P0091R3: Implement basic parsing support for C++17 deduction-guides.
We model deduction-guides as functions with a new kind of name that identifies
the template whose deduction they guide; the bulk of this patch is adding the
new name kind. This gives us a clean way to attach an extensible list of guides
to a class template in a way that doesn't require any special handling in AST
files etc (and we're going to need these functions we come to performing
deduction).
llvm-svn: 294266
diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index 6da61c6..9e8823f 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -3025,6 +3025,16 @@
isConstructorDeclarator(/*Unqualified*/true))
goto DoneWithDeclSpec;
+ // Likewise, if this is a context where the identifier could be a template
+ // name, check whether this is a deduction guide declaration.
+ if (getLangOpts().CPlusPlus1z &&
+ (DSContext == DSC_class || DSContext == DSC_top_level) &&
+ Actions.isDeductionGuideName(getCurScope(), *Tok.getIdentifierInfo(),
+ Tok.getLocation()) &&
+ isConstructorDeclarator(/*Unqualified*/ true,
+ /*DeductionGuide*/ true))
+ goto DoneWithDeclSpec;
+
isInvalid = DS.SetTypeSpecType(DeclSpec::TST_typename, Loc, PrevSpec,
DiagID, TypeRep, Policy);
if (isInvalid)
@@ -4644,7 +4654,7 @@
}
}
-bool Parser::isConstructorDeclarator(bool IsUnqualified) {
+bool Parser::isConstructorDeclarator(bool IsUnqualified, bool DeductionGuide) {
TentativeParsingAction TPA(*this);
// Parse the C++ scope specifier.
@@ -4732,6 +4742,11 @@
case tok::r_paren:
// C(X )
+ if (DeductionGuide) {
+ // C(X) -> ... is a deduction guide.
+ IsConstructor = NextToken().is(tok::arrow);
+ break;
+ }
if (NextToken().is(tok::colon) || NextToken().is(tok::kw_try)) {
// Assume these were meant to be constructors:
// C(X) : (the name of a bit-field cannot be parenthesized).
@@ -4749,7 +4764,7 @@
//
// FIXME: We can actually do this whether or not the name is qualified,
// because if it is qualified in this context it must be being used as
- // a constructor name. However, we do not implement that rule correctly
+ // a constructor name.
// currently, so we're somewhat conservative here.
IsConstructor = IsUnqualified;
}
@@ -5280,21 +5295,29 @@
// We found something that indicates the start of an unqualified-id.
// Parse that unqualified-id.
bool AllowConstructorName;
- if (D.getDeclSpec().hasTypeSpecifier())
+ bool AllowDeductionGuide;
+ if (D.getDeclSpec().hasTypeSpecifier()) {
AllowConstructorName = false;
- else if (D.getCXXScopeSpec().isSet())
+ AllowDeductionGuide = false;
+ } else if (D.getCXXScopeSpec().isSet()) {
AllowConstructorName =
(D.getContext() == Declarator::FileContext ||
D.getContext() == Declarator::MemberContext);
- else
+ AllowDeductionGuide = false;
+ } else {
AllowConstructorName = (D.getContext() == Declarator::MemberContext);
+ AllowDeductionGuide =
+ (D.getContext() == Declarator::FileContext ||
+ D.getContext() == Declarator::MemberContext);
+ }
SourceLocation TemplateKWLoc;
bool HadScope = D.getCXXScopeSpec().isValid();
if (ParseUnqualifiedId(D.getCXXScopeSpec(),
/*EnteringContext=*/true,
/*AllowDestructorName=*/true, AllowConstructorName,
- nullptr, TemplateKWLoc, D.getName()) ||
+ AllowDeductionGuide, nullptr, TemplateKWLoc,
+ D.getName()) ||
// Once we're past the identifier, if the scope was bad, mark the
// whole declarator bad.
D.getCXXScopeSpec().isInvalid()) {
diff --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp
index 6403caa..d558909 100644
--- a/clang/lib/Parse/ParseDeclCXX.cpp
+++ b/clang/lib/Parse/ParseDeclCXX.cpp
@@ -576,6 +576,7 @@
/*AllowDestructorName=*/true,
/*AllowConstructorName=*/!(Tok.is(tok::identifier) &&
NextToken().is(tok::equal)),
+ /*AllowDeductionGuide=*/false,
nullptr, D.TemplateKWLoc, D.Name))
return true;
}
@@ -2426,8 +2427,8 @@
// Try to parse an unqualified-id.
