Commit Graph

12866 Commits

Author SHA1 Message Date
Peter Smith 4f38ab250f [LLD][ELF][ARM] Do not insert interworking thunks for non STT_FUNC symbols
ELF for the ARM architecture requires linkers to provide
interworking for symbols that are of type STT_FUNC. Interworking for
other symbols must be encoded directly in the object file. LLD was always
providing interworking, regardless of the symbol type, this breaks some
programs that have branches from Thumb state targeting STT_NOTYPE symbols
that have bit 0 clear, but they are in fact internal labels in a Thumb
function. LLD treats these symbols as ARM and inserts a transition to Arm.

This fixes the problem for in range branches, R_ARM_JUMP24,
R_ARM_THM_JUMP24 and R_ARM_THM_JUMP19. This is expected to be the vast
majority of problem cases as branching to an internal label close to the
function.

There is at least one follow up patch required.
- R_ARM_CALL and R_ARM_THM_CALL may do interworking via BL/BLX
  substitution.

In theory range-extension thunks can be altered to not change state when
the symbol type is not STT_FUNC. I will need to check with ld.bfd to see if
this is the case in practice.

Fixes (part of) https://github.com/ClangBuiltLinux/linux/issues/773

Differential Revision: https://reviews.llvm.org/D73474
2020-01-28 11:54:18 +00:00
Peter Smith 3238b03c19 [LLD][ELF][ARM] clang-format function signature [NFC]
ARM::needsThunk had gone over 80 characters, run clang-format over it to
prevent it wrapping.
2020-01-28 11:54:18 +00:00
Teresa Johnson 2f63d549f1 Restore "[LTO/WPD] Enable aggressive WPD under LTO option"
This restores 59733525d3 (D71913), along
with bot fix 19c76989bb.

The bot failure should be fixed by D73418, committed as
af954e441a.

I also added a fix for non-x86 bot failures by requiring x86 in new test
lld/test/ELF/lto/devirt_vcall_vis_public.ll.
2020-01-27 07:55:05 -08:00
Fangrui Song 70389be7a0 [ELF][PPC32] Support range extension thunks with addends
* Generalize the code added in D70637 and D70937. We should eventually remove the EM_MIPS special case.
* Handle R_PPC_LOCAL24PC the same way as R_PPC_REL24.

Reviewed By: Bdragon28

Differential Revision: https://reviews.llvm.org/D73424
2020-01-25 22:32:42 -08:00
Fangrui Song 837e8a9c0c [ELF][PPC32] Support canonical PLT
-fno-pie produces a pair of non-GOT-non-PLT relocations R_PPC_ADDR16_{HA,LO} (R_ABS) referencing external
functions.

```
lis 3, func@ha
la 3, func@l(3)
```

In a -no-pie/-pie link, if func is not defined in the executable, a canonical PLT entry (st_value>0, st_shndx=0) will be needed.
References to func in shared objects will be resolved to this address.
-fno-pie -pie should fail with "can't create dynamic relocation ... against ...", so we just need to think about -no-pie.

On x86, the PLT entry passes the JMP_SLOT offset to the rtld PLT resolver.
On x86-64: the PLT entry passes the JUMP_SLOT index to the rtld PLT resolver.
On ARM/AArch64: the PLT entry passes &.got.plt[n]. The PLT header passes &.got.plt[fixed-index]. The rtld PLT resolver can compute the JUMP_SLOT index from the two addresses.

For these targets, the canonical PLT entry can just reuse the regular PLT entry (in PltSection).

On PPC32: PltSection (.glink) consists of `b PLTresolve` instructions and `PLTresolve`. The rtld PLT resolver depends on r11 having been set up to the .plt (GotPltSection) entry.
On PPC64 ELFv2: PltSection (.glink) consists of `__glink_PLTresolve` and `bl __glink_PLTresolve`. The rtld PLT resolver depends on r12 having been set up to the .plt (GotPltSection) entry.

We cannot reuse a `b PLTresolve`/`bl __glink_PLTresolve` in PltSection as a canonical PLT entry. PPC64 ELFv2 avoids the problem by using TOC for any external reference, even in non-pic code, so the canonical PLT entry scenario should not happen in the first place.
For PPC32, we have to create a PLT call stub as the canonical PLT entry. The code sequence sets up r11.

Reviewed By: Bdragon28

Differential Revision: https://reviews.llvm.org/D73399
2020-01-25 17:56:37 -08:00
Fangrui Song deb5819d62 [ELF] Rename relocateOne() to relocate() and pass `Relocation` to it
Symbol information can be used to improve out-of-range/misalignment diagnostics.
It also helps R_ARM_CALL/R_ARM_THM_CALL which has different behaviors with different symbol types.

There are many (67) relocateOne() call sites used in thunks, {Arm,AArch64}errata, PLT, etc.
Rename them to `relocateNoSym()` to be clearer that there is no symbol information.

Reviewed By: grimar, peter.smith

Differential Revision: https://reviews.llvm.org/D73254
2020-01-25 12:00:18 -08:00
Fangrui Song f1dab29908 [ELF][PowerPC] Support R_PPC_COPY and R_PPC64_COPY
Reviewed By: Bdragon28, jhenderson, grimar, sfertile

Differential Revision: https://reviews.llvm.org/D73255
2020-01-24 09:06:20 -08:00
Teresa Johnson 90e630a95e Revert "[LTO/WPD] Enable aggressive WPD under LTO option"
This reverts commit 59733525d3.

There is a windows sanitizer bot failure in one of the cfi tests
that I will need some time to figure out:
http://lab.llvm.org:8011/builders/sanitizer-windows/builds/57155/steps/stage%201%20check/logs/stdio
2020-01-23 17:29:24 -08:00
Teresa Johnson 59733525d3 [LTO/WPD] Enable aggressive WPD under LTO option
Summary:
Third part in series to support Safe Whole Program Devirtualization
Enablement, see RFC here:
http://lists.llvm.org/pipermail/llvm-dev/2019-December/137543.html

This patch adds type test metadata under -fwhole-program-vtables,
even for classes without hidden visibility. It then changes WPD to skip
devirtualization for a virtual function call when any of the compatible
vtables has public vcall visibility.

Additionally, internal LLVM options as well as lld and gold-plugin
options are added which enable upgrading all public vcall visibility
to linkage unit (hidden) visibility during LTO. This enables the more
aggressive WPD to kick in based on LTO time knowledge of the visibility
guarantees.

Support was added to all flavors of LTO WPD (regular, hybrid and
index-only), and to both the new and old LTO APIs.

Unfortunately it was not simple to split the first and second parts of
this part of the change (the unconditional emission of type tests and
the upgrading of the vcall visiblity) as I needed a way to upgrade the
public visibility on legacy WPD llvm assembly tests that don't include
linkage unit vcall visibility specifiers, to avoid a lot of test churn.

I also added a mechanism to LowerTypeTests that allows dropping type
test assume sequences we now aggressively insert when we invoke
distributed ThinLTO backends with null indexes, which is used in testing
mode, and which doesn't invoke the normal ThinLTO backend pipeline.

Depends on D71907 and D71911.

Reviewers: pcc, evgeny777, steven_wu, espindola

Subscribers: emaste, Prazek, inglorion, arichardson, hiraditya, MaskRay, dexonsmith, dang, davidxl, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D71913
2020-01-23 16:09:44 -08:00
Fangrui Song 0fbf28f7aa [ELF] --no-dynamic-linker: don't emit undefined weak symbols to .dynsym
I felt really sad to push this commit for my selfish purpose to make
glibc -static-pie build with lld. Some code constructs in glibc require
R_X86_64_GOTPCREL/R_X86_64_REX_GOTPCRELX referencing undefined weak to
be resolved to a GOT entry not relocated by R_X86_64_GLOB_DAT (GNU ld
behavior), e.g.

csu/libc-start.c
  if (__pthread_initialize_minimal != NULL)
    __pthread_initialize_minimal ();

elf/dl-object.c
  void
  _dl_add_to_namespace_list (struct link_map *new, Lmid_t nsid)
  {
    /* We modify the list of loaded objects.  */
    __rtld_lock_lock_recursive (GL(dl_load_write_lock));

Emitting a GLOB_DAT will make the address equal &__ehdr_start (true
value) and cause elf/ldconfig to segfault. glibc really should move away
from weak references, which do not have defined semantics.

Temporarily special case --no-dynamic-linker.
2020-01-23 12:25:15 -08:00
Reid Kleckner e5caa156b4 [PDB] Simplify API for making section map, NFC
Prevents API misuse described in PR44495
2020-01-23 12:15:21 -08:00
Fangrui Song 1e57038bf2 [ELF] Pass `Relocation` to relaxGot and relaxTls{GdToIe,GdToLe,LdToLe,IeToLe}
These functions call relocateOne(). This patch is a prerequisite for
making relocateOne() aware of `Symbol` (D73254).

Reviewed By: grimar, nickdesaulniers

Differential Revision: https://reviews.llvm.org/D73250
2020-01-23 10:39:25 -08:00
Martin Storsjö e6b0ce70bd [LLD] [COFF] Silence a GCC warning about an unused variable. NFC. 2020-01-23 13:23:56 +02:00
Markus Böck 9dbc1ab232 [LLD][COFF] Enable linking of __declspec(selectany) symbols from Clang and GCC
When annotating a symbol with __declspec(selectany), Clang assigns it
comdat 2 while GCC assigns it comdat 3. This patch enables two object
files that contain a __declspec(selectany) symbol, one created by gcc
and the other by clang, to be linked together instead of issuing a
duplicate symbol error.

Differential Revision: https://reviews.llvm.org/D73139
2020-01-23 10:55:27 +02:00
James Clarke ddfe8751b1 [test] Fix lld/test/ELF/riscv-pcrel-hilo-error.s after D73211 2020-01-23 02:30:10 +00:00
Thomas Preud'homme c42fe24754 [lld/ELF] PR44498: Support input filename in double quote
Summary:
Linker scripts allow filenames to be put in double quotes to prevent
characters in filenames that are part of the linker script syntax from
having their special meaning. Case in point the * wildcard character.

Availability of double quoting filenames also allows to fix a failure in
ELF/linkerscript/filename-spec.s when the path contain a @ which the
lexer consider as a special characters and thus break up a filename
containing it. This may happens under Jenkins which createspath such as
pipeline@2.

To avoid the need for escaping GlobPattern metacharacters in filename
in double quotes, GlobPattern::create is augmented with a new parameter
to request literal matching instead of relying on the presence of a
wildcard character in the pattern.

Reviewers: jhenderson, MaskRay, evgeny777, espindola, alexshap

Reviewed By: MaskRay

Subscribers: peter.smith, grimar, ruiu, emaste, arichardson, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D72517
2020-01-22 12:03:10 +00:00
Peter Smith e727f39ec0 [LLD][ELF][ARM] Don't apply --fix-cortex-a8 to relocatable links.
The --fix-cortex-a8 is sensitive to alignment and the precise destination
of branch instructions. These are not knowable at relocatable link time. We
follow GNU ld and the --fix-cortex-a53-843419 (D72968) by not patching the
code when there is a relocatable link.

Differential Revision: https://reviews.llvm.org/D73100
2020-01-22 11:03:40 +00:00
Sid Manning 6b9a5e6f05 [lld][Hexagon] Add General Dynamic relocations (GD)
Differential revision: https://reviews.llvm.org/D72522
2020-01-21 14:10:03 -06:00
Andrew Ng 4e8116f469 [ELF] Refactor uses of getInputSections to improve efficiency NFC
Add new method getFirstInputSection and use instead of getInputSections
where appropriate to avoid creation of an unneeded vector of input
sections.

Differential Revision: https://reviews.llvm.org/D73047
2020-01-21 12:27:52 +00:00
Peter Smith dbd0ad3366 [LLD][ELF] Add support for INPUT_SECTION_FLAGS
The INPUT_SECTION_FLAGS linker script command is used to constrain the
section pattern matching to sections that match certain combinations of
flags.

There are two ways to express the constraint.
withFlags: Section must have these flags.
withoutFlags: Section must not have these flags.

The syntax of the command is:
INPUT_SECTION_FLAGS '(' sect_flag_list ')'
sect_flag_list: NAME
| sect_flag_list '&' NAME

Where NAME matches a section flag name such as SHF_EXECINSTR, or the
integer value of a section flag. If the first character of NAME is ! then
it means must not contain flag.

We do not support the rare case of { INPUT_SECTION_FLAGS(flags) filespec }
where filespec has no input section description like (.text).

As an example from the ld man page:
SECTIONS {
  .text : { INPUT_SECTION_FLAGS (SHF_MERGE & SHF_STRINGS) *(.text) }
  .text2 :  { INPUT_SECTION_FLAGS (!SHF_WRITE) *(.text) }
}
.text will match sections called .text that have both the SHF_MERGE and
SHF_STRINGS flag.
.text2 will match sections called .text that don't have the SHF_WRITE flag.

