Commit Graph

366 Commits

Author SHA1 Message Date
Mikhail Goncharov 47c17bcd0e [lld] Use %t file in test
Otherwise it fails in some setups when creation of "out.wasm" is not possible.

Differential Revision: https://reviews.llvm.org/D91521
2020-11-16 10:49:38 +01:00
Sam Clegg a28a466210 [WebAssembly] Add new relocation type for TLS data symbols
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
2020-11-13 07:59:29 -08:00
Sam Clegg b646e8b154 [lld][WebAssembly] Add test for TLS BSS data. NFC.
Differential Revision: https://reviews.llvm.org/D91231
2020-11-13 07:52:18 -08:00
Sam Clegg 29a3056bb5 [lld][WebAssembly] Allow references to __tls_base without shared memory
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
2020-11-10 17:58:06 -08:00
Sam Clegg 504cb2730c [lld][WebAssembly] Convert TLS tests to asm format
Fix a corresponding bug in WasmAsmParser around parsing.tdata sections.

Differential Revision: https://reviews.llvm.org/D91113
2020-11-10 11:38:53 -08:00
Sam Clegg 1800b44651 [lld][WebAssembly] Remove bad-reloc test
This test was checking behaviour that only exists in the debug
configuration so will fail in release builds.

Perhaps there is way to keep this test around and only run
it in debug builds but for now I'm removing so fix the
release builders.

Differential Revision: https://reviews.llvm.org/D90542
2020-10-31 16:42:55 -07:00
Reid Kleckner 09662eeb46 Fix lld/wasm test portability issue, and XFAIL the test
I don't see any warnings from lld.wasm locally. Needs more
investigation.
2020-10-31 11:19:28 -07:00
Ali Tamur ca55c99d56 [lld][WebAssembly] Do not specify temporary file name in tests.
bad-reloc.yaml test introduced at 9d1409df87 uses a name (out.wasm) to specify a
temporary output file name, which causes breakage in our system.
2020-10-30 18:27:28 -07:00
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
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
Petr Hosek 9c73e55510 Revert "[DebugInfo] Remove dots from getFilenameByIndex return value"
This is failing on Windows bots due to path separator normalization.

This reverts commit 042c235068.
2020-09-15 10:06:47 -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
Petr Hosek 58938b544b [NFC][DebugInfo] Use consistent regex group spelling
This is a follow up to c1f2fb5184.
2020-09-15 01:49:42 -07:00
Petr Hosek c1f2fb5184 [DebugInfo] Support both forward and backward slashes in tests
This addresses test failure revealed by 042c235068.
2020-09-15 00:59:58 -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
Sam Clegg e3e3d6eecf [lld][WebAssembly] Convert a objyaml-using test to assembly
Differential Revision: https://reviews.llvm.org/D87536
2020-09-11 14:48:37 -07:00
Sam Clegg fa2a8acc71 [WebAssembly] Add assembly syntax for mutable globals
This adds and optional ", immutable" to the end of a `.globaltype`
declaration.  I would have prefered to match the `.wat` syntax
where immutable is the default and `mut` is the signifier for
mutable globals.  Sadly changing the default would break backwards
compat with existing assembly in the wild so I think its best
to stick with this approach.

Differential Revision: https://reviews.llvm.org/D87515
2020-09-11 11:11:02 -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
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
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
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 d9e0bbd17b [WebAssembly] Adding 64-bit versions of all load & store ops.
Context: https://github.com/WebAssembly/memory64/blob/master/proposals/memory64/Overview.md
This is just a first step, adding the new instruction variants while keeping the existing 32-bit functionality working.
Some of the basic load/store tests have new wasm64 versions that show that the basics of the target are working.
Further features need implementation, but these will be added in followups to keep things reviewable.

