Don't early return from layoutMemory in PIC mode before we have set the
memory limits.
This matters in particular with shared-memory + PIC because shared
memories require maximum size.
Secondly, when we need a maximum, but the user does not supply one,
default to MAX_INT rather than 0 (defaulting to zero is completely
useless and means that building with -shared didn't previously work at
all without --maximum-memory, because zero is never big enough).
This is part of an ongoing effort to enable dynamic linking with
threads in emscripten.
See https://github.com/emscripten-core/emscripten/issues/3494
Differential Revision: https://reviews.llvm.org/D92528
The conditional guarding createInitMemoryFunction was incorrect and
didn't match that guarding the creation of the associated symbol.
Rather that reproduce the same conditions in multiple places we can
simply use the presence of the associated symbol.
Also, add an assertion that would have caught this bug.
Also, add a new test for this flag combination.
This is part of an ongoing effort to enable dynamic linking with
threads in emscripten.
See https://github.com/emscripten-core/emscripten/issues/3494
Differential Revision: https://reviews.llvm.org/D92520
Under existing behavior discarded functions are relocated to have the start pc
0. This causes problems when debugging as they typically overlap the first
function and lldb symbol resolution frequently chooses a discarded function
instead of the correct one. Using the value -1 or -2 (depending on which DWARF
section we are writing) is sufficient to prevent lldb from resolving to these
symbols.
Reviewed By: MaskRay, yurydelendik, sbc100
Differential Revision: https://reviews.llvm.org/D91803
In addition, disallow `-lto-new-pass-manager` (see D79371).
Note: the ELF port has also adopted --no-lto-new-pass-manager
Reviewed By: aeubanks
Differential Revision: https://reviews.llvm.org/D92422
Without this extra flag we can't distingish between stub functions and
functions that happen to have address 0 (relative to __table_base).
Adding this flag bit the base symbol class actually avoids growing the
SymbolUnion struct which would not be true if we added it to the
FunctionSymbol subclass (due to bitbacking).
The previous approach of setting it's table index to zero worked for
normal static relocations but not for `-fPIC` code.
See https://github.com/emscripten-core/emscripten/issues/12819
Differential Revision: https://reviews.llvm.org/D92038
This commit factors out a WasmTableType definition from WasmTable, as is
the case for WasmGlobal and other data types. Also add support for
extracting the SymbolName for a table from the linking section's symbol
table.
Differential Revision: https://reviews.llvm.org/D91849
This is a more full featured version of ``--allow-undefined``.
The semantics of the different methods are as follows:
report-all:
Report all unresolved symbols. This is the default. Normally the
linker will generate an error message for each reported unresolved
symbol but the option ``--warn-unresolved-symbols`` can change this
to a warning.
ignore-all:
Resolve all undefined symbols to zero. For data and function
addresses this is trivial. For direct function calls, the linker
will generate a trapping stub function in place of the undefined
function.
import-functions:
Generate WebAssembly imports for any undefined functions. Undefined
data symbols are resolved to zero as in `ignore-all`. This
corresponds to the legacy ``--allow-undefined`` flag.
The plan is to followup with a new mode called `import-dynamic` which
allows for statically linked binaries to refer to both data and
functions symbols from the embedder.
Differential Revision: https://reviews.llvm.org/D79248
This adds `--[no-]color-diagnostics[=auto,never,always]` to
the MachO port and harmonizes the flag in the other ports:
- Consistently use MetaVarName
- Consistently document the non-eq version as alias of the eq version
- Use B<> in the ports that have it (no-op, shorter)
- Fix oversight in COFF port that made the --no flag have the wrong
prefix
Differential Revision: https://reviews.llvm.org/D91640
These relocations represent offsets from the __tls_base symbol.
Previously we were just using normal MEMORY_ADDR relocations and relying
on the linker to select a segment-offset rather and absolute value in
Symbol::getVirtualAddress(). Using an explicit relocation type allows
allow us to clearly distinguish absolute from relative relocations based
on the relocation information alone.
One place this is useful is being able to reject absolute relocation in
the PIC case, but still accept TLS relocations.
Differential Revision: https://reviews.llvm.org/D91276
Previously we limited the use of atomics and TLS to programs
linked with `--shared-memory`.
However, as of https://reviews.llvm.org/D79530 we now allow
programs that use atomic to be linked without `--shared-memory`.
For this to be useful we also want to all TLS usage in such
programs. In this case, since we know we are single threaded
we simply include the TLS data as a regular active segment
and create an immutable `__tls_base` global that point to the
start of this segment.
