diff mbox

[01/10] Improvements to description of source_location in line-map.h

Message ID 1445632918-29617-2-git-send-email-dmalcolm@redhat.com
State New
Headers show

Commit Message

David Malcolm Oct. 23, 2015, 8:41 p.m. UTC 
libcpp/ChangeLog:
	* include/line-map.h (source_location): In the table in the
	descriptive comment, show UNKNOWN_LOCATION, BUILTINS_LOCATION,
	LINE_MAP_MAX_LOCATION_WITH_COLS, LINE_MAP_MAX_SOURCE_LOCATION.
	Add notes about ad-hoc values.
---
 libcpp/include/line-map.h | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

Comments

Jeff Law Oct. 23, 2015, 9:01 p.m. UTC | #1 
On 10/23/2015 02:41 PM, David Malcolm wrote:
> libcpp/ChangeLog:
> 	* include/line-map.h (source_location): In the table in the
> 	descriptive comment, show UNKNOWN_LOCATION, BUILTINS_LOCATION,
> 	LINE_MAP_MAX_LOCATION_WITH_COLS, LINE_MAP_MAX_SOURCE_LOCATION.
> 	Add notes about ad-hoc values.
If this is documenting current state, then it's OK to go in now.  If 
it's documenting future state, then it can go in with the rest of the 
patches.

jeff
diff mbox

Patch

diff --git a/libcpp/include/line-map.h b/libcpp/include/line-map.h
index bc747c1..30bad87 100644
--- a/libcpp/include/line-map.h
+++ b/libcpp/include/line-map.h
@@ -59,8 +59,10 @@  typedef unsigned int linenum_type;
 
   Actual     | Value                         | Meaning
   -----------+-------------------------------+-------------------------------
-  0x00000000 |                               | Reserved for use by libcpp
-  0x00000001 | RESERVED_LOCATION_COUNT - 1   | Reserved for use by libcpp
+  0x00000000 | UNKNOWN_LOCATION (gcc/input.h)| Unknown/invalid location.
+  -----------+-------------------------------+-------------------------------
+  0x00000001 | BUILTINS_LOCATION             | The location for declarations
+             |   (gcc/input.h)               | in "<built-in>"
   -----------+-------------------------------+-------------------------------
   0x00000002 | RESERVED_LOCATION_COUNT       | The first location to be
              | (also                         | handed out, and the
@@ -94,6 +96,16 @@  typedef unsigned int linenum_type;
              |
              |                    (unallocated integers)
              |
+  0x60000000 | LINE_MAP_MAX_LOCATION_WITH_COLS
+             |   Beyond this point, ordinary linemaps have 0 bits per column:
+             |   each increment of the value corresponds to a new source line.
+             |
+  0x70000000 | LINE_MAP_MAX_SOURCE_LOCATION
+             |   Beyond the point, we give up on ordinary maps; attempts to
+             |   create locations in them lead to UNKNOWN_LOCATION (0).
+             |
+             |                    (unallocated integers)
+             |
              |                   Macro maps grow this way
              |                   ^^^^^^^^^^^^^^^^^^^^^^^^
              |                               |
@@ -107,10 +119,11 @@  typedef unsigned int linenum_type;
              | macromap[1]->start_location   | Start of macro map 1
   -----------+-------------------------------+-------------------------------
              | macromap[0]->start_location   | Start of macro map 0
-  0x7fffffff | MAX_SOURCE_LOCATION           |
+  0x7fffffff | MAX_SOURCE_LOCATION           | Also used as a mask for
+             |                               | accessing the ad-hoc data table
   -----------+-------------------------------+-------------------------------
-  0x80000000 | Start of ad-hoc values        |
-  ...        |                               |
+  0x80000000 | Start of ad-hoc values; the lower 31 bits are used as an index
+  ...        | into the line_table->location_adhoc_data_map.data array.
   0xffffffff | UINT_MAX                      |
   -----------+-------------------------------+-------------------------------