Commit Graph

364211 Commits

Author SHA1 Message Date
Simon Pilgrim 42b993d97d [X86] ia32intrin.h - pull out common attributes used in cast helpers into define. NFCI. 2020-08-22 15:25:15 +01:00
Jeremy Morse 2d9be9e318 Fix some builds after 20bb9fe565
-Wsuggest-override indicates this VarLocBasedLDV method needs the
override keyword.
2020-08-22 15:20:42 +01:00
LLVM GN Syncbot eeb4636772 [gn build] Port 20bb9fe565 2020-08-22 13:52:08 +00:00
Jeremy Morse 20bb9fe565 [LiveDebugValues] Install an implementation-picking LiveDebugValues pass
This patch renames the current LiveDebugValues class to "VarLocBasedLDV"
and removes the pass-registration code from it. It creates a separate
LiveDebugValues class that deals with pass registration and management,
that calls through to VarLocBasedLDV::ExtendRanges when
runOnMachineFunction is called. This is done through the "LDVImpl"
abstract class, so that a future patch can install the new
instruction-referencing LiveDebugValues implementation and have it
picked at runtime.

No functional change is intended, just shuffling responsibilities.

Differential Revision: https://reviews.llvm.org/D83046
2020-08-22 14:50:22 +01:00
Simon Pilgrim e7d9182a66 Enable constexpr on BITREVERSE builtin intrinsics (PR47249)
This enables us to use the __builtin_bitreverse 8/16/32/64 intrinsics inside constexpr code.

Differential Revision: https://reviews.llvm.org/D86339
2020-08-22 14:43:22 +01:00
Simon Pilgrim 2ceac91ec0 Enable constexpr on ROTATELEFT/ROTATERIGHT builtin intrinsics (PR47249)
This enables us to use the __builtin_rotateleft / __builtin_rotateright 8/16/32/64 intrinsics inside constexpr code.

Differential Revision: https://reviews.llvm.org/D86342
2020-08-22 14:43:21 +01:00
Sanjay Patel ec06b38130 [InstCombine] canonicalize 'not' ops before logical shifts
This reverses the existing transform that would uniformly canonicalize any 'xor' after any shift. In the case of logical shifts, that turns a 'not' into an arbitrary 'xor' with constant, and that's probably not as good for analysis, SCEV, or codegen.

The SCEV motivating case is discussed in:
http://bugs.llvm.org/PR47136

There's an analysis motivating case at:
http://bugs.llvm.org/PR38781

I did draft a patch that would do the same for 'ashr' but that's questionable because it's just swapping the position of a 'not' and uncovers at least 2 missing folds that we would probably need to deal with as preliminary steps.

Alive proofs:
https://rise4fun.com/Alive/BBV

  Name: shift right of 'not'
  Pre: C2 == (-1 u>> C1)
  %a = lshr i8 %x, C1
  %r = xor i8 %a, C2
  =>
  %n = xor i8 %x, -1
  %r = lshr i8 %n, C1

  Name: shift left of 'not'
  Pre: C2 == (-1 << C1)
  %a = shl i8 %x, C1
  %r = xor i8 %a, C2
  =>
  %n = xor i8 %x, -1
  %r = shl i8 %n, C1

  Name: ashr of 'not'
  %a = ashr i8 %x, C1
  %r = xor i8 %a, -1
  =>
  %n = xor i8 %x, -1
  %r = ashr i8 %n, C1

Differential Revision: https://reviews.llvm.org/D86243
2020-08-22 09:38:13 -04:00
Sanjay Patel 2fc7c85201 [DAGCombiner] clean up merge of truncated stores; NFC
This code handles the special-case of i8 stores,
but it could be generalized to deal with other types.
2020-08-22 09:23:32 -04:00
Simon Pilgrim 436a35a773 [docs] Replace "constexpr expressions" with "constant expressions".
Based off comment from @rsmith on D86339
2020-08-22 14:14:36 +01:00
Nathan James df5335a36d
[clang-tidy] readability-simplify-boolean-expr detects negated literals
Adds support for detecting cases like `if (!true) ...`.
Addresses [[ https://bugs.llvm.org/show_bug.cgi?id=47166 | readability-simplify-boolean-expr not detected for negated boolean literals. ]]

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D86176
2020-08-22 13:57:36 +01:00
LLVM GN Syncbot cfc76d2bce [gn build] Port fba06e3c85 2020-08-22 12:40:06 +00:00
Jeremy Morse fba06e3c85 [LiveDebugValues][NFC] Move LiveDebugValues source for refactor
This is a pure file move of LiveDebugValues.cpp ahead of the pass being
refactored, with an experimental new implementation to follow.

