Fill Class and String .bss slots in runtime.

Shift the responsibility for filling Class and String .bss
slots from compiled code to runtime. This reduces the size
of the compiled code.

Make oatdump list .bss slot mappings (ArtMethod, Class and
String) for each dex file.

aosp_taimen-userdebug boot image size:
  - before:
    arm boot*.oat: 36534524
    arm64 boot*.oat: 42723256
  - after:
    arm boot*.oat: 36431448 (-101KiB, -0.3%)
    arm64 boot*.oat: 42645016 (-76KiB, -0.2%)

Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Test: Pixel 2 XL boots.
Test: testrunner.py --target --optimizing
Test: m dump-oat, manually inspect output.
Bug: 65737953
Change-Id: I1330d070307410107e12c309d4c7f8121baba83c

1 files changed, 13 insertions, 118 deletions

diff --git a/compiler/optimizing/code_generator_mips.cc b/compiler/optimizing/code_generator_mips.cc
index ddec0cc453..d6922d2f3f 100644
--- a/compiler/optimizing/code_generator_mips.cc
+++ b/compiler/optimizing/code_generator_mips.cc
@@ -220,13 +220,11 @@ class LoadClassSlowPathMIPS : public SlowPathCodeMIPS {
   LoadClassSlowPathMIPS(HLoadClass* cls,
                         HInstruction* at,
                         uint32_t dex_pc,
-                        bool do_clinit,
-                        const CodeGeneratorMIPS::PcRelativePatchInfo* bss_info_high = nullptr)
+                        bool do_clinit)
       : SlowPathCodeMIPS(at),
         cls_(cls),
         dex_pc_(dex_pc),
-        do_clinit_(do_clinit),
-        bss_info_high_(bss_info_high) {
+        do_clinit_(do_clinit) {
     DCHECK(at->IsLoadClass() || at->IsClinitCheck());
   }
 
@@ -234,28 +232,11 @@ class LoadClassSlowPathMIPS : public SlowPathCodeMIPS {
     LocationSummary* locations = instruction_->GetLocations();
     Location out = locations->Out();
     CodeGeneratorMIPS* mips_codegen = down_cast<CodeGeneratorMIPS*>(codegen);
-    const bool baker_or_no_read_barriers = (!kUseReadBarrier || kUseBakerReadBarrier);
     InvokeRuntimeCallingConvention calling_convention;
     DCHECK_EQ(instruction_->IsLoadClass(), cls_ == instruction_);
-    const bool is_load_class_bss_entry =
-        (cls_ == instruction_) && (cls_->GetLoadKind() == HLoadClass::LoadKind::kBssEntry);
     __ Bind(GetEntryLabel());
     SaveLiveRegisters(codegen, locations);
 
-    // For HLoadClass/kBssEntry/kSaveEverything, make sure we preserve the address of the entry.
-    Register entry_address = kNoRegister;
-    if (is_load_class_bss_entry && baker_or_no_read_barriers) {
-      Register temp = locations->GetTemp(0).AsRegister<Register>();
-      bool temp_is_a0 = (temp == calling_convention.GetRegisterAt(0));
-      // In the unlucky case that `temp` is A0, we preserve the address in `out` across the
-      // kSaveEverything call.
-      entry_address = temp_is_a0 ? out.AsRegister<Register>() : temp;
-      DCHECK_NE(entry_address, calling_convention.GetRegisterAt(0));
-      if (temp_is_a0) {
-        __ Move(entry_address, temp);
-      }
-    }
-
     dex::TypeIndex type_index = cls_->GetTypeIndex();
     __ LoadConst32(calling_convention.GetRegisterAt(0), type_index.index_);
     QuickEntrypointEnum entrypoint = do_clinit_ ? kQuickInitializeStaticStorage
@@ -267,18 +248,6 @@ class LoadClassSlowPathMIPS : public SlowPathCodeMIPS {
       CheckEntrypointTypes<kQuickInitializeType, void*, uint32_t>();
     }
 