The flag names accepted are the generic to all targets and SHF_ARM_PURECODE
as it is very useful to filter all the pure code sections into a single
program header that can be marked execute never.

fixes PR44265

Differential Revision: https://reviews.llvm.org/D72756
2020-01-21 10:05:26 +00:00
Igor Kudrin 6b4f86f65f Reapply: [MachO] Add a test for detecting reserved unit length.
The test in the origin patch did not create a __debug_str section.
An UBSan check triggered when the corresponding pointer was dereferenced.

Differential Revision: https://reviews.llvm.org/D72695

This reapplies fcc08aa835
which was reverted in b16f82ad3b.
2020-01-21 16:59:44 +07:00
Mitch Phillips b16f82ad3b Revert "[MachO] Add a test for detecting reserved unit length."
This change broke the UBSan buildbots. More information available in the
original Phabricator review: https://reviews.llvm.org/D72695

This reverts commit fcc08aa835.
2020-01-20 22:39:24 -08:00
James Clarke d1da63664f [lld][RISCV] Print error when encountering R_RISCV_ALIGN
Summary:
Unlike R_RISCV_RELAX, which is a linker hint, R_RISCV_ALIGN requires the
support of the linker even when ignoring all R_RISCV_RELAX relocations.
This is because the compiler emits as many NOPs as may be required for
the requested alignment, more than may be required pre-relaxation, to
allow for the target becoming more unaligned after relaxing earlier
sequences. This means that the target is often not initially aligned in
the object files, and so the R_RISCV_ALIGN relocations cannot just be
ignored. Since we do not support linker relaxation, we must turn these
into errors.

Reviewers: ruiu, MaskRay, espindola

Reviewed By: MaskRay

Subscribers: grimar, Jim, emaste, arichardson, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, kito-cheng, shiva0217, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, rkruppe, PkmX, jocewei, psnobl, benna, lenary, s.egerton, pzheng, sameer.abuasal, apazos, luismarques, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71820
2020-01-21 02:49:45 +00:00
Eli Friedman c81fe34718 [lld][ELF] Don't apply --fix-cortex-a53-843419 to relocatable links.
The code doesn't apply the fix correctly to relocatable links. I could
try to fix the code that applies the fix, but it's pointless: we don't
actually know what the offset will be in the final executable. So just
ignore the flag for relocatable links.

Issue discovered building Android.

Differential Revision: https://reviews.llvm.org/D72968
2020-01-20 15:27:41 -08:00
Derek Schuff ff171acf84 [WebAssembly] Track frame registers through VReg and local allocation
This change has 2 components:

Target-independent: add a method getDwarfFrameBase to TargetFrameLowering. It
describes how the Dwarf frame base will be encoded.  That can be a register (the
default), the CFA (which replaces NVPTX-specific logic in DwarfCompileUnit), or
a DW_OP_WASM_location descriptr.

WebAssembly: Allow WebAssemblyFunctionInfo::getFrameRegister to return the
correct virtual register instead of FP32/SP32 after WebAssemblyReplacePhysRegs
has run.  Make WebAssemblyExplicitLocals store the local it allocates for the
frame register. Use this local information to implement getDwarfFrameBase

The result is that the DW_AT_frame_base attribute is correctly encoded for each
subprogram, and each param and local variable has a correct DW_AT_location that
uses DW_OP_fbreg to refer to the frame base.

This is a reland of rG3a05c3969c18 with fixes for the expensive-checks
and Windows builds

Differential Revision: https://reviews.llvm.org/D71681
2020-01-17 17:23:56 -08:00
Fangrui Song 6ab89c3c5d [ELF] Allow R_PLT_PC (R_PC) to a hidden undefined weak symbol
This essentially reverts b841e119d7.

Such code construct can be used in the following way:

  // glibc/stdlib/exit.c
  // clang -fuse-ld=lld => succeeded
  // clang -fuse-ld=lld -fpie -pie => relocation R_PLT_PC cannot refer to absolute symbol
  __attribute__((weak, visibility("hidden"))) extern void __call_tls_dtors();
  void __run_exit_handlers() {
    if (__call_tls_dtors)
        __call_tls_dtors();
  }

Since we allow R_PLT_PC in -no-pie mode, it makes sense to allow it in
-pie mode as well.

Reviewed By: pcc

Differential Revision: https://reviews.llvm.org/D72943
2020-01-17 13:06:42 -08:00
Fangrui Song 08f2b67d03 [test] Fix test/ELF/lto/thinlto-obj-path.ll after D52810 2020-01-17 10:13:21 -08:00
Peter Smith 01ad4c8384 [LLD][ELF][ARM][AArch64] Only round up ThunkSection Size when large OS.
In D71281 a fix was put in to round up the size of a ThunkSection to the
nearest 4KiB when performing errata patching. This fixed a problem with a
very large instrumented program that had thunks and patches mutually
trigger each other. Unfortunately it triggers an assertion failure in an
AArch64 allyesconfig build of the kernel. There is a specific assertion
preventing an InputSectionDescription being larger than 4KiB. This will
always trigger if there is at least one Thunk needed in that
InputSectionDescription, which is possible for an allyesconfig build.

Abstractly the problem case is:
.text : {
          *(.text) ;
          ...
          . = ALIGN(SZ_4K);
          __idmap_text_start = .;
          *(.idmap.text)
          __idmap_text_end = .;
          ...
        }
The assertion checks that __idmap_text_end - __idmap_start is < 4 KiB.
Note that there is more than one InputSectionDescription in the
OutputSection so we can't just restrict the fix to OutputSections smaller
than 4 KiB.

The fix presented here limits the D71281 to InputSectionDescriptions that
meet the following conditions:
1.) The OutputSection is bigger than the thunkSectionSpacing so adding
thunks will affect the addresses of following code.
2.) The InputSectionDescription is larger than 4 KiB. This will prevent
any assertion failures that an InputSectionDescription is < 4 KiB
in size.

We do this at ThunkSection creation time as at this point we know that
the addresses are stable and up to date prior to adding the thunks as
assignAddresses() will have been called immediately prior to thunk
generation.

The fix reverts the two tests affected by D71281 to their original state
as they no longer need the 4KiB size roundup. I've added simpler tests to
check for D71281 when the OutputSection size is larger than the ThunkSection
spacing.

Fixes https://github.com/ClangBuiltLinux/linux/issues/812

Differential Revision: https://reviews.llvm.org/D72344
2020-01-17 10:47:21 +00:00
Nico Weber fb5fafb23c Make LLVM_APPEND_VC_REV=OFF affect clang, lld, and lldb as well.
When LLVM_APPEND_VC_REV=OFF is set, the current git hash is no
longer embedded into binaries (mostly for --version output).
Without it, most binaries need to relink after every single
commit, even if they didn't change otherwise (due to, say,
a documentation-only commit).

LLVM_APPEND_VC_REV is ON by default, so this doesn't change the
default behavior of anything.

With this, all clients of GenerateVersionFromVCS.cmake honor
LLVM_APPEND_VC_REV.

Differential Revision: https://reviews.llvm.org/D72855
2020-01-16 19:04:08 -05:00
Sam Clegg 51b521c07a [lld][WebAssembly] Use a more meaningful name for stub functions
When we generate these stub functions on signature mismatches give
them a more meaningful name so that when people see this in stack
traces is gives a clue as the what is going on.

See: https://github.com/emscripten-core/emscripten/issues/10226

Differential Revision: https://reviews.llvm.org/D72881
2020-01-16 14:55:37 -08:00
Derek Schuff 80906d9d16 Revert "[WebAssembly] Track frame registers through VReg and local allocation"
This reverts commit 3a05c3969c.
It breaks under expensive-checks and on Windows
2020-01-16 14:38:00 -08:00
Derek Schuff 3a05c3969c [WebAssembly] Track frame registers through VReg and local allocation
This change has 2 components:

Target-independent: add a method getDwarfFrameBase to TargetFrameLowering. It
describes how the Dwarf frame base will be encoded.  That can be a register (the
default), the CFA (which replaces NVPTX-specific logic in DwarfCompileUnit), or
a DW_OP_WASM_location descriptr.

WebAssembly: Allow WebAssemblyFunctionInfo::getFrameRegister to return the
correct virtual register instead of FP32/SP32 after WebAssemblyReplacePhysRegs
has run.  Make WebAssemblyExplicitLocals store the local it allocates for the
frame register. Use this local information to implement getDwarfFrameBase

The result is that the DW_AT_frame_base attribute is correctly encoded for each
subprogram, and each param and local variable has a correct DW_AT_location that
uses DW_OP_fbreg to refer to the frame base.

Differential Revision: https://reviews.llvm.org/D71681
2020-01-16 13:51:17 -08:00
Fangrui Song 2d7a8cf904 [ELF] -r: don't create .interp
`{clang,gcc} -nostdlib -r a.c` passes --dynamic-linker to the linker,
and the expected behavior is to ignore it.

If .interp is kept in the relocatable object file, a final link will get
PT_INTERP even if --dynamic-linker is not specified. glibc ld.so expects
to see PT_DYNAMIC and the executable will likely fail to run.

Ignore --dynamic-linker in -r mode as well as -shared.
2020-01-16 12:14:32 -08:00
Fangrui Song 870094decf [ELF] Decrease alignment of ThunkSection on 64-bit targets from 8 to 4
ThunkSection contains 4-byte instructions on all targets that use
thunks. Thunks should not be used in any performance sensitive places,
and locality/cache line/instruction fetching arguments should not apply.

We use 16 bytes as preferred function alignments for modern PowerPC cores.
In any case, 8 is not optimal.

Differential Revision: https://reviews.llvm.org/D72819
2020-01-16 10:36:33 -08:00
Nico Weber 4f5c65a5c8 try to unbreak build after 4b6d9ac392 2020-01-16 10:12:35 -05:00
Nico Weber 4b6d9ac392 Make lld cmake not compute commit revision twice
r354605 moved LLD to the unified revision handling introduced in
rL353268 / r352729 and removed uses of LLD_REPOSITORY_STRING and
LLD_REVISION_STRING.

After this change, we no longer compute the (now-unused) values
of these two variables.

Since this removes the only use of llvm/utils/GetRepositoryPath,
remove that too (it's redundant with the system added in r354605).

While here, also remove LLD_VERSION_MAJOR and LLD_VERSION_MINOR.
Their uses were removed in r285163.

Also remove LLD_VERSION from Version.inc which as far as I can
tell has been unused since the file was added in r219277.

No behavior change.

Differential Revision: https://reviews.llvm.org/D72803
2020-01-16 09:55:36 -05:00
Andrew Ng d36b2649e5 [ELF] Optimization to LinkerScript::computeInputSections NFC
Moved the section name check ahead of any filename matching or
exclusion. Firstly, this reduces the need to retrieve the filename and
secondly, reduces the amount of potentially expensive filename pattern
matching if such rules are present in the linker script.

The impact of this change is particularly significant when linking
objects built with -ffunction-sections and -fstack-size-section, using a
linker script that includes non-trivial filename patterns. In a number
of such cases, the link time is halved.

Differential Revision: https://reviews.llvm.org/D72775
2020-01-16 13:56:02 +00:00
Yuanfang Chen 6e24c6037f Revert "[Support] make report_fatal_error `abort` instead of `exit`"
This reverts commit 647c3f4e47.

Got bots failure from sanitizer-windows and maybe others.
2020-01-15 17:52:25 -08:00
Yuanfang Chen 647c3f4e47 [Support] make report_fatal_error `abort` instead of `exit`
Summary:
This patch could be treated as a rebase of D33960. It also fixes PR35547.
A fix for `llvm/test/Other/close-stderr.ll` is proposed in D68164. Seems
the consensus is that the test is passing by chance and I'm not
sure how important it is for us. So it is removed like in D33960 for now.
The rest of the test fixes are just adding `--crash` flag to `not` tool.

** The reason it fixes PR35547 is

`exit` does cleanup including calling class destructor whereas `abort`
does not do any cleanup. In multithreading environment such as ThinLTO or JIT,
threads may share states which mostly are ManagedStatic<>. If faulting thread
tearing down a class when another thread is using it, there are chances of
memory corruption. This is bad 1. It will stop error reporting like pretty
stack printer; 2. The memory corruption is distracting and nondeterministic in
terms of error message, and corruption type (depending one the timing, it
could be double free, heap free after use, etc.).

Reviewers: rnk, chandlerc, zturner, sepavloff, MaskRay, espindola

Reviewed By: rnk, MaskRay

Subscribers: wuzish, jholewinski, qcolombet, dschuff, jyknight, emaste, sdardis, nemanjai, jvesely, nhaehnle, sbc100, arichardson, jgravelle-google, aheejin, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, jsji, lenary, s.egerton, pzheng, cfe-commits, MaskRay, filcab, davide, MatzeB, mehdi_amini, hiraditya, steven_wu, dexonsmith, rupprecht, seiya, llvm-commits

Tags: #llvm, #clang

Differential Revision: https://reviews.llvm.org/D67847
2020-01-15 17:05:13 -08:00
Reid Kleckner 8045a8a7f1 [COFF] Warn that LLD does not support /PDBSTRIPPED:
Doesn't really fix PR44491, but it avoids treating it as an input.
2020-01-15 15:11:19 -08:00
Alex Richardson 441410be47 [ELF] Avoid false-positive assert in getErrPlace()
This assertion was added as part of D70659 but did not account for .bss
input sections. I noticed that this assert was incorrectly triggering
while building FreeBSD for MIPS64. Fixed by relaxing the assert to also
account for SHT_NOBITS input sections and adjust the test
mips-jalr-non-function.s to link a file with a .bss section first.

