tweaks, basic DWARF-based info

[monoidic]

This PR sets up the groundwork for getting DWARF-based info from ELF files, and adds fetching the built-in goroot and build version using it as examples, which currently otherwise require hacks like disassembly of code. The addresses and values of various other values (e.g runtime.firstmoduledata for the moduledata, or various type definitions) could be located as well.
This, of course, has the drawback of only working on ELF and requiring DWARF to not be stripped, though it should be portable across all Go platforms which use ELF, both by OS and CPU architecture. And DWARF is, by default, included.

This PR also includes some housekeeping and tweaks:

• bumping dependencies
• simplifying typeOffset()
• renaming getSectionDataFromOffset to getSectionDataFromAddress for clarity (the "offset" passed as an argument is a memory address, not a file offset)
• replace uses of the deprecated io/ioutil module with equivalent code
• replace some f.Seek(x, 0) calls with f.Seek(x, io.SeekStart) to remove the magic value
• run go generate to update gopkg_gen.go and stdpkg_gen.go
• fix some typoes
• do not silently ignore some error values
• update tests to handle go.12.0 correctly and add said version to testdata/build.go (todo: PR to /goretk/testdata)

[monoidic]

And autogenerating the code for the moduledata{version}{machine_word_size} structs + converting them to moduledata without using any (runtime) reflection.
I also took the liberty of trimming the definitions down to the last actually used field. Go 1.21 changed the definition of the moduledata struct, but until inittasks itself (which could be interesting) or any of the fields succeeding it are used, it won't make any difference here.

[TcM1911]

Thank you for contributing. I will make time to review this by the end of this week.

[Zxilly]

Any further work on this patch? I can help to merge this.

[TcM1911]

The conflicts must be fixed. It would probably be best also to break out the moduledata and the DWARF extraction into separate PRs.

[monoidic]

Oh, I'd forgotten about this PR.

The conflicts must be fixed. It would probably be best also to break out the moduledata and the DWARF extraction into separate PRs.

Very well, I will wait for #77 to be accepted and then rework this PR.

[TcM1911]

#77 has been merged.

[codecov-commenter]

Codecov Report

Attention: 37 lines in your changes are missing coverage. Please review.

Comparison is base (6d39e92) 78.87% compared to head (76855ef) 78.57%.
Report is 1 commits behind head on develop.

Files	Patch %	Lines
dwarf.go	74.28%	19 Missing and 8 partials ⚠️
goversion.go	20.00%	3 Missing and 1 partial ⚠️
goroot.go	25.00%	2 Missing and 1 partial ⚠️
type.go	85.00%	3 Missing ⚠️

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Additional details and impacted files

@@             Coverage Diff             @@
##           develop      #69      +/-   ##
===========================================
- Coverage    78.87%   78.57%   -0.30%     
===========================================
  Files           15       16       +1     
  Lines         3474     3589     +115     
===========================================
+ Hits          2740     2820      +80     
- Misses         518      543      +25     
- Partials       216      226      +10     

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📢 Have feedback on the report? Share it here.

[Zxilly]

Maybe we can add some sample with debug info to gold.

[Zxilly]

I noticed macho.File also has a https://pkg.go.dev/debug/macho#File.DWARF method, can this logic also applied to macho?

[Zxilly]

Even debug/pe also has a https://pkg.go.dev/debug/pe#File.DWARF. And all of them use the debug/dwarf.
This made me curious, as I always thought pe files used a separate PDB debug info file

[monoidic]

Huh, you're right, @Zxilly . Somewhat surprised to see that PE is on that list.

I gave the fileHandler interface a getDwarf method to get the DWARF data and just made the DWARF data extraction code use fileHandler, so it works across all binary formats.

[Zxilly]

lgtm

[Zxilly]

hope this PR get merged soon as it may conflicted with #86, blocking the further development

[monoidic]

Rebased to fix conflicts.

[TcM1911]

There is a lot of places where it results in a panic. Since this is a library, I think we should try to not bring down the main application if we can. Please switch to errors instead.

It could be good to add some tests too. Either by using "golden" binaries or building some on the fly like it's done in https://github.com/goretk/gore/blob/develop/slow_test.go.

[monoidic]

Those panics were definitely not intended to be there, whoops.
I thought I'd have to have a chicken-or-egg issue with pushing unstripped test binaries to the testdata. But slow_test works.
I have to use a different source file if I want getGoRootFromDwarf to succeed as runtime.defaultGOROOT is not included unless needed.

Also, the tmpDirs slice in TestMain in slow_test was not previously collecting all temporary directories and a bunch of build files were getting left behind. I fixed that.

[TcM1911]

Minor fix needed and this is ready to be merged.

[Zxilly]

The CI error was caused by go 1.22, which moduledata currently not exist in the main branch. After #88 merged it gets resolved.

[TcM1911]

#88 has been merged. Please try again.

[Zxilly]

Seems works fine now.