Commit Graph

12476 Commits

Author SHA1 Message Date
Reid Kleckner 0291d30929 [COFF] Add null check in case of symbols defined in LTO blobs
The test case could probably be improved further if the failure path was
better understood.

Fixes PR42536

llvm-svn: 365979
2019-07-13 00:20:34 +00:00
Thomas Lively 26a6b95da9 [WebAssembly] i32.const operands should be signed
Summary:
This was causing large addresses to be emitted as negative numbers,
which rightfully caused crashes in binaryen.

Reviewers: aheejin, dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64612

llvm-svn: 365930
2019-07-12 17:55:07 +00:00
Rui Ueyama 332fc712c6 Fix odd variable names.
llvm-svn: 365875
2019-07-12 06:12:27 +00:00
Simon Atanasyan 5dd5541d9f [mips] Simplify test case. NFC
Before rL295040 the linker just crashed when a GOT relocation (R_MIPS_GOT16)
comes from a merge section. To ensure that this bug still fixed it's enough
to check that the linker does not crash and create GOT entries.

llvm-svn: 365834
2019-07-11 21:55:56 +00:00
Martin Storsjo 6bd26db06a [COFF] Share the tail in delayimport symbol thunks
E.g. for x86_64, previously each symbol's thunk was 87 bytes. Now
there's a 12 byte thunk per symbol, plus a shared 83 byte tail
function.

This is similar to what both MS link.exe and GNU tools do for
delay imports.

Differential Revision: https://reviews.llvm.org/D64288

llvm-svn: 365823
2019-07-11 21:19:11 +00:00
Bob Haarman 5011b83237 [lld-link] implement -thinlto-{prefix,object-suffix}-replace
Summary:
Adds the following two options to lld-link:

-thinlto-prefix-replace: allows replacing a prefix in paths generated
for ThinLTO. This can be used to ensure index files and native object
files are stored in unique directories, allowing multiple distributed
ThinLTO links to proceed concurrently.

-thinlto-object-suffix-replace: allows replacing a suffix in object
file paths involved in ThinLTO. This allows minimized index files to
be used for the thin link while storing the paths to the full bitcode
files for subsequent steps (code generation and final linking).

Reviewers: ruiu, tejohnson, pcc, rnk

Subscribers: mehdi_amini, steven_wu, dexonsmith, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64542

llvm-svn: 365807
2019-07-11 18:48:58 +00:00
Bob Haarman 63efb28f47 [lld-link] implement -thinlto-index-only
Summary:
This implements -thinlto-index-only, -thinlto-index-only:,
and -thinlto-emit-imports-files options in lld-link. They are
analogous to their counterparts in ld.lld: -thinlto-index-only
causes us to perform ThinLTO's thin link and write index files,
but not perform code generation. -thinlto-index-only: does the
same, but also writes a text file listing the native object
files expected to be generated. -thinlto-emit-imports-files
creates a text file next to each index file, listing the files
to import from.

Reviewers: ruiu, tejohnson, pcc, rnk

Subscribers: mehdi_amini, steven_wu, dexonsmith, arphaman, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64461

llvm-svn: 365800
2019-07-11 18:03:14 +00:00
Sam Clegg fd11ce32bb [WebAssembly] Import __stack_pointer when building -pie binaries
The -pie binary doesn't know that layout ahead of time so needs to
import the stack pointer from the embedder, just like we do already
for shared libraries.

This change is needed in order to address:
https://github.com/emscripten-core/emscripten/issues/8915

Differential Revision: https://reviews.llvm.org/D64516

llvm-svn: 365771
2019-07-11 13:13:25 +00:00
Fangrui Song e1ee3837ac [ELF] Handle non-glob patterns before glob patterns in version scripts & fix a corner case of --dynamic-list
This fixes PR38549, which is silently accepted by ld.bfd.
This seems correct because it makes sense to let non-glob patterns take
precedence over glob patterns.

lld issues an error because
`assignWildcardVersion(ver, VER_NDX_LOCAL);` is processed before `assignExactVersion(ver, v.id, v.name);`.

Move all assignWildcardVersion() calls after assignExactVersion() calls
to fix this.

Also, move handleDynamicList() to the bottom. computeBinding() called by
includeInDynsym() has this cryptic rule:

    if (versionId == VER_NDX_LOCAL && isDefined() && !isPreemptible)
      return STB_LOCAL;

Before the change:

* foo's version is set to VER_NDX_LOCAL due to `local: *`
* handleDynamicList() is called
  - foo.computeBinding() is STB_LOCAL
  - foo.includeInDynsym() is false
  - foo.isPreemptible is not set (wrong)
* foo's version is set to V1

After the change:

* foo's version is set to VER_NDX_LOCAL due to `local: *`
* foo's version is set to V1
* handleDynamicList() is called
  - foo.computeBinding() is STB_GLOBAL
  - foo.includeInDynsym() is true
  - foo.isPreemptible is set (correct)

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D64550

llvm-svn: 365760
2019-07-11 11:16:51 +00:00
Fangrui Song be8275753f [ELF] Warn rather than error when duplicate version assignments occur
In lvm2, libdevmapper.so is linked with a version script with duplicate
version assignments:

    DM_1_02_138 { global: ... dm_bitset_parse_list; ... };
    DM_1_02_129 { global: ... dm_bitset_parse_list; ... };

ld.bfd silently accepts this while gold issues a warning. We currently
error, thus inhibit producing the executable. Change the error to
warning to allow this case, and improve the message.

There are some cases where ld.bfd error
`anonymous version tag cannot be combined with other version tags`
but we just warn. It is probably OK for now.

Reviewed By: grimar, ruiu

Differential Revision: https://reviews.llvm.org/D64549

llvm-svn: 365759
2019-07-11 11:16:44 +00:00
Rui Ueyama 77565f7690 Fix build breakage on Win32.
llvm-svn: 365737
2019-07-11 06:56:44 +00:00
Rui Ueyama f4954b52e4 Fix build breakage on Darwin.
llvm-svn: 365734
2019-07-11 06:12:18 +00:00
Rui Ueyama bfaf64ae57 Update comments for r365730. NFC.
llvm-svn: 365733
2019-07-11 06:08:54 +00:00
Rui Ueyama 76c3f6cdff Fix build breakage on Win32.
llvm-svn: 365732
2019-07-11 06:00:40 +00:00
Rui Ueyama 136d27ab4d [Coding style change][lld] Rename variables for non-ELF ports
This patch does the same thing as r365595 to other subdirectories,
which completes the naming style change for the entire lld directory.

With this, the naming style conversion is complete for lld.

Differential Revision: https://reviews.llvm.org/D64473

llvm-svn: 365730
2019-07-11 05:40:30 +00:00
Nikola Prica 6522bedefe Revert "[ELF] Update test case due to llvm r365618"
Reverting du to reverting r365618

This reverts commit b1e76d1d41c2303f70b53e352bdefbff2a2a9d37.

llvm-svn: 365686
2019-07-10 18:58:29 +00:00
Peter Collingbourne d37edd0c79 ELF: Add support for R_AARCH64_ADR_PREL_PG_HI21_NC relocation.
Differential Revision: https://reviews.llvm.org/D64456

llvm-svn: 365662
2019-07-10 16:42:20 +00:00
George Rimar c44a23f8f4 [LLD][ELF] - Linkerscript: fix FILL() expressions handling.
D64130 introduced a bug described in the following message:
https://reviews.llvm.org/D64130#1571560

The problem can happen with the following script:

SECTIONS {
  .out : {
...
   FILL(0x10101010)
   *(.aaa)
...
}

The current code tries to read (0x10101010) as an expression and
does not break when meets *, what results in a script parsing error.

In this patch, I verify that FILL command's expression always wrapped in ().
And at the same time =<fillexp> expression can be both wrapped or unwrapped.
I checked it matches to bfd/gold.

Differential revision: https://reviews.llvm.org/D64476

llvm-svn: 365635
2019-07-10 14:36:48 +00:00
Nikola Prica fcd978b0a6 [ELF] Update test case due to llvm r365618
llvm-svn: 365619
2019-07-10 11:19:44 +00:00
Rui Ueyama 7e296adec7 Make functions and member variables distinguishable even after the name style change. NFC.
llvm-svn: 365605
2019-07-10 09:10:01 +00:00
Rui Ueyama 3837f4273f [Coding style change] Rename variables so that they start with a lowercase letter
This patch is mechanically generated by clang-llvm-rename tool that I wrote
using Clang Refactoring Engine just for creating this patch. You can see the
source code of the tool at https://reviews.llvm.org/D64123. There's no manual
post-processing; you can generate the same patch by re-running the tool against
lld's code base.

Here is the main discussion thread to change the LLVM coding style:
https://lists.llvm.org/pipermail/llvm-dev/2019-February/130083.html
In the discussion thread, I proposed we use lld as a testbed for variable
naming scheme change, and this patch does that.

I chose to rename variables so that they are in camelCase, just because that
is a minimal change to make variables to start with a lowercase letter.

Note to downstream patch maintainers: if you are maintaining a downstream lld
repo, just rebasing ahead of this commit would cause massive merge conflicts
because this patch essentially changes every line in the lld subdirectory. But
there's a remedy.

clang-llvm-rename tool is a batch tool, so you can rename variables in your
downstream repo with the tool. Given that, here is how to rebase your repo to
a commit after the mass renaming:

1. rebase to the commit just before the mass variable renaming,
2. apply the tool to your downstream repo to mass-rename variables locally, and
3. rebase again to the head.

Most changes made by the tool should be identical for a downstream repo and
for the head, so at the step 3, almost all changes should be merged and
disappear. I'd expect that there would be some lines that you need to merge by
hand, but that shouldn't be too many.

Differential Revision: https://reviews.llvm.org/D64121

llvm-svn: 365595
2019-07-10 05:00:37 +00:00
Sam Clegg 9abe8c4805 [lld][WebAssembly] Report undefined symbols during scanRelocations
This puts handling of undefined symbols in a single location.  Its
also more in line with the ELF backend which only reports undefined
symbols based on relocations.

One side effect is that we no longer report undefined symbols that are
only referenced in GC'd sections.

This also fixes a crash reported in the emscripten toolchain:
https://github.com/emscripten-core/emscripten/issues/8930.

Differential Revision: https://reviews.llvm.org/D64280

llvm-svn: 365553
2019-07-09 20:45:20 +00:00
Sam Clegg 51c2b99eff [lld][WebAssembly] Fix name of data section in PIC mode
This should always have been ".data".  Without this we treat the
section as a user-defined section in other places (such as the
generation of __start/__stop symbols).

Differential Revision: https://reviews.llvm.org/D64439

llvm-svn: 365547
2019-07-09 19:47:32 +00:00
Nico Weber e7a67bf8ce lld-link: Stop accepting /natvis and /fastfail in .drectve sections
link.exe doesn't accept them either.

Differential Revision: https://reviews.llvm.org/D64352

llvm-svn: 365478
2019-07-09 13:30:03 +00:00
Fangrui Song 50e7f45b28 [ELF] Assert sizeof(SymbolUnion) <= 80
Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D64077

llvm-svn: 365443
2019-07-09 07:12:58 +00:00
Fangrui Song c117be6fc6 [ELF][test] Rename tail-merge-string-align2.s to merge-string-align2.s
This test was added by D64200/r365139 to check we don't merge
SHF_MERGE|SHF_STRINGS sections with different alignments (that wastes
space and can make MergeTailAlignment::Builder out of sync).

It has nothing to do with tail merge (-O2), so rename it.

llvm-svn: 365442
2019-07-09 06:10:21 +00:00
Denis Bakhvalov 92fb5f2e47 [LLD] NFC: Fixed GCC warning in ELF/Arch/RISCV.cpp
GCC emits warning on this line:
error: enumeral and non-enumeral type in conditional
expression [-Werror=extra]

Change-Id: I04969cc32e27e310968b88ebaa4e1c4894528d74
llvm-svn: 365434
2019-07-09 03:56:44 +00:00
Nico Weber e3f06b478c Let unaliased Args track which Alias they were created from, and use that in Arg::getAsString() for diagnostics
With this, `clang-cl /source-charset:utf-16 test.cc` now prints `invalid
value 'utf-16' in '/source-charset:utf-16'` instead of `invalid value
'utf-16' in '-finput-charset=utf-16'` before, and several other clang-cl
flags produce much less confusing output as well.

Fixes PR29106.

Since an arg and its alias can have different arg types (joined vs not)
and different values (because of AliasArgs<>), I chose to give the Alias
its own Arg object. For convenience, I just store the alias directly in
the unaliased arg – there aren't many arg objects at runtime, so that
seems ok.

Finally, I changed Arg::getAsString() to use the alias's representation
if it's present – that function was already documented as being the
suitable function for diagnostics, and most callers already used it for
diagnostics.

Implementation-wise, Arg::accept() previously used to parse things as
the unaliased option. The core of that switch is now extracted into a
new function acceptInternal() which parses as the _aliased_ option, and
the previously-intermingled unaliasing is now done as an explicit step
afterwards.

(This also changes one place in lld that didn't use getAsString() for
diagnostics, so that that one place now also prints the flag as the user
wrote it, not as it looks after it went through unaliasing.)

Differential Revision: https://reviews.llvm.org/D64253

llvm-svn: 365413
2019-07-09 00:34:08 +00:00
Bill Wendling 858e35160e Add parentheses to silence warnings.
llvm-svn: 365397
2019-07-08 22:05:02 +00:00
Sam Clegg 556ec990e9 [lld] Use -o /dev/null in test when output is not needed.
Fix for feedback nit from rL364998

llvm-svn: 365310
2019-07-08 11:14:10 +00:00
Sam Clegg 15006469bf [lld][WebAssembly] Fix __start/__stop symbols when combining input segments
We should be generating one __start/__stop pair per output segment
not per input segment.  The test wasn't catching this because it was
only linking a single object file.

Fixes PR41565

Differential Revision: https://reviews.llvm.org/D64148

llvm-svn: 365308
2019-07-08 10:35:08 +00:00
Sam Clegg d0e1d00397 [lld][WebAssembly] Fix typo in error message
Differential Revision: https://reviews.llvm.org/D64315

llvm-svn: 365304
2019-07-08 09:34:30 +00:00
Fangrui Song 34958d12c9 [WebAssembly] Add static_assert(sizeof(SymbolUnion) <= 96)
On Windows, the bitfield layout rule places `ussigned Referenced : 1` at
byte offset 40, instead of byte offset 37 on *NIX. The consequence is that
sizeof(SymbolUnion) == 104 on Windows while 96 on *NIX.

To eliminate this difference, change these unsigned bitfields to bool.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D64238

llvm-svn: 365296
2019-07-08 07:30:07 +00:00
Nico Weber a780276301 lld, llvm-dlltool, llvm-lib: Use getAsString() instead of getSpelling() for printing unknown args
Since OPT_UNKNOWN args never have any values and consist only of
spelling (and are never aliased), this doesn't make any difference in
practice, but it's more consistent with Arg's guidance to use
getAsString() for diagnostics, and it matches what clang does.

Also tweak two tests to use an unknown option that contains '=' for
additional coverage while here. (The new tests pass fine with the old
code too though.)

llvm-svn: 365200
2019-07-05 12:31:32 +00:00
Nico Weber cf1a11ded2 Make joined instances of JoinedOrSeparate flags point to the unaliased args, like all other arg types do
This fixes an 8-year-old regression. r105763 made it so that aliases
always refer to the unaliased option – but it missed the "joined" branch
of JoinedOrSeparate flags. (r162231 then made the Args classes
non-virtual, and r169344 moved them from clang to llvm.)

Back then, there was no JoinedOrSeparate flag that was an alias, so it
wasn't observable. Now /U in CLCompatOptions is a JoinedOrSeparate alias
in clang, and warn_slash_u_filename incorrectly used the aliased arg id
(using the unaliased one isn't really a regression since that warning
checks if the undefined macro contains slash or backslash and only then
emits the warning – and no valid use will pass "-Ufoo/bar" or similar).

Also, lld has many JoinedOrSeparate aliases, and due to this bug it had
to explicitly call `getUnaliasedOption()` in a bunch of places, even
though that shouldn't be necessary by design. After this fix in Option,
these calls really don't have an effect any more, so remove them.

No intended behavior change.

(I accidentally fixed this bug while working on PR29106 but then
wondered why the warn_slash_u_filename broke. When I figured it out, I
thought it would make sense to land this in a separate commit.)

Differential Revision: https://reviews.llvm.org/D64156

llvm-svn: 365186
2019-07-05 11:45:24 +00:00
George Rimar c9a5c631fe [LLD][ELF] - Update a test after LLVM change.
Error reporting changed in r365183

llvm-svn: 365184
2019-07-05 11:29:04 +00:00
Nico Weber fdef18b42d lld-link: Make /debugtype: option work better
- The code tried to pass false to split()'s KeepEmpty parameter, but
  instead passed it to MaxSplit. As a result, it would never split on
  commas. This has been broken since the flag was added in r278056.

- The code used getSpelling() for getting the argument's values, but
  getSpelling() always returns the `/debugtype:` prefix without any
  values. So if any /debugtype: flag was passed, it always resulted in
  an "unknown option:" warning. (The warning code then used the correct
  getValue() for printing the invalid option, so the warning looked
  kind of like it made sense.) This regressed in r342894.

Slightly improve the test coverage of this feature (but since I don't
know what this flag actually does, there's still no test for the correct
semantics), and add a comment to getSpelling() explaining what it does.

llvm-svn: 365182
2019-07-05 11:28:31 +00:00
Fangrui Song c4339f1051 [WebAssembly] Delete static_assert(sizeof(SymbolUnion) <= 96) to fix Windows builds
http://lab.llvm.org:8011/builders/sanitizer-windows/builds/47944/steps/stage%201%20build/logs/stdio

Needs to figure out later the size on Windows.

llvm-svn: 365171
2019-07-05 01:45:12 +00:00
Fangrui Song 3d0193909b [WebAssembly] Reorder Symbol fields to make it smaller
On 64-bit systems, this decreases sizeof(SymbolUnion) from 112 to 96.

Add a static_assert to avoid accidental increases in future.

Reviewed By: sbc100

Differential Revision: https://reviews.llvm.org/D64208

llvm-svn: 365169
2019-07-05 01:27:39 +00:00
George Rimar 0810f16fb9 [LLD][ELF] - Linkerscript: add a support for expressions for section's filling
Imagine the script:

.section: {
...
} = FILL_EXPR
LLD assumes that FILL_EXPR is a number, and does not allow
it to be an expression. Though that is allowed by specification:
https://sourceware.org/binutils/docs-2.32/ld/Output-Section-Fill.html

This patch adds a support for cases when FILL_EXPR is simple math expression.

Fixes https://bugs.llvm.org/show_bug.cgi?id=42482.

Differential revision: https://reviews.llvm.org/D64130

llvm-svn: 365143
2019-07-04 14:17:31 +00:00
Fangrui Song 5c4bbc2746 [ELF] Allow placing non-string SHF_MERGE sections with different alignments into the same MergeSyntheticSection
The difference from D63432/r365015 is that this patch does not place
SHF_STRINGS sections with different alignments into the same
MergeSyntheticSection. Doing that would:

(1) create unnecessary padding and thus waste space.
  Add a test tail-merge-string-align2.s to check no extra padding is created.
(2) make some input sections unaligned when tail merge (-O2) is enabled.
  The alignment of MergeTailAlignment::Builder was out of sync in D63432.
  MOVAPS on such unaligned strings can raise SIGSEGV.

This should fix PR42289: the Linux kernel has a use case that input
files have .rodata.cst32 sections with different alignments. The
expectation (and what ld.bfd and gold do) is that in the -r link, there
is only one .rodata.cst32 (SHF_MERGE sections with different alignments
can be combined), but lld currently creates one for each different
alignment.