Reviewed By: MaskRay, grimar
Differential Revision: https://reviews.llvm.org/D72567
2020-01-15 14:32:25 +00:00
Hans Wennborg 5852475e2c Bump the trunk major version to 11
and clear the release notes.
2020-01-15 13:38:01 +01:00
Igor Kudrin fcc08aa835 [MachO] Add a test for detecting reserved unit length.
This is a follow-up for D71546 to add a corresponding unit test.

Differential Revision: https://reviews.llvm.org/D72695
2020-01-15 16:55:11 +07:00
Fangrui Song bec1b55c64 [ELF] Delete the RelExpr member R_HINT. NFC
R_HINT is ignored like R_NONE. There are no strong reasons to keep
R_HINT. The largest RelExpr member R_RISCV_PC_INDIRECT is 60 now.

Differential Revision: https://reviews.llvm.org/D71822
2020-01-14 10:56:53 -08:00
Fangrui Song 40c5bd4212 [ELF] --exclude-libs: don't assign VER_NDX_LOCAL to undefined symbols
Suggested by Peter Collingbourne.

Non-VER_NDX_GLOBAL versions should not be assigned to defined symbols. --exclude-libs violates this and can cause a spurious error "cannot refer to absolute symbol" after D71795.

excludeLibs incorrectly assigns VER_NDX_LOCAL to an undefined weak symbol =>
isPreemptible is false =>
R_PLT_PC is optimized to R_PC =>
in isStaticLinkTimeConstant, an error is emitted.

Reviewed By: pcc, grimar

Differential Revision: https://reviews.llvm.org/D72681
2020-01-14 10:12:28 -08:00
Fangrui Song d9819f3662 [ELF] Delete unintended --force-bti 2020-01-13 23:57:00 -08:00
Fangrui Song 7cd429f27d [ELF] Add -z force-ibt and -z shstk for Intel Control-flow Enforcement Technology
This patch is a joint work by Rui Ueyama and me based on D58102 by Xiang Zhang.

It adds Intel CET (Control-flow Enforcement Technology) support to lld.
The implementation follows the draft version of psABI which you can
download from https://github.com/hjl-tools/x86-psABI/wiki/X86-psABI.

CET introduces a new restriction on indirect jump instructions so that
you can limit the places to which you can jump to using indirect jumps.

In order to use the feature, you need to compile source files with
-fcf-protection=full.

* IBT is enabled if all input files are compiled with the flag. To force enabling ibt, pass -z force-ibt.
* SHSTK is enabled if all input files are compiled with the flag, or if -z shstk is specified.

IBT-enabled executables/shared objects have two PLT sections, ".plt" and
".plt.sec".  For the details as to why we have two sections, please read
the comments.

Reviewed By: xiangzhangllvm

Differential Revision: https://reviews.llvm.org/D59780
2020-01-13 23:39:28 -08:00
Alex Richardson 894f742acb [MIPS][ELF] Use PC-relative relocations in .eh_frame when possible
When compiling position-independent executables, we now use
DW_EH_PE_pcrel | DW_EH_PE_sdata4. However, the MIPS ABI does not define a
64-bit PC-relative ELF relocation so we cannot use sdata8 for the large
code model case. When using the large code model, we fall back to the
previous behaviour of generating absolute relocations.

With this change clang-generated .o files can be linked by LLD without
having to pass -Wl,-z,notext (which creates text relocations).
This is simpler than the approach used by ld.bfd, which rewrites the
.eh_frame section to convert absolute relocations into relative references.

I saw in D13104 that apparently ld.bfd did not accept pc-relative relocations
for MIPS ouput at some point. However, I also checked that recent ld.bfd
can process the clang-generated .o files so this no longer seems true.

Reviewed By: atanasyan
Differential Revision: https://reviews.llvm.org/D72228
2020-01-13 14:14:03 +00:00
Fangrui Song 2bfee35cb8 [MC][ELF] Emit a relocation if target is defined in the same section and is non-local
For a target symbol defined in the same section, currently we don't emit
a relocation if VariantKind is VK_None (with few exceptions like RISC-V
relaxation), while GNU as emits one. This causes program behavior
differences with and without -ffunction-sections, and can break intended
symbol interposition in a -shared link.

```
.globl foo
foo:
  call foo      # no relocation. On other targets, may be written as b foo, etc
  call bar      # a relocation if bar is in another section (e.g. -ffunction-sections)
  call foo@plt  # a relocation
```

Unify these cases by always emitting a relocation. If we ever want to
optimize `call foo` in -shared links, we should emit a STB_LOCAL alias
and call via the alias.

ARM/thumb2-beq-fixup.s: we now emit a relocation to global_thumb_fn as GNU as does.
X86/Inputs/align-branch-64-2.s: we now emit R_X86_64_PLT32 to foo as GNU does.

ELF/relax.s: rewrite the test as target-in-same-section.s .
We omitted relocations to `global` and now emit R_X86_64_PLT32.
Note, GNU as does not emit a relocation for `jmp global` (maybe its own
bug). Our new behavior is compatible except `jmp global`.

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D72197
2020-01-12 13:46:24 -08:00
Tom Tan 7c81649219 [COFF] Align ARM64 range extension thunks at instruction boundary
RangeExtensionThunkARM64 is created for out-of-range branches on Windows ARM64
because branch instructions has limited bits to encode target address.
Currently, RangeExtensionThunkARM64 is appended to its referencing COFF section
from object file at link time without any alignment requirement, so if size of
the preceding COFF section is not aligned to instruction boundary (4 bytes),
RangeExtensionThunkARM64 will emit thunk instructions at unaligned address
which is never a valid branch target on ARM64, and usually triggers invalid
instruction exception when branching to it.

This PR fixes it by requiring such thunks to align at 4 bytes.

Differential revision: https://reviews.llvm.org/D72473
2020-01-10 19:03:17 -08:00
Sam Clegg 9cd985815a [lld][WebAssembly] Add libcall symbols to the link when LTO is being used.
This code is copied almost verbatim from the equivalent change to the
ELF linker:

- https://reviews.llvm.org/D50017
- https://reviews.llvm.org/D50475

The upshot is that libraries containing libcall (such as compiler-rt
and libc) can be compiled with LTO.

Fixes PR41384

Differential Revision: https://reviews.llvm.org/D71738
2020-01-10 11:01:05 -08:00
Fangrui Song 2d077d6dfa [ELF] Make TargetInfo::writeIgotPlt a no-op
RELA targets don't read initial .got.plt entries.
REL targets (ARM, x86-32) write the address of the IFUNC resolver to the
entry (`write32le(buf, s.getVA())`).

The default writeIgotPlt() is not meaningful. Make it a no-op. AArch64
and x86-64 will have 0 as initial .got.plt entries associated with
IFUNC.

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D72474
2020-01-10 09:59:22 -08:00
James Henderson 6e3ca962fa [DebugInfo] Improve error message text
Unlike most of our errors in the debug line parser, the "no end of
sequence" message was missing any reference to which line table it
refererred to. This change adds the offset to this message.

Reviewed by: dblaikie

Differential Revision: https://reviews.llvm.org/D72443
2020-01-10 14:59:58 +00:00
Andrew Ng 564481aebe [Support] ThreadPoolExecutor fixes for Windows/MinGW
Changed ThreadPoolExecutor to no longer use detached threads and instead
to join threads on destruction. This is to prevent intermittent crashing
on Windows when doing a normal full exit, e.g. via exit().

Changed ThreadPoolExecutor to be a ManagedStatic so that it can be
stopped on llvm_shutdown(). Without this, it would only be stopped in
the destructor when doing a full exit. This is required to avoid
intermittent crashing on Windows due to a race condition between the
ThreadPoolExecutor starting up threads and the process doing a fast
exit, e.g. via _exit().

The Windows crashes appear to only occur with the MSVC static runtimes
and are more frequent with the debug static runtime.

These changes also prevent intermittent deadlocks on exit with the MinGW
runtime.

Differential Revision: https://reviews.llvm.org/D70447
2020-01-10 12:44:01 +00:00
Wei Mi 21a4710c67 [ThinLTO] Pass CodeGenOpts like UnrollLoops/VectorizeLoop/VectorizeSLP
down to pass builder in ltobackend.

Currently CodeGenOpts like UnrollLoops/VectorizeLoop/VectorizeSLP in clang
are not passed down to pass builder in ltobackend when new pass manager is
used. This is inconsistent with the behavior when new pass manager is used
and thinlto is not used. Such inconsistency causes slp vectorization pass
not being enabled in ltobackend for O3 + thinlto right now. This patch
fixes that.

Differential Revision: https://reviews.llvm.org/D72386
2020-01-09 21:13:11 -08:00
Nico Weber efabe427b2 fix a few typos to cycle the bots 2020-01-09 23:10:15 -05:00
Fangrui Song 375371cc8b [ELF] Fix includeInDynsym() when an undefined weak is merged with a lazy definition
An undefined weak does not fetch the lazy definition. A lazy weak symbol
should be considered undefined, and thus preemptible if .dynsym exists.

D71795 is not quite an NFC. It errors on an R_X86_64_PLT32 referencing
an undefined weak symbol. isPreemptible is false (incorrect) => R_PLT_PC
is optimized to R_PC => in isStaticLinkTimeConstant, an error is emitted
when an R_PC is applied on an undefined weak (considered absolute).
2020-01-09 16:24:02 -08:00
Alex Richardson 1444e6e2e6 Re-apply "[ELF] Allow getErrPlace() to work before Out::bufferStart is set"
This time with a fix for the UBSAN failure.

Differential Revision: https://reviews.llvm.org/D70659
2020-01-09 20:26:31 +00:00
Sid Manning 0fa8f701cc [ELF][Hexagon] Add support for IE relocations
Differential Revision: https://reviews.llvm.org/D71143
2020-01-09 09:45:24 -06:00
Martin Storsjö 78ce19b7e1 [LLD] [COFF] Fix post-commit suggestions for absolute symbol equality
Differential Revision: https://reviews.llvm.org/D72252
2020-01-08 22:10:05 +02:00
Fangrui Song b841e119d7 [ELF] Delete an unused special rule from isStaticLinkTimeConstant. NFC
Weak undefined symbols are preemptible after D71794.

  if (sym.isPreemptible)
    return false;
  if (!config->isPic)
    return true;
  // isPic means includeInDynsym is true after D71794.

  ...

  // We can delete this if because it can never be true.
  if (sym.isUndefWeak)
    return true;

Differential Revision: https://reviews.llvm.org/D71795
2020-01-08 09:41:59 -08:00
Fangrui Song 96e2376d02 [ELF] Don't special case weak symbols for pie with no shared objects
D59275 added the following clause to Symbol::includeInDynsym()

  if (isUndefWeak() && Config->Pie && SharedFiles.empty())
    return false;

D59549 explored the possibility to generalize it for -no-pie.

GNU ld's rules are architecture dependent and partly controlled by -z
{,no-}dynamic-undefined-weak. Our attempts to mimic its rules are
actually half-baked and don't provide perceivable benefits (it can save
a few more weak undefined symbols in .dynsym in a -static-pie
executable). Let's just delete the rule for simplicity. We will expect
cosmetic inconsistencies with ld.bfd in certain -static-pie scenarios.

This permits a simplification in D71795.

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D71794
2020-01-08 09:38:49 -08:00
Peter Smith 051c4d5b7b [LLD][ELF][AArch64] Do not use thunk for undefined weak symbol.
In AArch64 a branch to an undefined weak symbol that does not have a PLT
entry should resolve to the next instruction. The thunk generation code
can prevent this from happening as a range extension thunk can be generated
if the branch is sufficiently far away from 0, the value of an undefined
weak symbol.

The fix is taken from the Arm implementation of needsThunk(), we prevent a
thunk from being generated to an undefined weak symbol.

fixes pr44451

Differential Revision: https://reviews.llvm.org/D72267
2020-01-07 09:57:51 +00:00
Kazuaki Ishizaki 7ae3d33546 [lld] Fix trivial typos in comments
Reviewed By: ruiu, MaskRay

Differential Revision: https://reviews.llvm.org/D72196
2020-01-06 10:25:48 -08:00
Fangrui Song 896b84ac2c [llvm-readelf] Print EI_ABIVERSION as decimal instead of hexadecimal
This matches GNU readelf and llvm-readobj.

