The rule here, which I'm copying from the ELF linker, is that shared
library symbols should take presence, unless the symbol has already be
extracted from the archive. e.g:
```
$ wasm-ld foo.a foo.so ref.o // .so wins
$ wasm-ld foo.a ref.o foo.so // .a wins
```
In the first case the shared library takes precedence because the lazy
symbol is replaced by the .so symbol before it is extracted from the
archive. In the second example the ref.o file causes the archive to be
exracted before the .so file is processed, so in that case the archive
file wins.
Fixes: https://github.com/emscripten-core/emscripten/issues/23501
For each imported module, emit null-terminated native import entries,
followed by null-terminated EC entries. If a view lacks imports for a
given module, only terminators are emitted. Use ARM64X relocations to
skip native entries in the EC view.
Move `delayLoadHelper` and `tailMergeUnwindInfoChunk` to `SymbolTable`
since they are different for each symbol table.
This change prepares for ARM64X delay-load imports support (#124600).
Delaying the `setLocation` call is problematic on ARM64X because the
order of addresses may not align with the order of symbols.
Commit 2a26292388fcab0c857c91b2d08074c33abd37e8 made `isExported`
accurate except a few linker-synthesized symbols in finalizeSections.
We can collect these linker-synthesized symbols into a vector
and avoid recomputation for other symbols.
This is reland of 1a4d6de1b532149b10522eae5dabce39e5f7c687 after
`isExported` has been made accurate by f10441ad003236ef3b9e5415a571d2be0c0ce5ce
The reverted
1a4d6de1b532149b10522eae5dabce39e5f7c687
("[ELF] Remove redundant isExported computation")
had incorrect
```
+ if (sym->includeInDynsym(ctx))
+ sym->isExported = true;
```
causing undefined weak symbols (defined in archives, demoted; e.g.
__cxa_finalize) to be exported for static-pie.
Add a regression test for this corner case. The issue actually exposed
another issue related to includeInDynsym, which has been fixed by
f10441ad003236ef3b9e5415a571d2be0c0ce5ce.
`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.
This mode does not retain definitions in GNU ld. While we do, it's not
consistent with the decision that there is no .dynsym . We will change
this and simplify some internal representations.
PR #117514 refactored BPSectionOrderer to be used by the ELF port
but introduced some inefficiency:
* BPSectionBase/BPSymbol are wrappers around a single pointer.
The numbers of sections and symbols could be huge, and the extra
allocations are memory inefficient.
* Reconstructing the returned DenseMap (since BPSectionBase != InputSectin)
is wasteful.
This patch refactors BPSectionOrderer with Curiously Recurring Template
Pattern and eliminates the inefficiency. In addition,
`symbolToSectionIdxs` is removed and `rootSymbolToSectionIdxs` building
is moved to lld/MachO: while getting sections for symbols is cheap in
Mach-O, it is awkward and inefficient in the ELF port.
While here, add a file-level comment and replace some `StringMap<*>`
(which copies strings) with `DenseMap<CachedHashStringRef, *>`.
Pull Request: https://github.com/llvm/llvm-project/pull/124482
Note that PointerUnion::dyn_cast has been soft deprecated in
PointerUnion.h:
// FIXME: Replace the uses of is(), get() and dyn_cast() with
// isa<T>, cast<T> and the llvm::dyn_cast<T>
This patch migrates uses of PointerUnion::dyn_cast to
dyn_cast_if_present (see the definition of PointerUnion::dyn_cast).
Note that we cannot use dyn_cast in any of the migrations in this
patch; placing
assert(!X.isNull());
just before any of dyn_cast_if_present in this patch triggers some
failure in check-lld.
This enables the LLD_IN_TEST=2 testing mode for
```
path/to/llvm-lit -sv --param RUN_LLD_MAIN_TWICE=1 lld/test/ELF
```
When `Fatal` is called, `RunSafely` will return false.
For the first invocation in LLD_IN_TEST=2 mode, `inTestOutputDisabled`
is true and lld will not write to stdout/stderr, making many tests fail.
(This essentially discourages `Fatal` calls in the source code.)
Add XFAIL: main-run-twice to these tests similar to
https://reviews.llvm.org/D112898 for Mach-O
```
comment="This test intentionally checks for fatal errors, and fatal errors aren't supported for testing when main is run twice."
xargs </tmp/0 sed -Ei "1s/(;|#|\/\/) REQUIRES: .*/\0\n\1 "$comment"\n\1 XFAIL: main-run-twice/;t;1s/^/# "$comment"\n# XFAIL: main-run-twice\n/"
```
This reverts commit 048f35037779763963c4b4478a0884e828ea9538.
This reverts commit f7bbc40b0736cc417f57cd039b098b504cf6a71f.
Related to #95949. A developer with no prior lld contribution and very
little AMD contribution sneaked in these application-specific section
order rules we discourage.
Commit 2a26292388fcab0c857c91b2d08074c33abd37e8 made `isExported`
accurate except a few linker-synthesized symbols in finalizeSections.
We can collect these linker-synthesized symbols into a vector
and avoid recomputation for other symbols.
LTO compilation might define symbols not in the symbol table (e.g.
__emutls_v.x in test/ELF/lto/wrap-unreferenced-before-codegen.test).
These symbols have a false `isExported` until
`demoteSymbolsAndComputeIsPreemptible`. This is usually benign as we do
not reference `isExported` that early.
Ensure that `isExported` is correct early. This helps remove a redundant
`isExported` computation in `demoteSymbolsAndComputeIsPreemptible`.
