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 "inliner.h"
18 
19 #include "art_method-inl.h"
20 #include "base/enums.h"
21 #include "base/logging.h"
22 #include "builder.h"
23 #include "class_linker.h"
24 #include "class_root-inl.h"
25 #include "constant_folding.h"
26 #include "data_type-inl.h"
27 #include "dead_code_elimination.h"
28 #include "dex/inline_method_analyser.h"
29 #include "dex/verification_results.h"
30 #include "dex/verified_method.h"
31 #include "driver/compiler_options.h"
32 #include "driver/dex_compilation_unit.h"
33 #include "instruction_simplifier.h"
34 #include "intrinsics.h"
35 #include "jit/jit.h"
36 #include "jit/jit_code_cache.h"
37 #include "mirror/class_loader.h"
38 #include "mirror/dex_cache.h"
39 #include "mirror/object_array-alloc-inl.h"
40 #include "mirror/object_array-inl.h"
41 #include "nodes.h"
42 #include "reference_type_propagation.h"
43 #include "register_allocator_linear_scan.h"
44 #include "scoped_thread_state_change-inl.h"
45 #include "sharpening.h"
46 #include "ssa_builder.h"
47 #include "ssa_phi_elimination.h"
48 #include "thread.h"
49 
50 namespace art {
51 
52 // Instruction limit to control memory.
53 static constexpr size_t kMaximumNumberOfTotalInstructions = 1024;
54 
55 // Maximum number of instructions for considering a method small,
56 // which we will always try to inline if the other non-instruction limits
57 // are not reached.
58 static constexpr size_t kMaximumNumberOfInstructionsForSmallMethod = 3;
59 
60 // Limit the number of dex registers that we accumulate while inlining
61 // to avoid creating large amount of nested environments.
62 static constexpr size_t kMaximumNumberOfCumulatedDexRegisters = 32;
63 
64 // Limit recursive call inlining, which do not benefit from too
65 // much inlining compared to code locality.
66 static constexpr size_t kMaximumNumberOfRecursiveCalls = 4;
67 
68 // Controls the use of inline caches in AOT mode.
69 static constexpr bool kUseAOTInlineCaches = true;
70 
71 // We check for line numbers to make sure the DepthString implementation
72 // aligns the output nicely.
73 #define LOG_INTERNAL(msg) \
74   static_assert(__LINE__ > 10, "Unhandled line number"); \
75   static_assert(__LINE__ < 10000, "Unhandled line number"); \
76   VLOG(compiler) << DepthString(__LINE__) << msg
77 
78 #define LOG_TRY() LOG_INTERNAL("Try inlinining call: ")
79 #define LOG_NOTE() LOG_INTERNAL("Note: ")
80 #define LOG_SUCCESS() LOG_INTERNAL("Success: ")
81 #define LOG_FAIL(stats_ptr, stat) MaybeRecordStat(stats_ptr, stat); LOG_INTERNAL("Fail: ")
82 #define LOG_FAIL_NO_STAT() LOG_INTERNAL("Fail: ")
83 
DepthString(int line) const84 std::string HInliner::DepthString(int line) const {
85   std::string value;
86   // Indent according to the inlining depth.
87   size_t count = depth_;
88   // Line numbers get printed in the log, so add a space if the log's line is less
89   // than 1000, and two if less than 100. 10 cannot be reached as it's the copyright.
90   if (!kIsTargetBuild) {
91     if (line < 100) {
92       value += " ";
93     }
94     if (line < 1000) {
95       value += " ";
96     }
97     // Safeguard if this file reaches more than 10000 lines.
98     DCHECK_LT(line, 10000);
99   }
100   for (size_t i = 0; i < count; ++i) {
101     value += "  ";
102   }
103   return value;
104 }
105 
CountNumberOfInstructions(HGraph * graph)106 static size_t CountNumberOfInstructions(HGraph* graph) {
107   size_t number_of_instructions = 0;
108   for (HBasicBlock* block : graph->GetReversePostOrderSkipEntryBlock()) {
109     for (HInstructionIterator instr_it(block->GetInstructions());
110          !instr_it.Done();
111          instr_it.Advance()) {
112       ++number_of_instructions;
113     }
114   }
115   return number_of_instructions;
116 }
117 
UpdateInliningBudget()118 void HInliner::UpdateInliningBudget() {
119   if (total_number_of_instructions_ >= kMaximumNumberOfTotalInstructions) {
120     // Always try to inline small methods.
121     inlining_budget_ = kMaximumNumberOfInstructionsForSmallMethod;
122   } else {
123     inlining_budget_ = std::max(
124         kMaximumNumberOfInstructionsForSmallMethod,
125         kMaximumNumberOfTotalInstructions - total_number_of_instructions_);
126   }
127 }
128 
Run()129 bool HInliner::Run() {
130   if (codegen_->GetCompilerOptions().GetInlineMaxCodeUnits() == 0) {
131     // Inlining effectively disabled.
132     return false;
133   } else if (graph_->IsDebuggable()) {
134     // For simplicity, we currently never inline when the graph is debuggable. This avoids
135     // doing some logic in the runtime to discover if a method could have been inlined.
136     return false;
137   }
138 
139   bool didInline = false;
140 
141   // Initialize the number of instructions for the method being compiled. Recursive calls
142   // to HInliner::Run have already updated the instruction count.
143   if (outermost_graph_ == graph_) {
144     total_number_of_instructions_ = CountNumberOfInstructions(graph_);
145   }
146 
147   UpdateInliningBudget();
148   DCHECK_NE(total_number_of_instructions_, 0u);
149   DCHECK_NE(inlining_budget_, 0u);
150 
151   // If we're compiling tests, honor inlining directives in method names:
152   // - if a method's name contains the substring "$noinline$", do not
153   //   inline that method;
154   // - if a method's name contains the substring "$inline$", ensure
155   //   that this method is actually inlined.
156   // We limit the latter to AOT compilation, as the JIT may or may not inline
157   // depending on the state of classes at runtime.
158   const bool honor_noinline_directives = codegen_->GetCompilerOptions().CompileArtTest();
159   const bool honor_inline_directives =
160       honor_noinline_directives && Runtime::Current()->IsAotCompiler();
161 
162   // Keep a copy of all blocks when starting the visit.
163   ArenaVector<HBasicBlock*> blocks = graph_->GetReversePostOrder();
164   DCHECK(!blocks.empty());
165   // Because we are changing the graph when inlining,
166   // we just iterate over the blocks of the outer method.
167   // This avoids doing the inlining work again on the inlined blocks.
168   for (HBasicBlock* block : blocks) {
169     for (HInstruction* instruction = block->GetFirstInstruction(); instruction != nullptr;) {
170       HInstruction* next = instruction->GetNext();
171       HInvoke* call = instruction->AsInvoke();
172       // As long as the call is not intrinsified, it is worth trying to inline.
173       if (call != nullptr && call->GetIntrinsic() == Intrinsics::kNone) {
174         if (honor_noinline_directives) {
175           // Debugging case: directives in method names control or assert on inlining.
176           std::string callee_name = outer_compilation_unit_.GetDexFile()->PrettyMethod(
177               call->GetDexMethodIndex(), /* with_signature= */ false);
178           // Tests prevent inlining by having $noinline$ in their method names.
179           if (callee_name.find("$noinline$") == std::string::npos) {
180             if (TryInline(call)) {
181               didInline = true;
182             } else if (honor_inline_directives) {
183               bool should_have_inlined = (callee_name.find("$inline$") != std::string::npos);
184               CHECK(!should_have_inlined) << "Could not inline " << callee_name;
185             }
186           }
187         } else {
188           DCHECK(!honor_inline_directives);
189           // Normal case: try to inline.
190           if (TryInline(call)) {
191             didInline = true;
192           }
193         }
194       }
195       instruction = next;
196     }
197   }
198 
199   return didInline;
200 }
201 
IsMethodOrDeclaringClassFinal(ArtMethod * method)202 static bool IsMethodOrDeclaringClassFinal(ArtMethod* method)
203     REQUIRES_SHARED(Locks::mutator_lock_) {
204   return method->IsFinal() || method->GetDeclaringClass()->IsFinal();
205 }
206 
207 /**
208  * Given the `resolved_method` looked up in the dex cache, try to find
209  * the actual runtime target of an interface or virtual call.
210  * Return nullptr if the runtime target cannot be proven.
211  */
FindVirtualOrInterfaceTarget(HInvoke * invoke,ArtMethod * resolved_method)212 static ArtMethod* FindVirtualOrInterfaceTarget(HInvoke* invoke, ArtMethod* resolved_method)
213     REQUIRES_SHARED(Locks::mutator_lock_) {
214   if (IsMethodOrDeclaringClassFinal(resolved_method)) {
215     // No need to lookup further, the resolved method will be the target.
216     return resolved_method;
217   }
218 
219   HInstruction* receiver = invoke->InputAt(0);
220   if (receiver->IsNullCheck()) {
221     // Due to multiple levels of inlining within the same pass, it might be that
222     // null check does not have the reference type of the actual receiver.
223     receiver = receiver->InputAt(0);
224   }
225   ReferenceTypeInfo info = receiver->GetReferenceTypeInfo();
226   DCHECK(info.IsValid()) << "Invalid RTI for " << receiver->DebugName();
227   if (!info.IsExact()) {
228     // We currently only support inlining with known receivers.
229     // TODO: Remove this check, we should be able to inline final methods
230     // on unknown receivers.
231     return nullptr;
232   } else if (info.GetTypeHandle()->IsInterface()) {
233     // Statically knowing that the receiver has an interface type cannot
234     // help us find what is the target method.
235     return nullptr;
236   } else if (!resolved_method->GetDeclaringClass()->IsAssignableFrom(info.GetTypeHandle().Get())) {
237     // The method that we're trying to call is not in the receiver's class or super classes.
238     return nullptr;
239   } else if (info.GetTypeHandle()->IsErroneous()) {
240     // If the type is erroneous, do not go further, as we are going to query the vtable or
241     // imt table, that we can only safely do on non-erroneous classes.
242     return nullptr;
243   }
244 
245   ClassLinker* cl = Runtime::Current()->GetClassLinker();
246   PointerSize pointer_size = cl->GetImagePointerSize();
247   if (invoke->IsInvokeInterface()) {
248     resolved_method = info.GetTypeHandle()->FindVirtualMethodForInterface(
249         resolved_method, pointer_size);
250   } else {
251     DCHECK(invoke->IsInvokeVirtual());
252     resolved_method = info.GetTypeHandle()->FindVirtualMethodForVirtual(
253         resolved_method, pointer_size);
254   }
255 
256   if (resolved_method == nullptr) {
257     // The information we had on the receiver was not enough to find
258     // the target method. Since we check above the exact type of the receiver,
259     // the only reason this can happen is an IncompatibleClassChangeError.
260     return nullptr;
261   } else if (!resolved_method->IsInvokable()) {
262     // The information we had on the receiver was not enough to find
263     // the target method. Since we check above the exact type of the receiver,
264     // the only reason this can happen is an IncompatibleClassChangeError.
265     return nullptr;
266   } else if (IsMethodOrDeclaringClassFinal(resolved_method)) {
267     // A final method has to be the target method.
268     return resolved_method;
269   } else if (info.IsExact()) {
270     // If we found a method and the receiver's concrete type is statically
271     // known, we know for sure the target.
272     return resolved_method;
273   } else {
274     // Even if we did find a method, the receiver type was not enough to
275     // statically find the runtime target.
276     return nullptr;
277   }
278 }
279 
FindMethodIndexIn(ArtMethod * method,const DexFile & dex_file,uint32_t name_and_signature_index)280 static uint32_t FindMethodIndexIn(ArtMethod* method,
281                                   const DexFile& dex_file,
282                                   uint32_t name_and_signature_index)
283     REQUIRES_SHARED(Locks::mutator_lock_) {
284   if (IsSameDexFile(*method->GetDexFile(), dex_file)) {
285     return method->GetDexMethodIndex();
286   } else {
287     return method->FindDexMethodIndexInOtherDexFile(dex_file, name_and_signature_index);
288   }
289 }
290 
FindClassIndexIn(ObjPtr<mirror::Class> cls,const DexCompilationUnit & compilation_unit)291 static dex::TypeIndex FindClassIndexIn(ObjPtr<mirror::Class> cls,
292                                        const DexCompilationUnit& compilation_unit)
293     REQUIRES_SHARED(Locks::mutator_lock_) {
294   const DexFile& dex_file = *compilation_unit.GetDexFile();
295   dex::TypeIndex index;
296   if (cls->GetDexCache() == nullptr) {
297     DCHECK(cls->IsArrayClass()) << cls->PrettyClass();
298     index = cls->FindTypeIndexInOtherDexFile(dex_file);
299   } else if (!cls->GetDexTypeIndex().IsValid()) {
300     DCHECK(cls->IsProxyClass()) << cls->PrettyClass();
301     // TODO: deal with proxy classes.
302   } else if (IsSameDexFile(cls->GetDexFile(), dex_file)) {
303     DCHECK_EQ(cls->GetDexCache(), compilation_unit.GetDexCache().Get());
304     index = cls->GetDexTypeIndex();
305   } else {
306     index = cls->FindTypeIndexInOtherDexFile(dex_file);
307     // We cannot guarantee the entry will resolve to the same class,
308     // as there may be different class loaders. So only return the index if it's
309     // the right class already resolved with the class loader.
310     if (index.IsValid()) {
311       ObjPtr<mirror::Class> resolved = compilation_unit.GetClassLinker()->LookupResolvedType(
312           index, compilation_unit.GetDexCache().Get(), compilation_unit.GetClassLoader().Get());
313       if (resolved != cls) {
314         index = dex::TypeIndex::Invalid();
315       }
316     }
317   }
318 
319   return index;
320 }
321 
322 class ScopedProfilingInfoInlineUse {
323  public:
ScopedProfilingInfoInlineUse(ArtMethod * method,Thread * self)324   explicit ScopedProfilingInfoInlineUse(ArtMethod* method, Thread* self)
325       : method_(method),
326         self_(self),
327         // Fetch the profiling info ahead of using it. If it's null when fetching,
328         // we should not call JitCodeCache::DoneInlining.
