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
|
//
// Copyright 2017 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.
//
// RemoveArrayLengthMethod.cpp:
// Fold array length expressions, including cases where the "this" node has side effects.
// Example:
// int i = (a = b).length();
// int j = (func()).length();
// becomes:
// (a = b);
// int i = <constant array length>;
// func();
// int j = <constant array length>;
//
// Must be run after SplitSequenceOperator, SimplifyLoopConditions and SeparateDeclarations steps
// have been done to expressions containing calls of the array length method.
//
// Does nothing to length method calls done on runtime-sized arrays.
#include "compiler/translator/tree_ops/RemoveArrayLengthMethod.h"
#include "compiler/translator/IntermNode.h"
#include "compiler/translator/tree_util/IntermTraverse.h"
namespace sh
{
namespace
{
class RemoveArrayLengthTraverser : public TIntermTraverser
{
public:
RemoveArrayLengthTraverser() : TIntermTraverser(true, false, false), mFoundArrayLength(false) {}
bool visitUnary(Visit visit, TIntermUnary *node) override;
void nextIteration() { mFoundArrayLength = false; }
bool foundArrayLength() const { return mFoundArrayLength; }
private:
void insertSideEffectsInParentBlock(TIntermTyped *node);
bool mFoundArrayLength;
};
bool RemoveArrayLengthTraverser::visitUnary(Visit visit, TIntermUnary *node)
{
// The only case where we leave array length() in place is for runtime-sized arrays.
if (node->getOp() == EOpArrayLength && !node->getOperand()->getType().isUnsizedArray())
{
mFoundArrayLength = true;
insertSideEffectsInParentBlock(node->getOperand());
TConstantUnion *constArray = new TConstantUnion[1];
constArray->setIConst(node->getOperand()->getOutermostArraySize());
queueReplacement(new TIntermConstantUnion(constArray, node->getType()),
OriginalNode::IS_DROPPED);
return false;
}
return true;
}
void RemoveArrayLengthTraverser::insertSideEffectsInParentBlock(TIntermTyped *node)
{
// If the node is an index type, traverse it and add the indices as side effects. If at the end
// an expression without side effect is encountered, such as an opaque uniform or a lone symbol,
// don't generate a statement for it.
if (!node->hasSideEffects())
{
return;
}
TIntermBinary *asBinary = node->getAsBinaryNode();
if (asBinary && !asBinary->isAssignment())
{
insertSideEffectsInParentBlock(asBinary->getLeft());
insertSideEffectsInParentBlock(asBinary->getRight());
}
else
{
insertStatementInParentBlock(node);
}
}
} // anonymous namespace
bool RemoveArrayLengthMethod(TCompiler *compiler, TIntermBlock *root)
{
RemoveArrayLengthTraverser traverser;
do
{
traverser.nextIteration();
root->traverse(&traverser);
if (traverser.foundArrayLength())
{
if (!traverser.updateTree(compiler, root))
{
return false;
}
}
} while (traverser.foundArrayLength());
return true;
}
} // namespace sh
|
