1 /*
2 * Copyright (C) 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "dex_cache_array_fixups_arm.h"
18
19 #include "base/arena_containers.h"
20 #ifdef ART_USE_OLD_ARM_BACKEND
21 #include "code_generator_arm.h"
22 #include "intrinsics_arm.h"
23 #else
24 #include "code_generator_arm_vixl.h"
25 #include "intrinsics_arm_vixl.h"
26 #endif
27 #include "utils/dex_cache_arrays_layout-inl.h"
28
29 namespace art {
30 namespace arm {
31 #ifdef ART_USE_OLD_ARM_BACKEND
32 typedef CodeGeneratorARM CodeGeneratorARMType;
33 typedef IntrinsicLocationsBuilderARM IntrinsicLocationsBuilderARMType;
34 #else
35 typedef CodeGeneratorARMVIXL CodeGeneratorARMType;
36 typedef IntrinsicLocationsBuilderARMVIXL IntrinsicLocationsBuilderARMType;
37 #endif
38
39 /**
40 * Finds instructions that need the dex cache arrays base as an input.
41 */
42 class DexCacheArrayFixupsVisitor : public HGraphVisitor {
43 public:
DexCacheArrayFixupsVisitor(HGraph * graph,CodeGenerator * codegen)44 DexCacheArrayFixupsVisitor(HGraph* graph, CodeGenerator* codegen)
45 : HGraphVisitor(graph),
46 codegen_(down_cast<CodeGeneratorARMType*>(codegen)),
47 dex_cache_array_bases_(std::less<const DexFile*>(),
48 // Attribute memory use to code generator.
49 graph->GetArena()->Adapter(kArenaAllocCodeGenerator)) {}
50
MoveBasesIfNeeded()51 void MoveBasesIfNeeded() {
52 for (const auto& entry : dex_cache_array_bases_) {
53 // Bring the base closer to the first use (previously, it was in the
54 // entry block) and relieve some pressure on the register allocator
55 // while avoiding recalculation of the base in a loop.
56 HArmDexCacheArraysBase* base = entry.second;
57 base->MoveBeforeFirstUserAndOutOfLoops();
58 }
59 }
60
61 private:
VisitInvokeStaticOrDirect(HInvokeStaticOrDirect * invoke)62 void VisitInvokeStaticOrDirect(HInvokeStaticOrDirect* invoke) OVERRIDE {
63 // If this is an invoke with PC-relative access to the dex cache methods array,
64 // we need to add the dex cache arrays base as the special input.
65 if (invoke->HasPcRelativeDexCache() &&
66 !IsCallFreeIntrinsic<IntrinsicLocationsBuilderARMType>(invoke, codegen_)) {
67 HArmDexCacheArraysBase* base =
68 GetOrCreateDexCacheArrayBase(invoke, invoke->GetDexFileForPcRelativeDexCache());
69 // Update the element offset in base.
70 DexCacheArraysLayout layout(kArmPointerSize, &invoke->GetDexFileForPcRelativeDexCache());
71 base->UpdateElementOffset(layout.MethodOffset(invoke->GetDexMethodIndex()));
72 // Add the special argument base to the method.
73 DCHECK(!invoke->HasCurrentMethodInput());
74 invoke->AddSpecialInput(base);
75 }
76 }
77
GetOrCreateDexCacheArrayBase(HInstruction * cursor,const DexFile & dex_file)78 HArmDexCacheArraysBase* GetOrCreateDexCacheArrayBase(HInstruction* cursor,
79 const DexFile& dex_file) {
80 if (GetGraph()->HasIrreducibleLoops()) {
81 HArmDexCacheArraysBase* base = new (GetGraph()->GetArena()) HArmDexCacheArraysBase(dex_file);
82 cursor->GetBlock()->InsertInstructionBefore(base, cursor);
83 return base;
84 } else {
85 // Ensure we only initialize the pointer once for each dex file.
86 auto lb = dex_cache_array_bases_.lower_bound(&dex_file);
87 if (lb != dex_cache_array_bases_.end() &&
88 !dex_cache_array_bases_.key_comp()(&dex_file, lb->first)) {
89 return lb->second;
90 }
91
92 // Insert the base at the start of the entry block, move it to a better
93 // position later in MoveBaseIfNeeded().
94 HArmDexCacheArraysBase* base = new (GetGraph()->GetArena()) HArmDexCacheArraysBase(dex_file);
95 HBasicBlock* entry_block = GetGraph()->GetEntryBlock();
96 entry_block->InsertInstructionBefore(base, entry_block->GetFirstInstruction());
97 dex_cache_array_bases_.PutBefore(lb, &dex_file, base);
98 return base;
99 }
100 }
101
102 CodeGeneratorARMType* codegen_;
103
104 using DexCacheArraysBaseMap =
105 ArenaSafeMap<const DexFile*, HArmDexCacheArraysBase*, std::less<const DexFile*>>;
106 DexCacheArraysBaseMap dex_cache_array_bases_;
107 };
108
Run()109 void DexCacheArrayFixups::Run() {
110 DexCacheArrayFixupsVisitor visitor(graph_, codegen_);
111 visitor.VisitInsertionOrder();
112 visitor.MoveBasesIfNeeded();
113 }
114
115 } // namespace arm
116 } // namespace art
117