Re: [Gcc4cli-devel] Mono.Cecil: Fixing wrong prototypes at link time

[Erven R. <erv...@in...>]

Le 06/05/2011 18:26, David Yuste a écrit :
> Hi,
>
> I developed a small method to fix prototypes at link time (thus, it is implemented in Mono.Cecil).
>
> Basically, it compares the signature of each function involved in a *direct* call with the signature of the corresponding function definition. If they differ (right now I only care about the return value), it updates the signature in the call statement. In addition, if the call signature was "not void" typed, while the actual function is "void" typed, the next instruction is checked. If this instruction is "pop", it is deleted (thus we avoid an incorrect stack error).
>
> As limitation, it doesn't apply to indirect calls (since we don't know the callee function).
>
> Since I don't have write access to the Mono.Cecil repository (and also we work on a version, why?),


Just to make sure we know what we work on.
It could be interesting to see if the latest version works for us (ie no change 
in API, etc.) It could actually also be that it fixes the problem you discovered 
with the range of branch instructions.

--
Erven.


  I just attach the patch. I'm still experiencing with it, but it worked 
properly in all my tests.
>
> Finally, just an example of the problem and the solution (introduced at link time):
>
> *** Source code
>    file1.c
>    ---
>    void foo (char ** argv) {
>    }
>    ---
>
>    file2.c
>    ---
>    int main (int argc, char ** argv) {
>      foo (argv);  ->  guessed as 'int foo (char**)'
>    }
>    ---
>
> *** After cil32
>    file1.cil32
>    ---
>    .method public static void 'foo' (int8 * * 'argv') cil managed
>    {
>     ...
>    }
>    ---
>
>    file2.cil32
>    ---
>    .method public static int32 'main' (int32 'argc', int8 * * 'argv') cil managed {
>      ...
>      call    int32 [ExternalAssembly]ExternalAssembly::'no_prototype' (native int)
>      pop
>      ldc.i4  0
>      ...
>    }
>    ---
>
> *** After link (with our pass)
>    .method public static
>      default int32 main (int32 argc, int8** argv)
>      cil managed
>    {
>      // Method begins at RVA 0x2084
>      // Code size 9 (0x9)
>      .maxstack 8
>      IL_0000:   ldarg.1
>      IL_0001:   conv.i
>      IL_0002:   call void test::foo(int8**)   //Fixed return value
>      IL_0007:   ldc.i4.0  //Pop removed, the stack is correct
>      IL_0008:   ret
>    } // end of method test::main
>
>
> David