Commit Graph

12874 Commits

Author SHA1 Message Date
Fangrui Song 26e6880434 [ELF][test] Reorganize warn-backrefs.s 2020-04-05 10:28:32 -07:00
Fangrui Song 9195b01911 [ELF][PPC64] Enable R_PPC64_REL14 trunks
The thunk implementation is available but an assertion disallows it.
Linux kernel has such a use case: in arch/powerpc/kernel/exceptions-64s.S:handle_page_fault,
beq+ ret_from_except_lite may get out of range.

Link: https://github.com/ClangBuiltLinux/linux/issues/951

Differential Revision: https://reviews.llvm.org/D76904
2020-04-04 10:59:17 -07:00
Fangrui Song a13212582a [ELF][test] Test that thunks are processed before finalizeSynthetic(in.symTab)
finalizeSynthetic(in.symTab) calls sortSymTabSymbols() to order local
symbols before non-local symbols.

The newly added tests ensure that thunk symbols are added before
finalizeSynthetic(in.symTab), otherwise .symtab would be out of order.
2020-04-04 10:57:37 -07:00
Nico Weber eb81d440fc fix typo in comment to cycle bots 2020-04-04 12:52:45 -04:00
Fangrui Song 56decd982d [ELF] Allow invalid sh_size%sh_entsize!=0 for non-SHF_MERGE sections
Fixes https://bugs.llvm.org/show_bug.cgi?id=45370
Fixes https://github.com/Clozure/ccl/issues/273

.stab holds a table of 12-byte entries. GNU as before 2.35 incorrectly
sets sh_entsize(.stab) to 20 on 64-bit architectures:
https://sourceware.org/bugzilla/show_bug.cgi?id=25768

We should not emit the confusing error:
"SHF_MERGE section size (...) must be a multiple of sh_entsize (20)

Reviewed By: grimar, psmith

Differential Revision: https://reviews.llvm.org/D77368
2020-04-03 08:48:30 -07:00
Sid Manning c484b3e334 [Hexagon] Fix issue with non-preemptible STT_TLS symbols
A PC-relative relocation referencing a non-preemptible absolute symbol
(due to STT_TLS) is not representable in -pie/-shared mode.

Differential Revision: https://reviews.llvm.org/D77021
2020-04-03 08:55:23 -05:00
Benjamin Kramer 02cb21df3f Make helpers static. NFC. 2020-04-03 12:48:25 +02:00
Peter Smith da74537e87 [LLD][ELF][ARM] use .reloc directive for Thumb assembler tests
In the near future llvm-mc will resolve the fixups that generate
R_ARM_THUMB_PC8 and R_ARM_THUMB_PC12 at assembly time (see comments in
D72892), and forbid inter-section references. Change the LLD tests for
these relocations to use .inst and .reloc to avoid LLD tests failing when
this happens. The tests generate the same instructions, relocations
and symbols.

I will need to make equivalent changes for D75349 Arm equivalent
relocations, but this is still in review so these don't need changing
before llvm-mc.

Differential Revision: https://reviews.llvm.org/D77200
2020-04-03 11:44:31 +01:00
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
Fangrui Song 42bb5cc502 [ELF] Change some "Alias for " help messages to use double dashed options
The aliased options in the --help output use double dashes. It is
inconsistent to have single-dashed messages. Additionally, -l and -t are
common short options and single-dashed forms prefixed with them can
cause confusion.
2020-04-02 09:27:56 -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
Fangrui Song 85adce3d73 [PPCInstPrinter] Change B to print the target address in hexadecimal form
Follow-up of D76591 and D76907
2020-04-01 22:38:24 -07:00
Igor Kudrin b0b1f451ae [LLD][ELF] Follow the common pattern in a message about an undefined vtable symbol.
In most cases, LLD prints its multiline diagnostic messages starting
additional lines with ">>> ". That greatly helps external tools to parse
the output, simplifying combining several lines of the log back into one
message. The patch fixes the only message I found that does not follow
the common pattern.

Differential Revision: https://reviews.llvm.org/D77132
2020-04-02 11:39:03 +07:00
Kazuaki Ishizaki 7c5fcb3591 [lld] NFC: fix trivial typos in comments
Differential Revision: https://reviews.llvm.org/D72339
2020-04-02 01:21:36 +09:00
Fangrui Song bb4a36ea28 [ELF] Propagate LMA offset to sections with neither AT() nor AT>
Fixes https://bugs.llvm.org/show_bug.cgi?id=45313
Also fixes linkerscript/{at4.s,overlay.test} LMA address issues exposed by
011b785505.
Related: D74297

This patch improves emulation of GNU ld's heuristics on the difference
between the LMA and the VMA:
https://sourceware.org/binutils/docs/ld/Output-Section-LMA.html#Output-Section-LMA

New test linkerscript/lma-offset.s (based on at4.s) demonstrates some behaviors.

