Commit Graph

511 Commits

Author SHA1 Message Date
Sam Clegg 9d1409df87 [lld][WebAssembly] Give better warnings on bad relocation sites
Differential Revision: https://reviews.llvm.org/D90443
2020-10-30 10:11:04 -07:00
Wouter van Oortmerssen b8c2d60df5 [WebAssembly] Improved LLD error messages in case of mixed wasm32/wasm64 object files
Differential Revision: https://reviews.llvm.org/D90428
2020-10-29 17:15:59 -07:00
Sam Clegg 84129150ce [lld][WebAssembly] Fix memory size in dylink section for -pie exectuables
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
2020-10-27 16:05:52 -07:00
Paulo Matos 388fb67b0d [WebAssembly] Added .tabletype to asm and multiple table support in obj files
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
2020-10-13 07:52:23 -07:00
Sam Clegg b3b4cda104 [lld][WebAssembly] Don't GC library objects under `--whole-archive`
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
2020-10-12 21:19:19 -07:00
Dan Gohman 950ae43091 [WebAssembly] GC constructor functions in otherwise unused archive objects
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
2020-10-12 18:54:57 -07:00
Sam Clegg 2513407d39 [lld][WebAssembly] Add support for -Bsymbolic flag
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
2020-10-12 17:25:04 -07:00
Dan Gohman 6cd8511e59 [WebAssembly] New-style command support
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.
2020-09-30 19:02:40 -07:00
Sam Clegg 3c45a06f26 [lld][WebAssembly] Allow exporting of mutable globals
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
2020-09-30 17:53:27 -07:00
Benjamin Kramer b59dff4b16 [wasm] Move WasmTraits.h to BinaryFormat
There's no dependency on Object in there and this avoids a cyclic
dependency between libMC and libObject.
2020-09-28 22:07:28 +02:00
Thomas Lively 15a5e86fb3 [lld][WebAssembly] Allow `atomics` feature with unshared memory
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
2020-09-24 20:35:29 -07:00
Alexandre Ganea f2efb5742c [LLD][COFF] Cover usage of LLD-as-a-library in tests
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
2020-09-24 15:07:50 -04:00
Fangrui Song 51b75b87db [lld][WebAssembly] Fix -Wunused-variable after D87663 2020-09-18 16:10:39 -07:00
Sam Clegg 3f411e9773 [lld][WebAssembly] Fix --export-all when __stack_pointer is present
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
2020-09-15 06:17:01 -07:00
Sam Clegg 2c12b056be [lld][WebAssembly] Allow globals imports via import_name/import_module
This feature already exists but was limited to function
symbols.

Differential Revision: https://reviews.llvm.org/D87666
2020-09-14 20:35:03 -07:00
Sam Clegg cc2da5554b [lld][WebAssembly] Add initial support for -Map/--print-map
Differential Revision: https://reviews.llvm.org/D77187
2020-09-12 16:10:51 -07:00
Sam Clegg 04febd30a8 [lld][WebAssembly] Error on import/export of mutable global without `mutable-globals` feature
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
2020-09-12 14:28:14 -07:00
Samuel Kostial 304264e73d [lld][WebAssembly] Emit all return types of multivalue functions
We previously were incorrectly emitting only the first result type.

Differential Revision: https://reviews.llvm.org/D85783
2020-08-12 13:14:15 -07:00
Wouter van Oortmerssen b52fc59e17 [WebAssembly] Fixed memory.init always using 64-bit ptr
(because the is64 flag was tested incorrectly in LLD).
2020-08-12 12:23:36 -07:00
Wouter van Oortmerssen 582fd474dd [WebAssembly] wasm64: fix memory.init operand types
I had assumed they would all become in i64, but this is not necessary as long as data segments stay 32-bit, see:
https://github.com/WebAssembly/memory64/blob/master/proposals/memory64/Overview.md

Differential Revision: https://reviews.llvm.org/D85552
2020-08-10 10:15:20 -07:00
Sam Clegg b34ec5969f [lld][WebAssembly] Handle weakly referenced symbols when lazy (archive) version is see first
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
2020-08-10 08:16:55 -07:00
Michele Scandale 53880b8cb9 [CMake] Make `intrinsics_gen` dependency unconditional.
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
2020-07-17 16:43:17 -07:00
Wouter van Oortmerssen cc1b9b680f [WebAssembly] 64-bit (function) pointer fixes.
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
2020-07-16 14:10:22 -07:00
Wouter van Oortmerssen 29f8c9f6c2 [WebAssembly] Triple::wasm64 related cleanup
Differential Revision: https://reviews.llvm.org/D83713
2020-07-16 12:01:10 -07:00
Wouter van Oortmerssen 4d135b0446 [WebAssembly] 64-bit memory limits 2020-07-06 12:40:45 -07:00
Sam Clegg 73e575a88e [lld][WebAssembly] Give better error message on bad archive member
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
2020-06-30 21:36:36 -07:00
Dan Gohman 46a3268312 [WebAssembly] Add warnings for -shared and -pie
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
2020-06-25 15:55:46 -07:00
Wouter van Oortmerssen b9a539c010 [WebAssembly] Adding 64-bit versions of __stack_pointer and other globals
We have 6 globals, all of which except for __table_base are 64-bit under wasm64.

