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[PATCH 2/3] target/arm: Assert immh != 0 in disas_simd_shift_imm
From: |
Richard Henderson |
Subject: |
[PATCH 2/3] target/arm: Assert immh != 0 in disas_simd_shift_imm |
Date: |
Fri, 20 Mar 2020 09:06:21 -0700 |
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 <address@hidden>
---
target/arm/translate-a64.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c
index 8fffb52203..032478614c 100644
--- a/target/arm/translate-a64.c
+++ b/target/arm/translate-a64.c
@@ -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) {
--
2.20.1