[Driver] Add -Wa, options -mmapsyms={default,implicit}

-Wa,-mmapsyms=implicit enables the alternative mapping symbol scheme
discussed at #99718.

While not conforming to the current aaelf64 ABI, the

[Driver] Add -Wa, options -mmapsyms={default,implicit}

-Wa,-mmapsyms=implicit enables the alternative mapping symbol scheme
discussed at #99718.

While not conforming to the current aaelf64 ABI, the option is
invaluable for those with full control over their toolchain, no reliance
on weird relocatable files, and a strong focus on minimizing both
relocatable and executable sizes.

The option is discouraged when portability of the relocatable objects is
a concern.
https://maskray.me/blog/2024-07-21-mapping-symbols-rethinking-for-efficiency
elaborates the risk.

Pull Request: https://github.com/llvm/llvm-project/pull/104542

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[Driver] Make CodeGenOptions name match MCTargetOptions names

* Initialize `X86RelaxRelocations`.
* Fix #96860 test to actually test -Wa,-msse2avx for non-x86.

[MC] Remove Darwin SDK/Version from ObjFileInfo (#103025)

There's only a single user (MCMachOStreamer), so it makes more sense to
move the version emission to the source of the data.

[MC] Migrate to new createAsmStreamer that avoids unused bool parameters

[MC] MCAsmStreamer: use MCTargetOptions

Some bool parameters duplicate MCTargetOptions and might cause
inconsistency/confusion.

[MC] Remove unused bool arguments from createMCObjectStreamer callers

[X86][MC,Driver] Support -msse2avx to encode SSE instruction with VEX prefix (#96860)

For GCC compatibility
https://gcc.gnu.org/onlinedocs/gcc-14.1.0/gcc/x86-Options.html.

[Driver] Add -Wa, options --crel and --allow-experimental-crel

The two options are discussed in a few comments around
https://github.com/llvm/llvm-project/pull/91280#issuecomment-2099344079

* -Wa,-

[Driver] Add -Wa, options --crel and --allow-experimental-crel

The two options are discussed in a few comments around
https://github.com/llvm/llvm-project/pull/91280#issuecomment-2099344079

* -Wa,--crel: error "-Wa,--allow-experimental-crel must be specified to use -Wa,--crel..."
* -Wa,--allow-experimental-crel: no-op
* -Wa,--crel,--allow-experimental-crel: enable CREL in the integrated assembler (#91280)

MIPS's little-endian n64 ABI messed up the `r_info` field in
relocations. While this could be fixed with CREL, my intention is to
avoid complication in assembler/linker. The implementation simply
doesn't allow CREL for MIPS.

Link: https://discourse.llvm.org/t/rfc-crel-a-compact-relocation-format-for-elf/77600

Pull Request: https://github.com/llvm/llvm-project/pull/97378

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[MC] Move AllowTemporaryLabels setting to MCContext::MCContext

Also delete `AllowTemporaryLabels = true` from MCContext::reset: when
llc supports -save-temp-labels in the next change, this assignmen

[MC] Move AllowTemporaryLabels setting to MCContext::MCContext

Also delete `AllowTemporaryLabels = true` from MCContext::reset: when
llc supports -save-temp-labels in the next change, this assignment
should be removed to support -compile-twice.

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[MC] Make UseAssemblerInfoForParsing mostly true

Commit 6c0665e22174d474050e85ca367424f6e02476be
(https://reviews.llvm.org/D45164) enabled certain constant expression
evaluation for `MCObjectStreame

[MC] Make UseAssemblerInfoForParsing mostly true

Commit 6c0665e22174d474050e85ca367424f6e02476be
(https://reviews.llvm.org/D45164) enabled certain constant expression
evaluation for `MCObjectStreamer` at parse time (e.g. `.if` directives,
see llvm/test/MC/AsmParser/assembler-expressions.s).

`getUseAssemblerInfoForParsing` was added to make `clang -c` handling
inline assembly similar to `MCAsmStreamer` (e.g. `llvm-mc -filetype=asm`),
where such expression folding (related to
`AttemptToFoldSymbolOffsetDifference`) is unavailable.

I believe this is overly conservative. We can make some parse-time
expression folding work for `clang -c` even if `clang -S` would still
report an error, a MCAsmStreamer issue (we cannot print `.if`
directives) that should not restrict the functionality of
MCObjectStreamer.

```
% cat b.cc
asm(R"(
.pushsection .text,"ax"
.globl _start; _start: ret
.if . -_start == 1
ret
.endif
.popsection
)");
% gcc -S b.cc && gcc -c b.cc
% clang -S -fno-integrated-as b.cc # succeeded

% clang -c b.cc # succeeded with this patch
% clang -S b.cc # still failed
<inline asm>:4:5: error: expected absolute expression
4 | .if . -_start == 1
| ^
1 error generated.
```

However, removing `getUseAssemblerInfoForParsing` would make
MCDwarfFrameEmitter::Emit (for .eh_frame FDE) slow (~4% compile time
regression for sqlite3.c amalgamation) due to expensive
`AttemptToFoldSymbolOffsetDifference`. For now, make
`UseAssemblerInfoForParsing` false in MCDwarfFrameEmitter::Emit.

