Introduce basic ASTs for lambda expressions. This covers:
- Capturing variables by-reference and by-copy within a lambda
- The representation of lambda captures
- The creation of the non-static data members in the lambda class
that store the captured variables
- The initialization of the non-static data members from the
captured variables
- Pretty-printing lambda expressions
There are a number of FIXMEs, both explicit and implied, including:
- Creating a field for a capture of 'this'
- Improved diagnostics for initialization failures when capturing
variables by copy
- Dealing with temporaries created during said initialization
- Template instantiation
- AST (de-)serialization
- Binding and returning the lambda expression; turning it into a
proper temporary
- Lots and lots of semantic constraints
- Parameter pack captures
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@149977 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index c219797..f656f90 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -9637,11 +9637,77 @@
byRef = hasBlocksAttr || type->isReferenceType();
}
- // Build a copy expression if we are capturing by copy and the copy
- // might be non-trivial.
+ // Build a copy expression if we are capturing by copy into a
+ // block and the copy might be non-trivial.
Expr *copyExpr = 0;
const RecordType *rtype;
- if (!byRef && getLangOptions().CPlusPlus &&
+ if (isLambda) {
+ CXXRecordDecl *Lambda = cast<LambdaScopeInfo>(CSI)->Lambda;
+ QualType FieldType;
+ if (byRef) {
+ // C++11 [expr.prim.lambda]p15:
+ // An entity is captured by reference if it is implicitly or
+ // explicitly captured but not captured by copy. It is
+ // unspecified whether additional unnamed non-static data
+ // members are declared in the closure type for entities
+ // captured by reference.
+ FieldType = Context.getLValueReferenceType(type.getNonReferenceType());
+ } else {
+ // C++11 [expr.prim.lambda]p14:
+ //
+ // For each entity captured by copy, an unnamed non-static
+ // data member is declared in the closure type. The
+ // declaration order of these members is unspecified. The type
+ // of such a data member is the type of the corresponding
+ // captured entity if the entity is not a reference to an
+ // object, or the referenced type otherwise. [Note: If the
+ // captured entity is a reference to a function, the
+ // corresponding data member is also a reference to a
+ // function. - end note ]
+ if (const ReferenceType *RefType
+ = type->getAs<ReferenceType>()) {
+ if (!RefType->getPointeeType()->isFunctionType())
+ FieldType = RefType->getPointeeType();
+ else
+ FieldType = type;
+ } else {
+ FieldType = type;
+ }
+ }
+
+ // Build the non-static data member.
+ FieldDecl *Field
+ = FieldDecl::Create(Context, Lambda, loc, loc, 0, FieldType,
+ Context.getTrivialTypeSourceInfo(FieldType, loc),
+ 0, false, false);
+ Field->setImplicit(true);
+ Field->setAccess(AS_private);
+
+ // C++11 [expr.prim.lambda]p21:
+ // When the lambda-expression is evaluated, the entities that
+ // are captured by copy are used to direct-initialize each
+ // corresponding non-static data member of the resulting closure
+ // object. (For array members, the array elements are
+ // direct-initialized in increasing subscript order.) These
+ // initializations are performed in the (unspecified) order in
+ // which the non-static data members are declared.
+ //
+ // FIXME: Introduce an initialization entity for lambda captures.
+ // FIXME: Totally broken for arrays.
+ Expr *Ref = new (Context) DeclRefExpr(var, type.getNonReferenceType(),
+ VK_LValue, loc);
+ InitializedEntity InitEntity
+ = InitializedEntity::InitializeMember(Field, /*Parent=*/0);
+ InitializationKind InitKind
+ = InitializationKind::CreateDirect(loc, loc, loc);
+ InitializationSequence Init(*this, InitEntity, InitKind, &Ref, 1);
+ if (!Init.Diagnose(*this, InitEntity, InitKind, &Ref, 1)) {
+ ExprResult Result = Init.Perform(*this, InitEntity, InitKind,
+ MultiExprArg(*this, &Ref, 1));
+ if (!Result.isInvalid())
+ copyExpr = Result.take();
+ }
+ } else if (!byRef && getLangOptions().CPlusPlus &&
(rtype = type.getNonReferenceType()->getAs<RecordType>())) {
// The capture logic needs the destructor, so make sure we mark it.
// Usually this is unnecessary because most local variables have
@@ -9654,10 +9720,10 @@
// According to the blocks spec, the capture of a variable from
// the stack requires a const copy constructor. This is not true
// of the copy/move done to move a __block variable to the heap.
- // There is no equivalent language in the C++11 specification of lambdas.
- if (isBlock)
- type.addConst();
+ type.addConst();
+ // FIXME: Add an initialized entity for lambda capture.
+ // FIXME: Won't work for arrays, although we do need this behavior.
Expr *declRef = new (Context) DeclRefExpr(var, type, VK_LValue, loc);
ExprResult result =
PerformCopyInitialization(
diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index 30b0529..cd2c210 100644
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -4895,6 +4895,7 @@
// at this point, but we need something to attach child declarations to.
