1 // Copyright (c) 2021 Google LLC
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 #include "source/opt/desc_sroa_util.h"
16
17 namespace spvtools {
18 namespace opt {
19 namespace {
20 constexpr uint32_t kOpAccessChainInOperandIndexes = 1;
21
22 // Returns the length of array type |type|.
GetLengthOfArrayType(IRContext * context,Instruction * type)23 uint32_t GetLengthOfArrayType(IRContext* context, Instruction* type) {
24 assert(type->opcode() == spv::Op::OpTypeArray && "type must be array");
25 uint32_t length_id = type->GetSingleWordInOperand(1);
26 const analysis::Constant* length_const =
27 context->get_constant_mgr()->FindDeclaredConstant(length_id);
28 assert(length_const != nullptr);
29 return length_const->GetU32();
30 }
31
HasDescriptorDecorations(IRContext * context,Instruction * var)32 bool HasDescriptorDecorations(IRContext* context, Instruction* var) {
33 const auto& decoration_mgr = context->get_decoration_mgr();
34 return decoration_mgr->HasDecoration(
35 var->result_id(), uint32_t(spv::Decoration::DescriptorSet)) &&
36 decoration_mgr->HasDecoration(var->result_id(),
37 uint32_t(spv::Decoration::Binding));
38 }
39
GetVariableType(IRContext * context,Instruction * var)40 Instruction* GetVariableType(IRContext* context, Instruction* var) {
41 if (var->opcode() != spv::Op::OpVariable) {
42 return nullptr;
43 }
44
45 uint32_t ptr_type_id = var->type_id();
46 Instruction* ptr_type_inst = context->get_def_use_mgr()->GetDef(ptr_type_id);
47 if (ptr_type_inst->opcode() != spv::Op::OpTypePointer) {
48 return nullptr;
49 }
50
51 uint32_t var_type_id = ptr_type_inst->GetSingleWordInOperand(1);
52 return context->get_def_use_mgr()->GetDef(var_type_id);
53 }
54
55 } // namespace
56
57 namespace descsroautil {
58
IsDescriptorArray(IRContext * context,Instruction * var)59 bool IsDescriptorArray(IRContext* context, Instruction* var) {
60 Instruction* var_type_inst = GetVariableType(context, var);
61 if (var_type_inst == nullptr) return false;
62 return var_type_inst->opcode() == spv::Op::OpTypeArray &&
63 HasDescriptorDecorations(context, var);
64 }
65
IsDescriptorStruct(IRContext * context,Instruction * var)66 bool IsDescriptorStruct(IRContext* context, Instruction* var) {
67 Instruction* var_type_inst = GetVariableType(context, var);
68 if (var_type_inst == nullptr) return false;
69
70 while (var_type_inst->opcode() == spv::Op::OpTypeArray) {
71 var_type_inst = context->get_def_use_mgr()->GetDef(
72 var_type_inst->GetInOperand(0).AsId());
73 }
74
75 if (var_type_inst->opcode() != spv::Op::OpTypeStruct) return false;
76
77 // All structures with descriptor assignments must be replaced by variables,
78 // one for each of their members - with the exceptions of buffers.
79 if (IsTypeOfStructuredBuffer(context, var_type_inst)) {
80 return false;
81 }
82
83 return HasDescriptorDecorations(context, var);
84 }
85
IsTypeOfStructuredBuffer(IRContext * context,const Instruction * type)86 bool IsTypeOfStructuredBuffer(IRContext* context, const Instruction* type) {
87 if (type->opcode() != spv::Op::OpTypeStruct) {
88 return false;
89 }
90
91 // All buffers have offset decorations for members of their structure types.
92 // This is how we distinguish it from a structure of descriptors.
93 return context->get_decoration_mgr()->HasDecoration(
94 type->result_id(), uint32_t(spv::Decoration::Offset));
95 }
96
GetAccessChainIndexAsConst(IRContext * context,Instruction * access_chain)97 const analysis::Constant* GetAccessChainIndexAsConst(
98 IRContext* context, Instruction* access_chain) {
99 if (access_chain->NumInOperands() <= 1) {
100 return nullptr;
101 }
102 uint32_t idx_id = GetFirstIndexOfAccessChain(access_chain);
103 const analysis::Constant* idx_const =
104 context->get_constant_mgr()->FindDeclaredConstant(idx_id);
105 return idx_const;
106 }
107
GetFirstIndexOfAccessChain(Instruction * access_chain)108 uint32_t GetFirstIndexOfAccessChain(Instruction* access_chain) {
109 assert(access_chain->NumInOperands() > 1 &&
110 "OpAccessChain does not have Indexes operand");
111 return access_chain->GetSingleWordInOperand(kOpAccessChainInOperandIndexes);
112 }
113
GetNumberOfElementsForArrayOrStruct(IRContext * context,Instruction * var)114 uint32_t GetNumberOfElementsForArrayOrStruct(IRContext* context,
115 Instruction* var) {
116 uint32_t ptr_type_id = var->type_id();
117 Instruction* ptr_type_inst = context->get_def_use_mgr()->GetDef(ptr_type_id);
118 assert(ptr_type_inst->opcode() == spv::Op::OpTypePointer &&
119 "Variable should be a pointer to an array or structure.");
120 uint32_t pointee_type_id = ptr_type_inst->GetSingleWordInOperand(1);
121 Instruction* pointee_type_inst =
122 context->get_def_use_mgr()->GetDef(pointee_type_id);
123 if (pointee_type_inst->opcode() == spv::Op::OpTypeArray) {
124 return GetLengthOfArrayType(context, pointee_type_inst);
125 }
126 assert(pointee_type_inst->opcode() == spv::Op::OpTypeStruct &&
127 "Variable should be a pointer to an array or structure.");
128 return pointee_type_inst->NumInOperands();
129 }
130
131 } // namespace descsroautil
132 } // namespace opt
133 } // namespace spvtools
134