329         profiling_info_(
330             Runtime::Current()->GetJit()->GetCodeCache()->NotifyCompilerUse(method, self)) {
331   }
332 
~ScopedProfilingInfoInlineUse()333   ~ScopedProfilingInfoInlineUse() {
334     if (profiling_info_ != nullptr) {
335       PointerSize pointer_size = Runtime::Current()->GetClassLinker()->GetImagePointerSize();
336       DCHECK_EQ(profiling_info_, method_->GetProfilingInfo(pointer_size));
337       Runtime::Current()->GetJit()->GetCodeCache()->DoneCompilerUse(method_, self_);
338     }
339   }
340 
GetProfilingInfo() const341   ProfilingInfo* GetProfilingInfo() const { return profiling_info_; }
342 
343  private:
344   ArtMethod* const method_;
345   Thread* const self_;
346   ProfilingInfo* const profiling_info_;
347 };
348 
GetInlineCacheType(const Handle<mirror::ObjectArray<mirror::Class>> & classes)349 HInliner::InlineCacheType HInliner::GetInlineCacheType(
350     const Handle<mirror::ObjectArray<mirror::Class>>& classes)
351   REQUIRES_SHARED(Locks::mutator_lock_) {
352   uint8_t number_of_types = 0;
353   for (; number_of_types < InlineCache::kIndividualCacheSize; ++number_of_types) {
354     if (classes->Get(number_of_types) == nullptr) {
355       break;
356     }
357   }
358 
359   if (number_of_types == 0) {
360     return kInlineCacheUninitialized;
361   } else if (number_of_types == 1) {
362     return kInlineCacheMonomorphic;
363   } else if (number_of_types == InlineCache::kIndividualCacheSize) {
364     return kInlineCacheMegamorphic;
365   } else {
366     return kInlineCachePolymorphic;
367   }
368 }
369 
GetMonomorphicType(Handle<mirror::ObjectArray<mirror::Class>> classes)370 static ObjPtr<mirror::Class> GetMonomorphicType(Handle<mirror::ObjectArray<mirror::Class>> classes)
371     REQUIRES_SHARED(Locks::mutator_lock_) {
372   DCHECK(classes->Get(0) != nullptr);
373   return classes->Get(0);
374 }
375 
TryCHADevirtualization(ArtMethod * resolved_method)376 ArtMethod* HInliner::TryCHADevirtualization(ArtMethod* resolved_method) {
377   if (!resolved_method->HasSingleImplementation()) {
378     return nullptr;
379   }
380   if (Runtime::Current()->IsAotCompiler()) {
381     // No CHA-based devirtulization for AOT compiler (yet).
382     return nullptr;
383   }
384   if (Runtime::Current()->IsZygote()) {
385     // No CHA-based devirtulization for Zygote, as it compiles with
386     // offline information.
387     return nullptr;
388   }
389   if (outermost_graph_->IsCompilingOsr()) {
390     // We do not support HDeoptimize in OSR methods.
391     return nullptr;
392   }
393   PointerSize pointer_size = caller_compilation_unit_.GetClassLinker()->GetImagePointerSize();
394   ArtMethod* single_impl = resolved_method->GetSingleImplementation(pointer_size);
395   if (single_impl == nullptr) {
396     return nullptr;
397   }
398   if (single_impl->IsProxyMethod()) {
399     // Proxy method is a generic invoker that's not worth
400     // devirtualizing/inlining. It also causes issues when the proxy
401     // method is in another dex file if we try to rewrite invoke-interface to
402     // invoke-virtual because a proxy method doesn't have a real dex file.
403     return nullptr;
404   }
405   if (!single_impl->GetDeclaringClass()->IsResolved()) {
406     // There's a race with the class loading, which updates the CHA info
407     // before setting the class to resolved. So we just bail for this
408     // rare occurence.
409     return nullptr;
410   }
411   return single_impl;
412 }
413 
IsMethodUnverified(const CompilerOptions & compiler_options,ArtMethod * method)414 static bool IsMethodUnverified(const CompilerOptions& compiler_options, ArtMethod* method)
415     REQUIRES_SHARED(Locks::mutator_lock_) {
416   if (!method->GetDeclaringClass()->IsVerified()) {
417     if (compiler_options.IsJitCompiler()) {
418       // We're at runtime, we know this is cold code if the class
419       // is not verified, so don't bother analyzing.
420       return true;
421     }
422     uint16_t class_def_idx = method->GetDeclaringClass()->GetDexClassDefIndex();
423     if (!compiler_options.IsMethodVerifiedWithoutFailures(method->GetDexMethodIndex(),
424                                                           class_def_idx,
425                                                           *method->GetDexFile())) {
426       // Method has soft or hard failures, don't analyze.
427       return true;
428     }
429   }
430   return false;
431 }
432 
AlwaysThrows(const CompilerOptions & compiler_options,ArtMethod * method)433 static bool AlwaysThrows(const CompilerOptions& compiler_options, ArtMethod* method)
434     REQUIRES_SHARED(Locks::mutator_lock_) {
435   DCHECK(method != nullptr);
436   // Skip non-compilable and unverified methods.
437   if (!method->IsCompilable() || IsMethodUnverified(compiler_options, method)) {
438     return false;
439   }
440   // Skip native methods, methods with try blocks, and methods that are too large.
441   CodeItemDataAccessor accessor(method->DexInstructionData());
442   if (!accessor.HasCodeItem() ||
443       accessor.TriesSize() != 0 ||
444       accessor.InsnsSizeInCodeUnits() > kMaximumNumberOfTotalInstructions) {
445     return false;
446   }
447   // Scan for exits.
448   bool throw_seen = false;
449   for (const DexInstructionPcPair& pair : accessor) {
450     switch (pair.Inst().Opcode()) {
451       case Instruction::RETURN:
452       case Instruction::RETURN_VOID:
453       case Instruction::RETURN_WIDE:
454       case Instruction::RETURN_OBJECT:
455       case Instruction::RETURN_VOID_NO_BARRIER:
456         return false;  // found regular control flow back
457       case Instruction::THROW:
458         throw_seen = true;
459         break;
460       default:
461         break;
462     }
463   }
464   return throw_seen;
465 }
466 
FindActualCallTarget(HInvoke * invoke_instruction,bool * cha_devirtualize)467 ArtMethod* HInliner::FindActualCallTarget(HInvoke* invoke_instruction, bool* cha_devirtualize) {
468   ArtMethod* resolved_method = invoke_instruction->GetResolvedMethod();
469   DCHECK(resolved_method != nullptr);
470 
471   ArtMethod* actual_method = nullptr;
472   if (invoke_instruction->IsInvokeStaticOrDirect()) {
473     actual_method = resolved_method;
474   } else {
475     // Check if we can statically find the method.
476     actual_method = FindVirtualOrInterfaceTarget(invoke_instruction, resolved_method);
477   }
478 
479   if (actual_method == nullptr) {
480     ArtMethod* method = TryCHADevirtualization(resolved_method);
481     if (method != nullptr) {
482       *cha_devirtualize = true;
483       actual_method = method;
484       LOG_NOTE() << "Try CHA-based inlining of " << actual_method->PrettyMethod();
485     }
486   }
487 
488   return actual_method;
489 }
490 
TryInline(HInvoke * invoke_instruction)491 bool HInliner::TryInline(HInvoke* invoke_instruction) {
492   MaybeRecordStat(stats_, MethodCompilationStat::kTryInline);
493 
494   // Don't bother to move further if we know the method is unresolved or the invocation is
495   // polymorphic (invoke-{polymorphic,custom}).
496   if (invoke_instruction->IsInvokeUnresolved()) {
497     MaybeRecordStat(stats_, MethodCompilationStat::kNotInlinedUnresolved);
498     return false;
499   } else if (invoke_instruction->IsInvokePolymorphic()) {
500     MaybeRecordStat(stats_, MethodCompilationStat::kNotInlinedPolymorphic);
501     return false;
502   } else if (invoke_instruction->IsInvokeCustom()) {
503     MaybeRecordStat(stats_, MethodCompilationStat::kNotInlinedCustom);
504     return false;
505   }
506 
507   ScopedObjectAccess soa(Thread::Current());
508   uint32_t method_index = invoke_instruction->GetDexMethodIndex();
509   const DexFile& caller_dex_file = *caller_compilation_unit_.GetDexFile();
510   LOG_TRY() << caller_dex_file.PrettyMethod(method_index);
511 
512   ArtMethod* resolved_method = invoke_instruction->GetResolvedMethod();
513   if (resolved_method == nullptr) {
514     DCHECK(invoke_instruction->IsInvokeStaticOrDirect());
515     DCHECK(invoke_instruction->AsInvokeStaticOrDirect()->IsStringInit());
516     LOG_FAIL_NO_STAT() << "Not inlining a String.<init> method";
517     return false;
518   }
519 
520   bool cha_devirtualize = false;
521   ArtMethod* actual_method = FindActualCallTarget(invoke_instruction, &cha_devirtualize);
522 
523   // If we didn't find a method, see if we can inline from the inline caches.
524   if (actual_method == nullptr) {
525     DCHECK(!invoke_instruction->IsInvokeStaticOrDirect());
526 
527     return TryInlineFromInlineCache(caller_dex_file, invoke_instruction, resolved_method);
528   }
529 
530   // Single target.
531   bool result = TryInlineAndReplace(invoke_instruction,
532                                     actual_method,
533                                     ReferenceTypeInfo::CreateInvalid(),
534                                     /* do_rtp= */ true,
535                                     cha_devirtualize);
536   if (result) {
537     // Successfully inlined.
538     if (!invoke_instruction->IsInvokeStaticOrDirect()) {
539       if (cha_devirtualize) {
540         // Add dependency due to devirtualization. We've assumed resolved_method
541         // has single implementation.
542         outermost_graph_->AddCHASingleImplementationDependency(resolved_method);
543         MaybeRecordStat(stats_, MethodCompilationStat::kCHAInline);
544       } else {
545         MaybeRecordStat(stats_, MethodCompilationStat::kInlinedInvokeVirtualOrInterface);
546       }
547     }
548   } else if (!cha_devirtualize && AlwaysThrows(codegen_->GetCompilerOptions(), actual_method)) {
549     // Set always throws property for non-inlined method call with single target
550     // (unless it was obtained through CHA, because that would imply we have
551     // to add the CHA dependency, which seems not worth it).
552     invoke_instruction->SetAlwaysThrows(true);
553   }
554   return result;
555 }
556 
AllocateInlineCacheHolder(const DexCompilationUnit & compilation_unit,StackHandleScope<1> * hs)557 static Handle<mirror::ObjectArray<mirror::Class>> AllocateInlineCacheHolder(
558     const DexCompilationUnit& compilation_unit,
559     StackHandleScope<1>* hs)
560     REQUIRES_SHARED(Locks::mutator_lock_) {
561   Thread* self = Thread::Current();
562   ClassLinker* class_linker = compilation_unit.GetClassLinker();
563   Handle<mirror::ObjectArray<mirror::Class>> inline_cache = hs->NewHandle(
564       mirror::ObjectArray<mirror::Class>::Alloc(
565           self,
566           GetClassRoot<mirror::ObjectArray<mirror::Class>>(class_linker),
567           InlineCache::kIndividualCacheSize));
568   if (inline_cache == nullptr) {
569     // We got an OOME. Just clear the exception, and don't inline.
570     DCHECK(self->IsExceptionPending());
571     self->ClearException();
572     VLOG(compiler) << "Out of memory in the compiler when trying to inline";
573   }
574   return inline_cache;
575 }
576 
UseOnlyPolymorphicInliningWithNoDeopt()577 bool HInliner::UseOnlyPolymorphicInliningWithNoDeopt() {
578   // If we are compiling AOT or OSR, pretend the call using inline caches is polymorphic and
579   // do not generate a deopt.
580   //
581   // For AOT:
582   //    Generating a deopt does not ensure that we will actually capture the new types;
583   //    and the danger is that we could be stuck in a loop with "forever" deoptimizations.
584   //    Take for example the following scenario:
585   //      - we capture the inline cache in one run
586   //      - the next run, we deoptimize because we miss a type check, but the method
587   //        never becomes hot again
588   //    In this case, the inline cache will not be updated in the profile and the AOT code
589   //    will keep deoptimizing.
590   //    Another scenario is if we use profile compilation for a process which is not allowed
591   //    to JIT (e.g. system server). If we deoptimize we will run interpreted code for the
592   //    rest of the lifetime.
593   // TODO(calin):
594   //    This is a compromise because we will most likely never update the inline cache
595   //    in the profile (unless there's another reason to deopt). So we might be stuck with
596   //    a sub-optimal inline cache.
597   //    We could be smarter when capturing inline caches to mitigate this.
598   //    (e.g. by having different thresholds for new and old methods).
599   //
600   // For OSR:
601   //     We may come from the interpreter and it may have seen different receiver types.
602   return Runtime::Current()->IsAotCompiler() || outermost_graph_->IsCompilingOsr();
603 }
TryInlineFromInlineCache(const DexFile & caller_dex_file,HInvoke * invoke_instruction,ArtMethod * resolved_method)604 bool HInliner::TryInlineFromInlineCache(const DexFile& caller_dex_file,
605                                         HInvoke* invoke_instruction,
606                                         ArtMethod* resolved_method)
607     REQUIRES_SHARED(Locks::mutator_lock_) {
608   if (Runtime::Current()->IsAotCompiler() && !kUseAOTInlineCaches) {
609     return false;
610   }
611 
612   StackHandleScope<1> hs(Thread::Current());
613   Handle<mirror::ObjectArray<mirror::Class>> inline_cache;
614   // The Zygote JIT compiles based on a profile, so we shouldn't use runtime inline caches
615   // for it.
