Commit Graph

460 Commits

Author SHA1 Message Date
Bruno Cardoso Lopes f446282aad Revert "[DebugInfo] Generate DWARF debug information for labels. (Fix leak problems)"
This reverts commit cb8c5e417d55141f3f079a8a876e786f44308336 / r339676.

This causing a test to fail in http://green.lab.llvm.org/green/job/clang-stage1-configure-RA/48406/

    LLVM :: DebugInfo/Generic/debug-label.ll

llvm-svn: 339700
2018-08-14 17:54:41 +00:00
Hsiangkai Wang ccae278938 [DebugInfo] Generate DWARF debug information for labels. (Fix leak problems)
There are two forms for label debug information in DWARF format.

1. Labels in a non-inlined function:

DW_TAG_label
  DW_AT_name
  DW_AT_decl_file
  DW_AT_decl_line
  DW_AT_low_pc

2. Labels in an inlined function:

DW_TAG_label
  DW_AT_abstract_origin
  DW_AT_low_pc

We will collect label information from DBG_LABEL. Before every DBG_LABEL,
we will generate a temporary symbol to denote the location of the label.
The symbol could be used to get DW_AT_low_pc afterwards. So, we create a
mapping between 'inlined label' and DBG_LABEL MachineInstr in DebugHandlerBase.
The DBG_LABEL in the mapping is used to query the symbol before it.

The AbstractLabels in DwarfCompileUnit is used to process labels in inlined
functions.

We also keep a mapping between scope and labels in DwarfFile to help to
generate correct tree structure of DIEs.

It also generates label debug information under global isel.

Differential Revision: https://reviews.llvm.org/D45556

llvm-svn: 339676
2018-08-14 13:50:59 +00:00
Lei Liu 8e422b8403 [AArch64] DWARF: do not generate AT_location for thread local
AArch64 ELF ABI does not define a static relocation type for TLS offset within
a module, which makes it impossible for compiler to generate a valid
DW_AT_location content for thread local variables. Currently LLVM generates an
invalid R_AARCH64_ABS64 relocation at the DW_AT_location field for a TLS
variable. That causes trouble for linker because thread local variable does
not have an absolute address at link time. AArch64 GCC solves the problem by
not generating DW_AT_location for thread local variables. We should do the
same in LLVM.

Differential Revision: https://reviews.llvm.org/D43860

llvm-svn: 338655
2018-08-01 23:46:49 +00:00
Alexey Bataev d4dd7215f6 [DEBUGINFO] Disable emission of the dwarf sections, but allow directives.
Summary:
Added an option that allows to emit only '.loc' and '.file' kind debug
directives, but disables emission of the DWARF sections. Required for
NVPTX target to support profiling. It requires '.loc' and '.file'
directives, but does not require any DWARF sections for the profiler.

Reviewers: probinson, echristo, dblaikie

Subscribers: aprantl, JDevlieghere, llvm-commits

Differential Revision: https://reviews.llvm.org/D46021

llvm-svn: 338616
2018-08-01 19:38:20 +00:00
Vlad Tsyrklevich 48ed9acede Revert "[DebugInfo] Generate DWARF debug information for labels."
This reverts commits r338390 and r338398, they were causing LSan
failures on the ASan bot.

llvm-svn: 338408
2018-07-31 18:10:37 +00:00
Hsiangkai Wang cbc58ada99 [DebugInfo] Generate DWARF debug information for labels.
There are two forms for label debug information in DWARF format.

1. Labels in a non-inlined function:

DW_TAG_label
  DW_AT_name
  DW_AT_decl_file
  DW_AT_decl_line
  DW_AT_low_pc

2. Labels in an inlined function:

DW_TAG_label
  DW_AT_abstract_origin
  DW_AT_low_pc

We will collect label information from DBG_LABEL. Before every DBG_LABEL,
we will generate a temporary symbol to denote the location of the label.
The symbol could be used to get DW_AT_low_pc afterwards. So, we create a
mapping between 'inlined label' and DBG_LABEL MachineInstr in DebugHandlerBase.
The DBG_LABEL in the mapping is used to query the symbol before it.

The AbstractLabels in DwarfCompileUnit is used to process labels in inlined
functions.

We also keep a mapping between scope and labels in DwarfFile to help to
generate correct tree structure of DIEs.

It also generates label debug information under global isel.