Differential Revision: https://reviews.llvm.org/D80769
2020-06-15 08:31:56 -07:00
Sam Clegg fd1c894a4a [lld][WebAssembly] Convert some lld tests to assembly
When we originally wrote these tests we didn't have a stable and
fleshed out assembly format.  Now we do so we should prefer that
over llvm ir for lld tests to avoid including more part of llvm
than necessary in order to run the test.

This change converts just 30 out of about 130 test files. More to
come when I have some more time.

Differential Revision: https://reviews.llvm.org/D80361
2020-05-28 16:52:01 -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
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
Eli Friedman 875e26d343 Fix lld testcases I missed in D78413 (9b9454a) 2020-04-20 12:48:57 -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 9225ff6278 [lld][WebAssembly] Add test for --export of empty string
The actual bug was fixed in https://reviews.llvm.org/D74589

Differential Revision: https://reviews.llvm.org/D77084
2020-04-11 18:21:40 -07:00
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
Hans Wennborg 717a460867 Drop the number of thinlto jobs in some tests to avoid crashing on 32-bit windows 2020-04-07 09:52:12 +02:00
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
scentini 51d594d33c Replace output file name in test with %t 2020-04-01 16:40:02 +02:00
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
Dan Gohman 66bfbedbdf [WebAssembly] Support wasm exports with zero-length names.
Zero-length strings are valid export names in WebAssembly, so allow
users to specify them.

Differential Revision: https://reviews.llvm.org/D71793
2020-03-26 16:20:43 -07:00
Paolo Severini aff75e1a1f [lld][Wasm] Wasm-ld emits invalid .debug_ranges entries for non-live symbols
When the debug info contains a relocation against a dead symbol, wasm-ld
may emit spurious range-list terminator entries (entries with Start==0
and End==0). This change fixes this by emitting the WasmRelocation
Addend as End value for a non-live symbol.

Reviewed by: sbc100, dblaikie

Differential Revision: https://reviews.llvm.org/D74781
2020-03-26 14:26:31 -07:00
Heejin Ahn f033f201a7 [WebAssembly] Add test for event section order change
Summary:
This adds a test for D76752. Now the global section comes after the
event section, and this change makes sure it is satisfied.

Reviewers: sbc100, tlively

Reviewed By: tlively

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D76823
2020-03-26 11:05:24 -07:00
Sam Clegg 928e9e1723 [lld][WebAssembly] Add support for --rsp-quoting
This also changes to default style to match the host.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D75577
2020-03-04 11:41:33 -08:00
Sam Clegg a57f1a5435 [lld][WebAssembly] Handle mixed strong and weak undefined symbols
When there are both strong and weak references to an undefined
symbol ensure that the strong reference prevails in the output symbol
generating the correct error.

Test case copied from lld/test/ELF/weak-and-strong-undef.s

Differential Revision: https://reviews.llvm.org/D75322
2020-02-28 10:16:10 -08:00
Sam Clegg 06f1a5c9c2 [lld][WebAssembly] Allow symbols with explict import names to be undefined at link time.
Differential Revision: https://reviews.llvm.org/D74110
2020-02-19 18:02:49 -08:00
Sam Clegg b062fe1816 [lld][WebAssembly] Fail if bitcode objects are pulled in after LTO
This can happen if lto::LTO::getRuntimeLibcallSymbols doesn't return
an complete/accurate list of libcalls.  In this case new bitcode
object can be linked in after LTO.

For example the WebAssembly backend currently calls:
  setLibcallName(RTLIB::FPROUND_F32_F16, "__truncsfhf2");

But `__truncsfhf2` is not part of `getRuntimeLibcallSymbols` so if
this symbol is generated during LTO the link will currently fail.

Without this change the linker crashes because the bitcode symbol
makes it all the way to the output phase.

