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Re: perl-5.37.5 breaks texinfo-7.0

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Dave Mitchell
November 13, 2022 18:39
Re: perl-5.37.5 breaks texinfo-7.0
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On Sun, Nov 13, 2022 at 07:09:12PM +0100, Uwe Düffert wrote:
> What kind of debugging symbols are you interested in? Last time, one
> suggestion was to build perl with -DDEBBUGGING, but that completely
> concealed the problem,

There are normally 3 main changes made to the perl build process when
enabling debugging:

1) compiler optimisation is turned off
2) full symbol / line info are stored with the executable
3) a whole bunch extra asserts and run-time-switchable debugging output is
baked into the executable.

The build suddenly working is probably down to (1) or maybe (3).
(2) would be most useful to augment valgrind output.

1) is controlled by gcc -O
2) is controlled by gcc -g or gcc -ggdb
3) is controlled by the cpp define DEBUGGING

which in turn are controlled by these perl Configure options:

    ./Configure                 # -O 
    ./Configure -DEBUGGING      # -g and DEBUGGING
    ./Configure -DEBUGGING=-g   # -g
    ./Configure -DEBUGGING=none # 

    ./Configure -DEBUGGING=-g
    ./Configure -DEBUGGING=-g  -Accflags='-ggdb'

is probably the one to try first; otherwise you'll have to experiment a
bit to find what includes debugging symbols. See ./INSTALL for more info.

Another important option is

    ./Configure  -Duseithreads 

which controls whether threads is enabled or not, and can make big changes
to certain type of code (such as globally initialising locate state).

> So does it (expectedly) help if I compile perl with any certain Configure
> switch? And/or run it with any certain environment variable set? Or shall I
> try to provide a stripped down test case instead of saying
> "whole texinfo-7.0 build"?

Well if you can get valgrind to complain about the double free with line
numbers (along with an indication of the args you passed to Configure) it
would be a good place to start. We (or Karl, anyway) can take it from

"But Sidley Park is already a picture, and a most amiable picture too.
The slopes are green and gentle. The trees are companionably grouped at
intervals that show them to advantage. The rill is a serpentine ribbon
unwound from the lake peaceably contained by meadows on which the right
amount of sheep are tastefully arranged." -- Lady Croom, "Arcadia"

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