Linemap infrastructure for virtual locations

This is the first instalment of a set which goal is to track locations
of tokens across macro expansions.  Tom Tromey did the original work
and attached the patch to PR preprocessor/7263.  This opus is a
derivative of that original work.

This patch modifies the linemap module of libcpp to add virtual
locations support.

A virtual location is a mapped location that can resolve to several
different physical locations.  It can always resolve to the spelling
location of a token.  For tokens resulting from macro expansion it can
resolve to:
  - either the location of the expansion point of the macro.
  - or the location of the token in the definition of the
  macro
  - or, if the token is an argument of a function-like macro,
  the location of the use of the matching macro parameter in
  the definition of the macro

The patch creates a new type of line map called a macro map.  For every
single macro expansion, there is a macro map that generates a virtual
location for every single resulting token of the expansion.

The good old type of line map we all know is now called an ordinary
map.  That one still encodes spelling locations as it has always had.

As a result linemap_lookup as been extended to return a macro map when
given a virtual location resulting from a macro expansion.  The layout
of structs line_map has changed to support this new type of map.  So
did the layout of struct line_maps.  Accessor macros have been
introduced to avoid messing with the implementation details of these
datastructures directly.  This helped already as we have been testing
different ways of arranging these datastructure.  Having to constantly
adjust client code that is too tied with the internals of line_map and
line_maps would have been even more painful.

Of course, many new public functions have been added to the linemap
module to handle the resolution of virtual locations.

This patch introduces the infrastructure but no part of the compiler
uses virtual locations yet.

However the client code of the linemap data structures has been
adjusted as per the changes.  E.g, it's not anymore reliable for a
client code to manipulate struct line_map directly if it just wants to
deal with spelling locations, because struct line_map can now
represent a macro map as well.  In that case, it's better to use the
convenient API to resolve the initial (possibly virtual) location to a
spelling location (or to an ordinary map) and use that.

This is the reason why the patch adjusts the Java, Ada and Fortran
front ends.

Also, note that virtual locations are not supposed to be ordered for
relations '<' and '>' anymore.  To test if a virtual location appears
"before" another one, one has to use a new operator exposed by the
line map interface.  The patch updates the only spot (in the
diagnostics module) I have found that was making the assumption that
locations were ordered for these relations.  This is the only change
that introduces a use of the new line map API in this patch, so I am
adding a regression test for it only.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@180081 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 546 insertions, 39 deletions

diff --git a/libcpp/include/line-map.h b/libcpp/include/line-map.h
index 3c84035e95f..d3c52b241bd 100644
--- a/libcpp/include/line-map.h
+++ b/libcpp/include/line-map.h
@@ -27,13 +27,22 @@ along with this program; see the file COPYING3.  If not see
 #define GTY(x) /* nothing */
 #endif
 
-/* Reason for adding a line change with add_line_map ().  LC_ENTER is
+/* Reason for creating a new line map with linemap_add.  LC_ENTER is
    when including a new file, e.g. a #include directive in C.
    LC_LEAVE is when reaching a file's end.  LC_RENAME is when a file
    name or line number changes for neither of the above reasons
    (e.g. a #line directive in C); LC_RENAME_VERBATIM is like LC_RENAME
-   but a filename of "" is not specially interpreted as standard input.  */
-enum lc_reason {LC_ENTER = 0, LC_LEAVE, LC_RENAME, LC_RENAME_VERBATIM};
+   but a filename of "" is not specially interpreted as standard
+   input. LC_ENTER_MACRO is when a macro expansion is about to start.  */
+enum lc_reason
+{
+  LC_ENTER = 0,
+  LC_LEAVE,
+  LC_RENAME,
+  LC_RENAME_VERBATIM,
+  LC_ENTER_MACRO
+  /* FIXME: add support for stringize and paste.  */
+};
 
 /* The type of line numbers.  */
 typedef unsigned int linenum_type;
@@ -44,37 +53,214 @@ typedef unsigned int source_location;
 /* Memory allocation function typedef.  Works like xrealloc.  */
 typedef void *(*line_map_realloc) (void *, size_t);
 
