[wasm-ld] Define a `__heap_end` symbol marking the end of allocated memory.

Define a `__heap_end` symbol that marks the end of the memory region
that starts at `__heap_base`. This will allow malloc

[wasm-ld] Define a `__heap_end` symbol marking the end of allocated memory.

Define a `__heap_end` symbol that marks the end of the memory region
that starts at `__heap_base`. This will allow malloc implementations to
know how much memory they can use at `__heap_base` even if someone has
done a `memory.grow` before they can initialize their state.

Differential Revision: https://reviews.llvm.org/D136110

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[lld][WebAssembly] Don't apply data relocations at static constructor time

Instead, export `__wasm_apply_data_relocs` and `__wasm_call_ctors`
separately.

This is required since user code in a share

[lld][WebAssembly] Don't apply data relocations at static constructor time

Instead, export `__wasm_apply_data_relocs` and `__wasm_call_ctors`
separately.

This is required since user code in a shared library (such as static
constructors) should not be run until relocations have been applied to
all loaded libraries.

See: https://github.com/emscripten-core/emscripten/issues/17295

Differential Revision: https://reviews.llvm.org/D128515

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Don't use Optional::hasValue (NFC)

[lld] Use value_or instead of getValueOr (NFC)

[lld][WebAssemlby] Check for command line flags with missing arguments

I'm really not sure how this was overlooked when we first ported lld
to Wasm. The upstream code in the ELF backend has these t

[lld][WebAssemlby] Check for command line flags with missing arguments

I'm really not sure how this was overlooked when we first ported lld
to Wasm. The upstream code in the ELF backend has these two lines but
for some reason they never make it into the Wasm version.

Differential Revision: https://reviews.llvm.org/D126497

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[lld] Remove support for legacy pass manager

This removes options for performing LTO with the legacy pass
manager in LLD. Options that explicitly enable the new pass manager
are retained as no-ops.

[lld] Remove support for legacy pass manager

This removes options for performing LTO with the legacy pass
manager in LLD. Options that explicitly enable the new pass manager
are retained as no-ops.

Differential Revision: https://reviews.llvm.org/D123219

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[cmake] Remove LLVM_ENABLE_NEW_PASS_MANAGER cmake option

Or rather, error out if it is set to something other than ON. This
removes the ability to enable the legacy pass manager by default,
but does

[cmake] Remove LLVM_ENABLE_NEW_PASS_MANAGER cmake option

Or rather, error out if it is set to something other than ON. This
removes the ability to enable the legacy pass manager by default,
but does not remove the ability to explicitly enable it through
various flags like -flegacy-pass-manager or -enable-new-pm=0.

I checked, and our test suite definitely doesn't pass with
LLVM_ENABLE_NEW_PASS_MANAGER=OFF anymore.

Differential Revision: https://reviews.llvm.org/D123126

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[lld][WebAssembly] Add --unresolved-symbols=import-dynamic

This is a new mode for handling unresolved symbols that allows all
symbols to be imported in the same that they would be in the case of
`-f

[lld][WebAssembly] Add --unresolved-symbols=import-dynamic

This is a new mode for handling unresolved symbols that allows all
symbols to be imported in the same that they would be in the case of
`-fpie` or `-shared`, but generting an otherwise fixed/non-relocatable
binary.

Code linked in this way should still be compiled with `-fPIC` so that
data symbols can be resolved via imports.

This essentially allows the building of static binaries that have
dynamic imports. See:
https://github.com/emscripten-core/emscripten/issues/12682

As with other uses of the experimental dynamic linking ABI, this
behaviour will produce a warning unless run with `--experimental-pic`.

Differential Revision: https://reviews.llvm.org/D91577

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[lld][WebAssemlby] Warn on unknown -z flags

This code mirrors that in lld/ELF/Driver.cpp, as does the new test code.

Differential Revision: https://reviews.llvm.org/D119888

[lld][WebAssembly] Remove redundant config setting

Unresolved symbols are not currently reported when building with
`-shared` or `-pie` so setting unresolvedSymbols doesn't have any
effect.

Differe

[lld][WebAssembly] Remove redundant config setting

Unresolved symbols are not currently reported when building with
`-shared` or `-pie` so setting unresolvedSymbols doesn't have any
effect.

Differential Revision: https://reviews.llvm.org/D117737

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Re-land [LLD] Remove global state in lldCommon

Move all variables at file-scope or function-static-scope into a hosting structure (lld::CommonLinkerContext) that lives at lldMain()-scope. Drivers wi

Re-land [LLD] Remove global state in lldCommon

Move all variables at file-scope or function-static-scope into a hosting structure (lld::CommonLinkerContext) that lives at lldMain()-scope. Drivers will inherit from this structure and add their own global state, in the same way as for the existing COFFLinkerContext.

See discussion in https://lists.llvm.org/pipermail/llvm-dev/2021-June/151184.html

The previous land f860fe362282ed69b9d4503a20e5d20b9a041189 caused issues in https://lab.llvm.org/buildbot/#/builders/123/builds/8383, fixed by 22ee510dac9440a74b2e5b3fe3ff13ccdbf55af3.

