Commit Graph

2932 Commits

Author SHA1 Message Date
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
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
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
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
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
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 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
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
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
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
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
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 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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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 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
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
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
Fangrui Song 0178cff279 [ELF] --plugin-opt=thinlto-index-only: create empty index files even if all bitcode files are lazy
Summary:
The gold plugin behavior (creating empty index files for lazy bitcode
files) was added in D46034, but it missed the case when there is no
non-lazy bitcode files, e.g.

    ld.lld -shared crti.o crtbeginS.o --start-lib bitcode.o --end-lib ...

crti.o crtbeginS.o are not bitcode, but our distributed build system
wants bitcode.o.thinlto.bc to confirm all expected outputs are created
based on all of the modules provided to the linker.

Differential Revision: https://reviews.llvm.org/D61420

llvm-svn: 359788
2019-05-02 14:05:20 +00:00
Fangrui Song d8c2fa99c1 [ELF] Delete a cant-write test from test/lto/thinlto-index-only.ll
The test is performed by thinlto-cant-write-index.ll

llvm-svn: 359769
2019-05-02 09:29:24 +00:00
Fangrui Song c669ef1721 Delete trailing \r. NFC
llvm-svn: 359745
2019-05-02 00:39:03 +00:00
Ben Dunbobbin 6e32dd6cfd [LLD] Emit dynamic relocations for references to script symbols in -pie links
https://reviews.llvm.org/D55423 caused LLD to stop emitting dynamic relocations for references to script symbols in -pie links.

This patch fixes that regression.

https://reviews.llvm.org/D61298

llvm-svn: 359683
2019-05-01 14:07:31 +00:00
Fangrui Song 5387c2cd17 [llvm-objdump] Print newlines before and after "Disassembly of section ...:"
This improves readability and the behavior is consistent with GNU objdump.

The new test test/tools/llvm-objdump/X86/disassemble-section-name.s
checks we print newlines before and after "Disassembly of section ...:"

Differential Revision: https://reviews.llvm.org/D61127

llvm-svn: 359668
2019-05-01 10:40:48 +00:00
Fangrui Song 4672e52e22 [llvm-readobj] llvm-readobj --elf-output-style=GNU => llvm-readelf
While updating the test, change -l -S to -S -l as the output of -S goes
before -l.

llvm-svn: 359653
2019-05-01 06:02:16 +00:00
Fangrui Song b159906a9a [test] Change llvm-readobj -long-option to --long-option or well-known short options. NFC
Also change some options that have different semantics (cause confusion) in llvm-readelf mode:

-s => -S
-t => --symbols
-sd => --section-data

llvm-svn: 359651
2019-05-01 05:49:01 +00:00
Andrew Ng 24896d304d [LLD][ELF] /DISCARD/ output sections should not be orphans
/DISCARD/ output sections were being treated as orphans. As a result, if
a /DISCARD/ output section has been assigned a PHDR, it could cause
incorrect assignment of sections to segments.

Differential Revision: https://reviews.llvm.org/D61186

llvm-svn: 359565
2019-04-30 14:31:22 +00:00
Andrew Ng 0f4c58f6f4 [LLD][ELF] Fix getRankProximity to "ignore" not live sections
This is a follow up to r358979 which made findOrphanPos only consider
live sections. Unfortunately, this required change to getRankProximity,
used by findOrphanPos, was missed.

Differential Revision: https://reviews.llvm.org/D61197

llvm-svn: 359554
2019-04-30 12:27:06 +00:00
George Rimar dee900ae59 [LLD][ELF] - Do not remove empty sections referenced in LOADADDR/ADDR commands.
This is https://bugs.llvm.org//show_bug.cgi?id=38750.

If script references empty sections in LOADADDR/ADDR commands

.empty  : { *(.empty ) }
.text   : AT(LOADADDR (.empty) + SIZEOF (.empty)) { *(.text) }
then an empty section will be removed and LOADADDR/ADDR will evaluate to null.
It is not that user may expect from using of the generic script, what is a common case.

Differential revision: https://reviews.llvm.org/D54621

llvm-svn: 359279
2019-04-26 06:59:30 +00:00
George Rimar 44f2d74aa5 [LLD][ELF] - Convert symbol-index.s testcase to a YAML test case. NFCI.
This removes one more binary object from the inputs and fixes the
test case description.

Previously it said that:
"symbol-index.elf has incorrect type of .symtab section.
There is no symbol bodies because of that and any symbol index becomes incorrect."

But the real reason of the failture was not the incorrect type of a symbol table,
but invalid index of the symbol used in a relocation, what happened because
previous test tried to read .symtab as a SHT_RELA section.

llvm-svn: 359197
2019-04-25 15:08:52 +00:00
George Rimar e043417268 [LLD][ELF] - Move the test to a correct folder, remove excessive input. NFCI.
This test should live in `invalid` folder.

Also it was possible to avoid adding input
with use of `-docnum=x` yaml2obj argument.

llvm-svn: 359194
2019-04-25 14:53:23 +00:00
Fangrui Song 513d3658e7 [PPC64] Consider localentry offset when computing branch distance
Summary:
We don't take localentry offset into account, and thus may fail to
create a long branch when the gap is just a few bytes smaller than 2^25.

relocation R_PPC64_REL24 out of range: 33554432 is not in [-33554432, 33554431]
relocation R_PPC64_REL24 out of range: 33554436 is not in [-33554432, 33554431]

Fix that by adding the offset to the symbol VA.

Differential Revision: https://reviews.llvm.org/D61058

llvm-svn: 359094
2019-04-24 14:03:30 +00:00
George Rimar fa34952a00 [LLD][ELF] - Remove binding.elf binary from test case. NFCI.
This introduces YAML based invalid-binding.test instead.

llvm-svn: 359086
2019-04-24 12:16:39 +00:00
George Rimar 1ee7bee224 [LLD][ELD] - Remove excessive lines from test. NFC.
They are not used.

llvm-svn: 359084
2019-04-24 12:00:09 +00:00
George Rimar bb2079b7e1 [LLD][ELF] - Remove dynamic-section-sh_size.elf binary, convert test to yaml. NFCI.
dynamic-section-sh_size.elf was introduced in D25090.
Now it is possible to use yaml2obj instead. 
That is what this patch does.

Also I added one more case of a possibly broken .dynamic
section just in case.

llvm-svn: 358990
2019-04-23 14:21:31 +00:00
George Rimar 95203efc1a [LLD][ELF] - Remove file-class.a binary from inputs and improve the test case.
file-class.a was used to diagnose the "corrupted ELF file: invalid file class"
error when the object was fetched from the archive.

file-class.a contained an object of 16 bytes size. I replaced it with
an echo call (because it is impossible to use yaml2obj for that, and I am
not sure it is worth to support), and also increased its size to 18 bytes.
That allowed to also test a case when such object is a regular input and not an
archive member (we have a bit different logic for these cases).

llvm-svn: 358985
2019-04-23 13:27:54 +00:00
Andrew Ng ccba42c7eb [ELF] Change default output section type to SHT_PROGBITS
This fixes an issue where a symbol only section at the start of a
PT_LOAD segment, causes incorrect alignment of the file offset for the
start of the segment which results in the output of an invalid ELF.

SHT_PROGBITS was the default output section type in the past.

Differential Revision: https://reviews.llvm.org/D60131

llvm-svn: 358981
2019-04-23 12:38:52 +00:00
Fangrui Song 003c18a39c [PPC][PPC64] Improve some llvm-objdump -d -D tests
Various improvement:

Some offsets in disassembly are incorrect after several layout adjustment. Fix them.
llvm-objdump -D should not be used. -D dumps unrelated non-text sections. Replace them with llvm-objdump -d, llvm-readelf -x, etc
Many llvm-objdump -d tests use {{.*}} . Add the option --no-show-raw-insn to avoid check hex bytes.

ppc64-long-branch.s does not need a shared object. Delete it.
Make ppc64-ifunc.s check 2 ifuncs.

Reviewers: ruiu, espindola

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60998

llvm-svn: 358975
2019-04-23 11:47:28 +00:00
George Rimar 6684a351ed [LLD][ELF] - Fix mips-invalid-options-descriptor.s test case and convert to YAML.
It was initially introduced in D25229 to report the "zero option descriptor size"
error message. In following commits it was broken and did not report this
error anymore. I think that happened because elf object was a result of fuzzing
and it was broken in many ways.

This patch converts this test to a YAML, removes a binary and hence fixes the
original intention.

llvm-svn: 358972
2019-04-23 11:19:51 +00:00
George Rimar b7dc13f4c0 [LLD][ELF] - Remove multiple-eh-relocs.elf binary from the inputs. NFCI.
Introduced multiple-relocations-sections.test based on YAML instead.

llvm-svn: 358966
2019-04-23 10:03:09 +00:00
George Rimar 545f621a7c [LLD][ELF] - Update test case after llvm-mc change.
rL358960 "[llvm-mc] - Properly set the the address align field of the compressed sections."
changed the sh_addralign field of the "zlib" compressed debug sections.

llvm-svn: 358961
2019-04-23 09:30:26 +00:00
Fangrui Song d986e41fe4 [PPC64] Allow R_PPC64_DTPREL* to preemptable local-dynamic symbols
Similar to D60945.

