P0840R2: support for [[no_unique_address]] attribute
Summary:
Add support for the C++2a [[no_unique_address]] attribute for targets using the Itanium C++ ABI.
This depends on D63371.
Reviewers: rjmccall, aaron.ballman
Subscribers: dschuff, aheejin, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D63451
llvm-svn: 363976
diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index a2a4bca..17bb9e9 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -3879,12 +3879,27 @@
return EmitLValueForField(LambdaLV, Field);
}
+/// Get the address of a zero-sized field within a record. The resulting
+/// address doesn't necessarily have the right type.
+static Address emitAddrOfZeroSizeField(CodeGenFunction &CGF, Address Base,
+ const FieldDecl *Field) {
+ CharUnits Offset = CGF.getContext().toCharUnitsFromBits(
+ CGF.getContext().getFieldOffset(Field));
+ if (Offset.isZero())
+ return Base;
+ Base = CGF.Builder.CreateElementBitCast(Base, CGF.Int8Ty);
+ return CGF.Builder.CreateConstInBoundsByteGEP(Base, Offset);
+}
+
/// Drill down to the storage of a field without walking into
/// reference types.
///
/// The resulting address doesn't necessarily have the right type.
static Address emitAddrOfFieldStorage(CodeGenFunction &CGF, Address base,
const FieldDecl *field) {
+ if (field->isZeroSize(CGF.getContext()))
+ return emitAddrOfZeroSizeField(CGF, base, field);
+
const RecordDecl *rec = field->getParent();
unsigned idx =