616   InlineCacheType inline_cache_type =
617       (Runtime::Current()->IsAotCompiler() || Runtime::Current()->IsZygote())
618           ? GetInlineCacheAOT(caller_dex_file, invoke_instruction, &hs, &inline_cache)
619           : GetInlineCacheJIT(invoke_instruction, &hs, &inline_cache);
620 
621   switch (inline_cache_type) {
622     case kInlineCacheNoData: {
623       LOG_FAIL_NO_STAT()
624           << "No inline cache information for call to "
625           << caller_dex_file.PrettyMethod(invoke_instruction->GetDexMethodIndex());
626       return false;
627     }
628 
629     case kInlineCacheUninitialized: {
630       LOG_FAIL_NO_STAT()
631           << "Interface or virtual call to "
632           << caller_dex_file.PrettyMethod(invoke_instruction->GetDexMethodIndex())
633           << " is not hit and not inlined";
634       return false;
635     }
636 
637     case kInlineCacheMonomorphic: {
638       MaybeRecordStat(stats_, MethodCompilationStat::kMonomorphicCall);
639       if (UseOnlyPolymorphicInliningWithNoDeopt()) {
640         return TryInlinePolymorphicCall(invoke_instruction, resolved_method, inline_cache);
641       } else {
642         return TryInlineMonomorphicCall(invoke_instruction, resolved_method, inline_cache);
643       }
644     }
645 
646     case kInlineCachePolymorphic: {
647       MaybeRecordStat(stats_, MethodCompilationStat::kPolymorphicCall);
648       return TryInlinePolymorphicCall(invoke_instruction, resolved_method, inline_cache);
649     }
650 
651     case kInlineCacheMegamorphic: {
652       LOG_FAIL_NO_STAT()
653           << "Interface or virtual call to "
654           << caller_dex_file.PrettyMethod(invoke_instruction->GetDexMethodIndex())
655           << " is megamorphic and not inlined";
656       MaybeRecordStat(stats_, MethodCompilationStat::kMegamorphicCall);
657       return false;
658     }
659 
660     case kInlineCacheMissingTypes: {
661       LOG_FAIL_NO_STAT()
662           << "Interface or virtual call to "
663           << caller_dex_file.PrettyMethod(invoke_instruction->GetDexMethodIndex())
664           << " is missing types and not inlined";
665       return false;
666     }
667   }
668   UNREACHABLE();
669 }
670 
GetInlineCacheJIT(HInvoke * invoke_instruction,StackHandleScope<1> * hs,Handle<mirror::ObjectArray<mirror::Class>> * inline_cache)671 HInliner::InlineCacheType HInliner::GetInlineCacheJIT(
672     HInvoke* invoke_instruction,
673     StackHandleScope<1>* hs,
674     /*out*/Handle<mirror::ObjectArray<mirror::Class>>* inline_cache)
675     REQUIRES_SHARED(Locks::mutator_lock_) {
676   DCHECK(codegen_->GetCompilerOptions().IsJitCompiler());
677 
678   ArtMethod* caller = graph_->GetArtMethod();
679   // Under JIT, we should always know the caller.
680   DCHECK(caller != nullptr);
681   ScopedProfilingInfoInlineUse spiis(caller, Thread::Current());
682   ProfilingInfo* profiling_info = spiis.GetProfilingInfo();
683 
684   if (profiling_info == nullptr) {
685     return kInlineCacheNoData;
686   }
687 
688   *inline_cache = AllocateInlineCacheHolder(caller_compilation_unit_, hs);
689   if (inline_cache->Get() == nullptr) {
690     // We can't extract any data if we failed to allocate;
691     return kInlineCacheNoData;
692   } else {
693     Runtime::Current()->GetJit()->GetCodeCache()->CopyInlineCacheInto(
694         *profiling_info->GetInlineCache(invoke_instruction->GetDexPc()),
695         *inline_cache);
696     return GetInlineCacheType(*inline_cache);
697   }
698 }
699 
GetInlineCacheAOT(const DexFile & caller_dex_file,HInvoke * invoke_instruction,StackHandleScope<1> * hs,Handle<mirror::ObjectArray<mirror::Class>> * inline_cache)700 HInliner::InlineCacheType HInliner::GetInlineCacheAOT(
701     const DexFile& caller_dex_file,
702     HInvoke* invoke_instruction,
703     StackHandleScope<1>* hs,
704     /*out*/Handle<mirror::ObjectArray<mirror::Class>>* inline_cache)
705     REQUIRES_SHARED(Locks::mutator_lock_) {
706   const ProfileCompilationInfo* pci = codegen_->GetCompilerOptions().GetProfileCompilationInfo();
707   if (pci == nullptr) {
708     return kInlineCacheNoData;
709   }
710 
711   std::unique_ptr<ProfileCompilationInfo::OfflineProfileMethodInfo> offline_profile =
712       pci->GetHotMethodInfo(MethodReference(
713           &caller_dex_file, caller_compilation_unit_.GetDexMethodIndex()));
714   if (offline_profile == nullptr) {
715     return kInlineCacheNoData;  // no profile information for this invocation.
716   }
717 
718   *inline_cache = AllocateInlineCacheHolder(caller_compilation_unit_, hs);
719   if (inline_cache == nullptr) {
720     // We can't extract any data if we failed to allocate;
721     return kInlineCacheNoData;
722   } else {
723     return ExtractClassesFromOfflineProfile(invoke_instruction,
724                                             *(offline_profile.get()),
725                                             *inline_cache);
726   }
727 }
728 
ExtractClassesFromOfflineProfile(const HInvoke * invoke_instruction,const ProfileCompilationInfo::OfflineProfileMethodInfo & offline_profile,Handle<mirror::ObjectArray<mirror::Class>> inline_cache)729 HInliner::InlineCacheType HInliner::ExtractClassesFromOfflineProfile(
730     const HInvoke* invoke_instruction,
731     const ProfileCompilationInfo::OfflineProfileMethodInfo& offline_profile,
732     /*out*/Handle<mirror::ObjectArray<mirror::Class>> inline_cache)
733     REQUIRES_SHARED(Locks::mutator_lock_) {
734   const auto it = offline_profile.inline_caches->find(invoke_instruction->GetDexPc());
735   if (it == offline_profile.inline_caches->end()) {
736     return kInlineCacheUninitialized;
737   }
738 
739   const ProfileCompilationInfo::DexPcData& dex_pc_data = it->second;
740 
741   if (dex_pc_data.is_missing_types) {
742     return kInlineCacheMissingTypes;
743   }
744   if (dex_pc_data.is_megamorphic) {
745     return kInlineCacheMegamorphic;
746   }
747 
748   DCHECK_LE(dex_pc_data.classes.size(), InlineCache::kIndividualCacheSize);
749   Thread* self = Thread::Current();
750   // We need to resolve the class relative to the containing dex file.
751   // So first, build a mapping from the index of dex file in the profile to
752   // its dex cache. This will avoid repeating the lookup when walking over
753   // the inline cache types.
754   std::vector<ObjPtr<mirror::DexCache>> dex_profile_index_to_dex_cache(
755         offline_profile.dex_references.size());
756   for (size_t i = 0; i < offline_profile.dex_references.size(); i++) {
757     bool found = false;
758     for (const DexFile* dex_file : codegen_->GetCompilerOptions().GetDexFilesForOatFile()) {
759       if (offline_profile.dex_references[i].MatchesDex(dex_file)) {
760         dex_profile_index_to_dex_cache[i] =
761             caller_compilation_unit_.GetClassLinker()->FindDexCache(self, *dex_file);
762         found = true;
763       }
764     }
765     if (!found) {
766       VLOG(compiler) << "Could not find profiled dex file: " << offline_profile.dex_references[i];
767       return kInlineCacheMissingTypes;
768     }
769   }
770 
771   // Walk over the classes and resolve them. If we cannot find a type we return
772   // kInlineCacheMissingTypes.
773   int ic_index = 0;
774   for (const ProfileCompilationInfo::ClassReference& class_ref : dex_pc_data.classes) {
775     ObjPtr<mirror::DexCache> dex_cache =
776         dex_profile_index_to_dex_cache[class_ref.dex_profile_index];
777     DCHECK(dex_cache != nullptr);
778 
779     if (!dex_cache->GetDexFile()->IsTypeIndexValid(class_ref.type_index)) {
780       VLOG(compiler) << "Profile data corrupt: type index " << class_ref.type_index
781             << "is invalid in location" << dex_cache->GetDexFile()->GetLocation();
782       return kInlineCacheNoData;
783     }
784     ObjPtr<mirror::Class> clazz = caller_compilation_unit_.GetClassLinker()->LookupResolvedType(
785           class_ref.type_index,
786           dex_cache,
787           caller_compilation_unit_.GetClassLoader().Get());
788     if (clazz != nullptr) {
789       inline_cache->Set(ic_index++, clazz);
790     } else {
791       VLOG(compiler) << "Could not resolve class from inline cache in AOT mode "
792           << caller_compilation_unit_.GetDexFile()->PrettyMethod(
793               invoke_instruction->GetDexMethodIndex()) << " : "
794           << caller_compilation_unit_
795               .GetDexFile()->StringByTypeIdx(class_ref.type_index);
796       return kInlineCacheMissingTypes;
797     }
798   }
799   return GetInlineCacheType(inline_cache);
800 }
801 
BuildGetReceiverClass(ClassLinker * class_linker,HInstruction * receiver,uint32_t dex_pc) const802 HInstanceFieldGet* HInliner::BuildGetReceiverClass(ClassLinker* class_linker,
803                                                    HInstruction* receiver,
804                                                    uint32_t dex_pc) const {
805   ArtField* field = GetClassRoot<mirror::Object>(class_linker)->GetInstanceField(0);
806   DCHECK_EQ(std::string(field->GetName()), "shadow$_klass_");
807   HInstanceFieldGet* result = new (graph_->GetAllocator()) HInstanceFieldGet(
808       receiver,
809       field,
810       DataType::Type::kReference,
811       field->GetOffset(),
812       field->IsVolatile(),
813       field->GetDexFieldIndex(),
814       field->GetDeclaringClass()->GetDexClassDefIndex(),
815       *field->GetDexFile(),
816       dex_pc);
817   // The class of a field is effectively final, and does not have any memory dependencies.
818   result->SetSideEffects(SideEffects::None());
819   return result;
820 }
821 
ResolveMethodFromInlineCache(Handle<mirror::Class> klass,ArtMethod * resolved_method,HInstruction * invoke_instruction,PointerSize pointer_size)822 static ArtMethod* ResolveMethodFromInlineCache(Handle<mirror::Class> klass,
823                                                ArtMethod* resolved_method,
824                                                HInstruction* invoke_instruction,
825                                                PointerSize pointer_size)
826     REQUIRES_SHARED(Locks::mutator_lock_) {
827   if (Runtime::Current()->IsAotCompiler()) {
828     // We can get unrelated types when working with profiles (corruption,
829     // systme updates, or anyone can write to it). So first check if the class
830     // actually implements the declaring class of the method that is being
831     // called in bytecode.
832     // Note: the lookup methods used below require to have assignable types.
833     if (!resolved_method->GetDeclaringClass()->IsAssignableFrom(klass.Get())) {
834       return nullptr;
835     }
836   }
837 
838   if (invoke_instruction->IsInvokeInterface()) {
839     resolved_method = klass->FindVirtualMethodForInterface(resolved_method, pointer_size);
840   } else {
841     DCHECK(invoke_instruction->IsInvokeVirtual());
842     resolved_method = klass->FindVirtualMethodForVirtual(resolved_method, pointer_size);
843   }
844   DCHECK(resolved_method != nullptr);
845   return resolved_method;
846 }
847 
TryInlineMonomorphicCall(HInvoke * invoke_instruction,ArtMethod * resolved_method,Handle<mirror::ObjectArray<mirror::Class>> classes)848 bool HInliner::TryInlineMonomorphicCall(HInvoke* invoke_instruction,
849                                         ArtMethod* resolved_method,
850                                         Handle<mirror::ObjectArray<mirror::Class>> classes) {
851   DCHECK(invoke_instruction->IsInvokeVirtual() || invoke_instruction->IsInvokeInterface())
852       << invoke_instruction->DebugName();
853 
854   dex::TypeIndex class_index = FindClassIndexIn(
855       GetMonomorphicType(classes), caller_compilation_unit_);
856   if (!class_index.IsValid()) {
857     LOG_FAIL(stats_, MethodCompilationStat::kNotInlinedDexCache)
858         << "Call to " << ArtMethod::PrettyMethod(resolved_method)
859         << " from inline cache is not inlined because its class is not"
860         << " accessible to the caller";
861     return false;
862   }
863 
864   ClassLinker* class_linker = caller_compilation_unit_.GetClassLinker();
865   PointerSize pointer_size = class_linker->GetImagePointerSize();
866   Handle<mirror::Class> monomorphic_type =
867       graph_->GetHandleCache()->NewHandle(GetMonomorphicType(classes));
868   resolved_method = ResolveMethodFromInlineCache(
869       monomorphic_type, resolved_method, invoke_instruction, pointer_size);
870 
871   LOG_NOTE() << "Try inline monomorphic call to " << resolved_method->PrettyMethod();
872   if (resolved_method == nullptr) {
873     // Bogus AOT profile, bail.
874     DCHECK(Runtime::Current()->IsAotCompiler());
875     return false;
876   }
877 
878   HInstruction* receiver = invoke_instruction->InputAt(0);
879   HInstruction* cursor = invoke_instruction->GetPrevious();
880   HBasicBlock* bb_cursor = invoke_instruction->GetBlock();
881   if (!TryInlineAndReplace(invoke_instruction,
882                            resolved_method,
883                            ReferenceTypeInfo::Create(monomorphic_type, /* is_exact= */ true),
884                            /* do_rtp= */ false,
885                            /* cha_devirtualize= */ false)) {
886     return false;
887   }
888 
889   // We successfully inlined, now add a guard.
890   AddTypeGuard(receiver,
891                cursor,
892                bb_cursor,
893                class_index,
894                monomorphic_type,
895                invoke_instruction,
896                /* with_deoptimization= */ true);
897 
898   // Run type propagation to get the guard typed, and eventually propagate the
899   // type of the receiver.