The current merging strategy:

1) Group SHF_MERGE sections by (name, sh_flags, sh_entsize and
   sh_addralign). Merging is performed among a group, even if -O0 is specified.
2) Create one output section for each group. This is a special case in
   addInputSec().

This patch changes 1) to:

1) Group SHF_MERGE sections by (name, sh_flags, sh_entsize).
   Merging is performed among a group, even if -O0 is specified.

We will thus create just one .rodata.cst32 . This also improves merging
efficiency when sections with the same name but different alignments are
combined.

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D64200

llvm-svn: 365139
2019-07-04 13:33:27 +00:00
Fangrui Song f13735fcae [ELF] Fix weak-undef-shared.s after r365129
llvm-svn: 365131
2019-07-04 11:10:45 +00:00
Fangrui Song f347541fbc [ELF] resolveUndefined: ignore undefined symbols in SharedFile for Undefined and SharedSymbol
If %t1.o has a weak reference on foo, and %t2.so has a non-weak
reference on foo: `ld.lld %t1.o %t2.so -o %t`

We incorrectly set the binding of the undefined foo to STB_GLOBAL.
Fix this by ignoring undefined symbols in a SharedFile for Undefined and
SharedSymbol.

This fixes the binding of pthread_once when the program links against
both librt.so and libpthread.so

```
a.o: STB_WEAK reference to pthread_once
librt.so: STB_GLOBAL reference to pthread_once    # should be ignored
libstdc++.so: STB_WEAK reference to pthread_once  # should be ignored
libgcc_s.so.1: STB_WEAK reference to pthread_once # should be ignored
```

The STB_GLOBAL pthread_once issue (not fixed by D63974) can cause a link error when the result
DSO is used to link another DSO with -z defs if -lpthread is not specified. (libstdc++.so.6 not having a dependency on libpthread.so is a really nasty hack...)

We happened to create a weak undef before D63974 because libgcc_s.so.1
was linked the last and it changed the binding again to weak.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D64136

llvm-svn: 365129
2019-07-04 10:38:04 +00:00
Thomas Lively 6004d9a13d [WebAssembly] Add option to emit passive segments
Summary:
Adds `--passive-segments` and `--active-segments` flags to control
what kind of segments are emitted. For now the default is always
to emit active segments so this is not a breaking change, but in
the future the default will be changed to passive segments when
shared memory is requested and active segments otherwise. When
passive segments are emitted, corresponding memory.init and
data.drop instructions are emitted in a `__wasm_init_memory`
function that is automatically called at the beginning of
`__wasm_call_ctors`.

Reviewers: sbc100, aheejin, dschuff

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59343

llvm-svn: 365088
2019-07-03 22:04:54 +00:00
Fangrui Song 4e225deab4 [ELF][RISCV] Error on R_RISCV_PCREL_LO12_[IS] that point to absolute symbols
The referenced symbol is expected to point to an R_RISCV_*_HI20
relocation. An absolute symbol has no associated section, therefore
there cannot be a matching R_RISCV_*_HI20.

This fixes the crash reported by PR42038. For reference, ld.bfd errors:

    (.init+0x4): dangerous relocation: %pcrel_lo missing matching %pcrel_hi

Differential Revision: https://reviews.llvm.org/D63273

llvm-svn: 365049
2019-07-03 15:38:59 +00:00
Fangrui Song b9bc9f67f5 Revert D63432 "[ELF] Allow placing SHF_MERGE sections with different alignments into the same MergeSyntheticSection"
This reverts r365015.

David Zarzycki reported this change broke stage2 and stage3 tests.  The
root cause is still not very clear, but I guess some SHF_MERGE sections
with the same name have different alignments. They were not merged
before but were merged after r365015.

Something that assumes address uniqueness of such mergeable data caused
the bug.

llvm-svn: 365048
2019-07-03 15:26:54 +00:00
Fangrui Song 5cf3cc6246 [ELF][RISCV] Allow R_RISCV_ADD in relocateNonAlloc()
gcc may generate .debug_info/.debug_aranges/.debug_line/etc that are
relocated by R_RISCV_ADD*/R_RISCV_SUB* pairs.
Allow R_RISCV_ADD in non-SHF_ALLOC section to fix link errors like:

    ld.lld: error: print.c:(.debug_frame+0x60): has non-ABS relocation R_RISCV_ADD64 against symbol '.L0 '

Differential Revision: https://reviews.llvm.org/D63259

llvm-svn: 365035
2019-07-03 12:48:04 +00:00
Fangrui Song 347692e2de [ELF] Allow placing SHF_MERGE sections with different alignments into the same MergeSyntheticSection
This should fix PR42289: the Linux kernel has a use case that input
files have .rodata.cst32 sections with different alignments. The
expectation (and what ld.bfd and gold do) is that in the -r link, there
is only one .rodata.cst32 (SHF_MERGE sections with different alignments
can be combined), but lld currently creates one for each different
alignment.

The current merging strategy:

1) Group SHF_MERGE sections by (name, sh_flags, sh_entsize and
   sh_addralign). String merging is performed among a group, even if -O0 is specified.
2) Create one output section for each group. This is a special case in
   addInputSec().

This patch changes 1) to:

1) Group SHF_MERGE sections by (name, sh_flags, sh_entsize).
   String merging is performed among a group, even if -O0 is specified.

We will thus create just one .rodata.cst32 . This also improves merging
efficiency when sections with the same name but different alignments are
combined.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D63432

llvm-svn: 365015
2019-07-03 10:03:49 +00:00
Rui Ueyama 09a0d3d1a2 Avoid identifiers that are different only in case. NFC.
llvm-svn: 365004
2019-07-03 07:08:27 +00:00
Rui Ueyama 11ae59f0ce Avoid identifiers that are different only in case. NFC.
Some variables in lld have the same name as functions ignoring case.
This patch gives them different names, so that my next patch is easier
to read.

llvm-svn: 365003
2019-07-03 06:11:50 +00:00
Rui Ueyama 556305fc44 Revert r364999: [lld] Use -o /dev/null in test when output is not needed.
This reverts commit r364999 as it broke a build. Looks like `%t.archive.o`
is used two lines below where it was created.

llvm-svn: 365001
2019-07-03 05:52:35 +00:00
Sam Clegg d5bea6e0c1 [lld] Use -o /dev/null in test when output is not needed.
Feedback nit from rL364998

llvm-svn: 364999
2019-07-03 02:41:00 +00:00
Sam Clegg 99745896ce [ELF] Error on archive with missing index
This matches the wasm lld and GNU ld behavior.

The ELF linker has special handling for bitcode archives but if that
doesn't kick in we probably want to error out rather than silently
ignore the library.

Differential Revision: https://reviews.llvm.org/D63781

llvm-svn: 364998
2019-07-03 02:29:02 +00:00
Kito Cheng eb9bc38276 [ELF][RISCV] Support RISC-V in getBitcodeMachineKind
Add Triple::riscv64 and Triple::riscv32 to getBitcodeMachineKind for get right
e_machine during LTO.

Reviewed By: ruiu, MaskRay

Differential Revision: https://reviews.llvm.org/D52165

llvm-svn: 364996
2019-07-03 02:13:11 +00:00
Fangrui Song 1c70d136fb [ELF] Only allow the binding of SharedSymbol to change for the first undef ref
Fixes PR42442

t.o has a STB_GLOBAL undef ref to f
t2.so has a STB_WEAK undef ref to f
t1.so defines f

ld.lld t.o t1.so t2.so currently sets the binding of `f` to STB_WEAK.
This is not correct because there exists a STB_GLOBAL undef ref from a
regular object. The problem is that resolveUndefined() doesn't check
if the undef ref is seen for the first time:

    if (isShared() || isLazy() || (isUndefined() && Other.Binding != STB_WEAK))
      Binding = Other.Binding;

The isShared() condition should be `isShared() && !Referenced`
where Referenced is set to true after an undef ref is seen.

In practice, when linking a pthread program with glibc:

    // a.o
    #include <pthread.h>
    pthread_mutex_t mu = PTHREAD_MUTEX_INITIALIZER;
    int main() { pthread_mutex_unlock(&mu); }

{clang,gcc} -fuse-ld=lld a.o -lpthread # libpthread.so is linked before libgcc_s.so.1

The weak undef pthread_mutex_unlock in libgcc_s.so.1 makes the result
weak, which diverges from GNU linkers where STB_DEFAULT is used:

    23: 0000000000000000     0 FUNC    WEAK   DEFAULT  UND pthread_mutex_lock

(Note, if -pthread is used instead, libpthread.so will be linked **after**
libgcc_s.so.1 . lld sets the binding to the expected STB_GLOBAL)

Similar linking sequences (ld.lld t.o t1.so t2.so) appear to be used by
Go, which cause a build error https://github.com/golang/go/issues/31912.

Reviewed By: grimar, ruiu

Differential Revision: https://reviews.llvm.org/D63974

llvm-svn: 364913
2019-07-02 11:37:21 +00:00
Fangrui Song ddc57afab9 [ELF][RISCV] Support GD/LD/IE/LE TLS models
RISC-V psABI doesn't specify TLS relaxation. It can be handled the same
way as we handle ARM TLS. RISC-V TLS is even simpler because GD/LD use
the same relocation type.

Reviewed By: jrtc27, ruiu

Differential Revision: https://reviews.llvm.org/D63220

llvm-svn: 364813
2019-07-01 17:12:26 +00:00
Fangrui Song f01fa40a00 [ELF][RISCV] Support PLT, GOT, copy and relative relocations
* Handle initial relocation types: R_RISCV_CALL_PLT and R_RISCV_GOT_HI20.
* Produce dynamic relocation types: R_RISCV_COPY, R_RISCV_RELATIVE, R_RISCV_JUMP_SLOT.
* Define SymbolRel as R_RISCV_{32,64}
* Generate PLT header: it is used by lazy binding PLT in glibc.
* R_RISCV_CALL is changed from R_PC to R_PC_PLT. If the target symbol is preemptable, this will suppress an unnecessary "canonical PLT".
  This behavior is different from ld.bfd but it is agreed the current lld behavior is favored.
  I have received positive responses from the binutils maintainer that the ABI/binutils implementation can be improved, see:
  https://github.com/riscv/riscv-elf-psabi-doc/issues/98
  https://sourceware.org/bugzilla/show_bug.cgi?id=24685

Many -no-pie/-pie/-shared programs linked against musl or glibc should work with this patch.

Reviewed By: jrtc27

Differential Revision: https://reviews.llvm.org/D63076

llvm-svn: 364812
2019-07-01 17:12:18 +00:00
Fangrui Song 78ee2fbf98 Cleanup: llvm::bsearch -> llvm::partition_point after r364719
llvm-svn: 364720
2019-06-30 11:19:56 +00:00
Martin Storsjo 5cbff43178 [COFF] Fix .rsrc sections with differing permissions
GNU windres, and MS cvtres (unless the /readonly option is passed)
produce read-write .rsrc sections, when creating resource object files.
This caused the sections to not be added to the precreated RsrcSec,
and therefore not be added to the data directory.

Differential Revision: https://reviews.llvm.org/D63837

llvm-svn: 364660
2019-06-28 17:13:52 +00:00
Igor Kudrin fd0ad4b24d [ELF] Do not produce DT_JMPREL and DT_PLTGOT if .rela.plt is empty.
If .rela.plt is mentioned in a linker script, it might be preserved
even if it is empty. In that case, LLD created DT_JMPREL and DT_PLTGOT
dynamic tags. When the tags exist, a dynamic loader writes values into
reserved slots in .got.plt to support lazy symbol resolution.
The problem is that, in fact, the linker has not reserved that space,
and the writing may occur into the memory allocated for something else.

Differential Revision: https://reviews.llvm.org/D63869

llvm-svn: 364639
2019-06-28 10:14:14 +00:00
Michael Liao a166b903d0 Fix lld build on Windows with MSVC due to C2461
- It seems the same name of class and one of its fields confuses MSVC,
  https://docs.microsoft.com/en-us/cpp/error-messages/compiler-errors-1/compiler-error-c2461?view=vs-2019
- Patch from Andryeyev, German <german.andryeyev@amd.com>

llvm-svn: 364567
2019-06-27 17:19:28 +00:00
George Rimar f4f608d1f4 [LLD][ELF] - Replace invalid-e_shnum.s with YAML based version.
The previous version used a precompiled binary.

After this patch, we have no more precompiled binaries
in LLD ELF test suite :)

llvm-svn: 364529
2019-06-27 12:23:38 +00:00
Guanzhong Chen e15dc95466 [wasm-ld] Add __global_base symbol to mark the value of --global-base
Summary:
This is needed for address sanitizer on Emscripten. As everything in
memory starts at the value passed to --global-base, everything before
that can be used as shadow memory.

This symbol is added so that the library for the ASan runtime can know
where the shadow memory ends and real memory begins.

This is split from D63742.

Reviewers: tlively, aheejin, sbc100

Subscribers: sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63833

llvm-svn: 364467
2019-06-26 20:12:33 +00:00
Alexandre Ganea 90079977ac [LLD][COFF] Case insensitive compares for /nodefaultlib
Differential Revision: https://reviews.llvm.org/D63775

llvm-svn: 364438
2019-06-26 15:40:17 +00:00
Fangrui Song ba51fd5664 Reland D61583 [ELF] Error on relocations to STT_SECTION symbols if the sections were discarded
This restores r361830 "[ELF] Error on relocations to STT_SECTION symbols if the sections were discarded"
and dependent commits (r362218, r362497) which were reverted by r364321, with a fix of a --gdb-index issue.

.rela.debug_ranges contains relocations of range list entries:

    // start address of a range list entry
    // old: 0; after r361830: 0
    00000000000033a0 R_X86_64_64 .text._ZN2v88internal7Isolate7factoryEv + 0
    // end address of a range list entry
    // old: 0xe; after r361830: 0
    00000000000033a8 R_X86_64_64 .text._ZN2v88internal7Isolate7factoryEv + e

If both start and end addresses of a range list entry resolve to 0,
DWARFDebugRangeList::isEndOfListEntry() will return true, then the
.debug_range decoding loop will terminate prematurely:

    while (true) {
      decode StartAddress
      decode EndAddress
      if (Entry.isEndOfListEntry()) // prematurely
        break;
      Entries.push_back(Entry);
    }

In lld/ELF/SyntheticSections.cpp, readAddressAreas() will read
incomplete address ranges and the resulting .gdb_index will be
incomplete. For files that gdb hasn't loaded their debug info, gdb uses
.gdb_index to map addresses to CUs. The absent entries make gdb fail to
symbolize some addresses.

To address this issue, we simply allow relocations to undefined symbols
in DWARF.cpp:findAux() and let RelocationResolver resolve them.

This patch should fix:

[1] http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20190603/659848.html
[2] https://bugs.chromium.org/p/chromium/issues/detail?id=978067

llvm-svn: 364391
2019-06-26 08:09:08 +00:00
Keno Fischer 5bb0dcd96e [WebAssembly] Fix accidental omission from rLLD364367
There was another place where handling for this relocation was missing
that was accidentally omitted from rLLD364367, causing the newly added
test to fail on the buildbots.

llvm-svn: 364371
2019-06-26 01:26:53 +00:00
Keno Fischer c5b8e1c538 [lld/WebAssembly] Slightly nicer error message for malformed input files
Summary:
Before:
```
wasm-ld: error: Relocations not in offset order
```
After
```
wasm-ld: error: While processing `libjulia.so`: Relocations not in offset order
```

At least this way you get to find out which input file is malformed.

Reviewers: sbc100
Differential Revision: https://reviews.llvm.org/D63694

llvm-svn: 364368
2019-06-26 00:52:46 +00:00
Keno Fischer cadcb9eb61 [WebAssembly] Fix list of relocations with addends in lld
Summary:
The list of relocations with addend in lld was missing `R_WASM_MEMORY_ADDR_REL_SLEB`,
causing `wasm-ld` to generate corrupted output. This fixes that problem and while
we're at it pulls the list of such relocations into the Wasm.h header, to avoid
duplicating it in multiple places.

Reviewers: sbc100
Differential Revision: https://reviews.llvm.org/D63696

llvm-svn: 364367
2019-06-26 00:52:42 +00:00
Sam Clegg 61d70e4a93 [WebAssembly] Error on archives without a symbol index
This is fairly common with wasm since GNU ar (most likely the system ar)
doesn't support the wasm object format so user who don't override AR
will end up with archives without an index.  We don't want to silently
ignore this issue.

In the future we could choose to instead behave like the ELF backend and
read the symbols from each object file in the archive if they are all of
the same type.  However, error'ing out seem like a conservative approach
for now.

Fixes: PR42376

Differential Revision: https://reviews.llvm.org/D63739

llvm-svn: 364338
2019-06-25 17:49:35 +00:00
Hans Wennborg 36c23cad15 Revert r362743 "Revert "Revert "Reland D61583 [ELF] Error on relocations to STT_SECTION symbols if the sections were discarded"""
(In effect, reverting "[ELF] Error on relocations to STT_SECTION symbols if the sections were discarded".)

It caused debug info problems in LibreOffice [1] and Chromium/V8 [2].
Reverting until those can be fixed.

It also reverts r362497 "STT_SECTION symbol should be defined" on .eh_frame, .debug*, .zdebug* and .gcc_except_table"
which was landed as a follow-up to the above.

> With -r or --emit-relocs, we warn `STT_SECTION symbol should be defined`
> on relocations to discarded section symbol. This was added as an error
> in rLLD319404, but was not so effective before D61583 (it turned the
> error to a warning).
>
> Relocations from .eh_frame .debug* .zdebug* .gcc_except_table to
> discarded .text are very common and somewhat expected. Don't warn/error
> on them. As a reference, ld.bfd has a similar logic in
> _bfd_elf_default_action_discarded() to allow these cases.
>
> Delete invalid-undef-section-symbol.test because what it intended to
> check is now covered by the updated comdat-discarded-reloc.s
>
> Delete relocatable-eh-frame.s because we allow relocations from
> .eh_frame as a special case now.

And finally it reverts r362218 "[ELF] Replace a dead test in getSymVA() with assert()"
as that also depended on the main change reverted here.

> Symbols relative to discarded comdat sections are Undefined instead of
> Defined now (after D59649 and D61583). The `== &InputSection::Discarded`
> test becomes dead. I cannot find a test related to this behavior.

 [1] http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20190603/659848.html
 [2] https://bugs.chromium.org/p/chromium/issues/detail?id=978067

llvm-svn: 364321
2019-06-25 14:58:46 +00:00
Nico Weber 0142b9ce31 Port r363962 to COFF: Deduplicate undefined symbol diagnostics
lld/coff already deduplicated undefined symbols on a TU level: It would
group all references to a symbol from a single TU. This makes it so that
references from all TUs to a single symbol are grouped together.

Since lld/coff almost did what I thought it did already, the patch is
much smaller than the elf version. The only not local change is that
getSymbolLocations() now returns a vector<string> instead of a string,
so that the undefined symbol reporting code can know how many references
to a symbol exist in a given TU.

Fixes PR42260 for lld/coff.

Differential Revision: https://reviews.llvm.org/D63646

llvm-svn: 364285
2019-06-25 09:55:55 +00:00
Rui Ueyama e63ae7fee4 Fix an issue that common symbols are not internalized under some condition.
r360841 introduced CommonSymbol class. An unintended behavioral change
introduced by that change was that common symbols are not internalized
by LTO under some condition. This patch fixes that issue.

The issue occurred under the following condition:

  1. There exists a common symbol
  2. At least one DSO is given to lld or -pie is used

If the above conditions are met, Symbol::includeInDynsym() returned a
wrong value for a common symbol.

