Commit Graph

899 Commits

Author SHA1 Message Date
Ellis Hoag 12e78ff881 [InstrProf] Add the skipprofile attribute
As discussed in [0], this diff adds the `skipprofile` attribute to
prevent the function from being profiled while allowing profiled
functions to be inlined into it. The `noprofile` attribute remains
unchanged.

The `noprofile` attribute is used for functions where it is
dangerous to add instrumentation to while the `skipprofile` attribute is
used to reduce code size or performance overhead.

[0] https://discourse.llvm.org/t/why-does-the-noprofile-attribute-restrict-inlining/64108

Reviewed By: phosek

Differential Revision: https://reviews.llvm.org/D130807
2022-08-04 08:45:27 -07:00
Joshua Cranmer 2138c90645 [IR] Move support for dxil::TypedPointerType to LLVM core IR.
This allows the construct to be shared between different backends. However, it
still remains illegal to use TypedPointerType in LLVM IR--the type is intended
to remain an auxiliary type, not a real LLVM type. So no support is provided for
LLVM-C, nor bitcode, nor LLVM assembly (besides the bare minimum needed to make
Type->dump() work properly).

Reviewed By: beanz, nikic, aeubanks

Differential Revision: https://reviews.llvm.org/D130592
2022-08-04 10:41:11 -04:00
Schrodinger ZHU Yifan 304027206c [ThinLTO] Support aliased GlobalIFunc
Fixes https://github.com/llvm/llvm-project/issues/56290: when an ifunc is
aliased in LTO, clang will attempt to create an alias summary; however, as ifunc
is not included in the module summary, doing so will lead to crash.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D129009
2022-07-20 15:30:38 -07:00
Mitch Phillips 90e5a8ac47 Remove 'no_sanitize_memtag'. Add 'sanitize_memtag'.
For MTE globals, we should have clang emit the attribute for all GV's
that it creates, and then use that in the upcoming AArch64 global
tagging IR pass. We need a positive attribute for this sanitizer (rather
than implicit sanitization of all globals) because it needs to interact
with other parts of LLVM, including:

  1. Suppressing certain global optimisations (like merging),
  2. Emitting extra directives by the ASM writer, and
  3. Putting extra information in the symbol table entries.

While this does technically make the LLVM IR / bitcode format
non-backwards-compatible, nobody should have used this attribute yet,
because it's a no-op.

Reviewed By: eugenis

Differential Revision: https://reviews.llvm.org/D128950
2022-07-13 08:54:41 -07:00
Nick Desaulniers 2240d72f15 [X86] initial -mfunction-return=thunk-extern support
Adds support for:
* `-mfunction-return=<value>` command line flag, and
* `__attribute__((function_return("<value>")))` function attribute

Where the supported <value>s are:
* keep (disable)
* thunk-extern (enable)

thunk-extern enables clang to change ret instructions into jmps to an
external symbol named __x86_return_thunk, implemented as a new
MachineFunctionPass named "x86-return-thunks", keyed off the new IR
attribute fn_ret_thunk_extern.

The symbol __x86_return_thunk is expected to be provided by the runtime
the compiled code is linked against and is not defined by the compiler.
Enabling this option alone doesn't provide mitigations without
corresponding definitions of __x86_return_thunk!

This new MachineFunctionPass is very similar to "x86-lvi-ret".

The <value>s "thunk" and "thunk-inline" are currently unsupported. It's
not clear yet that they are necessary: whether the thunk pattern they
would emit is beneficial or used anywhere.

Should the <value>s "thunk" and "thunk-inline" become necessary,
x86-return-thunks could probably be merged into x86-retpoline-thunks
which has pre-existing machinery for emitting thunks (which could be
used to implement the <value> "thunk").

Has been found to build+boot with corresponding Linux
kernel patches. This helps the Linux kernel mitigate RETBLEED.
* CVE-2022-23816
* CVE-2022-28693
* CVE-2022-29901

See also:
* "RETBLEED: Arbitrary Speculative Code Execution with Return
Instructions."
* AMD SECURITY NOTICE AMD-SN-1037: AMD CPU Branch Type Confusion
* TECHNICAL GUIDANCE FOR MITIGATING BRANCH TYPE CONFUSION REVISION 1.0
  2022-07-12
* Return Stack Buffer Underflow / Return Stack Buffer Underflow /
  CVE-2022-29901, CVE-2022-28693 / INTEL-SA-00702

SystemZ may eventually want to support "thunk-extern" and "thunk"; both
options are used by the Linux kernel's CONFIG_EXPOLINE.

