1 /*
2  * Copyright (C) 2014 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 "builder.h"
18 
19 #include "art_field-inl.h"
20 #include "base/arena_bit_vector.h"
21 #include "base/bit_vector-inl.h"
22 #include "base/logging.h"
23 #include "block_builder.h"
24 #include "data_type-inl.h"
25 #include "dex/verified_method.h"
26 #include "driver/compiler_options.h"
27 #include "driver/dex_compilation_unit.h"
28 #include "instruction_builder.h"
29 #include "mirror/class_loader.h"
30 #include "mirror/dex_cache.h"
31 #include "nodes.h"
32 #include "optimizing_compiler_stats.h"
33 #include "ssa_builder.h"
34 #include "thread.h"
35 #include "utils/dex_cache_arrays_layout-inl.h"
36 
37 namespace art {
38 
HGraphBuilder(HGraph * graph,const CodeItemDebugInfoAccessor & accessor,const DexCompilationUnit * dex_compilation_unit,const DexCompilationUnit * outer_compilation_unit,CompilerDriver * driver,CodeGenerator * code_generator,OptimizingCompilerStats * compiler_stats,ArrayRef<const uint8_t> interpreter_metadata,VariableSizedHandleScope * handles)39 HGraphBuilder::HGraphBuilder(HGraph* graph,
40                              const CodeItemDebugInfoAccessor& accessor,
41                              const DexCompilationUnit* dex_compilation_unit,
42                              const DexCompilationUnit* outer_compilation_unit,
43                              CompilerDriver* driver,
44                              CodeGenerator* code_generator,
45                              OptimizingCompilerStats* compiler_stats,
46                              ArrayRef<const uint8_t> interpreter_metadata,
47                              VariableSizedHandleScope* handles)
48     : graph_(graph),
49       dex_file_(&graph->GetDexFile()),
50       code_item_accessor_(accessor),
51       dex_compilation_unit_(dex_compilation_unit),
52       outer_compilation_unit_(outer_compilation_unit),
53       compiler_driver_(driver),
54       code_generator_(code_generator),
55       compilation_stats_(compiler_stats),
56       interpreter_metadata_(interpreter_metadata),
57       handles_(handles),
58       return_type_(DataType::FromShorty(dex_compilation_unit_->GetShorty()[0])) {}
59 
HGraphBuilder(HGraph * graph,const DexCompilationUnit * dex_compilation_unit,const CodeItemDebugInfoAccessor & accessor,VariableSizedHandleScope * handles,DataType::Type return_type)60 HGraphBuilder::HGraphBuilder(HGraph* graph,
61                              const DexCompilationUnit* dex_compilation_unit,
62                              const CodeItemDebugInfoAccessor& accessor,
63                              VariableSizedHandleScope* handles,
64                              DataType::Type return_type)
65     : graph_(graph),
66       dex_file_(&graph->GetDexFile()),
67       code_item_accessor_(accessor),
68       dex_compilation_unit_(dex_compilation_unit),
69       outer_compilation_unit_(nullptr),
70       compiler_driver_(nullptr),
71       code_generator_(nullptr),
72       compilation_stats_(nullptr),
73       handles_(handles),
74       return_type_(return_type) {}
75 
SkipCompilation(size_t number_of_branches)76 bool HGraphBuilder::SkipCompilation(size_t number_of_branches) {
77   if (compiler_driver_ == nullptr) {
78     // Note that the compiler driver is null when unit testing.
79     return false;
80   }
81 
82   const CompilerOptions& compiler_options = compiler_driver_->GetCompilerOptions();
83   CompilerFilter::Filter compiler_filter = compiler_options.GetCompilerFilter();
84   if (compiler_filter == CompilerFilter::kEverything) {
85     return false;
86   }
87 
88   const uint32_t code_units = code_item_accessor_.InsnsSizeInCodeUnits();
89   if (compiler_options.IsHugeMethod(code_units)) {
90     VLOG(compiler) << "Skip compilation of huge method "
91                    << dex_file_->PrettyMethod(dex_compilation_unit_->GetDexMethodIndex())
92                    << ": " << code_units << " code units";
93     MaybeRecordStat(compilation_stats_, MethodCompilationStat::kNotCompiledHugeMethod);
94     return true;
95   }
96 
97   // If it's large and contains no branches, it's likely to be machine generated initialization.
98   if (compiler_options.IsLargeMethod(code_units) && (number_of_branches == 0)) {
99     VLOG(compiler) << "Skip compilation of large method with no branch "
100                    << dex_file_->PrettyMethod(dex_compilation_unit_->GetDexMethodIndex())
101                    << ": " << code_units << " code units";
102     MaybeRecordStat(compilation_stats_, MethodCompilationStat::kNotCompiledLargeMethodNoBranches);
103     return true;
104   }
105 
106   return false;
107 }
108 
BuildGraph()109 GraphAnalysisResult HGraphBuilder::BuildGraph() {
110   DCHECK(code_item_accessor_.HasCodeItem());
111   DCHECK(graph_->GetBlocks().empty());
112 
113   graph_->SetNumberOfVRegs(code_item_accessor_.RegistersSize());
114   graph_->SetNumberOfInVRegs(code_item_accessor_.InsSize());
115   graph_->SetMaximumNumberOfOutVRegs(code_item_accessor_.OutsSize());
116   graph_->SetHasTryCatch(code_item_accessor_.TriesSize() != 0);
117 
118   // Use ScopedArenaAllocator for all local allocations.
