On 9/1/21 4:10 PM, Peter Maydell wrote:
In the SSE decode function gen_sse(), we combine a byte 'b' and a value 'b1' which can be [0..3], and switch on them: b |= (b1 << 8); switch (b) { ... default: unknown_op: gen_unknown_opcode(env, s); return; }In three cases inside this switch, we were then also checking for "if (b1 >= 2) { goto unknown_op; }". However, this can never happen, because the 'case' values in each place are 0x0nn or 0x1nn and the switch will have directed the b1 == (2, 3) cases to the default already. This check was added in commit c045af25a52e9 in 2010; the added code was unnecessary then as well, and was apparently intended only to ensure that we never accidentally ended up indexing off the end of an sse_op_table with only 2 entries as a result of future bugs in the decode logic. Change the checks to assert() instead, and make sure they're always immediately before the array access they are protecting. Fixes: Coverity CID 1460207 Signed-off-by: Peter Maydell<[email protected]> --- v1->v2: use assert() rather than just deleting the if()s
Reviewed-by: Richard Henderson <[email protected]> r~
