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js/src/jit/ValueNumbering.h@6474c204b198 (annotated)

js/src/jit/ValueNumbering.h

Wed, 31 Dec 2014 06:09:35 +0100

author

Michael Schloh von Bennewitz <michael@schloh.com>

date

Wed, 31 Dec 2014 06:09:35 +0100

changeset 0

6474c204b198

permissions

-rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

michael@0	1	/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
michael@0	2	* vim: set ts=8 sts=4 et sw=4 tw=99:
michael@0	3	* This Source Code Form is subject to the terms of the Mozilla Public
michael@0	4	* License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0	5	* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0	6
michael@0	7	#ifndef jit_ValueNumbering_h
michael@0	8	#define jit_ValueNumbering_h
michael@0	9
michael@0	10	#include "jit/MIR.h"
michael@0	11
michael@0	12	namespace js {
michael@0	13	namespace jit {
michael@0	14
michael@0	15	class ValueNumberer
michael@0	16	{
michael@0	17	protected:
michael@0	18	struct ValueHasher
michael@0	19	{
michael@0	20	typedef MDefinition * Lookup;
michael@0	21	typedef MDefinition * Key;
michael@0	22	static HashNumber hash(const Lookup &ins) {
michael@0	23	return ins->valueHash();
michael@0	24	}
michael@0	25
michael@0	26	static bool match(const Key &k, const Lookup &l) {
michael@0	27	// If one of the instructions depends on a store, and the
michael@0	28	// other instruction does not depend on the same store,
michael@0	29	// the instructions are not congruent.
michael@0	30	if (k->dependency() != l->dependency())
michael@0	31	return false;
michael@0	32	return k->congruentTo(l);
michael@0	33	}
michael@0	34	};
michael@0	35
michael@0	36	typedef HashMap<MDefinition *,
michael@0	37	uint32_t,
michael@0	38	ValueHasher,
michael@0	39	IonAllocPolicy> ValueMap;
michael@0	40
michael@0	41	struct DominatingValue
michael@0	42	{
michael@0	43	MDefinition *def;
michael@0	44	uint32_t validUntil;
michael@0	45	};
michael@0	46
michael@0	47	typedef HashMap<uint32_t,
michael@0	48	DominatingValue,
michael@0	49	DefaultHasher<uint32_t>,
michael@0	50	IonAllocPolicy> InstructionMap;
michael@0	51
michael@0	52	protected:
michael@0	53	TempAllocator &alloc() const;
michael@0	54	uint32_t lookupValue(MDefinition *ins);
michael@0	55	MDefinition *findDominatingDef(InstructionMap &defs, MDefinition *ins, size_t index);
michael@0	56
michael@0	57	MDefinition *simplify(MDefinition *def, bool useValueNumbers);
michael@0	58	MControlInstruction *simplifyControlInstruction(MControlInstruction *def);
michael@0	59	bool eliminateRedundancies();
michael@0	60
michael@0	61	bool computeValueNumbers();
michael@0	62
michael@0	63	inline bool isMarked(MDefinition *def) {
michael@0	64	return pessimisticPass_ || def->isInWorklist();
michael@0	65	}
michael@0	66
michael@0	67	void markDefinition(MDefinition *def);
michael@0	68	void unmarkDefinition(MDefinition *def);
michael@0	69
michael@0	70	void markConsumers(MDefinition *def);
michael@0	71	void markBlock(MBasicBlock *block);
michael@0	72	void setClass(MDefinition *toSet, MDefinition *representative);
michael@0	73
michael@0	74	public:
michael@0	75	static MDefinition *findSplit(MDefinition *);
michael@0	76	void breakClass(MDefinition*);
michael@0	77
michael@0	78	protected:
michael@0	79	MIRGenerator *mir;
michael@0	80	MIRGraph &graph_;
michael@0	81	ValueMap values;
michael@0	82	bool pessimisticPass_;
michael@0	83	size_t count_;
michael@0	84
michael@0	85	public:
michael@0	86	ValueNumberer(MIRGenerator *mir, MIRGraph &graph, bool optimistic);
michael@0	87	bool analyze();
michael@0	88	bool clear();
michael@0	89	};
michael@0	90
michael@0	91	class ValueNumberData : public TempObject {
michael@0	92
michael@0	93	friend void ValueNumberer::breakClass(MDefinition*);
michael@0	94	friend MDefinition *ValueNumberer::findSplit(MDefinition*);
michael@0	95	uint32_t number;
michael@0	96	MDefinition *classNext;
michael@0	97	MDefinition *classPrev;
michael@0	98
michael@0	99	public:
michael@0	100	ValueNumberData() : number(0), classNext(nullptr), classPrev(nullptr) {}
michael@0	101
michael@0	102	void setValueNumber(uint32_t number_) {
michael@0	103	number = number_;
michael@0	104	}
michael@0	105
michael@0	106	uint32_t valueNumber() {
michael@0	107	return number;
michael@0	108	}
michael@0	109	// Set the class of this to the given representative value.
michael@0	110	void setClass(MDefinition *thisDef, MDefinition *rep) {
michael@0	111	JS_ASSERT(thisDef->valueNumberData() == this);
michael@0	112	// If we are attempting to insert ourself, then nothing needs to be done.
michael@0	113	// However, if the definition to be inserted already has the correct value number,
michael@0	114	// it still needs to be inserted, since the value number needs to be updated lazily.
michael@0	115	// this updating tactic can leave the world in a state where thisDef is not in the
michael@0	116	// equivalence class of rep, but it has the same value number. Defs in this state
michael@0	117	// need to be re-processed.
michael@0	118	if (this == rep->valueNumberData())
michael@0	119	return;
michael@0	120
michael@0	121	if (classNext)
michael@0	122	classNext->valueNumberData()->classPrev = classPrev;
michael@0	123	if (classPrev)
michael@0	124	classPrev->valueNumberData()->classNext = classNext;
michael@0	125
michael@0	126
michael@0	127	classPrev = rep;
michael@0	128	classNext = rep->valueNumberData()->classNext;
michael@0	129
michael@0	130	if (rep->valueNumberData()->classNext)
michael@0	131	rep->valueNumberData()->classNext->valueNumberData()->classPrev = thisDef;
michael@0	132	rep->valueNumberData()->classNext = thisDef;
michael@0	133	}
michael@0	134	};
michael@0	135	} // namespace jit
michael@0	136	} // namespace js
michael@0	137
michael@0	138	#endif /* jit_ValueNumbering_h */