v8/src/macro-assembler-ia32.h

// Copyright 2006-2008 the V8 project authors. All rights reserved.
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// modification, are permitted provided that the following conditions are
// met:
//
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#ifndef V8_MACRO_ASSEMBLER_IA32_H_
#define V8_MACRO_ASSEMBLER_IA32_H_

#include "assembler.h"

namespace v8 { namespace internal {

// Forward declaration.
class JumpTarget;


// Helper types to make flags easier to read at call sites.
enum InvokeFlag {
  CALL_FUNCTION,
  JUMP_FUNCTION
};

enum CodeLocation {
  IN_JAVASCRIPT,
  IN_JS_ENTRY,
  IN_C_ENTRY
};

enum HandlerType {
  TRY_CATCH_HANDLER,
  TRY_FINALLY_HANDLER,
  JS_ENTRY_HANDLER
};


// MacroAssembler implements a collection of frequently used macros.
class MacroAssembler: public Assembler {
 public:
  MacroAssembler(void* buffer, int size);

  // ---------------------------------------------------------------------------
  // GC Support

  // Set the remembered set bit for [object+offset].
  // object is the object being stored into, value is the object being stored.
  // If offset is zero, then the scratch register contains the array index into
  // the elements array represented as a Smi.
  // All registers are clobbered by the operation.
  void RecordWrite(Register object,
                   int offset,
                   Register value,
                   Register scratch);


  // ---------------------------------------------------------------------------
  // Debugger Support

  void SaveRegistersToMemory(RegList regs);
  void RestoreRegistersFromMemory(RegList regs);
  void PushRegistersFromMemory(RegList regs);
  void PopRegistersToMemory(RegList regs);
  void CopyRegistersFromStackToMemory(Register base,
                                      Register scratch,
                                      RegList regs);


  // ---------------------------------------------------------------------------
  // Activation frames

  void EnterInternalFrame() { EnterFrame(StackFrame::INTERNAL); }
  void LeaveInternalFrame() { LeaveFrame(StackFrame::INTERNAL); }

  void EnterConstructFrame() { EnterFrame(StackFrame::CONSTRUCT); }
  void LeaveConstructFrame() { LeaveFrame(StackFrame::CONSTRUCT); }

  // Enter specific kind of exit frame; either EXIT or
  // EXIT_DEBUG. Expects the number of arguments in register eax and
  // sets up the number of arguments in register edi and the pointer
  // to the first argument in register esi.
  void EnterExitFrame(StackFrame::Type type);

  // Leave the current exit frame. Expects the return value in
  // register eax:edx (untouched) and the pointer to the first
  // argument in register esi.
  void LeaveExitFrame(StackFrame::Type type);


  // ---------------------------------------------------------------------------
  // JavaScript invokes

  // Invoke the JavaScript function code by either calling or jumping.
  void InvokeCode(const Operand& code,
                  const ParameterCount& expected,
                  const ParameterCount& actual,
                  InvokeFlag flag);

  void InvokeCode(Handle<Code> code,
                  const ParameterCount& expected,
                  const ParameterCount& actual,
                  RelocInfo::Mode rmode,
                  InvokeFlag flag);

  // Invoke the JavaScript function in the given register. Changes the
  // current context to the context in the function before invoking.
  void InvokeFunction(Register function,
                      const ParameterCount& actual,
                      InvokeFlag flag);

  // Invoke specified builtin JavaScript function. Adds an entry to
  // the unresolved list if the name does not resolve.
  void InvokeBuiltin(Builtins::JavaScript id, InvokeFlag flag);

  // Store the code object for the given builtin in the target register.
  void GetBuiltinEntry(Register target, Builtins::JavaScript id);

  // Expression support
  void Set(Register dst, const Immediate& x);
  void Set(const Operand& dst, const Immediate& x);

  // Compare object type for heap object.
  // Incoming register is heap_object and outgoing register is map.
  void CmpObjectType(Register heap_object, InstanceType type, Register map);

  // Compare instance type for map.
  void CmpInstanceType(Register map, InstanceType type);

  // FCmp is similar to integer cmp, but requires unsigned
  // jcc instructions (je, ja, jae, jb, jbe, je, and jz).
  void FCmp();

  // ---------------------------------------------------------------------------
  // Exception handling

  // Push a new try handler and link into try handler chain.
  // The return address must be pushed before calling this helper.
  // On exit, eax contains TOS (next_sp).
  void PushTryHandler(CodeLocation try_location, HandlerType type);


  // ---------------------------------------------------------------------------
  // Inline caching support

  // Generates code that verifies that the maps of objects in the
  // prototype chain of object hasn't changed since the code was
  // generated and branches to the miss label if any map has. If
  // necessary the function also generates code for security check
  // in case of global object holders. The scratch and holder
  // registers are always clobbered, but the object register is only
  // clobbered if it the same as the holder register. The function
  // returns a register containing the holder - either object_reg or
  // holder_reg.
  Register CheckMaps(JSObject* object, Register object_reg,
                     JSObject* holder, Register holder_reg,
                     Register scratch, Label* miss);

  // Generate code for checking access rights - used for security checks
  // on access to global objects across environments. The holder register
  // is left untouched, but the scratch register is clobbered.
  void CheckAccessGlobalProxy(Register holder_reg,
                              Register scratch,
                              Label* miss);


  // ---------------------------------------------------------------------------
  // Support functions.

