Commit Graph

11389 Commits

Author SHA1 Message Date
Rui Ueyama 3d354081e0 Simplify. NFC.
- Removed redundant `llvm::`
 - Typedef a long type name
 - Initialize members by member initializers

llvm-svn: 344427
2018-10-12 22:44:06 +00:00
Rui Ueyama f3fad55787 Remove `Type` parameter from SymbolTable::insert(). NFC.
`Type` parameter was used only to check for TLS attribute mismatch,
but we can do that when we actually replace symbols, so we don't need
to type as an argument. This change should simplify the interface of
the symbol table a bit.

llvm-svn: 344394
2018-10-12 18:29:18 +00:00
Zachary Turner 5bba1cafbe Better support for POSIX paths in PDBs.
This a resubmission of a patch which was previously reverted
due to breaking several lld tests.  The issues causing those
failures have been fixed, so the patch is now resubmitted.

---Original Commit Message---

While it doesn't make a *ton* of sense for POSIX paths to be
in PDBs, it's possible to occur in real scenarios involving
cross compilation.

The tools need to be able to handle this, because certain types
of debugging scenarios are possible without a running process
and so don't necessarily require you to be on a Windows system.
These include post-mortem debugging and binary forensics (e.g.
using a debugger to disassemble functions and examine symbols
without running the process).

There's changes in clang, LLD, and lldb in this patch.  After
this the cross-platform disassembly and source-list tests pass
on Linux.

Furthermore, the behavior of LLD can now be summarized by a much
simpler rule than before: Unless you specify /pdbsourcepath and
/pdbaltpath, the PDB ends up with paths that are valid within
the context of the machine that the link is performed on.

Differential Revision: https://reviews.llvm.org/D53149

llvm-svn: 344377
2018-10-12 17:26:19 +00:00
Rui Ueyama 2e9d40d5f4 [lld] Add more complete support for the INCLUDE command.
Patch by Ian Tessier.

This change adds INCLUDE support to the MEMORY and SECTION commands, and
to output sections, as per:

https://sourceware.org/binutils/docs/ld/File-Commands.html#File-Commands

Differential Revision: https://reviews.llvm.org/D52951

llvm-svn: 344368
2018-10-12 17:07:32 +00:00
Zachary Turner 9f169afab2 Make YAML quote forward slashes.
If you have the string /usr/bin, prior to this patch it would not
be quoted by our YAML serializer.  But a string like C:\src would
be, due to the presence of a backslash.  This makes the quoting
rules of basically every single file path different depending on
the path syntax (posix vs. Windows).

While technically not required by the YAML specification to quote
forward slashes, when the behavior of paths is inconsistent it
makes it difficult to portably write FileCheck lines that will
work with either kind of path.

Differential Revision: https://reviews.llvm.org/D53169

llvm-svn: 344359
2018-10-12 16:31:20 +00:00
Zachary Turner 9c544199cf Revert "Make YAML quote forward slashes."
This reverts commit b86c16ad8c97dadc1f529da72a5bb74e9eaed344.

This is being reverted because I forgot to write a useful
commit message, so I'm going to resubmit it with an actual
commit message.

llvm-svn: 344358
2018-10-12 16:31:08 +00:00
Zachary Turner ec234052a6 Make YAML quote forward slashes.
llvm-svn: 344357
2018-10-12 16:24:09 +00:00
George Rimar 4cb05713de [ELF] - Remove unused variable. NFC.
It triggered a bot failture somehow today:
http://lab.llvm.org:8011/builders/lld-perf-testsuite/builds/7993

llvm-svn: 344344
2018-10-12 13:39:35 +00:00
George Rimar fa91327b51 [ELF] - Remove dead declaration. NFC.
MipsGotSection::FileGot::isOverflow()
was a dead declararion.

llvm-svn: 344342
2018-10-12 13:25:25 +00:00
Rui Ueyama b0d8502049 Remove SymbolTable::addAbsolute().
addAbsolute() could be implemented as a non-member function.

llvm-svn: 344305
2018-10-11 22:15:41 +00:00
Rui Ueyama 936cfa86e5 Remove `else` after `return`.
llvm-svn: 344302
2018-10-11 21:57:52 +00:00
Eli Friedman 8b44cc21c6 [ELF] Fix link failure with Android compressed relocation support.
Android uses a compressed relocation format, which means the size of the
relocation section isn't predictable based on the number of relocations,
and can vary if the layout changes in any way. To deal with this, the
linker normally runs multiple passes until the layout converges.

The layout should converge if the size of the compressed
relocation section increases monotonically: if the size of an encoded
offset increases by one byte, the larget value which can be encoded is
multiplied by 128, so the representable offsets grow much faster than
the size of the section itself.

The problem here is that there is no code to ensure the size of the
section doesn't decrease.  If the size of the relocation section
decreases, the relative offsets can increase due to alignment
restrictions, so that can force the size of the relocation section to
increase again.  The end result is an infinite loop; the loop gets cut
off after 10 iterations with the message "thunk creation not
converged".

To avoid this issue, this patch adds padding to the end of the
relocation section if its size would decrease.  The extra
padding is harmless because of the way the format is defined:
decoding stops after it reaches the number of relocations specified
in the section's header.

