1 files changed, 71 insertions, 14 deletions

diff --git a/gcc/rust/ast/rust-stmt.h b/gcc/rust/ast/rust-stmt.h
index ce7a37a..127ea21 100644
--- a/gcc/rust/ast/rust-stmt.h
+++ b/gcc/rust/ast/rust-stmt.h
@@ -12,6 +12,9 @@ class EmptyStmt : public Stmt
 {
   Location locus;
 
+  // TODO: find another way to store this to save memory?
+  bool marked_for_strip = false;
+
 public:
   std::string as_string () const override { return std::string (1, ';'); }
 
@@ -21,6 +24,10 @@ public:
 
   void accept_vis (ASTVisitor &vis) override;
 
+  // Can't think of any invalid invariants, so store boolean.
+  void mark_for_strip () override { marked_for_strip = true; }
+  bool is_marked_for_strip () const override { return marked_for_strip; }
+
 protected:
   /* Use covariance to implement clone function as returning this object rather
    * than base */
@@ -68,21 +75,41 @@ public:
 
   // Copy constructor with clone
   LetStmt (LetStmt const &other)
-    : outer_attrs (other.outer_attrs),
-      variables_pattern (other.variables_pattern->clone_pattern ()),
-      type (other.type->clone_type ()),
-      init_expr (other.init_expr->clone_expr ()), locus (other.locus)
-  {}
+    : outer_attrs (other.outer_attrs), locus (other.locus)
+  {
+    // guard to prevent null dereference (only required if error state)
+    if (other.variables_pattern != nullptr)
+      variables_pattern = other.variables_pattern->clone_pattern ();
+    
+    // guard to prevent null dereference (always required)
+    if (other.init_expr != nullptr)
+      init_expr = other.init_expr->clone_expr ();
+    if (other.type != nullptr)
+      type = other.type->clone_type ();
+  }
 
   // Overloaded assignment operator to clone
   LetStmt &operator= (LetStmt const &other)
   {
-    variables_pattern = other.variables_pattern->clone_pattern ();
-    init_expr = other.init_expr->clone_expr ();
-    type = other.type->clone_type ();
     outer_attrs = other.outer_attrs;
     locus = other.locus;
 
+    // guard to prevent null dereference (only required if error state)
+    if (other.variables_pattern != nullptr)
+      variables_pattern = other.variables_pattern->clone_pattern ();
+    else
+      variables_pattern = nullptr;
+    
+    // guard to prevent null dereference (always required)
+    if (other.init_expr != nullptr)
+      init_expr = other.init_expr->clone_expr ();
+    else
+      init_expr = nullptr;
+    if (other.type != nullptr)
+      type = other.type->clone_type ();
+    else
+      type = nullptr;
+
     return *this;
   }
 
@@ -94,6 +121,10 @@ public:
 
   void accept_vis (ASTVisitor &vis) override;
 
+  // Invalid if pattern is null, so base stripping on that.
+  void mark_for_strip () override { variables_pattern = nullptr; }
+  bool is_marked_for_strip () const override { return variables_pattern == nullptr; }
+
 protected:
   /* Use covariance to implement clone function as returning this object rather
    * than base */
@@ -138,8 +169,12 @@ public:
 
   // Copy constructor with clone
   ExprStmtWithoutBlock (ExprStmtWithoutBlock const &other)
-    : ExprStmt (other), expr (other.expr->clone_expr_without_block ())
-  {}
+    : ExprStmt (other)
+  {
+    // guard to prevent null dereference (only required if error state)
+    if (other.expr != nullptr)
+      expr = other.expr->clone_expr_without_block ();
+  }
   /*ExprStmtWithoutBlock (ExprStmtWithoutBlock const &other)
     : ExprStmt (other), expr (other.expr->clone_expr ())
   {}*/
@@ -148,9 +183,14 @@ public:
   ExprStmtWithoutBlock &operator= (ExprStmtWithoutBlock const &other)
   {
     ExprStmt::operator= (other);
-    expr = other.expr->clone_expr_without_block ();
     //expr = other.expr->clone_expr ();
 
+    // guard to prevent null dereference (only required if error state)
+    if (other.expr != nullptr)
+      expr = other.expr->clone_expr_without_block ();
+    else
+      expr = nullptr;
+
     return *this;
   }
 
@@ -160,6 +200,10 @@ public:
 
   void accept_vis (ASTVisitor &vis) override;
 
+  // Invalid if expr is null, so base stripping on that.
+  void mark_for_strip () override { expr = nullptr; }
+  bool is_marked_for_strip () const override { return expr == nullptr; }
+
 protected:
   /* Use covariance to implement clone function as returning this object rather
    * than base */
@@ -185,14 +229,23 @@ public:
 
   // Copy constructor with clone
   ExprStmtWithBlock (ExprStmtWithBlock const &other)
-    : ExprStmt (other), expr (other.expr->clone_expr_with_block ())
-  {}
+    : ExprStmt (other)
+  {
+    // guard to prevent null dereference (only required if error state)
+    if (other.expr != nullptr)
+      expr = other.expr->clone_expr_with_block ();
+  }
 
   // Overloaded assignment operator to clone
   ExprStmtWithBlock &operator= (ExprStmtWithBlock const &other)
   {
     ExprStmt::operator= (other);
-    expr = other.expr->clone_expr_with_block ();
+    
+    // guard to prevent null dereference (only required if error state)
+    if (other.expr != nullptr)
+      expr = other.expr->clone_expr_with_block ();
+    else
+      expr = nullptr;
 
     return *this;
   }
@@ -203,6 +256,10 @@ public:
 
   void accept_vis (ASTVisitor &vis) override;
 
+  // Invalid if expr is null, so base stripping on that.
+  void mark_for_strip () override { expr = nullptr; }
+  bool is_marked_for_strip () const override { return expr == nullptr; }
+
 protected:
   /* Use covariance to implement clone function as returning this object rather
    * than base */