From: Simon Marchi <simon.marchi@efficios.com>
To: gdb-patches@sourceware.org
Cc: Simon Marchi <simon.marchi@efficios.com>
Subject: [PATCH] gdb: add HtabPrinter to gdb-gdb.py.in
Date: Thu, 9 Feb 2023 14:50:56 -0500 [thread overview]
Message-ID: <20230209195056.100681-1-simon.marchi@efficios.com> (raw)
When debugging GDB, I find it a bit tedious to inspect htab_t objects.
It is possible to find the entries by poking at the fields, but it's
annoying to do each time. I think a pretty printer would help. Add a
basic one to gdb-gdb.py.
The pretty printer advertises itself as "array-like", and the result
looks like:
(top-gdb) p bfcache
$3 = htab_t with 3 elements = {0x6210003252a0, 0x62100032caa0, 0x62100033baa0}
The htab_t itself doesn't know about the type of pointed objects. But
it's easy enough to cast the addresses to the right type to use them:
(top-gdb) print *((btrace_frame_cache *) 0x6210003252a0)
$6 = {tp = 0x61700002ed80, frame = 0x6210003251e0, bfun = 0x62000000b390}
Change-Id: Ia692e3555fe7a117b7ec087840246b1260a704c6
---
gdb/gdb-gdb.py.in | 36 ++++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
diff --git a/gdb/gdb-gdb.py.in b/gdb/gdb-gdb.py.in
index 95b7d84966f0..31ce80bb1e44 100644
--- a/gdb/gdb-gdb.py.in
+++ b/gdb/gdb-gdb.py.in
@@ -369,6 +369,40 @@ class IntrusiveListPrinter:
return self._children_generator()
+class HtabPrinter:
+ """Pretty-printer for htab_t hash tables."""
+
+ def __init__(self, val):
+ self._val = val
+ self._entries = val["entries"]
+ self._size = int(val["size"])
+
+ def display_hint(self):
+ return "array"
+
+ def to_string(self):
+ n = int(self._val["n_elements"]) - int(self._val["n_deleted"])
+ return "htab_t with {} elements".format(n)
+
+ def _children_generator(self):
+ size = int(self._val["size"])
+ entries = self._val["entries"]
+
+ child_i = 0
+ for entries_i in range(size):
+ entry = entries[entries_i]
+ # 0 (NULL pointer) means there's nothing, 1 (HTAB_DELETED_ENTRY)
+ # means there was something, but is now deleted.
+ if int(entry) in (0, 1):
+ continue
+
+ yield (str(child_i), entry)
+ child_i += 1
+
+ def children(self):
+ return self._children_generator()
+
+
def type_lookup_function(val):
"""A routine that returns the correct pretty printer for VAL
if appropriate. Returns None otherwise.
@@ -383,6 +417,8 @@ def type_lookup_function(val):
return CoreAddrPrettyPrinter(val)
elif tag is not None and tag.startswith("intrusive_list<"):
return IntrusiveListPrinter(val)
+ elif name == "htab_t":
+ return HtabPrinter(val)
return None
--
2.39.1
next reply other threads:[~2023-02-09 19:50 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-09 19:50 Simon Marchi [this message]
2023-02-09 19:52 ` Simon Marchi
2023-02-27 18:10 ` Tom Tromey
2023-02-28 4:23 ` Simon Marchi
2023-02-28 14:30 ` Tom Tromey
2023-02-28 16:08 ` Simon Marchi
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