gccrs: Refactor HIR to reduce the amount of raw pointers

gccrs: Refactor HIR to reduce the amount of raw pointers

Attempt to use references and smart pointers whenever possible.

gcc/rust/ChangeLog:

	* backend/rust-compile-base.cc (HIRCompileBase::compile_function_body):
	Remove usage of get function to retrieve a raw pointer.
	* backend/rust-compile-base.h:
	Change API usage from raw pointer to a reference.
	* backend/rust-compile-block.cc (CompileBlock::compile): Likewise.
	(CompileBlock::visit): Likewise.
	(CompileConditionalBlocks::visit): Likewise.
	* backend/rust-compile-block.h: Likewise.
	* backend/rust-compile-expr.cc (CompileExpr::Compile): Likewise.
	(CompileExpr::visit): Likewise.
	(check_match_scrutinee): Likewise.
	(CompileExpr::array_value_expr): Likewise.
	(CompileExpr::array_copied_expr): Likewise.
	(CompileExpr::generate_closure_function): Likewise.
	(CompileExpr::generate_possible_fn_trait_call): Likewise.
	* backend/rust-compile-expr.h: Likewise.
	* backend/rust-compile-fnparam.cc (CompileFnParam::compile): Likewise.
	(CompileFnParam::visit): Likewise.
	* backend/rust-compile-fnparam.h: Likewise.
	* backend/rust-compile-implitem.cc (CompileTraitItem::visit): Likewise.
	* backend/rust-compile-intrinsic.cc (compile_fn_params): Likewise.
	* backend/rust-compile-item.cc (CompileItem::visit): Likewise.
	* backend/rust-compile-pattern.cc (CompilePatternCheckExpr::visit):
	Likewise.
	(compile_range_pattern_bound): Likewise.
	(CompilePatternBindings::visit): Likewise.
	(CompilePatternLet::visit): Likewise.
	* backend/rust-compile-pattern.h: Likewise.
	* backend/rust-compile-resolve-path.cc (ResolvePathRef::resolve):
	Likewise.
	(HIRCompileBase::query_compile): Likewise.
	* backend/rust-compile-stmt.cc (CompileStmt::visit): Likewise.
	* backend/rust-compile-struct-field-expr.cc (CompileStructExprField::Compile):
	Likewise.
	(CompileStructExprField::visit): Likewise.
	* backend/rust-compile-struct-field-expr.h: Likewise.
	* backend/rust-compile-type.cc (TyTyResolveCompile::visit): Likewise.
	* backend/rust-compile-var-decl.h: Likewise.
	* backend/rust-compile.cc: Likewise.
	* backend/rust-mangle-v0.cc (v0_inherent_or_trait_impl_path): Likewise.
	* checks/errors/borrowck/rust-bir-builder-expr-stmt.cc (ExprStmtBuilder::visit):
	Likewise.
	* checks/errors/borrowck/rust-bir-builder-lazyboolexpr.h: Likewise.
	* checks/errors/borrowck/rust-bir-builder-pattern.h: Likewise.
	* checks/errors/borrowck/rust-bir-builder-struct.h: Likewise.
	* checks/errors/borrowck/rust-bir-builder.h: Likewise.
	* checks/errors/borrowck/rust-function-collector.h: Likewise.
	* checks/errors/privacy/rust-privacy-reporter.cc (PrivacyReporter::check_type_privacy):
	Likewise.
	(PrivacyReporter::visit): Likewise.
	* checks/errors/privacy/rust-privacy-reporter.h: Likewise.
	* checks/errors/privacy/rust-reachability.cc (ReachabilityVisitor::visit):
	Likewise.
	* checks/errors/rust-const-checker.cc (ConstChecker::visit): Likewise.
	* checks/errors/rust-unsafe-checker.cc (UnsafeChecker::visit):
	Likewise.
	* checks/lints/rust-lint-marklive.cc (MarkLive::visit): Likewise.
	* checks/lints/rust-lint-marklive.h: Likewise.
	* hir/rust-hir-dump.cc (Dump::visit): Likewise.
	* hir/tree/rust-hir-expr.h: Likewise.
	* hir/tree/rust-hir-item.h: Likewise.
	* hir/tree/rust-hir-path.h: Likewise.
	* hir/tree/rust-hir-pattern.h: Likewise.
	* hir/tree/rust-hir-stmt.h: Likewise.
	* hir/tree/rust-hir-type.h: Likewise.
	* hir/tree/rust-hir.h: Likewise.
	* typecheck/rust-autoderef.cc: Likewise.
	* typecheck/rust-hir-dot-operator.cc (MethodResolver::select):
	Likewise.
	* typecheck/rust-hir-inherent-impl-overlap.h: Likewise.
	* typecheck/rust-hir-path-probe.cc (PathProbeType::process_impl_item_candidate):
	Likewise.
	(PathProbeImplTrait::process_trait_impl_items_for_candidates): Likewise.
