Commit Graph

2198 Commits

Author SHA1 Message Date
Zequan Wu 15a3ae1ab1 [Clang] Add __STDCPP_THREADS__ to standard predefine macros
According to https://eel.is/c++draft/cpp.predefined#2.6, `__STDCPP_THREADS__` is a predefined macro.

Differential Revision: https://reviews.llvm.org/D91747
2020-11-22 16:05:53 -08:00
Aaron Puchert 825f80e111 [Sema] Introduce function reference conversion, NFC
Technically 'noexcept' isn't a qualifier, so this should be a separate conversion.

Also make the test a pure frontend test.

Reviewed By: rsmith

Differential Revision: https://reviews.llvm.org/D67112
2020-11-22 20:51:57 +01:00
Erich Keane a72f11ee20 Fix a pair of tests that would fail on a win32 box
The tests don't specify a triple in some cases, since they shouldn't be
necessary, so I've updated the tests to detect via macro when they are
running on win32 to give the slightly altered diagnostic.
2020-11-17 14:28:52 -08:00
Erich Keane 6976fef05b Update 'note-candiate' functions to skip lambda-conversion-op-overloads
In the wake of https://reviews.llvm.org/D89559, we discovered that a
couple of tests (the ones modified below to have additional triple
versions) would fail on Win32, for 1 of two reasons.  We seem to not
have a win32 buildbot anymore, so the triple is to make sure this
doesn't get broken in the future.

First, two of the three 'note-candidate' functions weren't appropriately
skipping the remaining conversion functions.

Second, in 1 situation (note surrogate candidates) we actually print the
type of the conversion operator.  The two tests that ran into that
needed updating to make sure it printed the proper one in the win32
case.
2020-11-17 05:49:31 -08:00
CJ Johnson 69cd776e1e [CodeGen] Apply 'nonnull' and 'dereferenceable(N)' to 'this' pointer
arguments.

* Adds 'nonnull' and 'dereferenceable(N)' to 'this' pointer arguments
* Gates 'nonnull' on -f(no-)delete-null-pointer-checks
* Introduces this-nonnull.cpp and microsoft-abi-this-nullable.cpp tests to
  explicitly test the behavior of this change
* Refactors hundreds of over-constrained clang tests to permit these
  attributes, where needed
* Updates Clang12 patch notes mentioning this change

Reviewed-by: rsmith, jdoerfert

Differential Revision: https://reviews.llvm.org/D17993
2020-11-16 17:39:17 -08:00
Aaron Puchert dea31f135c Consistent spelling in diagnostics: {l,r}value instead of {l,r}-value
As Richard Smith pointed out in the review of D90123, both the C and C++
standard call it lvalue and rvalue, so let's stick to the same spelling
in Clang.
2020-11-15 18:05:11 +01:00
Aaron Puchert 6f84779674 [Sema] Improve notes for value category mismatch in overloading
When an overloaded member function has a ref-qualifier, like:

class X {
    void f() &&;
    void f(int) &;
};

we would print strange notes when the ref-qualifier doesn't fit the value
category:

X x;
x.f();
X().f(0);

would both print a note "no known conversion from 'X' to 'X' for object
argument" on their relevant overload instead of pointing out the
mismatch in value category.

At first I thought the solution is easy: just use the FailureKind member
of the BadConversionSequence struct. But it turns out that we weren't
properly setting this for function arguments. So I went through
TryReferenceInit to make sure we're doing that right, and found a number
of notes in the existing tests that improved as well.

Fixes PR47791.

Reviewed By: rsmith

Differential Revision: https://reviews.llvm.org/D90123
2020-11-15 18:05:11 +01:00
Richard Smith 5f12f4ff90 Suppress printing of inline namespace names in diagnostics by default,
except where they are necessary to disambiguate the target.

This substantially improves diagnostics from the standard library,
which are otherwise full of `::__1::` noise.
2020-11-11 15:05:51 -08:00
Yang Fan 703038b35a [Sema] Fix volatile check when testing if a return object can be implicitly moved
In C++11 standard, to become implicitly movable, the expression in return
statement should be a non-volatile automatic object. CWG1579 changed the rule
to require that the expression only needs to be an automatic object. C++14
standard and C++17 standard kept this rule unchanged. C++20 standard changed
the rule back to require the expression be a non-volatile automatic object.
This should be a typo in standards, and VD should be non-volatile.

