Fix miscompile with [[no_unique_address]] struct fields.

If a zero-sized field has a non-trivial initializer, it should prevent
the overall struct initialization from being folded to a constant duri

Fix miscompile with [[no_unique_address]] struct fields.

If a zero-sized field has a non-trivial initializer, it should prevent
the overall struct initialization from being folded to a constant during
IR generation. Don't just ignore zero-sized fields entirely in IR
constant emission.

show more ...

Fix size of flexible array initializers, and re-enable assertions.

In D123649, I got the formula for getFlexibleArrayInitChars slightly
wrong: the flexible array elements can be contained in the tai

Fix size of flexible array initializers, and re-enable assertions.

In D123649, I got the formula for getFlexibleArrayInitChars slightly
wrong: the flexible array elements can be contained in the tail padding
of the struct. Fix the formula to account for that.

With the fixed formula, we run into another issue: in some cases, we
were emitting extra padding for flexible arrray initializers. Fix
CGExprConstant so it uses a packed struct when necessary, to avoid this
extra padding.

Differential Revision: https://reviews.llvm.org/D123826

show more ...

Restrict lvalue-to-rvalue conversions in CGExprConstant.

We were generating wrong code for cxx20-consteval-crash.cpp: instead of
loading a value of a variable, we were using its address as the
initi

Restrict lvalue-to-rvalue conversions in CGExprConstant.

We were generating wrong code for cxx20-consteval-crash.cpp: instead of
loading a value of a variable, we were using its address as the
initializer.

Found while adding code to verify the size of constant initializers.

Differential Revision: https://reviews.llvm.org/D123648

show more ...

[Clang] Implement __builtin_source_location.

This builtin returns the address of a global instance of the
`std::source_location::__impl` type, which must be defined (with an
appropriate shape) befor

[Clang] Implement __builtin_source_location.

This builtin returns the address of a global instance of the
`std::source_location::__impl` type, which must be defined (with an
appropriate shape) before calling the builtin.

It will be used to implement std::source_location in libc++ in a
future change. The builtin is compatible with GCC's implementation,
and libstdc++'s usage. An intentional divergence is that GCC declares
the builtin's return type to be `const void*` (for
ease-of-implementation reasons), while Clang uses the actual type,
`const std::source_location::__impl*`.

In order to support this new functionality, I've also added a new
'UnnamedGlobalConstantDecl'. This artificial Decl is modeled after
MSGuidDecl, and is used to represent a generic concept of an lvalue
constant with global scope, deduplicated by its value. It's possible
that MSGuidDecl itself, or some of the other similar sorts of things
in Clang might be able to be refactored onto this more-generic
concept, but there's enough special-case weirdness in MSGuidDecl that
I gave up attempting to share code there, at least for now.

Finally, for compatibility with libstdc++'s <source_location> header,
I've added a second exception to the "cannot cast from void* to T* in
constant evaluation" rule. This seems a bit distasteful, but feels
like the best available option.

Reviewers: aaron.ballman, erichkeane

Differential Revision: https://reviews.llvm.org/D120159

show more ...

Remove reference type when checking const structs

ConstStructBuilder::Finalize in CGExprConstant.ccp assumes that the
passed in QualType is a RecordType. In some instances, the type is a
reference

Remove reference type when checking const structs

ConstStructBuilder::Finalize in CGExprConstant.ccp assumes that the
passed in QualType is a RecordType. In some instances, the type is a
reference to a RecordType and the reference needs to be removed first.

Differential Revision: https://reviews.llvm.org/D117376

show more ...

[Clang] Add __builtin_function_start

Control-Flow Integrity (CFI) replaces references to address-taken
functions with pointers to the CFI jump table. This is a problem
for low-level code, such as op

[Clang] Add __builtin_function_start

Control-Flow Integrity (CFI) replaces references to address-taken
functions with pointers to the CFI jump table. This is a problem
for low-level code, such as operating system kernels, which may
need the address of an actual function body without the jump table
indirection.

