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/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index 6ebfb57..bde9c15 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -32,6 +32,7 @@
#include "clang/Sema/CXXFieldCollector.h"
#include "clang/Sema/DeclSpec.h"
#include "clang/Sema/Initialization.h"
+#include "clang/Sema/SemaLambda.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/ParsedTemplate.h"
#include "clang/Sema/Scope.h"
@@ -10015,29 +10016,27 @@
SourceLocation CurrentLocation,
CXXConversionDecl *Conv)
{
- CXXRecordDecl *Lambda = Conv->getParent();
+ CXXRecordDecl *LambdaClass = Conv->getParent();
// Make sure that the lambda call operator is marked used.
- markLambdaCallOperatorUsed(*this, Lambda);
+ markLambdaCallOperatorUsed(*this, LambdaClass);
Conv->setUsed();
SynthesizedFunctionScope Scope(*this, Conv);
DiagnosticErrorTrap Trap(Diags);
- // Return the address of the __invoke function.
- DeclarationName InvokeName = &Context.Idents.get("__invoke");
- CXXMethodDecl *Invoke
- = cast<CXXMethodDecl>(Lambda->lookup(InvokeName).front());
+ CXXMethodDecl *Invoke = LambdaClass->getLambdaStaticInvoker();
+
Expr *FunctionRef = BuildDeclRefExpr(Invoke, Invoke->getType(),
VK_LValue, Conv->getLocation()).take();
- assert(FunctionRef && "Can't refer to __invoke function?");
+ assert(FunctionRef && "Can't refer to lambda static invoker function?");
Stmt *Return = ActOnReturnStmt(Conv->getLocation(), FunctionRef).take();
Conv->setBody(new (Context) CompoundStmt(Context, Return,
Conv->getLocation(),
Conv->getLocation()));
- // Fill in the __invoke function with a dummy implementation. IR generation
+ // Fill in the invoke function with a dummy implementation. IR generation
// will fill in the actual details.
Invoke->setUsed();
Invoke->setReferenced();