Some projects use the constructor attribute on functions that also
return values. In this case we just ignore them.
The error was reported in the libgpg-error project that marks
gpg_err_init with the `__constructor__` attribute.
Differential Revision: https://reviews.llvm.org/D81962
This adds 4 new reloc types.
A lot of code that previously assumed any memory or offset values could be contained in a uint32_t (and often truncated results from functions returning 64-bit values) have been upgraded to uint64_t. This is not comprehensive: it is only the values that come in contact with the new relocation values and their dependents.
A new tablegen mapping was added to automatically upgrade loads/stores in the assembler, which otherwise has no way to select for these instructions (since they are indentical other than for the offset immediate). It follows a similar technique to https://reviews.llvm.org/D53307
Differential Revision: https://reviews.llvm.org/D81704
Summary:
This patch fixes a bug where initialization code for .bss segments was
emitted in the memory initialization function even though the .bss
segments were discounted in the datacount section and omitted in the
data section. This was producing invalid binaries due to out-of-bounds
segment indices on the memory.init and data.drop instructions that
were trying to operate on the nonexistent .bss segments.
Reviewers: sbc100
Subscribers: dschuff, jgravelle-google, aheejin, sunfish, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D80354
Summary:
The WebAssembly backend automatically lowers atomic operations and TLS
to nonatomic operations and non-TLS data when either are present and
the atomics or bulk-memory features are not present, respectively. The
resulting object is no longer thread-safe, so the linker has to be
told not to allow it to be linked into a module with shared
memory. This was previously done by disallowing the 'atomics' feature,
which prevented any objct with its atomic operations or TLS removed
from being linked with any object containing atomics or TLS, and
therefore preventing it from being linked into a module with shared
memory since shared memory requires atomics.
However, as of https://github.com/WebAssembly/threads/issues/144, the
validation rules are relaxed to allow atomic operations to validate
with unshared memories, which makes it perfectly safe to link an
object with stripped atomics and TLS with another object that still
contains TLS and atomics as long as the resulting module has an
unshared memory. To allow this kind of link, this patch disallows a
pseudo-feature 'shared-mem' rather than 'atomics' to communicate to
the linker that the object is not thread-safe. This means that the
'atomics' feature is available to accurately reflect whether or not an
object has atomics enabled.
As a drive-by tweak, this change also requires that bulk-memory be
enabled in addition to atomics in order to use shared memory. This is
because initializing shared memories requires bulk-memory operations.
Reviewers: aheejin, sbc100
Subscribers: dschuff, jgravelle-google, hiraditya, sunfish, jfb, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D79542
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
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
Summary:
A previous change (53211a) had updated the argument parsing to handle
large max memories, but 4294967296 would still wrap to zero after the
options were parsed. This change updates the configuration to use a
64-bit integer to store the max memory to avoid that overflow.
Reviewers: sbc100
Subscribers: dschuff, jgravelle-google, aheejin, sunfish, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D77437
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.
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
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
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
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
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
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
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
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
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
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
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
This puts handling of undefined symbols in a single location. Its
also more in line with the ELF backend which only reports undefined
symbols based on relocations.
One side effect is that we no longer report undefined symbols that are
only referenced in GC'd sections.
This also fixes a crash reported in the emscripten toolchain:
https://github.com/emscripten-core/emscripten/issues/8930.
Differential Revision: https://reviews.llvm.org/D64280
llvm-svn: 365553
This should always have been ".data". Without this we treat the
section as a user-defined section in other places (such as the
generation of __start/__stop symbols).
Differential Revision: https://reviews.llvm.org/D64439
llvm-svn: 365547
We should be generating one __start/__stop pair per output segment
not per input segment. The test wasn't catching this because it was
only linking a single object file.
Fixes PR41565
Differential Revision: https://reviews.llvm.org/D64148
llvm-svn: 365308
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
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
When a function is excluded via comdat we shouldn't add it to the
final list of init functions.
Differential Revision: https://reviews.llvm.org/D62983
llvm-svn: 362769
Summary:
Add the names of the input files responsible for each error to the
messages.
Reviewers: sbc100, azakai
Subscribers: dschuff, jgravelle-google, aheejin, sunfish, jfb, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62704
llvm-svn: 362162
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
Summary:
Before we can assign entries in the function of global index space
we need to know the total number of function and global imports
respectively.
To avoid programmer error this change seals that imports section before
assigned function and global index space. Any attempt to add an import
after the section is sealed will assert.
The lack this such as check caused https://reviews.llvm.org/D61876
to be reverted. I'm also trying to craft a test case the this
failure.
Subscribers: dschuff, jgravelle-google, aheejin, sunfish, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62240
llvm-svn: 361470
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
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
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
The current PIC model for WebAssembly is more like ELF in that it
allows symbol interposition.
