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/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index 462c2d3..5b1a608 100644
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -4740,7 +4740,9 @@
QualType Deduced = readType(*Loc.F, Record, Idx);
bool IsDecltypeAuto = Record[Idx++];
bool IsDependent = Deduced.isNull() ? Record[Idx++] : false;
- return Context.getAutoType(Deduced, IsDecltypeAuto, IsDependent);
+ bool IsParameterPack = Record[Idx++];
+ return Context.getAutoType(Deduced, IsDecltypeAuto, IsDependent,
+ IsParameterPack);
}
case TYPE_RECORD: {
diff --git a/lib/Serialization/ASTReaderDecl.cpp b/lib/Serialization/ASTReaderDecl.cpp
index 7099d32..74e9937 100644
--- a/lib/Serialization/ASTReaderDecl.cpp
+++ b/lib/Serialization/ASTReaderDecl.cpp
@@ -1201,6 +1201,7 @@
= (Capture*)Reader.Context.Allocate(sizeof(Capture)*Lambda.NumCaptures);
Capture *ToCapture = Lambda.Captures;
Lambda.MethodTyInfo = GetTypeSourceInfo(Record, Idx);
+ Lambda.TheLambdaExpr = cast<LambdaExpr>(Reader.ReadExpr(F));
for (unsigned I = 0, N = Lambda.NumCaptures; I != N; ++I) {
SourceLocation Loc = ReadSourceLocation(Record, Idx);
bool IsImplicit = Record[Idx++];
diff --git a/lib/Serialization/ASTWriter.cpp b/lib/Serialization/ASTWriter.cpp
index d848530..01bc9cb 100644
--- a/lib/Serialization/ASTWriter.cpp
+++ b/lib/Serialization/ASTWriter.cpp
@@ -253,6 +253,7 @@
Record.push_back(T->isDecltypeAuto());
if (T->getDeducedType().isNull())
Record.push_back(T->isDependentType());
+ Record.push_back(T->containsUnexpandedParameterPack());
Code = TYPE_AUTO;
}
@@ -5136,6 +5137,7 @@
Record.push_back(Lambda.ManglingNumber);
AddDeclRef(Lambda.ContextDecl, Record);
AddTypeSourceInfo(Lambda.MethodTyInfo, Record);
+ AddStmt(Lambda.TheLambdaExpr);
for (unsigned I = 0, N = Lambda.NumCaptures; I != N; ++I) {
LambdaExpr::Capture &Capture = Lambda.Captures[I];
AddSourceLocation(Capture.getLocation(), Record);