-/* Physical source file TO_FILE at line TO_LINE at column 0 is represented
+/* An ordinary line map encodes physical source locations. Those
+   physical source locations are called "spelling locations".
+   
+   Physical source file TO_FILE at line TO_LINE at column 0 is represented
    by the logical START_LOCATION.  TO_LINE+L at column C is represented by
    START_LOCATION+(L*(1<<column_bits))+C, as long as C<(1<<column_bits),
    and the result_location is less than the next line_map's start_location.
    (The top line is line 1 and the leftmost column is column 1; line/column 0
    means "entire file/line" or "unknown line/column" or "not applicable".)
-   INCLUDED_FROM is an index into the set that gives the line mapping
-   at whose end the current one was included.  File(s) at the bottom
-   of the include stack have this set to -1.  REASON is the reason for
-   creation of this line map, SYSP is one for a system header, two for
-   a C system header file that therefore needs to be extern "C"
-   protected in C++, and zero otherwise.  */
-struct GTY(()) line_map {
+
+   The highest possible source location is MAX_SOURCE_LOCATION.  */
+struct GTY(()) line_map_ordinary {
   const char *to_file;
   linenum_type to_line;
-  source_location start_location;
+
+  /* An index into the set that gives the line mapping at whose end
+     the current one was included.  File(s) at the bottom of the
+     include stack have this set to -1.  */
   int included_from;
-  ENUM_BITFIELD (lc_reason) reason : CHAR_BIT;
-  /* The sysp field isn't really needed now that it's in cpp_buffer.  */
+
+  /* SYSP is one for a system header, two for a C system header file
+     that therefore needs to be extern "C" protected in C++, and zero
+     otherwise.  This field isn't really needed now that it's in
+     cpp_buffer.  */
   unsigned char sysp;
+
   /* Number of the low-order source_location bits used for a column number.  */
   unsigned int column_bits : 8;
 };
 