900   ReferenceTypePropagation rtp_fixup(graph_,
901                                      outer_compilation_unit_.GetClassLoader(),
902                                      outer_compilation_unit_.GetDexCache(),
903                                      /* is_first_run= */ false);
904   rtp_fixup.Run();
905 
906   MaybeRecordStat(stats_, MethodCompilationStat::kInlinedMonomorphicCall);
907   return true;
908 }
909 
AddCHAGuard(HInstruction * invoke_instruction,uint32_t dex_pc,HInstruction * cursor,HBasicBlock * bb_cursor)910 void HInliner::AddCHAGuard(HInstruction* invoke_instruction,
911                            uint32_t dex_pc,
912                            HInstruction* cursor,
913                            HBasicBlock* bb_cursor) {
914   HShouldDeoptimizeFlag* deopt_flag = new (graph_->GetAllocator())
915       HShouldDeoptimizeFlag(graph_->GetAllocator(), dex_pc);
916   HInstruction* compare = new (graph_->GetAllocator()) HNotEqual(
917       deopt_flag, graph_->GetIntConstant(0, dex_pc));
918   HInstruction* deopt = new (graph_->GetAllocator()) HDeoptimize(
919       graph_->GetAllocator(), compare, DeoptimizationKind::kCHA, dex_pc);
920 
921   if (cursor != nullptr) {
922     bb_cursor->InsertInstructionAfter(deopt_flag, cursor);
923   } else {
924     bb_cursor->InsertInstructionBefore(deopt_flag, bb_cursor->GetFirstInstruction());
925   }
926   bb_cursor->InsertInstructionAfter(compare, deopt_flag);
927   bb_cursor->InsertInstructionAfter(deopt, compare);
928 
929   // Add receiver as input to aid CHA guard optimization later.
930   deopt_flag->AddInput(invoke_instruction->InputAt(0));
931   DCHECK_EQ(deopt_flag->InputCount(), 1u);
932   deopt->CopyEnvironmentFrom(invoke_instruction->GetEnvironment());
933   outermost_graph_->IncrementNumberOfCHAGuards();
934 }
935 
AddTypeGuard(HInstruction * receiver,HInstruction * cursor,HBasicBlock * bb_cursor,dex::TypeIndex class_index,Handle<mirror::Class> klass,HInstruction * invoke_instruction,bool with_deoptimization)936 HInstruction* HInliner::AddTypeGuard(HInstruction* receiver,
937                                      HInstruction* cursor,
938                                      HBasicBlock* bb_cursor,
939                                      dex::TypeIndex class_index,
940                                      Handle<mirror::Class> klass,
941                                      HInstruction* invoke_instruction,
942                                      bool with_deoptimization) {
943   ClassLinker* class_linker = caller_compilation_unit_.GetClassLinker();
944   HInstanceFieldGet* receiver_class = BuildGetReceiverClass(
945       class_linker, receiver, invoke_instruction->GetDexPc());
946   if (cursor != nullptr) {
947     bb_cursor->InsertInstructionAfter(receiver_class, cursor);
948   } else {
949     bb_cursor->InsertInstructionBefore(receiver_class, bb_cursor->GetFirstInstruction());
950   }
951 
952   const DexFile& caller_dex_file = *caller_compilation_unit_.GetDexFile();
953   bool is_referrer;
954   ArtMethod* outermost_art_method = outermost_graph_->GetArtMethod();
955   if (outermost_art_method == nullptr) {
956     DCHECK(Runtime::Current()->IsAotCompiler());
957     // We are in AOT mode and we don't have an ART method to determine
958     // if the inlined method belongs to the referrer. Assume it doesn't.
959     is_referrer = false;
960   } else {
961     is_referrer = klass.Get() == outermost_art_method->GetDeclaringClass();
962   }
963 
964   // Note that we will just compare the classes, so we don't need Java semantics access checks.
965   // Note that the type index and the dex file are relative to the method this type guard is
966   // inlined into.
967   HLoadClass* load_class = new (graph_->GetAllocator()) HLoadClass(graph_->GetCurrentMethod(),
968                                                                    class_index,
969                                                                    caller_dex_file,
970                                                                    klass,
971                                                                    is_referrer,
972                                                                    invoke_instruction->GetDexPc(),
973                                                                    /* needs_access_check= */ false);
974   HLoadClass::LoadKind kind = HSharpening::ComputeLoadClassKind(
975       load_class, codegen_, caller_compilation_unit_);
976   DCHECK(kind != HLoadClass::LoadKind::kInvalid)
977       << "We should always be able to reference a class for inline caches";
978   // Load kind must be set before inserting the instruction into the graph.
979   load_class->SetLoadKind(kind);
980   bb_cursor->InsertInstructionAfter(load_class, receiver_class);
981   // In AOT mode, we will most likely load the class from BSS, which will involve a call
982   // to the runtime. In this case, the load instruction will need an environment so copy
983   // it from the invoke instruction.
984   if (load_class->NeedsEnvironment()) {
985     DCHECK(Runtime::Current()->IsAotCompiler());
986     load_class->CopyEnvironmentFrom(invoke_instruction->GetEnvironment());
987   }
988 
989   HNotEqual* compare = new (graph_->GetAllocator()) HNotEqual(load_class, receiver_class);
990   bb_cursor->InsertInstructionAfter(compare, load_class);
991   if (with_deoptimization) {
992     HDeoptimize* deoptimize = new (graph_->GetAllocator()) HDeoptimize(
993         graph_->GetAllocator(),
994         compare,
995         receiver,
996         Runtime::Current()->IsAotCompiler()
997             ? DeoptimizationKind::kAotInlineCache
998             : DeoptimizationKind::kJitInlineCache,
999         invoke_instruction->GetDexPc());
1000     bb_cursor->InsertInstructionAfter(deoptimize, compare);
1001     deoptimize->CopyEnvironmentFrom(invoke_instruction->GetEnvironment());
1002     DCHECK_EQ(invoke_instruction->InputAt(0), receiver);
1003     receiver->ReplaceUsesDominatedBy(deoptimize, deoptimize);
1004     deoptimize->SetReferenceTypeInfo(receiver->GetReferenceTypeInfo());
1005   }
1006   return compare;
1007 }
1008 
TryInlinePolymorphicCall(HInvoke * invoke_instruction,ArtMethod * resolved_method,Handle<mirror::ObjectArray<mirror::Class>> classes)1009 bool HInliner::TryInlinePolymorphicCall(HInvoke* invoke_instruction,
1010                                         ArtMethod* resolved_method,
1011                                         Handle<mirror::ObjectArray<mirror::Class>> classes) {
1012   DCHECK(invoke_instruction->IsInvokeVirtual() || invoke_instruction->IsInvokeInterface())
1013       << invoke_instruction->DebugName();
1014 
1015   if (TryInlinePolymorphicCallToSameTarget(invoke_instruction, resolved_method, classes)) {
1016     return true;
1017   }
1018 
1019   ClassLinker* class_linker = caller_compilation_unit_.GetClassLinker();
1020   PointerSize pointer_size = class_linker->GetImagePointerSize();
1021 
1022   bool all_targets_inlined = true;
1023   bool one_target_inlined = false;
1024   for (size_t i = 0; i < InlineCache::kIndividualCacheSize; ++i) {
1025     if (classes->Get(i) == nullptr) {
1026       break;
1027     }
1028     ArtMethod* method = nullptr;
1029 
1030     Handle<mirror::Class> handle = graph_->GetHandleCache()->NewHandle(classes->Get(i));
1031     method = ResolveMethodFromInlineCache(
1032         handle, resolved_method, invoke_instruction, pointer_size);
1033     if (method == nullptr) {
1034       DCHECK(Runtime::Current()->IsAotCompiler());
1035       // AOT profile is bogus. This loop expects to iterate over all entries,
1036       // so just just continue.
1037       all_targets_inlined = false;
1038       continue;
1039     }
1040 
1041     HInstruction* receiver = invoke_instruction->InputAt(0);
1042     HInstruction* cursor = invoke_instruction->GetPrevious();
1043     HBasicBlock* bb_cursor = invoke_instruction->GetBlock();
1044 
1045     dex::TypeIndex class_index = FindClassIndexIn(handle.Get(), caller_compilation_unit_);
1046     HInstruction* return_replacement = nullptr;
1047     LOG_NOTE() << "Try inline polymorphic call to " << method->PrettyMethod();
1048     if (!class_index.IsValid() ||
1049         !TryBuildAndInline(invoke_instruction,
1050                            method,
1051                            ReferenceTypeInfo::Create(handle, /* is_exact= */ true),
1052                            &return_replacement)) {
1053       all_targets_inlined = false;
1054     } else {
1055       one_target_inlined = true;
1056 
1057       LOG_SUCCESS() << "Polymorphic call to " << ArtMethod::PrettyMethod(resolved_method)
1058                     << " has inlined " << ArtMethod::PrettyMethod(method);
1059 
1060       // If we have inlined all targets before, and this receiver is the last seen,
1061       // we deoptimize instead of keeping the original invoke instruction.
1062       bool deoptimize = !UseOnlyPolymorphicInliningWithNoDeopt() &&
1063           all_targets_inlined &&
1064           (i != InlineCache::kIndividualCacheSize - 1) &&
1065           (classes->Get(i + 1) == nullptr);
1066 
1067       HInstruction* compare = AddTypeGuard(receiver,
1068                                            cursor,
1069                                            bb_cursor,
1070                                            class_index,
1071                                            handle,
1072                                            invoke_instruction,
1073                                            deoptimize);
1074       if (deoptimize) {
1075         if (return_replacement != nullptr) {
1076           invoke_instruction->ReplaceWith(return_replacement);
1077         }
1078         invoke_instruction->GetBlock()->RemoveInstruction(invoke_instruction);
1079         // Because the inline cache data can be populated concurrently, we force the end of the
1080         // iteration. Otherwise, we could see a new receiver type.
1081         break;
1082       } else {
1083         CreateDiamondPatternForPolymorphicInline(compare, return_replacement, invoke_instruction);
1084       }
1085     }
1086   }
1087 
1088   if (!one_target_inlined) {
1089     LOG_FAIL_NO_STAT()
1090         << "Call to " << ArtMethod::PrettyMethod(resolved_method)
1091         << " from inline cache is not inlined because none"
1092         << " of its targets could be inlined";
1093     return false;
1094   }
1095 
1096   MaybeRecordStat(stats_, MethodCompilationStat::kInlinedPolymorphicCall);
1097 
1098   // Run type propagation to get the guards typed.
1099   ReferenceTypePropagation rtp_fixup(graph_,
1100                                      outer_compilation_unit_.GetClassLoader(),
1101                                      outer_compilation_unit_.GetDexCache(),
1102                                      /* is_first_run= */ false);
1103   rtp_fixup.Run();
1104   return true;
1105 }
1106 
CreateDiamondPatternForPolymorphicInline(HInstruction * compare,HInstruction * return_replacement,HInstruction * invoke_instruction)1107 void HInliner::CreateDiamondPatternForPolymorphicInline(HInstruction* compare,
1108                                                         HInstruction* return_replacement,
1109                                                         HInstruction* invoke_instruction) {
1110   uint32_t dex_pc = invoke_instruction->GetDexPc();
1111   HBasicBlock* cursor_block = compare->GetBlock();
1112   HBasicBlock* original_invoke_block = invoke_instruction->GetBlock();
1113   ArenaAllocator* allocator = graph_->GetAllocator();
1114 
1115   // Spit the block after the compare: `cursor_block` will now be the start of the diamond,
1116   // and the returned block is the start of the then branch (that could contain multiple blocks).
1117   HBasicBlock* then = cursor_block->SplitAfterForInlining(compare);
1118 
1119   // Split the block containing the invoke before and after the invoke. The returned block
1120   // of the split before will contain the invoke and will be the otherwise branch of
1121   // the diamond. The returned block of the split after will be the merge block
1122   // of the diamond.
1123   HBasicBlock* end_then = invoke_instruction->GetBlock();
1124   HBasicBlock* otherwise = end_then->SplitBeforeForInlining(invoke_instruction);
1125   HBasicBlock* merge = otherwise->SplitAfterForInlining(invoke_instruction);
1126 
1127   // If the methods we are inlining return a value, we create a phi in the merge block
1128   // that will have the `invoke_instruction and the `return_replacement` as inputs.
1129   if (return_replacement != nullptr) {
1130     HPhi* phi = new (allocator) HPhi(
1131         allocator, kNoRegNumber, 0, HPhi::ToPhiType(invoke_instruction->GetType()), dex_pc);
1132     merge->AddPhi(phi);
1133     invoke_instruction->ReplaceWith(phi);
1134     phi->AddInput(return_replacement);
1135     phi->AddInput(invoke_instruction);
1136   }
1137 
1138   // Add the control flow instructions.
1139   otherwise->AddInstruction(new (allocator) HGoto(dex_pc));
1140   end_then->AddInstruction(new (allocator) HGoto(dex_pc));
1141   cursor_block->AddInstruction(new (allocator) HIf(compare, dex_pc));
1142 
1143   // Add the newly created blocks to the graph.
1144   graph_->AddBlock(then);
1145   graph_->AddBlock(otherwise);
1146   graph_->AddBlock(merge);
1147 
1148   // Set up successor (and implictly predecessor) relations.
1149   cursor_block->AddSuccessor(otherwise);
1150   cursor_block->AddSuccessor(then);
1151   end_then->AddSuccessor(merge);
1152   otherwise->AddSuccessor(merge);
1153 
1154   // Set up dominance information.
1155   then->SetDominator(cursor_block);
1156   cursor_block->AddDominatedBlock(then);
1157   otherwise->SetDominator(cursor_block);
1158   cursor_block->AddDominatedBlock(otherwise);
1159   merge->SetDominator(cursor_block);
1160   cursor_block->AddDominatedBlock(merge);
1161 
1162   // Update the revert post order.
1163   size_t index = IndexOfElement(graph_->reverse_post_order_, cursor_block);
1164   MakeRoomFor(&graph_->reverse_post_order_, 1, index);
1165   graph_->reverse_post_order_[++index] = then;
1166   index = IndexOfElement(graph_->reverse_post_order_, end_then);
1167   MakeRoomFor(&graph_->reverse_post_order_, 2, index);
1168   graph_->reverse_post_order_[++index] = otherwise;
1169   graph_->reverse_post_order_[++index] = merge;
1170 
1171 
1172   graph_->UpdateLoopAndTryInformationOfNewBlock(
1173       then, original_invoke_block, /* replace_if_back_edge= */ false);
1174   graph_->UpdateLoopAndTryInformationOfNewBlock(
1175       otherwise, original_invoke_block, /* replace_if_back_edge= */ false);
1176 
1177   // In case the original invoke location was a back edge, we need to update
1178   // the loop to now have the merge block as a back edge.
