Use dex cache from compilation unit in HInstructionBuilder.

Avoid calling costly ClassLinker::FindDexCache() from
HInstructionBuilder, the dex cache is already available in
the compilation unit. Compiling Nexus 5 boot image on host
under perf(1) shows that the time spent in FindDexCache()
is reduced from about 2% to well under 0.2%, 90% of the
remaining hits coming from ReferenceTypePropagation which
doesn't have access to the compilation unit.

Change-Id: Id9df61c79db9a67e3f12c857f32a4ca80e5420c3
diff --git a/compiler/driver/compiler_driver.cc b/compiler/driver/compiler_driver.cc
index 8bdff21..be82956 100644
--- a/compiler/driver/compiler_driver.cc
+++ b/compiler/driver/compiler_driver.cc
@@ -1283,14 +1283,13 @@
   return IsImageClass(descriptor);
 }
 
-bool CompilerDriver::CanAssumeTypeIsPresentInDexCache(const DexFile& dex_file, uint32_t type_idx) {
+bool CompilerDriver::CanAssumeTypeIsPresentInDexCache(Handle<mirror::DexCache> dex_cache,
+                                                      uint32_t type_idx) {
   bool result = false;
   if ((IsBootImage() &&
-       IsImageClass(dex_file.StringDataByIdx(dex_file.GetTypeId(type_idx).descriptor_idx_))) ||
+       IsImageClass(dex_cache->GetDexFile()->StringDataByIdx(
+           dex_cache->GetDexFile()->GetTypeId(type_idx).descriptor_idx_))) ||
       Runtime::Current()->UseJit()) {
-    ScopedObjectAccess soa(Thread::Current());
-    mirror::DexCache* dex_cache = Runtime::Current()->GetClassLinker()->FindDexCache(
-        soa.Self(), dex_file, false);
     mirror::Class* resolved_class = dex_cache->GetResolvedType(type_idx);
     result = (resolved_class != nullptr);
   }
@@ -1332,32 +1331,16 @@
   return result;
 }
 
-bool CompilerDriver::CanAccessTypeWithoutChecks(uint32_t referrer_idx, const DexFile& dex_file,
-                                                uint32_t type_idx,
-                                                bool* type_known_final, bool* type_known_abstract,
-                                                bool* equals_referrers_class) {
-  if (type_known_final != nullptr) {
-    *type_known_final = false;
-  }
-  if (type_known_abstract != nullptr) {
-    *type_known_abstract = false;
-  }
-  if (equals_referrers_class != nullptr) {
-    *equals_referrers_class = false;
-  }
-  ScopedObjectAccess soa(Thread::Current());
-  mirror::DexCache* dex_cache = Runtime::Current()->GetClassLinker()->FindDexCache(
-      soa.Self(), dex_file, false);
+bool CompilerDriver::CanAccessTypeWithoutChecks(uint32_t referrer_idx,
+                                                Handle<mirror::DexCache> dex_cache,
+                                                uint32_t type_idx) {
   // Get type from dex cache assuming it was populated by the verifier
   mirror::Class* resolved_class = dex_cache->GetResolvedType(type_idx);
   if (resolved_class == nullptr) {
     stats_->TypeNeedsAccessCheck();
     return false;  // Unknown class needs access checks.
   }
-  const DexFile::MethodId& method_id = dex_file.GetMethodId(referrer_idx);
-  if (equals_referrers_class != nullptr) {
-    *equals_referrers_class = (method_id.class_idx_ == type_idx);
-  }
+  const DexFile::MethodId& method_id = dex_cache->GetDexFile()->GetMethodId(referrer_idx);
   bool is_accessible = resolved_class->IsPublic();  // Public classes are always accessible.
   if (!is_accessible) {
     mirror::Class* referrer_class = dex_cache->GetResolvedType(method_id.class_idx_);
@@ -1371,12 +1354,6 @@
   }
   if (is_accessible) {
     stats_->TypeDoesntNeedAccessCheck();
-    if (type_known_final != nullptr) {
-      *type_known_final = resolved_class->IsFinal() && !resolved_class->IsArrayClass();
-    }
-    if (type_known_abstract != nullptr) {
-      *type_known_abstract = resolved_class->IsAbstract() && !resolved_class->IsArrayClass();
-    }
   } else {
     stats_->TypeNeedsAccessCheck();
   }
@@ -1384,12 +1361,9 @@
 }
 
