197 Commits

Author SHA1 Message Date
Derek Schuff
e65b9b04cd Revert "[WebAssembly] MC layer writes table symbols to object files"
This reverts commit e9f1ed2306b1b3aedcb1acef2b50e252a77a04b9.

Reverting because it depends on 38dfce706f
2021-01-15 15:50:22 -08:00
Andy Wingo
e9f1ed2306 [WebAssembly] MC layer writes table symbols to object files
Now that the linker handles table symbols, we can allow the frontend to
produce them.

Depends on D91870.

Differential Revision: https://reviews.llvm.org/D92215
2021-01-15 14:55:55 +01:00
Kazu Hirata
1d0bc05551 [llvm] Use llvm::append_range (NFC) 2021-01-06 18:27:33 -08:00
Sam Clegg
30d314aae1 [MC][WebAssembly] Avoid recalculating indexes in -gsplit-dwarf mode
Be consistent about asserting before setting WasmIndices.  Adding
these assertions revealed that we were duplicating a lot of work
and setting these indexed twice when running in DWO mode.

Differential Revision: https://reviews.llvm.org/D93650
2021-01-06 01:35:06 -08:00
Andy Wingo
9ad83fd6dc [WebAssembly] call_indirect causes indirect function table import
For wasm-ld table linking work to proceed, object files should indicate
if they use an indirect function table.  In the future this will be done
by the usual symbols and relocations mechanism, but until that support
lands in the linker, the presence of an `__indirect_function_table` in
the object file's import section shows that the object file needs an
indirect function table.

Prior to https://reviews.llvm.org/D91637, this condition was met by all
object files residualizing an `__indirect_function_table` import.

Since https://reviews.llvm.org/D91637, the intention has been that only
those object files needing an indirect function table would have the
`__indirect_function_table` import.  However, we missed the case of
object files which use the table via `call_indirect` but which
themselves do not declare any indirect functions.

This changeset makes it so that when we lower a call to `call_indirect`,
that we ensure that a `__indirect_function_table` symbol is present and
that it will be propagated to the linker.

A followup patch will revise this mechanism to make an explicit link
between `call_indirect` and its associated indirect function table; see
https://reviews.llvm.org/D90948.

Differential Revision: https://reviews.llvm.org/D92840
2021-01-05 11:09:24 +01:00
Derek Schuff
8d396acac3 [WebAssembly] Support COMDAT sections in assembly syntax
This CL changes the asm syntax for section flags, making them more like ELF
(previously "passive" was the only option). Now we also allow "G" to designate
COMDAT group sections. In these sections we set the appropriate comdat flag on
function symbols, and also avoid auto-creating a new section for them.

This also adds asm-based tests for the changes D92691 to go along with
the direct-to-object tests.

Differential Revision: https://reviews.llvm.org/D92952
This is a reland of rG4564553b8d8a with a fix to the lit pipeline in
llvm/test/MC/WebAssembly/comdat.ll
2020-12-10 16:43:59 -08:00
Derek Schuff
dd1aa4fdd8 Revert "[WebAssembly] Support COMDAT sections in assembly syntax"
This reverts commit 4564553b8d8ab81dc21431a35275581cb42329c8.
It broke several buildbots.
2020-12-10 15:55:33 -08:00
Derek Schuff
4564553b8d [WebAssembly] Support COMDAT sections in assembly syntax
This CL changes the asm syntax for section flags, making them more like ELF
(previously "passive" was the only option). Now we also allow "G" to designate
COMDAT group sections. In these sections we set the appropriate comdat flag on
function symbols, and also avoid auto-creating a new section for them.

This also adds asm-based tests for the changes D92691 to go along with
the direct-to-object tests.

Differential Revision: https://reviews.llvm.org/D92952
2020-12-10 14:46:24 -08:00
Derek Schuff
0a391060f1 [WebAssembly] Add Object and ObjectWriter support for wasm COMDAT sections
Allow sections to be placed into COMDAT groups, in addtion to functions and data
segments.

Also make section symbols unnamed, which allows sections with identical names
(section names are independent of their section symbols, but previously we
gave the symbols the same name as their sections, which results in collisions
when sections are identically-named).

Differential Revision: https://reviews.llvm.org/D92691
2020-12-07 12:12:44 -08:00
Andy Wingo
d823cc7cad [WebAssembly][MC] Fix placement of table section
The table section goes after functions.

