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src/share/vm/opto/callGenerator.hpp@7c57aead6d3e (annotated)

src/share/vm/opto/callGenerator.hpp

Thu, 12 Nov 2009 09:24:21 -0800

author

never

date

Thu, 12 Nov 2009 09:24:21 -0800

changeset 1515

7c57aead6d3e

parent 435

a61af66fc99e

child 1572

97125851f396

permissions

-rw-r--r--

6892658: C2 should optimize some stringbuilder patterns
Reviewed-by: kvn, twisti

duke@435	1	/*
duke@435	2	* Copyright 2000-2005 Sun Microsystems, Inc. All Rights Reserved.
duke@435	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435	4	*
duke@435	5	* This code is free software; you can redistribute it and/or modify it
duke@435	6	* under the terms of the GNU General Public License version 2 only, as
duke@435	7	* published by the Free Software Foundation.
duke@435	8	*
duke@435	9	* This code is distributed in the hope that it will be useful, but WITHOUT
duke@435	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@435	12	* version 2 for more details (a copy is included in the LICENSE file that
duke@435	13	* accompanied this code).
duke@435	14	*
duke@435	15	* You should have received a copy of the GNU General Public License version
duke@435	16	* 2 along with this work; if not, write to the Free Software Foundation,
duke@435	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435	18	*
duke@435	19	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435	20	* CA 95054 USA or visit www.sun.com if you need additional information or
duke@435	21	* have any questions.
duke@435	22	*
duke@435	23	*/
duke@435	24
duke@435	25	//---------------------------CallGenerator-------------------------------------
duke@435	26	// The subclasses of this class handle generation of ideal nodes for
duke@435	27	// call sites and method entry points.
duke@435	28
duke@435	29	class CallGenerator : public ResourceObj {
duke@435	30	public:
duke@435	31	enum {
duke@435	32	xxxunusedxxx
duke@435	33	};
duke@435	34
duke@435	35	private:
duke@435	36	ciMethod* _method; // The method being called.
duke@435	37
duke@435	38	protected:
duke@435	39	CallGenerator(ciMethod* method);
duke@435	40
duke@435	41	public:
duke@435	42	// Accessors
duke@435	43	ciMethod* method() const { return _method; }
duke@435	44
duke@435	45	// is_inline: At least some code implementing the method is copied here.
duke@435	46	virtual bool is_inline() const { return false; }
duke@435	47	// is_intrinsic: There's a method-specific way of generating the inline code.
duke@435	48	virtual bool is_intrinsic() const { return false; }
duke@435	49	// is_parse: Bytecodes implementing the specific method are copied here.
duke@435	50	virtual bool is_parse() const { return false; }
duke@435	51	// is_virtual: The call uses the receiver type to select or check the method.
duke@435	52	virtual bool is_virtual() const { return false; }
duke@435	53	// is_deferred: The decision whether to inline or not is deferred.
duke@435	54	virtual bool is_deferred() const { return false; }
duke@435	55	// is_predicted: Uses an explicit check against a predicted type.
duke@435	56	virtual bool is_predicted() const { return false; }
duke@435	57	// is_trap: Does not return to the caller. (E.g., uncommon trap.)
duke@435	58	virtual bool is_trap() const { return false; }
duke@435	59
never@1515	60	// is_late_inline: supports conversion of call into an inline
never@1515	61	virtual bool is_late_inline() const { return false; }
never@1515	62	// Replace the call with an inline version of the code
never@1515	63	virtual void do_late_inline() { ShouldNotReachHere(); }
never@1515	64
never@1515	65	virtual CallStaticJavaNode* call_node() const { ShouldNotReachHere(); return NULL; }
never@1515	66
duke@435	67	// Note: It is possible for a CG to be both inline and virtual.
duke@435	68	// (The hashCode intrinsic does a vtable check and an inlined fast path.)
duke@435	69
duke@435	70	// Utilities:
duke@435	71	const TypeFunc* tf() const;
duke@435	72
duke@435	73	// The given jvms has state and arguments for a call to my method.
duke@435	74	// Edges after jvms->argoff() carry all (pre-popped) argument values.
duke@435	75	//
duke@435	76	// Update the map with state and return values (if any) and return it.
duke@435	77	// The return values (0, 1, or 2) must be pushed on the map's stack,
duke@435	78	// and the sp of the jvms incremented accordingly.
duke@435	79	//
duke@435	80	// The jvms is returned on success. Alternatively, a copy of the
duke@435	81	// given jvms, suitably updated, may be returned, in which case the
duke@435	82	// caller should discard the original jvms.
duke@435	83	//
duke@435	84	// The non-Parm edges of the returned map will contain updated global state,
duke@435	85	// and one or two edges before jvms->sp() will carry any return values.
duke@435	86	// Other map edges may contain locals or monitors, and should not
duke@435	87	// be changed in meaning.
duke@435	88	//