Fixes https://bugs.llvm.org/show_bug.cgi?id=41978

Differential Revision: https://reviews.llvm.org/D63752

llvm-svn: 364273
2019-06-25 06:58:07 +00:00
Fangrui Song 2fb6b0f2ba [ELF][PPC][X86] Use [-2**(n-1), 2**n) to check overflows for R_PPC_ADDR16, R_PPC64_ADDR{16,32}, R_X86_64_{8,16}
Similar to R_AARCH64_ABS32, R_PPC64_ADDR32 can represent either a signed
value or unsigned value, thus we should use `[-2**(n-1), 2**n)` instead of
`[-2**(n-1), 2**(n-1))` to check overflows.

The issue manifests as a bogus linker error when linking the powerpc64le Linux kernel.
The new behavior is compatible with ld.bfd's complain_overflow_bitfield.

The upper bound of the error message is not correct. Fix it as well.

The changes to R_PPC_ADDR16, R_PPC64_ADDR16, R_X86_64_8 and R_X86_64_16 are similar.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D63690

llvm-svn: 364164
2019-06-24 05:37:20 +00:00
Nico Weber 2c45043415 lld/elf: Deduplicate undefined symbol diagnostics
Before:

```
ld.lld: error: undefined symbol: f()
>>> referenced by test.cc:3
>>>               /var/folders/c5/8d7sdn1x2mg92mj0rndghhdr0000gn/T/test-9c0808.o:(g())

ld.lld: error: undefined symbol: f()
>>> referenced by test.cc:4
>>>               /var/folders/c5/8d7sdn1x2mg92mj0rndghhdr0000gn/T/test-9c0808.o:(h())

ld.lld: error: undefined symbol: f()
>>> referenced by test.cc:5
>>>               /var/folders/c5/8d7sdn1x2mg92mj0rndghhdr0000gn/T/test-9c0808.o:(j())

ld.lld: error: undefined symbol: k()
>>> referenced by test.cc:5
>>>               /var/folders/c5/8d7sdn1x2mg92mj0rndghhdr0000gn/T/test-9c0808.o:(j())

ld.lld: error: undefined symbol: f()
>>> referenced by test2.cc:2
>>>               /var/folders/c5/8d7sdn1x2mg92mj0rndghhdr0000gn/T/test2-07b391.o:(asdf())
clang: error: linker command failed with exit code 1 (use -v to see invocation)
```

Now:

```
ld.lld: error: undefined symbol: f()
>>> referenced by test.cc:3
>>>               /var/folders/c5/8d7sdn1x2mg92mj0rndghhdr0000gn/T/test-0e07ba.o:(g())
>>> referenced by test.cc:4
>>>               /var/folders/c5/8d7sdn1x2mg92mj0rndghhdr0000gn/T/test-0e07ba.o:(h())
>>> referenced by test.cc:5
>>>               /var/folders/c5/8d7sdn1x2mg92mj0rndghhdr0000gn/T/test-0e07ba.o:(j())
>>> referenced by test2.cc:2
>>>               /var/folders/c5/8d7sdn1x2mg92mj0rndghhdr0000gn/T/test2-6bdb24.o:(asdf())

ld.lld: error: undefined symbol: k()
>>> referenced by test.cc:5
>>>               /var/folders/c5/8d7sdn1x2mg92mj0rndghhdr0000gn/T/test-0e07ba.o:(j())
clang: error: linker command failed with exit code 1 (use -v to see invocation)
```

If there are more than 10 references to an undefined symbol, only the
first 10 are printed.

Fixes PR42260.

Differential Revision: https://reviews.llvm.org/D63344

llvm-svn: 363962
2019-06-20 18:25:57 +00:00
Fangrui Song 249fde8583 [ELF][ARM][AARCH64][MIPS][PPC] Simplify the logic to create R_*_RELATIVE for absolute relocation types in writable sections
Summary:
Our rule to create R_*_RELATIVE for absolute relocation types were
loose. D63121 made it stricter but it failed to create R_*_RELATIVE for
R_ARM_TARGET1 and R_PPC64_TOC. rLLD363236 worked around that by
reinstating the original behavior for ARM and PPC64.

This patch is an attempt to simplify the logic.

Note, in ld.bfd, R_ARM_TARGET2 --target2=abs also creates
R_ARM_RELATIVE. This seems a very uncommon scenario (moreover,
--target2=got-rel is the default), so I do not implement any logic
related to it.

Also, delete R_AARCH64_ABS32 from AArch64::getDynRel. We don't have
working ILP32 support yet. Allowing it would create an incorrect
R_AARCH64_RELATIVE.

For MIPS, the (if SymbolRel, then RelativeRel) code is to keep its
behavior unchanged.

Note, in ppc64-abs64-dyn.s, R_PPC64_TOC gets an incorrect addend because
computeAddend() doesn't compute the correct address. We seem to have the
wrong behavior for a long time. The important thing seems that a dynamic
relocation R_PPC64_TOC should not be created as the dynamic loader will
error R_PPC64_TOC is not supported.

Reviewers: atanasyan, grimar, peter.smith, ruiu, sfertile, espindola

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D63383

llvm-svn: 363928
2019-06-20 14:00:08 +00:00
Fangrui Song ffed2c96d9 [ELF][ARM] Merge handleARMTlsRelocation() into handleTlsRelocation()
ARM and RISC-V do not support TLS relaxations. However, for General
Dynamic and Local Dynamic models, if we are producing an executable and
the symbol is non-preemptable, we know it must be defined and the
R_ARM_TLS_DTPMOD32/R_RISCV_TLS_DTPMOD{32,64} dynamic relocation can be
omitted because it is always 1. This may be necessary for static linking
as DTPMOD may not be expected at load time.

Merge handleARMTlsRelocation() into handleTlsRelocation(). This requires
more logic to R_TLSGD_PC and R_TLSLD_PC. Because we use SymbolicRel to
resolve the relocation at link time, R_ARM_TLS_DTPMOD32 can be deleted
from relocateOne(). It cannot be used as a static relocation type.

As a bonus, the additional logic in R_TLSGD_PC code can be shared by the
TLS support for RISC-V (D63220).

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D63333

llvm-svn: 363927
2019-06-20 13:53:11 +00:00
Yuanfang Chen 40a156b791 [llvm-readobj] Match GNU output for DT_RPATH and DT_RUNPATH when dumping dynamic symbol table.
Reviewers: jhenderson, grimar, MaskRay, rupprecht, espindola

Subscribers: emaste, nemanjai, arichardson, kbarton, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63347

llvm-svn: 363868
2019-06-19 19:31:07 +00:00
Reid Kleckner a702f07301 [PDB] Ignore .debug$S subsections with high bit set
Some versions of the Visual C++ 2015 runtime have line tables with the
subsection kind of 0x800000F2. In cvinfo.h, 0x80000000 is documented to
be DEBUG_S_IGNORE. This appears to implement the intended behavior.

llvm-svn: 363724
2019-06-18 19:41:25 +00:00
Francis Visoiu Mistrih 34667519dc [Remarks] Extend -fsave-optimization-record to specify the format
Use -fsave-optimization-record=<format> to specify a different format
than the default, which is YAML.

For now, only YAML is supported.

llvm-svn: 363573
2019-06-17 16:06:00 +00:00
Fangrui Song 46f9cbe28d [llvm-objdump] Use %08 instead of %016 to print leading addresses for 32-bit binaries
Reviewed By: grimar

Differential Revision: https://reviews.llvm.org/D63398

llvm-svn: 363539
2019-06-17 09:59:55 +00:00
Reid Kleckner 05e48cb9fa Include the file in the new unknown codeview subsection warning
llvm-svn: 363466
2019-06-14 22:03:23 +00:00
Martin Storsjo 2de984cd30 [COFF] Strip section name suffix from mingw comdats
This is the second part of the fix for PR42217.

Differential Revision: https://reviews.llvm.org/D63352

llvm-svn: 363457
2019-06-14 21:02:09 +00:00
Martin Storsjo c3b1d730d6 [COFF] Handle .eh_frame$symbol as associative comdat for MinGW
This matches how it is done for .xdata and .pdata already.

On i386, the symbol name in the section name suffix does not contain
the extra underscore prefix.

This is one part of a fix for PR42217.

Differential Revision: https://reviews.llvm.org/D63350

llvm-svn: 363456
2019-06-14 21:02:04 +00:00
Martin Storsjo ff4e0a9f3e [MinGW] Support the --subsystem=val option in joined form
Differential Revision: https://reviews.llvm.org/D63250

llvm-svn: 363433
2019-06-14 17:50:39 +00:00
Martin Storsjo 6f047ae58b [MinGW] Support the --{major,minor}-{os,subsystem}-version options
This fixes PR42218.

Differential Revision: https://reviews.llvm.org/D63249

llvm-svn: 363432
2019-06-14 17:50:35 +00:00
Martin Storsjo b20fefc89b [COFF] Allow setting subsystem versions while inferring the subsystem type implicitly
Differential Revision: https://reviews.llvm.org/D63248

llvm-svn: 363431
2019-06-14 17:50:29 +00:00
Nico Weber bea1286155 Wrap a test to 80 columns
llvm-svn: 363421
2019-06-14 16:47:07 +00:00
Nico Weber 96a15796fb Remove two unused parameters
llvm-svn: 363419
2019-06-14 16:46:02 +00:00
George Rimar 76d575312d [LLD][ELF] - Fix test case after r363401
llvm-svn: 363402
2019-06-14 14:26:34 +00:00
Fangrui Song e05ca38101 [ELF] Don't emit dynamic relocations with weak undef in writable sections
In processRelocAux(), our handling of 1) link-time constant and 2) weak
undef is the same, so put them together to simplify the logic.

This moves the weak undef code around. The result is that: in a writable
section (or -z notext), we will no longer emit dynamic relocations for
weak undefined symbols.

The new behavior seems to match GNU linkers, and improves consistency
with the case of a readonly section.

The condition `!Config->Shared` was there probably because it is common
for a -shared link not to specify full dependencies. Keep it now but we
may revisit the decision in the future.

gABI says:

> The behavior of weak symbols in areas not specified by this document is
> implementation defined. Weak symbols are intended primarily for use in
> system software. Applications using weak symbols are unreliable since
> changes in the runtime environment might cause the execution to fail.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D63003

llvm-svn: 363399
2019-06-14 14:09:15 +00:00
George Rimar a59bc6e589 Revert r363395.
It will not work because of r363394.

llvm-svn: 363398
2019-06-14 14:06:03 +00:00
Nico Weber a35b935d39 lld/coff: slightly simplify ImportFile::parse()
llvm-svn: 363397
2019-06-14 14:03:08 +00:00
Rui Ueyama 43f4b037d5 Add --undefined-glob which is an --undefined with wildcard pattern match
This patch adds new command line option `--undefined-glob` to lld.
That option is a variant of `--undefined` but accepts wildcard
patterns so that all symbols that match with a given pattern are
handled as if they were given by `-u`.

`-u foo` is to force resolve symbol foo if foo is not a defined symbol
and there's a static archive that contains a definition of symbol foo.

Now, you can specify a wildcard pattern as an argument for `--undefined-glob`.
So, if you want to include all JNI symbols (which start with "Java_"), you
can do that by passing `--undefined-glob "Java_*"` to the linker, for example.

In this patch, I use the same glob pattern matcher as the version script
processor is using, so it does not only support `*` but also `?` and `[...]`.

Differential Revision: https://reviews.llvm.org/D63244

llvm-svn: 363396
2019-06-14 14:00:59 +00:00
George Rimar a0b0d626ab [ELF] - Attemp to fix BB.
Seems section has a wrong type.

http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-ubuntu-fast/builds/28

llvm-svn: 363395
2019-06-14 13:59:27 +00:00
Fangrui Song 5b4285d82d [ELF][RISCV] Create dummy .sdata for __global_pointer$ if .sdata does not exist
If .sdata is absent, linker synthesized __global_pointer$ gets a section index of SHN_ABS.
(ld.bfd has a similar issue: binutils PR24678)

Scrt1.o may use `lla gp, __global_pointer$` to reference the symbol PC
relatively. In -pie/-shared mode, lld complains if a PC relative
relocation references an absolute symbol (SHN_ABS) but ld.bfd doesn't:

    ld.lld: error: relocation R_RISCV_PCREL_HI20 cannot refer to lute symbol: __global_pointer$

Let the reference of __global_pointer$ to force creation of .sdata to
fix the problem. This is similar to _GLOBAL_OFFSET_TABLE_, which forces
creation of .got or .got.plt .

Also, change the visibility from STV_HIDDEN to STV_DEFAULT and don't
define the symbol for -shared. This matches ld.bfd, though I don't
understand why it uses STV_DEFAULT.

Reviewed By: ruiu, jrtc27

Differential Revision: https://reviews.llvm.org/D63132

llvm-svn: 363351
2019-06-14 02:14:53 +00:00
Eugene Leviant 0eb763c559 [lld][ELF] Add tests for bad subsection length in .ARM.attributes
Differential revision: https://reviews.llvm.org/D63191

llvm-svn: 363261
2019-06-13 13:41:28 +00:00
Fangrui Song a78e025558 [ELF] Loosen the condition that changes absolute relocation types to relative relocations for ARM and PPC64
Try fixing build bots after D63121

llvm-svn: 363236
2019-06-13 08:45:22 +00:00
Reid Kleckner 5584ab89a8 [lld] Fix type server merging with PDBs without IPI stream
PDBs may not necessarily contain an IPI stream. Handle this case
gracefully.

The test case was verified to work with MS link.exe.

Patch by Vladimir Panteleev, with a small simplification

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D63178

llvm-svn: 363213
2019-06-12 22:33:16 +00:00
Reid Kleckner efc01eac17 [lld] Allow unrecognized signatures in debug sections
An unrecognized signature (magic) at the beginning of a debug section
should not be a fatal error; it only means that the debug information
is in a format that is not supported by LLD. This can be due to it
being in CodeView versions 3 or earlier. These can occur in old import
libraries from legacy SDKs.

The test case was verified to work with MS link.exe.

Patch by Vladimir Panteleev!

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D63177

llvm-svn: 363212
2019-06-12 22:22:44 +00:00
Nico Weber 1dc2123d64 Share /machine: handling code with llvm-cvtres too
r363016 let lld-link and llvm-lib share the /machine: parsing code.
This lets llvm-cvtres share it as well.

Making llvm-cvtres depend on llvm-lib seemed a bit strange (it doesn't
need llvm-lib's dependencies on BinaryFormat and BitReader) and I
couldn't find a good place to put this code. Since it's just a few
lines, put it in lib/Object for now.

Differential Revision: https://reviews.llvm.org/D63120

llvm-svn: 363144
2019-06-12 11:32:43 +00:00
Fangrui Song 4ce0a519c1 [ELF][RISCV] Treat R_RISCV_{ADD,SET,SUB}* as link-time constants
R_RISCV_{ADD,SET,SUB}* are used for local label computation.
Add a new RelExpr member R_RISCV_ADD to represent them.

R_RISCV_ADD is treated as a link-time constant because otherwise
R_RISCV_{ADD,SET,SUB}* are not allowed in -pie/-shared mode.
In glibc Scrt1.o, .rela.eh_frame contains such relocations.
Because .eh_frame is not writable, we get this error:

    ld.lld: error: can't create dynamic relocation R_RISCV_ADD32 against symbol: .L0 in readonly segment; recompil object files with -fPIC or pass '-Wl,-z,notext' to allow text relocations in the output
    >>> defined in ..../riscv64-linux-gnu/lib/Scrt1.o

With D63076 and this patch, I can run -pie/-shared programs linked against glibc.

Note llvm-mc cannot currently produce R_RISCV_SET* so they are not tested.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D63183

llvm-svn: 363128
2019-06-12 07:53:06 +00:00
Fangrui Song 11549e5c46 [ELF][PPC64] Don't report "relocation refers to a discarded section" for .toc
Summary:
clang (as of 2019-06-12) / gcc (as of 8.2.1) PPC64 may emit a .rela.toc
which references an embedded switch table in a discarded .rodata/.text
section. The .toc and the .rela.toc are incorrectly not placed in the
comdat.

Technically a relocation from outside the group is not allowed by the ELF spec:

> A symbol table entry with STB_LOCAL binding that is defined relative
> to one of a group's sections, and that is contained in a symbol table
> section that is not part of the group, must be discarded if the group
> members are discarded. References to this symbol table entry from
> outside the group are not allowed.

Don't report errors to work around the bug.

This should fix the ppc64le-lld-multistage-test bot while linking llvm-tblgen:

    ld.lld: error: relocation refers to a discarded section: .rodata._ZNK4llvm3MVT13getSizeInBitsEv
    >>> defined in utils/TableGen/CMakeFiles/llvm-tblgen.dir/CodeGenRegisters.cpp.o
    >>> referenced by CodeGenRegisters.cpp
    >>> utils/TableGen/CMakeFiles/llvm-tblgen.dir/CodeGenRegisters.cpp.o:(.toc+0x0)

Some other PPC specific sections may have similar problems. We can blacklist more
section names when problems occur.

    // A simple program that reproduces the bug.
    // Note .rela.toc (outside the group) references a section symbol (STB_LOCAL) in a group.
    void puts(const char *);
    struct A {
      void foo(int a) {
        switch (a) {
        case 0: puts("0"); break;
        case 1: puts("1"); puts("1"); break;
        case 2: puts("2"); break;
        case 3: puts("3"); puts("4"); break;
        case 4: puts("4"); break;
        case 5: puts("5"); puts("5"); break;
        case 6: puts("6"); break;
        }
      }
      int a;
    };
    void foo(A x) { x.foo(x.a); }

Reviewers: ruiu, sfertile, espindola

Reviewed By: ruiu

Subscribers: emaste, nemanjai, arichardson, kbarton, jsji, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63182

llvm-svn: 363126
2019-06-12 07:35:42 +00:00
Fangrui Song 8a529f3cea Revert "Revert r362867: [ELF][PPC] Simplify {read,write}FromHalf16"
This reverts commit r363060 and restores r362867.

r362867 is innocent. The ppc64le-lld-multistage-test bot failure was due to a clang/gcc .toc bug:

    ld.lld: error: relocation refers to a discarded section: .rodata._ZNK4llvm3MVT13getSizeInBitsEv
    >>> defined in utils/TableGen/CMakeFiles/llvm-tblgen.dir/CodeGenRegisters.cpp.o
    >>> referenced by CodeGenRegisters.cpp
    >>>               utils/TableGen/CMakeFiles/llvm-tblgen.dir/CodeGenRegisters.cpp.o:(.toc+0x0)

It will be worked around by D63182.

llvm-svn: 363124
2019-06-12 06:00:39 +00:00
Amy Huang 9970817c57 Deduplicate S_CONSTANTs in LLD.
Summary: Deduplicate S_CONSTANTS when linking, if they have the same value.

Reviewers: rnk

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63151

llvm-svn: 363089
2019-06-11 18:02:39 +00:00
Nico Weber af6bc65ddf lld-link: Reject more than one resource .obj file
Users are exepcted to pass all .res files to the linker, which then
merges all the resource in all .res files into a tree structure and then
converts the final tree structure to a .obj file with .rsrc$01 and
.rsrc$02 sections and then links that.

If the user instead passes several .obj files containing such resources,
the correct thing to do would be to have custom code to merge the trees
in the resource sections instead of doing normal section merging -- but
link.exe rejects if multiple resource obj files are passed in with
LNK4078, so let lld-link do that too instead of silently writing broken
.rsrc sections in that case.

The only real way to run into this is if users manually convert .res
files to .obj files by running cvtres and then handing the resulting
.obj files to lld-link instead, which in practice likely never happens.

(lld-link is slightly stricter than link.exe now: If link.exe is passed
one .obj file created by cvtres, and a .res file, for some reason it
just emits a warning instead of an error and outputs strange looking
data. lld-link now errors out on mixed input like this.)

