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// 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_DESC_SROA_H_
#define SOURCE_OPT_DESC_SROA_H_
#include <cstdio>
#include <memory>
#include <queue>
#include <unordered_map>
#include <unordered_set>
#include <vector>
#include "source/opt/function.h"
#include "source/opt/pass.h"
#include "source/opt/type_manager.h"
namespace spvtools {
namespace opt {
// Documented in optimizer.hpp
class DescriptorScalarReplacement : public Pass {
public:
DescriptorScalarReplacement() {}
const char* name() const override { return "descriptor-scalar-replacement"; }
Status Process() override;
IRContext::Analysis GetPreservedAnalyses() override {
return IRContext::kAnalysisDefUse |
IRContext::kAnalysisInstrToBlockMapping |
IRContext::kAnalysisCombinators | IRContext::kAnalysisCFG |
IRContext::kAnalysisConstants | IRContext::kAnalysisTypes;
}
private:
// Replaces all references to |var| by new variables, one for each element of
// the array |var|. The binding for the new variables corresponding to
// element i will be the binding of |var| plus i. Returns true if successful.
bool ReplaceCandidate(Instruction* var);
// Replaces the base address |var| in the OpAccessChain or
// OpInBoundsAccessChain instruction |use| by the variable that the access
// chain accesses. The first index in |use| must be an |OpConstant|. Returns
// |true| if successful.
bool ReplaceAccessChain(Instruction* var, Instruction* use);
// Replaces the given compososite variable |var| loaded by OpLoad |value| with
// replacement variables, one for each component that's accessed in the
// shader. Assumes that |value| is only used by OpCompositeExtract
// instructions, one index at a time. Returns true on success, and false
// otherwise.
bool ReplaceLoadedValue(Instruction* var, Instruction* value);
// Replaces the given OpCompositeExtract |extract| and all of its references
// with an OpLoad of a replacement variable. |var| is the variable with
// composite type whose value is being used by |extract|. Assumes that
// |extract| is extracting one index only. Returns true on success, and false
// otherwise.
bool ReplaceCompositeExtract(Instruction* var, Instruction* extract);
// Returns the id of the variable that will be used to replace the |idx|th
// element of |var|. The variable is created if it has not already been
// created.
uint32_t GetReplacementVariable(Instruction* var, uint32_t idx);
// Returns the id of a new variable that can be used to replace the |idx|th
// element of |var|.
uint32_t CreateReplacementVariable(Instruction* var, uint32_t idx);
// Returns the number of bindings used by the given |type_id|.
// All types are considered to use 1 binding slot, except:
// 1- A pointer type consumes as many binding numbers as its pointee.
// 2- An array of size N consumes N*M binding numbers, where M is the number
// of bindings used by each array element.
// 3- The number of bindings consumed by a structure is the sum of the
// bindings used by its members.
uint32_t GetNumBindingsUsedByType(uint32_t type_id);
// Copy all of the decorations of variable |old_var| and make them as
// decorations for the new variable whose id is |new_var_id|. The new variable
// is supposed to replace |index|th element of |old_var|.
// |new_var_ptr_type_id| is the id of the pointer to the type of the new
// variable. |is_old_var_array| is true if |old_var| has an array type.
// |is_old_var_struct| is true if |old_var| has a structure type.
// |old_var_type| is the pointee type of |old_var|.
void CopyDecorationsForNewVariable(Instruction* old_var, uint32_t index,
uint32_t new_var_id,
uint32_t new_var_ptr_type_id,
const bool is_old_var_array,
const bool is_old_var_struct,
Instruction* old_var_type);
// Get the new binding number for a new variable that will be replaced with an
// |index|th element of an old variable. The old variable has |old_binding|
// as its binding number. |ptr_elem_type_id| the id of the pointer to the
// element type. |is_old_var_array| is true if the old variable has an array
// type. |is_old_var_struct| is true if the old variable has a structure type.
// |old_var_type| is the pointee type of the old variable.
uint32_t GetNewBindingForElement(uint32_t old_binding, uint32_t index,
uint32_t ptr_elem_type_id,
const bool is_old_var_array,
const bool is_old_var_struct,
Instruction* old_var_type);
// Create a new OpDecorate(String) instruction by cloning |old_decoration|.
// The new OpDecorate(String) instruction will be used for a variable whose id
// is |new_var_ptr_type_id|. If |old_decoration| is a decoration for a
// binding, the new OpDecorate(String) instruction will have |new_binding| as
// its binding.
void CreateNewDecorationForNewVariable(Instruction* old_decoration,
uint32_t new_var_id,
uint32_t new_binding);
// Create a new OpDecorate instruction whose operand is the same as an
// OpMemberDecorate instruction |old_member_decoration| except Target operand.
// The Target operand of the new OpDecorate instruction will be |new_var_id|.
void CreateNewDecorationForMemberDecorate(Instruction* old_decoration,
uint32_t new_var_id);
// A map from an OpVariable instruction to the set of variables that will be
// used to replace it. The entry |replacement_variables_[var][i]| is the id of
// a variable that will be used in the place of the ith element of the
// array |var|. If the entry is |0|, then the variable has not been
// created yet.
std::map<Instruction*, std::vector<uint32_t>> replacement_variables_;
};
} // namespace opt
} // namespace spvtools
#endif // SOURCE_OPT_DESC_SROA_H_