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No longer used hacked liveness_pass_1

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This hack was introduced in issue#287 which later becomes endless maintainance pain.

=====

Our previous check_exit_request use `brcond` in the middle of a TranslationBlock which

breaks the assumptions and thus a hack to liveness_pass_1 is used for _all_ brcond instructions

which causes issues for MIPS and many other scenarios.

=====

This patch also resolves PC not sync-ed when no memory hooks are installed, finally. Now

Unicorn will always have correct PC no matter what happens.
This commit is contained in:
mio
2025-04-12 21:38:14 +08:00
parent e89eb87d04
commit 7f48b1dd4a
28 changed files with 80 additions and 63 deletions
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20
qemu/tcg/tcg-op.c
View File

@@ -2852,8 +2852,6 @@ static void gen_ldst_i64(TCGContext *tcg_ctx, TCGOpcode opc, TCGv_i64 val, TCGv
// if so, we jump to the block epilogue to quit immediately.
void check_exit_request(TCGContext *tcg_ctx)
{
TCGv_i32 count;
// Unicorn:
// For ARM IT block, we couldn't exit in the middle of the
// block and this is the our hack here.
@@ -2861,23 +2859,17 @@ void check_exit_request(TCGContext *tcg_ctx)
return;
}
count = tcg_temp_new_i32(tcg_ctx);
tcg_gen_ld_i32(tcg_ctx, count, tcg_ctx->cpu_env,
offsetof(ArchCPU, neg.icount_decr.u32) -
offsetof(ArchCPU, env));
TCGv_ptr puc = tcg_const_ptr(tcg_ctx, tcg_ctx->uc);
TCGv_i32 tmp = tcg_const_i32(tcg_ctx, 0);
// Unicorn:
// We CANT'T use brcondi_i32 here or we will fail liveness analysis
// because it marks the end of BB
if (tcg_ctx->delay_slot_flag != NULL) {
TCGv_i32 tmp = tcg_const_i32(tcg_ctx, 0);
// dest = (c1 cond c2 ? v1 : v2)
tcg_gen_movcond_i32(tcg_ctx, TCG_COND_GT, count, tcg_ctx->delay_slot_flag, tmp, tcg_ctx->delay_slot_flag, count);
tcg_temp_free_i32(tcg_ctx, tmp);
tcg_gen_mov_i32(tcg_ctx, tmp, tcg_ctx->delay_slot_flag);
}
tcg_gen_brcondi_i32(tcg_ctx, TCG_COND_LT, count, 0, tcg_ctx->exitreq_label);
tcg_temp_free_i32(tcg_ctx, count);
gen_helper_check_exit_request(tcg_ctx, puc, tmp);
tcg_temp_free_i32(tcg_ctx, tmp);
tcg_temp_free_ptr(tcg_ctx, puc);
}
static void tcg_gen_req_mo(TCGContext *tcg_ctx, TCGBar type)

26
qemu/tcg/tcg.c
View File

@@ -2243,17 +2243,6 @@ static inline void la_reset_pref(TCGContext *tcg_ctx, TCGTemp *ts)
= (ts->state == TS_DEAD ? 0 : tcg_ctx->tcg_target_available_regs[ts->type]);
}
/*
Unicorn: for brcond, we should refresh liveness states for TCG globals
*/
static void la_brcond_end(TCGContext *s, int ng)
{
int i;
for (i = 0; i < ng; i++) {
s->temps[i].state |= TS_MEM;
}
}
/* liveness analysis: end of function: all temps are dead, and globals
should be in memory. */
@@ -2581,20 +2570,7 @@ static void liveness_pass_1(TCGContext *s)
if (def->flags & TCG_OPF_BB_EXIT) {
la_func_end(s, nb_globals, nb_temps);
} else if (def->flags & TCG_OPF_BB_END) {
// Unicorn: do not optimize dead temps on brcond,
// this causes problem because check_exit_request() inserts
// brcond instruction in the middle of the TB,
// which incorrectly flags end-of-block
if (opc != INDEX_op_brcond_i32) {
la_bb_end(s, nb_globals, nb_temps);
} else {
// Unicorn: we do not touch dead temps for brcond,
// but we should refresh TCG globals In-Memory states,
// otherwise, important CPU states(especially conditional flags) might be forgotten,
// result in wrongly generated host code that run into wrong branch.
// Refer to https://github.com/unicorn-engine/unicorn/issues/287 for further information
la_brcond_end(s, nb_globals);
}
la_bb_end(s, nb_globals, nb_temps);
} else if (def->flags & TCG_OPF_SIDE_EFFECTS) {
la_global_sync(s, nb_globals);
if (def->flags & TCG_OPF_CALL_CLOBBER) {