[Bug translator/25549] Systemtap unable to find many probe points available in code compiled with LTO enable

[mark at klomp dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=25549

--- Comment #10 from Mark Wielaard <mark at klomp dot org> ---
(In reply to William Cohen from comment #8)
> For the original example that caused the PR to be filed there are many more
> probe (21694 vs 1196) for the lto version, but still an order of magnitude
> less than the non-lto version (255842):
> 
> [wcohen@cervelo BUILDROOT]$ stap -v -L
> 'process("./binutils-2.31.1-29.fc30_gcc_o2_lto_g_.x86_64/usr/bin/ld").
> statement("*@*:*")' |wc
> Pass 1: parsed user script and 577 library scripts using
> 1279164virt/1049920res/13264shr/1036408data kb, in 2230usr/260sys/2499real
> ms.
> Pass 2: analyzed script: 21694 probes, 0 functions, 0 embeds, 0 globals
> using 2078028virt/1843376res/14204shr/1835272data kb, in
> 11060usr/270sys/11552real ms.
>   21694  477333 10389959
> [wcohen@cervelo BUILDROOT]$ stap -v -L
> 'process("./binutils-2.31.1-29.fc30_gcc_o2__g_.x86_64/usr/bin/ld").
> statement("*@*:*")' |wc
> Pass 1: parsed user script and 577 library scripts using
> 1279164virt/1049904res/13252shr/1036408data kb, in 2170usr/270sys/2459real
> ms.
> Pass 2: analyzed script: 255842 probes, 0 functions, 0 embeds, 0 globals
> using 1958204virt/1729244res/14192shr/1715448data kb, in
> 90860usr/10320sys/101800real ms.
>  255842 3891737 96145934

Are there specific probe points that you are missing?

> It would be expected that the lto version would be optimized so there are
> fewer probe points, but 90% reduction in probe points seems unlikely given
> the relative sizes of the binaries:
> 
> [wcohen@cervelo BUILDROOT]$ ls -l
> ./binutils-2.31.1-29.fc30_gcc_o2__g_.x86_64/usr/bin/ld
> -rwxr-xr-x. 2 wcohen wcohen 3941264 Oct 14  2019
> ./binutils-2.31.1-29.fc30_gcc_o2__g_.x86_64/usr/bin/ld
> [wcohen@cervelo BUILDROOT]$ ls -l
> ./binutils-2.31.1-29.fc30_gcc_o2_lto_g_.x86_64/usr/bin/ld
> -rwxr-xr-x. 2 wcohen wcohen 2215376 Oct 14  2019
> ./binutils-2.31.1-29.fc30_gcc_o2_lto_g_.x86_64/usr/bin/ld

Are these binaries available somewhere for inspection?

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