Cleanup LLVMObject headers

Most notably,

llvm/Object/Binary.h no longer includes llvm/Support/MemoryBuffer.h
llvm/Object/MachOUniversal*.h no longer include llvm/Object/Archive.h
llvm/Object/TapiUn

Cleanup LLVMObject headers

Most notably,

llvm/Object/Binary.h no longer includes llvm/Support/MemoryBuffer.h
llvm/Object/MachOUniversal*.h no longer include llvm/Object/Archive.h
llvm/Object/TapiUniversal.h no longer includes llvm/Object/TapiFile.h

llvm-project preprocessed size:
before: 1068185081
after: 1068324320

Discourse thread: https://discourse.llvm.org/t/include-what-you-use-include-cleanup
Differential Revision: https://reviews.llvm.org/D119457

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[LTO] An option to disable automatic bitcode upgrade

Bitcode upgrade automatically takes in place when the current compiler version doesn't match the one building the input modules. The upgrade is v

[LTO] An option to disable automatic bitcode upgrade

Bitcode upgrade automatically takes in place when the current compiler version doesn't match the one building the input modules. The upgrade is very expansive for large applications and unnecessary when users are sure the two compilers do not have a version issue, even if their versions mismatch literally. An optional to disable the automatic bitcode upgrade will be handy in such case.

Reviewed By: wenlei

Differential Revision: https://reviews.llvm.org/D109869

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[IRSymTab] Mark __stack_chk_guard used

`__stack_chk_guard` is a global variable that has no uses before the LLVM code generation phase (how it is defined is platform-dependent). LTO needs to preserv

[IRSymTab] Mark __stack_chk_guard used

`__stack_chk_guard` is a global variable that has no uses before the LLVM code generation phase (how it is defined is platform-dependent). LTO needs to preserve this symbol for that reason. Currently, legacy LTO API preserves it by hardcoding the logic in Internalizer, but this symbol is not preserved by regular LTO API in thinlink phase. This patch marks `__stack_chk_guard` used during IR symbol table writing since this is how builtin functions are preserved by thinlink by using `RuntimeLibcalls.def`.

Reviewed By: MaskRay, tejohnson

Differential Revision: https://reviews.llvm.org/D112595

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[IR][NFC] Rename getBaseObject to getAliaseeObject

To better reflect the meaning of the now-disambiguated {GlobalValue,
GlobalAlias}::getBaseObject after breaking off GlobalIFunc::getResolverFunctio

[IR][NFC] Rename getBaseObject to getAliaseeObject

To better reflect the meaning of the now-disambiguated {GlobalValue,
GlobalAlias}::getBaseObject after breaking off GlobalIFunc::getResolverFunction
(D109792), the function is renamed to getAliaseeObject.

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Resolve {GlobalValue,GloalIndirectSymol}::getBaseObject confusion

While both GlobalAlias and GlobalIFunc are GlobalIndirectSymbol, their
`getIndirectSymbol()` usage is quite different (GlobalIFunc's

Resolve {GlobalValue,GloalIndirectSymol}::getBaseObject confusion

While both GlobalAlias and GlobalIFunc are GlobalIndirectSymbol, their
`getIndirectSymbol()` usage is quite different (GlobalIFunc's resolver
is an entity different from GlobalIFunc itself).

As discussed on https://lists.llvm.org/pipermail/llvm-dev/2020-September/144904.html
("[IR] Modelling of GlobalIFunc"), the name `getBaseObject` is confusing when
used with GlobalIFunc.

To resolve the confusion:

* Move GloalIndirectSymol::getBaseObject to GlobalAlias:: (GlobalIFunc should use `getResolver` instead)
* Change GlobalValue::getBaseObject not to inspect GlobalIFunc. Note: the function has 7 references.
* Add GlobalIFunc::getResolverFunction to peel off potential ConstantExpr indirection
(`strlen` in `test/LTO/Resolution/X86/ifunc.ll`)

Note: GlobalIFunc::getResolver (like GlobalAlias::getAliasee which does not peel
off ConstantExpr indirection) is kept to be used by ValueEnumerator.

Reviewed By: ibookstein

Differential Revision: https://reviews.llvm.org/D109792

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[LTO] Add SelectionKind to IRSymtab and use it in ld.lld/LLVMgold

In PGO, a C++ external linkage function `foo` has a private counter
`__profc_foo` and a private `__profd_foo` in a `comdat nodedupli

[LTO] Add SelectionKind to IRSymtab and use it in ld.lld/LLVMgold

In PGO, a C++ external linkage function `foo` has a private counter
`__profc_foo` and a private `__profd_foo` in a `comdat nodeduplicate`.

