29 Commits

Author SHA1 Message Date
Fangrui Song
57f42a8765 Revert "[clang] Substitute alias templates from correct context (#75069)"
This reverts commit dbf67ea1d334d2114fe49701a8f4b8afd536e39f.

It caused spurious "out-of-line definition of 'operator=' does not match
any declaration in" error.
https://github.com/llvm/llvm-project/pull/75069#issuecomment-1856581259
2023-12-14 14:57:15 -08:00
Mariya Podchishchaeva
dbf67ea1d3
[clang] Substitute alias templates from correct context (#75069)
Current context set to where alias was met, not where it is declared
caused incorrect access check in case alias referenced private members
of the parent class.
This is a recommit of 6b1aa31 with a slight modification in order to fix
reported regression.

Fixes https://github.com/llvm/llvm-project/issues/41693
2023-12-13 08:50:43 +01:00
Podchishchaeva, Mariya
565dddec63 Revert "[clang] Substitute alias templates from correct context (#74335)"
It was reported in the PR that commit caused clang giving errors for
code previously considered valid.
This reverts commit 6b1aa319754e76366edd88e10034e0539710d946.
2023-12-06 08:49:17 -08:00
Mariya Podchishchaeva
6b1aa31975
[clang] Substitute alias templates from correct context (#74335)
Current context set to where alias was met, not where it is declared
caused incorrect access check in case alias referenced private members
of the parent class.

Fixes https://github.com/llvm/llvm-project/issues/41693
2023-12-06 11:14:17 +01:00
Aaron Ballman
84a3aadf0f Diagnose use of VLAs in C++ by default
Reapplication of 7339c0f782d5c70e0928f8991b0c05338a90c84c with a fix
for a crash involving arrays without a size expression.

Clang supports VLAs in C++ as an extension, but we currently only warn
on their use when you pass -Wvla, -Wvla-extension, or -pedantic.
However, VLAs as they're expressed in C have been considered by WG21
and rejected, are easy to use accidentally to the surprise of users
(e.g., https://ddanilov.me/default-non-standard-features/), and they
have potential security implications beyond constant-size arrays
(https://wiki.sei.cmu.edu/confluence/display/c/ARR32-C.+Ensure+size+arguments+for+variable+length+arrays+are+in+a+valid+range).
C++ users should strongly consider using other functionality such as
std::vector instead.

This seems like sufficiently compelling evidence to warn users about
VLA use by default in C++ modes. This patch enables the -Wvla-extension
diagnostic group in C++ language modes by default, and adds the warning
group to -Wall in GNU++ language modes. The warning is still opt-in in
C language modes, where support for VLAs is somewhat less surprising to
users.

RFC: https://discourse.llvm.org/t/rfc-diagnosing-use-of-vlas-in-c/73109
Fixes https://github.com/llvm/llvm-project/issues/62836
Differential Revision: https://reviews.llvm.org/D156565
2023-10-20 13:10:03 -04:00
Aaron Ballman
f5043f46c0 Revert "Diagnose use of VLAs in C++ by default"
This reverts commit 7339c0f782d5c70e0928f8991b0c05338a90c84c.

Breaks bots:
https://lab.llvm.org/buildbot/#/builders/139/builds/51875
https://lab.llvm.org/buildbot/#/builders/164/builds/45262
2023-10-20 10:00:18 -04:00
Aaron Ballman
7339c0f782 Diagnose use of VLAs in C++ by default
Clang supports VLAs in C++ as an extension, but we currently only warn
on their use when you pass -Wvla, -Wvla-extension, or -pedantic.
However, VLAs as they're expressed in C have been considered by WG21
and rejected, are easy to use accidentally to the surprise of users
(e.g., https://ddanilov.me/default-non-standard-features/), and they
have potential security implications beyond constant-size arrays
(https://wiki.sei.cmu.edu/confluence/display/c/ARR32-C.+Ensure+size+arguments+for+variable+length+arrays+are+in+a+valid+range).
C++ users should strongly consider using other functionality such as
std::vector instead.

This seems like sufficiently compelling evidence to warn users about
VLA use by default in C++ modes. This patch enables the -Wvla-extension
diagnostic group in C++ language modes by default, and adds the warning
group to -Wall in GNU++ language modes. The warning is still opt-in in
C language modes, where support for VLAs is somewhat less surprising to
users.

RFC: https://discourse.llvm.org/t/rfc-diagnosing-use-of-vlas-in-c/73109
Fixes https://github.com/llvm/llvm-project/issues/62836
Differential Revision: https://reviews.llvm.org/D156565
2023-10-20 09:50:21 -04:00
Muhammad Usman Shahid
76476efd68 Rewording "static_assert" diagnostics
This patch rewords the static assert diagnostic output. Failing a
_Static_assert in C should not report that static_assert failed. This
changes the wording to be more like GCC and uses "static assertion"
when possible instead of hard coding the name. This also changes some
instances of 'static_assert' to instead be based on the token in the
source code.

Differential Revision: https://reviews.llvm.org/D129048
2022-07-25 07:22:54 -04:00
Erich Keane
1da3119025 Revert "Rewording the "static_assert" to static assertion"
Looks like we again are going to have problems with libcxx tests that
are overly specific in their dependency on clang's diagnostics.

