gccrs: Add HIR to GCC GENERIC lowering for all nodes

This patch implements the lowering mentioned in the previous patch for all HIR nodes.

	gcc/rust/
	* backend/rust-compile-block.cc: New.
	* backend/rust-compile-block.h: New.
	* backend/rust-compile-expr.cc: New.
	* backend/rust-compile-expr.h: New.
	* backend/rust-compile-extern.h: New.
	* backend/rust-compile-fnparam.cc: New.
	* backend/rust-compile-fnparam.h: New.
	* backend/rust-compile-implitem.cc: New.
	* backend/rust-compile-implitem.h: New.
	* backend/rust-compile-intrinsic.cc: New.
	* backend/rust-compile-intrinsic.h: New.
	* backend/rust-compile-item.cc: New.
	* backend/rust-compile-item.h: New.
	* backend/rust-compile-pattern.cc: New.
	* backend/rust-compile-pattern.h: New.
	* backend/rust-compile-resolve-path.cc: New.
	* backend/rust-compile-resolve-path.h: New.
	* backend/rust-compile-stmt.cc: New.
	* backend/rust-compile-stmt.h: New.
	* backend/rust-compile-struct-field-expr.cc: New.
	* backend/rust-compile-struct-field-expr.h: New.
	* backend/rust-compile-type.cc: New.
	* backend/rust-compile-type.h: New.
	* backend/rust-compile-var-decl.h: New.

Co-authored-by: David Faust <david.faust@oracle.com>

1 files changed, 515 insertions, 0 deletions

diff --git a/gcc/rust/backend/rust-compile-intrinsic.cc b/gcc/rust/backend/rust-compile-intrinsic.cc
new file mode 100644
index 0000000..61084b9
--- /dev/null
+++ b/gcc/rust/backend/rust-compile-intrinsic.cc
@@ -0,0 +1,515 @@
+// 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-compile-intrinsic.h"
+#include "fold-const.h"
+#include "langhooks.h"
+#include "rust-compile-context.h"
+#include "rust-compile-type.h"
+#include "rust-compile-fnparam.h"
+#include "rust-builtins.h"
+#include "rust-diagnostics.h"
+#include "rust-location.h"
+#include "rust-tree.h"
+#include "tree-core.h"
+#include "print-tree.h"
+
+namespace Rust {
+namespace Compile {
+
+static tree
+offset_handler (Context *ctx, TyTy::FnType *fntype);
+static tree
+sizeof_handler (Context *ctx, TyTy::FnType *fntype);
+static tree
+transmute_handler (Context *ctx, TyTy::FnType *fntype);
+static tree
+rotate_handler (Context *ctx, TyTy::FnType *fntype, tree_code op);
+static tree
+wrapping_op_handler (Context *ctx, TyTy::FnType *fntype, tree_code op);
+static tree
+copy_nonoverlapping_handler (Context *ctx, TyTy::FnType *fntype);
+
+static inline tree
+rotate_left_handler (Context *ctx, TyTy::FnType *fntype)
+{
+  return rotate_handler (ctx, fntype, LROTATE_EXPR);
+}
+static inline tree
+rotate_right_handler (Context *ctx, TyTy::FnType *fntype)
+{
+  return rotate_handler (ctx, fntype, RROTATE_EXPR);
+}
+
+static inline tree
+wrapping_add_handler (Context *ctx, TyTy::FnType *fntype)
+{
+  return wrapping_op_handler (ctx, fntype, PLUS_EXPR);
+}
+static inline tree
+wrapping_sub_handler (Context *ctx, TyTy::FnType *fntype)
+{
+  return wrapping_op_handler (ctx, fntype, MINUS_EXPR);
+}
+static inline tree
+wrapping_mul_handler (Context *ctx, TyTy::FnType *fntype)
+{
+  return wrapping_op_handler (ctx, fntype, MULT_EXPR);
+}
+
+static const std::map<std::string,
+		      std::function<tree (Context *, TyTy::FnType *)>>
+  generic_intrinsics = {{"offset", &offset_handler},
+			{"size_of", &sizeof_handler},
+			{"transmute", &transmute_handler},
+			{"rotate_left", &rotate_left_handler},
+			{"rotate_right", &rotate_right_handler},
+			{"wrapping_add", &wrapping_add_handler},
+			{"wrapping_sub", &wrapping_sub_handler},
+			{"wrapping_mul", &wrapping_mul_handler},
+			{"copy_nonoverlapping", &copy_nonoverlapping_handler}};
+
+Intrinsics::Intrinsics (Context *ctx) : ctx (ctx) {}
+
+tree
+Intrinsics::compile (TyTy::FnType *fntype)
+{
+  rust_assert (fntype->get_abi () == ABI::INTRINSIC);
+
+  tree builtin = error_mark_node;
+  BuiltinsContext &builtin_ctx = BuiltinsContext::get ();
+  if (builtin_ctx.lookup_simple_builtin (fntype->get_identifier (), &builtin))
+    return builtin;
+
+  // is it an generic builtin?