This change adds the __builtin_function_start() builtin, which
accepts an argument that can be constant-evaluated to a function,
and returns the address of the function body.

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

Depends on D108478

Reviewed By: pcc, rjmccall

Differential Revision: https://reviews.llvm.org/D108479

show more ...

[CodeGen] Avoid deprecated ConstantAddress constructor

Change all uses of the deprecated constructor to pass the
element type explicitly and drop it.

For cases where the correct element type was no

[CodeGen] Avoid deprecated ConstantAddress constructor

Change all uses of the deprecated constructor to pass the
element type explicitly and drop it.

For cases where the correct element type was not immediately
obvious to me or would require a slightly larger change I'm
falling back to explicitly calling getPointerElementType() for now.

show more ...

PR52183: Don't emit code for a void-typed constant expression.

This is unnecessary in general, and wrong when the expression invokes a
consteval function.

Fix a crash on valid consteval code.

Not all constants are emitted within the context of a function, so use
the module's ASTContext instead because 1) that's the same as the
current function ASTCont

Fix a crash on valid consteval code.

Not all constants are emitted within the context of a function, so use
the module's ASTContext instead because 1) that's the same as the
current function ASTContext, and 2) the module can never be null.

Fixes PR50787.

show more ...

[Matrix] Implement C-style explicit type conversions for matrix types.

This implements C-style type conversions for matrix types, as specified
in clang/docs/MatrixTypes.rst.

Fixes PR47141.

Reviewe

[Matrix] Implement C-style explicit type conversions for matrix types.

This implements C-style type conversions for matrix types, as specified
in clang/docs/MatrixTypes.rst.

Fixes PR47141.

Reviewed By: fhahn

Differential Revision: https://reviews.llvm.org/D99037

show more ...

[CGExpr] Use getCharWidth() more consistently in CCGExprConstant. NFC

Most of CGExprConstant.cpp is using the CharUnits abstraction
and is using getCharWidth() (directly of indirectly) when converti

[CGExpr] Use getCharWidth() more consistently in CCGExprConstant. NFC

Most of CGExprConstant.cpp is using the CharUnits abstraction
and is using getCharWidth() (directly of indirectly) when converting
between size of a char and size in bits. This patch is making that
abstraction more consistent by adding CharTy to the CodeGenTypeCache
(honoring getCharWidth() when mapping from char to LLVM IR types,
instead of using Int8Ty directly).

Reviewed By: rjmccall

Differential Revision: https://reviews.llvm.org/D94979

show more ...

Revert "Following up on PR48517, fix handling of template arguments that refer"

Combined with 'da98651 - Revert "DR2064:
decltype(E) is only a dependent', this change (5a391d3) caused verifier
error

Revert "Following up on PR48517, fix handling of template arguments that refer"

Combined with 'da98651 - Revert "DR2064:
decltype(E) is only a dependent', this change (5a391d3) caused verifier
errors when building Chromium. See https://crbug.com/1168494#c1 for a
reproducer.

Additionally it reverts changes that were dependent on this one, see
below.

> Following up on PR48517, fix handling of template arguments that refer
> to dependent declarations.
>
> Treat an id-expression that names a local variable in a templated
> function as being instantiation-dependent.
>
> This addresses a language defect whereby a reference to a dependent
> declaration can be formed without any construct being value-dependent.
> Fixing that through value-dependence turns out to be problematic, so
> instead this patch takes the approach (proposed on the core reflector)
> of allowing the use of pointers or references to (but not values of)
> dependent declarations inside value-dependent expressions, and instead
> treating template arguments as dependent if they evaluate to a constant
> involving such dependent declarations.
>
> This ends up affecting a bunch of OpenMP tests, due to OpenMP
> imprecisely handling instantiation-dependent constructs, bailing out
> early instead of processing dependent constructs to the extent possible
> when handling the template.
>
> Previously committed as 8c1f2d15b826591cdf6bd6b468b8a7d23377b29e, and
> reverted because a dependency commit was reverted.

