Merge from trunk revision aa8f4242efc99f24de73c59d53996f28db28c13f.

1 files changed, 467 insertions, 0 deletions

diff --git a/gcc/rust/rust-lang.cc b/gcc/rust/rust-lang.cc
new file mode 100644
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+++ b/gcc/rust/rust-lang.cc
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+// Copyright (C) 2020-2023 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include "rust-system.h"
+#include "rust-diagnostics.h"
+#include "coretypes.h"
+#include "target.h"
+#include "tree.h"
+#include "gimple-expr.h"
+#include "diagnostic.h"
+#include "opts.h"
+#include "fold-const.h"
+#include "gimplify.h"
+#include "stor-layout.h"
+#include "debug.h"
+#include "convert.h"
+#include "langhooks.h"
+#include "langhooks-def.h"
+#include "selftest.h"
+#include "rust-cfg-parser.h"
+#include "rust-privacy-ctx.h"
+#include "rust-ast-resolve-item.h"
+#include "rust-optional.h"
+
+#include <mpfr.h>
+// note: header files must be in this order or else forward declarations don't
+// work properly. Kinda dumb system, but have to live with it. clang-format
+// seems to mess it up
+/* Order: config, system, coretypes, target, tree, gimple-expr, diagnostic,
+ * opts, fold-const, gimplify, stor-layout, debug, convert, langhooks,
+ * langhooks-def */
+
+// FIXME: test saving intellisense
+#include "options.h"
+
+// version check to stop compiling if c++ isn't c++11 or higher
+#if __cplusplus < 201103
+#error                                                                         \
+  "GCC Rust frontend requires C++11 or higher. You can compile the g++ frontend first and then compile the Rust frontend using that."
+#endif
+// TODO: is this best way to do it? Is it allowed? (should be)
+
+/* General TODOs:
+ *  - convert all copies of expensive-to-copy (deep copy) AST objects into
+ * moves, if possible. Don't remove clone functionality - it may be required for
+ * e.g. HIR conversion.
+ */
+
+#include "rust-session-manager.h"
+
+// Language-dependent contents of a type. GTY() mark used for garbage collector.
+struct GTY (()) lang_type
+{
+};
+
+// Language-dependent contents of a decl.
+struct GTY (()) lang_decl
+{
+};
+
+// Language-dependent contents of an identifier.  This must include a
+// tree_identifier.
+struct GTY (()) lang_identifier
+{
+  struct tree_identifier common;
+};
+
+// The resulting tree type.
+union GTY ((
+  desc ("TREE_CODE (&%h.generic) == IDENTIFIER_NODE"),
+  chain_next (
+    "CODE_CONTAINS_STRUCT (TREE_CODE (&%h.generic), "
+    "TS_COMMON) ? ((union lang_tree_node *) TREE_CHAIN (&%h.generic)) : NULL")))
+  lang_tree_node
+{
+  union tree_node GTY ((tag ("0"), desc ("tree_node_structure (&%h)"))) generic;
+  struct lang_identifier GTY ((tag ("1"))) identifier;
+};
+
+// We don't use language_function.
+struct GTY (()) language_function
+{
+};
+
+// has to be in same compilation unit as session, so here for now
+void
+rust_add_target_info (const char *key, const char *value)
+{
+  sorry ("TODO");
+
+  Rust::Session::get_instance ().options.target_data.insert_key_value_pair (
+    key, value);
+}
+
+/* Language hooks.  */
+
+/* Initial lang hook called (possibly), used for initialisation.
