This avoids a spurious and confusing log message in cases where
both e.g. "alias" and "__imp_alias" exist.
Differential Revision: https://reviews.llvm.org/D65598
llvm-svn: 367673
1. raw_ostream supports ANSI colors so that you can write messages to
the termina with colors. Previously, in order to change and reset
color, you had to call `changeColor` and `resetColor` functions,
respectively.
So, if you print out "error: " in red, for example, you had to do
something like this:
OS.changeColor(raw_ostream::RED);
OS << "error: ";
OS.resetColor();
With this patch, you can write the same code as follows:
OS << raw_ostream::RED << "error: " << raw_ostream::RESET;
2. Add a boolean flag to raw_ostream so that you can disable colored
output. If you disable colors, changeColor, operator<<(Color),
resetColor and other color-related functions have no effect.
Most LLVM tools automatically prints out messages using colors, and
you can disable it by passing a flag such as `--disable-colors`.
This new flag makes it easy to write code that works that way.
Differential Revision: https://reviews.llvm.org/D65564
llvm-svn: 367649
The Archive object created when loading an archive specified with
wholearchive got cleaned up immediately, when the owning std::unique_ptr
went out of scope, even if persisted StringRefs pointed to memory that
belonged to the archive, which no longer was mapped in memory.
This hasn't been an issue with regular (as opposed to thin) archives,
as references to the member objects has kept the mapping for the whole
archive file alive - but with thin archives, all such references point
to other files.
Add the std::unique_ptr to the arena allocator, to retain it as long
as necessary.
This fixes (the last issue raised in) PR42388.
Differential Revision: https://reviews.llvm.org/D65565
llvm-svn: 367599
This patch
1) adds -z separate-code and -z noseparate-code (default).
2) changes the condition that the last page of last PF_X PT_LOAD is
padded with trap instructions.
Current condition (after D33630): if there is no `SECTIONS` commands.
After this change: if -z separate-code is specified.
-z separate-code was introduced to ld.bfd in 2018, to place the text
segment in its own pages. There is no overlap in pages between an
executable segment and a non-executable segment:
1) RX cannot load initial contents from R or RW(or non-SHF_ALLOC).
2) R and RW(or non-SHF_ALLOC) cannot load initial contents from RX.
lld's current status:
- Between R and RX: in `Writer<ELFT>::fixSectionAlignments()`, the start of a
segment is always aligned to maxPageSize, so the initial contents loaded by R
and RX do not overlap. I plan to allow overlaps in D64906 if -z noseparate-code
is in effect.
- Between RX and RW(or non-SHF_ALLOC if RW doesn't exist):
we currently unconditionally pad the last page to commonPageSize
(defaults to 4096 on all targets we support).
This patch will make it effective only if -z separate-code is specified.
-z separate-code is a dubious feature that intends to reduce the number
of ROP gadgets (which is actually ineffective because attackers can find
plenty of gadgets in the text segment, no need to find gadgets in
non-code regions).
With the overlapping PT_LOAD technique D64906, -z noseparate-code
removes two more alignments at segment boundaries than -z separate-code.
This saves at most defaultCommonPageSize*2 bytes, which are significant
on targets with large defaultCommonPageSize (AArch64/MIPS/PPC: 65536).
Issues/feedback on alignment at segment boundaries to help understand
the implication:
* binutils PR24490 (the situation on ld.bfd is worse because they have
two R-- on both sides of R-E so more alignments.)
* In binutils, the 2018-02-27 commit "ld: Add --enable-separate-code" made -z separate-code the default on Linux.
d969dea983
In musl-cross-make, binutils is configured with --disable-separate-code
to address size regressions caused by -z separate-code. (lld actually has the same
issue, which I plan to fix in a future patch. The ld.bfd x86 status is
worse because they default to max-page-size=0x200000).
* https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=237676 people want
smaller code size. This patch will remove one alignment boundary.
* Stef O'Rear: I'm opposed to any kind of page alignment at the
text/rodata line (having a partial page of text aliased as rodata and
vice versa has no demonstrable harm, and I actually care about small
systems).
So, make -z noseparate-code the default.
Reviewed By: ruiu
Differential Revision: https://reviews.llvm.org/D64903
llvm-svn: 367537
We extract and print the source location in the message header so that
Visual Studio is able to parse it and jump there. As duplicate symbols
are defined in several locations, it is more convenient to have separate
error messages, which allows a user to easily access all the locations.
Differential Revision: https://reviews.llvm.org/D65213
llvm-svn: 367536
* Add --no-show-raw-insn to llvm-objdump -d tests
* When linking an executable with %t.so, the path %t.so will be recorded
in the DT_NEEDED entry if %t.so doesn't have DT_SONAME. .dynstr will
have varying lengths on different systems. Add -soname so that the
string in .dynstr is of fixed length to make tests more robust.
* Rename i386-tls-initial-exec-local.s to i386-tls-ie-local.s
* Refactor tls-initial-exec-local.s to x86-64-tls-ie-local.s
llvm-svn: 367533
Previously, when `--vs-diagnostics` was used, the linker printed
something like
hidden(undef.s): error: undefined hidden symbol: foo
>>> referenced by undef.s:15
Differential Revision: https://reviews.llvm.org/D65499
llvm-svn: 367515
Summary:
This allows reporting undefined symbols before LTO codegen is
run. Since LTO codegen can take a long time, this improves user
experience by avoiding that time spend if the link is going to
fail with undefined symbols anyway.
Fixes PR32400.
Reviewers: ruiu
Reviewed By: ruiu
Subscribers: mehdi_amini, steven_wu, dexonsmith, mstorsjo, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62434
llvm-svn: 367136
* Add --no-show-raw-insn to llvm-objdump -d tests
* When linking an executable with %t.so, the path %t.so will be recorded
in the DT_NEEDED entry if %t.so doesn't have DT_SONAME. .dynstr will
have varying lengths on different systems. Add -soname to make tests
more robust.
llvm-svn: 366988
Summary:
We want the tool conventions to state that `__tls_align` will be a power of 2.
It makes sense to not have an exception for when there is no TLS.
Reviewers: tlively, sunfish
Reviewed By: tlively
Subscribers: dschuff, sbc100, jgravelle-google, aheejin, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65177
llvm-svn: 366948
Summary:
This could previously happen if errors that are emitted after reaching the
error limit. In that case, the flag inside the newline() function will be
set to true which causes the next call to print a newline even though the
actual message will be discarded.
Reviewers: ruiu, grimar, MaskRay, espindola
Reviewed By: ruiu
Subscribers: emaste, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65198
llvm-svn: 366944
This ports r366573 from COFF to ELF.
There are now to toString(Archive::Symbol), one doing MSVC demangling
in COFF and one doing Itanium demangling in ELF, so rename these two
to toCOFFString() and to toELFString() to not get a duplicate symbol.
Nothing ever passes a raw Archive::Symbol to CHECK(), so these not
being part of the normal toString() machinery seems ok.
There are two code paths in the ELF linker that emits this type of
diagnostic:
1. The "normal" one in InputFiles.cpp. This is covered by the tweaked test.
2. An additional one that's only used for libcalls if there's at least
one bitcode in the link, and if the libcall symbol is lazy, and
lazily loaded from an archive (i.e. not from a lazy .o file).
(This code path was added in r339301.) Since all libcall names so far
are C symbols and never mangled, the change there is not observable
and hence not covered by tests.
Differential Revision: https://reviews.llvm.org/D65095
llvm-svn: 366836
Code built for mingw with -fdata-sections will store each TLS variable
in a comdat section, named .tls$$<varname>. Normal TLS variables are
stored in sections named .tls$ with a trailing dollar, which are
sorted after a starter marker (in a later linked object file) in a
section named ".tls" (with no dollar suffix), before an ending marker
in a section named ".tls$ZZZ".
