commit 28e012a4af2d710e5e5f824709ffd6432e4f549f
author Vladimir Marko <vmarko@google.com> Thu Dec 07 11:22:59 2017 +0000
committer Vladimir Marko <vmarko@google.com> Fri Dec 08 15:27:27 2017 +0000
tree 576ebdbff9d5f9f098cd29d652215b8f67b6b042
parent 4388fb213ec746ee18a6bea38ee894f8c19990b9

Determine HLoadClass/String load kind early.

This helps save memory by avoiding the allocation of
HEnvironment and related objects for AOT references to
boot image strings and classes (kBootImage* load kinds)
and also for JIT references (kJitTableAddress).

Compiling aosp_taimen-userdebug boot image, the most memory
hungry method BatteryStats.dumpLocked() needs
  - before:
    Used 55105384 bytes of arena memory...
    ...
    UseListNode    10009704
    Environment      423248
    EnvVRegs       20676560
    ...
  - after:
    Used 50559176 bytes of arena memory...
    ...
    UseListNode     8568936
    Environment      365680
    EnvVRegs       17628704
    ...

Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing --jit
Bug: 34053922
Change-Id: I68e73a438e6ac8e8908e6fccf53bbeea8a64a077

compiler/optimizing/instruction_builder.cc

diff --git a/compiler/optimizing/instruction_builder.cc b/compiler/optimizing/instruction_builder.cc
index 782546c..4485f06 100644
--- a/compiler/optimizing/instruction_builder.cc
+++ b/compiler/optimizing/instruction_builder.cc
@@ -1128,7 +1128,7 @@
       MethodCompilationStat::kConstructorFenceGeneratedNew);
 }
 
-static bool IsSubClass(mirror::Class* to_test, mirror::Class* super_class)
+static bool IsSubClass(ObjPtr<mirror::Class> to_test, ObjPtr<mirror::Class> super_class)
     REQUIRES_SHARED(Locks::mutator_lock_) {
   return to_test != nullptr && !to_test->IsInterface() && to_test->IsSubClass(super_class);
 }
@@ -1424,7 +1424,7 @@
   return true;
 }
 
-static mirror::Class* GetClassFrom(CompilerDriver* driver,
+static ObjPtr<mirror::Class> GetClassFrom(CompilerDriver* driver,
                                    const DexCompilationUnit& compilation_unit) {
   ScopedObjectAccess soa(Thread::Current());
   Handle<mirror::ClassLoader> class_loader = compilation_unit.GetClassLoader();
@@ -1433,11 +1433,11 @@
   return driver->ResolveCompilingMethodsClass(soa, dex_cache, class_loader, &compilation_unit);
 }
 
-mirror::Class* HInstructionBuilder::GetOutermostCompilingClass() const {
+ObjPtr<mirror::Class> HInstructionBuilder::GetOutermostCompilingClass() const {
   return GetClassFrom(compiler_driver_, *outer_compilation_unit_);
 }
 
-mirror::Class* HInstructionBuilder::GetCompilingClass() const {
+ObjPtr<mirror::Class> HInstructionBuilder::GetCompilingClass() const {
   return GetClassFrom(compiler_driver_, *dex_compilation_unit_);
 }
 
@@ -1799,6 +1799,17 @@
   }
 }
 
+void HInstructionBuilder::BuildLoadString(dex::StringIndex string_index, uint32_t dex_pc) {
+  HLoadString* load_string =
+      new (allocator_) HLoadString(graph_->GetCurrentMethod(), string_index, *dex_file_, dex_pc);
+  HSharpening::ProcessLoadString(load_string,
+                                 code_generator_,
+                                 compiler_driver_,
+                                 *dex_compilation_unit_,
+                                 handles_);
+  AppendInstruction(load_string);
+}
+
 HLoadClass* HInstructionBuilder::BuildLoadClass(dex::TypeIndex type_index, uint32_t dex_pc) {
   ScopedObjectAccess soa(Thread::Current());
   const DexFile& dex_file = *dex_compilation_unit_->GetDexFile();
@@ -1811,7 +1822,7 @@
     if (klass->IsPublic()) {
       needs_access_check = false;
     } else {
-      mirror::Class* compiling_class = GetCompilingClass();
+      ObjPtr<mirror::Class> compiling_class = GetCompilingClass();
       if (compiling_class != nullptr && compiling_class->CanAccess(klass.Get())) {
         needs_access_check = false;
       }
@@ -1856,9 +1867,9 @@
     // We actually cannot reference this class, we're forced to bail.
     return nullptr;
   }
-  // Append the instruction first, as setting the load kind affects the inputs.
-  AppendInstruction(load_class);
+  // Load kind must be set before inserting the instruction into the graph.
   load_class->SetLoadKind(load_kind);
+  AppendInstruction(load_class);
   return load_class;
 }
 
@@ -2837,20 +2848,14 @@
 
     case Instruction::CONST_STRING: {
       dex::StringIndex string_index(instruction.VRegB_21c());
-      AppendInstruction(new (allocator_) HLoadString(graph_->GetCurrentMethod(),
-                                                     string_index,
-                                                     *dex_file_,
-                                                     dex_pc));
+      BuildLoadString(string_index, dex_pc);
       UpdateLocal(instruction.VRegA_21c(), current_block_->GetLastInstruction());
       break;
     }
 
     case Instruction::CONST_STRING_JUMBO: {
       dex::StringIndex string_index(instruction.VRegB_31c());
-      AppendInstruction(new (allocator_) HLoadString(graph_->GetCurrentMethod(),
-                                                     string_index,
-                                                     *dex_file_,
-                                                     dex_pc));
+      BuildLoadString(string_index, dex_pc);
       UpdateLocal(instruction.VRegA_31c(), current_block_->GetLastInstruction());
       break;
     }