Support untagged object pool entries.

runtime/vm/assembler_x64.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // NOLINT
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/assembler.h"
 #include "vm/cpu.h"
 #include "vm/heap.h"
 #include "vm/instructions.h"
 #include "vm/locations.h"
 #include "vm/memory_region.h"
 #include "vm/runtime_entry.h"
 #include "vm/stack_frame.h"
 #include "vm/stub_code.h"
 
 namespace dart {
 
 DEFINE_FLAG(bool, print_stop_message, true, "Print stop message.");
 DECLARE_FLAG(bool, inline_alloc);
 
 
 Assembler::Assembler(bool use_far_branches)
-    : buffer_(),
+    : buffer_(this),
       prologue_offset_(-1),
       comments_(),
       allow_constant_pool_(true) {
   // Far branching mode is only needed and implemented for MIPS and ARM.
   ASSERT(!use_far_branches);
   Isolate* isolate = Isolate::Current();
   if (isolate != Dart::vm_isolate()) {
     // These objects and labels need to be accessible through every pool-pointer
     // at the same index.
     intptr_t index =
-        object_pool_.AddObject(Object::null_object(), kNotPatchable);
+        object_pool_.AddFixedObject(Object::null_object());

[Florian Schneider, 2015/05/26 08:51:51]

I'm considering removing all fixed objects / stubs from the object pools. First,
this saves space in places where those are not used. Second, it simplifies would
simplify this new implementation of the constant pool.

[srdjan, 2015/05/26 22:36:26]

Where would you load them from?

     ASSERT(index == 0);
 
-    index = object_pool_.AddObject(Bool::True(), kNotPatchable);
+    index = object_pool_.AddFixedObject(Bool::True());
     ASSERT(index == 1);
 
-    index = object_pool_.AddObject(Bool::False(), kNotPatchable);
+    index = object_pool_.AddFixedObject(Bool::False());
     ASSERT(index == 2);
 
-    const Smi& vacant = Smi::Handle(Smi::New(0xfa >> kSmiTagShift));
+    const Smi& vacant = Smi::ZoneHandle(Smi::New(0xfa >> kSmiTagShift));
     StubCode* stub_code = isolate->stub_code();
     if (stub_code->UpdateStoreBuffer_entry() != NULL) {
-      object_pool_.AddExternalLabel(&stub_code->UpdateStoreBufferLabel(),
-                                    kNotPatchable);
+      object_pool_.AddFixedExternalLabel(&stub_code->UpdateStoreBufferLabel());
     } else {
-      object_pool_.AddObject(vacant, kNotPatchable);
+      object_pool_.AddFixedObject(vacant);
     }
 
     if (stub_code->CallToRuntime_entry() != NULL) {
-      object_pool_.AddExternalLabel(&stub_code->CallToRuntimeLabel(),
-                                    kNotPatchable);
+      object_pool_.AddFixedExternalLabel(&stub_code->CallToRuntimeLabel());
     } else {
-      object_pool_.AddObject(vacant, kNotPatchable);
+      object_pool_.AddFixedObject(vacant);
     }
   }
 }
 
 
 void Assembler::InitializeMemoryWithBreakpoints(uword data, intptr_t length) {
   memset(reinterpret_cast<void*>(data), Instr::kBreakPointInstruction, length);
 }
 
 
@@ skipping 22 matching lines @@
 }
 
 
 void Assembler::LoadExternalLabel(Register dst,
                                   const ExternalLabel* label,
                                   Patchability patchable,
                                   Register pp) {
   const int32_t offset =
       Array::element_offset(object_pool_.FindExternalLabel(label, patchable));
   LoadWordFromPoolOffset(dst, pp, offset - kHeapObjectTag);
+  EmitFixup(new ObjectPoolIndexFixup());
 }
 
 
 void Assembler::call(const ExternalLabel* label) {
   {  // Encode movq(TMP, Immediate(label->address())), but always as imm64.
     AssemblerBuffer::EnsureCapacity ensured(&buffer_);
     EmitRegisterREX(TMP, REX_W);
     EmitUint8(0xB8 | (TMP & 7));
     EmitInt64(label->address());
   }
   call(TMP);
 }
 
 
 void Assembler::CallPatchable(const ExternalLabel* label) {
   ASSERT(allow_constant_pool());
   intptr_t call_start = buffer_.GetPosition();
   const int32_t offset =
       Array::element_offset(object_pool_.FindExternalLabel(label, kPatchable));
   call(Address::AddressBaseImm32(PP, offset - kHeapObjectTag));
   ASSERT((buffer_.GetPosition() - call_start) == kCallExternalLabelSize);
+  EmitFixup(new ObjectPoolIndexFixup());
 }
 
 
-void Assembler::Call(const ExternalLabel* label, Register pp) {
+void Assembler::Call(const ExternalLabel* label, Register pp, bool emit_fixup) {
   if (Isolate::Current() == Dart::vm_isolate()) {
     call(label);
   } else {
     const int32_t offset = Array::element_offset(
         object_pool_.FindExternalLabel(label, kNotPatchable));
     call(Address::AddressBaseImm32(pp, offset - kHeapObjectTag));
+    if (emit_fixup) {
+      EmitFixup(new ObjectPoolIndexFixup());
+    }
   }
 }
 
 
 void Assembler::pushq(Register reg) {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   EmitRegisterREX(reg, REX_NONE);
   EmitUint8(0x50 | (reg & 7));
 }
 