Differential Revision: https://reviews.llvm.org/D88295
2020-11-10 15:11:07 -05:00
Richard Smith 2177e4555a PR47861: Expand dangling reference warning to look through copy
construction, and to assume that assignment operators return *this.
2020-10-30 10:19:50 -07:00
Richard Smith 09abecef7b PR48002: Fix injection of elaborated-type-specifiers within local
classes into the enclosing block scope.

We weren't properly detecting whether the name would be injected into a
block scope in the case where it was lexically declared in a local
class.
2020-10-28 14:29:45 -07:00
Melanie Blower 2e204e2391 [clang] Enable support for #pragma STDC FENV_ACCESS
Reviewers: rjmccall, rsmith, sepavloff

Differential Revision: https://reviews.llvm.org/D87528
2020-10-25 06:46:25 -07:00
Richard Smith f81f09ba89 [c++20] For P0732R2: Support string literal operator templates. 2020-10-25 00:34:15 -07:00
Richard Smith 7b3515880c For P0732R2, P1907R1: ensure that template parameter objects don't refer
to disallowed objects or have non-constant destruction.
2020-10-24 22:11:43 -07:00
Richard Smith cb9b9842d3 PR47954 / DR2126: permit temporary objects that are lifetime-extended by
variables that are usable in constant expressions to themselves be
usable in constant expressions.
2020-10-23 14:29:18 -07:00
Richard Smith e97e9851b2 [c++20] For P0732R2: permit class template argument deduction for non-type template parameters. 2020-10-21 15:03:22 -07:00
Richard Smith caf30e7f03 [c++20] For P0732R2: Give class NTTPs the proper type when examined with 'decltype'.
This requires that we track enough information to determine the original
type of the parameter in a substituted non-type template parameter, to
distinguish the reference-to-class case from the class case.
2020-10-21 14:15:54 -07:00
Richard Smith ba4768c966 [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.
2020-10-21 13:21:41 -07:00
Richard Smith 552c6c2328 PR44406: Follow behavior of array bound constant folding in more recent versions of GCC.
Old GCC used to aggressively fold VLAs to constant-bound arrays at block
scope in GNU mode. That's non-conforming, and more modern versions of
GCC only do this at file scope. Update Clang to do the same.

Also promote the warning for this from off-by-default to on-by-default
in all cases; more recent versions of GCC likewise warn on this by
default.

This is still slightly more permissive than GCC, as pointed out in
PR44406, as we still fold VLAs to constant arrays in structs, but that
seems justifiable given that we don't support VLA-in-struct (and don't
intend to ever support it), but GCC does.

Differential Revision: https://reviews.llvm.org/D89523
2020-10-16 14:34:35 -07:00
Richard Smith f7f2e4261a PR47805: Use a single object for a function parameter in the caller and
callee in constant evaluation.

We previously made a deep copy of function parameters of class type when
passing them, resulting in the destructor for the parameter applying to
the original argument value, ignoring any modifications made in the
function body. This also meant that the 'this' pointer of the function
parameter could be observed changing between the caller and the callee.

This change completely reimplements how we model function parameters
during constant evaluation. We now model them roughly as if they were
variables living in the caller, albeit with an artificially reduced
scope that covers only the duration of the function call, instead of
modeling them as temporaries in the caller that we partially "reparent"
into the callee at the point of the call. This brings some minor
diagnostic improvements, as well as significantly reduced stack usage
during constant evaluation.
2020-10-14 17:43:51 -07:00
Richard Smith 69f7c006ff Revert "PR47805: Use a single object for a function parameter in the caller and"
Breaks a clangd unit test.

This reverts commit 8f8b9f2cca.
2020-10-13 19:32:03 -07:00
Richard Smith 8f8b9f2cca PR47805: Use a single object for a function parameter in the caller and
callee in constant evaluation.