Differential Revision: https://reviews.llvm.org/D60994

llvm-svn: 358950
2019-04-23 06:31:44 +00:00
George Rimar 81ffc08a8a [LLD][ELF] - Remove a binary from the inputs. NFCI.
section-index.elf was removed and the corresponding test
was replaced with a yaml2obj based test.

llvm-svn: 358889
2019-04-22 14:53:32 +00:00
George Rimar 3275742898 [LLD][ELF] - Do not forget to use ch_addralign field after decompressing the sections.
LLD did not use ELF::Chdr::ch_addralign for decompressed sections.
This resulted in a broken output.

Fixes https://bugs.llvm.org/show_bug.cgi?id=40482.

Differential revision: https://reviews.llvm.org/D60959

llvm-svn: 358885
2019-04-22 13:40:42 +00:00
George Rimar f902250fc1 [LLD][ELF] - Handle quoted strings in the linker scripts correctly.
This is the https://bugs.llvm.org/show_bug.cgi?id=41356,

Seems it is kind of unusual case but it is possible to
have sections that require quotes for their namings.
Like "aaa bbb".

This patch adds support for those.

Differential revision: https://reviews.llvm.org/D60901

llvm-svn: 358874
2019-04-22 07:57:07 +00:00
Fangrui Song bc4b159bb1 [ELF][X86] Allow R_386_TLS_LDO_32 and R_X86_64_DTPOFF{32,64} to preemptable local-dynamic symbols
Summary:
Fixes PR35242. A simplified reproduce:

    thread_local int i; int f() { return i; }

% {g++,clang++} -fPIC -shared -ftls-model=local-dynamic -fuse-ld=lld a.cc
ld.lld: error: can't create dynamic relocation R_X86_64_DTPOFF32 against symbol: i in readonly segment; recompile object files with -fPIC or pass '-Wl,-z,notext' to allow text relocations in the output

In isStaticLinkTimeConstant(), Syn.IsPreemptible is true, so it is not
seen as a constant. The error is then issued in processRelocAux().

A symbol of the local-dynamic TLS model cannot be preempted but it can
preempt symbols of the global-dynamic TLS model in other DSOs.
So it makes some sense that the variable is not static.

This patch fixes the linking error by changing getRelExpr() on
R_386_TLS_LDO_32 and R_X86_64_DTPOFF{32,64} from R_ABS to R_DTPREL.
R_PPC64_DTPREL_* and R_MIPS_TLS_DTPREL_* need similar fixes, but they are not handled in this patch.

As a bonus, we use `if (Expr == R_ABS && !Config->Shared)` to find
ld-to-le opportunities. R_ABS is overloaded here for such STT_TLS symbols.
A dedicated R_DTPREL is clearer.

Differential Revision: https://reviews.llvm.org/D60945

llvm-svn: 358870
2019-04-22 03:10:40 +00:00
George Rimar 5f7665969a [LLD][ELF] - Fix mistype. NFC.
Change the tripple name from
aarch64-linux-gnux to -triple=aarch64-linux-gnu

llvm-svn: 358810
2019-04-20 10:50:27 +00:00
Ali Tamur 783d84bb39 [llvm] Prevent duplicate files in debug line header in dwarf 5: another attempt
Another attempt to land the changes in debug line header to prevent duplicate
files in Dwarf 5. I rolled back my previous commit because of a mistake in
generating the object file in a test. Meanwhile, I addressed some offline
comments and changed the implementation; the largest difference is that
MCDwarfLineTableHeader does not keep DwarfVersion but gets it as a parameter. I
also merged the patch to fix two lld tests that will strt to fail into this
patch.

Original Commit:

https://reviews.llvm.org/D59515

Original Message:
Motivation: In previous dwarf versions, file name indexes started from 1, and
the primary source file was not explicit. Dwarf 5 standard (6.2.4) prescribes
the primary source file to be explicitly given an entry with an index number 0.

The current implementation honors the specification by just duplicating the
main source file, once with index number 0, and later maybe with another
index number. While this is compliant with the letter of the standard, the
duplication causes problems for consumers of this information such as lldb.
(Some files are duplicated, where only some of them have a line table although
all refer to the same file)

With this change, dwarf 5 debug line section files always start from 0, and
the zeroth entry is not duplicated whenever possible. This requires different
handling of dwarf 4 and dwarf 5 during generation (e.g. when a function returns
an index zero for a file name, it signals an error in dwarf 4, but not in dwarf
5) However, I think the minor complication is worth it, because it enables all
consumers (lldb, gdb, dwarfdump, objdump, and so on) to treat all files in the
file name list homogenously.

llvm-svn: 358732
2019-04-19 02:26:56 +00:00
George Rimar 55e1987f81 [LLD][ELF] - Convert out-of-order-section-in-region.s to *.test. NFCI.
This is consistent with the our others tests that has large scripts.

llvm-svn: 358659
2019-04-18 12:13:41 +00:00
George Rimar 69186f82f3 [LLD][ELF] - A fix for "linker script assignment loses relative nature of section" bug.
This is https://bugs.llvm.org//show_bug.cgi?id=39857.
I added the comment with much more details to the bug page,
the short version is below.

The following script and code demonstrates the issue:

aliasto__text = __text;
 SECTIONS {
  .text 0x1000 : { __text = . ; *(.text) }
 }
...
call aliasto__text

LLD fails with "cannot refer to absolute symbol: aliasto__text" error.
It happens because at the moment of scanning the relocations
we do not yet assign the correct/final/any section value for the symbol aliasto__text.
I made a change to Relocations.cpp to fix that.

Also, I had to remove the symbol-location.s test case completely, because now it does not
trigger any error. Since now all linker scripts symbols are resolved to constants, no
errors can be triggered at all it seems. I checked that it is consistent with the behavior
of bfd and gold (they do not trigger errors for the case from symbol-location.s), so it should
be OK. I.e. at least it is probably not the best possible, but natural behavior we obtained.

Differential revision: https://reviews.llvm.org/D55423

llvm-svn: 358652
2019-04-18 10:00:37 +00:00
Fangrui Song 3deff86657 [ELF] Respect NonAlloc when copying flags from the previous sections
Summary:
If the output section contains only symbol assignments, we copy flags
from the previous sections. Don't set SHF_ALLOC if NonAlloc is true.

We also have to change the type from SHT_NOBITS to SHT_PROGBITS.
In ld.bfd, bfd_elf_get_default_section_type maps non-alloctable sections to SHT_PROGBITS.
Non-alloctable SHT_NOBITS sections do not make sense.

Fixes PR38626

Differential Revision: https://reviews.llvm.org/D59986

llvm-svn: 358650
2019-04-18 09:22:05 +00:00
George Rimar da49faf15e [LLD][ELF] - Fix the different behavior of the linker script symbols on different platforms.
This generalizes code and also fixes the broken behavior shown in
one of our test cases for some targets, like x86-64.

The issue occurs when the forward declarations are used in the script.
One of the samples is:

SECTIONS {
  foo = ADDR(.text) - ABSOLUTE(ADDR(.text));
};

In that case, we have a broken output when output target does
not use thunks. That happens because thunks creating code
(called from maybeAddThunks)
calls Script->assignAddresses() at least one more time,
what fixups the values. As a result final symbols values can
be different on AArch64 and x86, for example.

In this patch, I generalize and rename maybeAddThunks to
finalizeAddressDependentContent and now it is used and called
by all targets.

Differential revision: https://reviews.llvm.org/D55550

llvm-svn: 358646
2019-04-18 08:15:54 +00:00
Rui Ueyama 14ef9b30b6 lld: elf: Fix sections with explict addresses in regions
Patch by Gabriel Smith.

The address for a section would be evaluated before the region was
switched to. Because of this, the position within the region would not
be updated. After the region is swapped to the dot would be set to the
out of date position within the region, undoing the section address
evaluation.

To fix this, the region is swapped to before the section's address is
evaluated. As part of the fallout of this, expandMemoryRegions needed
to be gated in setDot on the condition that the evaluated address is
less than the dot. This is for the case where sections are not listed
from lowest address to highest address.

Finally, a test for the case where sections are listed "out of order"
was added.

Differential Revision: https://reviews.llvm.org/D60744

llvm-svn: 358638
2019-04-18 02:32:12 +00:00
Fangrui Song abc068fc59 [ELF] Fix typo: .symtab_shndxr -> .symtab_shndx
The typo was introduced to llvm MC in rL204769 (fixed in rL358247) and then to lld.

Also, for relocatable-many-sections.s, the size of .symtab changed at some point and the formula needs update.

llvm-svn: 358248
2019-04-12 02:20:52 +00:00
Xing GUO 8ab7414580 [llvm-readobj] Should declare `ListScope` for `verneed` entries.
Summary: YAML mappings require keys to be unique. See: https://yaml.org/spec/1.2/spec.html#id2764652

Reviewers: jhenderson, grimar, rupprecht, espindola, ruiu

Reviewed By: ruiu

Subscribers: ruiu, emaste, arichardson, MaskRay, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60438

llvm-svn: 358078
2019-04-10 12:47:21 +00:00
Rui Ueyama 3a8bb7cd2c Discard debuginfo for object files empty after GC
Patch by Robert O'Callahan.

