For a DSO with all DT_NEEDED entries accounted for, if it contains an
undefined non-weak symbol that shares a name with a non-exported
definition (hidden visibility or localized by a version script), and
there is no DSO definition, we should report an error.
#70769 implemented the error when we see `ref.so def-hidden.so`. This patch
implementes the error when we see `def-hidden.so ref.so`, matching GNU
ld.
Close#86777
`TargetEndianness` is long and unwieldy. "Target" in the name is confusing. Rename it to "Endianness".
I cannot find noticeable out-of-tree users of `TargetEndianness`, but
keep `TargetEndianness` to make this patch safer. `TargetEndianness`
will be removed by a subsequent change.
Fixes: 36146d2b6b
When `doParseFile template defintion` in InputFiles.cpp is optimized
out, we will get a link failure. Actually, we can move the file parsing
loop from Driver.too to InputFiles.cpp and merge it with
parseArmCMSEImportLib.
Unknown section sections may require special linking rules, and
rejecting such sections for older linkers may be desired. For example,
if we introduce a new section type to replace a control structure (e.g.
relocations), it would be nice for older linkers to reject the new
section type. GNU ld allows certain unknown section types:
* [SHT_LOUSER,SHT_HIUSER] and non-SHF_ALLOC
* [SHT_LOOS,SHT_HIOS] and non-SHF_OS_NONCONFORMING
but reports errors and stops linking for others (unless
--no-warn-mismatch is specified). Port its behavior. For convenience, we
additionally allow all [SHT_LOPROC,SHT_HIPROC] types so that we don't
have to hard code all known types for each processor.
Close https://github.com/llvm/llvm-project/issues/84812
This patch adds full support for linking SystemZ (ELF s390x) object
files. Support should be generally complete:
- All relocation types are supported.
- Full shared library support (DYNAMIC, GOT, PLT, ifunc).
- Relaxation of TLS and GOT relocations where appropriate.
- Platform-specific test cases.
In addition to new platform code and the obvious changes, there were a
few additional changes to common code:
- Add three new RelExpr members (R_GOTPLT_OFF, R_GOTPLT_PC, and
R_PLT_GOTREL) needed to support certain s390x relocations. I chose not
to use a platform-specific name since nothing in the definition of these
relocs is actually platform-specific; it is well possible that other
platforms will need the same.
- A couple of tweaks to TLS relocation handling, as the particular
semantics of the s390x versions differ slightly. See comments in the
code.
This was tested by building and testing >1500 Fedora packages, with only
a handful of failures; as these also have issues when building with LLD
on other architectures, they seem unrelated.
Co-authored-by: Tulio Magno Quites Machado Filho <tuliom@redhat.com>
The interaction between --warn-backrefs was not tested, but if
--defsym-created reference causes archive member extraction, it seems
reasonable to suppress the diagnostic, which was the behavior before #78944.
Commit 1981b1b6b9 unexpectedly strengthened
--no-allow-shlib-undefined to catch a kind of ODR violation.
More precisely, when all three conditions are met, the new
`--no-allow-shlib-undefined` code reports an error.
* There is a DSO undef that has been satisfied by a definition from
another DSO.
* The `SharedSymbol` is overridden by a non-exported (usually of hidden
visibility) definition in a relocatable object file (`Defined`).
* The section containing the `Defined` is garbage-collected (it is not
part of `.dynsym` and is not marked as live).
Technically, the hidden Defined in the executable can be intentional: it
can be meant to remain non-exported and not interact with any dynamic
symbols of the same name that might exist in other DSOs. To allow for
such use cases, allocate a new bit in
Symbol and relax the --no-allow-shlib-undefined check to before
commit 1981b1b6b9.
Based on https://reviews.llvm.org/D45375 . Introduce a new InputFile
kind `InternalKind`, use it for
* `ctx.internalFile`: for linker-defined symbols and some synthesized
`Undefined`
* `createInternalFile`: for symbol assignments and --defsym
I picked "internal" instead of "synthetic" to avoid confusion with
SyntheticSection.
Currently a symbol's file is one of: nullptr, ObjKind, SharedKind,
BitcodeKind, BinaryKind. Now it's non-null (I plan to add an
`assert(file)` to Symbol::Symbol and change `toString(const InputFile
*)`
separately).
Debugging and error reporting gets improved. The immediate user-facing
difference is more descriptive "File" column in the --cref output. This
patch may unlock further simplification.