+  auto it = generic_intrinsics.find (fntype->get_identifier ());
+  if (it != generic_intrinsics.end ())
+    return it->second (ctx, fntype);
+
+  Location locus = ctx->get_mappings ()->lookup_location (fntype->get_ref ());
+  rust_error_at (locus, "unknown builtin intrinsic: %s",
+		 fntype->get_identifier ().c_str ());
+
+  return error_mark_node;
+}
+
+/**
+ * Items can be forward compiled which means we may not need to invoke this
+ * code. We might also have already compiled this generic function as well.
+ */
+static bool
+check_for_cached_intrinsic (Context *ctx, TyTy::FnType *fntype, tree *lookup)
+{
+  if (ctx->lookup_function_decl (fntype->get_ty_ref (), lookup,
+				 fntype->get_id (), fntype))
+    {
+      // Has this been added to the list? Then it must be finished
+      if (ctx->function_completed (*lookup))
+	{
+	  tree dummy = NULL_TREE;
+	  if (!ctx->lookup_function_decl (fntype->get_ty_ref (), &dummy))
+	    ctx->insert_function_decl (fntype, *lookup);
+	  return true;
+	}
+    }
+
+  return false;
+}
+
+/**
+ * Maybe override the Hir Lookups for the substituions in this context
+ */
+static void
+maybe_override_ctx (TyTy::FnType *fntype)
+{
+  if (fntype->has_subsititions_defined ())
+    fntype->override_context ();
+}
+
+/**
+ * Compile and setup a function's parameters
+ */
+static void
+compile_fn_params (Context *ctx, TyTy::FnType *fntype, tree fndecl,
+		   std::vector<Bvariable *> *compiled_param_variables,
+		   std::vector<tree_node *> *compiled_param_types = nullptr)
+{
+  for (auto &parm : fntype->get_params ())
+    {
+      auto &referenced_param = parm.first;
+      auto &param_tyty = parm.second;
+      auto compiled_param_type = TyTyResolveCompile::compile (ctx, param_tyty);
+
+      Location param_locus = referenced_param->get_locus ();
+      Bvariable *compiled_param_var
+	= CompileFnParam::compile (ctx, fndecl, referenced_param,
+				   compiled_param_type, param_locus);
+
+      compiled_param_variables->push_back (compiled_param_var);
+      if (compiled_param_types)
+	compiled_param_types->push_back (compiled_param_type);
+    }
+}
+
+static tree
+compile_intrinsic_function (Context *ctx, TyTy::FnType *fntype)
+{
+  maybe_override_ctx (fntype);
+
+  const Resolver::CanonicalPath &canonical_path = fntype->get_ident ().path;
+
+  tree compiled_fn_type = TyTyResolveCompile::compile (ctx, fntype);
+  std::string ir_symbol_name
+    = canonical_path.get () + fntype->subst_as_string ();
+  std::string asm_name = ctx->mangle_item (fntype, canonical_path);
+
+  unsigned int flags = 0;
+  tree fndecl
+    = ctx->get_backend ()->function (compiled_fn_type, ir_symbol_name, asm_name,
+				     flags, fntype->get_ident ().locus);
+
+  TREE_PUBLIC (fndecl) = 0;
+  TREE_READONLY (fndecl) = 1;
+  DECL_ARTIFICIAL (fndecl) = 1;
+  DECL_EXTERNAL (fndecl) = 0;
+  DECL_DECLARED_INLINE_P (fndecl) = 1;
+
+  return fndecl;
+}
+
+static void
+enter_intrinsic_block (Context *ctx, tree fndecl)
+{
+  tree enclosing_scope = NULL_TREE;
+  Location start_location = Location ();
+  Location end_location = Location ();
+
+  auto block = ctx->get_backend ()->block (fndecl, enclosing_scope, {},
+					   start_location, end_location);
+
+  ctx->push_block (block);
+}
+
+static void
+finalize_intrinsic_block (Context *ctx, tree fndecl)
+{
+  tree bind_tree = ctx->pop_block ();
+
+  gcc_assert (TREE_CODE (bind_tree) == BIND_EXPR);
+
+  DECL_SAVED_TREE (fndecl) = bind_tree;
+
+  ctx->push_function (fndecl);
+}
+
+static tree
+offset_handler (Context *ctx, TyTy::FnType *fntype)
+{
+  // offset intrinsic has two params dst pointer and offset isize
+  rust_assert (fntype->get_params ().size () == 2);
+