This reverts commit 6542cb55a3eb115b1c3592514590a19987ffc498.
2022-07-21 06:40:14 -07:00
Muhammad Usman Shahid
6542cb55a3 Rewording the "static_assert" to static assertion
This patch is basically the rewording of the static assert statement's
output(error) on screen after failing. Failing a _Static_assert in C
should not report that static_assert failed. It’d probably be better to
reword the diagnostic to be more like GCC and say “static assertion”
failed in both C and C++.

consider a c file having code

_Static_assert(0, "oh no!");

In clang the output is like:

<source>:1:1: error: static_assert failed: oh no!
_Static_assert(0, "oh no!");
^              ~
1 error generated.
Compiler returned: 1

Thus here the "static_assert" is not much good, it will be better to
reword it to the "static assertion failed" to more generic. as the gcc
prints as:

<source>:1:1: error: static assertion failed: "oh no!"
    1 | _Static_assert(0, "oh no!");
          | ^~~~~~~~~~~~~~
          Compiler returned: 1

The above can also be seen here. This patch is about rewording
the static_assert to static assertion.

Differential Revision: https://reviews.llvm.org/D129048
2022-07-21 06:34:14 -07:00
Mitch Phillips
041d4012e4 Revert "Rewording "static_assert" diagnostics"
This reverts commit b7e77ff25fb2412f6ab6d6cc756666b0e2f97bd3.

Reason: Broke sanitizer builds bots + libcxx. 'static assertion
expression is not an integral constant expression'. More details
available in the Phabricator review: https://reviews.llvm.org/D129048
2022-07-14 10:59:20 -07:00
Muhammad Usman Shahid
b7e77ff25f Rewording "static_assert" diagnostics
This patch rewords the static assert diagnostic output. Failing a
_Static_assert in C should not report that static_assert failed. This
changes the wording to be more like GCC and uses "static assertion"
when possible instead of hard coding the name. This also changes some
instances of 'static_assert' to instead be based on the token in the
source code.

Differential Revision: https://reviews.llvm.org/D129048
2022-07-14 07:47:37 -04:00
David Blaikie
aee4925507 Recommit: Compress formatting of array type names (int [4] -> int[4])
Based on post-commit review discussion on
2bd84938470bf2e337801faafb8a67710f46429d with Richard Smith.

Other uses of forcing HasEmptyPlaceHolder to false seem OK to me -
they're all around pointer/reference types where the pointer/reference
token will appear at the rightmost side of the left side of the type
name, so they make nested types (eg: the "int" in "int *") behave as
though there is a non-empty placeholder (because the "*" is essentially
the placeholder as far as the "int" is concerned).

This was originally committed in 277623f4d5a672d707390e2c3eaf30a9eb4b075c

Reverted in f9ad1d1c775a8e264bebc15d75e0c6e5c20eefc7 due to breakages
outside of clang - lldb seems to have some strange/strong dependence on
"char [N]" versus "char[N]" when printing strings (not due to that name
appearing in DWARF, but probably due to using clang to stringify type
names) that'll need to be addressed, plus a few other odds and ends in
other subprojects (clang-tools-extra, compiler-rt, etc).
2021-10-21 11:34:43 -07:00
David Blaikie
f9ad1d1c77 Revert "Compress formatting of array type names (int [4] -> int[4])"
Looks like lldb has some issues with this - somehow it causes lldb to
treat a "char[N]" type as an array of chars (prints them out
individually) but a "char [N]" is printed as a string. (even though the
DWARF doesn't have this string in it - it's something to do with the
string lldb generates for itself using clang)

This reverts commit 277623f4d5a672d707390e2c3eaf30a9eb4b075c.
2021-10-14 14:49:25 -07:00
David Blaikie
277623f4d5 Compress formatting of array type names (int [4] -> int[4])
Based on post-commit review discussion on
2bd84938470bf2e337801faafb8a67710f46429d with Richard Smith.

Other uses of forcing HasEmptyPlaceHolder to false seem OK to me -
they're all around pointer/reference types where the pointer/reference
token will appear at the rightmost side of the left side of the type
name, so they make nested types (eg: the "int" in "int *") behave as
though there is a non-empty placeholder (because the "*" is essentially
the placeholder as far as the "int" is concerned).
2021-10-14 14:23:32 -07:00
Richard Smith
b23c5e8c3d [c++20] Implement P0846R0: allow (ADL-only) calls to template-ids whose
template name is not visible to unqualified lookup.

In order to support this without a severe degradation in our ability to
diagnose typos in template names, this change significantly restructures
the way we handle template-id-shaped syntax for which lookup of the
template name finds nothing.

Instead of eagerly diagnosing an undeclared template name, we now form a
placeholder template-name representing a name that is known to not find
any templates. When the parser sees such a name, it attempts to
disambiguate whether we have a less-than comparison or a template-id.
Any diagnostics or typo-correction for the name are delayed until its
point of use.