This means that more functions end up being addressed via the GOT
and fewer directly added to the wasm table.
One effect is a reduction in the number of wasm table entries similar
to the previous attempt in https://reviews.llvm.org/D61539 which was
reverted.
Differential Revision: https://reviews.llvm.org/D61772
llvm-svn: 360402
When generating PIC output only relocations of type
R_WASM_TABLE_INDEX_REL_SLEB should generate table entries.
R_WASM_TABLE_INDEX_I32 get resolved at runtime via the auto-generated
__wasm_apply_relocs functions.
R_WASM_TABLE_INDEX_SLEB are not allowed in PIC code.
Differential Revision: https://reviews.llvm.org/D61539
llvm-svn: 360165
Make some small adjustment while touching the code: make parameters
const, use less_first(), etc.
Differential Revision: https://reviews.llvm.org/D60989
llvm-svn: 358943
We can't (currently) meaningfully resolve certain types of relocations
against undefined data symbols. Previously when `--allow-undefined` was
used we were treating such relocation much like weak data symbols and
simply inserting zeros. This change turns such use cases in to an
error.
This means that `--allow-undefined` is no longer effective for data
symbols.
Fixes https://bugs.llvm.org/show_bug.cgi?id=40364
Differential Revision: https://reviews.llvm.org/D60882
llvm-svn: 358899
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
This should have been part of rL357710 but was overlooked because
in our test code the function in question was also used in other
relocations that caused it to be added to the table anyway.
Differential Revision: https://reviews.llvm.org/D60296
llvm-svn: 357737
See https://reviews.llvm.org/D59860
The initial version of this change effected more than just the
error message. This version is scoped down to only effect the error
itself.
llvm-svn: 357328
Summary:
Makes it a linker error if the "atomics" feature is used but the user
does not opt in to shared memory or if "atomics" is disallowed but the
user does opt in to shared memory. Also check that an appropriate max
memory size is supplied if shared memory is used.
Reviewers: sbc100, aheejin
Subscribers: dschuff, jgravelle-google, sunfish, jfb, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D59281
llvm-svn: 357310
Also Revert "[WebAssembly] Fix typo from rL357143"
This reverts commit 0805ec5f7b and
a9958fc30d
(rL357143 and rL357144)
They cause failures with address-taken extern (JS) functions
in emscripten.
llvm-svn: 357224
This change implements lowering of references global symbols in PIC
mode.
This change implements lowering of global references in PIC mode using a
new @GOT reference type. @GOT references can be used with function or
data symbol names combined with the get_global instruction. In this case
the linker will insert the wasm global that stores the address of the
symbol (either in memory for data symbols or in the wasm table for
function symbols).
For now I'm continuing to use the R_WASM_GLOBAL_INDEX_LEB relocation
type for this type of reference which means that this relocation type
can refer to either a global or a function or data symbol. We could
choose to introduce specific relocation types for GOT entries in the
future. See the current dynamic linking proposal:
https://github.com/WebAssembly/tool-conventions/blob/master/DynamicLinking.md
Differential Revision: https://reviews.llvm.org/D54647
llvm-svn: 357022
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
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
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
For these types of relocations an absolute memory address is
required which is not possible for undefined data symbols. For symbols
that can be undefined at link time (i.e. external data symbols in
shared libraries) a different type of relocation (i.e. via a GOT) will
be needed.
Differential Revision: https://reviews.llvm.org/D59337
llvm-svn: 356310
When linking shared libraries, we import a mutable wasm global
to represent the address of each undefined data symbol.
This is a step towards supporting dynamic linking and shared
libraries.
Differential Revision: https://reviews.llvm.org/D59270
llvm-svn: 355988
This matches the ELF does. Update the comment in ELF/Symbols.h and
duplicate it in wasm/Symbols.h
This a followup on rL355580 and rL355577.
Differential Revision: https://reviews.llvm.org/D59075
llvm-svn: 355737
Add a flag to allow symbols to have a wasm import name which differs from the
linker symbol name, allowing the linker to link code using the import_module
attribute.
Differential Revision: https://reviews.llvm.org/D57632
llvm-svn: 353473
Summary:
This patch fixes clang-tidy warnings on wasm-only files.
The list of checks used is:
`-*,clang-diagnostic-*,llvm-*,misc-*,-misc-unused-parameters,readability-identifier-naming,modernize-*`
(LLVM's default .clang-tidy list is the same except it does not have
`modernize-*`.)