1179   graph_->UpdateLoopAndTryInformationOfNewBlock(
1180       merge, original_invoke_block, /* replace_if_back_edge= */ true);
1181 }
1182 
TryInlinePolymorphicCallToSameTarget(HInvoke * invoke_instruction,ArtMethod * resolved_method,Handle<mirror::ObjectArray<mirror::Class>> classes)1183 bool HInliner::TryInlinePolymorphicCallToSameTarget(
1184     HInvoke* invoke_instruction,
1185     ArtMethod* resolved_method,
1186     Handle<mirror::ObjectArray<mirror::Class>> classes) {
1187   // This optimization only works under JIT for now.
1188   if (!codegen_->GetCompilerOptions().IsJitCompiler()) {
1189     return false;
1190   }
1191 
1192   ClassLinker* class_linker = caller_compilation_unit_.GetClassLinker();
1193   PointerSize pointer_size = class_linker->GetImagePointerSize();
1194 
1195   DCHECK(resolved_method != nullptr);
1196   ArtMethod* actual_method = nullptr;
1197   size_t method_index = invoke_instruction->IsInvokeVirtual()
1198       ? invoke_instruction->AsInvokeVirtual()->GetVTableIndex()
1199       : invoke_instruction->AsInvokeInterface()->GetImtIndex();
1200 
1201   // Check whether we are actually calling the same method among
1202   // the different types seen.
1203   for (size_t i = 0; i < InlineCache::kIndividualCacheSize; ++i) {
1204     if (classes->Get(i) == nullptr) {
1205       break;
1206     }
1207     ArtMethod* new_method = nullptr;
1208     if (invoke_instruction->IsInvokeInterface()) {
1209       new_method = classes->Get(i)->GetImt(pointer_size)->Get(
1210           method_index, pointer_size);
1211       if (new_method->IsRuntimeMethod()) {
1212         // Bail out as soon as we see a conflict trampoline in one of the target's
1213         // interface table.
1214         return false;
1215       }
1216     } else {
1217       DCHECK(invoke_instruction->IsInvokeVirtual());
1218       new_method = classes->Get(i)->GetEmbeddedVTableEntry(method_index, pointer_size);
1219     }
1220     DCHECK(new_method != nullptr);
1221     if (actual_method == nullptr) {
1222       actual_method = new_method;
1223     } else if (actual_method != new_method) {
1224       // Different methods, bailout.
1225       return false;
1226     }
1227   }
1228 
1229   HInstruction* receiver = invoke_instruction->InputAt(0);
1230   HInstruction* cursor = invoke_instruction->GetPrevious();
1231   HBasicBlock* bb_cursor = invoke_instruction->GetBlock();
1232 
1233   HInstruction* return_replacement = nullptr;
1234   if (!TryBuildAndInline(invoke_instruction,
1235                          actual_method,
1236                          ReferenceTypeInfo::CreateInvalid(),
1237                          &return_replacement)) {
1238     return false;
1239   }
1240 
1241   // We successfully inlined, now add a guard.
1242   HInstanceFieldGet* receiver_class = BuildGetReceiverClass(
1243       class_linker, receiver, invoke_instruction->GetDexPc());
1244 
1245   DataType::Type type = Is64BitInstructionSet(graph_->GetInstructionSet())
1246       ? DataType::Type::kInt64
1247       : DataType::Type::kInt32;
1248   HClassTableGet* class_table_get = new (graph_->GetAllocator()) HClassTableGet(
1249       receiver_class,
1250       type,
1251       invoke_instruction->IsInvokeVirtual() ? HClassTableGet::TableKind::kVTable
1252                                             : HClassTableGet::TableKind::kIMTable,
1253       method_index,
1254       invoke_instruction->GetDexPc());
1255 
1256   HConstant* constant;
1257   if (type == DataType::Type::kInt64) {
1258     constant = graph_->GetLongConstant(
1259         reinterpret_cast<intptr_t>(actual_method), invoke_instruction->GetDexPc());
1260   } else {
1261     constant = graph_->GetIntConstant(
1262         reinterpret_cast<intptr_t>(actual_method), invoke_instruction->GetDexPc());
1263   }
1264 
1265   HNotEqual* compare = new (graph_->GetAllocator()) HNotEqual(class_table_get, constant);
1266   if (cursor != nullptr) {
1267     bb_cursor->InsertInstructionAfter(receiver_class, cursor);
1268   } else {
1269     bb_cursor->InsertInstructionBefore(receiver_class, bb_cursor->GetFirstInstruction());
1270   }
1271   bb_cursor->InsertInstructionAfter(class_table_get, receiver_class);
1272   bb_cursor->InsertInstructionAfter(compare, class_table_get);
1273 
1274   if (outermost_graph_->IsCompilingOsr()) {
1275     CreateDiamondPatternForPolymorphicInline(compare, return_replacement, invoke_instruction);
1276   } else {
1277     HDeoptimize* deoptimize = new (graph_->GetAllocator()) HDeoptimize(
1278         graph_->GetAllocator(),
1279         compare,
1280         receiver,
1281         DeoptimizationKind::kJitSameTarget,
1282         invoke_instruction->GetDexPc());
1283     bb_cursor->InsertInstructionAfter(deoptimize, compare);
1284     deoptimize->CopyEnvironmentFrom(invoke_instruction->GetEnvironment());
1285     if (return_replacement != nullptr) {
1286       invoke_instruction->ReplaceWith(return_replacement);
1287     }
1288     receiver->ReplaceUsesDominatedBy(deoptimize, deoptimize);
1289     invoke_instruction->GetBlock()->RemoveInstruction(invoke_instruction);
1290     deoptimize->SetReferenceTypeInfo(receiver->GetReferenceTypeInfo());
1291   }
1292 
1293   // Run type propagation to get the guard typed.
1294   ReferenceTypePropagation rtp_fixup(graph_,
1295                                      outer_compilation_unit_.GetClassLoader(),
1296                                      outer_compilation_unit_.GetDexCache(),
1297                                      /* is_first_run= */ false);
1298   rtp_fixup.Run();
1299 
1300   MaybeRecordStat(stats_, MethodCompilationStat::kInlinedPolymorphicCall);
1301 
1302   LOG_SUCCESS() << "Inlined same polymorphic target " << actual_method->PrettyMethod();
1303   return true;
1304 }
1305 
TryInlineAndReplace(HInvoke * invoke_instruction,ArtMethod * method,ReferenceTypeInfo receiver_type,bool do_rtp,bool cha_devirtualize)1306 bool HInliner::TryInlineAndReplace(HInvoke* invoke_instruction,
1307                                    ArtMethod* method,
1308                                    ReferenceTypeInfo receiver_type,
1309                                    bool do_rtp,
1310                                    bool cha_devirtualize) {
1311   DCHECK(!invoke_instruction->IsIntrinsic());
1312   HInstruction* return_replacement = nullptr;
1313   uint32_t dex_pc = invoke_instruction->GetDexPc();
1314   HInstruction* cursor = invoke_instruction->GetPrevious();
1315   HBasicBlock* bb_cursor = invoke_instruction->GetBlock();
1316   bool should_remove_invoke_instruction = false;
1317 
1318   // If invoke_instruction is devirtualized to a different method, give intrinsics
1319   // another chance before we try to inline it.
1320   if (invoke_instruction->GetResolvedMethod() != method && method->IsIntrinsic()) {
1321     MaybeRecordStat(stats_, MethodCompilationStat::kIntrinsicRecognized);
1322     if (invoke_instruction->IsInvokeInterface()) {
1323       // We don't intrinsify an invoke-interface directly.
1324       // Replace the invoke-interface with an invoke-virtual.
1325       HInvokeVirtual* new_invoke = new (graph_->GetAllocator()) HInvokeVirtual(
1326           graph_->GetAllocator(),
1327           invoke_instruction->GetNumberOfArguments(),
1328           invoke_instruction->GetType(),
1329           invoke_instruction->GetDexPc(),
1330           invoke_instruction->GetDexMethodIndex(),  // Use interface method's dex method index.
1331           method,
1332           method->GetMethodIndex());
1333       DCHECK_NE(new_invoke->GetIntrinsic(), Intrinsics::kNone);
1334       HInputsRef inputs = invoke_instruction->GetInputs();
1335       for (size_t index = 0; index != inputs.size(); ++index) {
1336         new_invoke->SetArgumentAt(index, inputs[index]);
1337       }
1338       invoke_instruction->GetBlock()->InsertInstructionBefore(new_invoke, invoke_instruction);
1339       new_invoke->CopyEnvironmentFrom(invoke_instruction->GetEnvironment());
1340       if (invoke_instruction->GetType() == DataType::Type::kReference) {
1341         new_invoke->SetReferenceTypeInfo(invoke_instruction->GetReferenceTypeInfo());
1342       }
1343       return_replacement = new_invoke;
1344       // invoke_instruction is replaced with new_invoke.
1345       should_remove_invoke_instruction = true;
1346     } else {
1347       invoke_instruction->SetResolvedMethod(method);
1348     }
1349   } else if (!TryBuildAndInline(invoke_instruction, method, receiver_type, &return_replacement)) {
1350     if (invoke_instruction->IsInvokeInterface()) {
1351       DCHECK(!method->IsProxyMethod());
1352       // Turn an invoke-interface into an invoke-virtual. An invoke-virtual is always
1353       // better than an invoke-interface because:
1354       // 1) In the best case, the interface call has one more indirection (to fetch the IMT).
1355       // 2) We will not go to the conflict trampoline with an invoke-virtual.
1356       // TODO: Consider sharpening once it is not dependent on the compiler driver.
1357 
1358       if (method->IsDefault() && !method->IsCopied()) {
1359         // Changing to invoke-virtual cannot be done on an original default method
1360         // since it's not in any vtable. Devirtualization by exact type/inline-cache
1361         // always uses a method in the iftable which is never an original default
1362         // method.
1363         // On the other hand, inlining an original default method by CHA is fine.
1364         DCHECK(cha_devirtualize);
1365         return false;
1366       }
1367 
1368       const DexFile& caller_dex_file = *caller_compilation_unit_.GetDexFile();
1369       uint32_t dex_method_index = FindMethodIndexIn(
1370           method, caller_dex_file, invoke_instruction->GetDexMethodIndex());
1371       if (dex_method_index == dex::kDexNoIndex) {
1372         return false;
1373       }
1374       HInvokeVirtual* new_invoke = new (graph_->GetAllocator()) HInvokeVirtual(
1375           graph_->GetAllocator(),
1376           invoke_instruction->GetNumberOfArguments(),
1377           invoke_instruction->GetType(),
1378           invoke_instruction->GetDexPc(),
1379           dex_method_index,
1380           method,
1381           method->GetMethodIndex());
1382       HInputsRef inputs = invoke_instruction->GetInputs();
1383       for (size_t index = 0; index != inputs.size(); ++index) {
1384         new_invoke->SetArgumentAt(index, inputs[index]);
1385       }
1386       invoke_instruction->GetBlock()->InsertInstructionBefore(new_invoke, invoke_instruction);
1387       new_invoke->CopyEnvironmentFrom(invoke_instruction->GetEnvironment());
1388       if (invoke_instruction->GetType() == DataType::Type::kReference) {
1389         new_invoke->SetReferenceTypeInfo(invoke_instruction->GetReferenceTypeInfo());
1390       }
1391       return_replacement = new_invoke;
1392       // invoke_instruction is replaced with new_invoke.
1393       should_remove_invoke_instruction = true;
1394     } else {
1395       // TODO: Consider sharpening an invoke virtual once it is not dependent on the
1396       // compiler driver.
1397       return false;
1398     }
1399   } else {
1400     // invoke_instruction is inlined.
1401     should_remove_invoke_instruction = true;
1402   }
1403 
1404   if (cha_devirtualize) {
1405     AddCHAGuard(invoke_instruction, dex_pc, cursor, bb_cursor);
1406   }
1407   if (return_replacement != nullptr) {
1408     invoke_instruction->ReplaceWith(return_replacement);
1409   }
1410   if (should_remove_invoke_instruction) {
1411     invoke_instruction->GetBlock()->RemoveInstruction(invoke_instruction);
1412   }
1413   FixUpReturnReferenceType(method, return_replacement);
1414   if (do_rtp && ReturnTypeMoreSpecific(invoke_instruction, return_replacement)) {
1415     // Actual return value has a more specific type than the method's declared
1416     // return type. Run RTP again on the outer graph to propagate it.
1417     ReferenceTypePropagation(graph_,
1418                              outer_compilation_unit_.GetClassLoader(),
1419                              outer_compilation_unit_.GetDexCache(),
1420                              /* is_first_run= */ false).Run();
1421   }
1422   return true;
1423 }
1424 
CountRecursiveCallsOf(ArtMethod * method) const1425 size_t HInliner::CountRecursiveCallsOf(ArtMethod* method) const {
1426   const HInliner* current = this;
1427   size_t count = 0;
1428   do {
1429     if (current->graph_->GetArtMethod() == method) {
1430       ++count;
1431     }
1432     current = current->parent_;
1433   } while (current != nullptr);
1434   return count;
1435 }
1436 
MayInline(const CompilerOptions & compiler_options,const DexFile & inlined_from,const DexFile & inlined_into)1437 static inline bool MayInline(const CompilerOptions& compiler_options,
1438                              const DexFile& inlined_from,
1439                              const DexFile& inlined_into) {
1440   // We're not allowed to inline across dex files if we're the no-inline-from dex file.
1441   if (!IsSameDexFile(inlined_from, inlined_into) &&
1442       ContainsElement(compiler_options.GetNoInlineFromDexFile(), &inlined_from)) {
1443     return false;
1444   }
1445 
1446   return true;
1447 }
1448 
1449 // Returns whether inlining is allowed based on ART semantics.
IsInliningAllowed(ArtMethod * method,const CodeItemDataAccessor & accessor) const1450 bool HInliner::IsInliningAllowed(ArtMethod* method, const CodeItemDataAccessor& accessor) const {
1451   if (!accessor.HasCodeItem()) {
1452     LOG_FAIL_NO_STAT()
1453         << "Method " << method->PrettyMethod() << " is not inlined because it is native";
1454     return false;
1455   }
1456 
1457   if (!method->IsCompilable()) {
1458     LOG_FAIL(stats_, MethodCompilationStat::kNotInlinedNotVerified)
1459         << "Method " << method->PrettyMethod()
1460         << " has soft failures un-handled by the compiler, so it cannot be inlined";
1461     return false;
1462   }
1463 
1464   if (IsMethodUnverified(codegen_->GetCompilerOptions(), method)) {
1465     LOG_FAIL(stats_, MethodCompilationStat::kNotInlinedNotVerified)
1466         << "Method " << method->PrettyMethod()
1467         << " couldn't be verified, so it cannot be inlined";
1468     return false;
1469   }
1470 
1471   return true;
1472 }
1473 
1474 // Returns whether ART supports inlining this method.
