1 files changed, 115 insertions, 20 deletions

diff --git a/gcc/logical-location.h b/gcc/logical-location.h
index 000335c..dba9dc4 100644
--- a/gcc/logical-location.h
+++ b/gcc/logical-location.h
@@ -33,6 +33,7 @@ enum logical_location_kind
 {
   LOGICAL_LOCATION_KIND_UNKNOWN,
 
+  /* Kinds within executable code.  */
   LOGICAL_LOCATION_KIND_FUNCTION,
   LOGICAL_LOCATION_KIND_MEMBER,
   LOGICAL_LOCATION_KIND_MODULE,
@@ -40,41 +41,135 @@ enum logical_location_kind
   LOGICAL_LOCATION_KIND_TYPE,
   LOGICAL_LOCATION_KIND_RETURN_TYPE,
   LOGICAL_LOCATION_KIND_PARAMETER,
-  LOGICAL_LOCATION_KIND_VARIABLE
+  LOGICAL_LOCATION_KIND_VARIABLE,
+
+  /* Kinds within XML or HTML documents.  */
+  LOGICAL_LOCATION_KIND_ELEMENT,
+  LOGICAL_LOCATION_KIND_ATTRIBUTE,
+  LOGICAL_LOCATION_KIND_TEXT,
+  LOGICAL_LOCATION_KIND_COMMENT,
+  LOGICAL_LOCATION_KIND_PROCESSING_INSTRUCTION,
+  LOGICAL_LOCATION_KIND_DTD,
+  LOGICAL_LOCATION_KIND_DECLARATION,
+
+  /* Kinds within JSON documents.  */
+  LOGICAL_LOCATION_KIND_OBJECT,
+  LOGICAL_LOCATION_KIND_ARRAY,
+  LOGICAL_LOCATION_KIND_PROPERTY,
+  LOGICAL_LOCATION_KIND_VALUE
 };
 
-/* Abstract base class for passing around logical locations in the
+/* We want to efficiently support passing around logical locations in the
    diagnostics subsystem, such as:
    - "within function 'foo'", or
-   - "within method 'bar'",
-   but *without* requiring knowledge of trees
-   (see tree-logical-location.h for concrete subclasses relating to trees,
-   and selftest-logical-location.h for a concrete subclass for selftests).  */
+   - "within method 'bar'"
 
-class logical_location
+   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_location, which is
+   a wrapper around a (const void *), and logical_location_manager which
+   is provided by the client and has vfunc hooks for interpreting
+   logical_location instances.
+
+   Every logical_location is associated with a logical_location_manager and
+   only has meaning in relation to that manager.
+
+   A "nullptr" within a logical_location means "no logical location".
+
+   See tree-logical-location.h for concrete subclasses relating to trees,
+   where the pointer is a const_tree.
+
+   See selftest-logical-location.h for a concrete subclass for selftests.  */
+
+/* Abstract base class for giving meaning to logical_location values.
+   Typically there will just be one client-provided instance, of a
+   client-specific subclass.  */
+
+class logical_location_manager
 {
 public:
-  virtual ~logical_location () {}
-
-  /* Get a string (or NULL) suitable for use by the SARIF logicalLocation
+  /* 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".  */
+  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;
+  };
+
+  virtual ~logical_location_manager () {}
+
+  /* vfuncs for interpreting logical_location values.  */
+
+  /* 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 () const = 0;
+  virtual const char *get_short_name (key k) const = 0;
 
-  /* Get a string (or NULL) suitable for use by the SARIF logicalLocation
+  /* 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 () const = 0;
+  virtual const char *get_name_with_scope (key k) const = 0;
 
-  /* Get a string (or NULL) suitable for use by the SARIF logicalLocation
+  /* 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 () const = 0;
+  virtual const char *get_internal_name (key k) const = 0;
+
+  /* Get what kind of SARIF logicalLocation K is (if any).  */
+  virtual enum logical_location_kind get_kind (key k) const = 0;
 
-  /* Get what kind of SARIF logicalLocation this is (if any).  */
-  virtual enum logical_location_kind get_kind () 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 a string for this location in a form suitable for path output.  */
-  virtual label_text get_name_for_path_output () const = 0;
+  /* Get the parent logical_logical of K, if any, or nullptr.  */
+  virtual key get_parent (key k) const = 0;
 
-  bool function_p () const;
+  bool function_p (key k) const;
 };
 
+/* A logical location is a key for a given logical_location_manager.
+
+   Note that there is no integration with GCC's garbage collector and thus
+   logical_location instances can't be long-lived.  */
+
+typedef logical_location_manager::key logical_location;
+
 #endif /* GCC_LOGICAL_LOCATION_H.  */