target/arm: Assert immh != 0 in disas_simd_shift_imm

Coverity raised a shed-load of errors cascading from inferring
that clz32(immh) might yield 32, from immh might be 0.

While immh cannot be 0 from encoding, it is not obvious even to
a human how we've checked that: via the filtering provided by
data_proc_simd[].

Reported-by: Coverity (CID 1421923, and more)
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20200320160622.8040-3-richard.henderson@linaro.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Richard Henderson 2020-03-23 17:22:30 +00:00 committed by Peter Maydell
parent ae1111d4de
commit 3944d58db3
1 changed files with 3 additions and 0 deletions

View File

@ -10405,6 +10405,9 @@ static void disas_simd_shift_imm(DisasContext *s, uint32_t insn)
bool is_u = extract32(insn, 29, 1);
bool is_q = extract32(insn, 30, 1);
/* data_proc_simd[] has sent immh == 0 to disas_simd_mod_imm. */
assert(immh != 0);
switch (opcode) {
case 0x08: /* SRI */
if (!is_u) {