Differential Revision: https://reviews.llvm.org/D45556

llvm-svn: 338390
2018-07-31 14:48:32 +00:00
Wolfgang Pieb 9ea65082ff [DWARF v5] Reposting r337981, which was reverted in r337997 due to a test failure in debuginfo_tests.
The test failure was caused by the compiler not emitting a __debug_ranges section with DWARF 4 and
earlier when no ranges are needed. The test checks for the existence regardless.

llvm-svn: 338081
2018-07-26 22:48:52 +00:00
Alexey Bataev 4dd7558fab [DEBUGINFO, NVPTX] Emit correct debug information for local variables.
Summary:
NVPTX target dos not use register-based frame information. Instead it
relies on the artificial local_depot that is used instead of the frame
and the data for variables must be emitted relatively to this
local_depot.

Reviewers: tra, jlebar, echristo

Subscribers: jholewinski, aprantl, JDevlieghere, llvm-commits

Differential Revision: https://reviews.llvm.org/D45963

llvm-svn: 338039
2018-07-26 16:29:52 +00:00
Alexey Bataev 7ae86fe71c [DEBUGINFO, NVPTX] Set `DW_AT_frame_base` to `DW_OP_call_frame_cfa`.
Summary:
For NVPTX target the value of `DW_AT_frame_base` attribute must be set
to `DW_OP_call_frame_cfa`.

Reviewers: tra, jlebar, echristo

Subscribers: jholewinski, JDevlieghere, llvm-commits

Differential Revision: https://reviews.llvm.org/D45785

llvm-svn: 338036
2018-07-26 16:10:05 +00:00
Alex Lorenz 7d808c19ff Revert r337981: it breaks the debuginfo-tests
This commit caused a regression in the debuginfo-tests:

FAIL: debuginfo-tests :: apple-accel.cpp (40748 of 46595)
llvm-svn: 337997
2018-07-26 03:21:40 +00:00
Wolfgang Pieb c42087df7c [DWARF v5] Don't emit multiple DW_AT_rnglists_base attributes. Some refactoring of
range lists emissions and added test cases.

Reviewer: dblaikie

Differential Revision: https://reviews.llvm.org/D49522

llvm-svn: 337981
2018-07-25 23:03:22 +00:00
Shiva Chen f5938bfbf9 Revert "[DebugInfo] Generate DWARF debug information for labels."
This reverts commit b454fa1b4079b6c0a5b1565982d16516385838d7.

llvm-svn: 337812
2018-07-24 06:17:45 +00:00
Shiva Chen d6b2cdf9d4 [DebugInfo] Generate DWARF debug information for labels.
There are two forms for label debug information in DWARF format.

1. Labels in a non-inlined function:

DW_TAG_label
  DW_AT_name
  DW_AT_decl_file
  DW_AT_decl_line
  DW_AT_low_pc

2. Labels in an inlined function:

DW_TAG_label
  DW_AT_abstract_origin
  DW_AT_low_pc

We will collect label information from DBG_LABEL. Before every DBG_LABEL,
we will generate a temporary symbol to denote the location of the label.
The symbol could be used to get DW_AT_low_pc afterwards. So, we create a
mapping between 'inlined label' and DBG_LABEL MachineInstr in DebugHandlerBase.
The DBG_LABEL in the mapping is used to query the symbol before it.

The AbstractLabels in DwarfCompileUnit is used to process labels in inlined
functions.

We also keep a mapping between scope and labels in DwarfFile to help to
generate correct tree structure of DIEs.

Differential Revision: https://reviews.llvm.org/D45556

Patch by Hsiangkai Wang.

llvm-svn: 337799
2018-07-24 02:22:55 +00:00
Wolfgang Pieb fcf3810cf7 [DWARF v5] Generate range list tables into the .debug_rnglists section. No support for split DWARF
and no use of DW_FORM_rnglistx with the DW_AT_ranges attribute.

Reviewer: aprantl

Differential Revision: https://reviews.llvm.org/D49214

llvm-svn: 336927
2018-07-12 18:18:21 +00:00
Paul Robinson 543c0e1d50 [DWARFv5] Put the DWO ID in its place.
In DWARF v5, the DWO ID is in the (split/skeleton) CU header, not an
attribute on the CU DIE.

This changes the size of those headers, so use the parsed size whenever
we have one, for simplicitly.