The upshot should be a small improvement of our diagostic quality
overall: we now take more syntactic context into account when trying to
resolve an undeclared identifier on the left hand side of a '<'. In
fact, this works well enough that the backwards-compatible portion (for
an undeclared identifier rather than a lookup that finds functions but
no function templates) is enabled in all language modes.

llvm-svn: 360308
2019-05-09 03:31:27 +00:00
Brian Gesiak
7dda73a223 [SemaCXX] Fix ICE for unexpanded parameter pack
Summary:
The documentation for RecursiveASTVisitor::TraverseDecl states that the
Decl being traversed may be null. In fact, this is the case when a
CXXCatchStmt with no exception decl is traversed. Because the visitor
for diagnosing unexpanded parameter packs does not check for null, it
ends up crashing when it attempts to call the Decl::isParameterPack
method on a null Decl pointer.

Add a null check to prevent an ICE, and a test case that would crash
otherwise. Also, because the test requires C++ exceptions and C++14,
change the test parameters for the entire test file. (Alternatively, I
thought about adding a new test file, but went with this approach for my
own convenience.)

Co-authored-by: Andreas Molzer <andreas.molzer@gmx.de>
Co-authored-by: Mara Bos <m-ou.se@m-ou.se>

Reviewers: rsmith

Reviewed By: rsmith

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D56271

llvm-svn: 350501
2019-01-07 03:25:59 +00:00
Erik Pilkington
ba88e21f8c [Sema] Make sure we substitute an instantiation-dependent default template argument
Fixes llvm.org/PR39623

Differential revision: https://reviews.llvm.org/D54414

llvm-svn: 346709
2018-11-12 21:31:06 +00:00
Richard Smith
3cbf3f1f59 Push alias-declarations and alias-template declarations into scope even if
they're redeclarations. This is necessary in order for name lookup to correctly
find the most recent declaration of the name (which affects default template
argument lookup and cross-module merging, among other things).

llvm-svn: 275612
2016-07-15 20:53:25 +00:00
David Majnemer
16a74704c9 [AST] Perform additional canonicalization for DependentSizedArrayType
We treated DependentSizedArrayTypes with the same element type but
differing size expressions as equivalently canonical.  This would lead
to bizarre behavior during template instantiation.

This fixes PR24212.

llvm-svn: 243093
2015-07-24 05:54:19 +00:00
Richard Smith
88fe69ce21 DR1909: Diagnose all invalid cases of a class member sharing its name with the class.
llvm-svn: 241425
2015-07-06 01:45:27 +00:00
Ismail Pazarbasi
025f428c73 Replace "can not" with "cannot" in diagnostics messages.
llvm-svn: 203302
2014-03-07 22:36:23 +00:00
David Majnemer
f703b588b8 Implement DR577
DR18 previously forebode typedefs to be used as parameter types if they
were of type 'void'.  DR577 allows 'void' to be used as a function
parameter type regardless from where it came.

llvm-svn: 201631
2014-02-19 03:00:56 +00:00
Enea Zaffanella
29e1c4b03e Fixed an assertion failure triggered by invalid code.
Set invalid type of declarator after emitting error diagnostics,
so that it won't be later considered when instantiating the template.
Added test5_inst in test/SemaCXX/condition.cpp for non-regression.

llvm-svn: 172201
2013-01-11 14:34:39 +00:00
Richard Smith
72249ba945 PR12647: An alias template instantiation which occurs in a SFINAE context is
itself a SFINAE context.

llvm-svn: 155621
2012-04-26 07:24:08 +00:00
Richard Smith
c5b0552055 Fix parsing of type-specifier-seq's. Types are syntactically allowed to be
defined here, but not semantically, so

  new struct S {};

is always ill-formed, even if there is a struct S in scope.

We also had a couple of bugs in ParseOptionalTypeSpecifier caused by it being
under-loved (due to it only being used in a few places) so merge it into
ParseDeclarationSpecifiers with a new DeclSpecContext. To avoid regressing, this
required improving ParseDeclarationSpecifiers' diagnostics in some cases. This
also required teaching ParseSpecifierQualifierList about constexpr... which
incidentally fixes an issue where we'd allow the constexpr specifier in other
bad places.

llvm-svn: 152549
2012-03-12 07:56:15 +00:00
Richard Smith
63168c7533 PR11684, core issue 1417:
o Correct the handling of the restrictions on usage of cv-qualified and
  ref-qualified function types.
o Fix a bug where such types were rejected in template type parameter default
  arguments, due to such arguments not being treated as a template type arg
  context.
o Remove the ExtWarn for usage of such types as template arguments; that was
  a standard defect, not a GCC extension.
o Improve the wording and unify the code for diagnosing cv-qualifiers with the
  code for diagnosing ref-qualifiers.

llvm-svn: 150244
2012-02-10 11:05:11 +00:00
Richard Smith
9ca5c42582 Update all tests other than Driver/std.cpp to use -std=c++11 rather than
-std=c++0x. Patch by Ahmed Charles!

llvm-svn: 141900
2011-10-13 22:29:44 +00:00
Richard Smith
3f1b5d077b Implement support for C++0x alias templates.
llvm-svn: 130953
2011-05-05 21:57:07 +00:00