Rust projects tend to link in all object files from all dependent
libraries and rely on --gc-sections to strip unused code and data.
Unfortunately --gc-sections doesn't currently strip any debuginfo
associated with GC'ed sections, so lld links in the full debuginfo from
all dependencies even if almost all that code has been discarded. See
https://github.com/rust-lang/rust/issues/56068 for some details.

Properly stripping debuginfo for discarded sections would be difficult,
but a simple approach that helps significantly is to mark debuginfo
sections as live only if their associated object file has at least one
live code/data section. This patch does that. In a (contrived but not
totally artificial) Rust testcase linked above, it reduces the final
binary size from 46MB to 5.1MB.

Differential Revision: https://reviews.llvm.org/D54747

llvm-svn: 358069
2019-04-10 10:37:10 +00:00
Chih-Mao Chen 23e23836d5 Move tests in r357996 to correct location within monorepo
llvm-svn: 357997
2019-04-09 11:46:47 +00:00
Chih-Mao Chen 00100b5d0d [RISCV] Rewrite tests to use llvm-mc/llvm-objdump
Previously the tests in lld for RISC-V were given in yaml format as
LLVM's RISC-V assembler support was incomplete. Now that the
assembler/disassembler has matured we can rewrite all tests to use
LLVM's tools.

Differential Revision: https://reviews.llvm.org/D60415

llvm-svn: 357996
2019-04-09 11:39:50 +00:00
Peter Collingbourne d3e207057f ELF: Move verneed tracking data structures out of VersionNeedSection.
For partitions I intend to use the same set of version indexes in
each partition for simplicity. Since each partition will need its own
VersionNeedSection this will require moving the verneed tracking out of
VersionNeedSection. The way I've done this is to move most of the tracking
into SharedFile. What will eventually become the per-partition tracking
still lives in VersionNeedSection.

As a bonus the code gets a little simpler and more consistent with how we
handle verdef.

Differential Revision: https://reviews.llvm.org/D60307

llvm-svn: 357926
2019-04-08 17:48:05 +00:00
Rui Ueyama 4af8d47d05 Fix -emit-reloc against local symbols.
Previously, we drop symbols starting with .L from the symbol table, so
if there is a relocation that refers a .L symbol, it ended up
referencing a null -- which happened to be interpreted as an absolute
symbol.

This patch copies all symbols including local ones if -emit-reloc is
given.

Fixes https://bugs.llvm.org/show_bug.cgi?id=41385

Differential Revision: https://reviews.llvm.org/D60306

llvm-svn: 357885
2019-04-08 06:45:07 +00:00
George Rimar ff3397247f [LLD] - Update the test cases after yaml2obj change.
https://reviews.llvm.org/D60122 (r357595) changed the
symbols description format.

This change updates the LLD tests.

llvm-svn: 357596
2019-04-03 14:54:22 +00:00
Rumeet Dhindsa 45bd9b2567 Fixed the lld test using ld-lld command to use ld.lld instead.
Differential Revision: https://reviews.llvm.org/D59962

llvm-svn: 357216
2019-03-28 22:14:46 +00:00
Peter Smith 3ce9af9370 [ELF][ARM] Recommit Redesign of .ARM.exidx handling to use a SyntheticSection
Recommit r356666 with fixes for buildbot failure, as well as handling for
--emit-relocs, which we decide not to emit any relocation sections as the
table is already position independent and an offline tool can deduce the
relocations.

Instead of creating extra Synthetic .ARM.exidx sections to account for
gaps in the table, create a single .ARM.exidx SyntheticSection that can
derive the contents of the gaps from a sorted list of the executable
InputSections. This has the benefit of moving the ARM specific code for
SyntheticSections in SHF_LINK_ORDER processing and the table merging code
into the ARM specific SyntheticSection. This also makes it easier to create
EXIDX_CANTUNWIND table entries for executable InputSections that don't
have an associated .ARM.exidx section.

Fixes pr40277

Differential Revision: https://reviews.llvm.org/D59216

llvm-svn: 357160
2019-03-28 11:10:20 +00:00
Rui Ueyama 432030e843 [ELF] Dump symbols ordered by profiled guided section layout to file.
Patch by Tiancong Wang.

In D36351, Call-Chain Clustering (C3) heuristic is implemented with
option --call-graph-ordering-file <file>.
This patch adds a flag --print-symbol-order=<file> to LLD, and when
specified, it prints out the symbols ordered by the heuristics to the
file. The symbols printout is helpful to those who want to understand
the heuristics and want to reproduce the ordering with
--symbol-ordering-file in later pass.

Differential Revision: https://reviews.llvm.org/D59311

llvm-svn: 357133
2019-03-27 23:52:22 +00:00
Andrew Ng e6b6ab2c66 [LLD] Restore tests that use "-" as output
No longer require workarounds for output to "-" (stdout) for
Windows. These workarounds were just hiding the actual problem which has
been fixed in r357058.

Differential Revision: https://reviews.llvm.org/D59824

llvm-svn: 357072
2019-03-27 15:30:52 +00:00
Ali Tamur cea9548028 Revert "[lld] Reapply "Prevent duplicate files in debug line header in dwarf 5.""
This reverts commit rL357020

Reason: rL357018, which this commit depend on breaks the test:
llvm/test/tools/llvm-objdump/embedded-source.test on some architectures.

llvm-svn: 357025
2019-03-26 19:57:13 +00:00
Ali Tamur 5c2f176ccc [lld] Reapply "Prevent duplicate files in debug line header in dwarf 5."
Reapply rL356943; the previous attempt was reverted because the patch rL356941
that this depended on had broken a test.

Original commit message:

[lld] Prevent duplicate files in debug line header in dwarf 5.

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59671

llvm-svn: 357020
2019-03-26 18:59:52 +00:00
Fangrui Song 210949a221 [ELF] Change GOT*_FROM_END (relative to end(.got)) to GOTPLT* (start(.got.plt))
Summary:
This should address remaining issues discussed in PR36555.

Currently R_GOT*_FROM_END are exclusively used by x86 and x86_64 to
express relocations types relative to the GOT base. We have
_GLOBAL_OFFSET_TABLE_ (GOT base) = start(.got.plt) but end(.got) !=
start(.got.plt)

This can have problems when _GLOBAL_OFFSET_TABLE_ is used as a symbol, e.g.
glibc dl_machine_dynamic assumes _GLOBAL_OFFSET_TABLE_ is start(.got.plt),
which is not true.

  extern const ElfW(Addr) _GLOBAL_OFFSET_TABLE_[] attribute_hidden;
  return _GLOBAL_OFFSET_TABLE_[0]; // R_X86_64_GOTPC32

In this patch, we

* Change all GOT*_FROM_END to GOTPLT* to fix the problem.
* Add HasGotPltOffRel to denote whether .got.plt should be kept even if
  the section is empty.
* Simplify GotSection::empty and GotPltSection::empty by setting
  HasGotOffRel and HasGotPltOffRel according to GlobalOffsetTable early.

The change of R_386_GOTPC makes X86::writePltHeader simpler as we don't
have to compute the offset start(.got.plt) - Ebx (it is constant 0).

We still diverge from ld.bfd (at least in most cases) and gold in that
.got.plt and .got are not adjacent, but the advantage doing that is
unclear.

Reviewers: ruiu, sivachandra, espindola

Subscribers: emaste, mehdi_amini, arichardson, dexonsmith, jdoerfert, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59594

llvm-svn: 356968
2019-03-25 23:46:19 +00:00
Ali Tamur 800fe977d0 Revert "[lld] Prevent duplicate files in debug line header in dwarf 5."
This reverts commit 5aa7478a55.

Some things are broken; I will fix and try to commit again.

llvm-svn: 356949
2019-03-25 21:06:02 +00:00
Ali Tamur 5aa7478a55 [lld] Prevent duplicate files in debug line header in dwarf 5.
Summary:
Changes to a couple of tests that will start failing after https://reviews.llvm.org/D59515 is submitted.

Reviewers: echristo, ruiu, espindola

Reviewed By: echristo, ruiu

Subscribers: emaste, arichardson, MaskRay, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59671

llvm-svn: 356943
2019-03-25 20:18:27 +00:00
Peter Smith 54dab70bb7 [ELF][ARM] Revert Redesign of .ARM.exidx handling to use a SyntheticSection
There is a reproducible buildbot failure (segfault) on the 2 stage
clang-cmake-armv8-lld bot. Reverting while I investigate.

Differential Revision: https://reviews.llvm.org/D59216

llvm-svn: 356684
2019-03-21 17:17:54 +00:00
Peter Smith d3511a214e [ELF][ARM] Redesign of .ARM.exidx handling to use a SyntheticSection
Instead of creating extra Synthetic .ARM.exidx sections to account for
gaps in the table, create a single .ARM.exidx SyntheticSection that can
derive the contents of the gaps from a sorted list of the executable
InputSections. This has the benefit of moving the ARM specific code for
SyntheticSections in SHF_LINK_ORDER processing and the table merging code
into the ARM specific SyntheticSection. This also makes it easier to create
EXIDX_CANTUNWIND table entries for executable InputSections that don't
have an associated .ARM.exidx section.

