macro-assembler-arm.cc.svn-base

Google浏览器V8内核代码

}


void MacroAssembler::InvokeCode(Register code,
                                const ParameterCount& expected,
                                const ParameterCount& actual,
                                InvokeFlag flag) {
  Label done;

  InvokePrologue(expected, actual, Handle<Code>::null(), code, &done, flag);
  if (flag == CALL_FUNCTION) {
    Call(code);
  } else {
    ASSERT(flag == JUMP_FUNCTION);
    Jump(code);
  }

  // Continue here if InvokePrologue does handle the invocation due to
  // mismatched parameter counts.
  bind(&done);
}


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

  InvokePrologue(expected, actual, code, no_reg, &done, flag);
  if (flag == CALL_FUNCTION) {
    Call(code, rmode);
  } else {
    Jump(code, rmode);
  }

  // Continue here if InvokePrologue does handle the invocation due to
  // mismatched parameter counts.
  bind(&done);
}


void MacroAssembler::InvokeFunction(Register fun,
                                    const ParameterCount& actual,
                                    InvokeFlag flag) {
  // Contract with called JS functions requires that function is passed in r1.
  ASSERT(fun.is(r1));

  Register expected_reg = r2;
  Register code_reg = r3;

  ldr(code_reg, FieldMemOperand(r1, JSFunction::kSharedFunctionInfoOffset));
  ldr(cp, FieldMemOperand(r1, JSFunction::kContextOffset));
  ldr(expected_reg,
      FieldMemOperand(code_reg,
                      SharedFunctionInfo::kFormalParameterCountOffset));
  ldr(code_reg,
      MemOperand(code_reg, SharedFunctionInfo::kCodeOffset - kHeapObjectTag));
  add(code_reg, code_reg, Operand(Code::kHeaderSize - kHeapObjectTag));

  ParameterCount expected(expected_reg);
  InvokeCode(code_reg, expected, actual, flag);
}


void MacroAssembler::SaveRegistersToMemory(RegList regs) {
  ASSERT((regs & ~kJSCallerSaved) == 0);
  // Copy the content of registers to memory location.
  for (int i = 0; i < kNumJSCallerSaved; i++) {
    int r = JSCallerSavedCode(i);
    if ((regs & (1 << r)) != 0) {
      Register reg = { r };
      mov(ip, Operand(ExternalReference(Debug_Address::Register(i))));
      str(reg, MemOperand(ip));
    }
  }
}


void MacroAssembler::RestoreRegistersFromMemory(RegList regs) {
  ASSERT((regs & ~kJSCallerSaved) == 0);
  // Copy the content of memory location to registers.
  for (int i = kNumJSCallerSaved; --i >= 0;) {
    int r = JSCallerSavedCode(i);
    if ((regs & (1 << r)) != 0) {
      Register reg = { r };
      mov(ip, Operand(ExternalReference(Debug_Address::Register(i))));
      ldr(reg, MemOperand(ip));
    }
  }
}


void MacroAssembler::CopyRegistersFromMemoryToStack(Register base,
                                                    RegList regs) {
  ASSERT((regs & ~kJSCallerSaved) == 0);
  // Copy the content of the memory location to the stack and adjust base.
  for (int i = kNumJSCallerSaved; --i >= 0;) {
    int r = JSCallerSavedCode(i);
    if ((regs & (1 << r)) != 0) {
      mov(ip, Operand(ExternalReference(Debug_Address::Register(i))));
      ldr(ip, MemOperand(ip));
      str(ip, MemOperand(base, 4, NegPreIndex));
    }
  }
}


void MacroAssembler::CopyRegistersFromStackToMemory(Register base,
                                                    Register scratch,
                                                    RegList regs) {
  ASSERT((regs & ~kJSCallerSaved) == 0);
  // Copy the content of the stack to the memory location and adjust base.
  for (int i = 0; i < kNumJSCallerSaved; i++) {
    int r = JSCallerSavedCode(i);
    if ((regs & (1 << r)) != 0) {
      mov(ip, Operand(ExternalReference(Debug_Address::Register(i))));
      ldr(scratch, MemOperand(base, 4, PostIndex));
      str(scratch, MemOperand(ip));
    }
  }
}


