Summary:
- lowers @llvm.global_dtors by adding @llvm.global_ctors
functions which register the destructors with `__cxa_atexit`.
- impements @llvm.global_ctors with wasm start functions and linker metadata
See [here](https://github.com/WebAssembly/tool-conventions/issues/25) for more background.
Subscribers: jfb, dschuff, mgorny, jgravelle-google, aheejin, sunfish
Differential Revision: https://reviews.llvm.org/D41211
llvm-svn: 320774
Instead of having .o files contain linear-memory and function table
definitions, use imports. This is more consistent with the stack pointer
being imported, and it's consistent with the linker being the one to
decide whether linear memory and function table are imported or defined
in the linked output. This implements tool-conventions #23.
Differential Revision: https://reviews.llvm.org/D40875
llvm-svn: 319989
This is not currently valid by the wasm spec, however:
- It replaces doing set_global on an immutable global, which is also
not valid.
- It's expected be valid in the near future:
https://github.com/WebAssembly/threads/blob/master/proposals/threads/Globals.md
- This only occurs before linking, so a fully linked object will be
valid.
llvm-svn: 319810
Original change was rL319488.
This was reverted rL319602 due to a gcc 7.1 warning.
Differential Revision: https://reviews.llvm.org/D40772
llvm-svn: 319626
The LLVM "hidden" flag needs to be passed through the Wasm
intermediate objects in order for the linker to apply
it to the final Wasm object.
The corresponding change in LLD is here: https://github.com/WebAssembly/lld/pull/14
Patch by Nicholas Wilson
Differential Revision: https://reviews.llvm.org/D40442
llvm-svn: 319488
Generalize FixFunctionBitcasts to handle varargs functions. This in
particular fixes the case where clang bitcasts away a varargs when
calling a K&R-style function.
This avoids interacting with tricky ABI details because it operates
at the LLVM IR level before varargs ABI details are exposed.
This fixes PR35385.
llvm-svn: 319186
This ensures that each segment has a unique address.
Without this, consecutive zero sized symbols would
end up with the same address and the linker cannot
map symbols to unique data segments.
Differential Revision: https://reviews.llvm.org/D39107
llvm-svn: 316717
Summary:
Add LLVM_FORCE_ENABLE_DUMP cmake option, and use it along with
LLVM_ENABLE_ASSERTIONS to set LLVM_ENABLE_DUMP.
Remove NDEBUG and only use LLVM_ENABLE_DUMP to enable dump methods.
Move definition of LLVM_ENABLE_DUMP from config.h to llvm-config.h so
it'll be picked up by public headers.
Differential Revision: https://reviews.llvm.org/D38406
llvm-svn: 315590
functions.
This makes the ownership of the resulting MCObjectWriter clear, and allows us
to remove one instance of MCObjectStreamer's bizarre "holding ownership via
someone else's reference" trick.
llvm-svn: 315327
to WasmObjectWriter's constructor.
Fixes the same ownership issue for COFF that r315245 did for MachO:
WasmObjectWriter takes ownership of its MCWasmObjectTargetWriter, so we want to
pass this through to the constructor via a unique_ptr, rather than a raw ptr.
llvm-svn: 315260
Previously these were being included as both imports and
exports, with the import being satisfied by the export
(or some strong symbol) at runtime. However proved
unnecessary and actually complicated linking as it meant
there was not a 1-to-1 mapping between a wasm function
/global index and a linker symbol.
Differential Revision: https://reviews.llvm.org/D38246
llvm-svn: 314245
Add adds support for naming data segments. This is useful
useful linkers so that they can merge similar sections.
Differential Revision: https://reviews.llvm.org/D37886
llvm-svn: 313795
Add adds support for naming data segments. This is useful
useful linkers so that they can merge similar sections.
Differential Revision: https://reviews.llvm.org/D37886
llvm-svn: 313692
This means that we can honor -fdata-sections rather than
always creating a segment for each symbol.
It also allows for a followup change to add .init_array and friends.