+ * Must call build_common_tree_nodes, set_sizetype, build_common_tree_nodes_2,
+ * and build_common_builtin_nodes, as well as set global variable
+ * void_list_node. Apparently called after option handling? */
+static bool
+grs_langhook_init (void)
+{
+  /* Something to do with this:
+   This allows the code in d-builtins.cc to not have to worry about
+   converting (C signed char *) to (D char *) for string arguments of
+   built-in functions. The parameter (signed_char = false) specifies
+   whether char is signed.  */
+  build_common_tree_nodes (false);
+
+  // Builds built-ins for middle-end after all front-end built-ins are already
+  // instantiated
+  build_common_builtin_nodes ();
+
+  mpfr_set_default_prec (128);
+
+  using_eh_for_cleanups ();
+
+  // initialise compiler session
+  Rust::Session::get_instance ().init ();
+
+  return true;
+}
+
+/* The option mask (something to do with options for specific frontends or
+ * something). */
+static unsigned int
+grs_langhook_option_lang_mask (void)
+{
+  return CL_Rust;
+}
+
+/* Initialize the options structure. */
+static void
+grs_langhook_init_options_struct (struct gcc_options *opts)
+{
+  /* Operations are always wrapping in Rust, even on signed integer. This is
+   * useful for the low level wrapping_{add, sub, mul} intrinsics, not for
+   * regular arithmetic operations which are checked for overflow anyway using
+   * builtins */
+  opts->x_flag_wrapv = 1;
+
+  /* We need to warn on unused variables by default */
+  opts->x_warn_unused_variable = 1;
+  /* For const variables too */
+  opts->x_warn_unused_const_variable = 1;
+  /* And finally unused result for #[must_use] */
+  opts->x_warn_unused_result = 1;
+
+  // nothing yet - used by frontends to change specific options for the language
+  Rust::Session::get_instance ().init_options ();
+}
+
+/* Main entry point for front-end, apparently. Finds input file names in global
+ * vars in_fnames and num_in_fnames. From this, frontend can take over and do
+ * actual parsing and initial compilation. This function must create a complete
+ * parse tree in a global var, and then return.
+ *
+ * Some consider this the "start of compilation". */
+static void
+grs_langhook_parse_file (void)
+{
+  rust_debug ("Preparing to parse files. ");
+
+  Rust::Session::get_instance ().handle_input_files (num_in_fnames, in_fnames);
+}
+
+/* Seems to get the exact type for a specific type - e.g. for scalar float with
+ * 32-bit bitsize, it returns float, and for 64-bit bitsize, it returns double.
+ * Used to map RTL nodes to machine modes or something like that. */
+static tree
+grs_langhook_type_for_mode (machine_mode mode, int unsignedp)
+{
+  // TODO: change all this later to match rustc types
+  if (mode == TYPE_MODE (float_type_node))
+    return float_type_node;
+
+  if (mode == TYPE_MODE (double_type_node))
+    return double_type_node;
+
+  if (mode == TYPE_MODE (intQI_type_node)) // quarter integer mode - single byte
+					   // treated as integer
+    return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
+  if (mode
+      == TYPE_MODE (intHI_type_node)) // half integer mode - two-byte integer
+    return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
+  if (mode
+      == TYPE_MODE (intSI_type_node)) // single integer mode - four-byte integer
+    return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
+  if (mode
+      == TYPE_MODE (
+	intDI_type_node)) // double integer mode - eight-byte integer
+    return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
+  if (mode
+      == TYPE_MODE (intTI_type_node)) // tetra integer mode - 16-byte integer
+    return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
+
+  if (mode == TYPE_MODE (integer_type_node))
+    return unsignedp ? unsigned_type_node : integer_type_node;
+
+  if (mode == TYPE_MODE (long_integer_type_node))
+    return unsignedp ? long_unsigned_type_node : long_integer_type_node;
+
+  if (mode == TYPE_MODE (long_long_integer_type_node))
+    return unsignedp ? long_long_unsigned_type_node
+		     : long_long_integer_type_node;
+
+  if (COMPLEX_MODE_P (mode))
+    {
+      if (mode == TYPE_MODE (complex_float_type_node))
+	return complex_float_type_node;
+      if (mode == TYPE_MODE (complex_double_type_node))
+	return complex_double_type_node;
+      if (mode == TYPE_MODE (complex_long_double_type_node))
+	return complex_long_double_type_node;
+      if (mode == TYPE_MODE (complex_integer_type_node) && !unsignedp)
+	return complex_integer_type_node;
+    }
+
+  /* See (a) <https://github.com/Rust-GCC/gccrs/issues/1713>
+     "Test failure on msp430-elfbare target", and
+     (b) <https://gcc.gnu.org/PR46805>
+     "ICE: SIGSEGV in optab_for_tree_code (optabs.c:407) with -O -fno-tree-scev-cprop -ftree-vectorize"
+     -- we have to support "random" modes/types here.