@@ skipping 2463 matching lines @@
 
 
 void Assembler::JmpPatchable(const ExternalLabel* label, Register pp) {
   ASSERT(allow_constant_pool());
   intptr_t call_start = buffer_.GetPosition();
   const int32_t offset =
       Array::element_offset(object_pool_.FindExternalLabel(label, kPatchable));
   // Patchable jumps always use a 32-bit immediate encoding.
   jmp(Address::AddressBaseImm32(pp, offset - kHeapObjectTag));
   ASSERT((buffer_.GetPosition() - call_start) == JumpPattern::kLengthInBytes);
+  EmitFixup(new ObjectPoolIndexFixup());
 }
 
 
 void Assembler::Jmp(const ExternalLabel* label, Register pp) {
   const int32_t offset = Array::element_offset(
       object_pool_.FindExternalLabel(label, kNotPatchable));
-  jmp(Address(pp, offset - kHeapObjectTag));
+  jmp(Address::AddressBaseImm32(pp, offset - kHeapObjectTag));
+  EmitFixup(new ObjectPoolIndexFixup());
 }
 
 
 void Assembler::lock() {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   EmitUint8(0xF0);
 }
 
 
 void Assembler::cmpxchgl(const Address& address, Register reg) {
@@ skipping 178 matching lines @@
 
 
 void Assembler::LoadIsolate(Register dst) {
   movq(dst, Immediate(reinterpret_cast<uword>(Isolate::Current())));
 }
 
 
 void Assembler::LoadObject(Register dst, const Object& object, Register pp) {
   if (CanLoadFromObjectPool(object)) {
     const int32_t offset =
-        Array::element_offset(object_pool_.FindObject(object, kNotPatchable));
+        Array::element_offset(object_pool_.FindObject(object));
     LoadWordFromPoolOffset(dst, pp, offset - kHeapObjectTag);
   } else {
     ASSERT((Isolate::Current() == Dart::vm_isolate()) ||
            object.IsSmi() ||
            object.InVMHeap());
     LoadImmediate(dst, Immediate(reinterpret_cast<int64_t>(object.raw())), pp);
   }
 }
 
 
@@ skipping 14 matching lines @@
     pushq(TMP);
   } else {
     PushImmediate(Immediate(reinterpret_cast<int64_t>(object.raw())), pp);
   }
 }
 
 
 void Assembler::CompareObject(Register reg, const Object& object, Register pp) {
   if (CanLoadFromObjectPool(object)) {
     const int32_t offset =
-        Array::element_offset(object_pool_.FindObject(object, kNotPatchable));
+        Array::element_offset(object_pool_.FindObject(object));
     cmpq(reg, Address(pp, offset-kHeapObjectTag));
   } else {
     CompareImmediate(
         reg, Immediate(reinterpret_cast<int64_t>(object.raw())), pp);
   }
 }
 
 
 intptr_t Assembler::FindImmediate(int64_t imm) {
   ASSERT(Isolate::Current() != Dart::vm_isolate());
-  const Smi& smi = Smi::Handle(reinterpret_cast<RawSmi*>(imm));
-  return object_pool_.FindObject(smi, kNotPatchable);
+  const Smi& smi = Smi::ZoneHandle(reinterpret_cast<RawSmi*>(imm));
+  return object_pool_.FindObject(smi);
 }
 
 
 bool Assembler::CanLoadImmediateFromPool(const Immediate& imm, Register pp) {
   if (!allow_constant_pool()) {
     return false;
   }
   return !imm.is_int32() &&
          (pp != kNoRegister) &&
          (Isolate::Current() != Dart::vm_isolate());
@@ skipping 179 matching lines @@
     StoreIntoObjectFilter(object, value, &done);
   } else {
     StoreIntoObjectFilterNoSmi(object, value, &done);
   }
   // A store buffer update is required.
   if (value != RDX) pushq(RDX);
   if (object != RDX) {
     movq(RDX, object);
   }
   StubCode* stub_code = Isolate::Current()->stub_code();
-  Call(&stub_code->UpdateStoreBufferLabel(), PP);
+  Call(&stub_code->UpdateStoreBufferLabel(), PP,
+       false);  // No fixup. Stub is at a fixed place in the object pool.
   if (value != RDX) popq(RDX);
   Bind(&done);
 }
 
 
 void Assembler::StoreIntoObjectNoBarrier(Register object,
                                          const Address& dest,
                                          Register value,
                                          FieldContent old_content) {
   VerifiedWrite(dest, value, old_content);
@@ skipping 818 matching lines @@
 
 
 const char* Assembler::FpuRegisterName(FpuRegister reg) {
   ASSERT((0 <= reg) && (reg < kNumberOfXmmRegisters));
   return xmm_reg_names[reg];
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64