text: // Copyright (c) 2015-2016 The Khronos Group 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_ASSEMBLY_GRAMMAR_H_
  #define LIBSPIRV_ASSEMBLY_GRAMMAR_H_
  
  #include "operand.h"
  #include "spirv-tools/libspirv.h"
  #include "spirv/1.2/spirv.h"
  #include "table.h"
  
  namespace libspirv {
  
  // Encapsulates the grammar to use for SPIR-V assembly.
  // Contains methods to query for valid instructions and operands.
  class AssemblyGrammar {
   public:
    explicit AssemblyGrammar(const spv_const_context context)
        : target_env_(context->target_env),
          operandTable_(context->operand_table),
          opcodeTable_(context->opcode_table),
          extInstTable_(context->ext_inst_table) {}
  
    // Returns true if the internal tables have been initialized with valid data.
    bool isValid() const;
  
    // Returns the SPIR-V target environment.
    spv_target_env target_env() const { return target_env_; }
  
    // Fills in the desc parameter with the information about the opcode
    // of the given name. Returns SPV_SUCCESS if the opcode was found, and
    // SPV_ERROR_INVALID_LOOKUP if the opcode does not exist.
    spv_result_t lookupOpcode(const char* name, spv_opcode_desc* desc) const;
  
    // Fills in the desc parameter with the information about the opcode
    // of the valid. Returns SPV_SUCCESS if the opcode was found, and
    // SPV_ERROR_INVALID_LOOKUP if the opcode does not exist.
    spv_result_t lookupOpcode(SpvOp opcode, spv_opcode_desc* desc) const;
  
    // Fills in the desc parameter with the information about the given
    // operand. Returns SPV_SUCCESS if the operand was found, and
    // SPV_ERROR_INVALID_LOOKUP otherwise.
    spv_result_t lookupOperand(spv_operand_type_t type, const char* name,
                               size_t name_len, spv_operand_desc* desc) const;
  
    // Fills in the desc parameter with the information about the given
    // operand. Returns SPV_SUCCESS if the operand was found, and
    // SPV_ERROR_INVALID_LOOKUP otherwise.
    spv_result_t lookupOperand(spv_operand_type_t type, uint32_t operand,
                               spv_operand_desc* desc) const;
  
    // Finds the opcode for the given OpSpecConstantOp opcode name. The name
    // should not have the "Op" prefix.  For example, "IAdd" corresponds to
    // the integer add opcode for OpSpecConstantOp.  On success, returns
    // SPV_SUCCESS and sends the discovered operation code through the opcode
    // parameter.  On failure, returns SPV_ERROR_INVALID_LOOKUP.
    spv_result_t lookupSpecConstantOpcode(const char* name, SpvOp* opcode) const;
  
    // Returns SPV_SUCCESS if the given opcode is valid as the opcode operand
    // to OpSpecConstantOp.
    spv_result_t lookupSpecConstantOpcode(SpvOp opcode) const;
  
    // Parses a mask expression string for the given operand type.
    //
    // A mask expression is a sequence of one or more terms separated by '|',
    // where each term is a named enum value for a given type. No whitespace
    // is permitted.
    //
    // On success, the value is written to pValue, and SPV_SUCCESS is returned.
    // The operand type is defined by the type parameter, and the text to be
    // parsed is defined by the textValue parameter.
    spv_result_t parseMaskOperand(const spv_operand_type_t type,
                                  const char* textValue, uint32_t* pValue) const;
  
    // Writes the extended operand with the given type and text to the *extInst
    // parameter.
    // Returns SPV_SUCCESS if the value could be found.
    spv_result_t lookupExtInst(spv_ext_inst_type_t type, const char* textValue,
                               spv_ext_inst_desc* extInst) const;
  
    // Writes the extended operand with the given type and first encoded word
    // to the *extInst parameter.
    // Returns SPV_SUCCESS if the value could be found.
    spv_result_t lookupExtInst(spv_ext_inst_type_t type, uint32_t firstWord,
                               spv_ext_inst_desc* extInst) const;
  
    // Inserts the operands expected after the given typed mask onto the end
    // of the given pattern.
    //
    // Each set bit in the mask represents zero or more operand types that
    // should be appended onto the pattern. Operands for a less significant
    // bit must always match before operands for a more significant bit, so
    // the operands for a less significant bit must appear closer to the end
    // of the pattern stack.
    //
    // If a set bit is unknown, then we assume it has no operands.
    void pushOperandTypesForMask(const spv_operand_type_t type,
                                 const uint32_t mask,
                                 spv_operand_pattern_t* pattern) const;
  
   private:
    const spv_target_env target_env_;
    const spv_operand_table operandTable_;
    const spv_opcode_table opcodeTable_;
    const spv_ext_inst_table extInstTable_;
  };
  }
  
  #endif  // LIBSPIRV_ASSEMBLY_GRAMMAR_H_
  