Commit Graph

13765 Commits

Author SHA1 Message Date
Fangrui Song 1f69355802 [test] Make ELF tests amenable to the order of non-local symbols 2021-02-12 21:00:42 -08:00
Andy Wingo 4fc2557308 [WebAssembly][lld] Preassign table number 0 to indirect function table for MVP inputs
MVP object files may import at most one table, and if they do, it must
be assigned table number zero in the output, as the references to that
table are not relocatable.  Ensure that this is the case, even if some
inputs define other tables.

Differential Revision: https://reviews.llvm.org/D96001
2021-02-12 20:20:19 +01:00
Sam Clegg e1617d23ff Revert "[lld][WebAssembly] Fix for weak undefined functions in -pie mode"
This reverts commit ac2be2b6a3.

This causes a whole much of emscripten tests to fail due to newly
undefined symbols appearing.  Will investigate and look into re-landing
later.
2021-02-12 09:04:18 -08:00
Sam Clegg ac2be2b6a3 [lld][WebAssembly] Fix for weak undefined functions in -pie mode
This fixes two somewhat related issues.  Firstly we were never
generating imports for weak functions (even with the `import-functions`
policy for undefined symbols).  Adding a direct call to foo in the
`weak-undefined-pic.s` exposed a crash in the linker which this
change fixes.

Secondly we were failing to call `handleWeakUndefines` for the `-pie`
case which is PIC but doesn't set the undefined symbol policy to
`import-functions`.  With this change `-pie` binaries will by default
call `handleWeakUndefines` which generates the undefined stub handlers
for any weakly undefined symbols.

Fixes: https://github.com/emscripten-core/emscripten/issues/13337

Differential Revision: https://reviews.llvm.org/D95914
2021-02-11 17:16:03 -08:00
Hongtao Yu 0f848a24e1 Undo test changs introduced by D96193.
Summary:
The test doesn't work on Windows but there seems no good way to disable the test for Windows only so I'm undoing the test changes.
2021-02-11 13:29:41 -08:00
Sam Clegg 70f3c6e9e6 [lld][WebAssembly] Delay the merging of data section when dynamic linking
With dynamic linking we have the current limitation that there can be
only a single active data segment (since we use __memory_base as the
load address and we can't do arithmetic in constant expresions).

This change delays the merging of active segments until a little later
in the linking process which means that the grouping of data by section,
and the magic __start/__end symbols work as expected under dynamic
linking.

Differential Revision: https://reviews.llvm.org/D96453
2021-02-11 10:54:15 -08:00
Fangrui Song 0557b1bdec [ELF] Resolve defined symbols before undefined symbols
When parsing an object file, LLD interleaves undefined symbol resolution (which
may recursively fetch other lazy objects) with defined symbol resolution.

This may lead to surprising results, e.g. if an object file defines currently
undefined symbols and references another lazy symbol, we may interleave defined
symbols with the lazy fetch, potentially leading to the defined symbols
resolving to different files.

As an example, if both `a.a(a.o)` and `a.a(b.o)` define `foo` (not in COMDAT
group, or in different COMDAT groups) and `__profd_foo` (in COMDAT group
`__profd_foo`).  LLD may resolve `foo` to `a.a(a.o)` and `__profd_foo` to
`b.a(b.o)`, i.e. different files.

```
parse ArchiveFile a.a
  entry fetches a.a(a.o)
  parse ObjectFile a.o
    define entry
    define foo
    reference b
    b fetches a.a(b.o)
    parse ObjectFile b.o
      define prevailing __profd_foo
    define (ignored) non-prevailing __profd_foo
```

Assuming a set of interconnected symbols are defined all or none in several lazy
objects. Arguably making them resolve to the same file is preferable than making
them resolve to different files (some are lazy objects).

The main argument favoring the new behavior is the stability. The relative order
between a defined symbol and an undefined symbol does not change the symbol
resolution behavior.  Only the relative order between two undefined symbols can
affect fetching behaviors.

---

The real world case is reduced from a Fuchsia PGO usage: `a.a(a.o)` has a
constructor within COMDAT group C5 while `a.a(b.o)` has a constructor within
COMDAT group C2. Because they use different group signatures, they are not
de-duplicated. It is not entirely whether Clang behavior is entirely conforming.