+  auto fndecl = compile_intrinsic_function (ctx, fntype);
+
+  std::vector<Bvariable *> param_vars;
+  compile_fn_params (ctx, fntype, fndecl, &param_vars);
+
+  auto &dst_param = param_vars.at (0);
+  auto &size_param = param_vars.at (1);
+  rust_assert (param_vars.size () == 2);
+  if (!ctx->get_backend ()->function_set_parameters (fndecl, param_vars))
+    return error_mark_node;
+
+  enter_intrinsic_block (ctx, fndecl);
+
+  // BUILTIN offset FN BODY BEGIN
+  tree dst = ctx->get_backend ()->var_expression (dst_param, Location ());
+  tree size = ctx->get_backend ()->var_expression (size_param, Location ());
+  tree pointer_offset_expr
+    = pointer_offset_expression (dst, size, BUILTINS_LOCATION);
+  auto return_statement
+    = ctx->get_backend ()->return_statement (fndecl, {pointer_offset_expr},
+					     Location ());
+  ctx->add_statement (return_statement);
+  // BUILTIN offset FN BODY END
+
+  finalize_intrinsic_block (ctx, fndecl);
+
+  return fndecl;
+}
+
+static tree
+sizeof_handler (Context *ctx, TyTy::FnType *fntype)
+{
+  // size_of has _zero_ parameters its parameter is the generic one
+  rust_assert (fntype->get_params ().size () == 0);
+
+  tree lookup = NULL_TREE;
+  if (check_for_cached_intrinsic (ctx, fntype, &lookup))
+    return lookup;
+
+  auto fndecl = compile_intrinsic_function (ctx, fntype);
+
+  // get the template parameter type tree fn size_of<T>();
+  rust_assert (fntype->get_num_substitutions () == 1);
+  auto &param_mapping = fntype->get_substs ().at (0);
+  const TyTy::ParamType *param_tyty = param_mapping.get_param_ty ();
+  TyTy::BaseType *resolved_tyty = param_tyty->resolve ();
+  tree template_parameter_type
+    = TyTyResolveCompile::compile (ctx, resolved_tyty);
+
+  enter_intrinsic_block (ctx, fndecl);
+
+  // BUILTIN size_of FN BODY BEGIN
+  tree size_expr = TYPE_SIZE_UNIT (template_parameter_type);
+  auto return_statement
+    = ctx->get_backend ()->return_statement (fndecl, {size_expr}, Location ());
+  ctx->add_statement (return_statement);
+  // BUILTIN size_of FN BODY END
+
+  finalize_intrinsic_block (ctx, fndecl);
+
+  return fndecl;
+}
+
+static tree
+transmute_handler (Context *ctx, TyTy::FnType *fntype)
+{
+  // transmute intrinsic has one parameter
+  rust_assert (fntype->get_params ().size () == 1);
+
+  tree lookup = NULL_TREE;
+  if (check_for_cached_intrinsic (ctx, fntype, &lookup))
+    return lookup;
+
+  auto fndecl = compile_intrinsic_function (ctx, fntype);
+
+  std::vector<Bvariable *> param_vars;
+  std::vector<tree_node *> compiled_types;
+  compile_fn_params (ctx, fntype, fndecl, &param_vars, &compiled_types);
+
+  if (!ctx->get_backend ()->function_set_parameters (fndecl, param_vars))
+    return error_mark_node;
+
+  // param to convert
+  Bvariable *convert_me_param = param_vars.at (0);
+  tree convert_me_expr
+    = ctx->get_backend ()->var_expression (convert_me_param, Location ());
+
+  // check for transmute pre-conditions
+  tree target_type_expr = TREE_TYPE (DECL_RESULT (fndecl));
+  tree source_type_expr = compiled_types.at (0);
+  tree target_size_expr = TYPE_SIZE (target_type_expr);
+  tree source_size_expr = TYPE_SIZE (source_type_expr);
+  // for some reason, unit types and other zero-sized types return NULL for the
+  // size expressions
+  unsigned HOST_WIDE_INT target_size
+    = target_size_expr ? TREE_INT_CST_LOW (target_size_expr) : 0;
+  unsigned HOST_WIDE_INT source_size
+    = source_size_expr ? TREE_INT_CST_LOW (source_size_expr) : 0;
+
+  // size check for concrete types
+  // TODO(liushuyu): check alignment for pointers; check for dependently-sized
+  // types
+  if (target_size != source_size)
+    {