We previously made a deep copy of function parameters of class type when
passing them, resulting in the destructor for the parameter applying to
the original argument value, ignoring any modifications made in the
function body. This also meant that the 'this' pointer of the function
parameter could be observed changing between the caller and the callee.

This change completely reimplements how we model function parameters
during constant evaluation. We now model them roughly as if they were
variables living in the caller, albeit with an artificially reduced
scope that covers only the duration of the function call, instead of
modeling them as temporaries in the caller that we partially "reparent"
into the callee at the point of the call. This brings some minor
diagnostic improvements, as well as significantly reduced stack usage
during constant evaluation.
2020-10-13 18:50:46 -07:00
Richard Smith ab870f3030 Revert "PR47805: Use a single object for a function parameter in the caller and"
The buildbots are displeased.

This reverts commit 8d03a972ce.
2020-10-13 15:59:00 -07:00
Richard Smith 8d03a972ce PR47805: Use a single object for a function parameter in the caller and
callee in constant evaluation.

We previously made a deep copy of function parameters of class type when
passing them, resulting in the destructor for the parameter applying to
the original argument value, ignoring any modifications made in the
function body. This also meant that the 'this' pointer of the function
parameter could be observed changing between the caller and the callee.

This change completely reimplements how we model function parameters
during constant evaluation. We now model them roughly as if they were
variables living in the caller, albeit with an artificially reduced
scope that covers only the duration of the function call, instead of
modeling them as temporaries in the caller that we partially "reparent"
into the callee at the point of the call. This brings some minor
diagnostic improvements, as well as significantly reduced stack usage
during constant evaluation.
2020-10-13 15:45:04 -07:00
Richard Smith 913f600566 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 e6393ee813, most recently
reverted in 9a33f027ac due to a bug caused
by ObjCInterfaceDecls not propagating availability attributes along
their redeclaration chains; that bug was fixed in
e2d4174e9c.
2020-10-12 19:32:57 -07:00
Arthur Eubanks 9a33f027ac Revert "Canonicalize declaration pointers when forming APValues."
This reverts commit 9dcd96f728.

See https://crbug.com/1134762.
2020-10-12 12:37:24 -07:00
Mark de Wever 0ce6d6b46e [Sema] List conversion validate character array.
The function `TryListConversion` didn't properly validate the following
part of the standard:

    Otherwise, if the parameter type is a character array [... ]
    and the initializer list has a single element that is an
    appropriately-typed string literal (8.5.2 [dcl.init.string]), the
    implicit conversion sequence is the identity conversion.

This caused the following call to `f()` to be ambiguous.
    void f(int(&&)[1]);
    void f(unsigned(&&)[1]);

    void g(unsigned i) {
      f({i});
    }

This issue only occurs when the initializer list had one element.

Differential Revision: https://reviews.llvm.org/D87561
2020-10-03 14:33:28 +02:00
Aaron Ballman 538762fef0 Better diagnostics for anonymous bit-fields with attributes or an initializer.
The current C++ grammar allows an anonymous bit-field with an attribute,
but this is ambiguous (the attribute in that case could appertain to the
type instead of the bit-field). The current thinking in the Core Working
Group is that it's better to disallow attributes in that position at the
grammar level so that the ambiguity resolves in favor of applying to the
type.

During discussions about the behavior of the attribute, the Core Working
Group also felt it was better to disallow anonymous bit-fields from
specifying a default member initializer.

This implements both sets of related grammar changes.
2020-09-29 16:32:20 -04:00
Richard Smith 9dcd96f728 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 e6393ee813 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.)
2020-09-27 19:05:26 -07:00
Leonard Chan 15d94a7d0f Revert "Canonicalize declaration pointers when forming APValues."
This reverts commit 905b9ca26c.

Reverting because this strips `weak` attributes off function
declarations, leading to the linker error we see at
https://ci.chromium.org/p/fuchsia/builders/ci/clang_toolchain.fuchsia-arm64-debug-subbuild/b8868932035091473008.