Differential Revision: https://reviews.llvm.org/D47158

llvm-svn: 333004
2018-05-22 17:27:31 +00:00
Pavel Labath 2a6afe5f87 [CodeGen/AccelTable]: Handle -dwarf-linkage-names=Abstract correctly
Summary:
If we are not emitting a linkage name in the .debug_info sections, we
should not add it into the index either. This makes sure our index is
consistent with the actual debug info.

I am also explicitly setting the --dwarf-linkage-names=All in the
name-collsions test as that one would now fail on targets where this
defaults to "Abstract" (in fact, it would have failed already if there
wasn't a bug in the DWARF verifier, which I fix as well).

Reviewers: probinson, aprantl, JDevlieghere

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D46748

llvm-svn: 332246
2018-05-14 14:13:20 +00:00
Adrian Prantl 3edc63a579 DwarfCompileUnit: Fix another assertion failure on malformed input
that is not rejected by the Verifier.

Thanks to Björn Pettersson for providing a reproducer!

llvm-svn: 331535
2018-05-04 16:10:43 +00:00
Adrian Prantl 4b542c6e64 Fix a bug that prevents global variables from having a DW_OP_deref.
For local variables the first DW_OP_deref is consumed by turning the
location kind into a memeory location, but that only makes sense for
values that are in a register to begin with, which cannot happen for
global variables that are attached to a symbol.

rdar://problem/39741860

This reapplies r330970 after fixing an uncovered bug in r331086 and
working around the situation caused by it.

llvm-svn: 331090
2018-04-27 22:05:31 +00:00
Adrian Prantl 855b91022d Revert "Fix a bug that prevents global variables from having a DW_OP_deref."
This reverts commit r3309704 while investigating bot breakage.

llvm-svn: 330993
2018-04-26 20:59:58 +00:00
Adrian Prantl e42805d07c Fix a bug that prevents global variables from having a DW_OP_deref.
For local variables the first DW_OP_deref is consumed by turning the
location kind into a memeory location, but that only makes sense for
values that are in a register to begin with, which cannot happen for
global variables that are attached to a symbol.

rdar://problem/39741860

llvm-svn: 330970
2018-04-26 18:17:04 +00:00
David Blaikie 6054e650ff Move TargetLoweringObjectFile from CodeGen to Target to fix layering
It's implemented in Target & include from other Target headers, so the
header should be in Target.

llvm-svn: 328392
2018-03-23 23:58:19 +00:00
Alexey Bataev bff360865b [DEBUGINFO] Add flag for DWARF2 to use sections as references.
Summary:
Some targets does not support labels inside debug sections, but support
references in form `section+offset`. Patch adds initial support
for this.

Reviewers: echristo, probinson, jlebar

Subscribers: llvm-commits, JDevlieghere

Differential Revision: https://reviews.llvm.org/D43943

llvm-svn: 328314
2018-03-23 13:35:54 +00:00
Alexey Bataev 858a7dd6d7 [DEBUGINFO] Add -no-dwarf-debug-ranges option.
Summary:
Added option -no-dwarf-debug-ranges option to disable emission of
.debug_ranges section.

Reviewers: probinson, echristo

Subscribers: aprantl, JDevlieghere, llvm-commits

Differential Revision: https://reviews.llvm.org/D44384

llvm-svn: 328030
2018-03-20 20:21:38 +00:00
Alexey Bataev 648ed2dedb [DEBUGINFO] Add flag -no-dwarf-pub-sections to disable pub sections.
Summary:
Added a flag -no-dwarf-pub-sections, which allows to disable
emission of DWARF public sections.

Reviewers: probinson, echristo

Subscribers: aprantl, JDevlieghere, llvm-commits

Differential Revision: https://reviews.llvm.org/D44385

llvm-svn: 327994
2018-03-20 16:04:40 +00:00
Alexey Bataev d7c6fdbcd5 Revert "[DEBUGINFO] Add flag for DWARF2 or less to use sections as references."
This reverts commit r326328 to remove checks for emission of certain
sections after discussion with Eric Christofer.

llvm-svn: 326436
2018-03-01 14:32:37 +00:00
Chih-Hung Hsieh 9f9e4681ac [TLS] use emulated TLS if the target supports only this mode
Emulated TLS is enabled by llc flag -emulated-tls,
which is passed by clang driver.
When llc is called explicitly or from other drivers like LTO,
missing -emulated-tls flag would generate wrong TLS code for targets
that supports only this mode.
Now use useEmulatedTLS() instead of Options.EmulatedTLS to decide whether
emulated TLS code should be generated.
Unit tests are modified to run with and without the -emulated-tls flag.