-    // For HLoadClass/kBssEntry, store the resolved class to the BSS entry.
-    if (is_load_class_bss_entry && baker_or_no_read_barriers) {
-      // The class entry address was preserved in `entry_address` thanks to kSaveEverything.
-      DCHECK(bss_info_high_);
-      CodeGeneratorMIPS::PcRelativePatchInfo* info_low =
-          mips_codegen->NewTypeBssEntryPatch(cls_->GetDexFile(), type_index, bss_info_high_);
-      __ Sw(calling_convention.GetRegisterAt(0),
-            entry_address,
-            /* placeholder */ 0x5678,
-            &info_low->label);
-    }
-
     // Move the class to the desired location.
     if (out.IsValid()) {
       DCHECK(out.IsRegister() && !locations->GetLiveRegisters()->ContainsCoreRegister(out.reg()));
@@ -289,21 +258,6 @@ class LoadClassSlowPathMIPS : public SlowPathCodeMIPS {
     }
     RestoreLiveRegisters(codegen, locations);
 
-    // For HLoadClass/kBssEntry, store the resolved class to the BSS entry.
-    if (is_load_class_bss_entry && !baker_or_no_read_barriers) {
-      // For non-Baker read barriers we need to re-calculate the address of
-      // the class entry.
-      const bool isR6 = mips_codegen->GetInstructionSetFeatures().IsR6();
-      const bool has_irreducible_loops = codegen->GetGraph()->HasIrreducibleLoops();
-      Register base =
-          (isR6 || has_irreducible_loops) ? ZERO : locations->InAt(0).AsRegister<Register>();
-      CodeGeneratorMIPS::PcRelativePatchInfo* info_high =
-          mips_codegen->NewTypeBssEntryPatch(cls_->GetDexFile(), type_index);
-      CodeGeneratorMIPS::PcRelativePatchInfo* info_low =
-          mips_codegen->NewTypeBssEntryPatch(cls_->GetDexFile(), type_index, info_high);
-      mips_codegen->EmitPcRelativeAddressPlaceholderHigh(info_high, TMP, base);
-      __ Sw(out.AsRegister<Register>(), TMP, /* placeholder */ 0x5678, &info_low->label);
-    }
     __ B(GetExitLabel());
   }
 
@@ -319,92 +273,41 @@ class LoadClassSlowPathMIPS : public SlowPathCodeMIPS {
   // Whether to initialize the class.
   const bool do_clinit_;
 
-  // Pointer to the high half PC-relative patch info for HLoadClass/kBssEntry.
-  const CodeGeneratorMIPS::PcRelativePatchInfo* bss_info_high_;
-
   DISALLOW_COPY_AND_ASSIGN(LoadClassSlowPathMIPS);
 };
 
 class LoadStringSlowPathMIPS : public SlowPathCodeMIPS {
  public:
-  explicit LoadStringSlowPathMIPS(HLoadString* instruction,
-                                  const CodeGeneratorMIPS::PcRelativePatchInfo* bss_info_high)
-      : SlowPathCodeMIPS(instruction), bss_info_high_(bss_info_high) {}
+  explicit LoadStringSlowPathMIPS(HLoadString* instruction)
+      : SlowPathCodeMIPS(instruction) {}
 
   void EmitNativeCode(CodeGenerator* codegen) OVERRIDE {
     DCHECK(instruction_->IsLoadString());
     DCHECK_EQ(instruction_->AsLoadString()->GetLoadKind(), HLoadString::LoadKind::kBssEntry);
     LocationSummary* locations = instruction_->GetLocations();
     DCHECK(!locations->GetLiveRegisters()->ContainsCoreRegister(locations->Out().reg()));
-    HLoadString* load = instruction_->AsLoadString();
-    const dex::StringIndex string_index = load->GetStringIndex();
-    Register out = locations->Out().AsRegister<Register>();
+    const dex::StringIndex string_index = instruction_->AsLoadString()->GetStringIndex();
     CodeGeneratorMIPS* mips_codegen = down_cast<CodeGeneratorMIPS*>(codegen);
-    const bool baker_or_no_read_barriers = (!kUseReadBarrier || kUseBakerReadBarrier);
     InvokeRuntimeCallingConvention calling_convention;
     __ Bind(GetEntryLabel());
     SaveLiveRegisters(codegen, locations);
 