Differential Revision: https://reviews.llvm.org/D53003

llvm-svn: 344300
2018-10-11 21:43:06 +00:00
Rui Ueyama 2600e0946b Rename SymbolTable::addRegular -> SymbolTable::addDefined.
We have addAbsolute, addBitcode, addCommon, etc. addRegular looked a
bit inconsistent.

llvm-svn: 344294
2018-10-11 20:43:01 +00:00
Rui Ueyama cf41adaaa0 Remove unused default arguments.
llvm-svn: 344292
2018-10-11 20:38:34 +00:00
Rui Ueyama c7497d3ac5 Remove SymbolTable::addUndefined<ELF32LE>(StringRef).
Because we can implement the function as a non-member function.

llvm-svn: 344290
2018-10-11 20:34:29 +00:00
Zachary Turner e8a6c3eb96 Revert SymbolFileNativePDB plugin.
This was originally causing some test failures on non-Windows
platforms, which required fixes in the compiler and linker.  After
those fixes, however, other tests started failing.  Reverting
temporarily until I can address everything.

llvm-svn: 344279
2018-10-11 18:45:44 +00:00
Zachary Turner e502f8b315 Better support for POSIX paths in PDBs.
While it doesn't make a *ton* of sense for POSIX paths to be
in PDBs, it's possible to occur in real scenarios involving
cross compilation.

The tools need to be able to handle this, because certain types
of debugging scenarios are possible without a running process
and so don't necessarily require you to be on a Windows system.
These include post-mortem debugging and binary forensics (e.g.
using a debugger to disassemble functions and examine symbols
without running the process).

There's changes in clang, LLD, and lldb in this patch.  After
this the cross-platform disassembly and source-list tests pass
on Linux.

Furthermore, the behavior of LLD can now be summarized by a much
simpler rule than before: Unless you specify /pdbsourcepath and
/pdbaltpath, the PDB ends up with paths that are valid within
the context of the machine that the link is performed on.

Differential Revision: https://reviews.llvm.org/D53149

llvm-svn: 344269
2018-10-11 18:01:55 +00:00
Martin Storsjo 8cc0f71261 [COFF] Add and use a Wordsize field in Config. NFCI.
Differential Revision: https://reviews.llvm.org/D53143

llvm-svn: 344265
2018-10-11 17:45:58 +00:00
Martin Storsjo 21eb363302 [COFF] Set proper pointer size alignment for LocalImportChunk
When these are accessed with load/store instructions on ARM64,
it becomes strictly necessary to have them properly aligned.

This fixes PR39228.

Differential Revision: https://reviews.llvm.org/D53128

llvm-svn: 344264
2018-10-11 17:45:51 +00:00
George Rimar 3368643f5e [ELF] - Set sh_info and sh_link for .rela.plt sections.
This is https://bugs.llvm.org/show_bug.cgi?id=37538,

Currently, LLD may set both sh_link and sh_info for
.rela.plt section to zero when we have only .rela.iplt section part used.

ELF spec (https://docs.oracle.com/cd/E19683-01/816-1386/chapter6-94076/index.html)
says that for SHT_REL and SHT_RELA, sh_link references the associated symbol table
and sh_info the "section to which the relocation applies."

When we set the sh_link field, for the regular case we use the .dynsym index.
For .rela.iplt sections, it is unclear what is the associated symbol table,
because R_*_RELATIVE relocations do not use symbol names and we might have no
.dynsym section at all so this patch uses .symtab section index.

Differential revision: https://reviews.llvm.org/D52830

llvm-svn: 344226
2018-10-11 08:25:35 +00:00
Fangrui Song a535e0543f Eliminate dependency to formatv(). NFC.
llvm-svn: 344212
2018-10-11 00:58:00 +00:00
Rui Ueyama 3c4344810a Make a member function private and rename it to avoid function overloading.
llvm-svn: 344196
2018-10-10 22:49:29 +00:00
Fangrui Song 11ca54f49c [ELF] Don't warn on undefined symbols if UnresolvedPolicy::Ignore is used
Summary:
Add a condition UnresolvedPolicy::Ignore to elf::warnUnorderedSymbol to suppress Sym->isUndefined() warnings from both

1) --symbol-ordering-file=
2) .llvm.call-graph-profile

If --unresolved-symbols=ignore-all is used,

  no "undefined symbol" error/warning is emitted. It makes sense to not warn unorderable symbols.

Otherwise,

  If an executable is linked, the default policy UnresolvedPolicy::ErrorOrWarn will issue a "undefined symbol" error. The unorderable symbol warning is redundant.

  If a shared object is linked, it is possible that only part of object files are used and some symbols are left undefined. The warning is not very necessary.
    In particular for .llvm.call-graph-profile, when linking a shared object, a call graph profile may contain undefined symbols. This case generated a warning before but it will be suppressed by this patch.

Reviewers: ruiu, davidxl, espindola

Reviewed By: ruiu

Subscribers: grimar, emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D53044

llvm-svn: 344195
2018-10-10 22:48:57 +00:00
Rui Ueyama 9ae88c64fa Eliminate dependency to formatv(). NFC.
llvm-svn: 344177
2018-10-10 20:29:29 +00:00
Martin Storsjo 33d43ff851 [COFF] Look for libfoo.a if foo.lib is specified, for MinGW
This allows using #pragma comment(lib, "foo") in MinGW built code,
if built with -fms-extensions. (This works for system libraries and
static libraries only, as it doesn't try to look for .dll.a. As
ld.bfd doesn't support embedded defaultlib directives, this isn't
in widespread use among mingw users.)

