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conditional jumps "deunified"

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(if a jump table is used, the unification may harm jump prediction.)
This commit is contained in:
Roberto Ierusalimschy
2018-02-21 16:43:44 -03:00
parent b03dddf9e4
commit c72ac048b9
1 changed files with 28 additions and 15 deletions
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43
lvm.c
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@@ -1,5 +1,5 @@
/* /*
** $Id: lvm.c,v 2.344 2018/02/21 13:47:03 roberto Exp roberto $ ** $Id: lvm.c,v 2.345 2018/02/21 15:49:32 roberto Exp roberto $
** Lua virtual machine ** Lua virtual machine
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@@ -804,6 +804,14 @@ void luaV_finishOp (lua_State *L) {
/* for test instructions, execute the jump instruction that follows it */ /* for test instructions, execute the jump instruction that follows it */
#define donextjump(ci) { i = *pc; dojump(ci, i, 1); } #define donextjump(ci) { i = *pc; dojump(ci, i, 1); }
/*
** do a conditional jump: skip next instruction if 'cond' is not what
** was expected (parameter 'k'), else do next instruction, which must
** be a jump.
*/
#define docondjump() if (cond != GETARG_k(i)) pc++; else donextjump(ci);
/* /*
** Correct global 'pc'. ** Correct global 'pc'.
*/ */
@@ -1428,7 +1436,8 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmcase(OP_EQ) { vmcase(OP_EQ) {
TValue *rb = vRB(i); TValue *rb = vRB(i);
Protect(cond = luaV_equalobj(L, vra, rb)); Protect(cond = luaV_equalobj(L, vra, rb));
goto condjump; docondjump();
vmbreak;
} }
vmcase(OP_LT) { vmcase(OP_LT) {
TValue *rb = vRB(i); TValue *rb = vRB(i);
@@ -1438,7 +1447,8 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
cond = LTnum(vra, rb); cond = LTnum(vra, rb);
else else
Protect(cond = lessthanothers(L, vra, rb)); Protect(cond = lessthanothers(L, vra, rb));
goto condjump; docondjump();
vmbreak;
} }
vmcase(OP_LE) { vmcase(OP_LE) {
TValue *rb = vRB(i); TValue *rb = vRB(i);
@@ -1448,13 +1458,15 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
cond = LEnum(vra, rb); cond = LEnum(vra, rb);
else else
Protect(cond = lessequalothers(L, vra, rb)); Protect(cond = lessequalothers(L, vra, rb));
goto condjump; docondjump();
vmbreak;
} }
vmcase(OP_EQK) { vmcase(OP_EQK) {
TValue *rb = KB(i); TValue *rb = KB(i);
/* basic types do not use '__eq'; we can use raw equality */ /* basic types do not use '__eq'; we can use raw equality */
cond = luaV_equalobj(NULL, vra, rb); cond = luaV_equalobj(NULL, vra, rb);
goto condjump; docondjump();
vmbreak;
} }
vmcase(OP_EQI) { vmcase(OP_EQI) {
int im = GETARG_sB(i); int im = GETARG_sB(i);
@@ -1464,7 +1476,8 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
cond = luai_numeq(fltvalue(vra), cast_num(im)); cond = luai_numeq(fltvalue(vra), cast_num(im));
else else
cond = 0; /* other types cannot be equal to a number */ cond = 0; /* other types cannot be equal to a number */
goto condjump; docondjump();
vmbreak;
} }
vmcase(OP_LTI) { vmcase(OP_LTI) {
int im = GETARG_sB(i); int im = GETARG_sB(i);
@@ -1474,7 +1487,8 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
cond = luai_numlt(fltvalue(vra), cast_num(im)); cond = luai_numlt(fltvalue(vra), cast_num(im));
else else
Protect(cond = luaT_callorderiTM(L, vra, im, 0, TM_LT)); Protect(cond = luaT_callorderiTM(L, vra, im, 0, TM_LT));
goto condjump; docondjump();
vmbreak;
} }
vmcase(OP_LEI) { vmcase(OP_LEI) {
int im = GETARG_sB(i); int im = GETARG_sB(i);
@@ -1484,7 +1498,8 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
cond = luai_numle(fltvalue(vra), cast_num(im)); cond = luai_numle(fltvalue(vra), cast_num(im));
else else
Protect(cond = luaT_callorderiTM(L, vra, im, 0, TM_LE)); Protect(cond = luaT_callorderiTM(L, vra, im, 0, TM_LE));
goto condjump; docondjump();
vmbreak;
} }
vmcase(OP_GTI) { vmcase(OP_GTI) {
int im = GETARG_sB(i); int im = GETARG_sB(i);
@@ -1494,7 +1509,8 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
cond = luai_numlt(cast_num(im), fltvalue(vra)); cond = luai_numlt(cast_num(im), fltvalue(vra));
else else
Protect(cond = luaT_callorderiTM(L, vra, im, 1, TM_LT)); Protect(cond = luaT_callorderiTM(L, vra, im, 1, TM_LT));
goto condjump; docondjump();
vmbreak;
} }
vmcase(OP_GEI) { vmcase(OP_GEI) {
int im = GETARG_sB(i); int im = GETARG_sB(i);
@@ -1504,15 +1520,12 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
cond = luai_numle(cast_num(im), fltvalue(vra)); cond = luai_numle(cast_num(im), fltvalue(vra));
else else
Protect(cond = luaT_callorderiTM(L, vra, im, 1, TM_LE)); Protect(cond = luaT_callorderiTM(L, vra, im, 1, TM_LE));
goto condjump; docondjump();
vmbreak;
} }
vmcase(OP_TEST) { vmcase(OP_TEST) {
cond = !l_isfalse(vra); cond = !l_isfalse(vra);
condjump: docondjump();
if (cond != GETARG_k(i))
pc++; /* skip next jump */
else
donextjump(ci);
vmbreak; vmbreak;
} }
vmcase(OP_TESTSET) { vmcase(OP_TESTSET) {