Commit Graph

37 Commits

Author SHA1 Message Date
Rui Ueyama 136d27ab4d [Coding style change][lld] Rename variables for non-ELF ports
This patch does the same thing as r365595 to other subdirectories,
which completes the naming style change for the entire lld directory.

With this, the naming style conversion is complete for lld.

Differential Revision: https://reviews.llvm.org/D64473

llvm-svn: 365730
2019-07-11 05:40:30 +00:00
Thomas Lively 6004d9a13d [WebAssembly] Add option to emit passive segments
Summary:
Adds `--passive-segments` and `--active-segments` flags to control
what kind of segments are emitted. For now the default is always
to emit active segments so this is not a breaking change, but in
the future the default will be changed to passive segments when
shared memory is requested and active segments otherwise. When
passive segments are emitted, corresponding memory.init and
data.drop instructions are emitted in a `__wasm_init_memory`
function that is automatically called at the beginning of
`__wasm_call_ctors`.

Reviewers: sbc100, aheejin, dschuff

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59343

llvm-svn: 365088
2019-07-03 22:04:54 +00:00
Sam Clegg 7d4ec5af6c [WebAssembly] Don't export __data_end and __heap_base by default.
These can still be exported via --export if needed.

Differential Revision: https://reviews.llvm.org/D62744

llvm-svn: 362276
2019-05-31 22:51:59 +00:00
Sam Clegg 35be7ff80c [WebAssembly] Add support for -emit-relocs
This can be useful for post-link tools and for testing.  Sometimes
it can be useful to produces a regular executable but with relocations
preserved.

Differential Revision: https://reviews.llvm.org/D62378

llvm-svn: 361635
2019-05-24 13:28:27 +00:00
Sam Clegg a1282a39ba [WebAssembly] Handle command line options consistently with the ELF backend.
Differential Revision: https://reviews.llvm.org/D61645

llvm-svn: 360266
2019-05-08 16:20:05 +00:00
Thomas Lively 82de51a3ae Reland "[WebAssembly] Add linker options to control feature checking"
Do not pipe binary data between processes in lit tests this time,
since it turns out that can break on Windows.

This reverts commit 84c8652fc3.

llvm-svn: 356975
2019-03-26 04:11:05 +00:00
Thomas Lively 84c8652fc3 Revert "[WebAssembly] Add linker options to control feature checking"
This reverts commit 5991328c96.

llvm-svn: 356932
2019-03-25 18:10:26 +00:00
Thomas Lively 5991328c96 [WebAssembly] Add linker options to control feature checking
Summary:
Adds --check-features and --no-check-features. The default for now is
to enable the checking, but this might change in the future.

Also adds --features=foo,bar for precisely controlling the features
used in the output binary.

Depends on D59173.

Reviewers: sbc100, aheejin

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59274

llvm-svn: 356805
2019-03-22 20:43:06 +00:00
Sam Clegg 1f3f774f10 [WebAssembly] Implement --trace and --trace-symbol
Differential Revision: https://reviews.llvm.org/D57725

llvm-svn: 353264
2019-02-06 02:35:18 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
Sam Clegg bfb75348e2 [WebAssembly] Initial support for shared objects (-shared)
Based on the initial spec proposal:
https://github.com/WebAssembly/tool-conventions/blob/master/DynamicLinking.md

The llvm/codegen side of this is still missing but I believe this change is
still worth landing as an incremental step

Differential Revision: https://reviews.llvm.org/D54249

llvm-svn: 346918
2018-11-15 00:37:21 +00:00
Derek Schuff 3bea8bcae5 [WebAssembly] Support creation and import of shared memories
Used for WebAssembly threads proposal. Add a flag --shared-memory
which sets the IS_SHARED bit in WasmLimits

Differential Revision: https://reviews.llvm.org/D54130

llvm-svn: 346248
2018-11-06 17:59:32 +00:00
Sam Clegg 305b0343ce [WebAssembly] Add --[no]-export-dynamic to replace --export-default
In a very recent change I introduced a --no-export-default flag
but after conferring with others it seems that this feature already
exists in gnu GNU ld and lld in the form the --export-dynamic flag
which is off by default.

This change replaces export-default with export-dynamic and also
changes the default to match the traditional linker behaviour.

Now, by default, only the entry point is exported.  If other symbols
are required by the embedder then --export-dynamic or --export can
be used to export all visibility hidden symbols or individual
symbols respectively.