Differential Revision: https://reviews.llvm.org/D42999

llvm-svn: 326341
2018-02-28 17:48:55 +00:00
Alexey Bataev 9de940b93b [DEBUGINFO] Add flag for DWARF2 or less to use sections as references.
Summary:
Some targets does not support labels inside debug sections, but support
references in form `section +|- offset`. Patch adds initial support
for this. Also, this patch disables emission of all additional debug
  sections that may have labels inside of it (like pub sections and
  string tables).

Reviewers: probinson, echristo

Subscribers: JDevlieghere, llvm-commits

Differential Revision: https://reviews.llvm.org/D43627

llvm-svn: 326328
2018-02-28 15:02:59 +00:00
Scott Linder 16c7bdaf32 [DebugInfo] Support DWARF v5 source code embedding extension
In DWARF v5 the Line Number Program Header is extensible, allowing values with
new content types. In this extension a content type is added,
DW_LNCT_LLVM_source, which contains the embedded source code of the file.

Add new optional attribute for !DIFile IR metadata called source which contains
source text. Use this to output the source to the DWARF line table of code
objects. Analogously extend METADATA_FILE in Bitcode and .file directive in ASM
to support optional source.

Teach llvm-dwarfdump and llvm-objdump about the new values. Update the output
format of llvm-dwarfdump to make room for the new attribute on file_names
entries, and support embedded sources for the -source option in llvm-objdump.

Differential Revision: https://reviews.llvm.org/D42765

llvm-svn: 325970
2018-02-23 23:01:06 +00:00
Adrian Prantl 03dd6f5739 Use a stable topological sort in DwarfCompileUnit::createScopeChildrenDIE()
This addresses review feedback for D42940. The topological sort is
slightly more expensive but it can now also detect cycles in the
dependencies and actually works correctly.

rdar://problem/37217988

Differential Review: https://reviews.llvm.org/D43036

llvm-svn: 324677
2018-02-08 23:21:15 +00:00
Adrian Prantl c929f7ad42 Fix a crash when emitting DIEs for variable-length arrays
VLAs may refer to a previous DIE to express the DW_AT_count of their
type. Clang generates an artificial "vla_expr" variable for this. If
this DIE hasn't been created yet LLVM asserts. This patch fixes this
by sorting the local variables so that dependencies come before they
are needed. It also replaces the linear scan in DWARFFile with a
std::map, which can be faster.

Differential Revision: https://reviews.llvm.org/D42940

llvm-svn: 324412
2018-02-06 22:17:45 +00:00
Mikael Holmen a9e31537af [DebugInfo] Fix fragment offset emission order for symbol locations
Summary:
When emitting the location for a global variable with fragmented debug
expressions, make sure that the offset pieces, which represent
optimized-out parts of the variable, are emitted before their succeeding
fragments' expressions. Previously, if the succeeding fragment's
location was a symbol, the offset piece was emitted after, rather than
before, that symbol's expression. This effectively meant that the symbols
were associated with the wrong parts of the variable.

This fixes PR36085.

Patch by: David Stenberg

Reviewers: aprantl, probinson, dblaikie

Reviewed By: aprantl

Subscribers: JDevlieghere, llvm-commits

Tags: #debug-info

Differential Revision: https://reviews.llvm.org/D42527

llvm-svn: 323644
2018-01-29 12:37:30 +00:00
Sander de Smalen dc00becd1b [DebugInfo] Emit DWARF reference for DIVariable 'count' in DISubrange
Summary:
This patch implements the codegen of DWARF debug info for non-constant
'count' fields for DISubrange.

This is patch [2/3] in a series to extend LLVM's DISubrange Metadata
node to support debugging of C99 variable length arrays and vectors with
runtime length like the Scalable Vector Extension for AArch64. It is
also a first step towards representing more complex cases like arrays
in Fortran.

