| // Copyright (c) 2020 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_REDUCE_REMOVE_STRUCT_MEMBER_REDUCTION_OPPORTUNITY_H_ |
| #define SOURCE_REDUCE_REMOVE_STRUCT_MEMBER_REDUCTION_OPPORTUNITY_H_ |
| |
| #include "source/reduce/reduction_opportunity.h" |
| |
| #include "source/opt/instruction.h" |
| |
| namespace spvtools { |
| namespace reduce { |
| |
| // An opportunity for removing a member from a struct type, adjusting all uses |
| // of the struct accordingly. |
| class RemoveStructMemberReductionOpportunity : public ReductionOpportunity { |
| public: |
| // Constructs a reduction opportunity from the struct type |struct_type|, for |
| // removal of member |member_index|. |
| RemoveStructMemberReductionOpportunity(opt::Instruction* struct_type, |
| uint32_t member_index) |
| : struct_type_(struct_type), |
| member_index_(member_index), |
| original_number_of_members_(struct_type->NumInOperands()) {} |
| |
| // Opportunities to remove fields from a common struct type mutually |
| // invalidate each other. We guard against this by requiring that the struct |
| // still has the number of members it had when the opportunity was created. |
| bool PreconditionHolds() override; |
| |
| protected: |
| void Apply() override; |
| |
| private: |
| // |composite_access_instruction| is an instruction that accesses a composite |
| // id using either a series of literal indices (e.g. in the case of |
| // OpCompositeInsert) or a series of index ids (e.g. in the case of |
| // OpAccessChain). |
| // |
| // This function adjusts the indices that are used by |
| // |composite_access_instruction| to that whenever an index is accessing a |
| // member of |struct_type_|, it is decremented if the member is beyond |
| // |member_index_|, to account for the removal of the |member_index_|-th |
| // member. |
| // |
| // |composite_type_id| is the id of the composite type that the series of |
| // indices is to be applied to. |
| // |
| // |first_index_input_operand| specifies the first input operand that is an |
| // index. |
| // |
| // |literal_indices| specifies whether indices are given as literals (true), |
| // or as ids (false). |
| // |
| // If id-based indexing is used, this function will add a constant for |
| // |member_index_| - 1 to the module if needed. |
| void AdjustAccessedIndices( |
| uint32_t composite_type_id, uint32_t first_index_input_operand, |
| bool literal_indices, opt::IRContext* context, |
| opt::Instruction* composite_access_instruction) const; |
| |
| // The struct type from which a member is to be removed. |
| opt::Instruction* struct_type_; |
| |
| uint32_t member_index_; |
| |
| uint32_t original_number_of_members_; |
| }; |
| |
| } // namespace reduce |
| } // namespace spvtools |
| |
| #endif // SOURCE_REDUCE_REMOVE_STRUCT_MEMBER_REDUCTION_OPPORTUNITY_H_ |