-    // For HLoadString/kBssEntry/kSaveEverything, make sure we preserve the address of the entry.
-    Register entry_address = kNoRegister;
-    if (baker_or_no_read_barriers) {
-      Register temp = locations->GetTemp(0).AsRegister<Register>();
-      bool temp_is_a0 = (temp == calling_convention.GetRegisterAt(0));
-      // In the unlucky case that `temp` is A0, we preserve the address in `out` across the
-      // kSaveEverything call.
-      entry_address = temp_is_a0 ? out : temp;
-      DCHECK_NE(entry_address, calling_convention.GetRegisterAt(0));
-      if (temp_is_a0) {
-        __ Move(entry_address, temp);
-      }
-    }
-
     __ LoadConst32(calling_convention.GetRegisterAt(0), string_index.index_);
     mips_codegen->InvokeRuntime(kQuickResolveString, instruction_, instruction_->GetDexPc(), this);
     CheckEntrypointTypes<kQuickResolveString, void*, uint32_t>();
 
-    // Store the resolved string to the BSS entry.
-    if (baker_or_no_read_barriers) {
-      // The string entry address was preserved in `entry_address` thanks to kSaveEverything.
-      DCHECK(bss_info_high_);
-      CodeGeneratorMIPS::PcRelativePatchInfo* info_low =
-          mips_codegen->NewStringBssEntryPatch(load->GetDexFile(), string_index, bss_info_high_);
-      __ Sw(calling_convention.GetRegisterAt(0),
-            entry_address,
-            /* placeholder */ 0x5678,
-            &info_low->label);
-    }
-
     DataType::Type type = instruction_->GetType();
     mips_codegen->MoveLocation(locations->Out(),
                                Location::RegisterLocation(calling_convention.GetRegisterAt(0)),
                                type);
     RestoreLiveRegisters(codegen, locations);
 
-    // Store the resolved string to the BSS entry.
-    if (!baker_or_no_read_barriers) {
-      // For non-Baker read barriers we need to re-calculate the address of
-      // the string entry.
-      const bool isR6 = mips_codegen->GetInstructionSetFeatures().IsR6();
-      const bool has_irreducible_loops = codegen->GetGraph()->HasIrreducibleLoops();
-      Register base =
-          (isR6 || has_irreducible_loops) ? ZERO : locations->InAt(0).AsRegister<Register>();
-      CodeGeneratorMIPS::PcRelativePatchInfo* info_high =
-          mips_codegen->NewStringBssEntryPatch(load->GetDexFile(), string_index);
-      CodeGeneratorMIPS::PcRelativePatchInfo* info_low =
-          mips_codegen->NewStringBssEntryPatch(load->GetDexFile(), string_index, info_high);
-      mips_codegen->EmitPcRelativeAddressPlaceholderHigh(info_high, TMP, base);
-      __ Sw(out, TMP, /* placeholder */ 0x5678, &info_low->label);
-    }
     __ B(GetExitLabel());
   }
 
   const char* GetDescription() const OVERRIDE { return "LoadStringSlowPathMIPS"; }
 
  private:
-  // Pointer to the high half PC-relative patch info.
-  const CodeGeneratorMIPS::PcRelativePatchInfo* bss_info_high_;
-
   DISALLOW_COPY_AND_ASSIGN(LoadStringSlowPathMIPS);
 };
 
