查看使用 WinDbg/SOS 何时对方法进行 JIT 编译表明,静态方法在调用之前不会进行编译。
考虑下面的类:
class SomeType
{
[MethodImpl(MethodImplOptions.NoInlining)]
public void InstanceMethod()
{
Console.WriteLine("instance");
}
[MethodImpl(MethodImplOptions.NoInlining)]
public static void TypeMethod()
{
Console.WriteLine("type");
}
}
我使用 NoInlined 选项来防止编译器在发布版本中内联这些方法。
如果我运行一个如下所示的小应用程序并附加 WinDbg,我可以观察方法何时进行 JIT 编译。
var st = new SomeType();
Console.WriteLine("attach");
Console.ReadLine();
Console.WriteLine("calling methods");
st.InstanceMethod();
SomeType.TypeMethod();
Console.ReadLine();
附上方法表SomeType
看起来像这样:
0:004> !dumpmt -md 0041387c
EEClass: 004114d4
Module: 00412e94
Name: ConsoleApplication2.SomeType
mdToken: 02000007
File: c:\temp\ConsoleApplication1\ConsoleApplication1\bin\Release\ConsoleApplication1.exe
BaseSize: 0xc
ComponentSize: 0x0
Slots in VTable: 7
Number of IFaces in IFaceMap: 0
--------------------------------------
MethodDesc Table
Entry MethodDe JIT Name
6d374960 6d076728 PreJIT System.Object.ToString()
6d368790 6d076730 PreJIT System.Object.Equals(System.Object)
6d368360 6d076750 PreJIT System.Object.GetHashCode()
6d3616f0 6d076764 PreJIT System.Object.Finalize()
0041c035 00413874 NONE ConsoleApplication2.SomeType..ctor()
0041c02d 0041385c NONE ConsoleApplication2.SomeType.InstanceMethod()
0041c031 00413868 NONE ConsoleApplication2.SomeType.TypeMethod()
显式调用这些方法后,它看起来像这样:
0:007> !dumpmt -md 0041387c
EEClass: 004114d4
Module: 00412e94
Name: ConsoleApplication2.SomeType
mdToken: 02000007
File: c:\temp\ConsoleApplication1\ConsoleApplication1\bin\Release\ConsoleApplication1.exe
BaseSize: 0xc
ComponentSize: 0x0
Slots in VTable: 7
Number of IFaces in IFaceMap: 0
--------------------------------------
MethodDesc Table
Entry MethodDe JIT Name
6d374960 6d076728 PreJIT System.Object.ToString()
6d368790 6d076730 PreJIT System.Object.Equals(System.Object)
6d368360 6d076750 PreJIT System.Object.GetHashCode()
6d3616f0 6d076764 PreJIT System.Object.Finalize()
0041c035 00413874 NONE ConsoleApplication2.SomeType..ctor()
004700e0 0041385c JIT ConsoleApplication2.SomeType.InstanceMethod()
00470110 00413868 JIT ConsoleApplication2.SomeType.TypeMethod()
IE。这些方法在实际调用之前不会进行 JIT 编译。
(根据记录,这是在 .NET 4.5 上完成的)