Thanks Gabor.
I actually implemented adding my code injection before each
OpCodes.Return instance in the MethodDefinition.Body.Instructions
list.
I did need to inject the code differently depending if the method was
returning a value or void so that it kept returning it correctly.
However, I'm now facing an issue with if statements that are on the
end of a method. For instance, imagine the following method:
public void Foo()
{
this.DoSomething();
if(myProperty.IsTrue)
{
this.DoSomethingElse();
}
}
If I use the last OpCodes.Ret, it actually injects my code in the if
statement like so:
public void Foo()
{
this.DoSomething();
if(myProperty.IsTrue)
{
this.DoSomethingElse();
this.MyInjectedCodeMethod();
}
}
instead of putting it at the real end of the method. Do I have no
other choice than parsing the method and see if I have a brfalse or
brtrue that points to one of my ret addresses in the IL instructions?
And if that is the case, is there any other similar case that I should
take care of?
Thanks
On 7 juil, 22:34, Gábor Kozár <[email protected]> wrote:
> It means that the exact same values will be on the stack after your custom
> injected code, than before. Essentially means that your injected code does
> not push any value to the stack it does not pop later, and also it does not
> pop any values from the stack that it did not push (unless you save the
> value to, for example, a local variable first and then load it back later).
>
> My project had a similar problem, when I was writing a method using
> Mono.Cecil to inline (specific) method calls. I solved it by basically
> injecting my custom code before all 'ret' instructions. (It's a bit more
> complicated than that, because most of the 'ret' instructions are removed
> during inlining, but you get the point.)
>
> 2011/7/7 Indiefreaks.com <[email protected]>
>
>
>
> > What do you mean stabilizing the stack?
>
> > On 7 juil, 14:37, Alex <[email protected]> wrote:
> > > Hi,
>
> > > >Well, I tried that method but I get way too many return operations in
>
> > > some situations like when a switch operation occurs in the method.
> > > Moreover, if I fear that simply injecting my code before the
> > > OpCodes.Ret instruction wouldn't work neither in some cases like when
> > > a value is returned by the method.
>
> > > I don't think that's a problem as long as you correctly stabilize the
> > stack.
>
> > > Regards,
> > > Alex
>
> > > On Thu, Jul 7, 2011 at 2:30 PM, Indiefreaks.com
>
> > > <[email protected]> wrote:
> > > > Well, I tried that method but I get way too many return operations in
> > > > some situations like when a switch operation occurs in the method.
> > > > Moreover, if I fear that simply injecting my code before the
> > > > OpCodes.Ret instruction wouldn't work neither in some cases like when
> > > > a value is returned by the method.
>
> > > > I may also go down the route of cloning the current method and adding
> > > > it (with a different name) to the current class and then clear the
> > > > current method instructions and surround a call to the cached method
> > > > by my profiling code making sure that I catch the returned value if
> > > > different from "System.Void" to return it back once the original
> > > > method ends...
>
> > > > On 7 juil, 13:44, Alex <[email protected]> wrote:
> > > >> Hi,
>
> > > >> I think what you propose is the best way to achieve this. I'm not sure
> > > >> if 'ret' is the only opcode that can leave a method normally, though.
>
> > > >> Regards,
> > > >> Alex
>
> > > >> On Thu, Jul 7, 2011 at 11:47 AM, Indiefreaks.com
>
> > > >> <[email protected]> wrote:
> > > >> > Hi,
>
> > > >> > In my current Xna game profiler tool (learn more athttp://
> > indiefreaks.com),
> > > >> > I'm wrapping each method that should be profiled with my profiling
> > > >> > code.
>
> > > >> > Right now, in order to do so, I'm getting the first instruction from
> > > >> > the MethodDefinition Body as well as the last one and inject my code
> > > >> > before them.
>
> > > >> > It works perfectly fine on most cases except when a control flow
> > > >> > operation code is set in the body.
>
> > > >> > My profiling code that is injected before the actual method is
> > invoked
> > > >> > works fine but because of the previous statement, the code I inject
> > at
> > > >> > what I would consider the end of the method never gets called or
> > gets
> > > >> > called inside an if or switch statement which crashes the resulting
> > > >> > assembly.
>
> > > >> > From what I understand, if I have such control flow operations, the
> > > >> > last instruction in a method body may not be the end of the current
> > > >> > Method.
>
> > > >> > I'm now considering parsing the whole method instructions and look
> > for
> > > >> > each OpCodes.Ret instance to add my custom code there but I wondered
> > > >> > if there was a better solution to find the end of a method or hook
> > to
> > > >> > it.
>
> > > >> > Thanks
>
> > > >> > --
> > > >> > --
> > > >> > mono-cecil- Masquer le texte des messages précédents -
>
> > > >> - Afficher le texte des messages précédents -
>
> > > > --
> > > > --
> > > > mono-cecil- Masquer le texte des messages précédents -
>
> > > - Afficher le texte des messages précédents -
>
> > --
> > --
> > mono-cecil- Masquer le texte des messages précédents -
>
> - Afficher le texte des messages précédents -
--
--
mono-cecil
