[AsmPrinter][ELF] Support profile-guided section prefix for jump tables' (read-only) data sections (#122215)

https://github.com/llvm/llvm-project/pull/122183 adds a codegen pass to
infer machine jum

[AsmPrinter][ELF] Support profile-guided section prefix for jump tables' (read-only) data sections (#122215)

https://github.com/llvm/llvm-project/pull/122183 adds a codegen pass to
infer machine jump table entry's hotness from the MBB hotness. This is a
follow-up PR to produce `.hot` and or `.unlikely` section prefix for
jump table's (read-only) data sections in the relocatable `.o` files.

When this patch is enabled, linker will see {`.rodata`, `.rodata.hot`,
`.rodata.unlikely`} in input sections. It can map `.rodata.hot` and
`.rodata` in the input sections to `.rodata.hot` in the executable, and
map `.rodata.unlikely` into `.rodata` with a pending extension to
`--keep-text-section-prefix` like
https://github.com/llvm/llvm-project/commit/059e7cbb66a30ce35f3ee43197eed1a106b50c5b,
or with a linker script.

1. To partition hot and jump tables, the AsmPrinter pass slices a function's jump table indices into two groups, one for hot and the other for cold jump tables. It then emits hot jump tables into a `.hot`-prefixed data section and cold ones into a `.unlikely`-prefixed data section, retaining the relative order of `LJT<N>` labels within each group.

2. [ELF only] To have data sections with _dynamic_ names (e.g., `.rodata.hot[.func]`), we implement
`TargetLoweringObjectFile::getSectionForJumpTable` method that accepts a `MachineJumpTableEntry` parameter, and update `selectELFSectionForGlobal` to generate `.hot` or `.unlikely` based on
MJTE's hotness.
- The dynamic JT section name doesn't depend on `-ffunction-section=true` or `-funique-section-names=true`, even though it leverages the similar underlying mechanism to have a MCSection with on-demand name as `-ffunction-section` does.

3. The new code path is off by default.
- Typically, `TargetOptions` conveys clang or LLVM tools' options to code generation passes. To follow the pattern, add option `EnableStaticDataPartitioning` bit in `TargetOptions` and make it
readable through `TargetMachine`.
- To enable the new code path in tools like `llc`, `partition-static-data-sections` option is introduced in
`CodeGen/CommandFlags.h/cpp`.
- A subsequent patch
([draft](https://github.com/llvm/llvm-project/commit/8f36a1374365862b3ca9be5615dd38f02a318c45)) will add a clang option to enable the new code path.

---------

Co-authored-by: Ellis Hoag <ellis.sparky.hoag@gmail.com>

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[NFC][CodeGen] Fix typos in code comments. (#124382)

This fixes typos in `calcUniqueIDUpdateFlagsAndSize` function.

[TLOF][NFC] Make emitLinkerDirectives virtual and public. (#123773)

Today, emitLinkerDirectives is private to TLOFCOFF-- it isolates parsing
and processing of the linker options. Similar processing

[TLOF][NFC] Make emitLinkerDirectives virtual and public. (#123773)

Today, emitLinkerDirectives is private to TLOFCOFF-- it isolates parsing
and processing of the linker options. Similar processing is also done by
other TLOFs inline within emitModuleMetadata. This patch promotes
emitLinkerDirectives to a virtual (public) method so that this handling
is similarly isolated in the other TLOFs.

This also enables downstream targets to override just this handling
instead of the whole of emitModuleMetadata.

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[clang] Implement #pragma clang section on COFF targets (#112714)

This patch implements the directive #pragma clang section on COFF targets
with the exact same features available on ELF and Mach-O.

[PAC][ELF][AArch64] Support signed personality function pointer (#119361)

Re-apply #113148 after revert in #119331

If function pointer signing is enabled, sign personality function
pointer store

[PAC][ELF][AArch64] Support signed personality function pointer (#119361)

Re-apply #113148 after revert in #119331

If function pointer signing is enabled, sign personality function
pointer stored in `.DW.ref.__gxx_personality_v0` section with IA key,
0x7EAD = `ptrauth_string_discriminator("personality")` constant
discriminator and address diversity enabled.

