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https://github.com/KhronosGroup/SPIRV-Tools
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5834719fc1
There does not seem to be any pass that remove global variables. I think we could use one. This pass will look specifically for global variables that are not referenced and are not exported. Any decoration associated with the variable will also be removed. However, this could cause types or constants to become unreferenced. They will not be removed. Another pass will have to be called to remove those.
52 lines
1.7 KiB
C++
52 lines
1.7 KiB
C++
// Copyright (c) 2017 Google 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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#ifndef SPIRV_TOOLS_DEAD_VARIABLE_ELIMINATION_H
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#define SPIRV_TOOLS_DEAD_VARIABLE_ELIMINATION_H
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#include <unordered_map>
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#include <climits>
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#include "decoration_manager.h"
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#include "mem_pass.h"
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namespace spvtools {
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namespace opt {
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class DeadVariableElimination : public MemPass {
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public:
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const char* name() const override { return "dead-variable-elimination"; }
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Status Process(ir::Module*) override;
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private:
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// Deletes the OpVariable instruction who result id is |result_id|.
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void DeleteVariable(uint32_t result_id);
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// Keeps track of the number of references of an id. Once that value is 0, it
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// is safe to remove the corresponding instruction.
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//
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// Note that the special value kMustKeep is used to indicate that the
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// instruction cannot be deleted for reasons other that is being explicitly
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// referenced.
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std::unordered_map<uint32_t, size_t> reference_count_;
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// Special value used to indicate that an id cannot be safely deleted.
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enum { kMustKeep = INT_MAX };
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};
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} // namespace opt
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} // namespace spvtools
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#endif // SPIRV_TOOLS_DEAD_VARIABLE_ELIMINATION_H
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