Magic-Mirror/gecko-dev
1
0
Fork 0
mirror of https://github.com/mozilla/gecko-dev.git synced 2024-12-02 10:00:54 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Optimize lightweight function calls, and bound their recursion (27767, r=rogerl@netscape.com).

Browse Source
This commit is contained in:
brendan%mozilla.org 2000-03-23 23:29:36 +00:00
parent 0376d3f7af
commit 17eca8e2c8
2 changed files with 280 additions and 101 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

374
js/src/jsinterp.c
View File

@ -107,7 +107,7 @@ js_FlushPropertyCacheByProp(JSContext *cx, JSProperty *prop)
/*
* Class for for/in loop property iterator objects.
*/
#define JSSLOT_ITER_STATE (JSSLOT_START)
#define JSSLOT_ITER_STATE (JSSLOT_START)
static void
prop_iterator_finalize(JSContext *cx, JSObject *obj)
@ -411,6 +411,65 @@ js_SetLocalVariable(JSContext *cx, JSObject *obj, jsval id, jsval *vp)
return JS_TRUE;
}
/*
* Compute the 'this' parameter and store it in frame as frame.thisp.
* Activation objects ("Call" objects not created with "new Call()", i.e.,
* "Call" objects that have private data) may not be referred to by 'this',
* as dictated by ECMA.
*
* N.B.: fp->argv must be set, and fp->argv[-2] must be the callee object
* reference, usually a function object. Also, fp->constructing must be
* set if we are preparing for a constructor call.
*/
static JSBool
ComputeThis(JSContext *cx, JSObject *thisp, JSStackFrame *fp)
{
JSObject *parent;
if (thisp &&
!(OBJ_GET_CLASS(cx, thisp) == &js_CallClass &&
JS_GetPrivate(cx, thisp) != NULL))
{
/* Some objects (e.g., With) delegate 'this' to another object. */
thisp = OBJ_THIS_OBJECT(cx, thisp);
if (!thisp)
return JS_FALSE;
/* Default return value for a constructor is the new object. */
if (fp->constructing)
fp->rval = OBJECT_TO_JSVAL(thisp);
} else {
/*
* ECMA requires "the global object", but in the presence of multiple
* top-level objects (windows, frames, or certain layers in the client
* object model), we prefer fun's parent. An example that causes this
* code to run:
*
* // in window w1
* function f() { return this }
* function g() { return f }
*
* // in window w2
* var h = w1.g()
* alert(h() == w1)
*
* The alert should display "true".
*/
JS_ASSERT(!fp->constructing);
parent = OBJ_GET_PARENT(cx, JSVAL_TO_OBJECT(fp->argv[-2]));
if (!parent) {
thisp = cx->globalObject;
} else {
/* walk up to find the top-level object */
thisp = parent;
while ((parent = OBJ_GET_PARENT(cx, thisp)) != NULL)
thisp = parent;
}
}
fp->thisp = thisp;
return JS_TRUE;
}
/*
* Find a function reference and its 'this' object implicit first parameter
* under argc arguments on cx's stack, and call the function. Push missing
@ -477,16 +536,16 @@ js_Invoke(JSContext *cx, uintN argc, uintN flags)
ok = clasp->convert(cx, funobj, JSTYPE_FUNCTION, &v);
if (!ok)
goto out2;
}
if (JSVAL_IS_FUNCTION(cx, v)) {
funobj = JSVAL_TO_OBJECT(v);
parent = OBJ_GET_PARENT(cx, funobj);
fun = (JSFunction *) JS_GetPrivate(cx, funobj);
if (JSVAL_IS_FUNCTION(cx, v)) {
funobj = JSVAL_TO_OBJECT(v);
parent = OBJ_GET_PARENT(cx, funobj);
fun = (JSFunction *) JS_GetPrivate(cx, funobj);
/* Make vp refer to funobj to keep it available as argv[-2]. */
*vp = v;
goto have_fun;
/* Make vp refer to funobj to keep it available as argv[-2]. */
*vp = v;
goto have_fun;
}
}
fun = NULL;
script = NULL;
@ -530,55 +589,10 @@ have_fun:
frame.special = 0;
frame.dormantNext = NULL;
/*
* Compute the 'this' parameter and store it in frame as frame.thisp.
* Activation objects ("Call" objects not created with "new Call", i.e.,
* "Call" objects with private data) may not be referred to by 'this'
* as dictated by ECMA.