Fixes pr40277

Differential Revision: https://reviews.llvm.org/D59216

llvm-svn: 356666
2019-03-21 14:06:40 +00:00
Robert Lougher 364cb6b5d7 [TailCallElim] Update tests for LTO pipeline change
D58391 changed the LTO pipelines to add the tailcall elimination pass.
This caused three LLD tests to fail.

Differential Revision: https://reviews.llvm.org/D59604

llvm-svn: 356593
2019-03-20 19:05:05 +00:00
Fangrui Song 1092fc9057 [ELF] Allow sh_entsize to be unrelated to sh_addralign and not a power of 2
Summary:
This implements Rui Ueyama's idea in PR39044.
I've checked that ld.bfd and gold do not have the power-of-2 requirement
and do not require sh_entsize to be a multiple of sh_align.

Now on the updated test merge-entsize.s, all the 3 linkers happily
create .rodata that is not 3-byte aligned.

This has a use case in Linux arch/x86/crypto/sha512-avx2-asm.S
It uses sh_entsize of 640, which is not a power of 2.
See https://github.com/ClangBuiltLinux/linux/issues/417

Reviewers: ruiu, espindola

Reviewed By: ruiu

Subscribers: nickdesaulniers, E5ten, emaste, arichardson, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59478

llvm-svn: 356428
2019-03-18 23:49:18 +00:00
Siva Chandra 1915e2be93 [ELF] Emit weak-undef symbols in .dynsym of a PIE binary only if linked against shared libs.
Reviewers: espindola

Subscribers: emaste, arichardson, MaskRay, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59275

llvm-svn: 356374
2019-03-18 15:32:57 +00:00
George Rimar 738146ab33 [LLD][ELF] - Replace one of the tests with a YAML version.
This removes one more binary from the inputs.

Differential revision: https://reviews.llvm.org/D59085

llvm-svn: 356334
2019-03-17 15:46:03 +00:00
Fangrui Song 639058d7c9 [ELF] Add a test for large .bss.rel.ro
Reviewers: ruiu, pcc, espindola

Reviewed By: pcc

Subscribers: emaste, arichardson, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59404

llvm-svn: 356230
2019-03-15 03:37:42 +00:00
Fangrui Song f4646a0bb1 [ELF] Fix 3 tests after D56828
arm-plt-reloc.s arm-thumb-plt-reloc.s: update offset calculations

pack-dyn-relocs-loop.s: this test is very sensitive to exact section
offsets and sizes. If we comment out the following two lines in
SyntheticSections.cpp, we should reproduce `ld.lld: error: thunk
creation not converged` caused by oscillation of the section size.

  if (RelocData.size() < OldSize)
    RelocData.append(OldSize - RelocData.size(), 0);

Use -z norelro to counteract the layout change (to be more specific,
we have to place .dynamic below .foo so that offset(foo) remains 0x10004)

llvm-svn: 356229
2019-03-15 03:20:13 +00:00
Fangrui Song e8710ef1fb [ELF] Split RW PT_LOAD on the PT_GNU_RELRO boundary
Summary:
Based on Peter Collingbourne's suggestion in D56828.

Before D56828: PT_LOAD(.data PT_GNU_RELRO(.data.rel.ro .bss.rel.ro) .bss)
Old:           PT_LOAD(PT_GNU_RELRO(.data.rel.ro .bss.rel.ro) .data .bss)
New:           PT_LOAD(PT_GNU_RELRO(.data.rel.ro .bss.rel.ro)) PT_LOAD(.data. .bss)

The new layout reflects the runtime memory mappings.
By having two PT_LOAD segments, we can utilize the NOBITS part of the
first PT_LOAD and save bytes for .bss.rel.ro.

.bss.rel.ro is currently small and only used by copy relocations of
symbols in read-only segments, but it can be used for other purposes in
the future, e.g. if a relro section's statically relocated data is all
zeros, we can move it to .bss.rel.ro.

Reviewers: espindola, ruiu, pcc

Reviewed By: ruiu

Subscribers: nemanjai, jvesely, nhaehnle, javed.absar, kbarton, emaste, arichardson, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D58892

llvm-svn: 356226
2019-03-15 01:29:57 +00:00
Rui Ueyama cc8e4e839f Make a hack for LTO work only when you are actually doing LTO.
We allow an archive file without symbol table as a linker input as a
workaround for a very common error in LTO build. But that logic worked
even for an archive file containing non-bitcode files, which is not
expected. This patch limits that workaround to one that contains only
bitcode files.

Differential Revision: https://reviews.llvm.org/D59373

llvm-svn: 356186
2019-03-14 18:21:32 +00:00
Fangrui Song 07f8daf05e [ELF] Simplify RelRo, TLS, NOBITS section ranks and make RW PT_LOAD start with RelRo
Old: PT_LOAD(.data | PT_GNU_RELRO(.data.rel.ro .bss.rel.ro) | .bss)
New: PT_LOAD(PT_GNU_RELRO(.data.rel.ro .bss.rel.ro) | .data .bss)

The placement of | indicates page alignment caused by PT_GNU_RELRO. The
new layout has simpler rules and saves space for many cases.

Old size: roundup(.data) + roundup(.data.rel.ro)
New size: roundup(.data.rel.ro + .bss.rel.ro) + .data

Other advantages:

* At runtime the 3 memory mappings decrease to 2.
* start(PT_TLS) = start(PT_GNU_RELRO) = start(RW PT_LOAD). This
  simplifies binary manipulation tools.
  GNU strip before 2.31 discards PT_GNU_RELRO if its
  address is not equal to the start of its associated PT_LOAD.
  This has been fixed by https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=f2731e0c374e5323ce4cdae2bcc7b7fe22da1a6f
  But with this change, we will be compatible with GNU strip before 2.31
* Before, .got.plt (non-relro by default) was placed before .got (relro
  by default), which made it impossible to have _GLOBAL_OFFSET_TABLE_
  (start of .got.plt on x86-64) equal to the end of .got (R_GOT*_FROM_END)
  (https://bugs.llvm.org/show_bug.cgi?id=36555). With the new ordering, we
  can improve on this regard if we'd like to.

Reviewers: ruiu, espindola, pcc

Subscribers: emaste, arichardson, llvm-commits, joerg, jdoerfert

Differential Revision: https://reviews.llvm.org/D56828

llvm-svn: 356117
2019-03-14 03:47:45 +00:00
Francis Visoiu Mistrih dd42236c6c Reland "[Remarks] Add -foptimization-record-passes to filter remark emission"
Currently we have -Rpass for filtering the remarks that are displayed as
diagnostics, but when using -fsave-optimization-record, there is no way
to filter the remarks while generating them.

This adds support for filtering remarks by passes using a regex.
Ex: `clang -fsave-optimization-record -foptimization-record-passes=inline`

will only emit the remarks coming from the pass `inline`.

This adds:

* `-fsave-optimization-record` to the driver
* `-opt-record-passes` to cc1
* `-lto-pass-remarks-filter` to the LTOCodeGenerator
* `--opt-remarks-passes` to lld
* `-pass-remarks-filter` to llc, opt, llvm-lto, llvm-lto2
* `-opt-remarks-passes` to gold-plugin

Differential Revision: https://reviews.llvm.org/D59268

Original llvm-svn: 355964

llvm-svn: 355984
2019-03-12 21:22:27 +00:00
Peter Collingbourne 8a28673a2e ELF: Don't add .dynamic strings to .dynstr early.
This does not appear to be necessary because StringTableSection does not
need to be finalized, which also means that we can remove the call to
finalizeSynthetic on .dynstr.

Differential Revision: https://reviews.llvm.org/D59240

llvm-svn: 355977
2019-03-12 20:58:34 +00:00
Francis Visoiu Mistrih 1d6c47ad2b Revert "[Remarks] Add -foptimization-record-passes to filter remark emission"
This reverts commit 20fff32b7d.

llvm-svn: 355976
2019-03-12 20:54:18 +00:00
Francis Visoiu Mistrih 20fff32b7d [Remarks] Add -foptimization-record-passes to filter remark emission
Currently we have -Rpass for filtering the remarks that are displayed as
diagnostics, but when using -fsave-optimization-record, there is no way
to filter the remarks while generating them.

This adds support for filtering remarks by passes using a regex.
Ex: `clang -fsave-optimization-record -foptimization-record-passes=inline`

will only emit the remarks coming from the pass `inline`.

This adds:

* `-fsave-optimization-record` to the driver
* `-opt-record-passes` to cc1
* `-lto-pass-remarks-filter` to the LTOCodeGenerator
* `--opt-remarks-passes` to lld
* `-pass-remarks-filter` to llc, opt, llvm-lto, llvm-lto2
* `-opt-remarks-passes` to gold-plugin

Differential Revision: https://reviews.llvm.org/D59268

llvm-svn: 355964
2019-03-12 20:28:50 +00:00
Xing GUO 08dc382465 fix break tests after rL355922. NFCI
llvm-svn: 355925
2019-03-12 14:58:01 +00:00
George Rimar 43b6689e64 [LLD][ELF] - Show symbols visibility in "undefined symbol..." error messages.
This teaches LLD to report visibility when showing undefined symbol errors
and fixes https://bugs.llvm.org/show_bug.cgi?id=40770.