Fixes: https://github.com/emscripten-core/emscripten/issues/12489
Differential Revision: https://reviews.llvm.org/D91115
This field to represents the amount of static data needed by
an dynamic library or executable it should not include things
like heap or stack areas, which in the case of `-pie` are
not determined until runtime (e.g. __stack_pointer is imported).
Differential Revision: https://reviews.llvm.org/D90261
Adds more testing in basic-assembly.s and a new test tables.s.
Adds support to yaml reading and writing of tables as well.
Differential Revision: https://reviews.llvm.org/D88815
Followup on https://reviews.llvm.org/D85062 which ignores
entire library objects when no symbols are used within them.
This is shouldn't apply with `--whole-archive` since this
is specified to treat them like direct object inputs.
Differential Revision: https://reviews.llvm.org/D89290
This allows `__wasilibc_populate_libpreopen` to be GC'd in more cases
where it isn't needed, including when linked from Rust's libstd.
Differential Revision: https://reviews.llvm.org/D85062
This flag works in a similar way to the ELF linker in that it
will resolve any defined symbols to their local definition with
a shared library or -pie executable.
This flag has no effect on static linking.
Differential Revision: https://reviews.llvm.org/D89152
This adds support for new-style command support. In this mode, all exports
are considered command entrypoints, and the linker inserts calls to
`__wasm_call_ctors` and `__wasm_call_dtors` for all such entrypoints.
This enables support for:
- Command entrypoints taking arguments other than strings and return values
other than `int`.
- Multicall executables without requiring on the use of string-based
command-line arguments.
This new behavior is disabled when the input has an explicit call to
`__wasm_call_ctors`, indicating code not expecting new-style command
support.
This change does mean that wasm-ld no longer supports DCE-ing the
`__wasm_call_ctors` function when there are no calls to it. If there are no
calls to it, and there are ctors present, we assume it's wasm-ld's job to
insert the calls. This seems ok though, because if there are ctors present,
the program is expecting them to be called. This change affects the
init-fini-gc.ll test.
In particular allow explict exporting of `__stack_pointer` but
exclud this from `--export-all` to avoid requiring the mutable
globals feature whenenve `--export-all` is used.
This uncovered a bug in populateTargetFeatures regarding checking
if the mutable-globals feature is allowed.
See: https://github.com/WebAssembly/binaryen/issues/2934
Differential Revision: https://reviews.llvm.org/D88506
https://github.com/WebAssembly/threads/issues/144 updated the
WebAssembly threads proposal to make atomic operations on unshared memories
valid. This change updates the feature checking in the linker accordingly.
Production WebAssembly engines have recently been updated to allow this
behvaior, but after this change users who accidentally use atomics with unshared
memories on older versions of the engines will get validation errors at runtime
rather than link errors.
Differential Revision: https://reviews.llvm.org/D79530
In lit tests, we run each LLD invocation twice (LLD_IN_TEST=2), without shutting down the process in-between. This ensures a full cleanup is properly done between runs.
Only active for the COFF driver for now. Other drivers still use LLD_IN_TEST=1 which executes just one iteration with full cleanup, like before.
When the environment variable LLD_IN_TEST is unset, a shortcut is taken, only one iteration is executed, no cleanup for faster exit, like before.
A public API, lld::safeLldMain(), is also available when using LLD as a library.
Differential Revision: https://reviews.llvm.org/D70378
With https://reviews.llvm.org/D87537 we made it an error
to import or export a mutable global with the +mutable-globals
feature present. However the scan was of the entire symbol
table rather than just the imports or exports and the filter
didn't match exaclyt meaning the `__stack_pointer` (a mutable
global) was always triggering with error when the `--export-all`
flag was used.
This also revealed that we didn't have any test coverage for
the `--export-all` flag.
This change fixes the current breakage on the emscripten-releases
roller.
Differential Revision: https://reviews.llvm.org/D87663
Also add the +mutable-globals features in clang when
building with `-fPIC` since the linker will generate mutable
globals imports and exports in that case.
Differential Revision: https://reviews.llvm.org/D87537
When a weak reference of a lazy symbol occurs we were not correctly
updating the lazy symbol. We need to tag the existing lazy symbol
as weak and, in the case of a function symbol, give it a signature.
Without the signature we can't then create the dummy function which
is needed when an weakly undefined function is called.
We had tests for weakly referenced lazy symbols but we were only
tests in the case where the reference was seen before the lazy
symbol.
