In that case I shall create appropriate issues for the mentioned compilers in order to discuss the matter with them.
I think I have found another issue with clang. In some cases it does not generate middle parameters: namely, it skipped the 2nd one yet included the 3rd one. It believe it does not match the standard (p91 line 6-7): "Call site parameter entries occur in the same order as the corresponding parameters in the source.", does it? On Jun 14, 2024, 15:11 +0300, Robinson, Paul <paul.robin...@sony.com>, wrote: > I believe this is an issue with the implementations, although it is a bit odd > that both gcc and clang behave the same way. There should be a > DW_TAG_call_site_parameter for each parameter. DW_AT_location should describe > the stack slot where the parameter is passed. It should not be a problem for > the compiler to do that, the location description would be evaluated in the > context of the caller. > --paulr > > From: Dwarf-discuss > <dwarf-discuss-bounces+paul.robinson=sony....@lists.dwarfstd.org> On Behalf > Of Sergey via Dwarf-discuss > Sent: Wednesday, June 12, 2024 9:57 AM > To: dwarf-discuss@lists.dwarfstd.org > Subject: [Dwarf-discuss] Request for clarification of handling stack-passed > parameters > > # Request for clarification of handling stack-passed parameters > > ## Background > > I came across this while parsing parameters of a variadic function in C. > Formal parameters are not sufficient for my case, since all the variadic > arguments are described with a single `DW_TAG_unspecified_parameters`, > whereas reading `DW_TAG_call_site_parameter` allows to get their locations > and values. > > ## Overview > > When generating a DWARF5 of a C function with **more than 6** parameters, the > generated `DW_TAG_call_site` contains only **first 6** > `DW_TAG_call_site_parameter`s (function's `DW_TAG_formal_parameter`s contain > all of them). > > Something I have noticed is that the parameters, which do not get > `DW_TAG_call_site_parameter` generated, are all **passed through > stack**(whereas first 6 through registers), as evident by function's > `DW_TAG_formal_parameter`'s `DW_AT_location` containing `DW_OP_fbreg`. > > ## Request for clarification > > It happens both with gcc and clang, however I was unable to find any > information in the standard regarding generation of only registed-passed > parameters. > > I request clarification on whether it is an issue with implementations, or is > there something in the standard which justifies the described behaviour.
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