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Diffstat (limited to '3rdparty/bgfx/3rdparty/spirv-tools/source/opt/code_sink.h')
-rw-r--r-- | 3rdparty/bgfx/3rdparty/spirv-tools/source/opt/code_sink.h | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/3rdparty/bgfx/3rdparty/spirv-tools/source/opt/code_sink.h b/3rdparty/bgfx/3rdparty/spirv-tools/source/opt/code_sink.h new file mode 100644 index 00000000000..d24df030dff --- /dev/null +++ b/3rdparty/bgfx/3rdparty/spirv-tools/source/opt/code_sink.h @@ -0,0 +1,107 @@ +// Copyright (c) 2019 Google LLC +// +// 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 SOURCE_OPT_CODE_SINK_H_ +#define SOURCE_OPT_CODE_SINK_H_ + +#include <unordered_map> + +#include "source/opt/ir_context.h" +#include "source/opt/module.h" +#include "source/opt/pass.h" + +namespace spvtools { +namespace opt { + +// This pass does code sinking for OpAccessChain and OpLoad on variables in +// uniform storage or in read only memory. Code sinking is a transformation +// where an instruction is moved into a more deeply nested construct. +// +// The goal is to move these instructions as close as possible to their uses +// without having to execute them more often or to replicate the instruction. +// Moving the instruction in this way can lead to shorter live ranges, which can +// lead to less register pressure. It can also cause instructions to be +// executed less often because they could be moved into one path of a selection +// construct. +// +// This optimization can cause register pressure to rise if the operands of the +// instructions go dead after the instructions being moved. That is why we only +// move certain OpLoad and OpAccessChain instructions. They generally have +// constants, loop induction variables, and global pointers as operands. The +// operands are live for a longer time in most cases. +class CodeSinkingPass : public Pass { + public: + const char* name() const override { return "code-sink"; } + Status Process() override; + + // Return the mask of preserved Analyses. + IRContext::Analysis GetPreservedAnalyses() override { + return IRContext::kAnalysisDefUse | + IRContext::kAnalysisInstrToBlockMapping | + IRContext::kAnalysisCombinators | IRContext::kAnalysisCFG | + IRContext::kAnalysisDominatorAnalysis | + IRContext::kAnalysisLoopAnalysis | IRContext::kAnalysisNameMap | + IRContext::kAnalysisConstants | IRContext::kAnalysisTypes; + } + + private: + // Sinks the instructions in |bb| as much as possible. Returns true if + // something changes. + bool SinkInstructionsInBB(BasicBlock* bb); + + // Tries the sink |inst| as much as possible. Returns true if the instruction + // is moved. + bool SinkInstruction(Instruction* inst); + + // Returns the basic block in which to move |inst| to move is as close as + // possible to the uses of |inst| without increasing the number of times + // |inst| will be executed. Return |nullptr| if there is no need to move + // |inst|. + BasicBlock* FindNewBasicBlockFor(Instruction* inst); + + // Return true if |inst| reference memory and it is possible that the data in + // the memory changes at some point. + bool ReferencesMutableMemory(Instruction* inst); + + // Returns true if the module contains an instruction that has a memory + // semantics id as an operand, and the memory semantics enforces a + // synchronization of uniform memory. See section 3.25 of the SPIR-V + // specification. + bool HasUniformMemorySync(); + + // Returns true if there may be a store to the variable |var_inst|. + bool HasPossibleStore(Instruction* var_inst); + + // Returns true if one of the basic blocks in |set| exists on a path from the + // basic block |start| to |end|. + bool IntersectsPath(uint32_t start, uint32_t end, + const std::unordered_set<uint32_t>& set); + + // Returns true if |mem_semantics_id| is the id of a constant that, when + // interpreted as a memory semantics mask enforces synchronization of uniform + // memory. See section 3.25 of the SPIR-V specification. + bool IsSyncOnUniform(uint32_t mem_semantics_id) const; + + // True if a check has for uniform storage has taken place. + bool checked_for_uniform_sync_; + + // Cache of whether or not the module has a memory sync on uniform storage. + // only valid if |check_for_uniform_sync_| is true. + bool has_uniform_sync_; +}; + +} // namespace opt +} // namespace spvtools + +#endif // SOURCE_OPT_CODE_SINK_H_ |