Commit Graph

178 Commits

Author SHA1 Message Date
Jez Ng 0f8854f7f5 [lld-macho] Don't reference entry symbol for non-executables
This would cause us to pull in symbols (and code) that should
be unused.

Reviewed By: #lld-macho, thakis

Differential Revision: https://reviews.llvm.org/D102137
2021-05-09 20:30:26 -04:00
Greg McGary 5be8502271 [lld-macho] Explicitly undefine literal exported symbols
Symbols explicitly exported via command-line options `--exported_symbol SYM` and `--exported_symbols_list FILE` must be defined. Before this fix, lazy symbols defined in archives would be left to languish. We now force them to be included in the linked output.

Differential Revision: https://reviews.llvm.org/D102100
2021-05-08 11:37:00 -07:00
Jez Ng 20f51ffe67 [lld-macho] Have --reproduce account for path rerooting
We need to account for path rerooting when generating the response
file. We could either reroot the paths before generating the file, or pass
through the original filenames and change just the syslibroot. I've opted for
the latter, in order that the reproduction run more closely mirrors the
original.

We must also be careful *not* to make an absolute path relative if it is
shadowed by a rerooted path. See repro6.tar in reroot-path.s for
details.

I've moved the call to `createResponseFile()` after the initialization of
`config->systemLibraryRoots`, since it now needs to know what those roots are.

Reviewed By: #lld-macho, oontvoo

Differential Revision: https://reviews.llvm.org/D101224
2021-05-05 14:41:01 -04:00
Greg McGary 27b426b0c8 [lld-macho] Implement builtin section renaming
ld64 automatically renames many sections depending on output type and assorted flags. Here, we implement the most common configs. We can add more obscure flags and behaviors as needed.

Depends on D101393

Differential Revision: https://reviews.llvm.org/D101395
2021-05-03 21:26:51 -07:00
Jez Ng 001ba65375 [lld-macho] De-templatize mach_header operations
@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
2021-05-03 18:31:23 -04:00
Jez Ng 05c5363b39 [lld-macho] Parse & emit the N_ARM_THUMB_DEF symbol flag
Eventually we'll use this flag to properly handle bl/blx
opcodes.

Reviewed By: #lld-macho, gkm

Differential Revision: https://reviews.llvm.org/D101558
2021-04-30 16:17:26 -04:00
Jez Ng 2d28100bf2 [lld-macho] Initial scaffolding for ARM32 support
This just parses the `-arch armv7` and emits the right header flags.
The rest will be slowly fleshed out in upcoming diffs.

Reviewed By: #lld-macho, gkm

Differential Revision: https://reviews.llvm.org/D101557
2021-04-30 16:17:25 -04:00
Jez Ng 7e115da5df [lld-macho] Make everything PIE by default
Modern versions of macOS (>= 10.7) and in general all modern Mach-O
target archs want PIEs by default. ld64 defaults to PIE for iOS >= 4.3,
as well as for all versions of watchOS and simulators. Basically all the
platforms LLD is likely to target want PIE. So instead of cluttering LLD's
code with legacy version checks, I think it's simpler to just default to
PIE for everything.

Note that `-no_pie` still works, so users can still opt out of it.

Reviewed By: #lld-macho, thakis, MaskRay

Differential Revision: https://reviews.llvm.org/D101513
2021-04-29 15:11:23 -04:00
Greg McGary c2419aae76 [lld-macho] Add option --error-limit=N
Add option to limit (or remove limits) on the number of errors printed before exiting. This option exists in the other lld ports: COFF & ELF.

Differential Revision: https://reviews.llvm.org/D101274
2021-04-26 07:10:12 -07:00
Jez Ng ed4a4e3312 [lld-macho][nfc] Add accessors for commonly-used PlatformInfo fields
As discussed here: https://reviews.llvm.org/D100523#inline-951543

Reviewed By: #lld-macho, thakis, alexshap

Differential Revision: https://reviews.llvm.org/D100978
2021-04-21 15:43:56 -04:00
Jez Ng ab9c21bbab [lld-macho] Support LC_ENCRYPTION_INFO
This load command records a range spanning from the end of the load
commands to the end of the `__TEXT` segment. Presumably the kernel will encrypt
all this data.

