diff options
Diffstat (limited to 'target-i386')
| -rw-r--r-- | target-i386/translate.c | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/target-i386/translate.c b/target-i386/translate.c index 782f7d2666..6243e36661 100644 --- a/target-i386/translate.c +++ b/target-i386/translate.c @@ -115,6 +115,7 @@ typedef struct DisasContext { int tf; /* TF cpu flag */ int singlestep_enabled; /* "hardware" single step enabled */ int jmp_opt; /* use direct block chaining for direct jumps */ + int repz_opt; /* optimize jumps within repz instructions */ int mem_index; /* select memory access functions */ uint64_t flags; /* all execution flags */ struct TranslationBlock *tb; @@ -1215,7 +1216,7 @@ static inline void gen_repz_ ## op(DisasContext *s, TCGMemOp ot, \ gen_op_add_reg_im(s->aflag, R_ECX, -1); \ /* a loop would cause two single step exceptions if ECX = 1 \ before rep string_insn */ \ - if (!s->jmp_opt) \ + if (s->repz_opt) \ gen_op_jz_ecx(s->aflag, l2); \ gen_jmp(s, cur_eip); \ } @@ -1233,7 +1234,7 @@ static inline void gen_repz_ ## op(DisasContext *s, TCGMemOp ot, \ gen_op_add_reg_im(s->aflag, R_ECX, -1); \ gen_update_cc_op(s); \ gen_jcc1(s, (JCC_Z << 1) | (nz ^ 1), l2); \ - if (!s->jmp_opt) \ + if (s->repz_opt) \ gen_op_jz_ecx(s->aflag, l2); \ gen_jmp(s, cur_eip); \ } @@ -7951,6 +7952,17 @@ static inline void gen_intermediate_code_internal(X86CPU *cpu, || (flags & HF_SOFTMMU_MASK) #endif ); + /* Do not optimize repz jumps at all in icount mode, because + rep movsS instructions are execured with different paths + in !repz_opt and repz_opt modes. The first one was used + always except single step mode. And this setting + disables jumps optimization and control paths become + equivalent in run and single step modes. + Now there will be no jump optimization for repz in + record/replay modes and there will always be an + additional step for ecx=0 when icount is enabled. + */ + dc->repz_opt = !dc->jmp_opt && !use_icount; #if 0 /* check addseg logic */ if (!dc->addseg && (dc->vm86 || !dc->pe || !dc->code32)) |