[Object] Add ELF section type for offloading objects

Currently we use the `.llvm.offloading` section to store device-side
objects inside the host, creating a fat binary. The contents of these
sectio

[Object] Add ELF section type for offloading objects

Currently we use the `.llvm.offloading` section to store device-side
objects inside the host, creating a fat binary. The contents of these
sections is currently determined by the name of the section while it
should ideally be determined by its type. This patch adds the new
`SHT_LLVM_OFFLOADING` section type to the ELF section types. Which
should make it easier to identify this specific data format.

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D129052

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[Propeller] Encode address offsets of basic blocks relative to the end of the previous basic blocks.

This is a resurrection of D106421 with the change that it keeps backward-compatibility. This mean

[Propeller] Encode address offsets of basic blocks relative to the end of the previous basic blocks.

This is a resurrection of D106421 with the change that it keeps backward-compatibility. This means decoding the previous version of `LLVM_BB_ADDR_MAP` will work. This is required as the profile mapping tool is not released with LLVM (AutoFDO). As suggested by @jhenderson we rename the original section type value to `SHT_LLVM_BB_ADDR_MAP_V0` and assign a new value to the `SHT_LLVM_BB_ADDR_MAP` section type. The new encoding adds a version byte to each function entry to specify the encoding version for that function. This patch also adds a feature byte to be used with more flexibility in the future. An use-case example for the feature field is encoding multi-section functions more concisely using a different format.

Conceptually, the new encoding emits basic block offsets and sizes as label differences between each two consecutive basic block begin and end label. When decoding, offsets must be aggregated along with basic block sizes to calculate the final offsets of basic blocks relative to the function address.

This encoding uses smaller values compared to the existing one (offsets relative to function symbol).
Smaller values tend to occupy fewer bytes in ULEB128 encoding. As a result, we get about 17% total reduction in the size of the bb-address-map section (from about 11MB to 9MB for the clang PGO binary).
The extra two bytes (version and feature fields) incur a small 3% size overhead to the `LLVM_BB_ADDR_MAP` section size.

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D121346

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[MC] Fix letter case of some MCSection member functions

[MC][ELF] Use SHF_SUNW_NODISCARD instead of SHF_GNU_RETAIN on Solaris

As requested in D107955 <https://reviews.llvm.org/D107955>, this patch
splits off the `MC` and `CodeGen` parts and adds a testca

[MC][ELF] Use SHF_SUNW_NODISCARD instead of SHF_GNU_RETAIN on Solaris

As requested in D107955 <https://reviews.llvm.org/D107955>, this patch
splits off the `MC` and `CodeGen` parts and adds a testcase.

Tested on `sparcv9-sun-solaris2.11`, `amd64-pc-solaris2.11`, and
`x86_64-pc-linux-gnu`.

Differential Revision: https://reviews.llvm.org/D120318

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[MC][ELF] Support for zero flag section groups

This change introduces support for zero flag ELF section groups to LLVM.
LLVM already supports COMDAT sections, which in ELF are a special type
of ELF

[MC][ELF] Support for zero flag section groups

This change introduces support for zero flag ELF section groups to LLVM.
LLVM already supports COMDAT sections, which in ELF are a special type
of ELF section groups. These are generally useful to enable linker GC
where you want a group of sections to always travel together, that is to
be either retained or discarded as a whole, but without the COMDAT
semantics. Other ELF assemblers already support zero flag ELF section
groups and this change helps us reach feature parity.

Differential Revision: https://reviews.llvm.org/D95851

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[MC] Support SHF_GNU_RETAIN as section flag 'R'

On Linux target triples, GNU as sets EI_OSABI to ELFOSABI_GNU when SHF_GNU_RETAIN is used。
On `*-*-freebsd`, it usually sets EI_OSABI to ELFOSABI_FREE

[MC] Support SHF_GNU_RETAIN as section flag 'R'

On Linux target triples, GNU as sets EI_OSABI to ELFOSABI_GNU when SHF_GNU_RETAIN is used。
On `*-*-freebsd`, it usually sets EI_OSABI to ELFOSABI_FREEBSD.

GNU ld respects SHF_GNU_RETAIN only for ELFOSABI_FREEBSD/ELFOSABI_GNU.
https://sourceware.org/bugzilla/show_bug.cgi?id=27282

MC doesn't set ELFOSABI_GNU for SHF_GNU_RETAIN/STB_GNU_UNIQUE/STT_GNU_IFUNC.
MC assembled object files do not have special semantics in GNU ld.

Reviewed By: psmith

Differential Revision: https://reviews.llvm.org/D95730

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Introduce and use a new section type for the bb_addr_map section.

This patch lets the bb_addr_map (renamed to __llvm_bb_addr_map) section use a special section type (SHT_LLVM_BB_ADDR_MAP) instead of

Introduce and use a new section type for the bb_addr_map section.

This patch lets the bb_addr_map (renamed to __llvm_bb_addr_map) section use a special section type (SHT_LLVM_BB_ADDR_MAP) instead of SHT_PROGBITS. This would help parsers, dumpers and other tools to use the sh_type ELF field to identify this section rather than relying on string comparison on the section name.