The mingw comdat section suffix stripping introduced in SVN r363457
broke sorting of such tls sections, ending up sorting the stripped
.tls$$<varname> sections (stripped to ".tls") before the start marker
in the section named ".tls".
We could add exceptions to the section name suffix stripping for
.tls (and .CRT, where suffixes always should be honored), but the
more conservative option is probably the reverse; to only apply the
stripping for the normal sections where sorting shouldn't have any
effect.
Differential Revision: https://reviews.llvm.org/D65018
llvm-svn: 366780
lld currently selects the relocation model automatically depending on
the link flags specified, but in some cases it'd be useful to allow
explicitly overriding the relocation model using a flag.
llvm-svn: 366644
Summary:
Add immutable WASM global `__tls_align` which stores the alignment
requirements of the TLS segment.
Add `__builtin_wasm_tls_align()` intrinsic to get this alignment in Clang.
The expected usage has now changed to:
__wasm_init_tls(memalign(__builtin_wasm_tls_align(),
__builtin_wasm_tls_size()));
Reviewers: tlively, aheejin, sbc100, sunfish, alexcrichton
Reviewed By: tlively
Subscribers: dschuff, jgravelle-google, hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D65028
llvm-svn: 366624
Also add test coverage for thin archives (which are the only way I could
come up with to test at least some of the diagnostic changes).
Differential Revision: https://reviews.llvm.org/D64927
llvm-svn: 366573
* Delete aarch64-tls-static.s: it is covered by aarch64-tlsdesc.c
* Add --no-show-raw-insn to llvm-objdump -d tests
* When linking an executable with %t.so, the path %t.so will be recorded in the DT_NEEDED entry if %t.so doesn't have DT_SONAME. The DT_NEEDED has varying lengths on different systems.
Add -soname to make tests more robust. This issue will become outstanding if we allow overlapping PT_LOAD (D64930).
llvm-svn: 366532
Summary:
This change makes it so that passing --shared-memory is all a user
needs to do to get proper multithreaded code. This default can still
be explicitly overridden for any reason using --passive-segments and
--active-segments.
Reviewers: sbc100, quantum
Subscribers: dschuff, jgravelle-google, aheejin, sunfish, jfb, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64950
llvm-svn: 366504
Avoid splitting the test into multiple files and use zero for the value of
the symbol with addends at relocations so that it's clear what value is
being used at relocations.
Differential Revision: https://reviews.llvm.org/D64684
llvm-svn: 366463
It's possible to create IR that uses !associated to refer to a global that
appears later in the module, which can result in these types of forward
references being generated. Unfortunately our assembler does not currently
accept the resulting .s so I needed to use yaml2obj to test this.
Differential Revision: https://reviews.llvm.org/D64880
llvm-svn: 366460
basic64be.s is a big-endian powerpc64 test that just duplicates what
basic-ppc64.s does. Extend basic-ppc64.s to add big-endian tests.
Delete basic64be.s
Rename basic32.s to basic-i386.s
llvm-svn: 366401
When hidden symbols are discarded by comdat rules we still want to
create a local defined symbol, otherwise `Symbol::isDiscarded()` relies
on begin able to check `getChunk->discarded`.
This is a followup on rL362769. The comdat.ll test was previously GC'ing
the `__wasm_call_ctors` functions so `do_init` was not actually being
included in the link. Once that function was included in triggered the
crash bug that this change addresses.
Fixes: https://github.com/emscripten-core/emscripten/issues/8981
Differential Revision: https://reviews.llvm.org/D64872
llvm-svn: 366358
Summary:
Add a --vs-diagnostics flag that alters the format of diagnostic output
to enable source hyperlinks in Visual Studio.
Differential Revision: https://reviews.llvm.org/D58484
Reviewed by: ruiu
llvm-svn: 366333
Summary:
Thread local variables are placed inside a `.tdata` segment. Their symbols are
offsets from the start of the segment. The address of a thread local variable
is computed as `__tls_base` + the offset from the start of the segment.
`.tdata` segment is a passive segment and `memory.init` is used once per thread
to initialize the thread local storage.
`__tls_base` is a wasm global. Since each thread has its own wasm instance,
it is effectively thread local. Currently, `__tls_base` must be initialized
at thread startup, and so cannot be used with dynamic libraries.
`__tls_base` is to be initialized with a new linker-synthesized function,
`__wasm_init_tls`, which takes as an argument a block of memory to use as the
storage for thread locals. It then initializes the block of memory and sets
`__tls_base`. As `__wasm_init_tls` will handle the memory initialization,
the memory does not have to be zeroed.
To help allocating memory for thread-local storage, a new compiler intrinsic
is introduced: `__builtin_wasm_tls_size()`. This instrinsic function returns
the size of the thread-local storage for the current function.
The expected usage is to run something like the following upon thread startup:
__wasm_init_tls(malloc(__builtin_wasm_tls_size()));
Reviewers: tlively, aheejin, kripken, sbc100
Subscribers: dschuff, jgravelle-google, hiraditya, sunfish, jfb, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D64537
llvm-svn: 366272
Summary:
Fixes PR41828. Before this, LLD always emitted SafeSEH chunks and
defined __safe_se_handler_table & size. Now, /safeseh:no leaves those
undefined.
Additionally, we were checking for the safeseh @feat.00 flag in two
places: once to emit errors, and once during safeseh table construction.
The error was set up to be off by default, but safeseh is supposed to be
on by default. I combined the two checks, so now LLD emits an error if
an input object lacks @feat.00 and safeseh is enabled. This caused the
majority of 32-bit LLD tests to fail, since many test input object files
lack @feat.00 symbols. I explicitly added -safeseh:no to those tests to
preserve behavior.
Finally, LLD no longer sets IMAGE_DLL_CHARACTERISTICS_NO_SEH if any
input file wasn't compiled for safeseh.
Reviewers: mstorsjo, ruiu, thakis
Reviewed By: ruiu, thakis
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63570
llvm-svn: 366238
This reverts r365990 (git commit 1a6053ebc6)
The test no longer depends on the Visual C++ libraries. I confirmed that
the crash still reproduces with the new test case if I remove the null
check.
llvm-svn: 366095
Summary:
This was causing large addresses to be emitted as negative numbers,
which rightfully caused crashes in binaryen.
Reviewers: aheejin, dschuff
Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64612
llvm-svn: 365930
Before rL295040 the linker just crashed when a GOT relocation (R_MIPS_GOT16)
comes from a merge section. To ensure that this bug still fixed it's enough
to check that the linker does not crash and create GOT entries.
llvm-svn: 365834
E.g. for x86_64, previously each symbol's thunk was 87 bytes. Now
there's a 12 byte thunk per symbol, plus a shared 83 byte tail
function.
This is similar to what both MS link.exe and GNU tools do for
delay imports.
Differential Revision: https://reviews.llvm.org/D64288
llvm-svn: 365823
Summary:
Adds the following two options to lld-link:
-thinlto-prefix-replace: allows replacing a prefix in paths generated
for ThinLTO. This can be used to ensure index files and native object
files are stored in unique directories, allowing multiple distributed
ThinLTO links to proceed concurrently.
-thinlto-object-suffix-replace: allows replacing a suffix in object
file paths involved in ThinLTO. This allows minimized index files to
be used for the thin link while storing the paths to the full bitcode
files for subsequent steps (code generation and final linking).