Differential Revision: https://reviews.llvm.org/D53017

llvm-svn: 344124
2018-10-10 09:00:10 +00:00
Martin Storsjo 803b37ad5d [MinGW] Pass libpath to the COFF linker
This is necessary for handling defaultlib directives embedded in
object files, unless they use an absolute path.

Differential Revision: https://reviews.llvm.org/D53015

llvm-svn: 344123
2018-10-10 09:00:03 +00:00
Fangrui Song 2043a58abe Adapt OptTable::PrintHelp change in D51009
Summary: Before, OptTable::PrintHelp append "[options] <inputs>" to its parameter `Help`. It is more flexible to change its semantic to `Usage` and let user customize the usage line.

Reviewers: rupprecht, ruiu, espindola

Reviewed By: rupprecht

Subscribers: emaste, sbc100, arichardson, aheejin, llvm-commits

Differential Revision: https://reviews.llvm.org/D53054

llvm-svn: 344099
2018-10-10 00:15:36 +00:00
Rui Ueyama 71cdbb7fe6 Merge two overloaded functions into one function. NFC.
llvm-svn: 344089
2018-10-09 22:44:53 +00:00
Rui Ueyama e65cb4889e Return early. NFC.
llvm-svn: 344088
2018-10-09 22:44:42 +00:00
Rui Ueyama 2b53b4bea6 Attempt to fix ubsan.
Previously, we cast a pointer to Elf{32,64}_Chdr like this

  auto *Hdr = reinterpret_cast<const ELF64_Chdr>(Ptr);

and read from its members like this

  read32(&Hdr->ch_size);

I was thinking that this does not violate alignment requirement,
since &Hdr->ch_size doesn't really access memory, but seems like
it is a violation in terms of C++ spec (?)

In this patch, I use a different struct that allows unaligned access.

llvm-svn: 344083
2018-10-09 21:41:53 +00:00
Rui Ueyama e3ccd28660 Calculate an offset only once. NFC.
llvm-svn: 344076
2018-10-09 20:29:24 +00:00
Rui Ueyama fbc629702d Remove redundant `Symtab->`.
`SymbolTable` is a singleton class and is a global variable for the
unique instance, so we can always refer the symtab by `Symtab->`.
However, we don't need to use the global varaible from member functions
of SymbolTable class.

llvm-svn: 344075
2018-10-09 20:22:18 +00:00
Rui Ueyama 714abece2b Simplify. NFC.
llvm-svn: 344074
2018-10-09 20:16:16 +00:00
Rui Ueyama 659cff37d6 Remove a use of template to make code less abstracted.
Sometimes, code that is a bit longer but doesn't use template is
easier to understand than code that uses template.

llvm-svn: 344072
2018-10-09 19:54:32 +00:00
Zachary Turner 2be11c0260 Fix lld test.
I removed this output from the dumper because it was non-portable,
but I didn't update the test which checked the output.

llvm-svn: 344066
2018-10-09 18:35:06 +00:00
Nico Weber e1b9331d29 lld-link: attempt to fix tests on Windows after r344061.
llvm-svn: 344065
2018-10-09 18:19:09 +00:00
Rui Ueyama c2921f002e Add an entry to the release notes.
llvm-svn: 344062
2018-10-09 17:53:33 +00:00
Nico Weber 4764bb2cb1 lld-link: Use /pdbsourcepath: for more places when present.
/pdbsourcepath: was added in https://reviews.llvm.org/D48882 to make it
possible to have relative paths in the debug info that clang-cl writes.
lld-link then makes the paths absolute at link time, which debuggers require.
This way, clang-cl's output is independent of the absolute path of the build
directory, which is useful for cacheability in distcc-like systems.

This patch extends /pdbsourcepath: (if passed) to also be used for:

1. The "cwd" stored in the env block in the pdb is /pdbsourcepath: if present
2. The "exe" stored in the env block in the pdb is made absolute relative
   to /pdbsourcepath: instead of the cwd
3. The "pdb" stored in the env block in the pdb is made absolute relative
   to /pdbsourcepath: instead of the cwd
4. For making absolute paths to .obj files referenced from the pdb

/pdbsourcepath: is now useful in three scenarios (the first one already working
before this change):

1. When building with full debug info, passing the real build dir to
   /pdbsourcepath: allows having clang-cl's output to be independent
   of the build directory path. This patch effectively doesn't change
   behavior for this use case (assuming the cwd is the build dir).

2. When building without compile-time debug info but linking with /debug,
   a fake fixed /pdbsourcepath: can be passed to get symbolized stacks
   while making the pdb and exe independent of the current build dir.
   For this two work, lld-link needs to be invoked with relative paths for
   the lld-link invocation itself (for "exe"), for the pdb output name, the exe
   output name (for "pdb"), and the obj input files, and no absolute path
   must appear on the link command (for "cmd" in the pdb's env block).
   Since no full debug info is present, it doesn't matter that the absolute
   path doesn't exist on disk -- we only get symbols in stacks.

3. When building production builds with full debug info that don't have
   local changes, and that get source indexed and their pdbs get uploaded
   to a symbol server. /pdbsourcepath: again makes the build output independent
   of the current directory, and the fixed path passed to /pdbsourcepath: can
   be given the source indexing transform so that it gets mapped to a
   repository path. This has the same requirements as 2.

This patch also makes it possible to create PDB files containing Windows-style
absolute paths when cross-compiling on a POSIX system.