 bool CompilerDriver::CanAccessInstantiableTypeWithoutChecks(uint32_t referrer_idx,
-                                                            const DexFile& dex_file,
+                                                            Handle<mirror::DexCache> dex_cache,
                                                             uint32_t type_idx,
                                                             bool* finalizable) {
-  ScopedObjectAccess soa(Thread::Current());
-  mirror::DexCache* dex_cache = Runtime::Current()->GetClassLinker()->FindDexCache(
-      soa.Self(), dex_file, false);
   // Get type from dex cache assuming it was populated by the verifier.
   mirror::Class* resolved_class = dex_cache->GetResolvedType(type_idx);
   if (resolved_class == nullptr) {
@@ -1399,7 +1373,7 @@
     return false;  // Unknown class needs access checks.
   }
   *finalizable = resolved_class->IsFinalizable();
-  const DexFile::MethodId& method_id = dex_file.GetMethodId(referrer_idx);
+  const DexFile::MethodId& method_id = dex_cache->GetDexFile()->GetMethodId(referrer_idx);
   bool is_accessible = resolved_class->IsPublic();  // Public classes are always accessible.
   if (!is_accessible) {
     mirror::Class* referrer_class = dex_cache->GetResolvedType(method_id.class_idx_);
@@ -1587,53 +1561,6 @@
   }
 }
 
-bool CompilerDriver::ComputeStaticFieldInfo(uint32_t field_idx, const DexCompilationUnit* mUnit,
-                                            bool is_put, MemberOffset* field_offset,
-                                            uint32_t* storage_index, bool* is_referrers_class,
-                                            bool* is_volatile, bool* is_initialized,
-                                            Primitive::Type* type) {
-  ScopedObjectAccess soa(Thread::Current());
-  // Try to resolve the field and compiling method's class.
-  ArtField* resolved_field;
-  mirror::Class* referrer_class;
-  Handle<mirror::DexCache> dex_cache(mUnit->GetDexCache());
-  {
-    StackHandleScope<1> hs(soa.Self());
-    Handle<mirror::ClassLoader> class_loader_handle(
-        hs.NewHandle(soa.Decode<mirror::ClassLoader*>(mUnit->GetClassLoader())));
-    resolved_field =
-        ResolveField(soa, dex_cache, class_loader_handle, mUnit, field_idx, true);
-    referrer_class = resolved_field != nullptr
-        ? ResolveCompilingMethodsClass(soa, dex_cache, class_loader_handle, mUnit) : nullptr;
-  }
-  bool result = false;
-  if (resolved_field != nullptr && referrer_class != nullptr) {
-    *is_volatile = IsFieldVolatile(resolved_field);
-    std::pair<bool, bool> fast_path = IsFastStaticField(
-        dex_cache.Get(), referrer_class, resolved_field, field_idx, storage_index);
-    result = is_put ? fast_path.second : fast_path.first;
-  }
-  if (result) {
-    *field_offset = GetFieldOffset(resolved_field);
-    *is_referrers_class = IsStaticFieldInReferrerClass(referrer_class, resolved_field);
-    // *is_referrers_class == true implies no worrying about class initialization.
-    *is_initialized = (*is_referrers_class) ||
-        (IsStaticFieldsClassInitialized(referrer_class, resolved_field) &&
-         CanAssumeTypeIsPresentInDexCache(*mUnit->GetDexFile(), *storage_index));
-    *type = resolved_field->GetTypeAsPrimitiveType();
-  } else {
-    // Conservative defaults.
-    *is_volatile = true;
-    *field_offset = MemberOffset(static_cast<size_t>(-1));
-    *storage_index = -1;
-    *is_referrers_class = false;
-    *is_initialized = false;
-    *type = Primitive::kPrimVoid;
-  }
-  ProcessedStaticField(result, *is_referrers_class);
-  return result;
-}
-
 void CompilerDriver::GetCodeAndMethodForDirectCall(InvokeType* type, InvokeType sharp_type,
                                                    bool no_guarantee_of_dex_cache_entry,
                                                    const mirror::Class* referrer_class,
diff --git a/compiler/driver/compiler_driver.h b/compiler/driver/compiler_driver.h
index 4308eac..d63dffa 100644
--- a/compiler/driver/compiler_driver.h
+++ b/compiler/driver/compiler_driver.h
@@ -195,25 +195,26 @@
 
   // Callbacks from compiler to see what runtime checks must be generated.
 
