[Git][ghc/ghc][wip/dwarf-info-offset] 10 commits: nativeGen: Make makeImportsDoc take an NCGConfig rather than DynFlags

Thu Nov 12 21:59:45 UTC 2020

Ben Gamari pushed to branch wip/dwarf-info-offset at Glasgow Haskell Compiler / GHC

Commits:
fcfda909 by Ben Gamari at 2020-11-11T03:19:59-05:00
nativeGen: Make makeImportsDoc take an NCGConfig rather than DynFlags

It appears this was an oversight as there is no reason the full DynFlags
is necessary.

- - - - -
6e23695e by Ben Gamari at 2020-11-11T03:19:59-05:00
Move this_module into NCGConfig

In various places in the NCG we need the Module currently being
compiled. Let's move this into the environment instead of chewing threw
another register.

- - - - -
c6264a2d by Ben Gamari at 2020-11-11T03:20:00-05:00
codeGen: Produce local symbols for module-internal functions

It turns out that some important native debugging/profiling tools (e.g.
perf) rely only on symbol tables for function name resolution (as
opposed to using DWARF DIEs). However, previously GHC would emit
temporary symbols (e.g. `.La42b`) to identify module-internal
entities. Such symbols are dropped during linking and therefore not
visible to runtime tools (in addition to having rather un-helpful unique
names). For instance, `perf report` would often end up attributing all
cost to the libc `frame_dummy` symbol since Haskell code was no covered
by any proper symbol (see #17605).

We now rather follow the model of C compilers and emit
descriptively-named local symbols for module internal things. Since this
will increase object file size this behavior can be disabled with the
`-fno-expose-internal-symbols` flag.

With this `perf record` can finally be used against Haskell executables.
Even more, with `-g3` `perf annotate` provides inline source code.

- - - - -
584058dd by Ben Gamari at 2020-11-11T03:20:00-05:00
Enable -fexpose-internal-symbols when debug level >=2

This seems like a reasonable default as the object file size increases
by around 5%.

- - - - -
c34a4b98 by Ömer Sinan Ağacan at 2020-11-11T03:20:35-05:00
Fix and enable object unloading in GHCi

Fixes #16525 by tracking dependencies between object file symbols and
marking symbol liveness during garbage collection

See Note [Object unloading] in CheckUnload.c for details.

- - - - -
2782487f by Ray Shih at 2020-11-11T03:20:35-05:00
Add loadNativeObj and unloadNativeObj

(This change is originally written by niteria)

This adds two functions:
* `loadNativeObj`
* `unloadNativeObj`
and implements them for Linux.

They are useful if you want to load a shared object with Haskell code
using the system linker and have GHC call dlclose() after the
code is no longer referenced from the heap.

Using the system linker allows you to load the shared object
above outside the low-mem region. It also loads the DWARF sections
in a way that `perf` understands.

`dl_iterate_phdr` is what makes this implementation Linux specific.

- - - - -
7a65f9e1 by GHC GitLab CI at 2020-11-11T03:20:35-05:00
rts: Introduce highMemDynamic

- - - - -
e9e1b2e7 by GHC GitLab CI at 2020-11-11T03:20:35-05:00
Introduce test for dynamic library unloading

This uses the highMemDynamic flag introduced earlier to verify that
dynamic objects are properly unloaded.

- - - - -
5506f134 by Krzysztof Gogolewski at 2020-11-11T03:21:14-05:00
Force argument in setIdMult (#18925)

- - - - -
160ce150 by Ben Gamari at 2020-11-12T16:59:37-05:00
dwarf: Apply info table offset consistently

Previously we failed to apply the info table offset to the aranges and
DIEs, meaning that we often failed to unwind in gdb. For some reason
this only seemed to manifest in the RTS's Cmm closures. Nevertheless,
now we can unwind completely up to `main`

- - - - -

30 changed files:

- compiler/GHC/Cmm/CLabel.hs
- compiler/GHC/Cmm/Info/Build.hs
- compiler/GHC/CmmToAsm.hs
- compiler/GHC/CmmToAsm/Config.hs
- compiler/GHC/CmmToAsm/Dwarf/Types.hs
- compiler/GHC/CmmToAsm/Monad.hs
- compiler/GHC/CmmToAsm/PIC.hs
- compiler/GHC/CmmToAsm/X86/Ppr.hs
- compiler/GHC/Driver/Flags.hs
- compiler/GHC/Driver/Session.hs
- compiler/GHC/Linker/Loader.hs
- compiler/GHC/Types/Var.hs
- docs/users_guide/debug-info.rst
- docs/users_guide/phases.rst
- includes/rts/Linker.h
- includes/rts/storage/GC.h
- rts/CheckUnload.c
- rts/CheckUnload.h
- rts/Hash.c
- rts/Hash.h
- rts/Linker.c
- rts/LinkerInternals.h
- rts/RtsStartup.c
- rts/linker/Elf.c
- rts/linker/LoadArchive.c
- rts/linker/MachO.c
- rts/linker/PEi386.c
- rts/linker/elf_got.c
- rts/sm/Evac.c
- rts/sm/GC.c

The diff was not included because it is too large.

View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/0e46fa9ea25804ea3d2eef79b38e963e96456ba2...160ce15024054ac20f52b3ecaea20d86bb5b8b54

-- 
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/0e46fa9ea25804ea3d2eef79b38e963e96456ba2...160ce15024054ac20f52b3ecaea20d86bb5b8b54
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