SPIRV-Tools/source/opt/eliminate_dead_functions_pass.cpp
Steven Perron eb4653a67f Add the decoration manager to the IRContext.
To make the decoration manger available everywhere, and to reduce the
number of times it needs to be build, I add one the IRContext.

As the same time, I move code that modifies decoration instruction into
the IRContext from mempass and the decoration manager.  This will make
it easier to keep everything up to date.

This should take care of issue #928.
2017-11-15 12:48:03 -05:00

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// 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 "ir_context.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) {
context()->KillInst(inst);
},
true);
}
} // namespace opt
} // namespace spvtools