| // Copyright (c) 2017 Google 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 SOURCE_OPT_FOLD_H_ |
| #define SOURCE_OPT_FOLD_H_ |
| |
| #include <cstdint> |
| #include <vector> |
| |
| #include "source/opt/const_folding_rules.h" |
| #include "source/opt/constants.h" |
| #include "source/opt/def_use_manager.h" |
| #include "source/opt/folding_rules.h" |
| |
| namespace spvtools { |
| namespace opt { |
| |
| class InstructionFolder { |
| public: |
| explicit InstructionFolder(IRContext* context) |
| : context_(context), |
| const_folding_rules_(new ConstantFoldingRules(context)), |
| folding_rules_(new FoldingRules(context)) { |
| folding_rules_->AddFoldingRules(); |
| const_folding_rules_->AddFoldingRules(); |
| } |
| |
| explicit InstructionFolder( |
| IRContext* context, std::unique_ptr<FoldingRules>&& folding_rules, |
| std::unique_ptr<ConstantFoldingRules>&& constant_folding_rules) |
| : context_(context), |
| const_folding_rules_(std::move(constant_folding_rules)), |
| folding_rules_(std::move(folding_rules)) { |
| folding_rules_->AddFoldingRules(); |
| const_folding_rules_->AddFoldingRules(); |
| } |
| |
| // Returns the result of folding a scalar instruction with the given |opcode| |
| // and |operands|. Each entry in |operands| is a pointer to an |
| // analysis::Constant instance, which should've been created with the constant |
| // manager (See IRContext::get_constant_mgr). |
| // |
| // It is an error to call this function with an opcode that does not pass the |
| // IsFoldableOpcode test. If any error occurs during folding, the folder will |
| // fail with a call to assert. |
| uint32_t FoldScalars( |
| spv::Op opcode, |
| const std::vector<const analysis::Constant*>& operands) const; |
| |
| // Returns the result of performing an operation with the given |opcode| over |
| // constant vectors with |num_dims| dimensions. Each entry in |operands| is a |
| // pointer to an analysis::Constant instance, which should've been created |
| // with the constant manager (See IRContext::get_constant_mgr). |
| // |
| // This function iterates through the given vector type constant operands and |
| // calculates the result for each element of the result vector to return. |
| // Vectors with longer than 32-bit scalar components are not accepted in this |
| // function. |
| // |
| // It is an error to call this function with an opcode that does not pass the |
| // IsFoldableOpcode test. If any error occurs during folding, the folder will |
| // fail with a call to assert. |
| std::vector<uint32_t> FoldVectors( |
| spv::Op opcode, uint32_t num_dims, |
| const std::vector<const analysis::Constant*>& operands) const; |
| |
| // Returns true if |opcode| represents an operation handled by FoldScalars or |
| // FoldVectors. |
| bool IsFoldableOpcode(spv::Op opcode) const; |
| |
| // Returns true if |cst| is supported by FoldScalars and FoldVectors. |
| bool IsFoldableConstant(const analysis::Constant* cst) const; |
| |
| // Returns true if |FoldInstructionToConstant| could fold an instruction whose |
| // result type is |type_inst|. |
| bool IsFoldableType(Instruction* type_inst) const; |
| |
| // Returns true if |FoldInstructionToConstant| could fold an instruction whose |
| // result type is |type_inst|. |
| bool IsFoldableScalarType(Instruction* type_inst) const; |
| |
| // Returns true if |FoldInstructionToConstant| could fold an instruction whose |
| // result type is |type_inst|. |
| bool IsFoldableVectorType(Instruction* type_inst) const; |
| |
| // Tries to fold |inst| to a single constant, when the input ids to |inst| |
| // have been substituted using |id_map|. Returns a pointer to the OpConstant* |
| // instruction if successful. If necessary, a new constant instruction is |
| // created and placed in the global values section. |
| // |
| // |id_map| is a function that takes one result id and returns another. It |
| // can be used for things like CCP where it is known that some ids contain a |
| // constant, but the instruction itself has not been updated yet. This can |
| // map those ids to the appropriate constants. |
| Instruction* FoldInstructionToConstant( |
