Remove vtables from the Stmt hierarchy; this was pretty easy as

there were only three virtual methods of any significance.

The primary way to grab child iterators now is with
  Stmt::child_range children();
  Stmt::const_child_range children() const;
where a child_range is just a std::pair of iterators suitable for
being llvm::tie'd to some locals.  I've left the old child_begin()
and child_end() accessors in place, but it's probably a substantial
penalty to grab the iterators individually now, since the
switch-based dispatch is kindof inherently slower than vtable
dispatch.  Grabbing them together is probably a slight win over the
status quo, although of course we could've achieved that with vtables, too.

I also reclassified SwitchCase (correctly) as an abstract Stmt
class, which (as the first such class that wasn't an Expr subclass)
required some fiddling in a few places.

There are somewhat gross metaprogramming hooks in place to ensure
that new statements/expressions continue to implement
getSourceRange() and children().  I had to work around a recent clang
bug;  dgregor actually fixed it already, but I didn't want to
introduce a selfhosting dependency on ToT.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@125183 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 49 insertions, 238 deletions

diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index 747f786542..6280d633aa 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -30,8 +30,6 @@
 #include <algorithm>
 using namespace clang;
 
-void Expr::ANCHOR() {} // key function for Expr class.
-
 /// isKnownToHaveBooleanValue - Return true if this is an integer expression
 /// that is known to return 0 or 1.  This happens for _Bool/bool expressions
 /// but also int expressions which are produced by things like comparisons in
@@ -93,6 +91,42 @@ bool Expr::isKnownToHaveBooleanValue() const {
   return false;
 }
 
+// Amusing macro metaprogramming hack: check whether a class provides
+// a more specific implementation of getExprLoc().
+namespace {
+  /// This implementation is used when a class provides a custom
+  /// implementation of getExprLoc.
+  template <class E, class T>
+  SourceLocation getExprLocImpl(const Expr *expr,
+                                SourceLocation (T::*v)() const) {
+    return static_cast<const E*>(expr)->getExprLoc();
+  }
+
+  /// This implementation is used when a class doesn't provide
+  /// a custom implementation of getExprLoc.  Overload resolution
+  /// should pick it over the implementation above because it's
+  /// more specialized according to function template partial ordering.
+  template <class E>
+  SourceLocation getExprLocImpl(const Expr *expr,
+                                SourceLocation (Expr::*v)() const) {
+    return static_cast<const E*>(expr)->getSourceRange().getBegin();
+  }
+}
+
+SourceLocation Expr::getExprLoc() const {
+  switch (getStmtClass()) {
+  case Stmt::NoStmtClass: llvm_unreachable("statement without class");
+#define ABSTRACT_STMT(type)
+#define STMT(type, base) \
+  case Stmt::type##Class: llvm_unreachable(#type " is not an Expr"); break;
+#define EXPR(type, base) \
+  case Stmt::type##Class: return getExprLocImpl<type>(this, &type::getExprLoc);
+#include "clang/AST/StmtNodes.inc"
+  }
+  llvm_unreachable("unknown statement kind");
+  return SourceLocation();
+}
+
 //===----------------------------------------------------------------------===//
 // Primary Expressions.
 //===----------------------------------------------------------------------===//
@@ -1560,7 +1594,8 @@ static Expr::CanThrowResult MergeCanThrow(Expr::CanThrowResult CT1,
 static Expr::CanThrowResult CanSubExprsThrow(ASTContext &C, const Expr *CE) {
   Expr *E = const_cast<Expr*>(CE);
   Expr::CanThrowResult R = Expr::CT_Cannot;
-  for (Expr::child_iterator I = E->child_begin(), IE = E->child_end();
+  Expr::child_iterator I, IE;
+  for (llvm::tie(I, IE) = E->children();
        I != IE && R != Expr::CT_Can; ++I) {
     R = MergeCanThrow(R, cast<Expr>(*I)->CanThrow(C));
   }
@@ -2735,242 +2770,29 @@ const Expr* ConstExprIterator::operator->() const { return cast<Expr>(*I); }
 //  Child Iterators for iterating over subexpressions/substatements
 //===----------------------------------------------------------------------===//
 
