebfabae1d:

  Revert "COLO-compare: Optimize tcp compare trace event" (2017-04-26 16:19:27 +0100)

are available in the git repository at:

  git://github.com/rth7680/qemu.git tags/pull-tcg-20170426

for you to fetch changes up to 79b1af906245558c30e0a5faf26cb52b63f83cce:

  tcg: Initialize return value after exit_atomic (2017-04-26 19:26:11 +0200)

----------------------------------------------------------------
Fix for exit_atomic tcg opcode paths

----------------------------------------------------------------
Richard Henderson (1):
      tcg: Initialize return value after exit_atomic

 tcg/tcg-op.c | 6 ++++++
 1 file changed, 6 insertions(+)

[Qemu-devel] [PULL] tcg: Initialize return value after exit_atomic

[Richard Henderson]

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 <nikunj@linux.vnet.ibm.com>
Tested-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
Tested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
---
 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] [PULL] tcg queued patch

[Peter Maydell]

On 26 April 2017 at 18:30, Richard Henderson <rth@twiddle.net> wrote:
> Fixes a tcg_error when building with clang on some hosts.
>
>
> r~
>
>
> The following changes since commit 51b9d495f2a99c65c9e524c8f6fe283ebfabae1d:
>
>   Revert "COLO-compare: Optimize tcp compare trace event" (2017-04-26 16:19:27 +0100)
>
> are available in the git repository at:
>
>   git://github.com/rth7680/qemu.git tags/pull-tcg-20170426
>
> for you to fetch changes up to 79b1af906245558c30e0a5faf26cb52b63f83cce:
>
>   tcg: Initialize return value after exit_atomic (2017-04-26 19:26:11 +0200)
>
> ----------------------------------------------------------------
> Fix for exit_atomic tcg opcode paths
>
> ----------------------------------------------------------------
> Richard Henderson (1):
>       tcg: Initialize return value after exit_atomic
>
>  tcg/tcg-op.c | 6 ++++++
>  1 file changed, 6 insertions(+)


Applied, thanks.

-- PMM