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D88199

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[MC] Set sh_link to 0 if the associated symbol is undefined

Part of https://bugs.llvm.org/show_bug.cgi?id=41734

LTO can drop externally available definitions. Such AssociatedSymbol is
not associate

[MC] Set sh_link to 0 if the associated symbol is undefined

Part of https://bugs.llvm.org/show_bug.cgi?id=41734

LTO can drop externally available definitions. Such AssociatedSymbol is
not associated with a symbol. ELFWriter::writeSection() will assert.

Allow a SHF_LINK_ORDER section to have sh_link=0.

We need to give sh_link a syntax, a literal zero in the linked-to symbol
position, e.g. `.section name,"ao",@progbits,0`

Reviewed By: pcc

Differential Revision: https://reviews.llvm.org/D72899

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Revert rGf0bab7875e78e01c149d12302dcc4b6d4c43e25c - "Triple.h - reduce Twine.h include to forward declarations. NFC."

This causes ICEs on the clang-ppc64be buildbots and I've limited ability to tria

Revert rGf0bab7875e78e01c149d12302dcc4b6d4c43e25c - "Triple.h - reduce Twine.h include to forward declarations. NFC."

This causes ICEs on the clang-ppc64be buildbots and I've limited ability to triage the problem.

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Triple.h - reduce Twine.h include to forward declarations. NFC.

Move include down to a number of other files that had an implicit dependency on the Twine class.

[MC][COFF][ELF] Reject instructions in IMAGE_SCN_CNT_UNINITIALIZED_DATA/SHT_NOBITS sections

For `.bss; nop`, MC inappropriately calls abort() (via report_fatal_error()) with a message
`cannot have f

[MC][COFF][ELF] Reject instructions in IMAGE_SCN_CNT_UNINITIALIZED_DATA/SHT_NOBITS sections

For `.bss; nop`, MC inappropriately calls abort() (via report_fatal_error()) with a message
`cannot have fixups in virtual section!`
It is a bug to crash for invalid user input. Fix it by erroring out early in EmitInstToData().

Similarly, emitIntValue() in a virtual section (SHT_NOBITS in ELF) can crash with the mssage
`non-zero initializer found in section '.bss'` (see D4199)
It'd be nice to report the location but so many directives can call emitIntValue()
and it is difficult to track every location.
Note, COFF does not crash because MCAssembler::writeSectionData() is not
called for an IMAGE_SCN_CNT_UNINITIALIZED_DATA section.

Note, GNU as' arm64 backend reports ``Error: attempt to store non-zero value in section `.bss'``
for a non-zero .inst but fails to do so for other instructions.
We simply reject all instructions, even if the encoding is all zeros.

The Mach-O counterpart is D48517 (see `test/MC/MachO/zerofill-text.s`)

Reviewed By: rnk, skan

Differential Revision: https://reviews.llvm.org/D78138

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[MC] Replace MCSection*::getName() with MCSection::getName(). NFC

I plan to use MCSection::getName() in D78138. Having the function in the base class is also convenient for debugging.

Reviewed By:

[MC] Replace MCSection*::getName() with MCSection::getName(). NFC

I plan to use MCSection::getName() in D78138. Having the function in the base class is also convenient for debugging.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D78251

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[MC] Rename MCSection*::getSectionName() to getName(). NFC

A pending change will merge MCSection*::getName() to MCSection::getName().

[MC][ELF] Rename MC related "Associated" to "LinkedToSym"

"linked-to section" is used by the ELF spec. By analogy, "linked-to
symbol" is a good name for the signature symbol. The word "linked-to"
i

[MC][ELF] Rename MC related "Associated" to "LinkedToSym"

"linked-to section" is used by the ELF spec. By analogy, "linked-to
symbol" is a good name for the signature symbol. The word "linked-to"
implies a directed edge and makes it clear its relation with "sh_link",
while one can argue that "associated" means an undirected edge.

Also, combine tests and add precise SMLoc to improve diagnostics.

Reviewed By: eugenis, grimar, jhenderson

Differential Revision: https://reviews.llvm.org/D74082

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Add IR support, ELF section and user documentation for partitioning feature.

The partitioning feature was proposed here:
http://lists.llvm.org/pipermail/llvm-dev/2019-February/130583.html

This is m

Add IR support, ELF section and user documentation for partitioning feature.

The partitioning feature was proposed here:
http://lists.llvm.org/pipermail/llvm-dev/2019-February/130583.html

This is mostly just documentation. The feature itself will be contributed
in subsequent patches.

Differential Revision: https://reviews.llvm.org/D60242

llvm-svn: 361923

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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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[MC] Clean up unused inline function and non-anchor defaulted destructors; NFCI

Summary:
Take care of some missing clean-ups that belong with r249548 and some
other copy/paste that had happened. In

[MC] Clean up unused inline function and non-anchor defaulted destructors; NFCI

Summary:
Take care of some missing clean-ups that belong with r249548 and some
other copy/paste that had happened. In particular, the destructors are
no longer vtable anchors after r249548; and `setSectionName` in
`MCSectionWasm` is private and unused since r313058 culled its only
caller. The destructors are now implicitly defined, and the unused
function is removed.

