[PATCH] D37371: [llvm-dwp] Add command line option "-e"

[David Blaikie via llvm-commits]

Given the desire to support interoperability with binutils dwp, if it's
easy enough to support multiple -e (I dunno if LLVM's command line parsing
has nice support for that sort of thing?) maybe that's the best thing.

(if that's difficult, maybe we could be compatible with binutils dwp by
accepting and ignoring '-e' and accepting all executables and dwo files as
described - just searching any file without a debug_info.dwo section, for
any CUs in the debug_info and using those for the input file list)

On Fri, Sep 1, 2017 at 12:34 PM Alexander Shaposhnikov via Phabricator <
reviews at reviews.llvm.org> wrote:

> alexshap added inline comments.
>
>
> ================
> Comment at: tools/llvm-dwp/llvm-dwp.cpp:725-727
> +  ArrayRef<std::string> DWOs = DWOFilenames.empty()
> +                                   ? ArrayRef<std::string>(InputFiles)
> +                                   : ArrayRef<std::string>(DWOFilenames);
> ----------------
> dblaikie wrote:
> > Seems weird to ignore all the other inputs silently if -e is specified.
> Maybe error out if there are both?
> >
> > Alternatively could support both, maybe - more like what I mentioned
> above, even. Could detect that something is an executable/contains skeleton
> units - use those to find DWOs, and treat that as another source of DWOs
> (so you could have arbitrarily many executables and DWOs on the command
> line and they'd all be read and smooshed into a DWP).
> >
> > *shrug* Dunno.
> >
> > What does binutils dwp do if you have both -e and .dwo files? Error?
> yeah,
> i've just looked at binutils dwp ( 2.25.1-22.base.el7).
> Actually binutils dwp behaves differently, it takes everything, i.e.
>
>   [alexshap at devvm32123.prn1 ~/fission/build] dwp c.dwo -e out/libFoo.so
> -o test.dwp
>   [alexshap at devvm32123.prn1 ~/fission/build] cat c.cpp
>   struct XXXXXX {
>     int YYYYYY;
>    };
>
>    int ZZZZZZ() {
>      XXXXXX x;
>      return x.YYYYYY;
>    }
>    [alexshap at devvm32123.prn1 ~/fission/build] strings test.dwp | grep
> ZZZZZZ
>    ZZZZZZ
>    _Z6ZZZZZZv
>
> additionally, binutils dwp allows to pass -e multiple times.
>
> so yes, we can try to replicate this behavior (that looks easy),
> alternatively, we can try to avoid introducing this new flag and try to
> extract the necessary information from the files themselves (i agree, this
> probably would be cleaner, on the down side - requires more work/a bit more
> complex logic + switching back and forth from bintutils version to llvm
> will require changing the invocation)  @dblaikie - how should we proceed ?
>
>
> Repository:
>   rL LLVM
>
> https://reviews.llvm.org/D37371
>
>
>
>
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