One way users could accidentally run into this is the following
scenario: If a .res file is passed to lib.exe, then lib.exe calls
cvtres.exe on the .res file before putting it in the output .lib.
(llvm-lib currently doesn't do this.)
link.exe's /wholearchive seems to only add obj files referenced from the
static library index, but lld-link current really adds all files in the
archive. So if lld-link /wholearchive is used with .lib files produced
by lib.exe and .res files were among the files handed to lib.exe, we
previously silently produced invalid output, but now we error out.

link.exe's /wholearchive semantics on the other hand mean that it
wouldn't load the resource object files from the .lib file at all.
Since this scenario is probably still an unlikely corner case,
the difference in behavior here seems fine -- and lld-link might have to
change to use link.exe's /wholearchive semantics in the future anyways.

Vaguely related to PR42180.

Differential Revision: https://reviews.llvm.org/D63109

llvm-svn: 363078
2019-06-11 15:22:28 +00:00
Fangrui Song 47d77365aa [ELF][RISCV] Add R_RISCV_PC_INDIRECT to isRelExpr()
So that R_RISCV_PCREL_LO12_[IS] are considered as link-time constants in
-pie mode, otherwise there are bogus errors:

    ld.lld: error: can't create dynamic relocation R_RISCV_PCREL_LO12_I against symbol: .L0  in readonly segment; recompile object files with -fPIC or pass '-Wl,-z,notext' to allow text relocations in the output

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D63123

llvm-svn: 363064
2019-06-11 13:39:08 +00:00
Rui Ueyama 963d73ff44 Revert r362867: [ELF][PPC] Simplify {read,write}FromHalf16
This reverts commit r362867 since it seems to have broken
ppc64le-lld-multistage-test bot.

llvm-svn: 363060
2019-06-11 13:00:52 +00:00
Fangrui Song 025a815d75 [ELF] Make the rule to create relative relocations in a writable section stricter
The current rule is loose: `!Sym.IsPreemptible || Expr == R_GOT`.

When the symbol is non-preemptable, this allows absolute relocation
types with smaller numbers of bits, e.g. R_X86_64_{8,16,32}. They are
disallowed by ld.bfd and gold, e.g.

    ld.bfd: a.o: relocation R_X86_64_8 against `.text' can not be used when making a shared object; recompile with -fPIC

This patch:

a) Add TargetInfo::SymbolicRel to represent relocation types that resolve to a
symbol value (e.g. R_AARCH_ABS64, R_386_32, R_X86_64_64).

  As a side benefit, we currently (ab)use GotRel (R_*_GLOB_DAT) to resolve
  GOT slots that are link-time constants. Since we now use Target->SymbolRel
  to do the job, we can remove R_*_GLOB_DAT from relocateOne() for all targets.
  R_*_GLOB_DAT cannot be used as static relocation types.
b) Change the condition to `!Sym.IsPreemptible && Type != Target->SymbolicRel || Expr == R_GOT`.

Some tests are caught by the improved error checking (ld.bfd/gold also
issue errors on them). Many misuse .long where .quad should be used
instead.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D63121

llvm-svn: 363059
2019-06-11 12:59:30 +00:00
Nico Weber dd6019526d Let writeWindowsResourceCOFF() take a TimeStamp parameter
For lld, pass in Config->Timestamp (which is set based on lld's
/timestamp: and /Brepro flags). Since the writeWindowsResourceCOFF()
data is only used in-memory by LLD and the obj's timestamp isn't used
for anything in the output, this doesn't change behavior.

For llvm-cvtres, add an optional /timestamp: parameter, and use the
current behavior of calling time() if the parameter is not passed in.

This doesn't really change observable behavior (unless someone passes
/timestamp: to llvm-cvtres, which wasn't possible before), but it
removes the last unqualified call to time() from llvm/lib, which seems
like a good thing.

Differential Revision: https://reviews.llvm.org/D63116

llvm-svn: 363050
2019-06-11 11:26:50 +00:00
Peter Collingbourne eaf3f56924 ELF: Don't process the partition end marker during combineEhSections().
Otherwise the getPartition() accessor may return an OOB pointer. Found
using _GLIBCXX_DEBUG.

The error is benign (we never dereference the pointer for the end marker)
so this wasn't caught by e.g. the sanitizer bots.

llvm-svn: 363026
2019-06-11 02:54:30 +00:00
Fangrui Song fc2b5c40ae Fix -DBUILD_SHARED_LIBS=on build after r362977
The executable has an undefined reference to lld::Saver, the library
should be explicitly linked.

llvm-svn: 363023
2019-06-11 01:50:58 +00:00
Nico Weber 80571d8ed2 Wrap comment to 80 columns
llvm-svn: 363017
2019-06-11 01:14:23 +00:00
Nico Weber b941fa8821 llvm-lib: Implement /machine: argument
And share some code with lld-link.

While here, also add a FIXME about PR42180 and merge r360150 to llvm-lib.

Differential Revision: https://reviews.llvm.org/D63021

llvm-svn: 363016
2019-06-11 01:13:41 +00:00
Tim Shen 23ee97be05 [LLD] Change FileCheck output file pattern to a temporary file
The previous name "%lib" doesn't trigger any actual replacement. It
creates the file "./tools/lld/test/ELF/%lib.o" in the test directory.

llvm-svn: 362988
2019-06-10 21:39:11 +00:00
Martin Storsjo bb12396f91 [Driver] Look for -m in response files as well
Also expand response files in the MinGW driver.

This should fix PR42135.

Differential Revision: https://reviews.llvm.org/D63024

llvm-svn: 362977
2019-06-10 20:10:10 +00:00
Rui Ueyama 1f73bbbd3a [LLD][COFF] Fix missing MergeChunk::Instances cleanup in COFF::link()
Patch by Erik McClure with a modification to rebase to HEAD.

When calling `COFF::link()` with `CanExitEarly` set to `false`, the
function needs to clean up several global variable caches to ensure that
the next invocation of the function starts from a clean slate. The
`MergeChunk::Instances` cache is missing from this cleanup code, and as
a result will create nondeterministic memory access errors and sometimes
infinite loops due to invalid memory being referenced on the next call
to `COFF::link()`.

This fix simply clears `MergeChunk::Instances` before exiting the function.

An additional review of the COFF library was made to try and find any
other missing global caches, but I was unable to find any other than
`MergeChunk`. Someone more familiar with the global variables might want
to do their own check.

This fix was made to support inNative
<https://github.com/innative-sdk/innative>'s `.wast` script compiler,
which must build multiple incremental builds. It relies on statically
linking LLD because the entire compiler must be a single statically
embeddable library, thus preventing it from being able to call LLD as a
new process.

Differential Revision: https://reviews.llvm.org/D63042

llvm-svn: 362930
2019-06-10 12:16:41 +00:00
Peter Smith 386f3a27db [COFF][X86] Add REQUIRES: x86 to a couple of tests
Fix buildbot failure on native AArch64 buildbot that does not have X86
backend compiled in.

Differential Revision: https://reviews.llvm.org/D63071

llvm-svn: 362926
2019-06-10 10:09:36 +00:00
Fangrui Song 44d908d743 [ELF][RISCV] Parse BFD names elf{32,64}-littleriscv
e.g. glibc libc.so on riscv64 uses `OUTPUT_FORMAT(elf64-littleriscv)`.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D63070

llvm-svn: 362922
2019-06-10 08:09:55 +00:00
Martin Storsjo 6ddd7aa4c3 [ELF] [PPC] Fix a typo from SVN r362721
Apparently no test covers this exact codepath, but GCC produced a
warning about it.

llvm-svn: 362883
2019-06-08 18:26:27 +00:00
Martin Storsjo 4962f9464d [MinGW] Support the -u/--undefined option.
This is implemented by the lld-link option -include:, just like
--require-defined. Contrary to --require-defined, the -u/--undefined
option allows the symbol to remain undefined in the end.

This should fix PR42121.

Differential Revision: https://reviews.llvm.org/D62876

llvm-svn: 362882
2019-06-08 18:26:24 +00:00
Martin Storsjo c02f6bf07f [COFF] Add an lld specific option /includeoptional
This works like /include, but is not fatal if the requested symbol
wasn't found. This allows implementing the GNU ld option -u.

Differential Revision: https://reviews.llvm.org/D62976

llvm-svn: 362881
2019-06-08 18:26:18 +00:00
Fangrui Song 27de3d3950 [ELF][PPC] Simplify {read,write}FromHalf16
I've change the variable names used in PPC64.cpp from "Instr" to "Insn"
because "Insn" is a more common abbreviation for "instruction".

While changing PPC64.cpp relocateOne(), make R_PPC64_ADDR16_LO{_DS}
slightly more efficient by saving a read and a write for the TocOptimize
case.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D63043

llvm-svn: 362867
2019-06-08 05:19:05 +00:00
Reid Kleckner 53cd7406bb [COFF] Fix /export:foo=bar when bar is a weak alias
Summary:
When handling exports from the command line or from .def files, the
linker does a "fuzzy" string lookup to allow finding mangled symbols.
However, when the symbol is re-exported under a new name, the linker has
to transfer the decorations from the exported symbol over to the new
name. This is implemented by taking the mangled symbol that was found in
the object and replacing the original symbol name with the export name.

Before this patch, LLD implemented the fuzzy search by adding an
undefined symbol with the unmangled name, and then during symbol
resolution, checking if similar mangled symbols had been added after the
last round of symbol resolution. If so, LLD makes the original symbol a
weak alias of the mangled symbol. Later, to get the original symbol
name, LLD would look through the weak alias and forward it on to the
import library writer, which copies the symbol decorations. This
approach doesn't work when bar is itself a weak alias, as is the case in
asan. It's especially bad when the aliasee of bar contains the string
"bar", consider "bar_default". In this case, we would end up exporting
the symbol "foo_default" when we should've exported just "foo".

To fix this, don't look through weak aliases to find the mangled name.
Save the mangled name earlier during fuzzy symbol lookup.

Fixes PR42074

Reviewers: mstorsjo, ruiu

Subscribers: thakis, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62984

llvm-svn: 362849
2019-06-07 22:05:12 +00:00
Peter Collingbourne 8cfb14fad6 docs: Update partitioning docs now that the feature is fully landed.
llvm-svn: 362831
2019-06-07 19:23:19 +00:00
Peter Collingbourne 0282898586 ELF: Create synthetic sections for loadable partitions.
We create several types of synthetic sections for loadable partitions, including:
- The dynamic symbol table. This allows code outside of the loadable partitions
  to find entry points with dlsym.
- Creating a dynamic symbol table also requires the creation of several other
  synthetic sections for the partition, such as the dynamic table and hash table
  sections.
- The partition's ELF header is represented as a synthetic section in the
  combined output file, and will be used by llvm-objcopy to extract partitions.

Differential Revision: https://reviews.llvm.org/D62350

llvm-svn: 362819
2019-06-07 17:57:58 +00:00
Peter Smith e208208a31 [ELF][AArch64] Support for BTI and PAC
Branch Target Identification (BTI) and Pointer Authentication (PAC) are
architecture features introduced in v8.5a and 8.3a respectively. The new
instructions have been added in the hint space so that binaries take
advantage of support where it exists yet still run on older hardware. The
impact of each feature is:

BTI: For executable pages that have been guarded, all indirect branches
must have a destination that is a BTI instruction of the appropriate type.
For the static linker, this means that PLT entries must have a "BTI c" as
the first instruction in the sequence. BTI is an all or nothing
property for a link unit, any indirect branch not landing on a valid
destination will cause a Branch Target Exception.

PAC: The dynamic loader encodes with PACIA the address of the destination
that the PLT entry will load from the .plt.got, placing the result in a
subset of the top-bits that are not valid virtual addresses. The PLT entry
may authenticate these top-bits using the AUTIA instruction before
branching to the destination. Use of PAC in PLT sequences is a contract
between the dynamic loader and the static linker, it is independent of
whether the relocatable objects use PAC.

BTI and PAC are independent features that can be combined. So we can have
several combinations of PLT:
- Standard with no BTI or PAC
- BTI PLT with "BTI c" as first instruction.
- PAC PLT with "AUTIA1716" before the indirect branch to X17.
- BTIPAC PLT with "BTI c" as first instruction and "AUTIA1716" before the
  first indirect branch to X17.
    
The use of BTI and PAC in relocatable object files are encoded by feature
bits in the .note.gnu.property section in a similar way to Intel CET. There
is one AArch64 specific program property GNU_PROPERTY_AARCH64_FEATURE_1_AND
and two target feature bits defined:
- GNU_PROPERTY_AARCH64_FEATURE_1_BTI
-- All executable sections are compatible with BTI.
- GNU_PROPERTY_AARCH64_FEATURE_1_PAC
-- All executable sections have return address signing enabled.

Due to the properties of FEATURE_1_AND the static linker can tell when all
input relocatable objects have the BTI and PAC feature bits set. The static
linker uses this to enable the appropriate PLT sequence.
Neither -> standard PLT
GNU_PROPERTY_AARCH64_FEATURE_1_BTI -> BTI PLT
GNU_PROPERTY_AARCH64_FEATURE_1_PAC -> PAC PLT
Both properties -> BTIPAC PLT

In addition to the .note.gnu.properties there are two new command line
options:
--force-bti : Act as if all relocatable inputs had
GNU_PROPERTY_AARCH64_FEATURE_1_BTI and warn for every relocatable object
that does not.
--pac-plt : Act as if all relocatable inputs had
GNU_PROPERTY_AARCH64_FEATURE_1_PAC. As PAC is a contract between the loader
and static linker no warning is given if it is not present in an input.

Two processor specific dynamic tags are used to communicate that a non
standard PLT sequence is being used.
DTI_AARCH64_BTI_PLT and DTI_AARCH64_BTI_PAC.

Differential Revision: https://reviews.llvm.org/D62609

llvm-svn: 362793
2019-06-07 13:00:17 +00:00
Fangrui Song 32742d8f36 [ELF] Delete R_PPC64_CALL_PLT from isRelExpr()
It was added by D46654 but is actually never used.
R_PPC64_CALL_PLT (was: R_PPC_CALL_PLT) is a static link-time constant.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D62994

llvm-svn: 362788
2019-06-07 11:09:33 +00:00
Sam Clegg 53211aa9f1 [lld] Allow args::getInterger to parse args larger than 2^31-1
Differential Revision: https://reviews.llvm.org/D62933

llvm-svn: 362770
2019-06-07 06:05:26 +00:00
Sam Clegg fd54fa5d72 [WebAssembly] Fix for discarded init functions
When a function is excluded via comdat we shouldn't add it to the
final list of init functions.

Differential Revision: https://reviews.llvm.org/D62983

llvm-svn: 362769
2019-06-07 06:00:46 +00:00
Jordan Rupprecht 0629e1252f Revert [ELF] Simplify the condition to create .interp
This reverts r362355 (git commit c78c999a9c)

This causes some internal tests to fail; details provided offthread.

llvm-svn: 362755
2019-06-06 23:23:14 +00:00
Sean Fertile 6a573e3ec3 Revert "Revert "[ELF] Suppress "STT_SECTION symbol should be defined" on .eh_frame, .debug*, .zdebug* and .gcc_except_table""
This reverts commit f49f58527a6d8147524d8d6f2eb1feb70f856292.

llvm-svn: 362744
2019-06-06 20:16:59 +00:00
Sean Fertile 6ba76dd779 Revert "Revert "Reland D61583 [ELF] Error on relocations to STT_SECTION symbols if the sections were discarded""
This reverts commit 729111cf1824159bb4dd331cab8a829eab30313f.

Reverting the previous commit breaks other LLD buildbots.

llvm-svn: 362743
2019-06-06 20:16:53 +00:00
Sean Fertile f1d9b3180e Revert "Reland D61583 [ELF] Error on relocations to STT_SECTION symbols if the sections were discarded"
This reverts commit 5d3b3188f7.

Breaks the PowerPC multi-stage buildbot.

llvm-svn: 362739
2019-06-06 19:34:26 +00:00
Sean Fertile a0a63b2f90 Revert "[ELF] Suppress "STT_SECTION symbol should be defined" on .eh_frame, .debug*, .zdebug* and .gcc_except_table"
This reverts commit dcba4828a9.

This commit builds on  dcba4828a9 which breaks the
multi-staged PowerPC buildbot.

llvm-svn: 362738
2019-06-06 19:34:18 +00:00
Puyan Lotfi 249b721037 Fixing ppc tests: sed -i 's/# REQUIES: ppc/# REQUIRES: ppc/g'
llvm-svn: 362728
2019-06-06 18:05:10 +00:00
Fangrui Song 7ccfdad7ab [PPC32] Support GD/LD/IE/LE TLS models and their relaxations
Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D62940

llvm-svn: 362722
2019-06-06 17:03:10 +00:00
Fangrui Song 82442adfc0 [PPC32] Improve the 32-bit PowerPC port
Many -static/-no-pie/-shared/-pie applications linked against glibc or musl
should work with this patch. This also helps FreeBSD PowerPC64 to migrate
their lib32 (PR40888).

* Fix default image base and max page size.
* Support new-style Secure PLT (see below). Old-style BSS PLT is not
  implemented, so it is not suitable for FreeBSD rtld now because it doesn't
  support Secure PLT yet.
* Support more initial relocation types:
  R_PPC_ADDR32, R_PPC_REL16*, R_PPC_LOCAL24PC, R_PPC_PLTREL24, and R_PPC_GOT16.
  The addend of R_PPC_PLTREL24 is special: it decides the call stub PLT type
  but it should be ignored for the computation of target symbol VA.
* Support GNU ifunc
* Support .glink used for lazy PLT resolution in glibc
* Add a new thunk type: PPC32PltCallStub that is similar to PPC64PltCallStub.
  It is used by R_PPC_REL24 and R_PPC_PLTREL24.

A PLT stub used in -fPIE/-fPIC usually loads an address relative to
.got2+0x8000 (-fpie/-fpic code uses _GLOBAL_OFFSET_TABLE_ relative
addresses).
Two .got2 sections in two object files have different addresses, thus a PLT stub
can't be shared by two object files. To handle this incompatibility,
change the parameters of Thunk::isCompatibleWith to
`const InputSection &, const Relocation &`.

PowerPC psABI specified an old-style .plt (BSS PLT) that is both
writable and executable. Linkers don't make separate RW- and RWE segments,
which causes all initially writable memory (think .data) executable.
This is a big security concern so a new PLT scheme (secure PLT) was developed to
address the security issue.

TLS will be implemented in D62940.

glibc older than ~2012 requires .rela.dyn to include .rela.plt, it can
not handle the DT_RELA+DT_RELASZ == DT_JMPREL case correctly. A hack
(not included in this patch) in LinkerScript.cpp addOrphanSections() to
work around the issue:

    if (Config->EMachine == EM_PPC) {
      // Older glibc assumes .rela.dyn includes .rela.plt
      Add(In.RelaDyn);
      if (In.RelaPlt->isLive() && !In.RelaPlt->Parent)
        In.RelaDyn->getParent()->addSection(In.RelaPlt);
    }

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D62464

llvm-svn: 362721
2019-06-06 17:03:00 +00:00
Sam Clegg 7c663cde14 [WebAssembly] Improve lto/comdat.ll test. NFC.
We were not previously testing the comdat exclusion in bitcode objects
because we were linking two copies of the .bc file and the
`linkonce_odr` linkage type was removing the duplicate `_start` at
the LTO stage.

Now we link an bitcode and non-bitcode version both of which contains a
copy of _start.  We link them in both orders, which means this test will
fail if comdat exclusion is not working correctly in bitcode parsing.

