gcc/rust/ast/rust-stmt.h

   1 // Copyright (C) 2020-2024 Free Software Foundation, Inc.
   2
   3 // This file is part of GCC.
   4
   5 // GCC is free software; you can redistribute it and/or modify it under
   6 // the terms of the GNU General Public License as published by the Free
   7 // Software Foundation; either version 3, or (at your option) any later
   8 // version.
   9
  10 // GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  11 // WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12 // FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13 // for more details.
  14
  15 // You should have received a copy of the GNU General Public License
  16 // along with GCC; see the file COPYING3.  If not see
  17 // <http://www.gnu.org/licenses/>.
  18
  19 #ifndef RUST_AST_STATEMENT_H
  20 #define RUST_AST_STATEMENT_H
  21
  22 #include "rust-ast.h"
  23 #include "rust-path.h"
  24 #include "rust-expr.h"
  25 #include <memory>
  26
  27 namespace Rust {
  28 namespace AST {
  29 // Just a semi-colon, which apparently is a statement.
  30 class EmptyStmt : public Stmt
  31 {
  32   location_t locus;
  33
  34   // TODO: find another way to store this to save memory?
  35   bool marked_for_strip = false;
  36
  37 public:
  38   std::string as_string () const override { return std::string (1, ';'); }
  39
  40   EmptyStmt (location_t locus) : locus (locus) {}
  41
  42   location_t get_locus () const override final { return locus; }
  43
  44   void accept_vis (ASTVisitor &vis) override;
  45
  46   // Can't think of any invalid invariants, so store boolean.
  47   void mark_for_strip () override { marked_for_strip = true; }
  48   bool is_marked_for_strip () const override { return marked_for_strip; }
  49
  50   bool is_item () const override final { return false; }
  51
  52   Stmt::Kind get_stmt_kind () final { return Stmt::Kind::Empty; }
  53
  54 protected:
  55   /* Use covariance to implement clone function as returning this object rather
  56    * than base */
  57   EmptyStmt *clone_stmt_impl () const override { return new EmptyStmt (*this); }
  58 };
  59
  60 /* Variable assignment let statement - type of "declaration statement" as it
  61  * introduces new name into scope */
  62 class LetStmt : public Stmt
  63 {
  64   // bool has_outer_attrs;
  65   std::vector<Attribute> outer_attrs;
  66
  67   std::unique_ptr<Pattern> variables_pattern;
  68
  69   // bool has_type;
  70   std::unique_ptr<Type> type;
  71
  72   // bool has_init_expr;
  73   std::unique_ptr<Expr> init_expr;
  74
  75   location_t locus;
  76
  77 public:
  78   Type *inferedType;
  79
  80   // Returns whether let statement has outer attributes.
  81   bool has_outer_attrs () const { return !outer_attrs.empty (); }
  82
  83   // Returns whether let statement has a given return type.
  84   bool has_type () const { return type != nullptr; }
  85
  86   // Returns whether let statement has an initialisation expression.
  87   bool has_init_expr () const { return init_expr != nullptr; }
  88
  89   std::string as_string () const override;
  90
  91   LetStmt (std::unique_ptr<Pattern> variables_pattern,
  92            std::unique_ptr<Expr> init_expr, std::unique_ptr<Type> type,
  93            std::vector<Attribute> outer_attrs, location_t locus)
  94     : outer_attrs (std::move (outer_attrs)),
  95       variables_pattern (std::move (variables_pattern)),
  96       type (std::move (type)), init_expr (std::move (init_expr)), locus (locus)
  97   {}
  98
  99   // Copy constructor with clone
 100   LetStmt (LetStmt const &other)
 101     : outer_attrs (other.outer_attrs), locus (other.locus)
 102   {
 103     // guard to prevent null dereference (only required if error state)
 104     if (other.variables_pattern != nullptr)
 105       variables_pattern = other.variables_pattern->clone_pattern ();
 106
 107     // guard to prevent null dereference (always required)
 108     if (other.init_expr != nullptr)
 109       init_expr = other.init_expr->clone_expr ();
 110     if (other.type != nullptr)
 111       type = other.type->clone_type ();
 112   }
 113
 114   // Overloaded assignment operator to clone
 115   LetStmt &operator= (LetStmt const &other)
 116   {
 117     outer_attrs = other.outer_attrs;
 118     locus = other.locus;
 119
 120     // guard to prevent null dereference (only required if error state)
 121     if (other.variables_pattern != nullptr)
 122       variables_pattern = other.variables_pattern->clone_pattern ();
 123     else
 124       variables_pattern = nullptr;
 125
 126     // guard to prevent null dereference (always required)
 127     if (other.init_expr != nullptr)
 128       init_expr = other.init_expr->clone_expr ();
 129     else
 130       init_expr = nullptr;
 131     if (other.type != nullptr)
 132       type = other.type->clone_type ();
 133     else
 134       type = nullptr;
 135
 136     return *this;
 137   }
 138
 139   // move constructors
 140   LetStmt (LetStmt &&other) = default;
 141   LetStmt &operator= (LetStmt &&other) = default;
 142
 143   location_t get_locus () const override final { return locus; }
 144
 145   void accept_vis (ASTVisitor &vis) override;
 146
 147   // Invalid if pattern is null, so base stripping on that.