1475 //
1476 // Some methods are not supported because they have features for which inlining
1477 // is not implemented. For example, we do not currently support inlining throw
1478 // instructions into a try block.
IsInliningSupported(const HInvoke * invoke_instruction,ArtMethod * method,const CodeItemDataAccessor & accessor) const1479 bool HInliner::IsInliningSupported(const HInvoke* invoke_instruction,
1480                                    ArtMethod* method,
1481                                    const CodeItemDataAccessor& accessor) const {
1482   if (method->IsProxyMethod()) {
1483     LOG_FAIL(stats_, MethodCompilationStat::kNotInlinedProxy)
1484         << "Method " << method->PrettyMethod()
1485         << " is not inlined because of unimplemented inline support for proxy methods.";
1486     return false;
1487   }
1488 
1489   if (accessor.TriesSize() != 0) {
1490     LOG_FAIL(stats_, MethodCompilationStat::kNotInlinedTryCatch)
1491         << "Method " << method->PrettyMethod() << " is not inlined because of try block";
1492     return false;
1493   }
1494 
1495   if (invoke_instruction->IsInvokeStaticOrDirect() &&
1496       invoke_instruction->AsInvokeStaticOrDirect()->IsStaticWithImplicitClinitCheck()) {
1497     // Case of a static method that cannot be inlined because it implicitly
1498     // requires an initialization check of its declaring class.
1499     LOG_FAIL(stats_, MethodCompilationStat::kNotInlinedDexCache)
1500         << "Method " << method->PrettyMethod()
1501         << " is not inlined because it is static and requires a clinit"
1502         << " check that cannot be emitted due to Dex cache limitations";
1503     return false;
1504   }
1505 
1506   return true;
1507 }
1508 
1509 // Returns whether our resource limits allow inlining this method.
IsInliningBudgetAvailable(ArtMethod * method,const CodeItemDataAccessor & accessor) const1510 bool HInliner::IsInliningBudgetAvailable(ArtMethod* method,
1511                                          const CodeItemDataAccessor& accessor) const {
1512   if (CountRecursiveCallsOf(method) > kMaximumNumberOfRecursiveCalls) {
1513     LOG_FAIL(stats_, MethodCompilationStat::kNotInlinedRecursiveBudget)
1514         << "Method "
1515         << method->PrettyMethod()
1516         << " is not inlined because it has reached its recursive call budget.";
1517     return false;
1518   }
1519 
1520   size_t inline_max_code_units = codegen_->GetCompilerOptions().GetInlineMaxCodeUnits();
1521   if (accessor.InsnsSizeInCodeUnits() > inline_max_code_units) {
1522     LOG_FAIL(stats_, MethodCompilationStat::kNotInlinedCodeItem)
1523         << "Method " << method->PrettyMethod()
1524         << " is not inlined because its code item is too big: "
1525         << accessor.InsnsSizeInCodeUnits()
1526         << " > "
1527         << inline_max_code_units;
1528     return false;
1529   }
1530 
1531   return true;
1532 }
1533 
TryBuildAndInline(HInvoke * invoke_instruction,ArtMethod * method,ReferenceTypeInfo receiver_type,HInstruction ** return_replacement)1534 bool HInliner::TryBuildAndInline(HInvoke* invoke_instruction,
1535                                  ArtMethod* method,
1536                                  ReferenceTypeInfo receiver_type,
1537                                  HInstruction** return_replacement) {
1538   // Check whether we're allowed to inline. The outermost compilation unit is the relevant
1539   // dex file here (though the transitivity of an inline chain would allow checking the caller).
1540   if (!MayInline(codegen_->GetCompilerOptions(),
1541                  *method->GetDexFile(),
1542                  *outer_compilation_unit_.GetDexFile())) {
1543     if (TryPatternSubstitution(invoke_instruction, method, return_replacement)) {
1544       LOG_SUCCESS() << "Successfully replaced pattern of invoke "
1545                     << method->PrettyMethod();
1546       MaybeRecordStat(stats_, MethodCompilationStat::kReplacedInvokeWithSimplePattern);
1547       return true;
1548     }
1549     LOG_FAIL(stats_, MethodCompilationStat::kNotInlinedWont)
1550         << "Won't inline " << method->PrettyMethod() << " in "
1551         << outer_compilation_unit_.GetDexFile()->GetLocation() << " ("
1552         << caller_compilation_unit_.GetDexFile()->GetLocation() << ") from "
1553         << method->GetDexFile()->GetLocation();
1554     return false;
1555   }
1556 
1557   CodeItemDataAccessor accessor(method->DexInstructionData());
1558 
1559   if (!IsInliningAllowed(method, accessor)) {
1560     return false;
1561   }
1562 
1563   if (!IsInliningSupported(invoke_instruction, method, accessor)) {
1564     return false;
1565   }
1566 
1567   if (!IsInliningBudgetAvailable(method, accessor)) {
1568     return false;
1569   }
1570 
1571   if (!TryBuildAndInlineHelper(
1572           invoke_instruction, method, receiver_type, return_replacement)) {
1573     return false;
1574   }
1575 
1576   LOG_SUCCESS() << method->PrettyMethod();
1577   MaybeRecordStat(stats_, MethodCompilationStat::kInlinedInvoke);
1578   return true;
1579 }
1580 
GetInvokeInputForArgVRegIndex(HInvoke * invoke_instruction,size_t arg_vreg_index)1581 static HInstruction* GetInvokeInputForArgVRegIndex(HInvoke* invoke_instruction,
1582                                                    size_t arg_vreg_index)
1583     REQUIRES_SHARED(Locks::mutator_lock_) {
1584   size_t input_index = 0;
1585   for (size_t i = 0; i < arg_vreg_index; ++i, ++input_index) {
1586     DCHECK_LT(input_index, invoke_instruction->GetNumberOfArguments());
1587     if (DataType::Is64BitType(invoke_instruction->InputAt(input_index)->GetType())) {
1588       ++i;
1589       DCHECK_NE(i, arg_vreg_index);
1590     }
1591   }
1592   DCHECK_LT(input_index, invoke_instruction->GetNumberOfArguments());
1593   return invoke_instruction->InputAt(input_index);
1594 }
1595 
1596 // Try to recognize known simple patterns and replace invoke call with appropriate instructions.
TryPatternSubstitution(HInvoke * invoke_instruction,ArtMethod * resolved_method,HInstruction ** return_replacement)1597 bool HInliner::TryPatternSubstitution(HInvoke* invoke_instruction,
1598                                       ArtMethod* resolved_method,
1599                                       HInstruction** return_replacement) {
1600   InlineMethod inline_method;
1601   if (!InlineMethodAnalyser::AnalyseMethodCode(resolved_method, &inline_method)) {
1602     return false;
1603   }
1604 
1605   switch (inline_method.opcode) {
1606     case kInlineOpNop:
1607       DCHECK_EQ(invoke_instruction->GetType(), DataType::Type::kVoid);
1608       *return_replacement = nullptr;
1609       break;
1610     case kInlineOpReturnArg:
1611       *return_replacement = GetInvokeInputForArgVRegIndex(invoke_instruction,
1612                                                           inline_method.d.return_data.arg);
1613       break;
1614     case kInlineOpNonWideConst:
1615       if (resolved_method->GetShorty()[0] == 'L') {
1616         DCHECK_EQ(inline_method.d.data, 0u);
1617         *return_replacement = graph_->GetNullConstant();
1618       } else {
1619         *return_replacement = graph_->GetIntConstant(static_cast<int32_t>(inline_method.d.data));
1620       }
1621       break;
1622     case kInlineOpIGet: {
1623       const InlineIGetIPutData& data = inline_method.d.ifield_data;
1624       if (data.method_is_static || data.object_arg != 0u) {
1625         // TODO: Needs null check.
1626         return false;
1627       }
1628       HInstruction* obj = GetInvokeInputForArgVRegIndex(invoke_instruction, data.object_arg);
1629       HInstanceFieldGet* iget = CreateInstanceFieldGet(data.field_idx, resolved_method, obj);
1630       DCHECK_EQ(iget->GetFieldOffset().Uint32Value(), data.field_offset);
1631       DCHECK_EQ(iget->IsVolatile() ? 1u : 0u, data.is_volatile);
1632       invoke_instruction->GetBlock()->InsertInstructionBefore(iget, invoke_instruction);
1633       *return_replacement = iget;
1634       break;
1635     }
1636     case kInlineOpIPut: {
1637       const InlineIGetIPutData& data = inline_method.d.ifield_data;
1638       if (data.method_is_static || data.object_arg != 0u) {
1639         // TODO: Needs null check.
1640         return false;
1641       }
1642       HInstruction* obj = GetInvokeInputForArgVRegIndex(invoke_instruction, data.object_arg);
1643       HInstruction* value = GetInvokeInputForArgVRegIndex(invoke_instruction, data.src_arg);
1644       HInstanceFieldSet* iput = CreateInstanceFieldSet(data.field_idx, resolved_method, obj, value);
1645       DCHECK_EQ(iput->GetFieldOffset().Uint32Value(), data.field_offset);
1646       DCHECK_EQ(iput->IsVolatile() ? 1u : 0u, data.is_volatile);
1647       invoke_instruction->GetBlock()->InsertInstructionBefore(iput, invoke_instruction);
1648       if (data.return_arg_plus1 != 0u) {
1649         size_t return_arg = data.return_arg_plus1 - 1u;
1650         *return_replacement = GetInvokeInputForArgVRegIndex(invoke_instruction, return_arg);
1651       }
1652       break;
1653     }
1654     case kInlineOpConstructor: {
1655       const InlineConstructorData& data = inline_method.d.constructor_data;
1656       // Get the indexes to arrays for easier processing.
1657       uint16_t iput_field_indexes[] = {
1658           data.iput0_field_index, data.iput1_field_index, data.iput2_field_index
1659       };
1660       uint16_t iput_args[] = { data.iput0_arg, data.iput1_arg, data.iput2_arg };
1661       static_assert(arraysize(iput_args) == arraysize(iput_field_indexes), "Size mismatch");
1662       // Count valid field indexes.
1663       size_t number_of_iputs = 0u;
1664       while (number_of_iputs != arraysize(iput_field_indexes) &&
1665           iput_field_indexes[number_of_iputs] != DexFile::kDexNoIndex16) {
1666         // Check that there are no duplicate valid field indexes.
1667         DCHECK_EQ(0, std::count(iput_field_indexes + number_of_iputs + 1,
1668                                 iput_field_indexes + arraysize(iput_field_indexes),
1669                                 iput_field_indexes[number_of_iputs]));
1670         ++number_of_iputs;
1671       }
1672       // Check that there are no valid field indexes in the rest of the array.
1673       DCHECK_EQ(0, std::count_if(iput_field_indexes + number_of_iputs,
1674                                  iput_field_indexes + arraysize(iput_field_indexes),
1675                                  [](uint16_t index) { return index != DexFile::kDexNoIndex16; }));
1676 
1677       // Create HInstanceFieldSet for each IPUT that stores non-zero data.
1678       HInstruction* obj = GetInvokeInputForArgVRegIndex(invoke_instruction,
1679                                                         /* arg_vreg_index= */ 0u);
1680       bool needs_constructor_barrier = false;
1681       for (size_t i = 0; i != number_of_iputs; ++i) {
1682         HInstruction* value = GetInvokeInputForArgVRegIndex(invoke_instruction, iput_args[i]);
1683         if (!value->IsConstant() || !value->AsConstant()->IsZeroBitPattern()) {
1684           uint16_t field_index = iput_field_indexes[i];
1685           bool is_final;
1686           HInstanceFieldSet* iput =
1687               CreateInstanceFieldSet(field_index, resolved_method, obj, value, &is_final);
1688           invoke_instruction->GetBlock()->InsertInstructionBefore(iput, invoke_instruction);
1689 
1690           // Check whether the field is final. If it is, we need to add a barrier.
1691           if (is_final) {
1692             needs_constructor_barrier = true;
1693           }
1694         }
1695       }
1696       if (needs_constructor_barrier) {
1697         // See DexCompilationUnit::RequiresConstructorBarrier for more details.
1698         DCHECK(obj != nullptr) << "only non-static methods can have a constructor fence";
1699 
1700         HConstructorFence* constructor_fence =
1701             new (graph_->GetAllocator()) HConstructorFence(obj, kNoDexPc, graph_->GetAllocator());
1702         invoke_instruction->GetBlock()->InsertInstructionBefore(constructor_fence,
1703                                                                 invoke_instruction);
1704       }
1705       *return_replacement = nullptr;
1706       break;
1707     }
1708     default:
1709       LOG(FATAL) << "UNREACHABLE";
1710       UNREACHABLE();
1711   }
1712   return true;
1713 }
1714 
CreateInstanceFieldGet(uint32_t field_index,ArtMethod * referrer,HInstruction * obj)1715 HInstanceFieldGet* HInliner::CreateInstanceFieldGet(uint32_t field_index,
1716                                                     ArtMethod* referrer,
1717                                                     HInstruction* obj)
1718     REQUIRES_SHARED(Locks::mutator_lock_) {
1719   ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
1720   ArtField* resolved_field =
1721       class_linker->LookupResolvedField(field_index, referrer, /* is_static= */ false);
1722   DCHECK(resolved_field != nullptr);
1723   HInstanceFieldGet* iget = new (graph_->GetAllocator()) HInstanceFieldGet(
1724       obj,
1725       resolved_field,
1726       DataType::FromShorty(resolved_field->GetTypeDescriptor()[0]),
1727       resolved_field->GetOffset(),
1728       resolved_field->IsVolatile(),
1729       field_index,
1730       resolved_field->GetDeclaringClass()->GetDexClassDefIndex(),
1731       *referrer->GetDexFile(),
1732       // Read barrier generates a runtime call in slow path and we need a valid
1733       // dex pc for the associated stack map. 0 is bogus but valid. Bug: 26854537.
