Commit Graph

17 Commits

Author SHA1 Message Date
Greg McGary 87104faac4 [lld-macho] Add ARM64 target arch
This is an initial base commit for ARM64 target arch support. I don't represent that it complete or bug-free, but wish to put it out for review now that some basic things like branch target & load/store address relocs are working.

I can add more tests to this base commit, or add them in follow-up commits.

It is not entirely clear whether I use the "ARM64" (Apple) or "AArch64" (non-Apple) naming convention. Guidance is appreciated.

Differential Revision: https://reviews.llvm.org/D88629
2021-02-08 18:14:07 -07:00
Jez Ng f843bb82c0 [lld-macho] Force-loading should share code path with regular archive loads
This extends {D92539} to work even when we are loading archive
members via `-force_load`. I uncovered this issue while trying to
force-load archives containing bitcode -- we were segfaulting.

In addition to fixing the `-force_load` case, this diff also addresses
the behavior of `-ObjC` when LTO bitcode is involved -- we need to
force-load those archive members if they contain ObjC categories.

Reviewed By: #lld-macho, smeenai

Differential Revision: https://reviews.llvm.org/D95265
2021-02-03 13:43:47 -05:00
Jez Ng 3dd5ea9dd8 [lld-macho] Link against ObjCARCOpts instead of ObjCARC
Not sure what the difference is, but using the latter appears to cause
issues in standalone builds. See llvm.org/PR48853.

Reviewed By: #lld-macho, compnerd

Differential Revision: https://reviews.llvm.org/D95359
2021-01-25 19:01:48 -05:00
Jez Ng 34e8fcf63f [lld-macho] Add dependency on ObjCARC to fix shared build 2021-01-20 20:41:51 -05:00
Heejin Ahn 6fb88c6cd5 [lld-macho] Add dependency to DebugInfoDWARF
Without this `-DBUILD_SHARED_LIBS=ON` doesn't work.
2020-12-01 19:10:46 -08:00
Jez Ng 3fcb0eeb15 [lld-macho] Emit STABS symbols for debugging, and drop debug sections
Debug sections contain a large amount of data. In order not to bloat the size
of the final binary, we remove them and instead emit STABS symbols for
`dsymutil` and the debugger to locate their contents in the object files.

With this diff, `dsymutil` is able to locate the debug info. However, we need
a few more features before `lldb` is able to work well with our binaries --
e.g. having `LC_DYSYMTAB` accurately reflect the number of local symbols,
emitting `LC_UUID`, and more. Those will be handled in follow-up diffs.

Note also that the STABS we emit differ slightly from what ld64 does. First, we
emit the path to the source file as one `N_SO` symbol instead of two. (`ld64`
emits one `N_SO` for the dirname and one of the basename.) Second, we do not
emit `N_BNSYM` and `N_ENSYM` STABS to mark the start and end of functions,
because the `N_FUN` STABS already serve that purpose. @clayborg recommended
these changes based on his knowledge of what the debugging tools look for.

Additionally, this current implementation doesn't accurately reflect the size
of function symbols. It uses the size of their containing sectioins as a proxy,
but that is only accurate if `.subsections_with_symbols` is set, and if there
isn't an `N_ALT_ENTRY` in that particular subsection. I think we have two
options to solve this:

1. We can split up subsections by symbol even if `.subsections_with_symbols`
   is not set, but include constraints to ensure those subsections retain
   their order in the final output. This is `ld64`'s approach.
2. We could just add a `size` field to our `Symbol` class. This seems simpler,
   and I'm more inclined toward it, but I'm not sure if there are use cases
   that it doesn't handle well. As such I'm punting on the decision for now.

Reviewed By: clayborg

Differential Revision: https://reviews.llvm.org/D89257
2020-12-01 15:05:20 -08:00
Jez Ng 21f831134c [lld-macho] Add very basic support for LTO
Just enough to consume some bitcode files and link them. There's more
to be done around the symbol resolution API and the LTO config, but I don't yet
understand what all the various LTO settings do...

Reviewed By: #lld-macho, compnerd, smeenai, MaskRay

Differential Revision: https://reviews.llvm.org/D90663
2020-11-10 12:19:28 -08:00
Greg McGary 2124ca1d5c [lld-macho] create __TEXT,__unwind_info from __LD,__compact_unwind
Digest the input `__LD,__compact_unwind` and produce the output `__TEXT,__unwind_info`. This is the initial commit with the major functionality.