Reviewed By: psmith

Differential Revision: https://reviews.llvm.org/D76995
2020-04-01 08:19:06 -07:00
Fangrui Song f2036a15d3 [ELF] Print symbols with non-default versions for better "undefined symbol" diagnostics
When reporting an "undefined symbol" diagnostic:

* We don't print @ for the reference.
* We don't print @ or @@ for the definition. https://bugs.llvm.org/show_bug.cgi?id=45318

This can lead to confusing diagnostics:

```
// foo may be foo@v2
ld.lld: error: undefined symbol: foo
>>> referenced by t1.o:(.text+0x1)
// foo may be foo@v1 or foo@@v1
>>> did you mean: foo
>>> defined in: t.so
```

There are 2 ways a symbol in symtab may get truncated:

* A @@ definition may be truncated *early* by SymbolTable::insert().
  The name ends with a '\0'.
* A @ definition/reference may be truncated *later* by Symbol::parseSymbolVersion().
  The name ends with a '@'.

This patch detects the second case and improves the diagnostics. The first case is
not improved but the second case is sufficient to make diagnostics not confusing.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D76999
2020-04-01 08:04:36 -07:00
scentini 51d594d33c Replace output file name in test with %t 2020-04-01 16:40:02 +02:00
Sam Clegg b5767010a8 [lld][WebAssembly] Early error if output file cannot be created.
This matches the behaviour of the ELF driver.

Also move the `createFiles` to be `checkConfig` and report `no input
files` there.   Again this is mostly to match the structure of the ELF
linker better.

Differential Revision: https://reviews.llvm.org/D76960
2020-03-31 21:42:38 -07:00
Fangrui Song 0f44a09757 [ELF][test] Add 'REQUIRES: x86' to threads.s 2020-03-31 15:25:01 -07:00
Fangrui Song 4af7560b37 [PPCInstPrinter] Print conditional branches as `bt 2, $target` instead of `bt 2, .+$imm`
Follow-up of D76591.

Reviewed By: #powerpc, sfertile

Differential Revision: https://reviews.llvm.org/D76907
2020-03-31 15:05:38 -07:00
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
Fangrui Song eb4663d8c6 [lld][COFF][ELF][WebAssembly] Replace --[no-]threads /threads[:no] with --threads={1,2,...} /threads:{1,2,...}
--no-threads is a name copied from gold.
gold has --no-thread, --thread-count and several other --thread-count-*.

There are needs to customize the number of threads (running several lld
processes concurrently or customizing the number of LTO threads).
Having a single --threads=N is a straightforward replacement of gold's
--no-threads + --thread-count.

--no-threads is used rarely. So just delete --no-threads instead of
keeping it for compatibility for a while.

If --threads= is specified (ELF,wasm; COFF /threads: is similar),
--thinlto-jobs= defaults to --threads=,
otherwise all available hardware threads are used.

There is currently no way to override a --threads={1,2,...}. It is still
a debate whether we should use --threads=all.

Reviewed By: rnk, aganea

Differential Revision: https://reviews.llvm.org/D76885
2020-03-31 08:46:12 -07:00
Peter Smith 2539b4ae47 [LLD][ELF] Allow empty (.init|.preinit|.fini)_array to be RELRO
The default GNU linker script uses the following idiom for the array
sections. I'll use .init_array here, but this also applies to
.preinit_array and .fini_array sections.

  .init_array    :
  {
    PROVIDE_HIDDEN (__init_array_start = .);
    KEEP (*(.init_array))
    PROVIDE_HIDDEN (__init_array_end = .);
  }

The C-library will take references to the _start and _end symbols to
process the array. This will make LLD keep the OutputSection even if there
are no .init_array sections. As the current check for RELRO uses the
section type for .init_array the above example with no .init_array
InputSections fails the checks as there are no .init_array sections to give
the OutputSection a type of SHT_INIT_ARRAY. This often leads to a
non-contiguous RELRO error message.

The simple fix is to a textual section match as well as a section type
match.

