// Copyright (C) 2020-2025 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-ast-visitor.h"
#include "rust-system.h"
#include "rust-session-manager.h"
#include "rust-attributes.h"
#include "rust-ast.h"
#include "rust-ast-full.h"
#include "rust-diagnostics.h"
#include "rust-unicode.h"
#include "rust-attribute-values.h"

namespace Rust {
namespace Analysis {

using Attrs = Values::Attributes;

// https://doc.rust-lang.org/stable/nightly-rustc/src/rustc_feature/builtin_attrs.rs.html#248
static const BuiltinAttrDefinition __definitions[]
  = {{Attrs::INLINE, CODE_GENERATION},
     {Attrs::COLD, CODE_GENERATION},
     {Attrs::CFG, EXPANSION},
     {Attrs::CFG_ATTR, EXPANSION},
     {Attrs::DEPRECATED, STATIC_ANALYSIS},
     {Attrs::ALLOW, STATIC_ANALYSIS},
     {Attrs::ALLOW_INTERNAL_UNSTABLE, STATIC_ANALYSIS},
     {Attrs::DOC, HIR_LOWERING},
     {Attrs::MUST_USE, STATIC_ANALYSIS},
     {Attrs::LANG, HIR_LOWERING},
     {Attrs::LINK_SECTION, CODE_GENERATION},
     {Attrs::NO_MANGLE, CODE_GENERATION},
     {Attrs::REPR, CODE_GENERATION},
     {Attrs::RUSTC_BUILTIN_MACRO, EXPANSION},
     {Attrs::PATH, EXPANSION},
     {Attrs::MACRO_USE, NAME_RESOLUTION},
     {Attrs::MACRO_EXPORT, NAME_RESOLUTION},
     {Attrs::PROC_MACRO, EXPANSION},
     {Attrs::PROC_MACRO_DERIVE, EXPANSION},
     {Attrs::PROC_MACRO_ATTRIBUTE, EXPANSION},
     // FIXME: This is not implemented yet, see
     // https://github.com/Rust-GCC/gccrs/issues/1475
     {Attrs::TARGET_FEATURE, CODE_GENERATION},
     // From now on, these are reserved by the compiler and gated through
     // #![feature(rustc_attrs)]
     {Attrs::RUSTC_DEPRECATED, STATIC_ANALYSIS},
     {Attrs::RUSTC_INHERIT_OVERFLOW_CHECKS, CODE_GENERATION},
     {Attrs::STABLE, STATIC_ANALYSIS},
     {Attrs::UNSTABLE, STATIC_ANALYSIS},
     // assuming we keep these for static analysis
     {Attrs::RUSTC_CONST_STABLE, STATIC_ANALYSIS},
     {Attrs::RUSTC_CONST_UNSTABLE, STATIC_ANALYSIS}};

BuiltinAttributeMappings *
BuiltinAttributeMappings::get ()
{
  static BuiltinAttributeMappings *instance = nullptr;
  if (instance == nullptr)
    instance = new BuiltinAttributeMappings ();

  return instance;
}

const BuiltinAttrDefinition &
BuiltinAttributeMappings::lookup_builtin (const std::string &attr_name) const
{
  auto it = mappings.find (attr_name);
  if (it == mappings.end ())
    return BuiltinAttrDefinition::error_node ();

  return it->second;
}

BuiltinAttributeMappings::BuiltinAttributeMappings ()
{
  size_t ndefinitions = sizeof (__definitions) / sizeof (BuiltinAttrDefinition);
  for (size_t i = 0; i < ndefinitions; i++)
    {
      const BuiltinAttrDefinition &def = __definitions[i];
      mappings.insert ({def.name, def});
    }
}

AttributeChecker::AttributeChecker () {}

void
AttributeChecker::go (AST::Crate &crate)
{
  visit (crate);
}

void
AttributeChecker::visit (AST::Crate &crate)
{
  check_attributes (crate.get_inner_attrs ());

  for (auto &item : crate.items)
    item->accept_vis (*this);
}

static bool
is_builtin (const AST::Attribute &attribute, BuiltinAttrDefinition &builtin)
{
  auto &segments = attribute.get_path ().get_segments ();

