SPIRV-Tools/source/opt/local_single_block_elim_pass.h
dan sinclair f96b7f1cb9
use Pass::Run to set the context on each pass. (#1708)
Currently the IRContext is passed into the Pass::Process method. It is
then up to the individual pass to store the context into the context_
variable. This CL changes the Run method to store the context before
calling Process which no-longer receives the context as a parameter.
2018-07-12 09:08:45 -04:00

106 lines
4.0 KiB
C++

// Copyright (c) 2017 The Khronos Group Inc.
// Copyright (c) 2017 Valve Corporation
// Copyright (c) 2017 LunarG 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.
#ifndef LIBSPIRV_OPT_LOCAL_SINGLE_BLOCK_ELIM_PASS_H_
#define LIBSPIRV_OPT_LOCAL_SINGLE_BLOCK_ELIM_PASS_H_
#include <algorithm>
#include <map>
#include <queue>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include "basic_block.h"
#include "def_use_manager.h"
#include "mem_pass.h"
#include "module.h"
namespace spvtools {
namespace opt {
// See optimizer.hpp for documentation.
class LocalSingleBlockLoadStoreElimPass : public MemPass {
public:
LocalSingleBlockLoadStoreElimPass();
const char* name() const override { return "eliminate-local-single-block"; }
Status Process() override;
opt::IRContext::Analysis GetPreservedAnalyses() override {
return opt::IRContext::kAnalysisDefUse |
opt::IRContext::kAnalysisInstrToBlockMapping;
}
private:
// Return true if all uses of |varId| are only through supported reference
// operations ie. loads and store. Also cache in supported_ref_ptrs_.
// TODO(dnovillo): This function is replicated in other passes and it's
// slightly different in every pass. Is it possible to make one common
// implementation?
bool HasOnlySupportedRefs(uint32_t varId);
// On all entry point functions, within each basic block, eliminate
// loads and stores to function variables where possible. For
// loads, if previous load or store to same variable, replace
// load id with previous id and delete load. Finally, check if
// remaining stores are useless, and delete store and variable
// where possible. Assumes logical addressing.
bool LocalSingleBlockLoadStoreElim(opt::Function* func);
// Initialize extensions whitelist
void InitExtensions();
// Return true if all extensions in this module are supported by this pass.
bool AllExtensionsSupported() const;
void Initialize();
Pass::Status ProcessImpl();
// Map from function scope variable to a store of that variable in the
// current block whose value is currently valid. This map is cleared
// at the start of each block and incrementally updated as the block
// is scanned. The stores are candidates for elimination. The map is
// conservatively cleared when a function call is encountered.
std::unordered_map<uint32_t, opt::Instruction*> var2store_;
// Map from function scope variable to a load of that variable in the
// current block whose value is currently valid. This map is cleared
// at the start of each block and incrementally updated as the block
// is scanned. The stores are candidates for elimination. The map is
// conservatively cleared when a function call is encountered.
std::unordered_map<uint32_t, opt::Instruction*> var2load_;
// Set of variables whose most recent store in the current block cannot be
// deleted, for example, if there is a load of the variable which is
// dependent on the store and is not replaced and deleted by this pass,
// for example, a load through an access chain. A variable is removed
// from this set each time a new store of that variable is encountered.
std::unordered_set<uint32_t> pinned_vars_;
// Extensions supported by this pass.
std::unordered_set<std::string> extensions_whitelist_;
// Variables that are only referenced by supported operations for this
// pass ie. loads and stores.
std::unordered_set<uint32_t> supported_ref_ptrs_;
};
} // namespace opt
} // namespace spvtools
#endif // LIBSPIRV_OPT_LOCAL_SINGLE_BLOCK_ELIM_PASS_H_