Differential Revision: https://reviews.llvm.org/D82130
2020-06-25 15:52:44 -07:00
Sam Clegg 79aad89d8d [WebAssembly] Add support for externalref to MC and wasm-ld
This allows code for handling externref values to be processed by the
assembler and linker.

Differential Revision: https://reviews.llvm.org/D81977
2020-06-22 15:57:24 -07:00
Sam Clegg 21e14cce23 [lld][WebAssembly] Allow ctors functions that return values
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
2020-06-18 13:11:40 -07:00
Wouter van Oortmerssen 3b29376e3f [WebAssembly] Adding 64-bit version of R_WASM_MEMORY_ADDR_* relocs
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
2020-06-15 10:07:42 -07:00
Sam Clegg 81443ac1bc [WebAssembly] Add placeholders for R_WASM_TABLE_INDEX_REL_SLEB relocations
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
2020-05-29 10:57:26 -07:00
Thomas Lively d851fce4cb [lld][WebAssembly] Do not emit initialization for .bss segments
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
2020-05-21 11:33:25 -07:00
Sam Clegg 064e9907ba [lld][WebAssembly] Fix for --relocatable and signature mismatches
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
2020-05-13 10:27:09 -07:00
Thomas Lively a1ae9566ea [WebAssembly] Disallow 'shared-mem' rather than 'atomics'
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
2020-05-08 13:52:39 -07:00
Sam Clegg f03b6e785b [lld][WebAssembly] Honor --allow-undefined for data symbols too
This was originally the way this worked before before
https://reviews.llvm.org/D60882.

In retrospect it seems inconsistent that `--allow-undefined` doesn't
work for all symbols.  See:
https://groups.google.com/g/emscripten-discuss/c/HSRgQiIq1gI/m/Kt9oFWHiAwAJ

I'm also planning a followup change which implement the full
`--unresolved-symbols=..` flags supported by ELF linkers (both ld and
ld.lld) since it seems more standard.

Differential Revision: https://reviews.llvm.org/D79247
2020-05-06 12:39:29 -07:00
Reid Kleckner 932f0276ea [Support] Move LLD's parallel algorithm wrappers to support
Essentially takes the lld/Common/Threads.h wrappers and moves them to
the llvm/Support/Paralle.h algorithm header.

The changes are:
- Remove policy parameter, since all clients use `par`.
- Rename the methods to `parallelSort` etc to match LLVM style, since
  they are no longer C++17 pstl compatible.
- Move algorithms from llvm::parallel:: to llvm::, since they have
  "parallel" in the name and are no longer overloads of the regular
  algorithms.
- Add range overloads
- Use the sequential algorithm directly when 1 thread is requested
  (skips task grouping)
- Fix the index type of parallelForEachN to size_t. Nobody in LLVM was
  using any other parameter, and it made overload resolution hard for
  for_each_n(par, 0, foo.size(), ...) because 0 is int, not size_t.

Remove Threads.h and update LLD for that.

This is a prerequisite for parallel public symbol processing in the PDB
library, which is in LLVM.

Reviewed By: MaskRay, aganea

Differential Revision: https://reviews.llvm.org/D79390
2020-05-05 15:21:05 -07:00
Sam Clegg 0a6c4d8d2e [WebAssmebly] Add support for defined wasm globals in MC and lld
This change add support for defined wasm globals in the .s format,
the MC layer, and wasm-ld

Currently there is no support custom initialization and all wasm
globals are initialized to zero.

Fixes: PR45742

Differential Revision: https://reviews.llvm.org/D79137
2020-04-30 12:43:15 -07:00
Sam Clegg 4b8e2d8e81 [lld][WebAssembly] Fix crash on function signature mismatch with --relocatable
These stub new function were not being added to the symbol table
which in turn meant that we were crashing when trying to output
relocations against them.

Differential Revision: https://reviews.llvm.org/D78779
2020-04-25 10:26:11 -07:00
Wouter van Oortmerssen cbf99e0fba [WebAssembly] Fix faulty logic in verifyRelocTargets 2020-04-16 18:19:56 -07:00
Wouter van Oortmerssen 48139ebc3a [WebAssembly] Add int32 DW_OP_WASM_location variant
This to allow us to add reloctable global indices as a symbol.
Also adds R_WASM_GLOBAL_INDEX_I32 relocation type to support it.

