This patch changes to make call_indirect explicitly refer to the
corresponding function table, residualizing TABLE_NUMBER relocs against
it.
With this change, wasm-ld now sees all references to tables, and can
link multiple tables.
Differential Revision: https://reviews.llvm.org/D90948
The commit 18aa0be36e changed the default GotBaseSymInGotPlt to true
for AArch64. This is different than binutils, where
_GLOBAL_OFFSET_TABLE_ points at the start or .got.
It seems to not intefere with current relocations used by LLVM. However
as indicated by PR#40357 [1] gcc generates R_AARCH64_LD64_GOTPAGE_LO15
for -pie (in fact it also generated the relocation for -fpic).
This change is requires to correctly handle R_AARCH64_LD64_GOTPAGE_LO15
by lld from objects generated by gcc.
[1] https://bugs.llvm.org/show_bug.cgi?id=40357
This patch adds support to wasm-ld for linking multiple table references
together, in a manner similar to wasm globals. The indirect function
table is synthesized as needed.
To manage the transitional period in which the compiler doesn't yet
produce TABLE_NUMBER relocations and doesn't residualize table symbols,
the linker will detect object files which have table imports or
definitions, but no table symbols. In that case it will synthesize
symbols for the defined and imported tables.
As a change, relocatable objects are now written with table symbols,
which can cause symbol renumbering in some of the tests. If no object
file requires an indirect function table, none will be written to the
file. Note that for legacy ObjFile inputs, this test is conservative: as
we don't have relocs for each use of the indirecy function table, we
just assume that any incoming indirect function table should be
propagated to the output.
Differential Revision: https://reviews.llvm.org/D91870
On z/OS, the following error message is not matched correctly in lit tests. This patch updates the CHECK expression to match successfully.
```
EDC5129I No such file or directory.
```
Reviewed By: muiez
Differential Revision: https://reviews.llvm.org/D94239
This patch adds support to wasm-ld for linking multiple table references
together, in a manner similar to wasm globals. The indirect function
table is synthesized as needed.
To manage the transitional period in which the compiler doesn't yet
produce TABLE_NUMBER relocations and doesn't residualize table symbols,
the linker will detect object files which have table imports or
definitions, but no table symbols. In that case it will synthesize
symbols for the defined and imported tables.
As a change, relocatable objects are now written with table symbols,
which can cause symbol renumbering in some of the tests. If no object
file requires an indirect function table, none will be written to the
file. Note that for legacy ObjFile inputs, this test is conservative: as
we don't have relocs for each use of the indirecy function table, we
just assume that any incoming indirect function table should be
propagated to the output.
Differential Revision: https://reviews.llvm.org/D91870
When running in `-r/--relocatable` we output relocations but the
new TLS relocations type was missing from `ObjFile::calcNewAddend`
causing this combination of inputs/flags to crash the linker.
Also avoid creating tls variables in relocatable mode. These variables
are only needed when linking final executables.
Fixes: https://github.com/emscripten-core/emscripten/issues/12934
Fixes: PR48506
Differential Revision: https://reviews.llvm.org/D93554
Fixes PR48693: --emit-relocs keeps relocation sections. --gdb-index drops
.debug_gnu_pubnames and .debug_gnu_pubtypes but not their relocation sections.
This can cause a null pointer dereference in `getOutputSectionName`.
Also delete debug-gnu-pubnames.s which is covered by gdb-index.s
Reviewed By: grimar
Differential Revision: https://reviews.llvm.org/D94354
Fixes PR48681: after LTO, lto.tmp may reference a libcall symbol not in an IR
symbol table of any bitcode file. If such a symbol is defined in an archive
matched by a --exclude-libs, we don't correctly localize the symbol.
Add another `excludeLibs` after `compileBitcodeFiles` to localize such libcall
symbols. Unfortunately we have keep the existing one for D43126.
Using VER_NDX_LOCAL is an implementation detail of `--exclude-libs`, it does not
necessarily tie to the "localize" behavior. `local:` patterns in a version
script can be omitted.
The `symbol ... has undefined version ...` error should not be exempted.
