> Hi!
>
> The following testcase ICEs on x86_64-linux with -m32. The problem is
> we create an artificial thunk and because of -fPIC, ia32 and thunk
> destination which doesn't bind locally can't use a mi thunk.
> The ICE is because during expansion to RTL we see SSA_NAME for a PARM_DECL,
> but the PARM_DECL doesn't have DECL_CONTEXT of the current function.
> This is because duplicate_thunk_for_node creates a new DECL_ARGUMENTS chain
> only if some arguments need modification.
>
> The following patch fixes it by copying the DECL_ARGUMENTS list even if
> the arguments can stay as is, to update DECL_CONTEXT on them. While for
> mi thunks it doesn't really matter because we don't use those arguments
> in any way, for other thunks it is important.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
> 2023-02-23 Jakub Jelinek <ja...@redhat.com>
>
> PR middle-end/108854
> * cgraphclones.cc (duplicate_thunk_for_node): If no parameter
> changes are needed, copy at least DECL_ARGUMENTS PARM_DECL
> nodes and adjust their DECL_CONTEXT.
>
> * g++.dg/opt/pr108854.C: New test.
>
> --- gcc/cgraphclones.cc.jj 2023-02-22 20:50:27.417519830 +0100
> +++ gcc/cgraphclones.cc 2023-02-23 17:12:59.875133883 +0100
> @@ -218,7 +218,17 @@ duplicate_thunk_for_node (cgraph_node *t
> body_adj.modify_formal_parameters ();
> }
> else
> - new_decl = copy_node (thunk->decl);
> + {
> + new_decl = copy_node (thunk->decl);
> + for (tree *arg = &DECL_ARGUMENTS (new_decl);
> + *arg; arg = &DECL_CHAIN (*arg))
> + {
> + tree next = DECL_CHAIN (*arg);
> + *arg = copy_node (*arg);
> + DECL_CONTEXT (*arg) = new_decl;
> + DECL_CHAIN (*arg) = next;
This makes sense to me. I wonder if we don't want to update abstract
origin too like we do in tree-inline?
Maybe it is unecessary since we don't do debug info for thunks....
Jan