Differential Revision: https://reviews.llvm.org/D53021

llvm-svn: 344061
2018-10-09 17:52:25 +00:00
Nico Weber 9d7524160a lld-link: Implement support for %_PDB% and %_EXT% for /pdbaltpath:.
Warn that references to regular env vars are ignored.

Fixes PR38940.

Differential Revision: https://reviews.llvm.org/D52942

llvm-svn: 344003
2018-10-08 23:06:05 +00:00
Rui Ueyama 9b5a495d48 Fix a broken buildbot.
llvm-svn: 343983
2018-10-08 17:24:29 +00:00
Rui Ueyama e28c146423 Avoid unnecessary buffer allocation and memcpy for compressed sections.
Previously, we uncompress all compressed sections before doing anything.
That works, and that is conceptually simple, but that could results in
a waste of CPU time and memory if uncompressed sections are then
discarded or just copied to the output buffer.

In particular, if .debug_gnu_pub{names,types} are compressed and if no
-gdb-index option is given, we wasted CPU and memory because we
uncompress them into newly allocated bufers and then memcpy the buffers
to the output buffer. That temporary buffer was redundant.

This patch changes how to uncompress sections. Now, compressed sections
are uncompressed lazily. To do that, `Data` member of `InputSectionBase`
is now hidden from outside, and `data()` accessor automatically expands
an compressed buffer if necessary.

If no one calls `data()`, then `writeTo()` directly uncompresses
compressed data into the output buffer. That eliminates the redundant
memory allocation and redundant memcpy.

This patch significantly reduces memory consumption (20 GiB max RSS to
15 Gib) for an executable whose .debug_gnu_pub{names,types} are in total
5 GiB in an uncompressed form.

Differential Revision: https://reviews.llvm.org/D52917

llvm-svn: 343979
2018-10-08 16:58:59 +00:00
Sid Manning 307c7901d0 [ELF][HEXAGON] Add R_HEX_GOT_16_X support
Differential Revision: https://reviews.llvm.org/D52909

llvm-svn: 343972
2018-10-08 15:32:46 +00:00
Petr Hosek 62f6462bf9 [llvm-nm] Write "no symbol" output to stderr
This matches the output of binutils' nm and ensures that any scripts
or tools that use nm and expect empty output in case there no symbols
don't break.

Differential Revision: https://reviews.llvm.org/D52943

llvm-svn: 343887
2018-10-05 21:10:03 +00:00
Martin Storsjo 08ab568aaa [COFF] Do MinGW specific entry/subsystem inference
ld.bfd doesn't do any inference of subsystem; unless the windows
subsystem is specified, the console subsystem is used.

For the console subsystem, the entry point is called mainCRTStartup,
regardless of whether the the user code entry point is main or wmain.
The same goes for the windows subsystem, where the entry point always
is WinMainCRTStartup, for both WinMain and wWinMain in user code.

One detail that we don't emulate, is that if the inferred entry point
is undefined, ld.bfd silently just sets the entry point to the start
of the image. And if an explicit entry point is set, but it is
undefined, the link still succeeds but the linker warns about the
entry point not being found.

Differential Revision: https://reviews.llvm.org/D52931

llvm-svn: 343879
2018-10-05 19:43:24 +00:00
Martin Storsjo db9148d21d [docs] Mention some notable feature in the release notes
Differential Revision: https://reviews.llvm.org/D52908

llvm-svn: 343878
2018-10-05 19:43:20 +00:00
Martin Storsjo cab6dafc04 [COFF] Cope with GCC produced weak aliases referring to comdat functions
For certain cases of inline functions written to comdat sections,
GCC 5.x produces a weak symbol in addition, which would end up
undefined in some cases.

This no longer seems to happen with GCC 6.x or newer though.

Differential Revision: https://reviews.llvm.org/D52602

llvm-svn: 343877
2018-10-05 19:43:16 +00:00
Alexandre Ganea 149de8de19 [LLD][COFF] Fix ordering of CRT global initializers in COMDAT sections
(patch by Benoit Rousseau)

This patch fixes a bug where the global variable initializers were sometimes not invoked in the correct order when it involved a C++ template instantiation.

Differential Revision: https://reviews.llvm.org/D52749

llvm-svn: 343847
2018-10-05 12:56:46 +00:00
Ed Maste bf378b808a ReleaseNotes: remove superfluous 's' in 'can promotes'
llvm-svn: 343820
2018-10-04 21:37:32 +00:00
Sid Manning 261eec5fa5 [ELF][HEXAGON] Add support for GOT relocations.
The GOT is referenced through the symbol _GLOBAL_OFFSET_TABLE_ .

The relocation added calculates the offset into the global offset table for
the entry of a symbol.  In order to get the correct TargetVA I needed to
create an new relocation expression, HEXAGON_GOT.  It does
Sym.getGotVA() - In.GotPlt->getVA().