Differential Revision: https://reviews.llvm.org/D76915
2020-03-31 12:53:12 +01:00
James Henderson b4d0384a6c [ELF][test] Add test for --gc-sections + many sections
This test covers the case where --gc-sections is used when there are
many sections. In particular, it ensures that there is no adverse
interaction with common and absolute symbols.

Reviewed by: MaskRay, grimar

Differential Revision: https://reviews.llvm.org/D76003
2020-03-31 12:41:19 +01:00
James Henderson 0aa9c5429b [lld][ELF][test] Improve deplib.s
The test had a few style issues, and I noticed a hole in the coverage
(namely that the search order wasn't tested). Adding cases for the hole
in turn meant other cases weren't important.

The .so test case isn't important, since the code is shared code, so
I've removed it. Additionally, I've modified the usage of the "bar"
directive to show that an unneeded library must still be present, or the
link will fail, even though it isn't linked in.

Reviewed by: MaskRay, grimar

Differential Revision: https://reviews.llvm.org/D76851
2020-03-31 12:41:18 +01:00
Kai Wang 581ba35291 [RISCV] ELF attribute section for RISC-V.
Leverage ARM ELF build attribute section to create ELF attribute section
for RISC-V. Extract the common part of parsing logic for this section
into ELFAttributeParser.[cpp|h] and ELFAttributes.[cpp|h].

Differential Revision: https://reviews.llvm.org/D74023
2020-03-31 16:16:19 +08:00
Fangrui Song 51475e4023 [ELF][test] Add linkerscript/linkorder-linked-to.s
Delete relocatable-linkorder.s which is covered.
2020-03-30 15:17:29 -07:00
Nico Weber 20eb719f99 lld: Reduce number of references to undefined printed from 10 to 3.
As of a while ago, lld groups all undefined references to a single
symbol in a single diagnostic. Back then, I made it so that we
print up to 10 references to each undefined symbol.

Having used this for a while, I never wished there were more
references, but I sometimes found that this can print a lot of
output. lld prints up to 10 diagnostics by default, and if
each has 10 references (which I've seen in practice), and each
undefined symbol produces 2 (possibly very long) lines of output,
that's over 200 lines of error output.

Let's try it with just 3 references for a while and see how
that feels in practice.

Differential Revision: https://reviews.llvm.org/D77017
2020-03-30 14:31:32 -04:00
Fangrui Song 673e81eee4 [ELF] Allow SHF_LINK_ORDER and non-SHF_LINK_ORDER to be mixed
Currently, `error: incompatible section flags for .rodata` is reported
when we mix SHF_LINK_ORDER and non-SHF_LINK_ORDER sections in an output section.

This is overconstrained. This patch allows mixed flags with the
requirement that SHF_LINK_ORDER sections must be contiguous. Mixing
flags is used by Linux aarch64 (https://github.com/ClangBuiltLinux/linux/issues/953)

  .init.data : { ... KEEP(*(__patchable_function_entries)) ... }

When the integrated assembler is enabled, clang's -fpatchable-function-entry=N[,M]
implementation sets the SHF_LINK_ORDER flag (D72215) to fix a number of
garbage collection issues.

Strictly speaking, the ELF specification does not require contiguous
SHF_LINK_ORDER sections but for many current uses of SHF_LINK_ORDER like
.ARM.exidx/__patchable_function_entries there has been a requirement for
the sections to be contiguous on top of the requirements of the ELF
specification.

This patch also imposes one restriction: SHF_LINK_ORDER sections cannot
be separated by a symbol assignment or a BYTE command. Not allowing BYTE
is a natural extension that a non-SHF_LINK_ORDER cannot be a separator.
Symbol assignments can delimiter the contents of SHF_LINK_ORDER
sections.  Allowing SHF_LINK_ORDER sections across symbol assignments
(especially __start_/__stop_) can make things hard to explain. The
restriction should not be a problem for practical use cases.

Reviewed By: psmith

Differential Revision: https://reviews.llvm.org/D77007
2020-03-30 10:03:55 -07:00
Fangrui Song 2d19270efc [ELF][test] Improve linkerscript/linkorder.s 2020-03-30 09:34:29 -07:00
Alexandre Ganea 42dc667db2 [LLD][ELF] Put back rounding which was lost in 8404aeb56a 2020-03-29 21:52:01 -04:00
Fangrui Song 00c76f3496 [ELF][test] Improve arm-exidx-output.s to test different output text sections
Delete arm-exidx-link.s which is now covered by arm-exidx-output.s