LLD selects the PGO counter section (`__profd_*`) from `a.a(b.o)` and the
constructor section from `a.a(a.o)`. The `__profd_*` is a SHF_LINK_ORDER section
linking to its own non-prevailing constructor section, so LLD errors
`sh_link points to discarded section`. This patch fixes the error.

Differential Revision: https://reviews.llvm.org/D95985
2021-02-11 09:41:46 -08:00
Stella Stamenova ed98676fa4 Support multi-configuration generators correctly in several config files
Multi-configuration generators (such as Visual Studio and Xcode) allow the specification of a build flavor at build time instead of config time, so the lit configuration files need to support that - and they do for the most part. There are several places that had one of two issues (or both!):

1) Paths had %(build_mode)s set up, but then not configured, resulting in values that would not work correctly e.g. D:/llvm-build/%(build_mode)s/bin/dsymutil.exe
2) Paths did not have %(build_mode)s set up, but instead contained $(Configuration) (which is the value for Visual Studio at configuration time, for Xcode they would have had the equivalent) e.g. "D:/llvm-build/$(Configuration)/lib".

This seems to indicate that we still have a lot of fragility in the configurations, but also that a number of these paths are never used (at least on Windows) since the errors appear to have been there a while.

This patch fixes the configurations and it has been tested with Ninja and Visual Studio to generate the correct paths. We should consider removing some of these settings altogether.

Reviewed By: JDevlieghere, mehdi_amini

Differential Revision: https://reviews.llvm.org/D96427
2021-02-11 09:32:20 -08:00
Andy Wingo a56e57493b [lld][WebAssembly] Common superclass for input globals/events/tables
This commit regroups commonalities among InputGlobal, InputEvent, and
InputTable into the new InputElement.  The subclasses are defined
inline in the new InputElement.h.  NFC.

Reviewed By: sbc100

Differential Revision: https://reviews.llvm.org/D94677
2021-02-11 14:54:45 +01:00
Thomas Lively 067f005500 [lld][WebAssembly] Fix segfault in map file support
The code previously assumed that `getChunk` would return a non-null pointer for
every symbol, but in fact it only returns non-null pointers for DefinedFunction
and DefinedData symbols. This patch fixes the segfault by checking whether
`getChunk` returns a null for each symbol and skipping the mapping output for
any symbols for which it does.

Differential Revision: https://reviews.llvm.org/D88369
2021-02-09 14:42:43 -08:00
Sam Clegg 34d033ca12 [lld][WebAssembly] Allow --export of optional start/stop symbols
This moves the error checking until after all optional
symbols (including the section start/end symbols) have
been created.

Differential Revision: https://reviews.llvm.org/D96318
2021-02-09 13:14:52 -08:00
Nico Weber e0b8604e5d [lld/mac] Implement -u flag
Since we emit diagnostics for undefineds in Writer::scanRelocations()
and symbols referenced by -u flags aren't referenced by any relocations,
this needs some manual code (similar to the entry point).

Differential Revision: https://reviews.llvm.org/D94371
2021-02-09 08:23:06 -05:00
Fangrui Song d82679d805 [ELF] Drop Android specific workaround -m aarch64_elf64_le_vec
`extern const bfd_target aarch64_elf64_le_vec;` is a variable in BFD.
It was somehow misused as an emulation by Android.

```
% aarch64-linux-gnu-ld -m aarch64_elf64_le_vec a.o
aarch64-linux-gnu-ld: unrecognised emulation mode: aarch64_elf64_le_vec
Supported emulations: aarch64linux aarch64elf aarch64elf32 aarch64elf32b aarch64elfb armelf armelfb aarch64linuxb aarch64linux32 aarch64linux32b armelfb_linux_eabi armelf_linux_eabi
```

Acked by Stephen Hines, who removed the flag from Android a while back.
2021-02-09 00:43:10 -08:00
Hongtao Yu 5b8db127a3 [ELF] Rewriting the path of sample profile file for --reproduce response.txt
Rewritting the path of the sample profile file in response.txt to be relative to the repro tar.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D96193
2021-02-09 00:00:16 -08:00
Sam Clegg 88e4056b44 [lld][WebAssembly] Fix typo in function name
addOptionalGlobalSymbols should be addOptionalGlobalSymbol.

Also, remove unnecessary additional argument to make the signature match
the sibling function: addOptionalDataSymbol.