This functionality has been available in GCC since the 8.1 release, and
was backported to the 7.3 release.

Many thanks for folks that provided discrete review off list due to the
embargoed nature of this hardware vulnerability. Many Bothans died to
bring us this information.

Link: https://www.youtube.com/watch?v=IF6HbCKQHK8
Link: https://github.com/llvm/llvm-project/issues/54404
Link: https://gcc.gnu.org/legacy-ml/gcc-patches/2018-01/msg01197.html
Link: https://www.intel.com/content/www/us/en/developer/articles/technical/software-security-guidance/advisory-guidance/return-stack-buffer-underflow.html
Link: https://arstechnica.com/information-technology/2022/07/intel-and-amd-cpus-vulnerable-to-a-new-speculative-execution-attack/?comments=1
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ce114c866860aa9eae3f50974efc68241186ba60
Link: https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00702.html
Link: https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00707.html

Reviewed By: aaron.ballman, craig.topper

Differential Revision: https://reviews.llvm.org/D129572
2022-07-12 09:17:54 -07:00
Shilei Tian 1023ddaf77 [LLVM] Add the support for fmax and fmin in atomicrmw instruction
This patch adds the support for `fmax` and `fmin` operations in `atomicrmw`
instruction. For now (at least in this patch), the instruction will be expanded
to CAS loop. There are already a couple of targets supporting the feature. I'll
create another patch(es) to enable them accordingly.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D127041
2022-07-06 10:57:53 -04:00
Nikita Popov 7283f48a05 [IR] Remove support for insertvalue constant expression
This removes the insertvalue constant expression, as part of
https://discourse.llvm.org/t/rfc-remove-most-constant-expressions/63179.
This is very similar to the extractvalue removal from D125795.
insertvalue is also not supported in bitcode, so no auto-ugprade
is necessary.

ConstantExpr::getInsertValue() can be replaced with
IRBuilder::CreateInsertValue() or ConstantFoldInsertValueInstruction(),
depending on whether a constant result is required (with the latter
being fallible).

The ConstantExpr::hasIndices() and ConstantExpr::getIndices()
methods also go away here, because there are no longer any constant
expressions with indices.

Differential Revision: https://reviews.llvm.org/D128719
2022-07-04 09:27:22 +02:00
Nikita Popov 16033ffdd9 [ConstExpr] Remove more leftovers of extractvalue expression (NFC)
Remove some leftover bits of extractvalue handling after the
removal in D125795.
2022-06-29 10:45:19 +02:00
Chuanqi Xu 735e6c40b5 [Coroutines] Convert coroutine.presplit to enum attr
This is required by @nikic in https://reviews.llvm.org/D127383 to
decrease the cost to check whether a function is a coroutine and this
fixes a FIXME too.

Reviewed By: rjmccall, ezhulenev

Differential Revision: https://reviews.llvm.org/D127471
2022-06-14 14:23:46 +08:00
Vitaly Buka 665617182c [Bitcode] Don't use UINT_MAX for missing SanitizerMetadata
Looks like comment on D126100 was unnoticed.
2022-06-10 18:20:55 -07:00
Mitch Phillips 8db981d463 Add sanitizer-specific GlobalValue attributes.
Plan is the migrate the global variable metadata for sanitizers, that's
currently carried around generally in the 'llvm.asan.globals' section,
onto the global variable itself.

This patch adds the attribute and plumbs it through the LLVM IR and
bitcode formats, but is a no-op other than that so far.

Reviewed By: vitalybuka, kstoimenov

Differential Revision: https://reviews.llvm.org/D126100
2022-06-10 12:28:18 -07:00
Mitch Phillips 5d9de5f446 [NFC] Clang-format parts of D126929 and D126100 2022-06-07 14:08:43 -07:00
Augie Fackler 42861faa8e attributes: introduce allockind attr for describing allocator fn behavior
I chose to encode the allockind information in a string constant because
otherwise we would get a bit of an explosion of keywords to deal with
the possible permutations of allocation function types.

I'm not sure that CodeGen.h is the correct place for this enum, but it
seemed to kind of match the UWTableKind enum so I put it in the same
place. Constructive suggestions on a better location most certainly
encouraged.