-// DeclRefExpr
-Stmt::child_iterator DeclRefExpr::child_begin() { return child_iterator(); }
-Stmt::child_iterator DeclRefExpr::child_end() { return child_iterator(); }
-
-// ObjCIvarRefExpr
-Stmt::child_iterator ObjCIvarRefExpr::child_begin() { return &Base; }
-Stmt::child_iterator ObjCIvarRefExpr::child_end() { return &Base+1; }
-
-// ObjCPropertyRefExpr
-Stmt::child_iterator ObjCPropertyRefExpr::child_begin()
-{ 
-  if (Receiver.is<Stmt*>()) {
-    // Hack alert!
-    return reinterpret_cast<Stmt**> (&Receiver);
-  }
-  return child_iterator(); 
-}
-
-Stmt::child_iterator ObjCPropertyRefExpr::child_end()
-{ return Receiver.is<Stmt*>() ? 
-          reinterpret_cast<Stmt**> (&Receiver)+1 : 
-          child_iterator(); 
-}
-
-// ObjCIsaExpr
-Stmt::child_iterator ObjCIsaExpr::child_begin() { return &Base; }
-Stmt::child_iterator ObjCIsaExpr::child_end() { return &Base+1; }
-
-// PredefinedExpr
-Stmt::child_iterator PredefinedExpr::child_begin() { return child_iterator(); }
-Stmt::child_iterator PredefinedExpr::child_end() { return child_iterator(); }
-
-// IntegerLiteral
-Stmt::child_iterator IntegerLiteral::child_begin() { return child_iterator(); }
-Stmt::child_iterator IntegerLiteral::child_end() { return child_iterator(); }
-
-// CharacterLiteral
-Stmt::child_iterator CharacterLiteral::child_begin() { return child_iterator();}
-Stmt::child_iterator CharacterLiteral::child_end() { return child_iterator(); }
-
-// FloatingLiteral
-Stmt::child_iterator FloatingLiteral::child_begin() { return child_iterator(); }
-Stmt::child_iterator FloatingLiteral::child_end() { return child_iterator(); }
-
-// ImaginaryLiteral
-Stmt::child_iterator ImaginaryLiteral::child_begin() { return &Val; }
-Stmt::child_iterator ImaginaryLiteral::child_end() { return &Val+1; }
-
-// StringLiteral
-Stmt::child_iterator StringLiteral::child_begin() { return child_iterator(); }
-Stmt::child_iterator StringLiteral::child_end() { return child_iterator(); }
-
-// ParenExpr
-Stmt::child_iterator ParenExpr::child_begin() { return &Val; }
-Stmt::child_iterator ParenExpr::child_end() { return &Val+1; }
-
-// UnaryOperator
-Stmt::child_iterator UnaryOperator::child_begin() { return &Val; }
-Stmt::child_iterator UnaryOperator::child_end() { return &Val+1; }
-
-// OffsetOfExpr
-Stmt::child_iterator OffsetOfExpr::child_begin() {
-  return reinterpret_cast<Stmt **> (reinterpret_cast<OffsetOfNode *> (this + 1)
-                                      + NumComps);
-}
-Stmt::child_iterator OffsetOfExpr::child_end() {
-  return child_iterator(&*child_begin() + NumExprs);
-}
-
 // SizeOfAlignOfExpr
-Stmt::child_iterator SizeOfAlignOfExpr::child_begin() {
+Stmt::child_range SizeOfAlignOfExpr::children() {
   // If this is of a type and the type is a VLA type (and not a typedef), the
   // size expression of the VLA needs to be treated as an executable expression.
   // Why isn't this weirdness documented better in StmtIterator?
   if (isArgumentType()) {
     if (const VariableArrayType* T = dyn_cast<VariableArrayType>(
                                    getArgumentType().getTypePtr()))
-      return child_iterator(T);
-    return child_iterator();
+      return child_range(child_iterator(T), child_iterator());
+    return child_range();
   }
-  return child_iterator(&Argument.Ex);
-}
-Stmt::child_iterator SizeOfAlignOfExpr::child_end() {
-  if (isArgumentType())
-    return child_iterator();
-  return child_iterator(&Argument.Ex + 1);
-}
-
-// ArraySubscriptExpr
-Stmt::child_iterator ArraySubscriptExpr::child_begin() {
-  return &SubExprs[0];
-}
-Stmt::child_iterator ArraySubscriptExpr::child_end() {
-  return &SubExprs[0]+END_EXPR;
-}
-
-// CallExpr
-Stmt::child_iterator CallExpr::child_begin() {
-  return &SubExprs[0];
-}
-Stmt::child_iterator CallExpr::child_end() {
-  return &SubExprs[0]+NumArgs+getNumPreArgs()+PREARGS_START;
-}
-