See: https://github.com/WebAssembly/wasi-libc/pull/214
Differential Revision: https://reviews.llvm.org/D85567
The `intrinsics_gen` target exists in the CMake exports since r309389
(see LLVMConfig.cmake.in), hence projects can depend on `intrinsics_gen`
even it they are built separately from LLVM.
Reviewed By: MaskRay, JDevlieghere
Differential Revision: https://reviews.llvm.org/D83454
Accounting for the fact that Wasm function indices are 32-bit, but in wasm64 we want uniform 64-bit pointers.
Includes reloc types for 64-bit table indices.
Differential Revision: https://reviews.llvm.org/D83729
Include the archive name as well as the member name when an error
is encountered parsing bitcode archives.
Differential Revision: https://reviews.llvm.org/D82884
The meaning of -shared and -pie are expected to be changed in the
future when Module Linking-style libraries are implemented. Begin
issuing warnings to give people a heads-up that they will be changing.
For compatibility with Emscripten, add a --experimental-pic flag which
disables these warnings.
Differential Revision: https://reviews.llvm.org/D81760
Some projects use the constructor attribute on functions that also
return values. In this case we just ignore them.
The error was reported in the libgpg-error project that marks
gpg_err_init with the `__constructor__` attribute.
Differential Revision: https://reviews.llvm.org/D81962
This adds 4 new reloc types.
A lot of code that previously assumed any memory or offset values could be contained in a uint32_t (and often truncated results from functions returning 64-bit values) have been upgraded to uint64_t. This is not comprehensive: it is only the values that come in contact with the new relocation values and their dependents.
A new tablegen mapping was added to automatically upgrade loads/stores in the assembler, which otherwise has no way to select for these instructions (since they are indentical other than for the offset immediate). It follows a similar technique to https://reviews.llvm.org/D53307
Differential Revision: https://reviews.llvm.org/D81704
Previously in the object format we punted on this and simply wrote
zeros (and didn't include the function in the elem segment). With
this change we write a meaningful value which is the segment
relative table index of the associated function.
This matches the that wasm-ld produces in `-r` mode. This inconsistency
between the output the MC object writer and the wasm-ld object
writer could cause warnings to be emitted when reading back in the
output of `wasm-ld -r`. See:
https://github.com/emscripten-core/emscripten/issues/11217
This only applies to this one relocation type which is only generated
when compiling in PIC mode.
Differential Revision: https://reviews.llvm.org/D80774
Summary:
This patch fixes a bug where initialization code for .bss segments was
emitted in the memory initialization function even though the .bss
segments were discounted in the datacount section and omitted in the
data section. This was producing invalid binaries due to out-of-bounds
segment indices on the memory.init and data.drop instructions that
were trying to operate on the nonexistent .bss segments.
Reviewers: sbc100
Subscribers: dschuff, jgravelle-google, aheejin, sunfish, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D80354
This is a followup to https://reviews.llvm.org/D78779.
When signatures mismatch we create set of variant symbols. Some of
the fields in these symbols were not be initialized correct.
Specifically we were seeing isUsedInRegularObj not being set correctly,
leading to the symbol not getting included in the symbol table
and a crash writing relections in --reloctable mode.
There is larger refactor due here, but this is a minimal change the
fixes the bug at hand.
Differential Revision: https://reviews.llvm.org/D79756
Summary:
The WebAssembly backend automatically lowers atomic operations and TLS
to nonatomic operations and non-TLS data when either are present and
the atomics or bulk-memory features are not present, respectively. The
resulting object is no longer thread-safe, so the linker has to be
told not to allow it to be linked into a module with shared
memory. This was previously done by disallowing the 'atomics' feature,
which prevented any objct with its atomic operations or TLS removed
from being linked with any object containing atomics or TLS, and
therefore preventing it from being linked into a module with shared
memory since shared memory requires atomics.
However, as of https://github.com/WebAssembly/threads/issues/144, the
validation rules are relaxed to allow atomic operations to validate
with unshared memories, which makes it perfectly safe to link an
object with stripped atomics and TLS with another object that still
contains TLS and atomics as long as the resulting module has an
unshared memory. To allow this kind of link, this patch disallows a
pseudo-feature 'shared-mem' rather than 'atomics' to communicate to
the linker that the object is not thread-safe. This means that the
'atomics' feature is available to accurately reflect whether or not an
object has atomics enabled.
As a drive-by tweak, this change also requires that bulk-memory be
enabled in addition to atomics in order to use shared memory. This is
because initializing shared memories requires bulk-memory operations.
Reviewers: aheejin, sbc100
Subscribers: dschuff, jgravelle-google, hiraditya, sunfish, jfb, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D79542
Sam Clegg