 148   void mark_for_strip () override { variables_pattern = nullptr; }
 149   bool is_marked_for_strip () const override
 150   {
 151     return variables_pattern == nullptr;
 152   }
 153
 154   // TODO: this mutable getter seems really dodgy. Think up better way.
 155   std::vector<Attribute> &get_outer_attrs () { return outer_attrs; }
 156   const std::vector<Attribute> &get_outer_attrs () const { return outer_attrs; }
 157
 158   // TODO: is this better? Or is a "vis_block" better?
 159   Expr &get_init_expr ()
 160   {
 161     rust_assert (has_init_expr ());
 162     return *init_expr;
 163   }
 164
 165   std::unique_ptr<Expr> &get_init_expr_ptr ()
 166   {
 167     rust_assert (has_init_expr ());
 168     return init_expr;
 169   }
 170
 171   Pattern &get_pattern ()
 172   {
 173     rust_assert (variables_pattern != nullptr);
 174     return *variables_pattern;
 175   }
 176
 177   Type &get_type ()
 178   {
 179     rust_assert (has_type ());
 180     return *type;
 181   }
 182
 183   std::unique_ptr<Type> &get_type_ptr ()
 184   {
 185     rust_assert (has_type ());
 186     return type;
 187   }
 188
 189   bool is_item () const override final { return false; }
 190   Stmt::Kind get_stmt_kind () final { return Stmt::Kind::Let; }
 191
 192 protected:
 193   /* Use covariance to implement clone function as returning this object rather
 194    * than base */
 195   LetStmt *clone_stmt_impl () const override { return new LetStmt (*this); }
 196 };
 197
 198 // Expression statements (statements containing an expression)
 199 class ExprStmt : public Stmt
 200 {
 201   std::unique_ptr<Expr> expr;
 202   location_t locus;
 203   bool semicolon_followed;
 204
 205 public:
 206   location_t get_locus () const override final { return locus; }
 207
 208   bool is_item () const override final { return false; }
 209
 210   bool is_expr () const override final { return true; }
 211
 212   // Used for the last statement for statement macros with a trailing
 213   // semicolon.
 214   void add_semicolon () override final { semicolon_followed = true; }
 215
 216   std::string as_string () const override;
 217
 218   Stmt::Kind get_stmt_kind () final { return Stmt::Kind::Expr; }
 219
 220   std::vector<LetStmt *> locals;
 221
 222   ExprStmt (std::unique_ptr<Expr> &&expr, location_t locus,
 223             bool semicolon_followed)
 224     : expr (std::move (expr)), locus (locus),
 225       semicolon_followed (semicolon_followed)
 226   {}
 227
 228   // Copy constructor with clone
 229   ExprStmt (ExprStmt const &other)
 230     : locus (other.locus), semicolon_followed (other.semicolon_followed)
 231   {
 232     // guard to prevent null dereference (only required if error state)
 233     if (other.expr != nullptr)
 234       expr = other.expr->clone_expr ();
 235   }
 236
 237   // Overloaded assignment operator to clone
 238   ExprStmt &operator= (ExprStmt const &other)
 239   {
 240     Stmt::operator= (other);
 241
 242     // guard to prevent null dereference (only required if error state)
 243     if (other.expr != nullptr)
 244       expr = other.expr->clone_expr ();
 245     else
 246       expr = nullptr;
 247
 248     locus = other.locus;
 249     semicolon_followed = other.semicolon_followed;
 250
 251     return *this;
 252   }
 253
 254   // move constructors
 255   ExprStmt (ExprStmt &&other) = default;
 256   ExprStmt &operator= (ExprStmt &&other) = default;
 257
 258   void accept_vis (ASTVisitor &vis) override;
 259
 260   // Invalid if expr is null, so base stripping on that.
 261   void mark_for_strip () override { expr = nullptr; }
 262   bool is_marked_for_strip () const override { return expr == nullptr; }
 263
 264   // TODO: is this better? Or is a "vis_block" better?
 265   Expr &get_expr ()
 266   {
 267     rust_assert (expr != nullptr);
 268     return *expr;
 269   }
 270
 271   std::unique_ptr<Expr> &get_expr_ptr ()
 272   {
 273     rust_assert (expr != nullptr);
 274     return expr;
 275   }
 276
 277   std::unique_ptr<Expr> take_expr ()
 278   {
 279     rust_assert (expr != nullptr);
 280     return std::move (expr);
 281   }
 282
 283   bool is_semicolon_followed () const { return semicolon_followed; }
 284
 285 protected:
 286   /* Use covariance to implement clone function as returning this object rather
 287    * than base */
 288   ExprStmt *clone_stmt_impl () const override { return new ExprStmt (*this); }
 289 };
 290
 291 } // namespace AST
 292 } // namespace Rust
 293
 294 #endif