Differential revision: https://reviews.llvm.org/D58577

llvm-svn: 355909
2019-03-12 11:10:29 +00:00
Eli Friedman 5b1027a908 Fix test to unconditionally create a GNU-format archive.
On Darwin targets, llvm-ar creates a Darwin format archive by default,
which ld.lld can't read, so it was printing an unexpected error.

llvm-svn: 355894
2019-03-12 02:20:01 +00:00
Eli Friedman 3751ae4a94 [ELF] Print a better error for an archive containing a non-ELF file.
Hopefully gives a more readable error message for the most obvious
mistake.

Differential Revision: https://reviews.llvm.org/D59170

llvm-svn: 355888
2019-03-12 01:24:39 +00:00
Rui Ueyama 033c4d2126 Include an archive file name in an error message for a corrupted file.
Differential Revision: https://reviews.llvm.org/D59212

llvm-svn: 355886
2019-03-12 00:24:34 +00:00
Mitch Phillips 88bea2b49b [LLD] Fixed flaky unit test based on build directory.
This unit test fails if 'zed' appears in your build path, as lld is
echoing out the path of the source file. Change the unit test to
explicitly only match everything after the 'Symbols [' line of the
output, to make sure that this test doesn't inadvertently fail due to
the build path.

llvm-svn: 355748
2019-03-08 22:33:22 +00:00
Petar Jovanovic c8955e2293 fix expected format in test/ELF/eh-frame-hdr-augmentation.s
Follow-up for r355605.
Fix expected format in test/ELF/eh-frame-hdr-augmentation.s

llvm-svn: 355621
2019-03-07 18:28:44 +00:00
Sam Clegg 815a05ca6b [WebAssembly] LTO: Don't include bitcode-only symbols in the symtab
Fixes https://bugs.llvm.org/show_bug.cgi?id=40654

Differential Revision: https://reviews.llvm.org/D59012

llvm-svn: 355577
2019-03-07 02:43:19 +00:00
George Rimar a033572d67 [LLD][ELF] - Convert common-symbol-alignment.s test to yaml.
This removes 2 precompiled binaries from the inputs.

llvm-svn: 355500
2019-03-06 13:49:41 +00:00
George Rimar d024a9fab3 [LLD][ELF] - Remove unused invalid input object. NFC.
It was introduced by me in 2016: r290335,
but the test did contain the YAML from start,
I think it was committed by mistake.

llvm-svn: 355497
2019-03-06 12:37:46 +00:00
Fangrui Song 5eaa55f616 [ELF][test] chmod u+w to prevent annoying rm prompt
If the permission does not permit writing and the standard input is a
terminal, rm gives an annoying prompt. chmod u+w to make the output
directory easier to delete.

llvm-svn: 355382
2019-03-05 09:56:50 +00:00
Alexey Lapshin ded118079b [LLD] add test for line number info related to differrent .text sections
There is a bug for llvm-objdump which incorrectly reported line number
   info for object file if several .text sections presented.
   https://bugs.llvm.org/show_bug.cgi?id=40703 .
   This patch adds test for the same situation.

   Differential revision: https://reviews.llvm.org/D58357

llvm-svn: 355306
2019-03-04 10:42:54 +00:00
Peter Collingbourne 16d9a0acfd ELF: Change FileSize back to a uint64_t.
This lets us detect file size overflows when creating a 64-bit binary on
a 32-bit machine.

Differential Revision: https://reviews.llvm.org/D58840

llvm-svn: 355218
2019-03-01 18:53:41 +00:00
Matt Davis b95daf0b77 [lld][test] Fix tests. llvm-readobj now emits symbol section names.
This is the result of patch 99e9c4cad08164b9c0ca565ab9ad48ce132e98e5
See the related patch https://reviews.llvm.org/D58796

llvm-svn: 355211
2019-03-01 18:01:41 +00:00
George Rimar aee005291c [LLD][ELF] - Convert 3 testcases to use yaml instead of binaries.
This change makes 3 tests to use yaml instead of binaries.

Differential revision: https://reviews.llvm.org/D58780

llvm-svn: 355196
2019-03-01 10:58:45 +00:00
George Rimar f56def4ea4 [LLD][ELF] - Convert invalid/undefined-local-symbol-in-dso.test to use YAML
This removes a binary from the inputs and reduces the test case.

Differential revision: https://reviews.llvm.org/D58783

llvm-svn: 355194
2019-03-01 10:37:51 +00:00
Peter Collingbourne 7fb9eabda5 ELF: Write .eh_frame_hdr explicitly after writing .eh_frame.
This lets us remove the special case from Writer::writeSections(), and also
fixes a bug where .eh_frame_hdr isn't necessarily written in the correct
order if a linker script moves .eh_frame and .eh_frame_hdr into the same
output section.

Differential Revision: https://reviews.llvm.org/D58795

llvm-svn: 355153
2019-02-28 23:11:35 +00:00
George Rimar c6846b8800 [LLD][ELF] - Stop using binary input in invalid/tls-symbol.s test. NFCI.
We can use yaml2obj instead, patch does this.

llvm-svn: 355075
2019-02-28 09:24:12 +00:00
George Rimar cc19dc75fb [LLD][ELF] - Improve "sh_addralign is not a power of 2" diagnostics.
This patch removes the precompiled binary from inputs,
replacing it with a YAML. And teaches LLD to report a
section name in case of such error.

Differential revision: https://reviews.llvm.org/D58670

llvm-svn: 354959
2019-02-27 10:28:23 +00:00
Bill Wendling 01706bda5b Output ELF files after ThinLTO is run.
Summary:
The gold linker allowed you to output the ELF files after LTO was run. It did
it by using the 'obj-path' option. This replicates that behavior.

Reviewers: espindola, ruiu, MaskRay, pcc

Reviewed By: MaskRay, pcc

Subscribers: grimar, emaste, inglorion, arichardson, steven_wu, dexonsmith, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D56046

llvm-svn: 354917
2019-02-26 19:29:14 +00:00
Simon Atanasyan 478cd32bcb [mips] Reduce number of tools invocations in the test. NFC
llvm-svn: 354772
2019-02-25 11:30:33 +00:00
Peter Smith 777e1cfdc3 [ELF][ARM] Accept and ignore -p and -no-pipleline-knowledge
The linux kernel uses an old flag -p/-no-pipeline-knowledge that is
accepted by bfd and gold but ignored by modern versions of them. The
original option is very old and is pre-ABI, it sometimes comes up in
code-bases that had support for pre ABI toolchains. The Linux kernel uses
it in 3 places in the ARM specific section.

Differential Revision: https://reviews.llvm.org/D58540

llvm-svn: 354769
2019-02-25 10:48:31 +00:00
James Henderson 0cc32dd4a1 [ELF][test]Remove unnecessary empty symbol references in yaml/add missing symbols for relocs
yaml2obj used to require the Symbol field in relocations, but it hasn't
done so for a couple of years. Another change to yaml2obj will soon land
that will look up the symbol by name or index, if present, and emit an
error if not found. This will mean that an explicit symbol reference
(even to an empty-named symbol) that does not reference a symbol
declared in the yaml will result in an error.

This patch updates tests that would otherwise start emitting errors.

Reviewed by: ruiu, grimar

Differential Revision: https://reviews.llvm.org/D58508

llvm-svn: 354666
2019-02-22 11:22:39 +00:00
George Rimar b173d75c49 [LLD][ELF] - Simplify test case. NFC.
It has an excessive section declaration.

llvm-svn: 354573
2019-02-21 12:18:22 +00:00
Simon Atanasyan 14b09810a0 [mips] Put some MIPS-specific sections to separate segments
Three MIPS-specific sections `.reginfo`, `.MIPS.options`, and `.MIPS.abiflags`
are used by loader to read their contents and setup environment for running
a program. Loader looks up these data in the corresponding segments:
`PT_MIPS_REGINFO`, `PT_MIPS_OPTIONS`, and `PT_MIPS_ABIFLAGS` respectively.

This patch put these sections to separate segments like we do already
for ARM `SHT_ARM_EXIDX` section.

Differential Revision: http://reviews.llvm.org/D58381

llvm-svn: 354468
2019-02-20 14:47:02 +00:00
Simon Atanasyan 2fdd159715 [mips] Fix indentations in the test. NFC
llvm-svn: 354341
2019-02-19 16:00:07 +00:00
George Rimar baff199877 [ELF] - Update test case after yaml2obj format change.
yaml2obj was changed in r354338("[yaml2obj][obj2yaml] - Support SHT_GNU_versym (.gnu.version) section.")

llvm-svn: 354339
2019-02-19 15:29:25 +00:00
Simon Atanasyan 37a1d6eca3 Convert the eh-frame-hdr-abs-fde.s test to use x86 as a target architecture
The test checks common functionality. Let's use `x86` (generic LLD target)
as a target architecture.

llvm-svn: 354336
2019-02-19 15:17:43 +00:00
Simon Atanasyan 40fb1c95ee [mips] Remove trailing whitespaces from the test case. NFC
llvm-svn: 354315
2019-02-19 11:15:28 +00:00
Simon Atanasyan a6012a65d4 [mips] Create LA25 thunks for MIPS R6 code
MIPS R6 code uses the `R_MIPS_PC26_S2` relocation for calls which might
cross boundaries of non-PIC-to-PIC code. We need to create a LA25 thunks
for that case.

llvm-svn: 354312
2019-02-19 11:11:12 +00:00
Simon Atanasyan fae2a509fa [MIPS] Handle cross-mode (regular <-> microMIPS) jumps
The patch solves two tasks:

1. MIPS ABI allows to mix regular and microMIPS code and perform
cross-mode jumps. Linker needs to detect such cases and replace
jump/branch instructions by their cross-mode equivalents.