See: https://bugs.llvm.org/show_bug.cgi?id=44353

Differential Revision: https://reviews.llvm.org/D71632
2020-02-11 17:36:15 -08:00
Derek Schuff ff171acf84 [WebAssembly] Track frame registers through VReg and local allocation
This change has 2 components:

Target-independent: add a method getDwarfFrameBase to TargetFrameLowering. It
describes how the Dwarf frame base will be encoded.  That can be a register (the
default), the CFA (which replaces NVPTX-specific logic in DwarfCompileUnit), or
a DW_OP_WASM_location descriptr.

WebAssembly: Allow WebAssemblyFunctionInfo::getFrameRegister to return the
correct virtual register instead of FP32/SP32 after WebAssemblyReplacePhysRegs
has run.  Make WebAssemblyExplicitLocals store the local it allocates for the
frame register. Use this local information to implement getDwarfFrameBase

The result is that the DW_AT_frame_base attribute is correctly encoded for each
subprogram, and each param and local variable has a correct DW_AT_location that
uses DW_OP_fbreg to refer to the frame base.

This is a reland of rG3a05c3969c18 with fixes for the expensive-checks
and Windows builds

Differential Revision: https://reviews.llvm.org/D71681
2020-01-17 17:23:56 -08:00
Sam Clegg 51b521c07a [lld][WebAssembly] Use a more meaningful name for stub functions
When we generate these stub functions on signature mismatches give
them a more meaningful name so that when people see this in stack
traces is gives a clue as the what is going on.

See: https://github.com/emscripten-core/emscripten/issues/10226

Differential Revision: https://reviews.llvm.org/D72881
2020-01-16 14:55:37 -08:00
Derek Schuff 80906d9d16 Revert "[WebAssembly] Track frame registers through VReg and local allocation"
This reverts commit 3a05c3969c.
It breaks under expensive-checks and on Windows
2020-01-16 14:38:00 -08:00
Derek Schuff 3a05c3969c [WebAssembly] Track frame registers through VReg and local allocation
This change has 2 components:

Target-independent: add a method getDwarfFrameBase to TargetFrameLowering. It
describes how the Dwarf frame base will be encoded.  That can be a register (the
default), the CFA (which replaces NVPTX-specific logic in DwarfCompileUnit), or
a DW_OP_WASM_location descriptr.

WebAssembly: Allow WebAssemblyFunctionInfo::getFrameRegister to return the
correct virtual register instead of FP32/SP32 after WebAssemblyReplacePhysRegs
has run.  Make WebAssemblyExplicitLocals store the local it allocates for the
frame register. Use this local information to implement getDwarfFrameBase

The result is that the DW_AT_frame_base attribute is correctly encoded for each
subprogram, and each param and local variable has a correct DW_AT_location that
uses DW_OP_fbreg to refer to the frame base.

Differential Revision: https://reviews.llvm.org/D71681
2020-01-16 13:51:17 -08:00
Sam Clegg 9cd985815a [lld][WebAssembly] Add libcall symbols to the link when LTO is being used.
This code is copied almost verbatim from the equivalent change to the
ELF linker:

- https://reviews.llvm.org/D50017
- https://reviews.llvm.org/D50475

The upshot is that libraries containing libcall (such as compiler-rt
and libc) can be compiled with LTO.

Fixes PR41384

Differential Revision: https://reviews.llvm.org/D71738
2020-01-10 11:01:05 -08:00
Kazuaki Ishizaki 7ae3d33546 [lld] Fix trivial typos in comments
Reviewed By: ruiu, MaskRay

Differential Revision: https://reviews.llvm.org/D72196
2020-01-06 10:25:48 -08:00
Fangrui Song a36ddf0aa9 Migrate function attribute "no-frame-pointer-elim"="false" to "frame-pointer"="none" as cleanups after D56351 2019-12-24 16:27:51 -08:00
Sam Clegg 881d877846 [WebAssembly] Add new `export_name` clang attribute for controlling wasm export names
This is equivalent to the existing `import_name` and `import_module`
attributes which control the import names in the final wasm binary
produced by lld.