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Revert "[PAC][ELF][AArch64] Support signed personality function pointer" (#119331)

Reverts llvm/llvm-project#113148

See buildbot failure
https://lab.llvm.org/buildbot/#/builders/190/builds/11048

[PAC][ELF][AArch64] Support signed personality function pointer (#113148)

If function pointer signing is enabled, sign personality function
pointer stored in `.DW.ref.__gxx_personality_v0` section

[PAC][ELF][AArch64] Support signed personality function pointer (#113148)

If function pointer signing is enabled, sign personality function
pointer stored in `.DW.ref.__gxx_personality_v0` section with IA key,
0x7EAD = `ptrauth_string_discriminator("personality")` constant
discriminator and address diversity enabled.

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[Coverage][WebAssembly] Add initial support for WebAssembly/WASI (#111332)

Currently, WebAssembly/WASI target does not provide direct support for
code coverage.
This patch set fixes several issues

[Coverage][WebAssembly] Add initial support for WebAssembly/WASI (#111332)

Currently, WebAssembly/WASI target does not provide direct support for
code coverage.
This patch set fixes several issues to unlock the feature. The main
changes are:

1. Port `compiler-rt/lib/profile` to WebAssembly/WASI.
2. Adjust profile metadata sections for Wasm object file format.
- [CodeGen] Emit `__llvm_covmap` and `__llvm_covfun` as custom sections
instead of data segments.
- [lld] Align the interval space of custom sections at link time.
- [llvm-cov] Copy misaligned custom section data if the start address is
not aligned.
- [llvm-cov] Read `__llvm_prf_names` from data segments
3. [clang] Link with profile runtime libraries if requested

See each commit message for more details and rationale.
This is part of the effort to add code coverage support in Wasm target
of Swift toolchain.

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CodeGen: Avoid some references to MachineFunction's getMMI (#99652)

MachineFunction's probably should not include a backreference to
the owning MachineModuleInfo. Most of these references were used

CodeGen: Avoid some references to MachineFunction's getMMI (#99652)

MachineFunction's probably should not include a backreference to
the owning MachineModuleInfo. Most of these references were used
just to query the MCContext, which MachineFunction already directly
stores. Other contexts are using it to query the LLVMContext, which
can already be accessed through the IR function reference.

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[MC] Move Mach-O specific getAtom and isSectionAtomizableBySymbols to Mach-O files

and devirtualize isSectionAtomizableBySymbols.

[IR] Add getDataLayout() helpers to Function and GlobalValue (#96919)

Similar to https://github.com/llvm/llvm-project/pull/96902, this adds
`getDataLayout()` helpers to Function and GlobalValue, re

[IR] Add getDataLayout() helpers to Function and GlobalValue (#96919)

Similar to https://github.com/llvm/llvm-project/pull/96902, this adds
`getDataLayout()` helpers to Function and GlobalValue, replacing the
current `getParent()->getDataLayout()` pattern.

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[MC] Change Subsection parameters from const MCExpr * to uint32_t

Follow-up to 05ba5c0648ae5e80d5afce270495bf3b1eef9af4. uint32_t is
preferred over const MCExpr * in the section stack uses because i

[MC] Change Subsection parameters from const MCExpr * to uint32_t

Follow-up to 05ba5c0648ae5e80d5afce270495bf3b1eef9af4. uint32_t is
preferred over const MCExpr * in the section stack uses because it
should only be evaluated once. Change the paramter type to match.

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[MC] Remove SectionKind from MCSection (#96067)

There are only three actual uses of the section kind in MCSection:
isText(), XCOFF, and WebAssembly. Store isText() in the MCSection, and
store othe

[MC] Remove SectionKind from MCSection (#96067)

There are only three actual uses of the section kind in MCSection:
isText(), XCOFF, and WebAssembly. Store isText() in the MCSection, and
store other info in the actual section variants where required.