Differential Revision: https://reviews.llvm.org/D96305
2021-02-08 19:41:01 -08:00
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
Fangrui Song 830ead58fe [test] Fix unused check prefixes 2021-02-08 13:44:30 -08:00
Jez Ng ac9dd247da [lld-macho] Try to make ubsan happy
Summary: We should avoid passing a null pointer to memcpy.
2021-02-08 14:51:36 -05:00
Jez Ng 5112035751 [lld-macho] Emit LSDA info in compact unwind
The LSDA pointers are encoded as offsets from the image base,
and arranged in one big contiguous array. Each second-level page records
the offset within that LSDA array which corresponds to the LSDA for its
first CU entry.

Reviewed By: clayborg

Differential Revision: https://reviews.llvm.org/D95810
2021-02-08 13:48:00 -05:00
Jez Ng 525bfa10ec [lld-macho] Emit personalities in compact unwind
Note that there is a triple indirection involved with
personalities and compact unwind:

1. Two bits of each CU encoding are used as an offset into the
   personality array.
2. Each entry of the personality array is an offset from the image base.
   The resulting address (after adding the image base) should point within the
   GOT.
3. The corresponding GOT entry contains the actual pointer to the
   personality function.

To further complicate things, when the personality function is in the
object file (as opposed to a dylib), its references in
`__compact_unwind` may refer to it via a section + offset relocation
instead of a symbol relocation. Since our GOT implementation can only
create entries for symbols, we have to create a synthetic symbol at the
given section offset.

Reviewed By: clayborg

Differential Revision: https://reviews.llvm.org/D95809
2021-02-08 13:47:59 -05:00
Fangrui Song eea34aae2e [ELF] Inspect -EL & -EB for OUTPUT_FORMAT(default, big, little)
Choose big if -EB is specified, little if -EL is specified, or default if neither is specified.
The new behavior matches GNU ld.

Fixes: https://github.com/ClangBuiltLinux/linux/issues/1025

Differential Revision: https://reviews.llvm.org/D96214
2021-02-08 10:34:57 -08:00
Fangrui Song 7605a9a009 [ELF] Support aarch64_be
This patch adds

* Big-endian values for `R_AARCH64_{ABS,PREL}{16,32,64}` and `R_AARCH64_PLT32`
* aarch64elfb & aarch64linuxb BFD emulations
* elf64-bigaarch64 output format (bfdname)

Link: https://github.com/ClangBuiltLinux/linux/issues/1288

Differential Revision: https://reviews.llvm.org/D96188
2021-02-08 08:55:29 -08:00
Fangrui Song 980d28d955 ELFObjectWriter: Don't sort local symbols
GNU as does not sort local symbols. This has several advantages:

* The .symtab order is roughly the symbol occurrence order.
* The closest preceding STT_SECTION symbol is the definition of a local symbol.
* The closest preceding STT_FILE symbol is the defining file of a local symbol, if there are multiple default-version .file directives. (Not implemented in MC.)
2021-02-07 15:47:10 -08:00
Fangrui Song 4b5dbc7a3b [ELF][test] Improve aarch64 tests 2021-02-06 11:50:57 -08:00
Fangrui Song 6a1235211d [ELF] --gc-sections: collect unused SHF_LINK_ORDER .gcc_except_table
A SHF_LINK_ORDER .gcc_except_table is similar to a .gcc_except_table in
a section group. The associated text section is responsible for retaining it.

LLD still does not support GC of non-group non-SHF_LINK_ORDER .gcc_except_table -
but that is not necessary because we can teach the compiler to set SHF_LINK_ORDER.
2021-02-05 21:35:27 -08:00
Greg McGary c3e4f3b231 [lld-macho] Fix alignment & layout to match ld64 and satisfy kernel & codesign
The Mach kernel & codesign on arm64 macOS has strict requirements for alignment and sequence of segments and sections. Dyld probably is just as picky, though kernel & codesign reject malformed Mach-O files before dyld ever has a chance.

I developed this diff by incrementally changing alignments & sequences to match the output of ld64. I stopped when my hello-world test program started working: `codesign --verify` succeded, and `execve(2)` didn't immediately fail with `errno == EBADMACHO` = `"Malformed Mach-O file"`.

