This `R_WASM_MEMORY_ADDR_SELFREL_I32` relocation represents an offset
between its relocating address and the symbol address. It's very similar
to `R_X86_64_PC32` but restricted to be used for only data segments.
```
S + A - P
```
A: Represents the addend used to compute the value of the relocatable
field.
P: Represents the place of the storage unit being relocated.
S: Represents the value of the symbol whose index resides in the
relocation entry.
Proposal: https://github.com/WebAssembly/tool-conventions/issues/162
Differential Revision: https://reviews.llvm.org/D96659
The WebAssembly text and binary formats have different operand orders
for the "type" and "table" fields of call_indirect (and
return_call_indirect). In LLVM we use the binary order for the MCInstr,
but when we produce or consume the text format we should use the text
order. For compilation units targetting WebAssembly 1.0 (without the
reference types feature), we omit the table operand entirely.
Differential Revision: https://reviews.llvm.org/D97761
If the reference-types feature is enabled, call_indirect will explicitly
reference its corresponding function table via TABLE_NUMBER
relocations against a table symbol.
Also, as before, address-taken functions can also cause the function
table to be created, only with reference-types they additionally cause a
symbol table entry to be emitted.
Differential Revision: https://reviews.llvm.org/D90948
If the reference-types feature is enabled, call_indirect will explicitly
reference its corresponding function table via `TABLE_NUMBER`
relocations against a table symbol.
Also, as before, address-taken functions can also cause the function
table to be created, only with reference-types they additionally cause a
symbol table entry to be emitted.
We abuse the used-in-reloc flag on symbols to indicate which tables
should end up in the symbol table. We do this because unfortunately
older wasm-ld will carp if it see a table symbol.
Differential Revision: https://reviews.llvm.org/D90948
Fixes assert in: https://bugs.llvm.org/show_bug.cgi?id=49036
getWasmSection creates sections if they don't exist, but doesn't add them to the Symbols table. This may cause problems in subsequent calls to getOrCreateSymbol which checks this table, the calls createSymbol assuming it doesn't exist, which then checks UsedNames and finds out it does exist, causing an assert on trying to rename a non-temp symbol.
I tried also fixing the somewhat unintuitive forced suffixing (adding `0`), but it turns out that WasmObjectWriter currently assumes these section symbols are unique, so that may have to be a separate fix: https://bugs.llvm.org/show_bug.cgi?id=49252
Also worth noting is that getWasmSection calling createSymbol may not be correct to start with, given that createSymbol seems to assume it is creating non-section symbols. But again, for a future fix.
Related: where some of this was introduced: 8d396acac3
Differential Revision: https://reviews.llvm.org/D96473
This allows data sections that don't start with `.data` to be
used/created.
Without this, clang's `__attribute__((section("foo")))` would
generate assembly that would not parse.
Differential Revision: https://reviews.llvm.org/D96233
When calculating the symbol offsets to write as provisitonal values
in object files we are only interested in the offset of the symbol
itself. For aliases this offset already includes the offset of the
base symbol.
The testin question was added back in https://reviews.llvm.org/D87407
but I believe the expectations here were incorrect. sym_a lives
at offset 4 and sym_b lives 4 bytes into that (should be 8).
The addresses of the 3 symbosl in this object file are:
foo : 0
sym_a: 4
sym_b: 8
Differential Revision: https://reviews.llvm.org/D96234
This updates InstPrinter and AsmParser for `delegate` and `catch_all`
instructions. Both will reject programs with multiple `catch_all`s per a
single `try`. And InstPrinter uses `EHInstStack` to figure out whether
to print catch label comments: It does not print catch label comments
for second `catch` or `catch_all` in a `try`.
Reviewed By: aardappel
Differential Revision: https://reviews.llvm.org/D94051
We used to require .functype immediately follows the label it sets the type of, but not all Clang output follows this rule.
Now we simply allow it on any symbol, but only assume its a function start for a defined symbol, which is simpler and more general.
Fixes (part of) https://bugs.llvm.org/show_bug.cgi?id=49036
Differential Revision: https://reviews.llvm.org/D96165
This reverts commit d806618636.
Review: https://reviews.llvm.org/D92215
We had issues where older versions of wasm-ld were crashing on object
files containing a table symbol. We decided that the best strategy
going forward is to only generate these symbol if refernece types is
enabled. Without reference types enabled we should never geneate a
table symbol or a TABLE_NUMBER relocation.
This revert is in addition to the one already reverted in
https://reviews.llvm.org/D95005.
The plan is to re-land these in updated form after the llvm 12 branch.
Differential Revision: https://reviews.llvm.org/D95420
This reverts commit 418df4a6ab.
This change broke emscripten tests, I believe because it started
generating 5-byte a wide table index in the call_indirect instruction.
Neither v8 nor wabt seem to be able to handle that. The spec
currently says that this is single 0x0 byte and:
"In future versions of WebAssembly, the zero byte occurring in the
encoding of the call_indirectcall_indirect instruction may be used to
index additional tables."
So we need to revisit this change. For backwards compat I guess
we need to guarantee that __indirect_function_table is always at
address zero. We could also consider making this a single-byte
relocation with and assert if have more than 127 tables (for now).