Reviewers: ruiu, tejohnson, pcc, rnk
Subscribers: mehdi_amini, steven_wu, dexonsmith, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64542
llvm-svn: 365807
Summary:
This implements -thinlto-index-only, -thinlto-index-only:,
and -thinlto-emit-imports-files options in lld-link. They are
analogous to their counterparts in ld.lld: -thinlto-index-only
causes us to perform ThinLTO's thin link and write index files,
but not perform code generation. -thinlto-index-only: does the
same, but also writes a text file listing the native object
files expected to be generated. -thinlto-emit-imports-files
creates a text file next to each index file, listing the files
to import from.
Reviewers: ruiu, tejohnson, pcc, rnk
Subscribers: mehdi_amini, steven_wu, dexonsmith, arphaman, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64461
llvm-svn: 365800
This fixes PR38549, which is silently accepted by ld.bfd.
This seems correct because it makes sense to let non-glob patterns take
precedence over glob patterns.
lld issues an error because
`assignWildcardVersion(ver, VER_NDX_LOCAL);` is processed before `assignExactVersion(ver, v.id, v.name);`.
Move all assignWildcardVersion() calls after assignExactVersion() calls
to fix this.
Also, move handleDynamicList() to the bottom. computeBinding() called by
includeInDynsym() has this cryptic rule:
if (versionId == VER_NDX_LOCAL && isDefined() && !isPreemptible)
return STB_LOCAL;
Before the change:
* foo's version is set to VER_NDX_LOCAL due to `local: *`
* handleDynamicList() is called
- foo.computeBinding() is STB_LOCAL
- foo.includeInDynsym() is false
- foo.isPreemptible is not set (wrong)
* foo's version is set to V1
After the change:
* foo's version is set to VER_NDX_LOCAL due to `local: *`
* foo's version is set to V1
* handleDynamicList() is called
- foo.computeBinding() is STB_GLOBAL
- foo.includeInDynsym() is true
- foo.isPreemptible is set (correct)
Reviewed By: ruiu
Differential Revision: https://reviews.llvm.org/D64550
llvm-svn: 365760
In lvm2, libdevmapper.so is linked with a version script with duplicate
version assignments:
DM_1_02_138 { global: ... dm_bitset_parse_list; ... };
DM_1_02_129 { global: ... dm_bitset_parse_list; ... };
ld.bfd silently accepts this while gold issues a warning. We currently
error, thus inhibit producing the executable. Change the error to
warning to allow this case, and improve the message.
There are some cases where ld.bfd error
`anonymous version tag cannot be combined with other version tags`
but we just warn. It is probably OK for now.
Reviewed By: grimar, ruiu
Differential Revision: https://reviews.llvm.org/D64549
llvm-svn: 365759
D64130 introduced a bug described in the following message:
https://reviews.llvm.org/D64130#1571560
The problem can happen with the following script:
SECTIONS {
.out : {
...
FILL(0x10101010)
*(.aaa)
...
}
The current code tries to read (0x10101010) as an expression and
does not break when meets *, what results in a script parsing error.
In this patch, I verify that FILL command's expression always wrapped in ().
And at the same time =<fillexp> expression can be both wrapped or unwrapped.
I checked it matches to bfd/gold.
Differential revision: https://reviews.llvm.org/D64476
llvm-svn: 365635
This puts handling of undefined symbols in a single location. Its
also more in line with the ELF backend which only reports undefined
symbols based on relocations.
One side effect is that we no longer report undefined symbols that are
only referenced in GC'd sections.
This also fixes a crash reported in the emscripten toolchain:
https://github.com/emscripten-core/emscripten/issues/8930.
Differential Revision: https://reviews.llvm.org/D64280
llvm-svn: 365553
This test was added by D64200/r365139 to check we don't merge
SHF_MERGE|SHF_STRINGS sections with different alignments (that wastes
space and can make MergeTailAlignment::Builder out of sync).
It has nothing to do with tail merge (-O2), so rename it.
llvm-svn: 365442
With this, `clang-cl /source-charset:utf-16 test.cc` now prints `invalid
value 'utf-16' in '/source-charset:utf-16'` instead of `invalid value
'utf-16' in '-finput-charset=utf-16'` before, and several other clang-cl
flags produce much less confusing output as well.
Fixes PR29106.
Since an arg and its alias can have different arg types (joined vs not)
and different values (because of AliasArgs<>), I chose to give the Alias
its own Arg object. For convenience, I just store the alias directly in
the unaliased arg – there aren't many arg objects at runtime, so that
seems ok.
Finally, I changed Arg::getAsString() to use the alias's representation
if it's present – that function was already documented as being the
suitable function for diagnostics, and most callers already used it for
diagnostics.
Implementation-wise, Arg::accept() previously used to parse things as
the unaliased option. The core of that switch is now extracted into a
new function acceptInternal() which parses as the _aliased_ option, and
the previously-intermingled unaliasing is now done as an explicit step
afterwards.
(This also changes one place in lld that didn't use getAsString() for
diagnostics, so that that one place now also prints the flag as the user
wrote it, not as it looks after it went through unaliasing.)
Differential Revision: https://reviews.llvm.org/D64253
llvm-svn: 365413
We should be generating one __start/__stop pair per output segment
not per input segment. The test wasn't catching this because it was
only linking a single object file.
Fixes PR41565
Differential Revision: https://reviews.llvm.org/D64148
llvm-svn: 365308
Since OPT_UNKNOWN args never have any values and consist only of
spelling (and are never aliased), this doesn't make any difference in
practice, but it's more consistent with Arg's guidance to use
getAsString() for diagnostics, and it matches what clang does.
Also tweak two tests to use an unknown option that contains '=' for
additional coverage while here. (The new tests pass fine with the old
code too though.)
llvm-svn: 365200
- The code tried to pass false to split()'s KeepEmpty parameter, but
instead passed it to MaxSplit. As a result, it would never split on
commas. This has been broken since the flag was added in r278056.
- The code used getSpelling() for getting the argument's values, but
getSpelling() always returns the `/debugtype:` prefix without any
values. So if any /debugtype: flag was passed, it always resulted in
an "unknown option:" warning. (The warning code then used the correct
getValue() for printing the invalid option, so the warning looked
kind of like it made sense.) This regressed in r342894.
Slightly improve the test coverage of this feature (but since I don't
know what this flag actually does, there's still no test for the correct
semantics), and add a comment to getSpelling() explaining what it does.
llvm-svn: 365182
The difference from D63432/r365015 is that this patch does not place
SHF_STRINGS sections with different alignments into the same
MergeSyntheticSection. Doing that would:
(1) create unnecessary padding and thus waste space.
Add a test tail-merge-string-align2.s to check no extra padding is created.
(2) make some input sections unaligned when tail merge (-O2) is enabled.
The alignment of MergeTailAlignment::Builder was out of sync in D63432.
MOVAPS on such unaligned strings can raise SIGSEGV.
This should fix PR42289: the Linux kernel has a use case that input
files have .rodata.cst32 sections with different alignments. The
expectation (and what ld.bfd and gold do) is that in the -r link, there
is only one .rodata.cst32 (SHF_MERGE sections with different alignments
can be combined), but lld currently creates one for each different
alignment.
The current merging strategy:
1) Group SHF_MERGE sections by (name, sh_flags, sh_entsize and
sh_addralign). Merging is performed among a group, even if -O0 is specified.
2) Create one output section for each group. This is a special case in
addInputSec().
This patch changes 1) to:
1) Group SHF_MERGE sections by (name, sh_flags, sh_entsize).
Merging is performed among a group, even if -O0 is specified.
We will thus create just one .rodata.cst32 . This also improves merging
efficiency when sections with the same name but different alignments are
combined.
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D64200
llvm-svn: 365139
If %t1.o has a weak reference on foo, and %t2.so has a non-weak
reference on foo: `ld.lld %t1.o %t2.so -o %t`
We incorrectly set the binding of the undefined foo to STB_GLOBAL.