Differential Revision: https://reviews.llvm.org/D108850

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Revert [LLD] Remove global state in lldCommon

It seems to be causing issues on https://lab.llvm.org/buildbot/#/builders/123/builds/8383

[LLD] Remove global state in lldCommon

Move all variables at file-scope or function-static-scope into a hosting structure (lld::CommonLinkerContext) that lives at lldMain()-scope. Drivers will inher

[LLD] Remove global state in lldCommon

Move all variables at file-scope or function-static-scope into a hosting structure (lld::CommonLinkerContext) that lives at lldMain()-scope. Drivers will inherit from this structure and add their own global state, in the same way as for the existing COFFLinkerContext.

See discussion in https://lists.llvm.org/pipermail/llvm-dev/2021-June/151184.html

Differential Revision: https://reviews.llvm.org/D108850

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[NFC] Inclusive language: Remove instances of master in URLs

[NFC] This patch fixes URLs containing "master". Old URLs were either broken or
redirecting to the new URL.

Reviewed By: #libc, ldionne,

[NFC] Inclusive language: Remove instances of master in URLs

[NFC] This patch fixes URLs containing "master". Old URLs were either broken or
redirecting to the new URL.

Reviewed By: #libc, ldionne, mehdi_amini

Differential Revision: https://reviews.llvm.org/D113186

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[lld] Rename addCombinedLTOObjects to match ELF driver. NFC

This function was renamed in https://reviews.llvm.org/D62291.
The new name seems more accurate and also its good to maintain
some consiste

[lld] Rename addCombinedLTOObjects to match ELF driver. NFC

This function was renamed in https://reviews.llvm.org/D62291.
The new name seems more accurate and also its good to maintain
some consistency between these methods in the different drivers.

Differential Revision: https://reviews.llvm.org/D112719

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fix comment typos to cycle bots

[lld][WebAssembly] Create optional internal symbols only after LTO object as been added

This is important for the cases where new symbols can be introduced
during LTO. Specifically this happens fo

[lld][WebAssembly] Create optional internal symbols only after LTO object as been added

This is important for the cases where new symbols can be introduced
during LTO. Specifically this happens for during TLS-lowering where
references to `__tls_base` can be introduced.

Fixes: https://github.com/emscripten-core/emscripten/issues/12489

Differential Revision: https://reviews.llvm.org/D111171

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[lld][WebAssembly] Fix crash on un-used __tls_base symbol

In the case that TLS is used in the single-threaded program, and
therefore effectively lowered away, we still optionally create a
`__tls_bas

[lld][WebAssembly] Fix crash on un-used __tls_base symbol

In the case that TLS is used in the single-threaded program, and
therefore effectively lowered away, we still optionally create a
`__tls_base` symbols, but the code for setting it was assuming it was
always created.

Differential Revision: https://reviews.llvm.org/D109518

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[WebAssembly] Fixed LLD generation of 64-bit __wasm_apply_data_relocs

Differential Revision: https://reviews.llvm.org/D105863

[OptTable] Rename PrintHelp to printHelp

To be consistent with other member functions and match the coding standard.

[lld][WebAssembly] Add new `--import-undefined` option

This change revisits https://reviews.llvm.org/D79248 which originally
added support for the --unresolved-symbols flag.

At the time I thought i

[lld][WebAssembly] Add new `--import-undefined` option

This change revisits https://reviews.llvm.org/D79248 which originally
added support for the --unresolved-symbols flag.

At the time I thought it would make sense to add a third option to this
flag called `import-functions` but it turns out (as was suspects by on
the reviewers IIRC) that this option can be authoganal.

Instead I've added a new option called `--import-undefined` that only
operates on symbols that can be imported (for example, function symbols
can always be imported as opposed to data symbols we can only be
imported when compiling with PIC).

This option gives us the full expresivitiy that emscripten needs to be
able allow reporting of undefined data symbols as well as the option to
disable that.

This change does remove the `--unresolved-symbols=import-functions`
option, which is been in the codebase now for about a year but I would
be extremely surprised if anyone was using it.

Differential Revision: https://reviews.llvm.org/D103290

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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] Enable string tail merging in debug sections

This is a followup to https://reviews.llvm.org/D97657 which
applied string tail merging to data segments.

Fixes: https://bugs.llvm.or

[lld][WebAssembly] Enable string tail merging in debug sections

This is a followup to https://reviews.llvm.org/D97657 which
applied string tail merging to data segments.

Fixes: https://bugs.llvm.org/show_bug.cgi?id=48828

Differential Revision: https://reviews.llvm.org/D102436

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[lld][WebAssembly] Refactor input chunk class hierarchy. NFC

The main motivation for this refactor is to remove the subclass
relationship between the InputSegment and MergeInputSegment and
Syntentic

[lld][WebAssembly] Refactor input chunk class hierarchy. NFC

The main motivation for this refactor is to remove the subclass
relationship between the InputSegment and MergeInputSegment and
SyntenticMergedInputSegment so that we can use the merging classes for
debug sections which are not data segments.

In the process of refactoring I also remove all the virtual functions
from the class hierarchy and try to reuse techniques used in the ELF
linker (see `lld/ELF/InputSections.h`).

Differential Revision: https://reviews.llvm.org/D102546

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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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