The motivation for these changes can be found here:

  http://lists.llvm.org/pipermail/llvm-dev/2020-June/142368.html

And the other related changes can be found in the phabricator stack for
this revision:

Differential Revision: https://reviews.llvm.org/D83304
2020-08-22 12:58:30 +01:00
Dimitry Andric 1ce07cd614 Instantiate Error in Target::GetEntryPointAddress() only when necessary
When `Target::GetEntryPointAddress()` calls `exe_module->GetObjectFile()->GetEntryPointAddress()`, and the returned
`entry_addr` is valid, it can immediately be returned.

However, just before that, an `llvm::Error` value has been setup, but in this case it is not consumed before returning, like is done further below in the function.

In https://bugs.freebsd.org/248745 we got a bug report for this, where a very simple test case aborts and dumps core:

```
* thread #1, name = 'testcase', stop reason = breakpoint 1.1
    frame #0: 0x00000000002018d4 testcase`main(argc=1, argv=0x00007fffffffea18) at testcase.c:3:5
   1	int main(int argc, char *argv[])
   2	{
-> 3	    return 0;
   4	}
(lldb) p argc
Program aborted due to an unhandled Error:
Error value was Success. (Note: Success values must still be checked prior to being destroyed).

Thread 1 received signal SIGABRT, Aborted.
thr_kill () at thr_kill.S:3
3	thr_kill.S: No such file or directory.
(gdb) bt
#0  thr_kill () at thr_kill.S:3
#1  0x00000008049a0004 in __raise (s=6) at /usr/src/lib/libc/gen/raise.c:52
#2  0x0000000804916229 in abort () at /usr/src/lib/libc/stdlib/abort.c:67
#3  0x000000000451b5f5 in fatalUncheckedError () at /usr/src/contrib/llvm-project/llvm/lib/Support/Error.cpp:112
#4  0x00000000019cf008 in GetEntryPointAddress () at /usr/src/contrib/llvm-project/llvm/include/llvm/Support/Error.h:267
#5  0x0000000001bccbd8 in ConstructorSetup () at /usr/src/contrib/llvm-project/lldb/source/Target/ThreadPlanCallFunction.cpp:67
#6  0x0000000001bcd2c0 in ThreadPlanCallFunction () at /usr/src/contrib/llvm-project/lldb/source/Target/ThreadPlanCallFunction.cpp:114
#7  0x00000000020076d4 in InferiorCallMmap () at /usr/src/contrib/llvm-project/lldb/source/Plugins/Process/Utility/InferiorCallPOSIX.cpp:97
#8  0x0000000001f4be33 in DoAllocateMemory () at /usr/src/contrib/llvm-project/lldb/source/Plugins/Process/FreeBSD/ProcessFreeBSD.cpp:604
#9  0x0000000001fe51b9 in AllocatePage () at /usr/src/contrib/llvm-project/lldb/source/Target/Memory.cpp:347
#10 0x0000000001fe5385 in AllocateMemory () at /usr/src/contrib/llvm-project/lldb/source/Target/Memory.cpp:383
#11 0x0000000001974da2 in AllocateMemory () at /usr/src/contrib/llvm-project/lldb/source/Target/Process.cpp:2301
#12 CanJIT () at /usr/src/contrib/llvm-project/lldb/source/Target/Process.cpp:2331
#13 0x0000000001a1bf3d in Evaluate () at /usr/src/contrib/llvm-project/lldb/source/Expression/UserExpression.cpp:190
#14 0x00000000019ce7a2 in EvaluateExpression () at /usr/src/contrib/llvm-project/lldb/source/Target/Target.cpp:2372
#15 0x0000000001ad784c in EvaluateExpression () at /usr/src/contrib/llvm-project/lldb/source/Commands/CommandObjectExpression.cpp:414
#16 0x0000000001ad86ae in DoExecute () at /usr/src/contrib/llvm-project/lldb/source/Commands/CommandObjectExpression.cpp:646
#17 0x0000000001a5e3ed in Execute () at /usr/src/contrib/llvm-project/lldb/source/Interpreter/CommandObject.cpp:1003
#18 0x0000000001a6c4a3 in HandleCommand () at /usr/src/contrib/llvm-project/lldb/source/Interpreter/CommandInterpreter.cpp:1762
#19 0x0000000001a6f98c in IOHandlerInputComplete () at /usr/src/contrib/llvm-project/lldb/source/Interpreter/CommandInterpreter.cpp:2760
#20 0x0000000001a90b08 in Run () at /usr/src/contrib/llvm-project/lldb/source/Core/IOHandler.cpp:548
#21 0x00000000019a6c6a in ExecuteIOHandlers () at /usr/src/contrib/llvm-project/lldb/source/Core/Debugger.cpp:903
#22 0x0000000001a70337 in RunCommandInterpreter () at /usr/src/contrib/llvm-project/lldb/source/Interpreter/CommandInterpreter.cpp:2946