-/* A set of chronological line_map structures.  */
-struct GTY(()) line_maps {
+/* This is the highest possible source location encoded within an
+   ordinary or macro map.  */
+#define MAX_SOURCE_LOCATION 0xFFFFFFFF
+
+struct cpp_hashnode;
+
+/* A macro line map encodes location of tokens coming from a macro
+   expansion.
+   
+   Please note that this struct line_map_macro is a field of struct
+   line_map below, go read the comments of struct line_map below and
+   then come back here.
+   
+   The offset from START_LOCATION is used to index into
+   MACRO_LOCATIONS; this holds the original location of the token.  */
+struct GTY(()) line_map_macro {
+  /* The cpp macro which expansion gave birth to this macro map.  */
+  struct cpp_hashnode * GTY ((nested_ptr (union tree_node,
+				   "%h ? CPP_HASHNODE (GCC_IDENT_TO_HT_IDENT (%h)) : NULL",
+				   "%h ? HT_IDENT_TO_GCC_IDENT (HT_NODE (%h)) : NULL")))
+    macro;
+
+  /* The number of tokens inside the replacement-list of MACRO.  */
+  unsigned int n_tokens;
+
+  /* This array of location is actually an array of pairs of
+     locations. The elements inside it thus look like:
+
+           x0,y0, x1,y1, x2,y2, ...., xn,yn.
+
+     where n == n_tokens;
+
+     Remember that these xI,yI are collected when libcpp is about to
+     expand a given macro.
+
+     yI is the location in the macro definition, either of the token
+     itself or of a macro parameter that it replaces.
+
+     Imagine this:
+
+	#define PLUS(A, B) A + B  <--- #1
+
+	int a = PLUS (1,2); <--- #2
+
+     There is a macro map for the expansion of PLUS in #2.  PLUS is
+     expanded into its expansion-list.  The expansion-list is the
+     replacement-list of PLUS where the macro parameters are replaced
+     with their arguments.  So the replacement-list of PLUS is made of
+     the tokens:
+
+        A, +, B
+
+     and the expansion-list is made of the tokens:
+
+        1, +, 2
+
+     Let's consider the case of token "+".  Its y1 [yI for I == 1] is
+     its spelling location in #1.
+
+     y0 (thus for token "1") is the spelling location of A in #1.
+
+     And y2 (of token "2") is the spelling location of B in #1.
+
+     When the token is /not/ an argument for a macro, xI is the same
+     location as yI.  Otherwise, xI is the location of the token
+     outside this macro expansion.  If this macro was expanded from
+     another macro expansion, xI is a virtual location representing
+     the token in that macro expansion; otherwise, it is the spelling
+     location of the token.
+
+     Note that a virtual location is a location returned by
+     linemap_add_macro_token.  It encodes the relevant locations (x,y
+     pairs) of that token accross the macro expansions from which it
+     (the token) might come from.
+
+     In the example above x1 (for token "+") is going to be the same
+     as y1.  x0 is the spelling location for the argument token "1",
+     and x2 is the spelling location for the argument token "2".  */
+  source_location * GTY((length ("2 * %h.n_tokens"))) macro_locations;
+
+  /* This is the location of the expansion point of the current macro
+     map.  It's the location of the macro name.  That location is held
+     by the map that was current right before the current one. It
+     could have been either a macro or an ordinary map, depending on
+     if we are in a nested expansion context not.  */
+  source_location expansion;
+};
+
+/* A line_map encodes a sequence of locations.
+   There are two kinds of maps. Ordinary maps and macro expansion
+   maps, a.k.a macro maps.
+
+   A macro map encodes source locations of tokens that are part of a
+   macro replacement-list, at a macro expansion point. E.g, in:
+
+            #define PLUS(A,B) A + B
+
+   No macro map is going to be created there, because we are not at a
+   macro expansion point. We are at a macro /definition/ point. So the
+   locations of the tokens of the macro replacement-list (i.e, A + B)
+   will be locations in an ordinary map, not a macro map.
+
+   On the other hand, if we later do:
+
+        int a = PLUS (1,2);
+
+   The invocation of PLUS here is a macro expansion. So we are at a
+   macro expansion point. The preprocessor expands PLUS (1,2) and
+   replaces it with the tokens of its replacement-list: 1 + 2. A macro
+   map is going to be created to hold (or rather to map, haha ...) the
+   locations of the tokens 1, + and 2. The macro map also records the
+   location of the expansion point of PLUS. That location is mapped in
+   the map that is active right before the location of the invocation
+   of PLUS.  */
+struct GTY(()) line_map {
+  source_location start_location;
+
+  /* The reason for creation of this line map.  */
+  ENUM_BITFIELD (lc_reason) reason : CHAR_BIT;
+
+  union map_u {
+    struct line_map_ordinary GTY((tag ("0"))) ordinary;
+    struct line_map_macro GTY((tag ("1"))) macro;
+  } GTY((desc ("%1.reason == LC_ENTER_MACRO"))) d;
+};
+
+#define MAP_START_LOCATION(MAP) (MAP)->start_location
+
+#define ORDINARY_MAP_FILE_NAME(MAP) \
+  linemap_check_ordinary (MAP)->d.ordinary.to_file
+
+#define ORDINARY_MAP_STARTING_LINE_NUMBER(MAP) \
+  linemap_check_ordinary (MAP)->d.ordinary.to_line
+
+#define ORDINARY_MAP_INCLUDER_FILE_INDEX(MAP) \
+  linemap_check_ordinary (MAP)->d.ordinary.included_from
+
+#define ORDINARY_MAP_IN_SYSTEM_HEADER_P(MAP) \
+  linemap_check_ordinary (MAP)->d.ordinary.sysp
+
+#define ORDINARY_MAP_NUMBER_OF_COLUMN_BITS(MAP) \
+  linemap_check_ordinary (MAP)->d.ordinary.column_bits
+
+#define MACRO_MAP_MACRO(MAP) (MAP)->d.macro.macro
+
+#define MACRO_MAP_NUM_MACRO_TOKENS(MAP) (MAP)->d.macro.n_tokens
+
+#define MACRO_MAP_LOCATIONS(MAP) (MAP)->d.macro.macro_locations
+
+#define MACRO_MAP_EXPANSION_POINT_LOCATION(MAP) (MAP)->d.macro.expansion
+
+/* The abstraction of a set of location maps. There can be several
+   types of location maps. This abstraction contains the attributes
+   that are independent from the type of the map.  */
+struct GTY(()) maps_info {
+  /* This array contains the different line maps.
+     A line map is created for the following events:
+       - when a new preprocessing unit start. 
+       - when a preprocessing unit ends.
+       - when a macro expansion occurs.  */
   struct line_map * GTY ((length ("%h.used"))) maps;
+
+  /* The total number of allocated maps.  */
   unsigned int allocated;
+
+  /* The number of elements used in maps. This number is smaller
+     or equal to ALLOCATED.  */
   unsigned int used;
 