Reviewed By: #lld-macho, thakis

Differential Revision: https://reviews.llvm.org/D100973
2021-04-21 13:39:56 -04:00
Alexander Shaposhnikov 5c835e1ae5 [lld][MachO] Add support for LC_VERSION_MIN_* load commands
This diff adds initial support for the legacy LC_VERSION_MIN_* load commands.

Test plan: make check-lld-macho

Differential revision: https://reviews.llvm.org/D100523
2021-04-21 05:41:14 -07:00
Jez Ng ca6751043d [lld-macho] Initial groundwork for -bitcode_bundle
This diff creates an empty XAR file and copies it into
`__LLVM,__bundle`. Follow-up work will actually populate the contents of
that XAR.

Reviewed By: #lld-macho, gkm

Differential Revision: https://reviews.llvm.org/D100650
2021-04-16 16:47:14 -04:00
Jez Ng 3bc88eb392 [lld-macho] Add support for arm64_32
From what I can tell, it's pretty similar to arm64. The two main differences
are:

1. No 64-bit relocations
2. Stub code writes to 32-bit registers instead of 64-bit

Plus of course the various on-disk structures like `segment_command` are using
the 32-bit instead of the 64-bit variants.

Reviewed By: #lld-macho, gkm

Differential Revision: https://reviews.llvm.org/D99822
2021-04-15 21:16:33 -04:00
Jez Ng db7a413e51 [lld-macho] Re-root absolute input file paths if -syslibroot is specified
Reviewed By: #lld-macho, gkm

Differential Revision: https://reviews.llvm.org/D100147
2021-04-15 21:16:33 -04:00
Jez Ng 8ca366935b Revert "[lld-macho] Add support for arm64_32" and other stacked diffs
This reverts commits:
* 8914902b01
* 35a745d814
* 682d1dfe09
2021-04-13 12:40:58 -04:00
Jez Ng 84c52f3a19 [lld-macho] arm64_32 executables are always PIE
This should fix the assert that's currently breaking the build.
2021-04-13 11:55:45 -04:00
Jez Ng 8914902b01 [lld-macho] Add support for arm64_32
From what I can tell, it's pretty similar to arm64. The two main differences
are:

1. No 64-bit relocations
2. Stub code writes to 32-bit registers instead of 64-bit

Plus of course the various on-disk structures like `segment_command` are using
the 32-bit instead of the 64-bit variants.

Reviewed By: #lld-macho, gkm

Differential Revision: https://reviews.llvm.org/D99822
2021-04-13 10:43:28 -04:00
Jez Ng c2e76a9a6d [lld-macho][nfc] Use varargs form of hasArg() 2021-04-08 14:12:55 -04:00
Jez Ng c23b92acd0 [lld-macho] Support -add_ast_path
Swift builds seem to use it. All it requires is emitting the
corresponding paths as STABS.

Fixes llvm.org/PR49385.

Reviewed By: clayborg

Differential Revision: https://reviews.llvm.org/D100076
2021-04-08 14:12:55 -04:00
Jez Ng 050a7a27ca [lld-macho] Support --thinlto-jobs
The test is loosely based off LLD-ELF's `thinlto.ll`. However, I
found that test questionable because the the -save_temps behavior it
checks for is identical regardless of whether we are running in single-
or multi-threaded mode. I tried writing a test based on `--time-trace`
but couldn't get it to run deterministically... so I've opted to just
skip checking that behavior for now.

Reviewed By: #lld-macho, gkm

Differential Revision: https://reviews.llvm.org/D99356
2021-04-08 12:21:01 -04:00
Vy Nguyen db851dfb49 [lld-macho] Make time-trace* options more permissive.
If either `time-trace-granularity` or `time-trace-file` is specified, then don't make users specify `-time-trace`.
It seems silly that I have to type all three options, eg, `-time-trace -time-trace-file=- -time-trace-granularity=...`.

