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/*
* Copyright 2018 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.
*/
//
// Removes the `f32.copysign` and `f64.copysign` instructions and replaces them
// with equivalent bit operations. Primarily intended to be used with `wasm2asm`
// where `Math.copysign` doesn't exist.
//
#include <wasm.h>
#include <pass.h>
#include "wasm-builder.h"
namespace wasm {
struct RemoveCopysignPass : public WalkerPass<PostWalker<RemoveCopysignPass>> {
bool isFunctionParallel() override { return false; }
Pass* create() override { return new RemoveCopysignPass; }
void doWalkModule(Module* module) {
if (!builder) builder = make_unique<Builder>(*module);
PostWalker<RemoveCopysignPass>::doWalkModule(module);
}
void doWalkFunction(Function* func) {
if (!builder) builder = make_unique<Builder>(*getModule());
PostWalker<RemoveCopysignPass>::doWalkFunction(func);
}
void visitBinary(Binary *curr) {
Literal signBit, otherBits;
UnaryOp int2float, float2int;
BinaryOp bitAnd, bitOr;
switch (curr->op) {
case CopySignFloat32:
float2int = ReinterpretFloat32;
int2float = ReinterpretInt32;
bitAnd = AndInt32;
bitOr = OrInt32;
signBit = Literal(uint32_t(1 << 31));
otherBits = Literal(uint32_t(1 << 31) - 1);
break;
case CopySignFloat64:
float2int = ReinterpretFloat64;
int2float = ReinterpretInt64;
bitAnd = AndInt64;
bitOr = OrInt64;
signBit = Literal(uint64_t(1) << 63);
otherBits = Literal((uint64_t(1) << 63) - 1);
break;
default: return;
}
replaceCurrent(
builder->makeUnary(
int2float,
builder->makeBinary(
bitOr,
builder->makeBinary(
bitAnd,
builder->makeUnary(
float2int,
curr->left
),
builder->makeConst(otherBits)
),
builder->makeBinary(
bitAnd,
builder->makeUnary(
float2int,
curr->right
),
builder->makeConst(signBit)
)
)
)
);
}
private:
std::unique_ptr<Builder> builder;
};
Pass *createRemoveCopysignPass() {
return new RemoveCopysignPass();
}
} // namespace wasm
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