[WebAssembly][libObject] Avoid re-use of Section object during parsing

The re-use of this struct across iterations of the loop was causing
fields (specifically Name) to be incorrectly shared between

[WebAssembly][libObject] Avoid re-use of Section object during parsing

The re-use of this struct across iterations of the loop was causing
fields (specifically Name) to be incorrectly shared between multiple
sections.

Differential Revision: https://reviews.llvm.org/D108984

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[WebAssembly] Support R_WASM_MEMORY_ADDR_TLS_SLEB64 for wasm64

Also fixed TLS tests swapping addr & value in store op
Differential Revision: https://reviews.llvm.org/D106096

[WebAssembly] Make tag attribute's encoding uint8

This changes the encoding of the `attribute` field, which currently only
contains the value `0` denoting this tag is for an exception, from
`varuint

[WebAssembly] Make tag attribute's encoding uint8

This changes the encoding of the `attribute` field, which currently only
contains the value `0` denoting this tag is for an exception, from
`varuint32` to `uint8`. This field is effectively unused at the moment
and reserved for future use, and it is not likely to need `varuint32`
even in future.
See https://github.com/WebAssembly/exception-handling/pull/162.

This does not change any encoded binaries because `0` is encoded in the
same way both in `varuint32` and `uint8`.

Reviewed By: tlively

Differential Revision: https://reviews.llvm.org/D104571

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[WebAssembly] Rename event to tag

We recently decided to change 'event' to 'tag', and 'event section' to
'tag section', out of the rationale that the section contains a
generalized tag that referenc

[WebAssembly] Rename event to tag

We recently decided to change 'event' to 'tag', and 'event section' to
'tag section', out of the rationale that the section contains a
generalized tag that references a type, which may be used for something
other than exceptions, and the name 'event' can be confusing in the web
context.

See
- https://github.com/WebAssembly/exception-handling/issues/159#issuecomment-857910130
- https://github.com/WebAssembly/exception-handling/pull/161

Reviewed By: tlively

Differential Revision: https://reviews.llvm.org/D104423

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[WebAssembly] Fix PIC/GOT codegen for wasm64

__table_base is know 64-bit, since in LLVM it represents a function pointer offset
__table_base32 is a copy in wasm32 for use in elem init expr, since no

[WebAssembly] Fix PIC/GOT codegen for wasm64

__table_base is know 64-bit, since in LLVM it represents a function pointer offset
__table_base32 is a copy in wasm32 for use in elem init expr, since no truncation may be used there.
New reloc R_WASM_TABLE_INDEX_REL_SLEB64 added

Differential Revision: https://reviews.llvm.org/D101784

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[lld][WebAssembly] Allow data symbols to extend past end of segment

This fixes a bug with string merging with string symbols that contain
NULLs, as is the case in the `merge-string.s` test.

The bug

[lld][WebAssembly] Allow data symbols to extend past end of segment

This fixes a bug with string merging with string symbols that contain
NULLs, as is the case in the `merge-string.s` test.

The bug only showed when we run with `--relocatable` and then try read
the resulting object back in. In this case we would end up with string
symbols that extend past the end of the segment in which they live.

The problem comes from the fact that sections which are flagged as
string mergable assume that all strings are NULL terminated. The
merging algorithm will drop trailing chars that follow a NULL since they
are essentially unreachable. However, the "size" attribute (in the
symbol table) of such a truncated symbol is not updated resulting a
symbol size that can overlap the end of the segment.

I verified that this can happen in ELF too given the right conditions
and the its harmless enough. In practice Strings that contain embedded
null should not be part of a mergable section.

