Revert desugaring of CompoundAssignment into arithmetic operation and assignment

4 files changed, 146 insertions, 12 deletions

diff --git a/gcc/rust/hir/rust-ast-lower-expr.h b/gcc/rust/hir/rust-ast-lower-expr.h
index 54cb6113..f36096b 100644
--- a/gcc/rust/hir/rust-ast-lower-expr.h
+++ b/gcc/rust/hir/rust-ast-lower-expr.h
@@ -452,11 +452,8 @@ public:
 			       expr.get_locus ());
   }
 
-  /* Compound assignment expression is compiled away. */
   void visit (AST::CompoundAssignmentExpr &expr) override
   {
-    /* First we need to find the corresponding arithmetic or logical operator.
-     */
     ArithmeticOrLogicalOperator op;
     switch (expr.get_expr_type ())
       {
@@ -503,15 +500,10 @@ public:
     Analysis::NodeMapping mapping (crate_num, expr.get_node_id (),
 				   mappings->get_next_hir_id (crate_num),
 				   UNKNOWN_LOCAL_DEFID);
-    HIR::Expr *operator_expr
-      = new HIR::ArithmeticOrLogicalExpr (mapping, asignee_expr->clone_expr (),
-					  std::unique_ptr<HIR::Expr> (value),
-					  op, expr.get_locus ());
-    translated
-      = new HIR::AssignmentExpr (mapping,
-				 std::unique_ptr<HIR::Expr> (asignee_expr),
-				 std::unique_ptr<HIR::Expr> (operator_expr),
-				 expr.get_locus ());
+
+    translated = new HIR::CompoundAssignmentExpr (
+      mapping, std::unique_ptr<HIR::Expr> (asignee_expr),
+      std::unique_ptr<HIR::Expr> (value), op, expr.get_locus ());
   }
 
   void visit (AST::StructExprStruct &struct_expr) override
diff --git a/gcc/rust/hir/tree/rust-hir-expr.h b/gcc/rust/hir/tree/rust-hir-expr.h
index 37ec15d..901feda 100644
--- a/gcc/rust/hir/tree/rust-hir-expr.h
+++ b/gcc/rust/hir/tree/rust-hir-expr.h
@@ -666,6 +666,80 @@ protected:
   }
 };
 
+class CompoundAssignmentExpr : public OperatorExpr
+{
+public:
+  using ExprType = ArithmeticOrLogicalOperator;
+
+private:
+  // Note: overloading trait specified in comments
+  ExprType expr_type;
+  std::unique_ptr<Expr> right_expr;
+
+public:
+  std::string as_string () const override;
+
+  ExprType get_expr_type () const { return expr_type; }
+
+  // Use pointers in constructor to enable polymorphism
+  CompoundAssignmentExpr (Analysis::NodeMapping mappings,
+			  std::unique_ptr<Expr> value_to_assign_to,
+			  std::unique_ptr<Expr> value_to_assign,
+			  ExprType expr_kind, Location locus)
+    : OperatorExpr (std::move (mappings), std::move (value_to_assign_to),
+		    AST::AttrVec (), locus),
+      expr_type (expr_kind), right_expr (std::move (value_to_assign))
+  {}
+  // outer attributes not allowed
+
+  // Have clone in copy constructor
+  CompoundAssignmentExpr (CompoundAssignmentExpr const &other)
+    : OperatorExpr (other), expr_type (other.expr_type),
+      right_expr (other.right_expr->clone_expr ())
+  {}
+
+  // Overload assignment operator to clone
+  CompoundAssignmentExpr &operator= (CompoundAssignmentExpr const &other)
+  {
+    OperatorExpr::operator= (other);
+    // main_or_left_expr = other.main_or_left_expr->clone_expr();
+    right_expr = other.right_expr->clone_expr ();
+    expr_type = other.expr_type;
+    // outer_attrs = other.outer_attrs;
+
+    return *this;
+  }
+
+  // move constructors
+  CompoundAssignmentExpr (CompoundAssignmentExpr &&other) = default;
+  CompoundAssignmentExpr &operator= (CompoundAssignmentExpr &&other) = default;
+
+  void accept_vis (HIRVisitor &vis) override;
+
+  std::unique_ptr<Expr> &get_left_expr ()
+  {
+    rust_assert (main_or_left_expr != nullptr);
+    return main_or_left_expr;
+  }
+
+  std::unique_ptr<Expr> &get_right_expr ()
+  {
+    rust_assert (right_expr != nullptr);
+    return right_expr;
+  }
+
+  void visit_lhs (HIRVisitor &vis) { main_or_left_expr->accept_vis (vis); }
+  void visit_rhs (HIRVisitor &vis) { right_expr->accept_vis (vis); }
+
+protected:
+  /* Use covariance to implement clone function as returning this object rather
+   * than base */
+  CompoundAssignmentExpr *clone_expr_without_block_impl () const override
+  {
+    return new CompoundAssignmentExpr (*this);
+  }
+};
+
 // Expression in parentheses (i.e. like literally just any 3 + (2 * 6))
 class GroupedExpr : public ExprWithoutBlock
 {
diff --git a/gcc/rust/hir/tree/rust-hir-full-test.cc b/gcc/rust/hir/tree/rust-hir-full-test.cc
index bacef82..843e32c 100644
--- a/gcc/rust/hir/tree/rust-hir-full-test.cc
+++ b/gcc/rust/hir/tree/rust-hir-full-test.cc
@@ -1316,6 +1316,67 @@ AssignmentExpr::as_string () const
 }
 
