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
21 const uint32_t kOpAccessChainInOperandIndexes = 1;
22
23 // Returns the length of array type |type|.
GetLengthOfArrayType(IRContext * context,Instruction * type)24 uint32_t GetLengthOfArrayType(IRContext* context, Instruction* type) {
25 assert(type->opcode() == SpvOpTypeArray && "type must be array");
26 uint32_t length_id = type->GetSingleWordInOperand(1);
27 const analysis::Constant* length_const =
28 context->get_constant_mgr()->FindDeclaredConstant(length_id);
29 assert(length_const != nullptr);
30 return length_const->GetU32();
31 }
32
33 } // namespace
34
35 namespace descsroautil {
36
IsDescriptorArray(IRContext * context,Instruction * var)37 bool IsDescriptorArray(IRContext* context, Instruction* var) {
38 if (var->opcode() != SpvOpVariable) {
39 return false;
40 }
41
42 uint32_t ptr_type_id = var->type_id();
43 Instruction* ptr_type_inst = context->get_def_use_mgr()->GetDef(ptr_type_id);
44 if (ptr_type_inst->opcode() != SpvOpTypePointer) {
45 return false;
46 }
47
48 uint32_t var_type_id = ptr_type_inst->GetSingleWordInOperand(1);
49 Instruction* var_type_inst = context->get_def_use_mgr()->GetDef(var_type_id);
50 if (var_type_inst->opcode() != SpvOpTypeArray &&
51 var_type_inst->opcode() != SpvOpTypeStruct) {
52 return false;
53 }
54
55 // All structures with descriptor assignments must be replaced by variables,
56 // one for each of their members - with the exceptions of buffers.
57 if (IsTypeOfStructuredBuffer(context, var_type_inst)) {
58 return false;
59 }
60
61 if (!context->get_decoration_mgr()->HasDecoration(
62 var->result_id(), SpvDecorationDescriptorSet)) {
63 return false;
64 }
65
66 return context->get_decoration_mgr()->HasDecoration(var->result_id(),
67 SpvDecorationBinding);
68 }
69
IsTypeOfStructuredBuffer(IRContext * context,const Instruction * type)70 bool IsTypeOfStructuredBuffer(IRContext* context, const Instruction* type) {
71 if (type->opcode() != SpvOpTypeStruct) {
72 return false;
73 }
74
75 // All buffers have offset decorations for members of their structure types.
76 // This is how we distinguish it from a structure of descriptors.
77 return context->get_decoration_mgr()->HasDecoration(type->result_id(),
78 SpvDecorationOffset);
79 }
80
GetAccessChainIndexAsConst(IRContext * context,Instruction * access_chain)81 const analysis::Constant* GetAccessChainIndexAsConst(
82 IRContext* context, Instruction* access_chain) {
83 if (access_chain->NumInOperands() <= 1) {
84 return nullptr;
85 }
86 uint32_t idx_id = GetFirstIndexOfAccessChain(access_chain);
87 const analysis::Constant* idx_const =
88 context->get_constant_mgr()->FindDeclaredConstant(idx_id);
89 return idx_const;
90 }
91
GetFirstIndexOfAccessChain(Instruction * access_chain)92 uint32_t GetFirstIndexOfAccessChain(Instruction* access_chain) {
93 assert(access_chain->NumInOperands() > 1 &&
94 "OpAccessChain does not have Indexes operand");
95 return access_chain->GetSingleWordInOperand(kOpAccessChainInOperandIndexes);
96 }
97
GetNumberOfElementsForArrayOrStruct(IRContext * context,Instruction * var)98 uint32_t GetNumberOfElementsForArrayOrStruct(IRContext* context,
99 Instruction* var) {
100 uint32_t ptr_type_id = var->type_id();
101 Instruction* ptr_type_inst = context->get_def_use_mgr()->GetDef(ptr_type_id);
102 assert(ptr_type_inst->opcode() == SpvOpTypePointer &&
103 "Variable should be a pointer to an array or structure.");
104 uint32_t pointee_type_id = ptr_type_inst->GetSingleWordInOperand(1);
105 Instruction* pointee_type_inst =
106 context->get_def_use_mgr()->GetDef(pointee_type_id);
107 if (pointee_type_inst->opcode() == SpvOpTypeArray) {
108 return GetLengthOfArrayType(context, pointee_type_inst);
109 }
110 assert(pointee_type_inst->opcode() == SpvOpTypeStruct &&
111 "Variable should be a pointer to an array or structure.");
112 return pointee_type_inst->NumInOperands();
113 }
114
115 } // namespace descsroautil
116 } // namespace opt
117 } // namespace spvtools
118