Differential Revision: https://reviews.llvm.org/D123088
2022-05-31 10:01:17 -04:00
Fangrui Song bb353df589 [Bitcode] Simplify code after FUNC_CODE_BLOCKADDR_USERS changes (D124878)
Switch to the more common `Constant && !GlobalValue` test.
Use the more common `Worklist/Visited` variable names.
2022-05-11 20:27:12 -07:00
Wende Tan 6baaad740a [Bitcode] Include indirect users of BlockAddresses in bitcode
The original fix (commit 23ec5782c3) of
https://github.com/llvm/llvm-project/issues/52787 only adds `Function`s
that have `Instruction`s that directly use `BlockAddress`es into the
bitcode (`FUNC_CODE_BLOCKADDR_USERS`).

However, in either @rickyz's original reproducing code:

```
void f(long);

__attribute__((noinline)) static void fun(long x) {
  f(x + 1);
}

void repro(void) {
  fun(({
    label:
      (long)&&label;
  }));
}
```

```
...
define dso_local void @repro() #0 {
entry:
  br label %label

label:                                            ; preds = %entry
  tail call fastcc void @fun()
  ret void
}

define internal fastcc void @fun() unnamed_addr #1 {
entry:
  tail call void @f(i64 add (i64 ptrtoint (i8* blockaddress(@repro, %label) to i64), i64 1)) #3
  ret void
}
...
```

or the xfs and overlayfs in the Linux kernel, `BlockAddress`es (e.g.,
`i8* blockaddress(@repro, %label)`) may first compose `ConstantExpr`s
(e.g., `i64 ptrtoint (i8* blockaddress(@repro, %label) to i64)`) and
then used by `Instruction`s. This case is not handled by the original
fix.

This patch adds *indirect* users of `BlockAddress`es, i.e., the
`Instruction`s using some `Constant`s which further use the
`BlockAddress`es, into the bitcode as well, by doing depth-first
searches.

Fixes: https://github.com/llvm/llvm-project/issues/52787
Fixes: 23ec5782c3 ("[Bitcode] materialize Functions early when BlockAddress taken")

Reviewed By: nickdesaulniers

Differential Revision: https://reviews.llvm.org/D124878
2022-05-10 16:03:42 -07:00
Augie Fackler a907d36cfe Attributes: add a new `allocptr` attribute
This continues the push away from hard-coded knowledge about functions
towards attributes. We'll use this to annotate free(), realloc() and
cousins and obviate the hard-coded list of free functions.

Differential Revision: https://reviews.llvm.org/D123083
2022-04-26 13:57:11 -04:00
Chris Bieneman e6f44a3cd2 Add PointerType analysis for DirectX backend
As implemented this patch assumes that Typed pointer support remains in
the llvm::PointerType class, however this could be modified to use a
different subclass of llvm::Type that could be disallowed from use in
other contexts.

This does not rely on inserting typed pointers into the Module, it just
uses the llvm::PointerType class to track and unique types.

Fixes #54918

Reviewed By: kuhar

Differential Revision: https://reviews.llvm.org/D122268
2022-04-25 17:49:43 -05:00
Ilia Diachkov 6c69427e88 [SPIR-V](3/6) Add MC layer, object file support, and InstPrinter
The patch adds SPIRV-specific MC layer implementation, SPIRV object
file support and SPIRVInstPrinter.

Differential Revision: https://reviews.llvm.org/D116462

Authors: Aleksandr Bezzubikov, Lewis Crawford, Ilia Diachkov,
Michal Paszkowski, Andrey Tretyakov, Konrad Trifunovic

Co-authored-by: Aleksandr Bezzubikov <zuban32s@gmail.com>
Co-authored-by: Ilia Diachkov <iliya.diyachkov@intel.com>
Co-authored-by: Michal Paszkowski <michal.paszkowski@outlook.com>
Co-authored-by: Andrey Tretyakov <andrey1.tretyakov@intel.com>
Co-authored-by: Konrad Trifunovic <konrad.trifunovic@intel.com>
2022-04-20 01:10:25 +02:00
Chih-Ping Chen eab6e94f91 [DebugInfo] Add a TargetFuncName field in DISubprogram for
specifying DW_AT_trampoline as a string. Also update the signature
of DIBuilder::createFunction to reflect this addition.

Differential Revision: https://reviews.llvm.org/D123697
2022-04-15 16:38:23 -04:00
Nick Desaulniers 23ec5782c3 [Bitcode] materialize Functions early when BlockAddress taken
IRLinker builds a work list of functions to materialize, then moves them
from a source module to a destination module one at a time.