#23 0x0000000001d9d812 in RunCommandInterpreter () at /usr/src/contrib/llvm-project/lldb/source/API/SBDebugger.cpp:1169
#24 0x0000000001918be8 in MainLoop () at /usr/src/contrib/llvm-project/lldb/tools/driver/Driver.cpp:675
#25 0x000000000191a114 in main () at /usr/src/contrib/llvm-project/lldb/tools/driver/Driver.cpp:890```

Fix the incorrect error catch by only instantiating an `Error` object if it is necessary.

Reviewed By: JDevlieghere

Differential Revision: https://reviews.llvm.org/D86355
2020-08-22 12:47:13 +02:00
Florian Hahn 5e7e2162d4 [DSE,MemorySSA] Use BatchAA for AA queries.
We can use BatchAA to avoid some repeated AA queries. We only remove
stores, so I think we will get away with using a single BatchAA instance
for the complete run.

The changes in AliasAnalysis.h mirror the changes in D85583.

The change improves compile-time by roughly 1%.
http://llvm-compile-time-tracker.com/compare.php?from=67ad786353dfcc7633c65de11601d7823746378e&to=10529e5b43809808e8c198f88fffd8f756554e45&stat=instructions

This is part of the patches to bring down compile-time to the level
referenced in
http://lists.llvm.org/pipermail/llvm-dev/2020-August/144417.html

Reviewed By: asbirlea

Differential Revision: https://reviews.llvm.org/D86275
2020-08-22 08:36:35 +01:00
George Mitenkov b65ba70479 [MLIR][SPIRVToLLVM] Updated the documentation for the conversion
This patch updates the SPIR-V to LLVM conversion manual.
Particularly, the following sections are added:
- `spv.EntryPoint`/`spv.ExecutionMode` handling
- Mapping for `spv.AccessChain`
- Change in allowed storage classes for `spv.globalVariable`
- Change of the runner section name

Reviewed By: mravishankar

Differential Revision: https://reviews.llvm.org/D86288
2020-08-22 10:04:03 +03:00
Fangrui Song 7646a67104 [DebugInfo][test] Move distringtype.ll to X86/ subdir to fix failures when X86 target is not built 2020-08-21 23:14:36 -07:00
Uday Bondhugula b8cc449b84 [MLIR][NFC] Update MLIR vim syntax file - std ops + types
Update vim syntax file to include more std ops, and for int types.

Differential Revision: https://reviews.llvm.org/D86370
2020-08-22 11:20:57 +05:30
Sourabh Singh Tomar 12edd4b364 Fix arm bot failure after f91d18eaa9
llc doesn't seem to automatically pick default `--triple`.
using `%llc_dwarf` should fix this.

Builder:
http://lab.llvm.org:8011/builders/clang-cmake-armv7-quick/builds/20310

Error log:
bin/llc: error: : error: unable to get target for 'x86_64-unknown-linux-gnu', see --version and --triple.
2020-08-22 11:06:10 +05:30
Sourabh Singh Tomar f91d18eaa9 [DebugInfo][flang]Added support for representing Fortran assumed length strings
This patch adds support for representing Fortran `character(n)`.

Primarily patch is based out of D54114 with appropriate modifications.

Test case IR is generated using our downstream classic-flang. We're in process
of upstreaming flang PR's but classic-flang has dependencies on llvm, so
this has to get in first.

Patch includes functional test case for both IR and corresponding
dwarf, furthermore it has been manually tested as well using GDB.

Source snippet:
```
 program assumedLength
   call sub('Hello')
   call sub('Goodbye')
   contains
   subroutine sub(string)
           implicit none
           character(len=*), intent(in) :: string
           print *, string
   end subroutine sub
 end program assumedLength
```

GDB:
```
(gdb) ptype string
type = character (5)
(gdb) p string
$1 = 'Hello'
```

Reviewed By: aprantl, schweitz

Differential Revision: https://reviews.llvm.org/D86305
2020-08-22 10:13:40 +05:30
Jonas Devlieghere 86fc193309 [lldb] Don't pass --rerun-all-issues on Windows.
The functionality has been removed for a while and now the dotest
argument has been removed asll.
2020-08-21 19:58:24 -07:00
Azharuddin Mohammed 6a64079699 Fix llvm/test/tools/lto/hide-linkonce-odr.ll
Remove unnecessary dependency on libSystem.
2020-08-21 18:32:35 -07:00
Josh Stone b26b32b5d3 lld: link libatomic if needed for Timer
D80298 made Timer::total atomic, but this requires linking libatomic