Fix this by ignoring undefined symbols in a SharedFile for Undefined and
SharedSymbol.
This fixes the binding of pthread_once when the program links against
both librt.so and libpthread.so
```
a.o: STB_WEAK reference to pthread_once
librt.so: STB_GLOBAL reference to pthread_once # should be ignored
libstdc++.so: STB_WEAK reference to pthread_once # should be ignored
libgcc_s.so.1: STB_WEAK reference to pthread_once # should be ignored
```
The STB_GLOBAL pthread_once issue (not fixed by D63974) can cause a link error when the result
DSO is used to link another DSO with -z defs if -lpthread is not specified. (libstdc++.so.6 not having a dependency on libpthread.so is a really nasty hack...)
We happened to create a weak undef before D63974 because libgcc_s.so.1
was linked the last and it changed the binding again to weak.
Reviewed By: ruiu
Differential Revision: https://reviews.llvm.org/D64136
llvm-svn: 365129
Summary:
Adds `--passive-segments` and `--active-segments` flags to control
what kind of segments are emitted. For now the default is always
to emit active segments so this is not a breaking change, but in
the future the default will be changed to passive segments when
shared memory is requested and active segments otherwise. When
passive segments are emitted, corresponding memory.init and
data.drop instructions are emitted in a `__wasm_init_memory`
function that is automatically called at the beginning of
`__wasm_call_ctors`.
Reviewers: sbc100, aheejin, dschuff
Subscribers: azakai, dschuff, jgravelle-google, sunfish, jfb, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D59343
llvm-svn: 365088
The referenced symbol is expected to point to an R_RISCV_*_HI20
relocation. An absolute symbol has no associated section, therefore
there cannot be a matching R_RISCV_*_HI20.
This fixes the crash reported by PR42038. For reference, ld.bfd errors:
(.init+0x4): dangerous relocation: %pcrel_lo missing matching %pcrel_hi
Differential Revision: https://reviews.llvm.org/D63273
llvm-svn: 365049
This reverts r365015.
David Zarzycki reported this change broke stage2 and stage3 tests. The
root cause is still not very clear, but I guess some SHF_MERGE sections
with the same name have different alignments. They were not merged
before but were merged after r365015.
Something that assumes address uniqueness of such mergeable data caused
the bug.
llvm-svn: 365048
gcc may generate .debug_info/.debug_aranges/.debug_line/etc that are
relocated by R_RISCV_ADD*/R_RISCV_SUB* pairs.
Allow R_RISCV_ADD in non-SHF_ALLOC section to fix link errors like:
ld.lld: error: print.c:(.debug_frame+0x60): has non-ABS relocation R_RISCV_ADD64 against symbol '.L0 '
Differential Revision: https://reviews.llvm.org/D63259
llvm-svn: 365035
This should fix PR42289: the Linux kernel has a use case that input
files have .rodata.cst32 sections with different alignments. The
expectation (and what ld.bfd and gold do) is that in the -r link, there
is only one .rodata.cst32 (SHF_MERGE sections with different alignments
can be combined), but lld currently creates one for each different
alignment.
The current merging strategy:
1) Group SHF_MERGE sections by (name, sh_flags, sh_entsize and
sh_addralign). String merging is performed among a group, even if -O0 is specified.
2) Create one output section for each group. This is a special case in
addInputSec().
This patch changes 1) to:
1) Group SHF_MERGE sections by (name, sh_flags, sh_entsize).
String merging is performed among a group, even if -O0 is specified.
We will thus create just one .rodata.cst32 . This also improves merging
efficiency when sections with the same name but different alignments are
combined.
Reviewed By: ruiu
Differential Revision: https://reviews.llvm.org/D63432
llvm-svn: 365015
This matches the wasm lld and GNU ld behavior.
The ELF linker has special handling for bitcode archives but if that
doesn't kick in we probably want to error out rather than silently
ignore the library.
Differential Revision: https://reviews.llvm.org/D63781
llvm-svn: 364998
Add Triple::riscv64 and Triple::riscv32 to getBitcodeMachineKind for get right
e_machine during LTO.
Reviewed By: ruiu, MaskRay
Differential Revision: https://reviews.llvm.org/D52165
llvm-svn: 364996
Fixes PR42442
t.o has a STB_GLOBAL undef ref to f
t2.so has a STB_WEAK undef ref to f
t1.so defines f
ld.lld t.o t1.so t2.so currently sets the binding of `f` to STB_WEAK.
This is not correct because there exists a STB_GLOBAL undef ref from a
regular object. The problem is that resolveUndefined() doesn't check
if the undef ref is seen for the first time:
if (isShared() || isLazy() || (isUndefined() && Other.Binding != STB_WEAK))
Binding = Other.Binding;
The isShared() condition should be `isShared() && !Referenced`
where Referenced is set to true after an undef ref is seen.
In practice, when linking a pthread program with glibc:
// a.o
#include <pthread.h>
pthread_mutex_t mu = PTHREAD_MUTEX_INITIALIZER;
int main() { pthread_mutex_unlock(&mu); }
{clang,gcc} -fuse-ld=lld a.o -lpthread # libpthread.so is linked before libgcc_s.so.1
The weak undef pthread_mutex_unlock in libgcc_s.so.1 makes the result
weak, which diverges from GNU linkers where STB_DEFAULT is used:
23: 0000000000000000 0 FUNC WEAK DEFAULT UND pthread_mutex_lock
(Note, if -pthread is used instead, libpthread.so will be linked **after**
libgcc_s.so.1 . lld sets the binding to the expected STB_GLOBAL)
Similar linking sequences (ld.lld t.o t1.so t2.so) appear to be used by
Go, which cause a build error https://github.com/golang/go/issues/31912.
Reviewed By: grimar, ruiu
Differential Revision: https://reviews.llvm.org/D63974
llvm-svn: 364913
RISC-V psABI doesn't specify TLS relaxation. It can be handled the same
way as we handle ARM TLS. RISC-V TLS is even simpler because GD/LD use
the same relocation type.
Reviewed By: jrtc27, ruiu
Differential Revision: https://reviews.llvm.org/D63220
llvm-svn: 364813
* Handle initial relocation types: R_RISCV_CALL_PLT and R_RISCV_GOT_HI20.
* Produce dynamic relocation types: R_RISCV_COPY, R_RISCV_RELATIVE, R_RISCV_JUMP_SLOT.
* Define SymbolRel as R_RISCV_{32,64}
* Generate PLT header: it is used by lazy binding PLT in glibc.
* R_RISCV_CALL is changed from R_PC to R_PC_PLT. If the target symbol is preemptable, this will suppress an unnecessary "canonical PLT".
This behavior is different from ld.bfd but it is agreed the current lld behavior is favored.
I have received positive responses from the binutils maintainer that the ABI/binutils implementation can be improved, see:
https://github.com/riscv/riscv-elf-psabi-doc/issues/98https://sourceware.org/bugzilla/show_bug.cgi?id=24685
Many -no-pie/-pie/-shared programs linked against musl or glibc should work with this patch.
Reviewed By: jrtc27
Differential Revision: https://reviews.llvm.org/D63076
llvm-svn: 364812
GNU windres, and MS cvtres (unless the /readonly option is passed)
produce read-write .rsrc sections, when creating resource object files.
This caused the sections to not be added to the precreated RsrcSec,
and therefore not be added to the data directory.
Differential Revision: https://reviews.llvm.org/D63837
llvm-svn: 364660
If .rela.plt is mentioned in a linker script, it might be preserved
even if it is empty. In that case, LLD created DT_JMPREL and DT_PLTGOT
dynamic tags. When the tags exist, a dynamic loader writes values into
reserved slots in .got.plt to support lazy symbol resolution.