-// MemberExpr
-Stmt::child_iterator MemberExpr::child_begin() { return &Base; }
-Stmt::child_iterator MemberExpr::child_end() { return &Base+1; }
-
-// ExtVectorElementExpr
-Stmt::child_iterator ExtVectorElementExpr::child_begin() { return &Base; }
-Stmt::child_iterator ExtVectorElementExpr::child_end() { return &Base+1; }
-
-// CompoundLiteralExpr
-Stmt::child_iterator CompoundLiteralExpr::child_begin() { return &Init; }
-Stmt::child_iterator CompoundLiteralExpr::child_end() { return &Init+1; }
-
-// CastExpr
-Stmt::child_iterator CastExpr::child_begin() { return &Op; }
-Stmt::child_iterator CastExpr::child_end() { return &Op+1; }
-
-// BinaryOperator
-Stmt::child_iterator BinaryOperator::child_begin() {
-  return &SubExprs[0];
-}
-Stmt::child_iterator BinaryOperator::child_end() {
-  return &SubExprs[0]+END_EXPR;
-}
-
-// ConditionalOperator
-Stmt::child_iterator ConditionalOperator::child_begin() {
-  return &SubExprs[0];
-}
-Stmt::child_iterator ConditionalOperator::child_end() {
-  return &SubExprs[0]+END_EXPR;
-}
-
-// AddrLabelExpr
-Stmt::child_iterator AddrLabelExpr::child_begin() { return child_iterator(); }
-Stmt::child_iterator AddrLabelExpr::child_end() { return child_iterator(); }
-
-// StmtExpr
-Stmt::child_iterator StmtExpr::child_begin() { return &SubStmt; }
-Stmt::child_iterator StmtExpr::child_end() { return &SubStmt+1; }
-
-
-// ChooseExpr
-Stmt::child_iterator ChooseExpr::child_begin() { return &SubExprs[0]; }
-Stmt::child_iterator ChooseExpr::child_end() { return &SubExprs[0]+END_EXPR; }
-
-// GNUNullExpr
-Stmt::child_iterator GNUNullExpr::child_begin() { return child_iterator(); }
-Stmt::child_iterator GNUNullExpr::child_end() { return child_iterator(); }
-
-// ShuffleVectorExpr
-Stmt::child_iterator ShuffleVectorExpr::child_begin() {
-  return &SubExprs[0];
-}
-Stmt::child_iterator ShuffleVectorExpr::child_end() {
-  return &SubExprs[0]+NumExprs;
-}
-
-// VAArgExpr
-Stmt::child_iterator VAArgExpr::child_begin() { return &Val; }
-Stmt::child_iterator VAArgExpr::child_end() { return &Val+1; }
-
-// InitListExpr
-Stmt::child_iterator InitListExpr::child_begin() {
-  return InitExprs.size() ? &InitExprs[0] : 0;
-}
-Stmt::child_iterator InitListExpr::child_end() {
-  return InitExprs.size() ? &InitExprs[0] + InitExprs.size() : 0;
-}
-
-// DesignatedInitExpr
-Stmt::child_iterator DesignatedInitExpr::child_begin() {
-  char* Ptr = static_cast<char*>(static_cast<void *>(this));
-  Ptr += sizeof(DesignatedInitExpr);
-  return reinterpret_cast<Stmt**>(reinterpret_cast<void**>(Ptr));
-}
-Stmt::child_iterator DesignatedInitExpr::child_end() {
-  return child_iterator(&*child_begin() + NumSubExprs);
-}
-
-// ImplicitValueInitExpr
-Stmt::child_iterator ImplicitValueInitExpr::child_begin() {
-  return child_iterator();
-}
-
-Stmt::child_iterator ImplicitValueInitExpr::child_end() {
-  return child_iterator();
-}
-
-// ParenListExpr
-Stmt::child_iterator ParenListExpr::child_begin() {
-  return &Exprs[0];
-}
-Stmt::child_iterator ParenListExpr::child_end() {
-  return &Exprs[0]+NumExprs;
-}
-
-// ObjCStringLiteral
-Stmt::child_iterator ObjCStringLiteral::child_begin() {
-  return &String;
-}
-Stmt::child_iterator ObjCStringLiteral::child_end() {
-  return &String+1;
-}
-
-// ObjCEncodeExpr
-Stmt::child_iterator ObjCEncodeExpr::child_begin() { return child_iterator(); }
-Stmt::child_iterator ObjCEncodeExpr::child_end() { return child_iterator(); }
-
-// ObjCSelectorExpr
-Stmt::child_iterator ObjCSelectorExpr::child_begin() {
-  return child_iterator();
-}
-Stmt::child_iterator ObjCSelectorExpr::child_end() {
-  return child_iterator();
-}
-
-// ObjCProtocolExpr
-Stmt::child_iterator ObjCProtocolExpr::child_begin() {
-  return child_iterator();
-}
-Stmt::child_iterator ObjCProtocolExpr::child_end() {
-  return child_iterator();
+  return child_range(&Argument.Ex, &Argument.Ex + 1);
 }
 