*/
if (thisp &&
!(OBJ_GET_CLASS(cx, thisp) == &js_CallClass &&
JS_GetPrivate(cx, thisp) != NULL))
{
/* Some objects (e.g., With) delegate 'this' to another object. */
thisp = OBJ_THIS_OBJECT(cx, thisp);
if (!thisp) {
ok = JS_FALSE;
goto out2;
}
/* Default return value for a constructor is the new object. */
if (frame.constructing)
frame.rval = OBJECT_TO_JSVAL(thisp);
} else {
/*
* ECMA requires "the global object", but in the presence of multiple
* top-level objects (windows, frames, or certain layers in the client
* object model), we prefer fun's parent. An example that causes this
* code to run:
*
* // in window w1
* function f() { return this }
* function g() { return f }
*
* // in window w2
* var h = w1.g()
* alert(h() == w1)
*
* The alert should display "true".
*/
JS_ASSERT(!frame.constructing);
if (!parent) {
thisp = cx->globalObject;
} else {
/* walk up to find the top-level object */
JSObject *tmp;
thisp = parent;
while ((tmp = OBJ_GET_PARENT(cx, thisp)) != NULL)
thisp = tmp;
}
}
frame.thisp = thisp;
/* Compute the 'this' parameter and store it in frame as frame.thisp. */
ok = ComputeThis(cx, thisp, &frame);
if (!ok)
goto out2;
/* From here on, control must flow through label out: to return. */
cx->fp = &frame;
@ -813,16 +827,16 @@ js_Execute(JSContext *cx, JSObject *chain, JSScript *script, JSFunction *fun,
/*
* Here we wrap the call to js_Interpret with code to (conditionally)
* save and restore the old stack frame chain into a chain of 'dormant'
* frame chains. Since we are replacing cx->fp we were running into the
* problem that if gc was called, then some of the objects associated
* with the old frame chain (stored here in the C stack as 'oldfp') were
* not rooted and were being collected. This was bad. So, now we
* preserve the links to these 'dormant' frame chains in cx before
* calling js_Interpret and cleanup afterwards. gc walks these dormant
* chains and marks objects in the same way that it marks object in the
* primary cx->fp chain.
* frame chains. Since we are replacing cx->fp, we were running into
* the problem that if GC was called under this frame, some of the GC
* things associated with the old frame chain (available here only in
* the C variable 'oldfp') were not rooted and were being collected.
*
* So, now we preserve the links to these 'dormant' frame chains in cx
* before calling js_Interpret and cleanup afterwards. The GC walks
* these dormant chains and marks objects in the same way that it marks
* objects in the primary cx->fp chain.
*/
if (oldfp && oldfp != down) {
JS_ASSERT(!oldfp->dormantNext);
oldfp->dormantNext = cx->dormantFrameChain;
@ -999,17 +1013,20 @@ CheckRedeclaration(JSContext *cx, JSObject *obj, JSObject *obj2, jsid id,
#define MAX_INTERP_LEVEL 30
#endif
#define MAX_INLINE_CALL_COUNT 1000
JSBool
js_Interpret(JSContext *cx, jsval *result)
{
JSRuntime *rt;
JSStackFrame *fp;
JSScript *script;
JSVersion newvers, oldvers;
uintN inlineCallCount;
JSObject *obj, *obj2, *proto, *parent;
JSVersion currentVersion, originalVersion;
JSBranchCallback onbranch;
JSBool ok, cond;
ptrdiff_t depth, len;
jsint depth, len;
jsval *sp, *newsp;
void *mark;
jsbytecode *pc, *pc2, *endpc;
@ -1036,8 +1053,7 @@ js_Interpret(JSContext *cx, jsval *result)
FILE *tracefp;
#endif
#if JS_HAS_SWITCH_STATEMENT
jsint low, high;
uintN off, npairs;
jsint low, high, off, npairs;
JSBool match;
#endif
#if JS_HAS_GETTER_SETTER
@ -1056,20 +1072,18 @@ js_Interpret(JSContext *cx, jsval *result)
*result = JSVAL_VOID;
rt = cx->runtime;
/*
* Set registerized frame pointer and derived pointers.
*/
/* Set registerized frame pointer and derived script pointer. */
fp = cx->fp;
script = fp->script;
obj = fp->scopeChain;
/*
* Optimized Get and SetVersion for proper script language versioning.
*/
newvers = script->version;
oldvers = cx->version;
if (newvers != oldvers)
JS_SetVersion(cx, newvers);
/* Count of JS function calls that nest in this C js_Interpret frame. */
inlineCallCount = 0;
/* Optimized Get and SetVersion for proper script language versioning. */
currentVersion = script->version;
originalVersion = cx->version;
if (currentVersion != originalVersion)
JS_SetVersion(cx, currentVersion);
/*
* Prepare to call a user-supplied branch handler, and abort the script
@ -1092,19 +1106,19 @@ js_Interpret(JSContext *cx, jsval *result)
/*
* Allocate operand and pc stack slots for the script's worst-case depth.