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D72234
2020-01-06 09:25:45 -08:00
Fangrui Song 085898d469 [ELF] Drop const qualifier to fix -Wrange-loop-analysis. NFC
```
lld/ELF/Relocations.cpp:1622:56: warning: loop variable 'ts' of type 'const std::pair<ThunkSection *, uint32_t>' (aka 'const pair<lld:🧝:ThunkSection *, unsigned int>') creates a copy from type 'const std::pair<ThunkSection *, uint32_t>' [-Wrange-loop-analysis]
        for (const std::pair<ThunkSection *, uint32_t> ts : isd->thunkSections)
```

Drop const qualifier to fix -Wrange-loop-analysis.
We can make -Wrange-loop-analysis warnings (DiagnoseForRangeConstVariableCopies) on `const A` more
permissive on more types (e.g. POD -> trivially copyable), unfortunately it will not make std::pair
good, because `constexpr pair& operator=(const pair& p);` is unfortunately user-defined.

Reviewed By: Mordante

Differential Revision: https://reviews.llvm.org/D72211
2020-01-04 12:24:39 -08:00
Martin Storsjö 1737cc750c [LLD] [COFF] Don't error out on duplicate absolute symbols with the same value
Both MS link.exe and GNU ld.bfd handle it this way; one can have
multiple object files defining the same absolute symbols, as long
as it defines it to the same value. But if there are multiple absolute
symbols with differing values, it is treated as an error.

Differential Revision: https://reviews.llvm.org/D71981
2020-01-04 12:29:33 +02:00
James Henderson cc6be11872 [test][ELF] Use CHECK-NEXT to properly verify error messages
Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D72092
2020-01-03 12:38:09 +00:00
Reid Kleckner 783db78835 [PDB] Print the most redundant type record indices with /summary
Summary:
I used this information to motivate splitting up the Intrinsic::ID enum
(5d986953c8) and adding a key method to
clang::Sema (586f65d31f) which saved a
fair amount of object file size.

Example output for clang.pdb:

  Top 10 types responsible for the most TPI input bytes:
         index     total bytes   count     size
        0x3890:      8,671,220 = 1,805 *  4,804
       0xE13BE:      5,634,720 =   252 * 22,360
       0x6874C:      5,181,600 =   408 * 12,700
        0x2A1F:      4,520,528 = 1,574 *  2,872
       0x64BFF:      4,024,020 =   469 *  8,580
        0x1123:      4,012,020 = 2,157 *  1,860
        0x6952:      3,753,792 =   912 *  4,116
        0xC16F:      3,630,888 =   633 *  5,736
        0x69DD:      3,601,160 =   985 *  3,656
        0x678D:      3,577,904 =   319 * 11,216

In this case, we can see that record 0x3890 is responsible for ~8MB of
total object file size for objects in clang.

The user can then use llvm-pdbutil to find out what the record is:

  $ llvm-pdbutil dump -types -type-index 0x3890
                       Types (TPI Stream)
  ============================================================
    Showing 1 records.
       0x3890 | LF_FIELDLIST [size = 4804]
                - LF_STMEMBER [name = `WORDTYPE_MAX`, type = 0x1001, attrs = public]
                - LF_MEMBER [name = `U`, Type = 0x37F0, offset = 0, attrs = private]
                - LF_MEMBER [name = `BitWidth`, Type = 0x0075 (unsigned), offset = 8, attrs = private]
                - LF_METHOD [name = `APInt`, # overloads = 8, overload list = 0x3805]
  ...

In this case, we can see that these are members of the APInt class,
which is emitted in 1805 object files.

The next largest type is ASTContext:

  $ llvm-pdbutil dump -types -type-index 0xE13BE bin/clang.pdb
      0xE13BE | LF_FIELDLIST [size = 22360]
                - LF_BCLASS
                  type = 0x653EA, offset = 0, attrs = public
                - LF_MEMBER [name = `Types`, Type = 0x653EB, offset = 8, attrs = private]
                - LF_MEMBER [name = `ExtQualNodes`, Type = 0x653EC, offset = 24, attrs = private]
                - LF_MEMBER [name = `ComplexTypes`, Type = 0x653ED, offset = 48, attrs = private]
                - LF_MEMBER [name = `PointerTypes`, Type = 0x653EE, offset = 72, attrs = private]
  ...

ASTContext only appears 252 times, but the list of members is long, and
must be repeated everywhere it is used.

This was the output before I split Intrinsic::ID:

  Top 10 types responsible for the most TPI input:
        0x686C:     69,823,920 = 1,070 * 65,256
        0x686D:     69,819,640 = 1,070 * 65,252
        0x686E:     69,819,640 = 1,070 * 65,252
        0x686B:     16,371,000 = 1,070 * 15,300
        ...

These records were all lists of intrinsic enums.

Reviewers: MaskRay, ruiu

Subscribers: mgrang, zturner, thakis, hans, akhuang, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71437
2020-01-02 16:10:36 -08:00
Saleem Abdulrasool abb0075306 build: reduce CMake handling for zlib
Rather than handling zlib handling manually, use `find_package` from CMake
to find zlib properly. Use this to normalize the `LLVM_ENABLE_ZLIB`,
`HAVE_ZLIB`, `HAVE_ZLIB_H`. Furthermore, require zlib if `LLVM_ENABLE_ZLIB` is
set to `YES`, which requires the distributor to explicitly select whether
zlib is enabled or not. This simplifies the CMake handling and usage in
the rest of the tooling.

This restores 68a235d07f,
e6c7ed6d21.  The problem with the windows
bot is a need for clearing the cache.
2020-01-02 11:19:12 -08:00
Fangrui Song 838f53ed4d [ELF][Hexagon][test] Use llvm-readobj to check relocations. NFC
Reviewed By: sidneym

Differential Revision: https://reviews.llvm.org/D72093
2020-01-02 11:06:16 -08:00
Sid Manning 81ffe89735 Add TPREL relocation support to Hexagon
Differential Revision: https://reviews.llvm.org/D71069
2020-01-02 11:18:26 -06:00
James Henderson 3aeb741535 [test][ELF] Verify debug line corruption messages are printed once
LLD warns if it encounters malformed debug data when parsing line
information for an undefined reference. We only want to warn once.

This patch adds additional checking to make sure the warnings are
printed only once, both for variables within the same program and
variables in later line programs.

Reviewed by: grimar, MaskRay

Differential Revision: https://reviews.llvm.org/D71759
2020-01-02 17:16:18 +00:00
James Henderson e406cca5f9 Revert "build: reduce CMake handling for zlib"
This reverts commit 68a235d07f.

This commit broke the clang-x64-windows-msvc build bot and a follow-up
commit did not fix it. Reverting to fix the bot.
2020-01-02 16:02:10 +00:00
Saleem Abdulrasool 68a235d07f build: reduce CMake handling for zlib
Rather than handling zlib handling manually, use `find_package` from CMake
to find zlib properly. Use this to normalize the `LLVM_ENABLE_ZLIB`,
`HAVE_ZLIB`, `HAVE_ZLIB_H`. Furthermore, require zlib if `LLVM_ENABLE_ZLIB` is
set to `YES`, which requires the distributor to explicitly select whether
zlib is enabled or not. This simplifies the CMake handling and usage in
the rest of the tooling.
2020-01-01 16:36:59 -08:00
Fangrui Song 681b1be774 [lld] Fix -Wrange-loop-analysis warnings
One instance looks like a false positive:

lld/ELF/Relocations.cpp:1622:14: note: use reference type 'const std::pair<ThunkSection *, uint32_t> &' (aka 'cons
t pair<lld:🧝:ThunkSection *, unsigned int> &') to prevent copying
        for (const std::pair<ThunkSection *, uint32_t> ts : isd->thunkSections)

It is not changed in this commit.
2020-01-01 15:41:20 -08:00
Fangrui Song 47e3d3ec0c [ELF][RISCV][test] Test absolute/PC-relative/branch relocations to undefined weak symbols 2019-12-31 23:58:11 -08:00
Fangrui Song e3e13db714 [ELF][RISCV] Improve error message for unknown relocations
Like rLLD354040.
2019-12-31 16:09:55 -08:00
Fangrui Song bb87364f26 [ELF][PPC64] Improve "call lacks nop" diagnostic and make it compatible with GCC<5.5 and GCC<6.4
GCC before r245813 (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79439)
did not emit nop after b/bl. This can happen with recursive calls.
r245813 was back ported to GCC 5.5 and GCC 6.4.

This is common, for example, libstdc++.a(locale.o) shipped with GCC 4.9
and many objects in netlib lapack can cause lld to error.  gold allows
such calls to the same section. Our __plt_foo symbol's `section` field
is used for ThunkSection, so we can't implement a similar loosen rule
easily. But we can make use of its `file` field which is currently NULL.

Differential Revision: https://reviews.llvm.org/D71639
2019-12-29 23:05:11 -08:00
Fangrui Song fb2944bd7f [ELF][PPC32] Implement IPLT code sequence for non-preemptible IFUNC
Similar to D71509 (EM_PPC64), on EM_PPC, the IPLT code sequence should
be similar to a PLT call stub. Unlike EM_PPC64, EM_PPC -msecure-plt has
small/large PIC model differences.

* -fpic/-fpie: R_PPC_PLTREL24 r_addend=0.  The call stub loads an address relative to `_GLOBAL_OFFSET_TABLE_`.
* -fPIC/-fPIE: R_PPC_PLTREL24 r_addend=0x8000. (A partial linked object
  file may have an addend larger than 0x8000.) The call stub loads an address relative to .got2+0x8000.

Just assume large PIC model for now. This patch makes:

  // clang -fuse-ld=lld -msecure-plt -fno-pie -no-pie a.c
  // clang -fuse-ld=lld -msecure-plt -fPIE -pie a.c
  #include <stdio.h>
  static void impl(void) { puts("meow"); }
  void thefunc(void) __attribute__((ifunc("resolver")));
  void *resolver(void) { return &impl; }
  int main(void) {
    thefunc();
    void (*theptr)(void) = &thefunc;
    theptr();
  }

work on Linux glibc. -fpie will crash because the compiler and the
linker do not agree on the value which r30 stores (_GLOBAL_OFFSET_TABLE_
vs .got2+0x8000).

Differential Revision: https://reviews.llvm.org/D71621
2019-12-29 22:42:53 -08:00
Fangrui Song 45acc35ac2 [ELF][PPC64] Implement IPLT code sequence for non-preemptible IFUNC
Non-preemptible IFUNC are placed in in.iplt (.glink on EM_PPC64).  If
there is a non-GOT non-PLT relocation, for pointer equality, we change
the type of the symbol from STT_IFUNC and STT_FUNC and bind it to the
.glink entry.

On EM_386, EM_X86_64, EM_ARM, and EM_AARCH64, the PLT code sequence
loads the address from its associated .got.plt slot. An IPLT also has an
associated .got.plt slot and can use the same code sequence.

On EM_PPC64, the PLT code sequence is actually a bl instruction in
.glink .  It jumps to `__glink_PLTresolve` (the PLT header). and
`__glink_PLTresolve` computes the .plt slot (relocated by
R_PPC64_JUMP_SLOT).

An IPLT does not have an associated R_PPC64_JUMP_SLOT, so we cannot use
`bl` in .iplt . Instead, create a call stub which has a similar code
sequence as PPC64PltCallStub. We don't save the TOC pointer, so such
scenarios will not work: a function pointer to a non-preemptible ifunc,
which resolves to a function defined in another DSO. This is the
restriction described by https://sourceware.org/glibc/wiki/GNU_IFUNC
(though on many architectures it works in practice):

  Requirement (a): Resolver must be defined in the same translation unit as the implementations.

If an ifunc is taken address but not called, technically we don't need
an entry for it, but we currently do that.

This patch makes

  // clang -fuse-ld=lld -fno-pie -no-pie a.c
  // clang -fuse-ld=lld -fPIE -pie a.c
  #include <stdio.h>
  static void impl(void) { puts("meow"); }
  void thefunc(void) __attribute__((ifunc("resolver")));
  void *resolver(void) { return &impl; }
  int main(void) {
    thefunc();
    void (*theptr)(void) = &thefunc;
    theptr();
  }

work on Linux glibc and FreeBSD. Calling a function pointer pointing to
a Non-preemptible IFUNC never worked before.

Differential Revision: https://reviews.llvm.org/D71509
2019-12-29 22:40:03 -08:00
David Blaikie 22f34c7f34 lld: Remove explicit copy ops from AssociatedIterator, relying on implicit operators 2019-12-27 17:27:20 -08:00
Fangrui Song dce7a362be [ELF] Improve the condition to create .interp
This restores commit 1417558e4a and its follow-up, reverted by commit c3dbd782f1.

After this commit:

clang -fuse-ld=bfd -no-pie -nostdlib a.c => .interp not created
clang -fuse-ld=bfd -pie -fPIE -nostdlib a.c => .interp created

clang -fuse-ld=gold -no-pie -nostdlib a.c => .interp not created
clang -fuse-ld=gold -pie -fPIE -nostdlib a.c => .interp created

clang -fuse-ld=lld -no-pie -nostdlib a.c => .interp created
clang -fuse-ld=lld -pie -fPIE -nostdlib a.c => .interp created
2019-12-27 15:34:25 -08:00
Reid Kleckner c3dbd782f1 Revert "[ELF] Improve the condition to create .interp"
This reverts commit 1417558e4a.
Also reverts commit 019a92bb28.

