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
|
/*
* Copyright 2019 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.
*/
//
// Turn indirect calls into direct calls. This is possible if we know
// the table cannot change, and if we see a constant argument for the
// indirect call's index.
//
#include <unordered_map>
#include "asm_v_wasm.h"
#include "ir/table-utils.h"
#include "ir/utils.h"
#include "pass.h"
#include "wasm-builder.h"
#include "wasm-traversal.h"
#include "wasm.h"
namespace wasm {
namespace {
struct FunctionDirectizer : public WalkerPass<PostWalker<FunctionDirectizer>> {
bool isFunctionParallel() override { return true; }
Pass* create() override { return new FunctionDirectizer(flatTable); }
FunctionDirectizer(FlatTable* flatTable) : flatTable(flatTable) {}
void visitCallIndirect(CallIndirect* curr) {
if (auto* c = curr->target->dynCast<Const>()) {
Index index = c->value.geti32();
// If the index is invalid, or the type is wrong, we can
// emit an unreachable here, since in Binaryen it is ok to
// reorder/replace traps when optimizing (but never to
// remove them, at least not by default).
if (index >= flatTable->names.size()) {
replaceWithUnreachable(curr);
return;
}
auto name = flatTable->names[index];
if (!name.is()) {
replaceWithUnreachable(curr);
return;
}
auto* func = getModule()->getFunction(name);
if (getSig(getModule()->getFunctionType(curr->fullType)) !=
getSig(func)) {
replaceWithUnreachable(curr);
return;
}
// Everything looks good!
replaceCurrent(
Builder(*getModule()).makeCall(name, curr->operands, curr->type));
}
}
void doWalkFunction(Function* func) {
WalkerPass<PostWalker<FunctionDirectizer>>::doWalkFunction(func);
if (changedTypes) {
ReFinalize().walkFunctionInModule(func, getModule());
}
}
private:
FlatTable* flatTable;
bool changedTypes = false;
void replaceWithUnreachable(CallIndirect* call) {
Builder builder(*getModule());
for (auto*& operand : call->operands) {
operand = builder.makeDrop(operand);
}
replaceCurrent(builder.makeSequence(builder.makeBlock(call->operands),
builder.makeUnreachable()));
changedTypes = true;
}
};
struct Directize : public Pass {
void run(PassRunner* runner, Module* module) override {
if (!module->table.exists)
return;
if (module->table.imported())
return;
for (auto& ex : module->exports) {
if (ex->kind == ExternalKind::Table)
return;
}
FlatTable flatTable(module->table);
if (!flatTable.valid)
return;
// The table exists and is constant, so this is possible.
{
PassRunner runner(module);
runner.setIsNested(true);
runner.add<FunctionDirectizer>(&flatTable);
runner.run();
}
}
};
} // anonymous namespace
Pass* createDirectizePass() { return new Directize(); }
} // namespace wasm
|