Differential Revision: https://reviews.llvm.org/D62923

llvm-svn: 362650
2019-06-05 21:08:30 +00:00
Dan Gohman ba86f2a22e [WebAssembly] Use Emscripten triples in PIC tests.
With r362638, llc doesn't support -relocation-model=pic with non-Emscripten
triples. Update these tests in lld which use -relocation-model=pic to also
use Emscripten triples.

llvm-svn: 362645
2019-06-05 20:59:20 +00:00
Sam Clegg a282a61ba3 [WebAssembly] Handle object parsing more like the ELF backend
Differential Revision: https://reviews.llvm.org/D62886

llvm-svn: 362626
2019-06-05 17:50:45 +00:00
Sam Clegg 579c8df701 [lld] Explicitly ignore comdat groups when parsing LTO object(s)
Any symbols defined in the LTO object are by definition the ones we
want in the final output so we skip the comdat group checking in those
cases.

This change makes the ELF code more explicit about this and means
that wasm and ELF do this in the same way.

Differential Revision: https://reviews.llvm.org/D62884

llvm-svn: 362625
2019-06-05 17:39:37 +00:00
Peter Smith e12334a0f2 [ELF] Allow reading of more than one FEATURE_1_AND in same object.
Although many relocatable objects will have a single
GNU_PROPERTY_X86_FEATURE_1_AND in the .note.gnu.property section it is
permissible to have more than one, and there are tests in ld.bfd that use
it. The behavior that ld.bfd follows is to set the feature bit for a
relocatable object if any of the GNU_PROPERTY_X86_FEATURE_1_AND
have the feature bit set.

Differential Revision: https://reviews.llvm.org/D62862

llvm-svn: 362591
2019-06-05 09:31:45 +00:00
Rui Ueyama 2057f8366a Read .note.gnu.property sections and emit a merged .note.gnu.property section.
This patch also adds `--require-cet` option for the sake of testing.
The actual feature for IBT-aware PLT is not included in this patch.

This is a part of https://reviews.llvm.org/D59780. Submitting this
first should make it easy to work with a related change
(https://reviews.llvm.org/D62609).

Differential Revision: https://reviews.llvm.org/D62853

llvm-svn: 362579
2019-06-05 03:04:46 +00:00
Alexandre Ganea 4b7bdcd318 [LLD][COFF] Don't take into account the 'age' when looking for PDB type server
The age field is only there to say how many times an OBJ or a PDB was incrementally linked. It shouldn't be used to validate the link between the OBJ and the PDB.

Differential Revision: https://reviews.llvm.org/D62837

llvm-svn: 362572
2019-06-05 02:01:43 +00:00
Thomas Lively b98025a2f7 [WebAssembly] make wasm-ld --verbose show data section startVA and name
Summary:
Make `wasm-ld --verbose` show data section start virtual address and name
as well, instead of just showing the size. This makes it much easier to
track which global variable is in which address when used in conjunction
with `--no-merge-data-sections`.

Patch by Guanzhong Chen

Reviewers: tlively, aheejin, sbc100, ruiu

Reviewed By: sbc100, ruiu

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62834

llvm-svn: 362548
2019-06-04 21:13:41 +00:00
Sam Clegg 8e8ddaa38f [WebAssembly] Add comment as follow-up to rL362276. NFC.
Subscribers: dschuff, jgravelle-google, aheejin, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62824

llvm-svn: 362522
2019-06-04 16:35:23 +00:00
Fangrui Song dcba4828a9 [ELF] Suppress "STT_SECTION symbol should be defined" on .eh_frame, .debug*, .zdebug* and .gcc_except_table
Summary:
With -r or --emit-relocs, we warn `STT_SECTION symbol should be defined`
on relocations to discarded section symbol. This was added as an error
in rLLD319404, but was not so effective before D61583 (it turned the
error to a warning).

Relocations from .eh_frame .debug* .zdebug* .gcc_except_table to
discarded .text are very common and somewhat expected. Don't warn/error
on them. As a reference, ld.bfd has a similar logic in
_bfd_elf_default_action_discarded() to allow these cases.

Delete invalid-undef-section-symbol.test because what it intended to
check is now covered by the updated comdat-discarded-reloc.s

Delete relocatable-eh-frame.s because we allow relocations from
.eh_frame as a special case now.

Reviewers: grimar, phosek, ruiu, espindola

Reviewed By: ruiu

Subscribers: emaste, arichardson, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62840

llvm-svn: 362497
2019-06-04 13:41:29 +00:00
Peter Collingbourne 06f3b094e4 ELF: Introduce a separate bit for tracking whether an output section has ever had an input section added to it. NFCI.
We currently (ab)use the Live bit on output sections to track whether
the section has ever had an input section added to it, and then later
use it during orphan placement. This will conflict with one of my upcoming
partition-related changes that will assign all output sections to a partition
(thus marking them as live) so that they can be added to the correct segment
by the code that creates program headers.

Instead of using the Live bit for this purpose, create a new flag and
start using it to track the property explicitly.

Differential Revision: https://reviews.llvm.org/D62348

llvm-svn: 362444
2019-06-03 20:14:25 +00:00
Reid Kleckner 221e604d6f [PDB] Copy inlinee lines records into the PDB
Summary:
- Fixes inline call frame line table display in windbg.
- Improve llvm-pdbutil to dump extra file ids.
- Warn on unknown subsections so we don't have this kind of bug in the
  future.

Reviewers: inglorion, akhuang, aganea

Subscribers: eraman, zturner, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62701

llvm-svn: 362429
2019-06-03 18:15:38 +00:00
Alexandre Ganea 9c78db6005 Re-land [LLD][COFF] Early load PDB type server files
We need to have all input files ready before doing debuginfo type merging.
This patch is moving the late PDB type server discovery much earlier in the process, when the explicit inputs (OBJs, LIBs) are loaded.
The short term goal is to parallelize type merging.

Differential Revision: https://reviews.llvm.org/D60095

llvm-svn: 362393
2019-06-03 12:39:47 +00:00
George Rimar 3b20ae6c54 [LLD][ELF] - Remove dead code. NFC.
I believe this line was dead after r362356.

llvm-svn: 362367
2019-06-03 09:23:01 +00:00
Fangrui Song 8522d579b8 [ELF][PPC64] Rename some PPC64 ELFv2 specific RelExpr from R_PPC_* to R_PPC64_*
The following abstract relocation types (RelExpr) are PPC64 ELFv2 ABI specific,
not used by PPC32. So rename them to prevent confusion when the PPC32 port is improved.

* R_PPC_CALL R_PPC_CALL_PLT:
  R_PPC_CALL_PLT represents R_PPC64_REL14 and R_PPC64_REL24.
  If the function is not preemptable, R_PPC_CALL_PLT can be optimized to R_PPC_CALL:
  the formula adjusts the symbol VA from the global entry point to the local entry point.
* R_PPC_TOC: represents R_PPC64_TOC.  We don't have a test. Add one to ppc64-relocs.s
  Rename it to R_PPC64_TOCBASE because `@tocbase` is the assembly form.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D62800

llvm-svn: 362359
2019-06-03 06:21:33 +00:00
Fangrui Song ce1534b405 [ELF][PPC64] Don't apply LD->LE relaxation on R_PPC64_GOT_DTPREL16*
In ELF v2 ABI, R_PPC64_GOT_DTPREL16* are not relaxed.

This family of relocation types are used for variables outside of 2GiB
of the TLS block. 2 instructions cannot materialize a DTPREL offset that
is not 32-bit.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D62737

llvm-svn: 362357
2019-06-03 05:41:31 +00:00
Fangrui Song abb7484c31 [ELF] Don't create an output section named `/DISCARD/` if it is assigned to the special phdr `NONE`
Fixes the remaining issue of PR41673 after D61186: with `/DISCARD/ { ... } :NONE`,
we may create an output section named `/DISCARD/`.

Note, if an input section is named `/DISCARD/`, ld.bfd discards it but
lld keeps it. It is probably not worth copying this behavior as it is unrealistic.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D62768

llvm-svn: 362356
2019-06-03 05:34:25 +00:00
Fangrui Song c78c999a9c [ELF] Simplify the condition to create .interp
(1) {gcc,clang} -fuse-ld=bfd -pie -fPIE -nostdlib a.c => .interp created
(2) {gcc,clang} -fuse-ld=lld -pie -fPIE -nostdlib a.c => .interp not created
(3) {gcc,clang} -fuse-ld=lld -pie -fPIE -nostdlib a.c a.so => .interp created

The inconsistency of (2) is due to the condition `!Config->SharedFiles.empty()`.
To make lld behave more like ld.bfd, we could change the condition to:

    Config->HasDynSymTab && !Config->DynamicLinker.empty() && Script->needsInterpSection();

However, that would bring another inconsistency as can be observed with:

(4) {gcc,clang} -fuse-ld=bfd -no-pie -nostdlib a.c => .interp not created

So instead, use `!Config->DynamicLinker.empty() && Script->needsInterpSection()`,
which is both simple and consistent in these cases.

The inconsistency of (4) likely originated from ld.bfd and gold's choice to have a default --dynamic-linker.
Their condition to create .interp is ANDed with (not -shared).
Since lld doesn't have a default --dynamic-linker,
compiler drivers (gcc/clang) don't pass --dynamic-linker for -shared,
and direct ld users are not supposed to specify --dynamic-linker for -shared,
we do not need the condition !Config->Shared.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D62765

llvm-svn: 362355
2019-06-03 05:25:03 +00:00
Rui Ueyama 471f11805f Add --sort-common to the man page.
Differential Revision: https://reviews.llvm.org/D62799

llvm-svn: 362354
2019-06-03 05:11:44 +00:00
Fangrui Song 0a6bababa8 [ELF][MIPS] Delete dead !Sym->isDefined() check in addAbsolute()
llvm-svn: 362314
2019-06-02 02:43:38 +00:00
Fangrui Song bcc0bd7e2a [ELF][test] Reorganize some AArch64 tests
Delete aarch64-got.s because it is covered by aarch64-tls-iele.s
Merge got-aarch64.s into aarch64-fpic-got.s by adding disassembly to the latter
Create aarch64-gnu-ifunc-nonpreemptable to unify aarch64-gnu-ifunc3.s (position-dependent executable) and aarch64-gnu-ifunc-address-pie.s (PIE)
Rename aarch64-got-reloc.s to aarch64-got-weak-undef.s
Add --no-show-raw-insn to llvm-objdump -d RUN lines
Add -pie test to arch64-tls-iele.s
Delete aarch64-tls-pie.s: it is covered by arch64-tls-iele.s and aarch64-tls-le.s
Rename aarch64-copy2.s to aarch64-nopic-plt.s: "copy2" gives false impression that the test is related to copy relocation

llvm-svn: 362294
2019-06-01 11:01:26 +00:00
Sam Clegg 7d4ec5af6c [WebAssembly] Don't export __data_end and __heap_base by default.
These can still be exported via --export if needed.

Differential Revision: https://reviews.llvm.org/D62744

llvm-svn: 362276
2019-05-31 22:51:59 +00:00
Fangrui Song 7477fcd93a [PPC64][test] Delete redundant labels from ppc64-relocs.s
llvm-svn: 362235
2019-05-31 15:41:19 +00:00
Fangrui Song e98baf8631 [ELF] Delete GotEntrySize and GotPltEntrySize
GotEntrySize and GotPltEntrySize were added in D22288. Later, with
the introduction of wordsize() (then Config->Wordsize), they become
redundant, because there is no target that sets GotEntrySize or
GotPltEntrySize to a number different from Config->Wordsize.

Reviewed By: grimar, ruiu

Differential Revision: https://reviews.llvm.org/D62727

llvm-svn: 362220
2019-05-31 10:35:45 +00:00
Fangrui Song 3f29cfd915 [ELF] Replace a dead test in getSymVA() with assert()
Symbols relative to discarded comdat sections are Undefined instead of
Defined now (after D59649 and D61583). The `== &InputSection::Discarded`
test becomes dead. I cannot find a test related to this behavior.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D62725

llvm-svn: 362218
2019-05-31 10:12:22 +00:00
Fangrui Song 750d148e8f [ELF][test] Restore linkerscript/symbol-location.s to test getLinkerScriptLocation()
The test (the only test that checks getLinkerScriptLocation()) deleted
by r358652 can be restored by replacing R_X86_64_PLT32 with
R_X86_64_PC32, and changing -pie to -shared (preemptable). Then, the
symbol will not be a link-time constant and a -fPIC error will be
issued.

llvm-svn: 362207
2019-05-31 08:20:43 +00:00
Thomas Lively 86e73f51d7 [WebAssembly] Improve feature validation error messages
Summary:
Add the names of the input files responsible for each error to the
messages.

Reviewers: sbc100, azakai

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62704

llvm-svn: 362162
2019-05-30 21:57:23 +00:00
J. Ryan Stinnett d45eaf9405 [Docs] Modernize references to macOS
Summary:
This updates all places in documentation that refer to "Mac OS X", "OS X", etc.
to instead use the modern name "macOS" when no specific version number is
mentioned.

If a specific version is mentioned, this attempts to use the OS name at the time
of that version:

* Mac OS X for 10.0 - 10.7
* OS X for 10.8 - 10.11
* macOS for 10.12 - present

Reviewers: JDevlieghere

Subscribers: mgorny, christof, arphaman, cfe-commits, lldb-commits, libcxx-commits, llvm-commits

Tags: #clang, #lldb, #libc, #llvm

Differential Revision: https://reviews.llvm.org/D62654

llvm-svn: 362113
2019-05-30 16:46:22 +00:00
Fangrui Song 0317e46a63 [ELF] Delete dead SHT_NOBITS->SHT_PROGBITS code after r358981
After D60131/r358981, we no longer create SHT_NOBITS sections that may
contain ByteCommand (BYTE, SHORT, LONG, QUAD).

llvm-svn: 362108
2019-05-30 15:52:11 +00:00
Fangrui Song bdaa39ea6c [ELF] De-template addUndefined() and addWrappedSymbols(). NFC
llvm-svn: 362099
2019-05-30 14:50:10 +00:00
Fangrui Song 064ae08e86 [ELF][test] Update znotext-plt-relocations.s to emit R_X86_64_PC32
This is a leftover from r325379.

The intention of this test was to check in a non-pic link, R_X86_64_PC32
to a STT_FUNC created a PLT. However, after the llvm-mc change in
r325569, this code path is no longer exercised. Use the r325379 trick to
keep testing R_X86_64_PC32.

llvm-svn: 362095
2019-05-30 14:16:29 +00:00
Fangrui Song 0526c0cd8e [ELF] Implement Local Dynamic style TLSDESC for x86-64
For the Local Dynamic case of TLSDESC, _TLS_MODULE_BASE_ is defined as a
special TLS symbol that makes:

1) Without relaxation: it produces a dynamic TLSDESC relocation that
computes 0. Adding @dtpoff to access a TLS symbol.
2) With LD->LE relaxation: _TLS_MODULE_BASE_@tpoff = 0 (lowest address in
the TLS block). Adding @tpoff to access a TLS symbol.

For 1), this saves dynamic relocations and GOT slots as otherwise
(General Dynamic) we would create an R_X86_64_TLSDESC and reserve two
GOT slots for each symbol.

Add ElfSym::TlsModuleBase and change the signature of getTlsTpOffset()
to special case _TLS_MODULE_BASE_.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D62577

llvm-svn: 362078
2019-05-30 10:00:20 +00:00
Sam Clegg 56e970d45d [WebAssembly] Move direct call tracking from member to local. NFC.
This data structure is only needed temporarily while symbols are being
created.

This is a followup on rL361678.

Differential Revision: https://reviews.llvm.org/D62548

llvm-svn: 361977
2019-05-29 15:41:08 +00:00
Sam Clegg d506b0a484 [WebAssembly] Fix signatures of undefined function in LTO object which are not called directly.
We recently added special handling for function that are not called
directly but failed to add testing for the LTO case.

See https://reviews.llvm.org/D62153

Differential Revision: https://reviews.llvm.org/D62561

llvm-svn: 361975
2019-05-29 15:36:42 +00:00
Peter Collingbourne 87575f6501 ELF: Don't reuse a thunk in a different loadable partition.
There's no guarantee that the other partition will be loaded, so it
can't be reused.

Differential Revision: https://reviews.llvm.org/D62365

llvm-svn: 361926
2019-05-29 04:06:01 +00:00
Peter Collingbourne ba2816be82 ELF: Add basic partition data structures and behaviours.
This change causes us to read partition specifications from partition
specification sections and split output sections into partitions according
to their reachability from partition entry points.

This is only the first step towards a full implementation of partitions. Later
changes will add additional synthetic sections to each partition so that
they can be loaded independently.

Differential Revision: https://reviews.llvm.org/D60353

llvm-svn: 361925
2019-05-29 03:55:20 +00:00
Peter Collingbourne 31fda09b2d Add IR support, ELF section and user documentation for partitioning feature.
The partitioning feature was proposed here:
http://lists.llvm.org/pipermail/llvm-dev/2019-February/130583.html

This is mostly just documentation. The feature itself will be contributed
in subsequent patches.

Differential Revision: https://reviews.llvm.org/D60242

llvm-svn: 361923
2019-05-29 03:29:01 +00:00
Fangrui Song 719322411c [ELF] Implement General Dynamic style TLSDESC for x86-64
This handles two initial relocation types R_X86_64_GOTPC32_TLSDESC and
R_X86_64_TLSDESC_CALL, as well as the GD->LE and GD->IE relaxations.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D62513

llvm-svn: 361911
2019-05-29 02:03:56 +00:00
Alexandre Ganea ccc1fa5e1d Revert r361842 as it breaks LLDB :: tools/lldb-mi/exec/exec-finish.test
llvm-svn: 361876
2019-05-28 20:57:56 +00:00
Reid Kleckner f612b18720 [COFF] Add ImportChunkThunk, simplify, deduplicate
Removes the isHotPatchable faux-virtual and virtual methods.  Follow-up to
D62362.

Reviewers: aganea

Differential Revision: https://reviews.llvm.org/D62422

llvm-svn: 361851
2019-05-28 17:38:04 +00:00
Alexandre Ganea ebe22a1774 [LLD][COFF] Early load PDB type server files
We need to have all input files ready before doing debuginfo type merging.
This patch is moving the late PDB type server discovery much earlier in the process, when the explicit inputs (OBJs, LIBs) are loaded.
The short term goal is to parallelize type merging.

Differential Revision: https://reviews.llvm.org/D60095

llvm-svn: 361842
2019-05-28 15:35:23 +00:00
Alexandre Ganea 756565d470 Fix 'warning: comparison is always true due to limited range of data type [-Wtype-limits]' with GCC 7.3
llvm-svn: 361840
2019-05-28 15:32:11 +00:00
Fangrui Song 5d3b3188f7 Reland D61583 [ELF] Error on relocations to STT_SECTION symbols if the sections were discarded
This is implemented by creating Undefined (instead of Defined) for such
local STT_SECTION symbols. It allows us to catch errors when there are
relocations to such discarded sections (e.g. in PR41693, ld.bfd and gold
error but we don't). Updated comdat-discarded-error.s checks we emit
friendly error message.

For relocatable-eh-frame.s, ld.lld -r a.o a.o will now error
"STT_SECTION symbol should be defined" because the section .eh_frame
refers to is now an Undefined instead of a Defined.
So I have to change `error()` to `warn()` to retain the output.

rLLD361144 inadvertently enabled the error for --gdb-index
(in LLDDwarfObj<ELFT>::findAux()).