The problem is that, in fact, the linker has not reserved that space,
and the writing may occur into the memory allocated for something else.
Differential Revision: https://reviews.llvm.org/D63869
llvm-svn: 364639
Summary:
This is needed for address sanitizer on Emscripten. As everything in
memory starts at the value passed to --global-base, everything before
that can be used as shadow memory.
This symbol is added so that the library for the ASan runtime can know
where the shadow memory ends and real memory begins.
This is split from D63742.
Reviewers: tlively, aheejin, sbc100
Subscribers: sunfish, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63833
llvm-svn: 364467
This restores r361830 "[ELF] Error on relocations to STT_SECTION symbols if the sections were discarded"
and dependent commits (r362218, r362497) which were reverted by r364321, with a fix of a --gdb-index issue.
.rela.debug_ranges contains relocations of range list entries:
// start address of a range list entry
// old: 0; after r361830: 0
00000000000033a0 R_X86_64_64 .text._ZN2v88internal7Isolate7factoryEv + 0
// end address of a range list entry
// old: 0xe; after r361830: 0
00000000000033a8 R_X86_64_64 .text._ZN2v88internal7Isolate7factoryEv + e
If both start and end addresses of a range list entry resolve to 0,
DWARFDebugRangeList::isEndOfListEntry() will return true, then the
.debug_range decoding loop will terminate prematurely:
while (true) {
decode StartAddress
decode EndAddress
if (Entry.isEndOfListEntry()) // prematurely
break;
Entries.push_back(Entry);
}
In lld/ELF/SyntheticSections.cpp, readAddressAreas() will read
incomplete address ranges and the resulting .gdb_index will be
incomplete. For files that gdb hasn't loaded their debug info, gdb uses
.gdb_index to map addresses to CUs. The absent entries make gdb fail to
symbolize some addresses.
To address this issue, we simply allow relocations to undefined symbols
in DWARF.cpp:findAux() and let RelocationResolver resolve them.
This patch should fix:
[1] http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20190603/659848.html
[2] https://bugs.chromium.org/p/chromium/issues/detail?id=978067
llvm-svn: 364391
Summary:
Before:
```
wasm-ld: error: Relocations not in offset order
```
After
```
wasm-ld: error: While processing `libjulia.so`: Relocations not in offset order
```
At least this way you get to find out which input file is malformed.
Reviewers: sbc100
Differential Revision: https://reviews.llvm.org/D63694
llvm-svn: 364368
Summary:
The list of relocations with addend in lld was missing `R_WASM_MEMORY_ADDR_REL_SLEB`,
causing `wasm-ld` to generate corrupted output. This fixes that problem and while
we're at it pulls the list of such relocations into the Wasm.h header, to avoid
duplicating it in multiple places.
Reviewers: sbc100
Differential Revision: https://reviews.llvm.org/D63696
llvm-svn: 364367
This is fairly common with wasm since GNU ar (most likely the system ar)
doesn't support the wasm object format so user who don't override AR
will end up with archives without an index. We don't want to silently
ignore this issue.
In the future we could choose to instead behave like the ELF backend and
read the symbols from each object file in the archive if they are all of
the same type. However, error'ing out seem like a conservative approach
for now.
Fixes: PR42376
Differential Revision: https://reviews.llvm.org/D63739
llvm-svn: 364338
(In effect, reverting "[ELF] Error on relocations to STT_SECTION symbols if the sections were discarded".)
It caused debug info problems in LibreOffice [1] and Chromium/V8 [2].
Reverting until those can be fixed.
It also reverts r362497 "STT_SECTION symbol should be defined" on .eh_frame, .debug*, .zdebug* and .gcc_except_table"
which was landed as a follow-up to the above.
> With -r or --emit-relocs, we warn `STT_SECTION symbol should be defined`
> on relocations to discarded section symbol. This was added as an error
> in rLLD319404, but was not so effective before D61583 (it turned the
> error to a warning).
>
> Relocations from .eh_frame .debug* .zdebug* .gcc_except_table to
> discarded .text are very common and somewhat expected. Don't warn/error
> on them. As a reference, ld.bfd has a similar logic in
> _bfd_elf_default_action_discarded() to allow these cases.
>
> Delete invalid-undef-section-symbol.test because what it intended to
> check is now covered by the updated comdat-discarded-reloc.s
>
> Delete relocatable-eh-frame.s because we allow relocations from
> .eh_frame as a special case now.
And finally it reverts r362218 "[ELF] Replace a dead test in getSymVA() with assert()"
as that also depended on the main change reverted here.
> Symbols relative to discarded comdat sections are Undefined instead of
> Defined now (after D59649 and D61583). The `== &InputSection::Discarded`
> test becomes dead. I cannot find a test related to this behavior.
[1] http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20190603/659848.html
[2] https://bugs.chromium.org/p/chromium/issues/detail?id=978067
llvm-svn: 364321
lld/coff already deduplicated undefined symbols on a TU level: It would
group all references to a symbol from a single TU. This makes it so that
references from all TUs to a single symbol are grouped together.
Since lld/coff almost did what I thought it did already, the patch is
much smaller than the elf version. The only not local change is that
getSymbolLocations() now returns a vector<string> instead of a string,
so that the undefined symbol reporting code can know how many references
to a symbol exist in a given TU.
Fixes PR42260 for lld/coff.
Differential Revision: https://reviews.llvm.org/D63646
llvm-svn: 364285
r360841 introduced CommonSymbol class. An unintended behavioral change
introduced by that change was that common symbols are not internalized
by LTO under some condition. This patch fixes that issue.
The issue occurred under the following condition:
1. There exists a common symbol
2. At least one DSO is given to lld or -pie is used
If the above conditions are met, Symbol::includeInDynsym() returned a
wrong value for a common symbol.
Fixes https://bugs.llvm.org/show_bug.cgi?id=41978
Differential Revision: https://reviews.llvm.org/D63752
llvm-svn: 364273
Similar to R_AARCH64_ABS32, R_PPC64_ADDR32 can represent either a signed
value or unsigned value, thus we should use `[-2**(n-1), 2**n)` instead of
`[-2**(n-1), 2**(n-1))` to check overflows.
The issue manifests as a bogus linker error when linking the powerpc64le Linux kernel.
The new behavior is compatible with ld.bfd's complain_overflow_bitfield.
The upper bound of the error message is not correct. Fix it as well.
The changes to R_PPC_ADDR16, R_PPC64_ADDR16, R_X86_64_8 and R_X86_64_16 are similar.
Reviewed By: ruiu
Differential Revision: https://reviews.llvm.org/D63690
llvm-svn: 364164
Summary:
Our rule to create R_*_RELATIVE for absolute relocation types were
loose. D63121 made it stricter but it failed to create R_*_RELATIVE for
R_ARM_TARGET1 and R_PPC64_TOC. rLLD363236 worked around that by
reinstating the original behavior for ARM and PPC64.
This patch is an attempt to simplify the logic.
Note, in ld.bfd, R_ARM_TARGET2 --target2=abs also creates
R_ARM_RELATIVE. This seems a very uncommon scenario (moreover,
--target2=got-rel is the default), so I do not implement any logic
related to it.
Also, delete R_AARCH64_ABS32 from AArch64::getDynRel. We don't have
working ILP32 support yet. Allowing it would create an incorrect
R_AARCH64_RELATIVE.
For MIPS, the (if SymbolRel, then RelativeRel) code is to keep its
behavior unchanged.