This causes check-sanitizer to fail. The "-Nolib" variant of the test
crashes on startup in the loader.
2019-12-27 13:05:41 -08:00
Fangrui Song 019a92bb28 [ELF][test] Fix dynamic-linker.s 2019-12-26 13:44:52 -08:00
Fangrui Song 1417558e4a [ELF] Improve the condition to create .interp
Similar to rL362355, but with the `!config->shared` guard.

(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
2019-12-26 13:26:43 -08:00
Fangrui Song 1edd965130 [ELF] Support input section description .gnu.version* in /DISCARD/
Linux powerpc discards `*(.gnu.version*)` (arch/powerpc/kernel/vmlinux.lds.S)
to suppress --orphan-handling=warn warnings in the -pie output `.tmp_vmlinux1`

The support is simple. Just add isLive() to:

1) Fix an assertion in SectionBase::getPartition() called by VersionTableSection::isNeeded().
2) Suppress DT_VERSYM, DT_VERDEF, DT_VERNEED and DT_VERNEEDNUM, if the relevant section is discarded.

Reviewed By: grimar

Differential Revision: https://reviews.llvm.org/D71819
2019-12-26 09:54:22 -08:00
Fangrui Song ba1cdba4c4 [llvm-nm] Display STT_GNU_IFUNC as 'i'
Reviewed By: grimar

Differential Revision: https://reviews.llvm.org/D71803
2019-12-25 09:47:53 -08:00
Fangrui Song a36ddf0aa9 Migrate function attribute "no-frame-pointer-elim"="false" to "frame-pointer"="none" as cleanups after D56351 2019-12-24 16:27:51 -08:00
Fangrui Song 502a77f125 Migrate function attribute "no-frame-pointer-elim" to "frame-pointer"="all" as cleanups after D56351 2019-12-24 15:57:33 -08:00
Fangrui Song 261b7b4a6b [ELF] Don't suggest an alternative spelling for a symbol in a discarded section
For undef-not-suggest.test, we currently make redundant alternative
spelling suggestions:

```
ld.lld: error: relocation refers to a discarded section: .text.foo
>>> defined in a.o
>>> section group signature: foo
>>> prevailing definition is in a.o
>>> referenced by a.o:(.rodata+0x0)
>>> did you mean:
>>> defined in: a.o

ld.lld: error: relocation refers to a symbol in a discarded section: foo
>>> defined in a.o
>>> section group signature: foo
>>> prevailing definition is in a.o
>>> referenced by a.o:(.rodata+0x8)
>>> did you mean: for
>>> defined in: a.o
```

Reviewed By: grimar, ruiu

Differential Revision: https://reviews.llvm.org/D71735
2019-12-23 09:10:29 -08:00
Fangrui Song 2539cd22e9 [ELF] Delete a redundant R_HINT check from isStaticLinkTimeConstant(). NFC
scanReloc() returns when it sees an R_HINT.
2019-12-22 16:58:22 -08:00
John Baldwin 189b7393d5 [lld][RISCV] Use an e_flags of 0 if there are only binary input files.
Summary:
If none of the input files are ELF object files (for example, when
generating an object file from a single binary input file via
"-b binary"), use a fallback value for the ELF header flags instead
of crashing with an assertion failure.

Reviewers: MaskRay, ruiu, espindola

Reviewed By: MaskRay, ruiu

Subscribers: kevans, grimar, emaste, arichardson, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, kito-cheng, shiva0217, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, rkruppe, PkmX, jocewei, psnobl, benna, Jim, lenary, s.egerton, pzheng, sameer.abuasal, apazos, luismarques, llvm-commits, jrtc27

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71101
2019-12-21 17:59:37 +00:00
Nico Weber bad8f3957e hopefully last doc typo fix to cycle bots 2019-12-20 22:28:21 -05:00
Nico Weber 9293da6ac5 fix yet another doc typo to cycle bots 2019-12-20 22:25:14 -05:00
Martin Storsjö 29d8c27c65 [LLD] [COFF] Fix reporting duplicate errors for absolute symbols
Previously this caused crashes in the reportDuplicate method.

A DefinedAbsolute doesn't have any InputFile attached to it, so we
can't report the file for the original symbol.

We could add an InputFile argument to SymbolTable::addAbsolute
only for the sake of error reporting, but even then it'd be assymetrical,
only pointing out the file containing the new conflicting definition,
not the original one.

Differential Revision: https://reviews.llvm.org/D71679
2019-12-19 12:14:08 +02:00
Fangrui Song 37b2808059 [ELF] writePlt, writeIplt: replace parameters gotPltEntryAddr and index with `const Symbol &`. NFC
PPC::writeIplt (IPLT code sequence, D71621) needs to access `Symbol`.

Reviewed By: grimar, ruiu

Differential Revision: https://reviews.llvm.org/D71631
2019-12-18 00:14:03 -08:00
Fangrui Song 07522e4e23 [ELF] Fix a comment. NFC 2019-12-17 17:17:33 -08:00
Fangrui Song 345f59667d [ELF] Rename .plt to .iplt and decrease EM_PPC{,64} alignment of .glink to 4
GNU ld creates the synthetic section .iplt, and has a built-in linker
script that assigns .iplt to the output section .plt . There is no
output section named .iplt .

Making .iplt an output section actually has a benefit that makes the
tricky toolchain feature stand out. Symbolizers don't have to deal with
mixed PLT entries (e.g. llvm-objdump -d incorrectly annotates such jump
targets).

On EM_PPC{,64}, .glink contains a PLT resolver and a series of jump
instructions. The 4-byte entry size makes it unnecessary to have an
alignment of 16.

Mark ppc32-gnu-ifunc.s and ppc32-gnu-ifunc-nonpreemptable.s as `XFAIL: *`.
They test IPLT on EM_PPC, which never works.

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D71520
2019-12-17 00:15:59 -08:00
Fangrui Song 891a8655ab [ELF] Add IpltSection
PltSection is used by both PLT and IPLT. The PLT section may have a
header while the IPLT section does not. Split off IpltSection from
PltSection to be clearer.

Unlike other targets, PPC64 cannot use the same code sequence for PLT
and IPLT. This helps make a future PPC64 patch (D71509) more isolated.

On EM_386 and EM_X86_64, when PLT is empty while IPLT is not, currently
we are inconsistent whether the PLT header is conceptually attached to
in.plt or in.iplt .  Consistently attach the header to in.plt can make
the -z retpolineplt logic simpler. It also makes `jmp` point to an
aesthetically better place for non-retpolineplt cases.

Reviewed By: grimar, ruiu

Differential Revision: https://reviews.llvm.org/D71519
2019-12-17 00:06:04 -08:00
Igor Kudrin 5279f96577 [MachO] Fix detecting malformed DWARF.
This fixes an invalid constant used to detect the reserved range when
reading the compilation unit header. See also: D64622 and D65039.

Differential Revision: https://reviews.llvm.org/D71546
2019-12-17 15:03:23 +07:00
Fangrui Song ee912fe6a1 [ELF] Delete unused declaration addIRelativeRelocs after D65995. NFC 2019-12-16 11:19:22 -08:00
Fangrui Song 90d195d026 [ELF] Delete relOff from TargetInfo::writePLT
This change only affects EM_386. relOff can be computed from `index`
easily, so it is unnecessarily passed as a parameter.

Both in.plt and in.iplt entries are written by writePLT. For in.iplt,
the instruction `push reloc_offset` will change because `index` is now
different. Fortunately, this does not matter because `push; jmp` is only
used by PLT. IPLT does not need the code sequence.

Reviewed By: grimar, ruiu

Differential Revision: https://reviews.llvm.org/D71518
2019-12-16 11:10:02 -08:00
Fangrui Song 98afa2c1f1 [ELF] De-template PltSection::addEntry. NFC 2019-12-16 11:03:20 -08:00
Fangrui Song f036f1cc85 [ELF] Delete redundant isLive() check. NFC 2019-12-15 21:59:55 -08:00
Vlad Tsyrklevich 17063abd1e Revert "[ELF] Allow getErrPlace() to work before Out::bufferStart is set"
This reverts commit 2bbd32f5e8, it was
causing UBSan failures like the following:
lld/ELF/Target.cpp:103:41: runtime error: applying non-zero offset 24 to null pointer
2019-12-13 09:43:51 -08:00
Fangrui Song 69d10d282e [ELF] Update st_size when merging a common symbol with a shared symbol
When a common symbol is merged with a shared symbol, increase st_size if
the shared symbol has a larger st_size. At runtime, the executable's
symbol overrides the shared symbol.  The shared symbol may be created
from common symbols in a previous link.  This rule makes sure we pick
the largest size among all common symbols.

This behavior matches GNU ld. See
https://sourceware.org/bugzilla/show_bug.cgi?id=25236 for discussions.

A shared symbol does not hold alignment constraints. Ignore the
alignment update.

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D71161
2019-12-13 09:23:36 -08:00
Alex Richardson 2bbd32f5e8 [ELF] Allow getErrPlace() to work before Out::bufferStart is set
Summary:
So far it seems like the only test affected by this change is the one I
recently added for R_MIPS_JALR relocations since the other test cases that
use this function early (unknown-relocation-*) do not have a valid input
section for the relocation offset.

Reviewers: ruiu, grimar, MaskRay, espindola

Reviewed By: ruiu, MaskRay

Subscribers: emaste, sdardis, jrtc27, atanasyan, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70659
2019-12-13 12:19:55 +00:00
Rui Ueyama 69da7e29de Revert an accidental commit af5ca40b47 2019-12-13 15:17:40 +09:00
Rui Ueyama 6faf8bdcc4 Update the man page
Add a description about the compression level of the debug info.

Differential Revision: https://reviews.llvm.org/D71385
2019-12-13 15:15:00 +09:00
Rui Ueyama af5ca40b47 temporary 2019-12-13 14:35:03 +09:00
Fangrui Song ba8149e27d [ELF] Add a comment to handleSectionGroup(). NFC
Apply suggestion in https://reviews.llvm.org/D71157#1780834

Reviewed By: grimar, ruiu

Differential Revision: https://reviews.llvm.org/D71388
2019-12-12 09:23:59 -08:00
Sam Clegg 881d877846 [WebAssembly] Add new `export_name` clang attribute for controlling wasm export names
This is equivalent to the existing `import_name` and `import_module`
attributes which control the import names in the final wasm binary
produced by lld.

This maps the existing

This attribute currently requires a string rather than using the
symbol name for a couple of reasons:

1. Avoid confusion with static and dynamic linking which is
   based on symbol name.  Exporting a function from a wasm module using
   this directive is orthogonal to both static and dynamic linking.
2. Avoids name mangling.

Differential Revision: https://reviews.llvm.org/D70520
2019-12-11 11:54:57 -08:00
Fangrui Song 5a3a9e9927 [ELF][AArch64] Rename --force-bti to -z force-bti and --pac-plt to -z pac-plt
Summary:
The original design used --foo but the upstream complained that ELF only
options should be -z foo. See https://sourceware.org/ml/binutils/2019-04/msg00151.html
https://sourceware.org/git/?p=binutils-gdb.git;a=commitdiff;h=8bf6d176b0a442a8091d338d4af971591d19922c
made the rename.

Our --force-bti and --pac-plt implement the same functionality, so it
seems wise to be consistent with GNU ld.

Reviewed By: peter.smith

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71327
2019-12-11 09:26:32 -08:00
Peter Smith 86d24193a9 [LLD][ELF][AArch64][ARM] When errata patching, round thunk size to 4KiB.
On some edge cases such as Chromium compiled with full instrumentation we
have a .text section over twice the size of the maximum branch range and
the instrumented code generation containing many examples of the erratum
sequence. The combination of Thunks and many erratum sequences causes
finalizeAddressDependentContent() to not converge. We end up with:
start
- Thunk Creation (disturbs addresses after thunks, creating more patches)
- Patch Creation (disturbs addresses after patches, creating more thunks)
- goto start

In most images with few thunks and patches the mutual disturbance does not
cause convergence problems. As the .text size and number of patches go up
the risk increases.

A way to prevent the thunk creation from interfering with patch creation is
to round up the size of the thunks to a 4KiB boundary when the
erratum patch is enabled. As the erratum sequence only triggers when an
instruction sequence starts at 0xff8 or 0xffc modulo (4 KiB) by making the
thunks not affect addresses modulo (4 KiB) we prevent thunks from
interfering with the patch.

The patches themselves could be aggregated in the same way that Thunks are
within ThunkSections and we could round up the size in the same way. This
would reduce the number of patches created in a .text section size >
128 MiB but would not likely help convergence problems.

Differential Revision: https://reviews.llvm.org/D71281

fixes (remaining part of) pr44071, other part in D71242
2019-12-11 14:09:15 +00:00
Peter Smith 247b2ce11c [LLD][ELF][AArch64][ARM] Add missing classof to patch sections.
The code to insert patch section merges them with a comparison function that
uses logic of the form:
return (isa<PatchSection>(a) && !isa<PatchSection>(b));
If the PatchSections don't implement classof this check fails if b is also
a SyntheticSection. This can result in the patches being out of range if
the SyntheticSection is big, for example a ThunkSection with lots of thunks.