Close #62520
Link: https://discourse.llvm.org/t/rfc-clang-assembly-object-equivalence-for-files-with-inline-assembly/78841

Pull Request: https://github.com/llvm/llvm-project/pull/91082

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Revert "[MC] Remove UseAssemblerInfoForParsing"

This reverts commit 03c53c69a367008da689f0d2940e2197eb4a955c.

This causes very large compile-time regressions in some cases,
e.g. sqlite3 at O0 regre

Revert "[MC] Remove UseAssemblerInfoForParsing"

This reverts commit 03c53c69a367008da689f0d2940e2197eb4a955c.

This causes very large compile-time regressions in some cases,
e.g. sqlite3 at O0 regresses by 5%.

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[MC] Remove UseAssemblerInfoForParsing

Commit 6c0665e22174d474050e85ca367424f6e02476be
(https://reviews.llvm.org/D45164) enabled certain constant expression
evaluation for `MCObjectStreamer` at pars

[MC] Remove UseAssemblerInfoForParsing

Commit 6c0665e22174d474050e85ca367424f6e02476be
(https://reviews.llvm.org/D45164) enabled certain constant expression
evaluation for `MCObjectStreamer` at parse time (e.g. `.if` directives,
see llvm/test/MC/AsmParser/assembler-expressions.s).

`getUseAssemblerInfoForParsing` was added to make `clang -c` handling
inline assembly similar to `MCAsmStreamer` (e.g. `llvm-mc -filetype=asm`),
where such expression folding (related to
`AttemptToFoldSymbolOffsetDifference`) is unavailable.

I believe this is overly conservative. We can make some parse-time
expression folding work for `clang -c` even if `clang -S` would still
report an error, a MCAsmStreamer issue (we cannot print `.if`
directives) that should not restrict the functionality of
MCObjectStreamer.

```
% cat b.cc
asm(R"(
.pushsection .text,"ax"
.globl _start; _start: ret
.if . -_start == 1
ret
.endif
.popsection
)");
% gcc -S b.cc && gcc -c b.cc
% clang -S -fno-integrated-as b.cc # succeeded

% clang -c b.cc # succeeded with this patch
% clang -S b.cc # still failed
<inline asm>:4:5: error: expected absolute expression
4 | .if . -_start == 1
| ^
1 error generated.
```

Close #62520
Link: https://discourse.llvm.org/t/rfc-clang-assembly-object-equivalence-for-files-with-inline-assembly/78841

Pull Request: https://github.com/llvm/llvm-project/pull/91082

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[cc1as] Respect -mrelax-all

So that `clang -c -mrelax-all a.s` sets MCRelaxAll and assembles JMP/JCC
to a near jump instead of silently ignoring `-mrelax-all`.

[MC] Move CompressDebugSections/RelaxELFRelocations from TargetOptions/MCAsmInfo to MCTargetOptions

The convention is for such MC-specific options to reside in
MCTargetOptions. However, CompressDebu

[MC] Move CompressDebugSections/RelaxELFRelocations from TargetOptions/MCAsmInfo to MCTargetOptions

The convention is for such MC-specific options to reside in
MCTargetOptions. However, CompressDebugSections/RelaxELFRelocations do
not follow the convention: `CompressDebugSections` is defined in both
TargetOptions and MCAsmInfo and there is forwarding complexity.

Move the option to MCTargetOptions and hereby simplify the code. Rename
the misleading RelaxELFRelocations to X86RelaxRelocations. llvm-mc
-relax-relocations and llc -x86-relax-relocations can now be unified.

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[clang][NFC] Annotate `cc1as_main.cpp` with `preferred_type`

This helps debuggers to display values in bit-fields in a more helpful way.

[Driver] Refactor to use llvm Option's new Visibility flags

This is a big refactor of the clang driver's option handling to use
the Visibility flags introduced in https://reviews.llvm.org/D157149.
T

[Driver] Refactor to use llvm Option's new Visibility flags

This is a big refactor of the clang driver's option handling to use
the Visibility flags introduced in https://reviews.llvm.org/D157149.
There are a few distinct parts, but they can't really be split into
separate commits and still be made to compile.

1. We split out some of the flags in ClangFlags to ClangVisibility.
Note that this does not include any subtractive flags.

2. We update the Flag definitions and OptIn/OptOut constructs in
Options.td by hand.

3. We introduce and use a script, update_options_td_flags, to ease
migration of flag definitions in Options.td, and we run that on
Options.td. I intend to remove this later, but I'm committing it so
that downstream forks can use the script to simplify merging.

4. We update calls to OptTable in the clang driver, cc1as, flang, and
clangd to use the visibility APIs instead of Include/Exclude flags.

5. We deprecate the Include/Exclude APIs and add a release note.

*if you are running into conflicts with this change:*

Note that https://reviews.llvm.org/D157150 may also be the culprit and
if so it should be handled first.