Differential Revision: https://reviews.llvm.org/D37876
llvm-svn: 313395
Previously the 'Padding' argument was the number of padding
bytes to add. However most callers that use 'Padding' know
how many overall bytes they need to write. With the previous
code this would mean encoding the LEB once to find out how
many bytes it would occupy and then using this to calulate
the 'Padding' value.
See: https://reviews.llvm.org/D36595
Differential Revision: https://reviews.llvm.org/D37494
llvm-svn: 313393
- Create helper function for resolving weak references.
- Add test that preproduces the crash.
Differential Revision: https://reviews.llvm.org/D37916
llvm-svn: 313381
This is stepping stone towards honoring -fdata-sections
and letting the assembler decide how many wasm data
segments to create.
Differential Revision: https://reviews.llvm.org/D37834
llvm-svn: 313313
Summary: When implementing MCFillFragment, use the size of the fragment,
rather than the size of the section.
Patch by Dan Gohman
Differential Revision: https://reviews.llvm.org/D35090
llvm-svn: 307565
Model weakly defined symbols as symbols that are both
exports and imported and marked as weak. Local references
to the symbols refer to the import but the linker can
resolve this to the weak export if not strong symbol
is found at link time.
Differential Revision: https://reviews.llvm.org/D35029
llvm-svn: 307348
Previously we were generating a void(void) function type
for a weak alias. Update the weak-alias test case to
catch this.
Differential Revision: https://reviews.llvm.org/D34734
llvm-svn: 307194
The overal size of the data section (including BSS)
is otherwise not included in the wasm binary.
Differential Revision: https://reviews.llvm.org/D34657
llvm-svn: 306459
- Use auto where appropriate
- Use early return to reduce nesting
- Remove stray comment line
- Use C++ foreach over explicit iterator
Differential Revision: https://reviews.llvm.org/D34477
llvm-svn: 305971
The lld-x86_64-darwin13 is failing with:
error: unused function 'operator<<'
Wrap the declation in ifndef NDEBUG, which matches
what is done in MipsELFObjectWriter.cpp.
Differential Revision: https://reviews.llvm.org/D34384
llvm-svn: 305771
This fixes two build failures that only occur in certain
configurations:
- error: unused function 'operator<<'
- error: control reaches end of non-void function
Differential Revision: https://reviews.llvm.org/D34382
llvm-svn: 305770
This ensures that symbolic relocations are generated for stack
pointer manipulations.
These relocations are of type R_WEBASSEMBLY_GLOBAL_INDEX_LEB.
This change also adds support for reading relocations of this
type in WasmObjectFile.cpp.
Since its a globally imported symbol this does mean that
the get_global/set_global instruction won't be valid until
the objects are linked that global used in no longer an
imported global.
Differential Revision: https://reviews.llvm.org/D34172
llvm-svn: 305616
Previously we were writing the value function index space
value but for these types of relocations we want to be
writing the table element index space value.
Add a test case for these relocation types that fails
without this change.
Differential Revision: https://reviews.llvm.org/D33962
llvm-svn: 305253
This creates a new library called BinaryFormat that has all of
the headers from llvm/Support containing structure and layout
definitions for various types of binary formats like dwarf, coff,
elf, etc as well as the code for identifying a file from its
magic.
Differential Revision: https://reviews.llvm.org/D33843
llvm-svn: 304864
The change cleans up and unifies the handling of relocation
entries in WasmObjectWriter. Type index relocation no longer
need to be handled separately.
The only externally visible change should be that type
index relocations are no longer grouped at the end.
Differential Revision: https://reviews.llvm.org/D33918
llvm-svn: 304816
These methods looks like they were originally came from
MCELFObjectTargetWriter but they are never called by the
WasmObjectWriter.
Remove these methods meant the declaration of WasmRelocationEntry
could also move into the cpp file.
Differential Revision: https://reviews.llvm.org/D33905
llvm-svn: 304804
The size of this function was getting a little out of.
control. Split code for writing each section type into
seperate functions.
Differential Revision: https://reviews.llvm.org/D33792
llvm-svn: 304634
Dan Gohman