	* typecheck/rust-hir-trait-resolve.cc (TraitResolver::resolve_trait):
	Likewise.
	(TraitItemReference::resolve_item): Likewise.
	* typecheck/rust-hir-type-check-base.cc: Likewise.
	* typecheck/rust-hir-type-check-base.h: Likewise.
	* typecheck/rust-hir-type-check-enumitem.cc (TypeCheckEnumItem::Resolve):
	Likewise.
	(TypeCheckEnumItem::visit): Likewise.
	* typecheck/rust-hir-type-check-enumitem.h: Likewise.
	* typecheck/rust-hir-type-check-expr.cc (TypeCheckExpr::Resolve):
	Likewise.
	(TypeCheckExpr::visit): Likewise.
	(TypeCheckExpr::resolve_fn_trait_call): Likewise.
	* typecheck/rust-hir-type-check-expr.h: Likewise.
	* typecheck/rust-hir-type-check-implitem.cc (TypeCheckTopLevelExternItem::Resolve):
	Likewise.
	(TypeCheckTopLevelExternItem::visit): Likewise.
	(TypeCheckImplItem::visit): Likewise.
	(TypeCheckImplItemWithTrait::visit): Likewise.
	* typecheck/rust-hir-type-check-implitem.h: Likewise.
	* typecheck/rust-hir-type-check-item.cc (TypeCheckItem::visit): Likewise.
	(TypeCheckItem::resolve_impl_item): Likewise.
	(TypeCheckItem::resolve_impl_block_substitutions): Likewise.
	(TypeCheckItem::resolve_impl_block_self): Likewise.
	* typecheck/rust-hir-type-check-path.cc (TypeCheckExpr::visit): Likewise.
	(TypeCheckExpr::resolve_segments): Likewise.
	* typecheck/rust-hir-type-check-pattern.cc (TypeCheckPattern::Resolve):
	Likewise.
	(TypeCheckPattern::visit): Likewise.
	(ClosureParamInfer::Resolve): Likewise.
	(ClosureParamInfer::visit): Likewise.
	* typecheck/rust-hir-type-check-pattern.h: Likewise.
	* typecheck/rust-hir-type-check-stmt.cc (TypeCheckStmt::Resolve):
	Likewise.
	(TypeCheckStmt::visit): Likewise.
	* typecheck/rust-hir-type-check-stmt.h: Likewise.
	* typecheck/rust-hir-type-check-struct-field.h: Likewise.
	* typecheck/rust-hir-type-check-struct.cc (TypeCheckStructExpr::TypeCheckStructExpr):
	Likewise.
	(TypeCheckStructExpr::Resolve): Likewise.
	(TypeCheckStructExpr::resolve): Likewise.
	(TypeCheckStructExpr::visit): Likewise.
	* typecheck/rust-hir-type-check-type.cc (TypeCheckResolveGenericArguments::resolve):
	Likewise.
	(TypeCheckType::Resolve): Likewise.
	(TypeCheckType::visit): Likewise.
	(TypeCheckType::resolve_root_path): Likewise.
	(TypeResolveGenericParam::Resolve): Likewise.
	(TypeResolveGenericParam::visit): Likewise.
	(ResolveWhereClauseItem::visit): Likewise.
	* typecheck/rust-hir-type-check-type.h: Likewise.
	* typecheck/rust-hir-type-check.cc (TraitItemReference::get_type_from_fn):
	Likewise.
	* typecheck/rust-hir-type-check.h: Likewise.
	* typecheck/rust-type-util.cc (query_type): Likewise.
	* typecheck/rust-typecheck-context.cc (TypeCheckContextItem::TypeCheckContextItem):
	Likewise.
	* typecheck/rust-tyty-bounds.cc (TypeBoundsProbe::scan): Likewise.
	(TypeCheckBase::get_predicate_from_bound): Likewise.
	* typecheck/rust-tyty-call.cc (TypeCheckCallExpr::visit): Likewise.
	(TypeCheckMethodCallExpr::go): Likewise.
	(TypeCheckMethodCallExpr::check): Likewise.
	* typecheck/rust-tyty-subst.cc: Likewise.
	* typecheck/rust-tyty.cc (BaseType::monomorphized_clone): Likewise.
	(VariantDef::VariantDef): Remove copy constructor.
	(VariantDef::operator=): Change to move operator.
	(VariantDef::get_discriminant): Replace return type to a reference
	instead of a reference to a unique pointer.
	(VariantDef::clone): Change to references.
	(VariantDef::monomorphized_clone): Likewise.
	(FnType::as_string): Likewise.
	(FnType::clone): Likewise.
	* typecheck/rust-tyty.h: Likewise.
	* util/rust-hir-map.cc (Mappings::insert_hir_impl_block): Likewise.
	* backend/rust-compile-asm.cc: Use a reference instead of the raw
	pointer value.
	* checks/errors/borrowck/rust-bir-builder-pattern.cc: Use references.
	* checks/errors/rust-hir-pattern-analysis.cc: Likewise.

Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>