   unsigned int cache;
+};
+
+/* A set of chronological line_map structures.  */
+struct GTY(()) line_maps {
+  
+  struct maps_info info_ordinary;
+
+  struct maps_info info_macro;
 
   /* Depth of the include stack, including the current file.  */
   unsigned int depth;
@@ -97,12 +283,126 @@ struct GTY(()) line_maps {
   line_map_realloc reallocator;
 };
 
+/* Returns the pointer to the memory region where information about
+   maps are stored in the line table SET. MACRO_MAP_P is a flag
+   telling if we want macro or ordinary maps.  */
+#define LINEMAPS_MAP_INFO(SET, MACRO_MAP_P)				\
+  ((MACRO_MAP_P)							\
+   ? &((SET)->info_macro)						\
+   : &((SET)->info_ordinary))
+
+/* Returns the pointer to the memory region where maps are stored in
+   the line table SET. MAP_KIND shall be TRUE if we are interested in
+   macro maps false otherwise.  */
+#define LINEMAPS_MAPS(SET, MAP_KIND) \
+  (LINEMAPS_MAP_INFO (SET, MAP_KIND))->maps
+
+/* Returns the number of allocated maps so far. MAP_KIND shall be TRUE
+   if we are interested in macro maps, FALSE otherwise.  */
+#define LINEMAPS_ALLOCATED(SET, MAP_KIND) \
+  (LINEMAPS_MAP_INFO (SET, MAP_KIND))->allocated
+
+/* Returns the number of used maps so far. MAP_KIND shall be TRUE if
+   we are interested in macro maps, FALSE otherwise.*/
+#define LINEMAPS_USED(SET, MAP_KIND) \
+  (LINEMAPS_MAP_INFO (SET, MAP_KIND))->used
+
+/* Returns the index of the last map that was looked up with
+   linemap_lookup. MAP_KIND shall be TRUE if we are interested in
+   macro maps, FALSE otherwise.  */
+#define LINEMAPS_CACHE(SET, MAP_KIND) \
+  (LINEMAPS_MAP_INFO (SET, MAP_KIND))->cache
+
+/* Return the map at a given index.  */
+#define LINEMAPS_MAP_AT(SET, MAP_KIND, INDEX)	\
+  (&((LINEMAPS_MAPS (SET, MAP_KIND))[(INDEX)]))
+
+/* Returns the last map used in the line table SET. MAP_KIND
+   shall be TRUE if we are interested in macro maps, FALSE
+   otherwise.*/
+#define LINEMAPS_LAST_MAP(SET, MAP_KIND) \
+  LINEMAPS_MAP_AT (SET, MAP_KIND, (LINEMAPS_USED (SET, MAP_KIND) - 1))
+
+/* Returns the last map that was allocated in the line table SET.
+   MAP_KIND shall be TRUE if we are interested in macro maps, FALSE
+   otherwise.*/
+#define LINEMAPS_LAST_ALLOCATED_MAP(SET, MAP_KIND) \
+  LINEMAPS_MAP_AT (SET, MAP_KIND, LINEMAPS_ALLOCATED (SET, MAP_KIND) - 1)
+
+/* Returns a pointer to the memory region where ordinary maps are
+   allocated in the line table SET.  */
+#define LINEMAPS_ORDINARY_MAPS(SET) \
+  LINEMAPS_MAPS (SET, false)
+
+/* Returns the INDEXth ordinary map.  */
+#define LINEMAPS_ORDINARY_MAP_AT(SET, INDEX)	\
+  LINEMAPS_MAP_AT (SET, false, INDEX)
+
+/* Return the number of ordinary maps allocated in the line table
+   SET.  */
+#define LINEMAPS_ORDINARY_ALLOCATED(SET) \
