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/*
* 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 <unordered_map>
#include "analysis/cfg.h"
#include "cfg/cfg-traversal.h"
#include "wasm-stack.h"
namespace wasm::analysis {
CFG CFG::fromFunction(Function* func) {
struct CFGBuilder : CFGWalker<CFGBuilder,
UnifiedExpressionVisitor<CFGBuilder>,
std::vector<Expression*>> {
void visitExpression(Expression* curr) {
if (currBasicBlock) {
currBasicBlock->contents.push_back(curr);
}
}
};
CFGBuilder builder;
builder.walkFunction(func);
size_t numBlocks = builder.basicBlocks.size();
CFG cfg;
cfg.blocks = std::vector<BasicBlock>(numBlocks);
// From here the addresses of the new basic blocks are stable.
std::unordered_map<CFGBuilder::BasicBlock*, BasicBlock*> oldToNewBlocks;
for (size_t i = 0; i < numBlocks; ++i) {
oldToNewBlocks[builder.basicBlocks[i].get()] = &cfg.blocks[i];
}
for (size_t i = 0; i < numBlocks; ++i) {
auto& oldBlock = *builder.basicBlocks[i];
auto& newBlock = cfg.blocks[i];
newBlock.index = i;
newBlock.insts = std::move(oldBlock.contents);
newBlock.predecessors.reserve(oldBlock.in.size());
for (auto* oldPred : oldBlock.in) {
newBlock.predecessors.push_back(oldToNewBlocks.at(oldPred));
}
newBlock.successors.reserve(oldBlock.out.size());
for (auto* oldSucc : oldBlock.out) {
newBlock.successors.push_back(oldToNewBlocks.at(oldSucc));
}
}
assert(!cfg.blocks.empty());
cfg.blocks[0].entry = true;
if (builder.exit) {
oldToNewBlocks.at(builder.exit)->exit = true;
}
// Move-construct a new CFG to get mandatory copy elision, preserving basic
// block addresses through the return.
return CFG(std::move(cfg));
}
void CFG::print(std::ostream& os, Module* wasm) const {
size_t start = 0;
for (auto& block : *this) {
if (&block != &*begin()) {
os << '\n';
}
block.print(os, wasm, start);
start += block.size();
}
}
void BasicBlock::print(std::ostream& os, Module* wasm, size_t start) const {
os << ";; preds: [";
for (const auto* pred : preds()) {
if (pred != *preds().begin()) {
os << ", ";
}
os << pred->index;
}
os << "], succs: [";
for (const auto* succ : succs()) {
if (succ != *succs().begin()) {
os << ", ";
}
os << succ->index;
}
os << "]\n";
if (isEntry()) {
os << ";; entry\n";
}
if (isExit()) {
os << ";; exit\n";
}
os << index << ":\n";
size_t instIndex = start;
for (auto* inst : *this) {
os << " " << instIndex++ << ": " << ShallowExpression{inst, wasm} << '\n';
}
}
CFGBlockIndexes::CFGBlockIndexes(const CFG& cfg) {
for (auto& block : cfg) {
for (auto* expr : block) {
map[expr] = block.getIndex();
}
}
}
} // namespace wasm::analysis
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