See https://reviews.llvm.org/rG905b9ca26c94 for reproducer details.
2020-09-22 17:40:53 -07:00
Richard Smith aa769358d8 [c++20] Consistent with the intent to allow all plausible types in
non-type template parameters, permit vector types.
2020-09-20 23:09:26 -07:00
Richard Smith 0cd73dbe2c [c++20] For P1907R1: Add checking for structural types for non-type
template parameters.

No support for the new kinds of non-type template argument yet.

This is not entirely NFC for prior language modes: we have historically
incorrectly accepted rvalue references as the types of non-type template
parameters. Such invalid code is now rejected.
2020-09-20 20:20:52 -07:00
Richard Smith 905b9ca26c 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 e6393ee813 with fixed
handling for weak declarations. We now look for attributes on the most
recent declaration when determining whether a declaration is weak.
2020-09-16 18:11:18 -07:00
Nico Weber 7b0332389a Revert "Canonicalize declaration pointers when forming APValues."
This reverts commit e6393ee813.
It breaks Wunreachable for weak attributes, see
http://lists.llvm.org/pipermail/cfe-commits/Week-of-Mon-20200831/336645.html
2020-09-04 10:13:28 -04:00
Richard Smith e6393ee813 Canonicalize declaration pointers when forming APValues.
References to different declarations of the same entity aren't different
values, so shouldn't have different representations.
2020-09-03 15:35:12 -07:00
Haojian Wu 09e7fe9859 [AST][RecoveryAST] Preserve the type by default for recovery expression.
Differential Revision: https://reviews.llvm.org/D82657
2020-08-24 14:28:28 +02:00
Richard Smith 6f33936719 Explain why the array bound is non-constant in VLA diagnostics.
In passing, also use a more precise diagnostic to explain why an
expression is not an ICE if it's not of integral type.
2020-08-19 15:45:51 -07:00
Mark de Wever fef2607124 [Sema] Use the proper cast for a fixed bool enum.
When casting an enumerate with a fixed bool type the casting should use
an IntegralToBoolean instead of an IntegralCast as is required per Core
Issue 2338.

Fixes PR47055: Incorrect codegen for enum with bool underlying type

Differential Revision: https://reviews.llvm.org/D85612
2020-08-16 18:40:08 +02:00
Erich Keane e704aa4f25 DR2303: Prefer 'nearer' base classes during template deduction.
DR2303 fixes the case where the derived-base match for template
deduction is ambiguous if a base-of-base ALSO matches. The canonical
example (as shown in the test) is just like the MSVC implementation of
std::tuple.

This fixes a fairly sizable issue, where if a user inherits from
std::tuple on Windows (with the MS STL), they cannot use that type to
call a function that takes std::tuple.

Differential Revision: https://reviews.llvm.org/D84048
2020-07-31 05:39:55 -07:00
Richard Smith a648834313 PR46729: Reject explicit and partial specializations with C linkage. 2020-07-29 17:44:32 -07:00
Bruno Ricci eb10b065f2
[clang] Pass the NamedDecl* instead of the DeclarationName into many diagnostics.
Background:
-----------
There are two related argument types which can be sent into a diagnostic to
display the name of an entity: DeclarationName (ak_declarationname) or
NamedDecl* (ak_nameddecl) (there is also ak_identifierinfo for
IdentifierInfo*, but we are not concerned with it here).

A DeclarationName in a diagnostic will just be streamed to the output,
which will directly result in a call to DeclarationName::print.

A NamedDecl* in a diagnostic will also ultimately result in a call to
DeclarationName::print, but with two customisation points along the way:

The first customisation point is NamedDecl::getNameForDiagnostic which is
overloaded by FunctionDecl, ClassTemplateSpecializationDecl and
VarTemplateSpecializationDecl to print the template arguments, if any.

The second customisation point is NamedDecl::printName. By default it just
streams the stored DeclarationName into the output but it can be customised
to provide a user-friendly name for an entity. It is currently overloaded by
DecompositionDecl and MSGuidDecl.

What this patch does:
---------------------
For many diagnostics a DeclarationName is used instead of the NamedDecl*.
This bypasses the two customisation points mentioned above. This patches fix
this for diagnostics in Sema.cpp, SemaCast.cpp, SemaChecking.cpp, SemaDecl.cpp,
SemaDeclAttr.cpp, SemaDecl.cpp, SemaOverload.cpp and SemaStmt.cpp.

