1 // Copyright (c) 2017 Google Inc. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 // Validates literal numbers. 16 17 #include "source/val/validate.h" 18 19 #include <cassert> 20 21 #include "source/diagnostic.h" 22 #include "source/opcode.h" 23 #include "source/val/instruction.h" 24 #include "source/val/validation_state.h" 25 26 namespace spvtools { 27 namespace val { 28 namespace { 29 30 // Returns true if the operand holds a literal number 31 bool IsLiteralNumber(const spv_parsed_operand_t& operand) { 32 switch (operand.number_kind) { 33 case SPV_NUMBER_SIGNED_INT: 34 case SPV_NUMBER_UNSIGNED_INT: 35 case SPV_NUMBER_FLOATING: 36 return true; 37 default: 38 return false; 39 } 40 } 41 42 // Verifies that the upper bits of the given upper |word| with given 43 // lower |width| are zero- or sign-extended when |signed_int| is true 44 bool VerifyUpperBits(uint32_t word, uint32_t width, bool signed_int) { 45 assert(width < 32); 46 assert(0 < width); 47 const uint32_t upper_mask = 0xFFFFFFFFu << width; 48 const uint32_t upper_bits = word & upper_mask; 49 50 bool result = false; 51 if (signed_int) { 52 const uint32_t sign_bit = word & (1u << (width - 1)); 53 if (sign_bit) { 54 result = upper_bits == upper_mask; 55 } else { 56 result = upper_bits == 0; 57 } 58 } else { 59 result = upper_bits == 0; 60 } 61 return result; 62 } 63 64 } // namespace 65 66 // Validates that literal numbers are represented according to the spec 67 spv_result_t LiteralsPass(ValidationState_t& _, const Instruction* inst) { 68 // For every operand that is a literal number 69 for (size_t i = 0; i < inst->operands().size(); i++) { 70 const spv_parsed_operand_t& operand = inst->operand(i); 71 if (!IsLiteralNumber(operand)) continue; 72 73 // The upper bits are always in the last word (little-endian) 74 int last_index = operand.offset + operand.num_words - 1; 75 const uint32_t upper_word = inst->word(last_index); 76 77 // TODO(jcaraban): is the |word size| defined in some header? 78 const uint32_t word_size = 32; 79 uint32_t bit_width = operand.number_bit_width; 80 81 // Bit widths that are a multiple of the word size have no upper bits 82 const auto remaining_value_bits = bit_width % word_size; 83 if (remaining_value_bits == 0) continue; 84 85 const bool signedness = operand.number_kind == SPV_NUMBER_SIGNED_INT; 86 87 if (!VerifyUpperBits(upper_word, remaining_value_bits, signedness)) { 88 return _.diag(SPV_ERROR_INVALID_VALUE, inst) 89 << "The high-order bits of a literal number in instruction <id> " 90 << inst->id() << " must be 0 for a floating-point type, " 91 << "or 0 for an integer type with Signedness of 0, " 92 << "or sign extended when Signedness is 1"; 93 } 94 } 95 return SPV_SUCCESS; 96 } 97 98 } // namespace val 99 } // namespace spvtools 100
