We plan to use the "docs" directory as the home for our "www" pages,
similar to how it is for the libcxx project.

A section briefly mentioning the planned future enhancements has also
been included.

Reviewed By: lntue

Differential Revision: https://reviews.llvm.org/D123761

This fixes CVE-2019-15847, preventing random number generation from
being merged.

Reviewed By: lkail

Differential Revision: https://reviews.llvm.org/D122783

This patch modifies mergeLocalIds to not delete duplicate local ids in
`this` relation. This allows the ordering of the final local ids for `this`
to be determined more easily, which is generally required when other objects
refer to these local ids.

Reviewed By: arjunp

Differential Revision: https://reviews.llvm.org/D123866

In the past, `clang --target=riscv64-unknown-linux-gnu -mno-relax -c hello.s` will assemble hello.s without relaxation, but `clang --target=riscv64-unknown-linux-gnu -mno-relax -fno-integrated-as -c hello.s` doesn't pass the `-mno-relax` option to assembler, and assemble with relaxation
This patch pass the -mno-relax option to assembler when -fno-integrated-as is specified.

Differential Revision: https://reviews.llvm.org/D120639

This revision folds transpose splat to a new splat with the transposed vector type. For a splat, there is no need to actually do transpose for it, it would be more effective to just build a new splat as the result.

Reviewed By: ThomasRaoux

Differential Revision: https://reviews.llvm.org/D123765

functions are not treated as [[nodiscard]].

The compiler might choose to treat them as [[nodiscard]] without the
involvement of libc++ if we allow it to recognize them as builtins.

This reverts commit 9d9eddd3.

This was review feedback that I missed in the phab review:
https://reviews.llvm.org/D123760

This class is a helper for 'parser-like' use cases of LogicalResult
where the implicit conversion to bool is tolerable.  It is used by the
operation asmparsers, but is more generic functionality that is closely
aligned with LogicalResult.  Hoist it up to LogicalResult.h to make it
more accessible.  This is part of Issue #54884

Differential Revision: https://reviews.llvm.org/D123760

This is extended to all `std::` functions that take a reference to a
value and return a reference (or pointer) to that same value: `move`,
`forward`, `move_if_noexcept`, `as_const`, `addressof`, and the
libstdc++-specific function `__addressof`.

We still require these functions to be declared before they can be used,
but don't instantiate their definitions unless their addresses are
taken. Instead, code generation, constant evaluation, and static
analysis are given direct knowledge of their effect.

This change aims to reduce various costs associated with these functions
-- per-instantiation memory costs, compile time and memory costs due to
creating out-of-line copies and inlining them, code size at -O0, and so
on -- so that they are not substantially more expensive than a cast.
Most of these improvements are very small, but I measured a 3% decrease
in -O0 object file size for a simple C++ source file using the standard
library after this change.

We now automatically infer the `const` and `nothrow` attributes on these
now-builtin functions, in particular meaning that we get a warning for
an unused call to one of these functions.

In C++20 onwards, we disallow taking the addresses of these functions,
per the C++20 "addressable function" rule. In earlier language modes, a
compatibility warning is produced but the address can still be taken.

The same infrastructure is extended to the existing MSVC builtin
`__GetExceptionInfo`, which is now only recognized in namespace `std`
like it always should have been.

This is a re-commit of
  fc309010,
  a571f82a, and
  64c045e2
which were reverted in
  e75d8b70
due to a crasher bug where CodeGen would emit a builtin glvalue as an
rvalue if it constant-folds.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D123345

This patch makes printing of FailedToMaterialize errors in llvm-jitlink
conditional on the -show-err-failed-to-materialize option, which defaults to
false.

FailedToMaterialize errors are not root-cause errors: they're generated when a
symbol is requested but cannot be provided because of a failure that was
reported on some other error path. They typically don't convey actionable
information, and tend to flood error logs making root cause errors harder to
spot. Hiding FailedToMaterialize errors by default addresses these issues.

This reverts commit daabcf5f.

This patch still had on-going discussion that should be closed before
committing.

When we run the CGSCC pass we should only invest time on the SCC. We can
initialize AAs with information from the module slice but we should not
update those AAs. We make an exception for are call site of the SCC as
they are helpful providing information for the SCC.

Minor modifications to pointer privatization allow us to perform it even
in the CGSCC pass, similar to ArgumentPromotion.

Opaque pointers are enabled by default since D123300, so test IR should be
regenerated correspondingly.

Differential Revision: https://reviews.llvm.org/D123842

On some platforms _ZTIi may not be present (see discussion at
https://reviews.llvm.org/rG43acef48d38e). We don't need this symbol for the
test to work, so just add -phony-externals to the testcase to suppress the
error.

ptxas fails to parse such syntax:

    mov.u64 %rd1, ($str);
    fatal   : Parsing error near '$str': syntax error

A new MCAsmInfo option was added because InParens parameter of
MCExpr::print is not sufficient to disable parens
completely. MCExpr::print resets it to false for a recursive call in
case of unary or binary expressions.

Targets that require parens around identifiers that start with '$'
should always pass MCAsmInfo to MCExpr::print.
Therefore 'operator<<(raw_ostream &, MCExpr&)' should be avoided
because it calls MCExpr::print with nullptr MAI.