See discussion in https://github.com/WebAssembly/debugging/issues/12
2020-04-16 16:32:17 -07:00
Thomas Lively 6474d1b20e [lld][WebAssembly] Do not require --shared-memory with --relocatable
Summary:
wasm-ld requires --shared-memory to be passed when the atomics feature
is enabled because historically atomic operations were only valid with
shared memories. This change relaxes that requirement for when
building relocatable objects because their memories are not
meaningful. This technically maintains the validity of object files
because the threads spec now allows atomic operations with unshared
memories, although we don't support that elsewhere in the tools yet.

This fixes and Emscripten build issue reported at
https://bugs.chromium.org/p/webp/issues/detail?id=463.

Reviewers: sbc100

Subscribers: dschuff, jgravelle-google, aheejin, sunfish, jfb, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D78072
2020-04-14 13:49:28 -07:00
Sam Clegg 3ea1c62cba [WebAssembly] Emit .llvmcmd and .llvmbc as custom sections
Fixes: https://bugs.llvm.org/show_bug.cgi?id=45362

Differential Revision: https://reviews.llvm.org/D77115
2020-04-14 13:24:18 -07:00
Georgii Rymar 1647ff6e27 [ADT/STLExtras.h] - Add llvm::is_sorted wrapper and update callers.
It can be used to avoid passing the begin and end of a range.
This makes the code shorter and it is consistent with another
wrappers we already have.

Differential revision: https://reviews.llvm.org/D78016
2020-04-14 14:11:02 +03:00
Thomas Lively c496d84b4f [lld][WebAssembly] Handle 4gb max memories
Summary:
A previous change (53211a) had updated the argument parsing to handle
large max memories, but 4294967296 would still wrap to zero after the
options were parsed. This change updates the configuration to use a
64-bit integer to store the max memory to avoid that overflow.

Reviewers: sbc100

Subscribers: dschuff, jgravelle-google, aheejin, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77437
2020-04-09 13:06:41 -07:00
Heejin Ahn c09acd5dd1 [WebAssembly] Handle event exports
Summary: This handles exports of events, which was missing.

Reviewers: sbc100

Subscribers: dschuff, jgravelle-google, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77566
2020-04-06 11:28:38 -07:00
Kazuaki Ishizaki 7c5fcb3591 [lld] NFC: fix trivial typos in comments
Differential Revision: https://reviews.llvm.org/D72339
2020-04-02 01:21:36 +09:00
Sam Clegg b5767010a8 [lld][WebAssembly] Early error if output file cannot be created.
This matches the behaviour of the ELF driver.

Also move the `createFiles` to be `checkConfig` and report `no input
files` there.   Again this is mostly to match the structure of the ELF
linker better.

Differential Revision: https://reviews.llvm.org/D76960
2020-03-31 21:42:38 -07:00
Fangrui Song eb4663d8c6 [lld][COFF][ELF][WebAssembly] Replace --[no-]threads /threads[:no] with --threads={1,2,...} /threads:{1,2,...}
--no-threads is a name copied from gold.
gold has --no-thread, --thread-count and several other --thread-count-*.

There are needs to customize the number of threads (running several lld
processes concurrently or customizing the number of LTO threads).
Having a single --threads=N is a straightforward replacement of gold's
--no-threads + --thread-count.

--no-threads is used rarely. So just delete --no-threads instead of
keeping it for compatibility for a while.

If --threads= is specified (ELF,wasm; COFF /threads: is similar),
--thinlto-jobs= defaults to --threads=,
otherwise all available hardware threads are used.

There is currently no way to override a --threads={1,2,...}. It is still
a debate whether we should use --threads=all.

Reviewed By: rnk, aganea

Differential Revision: https://reviews.llvm.org/D76885
2020-03-31 08:46:12 -07:00
Alexandre Ganea 09158252f7 [ThinLTO] Allow usage of all hardware threads in the system
Before this patch, it wasn't possible to extend the ThinLTO threads to all SMT/CMT threads in the system. Only one thread per core was allowed, instructed by usage of llvm::heavyweight_hardware_concurrency() in the ThinLTO code. Any number passed to the LLD flag /opt:lldltojobs=..., or any other ThinLTO-specific flag, was previously interpreted in the context of llvm::heavyweight_hardware_concurrency(), which means SMT disabled.

One can now say in LLD:
/opt:lldltojobs=0 -- Use one std::thread / hardware core in the system (no SMT). Default value if flag not specified.
/opt:lldltojobs=N -- Limit usage to N threads, regardless of usage of heavyweight_hardware_concurrency().
/opt:lldltojobs=all -- Use all hardware threads in the system. Equivalent to /opt:lldltojobs=$(nproc) on Linux and /opt:lldltojobs=%NUMBER_OF_PROCESSORS% on Windows. When an affinity mask is set for the process, threads will be created only for the cores selected by the mask.

When N > number-of-hardware-threads-in-the-system, the threads in the thread pool will be dispatched equally on all CPU sockets (tested only on Windows).
When N <= number-of-hardware-threads-on-a-CPU-socket, the threads will remain on the CPU socket where the process started (only on Windows).

Differential Revision: https://reviews.llvm.org/D75153
2020-03-27 10:20:58 -04:00