void MacroAssembler::PushTryHandler(CodeLocation try_location,
                                    HandlerType type) {
  ASSERT(StackHandlerConstants::kSize == 6 * kPointerSize);  // adjust this code
  // The pc (return address) is passed in register lr.
  if (try_location == IN_JAVASCRIPT) {
    stm(db_w, sp, pp.bit() | fp.bit() | lr.bit());
    if (type == TRY_CATCH_HANDLER) {
      mov(r3, Operand(StackHandler::TRY_CATCH));
    } else {
      mov(r3, Operand(StackHandler::TRY_FINALLY));
    }
    push(r3);  // state
    mov(r3, Operand(ExternalReference(Top::k_handler_address)));
    ldr(r1, MemOperand(r3));
    push(r1);  // next sp
    str(sp, MemOperand(r3));  // chain handler
    mov(r0, Operand(Smi::FromInt(StackHandler::kCodeNotPresent)));  // new TOS
    push(r0);
  } else {
    // Must preserve r0-r4, r5-r7 are available.
    ASSERT(try_location == IN_JS_ENTRY);
    // The parameter pointer is meaningless here and fp does not point to a JS
    // frame. So we save NULL for both pp and fp. We expect the code throwing an
    // exception to check fp before dereferencing it to restore the context.
    mov(pp, Operand(0));  // set pp to NULL
    mov(ip, Operand(0));  // to save a NULL fp
    stm(db_w, sp, pp.bit() | ip.bit() | lr.bit());
    mov(r6, Operand(StackHandler::ENTRY));
    push(r6);  // state
    mov(r7, Operand(ExternalReference(Top::k_handler_address)));
    ldr(r6, MemOperand(r7));
    push(r6);  // next sp
    str(sp, MemOperand(r7));  // chain handler
    mov(r5, Operand(Smi::FromInt(StackHandler::kCodeNotPresent)));  // new TOS
    push(r5);  // flush TOS
  }
}


Register MacroAssembler::CheckMaps(JSObject* object, Register object_reg,
                                   JSObject* holder, Register holder_reg,
                                   Register scratch,
                                   Label* miss) {
  // Make sure there's no overlap between scratch and the other
  // registers.
  ASSERT(!scratch.is(object_reg) && !scratch.is(holder_reg));

  // Keep track of the current object in register reg.
  Register reg = object_reg;
  int depth = 1;

  // Check the maps in the prototype chain.
  // Traverse the prototype chain from the object and do map checks.
  while (object != holder) {
    depth++;

    // Only global objects and objects that do not require access
    // checks are allowed in stubs.
    ASSERT(object->IsJSGlobalObject() || !object->IsAccessCheckNeeded());

    // Get the map of the current object.
    ldr(scratch, FieldMemOperand(reg, HeapObject::kMapOffset));
    cmp(scratch, Operand(Handle<Map>(object->map())));

    // Branch on the result of the map check.
    b(ne, miss);

    // Check access rights to the global object.  This has to happen
    // after the map check so that we know that the object is
    // actually a global object.
    if (object->IsJSGlobalObject()) {
      CheckAccessGlobal(reg, scratch, miss);
      // Restore scratch register to be the map of the object.  In the
      // new space case below, we load the prototype from the map in
      // the scratch register.
      ldr(scratch, FieldMemOperand(reg, HeapObject::kMapOffset));
    }

    reg = holder_reg;  // from now the object is in holder_reg
    JSObject* prototype = JSObject::cast(object->GetPrototype());
    if (Heap::InNewSpace(prototype)) {
      // The prototype is in new space; we cannot store a reference
      // to it in the code. Load it from the map.
      ldr(reg, FieldMemOperand(scratch, Map::kPrototypeOffset));
    } else {
      // The prototype is in old space; load it directly.
      mov(reg, Operand(Handle<JSObject>(prototype)));
    }

    // Go to the next object in the prototype chain.
    object = prototype;
  }

  // Check the holder map.
  ldr(scratch, FieldMemOperand(reg, HeapObject::kMapOffset));
  cmp(scratch, Operand(Handle<Map>(object->map())));
  b(ne, miss);

  // Log the check depth.
  LOG(IntEvent("check-maps-depth", depth));

  // Perform security check for access to the global object and return
  // the holder register.
  ASSERT(object == holder);
  ASSERT(object->IsJSGlobalObject() || !object->IsAccessCheckNeeded());
  if (object->IsJSGlobalObject()) {
    CheckAccessGlobal(reg, scratch, miss);
  }
  return reg;
}


void MacroAssembler::CheckAccessGlobal(Register holder_reg,
                                       Register scratch,
                                       Label* miss) {
  ASSERT(!holder_reg.is(scratch));

  // Load the security context.
  mov(scratch, Operand(Top::security_context_address()));
  ldr(scratch, MemOperand(scratch));
  // In debug mode, make sure the security context is set.
  if (kDebug) {
    cmp(scratch, Operand(0));
    Check(ne, "we should not have an empty security context");
  }

  // Load the global object of the security context.
  int offset = Context::kHeaderSize + Context::GLOBAL_INDEX * kPointerSize;
  ldr(scratch, FieldMemOperand(scratch, offset));
  // Check that the security token in the calling global object is
  // compatible with the security token in the receiving global
  // object.
  ldr(scratch, FieldMemOperand(scratch, JSGlobalObject::kSecurityTokenOffset));
  ldr(ip, FieldMemOperand(holder_reg, JSGlobalObject::kSecurityTokenOffset));
  cmp(scratch, Operand(ip));
  b(ne, miss);
}


void MacroAssembler::CallStub(CodeStub* stub) {
  ASSERT(allow_stub_calls());  // stub calls are not allowed in some stubs
  Call(stub->GetCode(), RelocInfo::CODE_TARGET);
}


void MacroAssembler::StubReturn(int argc) {
  ASSERT(argc >= 1 && generating_stub());
  if (argc > 1)
    add(sp, sp, Operand((argc - 1) * kPointerSize));
  Ret();
}


void MacroAssembler::CallRuntime(Runtime::Function* f, int num_arguments) {
  // All parameters are on the stack.  r0 has the return value after call.