This reverts commit 5a391d38ac6c561ba908334d427f26124ed9132e.

It also restores clang/test/SemaCXX/coroutines.cpp to its state before
da986511fb9da1a46a0ca4dba2e49e2426036303.

Revert "[c++20] P1907R1: Support for generalized non-type template arguments of scalar type."

> Previously committed as 9e08e51a20d0d2b1c5724bb17e969d036fced4cd, and
> reverted because a dependency commit was reverted. This incorporates the
> following follow-on commits that were also reverted:
>
> 7e84aa1b81e72d44bcc58ffe1731bfc7abb73ce0 by Simon Pilgrim
> ed13d8c66781b50ff007cb089c5905f9bb9e8af2 by me
> 95c7b6cadbc9a3d4376ef44edbeb3c8bb5b8d7fc by Sam McCall
> 430d5d8429473c2b10b109991d7577a3cea41140 by Dave Zarzycki

This reverts commit 4b574008aef5a7235c1f894ab065fe300d26e786.

Revert "[msabi] Mangle a template argument referring to array-to-pointer decay"

> [msabi] Mangle a template argument referring to array-to-pointer decay
> applied to an array the same as the array itself.
>
> This follows MS ABI, and corrects a regression from the implementation
> of generalized non-type template parameters, where we "forgot" how to
> mangle this case.

This reverts commit 18e093faf726d15f210ab4917142beec51848258.

show more ...

[c++20] P1907R1: Support for generalized non-type template arguments of scalar type.

Previously committed as 9e08e51a20d0d2b1c5724bb17e969d036fced4cd, and
reverted because a dependency commit was re

[c++20] P1907R1: Support for generalized non-type template arguments of scalar type.

Previously committed as 9e08e51a20d0d2b1c5724bb17e969d036fced4cd, and
reverted because a dependency commit was reverted. This incorporates the
following follow-on commits that were also reverted:

7e84aa1b81e72d44bcc58ffe1731bfc7abb73ce0 by Simon Pilgrim
ed13d8c66781b50ff007cb089c5905f9bb9e8af2 by me
95c7b6cadbc9a3d4376ef44edbeb3c8bb5b8d7fc by Sam McCall
430d5d8429473c2b10b109991d7577a3cea41140 by Dave Zarzycki

show more ...

Revert "[c++20] P1907R1: Support for generalized non-type template arguments of scalar type."

This reverts commit 9e08e51a20d0d2b1c5724bb17e969d036fced4cd.

This is part of 5 commits being reverted

Revert "[c++20] P1907R1: Support for generalized non-type template arguments of scalar type."

This reverts commit 9e08e51a20d0d2b1c5724bb17e969d036fced4cd.

This is part of 5 commits being reverted due to https://crbug.com/1161059. See bug for repro.

show more ...

[c++20] P1907R1: Support for generalized non-type template arguments of scalar type.

[c++20] For P0732R2 / P1907R1: Basic frontend support for class types as
non-type template parameters.

Create a unique TemplateParamObjectDecl instance for each such value,
representing the globally

[c++20] For P0732R2 / P1907R1: Basic frontend support for class types as
non-type template parameters.

Create a unique TemplateParamObjectDecl instance for each such value,
representing the globally unique template parameter object to which the
template parameter refers.

No IR generation support yet; that will follow in a separate patch.

show more ...

Properly track whether a variable is constant-initialized.

This fixes miscomputation of __builtin_constant_evaluated in the
initializer of a variable that's not usable in constant expressions, but
i

Properly track whether a variable is constant-initialized.

This fixes miscomputation of __builtin_constant_evaluated in the
initializer of a variable that's not usable in constant expressions, but
is readable when constant-folding.