This maps the existing

This attribute currently requires a string rather than using the
symbol name for a couple of reasons:

1. Avoid confusion with static and dynamic linking which is
   based on symbol name.  Exporting a function from a wasm module using
   this directive is orthogonal to both static and dynamic linking.
2. Avoids name mangling.

Differential Revision: https://reviews.llvm.org/D70520
2019-12-11 11:54:57 -08:00
Sam Clegg b4f4e370b5 [WebAssebmly][MC] Support .import_name/.import_field asm directives
Convert the MC test to use asm rather than bitcode.

This is a precursor to https://reviews.llvm.org/D70520.

Differential Revision: https://reviews.llvm.org/D70877
2019-12-06 15:09:56 -08:00
Sam Clegg baff8ec2e1 [WebAssembly][lld] Fix for static linking of PIC code
When statically linking PIC code we create an internalized __memory_base
so that memory-base-relative relocation work correctly.  The value of
this global should be zero, and not the globalBase since the globalBase
offset is already taken into account by getVirtualAddress.

Fixes: https://github.com/emscripten-core/emscripten/issues/9013

Differential Revision: https://reviews.llvm.org/D69600
2019-10-29 18:58:56 -07:00
Thomas Lively 393d0f799f [WebAssembly] Allow multivalue signatures in object files
Summary:
Also changes the wasm YAML format to reflect the possibility of having
multiple return types and to put the returns after the params for
consistency with the binary encoding.

Reviewers: aheejin, sbc100

Subscribers: dschuff, jgravelle-google, hiraditya, sunfish, arphaman, rupprecht, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D69156

llvm-svn: 375283
2019-10-18 20:27:30 +00:00
Sam Clegg 67b055841f [lld][WebAssebmly] Preserve custom import attributes with LTO
Undefined symbols in WebAssembly can come with custom `import-module`
and `import-field` attributes.  However when reading symbols from
bitcode object files during LTO those curtom attributes are not
available.

Once we compile the LTO object and read in the symbol table from the
object file we have access to these custom attributes.  In this case,
when undefined symbols are added and a symbol already exists in the
SymbolTable we can't simple return it, we may need to update the
symbol's attributes.

Fixes: PR43211

Differential Revision: https://reviews.llvm.org/D68959

llvm-svn: 375081
2019-10-17 05:16:54 +00:00
Sam Clegg 6c393e9d74 [lld][WebAssembly] Fix for weak references to data symbols in archives
Fix a bug where were not handling relocations against weakly undefined
data symbol.  Add a test for this case.  Also ensure that the weak
references to data symbols are not pulled in from archive files by
default (but are if `-u <name>` is added to the command line).

Fixes: PR43696

Differential Revision: https://reviews.llvm.org/D69073

llvm-svn: 375077
2019-10-17 03:21:02 +00:00
Thomas Lively 190dacc3cc [WebAssembly] Elide data segments for .bss sections
Summary:
WebAssembly memories are zero-initialized, so when module does not
import its memory initializing .bss sections is guaranteed to be a
no-op. To reduce binary size and initialization time, .bss sections
are simply not emitted into the final binary unless the memory is
imported.

Reviewers: sbc100

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68965

llvm-svn: 374940
2019-10-15 19:05:11 +00:00
James Clarke 1ab27c74d4 [lld][WebAssembly] Fix static linking of -fPIC code with external undefined data
Reviewers: ruiu, sbc100

Reviewed By: sbc100

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68991

llvm-svn: 374913
2019-10-15 17:05:42 +00:00
Sam Clegg 937b955837 [lld][WebAssembly] Fix static linking of -fPIC code with external undefined functions
Differential Revision: https://reviews.llvm.org/D66784

llvm-svn: 372779
2019-09-24 20:52:12 +00:00
Sam Clegg f6f4b98f03 [lld][WebAssembly] Preserve symbol flags in --relocatable output
Fixes https://github.com/emscripten-core/emscripten/issues/8879

Differential Revision: https://reviews.llvm.org/D67729

llvm-svn: 372660
2019-09-23 21:28:29 +00:00
Thomas Lively 21143b93a6 [WebAssembly] Sort output data sections to place .bss last
Summary:
This was always the intended behavior, but had not been
implemented. This ordering is important for Emscripten when generating
.mem files while compiling to JS, since only zeros at the end of
initialized memory can be dropped.