Differential Revision: https://reviews.llvm.org/D52744

llvm-svn: 343784
2018-10-04 14:54:17 +00:00
George Rimar f76dffb90f [ELF] - Simplify. NFCI.
Assign the `Link` to parent directly.

llvm-svn: 343762
2018-10-04 09:31:15 +00:00
Matt Morehouse 8d53ab5e7a Use std::make_pair rather than brace initialization.
r343732 broke the Windows bot.  Seems like the compiler on that bot
doesn't like brace initialization.

llvm-svn: 343749
2018-10-04 00:35:24 +00:00
Shoaib Meenai 509230f68d [ELF] Fix typo. NFC
llvm-svn: 343748
2018-10-04 00:07:59 +00:00
Shoaib Meenai 6883d882f1 [ELF] Fix crash on invalid undefined local symbols
r320770 made LLD handle invalid DSOs where local symbols were found in
the global part of the symbol table. Unfortunately, it didn't handle the
case where those local symbols were also undefined, and r326242 exposed
an assertion failure in that case. Just warn on that case instead of
crashing, by moving the local binding check before the undefined symbol
addition.

The input file for the test is crafted by hand, since I don't know of
any tool that would produce such a broken DSO. I also don't understand
what it even means for a symbol to be undefined but have STB_LOCAL
binding - I don't think that combination makes any sense - but we have
found broken DSOs of this nature that we were linking against. I've
included detailed instructions on how to produce the DSO in the test.

Differential Revision: https://reviews.llvm.org/D52815

llvm-svn: 343745
2018-10-03 23:53:11 +00:00
Jordan Rupprecht dd0f98972d [llvm-nm] Update lld tests based on changed llvm-nm output
llvm-svn: 343743
2018-10-03 23:39:59 +00:00
Derek Schuff 371842b853 [WebAssembly] Refactor use of signatures
Update use of WebAssemblySignature to go along with D52580

Differential Revision: https://reviews.llvm.org/D52622

llvm-svn: 343734
2018-10-03 22:25:32 +00:00
Rui Ueyama 3ed33eade0 Minor refacotring of Relocations.cpp. NFC.
This patch splits ThunkCreator::mergeThunks into two smaller functions.
Also adds blank lines to various places so that the code doesn't look
too dense.

llvm-svn: 343732
2018-10-03 22:20:26 +00:00
Sean Fertile 98da20f0fb [PPC64] Test documenting toc-restore after interposable recursive call. [NFC]
A test verifying that toc restores are properly inserted following recursive
calls, as well as briefly describing why they are needed.

Differential Revision: https://reviews.llvm.org/D52564

llvm-svn: 343729
2018-10-03 21:58:44 +00:00
Sean Fertile 7cbe41f2c7 [PPC64] Add test documenting toc-restore when linking with -Bsymbolic. [NFC]
Differential Revision: https://reviews.llvm.org/D52523

llvm-svn: 343728
2018-10-03 21:58:42 +00:00
Martin Storsjo 2657200274 [COFF] Cope with weak aliases produced by GNU tools
When GNU tools create a weak alias, they produce a strong symbol
named .weak.<weaksymbol>.<relatedstrongsymbol>.

GNU ld allows many such weak alternatives for the same weak symbol, and
the linker picks the first one encountered.

This can't be reproduced by assembling from .s files, since llvm-mc
produces symbols named .weak.<weaksymbol>.default in these cases.

Differential Revision: https://reviews.llvm.org/D52601

llvm-svn: 343704
2018-10-03 18:31:53 +00:00
Nico Weber d377826277 lld-link: Several tweaks to default entry point selection.
Three related changes:

1. link.exe uses the presence of main and wmain to decide if it should call
   mainCRTStartup or wmainCRTStartup, even if /nodefaultlib is passed. For
   compatibility, remove FindMain logic.

2. Default to the non-wide entrypoint if main is not found. This has two effects:

2a. In normal links, lld-link now prints

        lld-link: error: undefined symbol: _main
        >>> referenced by f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:78
        >>>               libcmt.lib(exe_main.obj):("int __cdecl invoke_main(void)" (?invoke_main@@YAHXZ))
        >>> referenced by f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:283
        >>>               libcmt.lib(exe_main.obj):("int __cdecl __scrt_common_main_seh(void)" (?__scrt_common_main_seh@@YAHXZ))

    instead of

        lld-link: error: entry point must be defined

    This is arguably a better error message, since it now mentions that _main is
    missing. (This matches link.exe's diagnostic in this case.)

2b. With /nodefautlib, we now default to mainCRTStartup if no main() is
    present, again matching link.exe. This makes r337407 obsolete.

This means if you have a cc file containing both mainCRTStartup and
wmainCRTStartup and you pass /nodefaultlib /subsystem:console, lld-link will
now call mainCRTStartup, matching link.exe

3. Print a warning if both main and wmain are present, similar to link.exe's
   LNK4067.

Differential Revision: https://reviews.llvm.org/D52832

llvm-svn: 343698
2018-10-03 17:01:39 +00:00
George Rimar db2e641fd7 [ELF] - Fix BB after r343668
This stops testing the value of .rela.plt section offset.

Also makes _start global to eliminate
'cannot find entry symbol _start' warning.

llvm-svn: 343669
2018-10-03 09:59:08 +00:00
George Rimar f79a8ef2ae [ELF] - Do not forget to include to .dymsym symbols that were converted to Defined.
This is the fix for
"Bug 39104 - LLD links incorrect ELF executable if version script contains "local: *;"
(https://bugs.llvm.org/show_bug.cgi?id=39104).

The issue happens when we have non-PIC program call to function in a shared library.
(for example, the PR above has R_X86_64_PC32 relocation against __libc_start_main)

LLD converts symbol to Defined in that case with the use of replaceWithDefined()

The issue is that after above we create a broken relocation because do not
include the symbol into .dynsym.