Differential Revision: https://reviews.llvm.org/D92323
2020-12-07 16:17:32 +01:00
Fangrui Song
9c53b2adc8 [MC] Delete unused declarations
Notes:

* llvm::createAsmStreamer: it has been moved to TargetRegistry.h
* (anon ns)::WasmObjectWriter::updateCustomSectionRelocations: remnant of D46335
* COFFAsmParser::ParseSEHRegisterNumber: remnant of D66625
* llvm::CodeViewContext::isValidCVFileNumber: accidentally added by r279847
2020-12-06 15:36:39 -08:00
Andy Wingo
feac819e50 [MC][WebAssembly] Only emit indirect function table import if needed
The indirect function table, synthesized by the linker, is needed if and
only if there are TABLE_INDEX relocs.

Differential Revision: https://reviews.llvm.org/D91637
2020-11-25 08:38:43 -08:00
Andy Wingo
1933c9d41a [WebAssembly] Factor out WasmTableType in binary format
This commit factors out a WasmTableType definition from WasmTable, as is
the case for WasmGlobal and other data types.  Also add support for
extracting the SymbolName for a table from the linking section's symbol
table.

Differential Revision: https://reviews.llvm.org/D91849
2020-11-25 08:00:08 -08:00
Wouter van Oortmerssen
16f02431dc [WebAssembly] Added R_WASM_FUNCTION_OFFSET_I64 for use with DWARF DW_AT_low_pc
Needed for wasm64, see discussion in https://reviews.llvm.org/D91203

Differential Revision: https://reviews.llvm.org/D91395
2020-11-13 09:32:31 -08:00
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
Derek Schuff
77973f8dee [WebAssembly] Add support for DWARF type units
Since Wasm comdat sections work similarly to ELF, we can use that mechanism
    to eliminate duplicate dwarf type information in the same way.

    Differential Revision: https://reviews.llvm.org/D88603
2020-10-28 17:41:22 -07:00
Derek Schuff
44eea0b1a7 Revert "[WebAssembly] Add support for DWARF type units"
This reverts commit bcb8a119df210753c5f1a3ac346d49597fef0f51.
2020-10-27 17:57:32 -07:00
Derek Schuff
bcb8a119df [WebAssembly] Add support for DWARF type units
Since Wasm comdat sections work similarly to ELF, we can use that mechanism
to eliminate duplicate dwarf type information in the same way.

Differential Revision: https://reviews.llvm.org/D88603
2020-10-27 17:13:41 -07:00
Paulo Matos
69e2797eae [WebAssembly] Implementation of (most) table instructions
Implementation of instructions table.get, table.set, table.grow,
table.size, table.fill, table.copy.

Missing instructions are table.init and elem.drop as they deal with
element sections which are not yet implemented.

Added more tests to tables.s

Differential Revision: https://reviews.llvm.org/D89797
2020-10-23 08:42:54 -07:00
Paulo Matos
388fb67b0d [WebAssembly] Added .tabletype to asm and multiple table support in obj files
Adds more testing in basic-assembly.s and a new test tables.s.
Adds support to yaml reading and writing of tables as well.

Differential Revision: https://reviews.llvm.org/D88815
2020-10-13 07:52:23 -07:00
Benjamin Kramer
b59dff4b16 [wasm] Move WasmTraits.h to BinaryFormat
There's no dependency on Object in there and this avoids a cyclic
dependency between libMC and libObject.
2020-09-28 22:07:28 +02:00
Heejin Ahn
4c41fb5ad7 [WebAssembly] Use wasm::Signature for in ObjectWriter (NFC)
There are two `WasmSignature` structs, one in
include/llvm/BinaryFormat/Wasm.h and the other in
lib/MC/WasmObjectWriter.cpp. I don't know why they got separated in this
way in the first place, but it seems we can unify them to use the one in
Wasm.h for all cases.

Reviewed By: dschuff, sbc100

Differential Revision: https://reviews.llvm.org/D88428
2020-09-28 10:46:55 -07:00
Dominic Chen
9c7b58080e
[WebAssembly][MC] Fix computation of relative symbol offset
For relative symbols, add its offset when computing relocation value.
Also, warn on unsupported absolute symbols.