Relocations from .debug_info (not in comdat) to .text.* (in comdat) for
DW_AT_low_pc are common. If an .text.* was discarded, rLLD361144 would error,
which was unexpected. (Note, if we don't error as this patch does,
InputSection::relocateNonAlloc() will resolve such relocations).

llvm-svn: 361830
2019-05-28 14:34:28 +00:00
Nico Weber 833c5abbce Add release note entries for recent typo correction changes
Differential Revision: https://reviews.llvm.org/D62523

llvm-svn: 361824
2019-05-28 14:04:48 +00:00
Haojian Wu 241dcb386e Revert [ELF] Error on relocations to STT_SECTION symbols if the sections were discarded
This reverts r361792 (git commit cfca5095df), the
revision causes link errors internally, will share more details with the
author.

llvm-svn: 361806
2019-05-28 11:21:59 +00:00
Fangrui Song 173a68f1fb [ELF] Replace two addSymbol() call sites with Symbol::resolve(). NFC
If we have a handle of the symbol, insert() called by addSymbol() is
redundant. Just call resolve().

llvm-svn: 361802
2019-05-28 10:12:06 +00:00
Fangrui Song cfca5095df [ELF] Error on relocations to STT_SECTION symbols if the sections were discarded
This is implemented by creating Undefined (instead of Defined) for such
local STT_SECTION symbols. It allows us to catch errors when there are
relocations to such discarded sections (e.g. in PR41693, ld.bfd and gold
error but we don't). Updated comdat-discarded-error.s checks we emit
friendly error message.

For relocatable-eh-frame.s, ld.lld -r a.o a.o will now error
"STT_SECTION symbol should be defined" because the section .eh_frame
refers to is now an Undefined instead of a Defined.
So I have to change `error()` to `warn()` to retain the output.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D61583

llvm-svn: 361792
2019-05-28 06:34:52 +00:00
Rui Ueyama d8f8abbd4a Use SymbolTable::insert() to implement --trace.
Differential Revision: https://reviews.llvm.org/D62381

llvm-svn: 361791
2019-05-28 06:33:06 +00:00
Rui Ueyama 92069605bf Merge ELFFileBase::{initSymtab,parseHeader} as ELFFileBase:init. NFC.
This patch simplifies ELFFile instance initialization by merging
two similar functions into a single function and call it from the
ctor.

llvm-svn: 361789
2019-05-28 05:17:21 +00:00
Rui Ueyama 76737f4d19 Remove elf::createSharedFile and move its code to SharedFile's ctor. NFC.
llvm-svn: 361747
2019-05-27 07:26:13 +00:00
Sam Clegg 59f959ff33 [WebAssembly] Relax signature checking for undefined functions that are not called directly
When function signatures don't match and the undefined function is not
called directly (i.e. only has its address taken) we don't issue a
warning or create a runtime thunk for the undefined function.

Instead in this case we simply use the defined version of the function.
This is possible since checking signatures of dynamic calls happens
at runtime so any invalid usage will still result in a runtime error.

This is needed to allow C++ programs to link without generating
warnings.  Its not uncommon in C++ for vtables to be populated by
function address whee the signature of the function is not known in the
compilation unit.  In this case clang declares the method as void(void)
and relies on the vtable caller casting the data back to the correct
signature.

Fixes: https://bugs.llvm.org/show_bug.cgi?id=40412

Differential Revision: https://reviews.llvm.org/D62153

llvm-svn: 361678
2019-05-24 22:45:08 +00:00
Reid Kleckner a431dd7ae7 [COFF] De-virtualize Chunk and SectionChunk
Shaves another pointer off of SectionChunk, reducing the size from 96 to
88 bytes, down from 144 before I started working on this. Combined with
D62356, this reduced peak memory usage when linking chrome_child.dll
from 713MB to 675MB, or 5%.

Create NonSectionChunk to provide virtual dispatch to the rest of the
chunk types.

Reviewers: ruiu, aganea

Differential Revision: https://reviews.llvm.org/D62362

llvm-svn: 361667
2019-05-24 20:25:40 +00:00
Reid Kleckner 56bee1a90a [COFF] Replace OutputSection* with uint16_t index in Chunk
Shaves another 8 bytes off of SectionChunk, the most commonly allocated
type in LLD.

These indices are only valid after we've assigned chunks to output
sections and removed empty sections, so do that in a new pass.

Reviewers: ruiu, aganea

Differential Revision: https://reviews.llvm.org/D62356

llvm-svn: 361657
2019-05-24 18:25:49 +00:00
Sam Clegg a5ca34e6b3 [WebAssebmly] Add support for --wrap
The code for implementing this features is taken almost verbatim
from the ELF backend.

Fixes: https://bugs.llvm.org/show_bug.cgi?id=41681

Differential Revision: https://reviews.llvm.org/D62380

llvm-svn: 361639
2019-05-24 14:14:25 +00:00
Sam Clegg 7991b68284 [lld] Trace all references with lld --trace-symbol
Previously undefined symbol references were only traced if they were
seen before that definition.

Fixes https://bugs.llvm.org/show_bug.cgi?id=41878

Differential Revision: https://reviews.llvm.org/D61929

llvm-svn: 361636
2019-05-24 13:29:17 +00:00
Sam Clegg 35be7ff80c [WebAssembly] Add support for -emit-relocs
This can be useful for post-link tools and for testing.  Sometimes
it can be useful to produces a regular executable but with relocations
preserved.

Differential Revision: https://reviews.llvm.org/D62378

llvm-svn: 361635
2019-05-24 13:28:27 +00:00
Rui Ueyama 74de6203ef [LLD][COFF] Implement /filealign parameter
Patch by Stefan Schmidt.

This adds the /filealign parameter to lld, which allows to specify the
section alignment in the output file (as it does on Microsoft's
link.exe).

This is required to be able to load dynamically linked libraries on the
original Xbox, where the debugger monitor expects the section alignment
in the file to be the same as in memory.

llvm-svn: 361634
2019-05-24 12:42:36 +00:00
Simon Atanasyan 8362cbe13b [llvm-readobj] Implement GNU-style output for dynamic table
GNU readelf tool prints slightly different dynamic table "header" and
surrounds dynamic tag names by brackets. This patch implements the same
formatting for GNU-style output of the `llvm-readobj`.

LLVM
```
DynamicSection [ (13 entries)
  Tag        Type                 Name/Value
  0x00000006 SYMTAB               0x168
  ...
]
```

GNU
```
Dynamic section at offset 0x1d0 contains 13 entries:
  Tag        Type                 Name/Value
  0x00000006 (SYMTAB)             0x168
  ...
```

Differential Revision: https://reviews.llvm.org/D62256

llvm-svn: 361633
2019-05-24 12:22:53 +00:00
Fangrui Song 7d4a67852d [ELF] Fix a doc typo. NFC
llvm-svn: 361617
2019-05-24 09:53:25 +00:00
Fangrui Song 7f1ff68a16 [ELF] Deleted unused forward declarations. NFC
llvm-svn: 361614
2019-05-24 09:25:47 +00:00
Reid Kleckner 11c141eb68 [COFF] Remove finalizeContents virtual method from Chunk, NFC
This only needs to be done for MergeChunks, so just do that in a
separate pass in the Writer.

This is one small step towards eliminating the vtable in Chunk.

llvm-svn: 361573
2019-05-24 00:02:00 +00:00
Peter Collingbourne ca6a8ae0bf ELF: Remove a comparison against In.EhFrame. NFCI.
This won't work once we have multiple .eh_frame sections.

Differential Revision: https://reviews.llvm.org/D62280

llvm-svn: 361556
2019-05-23 21:30:30 +00:00
Reid Kleckner 14f4ff6e89 [COFF] Move KeepUnique bit from Chunk to SectionChunk, NFC
The KeepUnique bit is used during ICF, which only operates on
SectionChunks, so only SectionChunks need it. This frees up a byte in
Chunk, which I plan to use in a follow-up change.

llvm-svn: 361549
2019-05-23 20:26:41 +00:00
Nico Weber 9b2830b46e lld-link, clang: Treat non-existent input files as possible spellos for option flags
OptTable treats arguments starting with / that aren't a known option
as filenames. This means lld-link's and clang-cl's typo correction for
unknown flags didn't do spell checking for misspelled options that start
with /.

I first tried changing OptTable, but that got pretty messy, see PR41787
comments 2 and 3.

Instead, let lld-link's and clang's (including clang-cl's) "file not
found" diagnostic check if a non-existent file looks like it could be a
mis-spelled option, and if so add a "did you mean" suggestion to the
"file not found" diagnostic.

While here, make formatting of a few diagnostics a bit more
self-consistent.

Fixes PR41787.

Differential Revision: https://reviews.llvm.org/D62276

llvm-svn: 361518
2019-05-23 17:58:33 +00:00
Rui Ueyama f5d9d23905 Simplify InputFile::fetch().
We don't have to return a value from the function. Instead, we can
directly call parseFile from the functions.

llvm-svn: 361478
2019-05-23 10:15:12 +00:00
Rui Ueyama 821a1ac050 Remove LazyObjFile::AddedToLink.
Instead we can just clear a MemoryBuffer so that we cannot get the
same buffer more than once.

llvm-svn: 361477
2019-05-23 10:08:56 +00:00
Sam Clegg 4bce63a0e7 Reland: [WebAssembly] Add __start_/_stop_ symbols for data sections
This is a reland of rL361235.

Fixes https://bugs.llvm.org/show_bug.cgi?id=41565

Differential Revision: https://reviews.llvm.org/D61876

llvm-svn: 361476
2019-05-23 10:06:03 +00:00
Rui Ueyama 7f7d2b2e62 Move code for symbol resolution from SymbolTable.cpp to Symbols.cpp.
My recent commits separated symbol resolution from the symbol table,
so the functions to resolve symbols are now in a somewhat wrong file.
This patch moves it to Symbols.cpp.

The functions are now member functions of the symbol.

This is code move change. I modified function names so that they are
appropriate as member functions, though. No functionality change
intended.

Differential Revision: https://reviews.llvm.org/D62290

llvm-svn: 361474
2019-05-23 09:58:08 +00:00
Rui Ueyama 4254840313 Speed up --start-lib and --end-lib.
--{start,end}-lib give files grouped by the options the archive file
semantics. That is, each object file between them acts as if it were
in an archive file whose sole member is the file.

Therefore, files between --{start,end}-lib are linked to the final
output only if they are needed to resolve some undefined symbols.

Previously, the feature was implemented this way:

 1. We read a symbol table and insert defined symbols to the symbol
    table as lazy symbols.

 2. If an undefind symbol is resolved to a lazy symbol, that lazy
    symbol instantiate ObjFile class for that symbol, which re-insert
    all defined symbols to the symbol table.

So, if an ObjFile is instantiated, defined symbols are inserted to the
symbol table twice. Since inserting long symbol names is not cheap,
there's a room to optimize here.

This patch optimzies it. Now, LazyObjFile remembers symbol handles and
passed them over to a new ObjFile instance, so that the ObjFile
doesn't insert the same strings.

Here is a quick benchmark to link clang. "Original" is the original
lld with unmodified command line options. For "Case 1" and "Case 2", I
extracted all files from archive files and replace .a's in a command
line with .o's wrapped with --{start,end}-lib. I used the original lld
for Case 1" and use this patch for Case 2.

  Original: 5.892
    Case 1: 6.001 (+1.8%)
    Case 2: 5.701 (-3.2%)

So, interestingly, --{start,end}-lib are now faster than the regular
linking scheme with archive files. That's perhaps not too surprising,
though, because for regular archive files, we look up the symbol table
with the same string twice.

Differential Revision: https://reviews.llvm.org/D62188

llvm-svn: 361473
2019-05-23 09:53:30 +00:00
George Rimar 77b4f0abb8 [LLD][ELF] - Improve diagnostic about unrecognized relocations.
This is a minor improvement inspired by https://bugs.llvm.org/show_bug.cgi?id=38303.

A person reported that he observed message complaining about unsupported R_ARM_V4BX:
error: can't create dynamic relocation R_ARM_V4BX against local symbol in readonly segment; recompile object files with -fPIC

But with -z notext he only saw a relocation number, what is not convenient:
error: ../../gfx/cairo/libpixman/src/pixman-arm-neon-asm-bilinear.o:(.text+0x4F0): unrecognized reloc 40

Also, in the error messages we use relocation but not reloc.

With this patch we start to print one of the following messages:
error: file.o: unrecognized relocation Unknown(999)
error: file.o: unrecognized relocation R_X_KNOWN_BY_LLVM_BUT_UNSUPPORTED_BY_LLD_NAME

There is no way to write a test for that I believe.

Differential revision: https://reviews.llvm.org/D62237

llvm-svn: 361472
2019-05-23 09:50:18 +00:00
Sam Clegg b9889bbacb [WebAssembly] Seal imports section before counting imports
Summary:
Before we can assign entries in the function of global index space
we need to know the total number of function and global imports
respectively.

To avoid programmer error this change seals that imports section before
assigned function and global index space.  Any attempt to add an import
after the section is sealed will assert.

The lack this such as check caused  https://reviews.llvm.org/D61876
to be reverted.  I'm also trying to craft a test case the this
failure.

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62240

llvm-svn: 361470
2019-05-23 09:41:03 +00:00
Rui Ueyama 0baaf45be7 Move SymbolTable::addCombinedLTOObject() to LinkerDriver.
Also renames it LinkerDriver::compileBitcodeFiles.

The function doesn't logically belong to SymbolTable. We added this
function to the symbol table because symbol table used to be a
container of input files. This is no longer the case.

Differential Revision: https://reviews.llvm.org/D62291

llvm-svn: 361469
2019-05-23 09:26:27 +00:00
Reid Kleckner ee4e0a2942 Re-land r361206 "[COFF] Store alignment in log2 form, NFC"
The previous patch lost the call to PowerOf2Ceil, which causes LLD to
crash when handling common symbols with a non-power-of-2 size. I tweaked
the existing common.test to make the bsspad16 common symbol be 15 bytes
to add coverage for this case.

llvm-svn: 361426
2019-05-22 20:21:52 +00:00
Simon Atanasyan 74b791b4f7 [mips] Use GNU-style output to make tests smaller. NFC
llvm-svn: 361394
2019-05-22 15:03:52 +00:00
Simon Atanasyan 84f929d00c [mips] Replace multiple `-check-prefix` by single `-check-prefixes`. NFC
llvm-svn: 361393
2019-05-22 15:03:42 +00:00
Rui Ueyama ecf6eb515f Copy symbol length when we replace a symbol.
Symbol's NameSize is computed lazily. Currently, when we replace a symbol,
a cached length value can be discarded. This patch propagates that value.

Differential Revision: https://reviews.llvm.org/D62234

llvm-svn: 361364
2019-05-22 09:19:30 +00:00
Fangrui Song b72b091389 [ELF] Improve error message for relocations to symbols defined in discarded sections
Rather than report "undefined symbol: ", give more informative message
about the object file that defines the discarded section.

In particular, PR41133, if the section is a discarded COMDAT, print the
section group signature and the object file with the prevailing
definition. This is useful to track down some ODR issues.

We need to
* add `uint32_t DiscardedSecIdx` to Undefined for this feature.
* make ComdatGroups public and change its type to DenseMap<CachedHashStringRef, const InputFile *>

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D59649

llvm-svn: 361359
2019-05-22 09:06:42 +00:00
Rui Ueyama 33e74d9f62 Simplify the logic to instantiate Symbols. Should be NFC.
llvm-svn: 361350
2019-05-22 04:56:25 +00:00
Fangrui Song b372259ace [docs] Fix troff macro (.F1 -> .Fl) in ld.lld.1
llvm-svn: 361345
2019-05-22 02:15:25 +00:00
Richard Smith 32591ca4e2 Fix test to put its outputs into the temp directory.
llvm-svn: 361297
2019-05-21 19:41:19 +00:00
Sam Clegg c0a4f45bcb Revert "[WebAssembly] Add __start_/_stop_ symbols for data sections"
This reverts commit 7804dbddcc.

This change broke a bunch of tests of the WebAssembly waterfall.
Will hopefully reland with increased test coverage.

llvm-svn: 361273
2019-05-21 17:16:33 +00:00
Fangrui Song 5ea0d06e81 [ELF] Deleted unused ComdatGroups member variable left by D61854
llvm-svn: 361266
2019-05-21 14:40:38 +00:00
Rui Ueyama d3f27f2bf4 Fix test failure.
I forgot to submit a last-minute change to the last patch.

llvm-svn: 361249
2019-05-21 12:01:16 +00:00
Rui Ueyama 35150bb534 [WebAssembly] Add --reproduce.
--reproduce is a convenient option for debugging. If you invoke lld
with `--reproduce=repro.tar`, it creates `repro.tar` with all input
files and the command line options given to the linker, so that it is
very easy to run lld with the exact same inputs.

ELF and Windows lld have this option.

This patch add that option to lld/wasm.

Differential Revision: https://reviews.llvm.org/D62170

llvm-svn: 361244
2019-05-21 11:52:14 +00:00
Sam Clegg 7804dbddcc [WebAssembly] Add __start_/_stop_ symbols for data sections
Fixes https://bugs.llvm.org/show_bug.cgi?id=41565

Differential Revision: https://reviews.llvm.org/D61876

llvm-svn: 361236
2019-05-21 10:07:30 +00:00
Sam Clegg 8fcf012693 [WebAssembly] Refactor synthetic sections and relocation processing. NFC.
Major refactor to better match the structure of the ELF linker.

- Split out relocation processing into scanRelocations
- Split out synthetic sections into their own classes.

Differential Revision: https://reviews.llvm.org/D61811

llvm-svn: 361233
2019-05-21 09:13:09 +00:00
Fangrui Song ecf4c9e13c [ELF] Don't advance position in a memory region when assigning to the Dot
For memory5.test, ld.bfd appears to ignore `. += 0x2000;`, so the test was testing
a wrong behavior. After deleting the code added in rLLD336335, we match ld.bfd and thus fix PR41357.

PR37836 (memory4.test) seems to have been fixed by another change.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D62177

llvm-svn: 361228
2019-05-21 08:21:44 +00:00
Fangrui Song 547e3e930c [ELF] Error on relocations to local undefined symbols
For a reference to a local symbol, ld.bfd and gold error if the symbol
is defined in a discarded section but accept it if the symbol is
undefined. This inconsistent behavior seems unnecessary for us (it
probably makes sense for them as they differentiate local/global
symbols, the error would mean more code).

Catch such errors. Symbol index 0 may be used by marker relocations,
e.g. R_*_NONE R_ARM_V4BX. Don't error on them.

The difference from D61563 (which caused msan failure) is we don't call
Sym.computeBinding() on local symbols - VersionId is uninitialized.

llvm-svn: 361213
2019-05-21 02:38:11 +00:00
Nico Weber 67510fac36 Revert r361206 "[COFF] Store alignment in log2 form, NFC"
Makes the linker crash when linking nasm.exe.

llvm-svn: 361212
2019-05-21 02:06:59 +00:00
Reid Kleckner 1a5cc629de [COFF] Store alignment in log2 form, NFC
Summary:
Valid section or chunk alignments are powers of 2 in the range [1,
8192]. These can be stored more canonically in log2 form to free up some
bits in Chunk. Combined with D61696, SectionChunk gets 8 bytes smaller.

Reviewers: ruiu, aganea

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D61698

llvm-svn: 361206
2019-05-20 22:57:52 +00:00
Tiancong Wang a5d8d01d6f [ELF][Driver] Fix precedence of symbol ordering file and CGProfile
This patch is a fix for https://bugs.llvm.org/show_bug.cgi?id=41804.
We try to solve the precedence of user-specified symbol ordering file and C3 ordering provided as call graph. It deals with two case:
(1) When both --symbol-ordering-file=<file> and --call-graph-order-file=<file> are present, whichever flag comes later will take precedence.
(2) When only --symbol-ordering-file=<file> is present, it takes precedence over implicit call graph (CGProfile) generated by CGProfilePass enabled in new pass manager.

llvm-svn: 361190
2019-05-20 19:13:34 +00:00
Tiancong Wang af4219adf5 Test commit, add an empty line.
llvm-svn: 361186
2019-05-20 18:46:25 +00:00
Fangrui Song 055906e1e5 [ELF] -z combreloc: sort dynamic relocations by (!is_relative,symbol_index,r_offset)
We currently sort dynamic relocations by (!is_relative,symbol_index).
Add r_offset as the third key. This makes `readelf -r` debugging easier
(relocations to the same symbol are ordered by r_offset).

