xref: /aosp_15_r20/external/angle/third_party/spirv-tools/src/source/val/validate_literals.cpp (revision 8975f5c5ed3d1c378011245431ada316dfb6f244)
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 <cassert>
18 
19 #include "source/val/instruction.h"
20 #include "source/val/validate.h"
21 #include "source/val/validation_state.h"
22 
23 namespace spvtools {
24 namespace val {
25 namespace {
26 
27 // Returns true if the operand holds a literal number
IsLiteralNumber(const spv_parsed_operand_t & operand)28 bool IsLiteralNumber(const spv_parsed_operand_t& operand) {
29   switch (operand.number_kind) {
30     case SPV_NUMBER_SIGNED_INT:
31     case SPV_NUMBER_UNSIGNED_INT:
32     case SPV_NUMBER_FLOATING:
33       return true;
34     default:
35       return false;
36   }
37 }
38 
39 // Verifies that the upper bits of the given upper |word| with given
40 // lower |width| are zero- or sign-extended when |signed_int| is true
VerifyUpperBits(uint32_t word,uint32_t width,bool signed_int)41 bool VerifyUpperBits(uint32_t word, uint32_t width, bool signed_int) {
42   assert(width < 32);
43   assert(0 < width);
44   const uint32_t upper_mask = 0xFFFFFFFFu << width;
45   const uint32_t upper_bits = word & upper_mask;
46 
47   bool result = false;
48   if (signed_int) {
49     const uint32_t sign_bit = word & (1u << (width - 1));
50     if (sign_bit) {
51       result = upper_bits == upper_mask;
52     } else {
53       result = upper_bits == 0;
54     }
55   } else {
56     result = upper_bits == 0;
57   }
58   return result;
59 }
60 
61 }  // namespace
62 
63 // Validates that literal numbers are represented according to the spec
LiteralsPass(ValidationState_t & _,const Instruction * inst)64 spv_result_t LiteralsPass(ValidationState_t& _, const Instruction* inst) {
65   // For every operand that is a literal number
66   for (size_t i = 0; i < inst->operands().size(); i++) {
67     const spv_parsed_operand_t& operand = inst->operand(i);
68     if (!IsLiteralNumber(operand)) continue;
69 
70     // The upper bits are always in the last word (little-endian)
71     int last_index = operand.offset + operand.num_words - 1;
72     const uint32_t upper_word = inst->word(last_index);
73 
74     // TODO(jcaraban): is the |word size| defined in some header?
75     const uint32_t word_size = 32;
76     uint32_t bit_width = operand.number_bit_width;
77 
78     // Bit widths that are a multiple of the word size have no upper bits
79     const auto remaining_value_bits = bit_width % word_size;
80     if (remaining_value_bits == 0) continue;
81 
82     const bool signedness = operand.number_kind == SPV_NUMBER_SIGNED_INT;
83 
84     if (!VerifyUpperBits(upper_word, remaining_value_bits, signedness)) {
85       return _.diag(SPV_ERROR_INVALID_VALUE, inst)
86              << "The high-order bits of a literal number in instruction <id> "
87              << inst->id() << " must be 0 for a floating-point type, "
88              << "or 0 for an integer type with Signedness of 0, "
89              << "or sign extended when Signedness is 1";
90     }
91   }
92   return SPV_SUCCESS;
93 }
94 
95 }  // namespace val
96 }  // namespace spvtools
97