+     TODO Clean all this up (either locally, or preferably per PR46805:
+     "Ideally we'd never use lang_hooks.types.type_for_mode (or _for_size) in the
+     middle-end but had a pure middle-end based implementation".  */
+  for (size_t i = 0; i < NUM_INT_N_ENTS; i ++)
+    if (int_n_enabled_p[i]
+	&& mode == int_n_data[i].m)
+      return (unsignedp ? int_n_trees[i].unsigned_type
+	      : int_n_trees[i].signed_type);
+
+  /* gcc_unreachable */
+  return NULL;
+}
+
+// Record a builtin function. We just ignore builtin functions.
+static tree
+grs_langhook_builtin_function (tree decl ATTRIBUTE_UNUSED)
+{
+  return decl;
+}
+
+/* Return true if we are in the global binding level (which is never,
+ * apparently). */
+static bool
+grs_langhook_global_bindings_p (void)
+{
+  // return current_function_decl == NULL_TREE;
+  // gcc_unreachable();
+  // return true;
+  return false;
+}
+
+/* Push a declaration into the current binding level.  We can't
+   usefully implement this since we don't want to convert from tree
+   back to one of our internal data structures.  I think the only way
+   this is used is to record a decl which is to be returned by
+   getdecls, and we could implement it for that purpose if
+   necessary.  */
+static tree
+grs_langhook_pushdecl (tree decl ATTRIBUTE_UNUSED)
+{
+  gcc_unreachable ();
+  return NULL;
+}
+
+/* This hook is used to get the current list of declarations as trees.
+   We don't support that; instead we use the write_globals hook.  This
+   can't simply crash because it is called by -gstabs.  */
+static tree
+grs_langhook_getdecls (void)
+{
+  // gcc_unreachable();
+  return NULL;
+}
+
+// Handle Rust-specific options. Return false if nothing happened.
+static bool
+grs_langhook_handle_option (
+  size_t scode, const char *arg, HOST_WIDE_INT value, int kind ATTRIBUTE_UNUSED,
+  location_t loc ATTRIBUTE_UNUSED,
+  const struct cl_option_handlers *handlers ATTRIBUTE_UNUSED)
+{
+  // Convert integer code to lang.opt enum codes with names.
+  enum opt_code code = (enum opt_code) scode;
+
+  // Delegate to session manager
+  return Rust::Session::get_instance ().handle_option (code, arg, value, kind,
+						       loc, handlers);
+}
+
+/* Run after parsing options.  */
+static bool
+grs_langhook_post_options (const char **pfilename ATTRIBUTE_UNUSED)
+{
+  // can be used to override other options if required
+
+  // satisfies an assert in init_excess_precision in toplev.cc
+  if (flag_excess_precision /*_cmdline*/ == EXCESS_PRECISION_DEFAULT)
+    flag_excess_precision /*_cmdline*/ = EXCESS_PRECISION_STANDARD;
+
+  /* Returning false means that the backend should be used.  */
+  return false;
+}
+
+/* Rust-specific gimplification. May need to gimplify e.g.
+ * CALL_EXPR_STATIC_CHAIN */
+static int
+grs_langhook_gimplify_expr (tree *expr_p ATTRIBUTE_UNUSED,
+			    gimple_seq *pre_p ATTRIBUTE_UNUSED,
+			    gimple_seq *post_p ATTRIBUTE_UNUSED)
+{
+  if (TREE_CODE (*expr_p) == CALL_EXPR
+      && CALL_EXPR_STATIC_CHAIN (*expr_p) != NULL_TREE)
+    gimplify_expr (&CALL_EXPR_STATIC_CHAIN (*expr_p), pre_p, post_p,
+		   is_gimple_val, fb_rvalue);
+  return GS_UNHANDLED;
+}
+
+static tree
+grs_langhook_eh_personality (void)
+{
+  static tree personality_decl;
+  if (personality_decl == NULL_TREE)
+    {
+      personality_decl = build_personality_function ("gccrs");
+      rust_preserve_from_gc (personality_decl);
+    }
+  return personality_decl;
+}
+
+tree
+convert (tree type, tree expr)
+{
+  if (type == error_mark_node || expr == error_mark_node