Refactor the test combreloc.s (renamed from combrelocs.s) to check
R_X86_64_RELATIVE, and delete --expand-relocs.

The difference from the reverted D61477 is that we keep !is_relative as
the first key. In local dynamic TLS model, DTPMOD (e.g.
R_ARM_TLS_DTPMOD32 R_X86_64_DTPMOD and R_PPC{,64}_DTPMOD) may use 0 as
the symbol index.

Reviewed By: grimar

Differential Revision: https://reviews.llvm.org/D62141

llvm-svn: 361164
2019-05-20 15:25:01 +00:00
Dmitri Gribenko 0429fddc9d Revert "[ELF] Error on relocations to local undefined symbols"
This reverts commit r361144.  It causes a use-of-uninitialized-value in
maybeReportUndefined at llvm/tools/lld/ELF/Relocations.cpp:682, as
detected by MemorySanitizer when local-undefined-symbol.s test is run.

llvm-svn: 361162
2019-05-20 15:04:08 +00:00
Dmitri Gribenko a2fbe2bcda Revert "[ELF] -z combreloc: sort dynamic relocations by (symbol_index,r_offset)"
This reverts commit r361125.  This linker change breaks shared libraries
in some subtle way on x86_64.  (Specifically, gold segfaults when
loading the LLVMgold.so plugin linked with lldb with this patch.)

llvm-svn: 361150
2019-05-20 13:05:55 +00:00
Fangrui Song 2109572464 [ELF] Fix getRelocTargetVA formulae of R_TLS and R_NEG_TLS
For R_TLS:
1) Delete Sym.isTls() . The assembler ensures the symbol is STT_TLS.
   If not (the input is broken), we would crash (dereferencing null Out::TlsPhdr).
2) Change Sym.isUndefWeak() to Sym.isUndefined(), otherwise with --noinhibit-exec
   we would still evaluate the symbol and crash.
3) Return A if the symbol is undefined. This is PR40570.
   The case is probably unrealistic but returning A matches R_ABS and the
   behavior of several dynamic loaders.

R_NEG_TLS is obsoleted Sun TLS we don't fully support, but
R_RELAX_TLS_GD_TO_LE_NEG is still used by GD->LE relaxation (subl $var@tpoff,%eax).

They should add the addend. Unfortunately I can't test it as compilers don't seem to generate non-zero implicit addends.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D62098

llvm-svn: 361146
2019-05-20 11:47:31 +00:00
Fangrui Song 7c7425483a [ELF] Error on relocations to local undefined symbols
For a reference to a local symbol, ld.bfd and gold error if the symbol
is defined in a discarded section but accept it if the symbol is
undefined. This inconsistent behavior seems unnecessary for us (it
probably makes sense for them as they differentiate local/global
symbols, the error would mean more code).

Weaken the condition to getSymbol(Config->IsMips64EL) == 0 to catch such
errors. The symbol index can be 0 (e.g. R_*_NONE R_ARM_V4BX) and we shouldn't error on them.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D61563

llvm-svn: 361144
2019-05-20 11:25:55 +00:00
Fangrui Song 63514556c4 [MIPS] Update mips-abs-got.s to not use .reloc
As Simon Atanasyan suggested in D61563

llvm-svn: 361142
2019-05-20 11:17:02 +00:00
Yvan Roux bc07278e02 [ELF] Fix tests from r361013 on ARM/AARch64 bots.
llvm-svn: 361128
2019-05-20 08:51:39 +00:00
Fangrui Song 9f1a6de631 [ELF] -z combreloc: sort dynamic relocations by (symbol_index,r_offset)
Fixes PR41692.

We currently sort dynamic relocations by (!is_relative,symbol_index).
Change it to (symbol_index,r_offset). We still place relative
relocations first because R_*_RELATIVE are the only dynamic relocations
with 0 symbol index (except on MIPS, which doesn't use DT_REL[A]COUNT
anyway).

This makes `readelf -r` debugging easier (relocations to the same symbol
are ordered by r_offset).

Refactor the test combreloc.s (renamed from combrelocs.s) to check
R_X86_64_RELATIVE, and delete --expand-relocs.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D61477

llvm-svn: 361125
2019-05-20 07:22:55 +00:00
Rui Ueyama faf541e1e1 Make replaceSymbol a member function of Symbol.
This is a mechanical rewrite of replaceSymbol(A, B) to A->replace(B).
I also added a comment to Symbol::replace().

Technically this change is not necessary, but this change makes code a
bit more concise.

Differential Revision: https://reviews.llvm.org/D62117

llvm-svn: 361123
2019-05-20 03:36:33 +00:00
Fangrui Song a6720e7407 [ELF] Copy IsPreemptible in replaceSymbol()
Otherwise, we may set IsPreemptible (e.g. --dynamic-list) then clear it
(in replaceCommonSymbols()).

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D62107

llvm-svn: 361122
2019-05-20 02:07:03 +00:00
Michael Liao 63621832da Suppress false-positive GCC -Wreturn-type warning.
llvm-svn: 361094
2019-05-18 06:35:47 +00:00
Martin Storsjo 5fab538e2a [MinGW] Set the right updated option help for the updated pdb option. NFC
I forgot to amend this change before committing it in SVN r361014, this
is what was agreed upon in the review.

llvm-svn: 361093
2019-05-18 04:20:31 +00:00
Fangrui Song ed2ad77ccb [ARM][AArch64] Revert Android Bionic PT_TLS overaligning hack
This reverts D53906.

D53906 increased p_align of PT_TLS on ARM/AArch64 to 32/64 to make the
static TLS layout compatible with Android Bionic's ELF TLS. However,
this may cause glibc ARM/AArch64 programs to crash (see PR41527).

The faulty PT_TLS in the executable satisfies p_vaddr%p_align != 0. The
remainder is normally 0 but may be non-zero with the hack in place. The
problem is that we increase PT_TLS's p_align after OutputSections'
addresses are fixed (assignAddress()). It is possible that
p_vaddr%old_p_align = 0 while p_vaddr%new_p_align != 0.

For a thread local variable defined in the executable, lld computed TLS
offset (local exec) is different from glibc computed TLS offset from
another module (initial exec/generic dynamic). Note: PR41527 said the
bug affects initial exec but actually generic dynamic is affected as
well.

(glibc is correct in that it compute offsets that satisfy
`offset%p_align == p_vaddr%p_align`, which is a basic ELF requirement.
This hack appears to work on FreeBSD rtld, musl<=1.1.22, and Bionic, but
that is just because they (and lld) incorrectly compute offsets that
satisfy `offset%p_align = 0` instead.)

Android developers are fine to revert this patch, carry this patch in
their tree before figuring out a long-term solution (e.g. a dummy .tdata
with sh_addralign=64 sh_size={0,1} in crtbegin*.o files. The overhead is
now insignificant after D62059).

Reviewed By: rprichard, srhines

Differential Revision: https://reviews.llvm.org/D62055

llvm-svn: 361090
2019-05-18 03:16:00 +00:00
Fangrui Song 898896836d [ELF][X86] Fix R_RELAX_TLS_GD_TO_LE_NEG and R_NEG_TLS after D62059
After D62059, we don't align p_memsz of PT_TLS to p_align. The
getRelocTargetVA formula should align it instead.

It becomes clear that R_NEG_TLS and R_TLS are opposite from each other.

In i386-tls-le-align.s, I put ret after call ___tls_get_addr@plt as
otherwise ld.bfd would reject the relaxation:
TLS transition from R_386_TLS_GD to R_386_TLS_LE_32 against `a' at 0x3 in section `.text' failed

llvm-svn: 361088
2019-05-18 01:58:40 +00:00
Fangrui Song db5cb0fce7 [ELF] Add {i386,x86-64}-tls-le-align.s to test TP offsets for TLS Variant 2
I forgot to add them in rLLD361084. I made another mistake, rLLD361084 fixed Variant 2, not Variant 1.

llvm-svn: 361085
2019-05-18 00:57:30 +00:00
Fangrui Song 348731aeed [ELF] Fix TP offset of TLS Variant I after D62059
As Ryan Prichard pointed out, after D62059, the TP offset is incorrect.

Add x86-64-tls-le-align.s to check this.  Better formulae for both
variants should take p_vaddr%p_align into account (offset%p_align =
p_vaddr%p_align is a basic ELF requirement), but I can't find a way to
test the behavior.

llvm-svn: 361084
2019-05-18 00:43:10 +00:00
Russell Gallop 3a02b12439 Fix tests from r361013 on X86 bots.
llvm-svn: 361041
2019-05-17 15:38:01 +00:00
Fangrui Song f3a3b93f54 [ELF] -r: fix R_*_NONE to section symbols on Elf*_Rel targets
On Elf*_Rel targets, for a relocation to a section symbol, an R_ABS is
added which will be used by relocateOne() to compute the implicit
addend.

Addends of R_*_NONE should be ignored, so don't emit an R_ABS.

This fixes crashes on X86 and ARM because their relocateOne() do not
handle R_*_NONE.

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D62052

llvm-svn: 361036
2019-05-17 14:11:03 +00:00
Fangrui Song f3dccc64af [ELF] Don't align PT_TLS's p_memsz
The code was added in r252352, probably to address some layout issues.
Actually PT_TLS's p_memsz doesn't need to be aligned on either variant.
ld.bfd doesn't do that.

In case of larger alignment (e.g. 64 for Android Bionic on AArch64, see
D62055), this may make the overhead smaller.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D62059

llvm-svn: 361029
2019-05-17 12:48:53 +00:00
Martin Storsjo 6ff6a8f656 [MinGW] Include --enable-auto-import in the help listing
Libtool concludes that the linker doesn't support shared libraries,
unless this flag is listed in the output of --help.

Differential Revision: https://reviews.llvm.org/D62053

llvm-svn: 361017
2019-05-17 11:07:46 +00:00
Martin Storsjo 6863dfaa21 [MinGW] Implement the -v and --version flags for the MinGW driver
Differential Revision: https://reviews.llvm.org/D62030

llvm-svn: 361016
2019-05-17 11:07:42 +00:00
Martin Storsjo 9ae0d222dc [MinGW] Implement --help for the MinGW driver
Differential Revision: https://reviews.llvm.org/D62029

llvm-svn: 361015
2019-05-17 11:07:38 +00:00
Martin Storsjo 2c52ddf31f [MinGW] Allow requesting PDB output without giving a file name
When integrating PDB output in mingw targeting build systems, it
might be a lot of extra work to specify unique file names for
the pdb output. Therefore allow omitting the actual file name
and let it implicitly be the same name as the linker output, with
a pdb extension.

As the current form of the pdb option takes a separate parameter value,
e.g. "-pdb out.pdb", it is impractical to leave out the parameter value.

Therefore, introduce a second syntax for the option, with an equals
sign, like -pdb=out.pdb, where the value easily can be omitted.

The form -pdb= for requesting pdb files with an implicit name should
work fine, even though it looks a bit unconventional in that form.

Differential Revision: https://reviews.llvm.org/D62004

llvm-svn: 361014
2019-05-17 11:07:33 +00:00
Fangrui Song ef9b8e03fd [ELF][test] Reorganize some R_*_NONE tests
Change R_{386,AARCH64}_NONE yaml2obj tests/icf10.test to use assembly

Add relocation-none-{arm,x86_64}.s.
  Check the referenced section survives under --gc-sections.
  Check -r copies R_X86_64_NONE R_AARCH64_NONE. (Elf*_Rel arches currently have a bug)
  Delete the dtrace tests as they are covered by the R_X86_64_NONE test.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D62051

llvm-svn: 361013
2019-05-17 10:44:05 +00:00
Ben Dunbobbin 1d16515fb4 [ELF] Implement Dependent Libraries Feature
This patch implements a limited form of autolinking primarily designed to allow
either the --dependent-library compiler option, or "comment lib" pragmas (
https://docs.microsoft.com/en-us/cpp/preprocessor/comment-c-cpp?view=vs-2017) in
C/C++ e.g. #pragma comment(lib, "foo"), to cause an ELF linker to automatically
add the specified library to the link when processing the input file generated
by the compiler.

Currently this extension is unique to LLVM and LLD. However, care has been taken
to design this feature so that it could be supported by other ELF linkers.

The design goals were to provide:

- A simple linking model for developers to reason about.
- The ability to to override autolinking from the linker command line.
- Source code compatibility, where possible, with "comment lib" pragmas in other
  environments (MSVC in particular).

Dependent library support is implemented differently for ELF platforms than on
the other platforms. Primarily this difference is that on ELF we pass the
dependent library specifiers directly to the linker without manipulating them.
This is in contrast to other platforms where they are mapped to a specific
linker option by the compiler. This difference is a result of the greater
variety of ELF linkers and the fact that ELF linkers tend to handle libraries in
a more complicated fashion than on other platforms. This forces us to defer
handling the specifiers to the linker.

In order to achieve a level of source code compatibility with other platforms
we have restricted this feature to work with libraries that meet the following
"reasonable" requirements:

1. There are no competing defined symbols in a given set of libraries, or
   if they exist, the program owner doesn't care which is linked to their
   program.
2. There may be circular dependencies between libraries.

The binary representation is a mergeable string section (SHF_MERGE,
SHF_STRINGS), called .deplibs, with custom type SHT_LLVM_DEPENDENT_LIBRARIES
(0x6fff4c04). The compiler forms this section by concatenating the arguments of
the "comment lib" pragmas and --dependent-library options in the order they are
encountered. Partial (-r, -Ur) links are handled by concatenating .deplibs
sections with the normal mergeable string section rules. As an example, #pragma
comment(lib, "foo") would result in:

.section ".deplibs","MS",@llvm_dependent_libraries,1
         .asciz "foo"

For LTO, equivalent information to the contents of a the .deplibs section can be
retrieved by the LLD for bitcode input files.

LLD processes the dependent library specifiers in the following way:

1. Dependent libraries which are found from the specifiers in .deplibs sections
   of relocatable object files are added when the linker decides to include that
   file (which could itself be in a library) in the link. Dependent libraries
   behave as if they were appended to the command line after all other options. As
   a consequence the set of dependent libraries are searched last to resolve
   symbols.
2. It is an error if a file cannot be found for a given specifier.
3. Any command line options in effect at the end of the command line parsing apply
   to the dependent libraries, e.g. --whole-archive.
4. The linker tries to add a library or relocatable object file from each of the
   strings in a .deplibs section by; first, handling the string as if it was
   specified on the command line; second, by looking for the string in each of the
   library search paths in turn; third, by looking for a lib<string>.a or
   lib<string>.so (depending on the current mode of the linker) in each of the
   library search paths.
5. A new command line option --no-dependent-libraries tells LLD to ignore the
   dependent libraries.

Rationale for the above points:

1. Adding the dependent libraries last makes the process simple to understand
   from a developers perspective. All linkers are able to implement this scheme.
2. Error-ing for libraries that are not found seems like better behavior than
   failing the link during symbol resolution.
3. It seems useful for the user to be able to apply command line options which
   will affect all of the dependent libraries. There is a potential problem of
   surprise for developers, who might not realize that these options would apply
   to these "invisible" input files; however, despite the potential for surprise,
   this is easy for developers to reason about and gives developers the control
   that they may require.
4. This algorithm takes into account all of the different ways that ELF linkers
   find input files. The different search methods are tried by the linker in most
   obvious to least obvious order.
5. I considered adding finer grained control over which dependent libraries were
   ignored (e.g. MSVC has /nodefaultlib:<library>); however, I concluded that this
   is not necessary: if finer control is required developers can fall back to using
   the command line directly.

RFC thread: http://lists.llvm.org/pipermail/llvm-dev/2019-March/131004.html.

Differential Revision: https://reviews.llvm.org/D60274

llvm-svn: 360984
2019-05-17 03:44:15 +00:00
Rui Ueyama bbf154cf9c Move symbol resolution code out of SymbolTable class.
This is the last patch of the series of patches to make it possible to
resolve symbols without asking SymbolTable to do so.

The main point of this patch is the introduction of
`elf::resolveSymbol(Symbol *Old, Symbol *New)`. That function resolves
or merges given symbols by examining symbol types and call
replaceSymbol (which memcpy's New to Old) if necessary.

With the new function, we have now separated symbol resolution from
symbol lookup. If you already have a Symbol pointer, you can directly
resolve the symbol without asking SymbolTable to do that.

Now that the nice abstraction become available, I can start working on
performance improvement of the linker. As a starter, I'm thinking of
making --{start,end}-lib faster.

--{start,end}-lib is currently unnecessarily slow because it looks up
the symbol table twice for each symbol.

 - The first hash table lookup/insertion occurs when we instantiate a
   LazyObject file to insert LazyObject symbols.

 - The second hash table lookup/insertion occurs when we create an
   ObjFile from LazyObject file. That overwrites LazyObject symbols
   with Defined symbols.

I think it is not too hard to see how we can now eliminate the second
hash table lookup. We can keep LazyObject symbols in Step 1, and then
call elf::resolveSymbol() to do Step 2.

Differential Revision: https://reviews.llvm.org/D61898

llvm-svn: 360975
2019-05-17 01:55:20 +00:00
Bob Haarman 5ff1eb6418 Revert r358069 "Discard debuginfo for object files empty after GC"
The change broke some scenarios where debug information is still
needed, although MarkLive cannot see it, including the
Chromium/Android build. Reverting to unbreak that build.

llvm-svn: 360955
2019-05-16 23:33:06 +00:00
Sam Clegg d029bf0f8c [WebAssembly] Move code and data section generation to finalizeContent. NFC.
Previously these sections were being generated during their
constructors.  This moves the work to finalizeContent, and also does
the same for the relocation sections because their contents depends
on the final layout too.

This change is part of a larger refactor to how we deal with synthetic
sections: https://reviews.llvm.org/D61811

Differential Revision: https://reviews.llvm.org/D61971

llvm-svn: 360941
2019-05-16 21:36:06 +00:00
Sam Clegg 1a53ff2a13 [WebAssembly] Don't generate empty type sections.
Differential Revision: https://reviews.llvm.org/D61991

llvm-svn: 360940
2019-05-16 21:22:43 +00:00
Yvan Roux 671fc5f3f4 [lld-link] Add missing "REQUIRES: x86" to COFF/lib-module-asm.ll test.
This should fix ARM bots.

llvm-svn: 360875
2019-05-16 11:29:30 +00:00
Igor Kudrin 261a1bc129 Add missing "REQUIRES: x86" to the lto/irmover-warning.ll test.
llvm-svn: 360866
2019-05-16 09:04:52 +00:00
Igor Kudrin 4669cf2750 [LTO] Improve readability of module IDs
Module IDs can appear in diagnostic messages.
This patch adds some auxiliary symbols to improve their readability.

Differential Revision: https://reviews.llvm.org/D61857

llvm-svn: 360858
2019-05-16 05:23:25 +00:00
Rui Ueyama 54ee6df247 Pemove SymbolTable::addBitcode as it is redundant.
Differential Revision: https://reviews.llvm.org/D61897

llvm-svn: 360846
2019-05-16 03:54:50 +00:00
Rui Ueyama d668873bfe Consistently return `Symbol *` from SymbolTable's add-family functions.
llvm-svn: 360845
2019-05-16 03:54:41 +00:00
Rui Ueyama 943cd00580 De-template parseFile() and SymbolTable's add-family functions.
Differential Revision: https://reviews.llvm.org/D61896

llvm-svn: 360844
2019-05-16 03:45:13 +00:00
Rui Ueyama 5c073a94f9 Introduce CommonSymbol.
Previously, we handled common symbols as a kind of Defined symbol,
but what we were doing for common symbols is pretty different from
regular defined symbols.

Common symbol and defined symbol are probably as different as shared
symbol and defined symbols are different.

