Commit Graph

44 Commits

Author SHA1 Message Date
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 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
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
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
Benjamin Kramer adcd026838 Make llvm::StringRef to std::string conversions explicit.
This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.

This is mostly mechanical from a custom clang-tidy check, with a lot of
manual fixups. It uncovers a lot of minor inefficiencies.

This doesn't actually modify StringRef yet, I'll do that in a follow-up.
2020-01-28 23:25:25 +01:00
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
Fangrui Song 33c59abf5c [WebAssembly] Wrap definitions in namespace lld { namespace wasm {. NFC
Similar to D68323, but for wasm.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D68759

llvm-svn: 374279
2019-10-10 05:25:39 +00:00
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
Rui Ueyama 7e296adec7 Make functions and member variables distinguishable even after the name style change. NFC.
llvm-svn: 365605
2019-07-10 09:10:01 +00:00
Bill Wendling 858e35160e Add parentheses to silence warnings.
llvm-svn: 365397
2019-07-08 22:05:02 +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
Thomas Lively b98025a2f7 [WebAssembly] make wasm-ld --verbose show data section startVA and name
Summary:
Make `wasm-ld --verbose` show data section start virtual address and name
as well, instead of just showing the size. This makes it much easier to
track which global variable is in which address when used in conjunction
with `--no-merge-data-sections`.

Patch by Guanzhong Chen

Reviewers: tlively, aheejin, sbc100, ruiu

Reviewed By: sbc100, ruiu

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62834

llvm-svn: 362548
2019-06-04 21:13:41 +00:00
Sam Clegg 8fcf012693 [WebAssembly] Refactor synthetic sections and relocation processing. NFC.
Major refactor to better match the structure of the ELF linker.

- Split out relocation processing into scanRelocations
- Split out synthetic sections into their own classes.

Differential Revision: https://reviews.llvm.org/D61811

llvm-svn: 361233
2019-05-21 09:13:09 +00:00
Sam Clegg d029bf0f8c [WebAssembly] Move code and data section generation to finalizeContent. NFC.
Previously these sections were being generated during their
constructors.  This moves the work to finalizeContent, and also does
the same for the relocation sections because their contents depends
on the final layout too.

This change is part of a larger refactor to how we deal with synthetic
sections: https://reviews.llvm.org/D61811

Differential Revision: https://reviews.llvm.org/D61971

llvm-svn: 360941
2019-05-16 21:36:06 +00:00
Thomas Lively 84771e2d21 [WebAssembly] Emit the DataCount section when bulk memory is enabled
Summary:
The DataCount section is necessary for the bulk memory operations
memory.init and data.drop to validate, but it is not recognized by
engines that do not support bulk memory, so emit the section only if
bulk-memory is enabled.

Reviewers: aheejin, dschuff, sbc100

Subscribers: jgravelle-google, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60637

llvm-svn: 358798
2019-04-19 23:40:36 +00:00
Rui Ueyama 5081e41bda Fix a crash bug caused by a nested call of parallelForEach.
parallelForEach is not reentrant. We use parallelForEach to call
each section's writeTo(), so calling the same function within writeTo()
is not safe.

Fixes https://bugs.llvm.org/show_bug.cgi?id=41508

Differential Revision: https://reviews.llvm.org/D60757

llvm-svn: 358547
2019-04-17 02:12:47 +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
Thomas Lively 25ff893712 [WebAssembly] Instruction renaming
Summary: Associated with D56338.

Reviewers: aheejin, aardappel

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

Differential Revision: https://reviews.llvm.org/D56339

llvm-svn: 350610
2019-01-08 06:25:55 +00:00
Heejin Ahn e915a71f18 [WebAssembly] Add support for the event section
Summary:
This adds support for the 'event section' specified in the exception
handling proposal.

Wasm exception handling binary model spec:
https://github.com/WebAssembly/exception-handling/blob/master/proposals/Exceptions.md#changes-to-the-binary-model

Reviewers: sbc100, ruiu

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

Differential Revision: https://reviews.llvm.org/D54875

llvm-svn: 348703
2018-12-08 06:17:43 +00:00
Sam Clegg 2dad4e2c6d [WebAssembly] Import the stack pointer when building shared libraries
Differential Revision: https://reviews.llvm.org/D54558

llvm-svn: 346974
2018-11-15 18:15:54 +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
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 d177ab2a5f [WebAssembly] Add support for debug (DWARF) sections
Specifically add support for custom sections that contain
relocations, and for the two new relocation types needed
by DWARF sections.

See: https://reviews.llvm.org/D44184

Patch by Yury Delendik!

Differential Revision: https://reviews.llvm.org/D44184

llvm-svn: 331566
2018-05-04 23:14:42 +00:00
Sam Clegg 80ba43872e [WebAssembly] Add support for custom sections
Copy user-defined custom sections into the output, concatenating
sections with the same name.

Differential Revision: https://reviews.llvm.org/D45340

llvm-svn: 329717
2018-04-10 16:12:49 +00:00
Rui Ueyama ac95bb1d52 [WebAssembly] Remove another trivial accessor.
Differential Revision: https://reviews.llvm.org/D43725

llvm-svn: 329336
2018-04-05 19:37:31 +00:00
Nicholas Wilson dbd90bf8d1 [WebAssembly] Run clang-format. NFC
llvm-svn: 326896
2018-03-07 13:28:16 +00:00
Rui Ueyama 22c8f33a9b [WebAssembly] Return a StringRef instead of std::string from getSectionName(). NFC.
Differential Revision: https://reviews.llvm.org/D43854

llvm-svn: 326337
2018-02-28 17:33:04 +00:00
Rui Ueyama 4a1b2bbc88 [WebAssembly] Do not use inheritance to define SubSection.
SubSection inherited from SyntheticSection, and SyntheticSection inherits
from OutputSection, so SubSection was an OutputSection. But that's wrong
because SubSection is not actually a WebAssembly output section.
It shares some functionalities with OutputSection, but overall it's very
different.