-  bool CanAssumeTypeIsPresentInDexCache(const DexFile& dex_file, uint32_t type_idx);
+  bool CanAssumeTypeIsPresentInDexCache(Handle<mirror::DexCache> dex_cache,
+                                        uint32_t type_idx)
+      SHARED_REQUIRES(Locks::mutator_lock_);
 
   bool CanAssumeStringIsPresentInDexCache(const DexFile& dex_file, uint32_t string_idx)
       REQUIRES(!Locks::mutator_lock_);
 
   // Are runtime access checks necessary in the compiled code?
-  bool CanAccessTypeWithoutChecks(uint32_t referrer_idx, const DexFile& dex_file,
-                                  uint32_t type_idx, bool* type_known_final = nullptr,
-                                  bool* type_known_abstract = nullptr,
-                                  bool* equals_referrers_class = nullptr)
-      REQUIRES(!Locks::mutator_lock_);
+  bool CanAccessTypeWithoutChecks(uint32_t referrer_idx,
+                                  Handle<mirror::DexCache> dex_cache,
+                                  uint32_t type_idx)
+      SHARED_REQUIRES(Locks::mutator_lock_);
 
   // Are runtime access and instantiable checks necessary in the code?
   // out_is_finalizable is set to whether the type is finalizable.
   bool CanAccessInstantiableTypeWithoutChecks(uint32_t referrer_idx,
-                                              const DexFile& dex_file,
+                                              Handle<mirror::DexCache> dex_cache,
                                               uint32_t type_idx,
                                               bool* out_is_finalizable)
-      REQUIRES(!Locks::mutator_lock_);
+      SHARED_REQUIRES(Locks::mutator_lock_);
 
   bool CanEmbedTypeInCode(const DexFile& dex_file, uint32_t type_idx,
                           bool* is_type_initialized, bool* use_direct_type_ptr,
@@ -368,14 +369,6 @@
       SHARED_REQUIRES(Locks::mutator_lock_);
 
 
-  // Can we fastpath static field access? Computes field's offset, volatility and whether the
-  // field is within the referrer (which can avoid checking class initialization).
-  bool ComputeStaticFieldInfo(uint32_t field_idx, const DexCompilationUnit* mUnit, bool is_put,
-                              MemberOffset* field_offset, uint32_t* storage_index,
-                              bool* is_referrers_class, bool* is_volatile, bool* is_initialized,
-                              Primitive::Type* type)
-      REQUIRES(!Locks::mutator_lock_);
-
   // Can we fastpath a interface, super class or virtual method call? Computes method's vtable
   // index.
   bool ComputeInvokeInfo(const DexCompilationUnit* mUnit, const uint32_t dex_pc,
diff --git a/compiler/optimizing/instruction_builder.cc b/compiler/optimizing/instruction_builder.cc
index 06b3968..f5e49c2 100644
--- a/compiler/optimizing/instruction_builder.cc
+++ b/compiler/optimizing/instruction_builder.cc
@@ -889,8 +889,15 @@
 }
 
 bool HInstructionBuilder::BuildNewInstance(uint16_t type_index, uint32_t dex_pc) {
+  ScopedObjectAccess soa(Thread::Current());
+  StackHandleScope<1> hs(soa.Self());
+  Handle<mirror::DexCache> dex_cache = dex_compilation_unit_->GetDexCache();
+  Handle<mirror::Class> resolved_class(hs.NewHandle(dex_cache->GetResolvedType(type_index)));
+  const DexFile& outer_dex_file = *outer_compilation_unit_->GetDexFile();
+  Handle<mirror::DexCache> outer_dex_cache = outer_compilation_unit_->GetDexCache();
+
   bool finalizable;
-  bool can_throw = NeedsAccessCheck(type_index, &finalizable);
+  bool can_throw = NeedsAccessCheck(type_index, dex_cache, &finalizable);
 