duke@435	89	// If the call traps, the returned map must have a control edge of top.
duke@435	90	// If the call can throw, the returned map must report has_exceptions().
duke@435	91	//
duke@435	92	// If the result is NULL, it means that this CallGenerator was unable
duke@435	93	// to handle the given call, and another CallGenerator should be consulted.
duke@435	94	virtual JVMState* generate(JVMState* jvms) = 0;
duke@435	95
duke@435	96	// How to generate a call site that is inlined:
duke@435	97	static CallGenerator* for_inline(ciMethod* m, float expected_uses = -1);
duke@435	98	// How to generate code for an on-stack replacement handler.
duke@435	99	static CallGenerator* for_osr(ciMethod* m, int osr_bci);
duke@435	100
duke@435	101	// How to generate vanilla out-of-line call sites:
never@1515	102	static CallGenerator* for_direct_call(ciMethod* m, bool separate_io_projs = false); // static, special
duke@435	103	static CallGenerator* for_virtual_call(ciMethod* m, int vtable_index); // virtual, interface
duke@435	104
never@1515	105	// How to generate a replace a direct call with an inline version
never@1515	106	static CallGenerator* for_late_inline(ciMethod* m, CallGenerator* inline_cg);
never@1515	107
duke@435	108	// How to make a call but defer the decision whether to inline or not.
duke@435	109	static CallGenerator* for_warm_call(WarmCallInfo* ci,
duke@435	110	CallGenerator* if_cold,
duke@435	111	CallGenerator* if_hot);
duke@435	112
duke@435	113	// How to make a call that optimistically assumes a receiver type:
duke@435	114	static CallGenerator* for_predicted_call(ciKlass* predicted_receiver,
duke@435	115	CallGenerator* if_missed,
duke@435	116	CallGenerator* if_hit,
duke@435	117	float hit_prob);
duke@435	118
duke@435	119	// How to make a call that gives up and goes back to the interpreter:
duke@435	120	static CallGenerator* for_uncommon_trap(ciMethod* m,
duke@435	121	Deoptimization::DeoptReason reason,
duke@435	122	Deoptimization::DeoptAction action);
duke@435	123
duke@435	124	// Registry for intrinsics:
duke@435	125	static CallGenerator* for_intrinsic(ciMethod* m);
duke@435	126	static void register_intrinsic(ciMethod* m, CallGenerator* cg);
duke@435	127	};
duke@435	128
duke@435	129	class InlineCallGenerator : public CallGenerator {
duke@435	130	virtual bool is_inline() const { return true; }
duke@435	131
duke@435	132	protected:
duke@435	133	InlineCallGenerator(ciMethod* method) : CallGenerator(method) { }
duke@435	134	};
duke@435	135
duke@435	136
duke@435	137	//---------------------------WarmCallInfo--------------------------------------
duke@435	138	// A struct to collect information about a given call site.
duke@435	139	// Helps sort call sites into "hot", "medium", and "cold".
duke@435	140	// Participates in the queueing of "medium" call sites for possible inlining.
duke@435	141	class WarmCallInfo : public ResourceObj {
duke@435	142	private:
duke@435	143
duke@435	144	CallNode* _call; // The CallNode which may be inlined.
duke@435	145	CallGenerator* _hot_cg;// CG for expanding the call node
duke@435	146
duke@435	147	// These are the metrics we use to evaluate call sites:
duke@435	148
duke@435	149	float _count; // How often do we expect to reach this site?
duke@435	150	float _profit; // How much time do we expect to save by inlining?
duke@435	151	float _work; // How long do we expect the average call to take?
duke@435	152	float _size; // How big do we expect the inlined code to be?
duke@435	153
duke@435	154	float _heat; // Combined score inducing total order on call sites.
duke@435	155	WarmCallInfo* _next; // Next cooler call info in pending queue.
duke@435	156
duke@435	157	// Count is the number of times this call site is expected to be executed.
duke@435	158	// Large count is favorable for inlining, because the extra compilation
duke@435	159	// work will be amortized more completely.
duke@435	160
duke@435	161	// Profit is a rough measure of the amount of time we expect to save
duke@435	162	// per execution of this site if we inline it. (1.0 == call overhead)
duke@435	163	// Large profit favors inlining. Negative profit disables inlining.
duke@435	164
duke@435	165	// Work is a rough measure of the amount of time a typical out-of-line
duke@435	166	// call from this site is expected to take. (1.0 == call, no-op, return)
duke@435	167	// Small work is somewhat favorable for inlining, since methods with
duke@435	168	// short "hot" traces are more likely to inline smoothly.
duke@435	169
duke@435	170	// Size is the number of graph nodes we expect this method to produce,
duke@435	171	// not counting the inlining of any further warm calls it may include.
duke@435	172	// Small size favors inlining, since small methods are more likely to
duke@435	173	// inline smoothly. The size is estimated by examining the native code
duke@435	174	// if available. The method bytecodes are also examined, assuming
duke@435	175	// empirically observed node counts for each kind of bytecode.
