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
141
142
143
144
145
/*
* Copyright 2023 WebAssembly Community Group participants
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "stringify-walker.h"
#ifndef wasm_passes_stringify_walker_impl_h
#define wasm_passes_stringify_walker_impl_h
namespace wasm {
// This walker supplies its own doWalkModule because it does not make sense to
// walk anything besides defined functions.
template<typename SubType>
inline void StringifyWalker<SubType>::doWalkModule(Module* module) {
ModuleUtils::iterDefinedFunctions(
*module, [&](Function* func) { this->walkFunction(func); });
}
template<typename SubType>
inline void StringifyWalker<SubType>::doWalkFunction(Function* func) {
walk(func->body);
/*
* We add a unique symbol after walking the function body to separate the
* string generated from visiting the function body as a single unit from the
* subsequent strings that will be generated from visiting the sub-expressions
* of the function body. If we did not add this unique symbol and a program
* had two functions with the same instructions, we would incorrectly create a
* new function with the instructions repeated twice.
*
* It might be helpful to think of the function body as a block that needs to
* be separated from subsequent instructions.
*/
addUniqueSymbol();
}
template<typename SubType>
inline void StringifyWalker<SubType>::walk(Expression* curr) {
Super::walk(curr);
do {
addUniqueSymbol();
dequeueControlFlow();
} while (!controlFlowQueue.empty());
}
template<typename SubType>
inline void StringifyWalker<SubType>::scan(SubType* self, Expression** currp) {
Expression* curr = *currp;
if (Properties::isControlFlowStructure(curr)) {
self->controlFlowQueue.push(currp);
self->pushTask(doVisitExpression, currp);
// The if-condition is a value child consumed by the if control flow, which
// makes the if-condition a true sibling rather than part of its contents in
// the binary format
for (auto*& child : ValueChildIterator(curr)) {
Super::scan(self, &child);
}
} else {
Super::scan(self, currp);
}
}
// This dequeueControlFlow is responsible for visiting the children expressions
// of control flow.
template<typename SubType> void StringifyWalker<SubType>::dequeueControlFlow() {
auto& queue = controlFlowQueue;
if (queue.empty()) {
return;
}
Expression** currp = queue.front();
queue.pop();
Expression* curr = *currp;
// TODO: Issue #5796, Make a ControlChildIterator
switch (curr->_id) {
case Expression::Id::BlockId: {
auto* block = curr->cast<Block>();
for (auto& child : block->list) {
Super::walk(child);
}
break;
}
case Expression::Id::IfId: {
auto* iff = curr->cast<If>();
Super::walk(iff->ifTrue);
if (iff->ifFalse) {
addUniqueSymbol();
Super::walk(iff->ifFalse);
}
break;
}
case Expression::Id::TryId: {
auto* tryy = curr->cast<Try>();
Super::walk(tryy->body);
for (auto& child : tryy->catchBodies) {
addUniqueSymbol();
Super::walk(child);
}
break;
}
case Expression::Id::LoopId: {
auto* loop = curr->cast<Loop>();
Super::walk(loop->body);
break;
}
default: {
assert(Properties::isControlFlowStructure(curr));
WASM_UNREACHABLE("unexpected expression");
}
}
}
template<typename SubType>
void StringifyWalker<SubType>::doVisitExpression(SubType* self,
Expression** currp) {
Expression* curr = *currp;
self->visit(curr);
}
template<typename SubType>
inline void StringifyWalker<SubType>::addUniqueSymbol() {
// TODO: Add the following static_assert when the compilers running our GitHub
// actions are updated enough to know that this is a constant condition:
// static_assert(&StringifyWalker<SubType>::addUniqueSymbol !=
// &SubType::addUniqueSymbol);
auto self = static_cast<SubType*>(this);
self->addUniqueSymbol();
}
} // namespace wasm
#endif // wasm_passes_stringify_walker_impl_h