Add near calls (32-bit displacement) to Code objects on X64 platform.

src/x64/assembler-x64.h

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // All Rights Reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 // - Redistributions of source code must retain the above copyright notice,
 // this list of conditions and the following disclaimer.
 //
@@ skipping 422 matching lines @@
   // is too small, a fatal error occurs. No deallocation of the buffer is done
   // upon destruction of the assembler.
   Assembler(void* buffer, int buffer_size);
   ~Assembler();
 
   // GetCode emits any pending (non-emitted) code and fills the descriptor
   // desc. GetCode() is idempotent; it returns the same result if no other
   // Assembler functions are invoked in between GetCode() calls.
   void GetCode(CodeDesc* desc);
 
-  // Read/Modify the code target in the branch/call instruction at pc.
-  // On the x64 architecture, the address is absolute, not relative.
+  // Read/Modify the code target in the relative branch/call instruction at pc.
+  // On the x64 architecture, we use relative jumps with a 32-bit displacement
+  // to jump to other Code objects in the Code space in the heap.
+  // Jumps to C functions are done indirectly through a 64-bit register holding
+  // the absolute address of the target.
+  // These functions convert between absolute Addresses of Code objects and
+  // the relative displacements stored in the code.
   static inline Address target_address_at(Address pc);
   static inline void set_target_address_at(Address pc, Address target);
-
+  inline Handle<Object> code_target_object_handle_at(Address pc);
   // Distance between the address of the code target in the call instruction
-  // and the return address.  Checked in the debug build.
-  static const int kCallTargetAddressOffset = 3 + kPointerSize;
-  // Distance between start of patched return sequence and the emitted address
-  // to jump to (movq = REX.W 0xB8+r.).
-  static const int kPatchReturnSequenceAddressOffset = 2;
-
+  // and the return address pushed on the stack.
+  static const int kCallTargetAddressOffset = 4;  // Use 32-bit displacement.
+  // Distance between the start of the JS return sequence and where the
+  // 32-bit displacement of a near call would be, relative to the pushed
+  // return address.  TODO: Use return sequence length instead.
+  // Should equal Debug::kX64JSReturnSequenceLength - kCallTargetAddressOffset;
+  static const int kPatchReturnSequenceAddressOffset = 13 - 4;
+  // TODO(X64): Rename this, removing the "Real", after changing the above.
+  static const int kRealPatchReturnSequenceAddressOffset = 2;
   // ---------------------------------------------------------------------------
   // Code generation
   //
   // Function names correspond one-to-one to x64 instruction mnemonics.
   // Unless specified otherwise, instructions operate on 64-bit operands.
   //
   // If we need versions of an assembly instruction that operate on different
   // width arguments, we add a single-letter suffix specifying the width.
   // This is done for the following instructions: mov, cmp, inc, dec,
   // add, sub, and test.
@@ skipping 451 matching lines @@
   // bind(&L);   // illegal: a label may be bound only once
   //
   // Note: The same Label can be used for forward and backward branches
   // but it may be bound only once.
 
   void bind(Label* L);  // binds an unbound label L to the current code position
 
   // Calls
   // Call near relative 32-bit displacement, relative to next instruction.
   void call(Label* L);
+  void call(Handle<Code> target, RelocInfo::Mode rmode);
 
   // Call near absolute indirect, address in register
   void call(Register adr);
 
   // Call near indirect
   void call(const Operand& operand);
 
   // Jumps
   // Jump short or near relative.
+  // Use a 32-bit signed displacement.
   void jmp(Label* L);  // unconditional jump to L
+  void jmp(Handle<Code> target, RelocInfo::Mode rmode);
 
   // Jump near absolute indirect (r64)
   void jmp(Register adr);
 
   // Jump near absolute indirect (m64)
   void jmp(const Operand& src);
 
   // Conditional jumps
   void j(Condition cc, Label* L);
+  void j(Condition cc, Handle<Code> target, RelocInfo::Mode rmode);
 
   // Floating-point operations
   void fld(int i);
 
   void fld1();
   void fldz();
 
   void fld_s(const Operand& adr);
   void fld_d(const Operand& adr);
 
@@ skipping 85 matching lines @@
   void RecordJSReturn();
 
   // Record a comment relocation entry that can be used by a disassembler.
   // Use --debug_code to enable.
   void RecordComment(const char* msg);
 
   void RecordPosition(int pos);
   void RecordStatementPosition(int pos);
   void WriteRecordedPositions();
 
-  // Writes a doubleword of data in the code stream.
-  // Used for inline tables, e.g., jump-tables.
-  // void dd(uint32_t data);
-
-  // Writes a quadword of data in the code stream.
-  // Used for inline tables, e.g., jump-tables.
-  // void dd(uint64_t data, RelocInfo::Mode reloc_info);
-
   int pc_offset() const  { return pc_ - buffer_; }
   int current_statement_position() const { return current_statement_position_; }
   int current_position() const  { return current_position_; }
 
   // Check if there is less than kGap bytes available in the buffer.
   // If this is the case, we need to grow the buffer before emitting
   // an instruction or relocation information.
   inline bool buffer_overflow() const {
     return pc_ >= reloc_info_writer.pos() - kGap;
   }
@@ skipping 21 matching lines @@
   }
   void long_at_put(int pos, uint32_t x)  {
     *reinterpret_cast<uint32_t*>(addr_at(pos)) = x;
   }
 
   // code emission
   void GrowBuffer();
 
   void emit(byte x) { *pc_++ = x; }
   inline void emitl(uint32_t x);
-  inline void emit(Handle<Object> handle);
   inline void emitq(uint64_t x, RelocInfo::Mode rmode);
   inline void emitw(uint16_t x);
+  inline void emit_code_target(Handle<Code> target, RelocInfo::Mode rmode);
   void emit(Immediate x) { emitl(x.value_); }
 
   // Emits a REX prefix that encodes a 64-bit operand size and
   // the top bit of both register codes.
   // High bit of reg goes to REX.R, high bit of rm_reg goes to REX.B.
   // REX.W is set.
   inline void emit_rex_64(Register reg, Register rm_reg);
   inline void emit_rex_64(XMMRegister reg, Register rm_reg);
 
   // Emits a REX prefix that encodes a 64-bit operand size and
@@ skipping 157 matching lines @@
   int buffer_size_;
   // True if the assembler owns the buffer, false if buffer is external.
   bool own_buffer_;
   // A previously allocated buffer of kMinimalBufferSize bytes, or NULL.
   static byte* spare_buffer_;
 
   // code generation
   byte* pc_;  // the program counter; moves forward
   RelocInfoWriter reloc_info_writer;
 
+  List< Handle<Code> > code_targets_;
   // push-pop elimination
   byte* last_pc_;
 
   // source position information
   int current_statement_position_;
   int current_position_;
   int written_statement_position_;
   int written_position_;
 };
 
@@ skipping 21 matching lines @@
  private:
   Assembler* assembler_;
 #ifdef DEBUG
   int space_before_;
 #endif
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_ASSEMBLER_X64_H_