ELF and COFF flags also encode all relevant information, so for these
two section variants, remove the SectionKind parameter entirely.

This allows to remove the string switch (which is unnecessary and
inaccurate) from createELFSectionImpl. This was introduced in
[D133456](https://reviews.llvm.org/D133456), but apparently, it was
never hit for non-writable sections anyway and the resulting kind was
never used.

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[CodeGen] Assign SHT_LLVM_LTO to .llvm.lto section (#92856)

This follows up to SHT_LLVM_LTO (https://reviews.llvm.org/D153215) and
resolves the comment of the FatLTO patch
https://reviews.llvm.org

[CodeGen] Assign SHT_LLVM_LTO to .llvm.lto section (#92856)

This follows up to SHT_LLVM_LTO (https://reviews.llvm.org/D153215) and
resolves the comment of the FatLTO patch
https://reviews.llvm.org/D146776#4430626

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MIPS: Use pcrel|sdata4 for eh_frame (#91291)

Gas uses encoding DW_EH_PE_absptr for PIC, and gnu ld converts it to
DW_EH_PE_sdata4|DW_EH_PE_pcrel.
LLD doesn't have this workarounding, thus complain

MIPS: Use pcrel|sdata4 for eh_frame (#91291)

Gas uses encoding DW_EH_PE_absptr for PIC, and gnu ld converts it to
DW_EH_PE_sdata4|DW_EH_PE_pcrel.
LLD doesn't have this workarounding, thus complains
```
relocation R_MIPS_32 cannot be used against local symbol; recompile with -fPIC
relocation R_MIPS_64 cannot be used against local symbol; recompile with -fPIC
```

So, let's generates asm/obj files with `DW_EH_PE_sdata4|DW_EH_PE_pcrel`
encoding. In fact, GNU ld supports such OBJs well.

For N64, maybe we should use sdata8, while GNU ld doesn't support it
well, and in fact sdata4 is enough now. So we just ignore the `Large`
for `MCObjectFileInfo::initELFMCObjectFileInfo`. Maybe we should switch
back to sdata8 once GNU LD supports it well.

Fixes: #58377.

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[Analysis, CodeGen, DebugInfo] Use StringRef::operator== instead of StringRef::equals (NFC) (#91304)

I'm planning to remove StringRef::equals in favor of
StringRef::operator==.

- StringRef::oper

[Analysis, CodeGen, DebugInfo] Use StringRef::operator== instead of StringRef::equals (NFC) (#91304)

I'm planning to remove StringRef::equals in favor of
StringRef::operator==.

- StringRef::operator==/!= outnumber StringRef::equals by a factor of
53 under llvm/ in terms of their usage.

- The elimination of StringRef::equals brings StringRef closer to
std::string_view, which has operator== but not equals.

- S == "foo" is more readable than S.equals("foo"), especially for
!Long.Expression.equals("str") vs Long.Expression != "str".

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[Clang] -fseparate-named-sections option (#91028)

When set, the compiler will use separate unique sections for global
symbols in named special sections (e.g. symbols that are annotated with
__attr

[Clang] -fseparate-named-sections option (#91028)

When set, the compiler will use separate unique sections for global
symbols in named special sections (e.g. symbols that are annotated with
__attribute__((section(...)))). Doing so enables linker GC to collect
unused symbols without having to use a different section per-symbol.

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[clang][llvm] Remove "implicit-section-name" attribute (#87906)

D33412/D33413 introduced this to support a clang pragma to set section
names for a symbol depending on if it would be placed in
bss/

[clang][llvm] Remove "implicit-section-name" attribute (#87906)

D33412/D33413 introduced this to support a clang pragma to set section
names for a symbol depending on if it would be placed in
bss/data/rodata/text, which may not be known until the backend. However,
for text we know that only functions will go there, so just directly set
the section in clang instead of going through a completely separate
attribute.

Autoupgrade the "implicit-section-name" attribute to directly setting
the section on a Fuction.

