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Deoptimize JSOP_TABLESWITCH to JSOP_LOOKUPSWITCH upon first duplicate case label (74474, r=rogerl, sr=shaver).

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git-svn-id: svn://10.0.0.236/trunk@94187 18797224-902f-48f8-a5cc-f745e15eee43
This commit is contained in:
brendan%mozilla.org
2001-05-08 01:21:01 +00:00
parent 21763313ee
commit 7b329a191b
1 changed files with 69 additions and 15 deletions
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84
mozilla/js/src/jsemit.c
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@@ -1110,17 +1110,24 @@ js_EmitTree(JSContext *cx, JSCodeGenerator *cg, JSParseNode *pn)
pn2 = pn->pn_kid2;
ncases = pn2->pn_count;
ok = JS_TRUE;
if (ncases == 0 ||
(ncases == 1 &&
(hasDefault = (pn2->pn_head->pn_type == TOK_DEFAULT)))) {
ncases = 0;
low = 0;
high = -1;
ok = JS_TRUE;
} else {
#define INTMAP_LENGTH 256
jsbitmap intmap_space[INTMAP_LENGTH];
jsbitmap *intmap = NULL;
int32 intmap_bitlen = 0;
low = JSVAL_INT_MAX;
high = JSVAL_INT_MIN;
cg2.current = NULL;
mark = JS_ARENA_MARK(&cx->tempPool);
for (pn3 = pn2->pn_head; pn3; pn3 = pn3->pn_next) {
if (pn3->pn_type == TOK_DEFAULT) {
hasDefault = JS_TRUE;
@@ -1139,8 +1146,10 @@ js_EmitTree(JSContext *cx, JSCodeGenerator *cg, JSParseNode *pn)
pn3->pn_val = INT_TO_JSVAL(i);
} else {
atom = js_AtomizeDouble(cx, d, 0);
if (!atom)
return JS_FALSE;
if (!atom) {
ok = JS_FALSE;
goto release;
}
pn3->pn_val = ATOM_KEY(atom);
}
break;
@@ -1163,24 +1172,29 @@ js_EmitTree(JSContext *cx, JSCodeGenerator *cg, JSParseNode *pn)
}
} else {
/* Pre-ECMAv2 switch evals case exprs at compile time. */
if (!js_InitCodeGenerator(cx, &cg2, cg->filename,
ok = js_InitCodeGenerator(cx, &cg2, cg->filename,
pn3->pn_pos.begin.lineno,
cg->principals)) {
return JS_FALSE;
}
cg->principals);
if (!ok)
goto release;
cg2.currentLine = pn4->pn_pos.begin.lineno;
if (!js_EmitTree(cx, &cg2, pn4))
return JS_FALSE;
if (js_Emit1(cx, &cg2, JSOP_POPV) < 0)
return JS_FALSE;
ok = js_EmitTree(cx, &cg2, pn4);
if (!ok)
goto release;
if (js_Emit1(cx, &cg2, JSOP_POPV) < 0) {
ok = JS_FALSE;
goto release;
}
script = js_NewScriptFromCG(cx, &cg2, NULL);
if (!script)
return JS_FALSE;
if (!script) {
ok = JS_FALSE;
goto release;
}
ok = js_Execute(cx, cx->fp->scopeChain, script, cx->fp, 0,
&pn3->pn_val);
js_DestroyScript(cx, script);
if (!ok)
return JS_FALSE;
goto release;
}
if (!JSVAL_IS_NUMBER(pn3->pn_val) &&
@@ -1189,7 +1203,8 @@ js_EmitTree(JSContext *cx, JSCodeGenerator *cg, JSParseNode *pn)
cg->currentLine = pn3->pn_pos.begin.lineno;
js_ReportCompileErrorNumber(cx, NULL, cg, JSREPORT_ERROR,
JSMSG_BAD_CASE);
return JS_FALSE;
ok = JS_FALSE;
goto release;
}
if (switchop != JSOP_TABLESWITCH)
@@ -1207,7 +1222,46 @@ js_EmitTree(JSContext *cx, JSCodeGenerator *cg, JSParseNode *pn)
low = i;
if (high < i)
high = i;
/*
* Check for duplicates, which require a JSOP_LOOKUPSWITCH.
* We bias i by 32768 if it's negative, and hope that's a rare
* case (because it requires a malloc'd bitmap).
*/
if (i < 0)
i += JS_BIT(15);
if (i >= intmap_bitlen) {
if (!intmap) {
intmap = intmap_space;
intmap_bitlen = INTMAP_LENGTH << JS_BITS_PER_WORD_LOG2;
} else {
/* Just grab 8K for the worst-case bitmap. */
intmap_bitlen = JS_BIT(16);
JS_ARENA_ALLOCATE_CAST(intmap, jsbitmap *,
&cx->tempPool,
(JS_BIT(16) >>
JS_BITS_PER_WORD_LOG2)
* sizeof(jsbitmap));
if (!intmap) {
JS_ReportOutOfMemory(cx);
ok = JS_FALSE;
goto release;
}
}
memset(intmap, 0, intmap_bitlen >> JS_BITS_PER_BYTE_LOG2);
}
if (JS_TEST_BIT(intmap, i)) {
switchop = JSOP_LOOKUPSWITCH;
continue;
}
JS_SET_BIT(intmap, i);
}
release:
JS_ARENA_RELEASE(&cx->tempPool, mark);
if (!ok)
return JS_FALSE;
if (switchop == JSOP_CONDSWITCH) {
JS_ASSERT(!cg2.current);
} else {