on some targets.

Reviewed By: aaronpuchert

Differential Revision: https://reviews.llvm.org/D85691
2020-08-21 17:47:55 -07:00
Alina Sbirlea f55ad3973d [DomTree] Extend update API to allow a post CFG view.
Extend the `applyUpdates` in DominatorTree to allow a post CFG view,
different from the current CFG.
This patch implements the functionality of updating an already up to
date DT, to the desired PostCFGView.
Combining a set of updates towards an up to date DT and a PostCFGView is
not yet supported.

Differential Revision: https://reviews.llvm.org/D85472
2020-08-21 17:23:08 -07:00
Fangrui Song 72ddaeddda [Attributor][test] Add REQUIRES: asserts after D86129 2020-08-21 16:20:41 -07:00
António Afonso 02bf5632a9 Fix swig scripts install target name
LLVM install component targets needs to be in the form of: install-{target}[-stripped]

I tested with:
```
cmake ... -DLLVM_ENABLE_PROJECTS="clang;lldb" -DLLVM_DISTRIBUTION_COMPONENTS="lldb;liblldb;lldb-python-scripts;" ...
DESTDIR=... ninja install-distribution
```

@JDevlieghere `finish_swig_python_scripts` is a really weird name for a distribution component, any reason that it has to be this way?

Differential Revision: https://reviews.llvm.org/D86235
2020-08-21 14:41:52 -07:00
Paul C. Anagnostopoulos 196e6f9f18 Replace TableGen range piece punctuator with '...'
The TableGen range piece punctuator is currently '-' (e.g., {0-9}),
which interacts oddly with the fact that an integer literal's sign
is part of the literal. This patch replaces the '-' with the new
punctuator '...'. The '-' punctuator is deprecated.

Differential Revision: https://reviews.llvm.org/D85585

Change-Id: I3d53d14e23f878b142d8f84590dd465a0fb6c09c
2020-08-21 23:33:57 +02:00
Roman Lebedev 503deec218
Temporairly revert "[SimplifyCFG][LoopRotate] SimplifyCFG: disable common instruction hoisting by default, enable late in pipeline"
As disscussed in post-commit review starting with
	https://reviews.llvm.org/D84108#2227365
while this appears to be mostly a win overall, especially code-size-wise,
this appears to shake //certain// code pattens in a way that is extremely
unfavorable for performance (+30% runtime regression)
on certain CPU's (i personally can't reproduce).

So until the behaviour is better understood, and a path forward is mapped,
let's back this out for now.

This reverts commit 1d51dc38d8.
2020-08-22 00:33:22 +03:00
Christopher Tetreault 5eff21c8ff [NFC][documentation] clarify comment in test
test referenced a relative path to a file, but the path was not correct
relative to the project the test is in

Differential Revision: https://reviews.llvm.org/D86368
2020-08-21 14:30:47 -07:00
Jonas Devlieghere d3a49b03a5 [lldb] Remove --rerun-all-issues as its functionality no longer exists
The logic behind --rerun-all-issues was removed when we switched to LIT
as the test driver. This patch just removes the dotest option and
corresponding entry in configuration.py.
2020-08-21 14:28:08 -07:00
Nicolai Hähnle 17cd34409a Fix two bugs in TGParser::ParseValue
TGParser::ParseValue contains two recursive calls, one to parse the RHS of a list paste operator and one to parse the RHS of a paste operator in a class/def name. Both of these calls neglect to check the return value to see if it is null (because of some error). This causes a crash in the next line of code, which uses the return value. The code now checks for null returns.

Differential Revision: https://reviews.llvm.org/D85852
2020-08-21 23:19:36 +02:00
Paul C. Anagnostopoulos e0c01e6cb0 New TableGen Programmer's Reference document
This new TableGen Programmer's Reference document replaces the current Language Introduction and Language Reference documents. It brings all the TableGen reference information into one document.

As an experiment, I numbered the sections in the document. See what you think about that.

Reviewed By: lattner

Differential Revision: https://reviews.llvm.org/D85838

(changes by Nicolai Hähnle <nicolai.haehnle@amd.com>:
- fixed build error due to toctree in docs/LangRef/index.rst
- fixed reference to ProgRef)

Change-Id: Ifbdfa39768b8a460aae2873103d31c7b347aff00
2020-08-21 23:18:32 +02:00
Arthur Eubanks b79889c2b1 [opt][NewPM] Add basic-aa in legacy PM compatibility mode
The legacy PM alias analysis pipeline by default includes basic-aa.
When running `opt -foo-pass` under the NPM and -disable-basic-aa is not
specified, use basic-aa.

This decreases the number of check-llvm failures under NPM from 913 to 752.

Reviewed By: ychen, asbirlea

Differential Revision: https://reviews.llvm.org/D86167
2020-08-21 14:05:07 -07:00
Nicolai Hähnle b37db11d95 MachineSSAUpdater: Allow initialization with just a register class
The register class is required for inserting PHIs, but the "current
virtual register" isn't actually used for anything, so let's remove it
while we're at it.

Differential Revision: https://reviews.llvm.org/D85602

Change-Id: I1e647f31570ef21a7ea8e20db3454178e98a6a8b
2020-08-21 23:04:35 +02:00
kuterd 65fcc0ee31 [Attributor] Function seed allow list
-  Adds a command line option to seed only selected functions.
  - Makes seed allow listing exclusive to assertions enabled builds.

Reviewed By: sstefan1

Differential Revision: https://reviews.llvm.org/D86129
2020-08-21 23:55:26 +03:00
Alina Sbirlea 7ea0ee3058 [DomTree] Avoid creating an empty GD to reduce compile time. 2020-08-21 13:45:00 -07:00
Jonas Devlieghere 52e758f352 [lldb] Fix build error in TestSimulatorPlatform.py
Before e5d08fcbac the Makefile would always compute the min-version,
even if it wasn't set in the triple. This nuance got lost when passing
the ARCH_CFLAGS directly from TestSimulatorPlatform.
2020-08-21 13:35:26 -07:00
Shinji Okumura e21a22a7a8 [Attributor] fix AANoUndef initialization
Currently, `AANoUndefImpl::initialize` mistakenly always indicates optimistic fixpoint for function returned position.
 This is because an associated value is `Function` in the case, and `isGuaranteedNotToBeUndefOrPoison` returns true for Function.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D86361
2020-08-22 05:06:14 +09:00
Amy Huang 5e3fd471ac [Cloning] Fix to cloning DISubprograms.
When trying to enable -debug-info-kind=constructor there was an assert
that occurs during debug info cloning ("mismatched subprogram between
llvm.dbg.value variable and !dbg attachment").
It appears that during llvm::CloneFunctionInto, a DISubprogram could be
duplicated when MapMetadata is called, and then added to the MD map again
when DIFinder gets a list of subprograms. This results in two different
versions of the DISubprogram.

This patch switches the order so that the DIFinder subprograms are
added before MapMetadata is called.

Fixes https://bugs.llvm.org/show_bug.cgi?id=46784

Differential Revision: https://reviews.llvm.org/D86185
2020-08-21 11:54:56 -07:00
Craig Topper c0ec37ee65 [docs] Move the label for __builtin_shufflevector below __builtin_dump_struct so the see also link in 'vector operations' will go to the right place and have the right name. 2020-08-21 11:51:15 -07:00
Stanislav Mekhanoshin 9a9a092e61 [AMDGPU] Avoid sorting stalls in regbank-reassign
This is the slowest operation in the already slow pass.
Instead of sorting just put a stall list into an ordered
map.

Differential Revision: https://reviews.llvm.org/D86253
2020-08-21 11:49:41 -07:00
Vaibhav Garg aca191cce1 Re-land 7a527f1777 with fixes.
The original commit was reverted in 58c305f466
due to broken bots. This commit corrects the triple and command line paths.
2020-08-21 14:40:09 -04:00
Serguei Katkov 9e362bb0eb [InstCombine] Remove unused entries in gc-live bundle of statepoint
If some of gc live value are not used in gc.relocate we can remove them
from gc-live bundle of statepoint instruction.

Also the CL removes duplicated Values in gc-live bundle.

Reviewers: reames, dantrushin
Reviewed By: dantrushin
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D85959
2020-08-22 01:36:22 +07:00