Fixes https://github.com/emscripten-core/emscripten/issues/8999

Reviewers: sbc100

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67736

llvm-svn: 372284
2019-09-19 01:14:59 +00:00
Amy Huang 7b1d793713 Reland "Change the X86 datalayout to add three address spaces
for 32 bit signed, 32 bit unsigned, and 64 bit pointers."
This reverts 57076d3199.

Original review at https://reviews.llvm.org/D64931.
Review for added fix at https://reviews.llvm.org/D66843.

llvm-svn: 371568
2019-09-10 23:15:38 +00:00
Thomas Lively 09768c5d7a [WebAssembly] Initialize memory in start function
Summary:
 - `__wasm_init_memory` is now the WebAssembly start function instead
   of being called from `__wasm_call_ctors` or called directly by the
   runtime.
 - Adds a new synthetic data symbol `__wasm_init_memory_flag` that is
   atomically incremented from zero to one by the thread responsible
   for initializing memory.
 - All threads now unconditionally perform data.drop on all passive
   segments.
 - Removes --passive-segments and --active-segments flags and controls
   segment type based on --shared-memory instead. The deleted flags
   were only present to ameliorate the upgrade path in Emscripten.

Reviewers: sbc100, aheejin

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65783

llvm-svn: 370965
2019-09-04 19:50:39 +00:00
Sam Clegg fecfc5920a [lld][WebAssembly] Fix spurious signature mismatch warnings
Summary:
This a follow up on: https://reviews.llvm.org/D62153

Handle the case where there are multiple object files that contain
undefined references to the same function.  We only generate a function
variant if the existing symbol is directly called.

See: https://github.com/emscripten-core/emscripten/issues/8995

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67015

llvm-svn: 370509
2019-08-30 19:50:59 +00:00
Dan Gohman 7cb9c8a506 [WebAssembly] Implement NO_STRIP
This patch implements support for the NO_STRIP flag, which will allow
__attribute__((used)) to be implemented.

This accompanies https://reviews.llvm.org/D62542, which moves to setting the
NO_STRIP flag, and will continue to set EXPORTED for Emscripten targets for
compatibility.

Differential Revision: https://reviews.llvm.org/D66968

llvm-svn: 370416
2019-08-29 22:41:05 +00:00
Vlad Tsyrklevich 57076d3199 Revert "Change the X86 datalayout to add three address spaces for 32 bit signed,"
This reverts commit r370083 because it caused check-lld failures on
sanitizer-x86_64-linux-fast.

llvm-svn: 370142
2019-08-28 01:08:54 +00:00
Jacob Gravelle 92ed86d239 [lld][WebAssembly] Support for growable tables
Adds --growable-table flag to handle building wasm modules with tables
that can grow.

Wasm tables that we use to store function pointers. In order to add functions
to that table at runtime, we need to either preallocate space, or grow the table.
In order to specify a table with no maximum size, we need some flag to handle
that case, separately from a potential --max-table-size= flag.

Note that the number of elements in the table isn't knowable until link-time,
so it's unclear if we will want a --max-table-size= flag in the future.

llvm-svn: 370127
2019-08-27 22:58:21 +00:00
Amy Huang 1299945b81 Change the X86 datalayout to add three address spaces for 32 bit signed,
32 bit unsigned, and 64 bit pointers.

llvm-svn: 370083
2019-08-27 17:46:53 +00:00
Sam Clegg 040ef1091d [lld][WebAssembly] Create optional symbols after handling --export/--undefined
Handling of --export/--undefined can pull in lazy symbols which in turn
can pull in referenced to optional symbols.  We need to delay the
creation of optional symbols until all possible references to them have
been created.