Differential Revision: https://reviews.llvm.org/D102281

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Reland: "[lld][WebAssembly] Initial support merging string data"

This change was originally landed in: 5000a1b4b9edeb9e994f2a5b36da8d48599bea49
It was reverted in: 061e071d8c9b98526f35cad55a918a4f16

Reland: "[lld][WebAssembly] Initial support merging string data"

This change was originally landed in: 5000a1b4b9edeb9e994f2a5b36da8d48599bea49
It was reverted in: 061e071d8c9b98526f35cad55a918a4f1615afd4

This change adds support for a new WASM_SEG_FLAG_STRINGS flag in
the object format which works in a similar fashion to SHF_STRINGS
in the ELF world.

Unlike the ELF linker this support is currently limited:
- No support for SHF_MERGE (non-string merging)
- Always do full tail merging ("lo" can be merged with "hello")
- Only support single byte strings (p2align 0)

Like the ELF linker merging is only performed at `-O1` and above.

This fixes part of https://bugs.llvm.org/show_bug.cgi?id=48828,
although crucially it doesn't not currently support debug sections
because they are not represented by data segments (they are custom
sections)

Differential Revision: https://reviews.llvm.org/D97657

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Revert "[lld][WebAssembly] Initial support merging string data"

This reverts commit 5000a1b4b9edeb9e994f2a5b36da8d48599bea49.
Breaks tests, see https://reviews.llvm.org/D97657#2749151

Easily repros

Revert "[lld][WebAssembly] Initial support merging string data"

This reverts commit 5000a1b4b9edeb9e994f2a5b36da8d48599bea49.
Breaks tests, see https://reviews.llvm.org/D97657#2749151

Easily repros locally with `ninja check-llvm-mc-webassembly`.

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[lld][WebAssembly] Initial support merging string data

This change adds support for a new WASM_SEG_FLAG_STRINGS flag in
the object format which works in a similar fashion to SHF_STRINGS
in the ELF w

[lld][WebAssembly] Initial support merging string data

This change adds support for a new WASM_SEG_FLAG_STRINGS flag in
the object format which works in a similar fashion to SHF_STRINGS
in the ELF world.

Unlike the ELF linker this support is currently limited:
- No support for SHF_MERGE (non-string merging)
- Always do full tail merging ("lo" can be merged with "hello")
- Only support single byte strings (p2align 0)

Like the ELF linker merging is only performed at `-O1` and above.

This fixes part of https://bugs.llvm.org/show_bug.cgi?id=48828,
although crucially it doesn't not currently support debug sections
because they are not represented by data segments (they are custom
sections)

Differential Revision: https://reviews.llvm.org/D97657

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[lld][WebAssembly] Do not merge comdat data segments

When running in relocatable mode any input data segments that are part
of a comdat group should not be merged with other segments of the same
nam

[lld][WebAssembly] Do not merge comdat data segments

When running in relocatable mode any input data segments that are part
of a comdat group should not be merged with other segments of the same
name. This is because the final linker needs to keep the separate so
they can be included/excluded individually.

Often this is not a problem since normally only one section with a given
name `foo` ends up in the output object file. However, the problem
occurs when one input contains `foo` which part of a comdat and another
object contains a local symbol `foo` we were attempting to merge them.

This behaviour matches (I believe) that of the ELF linker. See
`LinkerScript.cpp:addInputSec`.

Fixes: https://github.com/emscripten-core/emscripten/issues/9726

Differential Revision: https://reviews.llvm.org/D101703

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[WebAssembly] Encode numbers in ULEB128 in event section

The number of events and the type index should be encoded in ULEB128,
but they were incorrctly encoded in LEB128. The smallest number with
wh

[WebAssembly] Encode numbers in ULEB128 in event section

The number of events and the type index should be encoded in ULEB128,
but they were incorrctly encoded in LEB128. The smallest number with
which its LEB128 and ULEB128 encodings are different is 64.
There's no way we can generate 64 events in the C++ toolchain
implementation so we can't test that, but the attached test tests when
the type index is 64.

Reviewed By: dschuff

Differential Revision: https://reviews.llvm.org/D99627

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[WebAssembly] Rename WasmLimits::Initial to ::Minimum. NFC.