2. Other tools like dunamic linkers need to recognize cases when dynamic
table entries, e_entry field of an ELF header etc point to microMIPS
symbol. Linker should provide such information.

The first task is implemented in the `MIPS<ELFT>::relocateOne()` method.
New routine `fixupCrossModeJump` detects ISA mode change, checks and
replaces an instruction.

The main problem is how to recognize that relocation target is microMIPS
symbol. For absolute and section symbols compiler or assembler set the
less-significant bit of the symbol's value or sum of the symbol's value
and addend. And this bit signals to linker about microMIPS code. For
global symbols compiler cannot do the same trick because other tools like,
for example, disassembler wants to know an actual position of the symbol.
So compiler sets STO_MIPS_MICROMIPS flag in the `st_other` field.

In `MIPS<ELFT>::relocateOne()` method we have a symbol's value only and
cannot access any symbol's attributes. To pass type of the symbol
(regular/microMIPS) to that routine as well as other places where we
write a symbol value as-is (.dynamic section, `Elf_Ehdr::e_entry` field
etc) we set when necessary a less-significant bit in the `getSymVA`
function.

Differential revision: https://reviews.llvm.org/D40147

llvm-svn: 354311
2019-02-19 10:36:58 +00:00
Rui Ueyama 9efdd7ac5e [PPC64] Preserve LocalEntry when linking
On PowerPC64, it is necessary to keep the LocalEntry bits in st_other,
especially when -r is used. Otherwise, when the resulting object is used
in a posterior linking, LocalEntry info will be unavailable and
functions may be called through the wrong entrypoint.

Patch by Leandro Lupori.

Differential Revision: https://reviews.llvm.org/D56782

llvm-svn: 354184
2019-02-15 23:11:18 +00:00
Konstantin Zhuravlyov 87498153aa LLD/AMDGPU: Preserve ABI version during linking ELF for AMDGPU
Differential Revision: https://reviews.llvm.org/D58026

llvm-svn: 354086
2019-02-14 23:59:44 +00:00
Rui Ueyama b8b81e9b43 Improve error message for unknown relocations.
Previously, we showed the following message for an unknown relocation:

  foo.o: unrecognized reloc 256

This patch improves it so that the error message includes a symbol name:

  foo.o: unknown relocation (256) against symbol bar

llvm-svn: 354040
2019-02-14 18:02:20 +00:00
Peter Collingbourne 8331f61a51 ELF: Allow GOT relocs pointing to non-preemptable ifunc to resolve to an IRELATIVE where possible.
Non-GOT non-PLT relocations to non-preemptible ifuncs result in the
creation of a canonical PLT, which now takes the identity of the IFUNC
in the symbol table. This (a) ensures address consistency inside and
outside the module, and (b) fixes a bug where some of these relocations
end up pointing to the resolver.

Fixes (at least) PR40474 and PR40501.

Differential Revision: https://reviews.llvm.org/D57371

llvm-svn: 353981
2019-02-13 21:49:55 +00:00
Rui Ueyama 4134143cf5 Recover elf32-bigmips and elf32-powerpc support in LLD
This fixes a 7.0 -> 8.0 regression when parsing
OUTPUT_FORMAT("elf32-powerpc"); or elf32-bigmips directive in ldscripts
as well as an unknown emulation error when lld is invoked by clang due
to missed elf32ppclinux case.

Patch by vit9696

Differential Revision: https://reviews.llvm.org/D58005

llvm-svn: 353968
2019-02-13 18:51:15 +00:00
Rui Ueyama 265e8e8252 Show "Unknown -z option" error message even if --version or --help are given.
Previously, we validated -z options after we process --version or --help flags.
So, if one of these flags is given, we wouldn't show an "unknown -z option"
error. This patch fixes that behavior.

Differential Revision: https://reviews.llvm.org/D55446

llvm-svn: 353967
2019-02-13 18:48:39 +00:00
Sean Fertile 0205828be4 [PPC64] Update tests to reflect change in printing of call operand. [NFC]
The printing of branch operands for call instructions was changed to properly
handle negative offsets. Updating the tests to reflect that.

llvm-svn: 353866
2019-02-12 17:49:04 +00:00
Rui Ueyama 016833bac2 lld: unquote possibly quoted `EXTERN("symbol")` entry in linker script.
gold accepts quoted strings. binutils requires quoted strings for some
kinds of symbols, e.g.:

  it accepts quoted symbols with @ in name:

  $ echo 'EXTERN("__libc_start_main@@GLIBC_2.2.5")' > a.script
  $ g++ a.script
  /usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../../../lib64/crt1.o: In function `_start':
  (.text+0x20): undefined reference to `main'
  collect2: error: ld returned 1 exit status

  but rejects them if unquoted:

  $ echo 'EXTERN(__libc_start_main@@GLIBC_2.2.5)' > a.script
  $ g++ a.script
  a.script: file not recognized: File format not recognized
  collect2: error: ld returned 1 exit status

To maintain compatibility with existing linker scripts support quoted
strings in lld as well.

Patch by Lucian Adrian Grijincu.

Differential Revision: https://reviews.llvm.org/D57987

llvm-svn: 353756
2019-02-11 22:01:32 +00:00
Rui Ueyama 031fe10927 Convert CRLF. NFC.
llvm-svn: 353751
2019-02-11 21:38:20 +00:00
George Rimar 85ff1b5420 [LLD][ELF] - Update test case after yaml2obj change. NFCI.
.dynamic section format accepted by yaml2obj was
changed in r353606

llvm-svn: 353607
2019-02-09 11:34:59 +00:00
Fangrui Song 283d103bde [ELF] Delete a comment that is no longer correct. Fix a typo. NFC
llvm-svn: 353605
2019-02-09 10:09:40 +00:00
David L. Jones c5cb2ce905 [LLD][ELF] Ensure tests use -o /dev/null instead of attempting to write to the bin directory. [NFC]
This error was introduced in r353508.

llvm-svn: 353602
2019-02-09 05:00:50 +00:00
James Henderson 6bb9b5943f [LLD][ELF]Add test for missing thin archive member
The code producing error messages relating to missing thin archive
members was missing any testing as far as I could see, so this patch
adds a test for it.

Reviewed by: ruiu

Differential Revision: https://reviews.llvm.org/D57899

llvm-svn: 353508
2019-02-08 10:31:38 +00:00
Rui Ueyama 04cbd988f9 Fix a bug in R_X86_64_PC{8,16} relocation handling.
R_X86_64_PC{8,16} relocations are sign-extended, so when we check
for relocation overflow, we had to use checkInt instead of checkUInt.
I confirmed that GNU linkers create the same output for the test case.

llvm-svn: 353437
2019-02-07 18:12:57 +00:00
George Rimar 55f7c72bea [LLD][ELF] - Set DF_STATIC_TLS flag for X64 target
This is the same as D57749, but for x64 target.

"ELF Handling For Thread-Local Storage" p41 says (https://www.akkadia.org/drepper/tls.pdf):
R_X86_64_GOTTPOFF relocation is used for IE TLS models.
Hence if linker sees this relocation we should add DF_STATIC_TLS flag.

Differential revision: https://reviews.llvm.org/D57821

llvm-svn: 353378
2019-02-07 07:59:43 +00:00
Rui Ueyama 33dbcbb2bc Support R_X86_64_PC8 and R_X86_64_PC16.
They are defined by the x86-64 ELF ABI standard.

Differential Revision: https://reviews.llvm.org/D57799

llvm-svn: 353314
2019-02-06 16:50:09 +00:00
George Rimar ae54e58b90 Recommit r353293 "[LLD][ELF] - Set DF_STATIC_TLS flag for i386 target."
With the following changes:
1) Compilation fix:
std::atomic<bool> HasStaticTlsModel = false; ->
std::atomic<bool> HasStaticTlsModel{false};

2) Adjusted the comment in code.

Initial commit message:

DF_STATIC_TLS flag indicates that the shared object or executable
contains code using a static thread-local storage scheme.

Patch checks if IE/LE relocations were used to check if the code uses
a static model. If so it sets the DF_STATIC_TLS flag.