Differential Revision: https://reviews.llvm.org/D71242

fixes (part of) pr44071
2019-12-11 14:09:15 +00:00
Fangrui Song 6e513a5382 [ELF] Move a computeIsPreemptible() pass into ICF. NFC
Address post-commit review for D71163.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D71326
2019-12-10 22:21:05 -08:00
Fangrui Song cd0ab2428f [ELF] --icf: do not fold preemptible symbols
Fixes PR44124.

A preemptible symbol may refer to a different definition at runtime.
When comparing a pair of relocations, if they refer to different
symbols, and either symbol is preemptible, the two containing sections
should be considered different.

gold has a similar rule https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commit;h=ce97fa81e0c46d216b80b143ad8c02fff6906fef

Reviewed By: grimar

Differential Revision: https://reviews.llvm.org/D71163
2019-12-10 09:06:08 -08:00
Fangrui Song 60ce444eaa [ELF] Refine section group --gc-sections rules to not discard .debug_types
clang/gcc -fdebug-type-sections places .debug_types and
.rela.debug_types in a section group, with a signature symbol which
represents the type signature. The section group is for deduplication
purposes.

After D70146, we will discard such section groups. Refine the rule so
that we will retain the group if no member has the SHF_ALLOC flag.

GNU ld has a similar rule to retain the group if all members have the
SEC_DEBUGGING flag. We try to be more general for future-proof purposes:
if other non-SHF_ALLOC sections have deduplication needs, they may be
placed in a section group. Don't discard them.

Reviewed By: grimar

Differential Revision: https://reviews.llvm.org/D71157
2019-12-10 09:00:58 -08:00
Sam Clegg b4f4e370b5 [WebAssebmly][MC] Support .import_name/.import_field asm directives
Convert the MC test to use asm rather than bitcode.

This is a precursor to https://reviews.llvm.org/D70520.

Differential Revision: https://reviews.llvm.org/D70877
2019-12-06 15:09:56 -08:00
Fangrui Song c8f0d3e130 [ELF][PPC64] Support long branch thunks with addends
Fixes PPC64 part of PR40438

  // clang -target ppc64le -c a.cc
  // .text.unlikely may be placed in a separate output section (via -z keep-text-section-prefix)
  // The distance between bar in .text.unlikely and foo in .text may be larger than 32MiB.
  static void foo() {}
  __attribute__((section(".text.unlikely"))) static int bar() { foo(); return 0; }
  __attribute__((used)) static int dummy = bar();

This patch makes such thunks with addends work for PPC64.

AArch64: .text -> `__AArch64ADRPThunk_ (adrp x16, ...; add x16, x16, ...; br x16)` -> target
PPC64: .text -> `__long_branch_ (addis 12, 2, ...; ld 12, ...(12); mtctr 12; bctr)` -> target

AArch64 can leverage ADRP to jump to the target directly, but PPC64
needs to load an address from .branch_lt . Before Power ISA v3.0, the
PC-relative ADDPCIS was not available. .branch_lt was invented to work
around the limitation.

Symbol::ppc64BranchltIndex is replaced by
PPC64LongBranchTargetSection::entry_index which take addends into
consideration.

The tests are rewritten: ppc64-long-branch.s tests -no-pie and
ppc64-long-branch-pi.s tests -pie and -shared.

Reviewed By: sfertile

Differential Revision: https://reviews.llvm.org/D70937
2019-12-05 10:17:45 -08:00
Fangrui Song 944f109ad7 [ELF][PPC64] Don't copy ppc64BranchltIndex in replaceWithDefined
replaceWithDefined is used by canonical PLT and copy relocations, which
imply that the symbol is preemptable. ppc64BranchltIndex is only used by
non-preemptable cases, and it can only be the default value in
replaceWithDefined.
2019-12-05 09:33:30 -08:00
Peter Smith 784f57584f [LLD][ELF][AArch64] .note.gnu.property sections should have alignment 8
The .note.gnu.property SHT_NOTE sections on AArch64 (a 64-bit target)
should have alignment 8 to more closely match the binutils implementation
where alignment is 4-bytes on 32-bit machines and 8-bytes on 64-bit
machines.

Previously LLD was using 4 for both 32-bit and 64-bit machines.

Differential Revision: https://reviews.llvm.org/D70962
2019-12-05 10:11:31 +00:00
Peter Smith 4d6c4cb426 [LLD][ELF] Add support for PT_GNU_PROPERTY
The PT_GNU_PROPERTY program header describes the location of the
.note.gnu.property SHT_NOTES section. The linux kernel uses this program
header to find the .note.gnu.property section rather than parsing.
Executables that have properties that the kernel needs to act on that don't
have the PT_GNU_PROPERTY program header will not boot.

Differential Revision: https://reviews.llvm.org/D70961
2019-12-05 09:54:58 +00:00
Fangrui Song bf535ac4a2 [ELF][AArch64] Support R_AARCH64_{CALL26,JUMP26} range extension thunks with addends
Fixes AArch64 part of PR40438

The current range extension thunk framework does not handle a relocation
relative to a STT_SECTION symbol with a non-zero addend, which may be
used by jumps/calls to local functions on some RELA targets (AArch64,
powerpc ELFv1, powerpc64 ELFv2, etc).  See PR40438 and the following
code for examples:

  // clang -target $target a.cc
  // .text.cold may be placed in a separate output section.
  // The distance between bar in .text.cold and foo in .text may be larger than 128MiB.
  static void foo() {}
  __attribute__((section(".text.cold"))) static int bar() { foo(); return
  0; }
  __attribute__((used)) static int dummy = bar();

This patch makes such thunks with addends work for AArch64. The target
independent part can be reused by PPC in the future.

On REL targets (ARM, MIPS), jumps/calls are not represented as
STT_SECTION + non-zero addend (see
MCELFObjectTargetWriter::needsRelocateWithSymbol), so they don't need
this feature, but we need to make sure this patch does not affect them.

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D70637
2019-12-02 10:07:24 -08:00
Fangrui Song 3d9b1128d6 [ELF][ARM] Add getPCBias()
ThunkCreator::getThunk and ThunkCreator::normalizeExistingThunk
currently assume that the implicit addends are -8 for ARM and -4 for
Thumb. In D70637, ThunkCreator::getThunk will need to take care of the
relocation addend explicitly.

Add the utility function getPCBias() as a prerequisite so that the getThunk change in D70637
can be more general.

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D70690
2019-11-27 09:09:46 -08:00
Georgii Rymar 3b35603a56 [llvm-readobj] - Always print "Predecessors" for version definition sections.
This is a follow-up discussed in D70495 thread.

The current logic is unusual for llvm-readobj. It doesn't print predecessors
list when it is empty. This is not good for machine parsers.
D70495 had to add this condition during refactoring to reduce amount of changes,
in tests, because the original code also had a similar logic.

Now seems it is time to get rid of it. This patch does it.

Differential revision: https://reviews.llvm.org/D70717
2019-11-27 12:29:55 +03:00
Shoaib Meenai 75fd939bb9 [ELF] Adjust test to work for zlib 1.2.8
The previous data had the same length with compression levels 1 and 6
for zlib 1.2.8. Adjust the test to work for this library version. I've
also tested this with zlib 1.2.7 and zlib 1.2.11.
2019-11-26 17:19:02 -08:00
Fangrui Song 54a366f515 [ELF] Add a corrector for case mismatch problems
Reviewed By: grimar, peter.smith

Differential Revision: https://reviews.llvm.org/D70506
2019-11-26 09:11:56 -08:00
Fangrui Song a2fc964417 [ELF] Replace SymbolTable::forEachSymbol with iterator_range symbols()
D62381 introduced forEachSymbol(). It seems that many call sites cannot
be parallelized because the body shared some states. Replace
forEachSymbol with iterator_range<filter_iterator<...>> symbols() to
simplify code and improve debuggability (std::function calls take some
frames).

It also allows us to use early return to simplify code added in D69650.

Reviewed By: grimar

Differential Revision: https://reviews.llvm.org/D70505
2019-11-26 09:09:32 -08:00
Georgii Rymar 19edd675c6 [LLD][ELF] - Make compression level be dependent on -On.
Currently LLD always use zlib compression level 6.
This patch changes it to use 1 for -O0, -O1 and 6 for -O2.

It fixes https://bugs.llvm.org/show_bug.cgi?id=44089.

There was also a thread in llvm-dev on this topic:
https://lists.llvm.org/pipermail/llvm-dev/2018-August/125020.html

Here is a table with results of building clang mentioned there:

```
Level   Time            Size
0       0m17.128s       2045081496   Z_NO_COMPRESSION
1       0m31.471s       922618584    Z_BEST_SPEED
2       0m32.659s       903642376
3       0m36.749s       890805856
4       0m41.532s       876697184
5       0m48.383s       862778576
6       1m3.176s        855251640    Z_DEFAULT_COMPRESSION
7       1m15.335s       853755920
8       2m0.561s        852497560
9       2m33.972s       852397408    Z_BEST_COMPRESSION
```

It shows that it is probably not reasonable to use values greater than 6.

Differential revision: https://reviews.llvm.org/D70658
2019-11-26 11:50:22 +03:00
Fangrui Song a71c1e2a57 [ELF] Support input section description .rel[a].dyn in /DISCARD/
Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D70695
2019-11-25 21:49:46 -08:00
Fangrui Song f0558f582a [ELF] Delete unused Configuration::zExecstack after D56554 2019-11-25 14:44:09 -08:00
Nemanja Ivanovic 4d5c8caf9b [LLD] Add a default copy constructor to avoid warnings
This should fix the failure on the PPC64LE LLD bot.
2019-11-25 14:09:16 -06:00
Fangrui Song 6b90f2bbec [ELF][test] Clean up some thunk tests
Use llvm-objdump --no-show-raw-insn --print-imm-hex
Prefer generic aarch64 triple to linux/freebsd specific triples.
2019-11-23 12:42:39 -08:00
Fangrui Song 4dc2fb123d [ELF] Error if -Ttext-segment is specified
In GNU ld, -Ttext sets the address of the .text section and -Ttext-segment sets the address of the text segment (RX).

gold only supports the -Ttext-segment semantic and treats -Ttext as an alias for -Ttext-segment.

lld only supports the -Ttext semantic and treats -Ttext-segment as an
alias for -Ttext.  The text segment will be assigned to an address less
than the specified -Ttext-segment value.

This patch drops the -Ttext-segment alias.

The text segment is traditionally the first segment. Users who specify
-Ttext-segment may actually want to specify --image-base, the lld way to
express this. Unfortunately currently this is supported by GNU ld's
COFF port but not by its ELF port. gold does not support this option.
With -z separate-code, the behavior of GNU ld -Ttext-segment is weird (see https://sourceware.org/bugzilla/show_bug.cgi?id=25207)

rL289827 introduced the alias for linking qemu's non-pie user mode
binaries. As explained previously, this actually assigns the text
segment to an address less than 0x60000000. I feel that a better fix is
on the qemu side:
https://lists.nongnu.org/archive/html/qemu-devel/2019-11/msg02480.html

Reviewed By: grimar, ruiu

Differential Revision: https://reviews.llvm.org/D70468
2019-11-21 09:41:55 -08:00
James Y Knight d3fec7fb45 LLD: Don't use the stderrOS stream in link before it's reassigned.
Remove the lld::enableColors function, as it just obscures which
stream it's affecting, and replace with explicit calls to the stream's
enable_colors.

Also, assign the stderrOS and stdoutOS globals first in link function,
just to ensure nothing might use them.

(Either change individually fixes the issue of using the old
stream, but both together seems best.)

Follow-up to b11386f9be.

Differential Revision: https://reviews.llvm.org/D70492
2019-11-21 10:55:03 -05:00
Alex Richardson 5bab291b7b Ignore R_MIPS_JALR relocations against non-function symbols
Summary:
Current versions of clang would erroneously emit this relocation not only
against functions (loaded from the GOT) but also against data symbols
(e.g. a table of function pointers). LLD was then changing this into a
branch-and-link instruction, causing the program to jump to the data
symbol at run time. I discovered this problem when attempting to boot
MIPS64 FreeBSD after updating the to the latest upstream master.

Reviewers: atanasyan, jrtc27, espindola

Reviewed By: atanasyan

Subscribers: emaste, sdardis, krytarowski, MaskRay, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70406
2019-11-20 13:23:26 +00:00
Georgii Rymar 1cc78fdb6f [llvm-readobj/llvm-readelf] - Improve dumping of versioning sections.
Our elf-versioninfo.test is not perfect. It does not properly test how
flags are dumped and also we have a bug: they are dumped as enums in
LLVM style now, i.e not dumped properly.

GNU style uses a `versionFlagToString` method to build a string from flags
which seems is consistent with GNU readelf.

In this patch I fixed the issues mentioned.

Differential revision: https://reviews.llvm.org/D70399
2019-11-20 11:55:55 +03:00
Rui Ueyama 47feae5dd6 Use lld::make<T> to make TpiSource objects
In lld we rarely use std::unique_ptr but instead allocate new instances
using lld::make<T>() so that they are deallocated at the end of linking.
This patch changes existing code so that that follows the convention.