This patch introduces CommonSymbol to represent common symbols.
After symbols are resolved, they are converted to Defined symbols
residing in a .bss section.

Differential Revision: https://reviews.llvm.org/D61895

llvm-svn: 360841
2019-05-16 03:29:03 +00:00
Rui Ueyama 7d4761928e Simplify SymbolTable::add{Defined,Undefined,...} functions.
SymbolTable's add-family functions have lots of parameters because
when they have to create a new symbol, they forward given arguments
to Symbol's constructors. Therefore, the functions take at least as
many arguments as their corresponding constructors.

This patch simplifies the add-family functions. Now, the functions
take a symbol instead of arguments to construct a symbol. If there's
no existing symbol, a given symbol is memcpy'ed to the symbol table.
Otherwise, the functions attempt to merge the existing and a given
new symbol.

I also eliminated `CanOmitFromDynSym` parameter, so that the functions
take really one argument.

Symbol classes are trivially constructible, so looks like constructing
them to pass to add-family functions is as cheap as passing a lot of
arguments to the functions. A quick benchmark showed that this patch
seems performance-neutral.

This is a preparation for
http://lists.llvm.org/pipermail/llvm-dev/2019-April/131902.html

Differential Revision: https://reviews.llvm.org/D61855

llvm-svn: 360838
2019-05-16 02:14:00 +00:00
Sam Clegg e7ab59eda9 [ELF] Fix typo in header guard. NFC.
llvm-svn: 360832
2019-05-16 00:45:50 +00:00
Sam Clegg 5e6ea24497 [lld] Remove 2>&1 from --trace-symbol tests
The tracing goes to stdout so this is not needed.

Also remove the "not" from the final check in ELF/trace-symbols.s.
According the comment the check is that we don't crash, so we should
be checking for success here. Previously this step is error'ing with
undefined symbols because it didn't include all the needed objects.

Differential Revision: https://reviews.llvm.org/D61928

llvm-svn: 360794
2019-05-15 19:01:51 +00:00
Sam Clegg 697f2149f1 [WebAssembly] LTO: Honor comdat groups when loading bitcode files
But don't apply comdat groups when loading the LTO object files.
This is basically the same logic used by the ELF linker.

Differential Revision: https://reviews.llvm.org/D61924

llvm-svn: 360782
2019-05-15 16:03:28 +00:00
Fangrui Song e041d15f5e [LLD][ELF] Add the -z ifunc-noplt option
Patch by Mark Johnston!

Summary:
When the option is configured, ifunc calls do not go through the PLT;
rather, they appear as regular function calls with relocations
referencing the ifunc symbol, and the resolver is invoked when
applying the relocation.  This is intended for use in freestanding
environments where text relocations are permissible and is incompatible
with the -z text option.  The option is motivated by ifunc usage in the
FreeBSD kernel, where ifuncs are used to elide CPU feature flag bit
checks in hot paths.  Instead of replacing the cost of a branch with that
of an indirect function call, the -z ifunc-noplt option is used to ensure
that ifunc calls carry no hidden overhead relative to normal function
calls.

Test Plan:
I added a couple of regression tests and tested the FreeBSD kernel
build using the latest lld sources.

To demonstrate the effects of the change, I used a micro-benchmark
which results in frequent invocations of a FreeBSD kernel ifunc.  The
benchmark was run with and without IBRS enabled, and with and without
-zifunc-noplt configured.  The observed speedup is small and consistent,
and is significantly larger with IBRS enabled:

https://people.freebsd.org/~markj/ifunc-noplt/noibrs.txt
https://people.freebsd.org/~markj/ifunc-noplt/ibrs.txt

Reviewed By: ruiu, MaskRay

Differential Revision: https://reviews.llvm.org/D61613

llvm-svn: 360685
2019-05-14 15:25:21 +00:00
Fangrui Song ed4dbe6326 [ELF] --gdb-index: fix SIGSEGV when a DWARFAddressRange has invalid SectionIndex
See D61891: llvm had a bug that might create invalid (DW_AT_low_pc,DW_AT_high_pc) pairs or range list entries due to missing DW_AT_addr_base.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D61889

llvm-svn: 360679
2019-05-14 14:41:20 +00:00
Rui Ueyama 2dd5283d2a Move SymbolTable::addFile to InputFiles.cpp.
The symbol table used to be a container of vectors of input files,
but that's no longer the case because the vectors are moved out of
SymbolTable and are now global variables.

Therefore, addFile doesn't have to belong to any class. This patch
moves the function out of the class.

This patch is a preparation for my RFC [1].

[1] http://lists.llvm.org/pipermail/llvm-dev/2019-April/131902.html

Differential Revision: https://reviews.llvm.org/D61854

llvm-svn: 360666
2019-05-14 12:03:13 +00:00
Fangrui Song e1cb2c0f40 [Object] Change ObjectFile::getSectionContents to return Expected<ArrayRef<uint8_t>>
Change
std::error_code getSectionContents(DataRefImpl, StringRef &) const;
to
Expected<ArrayRef<uint8_t>> getSectionContents(DataRefImpl) const;

Many object formats use ArrayRef<uint8_t> as the underlying type, which
is generally better than StringRef to represent binary data, so change
the type to decrease the number of type conversions.

Reviewed By: ruiu, sbc100

Differential Revision: https://reviews.llvm.org/D61781

llvm-svn: 360648
2019-05-14 04:22:51 +00:00
Sam Clegg 0b13ca2f5e [WebAssembly] Refactor relocation processing. NFC.
This is the remaining NFC part of https://reviews.llvm.org/D61539 which
was reverted.

Differential Revision: https://reviews.llvm.org/D61800

llvm-svn: 360598
2019-05-13 16:42:52 +00:00
Peter Smith 4e21c770ec [ELF] Full support for -n (--nmagic) and -N (--omagic) via common page
The -n (--nmagic) disables page alignment, and acts as a -Bstatic
The -N (--omagic) does what -n does but also marks the executable segment as
writeable. As page alignment is disabled headers are not allocated unless
explicit in the linker script.

To disable page alignment in LLD we choose to set the page sizes to 1 so
that any alignment based on the page size does nothing. To set the
Target->PageSize to 1 we implement -z common-page-size, which has the side
effect of allowing the user to set the value as well.

Setting the page alignments to 1 does mean that any use of
CONSTANT(MAXPAGESIZE) or CONSTANT(COMMONPAGESIZE) in a linker script will
return 1, unlike in ld.bfd. However given that -n and -N disable paging
these probably shouldn't be used in a linker script where -n or -N is in
use.

Differential Revision: https://reviews.llvm.org/D61688

llvm-svn: 360593
2019-05-13 16:01:26 +00:00
Reid Kleckner c10f80eb7b [COFF] Update LLD yaml test cases to include .bss size
These yaml test cases appear to have been affected by PR41836

Right now what happens is that these empty .bss sections are merged into
.data, then the .data output section ends up having a zero virtual size,
and it is discarded from the output after addresses are assigned.
However, we've already assigned OutputSections to Chunks, so we don't
correctly report the zero-sized chunks that were in there as having been
discarded. Soon, we will report them as discarded, so these test cases
need to be updated to have a non-zero size so they aren't discarded.

llvm-svn: 360476
2019-05-10 22:12:51 +00:00
Fangrui Song 6150407951 [llvm-objdump] Print st_other
Add support for ".hidden" ".internal" ".protected" and " 0x%02x" for
other st_other bits used by some architectures.

Reviewed By: sfertile

Differential Revision: https://reviews.llvm.org/D61718

llvm-svn: 360439
2019-05-10 16:24:57 +00:00
Fangrui Song 6cdd68e386 [PPC64] Define getThunkSectionSpacing() based on the range of R_PPC64_REL24
Suggested by Sean Fertile and Peter Smith.

Thunk section spacing decrease the total number of thunks. I measured a
decrease of 1% or less in some large programs, with no perceivable
slowdown in link time. Override getThunkSectionSpacing() to enable it.
0x2000000 is the farthest point R_PPC64_REL24 can reach. I tried several
numbers and found 0x2000000 works the best. Numbers near 0x2000000 work
as well but let's just use the simpler number.

As demonstrated by the updated tests, this essentially changes placement
of most thunks to the end of the output section. We leverage this
property to fix PR40740 reported by Alfredo Dal'Ava Júnior:

The output section .init consists of input sections from several object
files (crti.o crtbegin.o crtend.o crtn.o). Sections other than the last
one do not have a terminator. With this patch, we create the thunk after
the last .init input section and thus fix the issue. This is not
foolproof but works quite well for such sections (with no terminator) in
practice.

Reviewed By: ruiu, sfertile

Differential Revision: https://reviews.llvm.org/D61720

llvm-svn: 360405
2019-05-10 05:51:00 +00:00
Sam Clegg ea38ac5ba3 [WebAssembly] Don't assume that strongly defined symbols are DSO-local
The current PIC model for WebAssembly is more like ELF in that it
allows symbol interposition.

This means that more functions end up being addressed via the GOT
and fewer directly added to the wasm table.

One effect is a reduction in the number of wasm table entries similar
to the previous attempt in https://reviews.llvm.org/D61539 which was
reverted.

Differential Revision: https://reviews.llvm.org/D61772

llvm-svn: 360402
2019-05-10 01:52:08 +00:00
Reid Kleckner 4c64256b51 [COFF] Simplify Chunk::writeTo and remove OutputSectionOff, NFC
Summary:
Prior to this change, every implementation of writeTo would add
OutputSectionOff to the output section buffer start before writing data.
Instead, do this math in the caller, so that it can be written once
instead of many times.

The output section offset is always equivalent to the difference between
the chunk RVA and the output section RVA, so we can replace the one
remaining usage of OutputSectionOff with that subtraction.

This doesn't change the size of SectionChunk because of alignment
requirements, but I will rearrange the fields in a follow-up change to
accomplish that.

Reviewers: ruiu, aganea

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D61696

llvm-svn: 360376
2019-05-09 21:21:22 +00:00
Sam Clegg 08fa01a9b7 Revert "[WebAssembly] Don't generate unused table entries."
This reverts commit b33fdb7768.

This change apparently broke am emscripten test.

llvm-svn: 360367
2019-05-09 19:34:32 +00:00
Ben Dunbobbin 3edca1ac1a [LLD][NFC] Refactor: BuildID hash size now computed in one place.
Differential Revision: https://reviews.llvm.org/D61078

llvm-svn: 360316
2019-05-09 08:08:09 +00:00
Fangrui Song bd086817f6 [ELF] Initialize Target before it may be dereferenced by findAux when reporting "duplicate symbol" error
for (InputFile *F : Files)
      Symtab->addFile<ELFT>(F); // if there is a duplicate symbol error

    ...

    Target = getTarget();

When parsing .debug_info in the object file (for better diagnostics),
DWARF.cpp findAux may dereference the null pointer Target

    auto *DR = dyn_cast<Defined>(&File->getRelocTargetSym(Rel));
    if (!DR) {
      // Broken debug info may point to a non-defined symbol,
      // some asan object files may also contain R_X86_64_NONE
      RelType Type = Rel.getType(Config->IsMips64EL);
      if (Type != Target->NoneRel) /// Target is null

Move the assignment of Target to an earlier place to fix this.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D61712

llvm-svn: 360305
2019-05-09 01:45:53 +00:00
Bob Haarman f3fb7fac32 [lld-link] initialize targets and asmparsers before invoking lib
Summary:
When using lld-link to build static libraries containing object files
with module assembly, the program would crash with "Assertion `T &&
T->hasMCAsmParser()' failed". This change causes the code in lld-link
that initialized Targets, TargetInfos, and AsmParsers (which already
existed) to be run before entering the lib building path (which needs
it). This avoids the error (and is what llvm-lib and llvm-ar do, too).

Fixes PR41803.

Reviewers: ruiu, rnk, hans

Reviewed By: ruiu

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D61699

llvm-svn: 360295
2019-05-08 22:11:02 +00:00
Sam Clegg a1282a39ba [WebAssembly] Handle command line options consistently with the ELF backend.
Differential Revision: https://reviews.llvm.org/D61645

llvm-svn: 360266
2019-05-08 16:20:05 +00:00
Reid Kleckner 34e9c41164 [COFF] Store Chunk RVAs and section offsets as uint32_t
Saves 8 bytes on SectionChunk, one of the most commonly allocated data
structures.

llvm-svn: 360188
2019-05-07 20:30:41 +00:00
Simon Atanasyan 3bdb81c26d [mips] Fix ld instruction in PLT entries on MIPS64
Use `ld` and `daddiu` instructions in MIPS64 PLT records. That fixes a
segmentation fault.

Patch by Qiao Pengcheng.

Differential Revision: https://reviews.llvm.org/D61586

llvm-svn: 360187
2019-05-07 20:26:23 +00:00
Simon Atanasyan 494b763cfc [mips] Rename test case. NFC
This test case checks MIPS PLT records for N64 ABI. For the N32 ABI case
there is a separate test case `mips-plt-n32.s`.

llvm-svn: 360186
2019-05-07 20:26:12 +00:00
Sam Clegg b33fdb7768 [WebAssembly] Don't generate unused table entries.
When generating PIC output only relocations of type
R_WASM_TABLE_INDEX_REL_SLEB should generate table entries.

R_WASM_TABLE_INDEX_I32 get resolved at runtime via the auto-generated
__wasm_apply_relocs functions.

R_WASM_TABLE_INDEX_SLEB are not allowed in PIC code.

Differential Revision: https://reviews.llvm.org/D61539

llvm-svn: 360165
2019-05-07 15:46:30 +00:00
Nico Weber 4b81e9f8d1 lld-link: Allow /? as option prefix, like -? is allowed
link.exe seems to allow `/?foo` and `-?foo` in addition to `/foo` and `-foo`.

Since lld-link already supports the `-?foo` spelling, support `/?foo` as well.

Differential Revision: https://reviews.llvm.org/D61375

llvm-svn: 360150
2019-05-07 14:15:35 +00:00
Nico Weber 54743d5767 Add typo correction for command-line flags to ELF and COFF lld drivers
For lld-link, unknown '/'-style flags are treated as filenames on POSIX
systems, so only '-'-style flags get typo correction for now. This
matches clang-cl.

PR37006.

Differential Revision: https://reviews.llvm.org/D61443

llvm-svn: 360145
2019-05-07 13:48:30 +00:00
George Rimar 72f7a98876 [LLD][ELF] - Remove symbol-name-offset.elf binary from test cases.
It was possible to convert the test case to YAML test.
After that, we have only one binary test left in LLD/ELF.

llvm-svn: 360139
2019-05-07 12:59:44 +00:00
Fangrui Song f3994e4dfa [ELF] Reorder BitcodeFiles.empty() to call thinLTOCreateEmptyIndexFiles() in only one place
It makes the --plugin-opt=obj-path= and --plugin-opt=thinlto-index-only=
behavior more consistent - the files will be created in the
BitcodeFiles.empty() case, but I assume whether it behaves this way is
not required by anyone.

LTOObj->run() cannot run with empty BitcodeFiles. There would be an error:

    ld.lld: error: No available targets are compatible with triple ""

Differential Revision: https://reviews.llvm.org/D61635

llvm-svn: 360129
2019-05-07 10:40:26 +00:00
Fangrui Song 912251e82f [PPC64] toc-indirect to toc-relative relaxation
This is based on D54720 by Sean Fertile.

When accessing a global symbol which is not defined in the translation unit,
compilers will generate instructions that load the address from the toc entry.

If the symbol is defined, non-preemptable, and addressable with a 32-bit
signed offset from the toc pointer, the address can be computed
directly. e.g.

    addis 3, 2, .LC0@toc@ha  # R_PPC64_TOC16_HA
    ld    3, .LC0@toc@l(3)   # R_PPC64_TOC16_LO_DS, load the address from a .toc entry
    ld/lwa 3, 0(3)           # load the value from the address

    .section .toc,"aw",@progbits
    .LC0: .tc var[TC],var

can be relaxed to

    addis 3,2,var@toc@ha     # this may be relaxed to a nop,
    addi  3,3,var@toc@l      # then this becomes addi 3,2,var@toc
    ld/lwa 3, 0(3)           # load the value from the address

We can delete the test ppc64-got-indirect.s as its purpose is covered by
newly added ppc64-toc-relax.s and ppc64-toc-relax-constants.s

Reviewed By: ruiu, sfertile

Differential Revision: https://reviews.llvm.org/D60958

llvm-svn: 360112
2019-05-07 04:26:05 +00:00
Sam Clegg 5f8c2edef3 [WebAssembly] Add more test coverage for reloctions against section symbols
The only known user of this relocation type and symbol type is
the debug info sections, but we were not testing the `--relocatable`
output path.

This change adds a minimal test case to cover relocations against
section symbols includes `--relocatable` output.

Differential Revision: https://reviews.llvm.org/D61623

llvm-svn: 360110
2019-05-07 03:53:16 +00:00
Fangrui Song 12fb52007b [AMDGPU][test] Define local symbols used in amdgpu-relocs.s
Differential Revision: https://reviews.llvm.org/D61594

llvm-svn: 360046
2019-05-06 14:17:59 +00:00
Alexander Kornienko 8b92ec521d [lld] A better version of the fix in r359942.
Thanks to George Rimar for the suggestion.

llvm-svn: 360040
2019-05-06 12:11:30 +00:00
Alexander Kornienko 3f796f974d [lld] Specify output file explicitly
The test shouldn't try to create `a.out` in the current directory, which can be
read-only (and it is in our test setup).

llvm-svn: 359942
2019-05-03 23:11:32 +00:00
Reid Kleckner 0a1b1d6e62 Shrink SectionChunk by combining Relocs and SectionName sizes
SectionChunk is one of the most frequently allocated data structures in
LLD, since there are about four per function when optimizations and
debug info are enabled (.text, .pdata, .xdata, .debug$S).

A PE COFF file cannot be larger than 2GB, so there is an inherent limit
on the length of the section name and the number of relocations.
Decompose the ArrayRef and StringRef into pointer and size, and put them
back together in the accessors for section name and relocation list.

I plan to gather complete performance numbers later by padding
SectionChunk with dead data and measuring performance after all the size
optimizations are done.

llvm-svn: 359923
2019-05-03 20:17:14 +00:00
Fangrui Song d45df09435 [ELF] Place SHT_NOTE sections with the same alignment into one PT_NOTE
Summary:
While the generic ABI requires notes to be 8-byte aligned in ELF64, many
vendor-specific notes (from Linux, NetBSD, Solaris, etc) use 4-byte
alignment.

In a PT_NOTE segment, if 4-byte aligned notes are followed by an 8-byte
aligned note, the possible 4-byte padding may make consumers fail to
parse the 8-byte aligned note. See PR41000 for a recent report about
.note.gnu.property (NT_GNU_PROPERTY_TYPE_0).
(Note, for NT_GNU_PROPERTY_TYPE_0, the consumers should probably migrate
to PT_GNU_PROPERTY, but the alignment issue affects other notes as well.)

To fix the issue, don't mix notes with different alignments in one
PT_NOTE. If compilers emit 4-byte aligned notes before 8-byte aligned
notes, we'll create at most 2 segments.

sh_size%sh_addralign=0 is actually implied by the rule for linking
unrecognized sections (in generic ABI), so we don't have to check that.
Notes that match in name, type and attribute flags are concatenated into
a single output section. The compilers have to ensure
sh_size%sh_addralign=0 to make concatenated notes parsable.

An alternative approach is to create a PT_NOTE for each SHT_NOTE, but
we'll have to incur the sizeof(Elf64_Phdr)=56 overhead every time a new
note section is introduced.

Reviewers: ruiu, jakehehrlich, phosek, jhenderson, pcc, espindola

Subscribers: emaste, arichardson, krytarowski, fedor.sergeev, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D61296

llvm-svn: 359853
2019-05-03 00:35:49 +00:00