This is a problem for blockaddress Constants, since they need not refer
to the function they are used in; IPSCCP is quite good at sinking these
constants deep into other functions when passed as arguments.

This would lead to curious errors during LTO:
  ld.lld: error: Never resolved function from blockaddress ...
based on the ordering of function definitions in IR.

The problem was that IRLinker would basically do:

  for function f in worklist:
    materialize f
    splice f from source module to destination module

in one pass, with Functions being lazily added to the running worklist.
This confuses BitcodeReader, which cannot disambiguate whether a
blockaddress is referring to a function which has not yet been parsed
("materialized") or is simply empty because its body was spliced out.
This causes BitcodeReader to insert Functions into its BasicBlockFwdRefs
list incorrectly, as it will never re-materialize an already
materialized (but spliced out) function.

Because of the possibility that blockaddress Constants may appear in
Functions other than the ones they reference, this patch adds a new
bitcode function code FUNC_CODE_BLOCKADDR_USERS that is a simple list of
Functions that contain BlockAddress Constants that refer back to this
Function, rather then the Function they are scoped in. We then
materialize those functions when materializing `f` from the example loop
above. This might over-materialize Functions should the user of
BitcodeReader ultimately decide not to link those Functions, but we can
at least now we can avoid this ordering related issue with blockaddresses.

Fixes: https://github.com/llvm/llvm-project/issues/52787
Fixes: https://github.com/ClangBuiltLinux/linux/issues/1215

Reviewed By: dexonsmith

Differential Revision: https://reviews.llvm.org/D120781
2022-04-12 11:38:35 -07:00
Argyrios Kyrtzidis 330268ba34 [Support/Hash functions] Change the `final()` and `result()` of the hashing functions to return an array of bytes
Returning `std::array<uint8_t, N>` is better ergonomics for the hashing functions usage, instead of a `StringRef`:

* When returning `StringRef`, client code is "jumping through hoops" to do string manipulations instead of dealing with fixed array of bytes directly, which is more natural
* Returning `std::array<uint8_t, N>` avoids the need for the hasher classes to keep a field just for the purpose of wrapping it and returning it as a `StringRef`

As part of this patch also:

* Introduce `TruncatedBLAKE3` which is useful for using BLAKE3 as the hasher type for `HashBuilder` with non-default hash sizes.
* Make `MD5Result` inherit from `std::array<uint8_t, 16>` which improves & simplifies its API.

Differential Revision: https://reviews.llvm.org/D123100
2022-04-05 21:38:06 -07:00
Chris Bieneman 9130e471fe Add DXContainer
DXIL is wrapped in a container format defined by the DirectX 11
specification. Codebases differ in calling this format either DXBC or
DXILContainer.

Since eventually we want to add support for DXBC as a target
architecture and the format is used by DXBC and DXIL, I've termed it
DXContainer here.

Most of the changes in this patch are just adding cases to switch
statements to address warnings.

Reviewed By: pete

Differential Revision: https://reviews.llvm.org/D122062
2022-03-29 14:34:23 -05:00
Nikita Popov 40d7d2ed66 [Bitcode] Check for live uses of llvm.cmdline/embedded.module
The one use check here is very misleading: At this point we should
actually have no uses, because the only possible use in llvm.used
was already dropped. But because the use in llvm.used is generally
bitcasted, we end up still having one dead use here.

What we actually want to check is that there are no live uses, for
which a helper has recently been added.
2022-03-23 15:39:39 +01:00
Nikita Popov a0d2b0aa65 [Bitcode] Clarify that extractvalue/insertvalue constexprs are not supported
Bitcode currently cannot encode these. Throw a more obvious error
in this case, rather than failing an operand count assertion.
2022-03-11 16:50:24 +01:00
Nikita Popov b190108693 [Bitcode] Encode alloca address space
Since D101045, allocas are no longer required to be part of the
default alloca address space. There may be allocas in multiple
different address spaces. However, the bitcode reader would
simply assume the default alloca address space, resulting in
either an error or incorrect IR.

Add an optional record for allocas which encodes the address
space.
2022-03-11 16:08:38 +01:00
Augie Fackler d664c4b73c Attributes: add a new allocalign attribute
This will let us start moving away from hard-coded attributes in
MemoryBuiltins.cpp and put the knowledge about various attribute
functions in the compilers that emit those calls where it probably
belongs.

