On 06/04/2024 14:53, Richard Biener wrote: > On Fri, Apr 5, 2024 at 3:44 PM Pierrick Philippe > wrote: >> On 05/04/2024 14:46, Richard Biener wrote: >> >> On Fri, Apr 5, 2024 at 1:59 PM Pierrick Philippe >> wrote: >> >> Hi all, >> >> I do have a question regarding ssa_name and result_decl. >> >> For example on the following gimple function: >> >> int f () >> { >> int x; >> int D.2747; >> int _2; >> >> : >> x_1 = 42; >> _2 = x_1; >> >> : >> : >> return _2; >> >> } >> >> On the above example, using the macro SSA_NAME_VAR() on _2 does not >> yield anything usable. >> Neither to call ssa_default_def() on the result of the result_decl >> obtain through macro DECL_RESULT(). >> >> Is there a way to get the ssa_name corresponding to the result_decl of a >> function obtained through the use of macro DECL_RESULT() on a fn_decl? >> And/or the other way around? I.e., from the returned ssa_name of a >> function to the result_decl of that function? >> >> I totally might be missing something here, but I cannot figure out what. >> >> DECL_RESULT isn't always used (as in your example). Not all SSA names >> have corresponding declarations, we have "anonymous" SSA names which >> have a NULL_TREE SSA_NAME_VAR (such as the _2 in your example). >> >> I see, that makes so much more sense to me now. >> >> What do you try to find in the end? If you want to find all returns you can >> walk predecessors of EXIT_BLOCK and look at their last stmt whether they >> are greturn statements. >> >> I am implementing a state_machine within the analyzer, and I am trying to understand where would be the best place to propagate the state of the return value. >> I intuitively thought it would be best to do so in the state_machine::on_pop_frame() method, which is called by the analyzer between the two frames of the caller and the callee. What I do have access to is the struct function of the callee/caller, the gcall instruction in the caller and the callee have been processed by my analysis. > It might make sense to record the analysis of the return value in > meta-data that the analyzer keeps and access it that way. > Other than that you'd have to do it the way I said with finding the > greturn stmts again and look at what is returned there. That is what I had in mind, thanks for answering me. I do have another question though, how do you obtain the decl_context of such an ssa_name? The DECL_CONTEXT macro is failing during the tree check and I ha ve no idea how to know where a given ssa_name is declared without accessing its inner var (through SSA_NAME_VAR). And this operation is failing on _i ssa_name trees. >> And to illustrate, here I do have the _2 ssa_name and its state which I know in that case should be propagate to the lhs of the caller gcall instruction. >> >> Again I might be taking this in a wrong way. >> >> Richard. >> >> Thanks for your time, >> >> Pierrick