Specifically, the following features are not included in this commit:
- any sort of capturing within generic lambdas
- generic lambdas within template functions and nested
within other generic lambdas
- conversion operator for captureless lambdas
- ensuring all visitors are generic lambda aware
(Although I have gotten some useful feedback on my patches of the above and will be incorporating that as I submit those patches for commit)
As an example of what compiles through this commit:
template <class F1, class F2>
struct overload : F1, F2 {
using F1::operator();
using F2::operator();
overload(F1 f1, F2 f2) : F1(f1), F2(f2) { }
};
auto Recursive = [](auto Self, auto h, auto ... rest) {
return 1 + Self(Self, rest...);
};
auto Base = [](auto Self, auto h) {
return 1;
};
overload<decltype(Base), decltype(Recursive)> O(Base, Recursive);
int num_params = O(O, 5, 3, "abc", 3.14, 'a');
Please see attached tests for more examples.
This patch has been reviewed by Doug and Richard. Minor changes (non-functionality affecting) have been made since both of them formally looked at it, but the changes involve removal of supernumerary return type deduction changes (since they are now redundant, with richard having committed a recent patch to address return type deduction for C++11 lambdas using C++14 semantics).
Some implementation notes:
- Add a new Declarator context => LambdaExprParameterContext to
clang::Declarator to allow the use of 'auto' in declaring generic
lambda parameters
- Add various helpers to CXXRecordDecl to facilitate identifying
and querying a closure class
- LambdaScopeInfo (which maintains the current lambda's Sema state)
was augmented to house the current depth of the template being
parsed (id est the Parser calls Sema::RecordParsingTemplateParameterDepth)
so that SemaType.cpp::ConvertDeclSpecToType may use it to immediately
generate a template-parameter-type when 'auto' is parsed in a generic
lambda parameter context. (i.e we do NOT use AutoType deduced to
a template parameter type - Richard seemed ok with this approach).
We encode that this template type was generated from an auto by simply
adding $auto to the name which can be used for better diagnostics if needed.
- SemaLambda.h was added to hold some common lambda utility
functions (this file is likely to grow ...)
- Teach Sema::ActOnStartOfFunctionDef to check whether it
is being called to instantiate a generic lambda's call
operator, and if so, push an appropriately prepared
LambdaScopeInfo object on the stack.
- various tests were added - but much more will be needed.
There is obviously more work to be done, and both Richard (weakly) and Doug (strongly)
have requested that LambdaExpr be removed form the CXXRecordDecl LambdaDefinitionaData
in a future patch which is forthcoming.
A greatful thanks to all reviewers including Eli Friedman, James Dennett,
and especially the two gracious wizards (Richard Smith and Doug Gregor)
who spent hours providing feedback (in person in Chicago and on the mailing lists).
And yet I am certain that I have allowed unidentified bugs to creep in; bugs, that I will do my best to slay, once identified!
Thanks!
llvm-svn: 191453
When a comma occurs in a default argument or default initializer within a
class, disambiguate whether it is part of the initializer or whether it ends
the initializer.
The way this works (which I will be proposing for standardization) is to treat
the comma as ending the default argument or default initializer if the
following token sequence matches the syntactic constraints of a
parameter-declaration-clause or init-declarator-list (respectively).
This is both consistent with the disambiguation rules elsewhere (where entities
are treated as declarations if they can be), and should have no regressions
over our old behavior. I think it might also disambiguate all cases correctly,
but I don't have a proof of that.
There is an annoyance here: because we're performing a tentative parse in a
situation where we may not have seen declarations of all relevant entities (if
the comma is part of the initializer, lookup may find entites declared later in
the class), we need to turn off typo-correction and diagnostics during the
tentative parse, and in the rare case that we decide the comma is part of the
initializer, we need to revert all token annotations we performed while
disambiguating.
Any diagnostics that occur outside of the immediate context of the tentative
parse (for instance, if we trigger the implicit instantiation of a class
template) are *not* suppressed, mirroring the usual rules for a SFINAE context.
llvm-svn: 190639
is at the end of the line, point to the location after the double colon instead
of at the next token. There is more context to be given this way. In addition,
the next token can be several lines later.
llvm-svn: 190029
Specifically, the following features are not included in this commit:
- any sort of capturing within generic lambdas
- nested lambdas
- conversion operator for captureless lambdas
- ensuring all visitors are generic lambda aware
As an example of what compiles:
template <class F1, class F2>
struct overload : F1, F2 {
using F1::operator();
using F2::operator();
overload(F1 f1, F2 f2) : F1(f1), F2(f2) { }
};
auto Recursive = [](auto Self, auto h, auto ... rest) {
return 1 + Self(Self, rest...);
};
auto Base = [](auto Self, auto h) {
return 1;
};
overload<decltype(Base), decltype(Recursive)> O(Base, Recursive);
int num_params = O(O, 5, 3, "abc", 3.14, 'a');
Please see attached tests for more examples.
Some implementation notes:
- Add a new Declarator context => LambdaExprParameterContext to
clang::Declarator to allow the use of 'auto' in declaring generic
lambda parameters
- Augment AutoType's constructor (similar to how variadic
template-type-parameters ala TemplateTypeParmDecl are implemented) to
accept an IsParameterPack to encode a generic lambda parameter pack.
- Add various helpers to CXXRecordDecl to facilitate identifying
and querying a closure class
- LambdaScopeInfo (which maintains the current lambda's Sema state)
was augmented to house the current depth of the template being
parsed (id est the Parser calls Sema::RecordParsingTemplateParameterDepth)
so that Sema::ActOnLambdaAutoParameter may use it to create the
appropriate list of corresponding TemplateTypeParmDecl for each
auto parameter identified within the generic lambda (also stored
within the current LambdaScopeInfo). Additionally,
a TemplateParameterList data-member was added to hold the invented
TemplateParameterList AST node which will be much more useful
once we teach TreeTransform how to transform generic lambdas.