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[AIX] Support per global code model. (#79202)

Exploit the per global code model attribute on AIX. On AIX we need to
update both the code sequence used to access the global (either 1 or 2
instructi

[AIX] Support per global code model. (#79202)

Exploit the per global code model attribute on AIX. On AIX we need to
update both the code sequence used to access the global (either 1 or 2
instructions for small and large code model respectively) and the
storage mapping class that we emit the toc entry.

---------

Co-authored-by: Amy Kwan <akwan0907@gmail.com>

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[PowerPC] Support local-dynamic TLS relocation on AIX (#66316)

Supports TLS local-dynamic on AIX, generates below sequence of code:

```
.tc foo[TC],foo[TL]@ld # Variable offset, ld relocation sp

[PowerPC] Support local-dynamic TLS relocation on AIX (#66316)

Supports TLS local-dynamic on AIX, generates below sequence of code:

```
.tc foo[TC],foo[TL]@ld # Variable offset, ld relocation specifier
.tc mh[TC],mh[TC]@ml # Module handle for the caller
lwz 3,mh[TC]\(2\) $$ For 64-bit: ld 3,mh[TC]\(2\)
bla .__tls_get_mod # Modifies r0,r3,r4,r5,r11,lr,cr0
#r3 = &TLS for module
lwz 4,foo[TC]\(2\) $$ For 64-bit: ld 4,foo[TC]\(2\)
add 5,3,4 # Compute &foo
.rename mh[TC], "\_$TLSML" # Symbol for the module handle must have the name "_$TLSML"
```

---------

Co-authored-by: tingwang <tingwang@tingwangs-MBP.lan>
Co-authored-by: tingwang <tingwang@tingwangs-MacBook-Pro.local>

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[WebAssembly] Add segment RETAIN flag to support private retained data (#81539)

In WebAssembly, we have `WASM_SYMBOL_NO_STRIP` symbol flag to mark the
referenced content as retained. However, the f

[WebAssembly] Add segment RETAIN flag to support private retained data (#81539)

In WebAssembly, we have `WASM_SYMBOL_NO_STRIP` symbol flag to mark the
referenced content as retained. However, the flag is not enough to
express retained data that is not referenced by any symbol. This patch
adds a new segment flag`WASM_SEG_FLAG_RETAIN` to support "private"
linkage data that is retained by llvm.used.

This kind of data that is not referenced but must be retained is usually
used with encapsulation symbols (__start/__stop). Swift runtime uses
this technique and depends on the fact "all metadata sections in live
objects are retained", which was not guaranteed with `--gc-sections`
before this patch.

This is a revised version of https://reviews.llvm.org/D126950 (has been
reverted) based on @MaskRay's comments

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[X86] Use ".lrodata" prefix for large mergeable constants (#81900)

Otherwise with a small enough large-data-threshold, we can get .rodata.*
sections marked large, making .rodata large in the final

[X86] Use ".lrodata" prefix for large mergeable constants (#81900)

Otherwise with a small enough large-data-threshold, we can get .rodata.*
sections marked large, making .rodata large in the final binary.

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[llvm] Use StringRef::starts_with (NFC)

[AIX] [XCOFF] Add support for common and local common symbols in the TOC (#79530)

This patch adds support for common and local symbols in the TOC for AIX.
Note that we need to update isVirtualSecti

[AIX] [XCOFF] Add support for common and local common symbols in the TOC (#79530)

This patch adds support for common and local symbols in the TOC for AIX.
Note that we need to update isVirtualSection so as a common symbol in
TOC will have the symbol type XTY_CM and will be initialized when placed
in the TOC so sections with this type are no longer virtual.

---------

Co-authored-by: Zaara Syeda <syzaara@ca.ibm.com>

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[Coverage] Mark coverage sections as metadata sections on COFF. (#76834)

Mark `.lcovmap$M`, `.lcovfun$M`, `.lcovd` and `.lcovn` as metadata
sections on COFF so they are not loaded into memory.