The script in `clang/utils/update_options_td_flags.py` can help. Take
the downstream side of all conflicts and then run the following:

```
% cd clang/include/clang/Driver
% ../../../utils/update_options_td_flags.py Options.td > Options.td.new
% mv Options.td.new Options.td
```

This will hopefully be sufficient, please take a look at the diff.

Differential Revision: https://reviews.llvm.org/D157151

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[llvm] Add missing StringExtras.h includes

In preparation for removing the `#include "llvm/ADT/StringExtras.h"`
from the header to source file of `llvm/Support/Error.h`, first add in
all the missing

[llvm] Add missing StringExtras.h includes

In preparation for removing the `#include "llvm/ADT/StringExtras.h"`
from the header to source file of `llvm/Support/Error.h`, first add in
all the missing includes that were previously included transitively
through this header.

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Reland "D144999 [MC][MachO]Only emits compact-unwind format for "canonical" personality symbols. For the rest, use DWARFs."

Reasons for rolling forward:
- the crash reported from Chromium was fi

Reland "D144999 [MC][MachO]Only emits compact-unwind format for "canonical" personality symbols. For the rest, use DWARFs."

Reasons for rolling forward:
- the crash reported from Chromium was fixed in D151824 (not related to this patch at all)
- since D152824 was committed, it should now be safe to roll this forward.

New change:
- add an additional _ in name check

This reverts commit 4980eead4d0b4666d53dad07afb091375b3a13a0.

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Revert "[RFC][MC][MachO]Only emits compact-unwind format for "canonical" personality symbols. For the rest, use DWARFs."

This reverts commit 09aaf53a05e3786eea374f3ce57574225036412d.
Causes toolchai

Revert "[RFC][MC][MachO]Only emits compact-unwind format for "canonical" personality symbols. For the rest, use DWARFs."

This reverts commit 09aaf53a05e3786eea374f3ce57574225036412d.
Causes toolchain asserts building libc++ for x86_64,
see https://reviews.llvm.org/D144999#4356215

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[RFC][MC][MachO]Only emits compact-unwind format for "canonical" personality symbols. For the rest, use DWARFs.

Details: https://github.com/rust-lang/rust/issues/102754

The MachO format uses 2 bits

[RFC][MC][MachO]Only emits compact-unwind format for "canonical" personality symbols. For the rest, use DWARFs.

Details: https://github.com/rust-lang/rust/issues/102754

The MachO format uses 2 bits to encode these personality funtions, with 0 reserved for "no-personality".
This means we can only have up to 3 personality. There are already three popular personalities: __gxx_personality_v0, __gcc_personality_v0, and __objc_personality_v0.
As a result, any system that needs custom-personality will run into a problem.

This patch implemented jyknight's proposal to simply force DWARFs for all non-canonical personality functions.

Differential Revision: https://reviews.llvm.org/D144999

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-fdebug-prefix-map=: make the last win when multiple prefixes match

For
`clang -c -g -fdebug-prefix-map=a/b=y -fdebug-prefix-map=a=x a/b/c.c`,
we apply the longest prefix substitution, but
GCC has a

-fdebug-prefix-map=: make the last win when multiple prefixes match

For
`clang -c -g -fdebug-prefix-map=a/b=y -fdebug-prefix-map=a=x a/b/c.c`,
we apply the longest prefix substitution, but
GCC has always been picking the last applicable option (`a=x`, see
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109591).

I feel that GCC's behavior is reasonable given the convention that the last
value wins for the same option.

Before D49466, Clang appeared to apply the shortest prefix substitution,
which likely made the least sense.

Reviewed By: #debug-info, scott.linder

Differential Revision: https://reviews.llvm.org/D148975

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[clang] Include the error message in file reading error diagnostic

in order to provide as much information as possible to the user. The
diagnostic will now look like for example:

error: error rea

[clang] Include the error message in file reading error diagnostic

in order to provide as much information as possible to the user. The
diagnostic will now look like for example:

error: error reading '/tmp/foo.c': Permission denied

(This addresses a FIXME from 2019, 9ef6c49baf45)

Differential revision: https://reviews.llvm.org/D146280

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[NFC][TargetParser] Replace uses of llvm/Support/Host.h

The forwarding header is left in place because of its use in
`polly/lib/External/isl/interface/extract_interface.cc`, but I have
added a GCC w

[NFC][TargetParser] Replace uses of llvm/Support/Host.h

The forwarding header is left in place because of its use in
`polly/lib/External/isl/interface/extract_interface.cc`, but I have
added a GCC warning about the fact it is deprecated, because it is used
in `isl` from where it is included by Polly.

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[NFC][TargetParser] Remove llvm/ADT/Triple.h

I also ran `git clang-format` to get the headers in the right order for
the new location, which has changed the order of other headers in two
files.

[clang] Use std::optional instead of llvm::Optional (NFC)

This patch replaces (llvm::|)Optional< with std::optional<. I'll post
a separate patch to remove #include "llvm/ADT/Optional.h".

This is p

[clang] Use std::optional instead of llvm::Optional (NFC)

This patch replaces (llvm::|)Optional< with std::optional<. I'll post
a separate patch to remove #include "llvm/ADT/Optional.h".

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716

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