Wolfgang Pieb cf6adecd6a [llvm-mca][NFC] Refactor views to separate data collection from printing.
Reviewed By: andreadb, lebedev.ri

    Differential Revision: https://reviews.llvm.org/D86177
2020-08-21 11:27:36 -07:00
Fangrui Song 06cad825cd PrintStackTrace: don't symbolize if LLVM_DISABLE_SYMBOLIZATION is set
See http://lists.llvm.org/pipermail/llvm-dev/2017-June/113975.html for a related previous discussion.
Many tools install signal handlers to print stack traces and optionally
symbolize the addresses with an external program 'llvm-symbolizer' (when
searching for 'llvm-symbolizer', the directory containg the executable
is preferred over PATH).

'llvm-symbolizer' can be slow if the executable is large and/or if
llvm-symbolizer' itself is under-optimized. For example, my 'llvm-lto2' from a
-DCMAKE_BUILD_TYPE=Debug build is 443MiB. The 'llvm-symbolizer' from the same
build takes ~2s to symbolize it. (An optimized 'llvm-symbolizer' takes 0.34s).
A crashed clang may take more than 5s to symbolize a stack trace.

If a test file has several `not --crash` RUN lines. It can be very slow in a Debug build.
This patch makes `not --crash` set an environment variable to suppress symbolization.
This is similar to D33804 which uses a command line option.
I pick 'symbolization' instead of 'symbolication' because the former is
used much more commonly and its stem matches 'llvm-symbolizer'.

Also set LLVM_DISABLE_CRASH_REPORT=1, which is currently only applicable on
`__APPLE__`.

Reviewed By: dblaikie, aganea

Differential Revision: https://reviews.llvm.org/D86170
2020-08-21 11:27:13 -07:00
Stefan Pintilie 0cadd162b7 Forgot to update the test case for ppc64-tls-missing-gdld.s for 02e02f5398 2020-08-21 13:22:01 -05:00
Jonas Devlieghere 57e0ef131b [lldb] Make it a fatal error when %lldb cannot be substituted
Refuse to run the shell tests when %lldb cannot be substituted. This
prevents the test from silently running again the `lldb` in your PATH.

I noticed because when this happens, %lldb-init gets substituted with
lldb-init, which does not exists.
2020-08-21 11:18:21 -07:00
Julian Lettner cc62373915 [ASan][Darwin] Enable test on additional platforms 2020-08-21 11:13:09 -07:00
Qiu Chaofan a5b7b8cce0 [PowerPC] Support constrained scalar sitofp/uitofp
This patch adds support for constrained scalar int to fp operations on
PowerPC. Besides, this also fixes the FP exception bit of FCFID*
instructions.

Reviewed By: steven.zhang, uweigand

Differential Revision: https://reviews.llvm.org/D81669
2020-08-22 02:10:29 +08:00
Aden Grue 670063eb22 Preserve the error message when MemoryBuffer creation fails
Reviewed By: mehdi_amini

Differential Revision: https://reviews.llvm.org/D86326
2020-08-21 18:03:25 +00:00
Stefan Pintilie 02e02f5398 [LLD][PowerPC] Add check in LLD to produce an error for missing TLSGD/TLSLD
The function `__tls_get_addr` is used to get the address of an object that is Thread Local Storage.
It needs to have two relocations on it.
One relocation is for the function call itself and it is either R_PPC64_REL24 or R_PPC64_REL24_NOTOC.
The other is R_PPC64_TLSGD or R_PPC64_TLSLD for the symbol that is having its address computed.

In the early days of the transition from the ELFv1 ABI that is used for big endian PowerPC Linux distributions to the ELFv2 ABI that is used for little endian PowerPC Linux distributions, there was some ambiguity in the specification of the relocations for TLS. The GNU linker has implemented support for correct handling of calls to __tls_get_addr with a missing relocation. Unfortunately, we didn't notice that the IBM XL compiler did not handle TLS according to the updated ABI until we tried linking XL compiled libraries with LLD. As a result, there is a lot of code out there in various libraries compiled with XL that have this problem.

This patch adds a new error check in LLD that makes sure calls to `__tls_get_addr` are not missing the TLSGD/TLSLD relocation.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D85994
2020-08-21 12:56:12 -05:00