This patch removes that inheritance.

Differential Revision: https://reviews.llvm.org/D43719

llvm-svn: 326286
2018-02-28 00:52:42 +00:00
Rui Ueyama 319eb8b3c3 [WebAssembly] Remove redundant local variables.
Differential Revision: https://reviews.llvm.org/D43709

llvm-svn: 326280
2018-02-28 00:31:16 +00:00
Sam Clegg 3141ddc58d Consistent (non) use of empty lines in include blocks
The profailing style in lld seem to be to not include such empty lines.
Clang-tidy/clang-format seem to handle this just fine.

Differential Revision: https://reviews.llvm.org/D43528

llvm-svn: 325629
2018-02-20 21:53:18 +00:00
Rui Ueyama bf450d905d Do not create a temporary data structure for relocations.
This patch removes `OutRelocations` vector from the InputChunk and
directly consume `Relocations` vector instead. This should make the linker
faster because we don't create a temporary data structure, and it matches
the lld's design principle that we don't create temporary data structures
for object files but instead directly consume mmap'ed data whenever possible.

Differential Revision: https://reviews.llvm.org/D43491

llvm-svn: 325549
2018-02-20 04:26:26 +00:00
Rui Ueyama 1184253891 Refactor wasm/WriterUtil.{cpp,h}.
Summary:
 - Makes code more in line with LLVM style (e.g. const char * -> StringRef)
 - Do not use formatv since we can construct message just by `+`
 - Replace some odd types such as `const StringRef` with more common type
 - Do not use default arguments if they are not necessary

Reviewers: sbc100

Subscribers: jfb, aheejin, llvm-commits, sunfish

Differential Revision: https://reviews.llvm.org/D43403

llvm-svn: 325383
2018-02-16 20:38:00 +00:00
Sam Clegg d96d93576b [WebAssembly] Move relocation handling InputChunks.cpp
Teach each input chunk how to write itself and apply its
own relocations.

Differential Revision: https://reviews.llvm.org/D41891

llvm-svn: 322212
2018-01-10 19:22:42 +00:00
Sam Clegg 5fa274bea4 [WebAssembly] Add InputChunk as common base class for InputSegment and InputFunction. NFC.
Differential Revision: https://reviews.llvm.org/D41419

llvm-svn: 322148
2018-01-10 01:13:34 +00:00
Sam Clegg 8d146bbc0c [WebAssembly] Output functions individually
The code section is now written out one function
at a time rather than all the functions in a given
objects being serialized at once.

This change lays the groundwork for supporting
--gc-sections.

Differential Revision: https://reviews.llvm.org/D41315

llvm-svn: 322138
2018-01-09 23:56:44 +00:00
Sam Clegg 87e61923a4 [WebAssembly] Write out undefined symbol addresses as zero
The addresses of undefined symbols that make it into the final
executable (i.e. weak references to non-existent symbols) should
resolve to zero.

Also, make sure to not include function in the indirect function
table if they are not included in the output.

Differential Revision: https://reviews.llvm.org/D41839

llvm-svn: 322045
2018-01-08 23:39:11 +00:00
Sam Clegg ab2ac29066 [WebAssembly] Improve toString(OutputSection). NFC.
llvm-svn: 321146
2017-12-20 05:14:48 +00:00
Sam Clegg 5e8cba9e39 [WebAssembly] Apply data relocations in parallel. NFC.
Store data relocations with their respective segment.
This allows relocations to be applied as each segment
is written (and therefore in parallel).

Differential Revision: https://reviews.llvm.org/D41410

llvm-svn: 321105
2017-12-19 20:45:15 +00:00
Sam Clegg 0d0dd39159 [WebAssembly] Add support for writing out init functions in linking section
This change add support for init functions in the linking
section, but only in -r/--relocatable mode.

Differential Revision: https://reviews.llvm.org/D41375

llvm-svn: 321088
2017-12-19 17:09:45 +00:00
Sam Clegg ca16b73692 [WebAssebmly] Fix the single clang-format issue in `wasm` directory
llvm-svn: 321020
2017-12-18 20:20:24 +00:00
Sam Clegg 0fb6faa0be Prefer `ArrayRef` over `const std::vector&`
Differential Revision: https://reviews.llvm.org/D40993

llvm-svn: 320125
2017-12-08 01:09:21 +00:00
Sam Clegg 74fe0ba105 [WebAssembly] Fix symbol exports under -r/--relocatable
This change cleans up the way wasm exports and globals
are generated, particualrly for -r/--relocatable where
globals need to be created and exported in order for
output relocations which reference them.

Remove the need for a per file GlobalIndexOffset and
instead set the output index for each symbol directly.
This simplifies the code in several places.

Differential Revision: https://reviews.llvm.org/D40859

llvm-svn: 320001
2017-12-07 01:51:24 +00:00
Rui Ueyama 2017d52b54 Move Memory.{h,cpp} to Common.
Differential Revision: https://reviews.llvm.org/D40571

llvm-svn: 319221
2017-11-28 20:39:17 +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