Ideally we should error as GNU ld does. https://issuetracker.google.com/issues/73020933
Reviewed By: psmith
Differential Revision: https://reviews.llvm.org/D94280
Local values are constants or addresses that can't be folded into
the instruction that uses them. FastISel materializes these in a
"local value" area that always dominates the current insertion
point, to try to avoid materializing these values more than once
(per block).
https://reviews.llvm.org/D43093 added code to sink these local
value instructions to their first use, which has two beneficial
effects. One, it is likely to avoid some unnecessary spills and
reloads; two, it allows us to attach the debug location of the
user to the local value instruction. The latter effect can
improve the debugging experience for debuggers with a "set next
statement" feature, such as the Visual Studio debugger and PS4
debugger, because instructions to set up constants for a given
statement will be associated with the appropriate source line.
There are also some constants (primarily addresses) that could be
produced by no-op casts or GEP instructions; the main difference
from "local value" instructions is that these are values from
separate IR instructions, and therefore could have multiple users
across multiple basic blocks. D43093 avoided sinking these, even
though they were emitted to the same "local value" area as the
other instructions. The patch comment for D43093 states:
Local values may also be used by no-op casts, which adds the
register to the RegFixups table. Without reversing the RegFixups
map direction, we don't have enough information to sink these
instructions.
This patch undoes most of D43093, and instead flushes the local
value map after(*) every IR instruction, using that instruction's
debug location. This avoids sometimes incorrect locations used
previously, and emits instructions in a more natural order.
In addition, constants materialized due to PHI instructions are
not assigned a debug location immediately; instead, when the
local value map is flushed, if the first local value instruction
has no debug location, it is given the same location as the
first non-local-value-map instruction. This prevents PHIs
from introducing unattributed instructions, which would either
be implicitly attributed to the location for the preceding IR
instruction, or given line 0 if they are at the beginning of
a machine basic block. Neither of those consequences is good
for debugging.
This does mean materialized values are not re-used across IR
instruction boundaries; however, only about 5% of those values
were reused in an experimental self-build of clang.
(*) Actually, just prior to the next instruction. It seems like
it would be cleaner the other way, but I was having trouble
getting that to work.
This reapplies commits cf1c774d and dc35368c, and adds the
modification to PHI handling, which should avoid problems
with debugging under gdb.
Differential Revision: https://reviews.llvm.org/D91734
We were mishandling the case where both `__tbss` and `__thread_data` sections were
present.
TLVP relocations should be encoded as offsets from the start of `__thread_data`,
even if the symbol is actually located in `__thread_bss`. Previously, we were
writing the offset from the start of the containing section, which doesn't
really make sense since there's no way `tlv_get_addr()` can know which section a
given `tlv$init` symbol is in at runtime.
In addition, this patch ensures that we place `__thread_data` immediately before
`__thread_bss`. This is what ld64 does, likely for performance reasons. Zerofill
sections must also be at the end of their segments; we were already doing this,
but now we ensure that `__thread_bss` occurs before `__bss`, so that it's always
possible to have it contiguous with `__thread_data`.
Fixes llvm.org/PR48657.
Reviewed By: #lld-macho, thakis
Differential Revision: https://reviews.llvm.org/D94329
Before this patch, when using LLD with /DEBUG:GHASH and MSVC precomp.OBJ files, we had a bunch of:
lld-link: warning: S_[GL]PROC32ID record in blabla.obj refers to PDB item index 0x206ED1 which is not a LF[M]FUNC_ID record
This was caused by LF_FUNC_ID and LF_MFUNC_ID which didn't have correct mapping to the corresponding TPI records. The root issue was that the indexMapStorage was improperly re-assembled in UsePrecompSource::remapTpiWithGHashes.
After this patch, /DEBUG and /DEBUG:GHASH produce exactly the same debug infos in the PDB.
Differential Revision: https://reviews.llvm.org/D93732
A struct in C passed by value did not get debug information. Such values are currently
lowered to a Wasm local even in -O0 (not to an alloca like on other archs), which becomes
a Target Index operand (TI_LOCAL). The DWARF writing code was not emitting locations
in for TI's specifically if the location is a single range (not a list).
In addition, the ExplicitLocals pass which removes the ARGUMENT pseudo instructions did
not update the associated DBG_VALUEs, and couldn't even find these values since the code
assumed such instructions are adjacent, which is not the case here.
Also fixed asm printing of TIs needed by a test.
Differential Revision: https://reviews.llvm.org/D94140
This character indicates that when return pointer authentication is
being used, the function signs the return address using the B key.
Differential Revision: https://reviews.llvm.org/D93954
Add support for linking powerpcle code in LLD.
