> -----Original Message-----
> From: Brian Cain <brian.c...@oss.qualcomm.com>
> Sent: Monday, April 7, 2025 1:27 PM
> To: qemu-devel@nongnu.org
> Cc: brian.c...@oss.qualcomm.com; richard.hender...@linaro.org;
> phi...@linaro.org; matheus.bernard...@oss.qualcomm.com; a...@rev.ng;
> a...@rev.ng; marco.lie...@oss.qualcomm.com; ltaylorsimp...@gmail.com;
> alex.ben...@linaro.org; quic_mbur...@quicinc.com;
> sidn...@quicinc.com
> Subject: [PATCH v3 5/5] target/hexagon: Remove unreachable
>
> We should raise an exception in the event that we encounter a packet that
> can't be correctly decoded, not fault.
>
> Signed-off-by: Brian Cain <brian.c...@oss.qualcomm.com>
> ---
> target/hexagon/decode.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/target/hexagon/decode.c b/target/hexagon/decode.c index
> b5ece60450..1db7f1950f 100644
> --- a/target/hexagon/decode.c
> +++ b/target/hexagon/decode.c
> @@ -489,7 +489,6 @@ decode_insns(DisasContext *ctx, Insn *insn, uint32_t
> encoding)
> insn->iclass = iclass_bits(encoding);
> return 1;
> }
> - g_assert_not_reached();
> } else {
> uint32_t iclass = get_duplex_iclass(encoding);
> unsigned int slot0_subinsn = get_slot0_subinsn(encoding); @@ -512,6
> +511,11 @@ decode_insns(DisasContext *ctx, Insn *insn, uint32_t encoding)
> }
> g_assert_not_reached();
Why leave this one rather than raising an exception?
> }
> + /*
> + * invalid/unrecognized opcode; return 1 and let gen_insn() raise an
> + * exception when it sees this empty insn.
> + */
> + return 1;
You should set insn->generate to NULL if you want to guarantee that gen_insn
will raise an exception. A better option is to return a special value that
indicates "invalid" and have decode_packet return 0 which will cause
decode_and_translate_packet to generate the exception before generating the
code for any other instructions in the packet.
Do you have a test case for this?
Taylor