  // Builtin attributes always have a single segment. This avoids us creating
  // strings all over the place and performing a linear search in the builtins
  // map
  if (segments.size () != 1)
    return false;

  builtin = BuiltinAttributeMappings::get ()->lookup_builtin (
    segments.at (0).get_segment_name ());

  return !builtin.is_error ();
}

/**
 * Check that the string given to #[doc(alias = ...)] or #[doc(alias(...))] is
 * valid.
 *
 * This means no whitespace characters other than spaces and no quoting
 * characters.
 */
static void
check_doc_alias (const std::string &alias_input, const location_t locus)
{
  // FIXME: The locus here is for the whole attribute. Can we get the locus
  // of the alias input instead?
  for (auto c : alias_input)
    if ((ISSPACE (c) && c != ' ') || c == '\'' || c == '\"')
      {
	auto to_print = std::string (1, c);
	switch (c)
	  {
	  case '\n':
	    to_print = "\\n";
	    break;
	  case '\t':
	    to_print = "\\t";
	    break;
	  default:
	    break;
	  }
	rust_error_at (locus,
		       "invalid character used in %<#[doc(alias)]%> input: %qs",
		       to_print.c_str ());
      }

  if (alias_input.empty ())
    return;

  if (alias_input.front () == ' ' || alias_input.back () == ' ')
    rust_error_at (locus,
		   "%<#[doc(alias)]%> input cannot start or end with a space");
}

static void
check_doc_attribute (const AST::Attribute &attribute)
{
  if (!attribute.has_attr_input ())
    {
      rust_error_at (
	attribute.get_locus (),
	// FIXME: Improve error message here. Rustc has a very good one
	"%<#[doc]%> cannot be an empty attribute");
      return;
    }

  switch (attribute.get_attr_input ().get_attr_input_type ())
    {
    case AST::AttrInput::LITERAL:
    case AST::AttrInput::MACRO:
    case AST::AttrInput::META_ITEM:
      break;
      // FIXME: Handle them as well

      case AST::AttrInput::TOKEN_TREE: {
	// FIXME: This doesn't check for #[doc(alias(...))]
	const auto &option = static_cast<const AST::DelimTokenTree &> (
	  attribute.get_attr_input ());
	auto *meta_item = option.parse_to_meta_item ();

	for (auto &item : meta_item->get_items ())
	  {
	    if (item->is_key_value_pair ())
	      {
		auto name_value
		  = static_cast<AST::MetaNameValueStr *> (item.get ())
		      ->get_name_value_pair ();

		// FIXME: Check for other stuff than #[doc(alias = ...)]
		if (name_value.first.as_string () == "alias")
		  check_doc_alias (name_value.second, attribute.get_locus ());
	      }
	  }
	break;
      }
    }
}

static bool
is_proc_macro_type (const AST::Attribute &attribute)
{
  BuiltinAttrDefinition result;
  if (!is_builtin (attribute, result))
    return false;

  auto name = result.name;
  return name == Attrs::PROC_MACRO || name == Attrs::PROC_MACRO_DERIVE
	 || name == Attrs::PROC_MACRO_ATTRIBUTE;
}

// Emit an error when one encountered attribute is either #[proc_macro],
// #[proc_macro_attribute] or #[proc_macro_derive]
static void
check_proc_macro_non_function (const AST::AttrVec &attributes)
{
  for (auto &attr : attributes)
    {
      if (is_proc_macro_type (attr))
	rust_error_at (
	  attr.get_locus (),
	  "the %<#[%s]%> attribute may only be used on bare functions",
	  attr.get_path ().get_segments ()[0].as_string ().c_str ());
    }
}

// Emit an error when one attribute is either proc_macro, proc_macro_attribute
// or proc_macro_derive
static void
check_proc_macro_non_root (AST::AttrVec attributes, location_t loc)
{
  for (auto &attr : attributes)
    {
      if (is_proc_macro_type (attr))
	{
	  rust_error_at (
	    loc,
	    "functions tagged with %<#[%s]%> must currently "
	    "reside in the root of the crate",
	    attr.get_path ().get_segments ().at (0).as_string ().c_str ());
	}
    }
}

void
AttributeChecker::check_attribute (const AST::Attribute &attribute)
{
  BuiltinAttrDefinition result;