+  LINEMAPS_ALLOCATED(SET, false)
+
+/* Return the number of ordinary maps used in the line table SET.  */
+#define LINEMAPS_ORDINARY_USED(SET) \
+  LINEMAPS_USED(SET, false)
+
+/* Return the index of the last ordinary map that was looked up with
+   linemap_lookup.  */
+#define LINEMAPS_ORDINARY_CACHE(SET) \
+  LINEMAPS_CACHE(SET, false)
+
+/* Returns a pointer to the last ordinary map used in the line table
+   SET.  */
+#define LINEMAPS_LAST_ORDINARY_MAP(SET) \
+  LINEMAPS_LAST_MAP(SET, false)
+
+/* Returns a pointer to the last ordinary map allocated the line table
+   SET.  */
+#define LINEMAPS_LAST_ALLOCATED_ORDINARY_MAP(SET) \
+  LINEMAPS_LAST_ALLOCATED_MAP(SET, false)
+
+/* Returns a pointer to the begining of the region where macro maps
+   are allcoated.  */
+#define LINEMAPS_MACRO_MAPS(SET) \
+  LINEMAPS_MAPS(SET, true)
+
+/* Returns the INDEXth macro map.  */
+#define LINEMAPS_MACRO_MAP_AT(SET, INDEX)	\
+  LINEMAPS_MAP_AT (SET, true, INDEX)
+
+/* Returns the number of macro maps that were allocated in the line
+   table SET.  */
+#define LINEMAPS_MACRO_ALLOCATED(SET) \
+  LINEMAPS_ALLOCATED(SET, true)
+
+/* Returns the number of macro maps used in the line table SET.  */
+#define LINEMAPS_MACRO_USED(SET) \
+  LINEMAPS_USED(SET, true)
+
+/* Returns the index of the last macro map looked up with
+   linemap_lookup.  */
+#define LINEMAPS_MACRO_CACHE(SET) \
+  LINEMAPS_CACHE(SET, true)
+
+/* Returns the lowest location [of a token resulting from macro
+   expansion] encoded in this line table.  */
+#define LINEMAPS_MACRO_LOWEST_LOCATION(SET)			\
+  (LINEMAPS_MACRO_USED (set)					\
+   ? MAP_START_LOCATION (LINEMAPS_LAST_MACRO_MAP (set))		\
+   : MAX_SOURCE_LOCATION)
+
+/* Returns the last macro map used in the line table SET.  */
+#define LINEMAPS_LAST_MACRO_MAP(SET) \
+  LINEMAPS_LAST_MAP (SET, true)
+
+/* Returns the last macro map allocated in the line table SET.  */
+#define LINEMAPS_LAST_ALLOCATED_MACRO_MAP(SET) \
+  LINEMAPS_LAST_ALLOCATED_MAP (SET, true)
+
 /* Initialize a line map set.  */
 extern void linemap_init (struct line_maps *);
 
-/* Free a line map set.  */
-extern void linemap_free (struct line_maps *);
-
 /* Check for and warn about line_maps entered but not exited.  */
 
 extern void linemap_check_files_exited (struct line_maps *);
@@ -117,10 +417,12 @@ extern source_location linemap_line_start
 (struct line_maps *set, linenum_type to_line,  unsigned int max_column_hint);
 
 /* Add a mapping of logical source line to physical source file and
-   line number.
+   line number. This function creates an "ordinary map", which is a
+   map that records locations of tokens that are not part of macro
+   replacement-lists present at a macro expansion point.
 