   // Only the non-resolved entrypoint handles the finalizable class case. If we
   // need access checks, then we haven't resolved the method and the class may
@@ -899,16 +906,6 @@
       ? kQuickAllocObject
       : kQuickAllocObjectInitialized;
 
-  ScopedObjectAccess soa(Thread::Current());
-  StackHandleScope<3> hs(soa.Self());
-  Handle<mirror::DexCache> dex_cache(hs.NewHandle(
-      dex_compilation_unit_->GetClassLinker()->FindDexCache(
-          soa.Self(), *dex_compilation_unit_->GetDexFile())));
-  Handle<mirror::Class> resolved_class(hs.NewHandle(dex_cache->GetResolvedType(type_index)));
-  const DexFile& outer_dex_file = *outer_compilation_unit_->GetDexFile();
-  Handle<mirror::DexCache> outer_dex_cache(hs.NewHandle(
-      outer_compilation_unit_->GetClassLinker()->FindDexCache(soa.Self(), outer_dex_file)));
-
   if (outer_dex_cache.Get() != dex_cache.Get()) {
     // We currently do not support inlining allocations across dex files.
     return false;
@@ -921,7 +918,7 @@
       IsOutermostCompilingClass(type_index),
       dex_pc,
       /*needs_access_check*/ can_throw,
-      compiler_driver_->CanAssumeTypeIsPresentInDexCache(outer_dex_file, type_index));
+      compiler_driver_->CanAssumeTypeIsPresentInDexCache(outer_dex_cache, type_index));
 
   AppendInstruction(load_class);
   HInstruction* cls = load_class;
@@ -979,13 +976,9 @@
       HInvokeStaticOrDirect::ClinitCheckRequirement* clinit_check_requirement) {
   const DexFile& outer_dex_file = *outer_compilation_unit_->GetDexFile();
   Thread* self = Thread::Current();
-  StackHandleScope<4> hs(self);
-  Handle<mirror::DexCache> dex_cache(hs.NewHandle(
-      dex_compilation_unit_->GetClassLinker()->FindDexCache(
-          self, *dex_compilation_unit_->GetDexFile())));
-  Handle<mirror::DexCache> outer_dex_cache(hs.NewHandle(
-      outer_compilation_unit_->GetClassLinker()->FindDexCache(
-          self, outer_dex_file)));
+  StackHandleScope<2> hs(self);
+  Handle<mirror::DexCache> dex_cache = dex_compilation_unit_->GetDexCache();
+  Handle<mirror::DexCache> outer_dex_cache = outer_compilation_unit_->GetDexCache();
   Handle<mirror::Class> outer_class(hs.NewHandle(GetOutermostCompilingClass()));
   Handle<mirror::Class> resolved_method_class(hs.NewHandle(resolved_method->GetDeclaringClass()));
 
@@ -1016,7 +1009,7 @@
         is_outer_class,
         dex_pc,
         /*needs_access_check*/ false,
-        compiler_driver_->CanAssumeTypeIsPresentInDexCache(outer_dex_file, storage_index));
+        compiler_driver_->CanAssumeTypeIsPresentInDexCache(outer_dex_cache, storage_index));
     AppendInstruction(load_class);
     clinit_check = new (arena_) HClinitCheck(load_class, dex_pc);
     AppendInstruction(clinit_check);
@@ -1261,12 +1254,10 @@
 static mirror::Class* GetClassFrom(CompilerDriver* driver,
                                    const DexCompilationUnit& compilation_unit) {
   ScopedObjectAccess soa(Thread::Current());
-  StackHandleScope<2> hs(soa.Self());
-  const DexFile& dex_file = *compilation_unit.GetDexFile();
+  StackHandleScope<1> hs(soa.Self());
   Handle<mirror::ClassLoader> class_loader(hs.NewHandle(
       soa.Decode<mirror::ClassLoader*>(compilation_unit.GetClassLoader())));
-  Handle<mirror::DexCache> dex_cache(hs.NewHandle(
-      compilation_unit.GetClassLinker()->FindDexCache(soa.Self(), dex_file)));
+  Handle<mirror::DexCache> dex_cache = compilation_unit.GetDexCache();
 
   return driver->ResolveCompilingMethodsClass(soa, dex_cache, class_loader, &compilation_unit);
 }
@@ -1281,10 +1272,8 @@
 
