Change the AST representation of operations on Objective-C

property references to use a new PseudoObjectExpr
expression which pairs a syntactic form of the expression
with a set of semantic expressions implementing it.
This should significantly reduce the complexity required
elsewhere in the compiler to deal with these kinds of
expressions (e.g. IR generation's special l-value kind,
the static analyzer's Message abstraction), at the lower
cost of specifically dealing with the odd AST structure
of these expressions.  It should also greatly simplify
efforts to implement similar language features in the
future, most notably Managed C++'s properties and indexed
properties.

Most of the effort here is in dealing with the various
clients of the AST.  I've gone ahead and simplified the
ObjC rewriter's use of properties;  other clients, like
IR-gen and the static analyzer, have all the old
complexity *and* all the new complexity, at least
temporarily.  Many thanks to Ted for writing and advising
on the necessary changes to the static analyzer.

I've xfailed a small diagnostics regression in the static
analyzer at Ted's request.

llvm-svn: 143867

1 files changed, 10 insertions, 6 deletions

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index febd394eb33..c6a5f1ec6f5 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -7468,7 +7468,7 @@ static QualType CheckAddressOfOperand(Sema &S, ExprResult &OrigOp,
     // The operand must be either an l-value or a function designator
     if (!op->getType()->isFunctionType()) {
       // Use a special diagnostic for loads from property references.
-      if (isa<ObjCPropertyRefExpr>(op->IgnoreImplicit()->IgnoreParens())) {
+      if (isa<PseudoObjectExpr>(op)) {
         AddressOfError = AO_Property_Expansion;
       } else {
         // FIXME: emit more specific diag...
@@ -7483,9 +7483,6 @@ static QualType CheckAddressOfOperand(Sema &S, ExprResult &OrigOp,
   } else if (op->getObjectKind() == OK_VectorComponent) {
     // The operand cannot be an element of a vector
     AddressOfError = AO_Vector_Element;
-  } else if (op->getObjectKind() == OK_ObjCProperty) {
-    // cannot take address of a property expression.
-    AddressOfError = AO_Property_Expansion;
   } else if (dcl) { // C99 6.5.3.2p1
     // We have an lvalue with a decl. Make sure the decl is not declared
     // with the register storage-class specifier.
@@ -8951,8 +8948,15 @@ static void MakeObjCStringLiteralFixItHint(Sema& SemaRef, QualType DstType,
       return;
   }
 
-  // Strip off any parens and casts.
-  StringLiteral *SL = dyn_cast<StringLiteral>(SrcExpr->IgnoreParenCasts());
+  // Ignore any parens, implicit casts (should only be
+  // array-to-pointer decays), and not-so-opaque values.  The last is
+  // important for making this trigger for property assignments.
+  SrcExpr = SrcExpr->IgnoreParenImpCasts();
+  if (OpaqueValueExpr *OV = dyn_cast<OpaqueValueExpr>(SrcExpr))
+    if (OV->getSourceExpr())
+      SrcExpr = OV->getSourceExpr()->IgnoreParenImpCasts();
+
+  StringLiteral *SL = dyn_cast<StringLiteral>(SrcExpr);
   if (!SL || !SL->isAscii())
     return;