| Instruction* inst, std::function<uint32_t(uint32_t)> id_map) const; |
| // Returns true if |inst| can be folded into a simpler instruction. |
| // If |inst| can be simplified, |inst| is overwritten with the simplified |
| // instruction reusing the same result id. |
| // |
| // If |inst| is simplified, it is possible that the resulting code in invalid |
| // because the instruction is in a bad location. Callers of this function |
| // have to handle the following cases: |
| // |
| // 1) An OpPhi becomes and OpCopyObject - If there are OpPhi instruction after |
| // |inst| in a basic block then this is invalid. The caller must fix this |
| // up. |
| bool FoldInstruction(Instruction* inst) const; |
| |
| // Return true if this opcode has a const folding rule associtated with it. |
| bool HasConstFoldingRule(const Instruction* inst) const { |
| return GetConstantFoldingRules().HasFoldingRule(inst); |
| } |
| |
| private: |
| // Returns a reference to the ConstnatFoldingRules instance. |
| const ConstantFoldingRules& GetConstantFoldingRules() const { |
| return *const_folding_rules_; |
| } |
| |
| // Returns a reference to the FoldingRules instance. |
| const FoldingRules& GetFoldingRules() const { return *folding_rules_; } |
| |
| // Returns the single-word result from performing the given unary operation on |
| // the operand value which is passed in as a 32-bit word. |
| uint32_t UnaryOperate(spv::Op opcode, uint32_t operand) const; |
| |
| // Returns the single-word result from performing the given binary operation |
| // on the operand values which are passed in as two 32-bit word. |
| uint32_t BinaryOperate(spv::Op opcode, uint32_t a, uint32_t b) const; |
| |
| // Returns the single-word result from performing the given ternary operation |
| // on the operand values which are passed in as three 32-bit word. |
| uint32_t TernaryOperate(spv::Op opcode, uint32_t a, uint32_t b, |
| uint32_t c) const; |
| |
| // Returns the single-word result from performing the given operation on the |
| // operand words. This only works with 32-bit operations and uses boolean |
| // convention that 0u is false, and anything else is boolean true. |
| // TODO(qining): Support operands other than 32-bit wide. |
| uint32_t OperateWords(spv::Op opcode, |
| const std::vector<uint32_t>& operand_words) const; |
| |
| bool FoldInstructionInternal(Instruction* inst) const; |
| |
| // Returns true if |inst| is a binary operation that takes two integers as |
| // parameters and folds to a constant that can be represented as an unsigned |
| // 32-bit value when the ids have been replaced by |id_map|. If |inst| can be |
| // folded, the resulting value is returned in |*result|. Valid result types |
| // for the instruction are any integer (signed or unsigned) with 32-bits or |
| // less, or a boolean value. |
| bool FoldBinaryIntegerOpToConstant( |
| Instruction* inst, const std::function<uint32_t(uint32_t)>& id_map, |
| uint32_t* result) const; |
| |
| // Returns true if |inst| is a binary operation on two boolean values, and |
| // folds |
| // to a constant boolean value when the ids have been replaced using |id_map|. |
| // If |inst| can be folded, the result value is returned in |*result|. |
| bool FoldBinaryBooleanOpToConstant( |
| Instruction* inst, const std::function<uint32_t(uint32_t)>& id_map, |
| uint32_t* result) const; |
| |
| // Returns true if |inst| can be folded to an constant when the ids have been |
| // substituted using id_map. If it can, the value is returned in |result|. If |
| // not, |result| is unchanged. It is assumed that not all operands are |
| // constant. Those cases are handled by |FoldScalar|. |
| bool FoldIntegerOpToConstant(Instruction* inst, |
| const std::function<uint32_t(uint32_t)>& id_map, |
| uint32_t* result) const; |
| |
| IRContext* context_; |
| |
| // Folding rules used by |FoldInstructionToConstant| and |FoldInstruction|. |
| std::unique_ptr<ConstantFoldingRules> const_folding_rules_; |
| |
| // Folding rules used by |FoldInstruction|. |
| std::unique_ptr<FoldingRules> folding_rules_; |
| }; |
| |
| } // namespace opt |
| } // namespace spvtools |
| |
| #endif // SOURCE_OPT_FOLD_H_ |