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.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@143867 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 83 insertions, 54 deletions

diff --git a/lib/CodeGen/CodeGenFunction.h b/lib/CodeGen/CodeGenFunction.h
index 4940e21c8b..0b31ce43a9 100644
--- a/lib/CodeGen/CodeGenFunction.h
+++ b/lib/CodeGen/CodeGenFunction.h
@@ -950,20 +950,86 @@ public:
 
   public:
     PeepholeProtection() : Inst(0) {}
-  };  
+  };
 
-  /// An RAII object to set (and then clear) a mapping for an OpaqueValueExpr.
-  class OpaqueValueMapping {
-    CodeGenFunction &CGF;
+  /// A non-RAII class containing all the information about a bound
+  /// opaque value.  OpaqueValueMapping, below, is a RAII wrapper for
+  /// this which makes individual mappings very simple; using this
+  /// class directly is useful when you have a variable number of
+  /// opaque values or don't want the RAII functionality for some
+  /// reason.
+  class OpaqueValueMappingData {
     const OpaqueValueExpr *OpaqueValue;
     bool BoundLValue;
     CodeGenFunction::PeepholeProtection Protection;
 
+    OpaqueValueMappingData(const OpaqueValueExpr *ov,
+                           bool boundLValue)
+      : OpaqueValue(ov), BoundLValue(boundLValue) {}
   public:
+    OpaqueValueMappingData() : OpaqueValue(0) {}
+
     static bool shouldBindAsLValue(const Expr *expr) {
       return expr->isGLValue() || expr->getType()->isRecordType();
     }
 
+    static OpaqueValueMappingData bind(CodeGenFunction &CGF,
+                                       const OpaqueValueExpr *ov,
+                                       const Expr *e) {
+      if (shouldBindAsLValue(ov))
+        return bind(CGF, ov, CGF.EmitLValue(e));
+      return bind(CGF, ov, CGF.EmitAnyExpr(e));
+    }
+
+    static OpaqueValueMappingData bind(CodeGenFunction &CGF,
+                                       const OpaqueValueExpr *ov,
+                                       const LValue &lv) {
+      assert(shouldBindAsLValue(ov));
+      CGF.OpaqueLValues.insert(std::make_pair(ov, lv));
+      return OpaqueValueMappingData(ov, true);
+    }
+
+    static OpaqueValueMappingData bind(CodeGenFunction &CGF,
+                                       const OpaqueValueExpr *ov,
+                                       const RValue &rv) {
+      assert(!shouldBindAsLValue(ov));
+      CGF.OpaqueRValues.insert(std::make_pair(ov, rv));
+
+      OpaqueValueMappingData data(ov, false);
+
+      // Work around an extremely aggressive peephole optimization in
+      // EmitScalarConversion which assumes that all other uses of a
+      // value are extant.
+      data.Protection = CGF.protectFromPeepholes(rv);
+
+      return data;
+    }
+
+    bool isValid() const { return OpaqueValue != 0; }
+    void clear() { OpaqueValue = 0; }
+
+    void unbind(CodeGenFunction &CGF) {
+      assert(OpaqueValue && "no data to unbind!");
+
+      if (BoundLValue) {
+        CGF.OpaqueLValues.erase(OpaqueValue);
+      } else {
+        CGF.OpaqueRValues.erase(OpaqueValue);
+        CGF.unprotectFromPeepholes(Protection);
+      }
+    }
+  };
+
+  /// An RAII object to set (and then clear) a mapping for an OpaqueValueExpr.
+  class OpaqueValueMapping {
+    CodeGenFunction &CGF;
+    OpaqueValueMappingData Data;
+
+  public:
+    static bool shouldBindAsLValue(const Expr *expr) {
+      return OpaqueValueMappingData::shouldBindAsLValue(expr);
+    }
+
     /// Build the opaque value mapping for the given conditional
     /// operator if it's the GNU ?: extension.  This is a common
     /// enough pattern that the convenience operator is really
@@ -971,75 +1037,34 @@ public:
     ///
     OpaqueValueMapping(CodeGenFunction &CGF,
                        const AbstractConditionalOperator *op) : CGF(CGF) {
-      if (isa<ConditionalOperator>(op)) {
-        OpaqueValue = 0;
-        BoundLValue = false;
+      if (isa<ConditionalOperator>(op))
+        // Leave Data empty.
         return;
-      }
 