1734       /* dex_pc= */ 0);
1735   if (iget->GetType() == DataType::Type::kReference) {
1736     // Use the same dex_cache that we used for field lookup as the hint_dex_cache.
1737     Handle<mirror::DexCache> dex_cache =
1738         graph_->GetHandleCache()->NewHandle(referrer->GetDexCache());
1739     ReferenceTypePropagation rtp(graph_,
1740                                  outer_compilation_unit_.GetClassLoader(),
1741                                  dex_cache,
1742                                  /* is_first_run= */ false);
1743     rtp.Visit(iget);
1744   }
1745   return iget;
1746 }
1747 
CreateInstanceFieldSet(uint32_t field_index,ArtMethod * referrer,HInstruction * obj,HInstruction * value,bool * is_final)1748 HInstanceFieldSet* HInliner::CreateInstanceFieldSet(uint32_t field_index,
1749                                                     ArtMethod* referrer,
1750                                                     HInstruction* obj,
1751                                                     HInstruction* value,
1752                                                     bool* is_final)
1753     REQUIRES_SHARED(Locks::mutator_lock_) {
1754   ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
1755   ArtField* resolved_field =
1756       class_linker->LookupResolvedField(field_index, referrer, /* is_static= */ false);
1757   DCHECK(resolved_field != nullptr);
1758   if (is_final != nullptr) {
1759     // This information is needed only for constructors.
1760     DCHECK(referrer->IsConstructor());
1761     *is_final = resolved_field->IsFinal();
1762   }
1763   HInstanceFieldSet* iput = new (graph_->GetAllocator()) HInstanceFieldSet(
1764       obj,
1765       value,
1766       resolved_field,
1767       DataType::FromShorty(resolved_field->GetTypeDescriptor()[0]),
1768       resolved_field->GetOffset(),
1769       resolved_field->IsVolatile(),
1770       field_index,
1771       resolved_field->GetDeclaringClass()->GetDexClassDefIndex(),
1772       *referrer->GetDexFile(),
1773       // Read barrier generates a runtime call in slow path and we need a valid
1774       // dex pc for the associated stack map. 0 is bogus but valid. Bug: 26854537.
1775       /* dex_pc= */ 0);
1776   return iput;
1777 }
1778 
1779 template <typename T>
NewHandleIfDifferent(ObjPtr<T> object,Handle<T> hint,HGraph * graph)1780 static inline Handle<T> NewHandleIfDifferent(ObjPtr<T> object, Handle<T> hint, HGraph* graph)
1781     REQUIRES_SHARED(Locks::mutator_lock_) {
1782   return (object != hint.Get()) ? graph->GetHandleCache()->NewHandle(object) : hint;
1783 }
1784 
CanEncodeInlinedMethodInStackMap(const DexFile & caller_dex_file,ArtMethod * callee)1785 static bool CanEncodeInlinedMethodInStackMap(const DexFile& caller_dex_file, ArtMethod* callee)
1786     REQUIRES_SHARED(Locks::mutator_lock_) {
1787   if (!Runtime::Current()->IsAotCompiler()) {
1788     // JIT can always encode methods in stack maps.
1789     return true;
1790   }
1791   if (IsSameDexFile(caller_dex_file, *callee->GetDexFile())) {
1792     return true;
1793   }
1794   // TODO(ngeoffray): Support more AOT cases for inlining:
1795   // - methods in multidex
1796   // - methods in boot image for on-device non-PIC compilation.
1797   return false;
1798 }
1799 
1800   // Substitutes parameters in the callee graph with their values from the caller.
SubstituteArguments(HGraph * callee_graph,HInvoke * invoke_instruction,ReferenceTypeInfo receiver_type,const DexCompilationUnit & dex_compilation_unit)1801 void HInliner::SubstituteArguments(HGraph* callee_graph,
1802                                    HInvoke* invoke_instruction,
1803                                    ReferenceTypeInfo receiver_type,
1804                                    const DexCompilationUnit& dex_compilation_unit) {
1805   ArtMethod* const resolved_method = callee_graph->GetArtMethod();
1806   size_t parameter_index = 0;
1807   bool run_rtp = false;
1808   for (HInstructionIterator instructions(callee_graph->GetEntryBlock()->GetInstructions());
1809        !instructions.Done();
1810        instructions.Advance()) {
1811     HInstruction* current = instructions.Current();
1812     if (current->IsParameterValue()) {
1813       HInstruction* argument = invoke_instruction->InputAt(parameter_index);
1814       if (argument->IsNullConstant()) {
1815         current->ReplaceWith(callee_graph->GetNullConstant());
1816       } else if (argument->IsIntConstant()) {
1817         current->ReplaceWith(callee_graph->GetIntConstant(argument->AsIntConstant()->GetValue()));
1818       } else if (argument->IsLongConstant()) {
1819         current->ReplaceWith(callee_graph->GetLongConstant(argument->AsLongConstant()->GetValue()));
1820       } else if (argument->IsFloatConstant()) {
1821         current->ReplaceWith(
1822             callee_graph->GetFloatConstant(argument->AsFloatConstant()->GetValue()));
1823       } else if (argument->IsDoubleConstant()) {
1824         current->ReplaceWith(
1825             callee_graph->GetDoubleConstant(argument->AsDoubleConstant()->GetValue()));
1826       } else if (argument->GetType() == DataType::Type::kReference) {
1827         if (!resolved_method->IsStatic() && parameter_index == 0 && receiver_type.IsValid()) {
1828           run_rtp = true;
1829           current->SetReferenceTypeInfo(receiver_type);
1830         } else {
1831           current->SetReferenceTypeInfo(argument->GetReferenceTypeInfo());
1832         }
1833         current->AsParameterValue()->SetCanBeNull(argument->CanBeNull());
1834       }
1835       ++parameter_index;
1836     }
1837   }
1838 
1839   // We have replaced formal arguments with actual arguments. If actual types
1840   // are more specific than the declared ones, run RTP again on the inner graph.
1841   if (run_rtp || ArgumentTypesMoreSpecific(invoke_instruction, resolved_method)) {
1842     ReferenceTypePropagation(callee_graph,
1843                              outer_compilation_unit_.GetClassLoader(),
1844                              dex_compilation_unit.GetDexCache(),
1845                              /* is_first_run= */ false).Run();
1846   }
1847 }
1848 
1849 // Returns whether we can inline the callee_graph into the target_block.
1850 //
1851 // This performs a combination of semantics checks, compiler support checks, and
1852 // resource limit checks.
1853 //
1854 // If this function returns true, it will also set out_number_of_instructions to
1855 // the number of instructions in the inlined body.
CanInlineBody(const HGraph * callee_graph,const HBasicBlock * target_block,size_t * out_number_of_instructions) const1856 bool HInliner::CanInlineBody(const HGraph* callee_graph,
1857                              const HBasicBlock* target_block,
1858                              size_t* out_number_of_instructions) const {
1859   const DexFile& callee_dex_file = callee_graph->GetDexFile();
1860   ArtMethod* const resolved_method = callee_graph->GetArtMethod();
1861   const uint32_t method_index = resolved_method->GetMethodIndex();
1862   const bool same_dex_file =
1863       IsSameDexFile(*outer_compilation_unit_.GetDexFile(), *resolved_method->GetDexFile());
1864 
1865   HBasicBlock* exit_block = callee_graph->GetExitBlock();
1866   if (exit_block == nullptr) {
1867     LOG_FAIL(stats_, MethodCompilationStat::kNotInlinedInfiniteLoop)
1868         << "Method " << callee_dex_file.PrettyMethod(method_index)
1869         << " could not be inlined because it has an infinite loop";
1870     return false;
1871   }
1872 
1873   bool has_one_return = false;
1874   for (HBasicBlock* predecessor : exit_block->GetPredecessors()) {
1875     if (predecessor->GetLastInstruction()->IsThrow()) {
1876       if (target_block->IsTryBlock()) {
1877         // TODO(ngeoffray): Support adding HTryBoundary in Hgraph::InlineInto.
1878         LOG_FAIL(stats_, MethodCompilationStat::kNotInlinedTryCatch)
1879             << "Method " << callee_dex_file.PrettyMethod(method_index)
1880             << " could not be inlined because one branch always throws and"
1881             << " caller is in a try/catch block";
1882         return false;
1883       } else if (graph_->GetExitBlock() == nullptr) {
1884         // TODO(ngeoffray): Support adding HExit in the caller graph.
1885         LOG_FAIL(stats_, MethodCompilationStat::kNotInlinedInfiniteLoop)
1886             << "Method " << callee_dex_file.PrettyMethod(method_index)
1887             << " could not be inlined because one branch always throws and"
1888             << " caller does not have an exit block";
1889         return false;
1890       } else if (graph_->HasIrreducibleLoops()) {
1891         // TODO(ngeoffray): Support re-computing loop information to graphs with
1892         // irreducible loops?
1893         VLOG(compiler) << "Method " << callee_dex_file.PrettyMethod(method_index)
1894                        << " could not be inlined because one branch always throws and"
1895                        << " caller has irreducible loops";
1896         return false;
1897       }
1898     } else {
1899       has_one_return = true;
1900     }
1901   }
1902 
1903   if (!has_one_return) {
1904     LOG_FAIL(stats_, MethodCompilationStat::kNotInlinedAlwaysThrows)
1905         << "Method " << callee_dex_file.PrettyMethod(method_index)
1906         << " could not be inlined because it always throws";
1907     return false;
1908   }
1909 
1910   size_t number_of_instructions = 0;
1911   // Skip the entry block, it does not contain instructions that prevent inlining.
1912   for (HBasicBlock* block : callee_graph->GetReversePostOrderSkipEntryBlock()) {
1913     if (block->IsLoopHeader()) {
1914       if (block->GetLoopInformation()->IsIrreducible()) {
1915         // Don't inline methods with irreducible loops, they could prevent some
1916         // optimizations to run.
1917         LOG_FAIL(stats_, MethodCompilationStat::kNotInlinedIrreducibleLoop)
1918             << "Method " << callee_dex_file.PrettyMethod(method_index)
1919             << " could not be inlined because it contains an irreducible loop";
1920         return false;
1921       }
1922       if (!block->GetLoopInformation()->HasExitEdge()) {
1923         // Don't inline methods with loops without exit, since they cause the
1924         // loop information to be computed incorrectly when updating after
1925         // inlining.
1926         LOG_FAIL(stats_, MethodCompilationStat::kNotInlinedLoopWithoutExit)
1927             << "Method " << callee_dex_file.PrettyMethod(method_index)
1928             << " could not be inlined because it contains a loop with no exit";
1929         return false;
1930       }
1931     }
1932 
1933     for (HInstructionIterator instr_it(block->GetInstructions());
1934          !instr_it.Done();
1935          instr_it.Advance()) {
1936       if (++number_of_instructions >= inlining_budget_) {
1937         LOG_FAIL(stats_, MethodCompilationStat::kNotInlinedInstructionBudget)
1938             << "Method " << callee_dex_file.PrettyMethod(method_index)
1939             << " is not inlined because the outer method has reached"
1940             << " its instruction budget limit.";
1941         return false;
1942       }
1943       HInstruction* current = instr_it.Current();
1944       if (current->NeedsEnvironment() &&
1945           (total_number_of_dex_registers_ >= kMaximumNumberOfCumulatedDexRegisters)) {
1946         LOG_FAIL(stats_, MethodCompilationStat::kNotInlinedEnvironmentBudget)
1947             << "Method " << callee_dex_file.PrettyMethod(method_index)
1948             << " is not inlined because its caller has reached"
1949             << " its environment budget limit.";
1950         return false;
1951       }
1952 
1953       if (current->NeedsEnvironment() &&
1954           !CanEncodeInlinedMethodInStackMap(*caller_compilation_unit_.GetDexFile(),
1955                                             resolved_method)) {
1956         LOG_FAIL(stats_, MethodCompilationStat::kNotInlinedStackMaps)
1957             << "Method " << callee_dex_file.PrettyMethod(method_index)
1958             << " could not be inlined because " << current->DebugName()
1959             << " needs an environment, is in a different dex file"
1960             << ", and cannot be encoded in the stack maps.";
1961         return false;
1962       }
1963 
1964       if (!same_dex_file && current->NeedsDexCacheOfDeclaringClass()) {
1965         LOG_FAIL(stats_, MethodCompilationStat::kNotInlinedDexCache)
1966             << "Method " << callee_dex_file.PrettyMethod(method_index)
1967             << " could not be inlined because " << current->DebugName()
1968             << " it is in a different dex file and requires access to the dex cache";
1969         return false;
1970       }
1971 
1972       if (current->IsUnresolvedStaticFieldGet() ||
1973           current->IsUnresolvedInstanceFieldGet() ||
1974           current->IsUnresolvedStaticFieldSet() ||
1975           current->IsUnresolvedInstanceFieldSet()) {
1976         // Entrypoint for unresolved fields does not handle inlined frames.