 bool HInstructionBuilder::IsOutermostCompilingClass(uint16_t type_index) const {
   ScopedObjectAccess soa(Thread::Current());
-  StackHandleScope<4> hs(soa.Self());
-  Handle<mirror::DexCache> dex_cache(hs.NewHandle(
-      dex_compilation_unit_->GetClassLinker()->FindDexCache(
-          soa.Self(), *dex_compilation_unit_->GetDexFile())));
+  StackHandleScope<3> hs(soa.Self());
+  Handle<mirror::DexCache> dex_cache = dex_compilation_unit_->GetDexCache();
   Handle<mirror::ClassLoader> class_loader(hs.NewHandle(
       soa.Decode<mirror::ClassLoader*>(dex_compilation_unit_->GetClassLoader())));
   Handle<mirror::Class> cls(hs.NewHandle(compiler_driver_->ResolveClass(
@@ -1324,10 +1313,8 @@
   uint16_t field_index = instruction.VRegB_21c();
 
   ScopedObjectAccess soa(Thread::Current());
-  StackHandleScope<5> hs(soa.Self());
-  Handle<mirror::DexCache> dex_cache(hs.NewHandle(
-      dex_compilation_unit_->GetClassLinker()->FindDexCache(
-          soa.Self(), *dex_compilation_unit_->GetDexFile())));
+  StackHandleScope<3> hs(soa.Self());
+  Handle<mirror::DexCache> dex_cache = dex_compilation_unit_->GetDexCache();
   Handle<mirror::ClassLoader> class_loader(hs.NewHandle(
       soa.Decode<mirror::ClassLoader*>(dex_compilation_unit_->GetClassLoader())));
   ArtField* resolved_field = compiler_driver_->ResolveField(
@@ -1342,8 +1329,7 @@
 
   Primitive::Type field_type = resolved_field->GetTypeAsPrimitiveType();
   const DexFile& outer_dex_file = *outer_compilation_unit_->GetDexFile();
-  Handle<mirror::DexCache> outer_dex_cache(hs.NewHandle(
-      outer_compilation_unit_->GetClassLinker()->FindDexCache(soa.Self(), outer_dex_file)));
+  Handle<mirror::DexCache> outer_dex_cache = outer_compilation_unit_->GetDexCache();
   Handle<mirror::Class> outer_class(hs.NewHandle(GetOutermostCompilingClass()));
 
   // The index at which the field's class is stored in the DexCache's type array.
@@ -1371,7 +1357,7 @@
   }
 
   bool is_in_cache =
-      compiler_driver_->CanAssumeTypeIsPresentInDexCache(outer_dex_file, storage_index);
+      compiler_driver_->CanAssumeTypeIsPresentInDexCache(outer_dex_cache, storage_index);
   HLoadClass* constant = new (arena_) HLoadClass(graph_->GetCurrentMethod(),
                                                  storage_index,
                                                  outer_dex_file,
@@ -1634,21 +1620,16 @@
                                          uint8_t reference,
                                          uint16_t type_index,
                                          uint32_t dex_pc) {
-  bool type_known_final, type_known_abstract, use_declaring_class;
+  ScopedObjectAccess soa(Thread::Current());
+  StackHandleScope<1> hs(soa.Self());
+  const DexFile& dex_file = *dex_compilation_unit_->GetDexFile();
+  Handle<mirror::DexCache> dex_cache = dex_compilation_unit_->GetDexCache();
+  Handle<mirror::Class> resolved_class(hs.NewHandle(dex_cache->GetResolvedType(type_index)));
+
   bool can_access = compiler_driver_->CanAccessTypeWithoutChecks(
       dex_compilation_unit_->GetDexMethodIndex(),
-      *dex_compilation_unit_->GetDexFile(),
-      type_index,
-      &type_known_final,
-      &type_known_abstract,
-      &use_declaring_class);
-
-  ScopedObjectAccess soa(Thread::Current());
-  StackHandleScope<2> hs(soa.Self());
-  const DexFile& dex_file = *dex_compilation_unit_->GetDexFile();
-  Handle<mirror::DexCache> dex_cache(hs.NewHandle(
-      dex_compilation_unit_->GetClassLinker()->FindDexCache(soa.Self(), dex_file)));
-  Handle<mirror::Class> resolved_class(hs.NewHandle(dex_cache->GetResolvedType(type_index)));
+      dex_cache,
+      type_index);
 
