This implements ld64's checks for duplicate method names in categories &
classes.
In addition, this sets us up for implementing Obj-C category merging.
This diff handles the most of the parsing work; what's left is rewriting
those category / class structures.
Numbers for chromium_framework:
base diff difference (95% CI)
sys_time 2.182 ± 0.027 2.200 ± 0.047 [ -0.2% .. +1.8%]
user_time 6.451 ± 0.034 6.479 ± 0.062 [ -0.0% .. +0.9%]
wall_time 6.841 ± 0.048 6.885 ± 0.105 [ -0.1% .. +1.4%]
samples 33 22
Fixes https://github.com/llvm/llvm-project/issues/54912.
Reviewed By: #lld-macho, thevinster, oontvoo
Differential Revision: https://reviews.llvm.org/D142916
This is an NFC diff that prepares for pruning & relocating `__eh_frame`.
Along the way, I made the following changes to ...
* clarify usage of `section` vs. `subsection`
* remove `map` & `vec` from type names
* disambiguate class `Section` from template parameter `SectionHeader`.
Differential Revision: https://reviews.llvm.org/D113241
The previous logic was duplicated between symbol-initiated
archive loads versus flag-initiated loads (i.e. `-force_load` and
`-ObjC`). This resulted in code duplication as well as redundant work --
we would create Archive instances twice whenever we had one of those
flags; once in `getArchiveMembers` and again when we constructed the
ArchiveFile.
This was motivated by an upcoming diff where we load archive members
containing ObjC-related symbols before loading those containing
ObjC-related sections, as well as before performing symbol resolution.
Without this refactor, it would be difficult to do that while avoiding
loading the same archive member twice.
Differential Revision: https://reviews.llvm.org/D108780
@thakis pointed out that `mach_header` and `mach_header_64`
actually have the same set of (used) fields, with the 64-bit version
having extra padding. So we can access the fields we need using the
single `mach_header` type instead of using templates to switch between
the two.
I also spotted a potential issue where hasObjCSection tries to parse a
file w/o checking if it does indeed match the target arch... As such,
I've added a quick magic number check to ensure we don't access invalid
memory during `findCommand()`.
Addresses PR50180.
Reviewed By: #lld-macho, thakis
Differential Revision: https://reviews.llvm.org/D101724
As preparation for a subsequent diff that implements builtin section renaming, define more `constexpr` strings in namespaces `lld::macho::segment_names` and `lld::macho::section_names`, and use them to replace string literals.
Differential Revision: https://reviews.llvm.org/D101393
The main challenge was handling the different on-disk structures (e.g.
`mach_header` vs `mach_header_64`). I tried to strike a balance between
sprinkling `target->wordSize == 8` checks everywhere (branchy = slow, and ugly)
and templatizing everything (causes code bloat, also ugly). I think I struck a
decent balance by judicious use of type erasure.
Note that LLD-ELF has a similar architecture, though it seems to use more templating.
Linking chromium_framework takes about the same time before and after this
change:
N Min Max Median Avg Stddev
x 20 4.52 4.67 4.595 4.5945 0.044423204
+ 20 4.5 4.71 4.575 4.582 0.056344803
No difference proven at 95.0% confidence
Reviewed By: #lld-macho, oontvoo
Differential Revision: https://reviews.llvm.org/D99633