@@ -7736,8 +7639,6 @@ void LocationsBuilderMIPS::VisitLoadClass(HLoadClass* cls) {
   if (load_kind == HLoadClass::LoadKind::kBssEntry) {
     if (!kUseReadBarrier || kUseBakerReadBarrier) {
       // Rely on the type resolution or initialization and marking to save everything we need.
-      // Request a temp to hold the BSS entry location for the slow path.
-      locations->AddTemp(Location::RequiresRegister());
       RegisterSet caller_saves = RegisterSet::Empty();
       InvokeRuntimeCallingConvention calling_convention;
       caller_saves.Add(Location::RegisterLocation(calling_convention.GetRegisterAt(0)));
@@ -7786,7 +7687,6 @@ void InstructionCodeGeneratorMIPS::VisitLoadClass(HLoadClass* cls) NO_THREAD_SAF
       ? kWithoutReadBarrier
       : kCompilerReadBarrierOption;
   bool generate_null_check = false;
-  CodeGeneratorMIPS::PcRelativePatchInfo* bss_info_high = nullptr;
   switch (load_kind) {
     case HLoadClass::LoadKind::kReferrersClass: {
       DCHECK(!cls->CanCallRuntime());
@@ -7845,17 +7745,16 @@ void InstructionCodeGeneratorMIPS::VisitLoadClass(HLoadClass* cls) NO_THREAD_SAF
       break;
     }
     case HLoadClass::LoadKind::kBssEntry: {
-      bss_info_high = codegen_->NewTypeBssEntryPatch(cls->GetDexFile(), cls->GetTypeIndex());
+      CodeGeneratorMIPS::PcRelativePatchInfo* bss_info_high =
+          codegen_->NewTypeBssEntryPatch(cls->GetDexFile(), cls->GetTypeIndex());
       CodeGeneratorMIPS::PcRelativePatchInfo* info_low =
           codegen_->NewTypeBssEntryPatch(cls->GetDexFile(), cls->GetTypeIndex(), bss_info_high);
-      constexpr bool non_baker_read_barrier = kUseReadBarrier && !kUseBakerReadBarrier;
-      Register temp = non_baker_read_barrier ? out : locations->GetTemp(0).AsRegister<Register>();
       codegen_->EmitPcRelativeAddressPlaceholderHigh(bss_info_high,
-                                                     temp,
+                                                     out,
                                                      base_or_current_method_reg);
       GenerateGcRootFieldLoad(cls,
                               out_loc,
-                              temp,
+                              out,
                               /* placeholder */ 0x5678,
                               read_barrier_option,
                               &info_low->label);
@@ -7887,7 +7786,7 @@ void InstructionCodeGeneratorMIPS::VisitLoadClass(HLoadClass* cls) NO_THREAD_SAF
   if (generate_null_check || cls->MustGenerateClinitCheck()) {
     DCHECK(cls->CanCallRuntime());
     SlowPathCodeMIPS* slow_path = new (codegen_->GetScopedAllocator()) LoadClassSlowPathMIPS(
-        cls, cls, cls->GetDexPc(), cls->MustGenerateClinitCheck(), bss_info_high);
+        cls, cls, cls->GetDexPc(), cls->MustGenerateClinitCheck());
     codegen_->AddSlowPath(slow_path);
     if (generate_null_check) {
       __ Beqz(out, slow_path->GetEntryLabel());
@@ -7960,8 +7859,6 @@ void LocationsBuilderMIPS::VisitLoadString(HLoadString* load) {
     if (load_kind == HLoadString::LoadKind::kBssEntry) {
       if (!kUseReadBarrier || kUseBakerReadBarrier) {
         // Rely on the pResolveString and marking to save everything we need.
-        // Request a temp to hold the BSS entry location for the slow path.
-        locations->AddTemp(Location::RequiresRegister());
         RegisterSet caller_saves = RegisterSet::Empty();
         InvokeRuntimeCallingConvention calling_convention;
         caller_saves.Add(Location::RegisterLocation(calling_convention.GetRegisterAt(0)));
@@ -8041,19 +7938,17 @@ void InstructionCodeGeneratorMIPS::VisitLoadString(HLoadString* load) NO_THREAD_
           codegen_->NewStringBssEntryPatch(load->GetDexFile(), load->GetStringIndex());
       CodeGeneratorMIPS::PcRelativePatchInfo* info_low =
           codegen_->NewStringBssEntryPatch(load->GetDexFile(), load->GetStringIndex(), info_high);
-      constexpr bool non_baker_read_barrier = kUseReadBarrier && !kUseBakerReadBarrier;
-      Register temp = non_baker_read_barrier ? out : locations->GetTemp(0).AsRegister<Register>();
       codegen_->EmitPcRelativeAddressPlaceholderHigh(info_high,
-                                                     temp,
+                                                     out,
                                                      base_or_current_method_reg);
       GenerateGcRootFieldLoad(load,
                               out_loc,
-                              temp,
+                              out,
                               /* placeholder */ 0x5678,
                               kCompilerReadBarrierOption,
                               &info_low->label);
       SlowPathCodeMIPS* slow_path =
-          new (codegen_->GetScopedAllocator()) LoadStringSlowPathMIPS(load, info_high);
+          new (codegen_->GetScopedAllocator()) LoadStringSlowPathMIPS(load);
       codegen_->AddSlowPath(slow_path);
       __ Beqz(out, slow_path->GetEntryLabel());
       __ Bind(slow_path->GetExitLabel());