Differential Revision: https://reviews.llvm.org/D100011
2021-04-07 16:00:20 -04:00
Vy Nguyen ffc65824f0 [lld-macho][nfc] Minor refactoring + clang-tidy fixes
- use "empty()" instead of "size()"
- refactor the re-export code so it doesn't create a new vector every time.

Differential Revision: https://reviews.llvm.org/D100019
2021-04-07 13:55:52 -04:00
Jez Ng 174deb0539 [lld-macho] clang-format cleanup
find . -type f -name "*.cpp" -o -name "*.h" | xargs clang-format -i
2021-04-06 14:26:13 -04:00
Jez Ng e0df2b540a [lld-macho] Rename SubsectionMapping to SubsectionMap
We bikeshedded about it here: https://reviews.llvm.org/D98837#inline-931557

I initially suggested SubsectionMapping, but I thought the discussion
landed on doing `std::vector<SubsectionEntry>`. @alexshap went and did
both, but on hindsight I regret adding 3 more characters to an already
long name, and I think SubsectionEntry is descriptive enough...

This diff also renames `subsectionMap` to `subsecMap` for consistency
with other variable names in the codebase.
2021-04-06 14:26:13 -04:00
Cyndy Ishida 0116d04d04 [TextAPI] move source code files out of subdirectory, NFC
TextAPI/ELF has moved out into InterfaceStubs, so theres no longer a
need to seperate out TextAPI between formats.

Reviewed By: ributzka, int3, #lld-macho

Differential Revision: https://reviews.llvm.org/D99811
2021-04-05 10:24:42 -07:00
Jez Ng 817d98d841 [lld-macho][nfc] Refactor in preparation for 32-bit support
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
2021-04-02 18:46:39 -04:00
Alexander Shaposhnikov f6ad045366 [lld][MachO] Make emitEndFunStab independent from .subsections_via_symbols
This diff addresses FIXME in SyntheticSections.cpp and removes
the dependency of emitEndFunStab on .subsections_via_symbols.

Test plan: make check-lld-macho

Differential revision: https://reviews.llvm.org/D99054
2021-04-01 17:48:09 -07:00
Alexander Shaposhnikov f1e4e2fb20 [lld][MachO] Refactor handling of subsections
This diff is a preparation for fixing FunStabs (incorrect size calculation).
std::map<uint32_t, InputSection*> (SubsectionMap) is replaced with
a sorted vector + binary search. If .subsections_via_symbols is set
this vector will contain the list of subsections, otherwise,
the offsets will be used for calculating the symbols sizes.

Test plan: make check-all

Differential revision: https://reviews.llvm.org/D98837
2021-03-31 16:52:53 -07:00
Greg McGary 427d359721 [lld-macho][NFC] Drop unnecessary macho:: namespace prefix on unambiguous references to Symbol
Within `lld/macho/`, only `InputFiles.cpp` and `Symbols.h` require the `macho::` namespace qualifier to disambiguate references to `class Symbol`.

Add braces to outer `for` of a 5-level single-line `if`/`for` nest.

Differential Revision: https://reviews.llvm.org/D99555
2021-03-30 14:58:35 -07:00
Jez Ng a43f588e01 [lld-macho] Implement -segprot
Addresses llvm.org/PR49405.

Reviewed By: #lld-macho, oontvoo

Differential Revision: https://reviews.llvm.org/D99389
2021-03-29 14:08:12 -04:00
Jez Ng 94e369400e [lld-macho] Fix parsing of --time-trace-{granularity,file}
Summary: We needed to use `Joined` instead of `Flag`. This wasn't caught
because the relevant test that was copied from LLD-ELF was still
invoking LLD-ELF instead of LLD-MachO...

