[Git][ghc/ghc][wip/marge_bot_batch_merge_job] 6 commits: Prefer packed representation for CompiledByteCode

[Marge Bot (@marge-bot)]

Marge Bot pushed to branch wip/marge_bot_batch_merge_job at Glasgow Haskell Compiler / GHC


Commits:
cdb6f870 by Fendor at 2024-04-08T20:29:05-04:00
Prefer packed representation for CompiledByteCode

As there are many 'CompiledByteCode' objects alive during a GHCi
session, representing its element in a more packed manner improves space
behaviour at a minimal cost.

When running GHCi on the agda codebase, we find around 380 live
'CompiledByteCode' objects. Packing their respective 'UnlinkedByteCode'
can save quite some pointers.

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f9b7e2ef by Rodrigo Mesquita at 2024-04-08T20:29:05-04:00
rts: free error message before returning

Fixes a memory leak in rts/linker/PEi386.c

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57751952 by Alexis King at 2024-04-08T20:29:05-04:00
linker: Avoid linear search when looking up Haskell symbols via dlsym

See the primary Note [Looking up symbols in the relevant objects] for a
more in-depth explanation.

When dynamically loading a Haskell symbol (typical when running a splice or
GHCi expression), before this commit we would search for the symbol in
all dynamic libraries that were loaded. However, this could be very
inefficient when too many packages are loaded (which can happen if there are
many package dependencies) because the time to lookup the would be
linear in the number of packages loaded.

This commit drastically improves symbol loading performance by
introducing a mapping from units to the handles of corresponding loaded
dlls. These handles are returned by dlopen when we load a dll, and can
then be used to look up in a specific dynamic library.

Looking up a given Name is now much more precise because we can get
lookup its unit in the mapping and lookup the symbol solely in the
handles of the dynamic libraries loaded for that unit.

In one measurement, the wait time before the expression was executed
went from +-38 seconds down to +-2s.

This commit also includes Note [Symbols may not be found in pkgs_loaded],
explaining the fallback to the old behaviour in case no dll can be found
in the unit mapping for a given Name.

Fixes #23415

Co-authored-by: Rodrigo Mesquita (@alt-romes)

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21e29f91 by Rodrigo Mesquita at 2024-04-08T20:29:05-04:00
rts: Make addDLL a wrapper around loadNativeObj

Rewrite the implementation of `addDLL` as a wrapper around the more
principled `loadNativeObj` rts linker function. The latter should be
preferred while the former is preserved for backwards compatibility.

`loadNativeObj` was previously only available on ELF platforms, so this
commit further refactors the rts linker to transform loadNativeObj_ELF
into loadNativeObj_POSIX, which is available in ELF and MachO platforms.

The refactor made it possible to remove the `dl_mutex` mutex in favour
of always using `linker_mutex` (rather than a combination of both).

Lastly, we implement `loadNativeObj` for Windows too.

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3c2e8fc3 by Rodrigo Mesquita at 2024-04-08T20:29:05-04:00
Use symbol cache in internal interpreter too

This commit makes the symbol cache that was used by the external
interpreter available for the internal interpreter too.

This follows from the analysis in #23415 that suggests the internal
interpreter could benefit from this cache too, and that there is no good
reason not to have the cache for it too. It also makes it a bit more
uniform to have the symbol cache range over both the internal and
external interpreter.

This commit also refactors the cache into a function which is used by
both `lookupSymbol` and also by `lookupSymbolInDLL`, extending the
caching logic to `lookupSymbolInDLL` too.

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5bcbb4d9 by Ben Gamari at 2024-04-08T20:29:05-04:00
testsuite: Add test for lookupSymbolInNativeObj

- - - - -


30 changed files:

- compiler/GHC.hs
- compiler/GHC/ByteCode/Asm.hs
- compiler/GHC/ByteCode/Linker.hs
- compiler/GHC/ByteCode/Types.hs
- compiler/GHC/Data/FlatBag.hs
- compiler/GHC/Driver/Main.hs
- compiler/GHC/Driver/Plugins.hs
- compiler/GHC/Linker/Loader.hs
- compiler/GHC/Linker/MacOS.hs
- compiler/GHC/Linker/Types.hs
- compiler/GHC/Runtime/Interpreter.hs
- compiler/GHC/Runtime/Interpreter/JS.hs
- compiler/GHC/Runtime/Interpreter/Types.hs
- compiler/GHC/StgToByteCode.hs
- libraries/ghci/GHCi/Message.hs
- libraries/ghci/GHCi/ObjLink.hs
- libraries/ghci/GHCi/Run.hs
- rts/Linker.c
- rts/LinkerInternals.h
- rts/RtsSymbols.c
- rts/include/rts/Linker.h
- rts/linker/Elf.c
- rts/linker/Elf.h
- + rts/linker/LoadNativeObjPosix.c
- + rts/linker/LoadNativeObjPosix.h
- rts/linker/PEi386.c
- rts/linker/PEi386.h
- rts/rts.cabal
- testsuite/tests/ghci/linking/dyn/T3372.hs
- testsuite/tests/rts/linker/T2615.hs


The diff was not included because it is too large.


View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/d06cdbb5ee5cbabec81daaeca9414d6867250133...5bcbb4d9027438a77a0befd265a269be3b7c4c53

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View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/d06cdbb5ee5cbabec81daaeca9414d6867250133...5bcbb4d9027438a77a0befd265a269be3b7c4c53
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