Differential Revision: https://reviews.llvm.org/D94935
2021-02-05 17:22:03 -07:00
Fangrui Song 5f4d7b2f0a [ELF] Improve --icf=safe diagnostic
The current diagnostic has confused users. The new wording is adapted from one suggested by Ian Lance Taylor.

Differential Revision: https://reviews.llvm.org/D95917
2021-02-05 09:37:37 -08:00
Fangrui Song ed399d508f [ELF] Make SHF_GNU_RETAIN sections GC roots
binutils 2.36 introduced the new section flag SHF_GNU_RETAIN (for ELFOSABI_GNU &
ELFOSABI_FREEBSD) to mark a sections as a GC root. Several LLVM side toolchain
folks (including me) were involved in the design process of SHF_GNU_RETAIN and
were happy with this proposal.

Currently GNU ld only respects SHF_GNU_RETAIN semantics for ELFOSABI_GNU &
ELFOSABI_FREEBSD object files
(https://sourceware.org/bugzilla/show_bug.cgi?id=27282).  GNU ld sets EI_OSABI
to ELFOSABI_GNU for relocatable output
(https://sourceware.org/bugzilla/show_bug.cgi?id=27091). In practice the single
value EI_OSABI is neither a good indicator for object file compatibility, nor a
useful mechanism marking used ELF extensions.

For input, we respect SHF_GNU_RETAIN semantics even for ELFOSABI_NONE object
files. This is compatible with how LLD and GNU ld handle (mildly useful) STT_GNU_IFUNC
/ (emitted by GCC, considered misfeature by some folks) STB_GNU_UNIQUE input.
(As of LLVM 12.0.0, the integrated assembler does not set ELFOSABI_GNU for
STT_GNU_IFUNC/STB_GNU_UNIQUE).
Arguably STT_GNU_IFUNC/STB_GNU_UNIQUE probably need indicators in object files
but SHF_GNU_RETAIN is more likely accepted by more OSABI platforms.

For output, we take a step further than GNU ld: we don't promote ELFOSABI_NONE
to ELFOSABI_GNU for all output.

Differential Revision: https://reviews.llvm.org/D95749
2021-02-04 09:23:01 -08:00
Fangrui Song b3165a70ae [ELF] Allow R_386_GOTOFF from .debug_info
In GCC emitted .debug_info sections, R_386_GOTOFF may be used to
relocate DW_AT_GNU_call_site_value values
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98946).

R_386_GOTOFF (`S + A - GOT`) is one of the `isStaticLinkTimeConstant` relocation
type which is not PC-relative, so it can be used from non-SHF_ALLOC sections. We
current allow new relocation types as needs come. The diagnostic has caught some
bugs in the past.

Differential Revision: https://reviews.llvm.org/D95994
2021-02-04 09:17:47 -08:00
Jez Ng ea5b75de49 [lld-macho] Try to fix Windows build 2021-02-03 16:05:23 -05:00
Jez Ng 2d2e0000d3 [lld-macho] Rename VERSION CONTROL to VERSION TARGETING in helptext
Per https://reviews.llvm.org/D94938#inline-896740.
2021-02-03 13:43:47 -05:00
Jez Ng 4b2169fb6b [lld-macho] Remove stray ehFrame change
Per https://reviews.llvm.org/D95121#inline-897943.
2021-02-03 13:43:47 -05:00
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 163dcd8513 [lld-macho] Associate each Symbol with an InputFile
This makes our error messages more informative. But the bigger motivation is for
LTO symbol resolution, which will be in an upcoming diff. The changes in this
one are largely mechanical.

Reviewed By: #lld-macho, smeenai

Differential Revision: https://reviews.llvm.org/D94316
2021-02-03 13:43:47 -05:00
Abhina Sreeskantharajan e59d336e75 [test] Use host platform specific error message substitution in lit tests - continued
On z/OS, other error messages are not matched correctly in lit tests.

```
EDC5121I Invalid argument.
EDC5111I Permission denied.
```

This patch adds a lit substitution to fix it.

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D95808
2021-02-03 09:53:22 -05:00
Greg McGary 3a9d2f1488 [lld-macho][NFC] refactor relocation handling
Add per-reloc-type attribute bits and migrate code from per-target file into target independent code, driven by reloc attributes.

