Commit Graph

15 Commits

Author SHA1 Message Date
Thomas Lively 3f34e1b883 [WebAssembly] Merge used feature sets, update atomics linkage policy
Summary:
It does not currently make sense to use WebAssembly features in some functions
but not others, so this CL adds an IR pass that takes the union of all used
feature sets and applies it to each function in the module. This allows us to
prevent atomics from being lowered away if some function has opted in to using
them. When atomics is not enabled anywhere, we detect whether there exists any
atomic operations or thread local storage that would be stripped and disallow
linking with objects that contain atomics if and only if atomics or tls are
stripped. When atomics is enabled, mark it as used but do not require it of
other objects in the link. These changes allow libraries that do not use atomics
to be built once and linked into both single-threaded and multithreaded
binaries.

Reviewers: aheejin, sbc100, dschuff

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59625

llvm-svn: 357226
2019-03-29 00:14:01 +00:00
Thomas Lively f6f4f84378 [WebAssembly] Target features section
Summary:
Implements a new target features section in assembly and object files
that records what features are used, required, and disallowed in
WebAssembly objects. The linker uses this information to ensure that
all objects participating in a link are feature-compatible and records
the set of used features in the output binary for use by optimizers
and other tools later in the toolchain.

The "atomics" feature is always required or disallowed to prevent
linking code with stripped atomics into multithreaded binaries. Other
features are marked used if they are enabled globally or on any
function in a module.

Future CLs will add linker flags for ignoring feature compatibility
checks and for specifying the set of allowed features, implement using
the presence of the "atomics" feature to control the type of memory
and segments in the linked binary, and add front-end flags for
relaxing the linkage policy for atomics.

Reviewers: aheejin, sbc100, dschuff

Subscribers: jgravelle-google, hiraditya, sunfish, mgrang, jfb, jdoerfert, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59173

llvm-svn: 356610
2019-03-20 20:26:45 +00:00
Heejin Ahn 3c20b34d24 [WebAssembly] Remove trailing whitespaces in tests (NFC)
Reviewers: sbc100

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D58955

llvm-svn: 355472
2019-03-06 02:00:22 +00:00
Sam Clegg 56c587adfd [WebAssembly] Store section alignment as a power of 2
This change bumps for version number of the wasm object file
metadata.

See https://github.com/WebAssembly/tool-conventions/pull/92

Differential Revision: https://reviews.llvm.org/D56758

llvm-svn: 351285
2019-01-16 01:34:48 +00:00
Sam Clegg a5908009cd [WebAsembly] Update default triple in test files to wasm32-unknown-unkown.
Summary: The final -wasm component has been the default for some time now.

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

Differential Revision: https://reviews.llvm.org/D46342

llvm-svn: 332007
2018-05-10 17:49:11 +00:00
Sam Clegg 6bb5a41f99 [WebAssembly] Add version to object file metadata
Summary: See https://github.com/WebAssembly/tool-conventions/issues/54

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

Differential Revision: https://reviews.llvm.org/D46069

llvm-svn: 330969
2018-04-26 18:15:32 +00:00
Sam Clegg 86b4a09a99 [WebAssembly] Remove DataSize from linking metadata section
Neither the linker nor the runtime need this information
anymore.  We were originally using this to model BSS size
but the plan is now to use the segment metadata to allow
for BSS segments.

Differential Revision: https://reviews.llvm.org/D41366

llvm-svn: 326267
2018-02-27 23:57:37 +00:00
Sam Clegg 6c899ba6de [WebAssembly] Add first claass symbol table to wasm objects
This is combination of two patches by Nicholas Wilson:
  1. https://reviews.llvm.org/D41954
  2. https://reviews.llvm.org/D42495

Along with a few local modifications:
- One change I made was to add the UNDEFINED bit to the binary format
  to avoid the extra byte used when writing data symbols.  Although this
  bit is redundant for other symbols types (i.e. undefined can be
  implied if a function or global is a wasm import)
- I prefer to be explicit and consistent and not have derived flags.
- Some field renaming.
- Some reverting of unrelated minor changes.
- No test output differences.

Differential Revision: https://reviews.llvm.org/D43147

llvm-svn: 325860
2018-02-23 05:08:34 +00:00
Sam Clegg 0fc5599f52 [WebAssembly] Use bitfield types in wasm YAML representation
Differential Revision: https://reviews.llvm.org/D41202

llvm-svn: 320642
2017-12-13 22:02:25 +00:00
Sam Clegg 223e2d4f04 [WebAssembly] Update MC tests now that hidden attr is supported
Summary:
Support was added in rL319488 but these tests were not
updated.

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

Differential Revision: https://reviews.llvm.org/D40693

llvm-svn: 319510
2017-12-01 01:18:47 +00:00
Sam Clegg 63ebb81386 [WebAssembly] Allow each data segment to specify its own alignment
Also, add a flags field as we will almost certainly
be needing that soon too.

Differential Revision: https://reviews.llvm.org/D38296

llvm-svn: 314534
2017-09-29 16:50:08 +00:00
Sam Clegg d95ed959d8 Reland "[WebAssembly] Add support for naming wasm data segments"
Add adds support for naming data segments.  This is useful
useful linkers so that they can merge similar sections.

Differential Revision: https://reviews.llvm.org/D37886

llvm-svn: 313795
2017-09-20 19:03:35 +00:00
Mike Edwards b487bf45f0 Reverting due to Green Dragon bot failure.
http://green.lab.llvm.org/green/job/clang-stage1-cmake-RA-incremental/42594/

llvm-svn: 313706
2017-09-20 01:21:02 +00:00
Sam Clegg b292c25966 [WebAssembly] Add support for naming wasm data segments
Add adds support for naming data segments.  This is useful
useful linkers so that they can merge similar sections.

Differential Revision: https://reviews.llvm.org/D37886

llvm-svn: 313692
2017-09-19 23:00:57 +00:00
Sam Clegg b03c2b4b09 [WebAssembly] Use the correct size for MCFillFragment
Summary: When implementing MCFillFragment, use the size of the fragment,
rather than the size of the section.

Patch by Dan Gohman

Differential Revision: https://reviews.llvm.org/D35090

llvm-svn: 307565
2017-07-10 18:36:34 +00:00