Differential Revision: https://reviews.llvm.org/D117921
2022-03-04 15:57:53 -05:00
Tong Zhang 17ce89fa80 [SanitizerBounds] Add support for NoSanitizeBounds function
Currently adding attribute no_sanitize("bounds") isn't disabling
-fsanitize=local-bounds (also enabled in -fsanitize=bounds). The Clang
frontend handles fsanitize=array-bounds which can already be disabled by
no_sanitize("bounds"). However, instrumentation added by the
BoundsChecking pass in the middle-end cannot be disabled by the
attribute.

The fix is very similar to D102772 that added the ability to selectively
disable sanitizer pass on certain functions.

In this patch, if no_sanitize("bounds") is provided, an additional
function attribute (NoSanitizeBounds) is attached to IR to let the
BoundsChecking pass know we want to disable local-bounds checking. In
order to support this feature, the IR is extended (similar to D102772)
to make Clang able to preserve the information and let BoundsChecking
pass know bounds checking is disabled for certain function.

Reviewed By: melver

Differential Revision: https://reviews.llvm.org/D119816
2022-03-01 18:47:02 +01:00
Fangrui Song 7aaf024dac [BitcodeWriter] Fix cases of some functions
`WriteIndexToFile` is used by external projects so I do not touch it.
2022-01-31 16:46:11 -08:00
Fangrui Song 85dfe19b36 [ModuleUtils] Move EmbedBufferInModule to LLVMTransformsUtils
D116542 adds EmbedBufferInModule which introduces a layer violation
(https://llvm.org/docs/CodingStandards.html#library-layering).
See 2d5f857a1e for detail.

EmbedBufferInModule does not use BitcodeWriter functionality and should be moved
LLVMTransformsUtils. While here, change the function case to the prevailing
convention.

It seems that EmbedBufferInModule just follows the steps of
EmbedBitcodeInModule. EmbedBitcodeInModule calls WriteBitcodeToFile but has IR
update operations which ideally should be refactored to another library.

Reviewed By: jhuber6

Differential Revision: https://reviews.llvm.org/D118666
2022-01-31 16:33:57 -08:00
Joseph Huber 4a780aa13e [LLVM] Resolve layer violation in BitcodeWriter
Summary:
The changes introduced in D116542 added a dependency on TransformUtils
to use the `appendToCompilerUsed` method. This created a circular
dependency. This patch simply copies the needed function locally to
remove the dependency.
2022-01-31 19:01:08 -05:00
Joseph Huber 551b177452 [OpenMP] Add a flag for embedding a file into the module
This patch adds support for a flag `-fembed-offload-binary` to embed a
file as an ELF section in the output by placing it in a global variable.
This can be used to bundle offloading files with the host binary so it
can be accessed by the linker. The section is named using the
`-fembed-offload-section` option.

Depends on D116541

Reviewed By: JonChesterfield

Differential Revision: https://reviews.llvm.org/D116542
2022-01-31 15:56:00 -05:00
Chih-Ping Chen 28bfa57a73 [DebugInfo] Add stringLocationExp field to DIStringType
DIStringType is used to encode the debug info of a character object
in Fortran. A Fortran deferred-length character object is typically
implemented as a pair of the following two pieces of info: An address
of the raw storage of the characters, and the length of the object.
The stringLocationExp field contains the DIExpression to get to the
raw storage.

This patch also enables the emission of DW_AT_data_location attribute
in a DW_TAG_string_type debug info entry based on stringLocationExp
in DIStringType.

A test is also added to ensure that the bitcode reader is backward
compatible with the old DIStringType format.

Differential Revision: https://reviews.llvm.org/D117586
2022-01-26 11:56:57 -05:00
Nikita Popov aa97bc116d [NFC] Remove uses of PointerType::getElementType()
Instead use either Type::getPointerElementType() or
Type::getNonOpaquePointerElementType().

This is part of D117885, in preparation for deprecating the API.
2022-01-25 09:44:52 +01:00
Roman Lebedev 62b1682570
[Opaqueptrs][IR Serialization] Improve inlineasm [de]serialization
The bitcode reader expected that the pointers are typed,
so that it can extract the function type for the assembly
so `bitc::CST_CODE_INLINEASM` did not explicitly store said function type.

I'm not really sure how the upgrade path will look for existing bitcode,
but i think we can easily support opaque pointers going forward,
by simply storing the function type.

