1// Copyright (c) 2018 LunarG 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 correctness of the intra-block preconditions of SPIR-V
16// instructions.
17
18#include "source/val/validate.h"
19
20#include <string>
21
22#include "source/diagnostic.h"
23#include "source/opcode.h"
24#include "source/val/instruction.h"
25#include "source/val/validation_state.h"
26
27namespace spvtools {
28namespace val {
29
30enum {
31 // Status right after meeting OpFunction.
32 IN_NEW_FUNCTION,
33 // Status right after meeting the entry block.
34 IN_ENTRY_BLOCK,
35 // Status right after meeting non-entry blocks.
36 PHI_VALID,
37 // Status right after meeting non-OpVariable instructions in the entry block
38 // or non-OpPhi instructions in non-entry blocks, except OpLine.
39 PHI_AND_VAR_INVALID,
40};
41
42spv_result_t ValidateAdjacency(ValidationState_t& _) {
43 const auto& instructions = _.ordered_instructions();
44 int adjacency_status = PHI_AND_VAR_INVALID;
45
46 for (size_t i = 0; i < instructions.size(); ++i) {
47 const auto& inst = instructions[i];
48 switch (inst.opcode()) {
49 case SpvOpFunction:
50 case SpvOpFunctionParameter:
51 adjacency_status = IN_NEW_FUNCTION;
52 break;
53 case SpvOpLabel:
54 adjacency_status =
55 adjacency_status == IN_NEW_FUNCTION ? IN_ENTRY_BLOCK : PHI_VALID;
56 break;
57 case SpvOpExtInst:
58 // If it is a debug info instruction, we do not change the status to
59 // allow debug info instructions before OpVariable in a function.
60 // TODO(https://gitlab.khronos.org/spirv/SPIR-V/issues/533): We need
61 // to discuss the location of DebugScope, DebugNoScope, DebugDeclare,
62 // and DebugValue.
63 if (!spvExtInstIsDebugInfo(inst.ext_inst_type())) {
64 adjacency_status = PHI_AND_VAR_INVALID;
65 }
66 break;
67 case SpvOpPhi:
68 if (adjacency_status != PHI_VALID) {
69 return _.diag(SPV_ERROR_INVALID_DATA, &inst)
70 << "OpPhi must appear within a non-entry block before all "
71 << "non-OpPhi instructions "
72 << "(except for OpLine, which can be mixed with OpPhi).";
73 }
74 break;
75 case SpvOpLine:
76 case SpvOpNoLine:
77 break;
78 case SpvOpLoopMerge:
79 adjacency_status = PHI_AND_VAR_INVALID;
80 if (i != (instructions.size() - 1)) {
81 switch (instructions[i + 1].opcode()) {
82 case SpvOpBranch:
83 case SpvOpBranchConditional:
84 break;
85 default:
86 return _.diag(SPV_ERROR_INVALID_DATA, &inst)
87 << "OpLoopMerge must immediately precede either an "
88 << "OpBranch or OpBranchConditional instruction. "
89 << "OpLoopMerge must be the second-to-last instruction in "
90 << "its block.";
91 }
92 }
93 break;
94 case SpvOpSelectionMerge:
95 adjacency_status = PHI_AND_VAR_INVALID;
96 if (i != (instructions.size() - 1)) {
97 switch (instructions[i + 1].opcode()) {
98 case SpvOpBranchConditional:
99 case SpvOpSwitch:
100 break;
101 default:
102 return _.diag(SPV_ERROR_INVALID_DATA, &inst)
103 << "OpSelectionMerge must immediately precede either an "
104 << "OpBranchConditional or OpSwitch instruction. "
105 << "OpSelectionMerge must be the second-to-last "
106 << "instruction in its block.";
107 }
108 }
109 break;
110 case SpvOpVariable:
111 if (inst.GetOperandAs<SpvStorageClass>(2) == SpvStorageClassFunction &&
112 adjacency_status != IN_ENTRY_BLOCK) {
113 return _.diag(SPV_ERROR_INVALID_DATA, &inst)
114 << "All OpVariable instructions in a function must be the "
115 "first instructions in the first block.";
116 }
117 break;
118 default:
119 adjacency_status = PHI_AND_VAR_INVALID;
120 break;
121 }
122 }
123
124 return SPV_SUCCESS;
125}
126
127} // namespace val
128} // namespace spvtools
129