  // Check if result is zero and op is negative.
  void NegativeZeroTest(Register result, Register op, Label* then_label);

  // Check if result is zero and op is negative in code using jump targets.
  void NegativeZeroTest(CodeGenerator* cgen,
                        Register result,
                        Register op,
                        JumpTarget* then_target);

  // Check if result is zero and any of op1 and op2 are negative.
  // Register scratch is destroyed, and it must be different from op2.
  void NegativeZeroTest(Register result, Register op1, Register op2,
                        Register scratch, Label* then_label);

  // Try to get function prototype of a function and puts the value in
  // the result register. Checks that the function really is a
  // function and jumps to the miss label if the fast checks fail. The
  // function register will be untouched; the other registers may be
  // clobbered.
  void TryGetFunctionPrototype(Register function,
                               Register result,
                               Register scratch,
                               Label* miss);

  // Generates code for reporting that an illegal operation has
  // occurred.
  void IllegalOperation(int num_arguments);

  // ---------------------------------------------------------------------------
  // Runtime calls

  // Call a code stub.
  void CallStub(CodeStub* stub);

  // Return from a code stub after popping its arguments.
  void StubReturn(int argc);

  // Call a runtime routine.
  // Eventually this should be used for all C calls.
  void CallRuntime(Runtime::Function* f, int num_arguments);

  // Convenience function: Same as above, but takes the fid instead.
  void CallRuntime(Runtime::FunctionId id, int num_arguments);

  // Tail call of a runtime routine (jump).
  // Like JumpToBuiltin, but also takes care of passing the number
  // of arguments.
  void TailCallRuntime(const ExternalReference& ext, int num_arguments);

  // Jump to the builtin routine.
  void JumpToBuiltin(const ExternalReference& ext);


  // ---------------------------------------------------------------------------
  // Utilities

  void Ret();

  struct Unresolved {
    int pc;
    uint32_t flags;  // see Bootstrapper::FixupFlags decoders/encoders.
    const char* name;
  };
  List<Unresolved>* unresolved() { return &unresolved_; }

  Handle<Object> CodeObject() { return code_object_; }


  // ---------------------------------------------------------------------------
  // StatsCounter support

  void SetCounter(StatsCounter* counter, int value);
  void IncrementCounter(StatsCounter* counter, int value);
  void DecrementCounter(StatsCounter* counter, int value);


  // ---------------------------------------------------------------------------
  // Debugging

  // Calls Abort(msg) if the condition cc is not satisfied.
  // Use --debug_code to enable.
  void Assert(Condition cc, const char* msg);

  // Like Assert(), but always enabled.
  void Check(Condition cc, const char* msg);

  // Print a message to stdout and abort execution.
  void Abort(const char* msg);

  // Verify restrictions about code generated in stubs.
  void set_generating_stub(bool value) { generating_stub_ = value; }
  bool generating_stub() { return generating_stub_; }
  void set_allow_stub_calls(bool value) { allow_stub_calls_ = value; }
  bool allow_stub_calls() { return allow_stub_calls_; }

 private:
  List<Unresolved> unresolved_;
  bool generating_stub_;
  bool allow_stub_calls_;
  Handle<Object> code_object_;  // This handle will be patched with the code
                                // code object on installation.

  // Helper functions for generating invokes.
  void InvokePrologue(const ParameterCount& expected,
                      const ParameterCount& actual,
                      Handle<Code> code_constant,
                      const Operand& code_operand,
                      Label* done,
                      InvokeFlag flag);

  // Get the code for the given builtin. Returns if able to resolve
  // the function in the 'resolved' flag.
  Handle<Code> ResolveBuiltin(Builtins::JavaScript id, bool* resolved);

  // Activation support.
  void EnterFrame(StackFrame::Type type);
  void LeaveFrame(StackFrame::Type type);
};


// The code patcher is used to patch (typically) small parts of code e.g. for
// debugging and other types of instrumentation. When using the code patcher
// the exact number of bytes specified must be emitted. Is not legal to emit
// relocation information. If any of these constraints are violated it causes
// an assertion.
class CodePatcher {
 public:
  CodePatcher(byte* address, int size);
  virtual ~CodePatcher();

  // Macro assembler to emit code.
  MacroAssembler* masm() { return &masm_; }

 private:
  byte* address_;  // The address of the code being patched.
  int size_;  // Number of bytes of the expected patch size.
  MacroAssembler masm_;  // Macro assembler used to generate the code.
};


// -----------------------------------------------------------------------------
// Static helper functions.

// Generate an Operand for loading a field from an object.
static inline Operand FieldOperand(Register object, int offset) {
  return Operand(object, offset - kHeapObjectTag);
}


// Generate an Operand for loading an indexed field from an object.
static inline Operand FieldOperand(Register object,
                                   Register index,
                                   ScaleFactor scale,
                                   int offset) {
  return Operand(object, index, scale, offset - kHeapObjectTag);
}

} }  // namespace v8::internal

#endif  // V8_MACRO_ASSEMBLER_IA32_H_