+      || TREE_TYPE (expr) == error_mark_node)
+    return error_mark_node;
+
+  if (type == TREE_TYPE (expr))
+    return expr;
+
+  if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (expr)))
+    return fold_convert (type, expr);
+
+  switch (TREE_CODE (type))
+    {
+    case VOID_TYPE:
+    case BOOLEAN_TYPE:
+      return fold_convert (type, expr);
+    case INTEGER_TYPE:
+      return convert_to_integer (type, expr);
+    case POINTER_TYPE:
+      return convert_to_pointer (type, expr);
+    case REAL_TYPE:
+      return convert_to_real (type, expr);
+    case COMPLEX_TYPE:
+      return convert_to_complex (type, expr);
+    default:
+      break;
+    }
+
+  gcc_unreachable ();
+}
+
+/* FIXME: This is a hack to preserve trees that we create from the
+   garbage collector.  */
+
+static GTY (()) tree rust_gc_root;
+
+void
+rust_preserve_from_gc (tree t)
+{
+  rust_gc_root = tree_cons (NULL_TREE, t, rust_gc_root);
+}
+
+/* Convert an identifier for use in an error message.  */
+
+const char *
+rust_localize_identifier (const char *ident)
+{
+  return identifier_to_locale (ident);
+}
+
+/* The language hooks data structure. This is the main interface between the GCC
+ * front-end and the GCC middle-end/back-end. A list of language hooks could be
+ * found in <gcc>/langhooks.h
+ */
+#undef LANG_HOOKS_NAME
+#undef LANG_HOOKS_INIT
+#undef LANG_HOOKS_OPTION_LANG_MASK
+#undef LANG_HOOKS_INIT_OPTIONS_STRUCT
+#undef LANG_HOOKS_HANDLE_OPTION
+#undef LANG_HOOKS_POST_OPTIONS
+#undef LANG_HOOKS_PARSE_FILE
+#undef LANG_HOOKS_TYPE_FOR_MODE
+#undef LANG_HOOKS_BUILTIN_FUNCTION
+#undef LANG_HOOKS_GLOBAL_BINDINGS_P
+#undef LANG_HOOKS_PUSHDECL
+#undef LANG_HOOKS_GETDECLS
+#undef LANG_HOOKS_WRITE_GLOBALS
+#undef LANG_HOOKS_GIMPLIFY_EXPR
+#undef LANG_HOOKS_EH_PERSONALITY
+
+#define LANG_HOOKS_NAME "GNU Rust"
+#define LANG_HOOKS_INIT grs_langhook_init
+#define LANG_HOOKS_OPTION_LANG_MASK grs_langhook_option_lang_mask
+#define LANG_HOOKS_INIT_OPTIONS_STRUCT grs_langhook_init_options_struct
+#define LANG_HOOKS_HANDLE_OPTION grs_langhook_handle_option
+#define LANG_HOOKS_POST_OPTIONS grs_langhook_post_options
+/* Main lang-hook, apparently. Finds input file names in global vars in_fnames
+ * and num_in_fnames From this, frontend can take over and do actual parsing and
+ * initial compilation.
+ * This hook must create a complete parse tree in a global var, and then return.
+ */
+#define LANG_HOOKS_PARSE_FILE grs_langhook_parse_file
+#define LANG_HOOKS_TYPE_FOR_MODE grs_langhook_type_for_mode
+#define LANG_HOOKS_BUILTIN_FUNCTION grs_langhook_builtin_function
+#define LANG_HOOKS_GLOBAL_BINDINGS_P grs_langhook_global_bindings_p
+#define LANG_HOOKS_PUSHDECL grs_langhook_pushdecl
+#define LANG_HOOKS_GETDECLS grs_langhook_getdecls
+#define LANG_HOOKS_GIMPLIFY_EXPR grs_langhook_gimplify_expr
+#define LANG_HOOKS_EH_PERSONALITY grs_langhook_eh_personality
+
+#if CHECKING_P
+
+#undef LANG_HOOKS_RUN_LANG_SELFTESTS
+#define LANG_HOOKS_RUN_LANG_SELFTESTS selftest::run_rust_tests
+
+namespace selftest {
+
+void
+run_rust_tests ()
+{
+  // Call tests for the rust frontend here
+  rust_cfg_parser_test ();
+  rust_privacy_ctx_test ();
+  rust_crate_name_validation_test ();
+  rust_simple_path_resolve_test ();
+  rust_optional_test ();
+}
+} // namespace selftest
+
+#endif /* !CHECKING_P */
+
+// Expands all LANG_HOOKS_x of GCC
+struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER;
+
+// These are for GCC's garbage collector to work properly or something
+#include "gt-rust-rust-lang.h"
+#include "gtype-rust.h"