[ms-cxxabi] Implement member pointer conversions
Summary:
This only supports converting along non-virtual inheritance paths by
changing the field offset or the non-virtual base adjustment.
This implements three kinds of conversions:
- codegen for Value conversions
- Constant emission for APValue
- Constant folding for CastExprs
In almost all constant initialization settings
EmitMemberPointer(APValue) is called, except when the expression
contains a reinterpret cast.
reinterpret casts end up being a big corner case because the null value
changes between different kinds of member pointers.
Reviewers: rsmith
CC: cfe-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D741
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@181543 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGCXXABI.h b/lib/CodeGen/CGCXXABI.h
index 1e4da63..7f72e1d 100644
--- a/lib/CodeGen/CGCXXABI.h
+++ b/lib/CodeGen/CGCXXABI.h
@@ -192,6 +192,12 @@
/// is required.
llvm::Constant *getMemberPointerAdjustment(const CastExpr *E);
+ /// \brief Computes the non-virtual adjustment needed for a member pointer
+ /// conversion along an inheritance path stored in an APValue. Unlike
+ /// getMemberPointerAdjustment(), the adjustment can be negative if the path
+ /// is from a derived type to a base type.
+ CharUnits getMemberPointerPathAdjustment(const APValue &MP);
+
public:
/// Adjust the given non-null pointer to an object of polymorphic
/// type to point to the complete object.