1// Copyright (c) 2017 The Khronos Group Inc.
2// Copyright (c) 2017 Valve Corporation
3// Copyright (c) 2017 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#ifndef SOURCE_OPT_LOCAL_ACCESS_CHAIN_CONVERT_PASS_H_
18#define SOURCE_OPT_LOCAL_ACCESS_CHAIN_CONVERT_PASS_H_
19
20#include <algorithm>
21#include <map>
22#include <memory>
23#include <queue>
24#include <string>
25#include <unordered_map>
26#include <unordered_set>
27#include <utility>
28#include <vector>
29
30#include "source/opt/basic_block.h"
31#include "source/opt/def_use_manager.h"
32#include "source/opt/mem_pass.h"
33#include "source/opt/module.h"
34
35namespace spvtools {
36namespace opt {
37
38// See optimizer.hpp for documentation.
39class LocalAccessChainConvertPass : public MemPass {
40 public:
41 LocalAccessChainConvertPass();
42
43 const char* name() const override { return "convert-local-access-chains"; }
44 Status Process() override;
45
46 IRContext::Analysis GetPreservedAnalyses() override {
47 return IRContext::kAnalysisDefUse | IRContext::kAnalysisConstants |
48 IRContext::kAnalysisTypes;
49 }
50
51 using ProcessFunction = std::function<bool(Function*)>;
52
53 private:
54 // Return true if all refs through |ptrId| are only loads or stores and
55 // cache ptrId in supported_ref_ptrs_. TODO(dnovillo): This function is
56 // replicated in other passes and it's slightly different in every pass. Is it
57 // possible to make one common implementation?
58 bool HasOnlySupportedRefs(uint32_t ptrId);
59
60 // Search |func| and cache function scope variables of target type that are
61 // not accessed with non-constant-index access chains. Also cache non-target
62 // variables.
63 void FindTargetVars(Function* func);
64
65 // Build instruction from |opcode|, |typeId|, |resultId|, and |in_opnds|.
66 // Append to |newInsts|.
67 void BuildAndAppendInst(SpvOp opcode, uint32_t typeId, uint32_t resultId,
68 const std::vector<Operand>& in_opnds,
69 std::vector<std::unique_ptr<Instruction>>* newInsts);
70
71 // Build load of variable in |ptrInst| and append to |newInsts|.
72 // Return var in |varId| and its pointee type in |varPteTypeId|.
73 uint32_t BuildAndAppendVarLoad(
74 const Instruction* ptrInst, uint32_t* varId, uint32_t* varPteTypeId,
75 std::vector<std::unique_ptr<Instruction>>* newInsts);
76
77 // Append literal integer operands to |in_opnds| corresponding to constant
78 // integer operands from access chain |ptrInst|. Assumes all indices in
79 // access chains are OpConstant.
80 void AppendConstantOperands(const Instruction* ptrInst,
81 std::vector<Operand>* in_opnds);
82
83 // Create a load/insert/store equivalent to a store of
84 // |valId| through (constant index) access chaing |ptrInst|.
85 // Append to |newInsts|. Returns true if successful.
86 bool GenAccessChainStoreReplacement(
87 const Instruction* ptrInst, uint32_t valId,
88 std::vector<std::unique_ptr<Instruction>>* newInsts);
89
90 // For the (constant index) access chain |address_inst|, create an
91 // equivalent load and extract that replaces |original_load|. The result id
92 // of the extract will be the same as the original result id of
93 // |original_load|. Returns true if successful.
94 bool ReplaceAccessChainLoad(const Instruction* address_inst,
95 Instruction* original_load);
96
97 // Return true if all indices of access chain |acp| are OpConstant integers
98 bool IsConstantIndexAccessChain(const Instruction* acp) const;
99
100 // Identify all function scope variables of target type which are
101 // accessed only with loads, stores and access chains with constant
102 // indices. Convert all loads and stores of such variables into equivalent
103 // loads, stores, extracts and inserts. This unifies access to these
104 // variables to a single mode and simplifies analysis and optimization.
105 // See IsTargetType() for targeted types.
106 //
107 // Nested access chains and pointer access chains are not currently
108 // converted.
109 //
110 // Returns a status to indicate success or failure, and change or no change.
111 Status ConvertLocalAccessChains(Function* func);
112
113 // Initialize extensions whitelist
114 void InitExtensions();
115
116 // Return true if all extensions in this module are allowed by this pass.
117 bool AllExtensionsSupported() const;
118
119 void Initialize();
120 Pass::Status ProcessImpl();
121
122 // Variables with only supported references, ie. loads and stores using
123 // variable directly or through non-ptr access chains.
124 std::unordered_set<uint32_t> supported_ref_ptrs_;
125
126 // Extensions supported by this pass.
127 std::unordered_set<std::string> extensions_whitelist_;
128};
129
130} // namespace opt
131} // namespace spvtools
132
133#endif // SOURCE_OPT_LOCAL_ACCESS_CHAIN_CONVERT_PASS_H_
134