Differential Revision: https://reviews.llvm.org/D99313
2021-03-26 18:14:10 -04:00
Jez Ng 45cdceb40c [lld-macho] Support -no_function_starts
Pretty simple code-wise. Also threw in some refactoring:

* Put the functionStartSection under Writer instead of InStruct, since
  it doesn't need to be accessed outside of Writer
* Adjusted the test to put all files under the temp dir instead of at
  the top-level
* Added some CHECK-LABELs to make it clearer where the function starts
  data is

Differential Revision: https://reviews.llvm.org/D99112
2021-03-26 18:14:10 -04:00
Jez Ng 0113cf00b6 [lld-macho] Add support for --threads
Code and test are largely identical to the LLD-ELF equivalents.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D99312
2021-03-25 14:51:31 -04:00
Jez Ng 4bcaafeb0e [lld-macho] Add more TimeTraceScopes
I added just enough to allow us to see a top-level breakdown of time taken. This
is the result of loading the time-trace output into `chrome:://tracing`:

ef5e8234f3/tracing.png

Reviewed By: oontvoo

Differential Revision: https://reviews.llvm.org/D99311
2021-03-25 14:51:31 -04:00
Jez Ng 53fd1ada76 [lld-macho] Fix typo in diagnostic message 2021-03-25 14:51:31 -04:00
Vy Nguyen f499b932bf Revert "Revert "Revert "Revert "Revert "Revert "[lld-macho] Implement -dependency_info (partially - more opcodes needed)""""""
This reverts commit 4876ba5b2d.

Third-attemp relanding D98559, new change:
  - explicitly cast enum to underlying type to avoid ambiguity (workaround to clang's bug).
2021-03-23 14:51:05 -04:00
Mehdi Amini 4876ba5b2d Revert "Revert "Revert "Revert "Revert "[lld-macho] Implement -dependency_info (partially - more opcodes needed)"""""
This reverts commit 3c21166a94.
The build is broken (clang-8 host compiler):

lld/MachO/DriverUtils.cpp:271:8: error: use of overloaded operator '<<' is ambiguous (with operand types 'llvm::raw_fd_ostream' and 'lld::macho::DependencyTracker::DepOpCode')
    os << opcode;
    ~~ ^  ~~~~~~
2021-03-23 00:19:12 +00:00
Vy Nguyen 3c21166a94 Revert "Revert "Revert "Revert "[lld-macho] Implement -dependency_info (partially - more opcodes needed)""""
This reverts commit 9670d2e4af.

Second attemp to reland D98559. New changes:
 - inline functions removed from cpp file.
 - updated tests to use CHECK-DAG instead of CHECK-NEXT
 - fixed ambiguous "<<" operator by switching `char` to uint8_t
2021-03-22 19:34:51 -04:00
Vy Nguyen 9670d2e4af Revert "Revert "Revert "[lld-macho] Implement -dependency_info (partially - more opcodes needed)"""
This reverts commit 5ad2c225f3.

bots still  unhappy - revertting again
2021-03-22 14:54:01 -04:00
Vy Nguyen 5ad2c225f3 Revert "Revert "[lld-macho] Implement -dependency_info (partially - more opcodes needed)""
This reverts commit 2554b95db5.

Relanding [lld-macho] Implement -dependency_info (D98559) with changes:
 - inline functions removed from cpp file.
 - updated tests to not check libSystem.tbd with other input files (because of possible indeterministic ordering)
2021-03-22 14:41:57 -04:00
Nico Weber 2554b95db5 Revert "[lld-macho] Implement -dependency_info (partially - more opcodes needed)"
This reverts commit c53a1322f3.
Test only passes depending on build dir having a lexicographically later name
than the source dir, and doesn't link on mac/win. See
https://reviews.llvm.org/D98559#2640265 onward.
2021-03-21 16:35:38 -04:00
Vy Nguyen c53a1322f3 [lld-macho] Implement -dependency_info (partially - more opcodes needed)
Bug: https://bugs.llvm.org/show_bug.cgi?id=49278
The flag is not well documented, so this implementation is based on observed behaviour.

When specified, `-dependency_info <path>` produced a text file containing information pertaining to the current linkage, such as input files, output file, linker version, etc.

This file's layout is also not documented, but it seems to be a series of null ('\0') terminated strings in the form `<op code><path>`

`<op code>` could be:
   `0x00` : linker version
   `0x10` : input
   `0x11` : files not found(??)
   `0x40` : output

`<path>` : is the file path, except for the linker-version case.