This patch renames the "Initial" member of WasmLimits to the name used
in the spec, "Minimum".

In the core WebAssembly specification, th

[WebAssembly] Rename WasmLimits::Initial to ::Minimum. NFC.

This patch renames the "Initial" member of WasmLimits to the name used
in the spec, "Minimum".

In the core WebAssembly specification, the Limits data type has one
required "min" member and one optional "max" member, indicating the
minimum required size of the corresponding table or memory, and the
maximum size, if any.

Although the WebAssembly spec does instantiate locally-defined tables
and memories with the initial size being equal to the minimum size, it
can't impose such a requirement for imports. It doesn't make sense to
require an initial size for a memory import, for example. The compiler
can only sensibly express the minimum and maximum sizes.

See
https://github.com/WebAssembly/js-types/blob/master/proposals/js-types/Overview.md#naming-of-size-limits
for a related discussion that agrees that the right name of "initial" is
"minimum" when querying the type of a table or memory from JavaScript.
(Of course it still makes sense for JS to speak in terms of an initial
size when it explicitly instantiates memories and tables.)

Differential Revision: https://reviews.llvm.org/D99186

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[WebAssembly] Add new relocation for location relative data

This `R_WASM_MEMORY_ADDR_SELFREL_I32` relocation represents an offset
between its relocating address and the symbol address. It's very sim

[WebAssembly] Add new relocation for location relative data

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

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[WebAssembly][yaml2obj][obj2yaml] Elem sections for nonzero tables

With reference types, tables can have non-zero table numbers. This
commit adds support for element sections against these tables.

[WebAssembly][yaml2obj][obj2yaml] Elem sections for nonzero tables

With reference types, tables can have non-zero table numbers. This
commit adds support for element sections against these tables.

Differential Revision: https://reviews.llvm.org/D97923

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[Object][WebAssembly] Update format of error messages

Error message should start with lowercase in accordance with
https://llvm.org/docs/CodingStandards.html#error-and-warning-messages

Differential

[Object][WebAssembly] Update format of error messages

Error message should start with lowercase in accordance with
https://llvm.org/docs/CodingStandards.html#error-and-warning-messages

Differential Revision: https://reviews.llvm.org/D95239

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[WebAssembly] Test that invalid symbol/relocation types generate errors

See https://bugs.llvm.org/show_bug.cgi?id=48827

Differential Revision: https://reviews.llvm.org/D95163

[WebAssembly] Change prefix on data segment flags to WASM_DATA_SEGMENT

Element sections will also need flags, so we shouldn't squat the
WASM_SEGMENT namespace.

Depends on D90948.

Differential Revi

[WebAssembly] Change prefix on data segment flags to WASM_DATA_SEGMENT

Element sections will also need flags, so we shouldn't squat the
WASM_SEGMENT namespace.

Depends on D90948.

Differential Revision: https://reviews.llvm.org/D92315

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[lld][WebAssembly] Add support for handling table symbols

This commit adds table symbol support in a partial way, while still
including some special cases for the __indirect_function_table symbol.
N

[lld][WebAssembly] Add support for handling table symbols

This commit adds table symbol support in a partial way, while still
including some special cases for the __indirect_function_table symbol.
No change in tests.

Differential Revision: https://reviews.llvm.org/D94075

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[WebAssembly] Add support for named data sections in wasm binaries

Followup to https://reviews.llvm.org/D91769 which added support
for names globals.

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

[WebAssembly] Add support for named data sections in wasm binaries

Followup to https://reviews.llvm.org/D91769 which added support
for names globals.

Differential Revision: https://reviews.llvm.org/D92909

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[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 unnam

[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

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[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 Revi

[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

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[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
e

[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

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[WebAssembly] Add support for named globals in the object format.

Differential Revision: https://reviews.llvm.org/D91769

[WebAssembly] Fix parsing of linking section for named global imports

Differential Revision: https://reviews.llvm.org/D91635

[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/D

[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

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