Re: [Qemu-devel] [PATCH v14 07/34] target/arm: Set is_jmp properly after single-stepping

["Emilio G. Cota" <cota@braap.org>]

On Fri, Jul 14, 2017 at 23:42:16 -1000, Richard Henderson wrote:
> We have generated an exception, so use DISAS_NORETURN.
> 
> Signed-off-by: Richard Henderson <rth@twiddle.net>
> ---
>  target/arm/translate-a64.c | 1 +
>  target/arm/translate.c     | 4 +++-
>  2 files changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c
> index 342ff7c..657684b 100644
> --- a/target/arm/translate-a64.c
> +++ b/target/arm/translate-a64.c
> @@ -11285,6 +11285,7 @@ void gen_intermediate_code_a64(CPUState *cs, TranslationBlock *tb)
>                          dc->is_jmp = DISAS_UPDATE;
>                      } else {
>                          gen_exception_internal_insn(dc, 0, EXCP_DEBUG);
> +                        dc->is_jmp = DISAS_NORETURN;
>                          /* The address covered by the breakpoint must be
>                             included in [tb->pc, tb->pc + tb->size) in order
>                             to for it to be properly cleared -- thus we
> diff --git a/target/arm/translate.c b/target/arm/translate.c
> index 2ae68ce..83e5491 100644
> --- a/target/arm/translate.c
> +++ b/target/arm/translate.c
> @@ -11942,6 +11942,7 @@ void gen_intermediate_code(CPUState *cs, TranslationBlock *tb)
>                          dc->is_jmp = DISAS_UPDATE;
>                      } else {
>                          gen_exception_internal_insn(dc, 0, EXCP_DEBUG);
> +                        dc->is_jmp = DISAS_NORETURN;

gen_exception_internal_insn already sets dc->is_jmp to DISAS_NORETURN,
as per patch 04/34:
@@ -304,7 +304,7 @@ static void gen_exception_internal_insn(DisasContext *s, int offset, int excp)
 {
     gen_a64_set_pc_im(s->pc - offset);
     gen_exception_internal(excp);
-    s->is_jmp = DISAS_EXC;
+    s->is_jmp = DISAS_NORETURN;
 }

This applies to both arm and a64.

Why do we need to set is_jmp again, then?

		E.