Rewrite lld/test/ELF/emulation-ppc.s to use a shared check block and add powerpcle tests.
Update tests.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D93917
D93491 implemented `--version` for the MachO LLD port, but asserts that the string contains something like "LLD N.N". However, this is just the cmake default for `LLD_VERSION_STRING`, and downstream users may choose a different value, e.g. a rolling distro may print "LLD trunk".
Every basic block section symbol created by -fbasic-block-sections will contain
".__part." to know that this symbol corresponds to a basic block fragment of
the function.
This patch solves two problems:
a) Like D89617, we want function symbols with suffixes to be properly qualified
so that external tools like profile aggregators know exactly what this
symbol corresponds to.
b) The current basic block naming just adds a ".N" to the symbol name where N is
some integer. This collides with how clang creates __cxx_global_var_init.N.
clang creates these symbol names to call constructor functions and basic
block symbol naming should not use the same style.
Fixed all the test cases and added an extra test for __cxx_global_var_init
breakage.
Differential Revision: https://reviews.llvm.org/D93082
We didn't have support for parsing DriverKit in our `-platform`
flag, so add that too. Also remove a bunch of unnecessary namespace
prefixes.
Reviewed By: #lld-macho, thakis
Differential Revision: https://reviews.llvm.org/D93741
It's an extension to ld64, but all the other ports have it, and
someone asked for it in PR43721.
While here, change the COFF help text to match the other ports.
Differential Revision: https://reviews.llvm.org/D93491
Before this, a hello world program would contain many many unnecessary
entries in its string table.
No behavior change, just makes the string table in the output smaller
and more like ld64's.
Differential Revision: https://reviews.llvm.org/D93711
Private extern symbols are used for things scoped to the linkage unit.
They cause duplicate symbol errors (so they're in the symbol table,
unlike TU-scoped truly local symbols), but they don't make it into the
export trie. They are created e.g. by compiling with
-fvisibility=hidden.
If two weak symbols have differing privateness, the combined symbol is
non-private external. (Example: inline functions and some TUs that
include the header defining it were built with
-fvisibility-inlines-hidden and some weren't).
A weak private external symbol implicitly has its "weak" dropped and
behaves like a regular strong private external symbol: Weak is an export
trie concept, and private symbols are not in the export trie.
If a weak and a strong symbol have different privateness, the strong
symbol wins.
If two common symbols have differing privateness, the larger symbol
wins. If they have the same size, the privateness of the symbol seen
later during the link wins (!) -- this is a bit lame, but it matches
ld64 and this behavior takes 2 lines less to implement than the less
surprising "result is non-private external), so match ld64.
(Example: `int a` in two .c files, both built with -fcommon,
one built with -fvisibility=hidden and one without.)
This also makes `__dyld_private` a true TU-local symbol, matching ld64.
To make this work, make the `const char*` StringRefZ ctor to correctly
set `size` (without this, writing the string table crashed when calling
getName() on the __dyld_private symbol).
Mention in CommonSymbol's comment that common symbols are now disabled
by default in clang.
Mention in -keep_private_externs's HelpText that the flag only has an
effect with `-r` (which we don't implement yet -- so this patch here
doesn't regress any behavior around -r + -keep_private_externs)). ld64
doesn't explicitly document it, but the commit text of
http://reviews.llvm.org/rL216146 does, and ld64's
OutputFile::buildSymbolTable() checks `_options.outputKind() ==
Options::kObjectFile` before calling `_options.keepPrivateExterns()`
(the only reference to that function).
Fixes PR48536.
Differential Revision: https://reviews.llvm.org/D93609
* Migrate most of our tests to use `split-file` instead of `echo`
* Remove individual `rm -f %t/libfoo.a` commands in favor of a top-level `rm -rf %t`
* Remove unused `Inputs/libfunction.s`
Reviewed By: #lld-macho, compnerd
Differential Revision: https://reviews.llvm.org/D93604
For x86-64, D33100 added a diagnostic for local-exec TLS relocations referencing a preemptible symbol.
This patch generalizes it to non-preemptible symbols (see `-Bsymbolic` in `tls.s`)
on all targets.
Local-exec TLS relocations resolve to offsets relative to a fixed point within
the static TLS block, which are only meaningful for the executable.
