Re: [PATCH 1/2] Fix sorting of enum values in FlagEnumerationPrinter

[Simon Marchi <simon.marchi@polymtl.ca>]

On 2016-01-20 09:41, Pedro Alves wrote:
> OK, I think that makes sense for cases like:
> 
>   enum flag_enum
>    {
>      FOO_MASK = 0x07,
>      FOO_1    = 0x01,
>      FOO_2    = 0x02,
>      FOO_3    = 0x04,
> 
>      BAR_MASK = 0x70,
>      BAR_1    = 0x10,
>      BAR_2    = 0x20,
>      BAR_3    = x040,
>    };
> 
> Would you mind augmenting the testsuite with something
> like this, then?
> 
> Thanks,
> Pedro Alves

Here is a v2:


 From 5d7a3227fa50594c1f5541550a07481583e027df Mon Sep 17 00:00:00 2001
 From: Simon Marchi <simon.marchi@polymtl.ca>
Date: Mon, 18 Jan 2016 21:35:18 -0500
Subject: [PATCH] Fix sorting of enum values in FlagEnumerationPrinter

The lambda function used to sort the enumerator list does not work
properly.  This list consists of tuples, (enum label, enum value).  The
key function returns x.enumval.  enumval not being defined for a tuple,
we see this exception in the test log:

   Python Exception <class 'AttributeError'> 'tuple' object has no 
attribute 'enumval'

The function should return the second item of the tuple, which is the
enumval.

The pretty-printer still worked mostly correctly, except that the
enumeration values were not sorted.  The test still passed because the
enumeration values are already sorted where they are defined.  The test
also passed despite the exception being printed, because the right 
output
was printed after the exception:

   print (enum flag_enum) (FLAG_1)
   Python Exception <type 'exceptions.AttributeError'> 'tuple' objecthas 
no attribute 'enumval':M
   $7 = 0x1 [FLAG_1]
   (gdb) PASS: gdb.python/py-pp-maint.exp: print FLAG_1

New in v2:

- Improved test case, I stole Pedro's example directly.  It verifies
   that the sorting of enumerators by value works, by checking that
   printing FOO_MASK appears as FOO_1 | FOO_2 | FOO_3.

   I noticed that I could change the regexps to almost anything and the
   tests would still pass.  I think it was because of the | in there.  I
   made them more robust by using string_to_regexp.  I used curly braces
   { } instead of quoting marks " " for strings, so that I could use
   square brackets [ ] in them without having to escape them all.  I also
   removed the "message" part of the tests, since they are redundant with
   the command, and it's just more maintenance to have to update them.

   Tested with Python 2.7 and 3.5.

gdb/ChangeLog:

	* python/lib/gdb/printing.py (FlagEnumerationPrinter.__call__):
	Fix enumerators sort key function.

gdb/testsuite/ChangeLog:

	* gdb.python/py-pp-maint.exp: Change/add enum flag tests.
	* gdb.python/py-pp-maint.c (enum flag_enum): Use more complex
	enum flag values.
---
  gdb/python/lib/gdb/printing.py           |  2 +-
  gdb/testsuite/gdb.python/py-pp-maint.c   | 16 ++++++++++++----
  gdb/testsuite/gdb.python/py-pp-maint.exp | 27 
++++++++++++++++++---------
  3 files changed, 31 insertions(+), 14 deletions(-)

diff --git a/gdb/python/lib/gdb/printing.py 
b/gdb/python/lib/gdb/printing.py
index 5160581..63c3aeb 100644
--- a/gdb/python/lib/gdb/printing.py
+++ b/gdb/python/lib/gdb/printing.py
@@ -263,7 +263,7 @@ class FlagEnumerationPrinter(PrettyPrinter):
                  self.enumerators.append((field.name, field.enumval))
              # Sorting the enumerators by value usually does the right
              # thing.
-            self.enumerators.sort(key = lambda x: x.enumval)
+            self.enumerators.sort(key = lambda x: x[1])

          if self.enabled:
              return _EnumInstance(self.enumerators, val)
diff --git a/gdb/testsuite/gdb.python/py-pp-maint.c 
b/gdb/testsuite/gdb.python/py-pp-maint.c
index 657dfd7..d750496 100644
--- a/gdb/testsuite/gdb.python/py-pp-maint.c
+++ b/gdb/testsuite/gdb.python/py-pp-maint.c
@@ -17,12 +17,20 @@

  #include <string.h>

+
  enum flag_enum
    {
-    FLAG_1 = 1,
-    FLAG_2 = 2,
-    FLAG_3 = 4,
-    ALL = FLAG_1 | FLAG_2 | FLAG_3
+    /* Define the enumeration values in an unsorted manner to verify 
that we
+       effectively sort them by value.  */
+    FOO_MASK = 0x07,
+    FOO_1    = 0x01,
+    FOO_2    = 0x02,
+    FOO_3    = 0x04,
+
+    BAR_MASK = 0x70,
+    BAR_1    = 0x10,
+    BAR_2    = 0x20,
+    BAR_3    = 0x40,
    };

  enum flag_enum fval;
diff --git a/gdb/testsuite/gdb.python/py-pp-maint.exp 
b/gdb/testsuite/gdb.python/py-pp-maint.exp
index db0768f..9dbe19f 100644
--- a/gdb/testsuite/gdb.python/py-pp-maint.exp
+++ b/gdb/testsuite/gdb.python/py-pp-maint.exp
@@ -119,14 +119,23 @@ gdb_test "print flt" " = x=<42> y=<43>" \
  gdb_test "print ss" " = a=<a=<1> b=<$hex>> b=<a=<2> b=<$hex>>" \
      "print ss re-enabled"

-gdb_test "print (enum flag_enum) (FLAG_1)" \
-    " = 0x1 .FLAG_1." \
-    "print FLAG_1"
+gdb_test "print (enum flag_enum) (FOO_1)" \
+    [string_to_regexp { = 0x1 [FOO_1]}]

-gdb_test "print (enum flag_enum) (FLAG_1 | FLAG_3)" \
-    " = 0x5 .FLAG_1 | FLAG_3." \
-    "print FLAG_1 | FLAG_3"
+gdb_test "print (enum flag_enum) (BAR_3)" \
+    [string_to_regexp { = 0x40 [BAR_3]}]

-gdb_test "print (enum flag_enum) (4 + 8)" \
-    " = 0xc .FLAG_1 | <unknown: 0x8>." \
-    "print FLAG_1 | 8"
+gdb_test "print (enum flag_enum) (BAR_2 | FOO_2)" \
+    [string_to_regexp { = 0x22 [FOO_2 | BAR_2]}]
+
+gdb_test "print (enum flag_enum) (FOO_1 | FOO_2 | FOO_3)" \
+    [string_to_regexp { = 0x7 [FOO_1 | FOO_2 | FOO_3]}]
+
+gdb_test "print (enum flag_enum) (FOO_MASK)" \
+    [string_to_regexp { = 0x7 [FOO_1 | FOO_2 | FOO_3]}]
+
+gdb_test "print (enum flag_enum) (FOO_MASK | (BAR_MASK & ~BAR_2))" \
+    [string_to_regexp { = 0x57 [FOO_1 | FOO_2 | FOO_3 | BAR_1 | 
BAR_3]}]
+
+gdb_test "print (enum flag_enum) (0x4 + 0x8)" \
+    [string_to_regexp { = 0xc [FOO_3 | <unknown: 0x8>]}]
-- 
2.7.0