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/AST/DeclCXX.cpp b/lib/AST/DeclCXX.cpp
index ccd8220..b50aa93 100644
--- a/lib/AST/DeclCXX.cpp
+++ b/lib/AST/DeclCXX.cpp
@@ -20,6 +20,7 @@
#include "clang/AST/ExprCXX.h"
#include "clang/AST/TypeLoc.h"
#include "clang/Basic/IdentifierTable.h"
+#include "clang/Sema/SemaLambda.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
using namespace clang;
@@ -930,6 +931,40 @@
return isPOD() && data().HasOnlyCMembers;
}
+bool CXXRecordDecl::isGenericLambda() const {
+ return isLambda() &&
+ getLambdaCallOperator()->getDescribedFunctionTemplate();
+}
+
+CXXMethodDecl* CXXRecordDecl::getLambdaCallOperator() const {
+ if (!isLambda()) return 0;
+ DeclarationName Name =
+ getASTContext().DeclarationNames.getCXXOperatorName(OO_Call);
+ DeclContext::lookup_const_result Calls = lookup(Name);
+
+ assert(!Calls.empty() && "Missing lambda call operator!");
+ assert(Calls.size() == 1 && "More than one lambda call operator!");
+
+ NamedDecl *CallOp = Calls.front();
+ if (FunctionTemplateDecl *CallOpTmpl =
+ dyn_cast<FunctionTemplateDecl>(CallOp))
+ return cast<CXXMethodDecl>(CallOpTmpl->getTemplatedDecl());
+
+ return cast<CXXMethodDecl>(CallOp);
+}
+
+CXXMethodDecl* CXXRecordDecl::getLambdaStaticInvoker() const {
+ if (!isLambda()) return 0;
+ DeclarationName Name =
+ &getASTContext().Idents.get(getLambdaStaticInvokerName());
+ DeclContext::lookup_const_result Invoker = lookup(Name);
+ if (Invoker.empty()) return 0;
+ assert(Invoker.size() == 1 && "More than one static invoker operator!");
+ CXXMethodDecl *Result = cast<CXXMethodDecl>(Invoker.front());
+ return Result;
+
+}
+
void CXXRecordDecl::getCaptureFields(
llvm::DenseMap<const VarDecl *, FieldDecl *> &Captures,
FieldDecl *&ThisCapture) const {
@@ -947,6 +982,14 @@
}
}
+TemplateParameterList*
+ CXXRecordDecl::getGenericLambdaTemplateParameterList() const {
+ if (!isLambda()) return 0;
+ CXXMethodDecl *CallOp = getLambdaCallOperator();
+ if (FunctionTemplateDecl *Tmpl = CallOp->getDescribedFunctionTemplate())
+ return Tmpl->getTemplateParameters();
+ return 0;
+}
static CanQualType GetConversionType(ASTContext &Context, NamedDecl *Conv) {
QualType T;
@@ -1493,7 +1536,7 @@
bool CXXMethodDecl::isLambdaStaticInvoker() const {
return getParent()->isLambda() &&
- getIdentifier() && getIdentifier()->getName() == "__invoke";
+ getParent()->getLambdaStaticInvoker() == this;
}