    The text pointed to by TO_FILE must have a lifetime
-   at least as long as the final call to lookup_line ().  An empty
+   at least as long as the lifetime of SET.  An empty
    TO_FILE means standard input.  If reason is LC_LEAVE, and
    TO_FILE is NULL, then TO_FILE, TO_LINE and SYSP are given their
    natural values considering the file we are returning to.
@@ -131,41 +433,246 @@ extern const struct line_map *linemap_add
   (struct line_maps *, enum lc_reason, unsigned int sysp,
    const char *to_file, linenum_type to_line);
 
-/* Given a logical line, returns the map from which the corresponding
-   (source file, line) pair can be deduced.  */
+/* Given a logical source location, returns the map which the
+   corresponding (source file, line, column) triplet can be deduced
+   from. Since the set is built chronologically, the logical lines are
+   monotonic increasing, and so the list is sorted and we can use a
+   binary search. If no line map have been allocated yet, this
+   function returns NULL.  */
 extern const struct line_map *linemap_lookup
   (struct line_maps *, source_location);
 
+/* Returns TRUE if the line table set tracks token locations accross
+   macro expansion, FALSE otherwise.  */
+bool linemap_tracks_macro_expansion_locs_p (struct line_maps *);
+
+/* Return TRUE if MAP encodes locations coming from a macro
+   replacement-list at macro expansion point.  */
+bool linemap_macro_expansion_map_p (const struct line_map *);
+
+/* Return the name of the macro associated to MACRO_MAP.  */
+const char* linemap_map_get_macro_name (const struct line_map*);
+
+/* Return a positive value if LOCATION is the locus of a token that is
+   located in a system header, O otherwise. It returns 1 if LOCATION
+   is the locus of a token that is located in a system header, and 2
+   if LOCATION is the locus of a token located in a C system header
+   that therefore needs to be extern "C" protected in C++.
+
+   Note that this function returns 1 if LOCATION belongs to a token
+   that is part of a macro replacement-list defined in a system
+   header, but expanded in a non-system file.  */
+int linemap_location_in_system_header_p (struct line_maps *,
+					 source_location);
+
+/* Return TRUE if LOCATION is a source code location of a token coming
+   from a macro replacement-list at a macro expansion point, FALSE
+   otherwise.  */
+bool linemap_location_from_macro_expansion_p (struct line_maps *,
+					      source_location);
+
 /* source_location values from 0 to RESERVED_LOCATION_COUNT-1 will
    be reserved for libcpp user as special values, no token from libcpp
    will contain any of those locations.  */
 #define RESERVED_LOCATION_COUNT	2
 
 /* Converts a map and a source_location to source line.  */
-#define SOURCE_LINE(MAP, LOC) \
-  ((((LOC) - (MAP)->start_location) >> (MAP)->column_bits) + (MAP)->to_line)
-
-#define SOURCE_COLUMN(MAP, LOC) \
-  (((LOC) - (MAP)->start_location) & ((1 << (MAP)->column_bits) - 1))
-
-/* Returns the last source line within a map.  This is the (last) line
-   of the #include, or other directive, that caused a map change.  */
+#define SOURCE_LINE(MAP, LOC)						\
+  (((((LOC) - linemap_check_ordinary (MAP)->start_location)		\
+     >> (MAP)->d.ordinary.column_bits) + (MAP)->d.ordinary.to_line))
+
+/* Convert a map and source_location to source column number.  */
+#define SOURCE_COLUMN(MAP, LOC)						\
+  ((((LOC) - linemap_check_ordinary (MAP)->start_location)		\
+    & ((1 << (MAP)->d.ordinary.column_bits) - 1)))
+
+/* Returns the last source line number within an ordinary map.  This
+   is the (last) line of the #include, or other directive, that caused
+   a map change.  */
 #define LAST_SOURCE_LINE(MAP) \
   SOURCE_LINE (MAP, LAST_SOURCE_LINE_LOCATION (MAP))
+
+/* Return the last column number within an ordinary map.  */
 #define LAST_SOURCE_COLUMN(MAP) \
   SOURCE_COLUMN (MAP, LAST_SOURCE_LINE_LOCATION (MAP))
-#define LAST_SOURCE_LINE_LOCATION(MAP) \
-  ((((MAP)[1].start_location - 1 - (MAP)->start_location) \
-    & ~((1 << (MAP)->column_bits) - 1))			  \
-   + (MAP)->start_location)
 
