source/val/validate_adjacency.cpp

// Copyright (c) 2018 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.

// Validates correctness of the intra-block preconditions of SPIR-V
// instructions.

#include "source/val/validate.h"

#include <string>

#include "source/diagnostic.h"
#include "source/opcode.h"
#include "source/val/instruction.h"
#include "source/val/validation_state.h"

namespace spvtools {
namespace val {

spv_result_t ValidateAdjacency(ValidationState_t& _, size_t idx) {
  const auto& instructions = _.ordered_instructions();
  const auto& inst = instructions[idx];

  switch (inst.opcode()) {
    case SpvOpPhi:
      if (idx > 0) {
        switch (instructions[idx - 1].opcode()) {
          case SpvOpLabel:
          case SpvOpPhi:
          case SpvOpLine:
            break;
          default:
            return _.diag(SPV_ERROR_INVALID_DATA, &inst)
                   << "OpPhi must appear before all non-OpPhi instructions "
                   << "(except for OpLine, which can be mixed with OpPhi).";
        }
      }
      break;
    case SpvOpLoopMerge:
      if (idx != (instructions.size() - 1)) {
        switch (instructions[idx + 1].opcode()) {
          case SpvOpBranch:
          case SpvOpBranchConditional:
            break;
          default:
            return _.diag(SPV_ERROR_INVALID_DATA, &inst)
                   << "OpLoopMerge must immediately precede either an "
                   << "OpBranch or OpBranchConditional instruction. "
                   << "OpLoopMerge must be the second-to-last instruction in "
                   << "its block.";
        }
      }
      break;
    case SpvOpSelectionMerge:
      if (idx != (instructions.size() - 1)) {
        switch (instructions[idx + 1].opcode()) {
          case SpvOpBranchConditional:
          case SpvOpSwitch:
            break;
          default:
            return _.diag(SPV_ERROR_INVALID_DATA, &inst)
                   << "OpSelectionMerge must immediately precede either an "
                   << "OpBranchConditional or OpSwitch instruction. "
                   << "OpSelectionMerge must be the second-to-last "
                   << "instruction in its block.";
        }
      }
    default:
      break;
  }

  return SPV_SUCCESS;
}

}  // namespace val
}  // namespace spvtools