- SemaLambda.h was added to hold some common lambda utility
functions (this file is likely to grow ...)
- Teach Sema::ActOnStartOfFunctionDef to check whether it
is being called to instantiate a generic lambda's call
operator, and if so, push an appropriately prepared
LambdaScopeInfo object on the stack.
- Teach Sema::ActOnStartOfLambdaDefinition to set the
return type of a lambda without a trailing return type
to 'auto' in C++1y mode, and teach the return type
deduction machinery in SemaStmt.cpp to process either
C++11 and C++14 lambda's correctly depending on the flag.
- various tests were added - but much more will be needed.
A greatful thanks to all reviewers including Eli Friedman,
James Dennett and the ever illuminating Richard Smith. And
yet I am certain that I have allowed unidentified bugs to creep in;
bugs, that I will do my best to slay, once identified!
Thanks!
llvm-svn: 188977
When we are parsing a type for an alias template, we are not entering
the context, so we can't look into dependent classes. Make sure the
parser handles this correctly.
PR16904.
llvm-svn: 188510
followed by an identifier, then diagnose an identifier as being a bogus part of
the declarator instead of tripping over it. Improves diagnostics for cases like
std::vector<const int *p> my_vec;
llvm-svn: 186061
PR16456 reported that Clang implements a hybrid between AltiVec's
"Keyword and Predefine Method" and its "Context Sensitive Keyword
Method," where "bool" is always a keyword, but "vector" and "pixel"
are context-sensitive keywords. This isn't permitted by the AltiVec
spec. For consistency with gcc, this patch implements the Context
Sensitive Keyword Method for bool, and stops treating true and false
as keywords in Altivec mode.
The patch removes KEYALTIVEC as a trigger for defining these keywords
in include/clang/Basic/TokenKinds.def, and adds logic for "vector
bool" that mirrors the existing logic for "vector pixel." The test
case is taken from the bug report.
llvm-svn: 185580
- 'register' storage class
- dynamic exception specifications
Only the former check is enabled by default for now (the latter might be quite noisy).
llvm-svn: 183881
places which weren't setting it up properly. This allows us to get the right
cv-qualifiers for 'this' when it appears outside a method body in a class
template.
llvm-svn: 183483
The most common (non-buggy) case are where such objects are used as
return expressions in bool-returning functions or as boolean function
arguments. In those cases I've used (& added if necessary) a named
function to provide the equivalent (or sometimes negative, depending on
convenient wording) test.
DiagnosticBuilder kept its implicit conversion operator owing to the
prevalent use of it in return statements.
One bug was found in ExprConstant.cpp involving a comparison of two
PointerUnions (PointerUnion did not previously have an operator==, so
instead both operands were converted to bool & then compared). A test
is included in test/SemaCXX/constant-expression-cxx1y.cpp for the fix
(adding operator== to PointerUnion in LLVM).
llvm-svn: 181869
This change partly addresses a heinous problem we have with the
parsing of attribute arguments that are a lone identifier. Previously,
we would end up parsing the 'align' attribute of this as an expression
"(Align)":
template<unsigned Size, unsigned Align>
class my_aligned_storage
{
__attribute__((align((Align)))) char storage[Size];
};
while this would parse as a "parameter name" 'Align':
template<unsigned Size, unsigned Align>
class my_aligned_storage
{
__attribute__((align(Align))) char storage[Size];
};
The code that handles the alignment attribute would completely ignore
the parameter name, so the while the first of these would do what's
expected, the second would silently be equivalent to
template<unsigned Size, unsigned Align>
class my_aligned_storage
{
__attribute__((align)) char storage[Size];
};
i.e., use the maximal alignment rather than the specified alignment.
Address this by sniffing the "Args" provided in the TableGen
description of attributes. If the first argument is "obviously"
something that should be treated as an expression (rather than an
identifier to be matched later), parse it as an expression.
Fixes <rdar://problem/13700933>.
llvm-svn: 180973
This change partly addresses a heinous problem we have with the
parsing of attribute arguments that are a lone identifier. Previously,
we would end up parsing the 'align' attribute of this as an expression
"(Align)":
template<unsigned Size, unsigned Align>
class my_aligned_storage
{
__attribute__((align((Align)))) char storage[Size];
};
while this would parse as a "parameter name" 'Align':
template<unsigned Size, unsigned Align>
class my_aligned_storage
{
__attribute__((align(Align))) char storage[Size];
};
The code that handles the alignment attribute would completely ignore
the parameter name, so the while the first of these would do what's
expected, the second would silently be equivalent to
template<unsigned Size, unsigned Align>
class my_aligned_storage
{
__attribute__((align)) char storage[Size];
};
i.e., use the maximal alignment rather than the specified alignment.
Address this by sniffing the "Args" provided in the TableGen
description of attributes. If the first argument is "obviously"
something that should be treated as an expression (rather than an
identifier to be matched later), parse it as an expression.
Fixes <rdar://problem/13700933>.
llvm-svn: 180970
C++1y, so stop adding the 'const' there. Provide a compatibility warning for
code relying on this in C++11, with a fix-it hint. Update our lazily-written
tests to add the const, except for those ones which were testing our
implementation of this rule.
llvm-svn: 179969
When we are consuming the current token just to enter a new token stream, we push
the current token in the back of the stream so that we get it again.
Unfortunately this had the effect where if the current token is a code-completion one,
we would code-complete once during consuming it and another time after the stream ended.
Fix this by making sure that, in this case, ConsumeAnyToken() will consume a code-completion
token without invoking code-completion.
rdar://12842503
llvm-svn: 178199
Faisal Vali