1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/angle/src/compiler/UnfoldShortCircuit.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,176 @@
1.4 +//
1.5 +// Copyright (c) 2002-2013 The ANGLE Project Authors. All rights reserved.
1.6 +// Use of this source code is governed by a BSD-style license that can be
1.7 +// found in the LICENSE file.
1.8 +//
1.9 +// UnfoldShortCircuit is an AST traverser to output short-circuiting operators as if-else statements.
1.10 +// The results are assigned to s# temporaries, which are used by the main translator instead of
1.11 +// the original expression.
1.12 +//
1.13 +
1.14 +#include "compiler/UnfoldShortCircuit.h"
1.15 +
1.16 +#include "compiler/InfoSink.h"
1.17 +#include "compiler/OutputHLSL.h"
1.18 +
1.19 +namespace sh
1.20 +{
1.21 +UnfoldShortCircuit::UnfoldShortCircuit(TParseContext &context, OutputHLSL *outputHLSL) : mContext(context), mOutputHLSL(outputHLSL)
1.22 +{
1.23 + mTemporaryIndex = 0;
1.24 +}
1.25 +
1.26 +void UnfoldShortCircuit::traverse(TIntermNode *node)
1.27 +{
1.28 + int rewindIndex = mTemporaryIndex;
1.29 + node->traverse(this);
1.30 + mTemporaryIndex = rewindIndex;
1.31 +}
1.32 +
1.33 +bool UnfoldShortCircuit::visitBinary(Visit visit, TIntermBinary *node)
1.34 +{
1.35 + TInfoSinkBase &out = mOutputHLSL->getBodyStream();
1.36 +
1.37 + switch (node->getOp())
1.38 + {
1.39 + case EOpLogicalOr:
1.40 + // "x || y" is equivalent to "x ? true : y", which unfolds to "bool s; if(x) s = true; else s = y;",
1.41 + // and then further simplifies down to "bool s = x; if(!s) s = y;".
1.42 + {
1.43 + int i = mTemporaryIndex;
1.44 +
1.45 + out << "bool s" << i << ";\n";
1.46 +
1.47 + out << "{\n";
1.48 +
1.49 + mTemporaryIndex = i + 1;
1.50 + node->getLeft()->traverse(this);
1.51 + out << "s" << i << " = ";
1.52 + mTemporaryIndex = i + 1;
1.53 + node->getLeft()->traverse(mOutputHLSL);
1.54 + out << ";\n";
1.55 + out << "if(!s" << i << ")\n"
1.56 + "{\n";
1.57 + mTemporaryIndex = i + 1;
1.58 + node->getRight()->traverse(this);
1.59 + out << " s" << i << " = ";
1.60 + mTemporaryIndex = i + 1;
1.61 + node->getRight()->traverse(mOutputHLSL);
1.62 + out << ";\n"
1.63 + "}\n";
1.64 +
1.65 + out << "}\n";
1.66 +
1.67 + mTemporaryIndex = i + 1;
1.68 + }
1.69 + return false;
1.70 + case EOpLogicalAnd:
1.71 + // "x && y" is equivalent to "x ? y : false", which unfolds to "bool s; if(x) s = y; else s = false;",
1.72 + // and then further simplifies down to "bool s = x; if(s) s = y;".
1.73 + {
1.74 + int i = mTemporaryIndex;
1.75 +
1.76 + out << "bool s" << i << ";\n";
1.77 +
1.78 + out << "{\n";
1.79 +
1.80 + mTemporaryIndex = i + 1;
1.81 + node->getLeft()->traverse(this);
1.82 + out << "s" << i << " = ";
1.83 + mTemporaryIndex = i + 1;
1.84 + node->getLeft()->traverse(mOutputHLSL);
1.85 + out << ";\n";
1.86 + out << "if(s" << i << ")\n"
1.87 + "{\n";
1.88 + mTemporaryIndex = i + 1;
1.89 + node->getRight()->traverse(this);
1.90 + out << " s" << i << " = ";
1.91 + mTemporaryIndex = i + 1;
1.92 + node->getRight()->traverse(mOutputHLSL);
1.93 + out << ";\n"
1.94 + "}\n";
1.95 +
1.96 + out << "}\n";
1.97 +
1.98 + mTemporaryIndex = i + 1;
1.99 + }
1.100 + return false;
1.101 + default:
1.102 + return true;
1.103 + }
1.104 +}
1.105 +
1.106 +bool UnfoldShortCircuit::visitSelection(Visit visit, TIntermSelection *node)
1.107 +{
1.108 + TInfoSinkBase &out = mOutputHLSL->getBodyStream();
1.109 +
1.110 + // Unfold "b ? x : y" into "type s; if(b) s = x; else s = y;"
1.111 + if (node->usesTernaryOperator())
1.112 + {
1.113 + int i = mTemporaryIndex;
1.114 +
1.115 + out << mOutputHLSL->typeString(node->getType()) << " s" << i << ";\n";
1.116 +
1.117 + out << "{\n";
1.118 +
1.119 + mTemporaryIndex = i + 1;
1.120 + node->getCondition()->traverse(this);
1.121 + out << "if(";
1.122 + mTemporaryIndex = i + 1;
1.123 + node->getCondition()->traverse(mOutputHLSL);
1.124 + out << ")\n"
1.125 + "{\n";
1.126 + mTemporaryIndex = i + 1;
1.127 + node->getTrueBlock()->traverse(this);
1.128 + out << " s" << i << " = ";
1.129 + mTemporaryIndex = i + 1;
1.130 + node->getTrueBlock()->traverse(mOutputHLSL);
1.131 + out << ";\n"
1.132 + "}\n"
1.133 + "else\n"
1.134 + "{\n";
1.135 + mTemporaryIndex = i + 1;
1.136 + node->getFalseBlock()->traverse(this);
1.137 + out << " s" << i << " = ";
1.138 + mTemporaryIndex = i + 1;
1.139 + node->getFalseBlock()->traverse(mOutputHLSL);
1.140 + out << ";\n"
1.141 + "}\n";
1.142 +
1.143 + out << "}\n";
1.144 +
1.145 + mTemporaryIndex = i + 1;
1.146 + }
1.147 +
1.148 + return false;
1.149 +}
1.150 +
1.151 +bool UnfoldShortCircuit::visitLoop(Visit visit, TIntermLoop *node)
1.152 +{
1.153 + int rewindIndex = mTemporaryIndex;
1.154 +
1.155 + if (node->getInit())
1.156 + {
1.157 + node->getInit()->traverse(this);
1.158 + }
1.159 +
1.160 + if (node->getCondition())
1.161 + {
1.162 + node->getCondition()->traverse(this);
1.163 + }
1.164 +
1.165 + if (node->getExpression())
1.166 + {
1.167 + node->getExpression()->traverse(this);
1.168 + }
1.169 +
1.170 + mTemporaryIndex = rewindIndex;
1.171 +
1.172 + return false;
1.173 +}
1.174 +
1.175 +int UnfoldShortCircuit::getNextTemporaryIndex()
1.176 +{
1.177 + return mTemporaryIndex++;
1.178 +}
1.179 +}
