Implement support for lambda capture pack expansions, e.g.,
[&values...] { print(values...); }
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@150497 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 4dc8a7b..371a4e3 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -9831,7 +9831,7 @@
// Check if the variable needs to be captured; if so, try to perform
// the capture.
void Sema::TryCaptureVar(VarDecl *var, SourceLocation loc,
- TryCaptureKind Kind) {
+ TryCaptureKind Kind, SourceLocation EllipsisLoc) {
QualType type;
unsigned functionScopesIndex;
bool Nested;
@@ -9909,7 +9909,8 @@
}
}
- CSI->AddCapture(var, hasBlocksAttr, byRef, Nested, loc, copyExpr);
+ CSI->AddCapture(var, hasBlocksAttr, byRef, Nested, loc, EllipsisLoc,
+ copyExpr);
Nested = true;
if (shouldAddConstForScope(CSI, var))
diff --git a/lib/Sema/SemaLambda.cpp b/lib/Sema/SemaLambda.cpp
index 0ce1c74..c75c3c5 100644
--- a/lib/Sema/SemaLambda.cpp
+++ b/lib/Sema/SemaLambda.cpp
@@ -291,9 +291,26 @@
continue;
}
+ // C++11 [expr.prim.lambda]p23:
+ // A capture followed by an ellipsis is a pack expansion (14.5.3).
+ SourceLocation EllipsisLoc;
+ if (C->EllipsisLoc.isValid()) {
+ if (Var->isParameterPack()) {
+ EllipsisLoc = C->EllipsisLoc;
+ } else {
+ Diag(C->EllipsisLoc, diag::err_pack_expansion_without_parameter_packs)
+ << SourceRange(C->Loc);
+
+ // Just ignore the ellipsis.
+ }
+ } else if (Var->isParameterPack()) {
+ Diag(C->Loc, diag::err_lambda_unexpanded_pack);
+ continue;
+ }
+
TryCaptureKind Kind = C->Kind == LCK_ByRef ? TryCapture_ExplicitByRef :
TryCapture_ExplicitByVal;
- TryCaptureVar(Var, C->Loc, Kind);
+ TryCaptureVar(Var, C->Loc, Kind, EllipsisLoc);
}
finishLambdaExplicitCaptures(LSI);
@@ -380,10 +397,9 @@
}
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));
+ Kind, Var, From.getEllipsisLoc()));
CaptureInits.push_back(From.getCopyExpr());
}
diff --git a/lib/Sema/TreeTransform.h b/lib/Sema/TreeTransform.h
index a63b9c8..71037b6 100644
--- a/lib/Sema/TreeTransform.h
+++ b/lib/Sema/TreeTransform.h
@@ -7706,6 +7706,49 @@
continue;
}
+ // Determine the capture kind for Sema.
+ Sema::TryCaptureKind Kind
+ = C->isImplicit()? Sema::TryCapture_Implicit
+ : C->getCaptureKind() == LCK_ByCopy
+ ? Sema::TryCapture_ExplicitByVal
+ : Sema::TryCapture_ExplicitByRef;
+ SourceLocation EllipsisLoc;
+ if (C->isPackExpansion()) {
+ UnexpandedParameterPack Unexpanded(C->getCapturedVar(), C->getLocation());
+ bool ShouldExpand = false;
+ bool RetainExpansion = false;
+ llvm::Optional<unsigned> NumExpansions;
+ if (getDerived().TryExpandParameterPacks(C->getEllipsisLoc(),
+ C->getLocation(),
+ Unexpanded,
+ ShouldExpand, RetainExpansion,
+ NumExpansions))
+ return ExprError();
+
+ if (ShouldExpand) {
+ // The transform has determined that we should perform an expansion;
+ // transform and capture each of the arguments.
+ // expansion of the pattern. Do so.
+ VarDecl *Pack = C->getCapturedVar();
+ for (unsigned I = 0; I != *NumExpansions; ++I) {
+ Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(getSema(), I);
+ VarDecl *CapturedVar
+ = cast_or_null<VarDecl>(getDerived().TransformDecl(C->getLocation(),
+ Pack));
+ if (!CapturedVar) {
+ Invalid = true;
+ continue;
+ }
+
+ // Capture the transformed variable.
+ getSema().TryCaptureVar(CapturedVar, C->getLocation(), Kind);
+ }
+ continue;
+ }
+
+ EllipsisLoc = C->getEllipsisLoc();
+ }
+
// Transform the captured variable.
VarDecl *CapturedVar
= cast_or_null<VarDecl>(getDerived().TransformDecl(C->getLocation(),
@@ -7714,13 +7757,9 @@
Invalid = true;
continue;
}
-
+
// Capture the transformed variable.
- getSema().TryCaptureVar(CapturedVar, C->getLocation(),
- C->isImplicit()? Sema::TryCapture_Implicit
- : C->getCaptureKind() == LCK_ByCopy
- ? Sema::TryCapture_ExplicitByVal
- : Sema::TryCapture_ExplicitByRef);
+ getSema().TryCaptureVar(CapturedVar, C->getLocation(), Kind);
}
if (!FinishedExplicitCaptures)
getSema().finishLambdaExplicitCaptures(LSI);