I have only modified diagnostics where I could construct a test-case which
demonstrates that the change is appropriate (either with this patch or the next
one).

Reviewed By: erichkeane, aaron.ballman

Differential Revision: https://reviews.llvm.org/D84656
2020-07-28 10:30:35 +01:00
Bruno Ricci acf3bdc283
[clang][NFC] Tests showing the problems with some uses of NamedDecl::getDeclName in diagnostics, SemaOverload.cpp+SemaStmt.cpp part 2020-07-18 20:44:06 +01:00
Bruno Ricci be8e5fee91
[clang][NFC] Tests showing the problems with some uses of NamedDecl::getDeclName in diagnostics, SemaExpr.cpp part 2020-07-18 20:39:16 +01:00
Richard Smith 00068c452a Improve diagnostics for constant evaluation that fails because a
variable's initializer is not known.

The hope is that a better diagnostic for this case will reduce the rate
at which duplicates of non-bug PR41093 are reported.
2020-07-08 18:14:23 -07:00
Richard Smith d1446017f3 DR458: Search template parameter scopes in the right order.
C++ unqualified name lookup searches template parameter scopes
immediately after finishing searching the entity the parameters belong
to. (Eg, for a class template, you search the template parameter scope
after looking in that class template and its base classes and before
looking in the scope containing the class template.) This is complicated
by the fact that scope lookup within a template parameter scope looks in
a different sequence of places prior to reaching the end of the
declarator-id in the template declaration.

We used to approximate the proper lookup rule with a hack in the scope /
decl context walk inside name lookup. Now we instead compute the lookup
parent for each template parameter scope.

In order to get this right, we now make sure to enter a distinct Scope
for each template parameter scope, and make sure to re-enter the
enclosing class scopes properly when handling delay-parsed regions
within a class.
2020-06-23 17:14:33 -07:00
Richard Smith 02fccc26cf Revert "DR458: Search template parameter scopes in the right order."
We weren't re-entering template scopes in the right order, causing this
to break self-host with -fdelayed-template-parsing.

This reverts commit 237c2a23b6.
2020-06-16 23:53:44 -07:00
Richard Smith 237c2a23b6 DR458: Search template parameter scopes in the right order.
C++ unqualified name lookup searches template parameter scopes
immediately after finishing searching the entity the parameters belong
to. (Eg, for a class template, you search the template parameter scope
after looking in that class template and its base classes and before
looking in the scope containing the class template.) This is complicated
by the fact that scope lookup within a template parameter scope looks in
a different sequence of places prior to reaching the end of the
declarator-id in the template declaration.

We used to approximate the proper lookup rule with a hack in the scope /
decl context walk inside name lookup. Now we instead compute the lookup
parent for each template parameter scope. This gets the right answer and
as a bonus is substantially simpler and more uniform.

In order to get this right, we now make sure to enter a distinct Scope
for each template parameter scope. (The fact that we didn't before was
already a bug, but not really observable most of the time, since
template parameters can't shadow each other.)
2020-06-16 19:41:14 -07:00
Bruno Ricci f13d704a50
[clang][NFC] Mark CWG 1443 (Default arguments and non-static data members)...
...as done. This is a NAD which has always been implemented correctly.
2020-06-13 13:59:54 +01:00
Bruno Ricci eb614db0a0
[clang][NFC] Mark CWG 974 and 1814 (default argument in a...
...lambda-expression) as done. They have been allowed since at least clang 3.3.
2020-06-13 13:49:07 +01:00
Haojian Wu 58ea1059df [AST][RecoveryExpr] Build recovery expressions by default for C++.
Reland https://reviews.llvm.org/D76696
All known crashes have been fixed, another attemption.

We have rolled out this to all internal users for a while, didn't see
big issues, we consider it is stable enough.

Reviewed By: sammccall

Subscribers: rsmith, hubert.reinterpretcast, ebevhan, jkorous, arphaman, kadircet, usaxena95, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D78350
2020-06-12 15:21:38 +02:00