This change touches a lot of tests that were relying on symbols
being exported by default.  I imagine it will also effect many
users but do think the change is worth it match of the traditional
behaviour and flag names.

Differential Revision: https://reviews.llvm.org/D52587

llvm-svn: 343265
2018-09-27 21:06:25 +00:00
Sam Clegg 4aad12ce0b [WebAssembly] Update Config member to match command line option
Subscribers: dschuff, jgravelle-google, aheejin, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D50976

llvm-svn: 343157
2018-09-27 00:46:54 +00:00
Sam Clegg 4e62418b25 [WebAssembly] Add --export-default/--no-export-default options
These option control weather or not symbols marked as visibility
default are exported in the output binary.

By default this is true, but emscripten prefers to control the
exported symbol list explicitly at link time and ignore the
symbol attributes.

Differential Revision: https://reviews.llvm.org/D52003

llvm-svn: 343034
2018-09-25 21:50:15 +00:00
Sam Clegg 177b458c8a [WebAssembly] Add --export-all flag
This causes all symbols to be exported in the final wasm binary
even if they were not compiled with default visibility.

This feature is useful for the emscripten toolchain that has a
corresponding EXPORT_ALL feature which allows the JS code to
interact with all C function.

Differential Revision: https://reviews.llvm.org/D47806

llvm-svn: 334157
2018-06-07 01:27:07 +00:00
Sam Clegg c729c1b47d [WebAssembly] Initial support for LTO
Differential Revision: https://reviews.llvm.org/D47162

llvm-svn: 333570
2018-05-30 18:07:52 +00:00
Sam Clegg fb983cda8a [WebAssembly] Add option to remove LEB padding at relocate sites
This change adds the ability for lld to remove LEB padding from
code section. This effectively shrinks the size of the resulting
binary in proportion to the number of code relocations.

Since there will be a performance cost this is currently only active for
-O1 and above. Some toolchains may instead want to perform this
compression as a post linker step (for example running a binary through
binaryen will automatically compress these values).

I imagine we might want to make this the default in the future.

Differential Revision: https://reviews.llvm.org/D46416

llvm-svn: 332783
2018-05-18 23:28:05 +00:00
Sam Clegg 668447677a [WebAssembly] Add a flag to control merging data segments
Merging data segments produces smaller code sizes because each segment
has some boilerplate. Therefore, merging data segments is generally the
right approach, especially with wasm where binaries are typically
delivered over the network.

However, when analyzing wasm binaries, it can be helpful to get a
conservative picture of which functions are using which data
segments[0]. Perhaps there is a large data segment that you didn't
expect to be included in the wasm, introduced by some library you're
using, and you'd like to know which library it was. In this scenario,
merging data segments only makes the analysis worse.

Alternatively, perhaps you will remove some dead functions by-hand[1]
that can't be statically proven dead by the compiler or lld, and
removing these functions might make some data garbage collect-able, and
you'd like to run `--gc-sections` again so that this now-unused data can
be collected. If the segments were originally merged, then a single use
of the merged data segment will entrench all of the data.

[0] https://github.com/rustwasm/twiggy
[1] https://github.com/fitzgen/wasm-snip

Patch by Nick Fitzgerald!

Differential Revision: https://reviews.llvm.org/D46417

llvm-svn: 332013
2018-05-10 18:23:51 +00:00
Sam Clegg 752494bfe3 [WebAssembly] Check function signatures by default
But only produce a warning (for now) unless --fatal-warnings
is passed.

Differential Revision: https://reviews.llvm.org/D46484

llvm-svn: 331574
2018-05-05 01:23:07 +00:00
Sam Clegg a0f095ebd7 [WebAssembly] Add --stack-first option which places the shadow stack at start of linear memory
Fixes https://bugs.llvm.org/show_bug.cgi?id=37181

Differential Revision: https://reviews.llvm.org/D46141

llvm-svn: 331467
2018-05-03 17:21:53 +00:00
Nicholas Wilson fc90b30dc2 [WebAssembly] Name Config members after commandline argument. NFC
This addresses a late review comment from D44427/rLLD328643

llvm-svn: 328700
2018-03-28 12:53:29 +00:00
Nicholas Wilson 874eedd779 [WebAssembly] Add export/import for function pointer table
This enables callback-style programming where the JavaScript environment
can call back into the Wasm environment using a function pointer
received from the module.