-/* Returns the map a given map was included from.  */
-#define INCLUDED_FROM(SET, MAP) (&(SET)->maps[(MAP)->included_from])
+/* Return the location of the last source line within an ordinary
+   map.  */
+#define LAST_SOURCE_LINE_LOCATION(MAP)					\
+  ((((linemap_check_ordinary (MAP)[1].start_location - 1		\
+      - (MAP)->start_location)						\
+     & ~((1 << (MAP)->d.ordinary.column_bits) - 1))			\
+    + (MAP)->start_location))
+
+/* Returns the map a given map was included from, or NULL if the map
+   belongs to the main file, i.e, a file that wasn't included by
+   another one.  */
+#define INCLUDED_FROM(SET, MAP)						\
+  ((linemap_check_ordinary (MAP)->d.ordinary.included_from == -1)	\
+   ? NULL								\
+   : (&LINEMAPS_ORDINARY_MAPS (SET)[(MAP)->d.ordinary.included_from]))
 
 /* Nonzero if the map is at the bottom of the include stack.  */
-#define MAIN_FILE_P(MAP) ((MAP)->included_from < 0)
+#define MAIN_FILE_P(MAP)						\
+  ((linemap_check_ordinary (MAP)->d.ordinary.included_from < 0))
+
+#if defined ENABLE_CHECKING && (GCC_VERSION >= 2007)
+
+/* Assertion macro to be used in line-map code.  */
+#define linemap_assert(EXPR)			\
+  do {						\
+    if (! (EXPR))				\
+      abort ();					\
+  } while (0)
+
+/* Assert that MAP encodes locations of tokens that are not part of
+   the replacement-list of a macro expansion.  */
+#define linemap_check_ordinary(LINE_MAP) __extension__		\
+  ({linemap_assert (!linemap_macro_expansion_map_p (LINE_MAP)); \
+    (LINE_MAP);})
+#else
+#define linemap_assert(EXPR)
+#define linemap_check_ordinary(LINE_MAP) (LINE_MAP)
+#endif
 