Note, in ppc64-abs64-dyn.s, R_PPC64_TOC gets an incorrect addend because
computeAddend() doesn't compute the correct address. We seem to have the
wrong behavior for a long time. The important thing seems that a dynamic
relocation R_PPC64_TOC should not be created as the dynamic loader will
error R_PPC64_TOC is not supported.
Reviewers: atanasyan, grimar, peter.smith, ruiu, sfertile, espindola
Reviewed By: ruiu
Differential Revision: https://reviews.llvm.org/D63383
llvm-svn: 363928
Some versions of the Visual C++ 2015 runtime have line tables with the
subsection kind of 0x800000F2. In cvinfo.h, 0x80000000 is documented to
be DEBUG_S_IGNORE. This appears to implement the intended behavior.
llvm-svn: 363724
Use -fsave-optimization-record=<format> to specify a different format
than the default, which is YAML.
For now, only YAML is supported.
llvm-svn: 363573
This matches how it is done for .xdata and .pdata already.
On i386, the symbol name in the section name suffix does not contain
the extra underscore prefix.
This is one part of a fix for PR42217.
Differential Revision: https://reviews.llvm.org/D63350
llvm-svn: 363456
In processRelocAux(), our handling of 1) link-time constant and 2) weak
undef is the same, so put them together to simplify the logic.
This moves the weak undef code around. The result is that: in a writable
section (or -z notext), we will no longer emit dynamic relocations for
weak undefined symbols.
The new behavior seems to match GNU linkers, and improves consistency
with the case of a readonly section.
The condition `!Config->Shared` was there probably because it is common
for a -shared link not to specify full dependencies. Keep it now but we
may revisit the decision in the future.
gABI says:
> The behavior of weak symbols in areas not specified by this document is
> implementation defined. Weak symbols are intended primarily for use in
> system software. Applications using weak symbols are unreliable since
> changes in the runtime environment might cause the execution to fail.
Reviewed By: ruiu
Differential Revision: https://reviews.llvm.org/D63003
llvm-svn: 363399
This patch adds new command line option `--undefined-glob` to lld.
That option is a variant of `--undefined` but accepts wildcard
patterns so that all symbols that match with a given pattern are
handled as if they were given by `-u`.
`-u foo` is to force resolve symbol foo if foo is not a defined symbol
and there's a static archive that contains a definition of symbol foo.
Now, you can specify a wildcard pattern as an argument for `--undefined-glob`.
So, if you want to include all JNI symbols (which start with "Java_"), you
can do that by passing `--undefined-glob "Java_*"` to the linker, for example.
In this patch, I use the same glob pattern matcher as the version script
processor is using, so it does not only support `*` but also `?` and `[...]`.
Differential Revision: https://reviews.llvm.org/D63244
llvm-svn: 363396
If .sdata is absent, linker synthesized __global_pointer$ gets a section index of SHN_ABS.
(ld.bfd has a similar issue: binutils PR24678)
Scrt1.o may use `lla gp, __global_pointer$` to reference the symbol PC
relatively. In -pie/-shared mode, lld complains if a PC relative
relocation references an absolute symbol (SHN_ABS) but ld.bfd doesn't:
ld.lld: error: relocation R_RISCV_PCREL_HI20 cannot refer to lute symbol: __global_pointer$
Let the reference of __global_pointer$ to force creation of .sdata to
fix the problem. This is similar to _GLOBAL_OFFSET_TABLE_, which forces
creation of .got or .got.plt .
Also, change the visibility from STV_HIDDEN to STV_DEFAULT and don't
define the symbol for -shared. This matches ld.bfd, though I don't
understand why it uses STV_DEFAULT.
Reviewed By: ruiu, jrtc27
Differential Revision: https://reviews.llvm.org/D63132
llvm-svn: 363351
PDBs may not necessarily contain an IPI stream. Handle this case
gracefully.
The test case was verified to work with MS link.exe.
Patch by Vladimir Panteleev, with a small simplification
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D63178
llvm-svn: 363213
An unrecognized signature (magic) at the beginning of a debug section
should not be a fatal error; it only means that the debug information
is in a format that is not supported by LLD. This can be due to it
being in CodeView versions 3 or earlier. These can occur in old import
libraries from legacy SDKs.
The test case was verified to work with MS link.exe.
Patch by Vladimir Panteleev!
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D63177
llvm-svn: 363212
R_RISCV_{ADD,SET,SUB}* are used for local label computation.
Add a new RelExpr member R_RISCV_ADD to represent them.
R_RISCV_ADD is treated as a link-time constant because otherwise
R_RISCV_{ADD,SET,SUB}* are not allowed in -pie/-shared mode.
In glibc Scrt1.o, .rela.eh_frame contains such relocations.
Because .eh_frame is not writable, we get this error:
ld.lld: error: can't create dynamic relocation R_RISCV_ADD32 against symbol: .L0 in readonly segment; recompil object files with -fPIC or pass '-Wl,-z,notext' to allow text relocations in the output
>>> defined in ..../riscv64-linux-gnu/lib/Scrt1.o
With D63076 and this patch, I can run -pie/-shared programs linked against glibc.
Note llvm-mc cannot currently produce R_RISCV_SET* so they are not tested.
Reviewed By: ruiu
Differential Revision: https://reviews.llvm.org/D63183
llvm-svn: 363128
Summary:
clang (as of 2019-06-12) / gcc (as of 8.2.1) PPC64 may emit a .rela.toc
which references an embedded switch table in a discarded .rodata/.text
section. The .toc and the .rela.toc are incorrectly not placed in the
comdat.
Technically a relocation from outside the group is not allowed by the ELF spec:
> A symbol table entry with STB_LOCAL binding that is defined relative
> to one of a group's sections, and that is contained in a symbol table
> section that is not part of the group, must be discarded if the group
> members are discarded. References to this symbol table entry from
> outside the group are not allowed.
Don't report errors to work around the bug.
This should fix the ppc64le-lld-multistage-test bot while linking llvm-tblgen:
ld.lld: error: relocation refers to a discarded section: .rodata._ZNK4llvm3MVT13getSizeInBitsEv
>>> defined in utils/TableGen/CMakeFiles/llvm-tblgen.dir/CodeGenRegisters.cpp.o
>>> referenced by CodeGenRegisters.cpp
>>> utils/TableGen/CMakeFiles/llvm-tblgen.dir/CodeGenRegisters.cpp.o:(.toc+0x0)
Some other PPC specific sections may have similar problems. We can blacklist more
section names when problems occur.
// A simple program that reproduces the bug.
// Note .rela.toc (outside the group) references a section symbol (STB_LOCAL) in a group.
void puts(const char *);
struct A {
void foo(int a) {
switch (a) {
case 0: puts("0"); break;
case 1: puts("1"); puts("1"); break;
case 2: puts("2"); break;
case 3: puts("3"); puts("4"); break;
case 4: puts("4"); break;
case 5: puts("5"); puts("5"); break;
case 6: puts("6"); break;
}
}
int a;
};
void foo(A x) { x.foo(x.a); }
Reviewers: ruiu, sfertile, espindola
Reviewed By: ruiu
Subscribers: emaste, nemanjai, arichardson, kbarton, jsji, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63182
llvm-svn: 363126
Summary: Deduplicate S_CONSTANTS when linking, if they have the same value.
Reviewers: rnk
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63151
llvm-svn: 363089
Users are exepcted to pass all .res files to the linker, which then
merges all the resource in all .res files into a tree structure and then
converts the final tree structure to a .obj file with .rsrc$01 and
.rsrc$02 sections and then links that.
If the user instead passes several .obj files containing such resources,
the correct thing to do would be to have custom code to merge the trees
in the resource sections instead of doing normal section merging -- but
link.exe rejects if multiple resource obj files are passed in with
LNK4078, so let lld-link do that too instead of silently writing broken
.rsrc sections in that case.
