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gfx/angle/src/compiler/UnfoldShortCircuit.cpp@141e0f1194b1 (annotated)

gfx/angle/src/compiler/UnfoldShortCircuit.cpp

Wed, 31 Dec 2014 07:16:47 +0100

author

Michael Schloh von Bennewitz <michael@schloh.com>

date

Wed, 31 Dec 2014 07:16:47 +0100

branch

TOR_BUG_9701

changeset 3

141e0f1194b1

permissions

-rw-r--r--

Revert simplistic fix pending revisit of Mozilla integration attempt.

michael@0	1	//
michael@0	2	// Copyright (c) 2002-2013 The ANGLE Project Authors. All rights reserved.
michael@0	3	// Use of this source code is governed by a BSD-style license that can be
michael@0	4	// found in the LICENSE file.
michael@0	5	//
michael@0	6	// UnfoldShortCircuit is an AST traverser to output short-circuiting operators as if-else statements.
michael@0	7	// The results are assigned to s# temporaries, which are used by the main translator instead of
michael@0	8	// the original expression.
michael@0	9	//
michael@0	10
michael@0	11	#include "compiler/UnfoldShortCircuit.h"
michael@0	12
michael@0	13	#include "compiler/InfoSink.h"
michael@0	14	#include "compiler/OutputHLSL.h"
michael@0	15
michael@0	16	namespace sh
michael@0	17	{
michael@0	18	UnfoldShortCircuit::UnfoldShortCircuit(TParseContext &context, OutputHLSL *outputHLSL) : mContext(context), mOutputHLSL(outputHLSL)
michael@0	19	{
michael@0	20	mTemporaryIndex = 0;
michael@0	21	}
michael@0	22
michael@0	23	void UnfoldShortCircuit::traverse(TIntermNode *node)
michael@0	24	{
michael@0	25	int rewindIndex = mTemporaryIndex;
michael@0	26	node->traverse(this);
michael@0	27	mTemporaryIndex = rewindIndex;
michael@0	28	}
michael@0	29
michael@0	30	bool UnfoldShortCircuit::visitBinary(Visit visit, TIntermBinary *node)
michael@0	31	{
michael@0	32	TInfoSinkBase &out = mOutputHLSL->getBodyStream();
michael@0	33
michael@0	34	switch (node->getOp())
michael@0	35	{
michael@0	36	case EOpLogicalOr:
michael@0	37	// "x || y" is equivalent to "x ? true : y", which unfolds to "bool s; if(x) s = true; else s = y;",
michael@0	38	// and then further simplifies down to "bool s = x; if(!s) s = y;".
michael@0	39	{
michael@0	40	int i = mTemporaryIndex;
michael@0	41
michael@0	42	out << "bool s" << i << ";\n";
michael@0	43
michael@0	44	out << "{\n";
michael@0	45
michael@0	46	mTemporaryIndex = i + 1;
michael@0	47	node->getLeft()->traverse(this);
michael@0	48	out << "s" << i << " = ";
michael@0	49	mTemporaryIndex = i + 1;
michael@0	50	node->getLeft()->traverse(mOutputHLSL);
michael@0	51	out << ";\n";
michael@0	52	out << "if(!s" << i << ")\n"
michael@0	53	"{\n";
michael@0	54	mTemporaryIndex = i + 1;
michael@0	55	node->getRight()->traverse(this);
michael@0	56	out << " s" << i << " = ";
michael@0	57	mTemporaryIndex = i + 1;
michael@0	58	node->getRight()->traverse(mOutputHLSL);
michael@0	59	out << ";\n"
michael@0	60	"}\n";
michael@0	61
michael@0	62	out << "}\n";
michael@0	63
michael@0	64	mTemporaryIndex = i + 1;
michael@0	65	}
michael@0	66	return false;
michael@0	67	case EOpLogicalAnd:
michael@0	68	// "x && y" is equivalent to "x ? y : false", which unfolds to "bool s; if(x) s = y; else s = false;",
michael@0	69	// and then further simplifies down to "bool s = x; if(s) s = y;".
michael@0	70	{
michael@0	71	int i = mTemporaryIndex;
michael@0	72