+/* Encode and return a source_location from a column number. The
+   source line considered is the last source line used to call
+   linemap_line_start, i.e, the last source line which a location was
+   encoded from.  */
 extern source_location
-linemap_position_for_column (struct line_maps *set, unsigned int to_column);
+linemap_position_for_column (struct line_maps *, unsigned int);
+
+/* Encode and return a source location from a given line and
+   column.  */
+source_location linemap_position_for_line_and_column (struct line_map *,
+						      linenum_type,
+						      unsigned int);
+/* Return the file this map is for.  */
+#define LINEMAP_FILE(MAP)					\
+  (linemap_check_ordinary (MAP)->d.ordinary.to_file)
+
+/* Return the line number this map started encoding location from.  */
+#define LINEMAP_LINE(MAP)					\
+  (linemap_check_ordinary (MAP)->d.ordinary.to_line)
+
+/* Return a positive value if map encodes locations from a system
+   header, 0 otherwise. Returns 1 if MAP encodes locations in a
+   system header and 2 if it encodes locations in a C system header
+   that therefore needs to be extern "C" protected in C++.  */
+#define LINEMAP_SYSP(MAP)					\
+  (linemap_check_ordinary (MAP)->d.ordinary.sysp)
+
+/* Return a positive value if PRE denotes the location of a token that
+   comes before the token of POST, 0 if PRE denotes the location of
+   the same token as the token for POST, and a negative value
+   otherwise.  */
+int linemap_compare_locations (struct line_maps *set,
+			       source_location   pre,
+			       source_location   post);
+
+/* Return TRUE if LOC_A denotes the location a token that comes
+   topogically before the token denoted by location LOC_B, or if they
+   are equal.  */
+#define linemap_location_before_p(SET, LOC_A, LOC_B)	\
+  (linemap_compare_locations ((SET), (LOC_A), (LOC_B)) >= 0)
+
+typedef struct
+{
+  /* The name of the source file involved.  */
+  const char *file;
+
+  /* The line-location in the source file.  */
+  int line;
+
+  int column;
+
+  /* In a system header?. */
+  bool sysp;
+} expanded_location;
+
+/* This is enum is used by the function linemap_resolve_location
+   below.  The meaning of the values is explained in the comment of
+   that function.  */
+enum location_resolution_kind
+{
+  LRK_MACRO_EXPANSION_POINT,
+  LRK_SPELLING_LOCATION,
+  LRK_MACRO_DEFINITION_LOCATION
+};
+
+/* Resolve a virtual location into either a spelling location, an
+   expansion point location or a token argument replacement point
+   location.  Return the map that encodes the virtual location as well
+   as the resolved location.
+
+   If LOC is *NOT* the location of a token resulting from the
+   expansion of a macro, then the parameter LRK (which stands for
+   Location Resolution Kind) is ignored and the resulting location
+   just equals the one given in argument.
+
+   Now if LOC *IS* the location of a token resulting from the
+   expansion of a macro, this is what happens.
+
+   * If LRK is set to LRK_MACRO_EXPANSION_POINT
+   -------------------------------
+
+   The virtual location is resolved to the first macro expansion point
+   that led to this macro expansion.
+
+   * If LRK is set to LRK_SPELLING_LOCATION
+   -------------------------------------
+
+   The virtual location is resolved to the locus where the token has
+   been spelled in the source.   This can follow through all the macro
+   expansions that led to the token.
+
+   * If LRK is set to LRK_MACRO_DEFINITION_LOCATION
+   --------------------------------------
+
+   The virtual location is resolved to the locus of the token in the
+   context of the macro definition.
+
+   If LOC is the locus of a token that is an argument of a
+   function-like macro [replacing a parameter in the replacement list
+   of the macro] the virtual location is resolved to the locus of the
+   parameter that is replaced, in the context of the definition of the
+   macro.
+
+   If LOC is the locus of a token that is not an argument of a
+   function-like macro, then the function behaves as if LRK was set to
+   LRK_SPELLING_LOCATION.
+
+   If LOC_MAP is not NULL, *LOC_MAP is set to the map encoding the
+   returned location.  */
+
+source_location linemap_resolve_location (struct line_maps *,
+					  source_location loc,
+					  enum location_resolution_kind lrk,
+					  const struct line_map **loc_map);
+
+/* Suppose that LOC is the virtual location of a token coming from the
+   expansion of a macro M.  This function then steps up to get the
+   location L of the point where M got expanded.  If L is a spelling
+   location inside a macro expansion M', then this function returns
+   the point where M' was expanded.  LOC_MAP is an output parameter.
+   When non-NULL, *LOC_MAP is set the the map of the returned
+   location.  */
+source_location linemap_unwind_toward_expansion (struct line_maps *,
+						 source_location loc,
+						 const struct line_map **loc_map);
+
+/* Expand source code location LOC and return a user readable source
+   code location.  LOC must be a spelling (non-virtual) location.  */
+
+expanded_location linemap_expand_location (const struct line_map *,
+					   source_location loc);
+
+/* Expand source code location LOC and return a user readable source
+   code location.  LOC can be a virtual location.  The LRK parameter
+   is the same as for linemap_resolve_location.  */
+
+expanded_location linemap_expand_location_full (struct line_maps *,
+						source_location loc,
+						enum location_resolution_kind lrk);
 
 #endif /* !LIBCPP_LINE_MAP_H  */