Currently each symbol assignment gets its own
`createInternalFile(cmd->location)`. Two symbol assignments in a linker
script do not share the same file. Making the file the same would be
nice, but would require non trivial code.
LazySymbol (used by wasm port) is a more accurate name (the struct is
not about an object). However, the ELF port calls this LazyObject likely
because we used to have LazyArchive (removed by
https://reviews.llvm.org/D119074), and LazyObject has a similar naming
convention (LazyObjectSymbol would be better, but it is too long).
Reviewers: dschuff
Pull Request: https://github.com/llvm/llvm-project/pull/78809
The two fields are similar.
`versionId` is the Verdef index in the output file. It is set for
`--exclude-id=`, version script patterns, and `sym@ver` symbols.
`verdefIndex` is the Verdef index of a Sharedfile (SharedSymbol or a
copy-relocated Defined), the default value -1 is also used to indicate
that the symbol has not been matched by a version script pattern
(https://reviews.llvm.org/D65716).
It seems confusing to have two fields. Merge them so that we can
allocate one bit for #70130 (suppress --no-allow-shlib-undefined
error in the presence of a DSO definition).
The two fields are similar.
`versionId` is the Verdef index in the output file. It is set for
version script patterns and `sym@ver` symbols.
`verdefIndex` is the Verdef index of a SharedSymbol. The default value
-1 is also used to indicate that the symbol has not been matched by a
version script pattern (https://reviews.llvm.org/D65716).
It seems confusing to have two fields. Merge them so that we can
allocate one bit for #70130 (suppress --no-allow-shlib-undefined
error in the presence of a DSO definition).
Note that llvm::support::endianness has been renamed to
llvm::endianness while becoming an enum class as opposed to an
enum. This patch replaces support::{big,little,native} with
llvm::endianness::{big,little,native}.
Integrating MTE globals on Android revealed a lot of cases where
libraries are built as both archives and DSOs, and they're linked into
fully static and dynamic executables respectively.
MTE globals doesn't work for fully static executables. They need a
dynamic loader to process the special R_AARCH64_RELATIVE relocation
semantics with the encoded offset. Fully static executables that had
out-of-bounds derived symbols (like 'int* foo_end = foo[16]') crash
under MTE globals w/ static executables. So, LLD in its current form
simply errors out when you try and compile a fully static executable
that has a single MTE global variable in it.
It seems like a much better idea to simply have LLD not do the special
work for MTE globals in fully static contexts, and to drop any
unnecessary metadata. This means that you can build archives with MTE
globals and link them into both fully-static and dynamic executables.
Before this patch, with MSVC I was seeing:
```
[304/334] Building CXX object tools\lld\ELF\CMakeFiles\lldELF.dir\InputFiles.cpp.obj
C:\git\llvm-project\lld\ELF\InputFiles.h(327): warning C4661: 'void lld::elf::ObjFile<llvm::object::ELF32LE>::importCmseSymbols(void)': no suitable definition provided for explicit template instantiation request
C:\git\llvm-project\lld\ELF\InputFiles.h(291): note: see declaration of 'lld::elf::ObjFile<llvm::object::ELF32LE>::importCmseSymbols'
C:\git\llvm-project\lld\ELF\InputFiles.h(327): warning C4661: 'void lld::elf::ObjFile<llvm::object::ELF32LE>::redirectCmseSymbols(void)': no suitable definition provided for explicit template instantiation request
C:\git\llvm-project\lld\ELF\InputFiles.h(292): note: see declaration of 'lld::elf::ObjFile<llvm::object::ELF32LE>::redirectCmseSymbols'
```
This patch removes `redirectCmseSymbols` which is not defined. And it
imports `importCmseSymbols` in InputFiles.cpp, because it is already
explicitly instantiated in ARM.cpp.
This adds support for the LoongArch ELF psABI v2.00 [1] relocation
model to LLD. The deprecated stack-machine-based psABI v1 relocs are not
supported.
The code is tested by successfully bootstrapping a Gentoo/LoongArch
stage3, complete with common GNU userland tools and both the LLVM and
GNU toolchains (GNU toolchain is present only for building glibc,
LLVM+Clang+LLD are used for the rest). Large programs like QEMU are
tested to work as well.
[1]: https://loongson.github.io/LoongArch-Documentation/LoongArch-ELF-ABI-EN.html
Reviewed By: MaskRay, SixWeining
Differential Revision: https://reviews.llvm.org/D138135
This commit provides linker support for Cortex-M Security Extensions (CMSE).
The specification for this feature can be found in ARM v8-M Security Extensions:
Requirements on Development Tools.