With this change, `clang -fpic -shared -fuse-ld=bfd a.c` on the following example will be flagged for AArch64/ARM/i386/x86-64/RISC-V
```
static __attribute__((tls_model("local-exec"))) __thread long TlsVar = 42;
long bump() { return ++TlsVar; }
```
Note, in GNU ld, at least arm, riscv and x86's ports have the similar
diagnostics, but aarch64 and ppc64 do not error.
Differential Revision: https://reviews.llvm.org/D93331
Alternative to D91611.
The TLS General Dynamic/Local Dynamic code sequences need to mark
`__tls_get_addr` with R_PPC64_TLSGD or R_PPC64_TLSLD, e.g.
```
addis r3, r2, x@got@tlsgd@ha # R_PPC64_GOT_TLSGD16_HA
addi r3, r3, x@got@tlsgd@l # R_PPC64_GOT_TLSGD16_LO
bl __tls_get_addr(x@tlsgd) # R_PPC64_TLSGD followed by R_PPC64_REL24
nop
```
However, there are two deviations form the above:
1. direct call to `__tls_get_addr`. This is essential to implement ld.so in glibc/musl/FreeBSD.
```
bl __tls_get_addr
nop
```
This is only used in a -shared link, and thus not subject to the GD/LD to IE/LE
relaxation issue below.
2. Missing R_PPC64_TLSGD/R_PPC64_TLSGD for compiler generated TLS references
According to Stefan Pintille, "In the early days of the transition from the
ELFv1 ABI that is used for big endian PowerPC Linux distributions to the ELFv2
ABI that is used for little endian PowerPC Linux distributions, there was some
ambiguity in the specification of the relocations for TLS. The GNU linker has
implemented support for correct handling of calls to __tls_get_addr with a
missing relocation. Unfortunately, we didn't notice that the IBM XL compiler
did not handle TLS according to the updated ABI until we tried linking XL
compiled libraries with LLD."
In short, LLD needs to work around the old IBM XL compiler issue.
Otherwise, if the object file is linked in -no-pie or -pie mode,
the result will be incorrect because the 4 instructions are partially
rewritten (the latter 2 are not changed).
Work around the compiler bug by disable General Dynamic/Local Dynamic to
Initial Exec/Local Exec relaxation. Note, we also disable Initial Exec
to Local Exec relaxation for implementation simplicity, though technically it can be kept.
ppc64-tls-missing-gdld.s demonstrates the updated behavior.
Reviewed By: #powerpc, stefanp, grimar
Differential Revision: https://reviews.llvm.org/D92959
Also remove iteration over ArchiveFile symbols in buildInputSectionPriorities --
that was rendered unnecessary after D92539, which included ObjFiles from
ArchiveFiles inside the `inputFiles` vector.
Reviewed By: #lld-macho, smeenai
Differential Revision: https://reviews.llvm.org/D93569
Obj-C symbols may have spaces and colons, which our previous order file
parser would be confused by. The order file format has made the very unfortunate
choice of using colons for its delimiters, which means that we have to use
heuristics to determine if a given colon is part of a symbol or not...
Reviewed By: #lld-macho, thakis
Differential Revision: https://reviews.llvm.org/D93567
The common encodings table holds only 127 entries. The encodings index for compact entries is 8 bits wide, and indexes 127..255 are stored locally to each second-level page. Prior to this diff, lld would `fatal()` if encodings overflowed the 127 limit.
This diff populates a per-second-level-page encodings table as needed. When the per-page encodings table hits its limit, we must terminate the page. If such early termination would consume fewer entries than a regular (non-compact) encoding page, then we prefer the regular format.
Caveat: one reason the common-encoding table might overflow is because of DWARF debug-info references, which are not yet implemented and will come with a later diff.
Differential Revision: https://reviews.llvm.org/D93267
We need to make sure not to emit R_X86_64_GOTPCRELX relocations for
instructions that use a REX prefix. If a REX prefix is present, we need to
instead use a R_X86_64_REX_GOTPCRELX relocation. The existing logic for
CALL64m, JMP64m, etc. already handles this by checking the HasREX parameter
and using it to determine which relocation type to use. Do this for all
instructions that can use relaxed relocations.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D93561
Currently, `ELFFile<ELFT>::getEntry` does not check an index of
an entry. Because of that the code might read past the end of the symbol
table silently. I've added a test to `llvm-readobj\ELF\relocations.test`
to demonstrate the possible issue. Also, I've added a unit test for
this method.