Reviewers: echristo, pcc, aprantl, dexonsmith, clayborg, kristof.beyls, dblaikie

Reviewed By: aprantl

Subscribers: fhahn, aemerson, rengolin, JDevlieghere, llvm-commits

Differential Revision: https://reviews.llvm.org/D41696

llvm-svn: 323323
2018-01-24 13:35:54 +00:00
Paul Robinson 612e89d74f [DWARFv5] CodeGen support for MD5 file checksums
Pass MD5 checksums through from IR to assembly/object files.
After this, getting Clang to compute the MD5 should be the last step
to supporting MD5 in the DWARF v5 line table header.

Differential Revision: https://reviews.llvm.org/D41926

llvm-svn: 322391
2018-01-12 19:17:50 +00:00
Paul Robinson 29f5f987f1 [DWARFv5] MC support for MD5 file checksums
Extend .file directive syntax to allow specifying an MD5 checksum for
the source file.  Emit the checksums in DWARF v5 line tables.

llvm-svn: 322134
2018-01-09 23:31:48 +00:00
David Blaikie b3bde2ea50 Fix a bunch more layering of CodeGen headers that are in Target
All these headers already depend on CodeGen headers so moving them into
CodeGen fixes the layering (since CodeGen depends on Target, not the
other way around).

llvm-svn: 318490
2017-11-17 01:07:10 +00:00
Jonas Devlieghere 294e689509 [DebugInfo] Fix potential CU mismatch for SubprogramScopeDIEs.
In constructAbstractSubprogramScopeDIE there can be a potential mismatch
between `this` and the CU of ContextDIE when a scope is shared between
two DISubprograms belonging to a different CU. In that case, `this` is
the CU that was specified in the IR, but the CU of ContextDIE is that of
the first subprogram that was emitted. This patch fixes the mismatch by
looking up the CU of ContextDIE, and switching to use that.

This fixes PR35212 (https://bugs.llvm.org/show_bug.cgi?id=35212)

Patch by Philip Craig!

Differential revision: https://reviews.llvm.org/D39981

llvm-svn: 318289
2017-11-15 10:57:05 +00:00
David Blaikie 1be62f0327 Move TargetFrameLowering.h to CodeGen where it's implemented
This header already includes a CodeGen header and is implemented in
lib/CodeGen, so move the header there to match.

This fixes a link error with modular codegeneration builds - where a
header and its implementation are circularly dependent and so need to be
in the same library, not split between two like this.

llvm-svn: 317379
2017-11-03 22:32:11 +00:00
Adrian Prantl a2f9e3a60f Deprecate DwarfUnit::addBlockByrefAddress().
The clang frontend already creates a DIExpression that replicates the
logic in addBlockByrefAddress() exactly, thus making this function
effectively unreachable. To guard against human error I'm hereby
marking the function with an assertion and let it hit the bots before
eventually removing it.

rdar://problem/31629055

llvm-svn: 315636
2017-10-12 22:54:36 +00:00
Peter Collingbourne 876da0294a Remove -generate-dwarf-pub-sections flag.
This flag is unnecessary for testing because we can get the coverage
we need by adjusting CU attributes.

Differential Revision: https://reviews.llvm.org/D37725

llvm-svn: 313079
2017-09-12 21:50:55 +00:00
Peter Collingbourne b52e23669c IR: Represent -ggnu-pubnames with a flag on the DICompileUnit.
This allows the flag to be persisted through to LTO.

Differential Revision: https://reviews.llvm.org/D37655

llvm-svn: 313078
2017-09-12 21:50:41 +00:00
Eugene Zelenko 6e07bfd0d9 [CodeGen] Fix some Clang-tidy modernize and Include What You Use warnings; other minor fixes (NFC).
llvm-svn: 311124
2017-08-17 21:26:39 +00:00
Adrian Prantl bd6d291c59 Assert that the offset of a DBG_VALUE is always 0. (NFC)
llvm-svn: 309834
2017-08-02 17:19:13 +00:00
Adrian Prantl 5577363a2c Remove the unused Offset field from MachineLocation (NFC)
rdar://problem/33580047

llvm-svn: 309831
2017-08-02 17:07:38 +00:00
Adrian Prantl 61b39b2aec Remove unused includes of MachineLocation.h (NFC)
llvm-svn: 309824
2017-08-02 15:32:18 +00:00
Adrian Prantl 2049c0d734 Remove unreachable code. (NFC)
MachineLocation::getOffset() always returns 0.

rdar://problem/33580047

llvm-svn: 309823
2017-08-02 15:22:17 +00:00
David Blaikie 2195e13676 DebugInfo: Ensure imported entities at the top level of an inlined function don't cause degenerate concrete definitions
Local imported entities at the top level of a subprogram were being
handled differently from those in nested scopes - that different
handling would cause pseudo concrete out-of-line definitions to be
created (but without any of their attributes, nor an abstract_origin) in
the case where there was no real concrete definition.

