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authorAlan Modra <amodra@gmail.com>2019-12-16 16:58:30 +1030
committerAlan Modra <amodra@gmail.com>2019-12-16 17:35:13 +1030
commitf81e7e2db6d1aaf47561e54356aee12b585533c2 (patch)
tree53524a5a7c584b514762e5cd1ca94c40044e2bf2 /opcodes/aarch64-dis.c
parent488d02fe7729dda5b9414a3942df68e0c316ce53 (diff)
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ubsan: aarch64: left shift of negative value
* aarch64-dis.c (sign_extend): Return uint64_t. Rewrite without conditional. (aarch64_ext_imm): Avoid signed overflow.
Diffstat (limited to 'opcodes/aarch64-dis.c')
-rw-r--r--opcodes/aarch64-dis.c15
1 files changed, 6 insertions, 9 deletions
diff --git a/opcodes/aarch64-dis.c b/opcodes/aarch64-dis.c
index 8b32097..abed2d8 100644
--- a/opcodes/aarch64-dis.c
+++ b/opcodes/aarch64-dis.c
@@ -178,18 +178,15 @@ extract_all_fields (const aarch64_operand *self, aarch64_insn code)
}
/* Sign-extend bit I of VALUE. */
-static inline int32_t
+static inline uint64_t
sign_extend (aarch64_insn value, unsigned i)
{
- uint32_t ret = value;
+ uint64_t ret, sign;
assert (i < 32);
- if ((value >> i) & 0x1)
- {
- uint32_t val = (uint32_t)(-1) << i;
- ret = ret | val;
- }
- return (int32_t) ret;
+ ret = value;
+ sign = (uint64_t) 1 << i;
+ return ((ret & (sign + sign - 1)) ^ sign) - sign;
}
/* N.B. the following inline helpfer functions create a dependency on the
@@ -658,7 +655,7 @@ aarch64_ext_imm (const aarch64_operand *self, aarch64_opnd_info *info,
const aarch64_inst *inst ATTRIBUTE_UNUSED,
aarch64_operand_error *errors ATTRIBUTE_UNUSED)
{
- int64_t imm;
+ uint64_t imm;
imm = extract_all_fields (self, code);