Many cleanups

Differential Revision: https://reviews.llvm.org/D95121
2021-02-02 10:54:53 -07:00
Fangrui Song 57bfa2ddb6 [ELF] Delete unused --warn-ifunc-textrel
The option catches incompatibility between `R_*_IRELATIVE` and DT_TEXTREL/DF_TEXTREL
before glibc 2.29. Newer glibc versions are more common nowadays and I don't
think this option has ever been used. Diagnosing this problem is also
straightforward by reading the stack trace.
2021-02-02 09:47:06 -08:00
Fangrui Song 3f8dda50cb [test] Fix unuses FileCheck prefixes in lld 2021-02-01 20:52:33 -08:00
Wouter van Oortmerssen 0d9b17d0ef [WebAssembly] fixed wasm64 data segment init exp not 64-bit
As defined in the spec:
https://github.com/WebAssembly/memory64/blob/master/proposals/memory64/Overview.md

Differential Revision: https://reviews.llvm.org/D95651
2021-02-01 11:32:50 -08:00
Fangrui Song 3949a3ed49 [ELF][test] Add --emit-relocs --gc-sections test for relocation section for a non-SHF_ALLOC section
This has been fixed by D89841.
2021-01-30 00:51:36 -08:00
Greg McGary 0ef25cf558 [lld-macho][NFC] Add new option group for versions
Coalesce all version control options into a group

Differential Revision: https://reviews.llvm.org/D94938
2021-01-29 22:27:41 -07:00
Christopher Tetreault d3e8b9fdc0 Revert "[CMake] Actually require python 3.6 or greater"
There are builders that do not have python 3.6. Revert until this situation can be rectified

This reverts commit 0703b0753c.
2021-01-29 12:03:32 -08:00
Christopher Tetreault 0703b0753c [CMake] Actually require python 3.6 or greater
Previously, CMake would find any version of Python3. However, the project
claims to require 3.6 or greater, and 3.6 features are being used.

Reviewed By: yln

Differential Revision: https://reviews.llvm.org/D95635
2021-01-29 11:47:21 -08:00
Abhina Sreeskantharajan 42a21778f6 [test] Use host platform specific error message substitution in lit tests
On z/OS, the following error message is not matched correctly in lit tests.

```
EDC5129I No such file or directory.
```

This patch uses a lit config substitution to check for platform specific error messages.

Reviewed By: muiez, jhenderson

Differential Revision: https://reviews.llvm.org/D95246
2021-01-29 07:16:30 -05:00
Reid Kleckner bacf9cf2c5 Revert "[PDB] Defer relocating .debug$S until commit time and parallelize it"
This reverts commit 1a9bd5b813.

I suspect that this patch may have caused https://crbug.com/1171438.
2021-01-28 13:17:27 -08:00
Sam Clegg 5c0164890c [lld][WebAssembly] Update comments mentioning legacy function names. NFC
The __wasm_apply_relocs function was split into two separate
functions as part of https://reviews.llvm.org/D93066 but these
comments were not correctly updated at the time.

Differential Revision: https://reviews.llvm.org/D95623
2021-01-28 08:52:14 -08:00
Teresa Johnson 1487747e99 [LTO] Prevent devirtualization for symbols dynamically exported
Identify dynamically exported symbols (--export-dynamic[-symbol=],
--dynamic-list=, or definitions needed to preempt shared objects) and
prevent their LTO visibility from being upgraded.
This helps avoid use of whole program devirtualization when there may
be overrides in dynamic libraries.

Differential Revision: https://reviews.llvm.org/D91583
2021-01-27 15:54:13 -08:00
Tom Stellard 5369517d20 Bump the trunk major version to 13
and clear the release notes.
2021-01-26 19:37:55 -08:00
Adhemerval Zanella 988cc0a083 [LLD][ELF][AArch64] Add support for R_AARCH64_LD64_GOTPAGE_LO15 relocation
It is not used by LLVM, but GCC might generates it when compiling
with -fpie, as indicated by PR#40357 [1].

[1] https://bugs.llvm.org/show_bug.cgi?id=40357
2021-01-26 12:01:38 +00:00
Georgii Rymar e98d5c3192 [libObject,llvm-readelf/obj] - Don't use @@ when printing versions of undefined symbols.
A default version (@@) is only available for defined symbols.

Currently we use "@@" for undefined symbols too.
This patch fixes the issue and improves our test case.

Differential revision: https://reviews.llvm.org/D95219
2021-01-26 12:05:59 +03:00