mirror of
https://github.com/KhronosGroup/SPIRV-Tools
synced 2024-11-27 13:50:07 +00:00
e43c91046b
Creates a pass called eliminate dead functions that looks for functions that could never be called, and deletes them from the module. To support this change a new function was added to the Pass class to traverse the call trees from diffent starting points. Includes a test to ensure that annotations are removed when deleting a dead function. They were not, so fixed that up as well. Did some cleanup of the assembly for the test in pass_test.cpp. Trying to make them smaller and easier to read.
103 lines
3.3 KiB
C++
103 lines
3.3 KiB
C++
// Copyright (c) 2017 The Khronos Group Inc.
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// Copyright (c) 2017 Valve Corporation
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// Copyright (c) 2017 LunarG Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "pass.h"
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#include "iterator.h"
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namespace spvtools {
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namespace opt {
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namespace {
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const uint32_t kEntryPointFunctionIdInIdx = 1;
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} // namespace
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void Pass::AddCalls(ir::Function* func, std::queue<uint32_t>* todo) {
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for (auto bi = func->begin(); bi != func->end(); ++bi)
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for (auto ii = bi->begin(); ii != bi->end(); ++ii)
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if (ii->opcode() == SpvOpFunctionCall)
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todo->push(ii->GetSingleWordInOperand(0));
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}
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bool Pass::ProcessEntryPointCallTree(ProcessFunction& pfn, ir::Module* module) {
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// Map from function's result id to function
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std::unordered_map<uint32_t, ir::Function*> id2function;
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for (auto& fn : *module) id2function[fn.result_id()] = &fn;
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// Collect all of the entry points as the roots.
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std::queue<uint32_t> roots;
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for (auto& e : module->entry_points())
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roots.push(e.GetSingleWordInOperand(kEntryPointFunctionIdInIdx));
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return ProcessCallTreeFromRoots(pfn, id2function, &roots);
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}
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bool Pass::ProcessReachableCallTree(ProcessFunction& pfn, ir::Module* module) {
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// Map from function's result id to function
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std::unordered_map<uint32_t, ir::Function*> id2function;
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for (auto& fn : *module) id2function[fn.result_id()] = &fn;
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std::queue<uint32_t> roots;
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// Add all entry points since they can be reached from outside the module.
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for (auto& e : module->entry_points())
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roots.push(e.GetSingleWordInOperand(kEntryPointFunctionIdInIdx));
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// Add all exported functions since they can be reached from outside the
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// module.
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for (auto& a : module->annotations()) {
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// TODO: Handle group decorations as well. Currently not generate by any
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// front-end, but could be coming.
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if (a.opcode() == SpvOp::SpvOpDecorate) {
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if (a.GetSingleWordOperand(1) ==
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SpvDecoration::SpvDecorationLinkageAttributes) {
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uint32_t lastOperand = a.NumOperands() - 1;
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if (a.GetSingleWordOperand(lastOperand) ==
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SpvLinkageType::SpvLinkageTypeExport) {
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uint32_t id = a.GetSingleWordOperand(0);
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if (id2function.count(id) != 0) roots.push(id);
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}
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}
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}
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}
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return ProcessCallTreeFromRoots(pfn, id2function, &roots);
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}
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bool Pass::ProcessCallTreeFromRoots(
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ProcessFunction& pfn,
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const std::unordered_map<uint32_t, ir::Function*>& id2function,
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std::queue<uint32_t>* roots) {
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// Process call tree
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bool modified = false;
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std::unordered_set<uint32_t> done;
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while (!roots->empty()) {
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const uint32_t fi = roots->front();
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roots->pop();
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if (done.insert(fi).second) {
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ir::Function* fn = id2function.at(fi);
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modified = pfn(fn) || modified;
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AddCalls(fn, roots);
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}
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}
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return modified;
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}
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} // namespace opt
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} // namespace spvtools
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