  // Either the expected number of arguments is unknown, or the actual
  // number of arguments match the expectation.
  ASSERT(f->nargs < 0 || f->nargs == num_arguments);

  Runtime::FunctionId function_id =
      static_cast<Runtime::FunctionId>(f->stub_id);
  RuntimeStub stub(function_id, num_arguments);
  CallStub(&stub);
}


void MacroAssembler::CallRuntime(Runtime::FunctionId fid, int num_arguments) {
  CallRuntime(Runtime::FunctionForId(fid), num_arguments);
}


void MacroAssembler::TailCallRuntime(const ExternalReference& ext,
                                     int num_arguments) {
  // TODO(1236192): Most runtime routines don't need the number of
  // arguments passed in because it is constant. At some point we
  // should remove this need and make the runtime routine entry code
  // smarter.
  mov(r0, Operand(num_arguments));
  JumpToBuiltin(ext);
}


void MacroAssembler::JumpToBuiltin(const ExternalReference& builtin) {
#if defined(__thumb__)
  // Thumb mode builtin.
  ASSERT((reinterpret_cast<intptr_t>(builtin.address()) & 1) == 1);
#endif
  mov(r1, Operand(builtin));
  CEntryStub stub;
  Jump(stub.GetCode(), RelocInfo::CODE_TARGET);
}


Handle<Code> MacroAssembler::ResolveBuiltin(Builtins::JavaScript id,
                                            bool* resolved) {
  // Contract with compiled functions is that the function is passed in r1.
  int builtins_offset =
      JSBuiltinsObject::kJSBuiltinsOffset + (id * kPointerSize);
  ldr(r1, MemOperand(cp, Context::SlotOffset(Context::GLOBAL_INDEX)));
  ldr(r1, FieldMemOperand(r1, GlobalObject::kBuiltinsOffset));
  ldr(r1, FieldMemOperand(r1, builtins_offset));

  return Builtins::GetCode(id, resolved);
}


void MacroAssembler::InvokeBuiltin(Builtins::JavaScript id,
                                   InvokeJSFlags flags) {
  bool resolved;
  Handle<Code> code = ResolveBuiltin(id, &resolved);

  if (flags == CALL_JS) {
    Call(code, RelocInfo::CODE_TARGET);
  } else {
    ASSERT(flags == JUMP_JS);
    Jump(code, RelocInfo::CODE_TARGET);
  }

  if (!resolved) {
    const char* name = Builtins::GetName(id);
    int argc = Builtins::GetArgumentsCount(id);
    uint32_t flags =
        Bootstrapper::FixupFlagsArgumentsCount::encode(argc) |
        Bootstrapper::FixupFlagsIsPCRelative::encode(true);
    Unresolved entry = { pc_offset() - sizeof(Instr), flags, name };
    unresolved_.Add(entry);
  }
}


void MacroAssembler::GetBuiltinEntry(Register target, Builtins::JavaScript id) {
  bool resolved;
  Handle<Code> code = ResolveBuiltin(id, &resolved);

  mov(target, Operand(code));
  if (!resolved) {
    const char* name = Builtins::GetName(id);
    int argc = Builtins::GetArgumentsCount(id);
    uint32_t flags =
        Bootstrapper::FixupFlagsArgumentsCount::encode(argc) |
        Bootstrapper::FixupFlagsIsPCRelative::encode(true);
    Unresolved entry = { pc_offset() - sizeof(Instr), flags, name };
    unresolved_.Add(entry);
  }
}


void MacroAssembler::Assert(Condition cc, const char* msg) {
  if (FLAG_debug_code)
    Check(cc, msg);
}


void MacroAssembler::Check(Condition cc, const char* msg) {
  Label L;
  b(cc, &L);
  Abort(msg);
  // will not return here
  bind(&L);
}


void MacroAssembler::Abort(const char* msg) {
  // We want to pass the msg string like a smi to avoid GC
  // problems, however msg is not guaranteed to be aligned
  // properly. Instead, we pass an aligned pointer that is
  // a proper v8 smi, but also pass the aligment difference
  // from the real pointer as a smi.
  intptr_t p1 = reinterpret_cast<intptr_t>(msg);
  intptr_t p0 = (p1 & ~kSmiTagMask) + kSmiTag;
  ASSERT(reinterpret_cast<Object*>(p0)->IsSmi());
#ifdef DEBUG
  if (msg != NULL) {
    RecordComment("Abort message: ");
    RecordComment(msg);
  }
#endif
  mov(r0, Operand(p0));
  push(r0);
  mov(r0, Operand(Smi::FromInt(p1 - p0)));
  push(r0);
  CallRuntime(Runtime::kAbort, 2);
  // will not return here
}

} }  // namespace v8::internal