The linker synthesizes a security gateway veneer in a special section;
`.gnu.sgstubs`, when it finds non-local symbols `__acle_se_<entry>` and `<entry>`,
defined relative to the same text section and having the same address. The
address of `<entry>` is retargeted to the starting address of the
linker-synthesized security gateway veneer in section `.gnu.sgstubs`.
In summary, the linker translates input:
```
.text
entry:
__acle_se_entry:
[entry_code]
```
into:
```
.section .gnu.sgstubs
entry:
SG
B.W __acle_se_entry
.text
__acle_se_entry:
[entry_code]
```
If addresses of `__acle_se_<entry>` and `<entry>` are not equal, the linker
considers that `<entry>` already defines a secure gateway veneer so does not
synthesize one.
If `--out-implib=<out.lib>` is specified, the linker writes the list of secure
gateway veneers into a CMSE import library `<out.lib>`. The CMSE import library
will have 3 sections: `.symtab`, `.strtab`, `.shstrtab`. For every secure gateway
veneer <entry> at address `<addr>`, `.symtab` contains a `SHN_ABS` symbol `<entry>` with
value `<addr>`.
If `--in-implib=<in.lib>` is specified, the linker reads the existing CMSE import
library `<in.lib>` and preserves the entry function addresses in the resulting
executable and new import library.
Reviewed By: MaskRay, peter.smith
Differential Revision: https://reviews.llvm.org/D139092
This reverts commit c4fea39056.
I am reverting this for now until I figure out how to fix
the build bot errors and warnings.
Errors:
llvm-project/lld/ELF/Arch/ARM.cpp:1300:29: error: expected primary-expression before ‘>’ token
osec->writeHeaderTo<ELFT>(++sHdrs);
Warnings:
llvm-project/lld/ELF/Arch/ARM.cpp:1306:31: warning: left operand of comma operator has no effect [-Wunused-value]
This commit provides linker support for Cortex-M Security Extensions (CMSE).
The specification for this feature can be found in ARM v8-M Security Extensions:
Requirements on Development Tools.
The linker synthesizes a security gateway veneer in a special section;
`.gnu.sgstubs`, when it finds non-local symbols `__acle_se_<entry>` and `<entry>`,
defined relative to the same text section and having the same address. The
address of `<entry>` is retargeted to the starting address of the
linker-synthesized security gateway veneer in section `.gnu.sgstubs`.
In summary, the linker translates input:
```
.text
entry:
__acle_se_entry:
[entry_code]
```
into:
```
.section .gnu.sgstubs
entry:
SG
B.W __acle_se_entry
.text
__acle_se_entry:
[entry_code]
```
If addresses of `__acle_se_<entry>` and `<entry>` are not equal, the linker
considers that `<entry>` already defines a secure gateway veneer so does not
synthesize one.
If `--out-implib=<out.lib>` is specified, the linker writes the list of secure
gateway veneers into a CMSE import library `<out.lib>`. The CMSE import library
will have 3 sections: `.symtab`, `.strtab`, `.shstrtab`. For every secure gateway
veneer <entry> at address `<addr>`, `.symtab` contains a `SHN_ABS` symbol `<entry>` with
value `<addr>`.
If `--in-implib=<in.lib>` is specified, the linker reads the existing CMSE import
library `<in.lib>` and preserves the entry function addresses in the resulting
executable and new import library.
Reviewed By: MaskRay, peter.smith
Differential Revision: https://reviews.llvm.org/D139092
The generic ABI says:
> Padding is present, if necessary, to ensure 8 or 4-byte alignment for the next note entry (depending on whether the file is a 64-bit or 32-bit object). Such padding is not included in descsz.
Our parsing code currently aligns n_namesz. Fix the bug by aligning the start
offset of the descriptor instead. This issue has been benign because the primary
uses of sh_addralign=8 notes are `.note.gnu.property`, where
`sizeof(Elf_Nhdr) + sizeof("GNU") = 16` (already aligned by 8).
In practice, many 64-bit systems incorrectly use sh_addralign=4 notes.
We can use sh_addralign (= p_align) to decide the descriptor padding.
Treat an alignment of 0 and 1 as 4. This approach matches modern GNU readelf
(since 2018).
We have a few tests incorrectly using sh_addralign=0. We may make our behavior
stricter after fixing these tests.
Linux kernel dumped core files use `p_align=0` notes, so we need to support the
case for compatibility.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D150022
--remap-inputs-file= can be specified multiple times, each naming a
remap file that contains `from-glob=to-file` lines or `#`-led comments.