Differential Revision: https://reviews.llvm.org/D66768

llvm-svn: 370012
2019-08-27 04:27:57 +00:00
Sam Clegg cf2b8722d4 [WebAssembly][lld] Fix crash when applying relocations to debug sections
Debug sections are special in that they can contain relocations against
symbols that are not present in the final output (i.e. not live).
However it is also possible to have R_WASM_TABLE_INDEX relocations
against symbols that don't have a table index assigned (since they are
not address taken by actual code.

Fixes: https://github.com/emscripten-core/emscripten/issues/9023

Differential Revision: https://reviews.llvm.org/D66435

llvm-svn: 369423
2019-08-20 18:39:24 +00:00
Sam Clegg e8e914e640 [lld][WebAssembly] Honor --no-export-dynamic even with -shared
Differential Revision: https://reviews.llvm.org/D66359

llvm-svn: 369276
2019-08-19 16:34:51 +00:00
Sam Clegg 7185a7301e [lld][WebAssembly] Allow linking of pic code into static binaries
Summary: See https://github.com/emscripten-core/emscripten/issues/9013

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65922

llvm-svn: 368719
2019-08-13 17:02:02 +00:00
Sam Clegg caa0db1318 [lld][WebAssembly] Add optional symbols after input file handling
This allows undefined references in input files be resolved by the
optional symbols.  Previously we were doing this before input file
reading which means it was working only for command line symbols
references (i.e. -u or --export).

Also use addOptionalDataSymbol for __dso_handle and make all optional
symbols hidden by default.

Differential Revision: https://reviews.llvm.org/D65920

llvm-svn: 368310
2019-08-08 16:58:36 +00:00
Guanzhong Chen 0cb776e61a [WebAssembly] Fix null pointer in createInitTLSFunction
Summary:
`createSyntheticSymbols`, which creates `WasmSym::InitTLS`, is only called
when `!config->relocatable`, but this condition is not checked when calling
`createInitTLSFunction`.

This diff checks `!config->relocatable` before calling `createInitTLSFunction`.

Fixes https://github.com/emscripten-core/emscripten/issues/9155.

Reviewers: tlively, aheejin, kripken, sbc100

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65785

llvm-svn: 368078
2019-08-06 20:09:04 +00:00
Guanzhong Chen 87186b2447 [WebAssembly] Set __tls_align to 1 when there is no TLS
Summary:
We want the tool conventions to state that `__tls_align` will be a power of 2.
It makes sense to not have an exception for when there is no TLS.

Reviewers: tlively, sunfish

Reviewed By: tlively

Subscribers: dschuff, sbc100, jgravelle-google, aheejin, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65177

llvm-svn: 366948
2019-07-24 21:48:14 +00:00
Guanzhong Chen 5204f7611f [WebAssembly] Compute and export TLS block alignment
Summary:
Add immutable WASM global `__tls_align` which stores the alignment
requirements of the TLS segment.

Add `__builtin_wasm_tls_align()` intrinsic to get this alignment in Clang.

The expected usage has now changed to:

    __wasm_init_tls(memalign(__builtin_wasm_tls_align(),
                             __builtin_wasm_tls_size()));

Reviewers: tlively, aheejin, sbc100, sunfish, alexcrichton

Reviewed By: tlively

Subscribers: dschuff, jgravelle-google, hiraditya, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D65028

llvm-svn: 366624
2019-07-19 23:34:16 +00:00
Thomas Lively 6a6f28f7b7 [WebAssembly] Use passive segments by default when memory is shared
Summary:
This change makes it so that passing --shared-memory is all a user
needs to do to get proper multithreaded code. This default can still
be explicitly overridden for any reason using --passive-segments and
--active-segments.