Differential Revision: https://reviews.llvm.org/D87407
2020-09-22 00:53:23 -04:00
Derek Schuff
0ff28fa6a7 Support dwarf fission for wasm object files
Initial support for dwarf fission sections (-gsplit-dwarf) on wasm.
The most interesting change is support for writing 2 files (.o and .dwo) in the
wasm object writer. My approach moves object-writing logic into its own function
and calls it twice, swapping out the endian::Writer (W) in between calls.
It also splits the import-preparation step into its own function (and skips it when writing a dwo).

Differential Revision: https://reviews.llvm.org/D85685
2020-09-17 14:42:41 -07:00
Simon Pilgrim
48b510c4bc [NFC] Fix compiler warnings due to integer comparison of different signedness
Fix by directly using INT_MAX and INT32_MAX.

Patch by: @nullptr.cpp (Yang Fan)

Differential Revision: https://reviews.llvm.org/D87347
2020-09-11 15:32:03 +01:00
Wouter van Oortmerssen
cc1b9b680f [WebAssembly] 64-bit (function) pointer fixes.
Accounting for the fact that Wasm function indices are 32-bit, but in wasm64 we want uniform 64-bit pointers.
Includes reloc types for 64-bit table indices.

Differential Revision: https://reviews.llvm.org/D83729
2020-07-16 14:10:22 -07:00
Wouter van Oortmerssen
fd0964ae83 [WebAssembly] fix gcc 10 warning 2020-07-07 17:55:37 -07:00
Wouter van Oortmerssen
4d135b0446 [WebAssembly] 64-bit memory limits 2020-07-06 12:40:45 -07:00
Sam Clegg
e49584a34a [WebAssembly] Fix for use of uninitialized member in WasmObjectWriter.cpp
Currently, section indices may be passed uninitialized by value if
writing the section fails. Removes section indices form class
initialization and returns them from the write{Code,Data}Section
function calls instead.

Patch by Gui Andrade!

Differential Revision: https://reviews.llvm.org/D81702
2020-06-23 15:26:18 -07:00
Sam Clegg
79aad89d8d [WebAssembly] Add support for externalref to MC and wasm-ld
This allows code for handling externref values to be processed by the
assembler and linker.

Differential Revision: https://reviews.llvm.org/D81977
2020-06-22 15:57:24 -07:00
Sam Clegg
7ee758d691 [WebAssembly] MC: Fix for data aliases with offsets (getelementptr)
For some reason we hadn't seen such cases in the wild which makes
me think that clang and rustc don't generate these.  In the bug which
reproduces it only occurs with LTO so my guess is that some LTO pass
is creating this alias + gep.

See: https://github.com/emscripten-core/emscripten/issues/8731

Differential Revision: https://reviews.llvm.org/D79462
2020-06-17 16:25:50 -07:00
Wouter van Oortmerssen
3b29376e3f [WebAssembly] Adding 64-bit version of R_WASM_MEMORY_ADDR_* relocs
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
2020-06-15 10:07:42 -07:00
Sam Clegg
81443ac1bc [WebAssembly] Add placeholders for R_WASM_TABLE_INDEX_REL_SLEB relocations
Previously in the object format we punted on this and simply wrote
zeros (and didn't include the function in the elem segment).  With
this change we write a meaningful value which is the segment
relative table index of the associated function.

This matches the that wasm-ld produces in `-r` mode.  This inconsistency
between the output the MC object writer and the wasm-ld object
writer could cause warnings to be emitted when reading back in the
output of `wasm-ld -r`.  See:
https://github.com/emscripten-core/emscripten/issues/11217

This only applies to this one relocation type which is only generated
when compiling in PIC mode.

Differential Revision: https://reviews.llvm.org/D80774
2020-05-29 10:57:26 -07:00
Sam Clegg
0a6c4d8d2e [WebAssmebly] Add support for defined wasm globals in MC and lld
This change add support for defined wasm globals in the .s format,
the MC layer, and wasm-ld

Currently there is no support custom initialization and all wasm
globals are initialized to zero.

Fixes: PR45742

Differential Revision: https://reviews.llvm.org/D79137
2020-04-30 12:43:15 -07:00
Simon Pilgrim
bcd7f77713 MCObjectWriter.h - remove Endian.h/EndianStream.h/raw_ostream.h includes. NFC
Push these includes down to the the writers that actually need them, a number of which were implicitly relying on the MCObjectWriter.h.
2020-04-17 10:44:08 +01:00
Wouter van Oortmerssen
48139ebc3a [WebAssembly] Add int32 DW_OP_WASM_location variant
This to allow us to add reloctable global indices as a symbol.
Also adds R_WASM_GLOBAL_INDEX_I32 relocation type to support it.