These local imported entities also only appeared in the concrete
definition where those imported entities in nested scopes appear in all
cases (abstract, concrete, and inlined). This change at least makes top
level case handle the same as the others - though there's a FIXME to
improve this to /only/ emit them into the abstract origin (though this
requires more plumbing - like the abstract subprogram and variable
handling that must defer population until the end of the unit to
discover if there is an abstract origin, or only a standalone concrete
definition).

llvm-svn: 309237
2017-07-27 00:06:53 +00:00
Adrian Prantl d63bfd218b Debug Info: Add a file: field to DIImportedEntity.
DIImportedEntity has a line number, but not a file field. To determine
the decl_line/decl_file we combine the line number from the
DIImportedEntity with the file from the DIImportedEntity's scope. This
does not work correctly when the parent scope is a DINamespace or a
DIModule, both of which do not have a source file.

This patch adds a file field to DIImportedEntity to unambiguously
identify the source location of the using/import declaration.  Most
testcase updates are mechanical, the interesting one is the removal of
the FIXME in test/DebugInfo/Generic/namespace.ll.

This fixes PR33822. See https://bugs.llvm.org/show_bug.cgi?id=33822
for more context.

<rdar://problem/33357889>
https://bugs.llvm.org/show_bug.cgi?id=33822

Differential Revision: https://reviews.llvm.org/D35583

llvm-svn: 308398
2017-07-19 00:09:54 +00:00
Wolfgang Pieb e60147c89f [DWARF] Move a couple of member functions to the DWARFUnit baseclass. NFC.
Reviewer: dblaikie

Differential revision: https://reviews.llvm.org/D34765

llvm-svn: 306771
2017-06-30 00:27:45 +00:00
Florian Hahn ffc498dfcc Align definition of DW_OP_plus with DWARF spec [3/3]
Summary:
This patch is part of 3 patches that together form a single patch, but must be introduced in stages in order not to break things.
 
The way that LLVM interprets DW_OP_plus in DIExpression nodes is basically that of the DW_OP_plus_uconst operator since LLVM expects an unsigned constant operand. This unnecessarily restricts the DW_OP_plus operator, preventing it from being used to describe the evaluation of runtime values on the expression stack. These patches try to align the semantics of DW_OP_plus and DW_OP_minus with that of the DWARF definition, which pops two elements off the expression stack, performs the operation and pushes the result back on the stack.
 
This is done in three stages:
• The first patch (LLVM) adds support for DW_OP_plus_uconst.
• The second patch (Clang) contains changes all its uses from DW_OP_plus to DW_OP_plus_uconst.
• The third patch (LLVM) changes the semantics of DW_OP_plus and DW_OP_minus to be in line with its DWARF meaning. This patch includes the bitcode upgrade from legacy DIExpressions.

Patch by Sander de Smalen.

Reviewers: echristo, pcc, aprantl

Reviewed By: aprantl

Subscribers: fhahn, javed.absar, aprantl, llvm-commits

Differential Revision: https://reviews.llvm.org/D33894

llvm-svn: 305386
2017-06-14 13:14:38 +00:00
David Blaikie b3cee2fb42 DebugInfo: Produce debug_{gnu_}pub{names,types} entries when explicitly requested, even in -gmlt or when empty
Turns out gold doesn't use the DW_AT_GNU_pubnames to decide whether to
parse the rest of the DIEs when building gdb-index. This causes gold to
trip over LLVM's output when there are DW_FORM_ref_addr present.

Gold does use the presence of a debug_gnu_pub{names,types} entry for the
CU to skip parsing the debug_info portion, so make sure that's included
even when empty (technically, when empty there couldn't be any ref_addr
anyway - it only came up when gmlt didn't produce any (even non-empty)
pubnames - but given what that reveals about gold's implementation, this
seems like a good thing to do for consistency).

llvm-svn: 303894
2017-05-25 18:50:28 +00:00