我能消除额外的Unicode字符串调用吗(Delphi)

我使用的是Delphi2009,在我的程序中,我一直在努力优化我所有的Delphi代码的速度和内存使用,特别是我的Unicode字符串处理。

我有以下声明:

    Result := Result + GetFirstLastName(IndiID, 1);

当我调试该行时,从GetFirstLastName函数返回时,它会跟踪到系统单元中的例程UStrArrayClr:

procedure _UStrArrayClr(var StrArray; Count: Integer);
asm
        JMP     _LStrArrayClr
end;

这将调用\u LStrArrayClr:

procedure       _LStrArrayClr(var StrArray; cnt: longint);
{$IFDEF PUREPASCAL}
var
  P: Pointer;
begin
  P := @StrArray;
  while cnt > 0 do
  begin
    _LStrClr(P^);
    Dec(cnt);
    Inc(Integer(P), sizeof(Pointer));
  end;
end;
{$ELSE}
asm
        { ->    EAX pointer to str      }
        {       EDX cnt         }

        PUSH    EBX
        PUSH    ESI
        MOV     EBX,EAX
        MOV     ESI,EDX

@@loop:
        MOV     EDX,[EBX]                       { fetch str                     }
        TEST    EDX,EDX                         { if nil, nothing to do         }
        JE      @@doneEntry
        MOV     dword ptr [EBX],0               { clear str                     }
        MOV     ECX,[EDX-skew].StrRec.refCnt    { fetch refCnt                  }
        DEC     ECX                             { if < 0: literal str           }
        JL      @@doneEntry
   LOCK DEC     [EDX-skew].StrRec.refCnt        { threadsafe dec refCount       }
        JNE     @@doneEntry
        LEA     EAX,[EDX-skew].StrRec.codePage  { if refCnt now zero, deallocate}
        CALL    _FreeMem
@@doneEntry:
        ADD     EBX,4
        DEC     ESI
        JNE     @@loop

        POP     ESI
        POP     EBX
end;
{$ENDIF}

并为每个字符在循环中运行一次,从循环中退出时,它将调用\u UStrCat:

procedure _UStrCat(var Dest: UnicodeString; const Source: UnicodeString);
asm
        { ->    EAX     pointer to dest }
        {       EDX source              }

        TEST    EDX,EDX       // Source empty, nop.
        JE      @@exit

        MOV     ECX,[EAX]     // ECX := Dest
        TEST    ECX,ECX       // Nil source => assignment
        JE      _UStrAsg

        PUSH    EBX
        PUSH    ESI
        PUSH    EDI
        MOV     EBX,EAX         // EBX := @Dest
        MOV     ESI,EDX         // ESI := Source
        CMP     ESI,ECX
        JE      @@appendSelf

        CMP     [ECX-skew].StrRec.elemSize,2
        JE      @@destIsUnicode
        CALL    _EnsureUnicodeString
        MOV     EDI,EAX
        MOV     ECX,EAX

@@destIsUnicode:
        PUSH    0
        CMP     [ESI-skew].StrRec.elemSize,2
        JE      @@sourceIsUnicode

        MOV     EDI,ECX
        MOV     EAX,ESI
        MOV     [ESP],ESI
        CALL    _UStrAddRef
        MOV     EAX,ESP
        CALL    _EnsureUnicodeString
        MOV     ESI,[ESP]
        MOV     ECX,EDI

@@sourceIsUnicode:
        MOV     EDI,[ECX-skew].StrRec.length  // EDI := Length(Dest)
        MOV     EDX,[ESI-skew].StrRec.length  // EDX := Length(Source)
        ADD     EDX,EDI         // EDX := (Length(Source) + Length(Dest)) * 2
        TEST    EDX,$C0000000
        JNZ     @@lengthOverflow

        MOV     EAX,EBX
        CALL    _UStrSetLength  // Set length of Dest
        MOV     EAX,ESI         // EAX := Source
        MOV     ECX,[ESI-skew].StrRec.length // ECX := Length(Source)

@@noTemp:
        MOV     EDX,[EBX]       // EDX := Dest
        SHL     EDI,1           // EDI to bytes (Length(Dest) * 2)
        ADD     EDX,EDI         // Offset EDX for destination of move
        SHL     ECX,1           // convert Length(Source) to bytes
        CALL    Move            // Move(Source, Dest + Length(Dest)*2, Length(Source)*2)
        MOV     EAX,ESP         // Need to clear out the temp we may have created above
        MOV     EDX,[EAX]
        TEST    EDX,EDX
        JE      @@tempEmpty

        CALL    _LStrClr

@@tempEmpty:
        POP     EAX
        POP     EDI
        POP     ESI
        POP     EBX
        RET

@@appendSelf:
        CMP     [ECX-skew].StrRec.elemSize,2
        JE      @@selfIsUnicode
        MOV     EAX,EBX
        XOR     EDX,EDX
        CALL    _EnsureUnicodeString
        MOV     ECX,EAX
        MOV     EAX,EBX

@@selfIsUnicode:
        MOV     EDI,[ECX-skew].StrRec.length
        MOV     EDX,EDI
        SHL     EDX,1
        TEST    EDX,$C0000000
        JNZ     @@lengthOverflow
        CALL    _UStrSetLength
        MOV     EAX,[EBX]
        MOV     ECX,EDI
        PUSH    0
        JMP     @@noTemp

@@lengthOverflow:
        JMP     _IntOver

@@exit:
end;

我的“Result”是一个字符串,因此是Unicode。我的GetFirstLastName返回一个Unicode字符串。不需要转换字符集。

他们在做什么?有必要吗?如果它们不是必需的,如何防止编译器调用这些例程?