Differential Revision: https://reviews.llvm.org/D76409
2020-03-29 13:12:20 -07:00
Benjamin Kramer b578f130a7 [COFF] Stabilize sort
Found by llvm::sort's expensive checks.
2020-03-28 21:38:50 +01:00
Matt Schulte fdc41aa22c [lld][ELF] Mark empty NOLOAD output sections SHT_NOBITS instead of SHT_PROGBITS
This fixes PR# 45336.
Output sections described in a linker script as NOLOAD with no input sections would be marked as SHT_PROGBITS.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D76981
2020-03-28 10:07:58 -07:00
Thomas Preud'homme 6eb345af5a [lld test] Tighten ELF/pre_init_fini_array.s test
Summary:
Make use of FileCheck numeric variable to tighten symbol address checks
in ELF/pre_init_fini_array.s test.

Reviewers: khemant, compnerd, echristo, jhenderson, espindola, MaskRay

Reviewed By: MaskRay

Subscribers: emaste, MaskRay, llvm-commits, rupprecht

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D76852
2020-03-27 21:44:12 +00:00
Reid Kleckner c579a5b1d9 [COFF] Don't treat DWARF sections as GC roots
DWARF sections are typically live and not COMDAT, so they would be
treated as GC roots. Enabling DWARF would essentially keep all code with
debug info alive, preventing any section GC.

Fixes PR45273

Reviewed By: mstorsjo, MaskRay

Differential Revision: https://reviews.llvm.org/D76935
2020-03-27 12:37:43 -07:00
Fangrui Song 34bdddf9a1 [ELF][test] Split basic.s 2020-03-27 11:56:02 -07:00
Alexandre Ganea 09158252f7 [ThinLTO] Allow usage of all hardware threads in the system
Before this patch, it wasn't possible to extend the ThinLTO threads to all SMT/CMT threads in the system. Only one thread per core was allowed, instructed by usage of llvm::heavyweight_hardware_concurrency() in the ThinLTO code. Any number passed to the LLD flag /opt:lldltojobs=..., or any other ThinLTO-specific flag, was previously interpreted in the context of llvm::heavyweight_hardware_concurrency(), which means SMT disabled.

One can now say in LLD:
/opt:lldltojobs=0 -- Use one std::thread / hardware core in the system (no SMT). Default value if flag not specified.
/opt:lldltojobs=N -- Limit usage to N threads, regardless of usage of heavyweight_hardware_concurrency().
/opt:lldltojobs=all -- Use all hardware threads in the system. Equivalent to /opt:lldltojobs=$(nproc) on Linux and /opt:lldltojobs=%NUMBER_OF_PROCESSORS% on Windows. When an affinity mask is set for the process, threads will be created only for the cores selected by the mask.

When N > number-of-hardware-threads-in-the-system, the threads in the thread pool will be dispatched equally on all CPU sockets (tested only on Windows).
When N <= number-of-hardware-threads-on-a-CPU-socket, the threads will remain on the CPU socket where the process started (only on Windows).

Differential Revision: https://reviews.llvm.org/D75153
2020-03-27 10:20:58 -04:00
Dan Gohman 66bfbedbdf [WebAssembly] Support wasm exports with zero-length names.
Zero-length strings are valid export names in WebAssembly, so allow
users to specify them.

Differential Revision: https://reviews.llvm.org/D71793
2020-03-26 16:20:43 -07:00
Paolo Severini aff75e1a1f [lld][Wasm] Wasm-ld emits invalid .debug_ranges entries for non-live symbols
When the debug info contains a relocation against a dead symbol, wasm-ld
may emit spurious range-list terminator entries (entries with Start==0
and End==0). This change fixes this by emitting the WasmRelocation
Addend as End value for a non-live symbol.

Reviewed by: sbc100, dblaikie

Differential Revision: https://reviews.llvm.org/D74781
2020-03-26 14:26:31 -07:00
Heejin Ahn f033f201a7 [WebAssembly] Add test for event section order change
Summary:
This adds a test for D76752. Now the global section comes after the
event section, and this change makes sure it is satisfied.

Reviewers: sbc100, tlively

Reviewed By: tlively

Subscribers: dschuff, jgravelle-google, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D76823
2020-03-26 11:05:24 -07:00
Fangrui Song 3eef47407b [PPCInstPrinter] Change printBranchOperand(calltarget) to print the target address in hexadecimal form
```
// llvm-objdump -d output (before)
0: bl .-4
4: bl .+0
8: bl .+4

// llvm-objdump -d output (after) ; GNU objdump -d
0: bl 0xfffffffc / bl 0xfffffffffffffffc
4: bl 0x4
8: bl 0xc
```

Many Operand's are not annotated as OPERAND_PCREL.
They are not affected (e.g. `b .+67108860`). I plan to fix them in future patches.