119   ScopedArenaAllocator local_allocator(graph_->GetArenaStack());
120   HBasicBlockBuilder block_builder(graph_, dex_file_, code_item_accessor_, &local_allocator);
121   SsaBuilder ssa_builder(graph_,
122                          dex_compilation_unit_->GetClassLoader(),
123                          dex_compilation_unit_->GetDexCache(),
124                          handles_,
125                          &local_allocator);
126   HInstructionBuilder instruction_builder(graph_,
127                                           &block_builder,
128                                           &ssa_builder,
129                                           dex_file_,
130                                           code_item_accessor_,
131                                           return_type_,
132                                           dex_compilation_unit_,
133                                           outer_compilation_unit_,
134                                           compiler_driver_,
135                                           code_generator_,
136                                           interpreter_metadata_,
137                                           compilation_stats_,
138                                           handles_,
139                                           &local_allocator);
140 
141   // 1) Create basic blocks and link them together. Basic blocks are left
142   //    unpopulated with the exception of synthetic blocks, e.g. HTryBoundaries.
143   if (!block_builder.Build()) {
144     return kAnalysisInvalidBytecode;
145   }
146 
147   // 2) Decide whether to skip this method based on its code size and number
148   //    of branches.
149   if (SkipCompilation(block_builder.GetNumberOfBranches())) {
150     return kAnalysisSkipped;
151   }
152 
153   // 3) Build the dominator tree and fill in loop and try/catch metadata.
154   GraphAnalysisResult result = graph_->BuildDominatorTree();
155   if (result != kAnalysisSuccess) {
156     return result;
157   }
158 
159   // 4) Populate basic blocks with instructions.
160   if (!instruction_builder.Build()) {
161     return kAnalysisInvalidBytecode;
162   }
163 
164   // 5) Type the graph and eliminate dead/redundant phis.
165   return ssa_builder.BuildSsa();
166 }
167 
BuildIntrinsicGraph(ArtMethod * method)168 void HGraphBuilder::BuildIntrinsicGraph(ArtMethod* method) {
169   DCHECK(!code_item_accessor_.HasCodeItem());
170   DCHECK(graph_->GetBlocks().empty());
171 
172   // Determine the number of arguments and associated vregs.
173   uint32_t method_idx = dex_compilation_unit_->GetDexMethodIndex();
174   const char* shorty = dex_file_->GetMethodShorty(dex_file_->GetMethodId(method_idx));
175   size_t num_args = strlen(shorty + 1);
176   size_t num_wide_args = std::count(shorty + 1, shorty + 1 + num_args, 'J') +
177                          std::count(shorty + 1, shorty + 1 + num_args, 'D');
178   size_t num_arg_vregs = num_args + num_wide_args + (dex_compilation_unit_->IsStatic() ? 0u : 1u);
179 
180   // For simplicity, reserve 2 vregs (the maximum) for return value regardless of the return type.
181   size_t return_vregs = 2u;
182   graph_->SetNumberOfVRegs(return_vregs + num_arg_vregs);
183   graph_->SetNumberOfInVRegs(num_arg_vregs);
184   graph_->SetMaximumNumberOfOutVRegs(num_arg_vregs);
185   graph_->SetHasTryCatch(false);
186 
187   // Use ScopedArenaAllocator for all local allocations.
188   ScopedArenaAllocator local_allocator(graph_->GetArenaStack());
189   HBasicBlockBuilder block_builder(graph_,
190                                    dex_file_,
191                                    CodeItemDebugInfoAccessor(),
192                                    &local_allocator);
193   SsaBuilder ssa_builder(graph_,
194                          dex_compilation_unit_->GetClassLoader(),
195                          dex_compilation_unit_->GetDexCache(),
196                          handles_,
197                          &local_allocator);
198   HInstructionBuilder instruction_builder(graph_,
199                                           &block_builder,
200                                           &ssa_builder,
201                                           dex_file_,
202                                           CodeItemDebugInfoAccessor(),
203                                           return_type_,
204                                           dex_compilation_unit_,
205                                           outer_compilation_unit_,
206                                           compiler_driver_,
207                                           code_generator_,
208                                           interpreter_metadata_,
209                                           compilation_stats_,
210                                           handles_,
211                                           &local_allocator);
212 
213   // 1) Create basic blocks for the intrinsic and link them together.
214   block_builder.BuildIntrinsic();
215 
216   // 2) Build the trivial dominator tree.
217   GraphAnalysisResult bdt_result = graph_->BuildDominatorTree();
218   DCHECK_EQ(bdt_result, kAnalysisSuccess);
219 
220   // 3) Populate basic blocks with instructions for the intrinsic.
221   instruction_builder.BuildIntrinsic(method);
222 
223   // 4) Type the graph (no dead/redundant phis to eliminate).
224   GraphAnalysisResult build_ssa_result = ssa_builder.BuildSsa();
225   DCHECK_EQ(build_ssa_result, kAnalysisSuccess);
226 }
227 
228 }  // namespace art
229