Commit Graph

448 Commits

Author SHA1 Message Date
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
Wei Mi 21a4710c67 [ThinLTO] Pass CodeGenOpts like UnrollLoops/VectorizeLoop/VectorizeSLP
down to pass builder in ltobackend.

Currently CodeGenOpts like UnrollLoops/VectorizeLoop/VectorizeSLP in clang
are not passed down to pass builder in ltobackend when new pass manager is
used. This is inconsistent with the behavior when new pass manager is used
and thinlto is not used. Such inconsistency causes slp vectorization pass
not being enabled in ltobackend for O3 + thinlto right now. This patch
fixes that.

Differential Revision: https://reviews.llvm.org/D72386
2020-01-09 21:13:11 -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 681b1be774 [lld] Fix -Wrange-loop-analysis warnings
One instance looks like a false positive:

lld/ELF/Relocations.cpp:1622:14: note: use reference type 'const std::pair<ThunkSection *, uint32_t> &' (aka 'cons
t pair<lld:🧝:ThunkSection *, unsigned int> &') to prevent copying
        for (const std::pair<ThunkSection *, uint32_t> ts : isd->thunkSections)

It is not changed in this commit.
2020-01-01 15:41:20 -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
James Y Knight d3fec7fb45 LLD: Don't use the stderrOS stream in link before it's reassigned.
Remove the lld::enableColors function, as it just obscures which
stream it's affecting, and replace with explicit calls to the stream's
enable_colors.

Also, assign the stderrOS and stdoutOS globals first in link function,
just to ensure nothing might use them.

(Either change individually fixes the issue of using the old
stream, but both together seems best.)

Follow-up to b11386f9be.

Differential Revision: https://reviews.llvm.org/D70492
2019-11-21 10:55:03 -05:00
Rui Ueyama b11386f9be Make it possible to redirect not only errs() but also outs()
This change is for those who use lld as a library. Context:
https://reviews.llvm.org/D70287

This patch adds a new parmeter to lld::*::link() so that we can pass
an raw_ostream object representing stdout. Previously, lld::*::link()
took only an stderr object.

Justification for making stdoutOS and stderrOS mandatory: I wanted to
make link() functions to take stdout and stderr in that order.
However, if we change the function signature from

  bool link(ArrayRef<const char *> args, bool canExitEarly,
            raw_ostream &stderrOS = llvm::errs());

to

  bool link(ArrayRef<const char *> args, bool canExitEarly,
            raw_ostream &stdoutOS = llvm::outs(),
            raw_ostream &stderrOS = llvm::errs());

, then the meaning of existing code that passes stderrOS silently
changes (stderrOS would be interpreted as stdoutOS). So, I chose to
make existing code not to compile, so that developers can fix their
code.

Differential Revision: https://reviews.llvm.org/D70292
2019-11-18 11:18:06 +09:00
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
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
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
Sam Clegg ad2e12a3d9 [lld][WebAssembly] Refactor markLive.cpp. NFC
This pattern matches the ELF implementation add if also useful as
part of a planned change where running `mark` more than once is needed.

Differential Revision: https://reviews.llvm.org/D68749

llvm-svn: 374275
2019-10-10 03:23:06 +00:00
Martin Storsjo 5ebab1f8f9 [LLD] Simplify the demangleItanium function. NFC.
Instead of returning an optional, just return the input string if
demangling fails, as that's what all callers use anyway.

Differential Revision: https://reviews.llvm.org/D68015

llvm-svn: 373077
2019-09-27 12:24:18 +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 0c3d4cfbad [WebAssembly][NFC] Remove unnecessary braces
llvm-svn: 372358
2019-09-19 21:51:52 +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
Sam Clegg e40ef12bfa [lld][WebAssembly] Fix use after free of archive path
This was fixed in the ELF backend in https://reviews.llvm.org/D34554.

Differential Revision: https://reviews.llvm.org/D67676

llvm-svn: 372266
2019-09-18 21:51:03 +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
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
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 1a1df72a43 [lld][WebAssembly] Store table base in config rather than passing it around. NFC.
I've got another change that makes more use of this value in other
places.

Differential Revision: https://reviews.llvm.org/D66777

llvm-svn: 370010
2019-08-27 04:19:34 +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
Jonas Devlieghere 6ba7992031 [LLD] Migrate llvm::make_unique to std::make_unique
Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.

Differential revision: https://reviews.llvm.org/D66259

llvm-svn: 368936
2019-08-14 22:28:17 +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 dbfea28219 [lld][WebAssembly] Don't create optional symbols when outputing an object file
Summary: This was a bug in rL368310.  I'm working on a test case now.

Differential Revision: https://reviews.llvm.org/D65985

llvm-svn: 368369
2019-08-08 23:56:21 +00:00
Guanzhong Chen c5ccbf52ad [WebAssembly][lld] control __data_end export with config->shared
Summary:
Emscripten expects `__data_end` to show up in PIC code as long as it's not
linked with `--shared`.

Currently, Emscripten breaks with latest LLVM because `__data_end` is controlled
by `config->isPic` instead of `config->shared`.`

Reviewers: tlively, sbc100

Reviewed By: sbc100

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65980

llvm-svn: 368361
2019-08-08 22:40:04 +00:00
Sam Clegg ad1cc145e8 [lld][WebAssembly] Use createGlobalVariable helper function. NFC.
Differential Revision: https://reviews.llvm.org/D65911

llvm-svn: 368325
2019-08-08 18:22:03 +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
Rui Ueyama cac8df1ab9 Re-submit r367649: Improve raw_ostream so that you can "write" colors using operator<<
The original patch broke buildbots, perhaps because it changed the
default setting whether colors are enabled or not.

llvm-svn: 368131
2019-08-07 08:08:17 +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
Rui Ueyama 4d41c332ef Revert r367649: Improve raw_ostream so that you can "write" colors using operator<<
This reverts commit r367649 in an attempt to unbreak Windows bots.

llvm-svn: 367658
2019-08-02 07:22:34 +00:00
Rui Ueyama a52f982f1c Improve raw_ostream so that you can "write" colors using operator<<
1. raw_ostream supports ANSI colors so that you can write messages to
the termina with colors. Previously, in order to change and reset
color, you had to call `changeColor` and `resetColor` functions,
respectively.

So, if you print out "error: " in red, for example, you had to do
something like this:

  OS.changeColor(raw_ostream::RED);
  OS << "error: ";
  OS.resetColor();

With this patch, you can write the same code as follows:

  OS << raw_ostream::RED << "error: " << raw_ostream::RESET;

2. Add a boolean flag to raw_ostream so that you can disable colored
output. If you disable colors, changeColor, operator<<(Color),
resetColor and other color-related functions have no effect.

Most LLVM tools automatically prints out messages using colors, and
you can disable it by passing a flag such as `--disable-colors`.
This new flag makes it easy to write code that works that way.

Differential Revision: https://reviews.llvm.org/D65564

llvm-svn: 367649
2019-08-02 04:48:30 +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
Fangrui Song 33fdf82dda [WebAssembly] Rename variale references in comments after VariableName -> variableName change
llvm-svn: 366192
2019-07-16 08:08:17 +00:00
Heejin Ahn 9f96a58ccc [WebAssembly] Rename except_ref type to exnref
Summary:
We agreed to rename `except_ref` to `exnref` for consistency with other
reference types in
https://github.com/WebAssembly/exception-handling/issues/79. This also
renames WebAssemblyInstrExceptRef.td to WebAssemblyInstrRef.td in order
to use the file for other reference types in future.

Reviewers: dschuff

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64703

llvm-svn: 366145
2019-07-15 22:49:25 +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
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