Hi,
Without the patch, I see these error messages with gdb 8.3:
(gdb) Python Exception <class 'gdb.error'> 'fclose@@GLIBC_2.2.5' has
unknown return type; cast the call to its declared return type:
(gdb) Error occurred in Python: 'fclose@@GLIBC_2.2.5' has unknown
return type; cast the call to its declared return type
One doesn't have to use python to reproduce that: start debugging cc1
and issue
(gdb) call fopen ("", "")
This actually looks like a GDB bug: from looking at cc1's (built with
either -g, or -ggdb3) DWARF with either dwarfdump, or readelf I see that
there is info about the return type (for fopen it's FILE *, and `ptype
FILE` in gdb gives the full struct).
Tom, you contributed the {dot,dump}-fn functions. Do they still work
for you without the patch? (And if so, do you happen to have debuginfo
for libc installed on you machine?)
I think, the patch itself is obvious (as a workaround). I've only
tested it with the version of GDB I have (8.3, which is the latest
release), but expect this to work for older versions as well.
(Comparisons of gdb.Value's returned from parse_and_eval, like fp == 0
and their conversion to python strings in "%s" % fp work automagically.)
* gdbhooks.py (DumpFn.invoke): Add explicit casts of return values of
fopen and fclose to their respective types.
(DotFn.invoke): Ditto.
---
gcc/gdbhooks.py | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/gcc/gdbhooks.py b/gcc/gdbhooks.py
index 15f9738aeee..c68bffb4d1a 100644
--- a/gcc/gdbhooks.py
+++ b/gcc/gdbhooks.py
@@ -773,18 +773,17 @@ class DumpFn(gdb.Command):
f.close()
# Open file
- fp = gdb.parse_and_eval("fopen (\"%s\", \"w\")" % filename)
+ fp = gdb.parse_and_eval("(FILE *) fopen (\"%s\", \"w\")" % filename)
if fp == 0:
print ("Could not open file: %s" % filename)
return
- fp = "(FILE *)%u" % fp
# Dump function to file
_ = gdb.parse_and_eval("dump_function_to_file (%s, %s, %u)" %
(func, fp, flags))
# Close file
- ret = gdb.parse_and_eval("fclose (%s)" % fp)
+ ret = gdb.parse_and_eval("(int) fclose (%s)" % fp)
if ret != 0:
print ("Could not close file: %s" % filename)
return
@@ -843,11 +842,10 @@ class DotFn(gdb.Command):
# Close and reopen temp file to get C FILE*
f.close()
- fp = gdb.parse_and_eval("fopen (\"%s\", \"w\")" % filename)
+ fp = gdb.parse_and_eval("(FILE *) fopen (\"%s\", \"w\")" % filename)
if fp == 0:
print("Cannot open temp file")
return
- fp = "(FILE *)%u" % fp
# Write graph to temp file
_ = gdb.parse_and_eval("start_graph_dump (%s, \"<debug>\")" % fp)
@@ -856,7 +854,7 @@ class DotFn(gdb.Command):
_ = gdb.parse_and_eval("end_graph_dump (%s)" % fp)
# Close temp file
- ret = gdb.parse_and_eval("fclose (%s)" % fp)
+ ret = gdb.parse_and_eval("(int) fclose (%s)" % fp)
if ret != 0:
print("Could not close temp file: %s" % filename)
return
--
2.22.0
--
Vlad