   HInstruction* object = LoadLocal(reference, Primitive::kPrimNot);
   HLoadClass* cls = new (arena_) HLoadClass(
@@ -1658,7 +1639,7 @@
       IsOutermostCompilingClass(type_index),
       dex_pc,
       !can_access,
-      compiler_driver_->CanAssumeTypeIsPresentInDexCache(dex_file, type_index));
+      compiler_driver_->CanAssumeTypeIsPresentInDexCache(dex_cache, type_index));
   AppendInstruction(cls);
 
   TypeCheckKind check_kind = ComputeTypeCheckKind(resolved_class);
@@ -1676,9 +1657,17 @@
   }
 }
 
-bool HInstructionBuilder::NeedsAccessCheck(uint32_t type_index, bool* finalizable) const {
+bool HInstructionBuilder::NeedsAccessCheck(uint32_t type_index,
+                                           Handle<mirror::DexCache> dex_cache,
+                                           bool* finalizable) const {
   return !compiler_driver_->CanAccessInstantiableTypeWithoutChecks(
-      dex_compilation_unit_->GetDexMethodIndex(), *dex_file_, type_index, finalizable);
+      dex_compilation_unit_->GetDexMethodIndex(), dex_cache, type_index, finalizable);
+}
+
+bool HInstructionBuilder::NeedsAccessCheck(uint32_t type_index, bool* finalizable) const {
+  ScopedObjectAccess soa(Thread::Current());
+  Handle<mirror::DexCache> dex_cache = dex_compilation_unit_->GetDexCache();
+  return NeedsAccessCheck(type_index, dex_cache, finalizable);
 }
 
 bool HInstructionBuilder::CanDecodeQuickenedInfo() const {
@@ -2612,16 +2601,16 @@
 
     case Instruction::CONST_CLASS: {
       uint16_t type_index = instruction.VRegB_21c();
-      bool type_known_final;
-      bool type_known_abstract;
-      bool dont_use_is_referrers_class;
       // `CanAccessTypeWithoutChecks` will tell whether the method being
       // built is trying to access its own class, so that the generated
       // code can optimize for this case. However, the optimization does not
       // work for inlining, so we use `IsOutermostCompilingClass` instead.
+      ScopedObjectAccess soa(Thread::Current());
+      Handle<mirror::DexCache> dex_cache = dex_compilation_unit_->GetDexCache();
       bool can_access = compiler_driver_->CanAccessTypeWithoutChecks(
-          dex_compilation_unit_->GetDexMethodIndex(), *dex_file_, type_index,
-          &type_known_final, &type_known_abstract, &dont_use_is_referrers_class);
+          dex_compilation_unit_->GetDexMethodIndex(), dex_cache, type_index);
+      bool is_in_dex_cache =
+          compiler_driver_->CanAssumeTypeIsPresentInDexCache(dex_cache, type_index);
       AppendInstruction(new (arena_) HLoadClass(
           graph_->GetCurrentMethod(),
           type_index,
@@ -2629,7 +2618,7 @@
           IsOutermostCompilingClass(type_index),
           dex_pc,
           !can_access,
-          compiler_driver_->CanAssumeTypeIsPresentInDexCache(*dex_file_, type_index)));
+          is_in_dex_cache));
       UpdateLocal(instruction.VRegA_21c(), current_block_->GetLastInstruction());
       break;
     }
diff --git a/compiler/optimizing/instruction_builder.h b/compiler/optimizing/instruction_builder.h
index f480b70..070f7da 100644
--- a/compiler/optimizing/instruction_builder.h
+++ b/compiler/optimizing/instruction_builder.h
@@ -97,6 +97,10 @@
 
   // Returns whether the current method needs access check for the type.
   // Output parameter finalizable is set to whether the type is finalizable.
+  bool NeedsAccessCheck(uint32_t type_index,
+                        Handle<mirror::DexCache> dex_cache,
+                        /*out*/bool* finalizable) const
+      SHARED_REQUIRES(Locks::mutator_lock_);
   bool NeedsAccessCheck(uint32_t type_index, /*out*/bool* finalizable) const;
 
   template<typename T>