QualType MethodTy;
TypeSourceInfo *MethodTyInfo;
+ bool ExplicitParams = true;
if (ParamInfo.getNumTypeObjects() == 0) {
// C++11 [expr.prim.lambda]p4:
// If a lambda-expression does not include a lambda-declarator, it is as
@@ -4904,6 +4905,7 @@
MethodTy = Context.getFunctionType(Context.DependentTy,
/*Args=*/0, /*NumArgs=*/0, EPI);
MethodTyInfo = Context.getTrivialTypeSourceInfo(MethodTy);
+ ExplicitParams = false;
} else {
assert(ParamInfo.isFunctionDeclarator() &&
"lambda-declarator is a function");
@@ -4967,9 +4969,10 @@
LSI->ImpCaptureStyle = LambdaScopeInfo::ImpCap_LambdaByval;
else if (Intro.Default == LCD_ByRef)
LSI->ImpCaptureStyle = LambdaScopeInfo::ImpCap_LambdaByref;
-
+ LSI->IntroducerRange = Intro.Range;
+ LSI->ExplicitParams = ExplicitParams;
LSI->Mutable = (Method->getTypeQualifiers() & Qualifiers::Const) == 0;
-
+
// Handle explicit captures.
for (llvm::SmallVector<LambdaCapture, 4>::const_iterator
C = Intro.Captures.begin(),
@@ -5116,8 +5119,78 @@
ExprResult Sema::ActOnLambdaExpr(SourceLocation StartLoc,
Stmt *Body, Scope *CurScope) {
- // FIXME: Implement
+ // Leave the expression-evaluation context.
+ DiscardCleanupsInEvaluationContext();
+ PopExpressionEvaluationContext();
+
+ // Leave the context of the lambda.
+ PopDeclContext();
+
+ // FIXME: End-of-lambda checking
+
+ // Collect information from the lambda scope.
+ llvm::SmallVector<LambdaExpr::Capture, 4> Captures;
+ llvm::SmallVector<Expr *, 4> CaptureInits;
+ LambdaCaptureDefault CaptureDefault;
+ CXXRecordDecl *Class;
+ SourceRange IntroducerRange;
+ bool ExplicitParams;
+ {
+ LambdaScopeInfo *LSI = getCurLambda();
+ Class = LSI->Lambda;
+ IntroducerRange = LSI->IntroducerRange;
+ ExplicitParams = LSI->ExplicitParams;
+
+ // Translate captures.
+ for (unsigned I = 0, N = LSI->Captures.size(); I != N; ++I) {
+ LambdaScopeInfo::Capture From = LSI->Captures[I];
+ assert(!From.isBlockCapture() && "Cannot capture __block variables");
+ bool IsImplicit = I >= LSI->NumExplicitCaptures;
+
+ // Handle 'this' capture.
+ if (From.isThisCapture()) {
+ Captures.push_back(LambdaExpr::Capture(From.getLocation(),
+ IsImplicit,
+ LCK_This));
+ CaptureInits.push_back(new (Context) CXXThisExpr(From.getLocation(),
+ getCurrentThisType(),
+ /*isImplicit=*/true));
+ continue;
+ }
+
+ VarDecl *Var = From.getVariable();
+ // FIXME: Handle pack expansions.
+ LambdaCaptureKind Kind = From.isCopyCapture()? LCK_ByCopy : LCK_ByRef;
+ Captures.push_back(LambdaExpr::Capture(From.getLocation(), IsImplicit,
+ Kind, Var));
+ CaptureInits.push_back(From.getCopyExpr());
+ }
+
+ switch (LSI->ImpCaptureStyle) {
+ case CapturingScopeInfo::ImpCap_None:
+ CaptureDefault = LCD_None;
+ break;
+
+ case CapturingScopeInfo::ImpCap_LambdaByval:
+ CaptureDefault = LCD_ByCopy;
+ break;
+
+ case CapturingScopeInfo::ImpCap_LambdaByref:
+ CaptureDefault = LCD_ByRef;
+ break;
+
+ case CapturingScopeInfo::ImpCap_Block:
+ llvm_unreachable("block capture in lambda");
+ break;
+ }
+
+ PopFunctionScopeInfo();
+ }
+
+ Expr *Lambda = LambdaExpr::Create(Context, Class, IntroducerRange,
+ CaptureDefault, Captures, ExplicitParams,
+ CaptureInits, Body->getLocEnd());
+ (void)Lambda;
Diag(StartLoc, diag::err_lambda_unsupported);
- ActOnLambdaError(StartLoc, CurScope);
return ExprError();
}
diff --git a/lib/Sema/TreeTransform.h b/lib/Sema/TreeTransform.h
index f011b1b..ca72bc7 100644
--- a/lib/Sema/TreeTransform.h
+++ b/lib/Sema/TreeTransform.h
@@ -7620,6 +7620,13 @@
template<typename Derived>
ExprResult
+TreeTransform<Derived>::TransformLambdaExpr(LambdaExpr *E) {
+ assert(false && "Lambda expressions cannot be instantiated (yet)");
+ return ExprError();
+}
+
+template<typename Derived>
+ExprResult
TreeTransform<Derived>::TransformCXXUnresolvedConstructExpr(
CXXUnresolvedConstructExpr *E) {
TypeSourceInfo *T = getDerived().TransformType(E->getTypeSourceInfo());