+      rust_error_at (fntype->get_locus (),
+		     "cannot transmute between types of different sizes, or "
+		     "dependently-sized types");
+      rust_inform (fntype->get_ident ().locus, "source type: %qs (%lu bits)",
+		   fntype->get_params ().at (0).second->as_string ().c_str (),
+		   (unsigned long) source_size);
+      rust_inform (fntype->get_ident ().locus, "target type: %qs (%lu bits)",
+		   fntype->get_return_type ()->as_string ().c_str (),
+		   (unsigned long) target_size);
+    }
+
+  enter_intrinsic_block (ctx, fndecl);
+
+  // BUILTIN transmute FN BODY BEGIN
+
+  // Return *((orig_type*)&decl)  */
+
+  tree t
+    = build_fold_addr_expr_loc (Location ().gcc_location (), convert_me_expr);
+  t = fold_build1_loc (Location ().gcc_location (), NOP_EXPR,
+		       build_pointer_type (target_type_expr), t);
+  tree result_expr
+    = build_fold_indirect_ref_loc (Location ().gcc_location (), t);
+
+  auto return_statement
+    = ctx->get_backend ()->return_statement (fndecl, {result_expr},
+					     Location ());
+  ctx->add_statement (return_statement);
+  // BUILTIN transmute FN BODY END
+
+  finalize_intrinsic_block (ctx, fndecl);
+
+  return fndecl;
+}
+
+static tree
+rotate_handler (Context *ctx, TyTy::FnType *fntype, tree_code op)
+{
+  // rotate intrinsic has two parameter
+  rust_assert (fntype->get_params ().size () == 2);
+
+  tree lookup = NULL_TREE;
+  if (check_for_cached_intrinsic (ctx, fntype, &lookup))
+    return lookup;
+
+  auto fndecl = compile_intrinsic_function (ctx, fntype);
+
+  // setup the params
+  std::vector<Bvariable *> param_vars;
+  compile_fn_params (ctx, fntype, fndecl, &param_vars);
+
+  auto &x_param = param_vars.at (0);
+  auto &y_param = param_vars.at (1);
+  rust_assert (param_vars.size () == 2);
+  if (!ctx->get_backend ()->function_set_parameters (fndecl, param_vars))
+    return error_mark_node;
+
+  enter_intrinsic_block (ctx, fndecl);
+
+  // BUILTIN rotate FN BODY BEGIN
+  tree x = ctx->get_backend ()->var_expression (x_param, Location ());
+  tree y = ctx->get_backend ()->var_expression (y_param, Location ());
+  tree rotate_expr
+    = fold_build2_loc (BUILTINS_LOCATION, op, TREE_TYPE (x), x, y);
+  auto return_statement
+    = ctx->get_backend ()->return_statement (fndecl, {rotate_expr},
+					     Location ());
+  ctx->add_statement (return_statement);
+  // BUILTIN rotate FN BODY END
+
+  finalize_intrinsic_block (ctx, fndecl);
+
+  return fndecl;
+}
+
+/**
+ * pub fn wrapping_{add, sub, mul}<T>(lhs: T, rhs: T) -> T;
+ */
+static tree
+wrapping_op_handler (Context *ctx, TyTy::FnType *fntype, tree_code op)
+{
+  // wrapping_<op> intrinsics have two parameter
+  rust_assert (fntype->get_params ().size () == 2);
+
+  tree lookup = NULL_TREE;
+  if (check_for_cached_intrinsic (ctx, fntype, &lookup))
+    return lookup;
+
+  auto fndecl = compile_intrinsic_function (ctx, fntype);
+
+  // setup the params
+  std::vector<Bvariable *> param_vars;
+  compile_fn_params (ctx, fntype, fndecl, &param_vars);
+
+  auto &lhs_param = param_vars.at (0);
+  auto &rhs_param = param_vars.at (1);
+
+  if (!ctx->get_backend ()->function_set_parameters (fndecl, param_vars))
+    return error_mark_node;
+
+  enter_intrinsic_block (ctx, fndecl);
+
+  // BUILTIN wrapping_<op> FN BODY BEGIN
+  auto lhs = ctx->get_backend ()->var_expression (lhs_param, Location ());
+  auto rhs = ctx->get_backend ()->var_expression (rhs_param, Location ());
+
+  // Operations are always wrapping in Rust, as we have -fwrapv enabled by
+  // default. The difference between a wrapping_{add, sub, mul} and a regular
+  // arithmetic operation is that these intrinsics do not panic - they always
+  // carry over.