Differential revision: https://reviews.llvm.org/D57749
----
Modified : /lld/trunk/ELF/Arch/X86.cpp
Modified : /lld/trunk/ELF/Config.h
Modified : /lld/trunk/ELF/SyntheticSections.cpp
Added : /lld/trunk/test/ELF/Inputs/i386-static-tls-model1.s
Added : /lld/trunk/test/ELF/Inputs/i386-static-tls-model2.s
Added : /lld/trunk/test/ELF/Inputs/i386-static-tls-model3.s
Added : /lld/trunk/test/ELF/Inputs/i386-static-tls-model4.s
Added : /lld/trunk/test/ELF/i386-static-tls-model.s
Modified : /lld/trunk/test/ELF/i386-tls-ie-shared.s
Modified : /lld/trunk/test/ELF/tls-dynamic-i686.s
Modified : /lld/trunk/test/ELF/tls-opt-iele-i686-nopic.s

llvm-svn: 353299
2019-02-06 14:43:30 +00:00
George Rimar 52fafcb919 Revert r353293 "[LLD][ELF] - Set DF_STATIC_TLS flag for i386 target."
It broke BB:
http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-ubuntu-fast/builds/43450
http://lab.llvm.org:8011/builders/lld-x86_64-freebsd/builds/27891

Error is:
tools/lld/ELF/Config.h:84:41: error: copying member subobject of type
'std::atomic<bool>' invokes deleted constructor std::atomic<bool> HasStaticTlsModel = false;

llvm-svn: 353297
2019-02-06 13:53:32 +00:00
George Rimar da60ad220b [LLD][ELF] - Set DF_STATIC_TLS flag for i386 target.
DF_STATIC_TLS flag indicates that the shared object or executable
contains code using a static thread-local storage scheme.

Patch checks if IE/LE relocations were used to check if the code uses
a static model. If so it sets the DF_STATIC_TLS flag.

Differential revision: https://reviews.llvm.org/D57749

llvm-svn: 353293
2019-02-06 13:38:10 +00:00
Peter Smith aa192bb776 [ELF][ARM] Add test case that will fail if toPlt() is removed [NFC]
When a thunk is created to a PLT entry, the call to the thunk is converted
to a non-plt expression with fromPlt(). If the thunk becomes unusable we
retarget the relocation back to its original target and try again. When we
do this we need to make sure that we restore the PLT form of the expression
with toPlt().

This change adds a test case that will fail if toPlt() is removed. We need
to have a call to a preemptible symbol defined within the link unit. If
toPlt() is removed then the relocation to the thunk to the PLT entry for the
preemptible symbol will be retargeted to the preemptible symbol itself
instead of its PLT entry.

Differential Revision: https://reviews.llvm.org/D57743

llvm-svn: 353285
2019-02-06 10:03:05 +00:00
Fangrui Song c1950aa183 [PPC64] Delete the unnecessary __tls_get_addr from ppc64-tls-ld-le.s
The definition is harmful here as it suppresses R_PPC64_REL24 which is
supposed to follow R_PPC64_TLSLD.

llvm-svn: 353263
2019-02-06 02:13:40 +00:00
Fangrui Song f55e9a2d2e [PPC64] Set the number of relocations processed for R_PPC64_TLS[GL]D to 2
Summary:
R_PPC64_TLSGD and R_PPC64_TLSLD are used as markers on TLS code sequences. After GD-to-IE or GD-to-LE relaxation, the next relocation R_PPC64_REL24 should be skipped to not create a false dependency on __tls_get_addr. When linking statically, the false dependency may cause an "undefined symbol: __tls_get_addr" error.

R_PPC64_GOT_TLSGD16_HA
R_PPC64_GOT_TLSGD16_LO
R_PPC64_TLSGD R_TLSDESC_CALL
R_PPC64_REL24 __tls_get_addr

Reviewers: ruiu, sfertile, syzaara, espindola

Reviewed By: sfertile

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D57673

llvm-svn: 353262
2019-02-06 02:00:24 +00:00
Sam Clegg edd2e05851 [ELF] Fix typo in test/ELF/trace.s
Differential Revision: https://reviews.llvm.org/D57796

llvm-svn: 353254
2019-02-06 01:00:49 +00:00
Matt Davis 0d0e9c08a4 [llvm-readobj] Display sections that do not belong to a segment in the section-mapping
Summary:
The following patch adds the "None" line to the section to segment mapping dump.
That line lists the sections that do not belong to any segment.
I realize that this change differs from GNU readelf which does not display the latter information.

I'd rather not add this "feature" under a command line option.  I think that might introduce confusion, since users would have to
make an additional decision as to if they want to see all of the section-to-segment map or just a subset of it.

Another option is to only print the "None" line if the `--section-mapping` option is passed; however,
that might also introduce some confusion, because the section-to-segment map would be different between`--program-headers`
and the `--section-mapping` output.  While the difference is just the "None" line, it seems that if we choose to display
the segment-to-section mapping, then we should always display the whole map including the sections
that do not belong to segments.

```
Section to Segment mapping:
  Segment Sections...
   00
   01     .interp
   02     .interp .note.ABI-tag .gnu.hash
   03     .init_array .fini_array .dynamic
   04     .dynamic
   05     .note.ABI-tag
   06     .eh_frame_hdr
   07
   08     .init_array .fini_array .dynamic .got
   None   .comment .symtab .strtab .shstrtab <--- THIS LINE
```

Reviewers: grimar, rupprecht, jhenderson, espindola

Reviewed By: rupprecht

Subscribers: khemant, emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D57700

llvm-svn: 353217
2019-02-05 21:01:01 +00:00
Fangrui Song ae0294375f [ELF] Default to --no-allow-shlib-undefined for executables
Summary:
This follows the ld.bfd/gold behavior.

The error check is useful as it captures a common type of ld.so undefined symbol errors as link-time errors:

    // a.cc => a.so (not linked with -z defs)
    void f(); // f is undefined
    void g() { f(); }

    // b.cc => executable with a DT_NEEDED entry on a.so
    void g();
    int main() { g(); }

    // ld.so errors when g() is executed (lazy binding) or when the program is started (-z now)
    // symbol lookup error: ... undefined symbol: f

Reviewers: ruiu, grimar, pcc, espindola

Reviewed By: ruiu

Subscribers: llvm-commits, emaste, arichardson

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D57569

llvm-svn: 352943
2019-02-02 00:34:28 +00:00
Fangrui Song b4744d306c [ELF] Support --{,no-}allow-shlib-undefined
Summary:
In ld.bfd/gold, --no-allow-shlib-undefined is the default when linking
an executable. This patch implements a check to error on undefined
symbols in a shared object, if all of its DT_NEEDED entries are seen.

Our approach resembles the one used in gold, achieves a good balance to
be useful but not too smart (ld.bfd traces all DSOs and emulates the
behavior of a dynamic linker to catch more cases).

The error is issued based on the symbol table, different from undefined
reference errors issued for relocations. It is most effective when there
are DSOs that were not linked with -z defs (e.g. when static sanitizers
runtime is used).

gold has a comment that some system libraries on GNU/Linux may have
spurious undefined references and thus system libraries should be
excluded (https://sourceware.org/bugzilla/show_bug.cgi?id=6811). The
story may have changed now but we make --allow-shlib-undefined the
default for now. Its interaction with -shared can be discussed in the
future.

Reviewers: ruiu, grimar, pcc, espindola

Reviewed By: ruiu

Subscribers: joerg, emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D57385

llvm-svn: 352826
2019-02-01 02:25:05 +00:00
Dimitry Andric 19b134cc44 Recognize FreeBSD specific BFD names in OUTPUT_FORMAT
Summary:
After rLLD344952 ("Add OUTPUT_FORMAT linker script directive support"),
using BFD names such as `elf64-x86-64-freebsd` the `OUTPUT_FORMAT`
linker script command does not work anymore, resulting in errors like:

```
ld: error: /home/dim/src/clang800-import/stand/efi/loader/arch/amd64/ldscript.amd64:2: unknown output format name: elf64-x86-64-freebsd
>>> OUTPUT_FORMAT("elf64-x86-64-freebsd", "elf64-x86-64-freebsd", "elf64-x86-64-freebsd")
>>>               ^
```

To fix this, recognize a `-freebsd` suffix in BFD names, and also set
`Configuration::OSABI` to `ELFOSABI_FREEBSD` for those cases.

Add and/or update several test cases to check for the correct results of
these new `OUTPUT_FORMAT` arguments.

Reviewers: ruiu, atanasyan, grimar, hokein, emaste, espindola

Reviewed By: ruiu

Subscribers: nemanjai, javed.absar, arichardson, krytarowski, kristof.beyls, kbarton, llvm-commits

Differential Revision: https://reviews.llvm.org/D57283

llvm-svn: 352606
2019-01-30 06:31:52 +00:00
Peter Collingbourne ff35dbac47 ELF: Set sh_info on RelaIplt to point to the IgotPlt output section.
Previously we were setting it to the GotPlt output section, which is
incorrect on ARM where this section is in .got. In static binaries
this can lead to sh_info being set to -1 (because there is no .got.plt)
which results in various tools rejecting the output file.