Reviewers: nemanjai, jasonliu, grosbach

Reviewed By: nemanjai

Subscribers: sbc100, aheejin, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D57182

llvm-svn: 353597

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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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[Hexagon] Handle Hexagon's SHF_HEX_GPREL section flag

llvm-svn: 346494

[MC] Add assembler support for .cg_profile.

Object FIle Representation
At codegen time this is emitted into the ELF file a pair of symbol indices and a weight. In assembly it looks like:

.cg_profi

[MC] Add assembler support for .cg_profile.

Object FIle Representation
At codegen time this is emitted into the ELF file a pair of symbol indices and a weight. In assembly it looks like:

.cg_profile a, b, 32
.cg_profile freq, a, 11
.cg_profile freq, b, 20

When writing an ELF file these are put into a SHT_LLVM_CALL_GRAPH_PROFILE (0x6fff4c02) section as (uint32_t, uint32_t, uint64_t) tuples as (from symbol index, to symbol index, weight).

Differential Revision: https://reviews.llvm.org/D44965

llvm-svn: 333823

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CodeGen: support an extension to pass linker options on ELF

Introduce an extension to support passing linker options to the linker.
These would be ignored by older linkers, but newer linkers which s

CodeGen: support an extension to pass linker options on ELF

Introduce an extension to support passing linker options to the linker.
These would be ignored by older linkers, but newer linkers which support
this feature would be able to process the linker.

Emit a special discarded section `.linker-option`. The content of this
section is a pair of strings (key, value). The key is a type identifier for
the parameter. This allows for an argument free parameter that will be
processed by the linker with the value being the parameter. As an example,
`lib` identifies a library to be linked against, traditionally the `-l`
argument for Unix-based linkers with the parameter being the library name.

Thanks to James Henderson, Cary Coutant, Rafael Espinolda, Sean Silva
for the valuable discussion on the design of this feature.

llvm-svn: 323783

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[Triple] Add isThumb and isARM functions.

Summary:
isThumb returns true for Thumb triples (little and big endian), isARM
returns true for ARM triples (little and big endian).
There are a few more ch

[Triple] Add isThumb and isARM functions.

Summary:
isThumb returns true for Thumb triples (little and big endian), isARM
returns true for ARM triples (little and big endian).
There are a few more checks using arm/thumb that are not covered by
those functions, e.g. that the architecture is either ARM or Thumb
(little endian) or ARM/Thumb little endian only.

Reviewers: javed.absar, rengolin, kristof.beyls, t.p.northover

Reviewed By: rengolin

Subscribers: llvm-commits, aemerson

Differential Revision: https://reviews.llvm.org/D34682

llvm-svn: 310781

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MC, Object: Reserve a section type, SHT_LLVM_ODRTAB, for the ODR table.

This is part of the ODR checker proposal:
http://lists.llvm.org/pipermail/llvm-dev/2017-June/113820.html

Per discussion on th

MC, Object: Reserve a section type, SHT_LLVM_ODRTAB, for the ODR table.

This is part of the ODR checker proposal:
http://lists.llvm.org/pipermail/llvm-dev/2017-June/113820.html

Per discussion on the gnu-gabi mailing list [1] the section type range
0x6fff4c00..0x6fff4cff is reserved for LLVM.

[1] https://sourceware.org/ml/gnu-gabi/2017-q2/msg00030.html

Differential Revision: https://reviews.llvm.org/D33978

llvm-svn: 305407

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Move Object format code to lib/BinaryFormat.

This creates a new library called BinaryFormat that has all of
the headers from llvm/Support containing structure and layout
definitions for various type

Move Object format code to lib/BinaryFormat.

This creates a new library called BinaryFormat that has all of
the headers from llvm/Support containing structure and layout
definitions for various types of binary formats like dwarf, coff,
elf, etc as well as the code for identifying a file from its
magic.

Differential Revision: https://reviews.llvm.org/D33843

llvm-svn: 304864

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Sort the remaining #include lines in include/... and lib/....

I did this a long time ago with a janky python script, but now
clang-format has built-in support for this. I fed clang-format every
line

Sort the remaining #include lines in include/... and lib/....

I did this a long time ago with a janky python script, but now
clang-format has built-in support for this. I fed clang-format every
line with a #include and let it re-sort things according to the precise
LLVM rules for include ordering baked into clang-format these days.

I've reverted a number of files where the results of sorting includes
isn't healthy. Either places where we have legacy code relying on
particular include ordering (where possible, I'll fix these separately)
or where we have particular formatting around #include lines that
I didn't want to disturb in this patch.

This patch is *entirely* mechanical. If you get merge conflicts or
anything, just ignore the changes in this patch and run clang-format
over your #include lines in the files.

Sorry for any noise here, but it is important to keep these things
stable. I was seeing an increasing number of patches with irrelevant
re-ordering of #include lines because clang-format was used. This patch
at least isolates that churn, makes it easy to skip when resolving
conflicts, and gets us to a clean baseline (again).

llvm-svn: 304787

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