A `__attribute__((weak))` function `foo` has a weak hidden counter `__profc_foo`
and a private `__profd_foo` in a `comdat nodeduplicate`.

In `ld.lld a.o b.o`, say a.o defines an external linkage `foo` and b.o
defines a weak `foo`. Currently we treat `comdat nodeduplicate` as `comdat any`,
ld.lld will incorrectly consider `b.o:__profc_foo` non-prevailing. In the worst
case when `b.o:__profd_foo` is retained and `b.o:__profc_foo` isn't, there will
be dangling reference causing an `undefined hidden symbol` error.

Add SelectionKind to `Comdat` in IRSymtab and let linkers ignore nodeduplicate comdat.

Differential Revision: https://reviews.llvm.org/D106228

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[NFC][OpaquePtr] Use GlobalValue::getValueType() more

Instead of getType()->getElementType().

PR51018: Remove explicit conversions from SmallString to StringRef to future-proof against C++23

C++23 will make these conversions ambiguous - so fix them to make the
codebase forward-compatible wit

PR51018: Remove explicit conversions from SmallString to StringRef to future-proof against C++23

C++23 will make these conversions ambiguous - so fix them to make the
codebase forward-compatible with C++23 (& a follow-up change I've made
will make this ambiguous/invalid even in <C++23 so we don't regress
this & it generally improves the code anyway)

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[IRSymTab] Set FB_used on llvm.compiler.used symbols

IR symbol table does not parse inline asm. A symbol only referenced by inline
asm is not in the IR symbol table, so LTO does not know that the de

[IRSymTab] Set FB_used on llvm.compiler.used symbols

IR symbol table does not parse inline asm. A symbol only referenced by inline
asm is not in the IR symbol table, so LTO does not know that the definition (in
another translation unit) is referenced and may internalize it, even if that
definition has `__attribute__((used))` (which lowers to `llvm.compiler.used` on
ELF targets since D97446).

```
// cabac.c
__attribute__((used)) const uint8_t ff_h264_cabac_tables[...] = {...};

// h264_cabac.c
asm("lea ff_h264_cabac_tables(%rip), %0" : ...);
```

`__attribute__((used))` is the recommended way to tell the compiler there may
be inline asm references, so the usage is perfectly fine. This patch
conservatively sets the `FB_used` bit on `llvm.compiler.used` symbols to work
around the IR symbol table limitation. Note: before D97446, Clang never emitted
symbols in the `llvm.compiler.used` list, so this change does not punish any
Clang emitted global object.

Without the patch, `ff_h264_cabac_tables` may be assigned to a non-external
partition and get internalized. Then we will get a linker error because the
`cabac.c` definition is not exposed.

Differential Revision: https://reviews.llvm.org/D97755

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collectUsedGlobalVariables: migrate SmallPtrSetImpl overload to SmallVecImpl overload after D97128

And delete the SmallPtrSetImpl overload.

While here, decrease inline element counts from 8 to 4. S

collectUsedGlobalVariables: migrate SmallPtrSetImpl overload to SmallVecImpl overload after D97128

And delete the SmallPtrSetImpl overload.

While here, decrease inline element counts from 8 to 4. See D97128 for the choice.

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D97257

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[llvm] Use llvm::is_contained (NFC)

Remove GlobalValue::getAlignment().

This function is deceptive at best: it doesn't return what you'd expect.
If you have an arbitrary GlobalValue and you want to determine the
alignment of that poin

Remove GlobalValue::getAlignment().

This function is deceptive at best: it doesn't return what you'd expect.
If you have an arbitrary GlobalValue and you want to determine the
alignment of that pointer, Value::getPointerAlignment() returns the
correct value. If you want the actual declared alignment of a function
or variable, GlobalObject::getAlignment() returns that.

This patch switches all the users of GlobalValue::getAlignment to an
appropriate alternative.

Differential Revision: https://reviews.llvm.org/D80368

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Revert "Remove redundant "std::move"s in return statements"

The build failed with

error: call to deleted constructor of 'llvm::Error'

errors.

This reverts commit 1c2241a7936bf85aa68aef94bd40c3b

Revert "Remove redundant "std::move"s in return statements"

The build failed with

error: call to deleted constructor of 'llvm::Error'

errors.

This reverts commit 1c2241a7936bf85aa68aef94bd40c3ba77d8ddf2.