+  auto wrap_expr = build2 (op, TREE_TYPE (lhs), lhs, rhs);
+
+  auto return_statement
+    = ctx->get_backend ()->return_statement (fndecl, {wrap_expr}, Location ());
+  ctx->add_statement (return_statement);
+  // BUILTIN wrapping_<op> FN BODY END
+
+  finalize_intrinsic_block (ctx, fndecl);
+
+  return fndecl;
+}
+
+/**
+ * fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: usize);
+ */
+static tree
+copy_nonoverlapping_handler (Context *ctx, TyTy::FnType *fntype)
+{
+  rust_assert (fntype->get_params ().size () == 3);
+  rust_assert (fntype->get_num_substitutions () == 1);
+
+  tree lookup = NULL_TREE;
+  if (check_for_cached_intrinsic (ctx, fntype, &lookup))
+    return lookup;
+
+  auto fndecl = compile_intrinsic_function (ctx, fntype);
+
+  // Most intrinsic functions are pure - not `copy_nonoverlapping`
+  TREE_READONLY (fndecl) = 0;
+  TREE_SIDE_EFFECTS (fndecl) = 1;
+
+  // setup the params
+  std::vector<Bvariable *> param_vars;
+  compile_fn_params (ctx, fntype, fndecl, &param_vars);
+
+  if (!ctx->get_backend ()->function_set_parameters (fndecl, param_vars))
+    return error_mark_node;
+
+  enter_intrinsic_block (ctx, fndecl);
+
+  // BUILTIN copy_nonoverlapping BODY BEGIN
+
+  auto src = ctx->get_backend ()->var_expression (param_vars[0], Location ());
+  auto dst = ctx->get_backend ()->var_expression (param_vars[1], Location ());
+  auto count = ctx->get_backend ()->var_expression (param_vars[2], Location ());
+
+  // We want to create the following statement
+  // memcpy(dst, src, size_of::<T>());
+  // so
+  // memcpy(dst, src, size_expr);
+
+  auto *resolved_ty = fntype->get_substs ().at (0).get_param_ty ()->resolve ();
+  auto param_type = TyTyResolveCompile::compile (ctx, resolved_ty);
+
+  tree size_expr
+    = build2 (MULT_EXPR, size_type_node, TYPE_SIZE_UNIT (param_type), count);
+
+  tree memcpy_raw = nullptr;
+  BuiltinsContext::get ().lookup_simple_builtin ("memcpy", &memcpy_raw);
+  rust_assert (memcpy_raw);
+  auto memcpy
+    = build_fold_addr_expr_loc (Location ().gcc_location (), memcpy_raw);
+
+  auto copy_call
+    = ctx->get_backend ()->call_expression (memcpy, {dst, src, size_expr},
+					    nullptr, Location ());
+
+  ctx->add_statement (copy_call);
+
+  // BUILTIN copy_nonoverlapping BODY END
+
+  finalize_intrinsic_block (ctx, fndecl);
+
+  return fndecl;
+}
+
+} // namespace Compile
+} // namespace Rust