Reviewers: sbc100, quantum

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64950

llvm-svn: 366504
2019-07-18 21:50:24 +00:00
Guanzhong Chen 21aafc2e0c [WebAssembly] fix bug in finding .tdata segment
Summary: Fix bug in `wasm-ld`'s `Writer::createInitTLSFunction` that only finds `.tdata` if it's the first section.

Reviewers: tlively, aheejin, sbc100

Reviewed By: sbc100

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64947

llvm-svn: 366500
2019-07-18 21:18:24 +00:00
Sam Clegg accad76c14 [lld][WebAssembly] Fix handling of comdat functions in init array.
When hidden symbols are discarded by comdat rules we still want to
create a local defined symbol, otherwise `Symbol::isDiscarded()` relies
on begin able to check `getChunk->discarded`.

This is a followup on rL362769. The comdat.ll test was previously GC'ing
the `__wasm_call_ctors` functions so `do_init` was not actually being
included in the link.  Once that function was included in triggered the
crash bug that this change addresses.

Fixes: https://github.com/emscripten-core/emscripten/issues/8981

Differential Revision: https://reviews.llvm.org/D64872

llvm-svn: 366358
2019-07-17 18:43:36 +00:00
Guanzhong Chen 42bba4b852 [WebAssembly] Implement thread-local storage (local-exec model)
Summary:
Thread local variables are placed inside a `.tdata` segment. Their symbols are
offsets from the start of the segment. The address of a thread local variable
is computed as `__tls_base` + the offset from the start of the segment.

`.tdata` segment is a passive segment and `memory.init` is used once per thread
to initialize the thread local storage.

`__tls_base` is a wasm global. Since each thread has its own wasm instance,
it is effectively thread local. Currently, `__tls_base` must be initialized
at thread startup, and so cannot be used with dynamic libraries.

`__tls_base` is to be initialized with a new linker-synthesized function,
`__wasm_init_tls`, which takes as an argument a block of memory to use as the
storage for thread locals. It then initializes the block of memory and sets
`__tls_base`. As `__wasm_init_tls` will handle the memory initialization,
the memory does not have to be zeroed.

To help allocating memory for thread-local storage, a new compiler intrinsic
is introduced: `__builtin_wasm_tls_size()`. This instrinsic function returns
the size of the thread-local storage for the current function.

The expected usage is to run something like the following upon thread startup:

    __wasm_init_tls(malloc(__builtin_wasm_tls_size()));

Reviewers: tlively, aheejin, kripken, sbc100

Subscribers: dschuff, jgravelle-google, hiraditya, sunfish, jfb, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D64537

llvm-svn: 366272
2019-07-16 22:00:45 +00:00
Thomas Lively 26a6b95da9 [WebAssembly] i32.const operands should be signed
Summary:
This was causing large addresses to be emitted as negative numbers,
which rightfully caused crashes in binaryen.

Reviewers: aheejin, dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64612

llvm-svn: 365930
2019-07-12 17:55:07 +00:00
Sam Clegg fd11ce32bb [WebAssembly] Import __stack_pointer when building -pie binaries
The -pie binary doesn't know that layout ahead of time so needs to
import the stack pointer from the embedder, just like we do already
for shared libraries.

This change is needed in order to address:
https://github.com/emscripten-core/emscripten/issues/8915

Differential Revision: https://reviews.llvm.org/D64516

llvm-svn: 365771
2019-07-11 13:13:25 +00:00
Sam Clegg 9abe8c4805 [lld][WebAssembly] Report undefined symbols during scanRelocations
This puts handling of undefined symbols in a single location.  Its
also more in line with the ELF backend which only reports undefined
symbols based on relocations.

One side effect is that we no longer report undefined symbols that are
only referenced in GC'd sections.

This also fixes a crash reported in the emscripten toolchain:
https://github.com/emscripten-core/emscripten/issues/8930.

Differential Revision: https://reviews.llvm.org/D64280

llvm-svn: 365553
2019-07-09 20:45:20 +00:00