Add support for attribute 'noescape'.
The attribute informs the compiler that the annotated pointer parameter
of a function cannot escape and enables IRGen to attach attribute
'nocapture' to parameters that are annotated with the attribute. That is
the only optimization that currently takes advantage of 'noescape', but
there are other optimizations that will be added later that improves
IRGen for ObjC blocks.
rdar://problem/19886775
Differential Revision: https://reviews.llvm.org/D32210
llvm-svn: 313722
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index b8432eb..cffb860 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -1531,6 +1531,22 @@
Attr.getAttributeSpellingListIndex()));
}
+static void handleNoEscapeAttr(Sema &S, Decl *D, const AttributeList &Attr) {
+ if (D->isInvalidDecl())
+ return;
+
+ // noescape only applies to pointer types.
+ QualType T = cast<ParmVarDecl>(D)->getType();
+ if (!S.isValidPointerAttrType(T, /* RefOkay */ true)) {
+ S.Diag(Attr.getLoc(), diag::warn_attribute_pointers_only)
+ << Attr.getName() << Attr.getRange() << 0;
+ return;
+ }
+
+ D->addAttr(::new (S.Context) NoEscapeAttr(
+ Attr.getRange(), S.Context, Attr.getAttributeSpellingListIndex()));
+}
+
static void handleAssumeAlignedAttr(Sema &S, Decl *D,
const AttributeList &Attr) {
Expr *E = Attr.getArgAsExpr(0),
@@ -6167,6 +6183,9 @@
case AttributeList::AT_ReturnsNonNull:
handleReturnsNonNullAttr(S, D, Attr);
break;
+ case AttributeList::AT_NoEscape:
+ handleNoEscapeAttr(S, D, Attr);
+ break;
case AttributeList::AT_AssumeAligned:
handleAssumeAlignedAttr(S, D, Attr);
break;