Differential Revision: https://reviews.llvm.org/D123702

The generic form of the op is too verbose and in some cases not
readable. On pass failure, ops have been so far printed in generic form
to provide a (stronger) guarantee that the IR print succeeds. However,
in a large number of pass failure cases, the IR is still valid and
the custom printers for the ops will succeed. In fact, readability is
highly desirable post pass failure. This revision provides an option to
print ops in their custom/pretty-printed form on IR failure -- this
option is unsafe and there is no guarantee it will succeed. It's
disabled by default and can be turned on only if needed.

Differential Revision: https://reviews.llvm.org/D123893

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D123666

A randomized structure needs to use a designated or default initializer.
Using a non-designated initializer will result in values being assigned
to the wrong fields.

Differential Revision: https://reviews.llvm.org/D123763

Fix indentation within the lit test - agpr-copy-no-free-registers.ll.

Reviewed By: rampitec

Differential Revision: https://reviews.llvm.org/D123809

It's idiomatic to require that plugins (especially platform plugins) be
installed to handle special edge kinds. If the plugins are not installed and an
object is loaded that uses one of the special edge kinds then we want to error
out rather than asserting.

This adjusts the path iteration - `paths` is a null-terminated sequence
of C strings, creating an array from a single contiguous buffer.  We
would previously continue to iterate indefinitely as we did not check if
we had encountered the terminator.

Found by inspection.

This makes it a little easier to reuse the libc++ tests for another
std::lib (specifically libstdc++).

The regex_error::what() strings are different in other
implementations, so should be tested with LIBCPP_ASSERT so that those
checks are skipped for other implementations.

The value of ECMAScript constant is non-zero in other implementations,
and conditionally for libc++, so adjust the preprocessor condition for
that too.

Reviewed By: ldionne, #libc, philnik, Mordante

Spies: Mordante, philnik, libcxx-commits

Differential Revision: https://reviews.llvm.org/D122574

Adds flang/include/flang/Common/log2-visit.h, which defines
a Fortran::common::visit() template function that is a drop-in
replacement for std::visit().  Modifies most use sites in
the front-end and runtime to use common::visit().

The C++ standard mandates that std::visit() have O(1) execution
time, which forces implementations to build dispatch tables.
This new common::visit() is O(log2 N) in the number of alternatives
in a variant<>, but that N tends to be small and so this change
produces a fairly significant improvement in compiler build
memory requirements, a 5-10% improvement in compiler build time,
and a small improvement in compiler execution time.

Building with -DFLANG_USE_STD_VISIT causes common::visit()
to be an alias for std::visit().

Calls to common::visit() with multiple variant arguments
are referred to std::visit(), pending further work.

This change is enabled only for GCC builds with GCC >= 9;
an earlier attempt (D122441) ran into bugs in some versions of
clang and was reverted rather than simply disabled; and it is
not well tested with MSVC. In non-GCC and older GCC builds,
common::visit() is simply an alias for std::visit().

Calling hasOneUse can be expensive on nodes with multiple results.
Especially when some results are Chains. By checking the opcode first,
we can avoid walking the uses if it isn't an interesting node,
and thus avoid calling hasOneUse on a node that might have many uses.

Found by profiling the IR given in D123857.

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D123881

BaseLayer was originally written as an IRCompileLayer, but there was no need for
this restriction. Using IRLayer gives clients more flexibility in choosing the
underlying layer.

Issue: https://github.com/llvm/llvm-project/issues/54430

For incoming values of phi nodes added to an outlined function to accommodate different exit paths in the function, when a value is a constant that is passed into the outlined function as an argument, we find the corresponding value in the first extracted function used to fill the overall outlined function. When this value is an argument, the corresponding value used will be the old value, prior to outlining. This patch maintains a mapping from these values to arguments, and uses this mapping to update the added phi node accordingly.

Reviewers: paquette

Recommit of d6eb480a

Differential Revision: https://reviews.llvm.org/D122206

This patch takes advantage of the Commutative trait on operation
to remove identical commutative operations where the operands are swapped.

The second operation below can be removed since `arith.addi` is commutative.
```
%1 = arith.addi %a, %b : i32
%2 = arith.addi %b, %a : i32
```

Reviewed By: rriddle

Differential Revision: https://reviews.llvm.org/D123492

This reverts commit aed923b1.

It causes some buildbot test failures.

This reverts commit 2a404cdf.

It didn't address the built bot failures.

https://lab.llvm.org/buildbot/#/builders/171/builds/13231
https://lab.llvm.org/buildbot/#/builders/186/builds/5520

Adds a flag to `ClangTidyContext` that is used to indicate to checks that fixes will only be applied one at a time.
This is to indicate to checks that each fix emitted should not depend on any other fixes emitted across the translation unit.
I've currently implemented the `IncludeInserter`, `LoopConvertCheck` and `PreferMemberInitializerCheck` to use these support these modes.

Reasoning behind this is in use cases like `clangd` it's only possible to apply one fix at a time.
For include inserter checks, the include is only added once for the first diagnostic that requires it, this will result in subsequent fixes not having the included needed.

A similar issue is seen in the `PreferMemberInitializerCheck` where the `:` will only be added for the first member that needs fixing.

Fixes emitted in `StandaloneDiagsMode` will likely result in malformed code if they are applied all together, conversely fixes currently emitted may result in malformed c...

Revert "Extend support for std::move etc to also cover std::as_const and"
Revert "Update test to handle opaque pointers flag flip."

It crashes on libcxx tests https://lab.llvm.org/buildbot/#/builders/85/builds/8174

This reverts commit fc309010.
This reverts commit a571f82a.
This reverts commit 64c045e2.