--export-dynamic should be a no-op when ctx.hasDynsym is false.
* Drop unneeded ctx.hasDynsym checks.
* Static linking with --export-dynamic does not prevent devirtualization.
Reland 994cea3f0a2d0caf4d66321ad5a06ab330144d89 after bolt tests no
longer rely on -pie --unresolved-symbols=ignore-all with no input DSO
generating PLT entries.
---
Commit f10441ad003236ef3b9e5415a571d2be0c0ce5ce , while dropping a
special case for isUndefWeak and --no-dynamic-linking, made
--export-dynamic ineffective when -pie is used without any input DSO.
This change restores --export-dynamic and unifies -pie and -pie
--no-dynamic-linker when there is no input DSO.
* -pie with no input DSO suppresses undefined symbols in .dynsym.
Previously this only appied to -pie --no-dynamic-linker.
* As a side effect, -pie with no input DSO suppresses PLT.
Commit f10441ad003236ef3b9e5415a571d2be0c0ce5ce dropped a special case
for isUndefWeak and --no-dynamic-linking but also made --export-dynamic
ineffective for static PIE.
This change restores the --export-dynamic behavior and entirely drops
special handling of --no-dynamic-linker:
* -pie with no input DSO, similar to --no-dynamic-linker, suppresses
undefined symbols in .dynsym
The new behaviors resemble GNU ld more.
Commit 3733ed6f1c6b0eef1e13e175ac81ad309fc0b080 introduced isExported to
cache includeInDynsym. If we don't unnecessarily set isExported for
undefined symbols, exportDynamic/includeInDynsym can be replaced with
isExported.
`includeInDynsym` has a special case for isUndefWeak and
--no-dynamic-linker, which can be removed if we simplify disallow
dynamic symbols for static-pie.
The partition feature reports errors only when a symbol `isExported`.
We need to link in a DSO to trigger the mips error.
isExported, intended to replace exportDynamic, is primarily set in two
locations, (a) after parseSymbolVersion and (b) during demoteSymbols.
In the future, we should try removing exportDynamic. Currently,
merging exportDynamic/isExported would cause
riscv-gp.s to fail:
* The first isExported computation considers the undefined symbol exported
* Defined as a linker-synthesized symbol
* isExported remains true, while it should be false
When computing whether a defined symbol is exported, we set
`exportDynamic` in Defined and CommonSymbol's ctor and merge the bit in
symbol resolution. The complexity is for the LTO special case
canBeOmittedFromSymbolTable, which can be simplified by introducing a
new bit.
We might simplify the state by caching includeInDynsym in exportDynamic
in the future.
so that we can remove the global `ctx` from toString implementations.
Rename lld::toString (to lld:🧝:toStr) to simplify name lookup (we
have many llvm::toString and another lld::toString(const llvm::opt::Arg
&)).
Ctx was introduced in March 2022 as a more suitable place for such
singletons.
llvm/Support/thread.h includes <thread>, which transitively includes
sstream in libc++ and uses ios_base::in, so we cannot use `#define in ctx.sec`.
`symtab, config, ctx` are now the only variables using
LLVM_LIBRARY_VISIBILITY.
so that --noinhibit-exec downgrades the error to a warning, which helps
debugging when `PHDRS` is specified without `PT_TLS`. Also update the
message to make it accurate: STT_TLS may exist in the absence of PT_TLS.
In addition, invoking `exitLld(1)` (through `fatal`) is problematic
(#66974): When a thread is `exitLld(1)`, triggering `llvm_shutdown`,
another thread may be at `relocateAlloc`, accessing `sec.relocs()` which
got destroyed(tampered?), leading to
incorrect `llvm_unreachable("invalid expression")`.
Ctx was introduced in March 2022 as a more suitable place for such
singletons. ctx's hidden visibility optimizes generated instructions.
This change fixes a pitfall: certain ElfSym members (e.g.
globalOffsetTable, tlsModuleBase) were not zeroed and might be stale
when lld:🧝:link was invoked the second time.
Ctx was introduced in March 2022 as a more suitable place for such
singletons. ctx's hidden visibility optimizes generated instructions.
bufferStart and tlsPhdr, which are not OutputSection, can now be moved
outside of `Out`.
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).
When an input section is matched by /DISCARD/ in a linker script, GNU ld
reports errors for relocations referencing symbols defined in the section:
`.aaa' referenced in section `.bbb' of a.o: defined in discarded section `.aaa' of a.o
Implement the error by demoting eligible symbols to `Undefined` and changing
STB_WEAK to STB_GLOBAL. As a side benefit, in relocatable links, relocations
referencing symbols defined relative to /DISCARD/ discarded sections no longer
set symbol/type to zeros.
It's arguable whether a weak reference to a discarded symbol should lead to
errors. GNU ld reports an error and our demoting approach reports an error as
well.
Close#58891
Co-authored-by: Bevin Hansson <bevin.hansson@ericsson.com>
This adds a new -Bsymbolic option that directly binds all non-weak
symbols. There's a couple of reasons motivating this:
* The new flag will match the default behavior on Mach-O, so you can get
consistent behavior across platforms.
* We have use cases for which making weak data preemptible is useful,
but we don't want to pessimize access to non-weak data. (For a large
internal app, we measured 2000+ data symbols whose accesses would be
unnecessarily pessimized by `-Bsymbolic-functions`.)
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D158322
As suggested by @erichkeane in
https://reviews.llvm.org/D141451#inline-1429549
There's potential for a lot more cleanups around these APIs. This is
just a start.
Callers need to be more careful about sub-expressions producing strings
that don't outlast the expression using `llvm::demangle`. Add a
release note.
Differential Revision: https://reviews.llvm.org/D149104
This reverts commit c117c2c8ba4afd45a006043ec6dd858652b2ffcc.
itaniumDemangle calls std::strlen with the results of
std::string_view::data() which may not be NUL-terminated. This causes
lld/test/wasm/why-extract.s to fail when "expensive checks" are enabled
via -DLLVM_ENABLE_EXPENSIVE_CHECKS=ON. See D149675 for further
discussion. Back this out until the individual demanglers are converted
to use std::string_view.
As suggested by @erichkeane in
https://reviews.llvm.org/D141451#inline-1429549
There's potential for a lot more cleanups around these APIs. This is
just a start.
Callers need to be more careful about sub-expressions producing strings
that don't outlast the expression using ``llvm::demangle``. Add a
release note.
Reviewed By: MaskRay, #lld-macho
Differential Revision: https://reviews.llvm.org/D149104
This implements support for relaxing these relocations to use the GP
register to compute addresses of globals in the .sdata and .sbss
sections.
This feature is off by default and must be enabled by passing
--relax-gp to the linker.
The GP register might not always be the "global pointer". It can
be used for other purposes. See discussion here
https://github.com/riscv-non-isa/riscv-elf-psabi-doc/pull/371
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D143673
