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
{D116279}, in addition to adding support for other demanglers, also
factored out some of the demangling logic. However, I don't think the
abstraction really carries its weight -- after {D135942}, only the ELF
and WASM backends call it with anything other than a non-constant
`shouldDemangle` argument. The COFF and Mach-O backends were already
doing the should-demangle check before calling `demangle()`.
Reviewed By: MaskRay, #lld-macho
Differential Revision: https://reviews.llvm.org/D135943
Add LLVM_LIBRARY_VISIBILITY to remove unneeded GOT and unique_ptr
indirection. We can move other global variables into ctx without
indirection concern. In the long term we may consider passing Ctx
as a parameter to various functions and eliminate global state as
much as possible and then remove `Ctx::reset`.
Symbol::replace intends to overwrite a few fields (mostly Elf{32,64}_Sym
fields), but the implementation copies all fields then restores some old fields.
This is error-prone and wasteful. Add Symbol::overwrite to copy just the
needed fields and add other overwrite member functions to copy the extra
fields.
