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
32 } // namespace
33
34 namespace descsroautil {
35
IsDescriptorArray(IRContext * context,Instruction * var)36 bool IsDescriptorArray(IRContext* context, Instruction* var) {
37 if (var->opcode() != spv::Op::OpVariable) {
38 return false;
39 }
40
41 uint32_t ptr_type_id = var->type_id();
42 Instruction* ptr_type_inst = context->get_def_use_mgr()->GetDef(ptr_type_id);
43 if (ptr_type_inst->opcode() != spv::Op::OpTypePointer) {
44 return false;
45 }
46
47 uint32_t var_type_id = ptr_type_inst->GetSingleWordInOperand(1);
48 Instruction* var_type_inst = context->get_def_use_mgr()->GetDef(var_type_id);
49 if (var_type_inst->opcode() != spv::Op::OpTypeArray &&
50 var_type_inst->opcode() != spv::Op::OpTypeStruct) {
51 return false;
52 }
53
54 // All structures with descriptor assignments must be replaced by variables,
55 // one for each of their members - with the exceptions of buffers.
56 if (IsTypeOfStructuredBuffer(context, var_type_inst)) {
57 return false;
58 }
59
60 if (!context->get_decoration_mgr()->HasDecoration(
61 var->result_id(), uint32_t(spv::Decoration::DescriptorSet))) {
62 return false;
63 }
64
65 return context->get_decoration_mgr()->HasDecoration(
66 var->result_id(), uint32_t(spv::Decoration::Binding));
67 }
68
IsTypeOfStructuredBuffer(IRContext * context,const Instruction * type)69 bool IsTypeOfStructuredBuffer(IRContext* context, const Instruction* type) {
70 if (type->opcode() != spv::Op::OpTypeStruct) {
71 return false;
72 }
73
74 // All buffers have offset decorations for members of their structure types.
75 // This is how we distinguish it from a structure of descriptors.
76 return context->get_decoration_mgr()->HasDecoration(
77 type->result_id(), uint32_t(spv::Decoration::Offset));
78 }
79
GetAccessChainIndexAsConst(IRContext * context,Instruction * access_chain)80 const analysis::Constant* GetAccessChainIndexAsConst(
81 IRContext* context, Instruction* access_chain) {
82 if (access_chain->NumInOperands() <= 1) {
83 return nullptr;
84 }
85 uint32_t idx_id = GetFirstIndexOfAccessChain(access_chain);
86 const analysis::Constant* idx_const =
87 context->get_constant_mgr()->FindDeclaredConstant(idx_id);
88 return idx_const;
89 }
90
GetFirstIndexOfAccessChain(Instruction * access_chain)91 uint32_t GetFirstIndexOfAccessChain(Instruction* access_chain) {
92 assert(access_chain->NumInOperands() > 1 &&
93 "OpAccessChain does not have Indexes operand");
94 return access_chain->GetSingleWordInOperand(kOpAccessChainInOperandIndexes);
95 }
96
GetNumberOfElementsForArrayOrStruct(IRContext * context,Instruction * var)97 uint32_t GetNumberOfElementsForArrayOrStruct(IRContext* context,
98 Instruction* var) {
99 uint32_t ptr_type_id = var->type_id();
100 Instruction* ptr_type_inst = context->get_def_use_mgr()->GetDef(ptr_type_id);
101 assert(ptr_type_inst->opcode() == spv::Op::OpTypePointer &&
102 "Variable should be a pointer to an array or structure.");
103 uint32_t pointee_type_id = ptr_type_inst->GetSingleWordInOperand(1);
104 Instruction* pointee_type_inst =
105 context->get_def_use_mgr()->GetDef(pointee_type_id);
106 if (pointee_type_inst->opcode() == spv::Op::OpTypeArray) {
107 return GetLengthOfArrayType(context, pointee_type_inst);
108 }
109 assert(pointee_type_inst->opcode() == spv::Op::OpTypeStruct &&
110 "Variable should be a pointer to an array or structure.");
111 return pointee_type_inst->NumInOperands();
112 }
113
114 } // namespace descsroautil
115 } // namespace opt
116 } // namespace spvtools
117