If evaluation of a constant initializer fails, we throw away the
evaluated result instead of keeping it as a non-constant-initializer
value for the variable, because it might not be a correct value.
To avoid regressions for initializers that are foldable but not formally
constant initializers, we now try constant-evaluating some globals in
C++ twice: once to check for a constant initializer (in an mode where
is_constannt_evaluated returns true) and again to determine the runtime
value if the initializer is not a constant initializer.

show more ...

[Fixed Point] Add fixed-point to floating point cast types and consteval.

Reviewed By: leonardchan

Differential Revision: https://reviews.llvm.org/D86631

Canonicalize declaration pointers when forming APValues.

References to different declarations of the same entity aren't different
values, so shouldn't have different representations.

Recommit of e6

Canonicalize declaration pointers when forming APValues.

References to different declarations of the same entity aren't different
values, so shouldn't have different representations.

Recommit of e6393ee813178e9d3306b8e3c6949a4f32f8a2cb, most recently
reverted in 9a33f027ac7d73e14ae287e78ab554142d1cbc8f due to a bug caused
by ObjCInterfaceDecls not propagating availability attributes along
their redeclaration chains; that bug was fixed in
e2d4174e9c66251d1b408234b53f53d0903c0285.

show more ...

Revert "Canonicalize declaration pointers when forming APValues."

This reverts commit 9dcd96f728863d40d6f5922ed52732fdd728fb5f.

See https://crbug.com/1134762.

Canonicalize declaration pointers when forming APValues.

References to different declarations of the same entity aren't different
values, so shouldn't have different representations.

Recommit of e6

Canonicalize declaration pointers when forming APValues.

References to different declarations of the same entity aren't different
values, so shouldn't have different representations.

Recommit of e6393ee813178e9d3306b8e3c6949a4f32f8a2cb with fixed handling
for weak declarations. We now look for attributes on the most recent
declaration when determining whether a declaration is weak. (Second
recommit with further fixes for mishandling of weak declarations. Our
behavior here is fundamentally unsound -- see PR47663 -- but this
approach attempts to not make things worse.)

show more ...

Remove dead branch identified by @rsmith on post-commit for D88236

[PR47636] Fix tryEmitPrivate to handle non-constantarraytypes

As mentioned in the bug report, tryEmitPrivate chokes on the
MaterializeTemporaryExpr in the reproducers, since it assumes that if
there

[PR47636] Fix tryEmitPrivate to handle non-constantarraytypes

As mentioned in the bug report, tryEmitPrivate chokes on the
MaterializeTemporaryExpr in the reproducers, since it assumes that if
there are elements, than it must be a ConstantArrayType. However, the
MaterializeTemporaryExpr (which matches exactly the AST when it is NOT a
global/static) has an incomplete array type.

This changes the section where the number-of-elements is non-zero to
properly handle non-CAT types by just extracting it as an array type
(since all we needed was the element type out of it).

show more ...

[c++20] consteval functions don't get vtable slots.

For the Itanium C++ ABI, this implements the rule added in
https://github.com/itanium-cxx-abi/cxx-abi/pull/83

For the MS C++ ABI, this implements

[c++20] consteval functions don't get vtable slots.

For the Itanium C++ ABI, this implements the rule added in
https://github.com/itanium-cxx-abi/cxx-abi/pull/83

For the MS C++ ABI, this implements the direction that seemed most
plausible based on personal correspondence with MSVC developers, but is
subject to change as they decide their ABI rule.

show more ...

attempt to fix failing buildbots after 3bab88b7baa20b276faaee0aa7ca87f636c91877

Prevent IR-gen from emitting consteval declarations

Summary: with this patch instead of emitting calls to consteval f

attempt to fix failing buildbots after 3bab88b7baa20b276faaee0aa7ca87f636c91877

Prevent IR-gen from emitting consteval declarations

Summary: with this patch instead of emitting calls to consteval function. the IR-gen will emit a store of the already computed result.

show more ...