duke@435	176
duke@435	177	// Heat is the combined "goodness" of a site's inlining. If we were
duke@435	178	// omniscient, it would be the difference of two sums of future execution
duke@435	179	// times of code emitted for this site (amortized across multiple sites if
duke@435	180	// sharing applies). The two sums are for versions of this call site with
duke@435	181	// and without inlining.
duke@435	182
duke@435	183	// We approximate this mythical quantity by playing with averages,
duke@435	184	// rough estimates, and assumptions that history repeats itself.
duke@435	185	// The basic formula count * profit is heuristically adjusted
duke@435	186	// by looking at the expected compilation and execution times of
duke@435	187	// of the inlined call.
duke@435	188
duke@435	189	// Note: Some of these metrics may not be present in the final product,
duke@435	190	// but exist in development builds to experiment with inline policy tuning.
duke@435	191
duke@435	192	// This heuristic framework does not model well the very significant
duke@435	193	// effects of multiple-level inlining. It is possible to see no immediate
duke@435	194	// profit from inlining X->Y, but to get great profit from a subsequent
duke@435	195	// inlining X->Y->Z.
duke@435	196
duke@435	197	// This framework does not take well into account the problem of N**2 code
duke@435	198	// size in a clique of mutually inlinable methods.
duke@435	199
duke@435	200	WarmCallInfo* next() const { return _next; }
duke@435	201	void set_next(WarmCallInfo* n) { _next = n; }
duke@435	202
duke@435	203	static WarmCallInfo* _always_hot;
duke@435	204	static WarmCallInfo* _always_cold;
duke@435	205
duke@435	206	public:
duke@435	207	// Because WarmInfo objects live over the entire lifetime of the
duke@435	208	// Compile object, they are allocated into the comp_arena, which
duke@435	209	// does not get resource marked or reset during the compile process
duke@435	210	void *operator new( size_t x, Compile* C ) { return C->comp_arena()->Amalloc(x); }
duke@435	211	void operator delete( void * ) { } // fast deallocation
duke@435	212
duke@435	213	static WarmCallInfo* always_hot();
duke@435	214	static WarmCallInfo* always_cold();
duke@435	215
duke@435	216	WarmCallInfo() {
duke@435	217	_call = NULL;
duke@435	218	_hot_cg = NULL;
duke@435	219	_next = NULL;
duke@435	220	_count = _profit = _work = _size = _heat = 0;
duke@435	221	}
duke@435	222
duke@435	223	CallNode* call() const { return _call; }
duke@435	224	float count() const { return _count; }
duke@435	225	float size() const { return _size; }
duke@435	226	float work() const { return _work; }
duke@435	227	float profit() const { return _profit; }
duke@435	228	float heat() const { return _heat; }
duke@435	229
duke@435	230	void set_count(float x) { _count = x; }
duke@435	231	void set_size(float x) { _size = x; }
duke@435	232	void set_work(float x) { _work = x; }
duke@435	233	void set_profit(float x) { _profit = x; }
duke@435	234	void set_heat(float x) { _heat = x; }
duke@435	235
duke@435	236	// Load initial heuristics from profiles, etc.
duke@435	237	// The heuristics can be tweaked further by the caller.
duke@435	238	void init(JVMState* call_site, ciMethod* call_method, ciCallProfile& profile, float prof_factor);
duke@435	239
duke@435	240	static float MAX_VALUE() { return +1.0e10; }
duke@435	241	static float MIN_VALUE() { return -1.0e10; }
duke@435	242
duke@435	243	float compute_heat() const;
duke@435	244
duke@435	245	void set_call(CallNode* call) { _call = call; }
duke@435	246	void set_hot_cg(CallGenerator* cg) { _hot_cg = cg; }
duke@435	247
duke@435	248	// Do not queue very hot or very cold calls.
duke@435	249	// Make very cold ones out of line immediately.
duke@435	250	// Inline very hot ones immediately.
duke@435	251	// These queries apply various tunable limits
duke@435	252	// to the above metrics in a systematic way.
duke@435	253	// Test for coldness before testing for hotness.
duke@435	254	bool is_cold() const;
duke@435	255	bool is_hot() const;
duke@435	256
duke@435	257	// Force a warm call to be hot. This worklists the call node for inlining.
duke@435	258	void make_hot();
duke@435	259
duke@435	260	// Force a warm call to be cold. This worklists the call node for out-of-lining.
duke@435	261	void make_cold();
duke@435	262
duke@435	263	// A reproducible total ordering, in which heat is the major key.
duke@435	264	bool warmer_than(WarmCallInfo* that);
duke@435	265
duke@435	266	// List management. These methods are called with the list head,
duke@435	267	// and return the new list head, inserting or removing the receiver.
duke@435	268	WarmCallInfo* insert_into(WarmCallInfo* head);
duke@435	269	WarmCallInfo* remove_from(WarmCallInfo* head);
duke@435	270
duke@435	271	#ifndef PRODUCT
duke@435	272	void print() const;
duke@435	273	void print_all() const;
duke@435	274	int count_all() const;
duke@435	275	#endif
duke@435	276	};