michael@0	73	out << "bool s" << i << ";\n";
michael@0	74
michael@0	75	out << "{\n";
michael@0	76
michael@0	77	mTemporaryIndex = i + 1;
michael@0	78	node->getLeft()->traverse(this);
michael@0	79	out << "s" << i << " = ";
michael@0	80	mTemporaryIndex = i + 1;
michael@0	81	node->getLeft()->traverse(mOutputHLSL);
michael@0	82	out << ";\n";
michael@0	83	out << "if(s" << i << ")\n"
michael@0	84	"{\n";
michael@0	85	mTemporaryIndex = i + 1;
michael@0	86	node->getRight()->traverse(this);
michael@0	87	out << " s" << i << " = ";
michael@0	88	mTemporaryIndex = i + 1;
michael@0	89	node->getRight()->traverse(mOutputHLSL);
michael@0	90	out << ";\n"
michael@0	91	"}\n";
michael@0	92
michael@0	93	out << "}\n";
michael@0	94
michael@0	95	mTemporaryIndex = i + 1;
michael@0	96	}
michael@0	97	return false;
michael@0	98	default:
michael@0	99	return true;
michael@0	100	}
michael@0	101	}
michael@0	102
michael@0	103	bool UnfoldShortCircuit::visitSelection(Visit visit, TIntermSelection *node)
michael@0	104	{
michael@0	105	TInfoSinkBase &out = mOutputHLSL->getBodyStream();
michael@0	106
michael@0	107	// Unfold "b ? x : y" into "type s; if(b) s = x; else s = y;"
michael@0	108	if (node->usesTernaryOperator())
michael@0	109	{
michael@0	110	int i = mTemporaryIndex;
michael@0	111
michael@0	112	out << mOutputHLSL->typeString(node->getType()) << " s" << i << ";\n";
michael@0	113
michael@0	114	out << "{\n";
michael@0	115
michael@0	116	mTemporaryIndex = i + 1;
michael@0	117	node->getCondition()->traverse(this);
michael@0	118	out << "if(";
michael@0	119	mTemporaryIndex = i + 1;
michael@0	120	node->getCondition()->traverse(mOutputHLSL);
michael@0	121	out << ")\n"
michael@0	122	"{\n";
michael@0	123	mTemporaryIndex = i + 1;
michael@0	124	node->getTrueBlock()->traverse(this);
michael@0	125	out << " s" << i << " = ";
michael@0	126	mTemporaryIndex = i + 1;
michael@0	127	node->getTrueBlock()->traverse(mOutputHLSL);
michael@0	128	out << ";\n"
michael@0	129	"}\n"
michael@0	130	"else\n"
michael@0	131	"{\n";
michael@0	132	mTemporaryIndex = i + 1;
michael@0	133	node->getFalseBlock()->traverse(this);
michael@0	134	out << " s" << i << " = ";
michael@0	135	mTemporaryIndex = i + 1;
michael@0	136	node->getFalseBlock()->traverse(mOutputHLSL);
michael@0	137	out << ";\n"
michael@0	138	"}\n";
michael@0	139
michael@0	140	out << "}\n";
michael@0	141
michael@0	142	mTemporaryIndex = i + 1;
michael@0	143	}
michael@0	144
michael@0	145	return false;
michael@0	146	}
michael@0	147
michael@0	148	bool UnfoldShortCircuit::visitLoop(Visit visit, TIntermLoop *node)
michael@0	149	{
michael@0	150	int rewindIndex = mTemporaryIndex;
michael@0	151
michael@0	152	if (node->getInit())
michael@0	153	{
michael@0	154	node->getInit()->traverse(this);
michael@0	155	}
michael@0	156
michael@0	157	if (node->getCondition())
michael@0	158	{
michael@0	159	node->getCondition()->traverse(this);
michael@0	160	}
michael@0	161
michael@0	162	if (node->getExpression())
michael@0	163	{
michael@0	164	node->getExpression()->traverse(this);
michael@0	165	}
michael@0	166
michael@0	167	mTemporaryIndex = rewindIndex;
michael@0	168
michael@0	169	return false;
michael@0	170	}
michael@0	171
michael@0	172	int UnfoldShortCircuit::getNextTemporaryIndex()
michael@0	173	{
michael@0	174	return mTemporaryIndex++;
michael@0	175	}
michael@0	176	}