The only real way to run into this is if users manually convert .res
files to .obj files by running cvtres and then handing the resulting
.obj files to lld-link instead, which in practice likely never happens.
(lld-link is slightly stricter than link.exe now: If link.exe is passed
one .obj file created by cvtres, and a .res file, for some reason it
just emits a warning instead of an error and outputs strange looking
data. lld-link now errors out on mixed input like this.)
One way users could accidentally run into this is the following
scenario: If a .res file is passed to lib.exe, then lib.exe calls
cvtres.exe on the .res file before putting it in the output .lib.
(llvm-lib currently doesn't do this.)
link.exe's /wholearchive seems to only add obj files referenced from the
static library index, but lld-link current really adds all files in the
archive. So if lld-link /wholearchive is used with .lib files produced
by lib.exe and .res files were among the files handed to lib.exe, we
previously silently produced invalid output, but now we error out.
link.exe's /wholearchive semantics on the other hand mean that it
wouldn't load the resource object files from the .lib file at all.
Since this scenario is probably still an unlikely corner case,
the difference in behavior here seems fine -- and lld-link might have to
change to use link.exe's /wholearchive semantics in the future anyways.
Vaguely related to PR42180.
Differential Revision: https://reviews.llvm.org/D63109
llvm-svn: 363078
So that R_RISCV_PCREL_LO12_[IS] are considered as link-time constants in
-pie mode, otherwise there are bogus errors:
ld.lld: error: can't create dynamic relocation R_RISCV_PCREL_LO12_I against symbol: .L0 in readonly segment; recompile object files with -fPIC or pass '-Wl,-z,notext' to allow text relocations in the output
Reviewed By: ruiu
Differential Revision: https://reviews.llvm.org/D63123
llvm-svn: 363064
The current rule is loose: `!Sym.IsPreemptible || Expr == R_GOT`.
When the symbol is non-preemptable, this allows absolute relocation
types with smaller numbers of bits, e.g. R_X86_64_{8,16,32}. They are
disallowed by ld.bfd and gold, e.g.
ld.bfd: a.o: relocation R_X86_64_8 against `.text' can not be used when making a shared object; recompile with -fPIC
This patch:
a) Add TargetInfo::SymbolicRel to represent relocation types that resolve to a
symbol value (e.g. R_AARCH_ABS64, R_386_32, R_X86_64_64).
As a side benefit, we currently (ab)use GotRel (R_*_GLOB_DAT) to resolve
GOT slots that are link-time constants. Since we now use Target->SymbolRel
to do the job, we can remove R_*_GLOB_DAT from relocateOne() for all targets.
R_*_GLOB_DAT cannot be used as static relocation types.
b) Change the condition to `!Sym.IsPreemptible && Type != Target->SymbolicRel || Expr == R_GOT`.
Some tests are caught by the improved error checking (ld.bfd/gold also
issue errors on them). Many misuse .long where .quad should be used
instead.
Reviewed By: ruiu
Differential Revision: https://reviews.llvm.org/D63121
llvm-svn: 363059
The previous name "%lib" doesn't trigger any actual replacement. It
creates the file "./tools/lld/test/ELF/%lib.o" in the test directory.
llvm-svn: 362988
Fix buildbot failure on native AArch64 buildbot that does not have X86
backend compiled in.
Differential Revision: https://reviews.llvm.org/D63071
llvm-svn: 362926
This is implemented by the lld-link option -include:, just like
--require-defined. Contrary to --require-defined, the -u/--undefined
option allows the symbol to remain undefined in the end.
This should fix PR42121.
Differential Revision: https://reviews.llvm.org/D62876
llvm-svn: 362882
This works like /include, but is not fatal if the requested symbol
wasn't found. This allows implementing the GNU ld option -u.
Differential Revision: https://reviews.llvm.org/D62976
llvm-svn: 362881
Summary:
When handling exports from the command line or from .def files, the
linker does a "fuzzy" string lookup to allow finding mangled symbols.
However, when the symbol is re-exported under a new name, the linker has
to transfer the decorations from the exported symbol over to the new
name. This is implemented by taking the mangled symbol that was found in
the object and replacing the original symbol name with the export name.
Before this patch, LLD implemented the fuzzy search by adding an
undefined symbol with the unmangled name, and then during symbol
resolution, checking if similar mangled symbols had been added after the
last round of symbol resolution. If so, LLD makes the original symbol a
weak alias of the mangled symbol. Later, to get the original symbol
name, LLD would look through the weak alias and forward it on to the
import library writer, which copies the symbol decorations. This
approach doesn't work when bar is itself a weak alias, as is the case in
asan. It's especially bad when the aliasee of bar contains the string
"bar", consider "bar_default". In this case, we would end up exporting
the symbol "foo_default" when we should've exported just "foo".
To fix this, don't look through weak aliases to find the mangled name.
Save the mangled name earlier during fuzzy symbol lookup.
Fixes PR42074
Reviewers: mstorsjo, ruiu
Subscribers: thakis, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62984
llvm-svn: 362849
We create several types of synthetic sections for loadable partitions, including:
- The dynamic symbol table. This allows code outside of the loadable partitions
to find entry points with dlsym.
- Creating a dynamic symbol table also requires the creation of several other
synthetic sections for the partition, such as the dynamic table and hash table
sections.
- The partition's ELF header is represented as a synthetic section in the
combined output file, and will be used by llvm-objcopy to extract partitions.
Differential Revision: https://reviews.llvm.org/D62350
llvm-svn: 362819
Branch Target Identification (BTI) and Pointer Authentication (PAC) are
architecture features introduced in v8.5a and 8.3a respectively. The new
instructions have been added in the hint space so that binaries take
advantage of support where it exists yet still run on older hardware. The
impact of each feature is:
BTI: For executable pages that have been guarded, all indirect branches
must have a destination that is a BTI instruction of the appropriate type.
For the static linker, this means that PLT entries must have a "BTI c" as
the first instruction in the sequence. BTI is an all or nothing
property for a link unit, any indirect branch not landing on a valid
destination will cause a Branch Target Exception.
PAC: The dynamic loader encodes with PACIA the address of the destination
that the PLT entry will load from the .plt.got, placing the result in a
subset of the top-bits that are not valid virtual addresses. The PLT entry
may authenticate these top-bits using the AUTIA instruction before
branching to the destination. Use of PAC in PLT sequences is a contract
between the dynamic loader and the static linker, it is independent of
whether the relocatable objects use PAC.
BTI and PAC are independent features that can be combined. So we can have
several combinations of PLT:
- Standard with no BTI or PAC
- BTI PLT with "BTI c" as first instruction.
- PAC PLT with "AUTIA1716" before the indirect branch to X17.
- BTIPAC PLT with "BTI c" as first instruction and "AUTIA1716" before the
first indirect branch to X17.
The use of BTI and PAC in relocatable object files are encoded by feature
bits in the .note.gnu.property section in a similar way to Intel CET. There
is one AArch64 specific program property GNU_PROPERTY_AARCH64_FEATURE_1_AND
and two target feature bits defined:
- GNU_PROPERTY_AARCH64_FEATURE_1_BTI
-- All executable sections are compatible with BTI.
- GNU_PROPERTY_AARCH64_FEATURE_1_PAC
-- All executable sections have return address signing enabled.
Due to the properties of FEATURE_1_AND the static linker can tell when all
input relocatable objects have the BTI and PAC feature bits set. The static
linker uses this to enable the appropriate PLT sequence.