SourceLocation TemplateKWLoc;
UnqualifiedId Name;
- if (ParseUnqualifiedId(SS, false, true, true, nullptr, TemplateKWLoc,
- Name)) {
+ if (ParseUnqualifiedId(SS, false, true, true, false, nullptr,
+ TemplateKWLoc, Name)) {
SkipUntil(tok::semi);
return nullptr;
}
diff --git a/clang/lib/Parse/ParseExpr.cpp b/clang/lib/Parse/ParseExpr.cpp
index ee06c76..0c09614 100644
--- a/clang/lib/Parse/ParseExpr.cpp
+++ b/clang/lib/Parse/ParseExpr.cpp
@@ -1693,6 +1693,7 @@
/*AllowDestructorName=*/true,
/*AllowConstructorName=*/
getLangOpts().MicrosoftExt,
+ /*AllowDeductionGuide=*/false,
ObjectType, TemplateKWLoc, Name)) {
(void)Actions.CorrectDelayedTyposInExpr(LHS);
LHS = ExprError();
diff --git a/clang/lib/Parse/ParseExprCXX.cpp b/clang/lib/Parse/ParseExprCXX.cpp
index cfda2cd..1ba1695 100644
--- a/clang/lib/Parse/ParseExprCXX.cpp
+++ b/clang/lib/Parse/ParseExprCXX.cpp
@@ -546,6 +546,7 @@
/*EnteringContext=*/false,
/*AllowDestructorName=*/false,
/*AllowConstructorName=*/false,
+ /*AllowDeductionGuide=*/false,
/*ObjectType=*/nullptr, TemplateKWLoc, Name))
return ExprError();
@@ -2429,6 +2430,8 @@
///
/// \param AllowConstructorName whether we allow parsing a constructor name.
///
+/// \param AllowDeductionGuide whether we allow parsing a deduction guide name.
+///
/// \param ObjectType if this unqualified-id occurs within a member access
/// expression, the type of the base object whose member is being accessed.
///
@@ -2438,6 +2441,7 @@
bool Parser::ParseUnqualifiedId(CXXScopeSpec &SS, bool EnteringContext,
bool AllowDestructorName,
bool AllowConstructorName,
+ bool AllowDeductionGuide,
ParsedType ObjectType,
SourceLocation& TemplateKWLoc,
UnqualifiedId &Result) {
@@ -2466,6 +2470,7 @@
return false;
}
+ ParsedTemplateTy TemplateName;
if (AllowConstructorName &&
Actions.isCurrentClassName(*Id, getCurScope(), &SS)) {
// We have parsed a constructor name.
@@ -2474,6 +2479,12 @@
/*IsCtorOrDtorName=*/true,
/*NonTrivialTypeSourceInfo=*/true);
Result.setConstructorName(Ty, IdLoc, IdLoc);
+ } else if (getLangOpts().CPlusPlus1z &&
+ AllowDeductionGuide && SS.isEmpty() &&
+ Actions.isDeductionGuideName(getCurScope(), *Id, IdLoc,
+ &TemplateName)) {
+ // We have parsed a template-name naming a deduction guide.
+ Result.setDeductionGuideName(TemplateName, IdLoc);
} else {
// We have parsed an identifier.
Result.setIdentifier(Id, IdLoc);
diff --git a/clang/lib/Parse/ParseOpenMP.cpp b/clang/lib/Parse/ParseOpenMP.cpp
index cab7d34..574ed6e 100644
--- a/clang/lib/Parse/ParseOpenMP.cpp
+++ b/clang/lib/Parse/ParseOpenMP.cpp
@@ -1053,7 +1053,7 @@
IsCorrect = false;
SkipUntil(tok::comma, tok::r_paren, tok::annot_pragma_openmp_end,
StopBeforeMatch);
- } else if (ParseUnqualifiedId(SS, false, false, false, nullptr,
+ } else if (ParseUnqualifiedId(SS, false, false, false, false, nullptr,
TemplateKWLoc, Name)) {
IsCorrect = false;
SkipUntil(tok::comma, tok::r_paren, tok::annot_pragma_openmp_end,
@@ -1557,8 +1557,9 @@
}
return P.ParseUnqualifiedId(ReductionIdScopeSpec, /*EnteringContext*/ false,
/*AllowDestructorName*/ false,
- /*AllowConstructorName*/ false, nullptr,
- TemplateKWLoc, ReductionId);
+ /*AllowConstructorName*/ false,
+ /*AllowDeductionGuide*/ false,
+ nullptr, TemplateKWLoc, ReductionId);
}
/// Parses clauses with list.
diff --git a/clang/lib/Parse/ParseStmtAsm.cpp b/clang/lib/Parse/ParseStmtAsm.cpp
index 7fd9fa2..59e96d9 100644
--- a/clang/lib/Parse/ParseStmtAsm.cpp
+++ b/clang/lib/Parse/ParseStmtAsm.cpp
@@ -224,6 +224,7 @@
/*EnteringContext=*/false,
/*AllowDestructorName=*/false,
/*AllowConstructorName=*/false,
+ /*AllowDeductionGuide=*/false,
/*ObjectType=*/nullptr, TemplateKWLoc, Id);
// Perform the lookup.
Result = Actions.LookupInlineAsmIdentifier(SS, TemplateKWLoc, Id, Info,
diff --git a/clang/lib/Parse/Parser.cpp b/clang/lib/Parse/Parser.cpp
index 8713bb2..9030ebf 100644
--- a/clang/lib/Parse/Parser.cpp
+++ b/clang/lib/Parse/Parser.cpp
@@ -1966,8 +1966,10 @@
// Parse the unqualified-id.
SourceLocation TemplateKWLoc; // FIXME: parsed, but unused.
- if (ParseUnqualifiedId(Result.SS, false, true, true, nullptr, TemplateKWLoc,
- Result.Name)) {
+ if (ParseUnqualifiedId(
+ Result.SS, /*EnteringContext*/false, /*AllowDestructorName*/true,
+ /*AllowConstructorName*/true, /*AllowDeductionGuide*/false, nullptr,
+ TemplateKWLoc, Result.Name)) {
T.skipToEnd();
return true;
}