In hybrid images, the PE header references a single IAT for both native
and EC views, merging entries where possible. When merging isn't
feasible, different imports are grouped together, and ARM64X relocations
are emitted as needed.
In LLD_IN_TEST=2 mode, when a thread calls Fatal, there will be no
output even if the process exits with code 1. Change the Fatal to
ErrAlways (not-recoverable) as subsequent code assumes SHF_LINK_ORDER
sh_link is correct.
In LLD_IN_TEST=2 mode, when a thread calls Fatal, there will be no
output even if the process exits with code 1. Change a few Fatal to
recoverable Err.
In LLD_IN_TEST=2 mode, when a thread calls Fatal, there will be no
output even if the process exits with code 1. Change a few Fatal to
recoverable Err.
In LLD_IN_TEST=2 mode, when a thread calls Fatal, there will be no
output even if the process exits with code 1. Change a few Fatal to
recoverable Err.
These diagnostics are mostly reported by a thread during writeSections.
In LLD_IN_TEST=2 mode, when a thread calls Fatal, there will be no
output even if the process exits with code 1.
`NullChunk` instances do write data, even if it's always zero. Setting
`hasData` to false causes `Writer::assignAddresses` to ignore them
when calculating `rawSize`. This typically isn't an issue, as null chunks
are usually positioned within a section, and later chunks adjust the
size accordingly.
However, on ARM64EC, the auxiliary IAT is placed at the end of the
`.rdata` section and terminates with a null chunk. As a result, `rawSize`
is never updated to account for it, and space for the null chunk is not
allocated. Consequently, when `NullChunk::writeTo` is called, it receives
an invalid pointer - either pointing to the next section or beyond the
allocated buffer.
This is a follow-up to #120452 in a way.
Since lld/COFF does not yet insert all defined in an obj file before all
undefineds (ELF and MachO do this, see #67445 and things linked from
there), it's possible that:
1. We add an obj file a.obj
2. a.obj contains an undefined that's in b.obj, causing b.obj to be
added
3. b.obj contains an undefined that's in a part of a.obj that's not yet
in the symbol table, causing a recursive load of a.obj, which adds the
symbols in there twice, leading to duplicate symbol errors.
For normal archives, `ArchiveFile::addMember()` has a `seen` check to
prevent this. For start-lib lazy objects, we can just check if the
archive is still lazy at the recursive call.
This bug is similar to issue #59162.
(Eventually, we'll probably want to do what the MachO and ELF ports do.)
Includes a test that caused duplicate symbol diagnostics before this
code change.
The symbol string table does not have deduplication.
Here we add code to deduplicate the symbol string table.
This has a rather large size impact (20-30%) on unstripped binaries
(typically debug binaries) but no size impact on stripped
binaries(typically release binaries).
We enable deduplication by default and add a flag to disable it
(`-no-deduplicate-symbol-strings`).
.note.GNU-stack with the SHF_EXECINSTR flag requires an executable
stack. This is exceedingly rare. We report an error to force
the user to explicitly request an executable stack.
Close#121234
Pull Request: https://github.com/llvm/llvm-project/pull/124068
ecb5ea6a266d5cc4e05252f6db4c73613b73cc3b tried to fix cases when LLD
links what seems to be import library header objects from MSVC. However,
the fix seems incorrect; the review at https://reviews.llvm.org/D133627
concluded that if this (treating this kind of symbol as a common symbol)
is what link.exe does, it's fine.
However, this is most probably not what link.exe does. The symbol
mentioned in the commit message of
ecb5ea6a266d5cc4e05252f6db4c73613b73cc3b would be a common symbol with a
size of around 3 GB; this is not what might have been intended.
That commit tried to avoid running into the error ".idata$4 should not
refer to special section 0"; that issue is fixed for a similar style of
section symbols in 4a4a8a1476b1386b523dc5b292ba9a5a6748a9cf.
Therefore, revert ecb5ea6a266d5cc4e05252f6db4c73613b73cc3b and extend
the fix from 4a4a8a1476b1386b523dc5b292ba9a5a6748a9cf to also work for
the section symbols in MSVC generated import libraries.
The main detail about them, is that for symbols of type
IMAGE_SYM_CLASS_SECTION, the Value field is not an offset, but it is an
optional set of flags, corresponding to the Characteristics of the
section header (although it may be empty).
This is a reland of a previous version of this commit, earlier merged in
9457418e66766d8fafc81f85eb8045986220ca3e / #122811. The previous version
failed tests when run with address sanitizer. The issue was that the
synthesized coff_symbol_generic object actually will be used to access a
full coff_symbol16 or coff_symbol32 struct, see
DefinedCOFF::getCOFFSymbol. Therefore, we need to make a copy of the
full size of either of them.
Depends on #120010
Support `R_AARCH64_AUTH_TLSDESC_ADR_PAGE21`, `R_AARCH64_AUTH_TLSDESC_LD64_LO12`
and `R_AARCH64_AUTH_TLSDESC_LD64_LO12` static relocations and
`R_AARCH64_AUTH_TLSDESC` dynamic relocation. IE/LE optimization is not
currently supported for AUTH TLSDESC.
Note that PointerUnion::dyn_cast has been soft deprecated in
PointerUnion.h:
// FIXME: Replace the uses of is(), get() and dyn_cast() with
// isa<T>, cast<T> and the llvm::dyn_cast<T>
Literal migration would result in dyn_cast_if_present (see the
definition of PointerUnion::dyn_cast), but this patch uses cast
because we know expect isa<Symbol *>(rel.referent) to be true.
