Clean up encoding of size and single entry flag in Instructions.

runtime/vm/object.h

 // Copyright (c) 2012, 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.
 
 #ifndef RUNTIME_VM_OBJECT_H_
 #define RUNTIME_VM_OBJECT_H_
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "platform/utils.h"
@@ skipping 3994 matching lines @@
 
   FINAL_HEAP_OBJECT_IMPLEMENTATION(ObjectPool, Object);
   friend class Class;
   friend class Object;
   friend class RawObjectPool;
 };
 
 
 class Instructions : public Object {
  public:
+  enum {
+    kSizePos = 0,
+    kSizeSize = 31,
+    kFlagsPos = kSizePos + kSizeSize,
+    kFlagsSize = 1,  // Currently, only flag is single entry flag.
+  };
+
+  class SizeBits : public BitField<uint32_t, uint32_t, kSizePos, kSizeSize> {};
+  class FlagsBits : public BitField<uint32_t, bool, kFlagsPos, kFlagsSize> {};
+
   // Excludes HeaderSize().
-  intptr_t size() const { return abs(raw_ptr()->size_); }
-  bool HasSingleEntryPoint() const { return raw_ptr()->size_ >= 0; }
+  intptr_t Size() const { return SizeBits::decode(raw_ptr()->size_and_flags_); }
+  static intptr_t Size(const RawInstructions* instr) {
+    return SizeBits::decode(instr->ptr()->size_and_flags_);
+  }
+
+  bool HasSingleEntryPoint() const {
+    return FlagsBits::decode(raw_ptr()->size_and_flags_);
+  }
+  static bool HasSingleEntryPoint(const RawInstructions* instr) {
+    return FlagsBits::decode(instr->ptr()->size_and_flags_);
+  }
 
   uword PayloadStart() const { return PayloadStart(raw()); }
   uword CheckedEntryPoint() const { return CheckedEntryPoint(raw()); }
   uword UncheckedEntryPoint() const { return UncheckedEntryPoint(raw()); }
-  static uword PayloadStart(RawInstructions* instr) {
+  static uword PayloadStart(const RawInstructions* instr) {
     return reinterpret_cast<uword>(instr->ptr()) + HeaderSize();
   }
 
 #if defined(TARGET_ARCH_IA32)
   static const intptr_t kCheckedEntryOffset = 0;
   static const intptr_t kUncheckedEntryOffset = 0;
 #elif defined(TARGET_ARCH_X64)
   static const intptr_t kCheckedEntryOffset = 16;
   static const intptr_t kUncheckedEntryOffset = 38;
 #elif defined(TARGET_ARCH_ARM)
   static const intptr_t kCheckedEntryOffset = 8;
   static const intptr_t kUncheckedEntryOffset = 32;
 #elif defined(TARGET_ARCH_ARM64)
   static const intptr_t kCheckedEntryOffset = 16;
   static const intptr_t kUncheckedEntryOffset = 40;
 #elif defined(TARGET_ARCH_MIPS)
   static const intptr_t kCheckedEntryOffset = 12;
   static const intptr_t kUncheckedEntryOffset = 52;
 #elif defined(TARGET_ARCH_DBC)
   static const intptr_t kCheckedEntryOffset = 0;
   static const intptr_t kUncheckedEntryOffset = 0;
 #else
 #error Missing entry offsets for current architecture
 #endif
 
-  static uword CheckedEntryPoint(RawInstructions* instr) {
+  static uword CheckedEntryPoint(const RawInstructions* instr) {
     uword entry = PayloadStart(instr);
-    if (instr->ptr()->size_ < 0) {
+    if (!HasSingleEntryPoint(instr)) {
       entry += kCheckedEntryOffset;
     }
     return entry;
   }
-  static uword UncheckedEntryPoint(RawInstructions* instr) {
+  static uword UncheckedEntryPoint(const RawInstructions* instr) {
     uword entry = PayloadStart(instr);
-    if (instr->ptr()->size_ < 0) {
+    if (!HasSingleEntryPoint(instr)) {
       entry += kUncheckedEntryOffset;
     }
     return entry;
   }
 
   static const intptr_t kMaxElements =
       (kMaxInt32 - (sizeof(RawInstructions) + sizeof(RawObject) +
                     (2 * OS::kMaxPreferredCodeAlignment)));
 
   static intptr_t InstanceSize() {
@@ skipping 14 matching lines @@
     intptr_t alignment = OS::PreferredCodeAlignment();
     return Utils::RoundUp(sizeof(RawInstructions), alignment);
   }
 
   static RawInstructions* FromPayloadStart(uword payload_start) {
     return reinterpret_cast<RawInstructions*>(payload_start - HeaderSize() +
                                               kHeapObjectTag);
   }
 
   bool Equals(const Instructions& other) const {
-    if (size() != other.size()) {
+    if (Size() != other.Size()) {
       return false;
     }
     NoSafepointScope no_safepoint;
-    return memcmp(raw_ptr(), other.raw_ptr(), InstanceSize(size())) == 0;
+    return memcmp(raw_ptr(), other.raw_ptr(), InstanceSize(Size())) == 0;
   }
 
  private:
-  void set_size(intptr_t size) const {
-    StoreNonPointer(&raw_ptr()->size_, size);
+  void SetSize(intptr_t value) const {
+    ASSERT(value >= 0);
+    StoreNonPointer(&raw_ptr()->size_and_flags_,
+                    SizeBits::update(value, raw_ptr()->size_and_flags_));
+  }
+
+  void SetHasSingleEntryPoint(bool value) const {
+    StoreNonPointer(&raw_ptr()->size_and_flags_,
+                    FlagsBits::update(value, raw_ptr()->size_and_flags_));
   }
 
   // New is a private method as RawInstruction and RawCode objects should
   // only be created using the Code::FinalizeCode method. This method creates
   // the RawInstruction and RawCode objects, sets up the pointer offsets
   // and links the two in a GC safe manner.
   static RawInstructions* New(intptr_t size, bool has_single_entry_point);
 
   FINAL_HEAP_OBJECT_IMPLEMENTATION(Instructions, Object);
   friend class Class;
@@ skipping 454 matching lines @@
   uword UncheckedEntryPoint() const {
     const Instructions& instr = Instructions::Handle(instructions());
     return instr.UncheckedEntryPoint();
   }
   uword CheckedEntryPoint() const {
     const Instructions& instr = Instructions::Handle(instructions());
     return instr.CheckedEntryPoint();
   }
   intptr_t Size() const {
     const Instructions& instr = Instructions::Handle(instructions());
-    return instr.size();
+    return instr.Size();
   }
   RawObjectPool* GetObjectPool() const { return object_pool(); }
   bool ContainsInstructionAt(uword addr) const {
     const Instructions& instr = Instructions::Handle(instructions());
     const uword offset = addr - instr.PayloadStart();
-    return offset < static_cast<uword>(instr.size());
+    return offset < static_cast<uword>(instr.Size());
   }
 
   // Returns true if there is a debugger breakpoint set in this code object.
   bool HasBreakpoint() const;
 
   RawPcDescriptors* pc_descriptors() const {
     return raw_ptr()->pc_descriptors_;
   }
   void set_pc_descriptors(const PcDescriptors& descriptors) const {
     ASSERT(descriptors.IsOld());
@@ skipping 4196 matching lines @@
 
 inline void TypeArguments::SetHash(intptr_t value) const {
   // This is only safe because we create a new Smi, which does not cause
   // heap allocation.
   StoreSmi(&raw_ptr()->hash_, Smi::New(value));
 }
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_OBJECT_H_