*/
depth = (ptrdiff_t)script->depth;
depth = (jsint) script->depth;
newsp = js_AllocStack(cx, (uintN)(2 * depth), &mark);
if (!newsp) {
ok = JS_FALSE;
sp = NULL;
goto out;
}
newsp += depth;
fp->sp = sp = newsp;
sp = newsp;
SAVE_SP(fp);
while (pc < endpc) {
fp->pc = pc;
op = (JSOp)*pc;
op = (JSOp) *pc;
do_op:
cs = &js_CodeSpec[op];
len = cs->length;
@ -1205,12 +1219,65 @@ js_Interpret(JSContext *cx, jsval *result)
case JSOP_RETURN:
CHECK_BRANCH(-1);
fp->rval = POP();
if (inlineCallCount)
inline_return:
{
JSInlineFrame *ifp = (JSInlineFrame *) fp;
void *hookData = ifp->hookData;
if (hookData)
cx->runtime->callHook(cx, fp, JS_FALSE, &ok, hookData);
#if JS_HAS_ARGS_OBJECT
if (fp->argsobj)
ok &= js_PutArgsObject(cx, fp);
#endif
/* Store the return value in the caller's operand frame. */
vp = fp->argv - 2;
*vp = fp->rval;
/* Restore newsp for sanity-checking assertions about sp. */
newsp = ifp->oldsp;
/* Restore cx->fp and release the inline frame's space. */
cx->fp = fp = fp->down;
JS_ARENA_RELEASE(&cx->stackPool, ifp->mark);
/* Restore sp to point just above the return value. */
fp->sp = vp + 1;
RESTORE_SP(fp);
/* Restore the calling script's interpreter registers. */
script = fp->script;
depth = (jsint) script->depth;
pc = fp->pc;
endpc = script->code + script->length;
/* Store the generating pc for the return value. */
vp[-depth] = (jsval)pc;
/* Restore version and version control variable. */
if (script->version != currentVersion) {
currentVersion = script->version;
JS_SetVersion(cx, currentVersion);
}
/* Set remaining variables for 'goto advance_pc'. */
op = (JSOp) *pc;
cs = &js_CodeSpec[op];
len = cs->length;
/* Resume execution in the calling frame. */
inlineCallCount--;
if (ok)
goto advance_pc;
}
goto out;
#if JS_HAS_SWITCH_STATEMENT
case JSOP_DEFAULT:
(void) POP();
/* fall through */
/* FALL THROUGH */
#endif
case JSOP_GOTO:
len = GET_JUMP_OFFSET(pc);
@ -2288,7 +2355,105 @@ js_Interpret(JSContext *cx, jsval *result)
case JSOP_CALL:
case JSOP_EVAL:
argc = GET_ARGC(pc);
vp = sp - (argc + 2);
lval = *vp;
SAVE_SP(fp);
if (JSVAL_IS_FUNCTION(cx, lval) &&
(obj = JSVAL_TO_OBJECT(lval),
fun = (JSFunction *) JS_GetPrivate(cx, obj),
fun->script &&
fun->flags == 0 &&
argc >= (uintN)(fun->nargs + fun->extra)))
/* inline_call: */
{
uintN nframeslots, nvars;
jsval *oldsp;
void *mark;
JSInlineFrame *newifp;
JSInterpreterHook hook;
/* Restrict recursion of lightweight functions. */
if (inlineCallCount == MAX_INLINE_CALL_COUNT) {
JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL,
JSMSG_OVER_RECURSED);
return JS_FALSE;
}
/* Compute the number of stack slots needed for fun. */
nframeslots = (sizeof(JSInlineFrame) + sizeof(jsval) - 1)
/ sizeof(jsval);
nvars = fun->nvars;
script = fun->script;
depth = (jsint) script->depth;
/* Allocate the frame and space for vars and operands. */
oldsp = newsp;
newsp = js_AllocStack(cx, nframeslots + nvars + 2 * depth,
&mark);
if (!newsp) {
ok = JS_FALSE;
goto bad_inline_call;
}
newifp = (JSInlineFrame *) newsp;
newsp += nframeslots;
/* Initialize the stack frame. */
memset(newifp, 0, sizeof(JSInlineFrame));
newifp->frame.script = script;
newifp->frame.fun = fun;
newifp->frame.argc = argc;
newifp->frame.argv = vp + 2;
newifp->frame.rval = JSVAL_VOID;
newifp->frame.nvars = nvars;
newifp->frame.vars = newsp;
newifp->frame.down = fp;
newifp->frame.scopeChain = OBJ_GET_PARENT(cx, obj);
newifp->oldsp = oldsp;
newifp->mark = mark;
/* Compute the 'this' parameter now that argv is set. */