Neither -> standard PLT
GNU_PROPERTY_AARCH64_FEATURE_1_BTI -> BTI PLT
GNU_PROPERTY_AARCH64_FEATURE_1_PAC -> PAC PLT
Both properties -> BTIPAC PLT
In addition to the .note.gnu.properties there are two new command line
options:
--force-bti : Act as if all relocatable inputs had
GNU_PROPERTY_AARCH64_FEATURE_1_BTI and warn for every relocatable object
that does not.
--pac-plt : Act as if all relocatable inputs had
GNU_PROPERTY_AARCH64_FEATURE_1_PAC. As PAC is a contract between the loader
and static linker no warning is given if it is not present in an input.
Two processor specific dynamic tags are used to communicate that a non
standard PLT sequence is being used.
DTI_AARCH64_BTI_PLT and DTI_AARCH64_BTI_PAC.
Differential Revision: https://reviews.llvm.org/D62609
llvm-svn: 362793
When a function is excluded via comdat we shouldn't add it to the
final list of init functions.
Differential Revision: https://reviews.llvm.org/D62983
llvm-svn: 362769
Many -static/-no-pie/-shared/-pie applications linked against glibc or musl
should work with this patch. This also helps FreeBSD PowerPC64 to migrate
their lib32 (PR40888).
* Fix default image base and max page size.
* Support new-style Secure PLT (see below). Old-style BSS PLT is not
implemented, so it is not suitable for FreeBSD rtld now because it doesn't
support Secure PLT yet.
* Support more initial relocation types:
R_PPC_ADDR32, R_PPC_REL16*, R_PPC_LOCAL24PC, R_PPC_PLTREL24, and R_PPC_GOT16.
The addend of R_PPC_PLTREL24 is special: it decides the call stub PLT type
but it should be ignored for the computation of target symbol VA.
* Support GNU ifunc
* Support .glink used for lazy PLT resolution in glibc
* Add a new thunk type: PPC32PltCallStub that is similar to PPC64PltCallStub.
It is used by R_PPC_REL24 and R_PPC_PLTREL24.
A PLT stub used in -fPIE/-fPIC usually loads an address relative to
.got2+0x8000 (-fpie/-fpic code uses _GLOBAL_OFFSET_TABLE_ relative
addresses).
Two .got2 sections in two object files have different addresses, thus a PLT stub
can't be shared by two object files. To handle this incompatibility,
change the parameters of Thunk::isCompatibleWith to
`const InputSection &, const Relocation &`.
PowerPC psABI specified an old-style .plt (BSS PLT) that is both
writable and executable. Linkers don't make separate RW- and RWE segments,
which causes all initially writable memory (think .data) executable.
This is a big security concern so a new PLT scheme (secure PLT) was developed to
address the security issue.
TLS will be implemented in D62940.
glibc older than ~2012 requires .rela.dyn to include .rela.plt, it can
not handle the DT_RELA+DT_RELASZ == DT_JMPREL case correctly. A hack
(not included in this patch) in LinkerScript.cpp addOrphanSections() to
work around the issue:
if (Config->EMachine == EM_PPC) {
// Older glibc assumes .rela.dyn includes .rela.plt
Add(In.RelaDyn);
if (In.RelaPlt->isLive() && !In.RelaPlt->Parent)
In.RelaDyn->getParent()->addSection(In.RelaPlt);
}
Reviewed By: ruiu
Differential Revision: https://reviews.llvm.org/D62464
llvm-svn: 362721
We were not previously testing the comdat exclusion in bitcode objects
because we were linking two copies of the .bc file and the
`linkonce_odr` linkage type was removing the duplicate `_start` at
the LTO stage.
Now we link an bitcode and non-bitcode version both of which contains a
copy of _start. We link them in both orders, which means this test will
fail if comdat exclusion is not working correctly in bitcode parsing.
Differential Revision: https://reviews.llvm.org/D62923
llvm-svn: 362650
With r362638, llc doesn't support -relocation-model=pic with non-Emscripten
triples. Update these tests in lld which use -relocation-model=pic to also
use Emscripten triples.
llvm-svn: 362645
Although many relocatable objects will have a single
GNU_PROPERTY_X86_FEATURE_1_AND in the .note.gnu.property section it is
permissible to have more than one, and there are tests in ld.bfd that use
it. The behavior that ld.bfd follows is to set the feature bit for a
relocatable object if any of the GNU_PROPERTY_X86_FEATURE_1_AND
have the feature bit set.
Differential Revision: https://reviews.llvm.org/D62862
llvm-svn: 362591
The age field is only there to say how many times an OBJ or a PDB was incrementally linked. It shouldn't be used to validate the link between the OBJ and the PDB.
Differential Revision: https://reviews.llvm.org/D62837
llvm-svn: 362572
Summary:
With -r or --emit-relocs, we warn `STT_SECTION symbol should be defined`
on relocations to discarded section symbol. This was added as an error
in rLLD319404, but was not so effective before D61583 (it turned the
error to a warning).
Relocations from .eh_frame .debug* .zdebug* .gcc_except_table to
discarded .text are very common and somewhat expected. Don't warn/error
on them. As a reference, ld.bfd has a similar logic in
_bfd_elf_default_action_discarded() to allow these cases.
Delete invalid-undef-section-symbol.test because what it intended to
check is now covered by the updated comdat-discarded-reloc.s
Delete relocatable-eh-frame.s because we allow relocations from
.eh_frame as a special case now.
Reviewers: grimar, phosek, ruiu, espindola
Reviewed By: ruiu
Subscribers: emaste, arichardson, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62840
llvm-svn: 362497
Summary:
- Fixes inline call frame line table display in windbg.
- Improve llvm-pdbutil to dump extra file ids.
- Warn on unknown subsections so we don't have this kind of bug in the
future.
Reviewers: inglorion, akhuang, aganea
Subscribers: eraman, zturner, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62701
llvm-svn: 362429
We need to have all input files ready before doing debuginfo type merging.
This patch is moving the late PDB type server discovery much earlier in the process, when the explicit inputs (OBJs, LIBs) are loaded.
The short term goal is to parallelize type merging.
Differential Revision: https://reviews.llvm.org/D60095
llvm-svn: 362393
The following abstract relocation types (RelExpr) are PPC64 ELFv2 ABI specific,
not used by PPC32. So rename them to prevent confusion when the PPC32 port is improved.
* R_PPC_CALL R_PPC_CALL_PLT:
R_PPC_CALL_PLT represents R_PPC64_REL14 and R_PPC64_REL24.
If the function is not preemptable, R_PPC_CALL_PLT can be optimized to R_PPC_CALL:
the formula adjusts the symbol VA from the global entry point to the local entry point.
* R_PPC_TOC: represents R_PPC64_TOC. We don't have a test. Add one to ppc64-relocs.s
Rename it to R_PPC64_TOCBASE because `@tocbase` is the assembly form.
Reviewed By: ruiu
Differential Revision: https://reviews.llvm.org/D62800
llvm-svn: 362359
In ELF v2 ABI, R_PPC64_GOT_DTPREL16* are not relaxed.
This family of relocation types are used for variables outside of 2GiB
of the TLS block. 2 instructions cannot materialize a DTPREL offset that
is not 32-bit.
Reviewed By: ruiu
Differential Revision: https://reviews.llvm.org/D62737
llvm-svn: 362357
Fixes the remaining issue of PR41673 after D61186: with `/DISCARD/ { ... } :NONE`,
we may create an output section named `/DISCARD/`.
Note, if an input section is named `/DISCARD/`, ld.bfd discards it but
lld keeps it. It is probably not worth copying this behavior as it is unrealistic.
Reviewed By: ruiu
Differential Revision: https://reviews.llvm.org/D62768
llvm-svn: 362356
Martin Storsjo