 std::string
+CompoundAssignmentExpr::as_string () const
+{
+  std::string operator_str;
+  operator_str.reserve (1);
+
+  // get operator string
+  switch (expr_type)
+    {
+    case ArithmeticOrLogicalOperator::ADD:
+      operator_str = "+";
+      break;
+    case ArithmeticOrLogicalOperator::SUBTRACT:
+      operator_str = "-";
+      break;
+    case ArithmeticOrLogicalOperator::MULTIPLY:
+      operator_str = "*";
+      break;
+    case ArithmeticOrLogicalOperator::DIVIDE:
+      operator_str = "/";
+      break;
+    case ArithmeticOrLogicalOperator::MODULUS:
+      operator_str = "%";
+      break;
+    case ArithmeticOrLogicalOperator::BITWISE_AND:
+      operator_str = "&";
+      break;
+    case ArithmeticOrLogicalOperator::BITWISE_OR:
+      operator_str = "|";
+      break;
+    case ArithmeticOrLogicalOperator::BITWISE_XOR:
+      operator_str = "^";
+      break;
+    case ArithmeticOrLogicalOperator::LEFT_SHIFT:
+      operator_str = "<<";
+      break;
+    case ArithmeticOrLogicalOperator::RIGHT_SHIFT:
+      operator_str = ">>";
+      break;
+    default:
+      gcc_unreachable ();
+      break;
+    }
+
+  operator_str += "=";
+
+  std::string str ("CompoundAssignmentExpr: ");
+  if (main_or_left_expr == nullptr || right_expr == nullptr)
+    {
+      str += "error. this is probably a parsing failure.";
+    }
+  else
+    {
+      str += "\n left: " + main_or_left_expr->as_string ();
+      str += "\n right: " + right_expr->as_string ();
+      str += "\n operator: " + operator_str;
+    }
+
+  return str;
+}
+
+std::string
 AsyncBlockExpr::as_string () const
 {
   std::string str = "AsyncBlockExpr: ";
@@ -3819,6 +3880,12 @@ AssignmentExpr::accept_vis (HIRVisitor &vis)
 }
 
 void
+CompoundAssignmentExpr::accept_vis (HIRVisitor &vis)
+{
+  vis.visit (*this);
+}
+
+void
 GroupedExpr::accept_vis (HIRVisitor &vis)
 {
   vis.visit (*this);
diff --git a/gcc/rust/hir/tree/rust-hir-visitor.h b/gcc/rust/hir/tree/rust-hir-visitor.h
index 0487446..ea125d9 100644
--- a/gcc/rust/hir/tree/rust-hir-visitor.h
+++ b/gcc/rust/hir/tree/rust-hir-visitor.h
@@ -47,6 +47,7 @@ public:
   virtual void visit (LazyBooleanExpr &expr) = 0;
   virtual void visit (TypeCastExpr &expr) = 0;
   virtual void visit (AssignmentExpr &expr) = 0;
+  virtual void visit (CompoundAssignmentExpr &expr) = 0;
   virtual void visit (GroupedExpr &expr) = 0;
   virtual void visit (ArrayElemsValues &elems) = 0;
   virtual void visit (ArrayElemsCopied &elems) = 0;