(??) This part is a bit unclear. I think it means all the files the linker attempted to look at, but could not find.

Differential Revision: https://reviews.llvm.org/D98559
2021-03-21 14:35:46 -04:00
Vy Nguyen 66f340051a [lld-macho] Define __mh_*_header synthetic symbols.
Bug: https://bugs.llvm.org/show_bug.cgi?id=49290

    Differential Revision: https://reviews.llvm.org/D97007
2021-03-19 14:14:40 -04:00
caoming.roy ed8bff13dc [lld-macho] implement options -map
Implement command-line options -map

Reviewed By: int3, #lld-macho

Differential Revision: https://reviews.llvm.org/D98323
2021-03-18 10:39:19 -04:00
Greg McGary db1e845a96 [lld-macho] Handle error cases properly for -exported_symbol(s_list)
This fixes defects in D98223 [lld-macho] implement options -(un)exported_symbol(s_list):
* disallow export of hidden symbols
* verify that whitelisted literal names are defined in the symbol table
* reflect export-status overrides in `nlist` attribute of `N_EXT` or `N_PEXT`

Thanks to @thakis for raising these issues

Differential Revision: https://reviews.llvm.org/D98381
2021-03-16 21:20:39 -07:00
Jez Ng 38a6374564 [lld-macho] Only codesign by default on arm64 macOS
instead of doing it on all arm64 platforms.

Reviewed By: #lld-macho, gkm

Differential Revision: https://reviews.llvm.org/D98446
2021-03-12 17:26:27 -05:00
Jez Ng d8283d9ddc [lld-macho][nfc] Give every SyntheticSection a fake InputSection
Previously, it was difficult to write code that handled both synthetic
and regular sections generically. We solve this problem by creating a
fake InputSection at the start of every SyntheticSection.

This refactor allows us to handle DSOHandle like a regular Defined
symbol (since Defined symbols must be attached to an InputSection), and
paves the way for supporting `__mh_*header` symbols. Additionally, it
simplifies our binding/rebase code.

I did have to extend Defined a little -- it now has a `linkerInternal`
flag, to indicate that `___dso_handle` should not be in the final symbol
table.

I've also added some additional testing for `___dso_handle`.

Reviewed By: #lld-macho, oontvoo

Differential Revision: https://reviews.llvm.org/D98545
2021-03-12 17:26:27 -05:00
Jez Ng 29bbbd06fe [lld-macho] Unbreak build breakage from rG1752f2850685 2021-03-11 13:35:13 -05:00
Jez Ng 1752f28506 [lld-macho][nfc] Remove `MachO::` prefix where possible
Previously, SyntheticSections.cpp did not have a top-level `using namespace
llvm::MachO` because it caused a naming conflict: `llvm::MachO::Symbol` would
collide with `lld::macho::Symbol`.

`MachO::Symbol` represents the symbols defined in InterfaceFiles (TBDs). By
moving the inclusion of InterfaceFile.h into our .cpp files, we can avoid this
name collision in other files where we are only dealing with LLD's own symbols.

Along the way, I removed all unnecessary "MachO::" prefixes in our code.

Cons of this approach: If TextAPI/MachO/Symbol.h gets included via some other
header file in the future, we could run into this collision again.

Alternative 1: Have either TextAPI/MachO or BinaryFormat/MachO.h use a different
namespace. Most of the benefit of `using namespace llvm::MachO` comes from being
able to use things in BinaryFormat/MachO.h conveniently; if TextAPI was under a
different (and fully-qualified) namespace like `llvm::tapi` that would solve our
problems. Cons: lots of files across llvm-project will need to be updated, and
folks who own the TextAPI code need to agree to the name change.

Alternative 2: Rename our Symbol to something like `LldSymbol`. I think this is
ugly.

Personally I think alternative #1 is ideal, but I'm not sure the effort to do it is
worthwhile, this diff's halfway solution seems good enough to me. Thoughts?

Reviewed By: #lld-macho, oontvoo, MaskRay

Differential Revision: https://reviews.llvm.org/D98149
2021-03-11 13:28:08 -05:00