SPIRV-Tools/source/opt/eliminate_dead_functions_pass.cpp
Steven Perron f32d11f74b Add the IRContext (part 2): Add def-use manager
This change will move the instances of the def-use manager to the
IRContext.  This allows it to persists across optimization, and does
not have to be rebuilt multiple times.

Added test to ensure that the IRContext is validating and invalidating
the analyses correctly.
2017-11-08 13:35:34 -05:00

61 lines
1.8 KiB
C++

// Copyright (c) 2017 Google Inc.
//
// 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 "eliminate_dead_functions_pass.h"
#include <unordered_set>
namespace spvtools {
namespace opt {
Pass::Status EliminateDeadFunctionsPass::Process(ir::IRContext* c) {
InitializeProcessing(c);
// Identify live functions first. Those that are not live
// are dead.
std::unordered_set<const ir::Function*> live_function_set;
ProcessFunction mark_live = [&live_function_set](ir::Function* fp) {
live_function_set.insert(fp);
return false;
};
ProcessReachableCallTree(mark_live, context());
bool modified = false;
for (auto funcIter = get_module()->begin();
funcIter != get_module()->end();) {
if (live_function_set.count(&*funcIter) == 0) {
modified = true;
EliminateFunction(&*funcIter);
funcIter = funcIter.Erase();
} else {
++funcIter;
}
}
return modified ? Pass::Status::SuccessWithChange
: Pass::Status::SuccessWithoutChange;
}
void EliminateDeadFunctionsPass::EliminateFunction(ir::Function* func) {
// Remove all of the instruction in the function body
func->ForEachInst(
[this](ir::Instruction* inst) {
KillNamesAndDecorates(inst);
context()->KillInst(inst);
},
true);
}
} // namespace opt
} // namespace spvtools