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Remove redundant "std::move"s in return statements

Make llvm::StringRef to std::string conversions explicit.

This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.

This is mostly m

Make llvm::StringRef to std::string conversions explicit.

This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.

This is mostly mechanical from a custom clang-tidy check, with a lot of
manual fixups. It uncovers a lot of minor inefficiencies.

This doesn't actually modify StringRef yet, I'll do that in a follow-up.

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[ELF] Implement Dependent Libraries Feature

This patch implements a limited form of autolinking primarily designed to allow
either the --dependent-library compiler option, or "comment lib" pragmas (

[ELF] Implement Dependent Libraries Feature

This patch implements a limited form of autolinking primarily designed to allow
either the --dependent-library compiler option, or "comment lib" pragmas (
https://docs.microsoft.com/en-us/cpp/preprocessor/comment-c-cpp?view=vs-2017) in
C/C++ e.g. #pragma comment(lib, "foo"), to cause an ELF linker to automatically
add the specified library to the link when processing the input file generated
by the compiler.

Currently this extension is unique to LLVM and LLD. However, care has been taken
to design this feature so that it could be supported by other ELF linkers.

The design goals were to provide:

- A simple linking model for developers to reason about.
- The ability to to override autolinking from the linker command line.
- Source code compatibility, where possible, with "comment lib" pragmas in other
environments (MSVC in particular).

Dependent library support is implemented differently for ELF platforms than on
the other platforms. Primarily this difference is that on ELF we pass the
dependent library specifiers directly to the linker without manipulating them.
This is in contrast to other platforms where they are mapped to a specific
linker option by the compiler. This difference is a result of the greater
variety of ELF linkers and the fact that ELF linkers tend to handle libraries in
a more complicated fashion than on other platforms. This forces us to defer
handling the specifiers to the linker.

In order to achieve a level of source code compatibility with other platforms
we have restricted this feature to work with libraries that meet the following
"reasonable" requirements:

1. There are no competing defined symbols in a given set of libraries, or
if they exist, the program owner doesn't care which is linked to their
program.
2. There may be circular dependencies between libraries.

The binary representation is a mergeable string section (SHF_MERGE,
SHF_STRINGS), called .deplibs, with custom type SHT_LLVM_DEPENDENT_LIBRARIES
(0x6fff4c04). The compiler forms this section by concatenating the arguments of
the "comment lib" pragmas and --dependent-library options in the order they are
encountered. Partial (-r, -Ur) links are handled by concatenating .deplibs
sections with the normal mergeable string section rules. As an example, #pragma
comment(lib, "foo") would result in:

.section ".deplibs","MS",@llvm_dependent_libraries,1
.asciz "foo"

For LTO, equivalent information to the contents of a the .deplibs section can be
retrieved by the LLD for bitcode input files.

LLD processes the dependent library specifiers in the following way:

1. Dependent libraries which are found from the specifiers in .deplibs sections
of relocatable object files are added when the linker decides to include that
file (which could itself be in a library) in the link. Dependent libraries
behave as if they were appended to the command line after all other options. As
a consequence the set of dependent libraries are searched last to resolve
symbols.
2. It is an error if a file cannot be found for a given specifier.
3. Any command line options in effect at the end of the command line parsing apply
to the dependent libraries, e.g. --whole-archive.
4. The linker tries to add a library or relocatable object file from each of the
strings in a .deplibs section by; first, handling the string as if it was
specified on the command line; second, by looking for the string in each of the
library search paths in turn; third, by looking for a lib<string>.a or
lib<string>.so (depending on the current mode of the linker) in each of the
library search paths.
5. A new command line option --no-dependent-libraries tells LLD to ignore the
dependent libraries.

Rationale for the above points:

1. Adding the dependent libraries last makes the process simple to understand
from a developers perspective. All linkers are able to implement this scheme.
2. Error-ing for libraries that are not found seems like better behavior than
failing the link during symbol resolution.
3. It seems useful for the user to be able to apply command line options which
will affect all of the dependent libraries. There is a potential problem of
surprise for developers, who might not realize that these options would apply
to these "invisible" input files; however, despite the potential for surprise,
this is easy for developers to reason about and gives developers the control
that they may require.
4. This algorithm takes into account all of the different ways that ELF linkers
find input files. The different search methods are tried by the linker in most
obvious to least obvious order.
5. I considered adding finer grained control over which dependent libraries were
ignored (e.g. MSVC has /nodefaultlib:<library>); however, I concluded that this
is not necessary: if finer control is required developers can fall back to using
the command line directly.

