gcc/diagnostics/logical-locations.h

/* Logical location support, without knowledge of "tree".
   Copyright (C) 2022-2025 Free Software Foundation, Inc.
   Contributed by David Malcolm <dmalcolm@redhat.com>.

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/>.  */

#ifndef GCC_DIAGNOSTICS_LOGICAL_LOCATIONS_H
#define GCC_DIAGNOSTICS_LOGICAL_LOCATIONS_H

#include "label-text.h"

namespace diagnostics {
namespace logical_locations {

/* An enum for discriminating between different kinds of logical location
   for a diagnostic.

   Roughly corresponds to logicalLocation's "kind" property in SARIF v2.1.0
   (section 3.33.7).  */

enum class kind
{
  unknown,

  /* Kinds within executable code.  */
  function,
  member,
  module_,
  namespace_,
  type,
  return_type,
  parameter,
  variable,

  /* Kinds within XML or HTML documents.  */
  element,
  attribute,
  text,
  comment,
  processing_instruction,
  dtd,
  declaration,

  /* Kinds within JSON documents.  */
  object,
  array,
  property,
  value
};

/* We want to efficiently support passing around logical locations in the
   diagnostics subsystem, such as:
   - "within function 'foo'", or
   - "within method 'bar'"

   However we want to do this *without* requiring knowledge of trees (or of
   libgdiagnostics internals), and without requiring heap allocation of an
   interface class when emitting a diagnostic.

   To do this, we split the implementation into logical_locations::key, which is
   a wrapper around a (const void *), and logical_locations::manager which
   is provided by the client and has vfunc hooks for interpreting
   key instances.

   Every logical_locations::key is associated with a logical_locations::manager
   and only has meaning in relation to that manager.

   A "nullptr" within a key means "no logical location".

   See tree-logical-location.h for concrete subclasses relating to trees,
   where the pointer is a const_tree.

   See diagnostics/selftest-logical-locations.h for a concrete subclass for
   selftests.  */

/* Extrinsic state for identifying a specific logical location.
   This will be our logical location type.
   This only makes sense with respect to a specific manager.
   e.g. for a tree-based one it's a wrapper around "tree".

   "nullptr" means "no logical location".

   Note that there is no integration with GCC's garbage collector and thus
   keys can't be long-lived.  */

class key
{
public:
  key () : m_ptr (nullptr) {}

  static key from_ptr (const void *ptr)
  {
    return key (ptr);
  }

  operator bool () const
  {
    return m_ptr != nullptr;
  }

  template <typename T>
  T cast_to () const { return static_cast<T> (m_ptr); }

  bool
  operator== (const key &other) const
  {
    return m_ptr == other.m_ptr;
  }

  bool
  operator!= (const key &other) const
  {
    return m_ptr != other.m_ptr;
  }

  bool
  operator< (const key &other) const
  {
    return m_ptr < other.m_ptr;
  }

private:
  explicit key (const void *ptr) : m_ptr (ptr) {}

  const void *m_ptr;
};

/* Abstract base class for giving meaning to keys.
   Typically there will just be one client-provided instance, of a
   client-specific subclass.  */

class manager
{
public:
  virtual ~manager () {}

  /* vfuncs for interpreting keys.  */

  /* Get a string (or NULL) for K suitable for use by the SARIF logicalLocation
     "name" property (SARIF v2.1.0 section 3.33.4).  */
  virtual const char *get_short_name (key k) const = 0;

  /* Get a string (or NULL) for K suitable for use by the SARIF logicalLocation
     "fullyQualifiedName" property (SARIF v2.1.0 section 3.33.5).  */
  virtual const char *get_name_with_scope (key k) const = 0;

  /* Get a string (or NULL) for K suitable for use by the SARIF logicalLocation
     "decoratedName" property (SARIF v2.1.0 section 3.33.6).  */
  virtual const char *get_internal_name (key k) const = 0;

  /* Get what kind of SARIF logicalLocation K is (if any).  */
  virtual enum kind get_kind (key k) const = 0;

  /* Get a string for location K in a form suitable for path output.  */
  virtual label_text get_name_for_path_output (key k) const = 0;

  /* Get the parent logical_logical of K, if any, or nullptr.  */
  virtual key get_parent (key k) const = 0;

  bool function_p (key k) const;
};

} // namespace diagnostics::logical_locations
} // namespace diagnostics

#endif /* GCC_DIAGNOSTICS_LOGICAL_LOCATIONS_H.  */