bug#46256: [feature/native-comp] AOT eln files ignored if run from build tree

[Andrea Corallo]

Andy Moreton <andrewjmoreton@gmail.com> writes:

> On Fri 26 Feb 2021, Andrea Corallo via "Bug reports for GNU Emacs, the Swiss 
> army knife of text editors" wrote:
>
>> Andy Moreton <andrewjmoreton@gmail.com> writes:
>>
>> [...]
>>
>>> The problem is with the file names used to generate the hashes, where
>>> comparison of file names.
>>>
>>> As an experiment, I changed epaths.h from:
>>> #define PATH_DUMPLOADSEARCH "C:/emacs/git/emacs/native/lisp"
>>>
>>> to:
>>> #define PATH_DUMPLOADSEARCH "c:/emacs/git/emacs/native/lisp"
>>>
>>> and then ran make (to build without regenerating the header).
>>> The resulting emacs did not complain about mismatched filenames.
>>>
>>> Thus the fix outlined by Eli above looks like it will solve the problem.
>>>
>>>     AndyM
>>
>> Hi Andy,
>>
>> could you give it a try to the attached patch?  It follows Eli's
>> suggestion of using 'Fw32_long_file_name'.
>
> The patch looks good - please apply it.

Thanks for verifying it, installed as 312deba530.

> I tried building with the patch applied to a clean tree, and the
> resulting emacs runs without the filename mismatch messages, and did not
> recompile the AOT files into the per-user eln-cache.
>
> There were also a couple of errors in the build:
>
> Backtrace:
> 00007ff78467a2a2
> 00007ff78453be26
> 00007ff7845a98ac
> ...[snipped]...
> 00007ff784626548
> Eager macro-expansion failure: (file-error "Renaming" "Permission
> denied"
> "c:/emacs/git/emacs/native/build/mingw64-x86_64-O2-native/native-lisp/28.0.50-e09cfb99/cc-bytecomp-4817e810-d16f606e.eln"
> "c:/emacs/git/emacs/native/build/mingw64-x86_64-O2-native/native-lisp/28.0.50-e09cfb99/cc-bytecomp-4817e810-d16f606e.elnGMMUdn.eln.tmp")
> C:/emacs/git/emacs/native/src/alloc.c:3160: Emacs fatal error: assertion 
> failed: cu->handle
> make[2]: *** [Makefile:319: progmodes/antlr-mode.elc] Error 3
>
> The backtrace addresses did not give anything useful from addr2line.
>
> There are still some elisp files that did not get native compiled when
> the build was done with "make -j8 NATIVE_FULL_AOT=1", and so get async
> compiled when running the built emacs:
>
>   ansi-color auth_source byte-opt bytecomp cconv cl-extra cl-lib cl-macs
>   cl-seq comint comp comp-cstr cus-edit cus-start desktop
>   display-fill-column-indicator easy-mmode easymenu edmacro eieio
>   eieio-core frameset gv help-mode hl-line image-file info json kmacro
>   map minibuf-eldef package paren password-cache pcase pp ring rx seq
>   subr-x time-date warnings wid-edit
>
> That may be a result of the error during the build.

Mmmmh, that's strange some of these are even compiled as COMPILE_FIRST
therfore are certainly native compiled.

One thing you could do (before one of these is recompiled) is to use
`comp-el-to-eln-filename' to check what the native compiler is expecting
as eln filename and if this is present in any of the folders in your
`comp-eln-load-path'.

Thanks

  Andrea