1 // Copyright (c) 2021 The Khronos Group Inc.
2 // Copyright (c) 2021 Valve Corporation
3 // Copyright (c) 2021 LunarG Inc.
4 //
5 // Licensed under the Apache License, Version 2.0 (the "License");
6 // you may not use this file except in compliance with the License.
7 // You may obtain a copy of the License at
8 //
9 // http://www.apache.org/licenses/LICENSE-2.0
10 //
11 // Unless required by applicable law or agreed to in writing, software
12 // distributed under the License is distributed on an "AS IS" BASIS,
13 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 // See the License for the specific language governing permissions and
15 // limitations under the License.
16
17 #include "source/opt/interp_fixup_pass.h"
18
19 #include <set>
20 #include <string>
21
22 #include "source/opt/ir_context.h"
23 #include "type_manager.h"
24
25 namespace spvtools {
26 namespace opt {
27 namespace {
28
29 // Input Operand Indices
30 constexpr int kSpvVariableStorageClassInIdx = 0;
31
32 // Folding rule function which attempts to replace |op(OpLoad(a),...)|
33 // by |op(a,...)|, where |op| is one of the GLSLstd450 InterpolateAt*
34 // instructions. Returns true if replaced, false otherwise.
ReplaceInternalInterpolate(IRContext * ctx,Instruction * inst,const std::vector<const analysis::Constant * > &)35 bool ReplaceInternalInterpolate(IRContext* ctx, Instruction* inst,
36 const std::vector<const analysis::Constant*>&) {
37 uint32_t glsl450_ext_inst_id =
38 ctx->get_feature_mgr()->GetExtInstImportId_GLSLstd450();
39 assert(glsl450_ext_inst_id != 0);
40
41 uint32_t ext_opcode = inst->GetSingleWordInOperand(1);
42
43 uint32_t op1_id = inst->GetSingleWordInOperand(2);
44
45 Instruction* load_inst = ctx->get_def_use_mgr()->GetDef(op1_id);
46 if (load_inst->opcode() != spv::Op::OpLoad) return false;
47
48 Instruction* base_inst = load_inst->GetBaseAddress();
49 USE_ASSERT(base_inst->opcode() == spv::Op::OpVariable &&
50 spv::StorageClass(base_inst->GetSingleWordInOperand(
51 kSpvVariableStorageClassInIdx)) == spv::StorageClass::Input &&
52 "unexpected interpolant in InterpolateAt*");
53
54 uint32_t ptr_id = load_inst->GetSingleWordInOperand(0);
55 uint32_t op2_id = (ext_opcode != GLSLstd450InterpolateAtCentroid)
56 ? inst->GetSingleWordInOperand(3)
57 : 0;
58
59 Instruction::OperandList new_operands;
60 new_operands.push_back({SPV_OPERAND_TYPE_ID, {glsl450_ext_inst_id}});
61 new_operands.push_back(
62 {SPV_OPERAND_TYPE_EXTENSION_INSTRUCTION_NUMBER, {ext_opcode}});
63 new_operands.push_back({SPV_OPERAND_TYPE_ID, {ptr_id}});
64 if (op2_id != 0) new_operands.push_back({SPV_OPERAND_TYPE_ID, {op2_id}});
65
66 inst->SetInOperands(std::move(new_operands));
67 ctx->UpdateDefUse(inst);
68 return true;
69 }
70
71 class InterpFoldingRules : public FoldingRules {
72 public:
InterpFoldingRules(IRContext * ctx)73 explicit InterpFoldingRules(IRContext* ctx) : FoldingRules(ctx) {}
74
75 protected:
AddFoldingRules()76 virtual void AddFoldingRules() override {
77 uint32_t extension_id =
78 context()->get_feature_mgr()->GetExtInstImportId_GLSLstd450();
79
80 if (extension_id != 0) {
81 ext_rules_[{extension_id, GLSLstd450InterpolateAtCentroid}].push_back(
82 ReplaceInternalInterpolate);
83 ext_rules_[{extension_id, GLSLstd450InterpolateAtSample}].push_back(
84 ReplaceInternalInterpolate);
85 ext_rules_[{extension_id, GLSLstd450InterpolateAtOffset}].push_back(
86 ReplaceInternalInterpolate);
87 }
88 }
89 };
90
91 class InterpConstFoldingRules : public ConstantFoldingRules {
92 public:
InterpConstFoldingRules(IRContext * ctx)93 InterpConstFoldingRules(IRContext* ctx) : ConstantFoldingRules(ctx) {}
94
95 protected:
AddFoldingRules()96 virtual void AddFoldingRules() override {}
97 };
98
99 } // namespace
100
Process()101 Pass::Status InterpFixupPass::Process() {
102 bool changed = false;
103
104 // Traverse the body of the functions to replace instructions that require
105 // the extensions.
106 InstructionFolder folder(
107 context(),
108 std::unique_ptr<InterpFoldingRules>(new InterpFoldingRules(context())),
109 MakeUnique<InterpConstFoldingRules>(context()));
110 for (Function& func : *get_module()) {
111 func.ForEachInst([&changed, &folder](Instruction* inst) {
112 if (folder.FoldInstruction(inst)) {
113 changed = true;
114 }
115 });
116 }
117
118 return changed ? Status::SuccessWithChange : Status::SuccessWithoutChange;
119 }
120
121 } // namespace opt
122 } // namespace spvtools
123