RFC thread: http://lists.llvm.org/pipermail/llvm-dev/2019-March/131004.html.

Differential Revision: https://reviews.llvm.org/D60274

llvm-svn: 360984

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Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the ne

Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636

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Put "built-in" function definitions in global Used list, for LTO. (fix bug 34169)

When building with LTO, builtin functions that are defined but whose calls have not been inserted yet, get internali

Put "built-in" function definitions in global Used list, for LTO. (fix bug 34169)

When building with LTO, builtin functions that are defined but whose calls have not been inserted yet, get internalized. The Global Dead Code Elimination phase in the new LTO implementation then removes these function definitions. Later optimizations add calls to those functions, and the linker then dies complaining that there are no definitions. This CL fixes the new LTO implementation to check if a function is builtin, and if so, to not internalize (and later DCE) the function. As part of this fix I needed to move the RuntimeLibcalls.{def,h} files from the CodeGen subidrectory to the IR subdirectory. I have updated all the files that accessed those two files to access their new location.

Fixes PR34169

Patch by Caroline Tice!

Differential Revision: https://reviews.llvm.org/D49434

llvm-svn: 337847

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IWYU for llvm-config.h in llvm, additions.

See r331124 for how I made a list of files missing the include.
I then ran this Python script:

for f in open('filelist.txt'):
f = f.strip()

IWYU for llvm-config.h in llvm, additions.

See r331124 for how I made a list of files missing the include.
I then ran this Python script:

for f in open('filelist.txt'):
f = f.strip()
fl = open(f).readlines()

found = False
for i in xrange(len(fl)):
p = '#include "llvm/'
if not fl[i].startswith(p):
continue
if fl[i][len(p):] > 'Config':
fl.insert(i, '#include "llvm/Config/llvm-config.h"\n')
found = True
break
if not found:
print 'not found', f
else:
open(f, 'w').write(''.join(fl))

and then looked through everything with `svn diff | diffstat -l | xargs -n 1000 gvim -p`
and tried to fix include ordering and whatnot.

No intended behavior change.

llvm-svn: 331184

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Sink Analysis/ObjectUtil(canBeOmittedFromSymbolTable) into IR so it can be legitimately be used by Object/IRSymtab

llvm-svn: 328135

Object: Improve COFF irsymtab comdat representation.

Change the representation of COFF comdats so that a COFF linker
is able to accurately resolve comdats between IR and native object
files. Specifi

Object: Improve COFF irsymtab comdat representation.

Change the representation of COFF comdats so that a COFF linker
is able to accurately resolve comdats between IR and native object
files. Specifically, apply name mangling to comdat names consistently
with native object files, and do not export comdats with an internal
leader because they do not affect symbol resolution.

Differential Revision: https://reviews.llvm.org/D40278

llvm-svn: 318805

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Object: Downgrade invalid weak externals from an assert fail to an llvm::Error when creating an irsymtab.

This fixes bitcode emission for modules containing invalid weak externals.

llvm-svn: 312686

[LTO] Prevent dead stripping and internalization of symbols with sections

Summary:
ELF linkers generate __start_<secname> and __stop_<secname> symbols
when there is a value in a section <secname> wh

[LTO] Prevent dead stripping and internalization of symbols with sections

Summary:
ELF linkers generate __start_<secname> and __stop_<secname> symbols
when there is a value in a section <secname> where the name is a valid
C identifier. If dead stripping determines that the values declared
in section <secname> are dead, and we then internalize (and delete)
such a symbol, programs that reference the corresponding start and end
section symbols will get undefined reference linking errors.

To fix this, add the section name to the IRSymtab entry when a symbol is
defined in a specific section. Then use this in the gold-plugin to mark
the symbol as external and visible from outside the summary when the
section name is a valid C identifier.

Reviewers: pcc

Subscribers: mehdi_amini, inglorion, eraman, llvm-commits

Differential Revision: https://reviews.llvm.org/D35639

llvm-svn: 309009

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Object: Teach irsymtab::read() to try to use the irsymtab that we wrote to disk.

Fixes PR27551.

Differential Revision: https://reviews.llvm.org/D33974

llvm-svn: 306488

Object: Add version and producer fields to the irsymtab header. NFCI.

These will be necessary in order to handle upgrades from old bitcode
files.

Differential Revision: https://reviews.llvm.org/D33

Object: Add version and producer fields to the irsymtab header. NFCI.

These will be necessary in order to handle upgrades from old bitcode
files.

Differential Revision: https://reviews.llvm.org/D33972

llvm-svn: 306486

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