SPIRV-Tools/source/opt/common_uniform_elim_pass.h

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// Copyright (c) 2016 The Khronos Group Inc.
// Copyright (c) 2016 Valve Corporation
// Copyright (c) 2016 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_COMMON_UNIFORM_ELIM_PASS_H_
#define LIBSPIRV_OPT_COMMON_UNIFORM_ELIM_PASS_H_
#include <algorithm>
#include <map>
#include <queue>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include "basic_block.h"
#include "decoration_manager.h"
#include "def_use_manager.h"
#include "ir_context.h"
#include "module.h"
#include "pass.h"
namespace spvtools {
namespace opt {
// See optimizer.hpp for documentation.
class CommonUniformElimPass : public Pass {
using cbb_ptr = const ir::BasicBlock*;
public:
using GetBlocksFunction =
std::function<std::vector<ir::BasicBlock*>*(const ir::BasicBlock*)>;
CommonUniformElimPass();
const char* name() const override { return "eliminate-common-uniform"; }
Status Process(ir::IRContext*) override;
private:
// Returns true if |opcode| is a non-ptr access chain op
bool IsNonPtrAccessChain(const SpvOp opcode) const;
// Returns true if |typeInst| is a sampler or image type or a struct
// containing one, recursively.
bool IsSamplerOrImageType(const ir::Instruction* typeInst) const;
// Returns true if |varId| is a variable containing a sampler or image.
bool IsSamplerOrImageVar(uint32_t varId) const;
// Given a load or store pointed at by |ip|, return the top-most
// non-CopyObj in its pointer operand. Also return the base pointer
// in |objId|.
ir::Instruction* GetPtr(ir::Instruction* ip, uint32_t* objId);
// Return true if variable is uniform
bool IsUniformVar(uint32_t varId);
// Given the type id for a struct type, checks if the struct type
// or any struct member is volatile decorated
bool IsVolatileStruct(uint32_t type_id);
// Given an OpAccessChain instruction, return true
// if the accessed variable belongs to a volatile
// decorated object or member of a struct type
bool IsAccessChainToVolatileStructType(
const ir::Instruction& AccessChainInst);
// Given an OpLoad instruction, return true if
// OpLoad has a Volatile Memory Access flag or if
// the resulting type is a volatile decorated struct
bool IsVolatileLoad(const ir::Instruction& loadInst);
// Return true if any uses of |id| are decorate ops.
bool HasUnsupportedDecorates(uint32_t id) const;
// Return true if all uses of |id| are only name or decorate ops.
bool HasOnlyNamesAndDecorates(uint32_t id) const;
// Delete inst if it has no uses. Assumes inst has a resultId.
void DeleteIfUseless(ir::Instruction* inst);
// Replace all instances of load's id with replId and delete load
// and its access chain, if any
ir::Instruction* ReplaceAndDeleteLoad(ir::Instruction* loadInst,
uint32_t replId,
ir::Instruction* ptrInst);
// For the (constant index) access chain ptrInst, create an
// equivalent load and extract
void GenACLoadRepl(const ir::Instruction* ptrInst,
std::vector<std::unique_ptr<ir::Instruction>>* newInsts,
uint32_t* resultId);
// Return true if all indices are constant
bool IsConstantIndexAccessChain(ir::Instruction* acp);
// Convert all uniform access chain loads into load/extract.
bool UniformAccessChainConvert(ir::Function* func);
// Compute structured successors for function |func|.
// A block's structured successors are the blocks it branches to
// together with its declared merge block if it has one.
// When order matters, the merge block always appears first.
// This assures correct depth first search in the presence of early
// returns and kills. If the successor vector contain duplicates
// if the merge block, they are safely ignored by DFS.
//
// TODO(dnovillo): This pass computes structured successors slightly different
// than the implementation in class Pass. Can this be re-factored?
void ComputeStructuredSuccessors(ir::Function* func);
// Compute structured block order for |func| into |structuredOrder|. This
// order has the property that dominators come before all blocks they
// dominate and merge blocks come after all blocks that are in the control
// constructs of their header.
//
// TODO(dnovillo): This pass computes structured order slightly different
// than the implementation in class Pass. Can this be re-factored?
void ComputeStructuredOrder(ir::Function* func,
std::list<ir::BasicBlock*>* order);
// Eliminate loads of uniform variables which have previously been loaded.
// If first load is in control flow, move it to first block of function.
// Most effective if preceded by UniformAccessChainRemoval().
bool CommonUniformLoadElimination(ir::Function* func);
// Eliminate loads of uniform sampler and image variables which have
// previously
// been loaded in the same block for types whose loads cannot cross blocks.
bool CommonUniformLoadElimBlock(ir::Function* func);
// Eliminate duplicated extracts of same id. Extract may be moved to same
// block as the id definition. This is primarily intended for extracts
// from uniform loads. Most effective if preceded by
// CommonUniformLoadElimination().
bool CommonExtractElimination(ir::Function* func);
// For function |func|, first change all uniform constant index
// access chain loads into equivalent composite extracts. Then consolidate
// identical uniform loads into one uniform load. Finally, consolidate
// identical uniform extracts into one uniform extract. This may require
// moving a load or extract to a point which dominates all uses.
// Return true if func is modified.
//
// This pass requires the function to have structured control flow ie shader
// capability. It also requires logical addressing ie Addresses capability
// is not enabled. It also currently does not support any extensions.
//
// This function currently only optimizes loads with a single index.
bool EliminateCommonUniform(ir::Function* func);
// Initialize extensions whitelist
void InitExtensions();
// Return true if all extensions in this module are allowed by this pass.
bool AllExtensionsSupported() const;
// Return true if |op| is a decorate for non-type instruction
inline bool IsNonTypeDecorate(uint32_t op) const {
return (op == SpvOpDecorate || op == SpvOpDecorateId);
}
void Initialize(ir::IRContext* c);
Pass::Status ProcessImpl();
// Map from uniform variable id to its common load id
std::unordered_map<uint32_t, uint32_t> uniform2load_id_;
// Map of extract composite ids to map of indices to insts
// TODO(greg-lunarg): Consider std::vector.
std::unordered_map<uint32_t,
std::unordered_map<uint32_t, std::list<ir::Instruction*>>>
comp2idx2inst_;
// Extensions supported by this pass.
std::unordered_set<std::string> extensions_whitelist_;
// Map from block to its structured successor blocks. See
// ComputeStructuredSuccessors() for definition.
std::unordered_map<const ir::BasicBlock*, std::vector<ir::BasicBlock*>>
block2structured_succs_;
};
} // namespace opt
} // namespace spvtools
#endif // LIBSPIRV_OPT_SSAMEM_PASS_H_