  // This checker does not check non-builtin attributes
  if (!is_builtin (attribute, result))
    return;

  // TODO: Add checks here for each builtin attribute
  // TODO: Have an enum of builtins as well, switching on strings is annoying
  // and costly
  if (result.name == Attrs::DOC)
    check_doc_attribute (attribute);
}

void
AttributeChecker::check_attributes (const AST::AttrVec &attributes)
{
  for (auto &attr : attributes)
    check_attribute (attr);
}

void
AttributeChecker::visit (AST::Token &)
{}

void
AttributeChecker::visit (AST::DelimTokenTree &)
{}

void
AttributeChecker::visit (AST::AttrInputMetaItemContainer &)
{}

void
AttributeChecker::visit (AST::IdentifierExpr &)
{}

void
AttributeChecker::visit (AST::Lifetime &)
{}

void
AttributeChecker::visit (AST::LifetimeParam &)
{}

void
AttributeChecker::visit (AST::ConstGenericParam &)
{}

// rust-path.h
void
AttributeChecker::visit (AST::PathInExpression &)
{}

void
AttributeChecker::visit (AST::TypePathSegment &)
{}

void
AttributeChecker::visit (AST::TypePathSegmentGeneric &)
{}

void
AttributeChecker::visit (AST::TypePathSegmentFunction &)
{}

void
AttributeChecker::visit (AST::TypePath &)
{}

void
AttributeChecker::visit (AST::QualifiedPathInExpression &)
{}

void
AttributeChecker::visit (AST::QualifiedPathInType &)
{}

// rust-expr.h
void
AttributeChecker::visit (AST::LiteralExpr &)
{}

void
AttributeChecker::visit (AST::AttrInputLiteral &)
{}

void
AttributeChecker::visit (AST::AttrInputMacro &)
{}

void
AttributeChecker::visit (AST::MetaItemLitExpr &)
{}

void
AttributeChecker::visit (AST::MetaItemPathLit &)
{}

void
AttributeChecker::visit (AST::BorrowExpr &)
{}

void
AttributeChecker::visit (AST::DereferenceExpr &)
{}

void
AttributeChecker::visit (AST::ErrorPropagationExpr &)
{}

void
AttributeChecker::visit (AST::NegationExpr &)
{}

void
AttributeChecker::visit (AST::ArithmeticOrLogicalExpr &)
{}

void
AttributeChecker::visit (AST::ComparisonExpr &)
{}

void
AttributeChecker::visit (AST::LazyBooleanExpr &)
{}

void
AttributeChecker::visit (AST::TypeCastExpr &)
{}

void
AttributeChecker::visit (AST::AssignmentExpr &)
{}

void
AttributeChecker::visit (AST::CompoundAssignmentExpr &)
{}

void
AttributeChecker::visit (AST::GroupedExpr &)
{}

void
AttributeChecker::visit (AST::ArrayElemsValues &)
{}

void
AttributeChecker::visit (AST::ArrayElemsCopied &)
{}

void
AttributeChecker::visit (AST::ArrayExpr &)
{}

void
AttributeChecker::visit (AST::ArrayIndexExpr &)
{}

void
AttributeChecker::visit (AST::TupleExpr &)
{}

void
AttributeChecker::visit (AST::TupleIndexExpr &)
{}

void
AttributeChecker::visit (AST::StructExprStruct &)
{}

void
AttributeChecker::visit (AST::StructExprFieldIdentifier &)
{}

void
AttributeChecker::visit (AST::StructExprFieldIdentifierValue &)
{}

void
AttributeChecker::visit (AST::StructExprFieldIndexValue &)
{}

void
AttributeChecker::visit (AST::StructExprStructFields &)
{}

void
AttributeChecker::visit (AST::StructExprStructBase &)
{}

void
AttributeChecker::visit (AST::CallExpr &)
{}

void
AttributeChecker::visit (AST::MethodCallExpr &)
{}

void
AttributeChecker::visit (AST::FieldAccessExpr &)
{}

void
AttributeChecker::visit (AST::ClosureExprInner &)
{}

void
AttributeChecker::visit (AST::BlockExpr &expr)
{
  for (auto &stmt : expr.get_statements ())