That happens when the version script is used because we treat the symbol as
STB_LOCAL if the following condition match:
VersionId == VER_NDX_LOCAL && isDefined() and do not include it to
.dynsym because of that. Patch fixes the issue.

Differential revision: https://reviews.llvm.org/D52724

llvm-svn: 343668
2018-10-03 09:33:00 +00:00
George Rimar 3832d7c25d [LLD] - Do not crash when reporting errors when .debug_line_str (DWARF5) is used
Imagine we have the following code:

int foo();
int main() { return foo(); }

It will crash if you try to compile it with
`clang -O0 -gdwarf-5 test.cpp -o test -g -fuse-ld=lld`

The crash happens inside the LLVM DWARF parser because LLD does not provide
the .debug_line_str section. At the same time for correct parsing and reporting,
we anyways need to provide this section from our side.

The patch fixes the issue.

llvm-svn: 343667
2018-10-03 08:59:46 +00:00
Ali Tamur 63830b2794 Introduce a flag to warn when ifunc symbols are used with text relocations.
Summary:
This patch adds a new flag, --warn-ifunc-textrel, to work around a glibc bug. When a code with ifunc symbols is used to produce an object file with text relocations, lld always succeeds. However, if that object file is linked using an old version of glibc, the resultant binary just crashes with segmentation fault when it is run (The bug is going to be corrected as of glibc 2.19).

Since there is no way to tell beforehand what library the object file will be linked against in the future, there does not seem to be a fool-proof way for lld to give an error only in cases where the binary will crash. So, with this change (dated 2018-09-25), lld starts to give a warning, contingent on a new command line flag that does not have a gnu counter part. The default value for --warn-ifunc-textrel is false, so lld behaviour will not change unless the user explicitly asks lld to give a warning. Users that link with a glibc library with version 2.19 or newer, or does not use ifunc symbols, or does not generate object files with text relocations do not need to take any action. Other users may consider to start passing warn-ifunc-textrel to lld to get early warnings.

Reviewers: ruiu, espindola

Reviewed By: ruiu

Subscribers: grimar, MaskRay, markj, emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D52430

llvm-svn: 343628
2018-10-02 20:30:22 +00:00
Diogo N. Sampaio a35e55eff9 [NFC][BUG-FIX][ARM] Add missing data symbol
llvm rL343594: [ARM] Emmit data symbol
for constant pool data fixed a bug that ommited
required data symbols.
Such change breaked a test case in lld:
test/ELF/arm-thunk-largesection.s

llvm-svn: 343604
2018-10-02 16:53:12 +00:00
Michael J. Spencer 8222f902ca [ELF] Read the call graph profile from object files.
This uses the call graph profile embedded in the object files to construct the call graph.

This is read from a SHT_LLVM_CALL_GRAPH_PROFILE (0x6fff4c02) section as (uint32_t, uint32_t, uint64_t) tuples as (from symbol index, to symbol index, weight).

Differential Revision: https://reviews.llvm.org/D45850

llvm-svn: 343552
2018-10-02 00:17:15 +00:00
Sid Manning 490429d069 [ELF] [HEXAGON] Add support for PLT_B22_PCREL and HEX_32_PCREL
Update testcase.

Differential Revision: https://reviews.llvm.org/D52734

llvm-svn: 343515
2018-10-01 18:27:26 +00:00
Rui Ueyama 1e591d807b Add an explanation about cross linking.
Differential Revision: https://reviews.llvm.org/D52567

llvm-svn: 343495
2018-10-01 16:41:58 +00:00
James Henderson 194a4eb8f7 Fix typo in LLD man page
llvm-svn: 343449
2018-10-01 09:57:20 +00:00
Martin Storsjo 0f8f0d6d1d [COFF] In MinGW mode, ignore relocations against a discarded section
When GCC produces a jump table as part of a comdat function, the
jump table itself is produced as plain non-comdat rdata section. When
linked with ld.bfd, all of those rdata sections are kept, with
relocations unchanged in the sections that refer to discarded comdat
sections.

This has been observed with at least GCC 5.x and 7.x.

Differential Revision: https://reviews.llvm.org/D52600

llvm-svn: 343422
2018-09-30 18:31:03 +00:00
Alexandre Ganea 91def5cc6a [LLD][COFF] Fix pdb loading when the path points to a removable device
Differential Revision: https://reviews.llvm.org/D52666

llvm-svn: 343366
2018-09-28 21:53:40 +00:00
Sam Clegg 8b0b48f343 [WebAssembly] Preserve function signatures during LTO
With LTO when and undefined function (with a known signature)
in replaced by a defined bitcode function we were loosing the
signature information (since bitcode functions don't have
signatures).

With this change we preserve the original signature from the
undefined function and verify that the post LTO compiled
function has the correct signature.

This change improves the error handling in the case where
there is a signature mismatch with a function defined in
a bitcode file.

Differential Revision: https://reviews.llvm.org/D50721

llvm-svn: 343340
2018-09-28 16:50:14 +00:00
Sid Manning fc50e63a2a [ELF][HEXAGON] Add support for dynamic libraries
Write out the PLT header and stub.
Hexagon uses RELA relocations.

Differential Revision: https://reviews.llvm.org/D52317

llvm-svn: 343320
2018-09-28 14:09:16 +00:00
Sam Clegg 305b0343ce [WebAssembly] Add --[no]-export-dynamic to replace --export-default
In a very recent change I introduced a --no-export-default flag
but after conferring with others it seems that this feature already
exists in gnu GNU ld and lld in the form the --export-dynamic flag
which is off by default.