Reviewed By: #opaque-pointers, nikic

Differential Revision: https://reviews.llvm.org/D116341
2021-12-30 13:54:37 +03:00
Sami Tolvanen 5dc8aaac39 [llvm][IR] Add no_cfi constant
With Control-Flow Integrity (CFI), the LowerTypeTests pass replaces
function references with CFI jump table references, which is a problem
for low-level code that needs the address of the actual function body.

For example, in the Linux kernel, the code that sets up interrupt
handlers needs to take the address of the interrupt handler function
instead of the CFI jump table, as the jump table may not even be mapped
into memory when an interrupt is triggered.

This change adds the no_cfi constant type, which wraps function
references in a value that LowerTypeTestsModule::replaceCfiUses does not
replace.

Link: https://github.com/ClangBuiltLinux/linux/issues/1353

Reviewed By: nickdesaulniers, pcc

Differential Revision: https://reviews.llvm.org/D108478
2021-12-20 12:55:32 -08:00
Mingming Liu 09a704c5ef [LTO] Ignore unreachable virtual functions in WPD in hybrid LTO.
Differential Revision: https://reviews.llvm.org/D115492
2021-12-14 20:18:04 +00:00
Kazu Hirata ca2f53897a [CodeGen] Use range-based for loops (NFC) 2021-12-04 08:48:05 -08:00
Kazu Hirata f6bce30cf9 [llvm] Use range-based for loops (NFC) 2021-11-20 18:42:10 -08:00
Kazu Hirata 7ca14f6044 [llvm] Use range-based for loops (NFC) 2021-11-18 09:09:52 -08:00
Arthur Eubanks 05963a3d66 Revert "[DebugInfo] Enforce implicit constraints on `distinct` MDNodes"
This reverts commit ee76525698.

Causes crashes, see comments in D104827.
2021-11-09 14:27:55 -08:00
Scott Linder ee76525698 [DebugInfo] Enforce implicit constraints on `distinct` MDNodes
Add UNIQUED and DISTINCT properties in Metadata.def and use them to
implement restrictions on the `distinct` property of MDNodes:

* DIExpression can currently be parsed from IR or read from bitcode
  as `distinct`, but this property is silently dropped when printing
  to IR. This causes accepted IR to fail to round-trip. As DIExpression
  appears inline at each use in the canonical form of IR, it cannot
  actually be `distinct` anyway, as there is no syntax to describe it.
* Similarly, DIArgList is conceptually always uniqued. It is currently
  restricted to only appearing in contexts where there is no syntax for
  `distinct`, but for consistency it is treated equivalently to
  DIExpression in this patch.
* DICompileUnit is already restricted to always being `distinct`, but
  along with adding general support for the inverse restriction I went
  ahead and described this in Metadata.def and updated the parser to be
  general. Future nodes which have this restriction can share this
  support.

The new UNIQUED property applies to DIExpression and DIArgList, and
forbids them to be `distinct`. It also implies they are canonically
printed inline at each use, rather than via MDNode ID.

The new DISTINCT property applies to DICompileUnit, and requires it to
be `distinct`.

A potential alternative change is to forbid the non-inline syntax for
DIExpression entirely, as is done with DIArgList implicitly by requiring
it appear in the context of a function. For example, we would forbid:

    !named = !{!0}
    !0 = !DIExpression()

Instead we would only accept the equivalent inlined version:

    !named = !{!DIExpression()}

This essentially removes the ability to create a `distinct` DIExpression
by construction, as there is no syntax for `distinct` inline. If this
patch is accepted as-is, the result would be that the non-canonical
version is accepted, but the following would be an error and produce a diagnostic:

    !named = !{!0}
    ; error: 'distinct' not allowed for !DIExpression()
    !0 = distinct !DIExpression()

Also update some documentation to consistently use the inline syntax for
DIExpression, and to describe the restrictions on `distinct` for nodes
where applicable.

Reviewed By: StephenTozer, t-tye

Differential Revision: https://reviews.llvm.org/D104827
2021-11-09 18:19:11 +00:00
Reid Kleckner 89b57061f7 Move TargetRegistry.(h|cpp) from Support to MC
This moves the registry higher in the LLVM library dependency stack.
Every client of the target registry needs to link against MC anyway to
actually use the target, so we might as well move this out of Support.

This allows us to ensure that Support doesn't have includes from MC/*.