    {
      if (stmt->get_stmt_kind () == AST::Stmt::Kind::Item)
	{
	  // Non owning pointer, let it go out of scope
	  auto item = static_cast<AST::Item *> (stmt.get ());
	  check_proc_macro_non_root (item->get_outer_attrs (),
				     item->get_locus ());
	}
    }
  AST::DefaultASTVisitor::visit (expr);
}

void
AttributeChecker::visit (AST::ClosureExprInnerTyped &)
{}

void
AttributeChecker::visit (AST::ContinueExpr &)
{}

void
AttributeChecker::visit (AST::BreakExpr &)
{}

void
AttributeChecker::visit (AST::RangeFromToExpr &)
{}

void
AttributeChecker::visit (AST::RangeFromExpr &)
{}

void
AttributeChecker::visit (AST::RangeToExpr &)
{}

void
AttributeChecker::visit (AST::RangeFullExpr &)
{}

void
AttributeChecker::visit (AST::RangeFromToInclExpr &)
{}

void
AttributeChecker::visit (AST::RangeToInclExpr &)
{}

void
AttributeChecker::visit (AST::ReturnExpr &)
{}

void
AttributeChecker::visit (AST::LoopExpr &)
{}

void
AttributeChecker::visit (AST::WhileLoopExpr &)
{}

void
AttributeChecker::visit (AST::WhileLetLoopExpr &)
{}

void
AttributeChecker::visit (AST::ForLoopExpr &)
{}

void
AttributeChecker::visit (AST::IfExpr &)
{}

void
AttributeChecker::visit (AST::IfExprConseqElse &)
{}

void
AttributeChecker::visit (AST::IfLetExpr &)
{}

void
AttributeChecker::visit (AST::IfLetExprConseqElse &)
{}

void
AttributeChecker::visit (AST::MatchExpr &)
{}

void
AttributeChecker::visit (AST::AwaitExpr &)
{}

void
AttributeChecker::visit (AST::AsyncBlockExpr &)
{}

// rust-item.h
void
AttributeChecker::visit (AST::TypeParam &)
{}

void
AttributeChecker::visit (AST::LifetimeWhereClauseItem &)
{}

void
AttributeChecker::visit (AST::TypeBoundWhereClauseItem &)
{}

void
AttributeChecker::visit (AST::Module &module)
{
  check_proc_macro_non_function (module.get_outer_attrs ());
  for (auto &item : module.get_items ())
    {
      check_proc_macro_non_root (item->get_outer_attrs (), item->get_locus ());
    }
  AST::DefaultASTVisitor::visit (module);
}

void
AttributeChecker::visit (AST::ExternCrate &crate)
{
  check_proc_macro_non_function (crate.get_outer_attrs ());
}

void
AttributeChecker::visit (AST::UseTreeGlob &)
{}

void
AttributeChecker::visit (AST::UseTreeList &)
{}

void
AttributeChecker::visit (AST::UseTreeRebind &)
{}

void
AttributeChecker::visit (AST::UseDeclaration &declaration)
{
  check_proc_macro_non_function (declaration.get_outer_attrs ());
}

static void
check_no_mangle_function (const AST::Attribute &attribute,
			  const AST::Function &fun)
{
  if (attribute.has_attr_input ())
    {
      rust_error_at (attribute.get_locus (), ErrorCode::E0754,
		     "malformed %<no_mangle%> attribute input");
      rust_inform (attribute.get_locus (),
		   "must be of the form: %<#[no_mangle]%>");
    }
  if (!is_ascii_only (fun.get_function_name ().as_string ()))
    rust_error_at (fun.get_function_name ().get_locus (),
		   "the %<#[no_mangle]%> attribute requires ASCII identifier");
}

void
AttributeChecker::visit (AST::Function &fun)
{
  auto check_crate_type = [] (const char *name, AST::Attribute &attribute) {
    if (!Session::get_instance ().options.is_proc_macro ())
      rust_error_at (attribute.get_locus (),
		     "the %<#[%s]%> attribute is only usable with crates of "
		     "the %<proc-macro%> crate type",
		     name);
  };

