llvm-project/mlir/lib/IR/SymbolTable.cpp

74 lines
2.7 KiB
C++

//===- SymbolTable.cpp - MLIR Symbol Table Class --------------------------===//
//
// Copyright 2019 The MLIR Authors.
//
// 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 "mlir/IR/SymbolTable.h"
#include "mlir/IR/Module.h"
using namespace mlir;
/// Build a symbol table with the symbols within the given module.
SymbolTable::SymbolTable(ModuleOp module) : context(module.getContext()) {
for (auto func : module) {
auto inserted = symbolTable.insert({func.getName(), func});
(void)inserted;
assert(inserted.second &&
"expected module to contain uniquely named functions");
}
}
/// Look up a symbol with the specified name, returning null if no such name
/// exists. Names never include the @ on them.
Function SymbolTable::lookup(StringRef name) const {
return symbolTable.lookup(name);
}
/// Look up a symbol with the specified name, returning null if no such name
/// exists. Names never include the @ on them.
Function SymbolTable::lookup(Identifier name) const {
return lookup(name.strref());
}
/// Erase the given symbol from the table.
void SymbolTable::erase(Function symbol) {
auto it = symbolTable.find(symbol.getName());
if (it != symbolTable.end() && it->second == symbol)
symbolTable.erase(it);
}
/// Insert a new symbol into the table, and rename it as necessary to avoid
/// collisions.
void SymbolTable::insert(Function symbol) {
// Add this symbol to the symbol table, uniquing the name if a conflict is
// detected.
if (symbolTable.insert({symbol.getName(), symbol}).second)
return;
// If a conflict was detected, then the function will not have been added to
// the symbol table. Try suffixes until we get to a unique name that works.
SmallString<128> nameBuffer(symbol.getName());
unsigned originalLength = nameBuffer.size();
// Iteratively try suffixes until we find one that isn't used. We use a
// module level uniquing counter to avoid N^2 behavior.
do {
nameBuffer.resize(originalLength);
nameBuffer += '_';
nameBuffer += std::to_string(uniquingCounter++);
} while (!symbolTable.insert({nameBuffer, symbol}).second);
symbol.setName(nameBuffer);
}