Differential Revision: https://reviews.llvm.org/D70420
2019-11-20 13:14:44 +09:00
Fangrui Song ce5de93e83 [ELF] Disallow out-of-range section group indices after D70146
Exposed by invalid/sht-group-wrong-section.test
http://45.33.8.238/win/2613/step_9.txt
2019-11-19 09:49:45 -08:00
Fangrui Song 6b0eb5a672 [ELF] Improve --gc-sections compatibility with GNU ld regarding section groups
Based on D70020 by serge-sans-paille.

The ELF spec says:

> Furthermore, there may be internal references among these sections that would not make sense if one of the sections were removed or replaced by a duplicate from another object. Therefore, such groups must be included or omitted from the linked object as a unit. A section cannot be a member of more than one group.

GNU ld has 2 behaviors that we don't have:

- Group members (nextInSectionGroup != nullptr) are subject to garbage collection.
  This includes non-SHF_ALLOC SHT_NOTE sections.
  In particular, discarding non-SHF_ALLOC SHT_NOTE sections is an expected behavior by the Annobin
  project. See
  https://developers.redhat.com/blog/2018/02/20/annobin-storing-information-binaries/
  for more information.
- Groups members are retained or discarded as a unit.
  Members may have internal references that are not expressed as
  SHF_LINK_ORDER, relocations, etc. It seems that we should be more conservative here:
  if a section is marked live, mark all the other member within the
  group.

Both behaviors are reasonable. This patch implements them.

A new field InputSectionBase::nextInSectionGroup tracks the next member
within a group. on ELF64, this increases sizeof(InputSectionBase) froms
144 to 152.

InputSectionBase::dependentSections tracks section dependencies, which
is used by both --gc-sections and /DISCARD/. We can't overload it for
the "next member" semantic, because we should allow /DISCARD/ to discard
sections independent of --gc-sections (GNU ld behavior). This behavior
may be reasonably used by `/DISCARD/ : { *(.ARM.exidx*) }` or `/DISCARD/
: { *(.note*) }` (new test `linkerscript/discard-group.s`).

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D70146
2019-11-19 08:54:06 -08:00
Rui Ueyama 45f8ee5f3c Revert "Fix shared lib build."
This reverts commit 17e37ba57a
because it introduced a circular dependency between Core and Common.
Because d0371f4736 fixed a build issue,
we no longer need that dependency.
2019-11-19 12:05:55 +09:00
Rui Ueyama d0371f4736 Fix component build
b11386f9be broke lld build
if `-DBUILD_SHARED_LIBS=ON` is passed to CMake.
2019-11-19 11:20:52 +09:00
Michael Liao 17e37ba57a Fix shared lib build. 2019-11-18 13:08:51 -05:00
Rui Ueyama 909d7bf9a7 Fix Windows buildbots
`stdout` and `stderr` might be defined as macros, so we needed to
avoid using them as variable names.
2019-11-18 16:45:00 +09:00
Rui Ueyama b11386f9be Make it possible to redirect not only errs() but also outs()
This change is for those who use lld as a library. Context:
https://reviews.llvm.org/D70287

This patch adds a new parmeter to lld::*::link() so that we can pass
an raw_ostream object representing stdout. Previously, lld::*::link()
took only an stderr object.

Justification for making stdoutOS and stderrOS mandatory: I wanted to
make link() functions to take stdout and stderr in that order.
However, if we change the function signature from

  bool link(ArrayRef<const char *> args, bool canExitEarly,
            raw_ostream &stderrOS = llvm::errs());

to

  bool link(ArrayRef<const char *> args, bool canExitEarly,
            raw_ostream &stdoutOS = llvm::outs(),
            raw_ostream &stderrOS = llvm::errs());

, then the meaning of existing code that passes stderrOS silently
changes (stderrOS would be interpreted as stdoutOS). So, I chose to
make existing code not to compile, so that developers can fix their
code.

Differential Revision: https://reviews.llvm.org/D70292
2019-11-18 11:18:06 +09:00
Ayke van Laethem 57776f71fa
[ELF] Fix lld build on Windows/MinGW
The patch in https://reviews.llvm.org/D64077 causes a build failure
because both the Defined and SharedSymbol classes are bigger than 80
bytes on MinGW 8.

This patch fixes this build failure by changing the type of the
bitfields. It is a similar change to the bitfield changes in
https://reviews.llvm.org/D64238, but instead of changing to bool I
decided to use uint8_t because one of the bitfields takes up two bits
instead of one.

Note: the patch is slightly different from the one reviewed in
Phabricator, but it is a trivial change to align it with LLVM master
instead of LLVM 9. Also, it passes all lld tests.

Differential Revision: https://reviews.llvm.org/D70266
2019-11-16 13:28:53 +01:00
Reid Kleckner ce0f3ee5e4 [COFF] Don't error if the only inputs are from /wholearchive:
Fixes PR43744

Differential Revision: https://reviews.llvm.org/D69968
2019-11-15 16:09:07 -08:00
Reid Kleckner 4c1a1d3cf9 Add missing includes needed to prune LLVMContext.h include, NFC
These are a pre-requisite to removing #include "llvm/Support/Options.h"
from LLVMContext.h: https://reviews.llvm.org/D70280
2019-11-14 15:23:15 -08:00
Reid Kleckner de3fb1ec05 [COFF] Avoid CodeView include in header
Most LLD/COFF files don't care about CodeView. Avoid using CodeView
types in InputFiles.h.
2019-11-14 14:27:48 -08:00
Reid Kleckner adfad4d7c8 Forward declare the DWARFCache to avoid including LLVM DWARF details
LLD's DWARF.h header leaks a lot of LLVM DWARF includes that LLD doesn't
need. For Chunks.cpp, I see a compile time decrease of 3.1s to 2.7s.
2019-11-14 14:17:49 -08:00
Reid Kleckner f24c3352c9 [COFF] Don't include llvm/LTO/LTO.h in a header
LLVM's LTO header includes all of llvm/IR, which most of the COFF linker
doesn't need.
2019-11-14 13:47:18 -08:00
Rui Ueyama 000ff301e7 Warn on /align if used without /driver
/align is not supposed to be used without /driver, so it makes sense
to warn if only /align is passed. MSVC link.exe warns on this too.

Differential Revision: https://reviews.llvm.org/D70163
2019-11-14 13:13:07 +09:00
Rui Ueyama f95ed69641 Implement /driver, /driver:wdm and /driver:uponly
This patch implements /driver, /driver:wdm and /driver:uponly as
described in
https://docs.microsoft.com/en-us/cpp/build/reference/driver-windows-nt-kernel-mode-driver?view=vs-2019.

Differential Revision: https://reviews.llvm.org/D70162
2019-11-14 13:07:56 +09:00
Martin Storsjö 38bc9559ba [LLD] [COFF] Fix automatically importing data symbols from DLLs with LTO
This broke in 51dcb292cc, "[lld-link] diagnose undefined symbols
before LTO when possible" (very soon after the 9.0 branch, so
luckily the 9.0 release is unaffected).

The code for loading objects we believe might be needed for autoimport
(loadMinGWAutomaticImports()) does run before the new
reportUnresolvable() function, but it had a condition to only operate
on symbols from regular object files. This condition came from
resolveRemainingUndefines(), but as loadMinGWAutomaticImports() now
has to operate before the LTO, it has to operate on undefineds from
LTO objects as well.

Differential Revision: https://reviews.llvm.org/D70166
2019-11-13 22:48:36 +02:00
Fangrui Song 8f089f2099 [MC] Emit unused undefined symbol even if its binding is not set
Recommit r373168, which was reverted by r373242. This actually exposed a
boringssl bug which has been fixed for more than one month.

For the following two cases, we currently suppress the symbols. This
patch emits them (compatible with GNU as).

* `test2_a = undef`: if `undef` is otherwise unused.
* `.hidden hidden`: if `hidden` is unused. This is the main point of the
  patch, because omitting the symbol would cause a linker semantic
  difference.

It causes a behavior change that is not compatible with GNU as:

.weakref foo1, bar1

When neither foo1 nor bar1 is used, we now emit bar1, which is arguably
more consistent.

Another change is that we will emit .TOC. for .TOC.@tocbase .  For this
directive, suppressing .TOC. can be seen as a size optimization, but we
choose to drop it for simplicity and consistency.
2019-11-08 14:47:48 -08:00
Fangrui Song 5b47efa20e [ELF] Fix stack-use-after-scope after D69592 and 69650 2019-11-08 11:21:32 -08:00
Fangrui Song 59d3fbc227 [ELF] Suggest extern "C" when the definition is mangled while an undefined reference is not
The definition may be mangled while an undefined reference is not.
This may come up when (1) the reference is from a C file or (2) the definition
misses an extern "C".

(2) is more common. Suggest an arbitrary mangled name that matches the
undefined reference, if such a definition exists.

  ld.lld: error: undefined symbol: foo
  >>> referenced by a.o:(.text+0x1)
  >>> did you mean to declare foo(int) as extern "C"?
  >>> defined in: a1.o

Reviewed By: dblaikie, ruiu

Differential Revision: https://reviews.llvm.org/D69650
2019-11-08 09:46:45 -08:00
Fangrui Song 70e62a4fa6 [ELF] Suggest extern "C" when an undefined reference is mangled while the definition is not
When missing an extern "C" declaration, an undefined reference may be
mangled while the definition is not. Suggest the missing
extern "C" and the base name.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D69592
2019-11-08 09:42:50 -08:00
Rui Ueyama f95273f75a Keep symbols passed by -init and -fini
Previously, symbols passed by -init and -fini look as if they are
not referenced by anyone, and the LTO might eliminate them.
This patch fixes the issue.

Fixes a bug reported in https://bugs.llvm.org/show_bug.cgi?id=43927

Differential Revision: https://reviews.llvm.org/D69985
2019-11-08 19:08:15 +09:00
Peter Collingbourne 2c6fae179e ELF: Discard .ARM.exidx sections for empty functions instead of misordering them.
The logic added in r372781 caused ARMExidxSyntheticSection::addSection()
to return false for exidx sections without a link order dep that passed
isValidExidxSectionDep(). This included exidx sections for empty functions. As
a result, such exidx sections would end up treated like ordinary sections and
would end up being laid out before the ARMExidxSyntheticSection, most likely in
the wrong order relative to the exidx entries in the ARMExidxSyntheticSection,
breaking the orderedness invariant relied upon by unwinders. Fix this by
simply discarding such sections.

Differential Revision: https://reviews.llvm.org/D69744
2019-11-04 09:11:14 -08:00
Reid Kleckner deaf121b65 Warn when an output section name is longer than 8 characters
Recent versions of Microsoft's dumpbin tool cannot handle such PE files.
LLVM tools and GNU tools can, and use this to encode long section names
like ".debug_info", which is commonly used for DWARF. Don't do this in
mingw mode or when -debug:dwarf is passed, since the user probably wants
long section names for DWARF sections.

PR43754

Reviewers: ruiu, mstorsjo

Differential Revision: https://reviews.llvm.org/D69594
2019-11-01 12:59:13 -07:00
Nico Weber 07255f81fa comment typo fix to cycle bots 2019-10-31 07:54:16 -04:00
Nico Weber 4138fc9567 comment typo fix to cycle bots 2019-10-30 22:17:52 -04:00
Fangrui Song db8dad20b3 [ELF][test] Change references of %T to %t.dir
Test files in the same directory share the same %T.  %T is easy to
misuse and cause race conditions (when running concurrently) so it has
been deprecated since D48842 (see docs/CommandGuide/lit.rst).

While here, add `rm -rf %t.dir` so that tests cannot depend on old files lying around.

Reviewed By: jhenderson, ruiu

Differential Revision: https://reviews.llvm.org/D69572
2019-10-30 09:22:48 -07:00
Georgii Rymar d213da49e1 [LLD] - Fix a test after obj2yaml change.
I am not sure why obj2yaml is used to check the linkers output,
but anyways, the format was changed in https://reviews.llvm.org/rG6e779e953e9d.
2019-10-30 18:28:52 +03:00
Sam Clegg baff8ec2e1 [WebAssembly][lld] Fix for static linking of PIC code
When statically linking PIC code we create an internalized __memory_base
so that memory-base-relative relocation work correctly.  The value of
this global should be zero, and not the globalBase since the globalBase
offset is already taken into account by getVirtualAddress.

Fixes: https://github.com/emscripten-core/emscripten/issues/9013

Differential Revision: https://reviews.llvm.org/D69600
2019-10-29 18:58:56 -07:00
Nick Terrell 6814232429 [LLD][ELF] Support --[no-]mmap-output-file with F_no_mmap
Summary:
Add a flag `F_no_mmap` to `FileOutputBuffer` to support
`--[no-]mmap-output-file` in ELF LLD. LLD currently explicitly ignores
this flag for compatibility with GNU ld and gold.