This change replaces export-default with export-dynamic and also
changes the default to match the traditional linker behaviour.

Now, by default, only the entry point is exported.  If other symbols
are required by the embedder then --export-dynamic or --export can
be used to export all visibility hidden symbols or individual
symbols respectively.

This change touches a lot of tests that were relying on symbols
being exported by default.  I imagine it will also effect many
users but do think the change is worth it match of the traditional
behaviour and flag names.

Differential Revision: https://reviews.llvm.org/D52587

llvm-svn: 343265
2018-09-27 21:06:25 +00:00
Peter Smith fb5a5d09fe [COFF] Add missing Requires x86 to fix buildbot
Add REQUIRES: x86 to pdb-debug-f.s as this is causing the Arm and
AArch64 buildbots to fail as they do not have the x86 backend.

Differential Revision: https://reviews.llvm.org/D52606

llvm-svn: 343196
2018-09-27 12:07:47 +00:00
Sam Clegg 4aad12ce0b [WebAssembly] Update Config member to match command line option
Subscribers: dschuff, jgravelle-google, aheejin, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D50976

llvm-svn: 343157
2018-09-27 00:46:54 +00:00
Sam Clegg bd37e09355 Revert "[WebAssembly] Update docs"
This change reverts rL343155.  It broke the builtbot, even though
it works for me locally:
http://lab.llvm.org:8011/builders/lld-sphinx-docs/builds/26336

Must be a sphinx version issue I guess.

llvm-svn: 343156
2018-09-27 00:42:49 +00:00
Sam Clegg 77ab7c1b30 [WebAssembly] Update docs
Differential Revision: https://reviews.llvm.org/D52048

llvm-svn: 343155
2018-09-27 00:22:24 +00:00
Fangrui Song dbaeec6892 [ELF] llvm::sort(C.begin(), C.end(), ...) -> llvm::sort(C, ...)
Summary: The convenience wrapper in STLExtras is available since rL342102.

Reviewers: ruiu, espindola

Subscribers: emaste, arichardson, mgrang, llvm-commits

Differential Revision: https://reviews.llvm.org/D52569

llvm-svn: 343146
2018-09-26 20:54:42 +00:00
Ryan Prichard ed5bb932a2 Allow later -z name=<int> args to override earlier args
Summary:
lld already gives later -z options precedence in getZFlag().

This matches the behavior of ld.bfd and ld.gold, where later options
override earlier ones. (I tested with -z max-page-size and -z stack-size.)

Reviewers: ruiu, espindola, grimar

Reviewed By: ruiu, grimar

Subscribers: grimar, emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D52526

llvm-svn: 343145
2018-09-26 20:50:39 +00:00
Ryan Prichard b7c8d2d405 [AArch64] Fix range check of R_AARCH64_TLSLE_ADD_TPREL_HI12
Summary:
An AArch64 LE relocation is a positive ("variant 1") offset. This
relocation is used to write the upper 12 bits of a 24-bit offset into an
add instruction:

    add x0, x0, :tprel_hi12:v1

The comment in the ARM docs for R_AARCH64_TLSLE_ADD_TPREL_HI12 is:

"Set an ADD immediate field to bits [23:12] of X; check 0 <= X < 2^24."

Reviewers: javed.absar, espindola, ruiu, peter.smith, zatrazz

Reviewed By: ruiu

Subscribers: emaste, arichardson, kristof.beyls, llvm-commits

Differential Revision: https://reviews.llvm.org/D52525

llvm-svn: 343144
2018-09-26 20:50:38 +00:00
Fangrui Song 5dffc95b26 [ELF][test] Use llvm-readelf's short option -r instead of -relocations and remove ignored --wide
Reviewers: ruiu, sfertile, espindola

Reviewed By: ruiu

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

Differential Revision: https://reviews.llvm.org/D52124

llvm-svn: 343135
2018-09-26 19:48:07 +00:00
George Rimar 95aae4c59d [ELF] - Do not fail on R_*_NONE relocations when parsing the debug info.
This is https://bugs.llvm.org//show_bug.cgi?id=38919.

Currently, LLD may report "unsupported relocation target while parsing debug info"
when parsing the debug information.

At the same time LLD does that for zeroed R_X86_64_NONE relocations,
which obviously has "invalid" targets.

The nature of R_*_NONE relocation assumes them should be ignored.
This patch teaches LLD to stop reporting the debug information parsing errors for them.

Differential revision: https://reviews.llvm.org/D52408

llvm-svn: 343078
2018-09-26 08:11:34 +00:00
Martin Storsjo 32e651e169 [COFF] Don't do autoexport of symbols from GNU import libraries
This involves adding more generic list of symbol suffixes/prefixes
to ignore for autoexport; adding a few other entries to these lists
as well from the corresponding lists in binutils.

Differential Revision: https://reviews.llvm.org/D52382

llvm-svn: 343070
2018-09-26 06:13:47 +00:00
Martin Storsjo 2bfa125fd6 [COFF] Allow automatic dllimport from gnu import libraries
Don't assume that the IAT chunk will be a DefinedImportData, it can
just as well be a DefinedRegular for gnu import libraries.

Differential Revision: https://reviews.llvm.org/D52381

llvm-svn: 343069
2018-09-26 06:13:39 +00:00
Sam Clegg 4e62418b25 [WebAssembly] Add --export-default/--no-export-default options
These option control weather or not symbols marked as visibility
default are exported in the output binary.

