Implement a rudimentary form of generic lambdas.
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!
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@188977 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Parse/ParseDecl.cpp b/lib/Parse/ParseDecl.cpp
index 392535a..4c4ce87 100644
--- a/lib/Parse/ParseDecl.cpp
+++ b/lib/Parse/ParseDecl.cpp
@@ -4670,6 +4670,7 @@
// as part of the parameter-declaration-clause.
if (Tok.is(tok::ellipsis) && D.getCXXScopeSpec().isEmpty() &&
!((D.getContext() == Declarator::PrototypeContext ||
+ D.getContext() == Declarator::LambdaExprParameterContext ||
D.getContext() == Declarator::BlockLiteralContext) &&
NextToken().is(tok::r_paren) &&
!D.hasGroupingParens() &&
@@ -4988,7 +4989,6 @@
TypeResult TrailingReturnType;
Actions.ActOnStartFunctionDeclarator();
-
/* LocalEndLoc is the end location for the local FunctionTypeLoc.
EndLoc is the end location for the function declarator.
They differ for trailing return types. */
@@ -5009,7 +5009,8 @@
EndLoc = RParenLoc;
} else {
if (Tok.isNot(tok::r_paren))
- ParseParameterDeclarationClause(D, FirstArgAttrs, ParamInfo, EllipsisLoc);
+ ParseParameterDeclarationClause(D, FirstArgAttrs, ParamInfo,
+ EllipsisLoc);
else if (RequiresArg)
Diag(Tok, diag::err_argument_required_after_attribute);
@@ -5240,7 +5241,6 @@
ParsedAttributes &FirstArgAttrs,
SmallVectorImpl<DeclaratorChunk::ParamInfo> &ParamInfo,
SourceLocation &EllipsisLoc) {
-
while (1) {
if (Tok.is(tok::ellipsis)) {
// FIXME: Issue a diagnostic if we parsed an attribute-specifier-seq
@@ -5270,16 +5270,21 @@
ParseDeclarationSpecifiers(DS);
- // Parse the declarator. This is "PrototypeContext", because we must
- // accept either 'declarator' or 'abstract-declarator' here.
- Declarator ParmDecl(DS, Declarator::PrototypeContext);
- ParseDeclarator(ParmDecl);
+
+ // Parse the declarator. This is "PrototypeContext" or
+ // "LambdaExprParameterContext", because we must accept either
+ // 'declarator' or 'abstract-declarator' here.
+ Declarator ParmDeclarator(DS,
+ D.getContext() == Declarator::LambdaExprContext ?
+ Declarator::LambdaExprParameterContext :
+ Declarator::PrototypeContext);
+ ParseDeclarator(ParmDeclarator);
// Parse GNU attributes, if present.
- MaybeParseGNUAttributes(ParmDecl);
+ MaybeParseGNUAttributes(ParmDeclarator);
// Remember this parsed parameter in ParamInfo.
- IdentifierInfo *ParmII = ParmDecl.getIdentifier();
+ IdentifierInfo *ParmII = ParmDeclarator.getIdentifier();
// DefArgToks is used when the parsing of default arguments needs
// to be delayed.
@@ -5287,8 +5292,8 @@
// If no parameter was specified, verify that *something* was specified,
// otherwise we have a missing type and identifier.
- if (DS.isEmpty() && ParmDecl.getIdentifier() == 0 &&
- ParmDecl.getNumTypeObjects() == 0) {
+ if (DS.isEmpty() && ParmDeclarator.getIdentifier() == 0 &&
+ ParmDeclarator.getNumTypeObjects() == 0) {
// Completely missing, emit error.
Diag(DSStart, diag::err_missing_param);
} else {
@@ -5297,8 +5302,8 @@
// Inform the actions module about the parameter declarator, so it gets
// added to the current scope.
- Decl *Param = Actions.ActOnParamDeclarator(getCurScope(), ParmDecl);
-
+ Decl *Param = Actions.ActOnParamDeclarator(getCurScope(),
+ ParmDeclarator);
// Parse the default argument, if any. We parse the default
// arguments in all dialects; the semantic analysis in
// ActOnParamDefaultArgument will reject the default argument in
@@ -5359,8 +5364,8 @@
}
ParamInfo.push_back(DeclaratorChunk::ParamInfo(ParmII,
- ParmDecl.getIdentifierLoc(), Param,
- DefArgToks));
+ ParmDeclarator.getIdentifierLoc(),
+ Param, DefArgToks));
}
// If the next token is a comma, consume it and keep reading arguments.