       const BinaryConditionalOperator *e = cast<BinaryConditionalOperator>(op);
-      init(e->getOpaqueValue(), e->getCommon());
+      Data = OpaqueValueMappingData::bind(CGF, e->getOpaqueValue(),
+                                          e->getCommon());
     }
 
     OpaqueValueMapping(CodeGenFunction &CGF,
                        const OpaqueValueExpr *opaqueValue,
                        LValue lvalue)
-      : CGF(CGF), OpaqueValue(opaqueValue), BoundLValue(true) {
-      assert(opaqueValue && "no opaque value expression!");
-      assert(shouldBindAsLValue(opaqueValue));
-      initLValue(lvalue);
+      : CGF(CGF), Data(OpaqueValueMappingData::bind(CGF, opaqueValue, lvalue)) {
     }
 
     OpaqueValueMapping(CodeGenFunction &CGF,
                        const OpaqueValueExpr *opaqueValue,
                        RValue rvalue)
-      : CGF(CGF), OpaqueValue(opaqueValue), BoundLValue(false) {
-      assert(opaqueValue && "no opaque value expression!");
-      assert(!shouldBindAsLValue(opaqueValue));
-      initRValue(rvalue);
+      : CGF(CGF), Data(OpaqueValueMappingData::bind(CGF, opaqueValue, rvalue)) {
     }
 
     void pop() {
-      assert(OpaqueValue && "mapping already popped!");
-      popImpl();
-      OpaqueValue = 0;
+      Data.unbind(CGF);
+      Data.clear();
     }
 
     ~OpaqueValueMapping() {
-      if (OpaqueValue) popImpl();
-    }
-
-  private:
-    void popImpl() {
-      if (BoundLValue)
-        CGF.OpaqueLValues.erase(OpaqueValue);
-      else {
-        CGF.OpaqueRValues.erase(OpaqueValue);
-        CGF.unprotectFromPeepholes(Protection);
-      }
-    }
-
-    void init(const OpaqueValueExpr *ov, const Expr *e) {
-      OpaqueValue = ov;
-      BoundLValue = shouldBindAsLValue(ov);
-      assert(BoundLValue == shouldBindAsLValue(e)
-             && "inconsistent expression value kinds!");
-      if (BoundLValue)
-        initLValue(CGF.EmitLValue(e));
-      else
-        initRValue(CGF.EmitAnyExpr(e));
-    }
-
-    void initLValue(const LValue &lv) {
-      CGF.OpaqueLValues.insert(std::make_pair(OpaqueValue, lv));
-    }
-
-    void initRValue(const RValue &rv) {
-      // Work around an extremely aggressive peephole optimization in
-      // EmitScalarConversion which assumes that all other uses of a
-      // value are extant.
-      Protection = CGF.protectFromPeepholes(rv);
-      CGF.OpaqueRValues.insert(std::make_pair(OpaqueValue, rv));
+      if (Data.isValid()) Data.unbind(CGF);
     }
   };
   
@@ -2015,6 +2040,10 @@ public:
   LValue EmitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *E);
   LValue EmitOpaqueValueLValue(const OpaqueValueExpr *e);
 
+  RValue EmitPseudoObjectRValue(const PseudoObjectExpr *e,
+                                AggValueSlot slot = AggValueSlot::ignored());
+  LValue EmitPseudoObjectLValue(const PseudoObjectExpr *e);
+
   llvm::Value *EmitIvarOffset(const ObjCInterfaceDecl *Interface,
                               const ObjCIvarDecl *Ivar);
   LValue EmitLValueForAnonRecordField(llvm::Value* Base,