Differential Revision: https://reviews.llvm.org/D57274

llvm-svn: 352413
2019-01-28 19:29:41 +00:00
George Rimar 8bb8433a1a [LLD][ELF] - Update tests after r352366.
r352366 "[llvm-objdump] - Print LMAs when dumping section headers." changed the format of
llvm-objdump output. We have to update the LLD tests.

llvm-svn: 352372
2019-01-28 15:03:47 +00:00
Nick Desaulniers 6cff0cb35a lld: elf: discard more specific .gnu.linkonce section
Summary:
lld discards .gnu.linonce.* sections work around a bug in glibc.
https://sourceware.org/bugzilla/show_bug.cgi?id=20543

Unfortunately, the Linux kernel uses a section named
.gnu.linkonce.this_module to store infomation about kernel modules. The
kernel reads data from this section when loading kernel modules, and
errors if it fails to find this section. The current behavior of lld
discards this section when kernel modules are linked, so kernel modules
linked with lld are unloadable by the linux kernel.

The Linux kernel should use a comdat section instead of .gnu.linkonce.
The minimum version of binutils supported by the kernel supports comdat
sections. The kernel is also not relying on the old linkonce behavior;
it seems to have chosen a name that contains a deprecated GNU feature.

Changing the section name now in the kernel would require all kernel
modules to be recompiled to make use of the new section name. Instead,
rather than discarding .gnu.linkonce.*, let's discard the more specific
section name to continue working around the glibc issue while supporting
linking Linux kernel modules.

Link: https://github.com/ClangBuiltLinux/linux/issues/329

Reviewers: pcc, espindola

Reviewed By: pcc

Subscribers: nathanchance, emaste, arichardson, void, srhines

Differential Revision: https://reviews.llvm.org/D57294

llvm-svn: 352302
2019-01-27 02:54:23 +00:00
Sean Fertile 83cb252876 [PPC64] Reland r351978 'Sort .toc sections accessed with small code model ...'
Guessing that the slashes used in the scripts SECTION command was causing the
windows related failures in the added test.

Original commit message:
Small code model global variable access on PPC64 has a very limited range of
addressing. The instructions the relocations are used on add an offset in the
range [-0x8000, 0x7FFC] to the toc pointer which points to .got +0x8000, giving
an addressable range of [.got, .got + 0xFFFC]. While user code can be recompiled
with medium and large code models when the binary grows too large for small code
model, there are small code model relocations in the crt files and libgcc.a
which are typically shipped with the distros, and the ABI dictates that linkers
must allow linking of relocatable object files using different code models.

To minimze the chance of relocation overflow, any file that contains a small
code model relocation should have its .toc section placed closer to the .got
then any .toc from a file without small code model relocations.

Differential Revision: https://reviews.llvm.org/D56920

llvm-svn: 352071
2019-01-24 18:17:40 +00:00
Serge Guelton 1fa239f500 Partial support of SHT_GROUP without flag
This does *not* implement full SHT_GROUP semantic, yet it is a simple step forward:
Sections within a group are still considered valid, but they do not behave as
specified by the standard in case of garbage collection.

Differential Revision: https://reviews.llvm.org/D56437

llvm-svn: 352068
2019-01-24 17:56:08 +00:00
Sean Fertile 72679cff12 Revert "[PPC64] Sort .toc sections accessed with small code model ..."
This reverts commit ca87c57a3aa4770c9cf0defd4b2feccbc342ee93.
Added test fails on several windows buildbots.

llvm-svn: 351985
2019-01-23 21:46:28 +00:00
Sean Fertile a010cf615a [PPC64] Sort .toc sections accessed with small code model relocs close to .got.
Small code model global variable access on PPC64 has a very limited range of
addressing. The instructions the relocations are used on add an offset in the
range [-0x8000, 0x7FFC] to the toc pointer which points to .got +0x8000, giving
an addressable range of [.got, .got + 0xFFFC]. While user code can be recompiled
with medium and large code models when the binary grows too large for small code
model, there are small code model relocations in the crt files and libgcc.a
which are typically shipped with the distros, and the ABI dictates that linkers
must allow linking of relocatable object files using different code models.

To minimze the chance of relocation overflow, any file that contains a small
code model relocation should have its .toc section placed closer to the .got
then any .toc from a file without small code model relocations.

Differential Revision: https://reviews.llvm.org/D56920

llvm-svn: 351978
2019-01-23 21:04:03 +00:00
Nico Weber 8874aef822 Disable test better.
llvm-svn: 351952
2019-01-23 13:43:42 +00:00
Nico Weber 53c3c2c61c Disable test added in r351916.
It doesn't pass on Windows:
http://lab.llvm.org:8011/builders/clang-x64-windows-msvc/builds/3627

FAIL: lld :: ELF/stdout.s (1521 of 1966)
******************** TEST 'lld :: ELF/stdout.s' FAILED ********************
Script:
--
: 'RUN: at line 3';   C:\b\slave\clang-x64-windows-msvc\build\build\stage1\bin\llvm-mc.EXE -filetype=obj -triple=x86_64-unknown-linux C:\b\slave\clang-x64-windows-msvc\build\llvm.src\tools\lld\test\ELF\stdout.s -o C:\b\slave\clang-x64-windows-msvc\build\build\stage1\tools\lld\test\ELF\Output\stdout.s.tmp.o
: 'RUN: at line 4';   c:\b\slave\clang-x64-windows-msvc\build\build\stage1\bin\ld.lld.EXE C:\b\slave\clang-x64-windows-msvc\build\build\stage1\tools\lld\test\ELF\Output\stdout.s.tmp.o -o - > C:\b\slave\clang-x64-windows-msvc\build\build\stage1\tools\lld\test\ELF\Output\stdout.s.tmp1
: 'RUN: at line 5';   C:\b\slave\clang-x64-windows-msvc\build\build\stage1\bin\llvm-objdump.EXE -d C:\b\slave\clang-x64-windows-msvc\build\build\stage1\tools\lld\test\ELF\Output\stdout.s.tmp1 | C:\b\slave\clang-x64-windows-msvc\build\build\stage1\bin\FileCheck.EXE C:\b\slave\clang-x64-windows-msvc\build\llvm.src\tools\lld\test\ELF\stdout.s
: 'RUN: at line 10';   c:\b\slave\clang-x64-windows-msvc\build\build\stage1\bin\ld.lld.EXE C:\b\slave\clang-x64-windows-msvc\build\build\stage1\tools\lld\test\ELF\Output\stdout.s.tmp.o -o C:\b\slave\clang-x64-windows-msvc\build\build\stage1\tools\lld\test\ELF\Output\stdout.s.tmp2
: 'RUN: at line 11';   diff C:\b\slave\clang-x64-windows-msvc\build\build\stage1\tools\lld\test\ELF\Output\stdout.s.tmp1 C:\b\slave\clang-x64-windows-msvc\build\build\stage1\tools\lld\test\ELF\Output\stdout.s.tmp2
--
Exit Code: 1

Command Output (stdout):
--
$ ":" "RUN: at line 3"
$ "C:\b\slave\clang-x64-windows-msvc\build\build\stage1\bin\llvm-mc.EXE" "-filetype=obj" "-triple=x86_64-unknown-linux" "C:\b\slave\clang-x64-windows-msvc\build\llvm.src\tools\lld\test\ELF\stdout.s" "-o" "C:\b\slave\clang-x64-windows-msvc\build\build\stage1\tools\lld\test\ELF\Output\stdout.s.tmp.o"
$ ":" "RUN: at line 4"
$ "c:\b\slave\clang-x64-windows-msvc\build\build\stage1\bin\ld.lld.EXE" "C:\b\slave\clang-x64-windows-msvc\build\build\stage1\tools\lld\test\ELF\Output\stdout.s.tmp.o" "-o" "-"
$ ":" "RUN: at line 5"
$ "C:\b\slave\clang-x64-windows-msvc\build\build\stage1\bin\llvm-objdump.EXE" "-d" "C:\b\slave\clang-x64-windows-msvc\build\build\stage1\tools\lld\test\ELF\Output\stdout.s.tmp1"
$ "C:\b\slave\clang-x64-windows-msvc\build\build\stage1\bin\FileCheck.EXE" "C:\b\slave\clang-x64-windows-msvc\build\llvm.src\tools\lld\test\ELF\stdout.s"
$ ":" "RUN: at line 10"
$ "c:\b\slave\clang-x64-windows-msvc\build\build\stage1\bin\ld.lld.EXE" "C:\b\slave\clang-x64-windows-msvc\build\build\stage1\tools\lld\test\ELF\Output\stdout.s.tmp.o" "-o" "C:\b\slave\clang-x64-windows-msvc\build\build\stage1\tools\lld\test\ELF\Output\stdout.s.tmp2"
$ ":" "RUN: at line 11"
$ "diff" "C:\b\slave\clang-x64-windows-msvc\build\build\stage1\tools\lld\test\ELF\Output\stdout.s.tmp1" "C:\b\slave\clang-x64-windows-msvc\build\build\stage1\tools\lld\test\ELF\Output\stdout.s.tmp2"
# command output:
*** C:\b\slave\clang-x64-windows-msvc\build\build\stage1\tools\lld\test\ELF\Output\stdout.s.tmp1
--- C:\b\slave\clang-x64-windows-msvc\build\build\stage1\tools\lld\test\ELF\Output\stdout.s.tmp2
***************
*** 1 ****

llvm-svn: 351949
2019-01-23 12:35:08 +00:00