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 "ir_builder.h"
23 #include "source/opt/ir_context.h"
24 #include "type_manager.h"
25
26 namespace spvtools {
27 namespace opt {
28
29 namespace {
30
31 // Input Operand Indices
32 static const int kSpvVariableStorageClassInIdx = 0;
33
34 // Avoid unused variable warning/error on Linux
35 #ifndef NDEBUG
36 #define USE_ASSERT(x) assert(x)
37 #else
38 #define USE_ASSERT(x) ((void)(x))
39 #endif
40
41 // Folding rule function which attempts to replace |op(OpLoad(a),...)|
42 // by |op(a,...)|, where |op| is one of the GLSLstd450 InterpolateAt*
43 // instructions. Returns true if replaced, false otherwise.
ReplaceInternalInterpolate(IRContext * ctx,Instruction * inst,const std::vector<const analysis::Constant * > &)44 bool ReplaceInternalInterpolate(IRContext* ctx, Instruction* inst,
45 const std::vector<const analysis::Constant*>&) {
46 uint32_t glsl450_ext_inst_id =
47 ctx->get_feature_mgr()->GetExtInstImportId_GLSLstd450();
48 assert(glsl450_ext_inst_id != 0);
49
50 uint32_t ext_opcode = inst->GetSingleWordInOperand(1);
51
52 uint32_t op1_id = inst->GetSingleWordInOperand(2);
53
54 Instruction* load_inst = ctx->get_def_use_mgr()->GetDef(op1_id);
55 if (load_inst->opcode() != SpvOpLoad) return false;
56
57 Instruction* base_inst = load_inst->GetBaseAddress();
58 USE_ASSERT(base_inst->opcode() == SpvOpVariable &&
59 base_inst->GetSingleWordInOperand(kSpvVariableStorageClassInIdx) ==
60 SpvStorageClassInput &&
61 "unexpected interpolant in InterpolateAt*");
62
63 uint32_t ptr_id = load_inst->GetSingleWordInOperand(0);
64 uint32_t op2_id = (ext_opcode != GLSLstd450InterpolateAtCentroid)
65 ? inst->GetSingleWordInOperand(3)
66 : 0;
67
68 Instruction::OperandList new_operands;
69 new_operands.push_back({SPV_OPERAND_TYPE_ID, {glsl450_ext_inst_id}});
70 new_operands.push_back(
71 {SPV_OPERAND_TYPE_EXTENSION_INSTRUCTION_NUMBER, {ext_opcode}});
72 new_operands.push_back({SPV_OPERAND_TYPE_ID, {ptr_id}});
73 if (op2_id != 0) new_operands.push_back({SPV_OPERAND_TYPE_ID, {op2_id}});
74
75 inst->SetInOperands(std::move(new_operands));
76 ctx->UpdateDefUse(inst);
77 return true;
78 }
79
80 class InterpFoldingRules : public FoldingRules {
81 public:
InterpFoldingRules(IRContext * ctx)82 explicit InterpFoldingRules(IRContext* ctx) : FoldingRules(ctx) {}
83
84 protected:
AddFoldingRules()85 virtual void AddFoldingRules() override {
86 uint32_t extension_id =
87 context()->get_feature_mgr()->GetExtInstImportId_GLSLstd450();
88
89 if (extension_id != 0) {
90 ext_rules_[{extension_id, GLSLstd450InterpolateAtCentroid}].push_back(
91 ReplaceInternalInterpolate);
92 ext_rules_[{extension_id, GLSLstd450InterpolateAtSample}].push_back(
93 ReplaceInternalInterpolate);
94 ext_rules_[{extension_id, GLSLstd450InterpolateAtOffset}].push_back(
95 ReplaceInternalInterpolate);
96 }
97 }
98 };
99
100 class InterpConstFoldingRules : public ConstantFoldingRules {
101 public:
InterpConstFoldingRules(IRContext * ctx)102 InterpConstFoldingRules(IRContext* ctx) : ConstantFoldingRules(ctx) {}
103
104 protected:
AddFoldingRules()105 virtual void AddFoldingRules() override {}
106 };
107
108 } // namespace
109
Process()110 Pass::Status InterpFixupPass::Process() {
111 bool changed = false;
112
113 // Traverse the body of the functions to replace instructions that require
114 // the extensions.
115 InstructionFolder folder(
116 context(),
117 std::unique_ptr<InterpFoldingRules>(new InterpFoldingRules(context())),
118 MakeUnique<InterpConstFoldingRules>(context()));
119 for (Function& func : *get_module()) {
120 func.ForEachInst([&changed, &folder](Instruction* inst) {
121 if (folder.FoldInstruction(inst)) {
122 changed = true;
123 }
124 });
125 }
126
127 return changed ? Status::SuccessWithChange : Status::SuccessWithoutChange;
128 }
129
130 } // namespace opt
131 } // namespace spvtools
132