After this change, `getEntry` stops reporting the section index and
reuses the `getSectionContentsAsArray` method, which already has
all the validation needed. Our related warnings now provide
more and better context sometimes.
Differential revision: https://reviews.llvm.org/D93209
TREATMENT can be `error`, `warning`, `suppress`, or `dynamic_lookup`
The `dymanic_lookup` remains unimplemented for now.
Differential Revision: https://reviews.llvm.org/D93263
Fixes issue where if a line section doesn't start with a line number
then the addresses at the beginning of the section don't have line numbers.
For example, for a line section like this
```
0001:00000010-00000014, line/column/addr entries = 1
7 00000013 !
```
a line number wouldn't be found for addresses from 10 to 12.
This matches behavior when using the DIA SDK.
Differential Revision: https://reviews.llvm.org/D93306
As indicated by AArch64 ELF specification, symbols with st_other
marked with STO_AARCH64_VARIANT_PCS indicates it may follow a variant
procedure call standard with different register usage convention
(for instance SVE calls).
Static linkers must preserve the marking and propagate it to the dynamic
symbol table if any reference or definition of the symbol is marked with
STO_AARCH64_VARIANT_PCS, and add a DT_AARCH64_VARIANT_PCS dynamic tag if
there are R_<CLS>_JUMP_SLOT relocations that reference that symbols.
It implements https://bugs.llvm.org/show_bug.cgi?id=48368.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D93045
Note that dylibs without *any* refs will still be loaded in the usual
(strong) fashion.
Reviewed By: #lld-macho, thakis
Differential Revision: https://reviews.llvm.org/D93435
Weak references need not necessarily be satisfied at runtime (but they must
still be satisfied at link time). So symbol resolution still works as per usual,
but we now pass around a flag -- ultimately emitting it in the bind table -- to
indicate if a given dylib symbol is a weak reference.
ld64's behavior for symbols that have both weak and strong references is
a bit bizarre. For non-function symbols, it will emit a weak import. For
function symbols (those referenced by BRANCH relocs), it will emit a
regular import. I'm not sure what value there is in that behavior, and
since emulating it will make our implementation more complex, I've
decided to treat regular weakrefs like function symbol ones for now.
Fixes PR48511.
Reviewed By: #lld-macho, thakis
Differential Revision: https://reviews.llvm.org/D93369
Similar to D77853. Change ADRP to print the target address in hex, instead of the raw immediate.
The behavior is similar to GNU objdump but we also include `0x`.
Note: GNU objdump is not consistent whether or not to emit `0x` for different architectures. We try emitting 0x consistently for all targets.
```
GNU objdump: adrp x16, 10000000
Old llvm-objdump: adrp x16, #0
New llvm-objdump: adrp x16, 0x10000000
```
`adrp Xd, 0x...` assembles to a relocation referencing `*ABS*+0x10000` which is not intended. We need to use a linker or use yaml2obj.
The main test is `test/tools/llvm-objdump/ELF/AArch64/pcrel-address.yaml`
Differential Revision: https://reviews.llvm.org/D93241
Fix PR48357: If .rela.dyn appears as an output section description, its type may
be SHT_RELA (due to the empty synthetic .rela.plt) while there is no input
section. The empty .rela.dyn may be retained due to a reference in a linker
script. Don't crash.
Reviewed By: grimar
Differential Revision: https://reviews.llvm.org/D93367
From what I can tell, it's essentially identical to
`-sub_library`, but it doesn't match files ending in ".dylib".
Reviewed By: #lld-macho, thakis
Differential Revision: https://reviews.llvm.org/D93276
Their addresses are already encoded as section-relative offsets, so
there's no need to rebase them at runtime. {D85080} has some context
on the weirdness of TLV sections.
Fixes llvm.org/PR48491.
Reviewed By: #lld-macho, thakis
Differential Revision: https://reviews.llvm.org/D93257
We were not setting forceWeakImport for file paths given by
`-weak_library` if we had already loaded the file. This diff fixes that
by having `loadDylib` return a cached DylibFile instance even if we have
already loaded that file.
We still avoid emitting multiple LC_LOAD_DYLIBs, but we achieve this by
making inputFiles a SetVector instead of relying on the `loadedDylibs`
cache.
Reviewed By: #lld-macho, smeenai
Differential Revision: https://reviews.llvm.org/D93255
