1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
|
//
// Copyright (c) 2014 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// RewriteElseBlocks.cpp: Implementation for tree transform to change
// all if-else blocks to if-if blocks.
//
#include "compiler/translator/RewriteElseBlocks.h"
#include "compiler/translator/NodeSearch.h"
#include "compiler/translator/SymbolTable.h"
namespace sh
{
namespace
{
class ElseBlockRewriter : public TIntermTraverser
{
public:
ElseBlockRewriter();
protected:
bool visitAggregate(Visit visit, TIntermAggregate *aggregate) override;
private:
const TType *mFunctionType;
TIntermNode *rewriteSelection(TIntermSelection *selection);
};
TIntermUnary *MakeNewUnary(TOperator op, TIntermTyped *operand)
{
TIntermUnary *unary = new TIntermUnary(op, operand->getType());
unary->setOperand(operand);
return unary;
}
ElseBlockRewriter::ElseBlockRewriter()
: TIntermTraverser(true, false, true),
mFunctionType(NULL)
{}
bool ElseBlockRewriter::visitAggregate(Visit visit, TIntermAggregate *node)
{
switch (node->getOp())
{
case EOpSequence:
if (visit == PostVisit)
{
for (size_t statementIndex = 0; statementIndex != node->getSequence()->size(); statementIndex++)
{
TIntermNode *statement = (*node->getSequence())[statementIndex];
TIntermSelection *selection = statement->getAsSelectionNode();
if (selection && selection->getFalseBlock() != nullptr)
{
// Check for if / else if
TIntermSelection *elseIfBranch = selection->getFalseBlock()->getAsSelectionNode();
if (elseIfBranch)
{
selection->replaceChildNode(elseIfBranch, rewriteSelection(elseIfBranch));
delete elseIfBranch;
}
(*node->getSequence())[statementIndex] = rewriteSelection(selection);
delete selection;
}
}
}
break;
case EOpFunction:
// Store the current function context (see comment below)
mFunctionType = ((visit == PreVisit) ? &node->getType() : NULL);
break;
default: break;
}
return true;
}
TIntermNode *ElseBlockRewriter::rewriteSelection(TIntermSelection *selection)
{
ASSERT(selection != nullptr);
nextTemporaryIndex();
TIntermTyped *typedCondition = selection->getCondition()->getAsTyped();
TIntermAggregate *storeCondition = createTempInitDeclaration(typedCondition);
TIntermSelection *falseBlock = nullptr;
TType boolType(EbtBool, EbpUndefined, EvqTemporary);
if (selection->getFalseBlock())
{
TIntermAggregate *negatedElse = nullptr;
// crbug.com/346463
// D3D generates error messages claiming a function has no return value, when rewriting
// an if-else clause that returns something non-void in a function. By appending dummy
// returns (that are unreachable) we can silence this compile error.
if (mFunctionType && mFunctionType->getBasicType() != EbtVoid)
{
TString typeString = mFunctionType->getStruct() ? mFunctionType->getStruct()->name() :
mFunctionType->getBasicString();
TString rawText = "return (" + typeString + ")0";
TIntermRaw *returnNode = new TIntermRaw(*mFunctionType, rawText);
negatedElse = new TIntermAggregate(EOpSequence);
negatedElse->getSequence()->push_back(returnNode);
}
TIntermSymbol *conditionSymbolElse = createTempSymbol(boolType);
TIntermUnary *negatedCondition = MakeNewUnary(EOpLogicalNot, conditionSymbolElse);
falseBlock = new TIntermSelection(negatedCondition,
selection->getFalseBlock(), negatedElse);
}
TIntermSymbol *conditionSymbolSel = createTempSymbol(boolType);
TIntermSelection *newSelection = new TIntermSelection(conditionSymbolSel, selection->getTrueBlock(), falseBlock);
TIntermAggregate *block = new TIntermAggregate(EOpSequence);
block->getSequence()->push_back(storeCondition);
block->getSequence()->push_back(newSelection);
return block;
}
}
void RewriteElseBlocks(TIntermNode *node, unsigned int *temporaryIndex)
{
ElseBlockRewriter rewriter;
rewriter.useTemporaryIndex(temporaryIndex);
node->traverse(&rewriter);
}
}
|
