Support untagged object pool entries.

runtime/vm/assembler_x64.cc

Index: runtime/vm/assembler_x64.cc
diff --git a/runtime/vm/assembler_x64.cc b/runtime/vm/assembler_x64.cc
index 45a0754cde9852e760755f48f93c902e2061bc8f..3fb782b2a43748684c4e6e81fc296e5477c7cd77 100644
--- a/runtime/vm/assembler_x64.cc
+++ b/runtime/vm/assembler_x64.cc
@@ -22,7 +22,7 @@ DECLARE_FLAG(bool, inline_alloc);
 
 
 Assembler::Assembler(bool use_far_branches)
-    : buffer_(),
+    : buffer_(this),
       prologue_offset_(-1),
       comments_(),
       allow_constant_pool_(true) {
@@ -33,29 +33,27 @@ Assembler::Assembler(bool use_far_branches)
     // 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);
     }
   }
 }
@@ -98,6 +96,7 @@ void Assembler::LoadExternalLabel(Register dst,
   const int32_t offset =
       Array::element_offset(object_pool_.FindExternalLabel(label, patchable));
   LoadWordFromPoolOffset(dst, pp, offset - kHeapObjectTag);
+  EmitFixup(new ObjectPoolIndexFixup());
 }
 
 
@@ -119,16 +118,20 @@ void Assembler::CallPatchable(const ExternalLabel* label) {
       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());
+    }
   }
 }
 
@@ -2612,13 +2615,15 @@ void Assembler::JmpPatchable(const ExternalLabel* label, Register pp) {
   // 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());
 }
 
 
@@ -2817,7 +2822,7 @@ void Assembler::LoadIsolate(Register dst) {
 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()) ||
@@ -2852,7 +2857,7 @@ void Assembler::PushObject(const Object& object, Register 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(
@@ -2863,8 +2868,8 @@ void Assembler::CompareObject(Register reg, const Object& object, Register 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);
 }
 
 
@@ -3064,7 +3069,8 @@ void Assembler::StoreIntoObject(Register object,
     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);
 }