Differential Revision: https://reviews.llvm.org/D95005
This patch changes to make call_indirect explicitly refer to the
corresponding function table, residualizing TABLE_NUMBER relocs against
it.
With this change, wasm-ld now sees all references to tables, and can
link multiple tables.
Differential Revision: https://reviews.llvm.org/D90948
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
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
- Updates InstPrinter to handle `catch_all`.
- Makes `rethrow` condition an early exit from the function to make the
rest simpler.
- Unify label and catch counters. They don't need to be counted
separately and this will help `delegate` instruction later.
- Removes `LastSeenEHInst` field. This was first introduced to handle
when there are more than one `catch` blocks per `try`, but this was
not implemented correctly and not being used at the moment anyway.
- Reenables all tests in cfg-stackify-eh.ll that don't deal with unwind
destination mismatches, which will be handled in a later CL.
Reviewed By: dschuff, tlively, aardappel
Differential Revision: https://reviews.llvm.org/D94043
This removes `exnref` type and `br_on_exn` instruction. This is
effectively NFC because most uses of these were already removed in the
previous CLs.
Reviewed By: dschuff, tlively
Differential Revision: https://reviews.llvm.org/D94041
This implements basic instructions for the new spec.
- Adds new versions of instructions: `catch`, `catch_all`, and `rethrow`
- Adds support for instruction selection for the new instructions
- `catch` needs a custom routine for the same reason `throw` needs one,
to encode `__cpp_exception` tag symbol.
- Updates `WebAssembly::isCatch` utility function to include `catch_all`
and Change code that compares an instruction's opcode with `catch` to
use that function.
- LateEHPrepare
- Previously in LateEHPrepare we added `catch` instruction to both
`catchpad`s (for user catches) and `cleanuppad`s (for destructors).
In the new version `catch` is generated from `llvm.catch` intrinsic
in instruction selection phase, so we only need to add `catch_all`
to the beginning of cleanup pads.
- `catch` is generated from instruction selection, but we need to
hoist the `catch` instruction to the beginning of every EH pad,
because `catch` can be in the middle of the EH pad or even in a
split BB from it after various code transformations.
- Removes `addExceptionExtraction` function, which was used to
generate `br_on_exn` before.
- CFGStackfiy: Deletes `fixUnwindMismatches` function. Running this
function on the new instruction causes crashes, and the new version
will be added in a later CL, whose contents will be completely
different. So deleting the whole function will make the diff easier to
read.
- Reenables all disabled tests in exception.ll and eh-lsda.ll and a
single basic test in cfg-stackify-eh.ll.
- Updates existing tests to use the new assembly format. And deletes
`br_on_exn` instructions from the tests and FileCheck lines.
Reviewed By: dschuff, tlively
Differential Revision: https://reviews.llvm.org/D94040
A struct in C passed by value did not get debug information. Such values are currently
lowered to a Wasm local even in -O0 (not to an alloca like on other archs), which becomes
a Target Index operand (TI_LOCAL). The DWARF writing code was not emitting locations
in for TI's specifically if the location is a single range (not a list).
In addition, the ExplicitLocals pass which removes the ARGUMENT pseudo instructions did
not update the associated DBG_VALUEs, and couldn't even find these values since the code
assumed such instructions are adjacent, which is not the case here.
Also fixed asm printing of TIs needed by a test.
Differential Revision: https://reviews.llvm.org/D94140
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
As proposed in https://github.com/WebAssembly/simd/pull/380. This commit makes
the new instructions available only via clang builtins and LLVM intrinsics to
make their use opt-in while they are still being evaluated for inclusion in the
SIMD proposal.
Depends on D93771.
Differential Revision: https://reviews.llvm.org/D93775
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
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
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
This adds missing `select` instruction support and block return type
support for reference types. Also refactors WebAssemblyInstrRef.td and
rearranges tests in reference-types.s. Tests don't include `exnref`
types, because we currently don't support `exnref` for `ref.null` and
the type will be removed soon anyway.
Reviewed By: tlively, sbc100, wingo
Differential Revision: https://reviews.llvm.org/D92359
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
When we produce an YAML output, we also print leading zeroes currently.
An output might look like this:
```
- Name: .dynsym
Type: SHT_DYNSYM
Address: 0x0000000000001000
EntSize: 0x0000000000000018
```
There are probably no reason to print leading zeroes.
It just makes harder to read values. This patch stops printing them.
The output becomes like:
```
- Name: .dynsym
Type: SHT_DYNSYM
Address: 0x1000
EntSize: 0x18
```
This affects obj2yaml mostly, but also dsymutil and llvm-xray tools output.
Differential revision: https://reviews.llvm.org/D90930
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
This patch adds a new "heap type" operand kind to the WebAssembly MC
layer, used by ref.null. Currently the possible values are "extern" and
"func"; when typed function references come, though, this operand may be
a type index.
Note that the "heap type" production is still known as "refedtype" in
the draft proposal; changing its name in the spec is
ongoing (https://github.com/WebAssembly/reference-types/issues/123).
The register form of ref.null is still untested.
Differential Revision: https://reviews.llvm.org/D90608
Also added general wasm64 DWARF test
Also added asserts for unsupported reloc combinations that triggered this bug.
Differential Revision: https://reviews.llvm.org/D90503
Yuta Saito