 // ObjCMessageExpr
-Stmt::child_iterator ObjCMessageExpr::child_begin() {
+Stmt::child_range ObjCMessageExpr::children() {
+  Stmt **begin;
   if (getReceiverKind() == Instance)
-    return reinterpret_cast<Stmt **>(this + 1);
-  return reinterpret_cast<Stmt **>(getArgs());
-}
-Stmt::child_iterator ObjCMessageExpr::child_end() {
-  return reinterpret_cast<Stmt **>(getArgs() + getNumArgs());
+    begin = reinterpret_cast<Stmt **>(this + 1);
+  else
+    begin = reinterpret_cast<Stmt **>(getArgs());
+  return child_range(begin,
+                     reinterpret_cast<Stmt **>(getArgs() + getNumArgs()));
 }
 
 // Blocks
@@ -2988,14 +2810,3 @@ BlockDeclRefExpr::BlockDeclRefExpr(VarDecl *d, QualType t, ExprValueKind VK,
   ExprBits.ValueDependent = ValueDependent;
 }
 
-Stmt::child_iterator BlockExpr::child_begin() { return child_iterator(); }
-Stmt::child_iterator BlockExpr::child_end() { return child_iterator(); }
-
-Stmt::child_iterator BlockDeclRefExpr::child_begin() { return child_iterator();}
-Stmt::child_iterator BlockDeclRefExpr::child_end() { return child_iterator(); }
-
-// OpaqueValueExpr
-SourceRange OpaqueValueExpr::getSourceRange() const { return Loc; }
-Stmt::child_iterator OpaqueValueExpr::child_begin() { return child_iterator(); }
-Stmt::child_iterator OpaqueValueExpr::child_end() { return child_iterator(); }
-