('=' is used a separator a la -fdebug-prefix-map=)
--remap-inputs-file= can be used to:
* replace an input file. E.g. `"*/libz.so=exp/libz.so"` can replace a resolved
`-lz` without updating the input file list or (if used) a response file.
When debugging an application where a bug is isolated to one single
input file, this option gives a convenient way to test fixes.
* remove an input file with `/dev/null` (changed to `NUL` on Windows), e.g.
`"a.o=/dev/null"`. A build system may add unneeded dependencies.
This option gives a convenient way to test the result removing some inputs.
`--remap-inputs=a.o=aa.o` can be specified to provide one pattern without using
an extra file.
(bash/zsh process substitution is handy for specifying a pattern without using
a remap file, e.g. `--remap-inputs-file=<(printf 'a.o=aa.o')`, but it may be
unavailable in some systems. An extra file can be inconvenient for a build
system.)
Exact patterns are tested before wildcard patterns. In case of a tie, the first
patterns wins. This is an implementation detail that users should not rely on.
Co-authored-by: Marco Elver <elver@google.com>
Link: https://discourse.llvm.org/t/rfc-support-exclude-inputs/70070
Reviewed By: melver, peter.smith
Differential Revision: https://reviews.llvm.org/D148859
By using emplace_back, as well as converting some loops to for-each, we can do more efficient vectorization.
Make copy constructor for TemporaryFile noexcept.
Reviewed By: #lld-macho, int3
Differential Revision: https://reviews.llvm.org/D139552
Adds support for the following flags:
* --thinlto-index-only, --thinlto-index-only=
* --thinlto-emit-imports-files
* --thinlto-emit-index-files
* --thinlto-object-suffix-replace=
* --thinlto-prefix-replace=
See https://blog.llvm.org/2016/06/thinlto-scalable-and-incremental-lto.html
for some words on --thinlto-index-only.
I don't really need the other flags, but they were in the vicinity
and _someone_ might need them, so I figured I'd add them too.
`-object_path_lto` now sets `c.AlwaysEmitRegularLTOObj` as in the other ports,
which means it can now only point to a filename for non-thin LTO.
I think that was the intent of D129705 anyways, so update
test/MachO/lto-object-path.ll to use a non-thin bitcode file for that test.
Differential Revision: https://reviews.llvm.org/D138451
Currently we take the first SHT_RISCV_ATTRIBUTES (.riscv.attributes) as the
output. If we link an object without an extension with an object with the
extension, the output Tag_RISCV_arch may not contain the extension and some
tools like objdump -d will not decode the related instructions.
This patch implements
Tag_RISCV_stack_align/Tag_RISCV_arch/Tag_RISCV_unaligned_access merge as
specified by
https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-elf.adoc#attributes
For the deprecated Tag_RISCV_priv_spec{,_minor,_revision}, dump the attribute to
the output iff all input agree on the value. This is different from GNU ld but
our simple approach should be ok for deprecated tags.
`RISCVAttributeParser::handler` currently warns about unknown tags. This
behavior is retained. In GNU ld arm, tags >= 64 (mod 128) are ignored with a
warning. If RISC-V ever wants to do something similar
(https://github.com/riscv-non-isa/riscv-elf-psabi-doc/issues/352), consider
documenting it in the psABI and changing RISCVAttributeParser.
Like GNU ld, zero value integer attributes and empty string attributes are not
dumped to the output.
Reviewed By: asb, kito-cheng
Differential Revision: https://reviews.llvm.org/D138550
```
template <typename T> struct A {
A() {}
int value = 0;
};
template <typename Value> struct B {
static A<int> a;
};
template <typename Value> A<int> B<Value>::a;
inline int foo() {
return B<int>::a.value;
}
```
```
clang++ -c -fno-pic a.cc -o weak.o
g++ -c -fno-pic a.cc -o unique.o # --enable-gnu-unique-object
# Duplicate symbol error. In postParse, we do not check `sym.binding`
ld.lld -e 0 weak.o unique.o
```
Mixing GCC and Clang object files in this case is not ideal. .bss._ZGVN1BIiE1aE
has different COMDAT groups. It appears to work in practice because the guard
variable prevents harm due to double initialization.
For the linker, we just stick with the rule that a weak binding does not cause
"duplicate symbol" errors.
Close https://github.com/llvm/llvm-project/issues/58232
Differential Revision: https://reviews.llvm.org/D136381