Modified test/tools/llvm-objdump/ELF/PowerPC/branch-offset.s to test
address space wraparound for powerpc32 and powerpc64.

Reviewed By: sfertile, jhenderson

Differential Revision: https://reviews.llvm.org/D76591
2020-03-26 08:32:29 -07:00
James Henderson 3ff3c6986b [lld][ELF] Fix error message
The error previously talked about a "section header" but was actually
referring to a program header.

Reviewed by: grimar, MaskRay

Differential Revision: https://reviews.llvm.org/D76846
2020-03-26 15:30:24 +00:00
Fangrui Song 87de9a0786 [X86InstPrinter] Change printPCRelImm to print the target address in hexadecimal form
```
// llvm-objdump -d output (before)
400000: e8 0b 00 00 00   callq 11
400005: e8 0b 00 00 00   callq 11

// llvm-objdump -d output (after)
400000: e8 0b 00 00 00  callq 0x400010
400005: e8 0b 00 00 00  callq 0x400015

// GNU objdump -d. The lack of 0x is not ideal because the result cannot be re-assembled
400000: e8 0b 00 00 00  callq 400010
400005: e8 0b 00 00 00  callq 400015
```

In llvm-objdump, we pass the address of the next MCInst. Ideally we
should just thread the address of the current address, unfortunately we
cannot call X86MCCodeEmitter::encodeInstruction (X86MCCodeEmitter
requires MCInstrInfo and MCContext) to get the length of the MCInst.

MCInstPrinter::printInst has other callers (e.g llvm-mc -filetype=asm, llvm-mca) which set Address to 0.
They leave MCInstPrinter::PrintBranchImmAsAddress as false and this change is a no-op for them.

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D76580
2020-03-26 08:28:59 -07:00
Fangrui Song 72ffc14e13 [ELF][test] Delete unneeded binding directive (.weak or .globl)
Future MC may error for a changed symbol binding.
This may be a preferred resolution to https://bugs.llvm.org/show_bug.cgi?id=38921

See https://sourceware.org/pipermail/binutils/2020-March/110399.html
2020-03-25 23:34:46 -07:00
Heejin Ahn f93426c5b9 [WebAssembly] Move event section before global section
Summary:
https://github.com/WebAssembly/exception-handling/issues/98

Also this moves many parts of code to make code align with the section
order, even if they don't affect the output.

Reviewers: tlively

Subscribers: dschuff, sbc100, hiraditya, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D76752
2020-03-25 11:49:03 -07:00
Sylvain Audi b91905a263 [lld-link] Support /map option, matching link.exe 's /map output format
Added support for /map and /map:[filepath].
The output was derived from Microsoft's Link.exe output when using that same option.
Note that /MAPINFO support was not added.

The previous implementation of MapFile.cpp/.h was meant for /lldmap, and was renamed to LLDMapFile.cpp/.h
MapFile.cpp/.h is now for /MAP
However, a small fix was added to lldmap, replacing a std::sort with std::stable_sort to enforce reproducibility.

Differential Revision: https://reviews.llvm.org/D70557
2020-03-24 09:48:00 -04:00
Eli Friedman f301806851 [lld] Enabling loading LLVM pass plugins
Add the relevant magic bits to allow "-mllvm=-load=plugin.so" etc.

This is now using export_executable_symbols_for_plugins, so symbols are
only exported if plugins are enabled.

Differential Revision: https://reviews.llvm.org/D75879
2020-03-23 14:18:32 -07:00
Fangrui Song 9e33c09647 [ELF] Keep orphan section names (.rodata.foo .text.foo) unchanged if !hasSectionsCommand
This behavior matches GNU ld and seems reasonable.

```
// If a SECTIONS command is not specified
.text.* -> .text
.rodata.* -> .rodata
.init_array.* -> .init_array
```

A proposed Linux feature CONFIG_FG_KASLR may depend on the GNU ld behavior.

Reword a comment about -z keep-text-section-prefix and a comment about
CommonSection (deleted by rL286234).

Reviewed By: grimar

Differential Revision: https://reviews.llvm.org/D75225
2020-03-23 10:30:06 -07:00
Fangrui Song 0a076f2660 [ELF][test] Clean text-section-prefix.s 2020-03-23 09:38:59 -07:00