The list of fixes are:
- Variable names start with an uppercase letter
- Function names start with a lowercase letter
- Use `auto` when you use casts so the type is evident
Reviewers: sbc100
Subscribers: dschuff, jgravelle-google, sunfish, llvm-commits
Differential Revision: https://reviews.llvm.org/D57499
llvm-svn: 353076
Fixes: https://bugs.llvm.org/show_bug.cgi?id=37168
This is only a first pass at supporting these custom import
modules. In the long run we most likely want to treat these
kinds of symbols very differently. For example, it should not
be possible to resolve such as symbol at static link type.
Differential Revision: https://reviews.llvm.org/D45796
llvm-svn: 352828
Change the way we create the symbol table to be closer to how its done
on ELF. Now the output symbol table matches the internal symtab order
and includes local and undefined symbols.
Fixes PR40204
Differential Revision: https://reviews.llvm.org/D56947
llvm-svn: 352645
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
This reverts commit 71eaf61c6c121c8c3bcaf3490557e92cf81599cb. One of
the lld tests was breaking, so revert this change until it is fixed.
llvm-svn: 351409
Summary:
At the beginning of `assignIndexes() function, when `FunctionIndex` and
`GlobalIndex` variables are created, `InputFunctions` and `InputGlobals`
vectors are guaranteed to be empty, because those vectors are only
populated in `assignIndexes()` function. Current code looks like they
are nonempty, so this patch deletes them for better readability.
Reviewers: sbc100
Subscribers: dschuff, jgravelle-google, sunfish, llvm-commits
Differential Revision: https://reviews.llvm.org/D54687
llvm-svn: 347272
`--no-demangle` now also applies to the name section. This change
was motivated by the rust team that have a slightly different name
mangling scheme to the standard C++ itanium one and prefer to do their
de-mangling as a post-link setp.
Patch by Alex Crichton!
Differential Revision: https://reviews.llvm.org/D54279
llvm-svn: 346516
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
This change effects the behavior of --export-all. Previously
--export-all would only effect symbols that survived GC. Now
--export-all will prevent any non-local symbols from being GCed.
Differential Revision: https://reviews.llvm.org/D48673
llvm-svn: 335878
Function symbols that come from bitcode have not signatures.
After LTO when the real symbols are read in we need to make
sure that we set the signature on the existing symbol.
the signature-less undefined functions.
Differential Revision: https://reviews.llvm.org/D48693
llvm-svn: 335875
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
The DEBUG() macro is very generic so it might clash with other projects.
The renaming was done as follows:
- git grep -l 'DEBUG' | xargs sed -i 's/\bDEBUG\s\?(/LLVM_DEBUG(/g'
- git diff -U0 master | ../clang/tools/clang-format/clang-format-diff.py -i -p1 -style LLVM
Differential Revision: https://reviews.llvm.org/D44977
llvm-svn: 332351
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
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
Enables cleaning up confusion between which name variables are mangled
and which are unmangled, and --print-gc-sections then excersises and
tests that.
Differential Revision: https://reviews.llvm.org/D44440
llvm-svn: 330449
Copy user-defined custom sections into the output, concatenating
sections with the same name.
Differential Revision: https://reviews.llvm.org/D45340
llvm-svn: 329717
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
This reduces the number of lookups to one per COMDAT group, rather than
one per symbol in a COMDAT group.
Differential Revision: https://reviews.llvm.org/D44344
llvm-svn: 327523
Previously, Config->InitialMemory/MaxMemory were hooked up to some
commandline args but had no effect at all.
Differential Revision: https://reviews.llvm.org/D44393
llvm-svn: 327508
This bug was found by accident while trying to expand out testcases
for imported symbols, and is covered by the additional test case.
Differential Revision: https://reviews.llvm.org/D44331
llvm-svn: 327290
This matches the existing ordering that's been there for globals
for a while (__stack_pointer coming first).
Differential Revision: https://reviews.llvm.org/D44333
llvm-svn: 327286
Previously we created __wasm_call_ctors with null InputFunction, and
added the InputFunction later. Now we create the SyntheticFunction with
null body, and set the body later.
Differential Revision: https://reviews.llvm.org/D44206
llvm-svn: 327149
This avoids the Writer unnecessarily having a member to retain ownership
of the function body.
Differential Revision: https://reviews.llvm.org/D43933
llvm-svn: 326580
Let X and Y be types. Previously, functions F(X, Y) and G(Y, X) had
the same hash value because their hash values are computed as follows:
hash(F) = hash(X) + hash(Y)
hash(G) = hash(Y) + hash(X)
This patch fixes the issue by using hash_combine.
Differential Revision: https://reviews.llvm.org/D43856
llvm-svn: 326336
These output section names are ELF-specific. We shouldn't have this rule
for WebAssembly.
Differential Revision: https://reviews.llvm.org/D43712
llvm-svn: 326289
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
Wouter van Oortmerssen