  BuiltinAttrDefinition result;
  for (auto &attribute : fun.get_outer_attrs ())
    {
      if (!is_builtin (attribute, result))
	return;

      auto name = result.name.c_str ();

      if (result.name == Attrs::PROC_MACRO_DERIVE)
	{
	  if (!attribute.has_attr_input ())
	    {
	      rust_error_at (attribute.get_locus (),
			     "malformed %qs attribute input", name);
	      rust_inform (
		attribute.get_locus (),
		"must be of the form: %<#[proc_macro_derive(TraitName, "
		"/*opt*/ attributes(name1, name2, ...))]%>");
	    }
	  check_crate_type (name, attribute);
	}
      else if (result.name == Attrs::PROC_MACRO
	       || result.name == Attrs::PROC_MACRO_ATTRIBUTE)
	{
	  check_crate_type (name, attribute);
	}
      else if (result.name == "no_mangle")
	check_no_mangle_function (attribute, fun);
    }
  if (fun.has_body ())
    fun.get_definition ().value ()->accept_vis (*this);
}

void
AttributeChecker::visit (AST::TypeAlias &alias)
{
  check_proc_macro_non_function (alias.get_outer_attrs ());
}

void
AttributeChecker::visit (AST::StructStruct &struct_item)
{
  check_attributes (struct_item.get_outer_attrs ());
  check_proc_macro_non_function (struct_item.get_outer_attrs ());
}

void
AttributeChecker::visit (AST::TupleStruct &tuplestruct)
{
  check_proc_macro_non_function (tuplestruct.get_outer_attrs ());
}

void
AttributeChecker::visit (AST::EnumItem &)
{}

void
AttributeChecker::visit (AST::EnumItemTuple &)
{}

void
AttributeChecker::visit (AST::EnumItemStruct &)
{}

void
AttributeChecker::visit (AST::EnumItemDiscriminant &)
{}

void
AttributeChecker::visit (AST::Enum &enumeration)
{
  check_proc_macro_non_function (enumeration.get_outer_attrs ());
}

void
AttributeChecker::visit (AST::Union &u)
{
  check_proc_macro_non_function (u.get_outer_attrs ());
}

void
AttributeChecker::visit (AST::ConstantItem &item)
{
  check_proc_macro_non_function (item.get_outer_attrs ());
}

void
AttributeChecker::visit (AST::StaticItem &item)
{
  check_proc_macro_non_function (item.get_outer_attrs ());
}

void
AttributeChecker::visit (AST::TraitItemConst &)
{}

void
AttributeChecker::visit (AST::TraitItemType &)
{}

void
AttributeChecker::visit (AST::Trait &trait)
{
  check_proc_macro_non_function (trait.get_outer_attrs ());
}

void
AttributeChecker::visit (AST::InherentImpl &impl)
{
  check_proc_macro_non_function (impl.get_outer_attrs ());
  AST::DefaultASTVisitor::visit (impl);
}

void
AttributeChecker::visit (AST::TraitImpl &impl)
{
  check_proc_macro_non_function (impl.get_outer_attrs ());
  AST::DefaultASTVisitor::visit (impl);
}

void
AttributeChecker::visit (AST::ExternalTypeItem &)
{}

void
AttributeChecker::visit (AST::ExternalStaticItem &)
{}

void
AttributeChecker::visit (AST::ExternBlock &block)
{
  check_proc_macro_non_function (block.get_outer_attrs ());
}

