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// 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.
// Validates literal numbers.
#include <cassert>
#include "source/val/instruction.h"
#include "source/val/validate.h"
#include "source/val/validation_state.h"
namespace spvtools {
namespace val {
namespace {
// Returns true if the operand holds a literal number
bool IsLiteralNumber(const spv_parsed_operand_t& operand) {
switch (operand.number_kind) {
case SPV_NUMBER_SIGNED_INT:
case SPV_NUMBER_UNSIGNED_INT:
case SPV_NUMBER_FLOATING:
return true;
default:
return false;
}
}
// Verifies that the upper bits of the given upper |word| with given
// lower |width| are zero- or sign-extended when |signed_int| is true
bool VerifyUpperBits(uint32_t word, uint32_t width, bool signed_int) {
assert(width < 32);
assert(0 < width);
const uint32_t upper_mask = 0xFFFFFFFFu << width;
const uint32_t upper_bits = word & upper_mask;
bool result = false;
if (signed_int) {
const uint32_t sign_bit = word & (1u << (width - 1));
if (sign_bit) {
result = upper_bits == upper_mask;
} else {
result = upper_bits == 0;
}
} else {
result = upper_bits == 0;
}
return result;
}
} // namespace
// Validates that literal numbers are represented according to the spec
spv_result_t LiteralsPass(ValidationState_t& _, const Instruction* inst) {
// For every operand that is a literal number
for (size_t i = 0; i < inst->operands().size(); i++) {
const spv_parsed_operand_t& operand = inst->operand(i);
if (!IsLiteralNumber(operand)) continue;
// The upper bits are always in the last word (little-endian)
int last_index = operand.offset + operand.num_words - 1;
const uint32_t upper_word = inst->word(last_index);
// TODO(jcaraban): is the |word size| defined in some header?
const uint32_t word_size = 32;
uint32_t bit_width = operand.number_bit_width;
// Bit widths that are a multiple of the word size have no upper bits
const auto remaining_value_bits = bit_width % word_size;
if (remaining_value_bits == 0) continue;
const bool signedness = operand.number_kind == SPV_NUMBER_SIGNED_INT;
if (!VerifyUpperBits(upper_word, remaining_value_bits, signedness)) {
return _.diag(SPV_ERROR_INVALID_VALUE, inst)
<< "The high-order bits of a literal number in instruction <id> "
<< inst->id() << " must be 0 for a floating-point type, "
<< "or 0 for an integer type with Signedness of 0, "
<< "or sign extended when Signedness is 1";
}
}
return SPV_SUCCESS;
}
} // namespace val
} // namespace spvtools
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