[v9,04/11] gdb: add HtabPrinter to gdb-gdb.py.in
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Commit Message
From: Simon Marchi <simon.marchi@efficios.com>
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
Reviewed-By: Tom Tromey <tom@tromey.com>
---
gdb/gdb-gdb.py.in | 31 +++++++++++++++++++++++++
gdb/testsuite/gdb.gdb/python-helper.exp | 3 +++
2 files changed, 34 insertions(+)
@@ -369,6 +369,35 @@ class IntrusiveListPrinter:
return self._children_generator()
+class HtabPrinter:
+ """Pretty-printer for htab_t hash tables."""
+
+ def __init__(self, val):
+ self._val = val
+
+ 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(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 type_lookup_function(val):
"""A routine that returns the correct pretty printer for VAL
if appropriate. Returns None otherwise.
@@ -383,6 +412,8 @@ 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
@@ -208,6 +208,9 @@ proc test_python_helper {} {
" cplus_stuff = $hex}"]
gdb_test -prompt $outer_prompt_re "print *type->main_type" $answer
+ # Test the htab_t pretty-printer.
+ gdb_test -prompt $outer_prompt_re "print all_bfds" "htab_t with ${::decimal} elements = \\{${::hex}.*\\}"
+
return 0
}