By default this is true, but emscripten prefers to control the
exported symbol list explicitly at link time and ignore the
symbol attributes.

Differential Revision: https://reviews.llvm.org/D52003

llvm-svn: 343034
2018-09-25 21:50:15 +00:00
Rui Ueyama 378a028d91 Update a --help message and add -execute-only to the man page.
llvm-svn: 343032
2018-09-25 21:39:08 +00:00
Rui Ueyama 12ef7a9575 De-template VersionDefinitionSection. NFC.
When we write a struct to a mmap'ed buffer, we usually use
write16/32/64, but we didn't for VersionDefinitionSection, so
we needed to template that class.

llvm-svn: 343024
2018-09-25 20:37:51 +00:00
Rui Ueyama 4e247522ac Reset input section pointers to null on each linker invocation.
Previously, if you invoke lld's `main` more than once in the same process,
the second invocation could fail or produce a wrong result due to a stale
pointer values of the previous run.

Differential Revision: https://reviews.llvm.org/D52506

llvm-svn: 343009
2018-09-25 19:26:58 +00:00
Rui Ueyama ae34348354 Fix an error message. It must start with a lowercase letter.
llvm-svn: 342992
2018-09-25 17:12:50 +00:00
Rui Ueyama 7d053709d4 Parallelize .gdb_index string table writes.
When we are creating a large .gdb_index, this change makes a difference.

llvm-svn: 342978
2018-09-25 14:34:56 +00:00
Martin Storsjo 57ddec0dd1 [COFF] Add support for creating range extension thunks for ARM
This is a feature that MS link.exe lacks; it currently errors out on
such relocations, just like lld did before.

This allows linking clang.exe for ARM - practically, any image over
16 MB will likely run into the issue.

Differential Revision: https://reviews.llvm.org/D52156

llvm-svn: 342962
2018-09-25 10:59:29 +00:00
George Rimar b5a6538b07 [ELF] - Add -z global option to manual.
This was requested during review of D49374,
but for some unknown reason was not in the final commit.

llvm-svn: 342954
2018-09-25 09:32:31 +00:00
Yury Delendik d66aabc6d7 [WebAssembly] Move .debug_line section address of dead function outside section range
Summary:
Currently we are pointing all debug information that refer removed function code
to the beginning of the code section (offset = 0). A debugger may want to
resolve code offset to the debug information, which will collide with offsets
of the live functions.

Moving offsets of dead functions outside code section range.

Reviewers: sbc100

Reviewed By: sbc100

Subscribers: dblaikie, ruiu, alexcrichton, dschuff, aprantl, jgravelle-google, aheejin, sunfish, JDevlieghere, llvm-commits

Differential Revision: https://reviews.llvm.org/D49446

llvm-svn: 342930
2018-09-24 23:50:55 +00:00
Will Wilson 3cb18346d7 [lld-link] Generalize handling of /debug and /debug:{none,full,fastlink,ghash,symtab}
Implement final argument precedence if multiple /debug arguments are passed on the command-line to match expected link.exe behavior.
Support /debug:none and emit warning for /debug:fastlink with automatic fallback to /debug:full.
Emit error if last /debug:option is unknown.
Emit warning if last /debugtype:option is unknown.

https://reviews.llvm.org/D50404

llvm-svn: 342894
2018-09-24 15:28:03 +00:00
Ed Maste c8ec7a9e1e Correct RISC-V link in release notes
llvm-svn: 342887
2018-09-24 14:47:56 +00:00
Martin Storsjo 5f6d527f09 [COFF] Support linking to import libraries from GNU binutils
GNU binutils import libraries aren't the same kind of short import
libraries as link.exe and LLD produce, but are a plain static library
containing .idata section chunks. MSVC link.exe can successfully link
to them.

In order for imports from GNU import libraries to mix properly with the
normal import chunks, the chunks from the existing mechanism needs to
be added into named sections like .idata$2.

These GNU import libraries consist of one header object, a number of
object files, one for each imported function/variable, and one trailer.
Within the import libraries, the object files are ordered alphabetically
in this order. The chunks stemming from these libraries have to be
grouped by what library they originate from and sorted, to make sure
the section chunks for headers and trailers for the lists are ordered
as intended. This is done on all sections named .idata$*, before adding
the synthesized chunks to them.

Differential Revision: https://reviews.llvm.org/D38513

llvm-svn: 342777
2018-09-21 22:01:06 +00:00
Rui Ueyama c41985a50e Update release notes.
llvm-svn: 342754
2018-09-21 17:48:45 +00:00
Rui Ueyama a3d0f40964 Update release notes.
llvm-svn: 342748
2018-09-21 17:13:55 +00:00
Dimitry Andric c9de3b4d26 Align AArch64 and i386 image base to superpage
Summary:

As for x86_64, the default image base for AArch64 and i386 should be
aligned to a superpage appropriate for the architecture.

On AArch64, this is 2 MiB, on i386 it is 4 MiB.

Reviewers: emaste, grimar, javed.absar, espindola, ruiu, peter.smith, srhines, rprichard

Reviewed By: ruiu, peter.smith

Subscribers: jfb, markj, arichardson, krytarowski, kristof.beyls, llvm-commits

Differential Revision: https://reviews.llvm.org/D50297

llvm-svn: 342746
2018-09-21 16:58:13 +00:00