ok = ComputeThis(cx, JSVAL_TO_OBJECT(vp[1]), &newifp->frame);
if (!ok) {
js_FreeStack(cx, mark);
goto bad_inline_call;
}
/* Push void to initialize local variables. */
sp = newsp;
while (nvars--)
PUSH(JSVAL_VOID);
sp += depth;
newsp = sp;
SAVE_SP(&newifp->frame);
/* Call the debugger hook if present. */
hook = cx->runtime->callHook;
if (hook) {
newifp->hookData = hook(cx, &newifp->frame, JS_TRUE, 0,
cx->runtime->callHookData);
}
/* Switch to new version if necessary. */
if (script->version != currentVersion) {
currentVersion = script->version;
JS_SetVersion(cx, currentVersion);
}
/* Push the frame and set interpreter registers. */
cx->fp = fp = &newifp->frame;
pc = script->code;
endpc = pc + script->length;
inlineCallCount++;
continue;
bad_inline_call:
script = fp->script;
depth = (jsint) script->depth;
newsp = oldsp;
goto out;
}
ok = js_Invoke(cx, argc, 0);
RESTORE_SP(fp);
if (!ok)
@ -2413,15 +2578,15 @@ js_Interpret(JSContext *cx, jsval *result)
goto out;
}
pc2 += 2;
pc2 += JUMP_OFFSET_LEN;
low = GET_JUMP_OFFSET(pc2);
pc2 += 2;
pc2 += JUMP_OFFSET_LEN;
high = GET_JUMP_OFFSET(pc2);
i -= low;
if ((jsuint)i <= (jsuint)(high - low)) {
pc2 += 2 + 2 * i;
off = GET_JUMP_OFFSET(pc2);
pc2 += JUMP_OFFSET_LEN + JUMP_OFFSET_LEN * i;
off = (jsint) GET_JUMP_OFFSET(pc2);
if (off)
len = off;
}
@ -2438,9 +2603,9 @@ js_Interpret(JSContext *cx, jsval *result)
goto advance_pc;
}
pc2 += 2;
npairs = GET_ATOM_INDEX(pc2);
pc2 += 2;
pc2 += JUMP_OFFSET_LEN;
npairs = (jsint) GET_ATOM_INDEX(pc2);
pc2 += ATOM_INDEX_LEN;
#define SEARCH_PAIRS(MATCH_CODE) \
while (npairs) { \
@ -2448,11 +2613,11 @@ js_Interpret(JSContext *cx, jsval *result)
rval = ATOM_KEY(atom); \
MATCH_CODE \
if (match) { \
pc2 += 2; \
pc2 += ATOM_INDEX_LEN; \
len = GET_JUMP_OFFSET(pc2); \
goto advance_pc; \
} \
pc2 += 4; \
pc2 += ATOM_INDEX_LEN + JUMP_OFFSET_LEN; \
npairs--; \
}
if (JSVAL_IS_STRING(lval)) {
@ -3041,7 +3206,7 @@ js_Interpret(JSContext *cx, jsval *result)
#endif /* JS_HAS_INITIALIZERS */
#if JS_HAS_EXCEPTIONS
/* reset the stack to the given depth */
/* Reset the stack to the given depth. */
case JSOP_SETSP:
i = (jsint) GET_ATOM_INDEX(pc);
JS_ASSERT(i >= 0);
@ -3049,9 +3214,8 @@ js_Interpret(JSContext *cx, jsval *result)
break;
case JSOP_GOSUB:
i = PTRDIFF(pc, script->main, jsbytecode) + len;
len = GET_JUMP_OFFSET(pc);
JS_ASSERT(js_CodeSpec[JSOP_GOSUB].length == 3);
i = PTRDIFF(pc, script->main, jsbytecode) + 3;
PUSH(INT_TO_JSVAL(i));
break;
@ -3216,12 +3380,20 @@ out:
no_catch:
#endif
/*
* Check whether control fell off the end of a lightweight function, or an
* exception thrown under such a function was not caught by it. If so, go
* to the inline code under JSOP_RETURN.
*/
if (inlineCallCount)
goto inline_return;
/*
* Restore the previous frame's execution state.
*/
js_FreeStack(cx, mark);
if (newvers != oldvers)
JS_SetVersion(cx, oldvers);
if (currentVersion != originalVersion)
JS_SetVersion(cx, originalVersion);
cx->interpLevel--;
return ok;
}

7
js/src/jsinterp.h
View File

@ -71,6 +71,13 @@ struct JSStackFrame {
JSStackFrame *dormantNext; /* next dormant frame chain */
};
typedef struct JSInlineFrame {
JSStackFrame frame; /* base struct */
jsval *oldsp; /* old frame's operand stack base */
void *mark; /* mark before inline frame */
void *hookData; /* debugger call hook data */
} JSInlineFrame;
/* JS stack frame special flags. */
#define JSFRAME_DEBUGGER 0x1 /* frame for JS_EvaluateInStackFrame */
#define JSFRAME_EVAL 0x2 /* frame for obj_eval */