1977         LOG_FAIL(stats_, MethodCompilationStat::kNotInlinedUnresolvedEntrypoint)
1978             << "Method " << callee_dex_file.PrettyMethod(method_index)
1979             << " could not be inlined because it is using an unresolved"
1980             << " entrypoint";
1981         return false;
1982       }
1983     }
1984   }
1985 
1986   *out_number_of_instructions = number_of_instructions;
1987   return true;
1988 }
1989 
TryBuildAndInlineHelper(HInvoke * invoke_instruction,ArtMethod * resolved_method,ReferenceTypeInfo receiver_type,HInstruction ** return_replacement)1990 bool HInliner::TryBuildAndInlineHelper(HInvoke* invoke_instruction,
1991                                        ArtMethod* resolved_method,
1992                                        ReferenceTypeInfo receiver_type,
1993                                        HInstruction** return_replacement) {
1994   DCHECK(!(resolved_method->IsStatic() && receiver_type.IsValid()));
1995   const dex::CodeItem* code_item = resolved_method->GetCodeItem();
1996   const DexFile& callee_dex_file = *resolved_method->GetDexFile();
1997   uint32_t method_index = resolved_method->GetDexMethodIndex();
1998   CodeItemDebugInfoAccessor code_item_accessor(resolved_method->DexInstructionDebugInfo());
1999   ClassLinker* class_linker = caller_compilation_unit_.GetClassLinker();
2000   Handle<mirror::DexCache> dex_cache = NewHandleIfDifferent(resolved_method->GetDexCache(),
2001                                                             caller_compilation_unit_.GetDexCache(),
2002                                                             graph_);
2003   Handle<mirror::ClassLoader> class_loader =
2004       NewHandleIfDifferent(resolved_method->GetDeclaringClass()->GetClassLoader(),
2005                            caller_compilation_unit_.GetClassLoader(),
2006                            graph_);
2007 
2008   Handle<mirror::Class> compiling_class =
2009       graph_->GetHandleCache()->NewHandle(resolved_method->GetDeclaringClass());
2010   DexCompilationUnit dex_compilation_unit(
2011       class_loader,
2012       class_linker,
2013       callee_dex_file,
2014       code_item,
2015       resolved_method->GetDeclaringClass()->GetDexClassDefIndex(),
2016       method_index,
2017       resolved_method->GetAccessFlags(),
2018       /* verified_method= */ nullptr,
2019       dex_cache,
2020       compiling_class);
2021 
2022   InvokeType invoke_type = invoke_instruction->GetInvokeType();
2023   if (invoke_type == kInterface) {
2024     // We have statically resolved the dispatch. To please the class linker
2025     // at runtime, we change this call as if it was a virtual call.
2026     invoke_type = kVirtual;
2027   }
2028 
2029   bool caller_dead_reference_safe = graph_->IsDeadReferenceSafe();
2030   const dex::ClassDef& callee_class = resolved_method->GetClassDef();
2031   // MethodContainsRSensitiveAccess is currently slow, but HasDeadReferenceSafeAnnotation()
2032   // is currently rarely true.
2033   bool callee_dead_reference_safe =
2034       annotations::HasDeadReferenceSafeAnnotation(callee_dex_file, callee_class)
2035       && !annotations::MethodContainsRSensitiveAccess(callee_dex_file, callee_class, method_index);
2036 
2037   const int32_t caller_instruction_counter = graph_->GetCurrentInstructionId();
2038   HGraph* callee_graph = new (graph_->GetAllocator()) HGraph(
2039       graph_->GetAllocator(),
2040       graph_->GetArenaStack(),
2041       graph_->GetHandleCache()->GetHandles(),
2042       callee_dex_file,
2043       method_index,
2044       codegen_->GetCompilerOptions().GetInstructionSet(),
2045       invoke_type,
2046       callee_dead_reference_safe,
2047       graph_->IsDebuggable(),
2048       graph_->GetCompilationKind(),
2049       /* start_instruction_id= */ caller_instruction_counter);
2050   callee_graph->SetArtMethod(resolved_method);
2051 
2052   // When they are needed, allocate `inline_stats_` on the Arena instead
2053   // of on the stack, as Clang might produce a stack frame too large
2054   // for this function, that would not fit the requirements of the
2055   // `-Wframe-larger-than` option.
2056   if (stats_ != nullptr) {
2057     // Reuse one object for all inline attempts from this caller to keep Arena memory usage low.
2058     if (inline_stats_ == nullptr) {
2059       void* storage = graph_->GetAllocator()->Alloc<OptimizingCompilerStats>(kArenaAllocMisc);
2060       inline_stats_ = new (storage) OptimizingCompilerStats;
2061     } else {
2062       inline_stats_->Reset();
2063     }
2064   }
2065   HGraphBuilder builder(callee_graph,
2066                         code_item_accessor,
2067                         &dex_compilation_unit,
2068                         &outer_compilation_unit_,
2069                         codegen_,
2070                         inline_stats_,
2071                         resolved_method->GetQuickenedInfo());
2072 
2073   if (builder.BuildGraph() != kAnalysisSuccess) {
2074     LOG_FAIL(stats_, MethodCompilationStat::kNotInlinedCannotBuild)
2075         << "Method " << callee_dex_file.PrettyMethod(method_index)
2076         << " could not be built, so cannot be inlined";
2077     return false;
2078   }
2079 
2080   SubstituteArguments(callee_graph, invoke_instruction, receiver_type, dex_compilation_unit);
2081 
2082   RunOptimizations(callee_graph, code_item, dex_compilation_unit);
2083 
2084   size_t number_of_instructions = 0;
2085   if (!CanInlineBody(callee_graph, invoke_instruction->GetBlock(), &number_of_instructions)) {
2086     return false;
2087   }
2088 
2089   DCHECK_EQ(caller_instruction_counter, graph_->GetCurrentInstructionId())
2090       << "No instructions can be added to the outer graph while inner graph is being built";
2091 
2092   // Inline the callee graph inside the caller graph.
2093   const int32_t callee_instruction_counter = callee_graph->GetCurrentInstructionId();
2094   graph_->SetCurrentInstructionId(callee_instruction_counter);
2095   *return_replacement = callee_graph->InlineInto(graph_, invoke_instruction);
2096   // Update our budget for other inlining attempts in `caller_graph`.
2097   total_number_of_instructions_ += number_of_instructions;
2098   UpdateInliningBudget();
2099 
2100   DCHECK_EQ(callee_instruction_counter, callee_graph->GetCurrentInstructionId())
2101       << "No instructions can be added to the inner graph during inlining into the outer graph";
2102 
2103   if (stats_ != nullptr) {
2104     DCHECK(inline_stats_ != nullptr);
2105     inline_stats_->AddTo(stats_);
2106   }
2107 
2108   if (caller_dead_reference_safe && !callee_dead_reference_safe) {
2109     // Caller was dead reference safe, but is not anymore, since we inlined dead
2110     // reference unsafe code. Prior transformations remain valid, since they did not
2111     // affect the inlined code.
2112     graph_->MarkDeadReferenceUnsafe();
2113   }
2114 
2115   return true;
2116 }
2117 
RunOptimizations(HGraph * callee_graph,const dex::CodeItem * code_item,const DexCompilationUnit & dex_compilation_unit)2118 void HInliner::RunOptimizations(HGraph* callee_graph,
2119                                 const dex::CodeItem* code_item,
2120                                 const DexCompilationUnit& dex_compilation_unit) {
2121   // Note: if the outermost_graph_ is being compiled OSR, we should not run any
2122   // optimization that could lead to a HDeoptimize. The following optimizations do not.
2123   HDeadCodeElimination dce(callee_graph, inline_stats_, "dead_code_elimination$inliner");
2124   HConstantFolding fold(callee_graph, "constant_folding$inliner");
2125   InstructionSimplifier simplify(callee_graph, codegen_, inline_stats_);
2126 
2127   HOptimization* optimizations[] = {
2128     &simplify,
2129     &fold,
2130     &dce,
2131   };
2132 
2133   for (size_t i = 0; i < arraysize(optimizations); ++i) {
2134     HOptimization* optimization = optimizations[i];
2135     optimization->Run();
2136   }
2137 
2138   // Bail early for pathological cases on the environment (for example recursive calls,
2139   // or too large environment).
2140   if (total_number_of_dex_registers_ >= kMaximumNumberOfCumulatedDexRegisters) {
2141     LOG_NOTE() << "Calls in " << callee_graph->GetArtMethod()->PrettyMethod()
2142              << " will not be inlined because the outer method has reached"
2143              << " its environment budget limit.";
2144     return;
2145   }
2146 
2147   // Bail early if we know we already are over the limit.
2148   size_t number_of_instructions = CountNumberOfInstructions(callee_graph);
2149   if (number_of_instructions > inlining_budget_) {
2150     LOG_NOTE() << "Calls in " << callee_graph->GetArtMethod()->PrettyMethod()
2151              << " will not be inlined because the outer method has reached"
2152              << " its instruction budget limit. " << number_of_instructions;
2153     return;
2154   }
2155 
2156   CodeItemDataAccessor accessor(callee_graph->GetDexFile(), code_item);
2157   HInliner inliner(callee_graph,
2158                    outermost_graph_,
2159                    codegen_,
2160                    outer_compilation_unit_,
2161                    dex_compilation_unit,
2162                    inline_stats_,
2163                    total_number_of_dex_registers_ + accessor.RegistersSize(),
2164                    total_number_of_instructions_ + number_of_instructions,
2165                    this,
2166                    depth_ + 1);
2167   inliner.Run();
2168 }
2169 
IsReferenceTypeRefinement(ObjPtr<mirror::Class> declared_class,bool declared_is_exact,bool declared_can_be_null,HInstruction * actual_obj)2170 static bool IsReferenceTypeRefinement(ObjPtr<mirror::Class> declared_class,
2171                                       bool declared_is_exact,
2172                                       bool declared_can_be_null,
2173                                       HInstruction* actual_obj)
2174     REQUIRES_SHARED(Locks::mutator_lock_) {
2175   if (declared_can_be_null && !actual_obj->CanBeNull()) {
2176     return true;
2177   }
2178 
2179   ReferenceTypeInfo actual_rti = actual_obj->GetReferenceTypeInfo();
2180   ObjPtr<mirror::Class> actual_class = actual_rti.GetTypeHandle().Get();
2181   return (actual_rti.IsExact() && !declared_is_exact) ||
2182          (declared_class != actual_class && declared_class->IsAssignableFrom(actual_class));
2183 }
2184 
IsReferenceTypeRefinement(ObjPtr<mirror::Class> declared_class,bool declared_can_be_null,HInstruction * actual_obj)2185 static bool IsReferenceTypeRefinement(ObjPtr<mirror::Class> declared_class,
2186                                       bool declared_can_be_null,
2187                                       HInstruction* actual_obj)
2188     REQUIRES_SHARED(Locks::mutator_lock_) {
2189   bool admissible = ReferenceTypePropagation::IsAdmissible(declared_class);
2190   return IsReferenceTypeRefinement(
2191       admissible ? declared_class : GetClassRoot<mirror::Class>(),
2192       /*declared_is_exact=*/ admissible && declared_class->CannotBeAssignedFromOtherTypes(),
2193       declared_can_be_null,
2194       actual_obj);
2195 }
2196 
ArgumentTypesMoreSpecific(HInvoke * invoke_instruction,ArtMethod * resolved_method)2197 bool HInliner::ArgumentTypesMoreSpecific(HInvoke* invoke_instruction, ArtMethod* resolved_method) {
2198   // If this is an instance call, test whether the type of the `this` argument
2199   // is more specific than the class which declares the method.
2200   if (!resolved_method->IsStatic()) {
2201     if (IsReferenceTypeRefinement(resolved_method->GetDeclaringClass(),
2202                                   /*declared_can_be_null=*/ false,
2203                                   invoke_instruction->InputAt(0u))) {
2204       return true;
2205     }
2206   }
2207 
2208   // Iterate over the list of parameter types and test whether any of the
2209   // actual inputs has a more specific reference type than the type declared in
2210   // the signature.
2211   const dex::TypeList* param_list = resolved_method->GetParameterTypeList();
2212   for (size_t param_idx = 0,
2213               input_idx = resolved_method->IsStatic() ? 0 : 1,
2214               e = (param_list == nullptr ? 0 : param_list->Size());
2215        param_idx < e;
2216        ++param_idx, ++input_idx) {
2217     HInstruction* input = invoke_instruction->InputAt(input_idx);
2218     if (input->GetType() == DataType::Type::kReference) {
2219       ObjPtr<mirror::Class> param_cls = resolved_method->LookupResolvedClassFromTypeIndex(
2220           param_list->GetTypeItem(param_idx).type_idx_);
2221       if (IsReferenceTypeRefinement(param_cls, /*declared_can_be_null=*/ true, input)) {
2222         return true;
2223       }
2224     }
2225   }
2226 
2227   return false;
2228 }
2229 
ReturnTypeMoreSpecific(HInvoke * invoke_instruction,HInstruction * return_replacement)2230 bool HInliner::ReturnTypeMoreSpecific(HInvoke* invoke_instruction,
2231                                       HInstruction* return_replacement) {
2232   // Check the integrity of reference types and run another type propagation if needed.
2233   if (return_replacement != nullptr) {
2234     if (return_replacement->GetType() == DataType::Type::kReference) {
2235       // Test if the return type is a refinement of the declared return type.
2236       ReferenceTypeInfo invoke_rti = invoke_instruction->GetReferenceTypeInfo();
2237       if (IsReferenceTypeRefinement(invoke_rti.GetTypeHandle().Get(),
2238                                     invoke_rti.IsExact(),
2239                                     /*declared_can_be_null=*/ true,
2240                                     return_replacement)) {
2241         return true;
2242       } else if (return_replacement->IsInstanceFieldGet()) {
2243         HInstanceFieldGet* field_get = return_replacement->AsInstanceFieldGet();
2244         if (field_get->GetFieldInfo().GetField() ==
2245                 GetClassRoot<mirror::Object>()->GetInstanceField(0)) {
2246           return true;
2247         }
2248       }
2249     } else if (return_replacement->IsInstanceOf()) {
2250       // Inlining InstanceOf into an If may put a tighter bound on reference types.
2251       return true;
2252     }
2253   }
2254 
2255   return false;
2256 }
2257 
FixUpReturnReferenceType(ArtMethod * resolved_method,HInstruction * return_replacement)2258 void HInliner::FixUpReturnReferenceType(ArtMethod* resolved_method,
2259                                         HInstruction* return_replacement) {
2260   if (return_replacement != nullptr) {
2261     if (return_replacement->GetType() == DataType::Type::kReference) {
2262       if (!return_replacement->GetReferenceTypeInfo().IsValid()) {
2263         // Make sure that we have a valid type for the return. We may get an invalid one when
2264         // we inline invokes with multiple branches and create a Phi for the result.
2265         // TODO: we could be more precise by merging the phi inputs but that requires
2266         // some functionality from the reference type propagation.
2267         DCHECK(return_replacement->IsPhi());
2268         ObjPtr<mirror::Class> cls = resolved_method->LookupResolvedReturnType();
2269         ReferenceTypeInfo rti = ReferenceTypePropagation::IsAdmissible(cls)
2270             ? ReferenceTypeInfo::Create(graph_->GetHandleCache()->NewHandle(cls))
2271             : graph_->GetInexactObjectRti();
2272         return_replacement->SetReferenceTypeInfo(rti);
2273       }
2274     }
2275   }
2276 }
2277 
2278 }  // namespace art
2279