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Fix HREFK forwarding vs. table.clear().

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Reported by XmiliaH.
This commit is contained in:
Mike Pall 2022-01-15 17:52:21 +01:00
parent bc1bdbf620
commit d5a237eae0
1 changed files with 32 additions and 31 deletions
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63
src/lj_opt_mem.c
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@ -72,6 +72,34 @@ static AliasRet aa_table(jit_State *J, IRRef ta, IRRef tb)
return aa_escape(J, taba, tabb);
}
/* Check whether there's no aliasing table.clear. */
static int fwd_aa_tab_clear(jit_State *J, IRRef lim, IRRef ta)
{
IRRef ref = J->chain[IR_CALLS];
while (ref > lim) {
IRIns *calls = IR(ref);
if (calls->op2 == IRCALL_lj_tab_clear &&
(ta == calls->op1 || aa_table(J, ta, calls->op1) != ALIAS_NO))
return 0; /* Conflict. */
ref = calls->prev;
}
return 1; /* No conflict. Can safely FOLD/CSE. */
}
/* Check whether there's no aliasing NEWREF/table.clear for the left operand. */
int LJ_FASTCALL lj_opt_fwd_tptr(jit_State *J, IRRef lim)
{
IRRef ta = fins->op1;
IRRef ref = J->chain[IR_NEWREF];
while (ref > lim) {
IRIns *newref = IR(ref);
if (ta == newref->op1 || aa_table(J, ta, newref->op1) != ALIAS_NO)
return 0; /* Conflict. */
ref = newref->prev;
}
return fwd_aa_tab_clear(J, lim, ta);
}
/* Alias analysis for array and hash access using key-based disambiguation. */
static AliasRet aa_ahref(jit_State *J, IRIns *refa, IRIns *refb)
{
@ -154,7 +182,8 @@ static TRef fwd_ahload(jit_State *J, IRRef xref)
IRIns *ir = (xr->o == IR_HREFK || xr->o == IR_AREF) ? IR(xr->op1) : xr;
IRRef tab = ir->op1;
ir = IR(tab);
if (ir->o == IR_TNEW || (ir->o == IR_TDUP && irref_isk(xr->op2))) {
if ((ir->o == IR_TNEW || (ir->o == IR_TDUP && irref_isk(xr->op2))) &&
fwd_aa_tab_clear(J, tab, tab)) {
/* A NEWREF with a number key may end up pointing to the array part.
** But it's referenced from HSTORE and not found in the ASTORE chain.
** For now simply consider this a conflict without forwarding anything.
@ -269,7 +298,7 @@ TRef LJ_FASTCALL lj_opt_fwd_hrefk(jit_State *J)
while (ref > tab) {
IRIns *newref = IR(ref);
if (tab == newref->op1) {
if (fright->op1 == newref->op2)
if (fright->op1 == newref->op2 && fwd_aa_tab_clear(J, ref, tab))
return ref; /* Forward from NEWREF. */
else
goto docse;
@ -279,7 +308,7 @@ TRef LJ_FASTCALL lj_opt_fwd_hrefk(jit_State *J)
ref = newref->prev;
}
/* No conflicting NEWREF: key location unchanged for HREFK of TDUP. */
if (IR(tab)->o == IR_TDUP)
if (IR(tab)->o == IR_TDUP && fwd_aa_tab_clear(J, tab, tab))
fins->t.irt &= ~IRT_GUARD; /* Drop HREFK guard. */
docse:
return CSEFOLD;
@ -313,34 +342,6 @@ int LJ_FASTCALL lj_opt_fwd_href_nokey(jit_State *J)
return 1; /* No conflict. Can fold to niltv. */
}
/* Check whether there's no aliasing table.clear. */
static int fwd_aa_tab_clear(jit_State *J, IRRef lim, IRRef ta)
{
IRRef ref = J->chain[IR_CALLS];
while (ref > lim) {
IRIns *calls = IR(ref);
if (calls->op2 == IRCALL_lj_tab_clear &&
(ta == calls->op1 || aa_table(J, ta, calls->op1) != ALIAS_NO))
return 0; /* Conflict. */
ref = calls->prev;
}
return 1; /* No conflict. Can safely FOLD/CSE. */
}
/* Check whether there's no aliasing NEWREF/table.clear for the left operand. */
int LJ_FASTCALL lj_opt_fwd_tptr(jit_State *J, IRRef lim)
{
IRRef ta = fins->op1;
IRRef ref = J->chain[IR_NEWREF];
while (ref > lim) {
IRIns *newref = IR(ref);
if (ta == newref->op1 || aa_table(J, ta, newref->op1) != ALIAS_NO)
return 0; /* Conflict. */
ref = newref->prev;
}
return fwd_aa_tab_clear(J, lim, ta);
}
/* ASTORE/HSTORE elimination. */
TRef LJ_FASTCALL lj_opt_dse_ahstore(jit_State *J)
{