Differential Revision: https://reviews.llvm.org/D44427

llvm-svn: 328643
2018-03-27 17:38:51 +00:00
Rui Ueyama 0931e957ff [WebAssembly] Remove unused forward declaration.
llvm-svn: 326411
2018-03-01 02:37:26 +00:00
Sam Clegg f0d433d0c6 [WebAssembly] Refactor linker-generated symbols. NFC.
Group all synthetic symbols in the in single struct to match
the ELF linker.

This change is part of a larger change to add more linker
symbols such as `_end` and `_edata`.

Differential Revision: https://reviews.llvm.org/D42866

llvm-svn: 324157
2018-02-02 22:59:56 +00:00
Sam Clegg 0362633fd2 [WebAssembly] Add support for --gc-sections
In this initial version we only GC symbols with `hidden` visibility since
other symbols we export to the embedder.

We could potentially modify this the future and only use symbols
explicitly passed via `--export` as GC roots.

This version of the code only does GC of data and code. GC for the
types section is coming soon.

Differential Revision: https://reviews.llvm.org/D42511

llvm-svn: 323842
2018-01-31 01:45:47 +00:00
Sam Clegg b5885118f4 [WebAssembly] Remove unneeded include. NFC.
llvm-svn: 323620
2018-01-28 19:33:00 +00:00
Sam Clegg ff2b12216b [WebAssembly] Remove --emit-relocs
This was added to mimic ELF, but maintaining it has cost
and we currently don't have any use for it outside of the
test code.

Differential Revision: https://reviews.llvm.org/D42324

llvm-svn: 323154
2018-01-22 21:55:43 +00:00
Sam Clegg 51bcdc2d49 [WebAssembly] Define __heap_base global
This is an immutable exported global representing
the start of the heap area.  It is a page aligned.

Differential Revision: https://reviews.llvm.org/D42030

llvm-svn: 322609
2018-01-17 01:34:31 +00:00
Sam Clegg 5068685678 [WebAssembly] Create synthetic __wasm_call_ctors function
This change create a new synthetic function in the final
output binary which calls the static constructors in sequence.

See: https://github.com/WebAssembly/tool-conventions/issues/25

Differential Revision: https://reviews.llvm.org/D41893

llvm-svn: 322388
2018-01-12 18:35:13 +00:00
Sam Clegg 80cfdd6b56 [WebAssembly] Remove used variable
llvm-svn: 320007
2017-12-07 03:51:37 +00:00
Sam Clegg 4eedcfc946 [WebAssembly] Improve support linker synthetic symbols
This is part of larger change to add synthetic symbols
for section start/end points and init/fini_array:
  https://reviews.llvm.org/D40760

Allows synthetic global symbols to have an explicitly set
virtual address.

Differential Revision: https://reviews.llvm.org/D40843

llvm-svn: 319813
2017-12-05 19:05:45 +00:00
Sam Clegg 3b4a475c37 [WebAssembly] Remove used --sysroot option
Differential Revision: https://reviews.llvm.org/D40771

llvm-svn: 319805
2017-12-05 18:13:45 +00:00
Sam Clegg b862159683 [WebAssembly] Allow function signature checking at link time
This change allows checking of function signatures but
does not yes enable it by default.  In this mode, linking
two objects that were compiled with a different signatures
for the same function will produce a link error.

New options for enabling and disabling this feature have been
added: (--check-signatures/--no-check-signatures).

Differential Revision: https://reviews.llvm.org/D40371

llvm-svn: 319396
2017-11-30 01:40:08 +00:00
Rui Ueyama 7d5a13799a Use llvm::StringSet instead of std::set.
std::set is pretty slow. We generally prefer llvm::StringSet if we don't
need an sorted set.

Differential Revision: https://reviews.llvm.org/D40579

llvm-svn: 319371
2017-11-29 22:21:37 +00:00
Sam Clegg f95826dccd [WebAssembly] Remove initializers from Config.h
These should get initialized in by Driver.cpp based on
command line options.

Also, sort entries.

Differential Revision: https://reviews.llvm.org/D40570

llvm-svn: 319219
2017-11-28 20:27:21 +00:00
Sam Clegg c94d393ad5 [WebAssembly] Initial wasm linker implementation
This linker backend is still a work in progress but is
enough to link simple programs including linking against
library archives.

Differential Revision: https://reviews.llvm.org/D34851

llvm-svn: 318539
2017-11-17 18:14:09 +00:00