// rust-macro.h
void
AttributeChecker::visit (AST::MacroMatchFragment &)
{}

void
AttributeChecker::visit (AST::MacroMatchRepetition &)
{}

void
AttributeChecker::visit (AST::MacroMatcher &)
{}

void
AttributeChecker::visit (AST::MacroRulesDefinition &)
{}

void
AttributeChecker::visit (AST::MacroInvocation &)
{}

void
AttributeChecker::visit (AST::MetaItemPath &)
{}

void
AttributeChecker::visit (AST::MetaItemSeq &)
{}

void
AttributeChecker::visit (AST::MetaWord &)
{}

void
AttributeChecker::visit (AST::MetaNameValueStr &)
{}

void
AttributeChecker::visit (AST::MetaListPaths &)
{}

void
AttributeChecker::visit (AST::MetaListNameValueStr &)
{}

// rust-pattern.h
void
AttributeChecker::visit (AST::LiteralPattern &)
{}

void
AttributeChecker::visit (AST::IdentifierPattern &)
{}

void
AttributeChecker::visit (AST::WildcardPattern &)
{}

void
AttributeChecker::visit (AST::RestPattern &)
{}

// void AttributeChecker::visit(RangePatternBound& ){}

void
AttributeChecker::visit (AST::RangePatternBoundLiteral &)
{}

void
AttributeChecker::visit (AST::RangePatternBoundPath &)
{}

void
AttributeChecker::visit (AST::RangePatternBoundQualPath &)
{}

void
AttributeChecker::visit (AST::RangePattern &)
{}

void
AttributeChecker::visit (AST::ReferencePattern &)
{}

// void AttributeChecker::visit(StructPatternField& ){}

void
AttributeChecker::visit (AST::StructPatternFieldTuplePat &)
{}

void
AttributeChecker::visit (AST::StructPatternFieldIdentPat &)
{}

void
AttributeChecker::visit (AST::StructPatternFieldIdent &)
{}

void
AttributeChecker::visit (AST::StructPattern &)
{}

// void AttributeChecker::visit(TupleStructItems& ){}

void
AttributeChecker::visit (AST::TupleStructItemsNoRange &)
{}

void
AttributeChecker::visit (AST::TupleStructItemsRange &)
{}

void
AttributeChecker::visit (AST::TupleStructPattern &)
{}

// void AttributeChecker::visit(TuplePatternItems& ){}

void
AttributeChecker::visit (AST::TuplePatternItemsMultiple &)
{}

void
AttributeChecker::visit (AST::TuplePatternItemsRanged &)
{}

void
AttributeChecker::visit (AST::TuplePattern &)
{}

void
AttributeChecker::visit (AST::GroupedPattern &)
{}

void
AttributeChecker::visit (AST::SlicePattern &)
{}

void
AttributeChecker::visit (AST::AltPattern &)
{}

// rust-stmt.h
void
AttributeChecker::visit (AST::EmptyStmt &)
{}

void
AttributeChecker::visit (AST::LetStmt &)
{}

void
AttributeChecker::visit (AST::ExprStmt &)
{}

// rust-type.h
void
AttributeChecker::visit (AST::TraitBound &)
{}

void
AttributeChecker::visit (AST::ImplTraitType &)
{}

void
AttributeChecker::visit (AST::TraitObjectType &)
{}

void
AttributeChecker::visit (AST::ParenthesisedType &)
{}

void
AttributeChecker::visit (AST::ImplTraitTypeOneBound &)
{}

void
AttributeChecker::visit (AST::TraitObjectTypeOneBound &)
{}

void
AttributeChecker::visit (AST::TupleType &)
{}

void
AttributeChecker::visit (AST::NeverType &)
{}

void
AttributeChecker::visit (AST::RawPointerType &)
{}

void
AttributeChecker::visit (AST::ReferenceType &)
{}

void
AttributeChecker::visit (AST::ArrayType &)
{}

void
AttributeChecker::visit (AST::SliceType &)
{}

void
AttributeChecker::visit (AST::InferredType &)
{}

void
AttributeChecker::visit (AST::BareFunctionType &)
{}

void
AttributeChecker::visit (AST::SelfParam &)
{}

void
AttributeChecker::visit (AST::VariadicParam &)
{}

void
AttributeChecker::visit (AST::FunctionParam &)
{}

} // namespace Analysis
} // namespace Rust