See discussion in https://github.com/WebAssembly/debugging/issues/12
2020-04-16 16:32:17 -07:00
Fangrui Song
7d1ff446b6 [MC] Rename MCSection*::getSectionName() to getName(). NFC
A pending change will merge MCSection*::getName() to MCSection::getName().
2020-04-15 16:48:14 -07:00
Sam Clegg
3ea1c62cba [WebAssembly] Emit .llvmcmd and .llvmbc as custom sections
Fixes: https://bugs.llvm.org/show_bug.cgi?id=45362

Differential Revision: https://reviews.llvm.org/D77115
2020-04-14 13:24:18 -07:00
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
Sam Clegg
b4f4e370b5 [WebAssebmly][MC] Support .import_name/.import_field asm directives
Convert the MC test to use asm rather than bitcode.

This is a precursor to https://reviews.llvm.org/D70520.

Differential Revision: https://reviews.llvm.org/D70877
2019-12-06 15:09:56 -08:00
Sam Clegg
079cba04bf [MC][WebAssembly] Error on data symbols in the text section.
Previously we had an assert but this can actually occur in valid user
code so we need to handle this in release builds too.

Differential Revision: https://reviews.llvm.org/D67997

llvm-svn: 372934
2019-09-25 23:33:16 +00:00
Dan Gohman
da84b688f9 [WebAssembly] Make __attribute__((used)) not imply export.
Add an WASM_SYMBOL_NO_STRIP flag, so that __attribute__((used)) doesn't
need to imply exporting. When targeting Emscripten, have
WASM_SYMBOL_NO_STRIP imply exporting.

Differential Revision: https://reviews.llvm.org/D62542

llvm-svn: 370415
2019-08-29 22:40:00 +00:00
Fangrui Song
e828ce1b88 [WebAssembly][MC] Fix -Wunused-variable in -DLLVM_ENABLE_ASSERTIONS=off builds after r369317
llvm-svn: 369318
2019-08-20 02:02:57 +00:00
Sam Clegg
ecc5e8084f [WebAssembly][MC] Simplify WasmObjectWriter::recordRelocation. NFC.
WebAssembly doesn't support PC relative relocation or relocation
expressions that can't be reduced to single symbol.

The only support for we have for fixups involving two symbols are when
both symbols are defined and withing the same section.  In this case
evaluateFixup will already have evaluated to the expression before
calling recordRelocation.

llvm-svn: 369317
2019-08-20 00:33:50 +00:00
Jonas Devlieghere
0eaee545ee [llvm] 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.

llvm-svn: 369013
2019-08-15 15:54:37 +00:00
Fangrui Song
b251cc0d91 Delete dead stores
llvm-svn: 365903
2019-07-12 14:58:15 +00:00
Keno Fischer
cadcb9eb61 [WebAssembly] Fix list of relocations with addends in lld
Summary:
The list of relocations with addend in lld was missing `R_WASM_MEMORY_ADDR_REL_SLEB`,
causing `wasm-ld` to generate corrupted output. This fixes that problem and while
we're at it pulls the list of such relocations into the Wasm.h header, to avoid
duplicating it in multiple places.

Reviewers: sbc100
Differential Revision: https://reviews.llvm.org/D63696

llvm-svn: 364367
2019-06-26 00:52:42 +00:00
Fangrui Song
efd94c56ba Use llvm::stable_sort
While touching the code, simplify if feasible.

llvm-svn: 358996
2019-04-23 14:51:27 +00:00
Thomas Lively
fef8de66a6 [WebAssembly] Add DataCount section to object files
Summary:
This ensures that object files will continue to validate as
WebAssembly modules in the presence of bulk memory operations. Engines
that don't support bulk memory operations will not recognize the
DataCount section and will report validation errors, but that's ok
because object files aren't supposed to be run directly anyway.

Reviewers: aheejin, dschuff, sbc100

Subscribers: jgravelle-google, hiraditya, sunfish, rupprecht, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60623

llvm-svn: 358315
2019-04-12 22:27:48 +00:00
Sam Clegg
2a7cac932b [WebAssembly] Add new explicit relocation types for PIC relocations
See https://github.com/WebAssembly/tool-conventions/pull/106

Differential Revision: https://reviews.llvm.org/D59907

llvm-svn: 357710
2019-04-04 17:43:50 +00:00