Commit Graph

159 Commits

Author SHA1 Message Date
Wouter van Oortmerssen 29f8c9f6c2 [WebAssembly] Triple::wasm64 related cleanup
Differential Revision: https://reviews.llvm.org/D83713
2020-07-16 12:01:10 -07:00
Dan Gohman 46a3268312 [WebAssembly] Add warnings for -shared and -pie
The meaning of -shared and -pie are expected to be changed in the
future when Module Linking-style libraries are implemented. Begin
issuing warnings to give people a heads-up that they will be changing.

For compatibility with Emscripten, add a --experimental-pic flag which
disables these warnings.

Differential Revision: https://reviews.llvm.org/D81760
2020-06-25 15:55:46 -07:00
Wouter van Oortmerssen b9a539c010 [WebAssembly] Adding 64-bit versions of __stack_pointer and other globals
We have 6 globals, all of which except for __table_base are 64-bit under wasm64.

Differential Revision: https://reviews.llvm.org/D82130
2020-06-25 15:52:44 -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
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
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
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
Reid Kleckner 213aea4c58 Remove unused Endian.h includes, NFC
Mainly avoids including Host.h everywhere:

$ diff -u <(sort thedeps-before.txt) <(sort thedeps-after.txt) \
    | grep '^[-+] ' | sort | uniq -c | sort -nr
   3141 - /usr/local/google/home/rnk/llvm-project/llvm/include/llvm/Support/Host.h
2020-03-11 15:45:34 -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 bd4812776b [WebAssembly] Use llvm::Optional to store optional symbol attributes. NFC.
The changes the in-memory representation of wasm symbols such that their
optional ImportName and ImportModule use llvm::Optional.

ImportName is set whenever WASM_SYMBOL_EXPLICIT_NAME flag is set.
ImportModule (for imports) is currently always set since it defaults to
"env".

In the future we can possibly extent to binary format distingish
import which have explit module names.

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D74109
2020-02-19 17:25:33 -08:00
Jonas Devlieghere 3e24242a7d [lld] Replace SmallStr.str().str() with std::string conversion operator.
Use the std::string conversion operator introduced in
d7049213d0.
2020-01-29 21:30:21 -08:00
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
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
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
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
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 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 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
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 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 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
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 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
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
Nico Weber a780276301 lld, llvm-dlltool, llvm-lib: Use getAsString() instead of getSpelling() for printing unknown args
Since OPT_UNKNOWN args never have any values and consist only of
spelling (and are never aliased), this doesn't make any difference in
practice, but it's more consistent with Arg's guidance to use
getAsString() for diagnostics, and it matches what clang does.

Also tweak two tests to use an unknown option that contains '=' for
additional coverage while here. (The new tests pass fine with the old
code too though.)

llvm-svn: 365200
2019-07-05 12:31:32 +00:00
Nico Weber cf1a11ded2 Make joined instances of JoinedOrSeparate flags point to the unaliased args, like all other arg types do
This fixes an 8-year-old regression. r105763 made it so that aliases
always refer to the unaliased option – but it missed the "joined" branch
of JoinedOrSeparate flags. (r162231 then made the Args classes
non-virtual, and r169344 moved them from clang to llvm.)

Back then, there was no JoinedOrSeparate flag that was an alias, so it
wasn't observable. Now /U in CLCompatOptions is a JoinedOrSeparate alias
in clang, and warn_slash_u_filename incorrectly used the aliased arg id
(using the unaliased one isn't really a regression since that warning
checks if the undefined macro contains slash or backslash and only then
emits the warning – and no valid use will pass "-Ufoo/bar" or similar).

Also, lld has many JoinedOrSeparate aliases, and due to this bug it had
to explicitly call `getUnaliasedOption()` in a bunch of places, even
though that shouldn't be necessary by design. After this fix in Option,
these calls really don't have an effect any more, so remove them.

No intended behavior change.

(I accidentally fixed this bug while working on PR29106 but then
wondered why the warn_slash_u_filename broke. When I figured it out, I
thought it would make sense to land this in a separate commit.)

Differential Revision: https://reviews.llvm.org/D64156

llvm-svn: 365186
2019-07-05 11:45:24 +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
Guanzhong Chen e15dc95466 [wasm-ld] Add __global_base symbol to mark the value of --global-base
Summary:
This is needed for address sanitizer on Emscripten. As everything in
memory starts at the value passed to --global-base, everything before
that can be used as shadow memory.

This symbol is added so that the library for the ASan runtime can know
where the shadow memory ends and real memory begins.

This is split from D63742.

Reviewers: tlively, aheejin, sbc100

Subscribers: sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63833

llvm-svn: 364467
2019-06-26 20:12:33 +00:00
Sam Clegg 61d70e4a93 [WebAssembly] Error on archives without a symbol index
This is fairly common with wasm since GNU ar (most likely the system ar)
doesn't support the wasm object format so user who don't override AR
will end up with archives without an index.  We don't want to silently
ignore this issue.

In the future we could choose to instead behave like the ELF backend and
read the symbols from each object file in the archive if they are all of
the same type.  However, error'ing out seem like a conservative approach
for now.

Fixes: PR42376

Differential Revision: https://reviews.llvm.org/D63739

llvm-svn: 364338
2019-06-25 17:49:35 +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 59f959ff33 [WebAssembly] Relax signature checking for undefined functions that are not called directly
When function signatures don't match and the undefined function is not
called directly (i.e. only has its address taken) we don't issue a
warning or create a runtime thunk for the undefined function.

Instead in this case we simply use the defined version of the function.
This is possible since checking signatures of dynamic calls happens
at runtime so any invalid usage will still result in a runtime error.

This is needed to allow C++ programs to link without generating
warnings.  Its not uncommon in C++ for vtables to be populated by
function address whee the signature of the function is not known in the
compilation unit.  In this case clang declares the method as void(void)
and relies on the vtable caller casting the data back to the correct
signature.

Fixes: https://bugs.llvm.org/show_bug.cgi?id=40412

Differential Revision: https://reviews.llvm.org/D62153

llvm-svn: 361678
2019-05-24 22:45:08 +00:00
Sam Clegg a5ca34e6b3 [WebAssebmly] Add support for --wrap
The code for implementing this features is taken almost verbatim
from the ELF backend.

Fixes: https://bugs.llvm.org/show_bug.cgi?id=41681

Differential Revision: https://reviews.llvm.org/D62380

llvm-svn: 361639
2019-05-24 14:14:25 +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 4bce63a0e7 Reland: [WebAssembly] Add __start_/_stop_ symbols for data sections
This is a reland of rL361235.

Fixes https://bugs.llvm.org/show_bug.cgi?id=41565

Differential Revision: https://reviews.llvm.org/D61876

llvm-svn: 361476
2019-05-23 10:06:03 +00:00
Sam Clegg c0a4f45bcb Revert "[WebAssembly] Add __start_/_stop_ symbols for data sections"
This reverts commit 7804dbddcc.

This change broke a bunch of tests of the WebAssembly waterfall.
Will hopefully reland with increased test coverage.

llvm-svn: 361273
2019-05-21 17:16:33 +00:00
Rui Ueyama 35150bb534 [WebAssembly] Add --reproduce.
--reproduce is a convenient option for debugging. If you invoke lld
with `--reproduce=repro.tar`, it creates `repro.tar` with all input
files and the command line options given to the linker, so that it is
very easy to run lld with the exact same inputs.

ELF and Windows lld have this option.

This patch add that option to lld/wasm.

Differential Revision: https://reviews.llvm.org/D62170

llvm-svn: 361244
2019-05-21 11:52:14 +00:00