Successor commits will add handling for ...
* `__TEXT,__eh_frame`
* personalities & LSDA
* `-r` pass-through

Differential Revision: https://reviews.llvm.org/D86805
2020-09-18 22:01:03 -07:00
Jez Ng cf918c809b [lld-macho] Implement -ObjC
It's roughly like -force_load with some filtering.

Differential Revision: https://reviews.llvm.org/D86181
2020-08-26 19:20:55 -07:00
Jez Ng 7394460d87 [lld-macho] Handle TAPI and regular re-exports uniformly
The re-exports list in a TAPI document can either refer to other inlined
TAPI documents, or to on-disk files (which may themselves be TBD or
regular files.) Similarly, the re-exports of a regular dylib can refer
to a TBD file.

Differential Revision: https://reviews.llvm.org/D85404
2020-08-26 19:20:48 -07:00
Michael Liao 43793b89a0 [lld] Fix shared library build by adding the missing dependency. 2020-06-08 16:12:58 -04:00
Kellie Medlin 6cb073133c [lld] Merge Mach-O input sections
Summary: Similar to other formats, input sections in the MachO
implementation are now grouped under output sections. This is primarily
a refactor, although there's some new logic (like resolving the output
section's flags based on its inputs).

Differential Revision: https://reviews.llvm.org/D77893
2020-05-01 16:57:18 -07:00
Jez Ng 9854edd817 [lld-macho] Implement basic export trie
Build the trie by performing a three-way radix quicksort: We start by
sorting the strings by their first characters, then sort the strings
with the same first characters by their second characters, and so on
recursively. Each time the prefixes diverge, we add a node to the trie.
Thanks to @ruiu for the idea.

I used llvm-mc's radix quicksort implementation as a starting point. The
trie offset fixpoint code was taken from
MachONormalizedFileBinaryWriter.cpp.

Differential Revision: https://reviews.llvm.org/D76977
2020-04-29 15:44:27 -07:00
Jez Ng 060efd24c7 [lld-macho] Add basic support for linking against dylibs
This diff implements:

* dylib loading (much of which is being restored from @pcc and @ruiu's
  original work)
* The GOT_LOAD relocation, which allows us to load non-lazy dylib
  symbols
* Basic bind opcode emission, which tells `dyld` how to populate the GOT

Differential Revision: https://reviews.llvm.org/D76252
2020-04-21 13:43:19 -07:00
Fangrui Song 6acd300375 Reland D75382 "[lld] Initial commit for new Mach-O backend"
With a fix for http://lab.llvm.org:8011/builders/clang-cmake-armv8-lld/builds/3636

Also trims some unneeded dependencies.
2020-04-02 12:03:43 -07:00
Oliver Stannard af39151f3c Revert "[lld] Initial commit for new Mach-O backend"
This is causing buildbot failures on 32-bit hosts, for example:
http://lab.llvm.org:8011/builders/clang-cmake-armv8-lld/builds/3636

This reverts commit 03f43b3aca.
2020-04-02 13:23:30 +01:00
Jez Ng 03f43b3aca [lld] Initial commit for new Mach-O backend
Summary:
This is the first commit for the new Mach-O backend, designed to roughly
follow the architecture of the existing ELF and COFF backends, and
building off work that @ruiu and @pcc did in a branch a while back. Note
that this is a very stripped-down commit with the bare minimum of
functionality for ease of review. We'll be following up with more diffs
soon.

Currently, we're able to generate a simple "Hello World!" executable
that runs on OS X Catalina (and possibly on earlier OS X versions; I
haven't tested them). (This executable can be obtained by compiling
`test/MachO/relocations.s`.) We're mocking out a few load commands to
achieve this -- for example, we can't load dynamic libraries, but
Catalina requires binaries to be linked against `dyld`, so we hardcode
the emission of a `LC_LOAD_DYLIB` command. Other mocked out load
commands include LC_SYMTAB and LC_DYSYMTAB.

Differential Revision: https://reviews.llvm.org/D75382
2020-03-31 11:58:47 -07:00