We need this flag to speed up link time for large binaries in certain
scenarios. When we link some of our larger binaries we find that LLD
takes 50+ GB of memory, which causes memory pressure. The memory
pressure causes the VM to flush dirty pages of the output file to disk.
This is normally okay, since we should be flushing cold pages. However,
when using BtrFS with compression we need to write 128KB at a time when
we flush a page. If any page in that 128KB block is written again, then
it must be flushed a second time, and so on. Since LLD doesn't write
sequentially this causes write amplification. The same 128KB block will
end up being flushed multiple times, causing the linker to many times
more IO than necessary. We've observed 3-5x faster builds with
-no-mmap-output-file when we hit this scenario.

The bad scenario only applies to compressed filesystems, which group
together multiple pages into a single compressed block. I've tested
BtrFS, but the problem will be present for any compressed filesystem
on Linux, since it is caused by the VM.

Silently ignoring --no-mmap-output-file caused a silent regression when
we switched from gold to lld. We pass --no-mmap-output-file to fix this
edge case, but since lld silently ignored the flag we didn't realize it
wasn't being respected.

Benchmark building a 9 GB binary that exposes this edge case. I linked 3
times with --mmap-output-file and 3 times with --no-mmap-output-file and
took the average. The machine has 24 cores @ 2.4 GHz, 112 GB of RAM,
BtrFS mounted with -compress-force=zstd, and an 80% full disk.

| Mode    | Time  |
|---------|-------|
| mmap    | 894 s |
| no mmap | 126 s |

When compression is disabled, BtrFS performs just as well with and
without mmap on this benchmark.

I was unable to reproduce the regression with any binaries in
lld-speed-test.

Reviewed By: ruiu, MaskRay

Differential Revision: https://reviews.llvm.org/D69294
2019-10-29 15:49:08 -07:00
Fangrui Song 94bfa6deb0 [ELF] Delete redundant comment after D56554. NFC 2019-10-29 10:00:48 -07:00
Michał Górny 2a0fcae3d4 [lld] [ELF] Add '-z nognustack' opt to suppress emitting PT_GNU_STACK
Add a new '-z nognustack' option that suppresses emitting PT_GNU_STACK
segment.  This segment is not supported at all on NetBSD (stack is
always non-executable), and the option is meant to be used to disable
emitting it.

Differential Revision: https://reviews.llvm.org/D56554
2019-10-29 17:54:23 +01:00
Nico Weber 5976a3f5aa Fix a few typos in lld/ELF to cycle bots 2019-10-28 21:41:47 -04:00
Nico Weber b911d2db5d lld/COFF: Simplify getOutputPath() using sys::path functions.
Also mention "basename" and "dirname" in Path.h since I tried
to find these functions by looking for these strings. It might
help others find them faster if the comments contain these strings.

No behavior change.

Differential Revision: https://reviews.llvm.org/D69458
2019-10-28 10:38:32 -04:00
Sterling Augustine 118ceea5c3 Crt files are special cased by name when dealing with ctor and dtor
sections, but the current code misses certain variants. In particular, those
named when clang takes the code path in
clang/lib/Driver/ToolChain.cpp:416, where crtfiles are named:

clang_rt.<component>-<arch>-<env>.<suffix>

Previously, the code only handled:
clang_rt.<component>.<suffix>
<component>.<suffix>

This revision fixes that.
2019-10-25 11:04:56 -07:00
georgerim e3105e71f3 [LLD][ELF] - Update test case after yaml2obj change.
SHT_NOTE needs at least an empty "Content" in the YAML description.
Should fix http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-ubuntu-fast
2019-10-25 13:40:44 +03:00
Fangrui Song 56d81104f1 [ELF] -r: fix crash when processing a SHT_REL[A] that relocates a SHF_MERGE after D67504/r372734
Fix PR43767

In -r mode, when processing a SHT_REL[A] that relocates a SHF_MERGE, sec->getRelocatedSection() is a
MergeInputSection and its parent is an OutputSection but is asserted to
be a SyntheticSection (MergeSyntheticSection) in LinkerScript.cpp:addInputSec().
 ##
The code path is not exercised in non -r mode because the relocated
section changed from MergeInputSection to InputSection.

Reorder the code to make the non -r logic apply to -r as well, thus fix
the crash.

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D69364
2019-10-24 11:35:29 -07:00
LLVM GN Syncbot f86dc64bad typo fix test commit 2019-10-22 21:32:11 +00:00
Nico Weber e0e7d06df3 fix a few typos to test git committing 2019-10-22 16:34:00 -04:00
Martin Storsjo 150a9ad3ff [LLD] [COFF] Fix use of uninitialized memory since SVN r375390
llvm-svn: 375400
2019-10-21 09:35:34 +00:00
Martin Storsjo 65b1c497d2 [LLD] [COFF] Use the local dwarf code instead of Symbolizer for resolving code locations. NFC.
As we now have code that parses the dwarf info for variable locations,
we can use that instead of relying on the higher level Symbolizer library,
reducing the previous two different dwarf codepaths into one.

Differential Revision: https://reviews.llvm.org/D69198

llvm-svn: 375391
2019-10-21 08:01:59 +00:00
Martin Storsjo 908b780952 [LLD] Move duplicated dwarf parsing code to the Common library. NFC.
Differential Revision: https://reviews.llvm.org/D69197

llvm-svn: 375390
2019-10-21 08:01:52 +00:00
George Rimar c4107383e5 [LLD][ELF] - Update tests after yaml2obj tool update.
yaml2obj doesn't create .symtab by default anymore.

llvm-svn: 375360
2019-10-20 14:47:09 +00:00
Reid Kleckner 90c64a3456 Move endian constant from Host.h to SwapByteOrder.h, prune include
Works on this dependency chain:
  ArrayRef.h ->
  Hashing.h -> --CUT--
  Host.h ->
  StringMap.h / StringRef.h

ArrayRef is very popular, but Host.h is rarely needed. Move the
IsBigEndianHost constant to SwapByteOrder.h. Clients of that header are
more likely to need it.

llvm-svn: 375316
2019-10-19 00:48:11 +00:00
Thomas Lively 393d0f799f [WebAssembly] Allow multivalue signatures in object files
Summary:
Also changes the wasm YAML format to reflect the possibility of having
multiple return types and to put the returns after the params for
consistency with the binary encoding.

Reviewers: aheejin, sbc100

Subscribers: dschuff, jgravelle-google, hiraditya, sunfish, arphaman, rupprecht, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D69156

llvm-svn: 375283
2019-10-18 20:27:30 +00:00
Michael Liao 92fea8bb8d [lld][coff] Add missing dependency to fix build.
llvm-svn: 375238
2019-10-18 14:31:58 +00:00
Martin Storsjo b38f577c01 [LLD] [COFF] Try to report source locations for duplicate symbols
This fixes the second part of PR42407.

For files with dwarf debug info, it manually loads and iterates
.debug_info to find the declared location of variables, to allow
reporting them. (This matches the corresponding code in the ELF
linker.)

For functions, it uses the existing getFileLineDwarf which uses
LLVMSymbolizer for translating addresses to file lines.

In object files with codeview debug info, only the source location
of duplicate functions is printed. (And even there, only for the
first input file. The getFileLineCodeView function requires the
object file to be fully loaded and initialized to properly resolve
source locations, but duplicate symbols are reported at a stage when
the second object file isn't fully loaded yet.)

Differential Revision: https://reviews.llvm.org/D68975

llvm-svn: 375218
2019-10-18 10:43:15 +00:00
Rui Ueyama 9a5ad9bd5a Update release notes
llvm-svn: 375206
2019-10-18 06:11:16 +00:00
Jordan Rupprecht ce88cdf096 [lld][test] Speculative fix for lld+windows failures
This updates some more places using `%T` to use `%/T` for path normalization.

If this does not work, this and r375126 should be reverted together.

llvm-svn: 375131
2019-10-17 16:29:03 +00:00
Jordan Rupprecht 1b6c3ca126 [lld][test] Fix use of escape character in an lld test on Windows
Summary:
Glob support was improved to accept `\` as an escape character in r375051, but reverted as r375052 due to a failure in this test on Windows.

The reason this failure seems Windows specific is because the path separator `\` is currently being relied on to be interpreted literally instead of as an escape character. Per documentation on linker input section wildcard patterns, this seems to be a bug in lld accepting `\` as a literal instead of an escape character.

For example:
```
SECTIONS{ .foo :{ /path/to/foo.o(.foo) }} # OK: standard UNIX path
SECTIONS{ .foo :{ C:/path/to/foo.o(.foo) }} # OK: windows accepts slashes in either direction
SECTIONS{ .foo :{ C:\\path\\to\\foo.o(.foo) }} # OK: escape character used to match a literal \
SECTIONS{ .foo :{ C:\path\to\foo.o(.foo) }} # BAD: this actually matches the path C:pathtofoo.o(.foo)
```

This avoids the problem in the test by using `%/T` in place of `%T` to normalize the path separator to `/`, which windows should also accept.

This patch just fixes the test, and glob support will be be relanded separately.

For a sample buildbot error, see: http://lab.llvm.org:8011/builders/clang-x64-windows-msvc/builds/11578/steps/stage%201%20check/logs/stdio

Reviewers: evgeny777, ruiu, MaskRay, espindola

Reviewed By: ruiu, MaskRay

Subscribers: emaste, arichardson, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D69074

llvm-svn: 375126
2019-10-17 15:35:28 +00:00
George Rimar 938db706fe [LLD][ELF] - Update test cases after llvm-readobj output format change.
The change was:

SHT_GNU_verdef { -> VersionDefinitions [
SHT_GNU_verneed { -> VersionRequirements [
Version symbols [ -> VersionSymbols [
EH_FRAME Header [ -> EHFrameHeader {

llvm-svn: 375096
2019-10-17 10:23:59 +00:00
Sam Clegg 67b055841f [lld][WebAssebmly] Preserve custom import attributes with LTO
Undefined symbols in WebAssembly can come with custom `import-module`
and `import-field` attributes.  However when reading symbols from
bitcode object files during LTO those curtom attributes are not
available.

Once we compile the LTO object and read in the symbol table from the
object file we have access to these custom attributes.  In this case,
when undefined symbols are added and a symbol already exists in the
SymbolTable we can't simple return it, we may need to update the
symbol's attributes.

Fixes: PR43211

Differential Revision: https://reviews.llvm.org/D68959

llvm-svn: 375081
2019-10-17 05:16:54 +00:00
Sam Clegg 6c393e9d74 [lld][WebAssembly] Fix for weak references to data symbols in archives
Fix a bug where were not handling relocations against weakly undefined
data symbol.  Add a test for this case.  Also ensure that the weak
references to data symbols are not pulled in from archive files by
default (but are if `-u <name>` is added to the command line).

Fixes: PR43696

Differential Revision: https://reviews.llvm.org/D69073

llvm-svn: 375077
2019-10-17 03:21:02 +00:00
Thomas Lively 190dacc3cc [WebAssembly] Elide data segments for .bss sections
Summary:
WebAssembly memories are zero-initialized, so when module does not
import its memory initializing .bss sections is guaranteed to be a
no-op. To reduce binary size and initialization time, .bss sections
are simply not emitted into the final binary unless the memory is
imported.

Reviewers: sbc100

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68965

llvm-svn: 374940
2019-10-15 19:05:11 +00:00
James Clarke 1ab27c74d4 [lld][WebAssembly] Fix static linking of -fPIC code with external undefined data
Reviewers: ruiu, sbc100

Reviewed By: sbc100

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68991

llvm-svn: 374913
2019-10-15 17:05:42 +00:00
Sid Manning ab50256544 [lld] Check for branch range overflows.
Differential Revision: https://reviews.llvm.org/D68875

llvm-svn: 374891
2019-10-15 14:12:54 +00:00
Martin Storsjo e0916f4fbe [LLD] [COFF] Update a leftover comment after SVN r374869. NFC.
llvm-svn: 374874
2019-10-15 09:46:33 +00:00
Martin Storsjo cd8759c3c2 [LLD] [COFF] Fix -Wmissing-field-initializers warnings. NFC.
llvm-svn: 374873
2019-10-15 09:33:14 +00:00
Martin Storsjo 9318c94ebb [LLD] [COFF] Wrap file location pair<StringRef,int> in Optional<>. NFC.
This makes use of it slightly clearer, and makes it match the
same construct in the lld ELF linker.

Differential Revision: https://reviews.llvm.org/D68935

llvm-svn: 374869
2019-10-15 09:18:18 +00:00
Jordan Rupprecht c526ff8a62 [llvm-objdump] Adjust spacing and field width for --section-headers
Summary:
- Expand the "Name" column past 13 characters when any of the section names are longer. Current behavior is a staggard output instead of a nice table if a single name is longer.
- Only print the required number of hex chars for addresses (i.e. 8 characters for 32-bit, 16 characters for 64-bit)
- Fix trailing spaces

Reviewers: grimar, jhenderson, espindola

Reviewed By: grimar

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68730

llvm-svn: 374795
2019-10-14 17:47:17 +00:00
George Rimar a8346cee8a [LLD][ELF] - Update test cases after llvm-readobj change.
https://reviews.llvm.org/D68704 changed the output format.

llvm-svn: 374542
2019-10-11 12:27:20 +00:00