Differential Revision: https://reviews.llvm.org/D111454
2021-10-08 14:51:48 -07:00
Itay Bookstein 40ec1c0f16 [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.
2021-10-06 19:33:10 -07:00
Arthur Eubanks 05392466f0 Reland [IR] Increase max alignment to 4GB
Currently the max alignment representable is 1GB, see D108661.
Setting the align of an object to 4GB is desirable in some cases to make sure the lower 32 bits are clear which can be used for some optimizations, e.g. https://crbug.com/1016945.

This uses an extra bit in instructions that carry an alignment. We can store 15 bits of "free" information, and with this change some instructions (e.g. AtomicCmpXchgInst) use 14 bits.
We can increase the max alignment representable above 4GB (up to 2^62) since we're only using 33 of the 64 values, but I've just limited it to 4GB for now.

The one place we have to update the bitcode format is for the alloca instruction. It stores its alignment into 5 bits of a 32 bit bitfield. I've added another field which is 8 bits and should be future proof for a while. For backward compatibility, we check if the old field has a value and use that, otherwise use the new field.

Updating clang's max allowed alignment will come in a future patch.

Reviewed By: hans

Differential Revision: https://reviews.llvm.org/D110451
2021-10-06 13:29:23 -07:00
Arthur Eubanks 569346f274 Revert "Reland [IR] Increase max alignment to 4GB"
This reverts commit 8d64314ffe.
2021-10-06 11:38:11 -07:00
Arthur Eubanks 8d64314ffe Reland [IR] Increase max alignment to 4GB
Currently the max alignment representable is 1GB, see D108661.
Setting the align of an object to 4GB is desirable in some cases to make sure the lower 32 bits are clear which can be used for some optimizations, e.g. https://crbug.com/1016945.

This uses an extra bit in instructions that carry an alignment. We can store 15 bits of "free" information, and with this change some instructions (e.g. AtomicCmpXchgInst) use 14 bits.
We can increase the max alignment representable above 4GB (up to 2^62) since we're only using 33 of the 64 values, but I've just limited it to 4GB for now.

The one place we have to update the bitcode format is for the alloca instruction. It stores its alignment into 5 bits of a 32 bit bitfield. I've added another field which is 8 bits and should be future proof for a while. For backward compatibility, we check if the old field has a value and use that, otherwise use the new field.

Updating clang's max allowed alignment will come in a future patch.

Reviewed By: hans

Differential Revision: https://reviews.llvm.org/D110451
2021-10-06 11:03:51 -07:00
Arthur Eubanks 72cf8b6044 Revert "[IR] Increase max alignment to 4GB"
This reverts commit df84c1fe78.

Breaks some bots
2021-10-06 10:21:35 -07:00
Arthur Eubanks df84c1fe78 [IR] Increase max alignment to 4GB
Currently the max alignment representable is 1GB, see D108661.
Setting the align of an object to 4GB is desirable in some cases to make sure the lower 32 bits are clear which can be used for some optimizations, e.g. https://crbug.com/1016945.

This uses an extra bit in instructions that carry an alignment. We can store 15 bits of "free" information, and with this change some instructions (e.g. AtomicCmpXchgInst) use 14 bits.
We can increase the max alignment representable above 4GB (up to 2^62) since we're only using 33 of the 64 values, but I've just limited it to 4GB for now.

The one place we have to update the bitcode format is for the alloca instruction. It stores its alignment into 5 bits of a 32 bit bitfield. I've added another field which is 8 bits and should be future proof for a while. For backward compatibility, we check if the old field has a value and use that, otherwise use the new field.

Updating clang's max allowed alignment will come in a future patch.

Reviewed By: hans

Differential Revision: https://reviews.llvm.org/D110451
2021-10-06 09:54:14 -07:00
Kazu Hirata 3081de8c72 [llvm] Migrate from getNumArgOperands to arg_size (NFC)
Note that getNumArgOperands is considered a legacy name.  See
llvm/include/llvm/IR/InstrTypes.h for details.
2021-10-05 08:29:19 -07:00
Arthur Eubanks a7b4ce9cfd [NFC][AttributeList] Replace index_begin/end with an iterator
We expose the fact that we rely on unsigned wrapping to iterate through
all indexes. This can be confusing. Rather, keeping it as an
implementation detail through an iterator is less confusing and is less
code.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D110885
2021-10-01 10:17:41 -07:00