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Improve .gdbinit Lisp value pretty-printing

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* src/.gdbinit (to_string): Use an unsigned representation for
Lisp values, as requested by Eli Zaretskii (Bug#27098).
Also, use "make_number(N)" for Lisp integers.
This commit is contained in:
Paul Eggert 2017-05-29 17:15:11 -07:00
parent 2349f1df1b
commit 2a22a65fe1
1 changed files with 45 additions and 6 deletions
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51
src/.gdbinit
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@ -1300,18 +1300,52 @@ if hasattr(gdb, 'printing'):
def to_string (self):
"Yield a string that can be fed back into GDB."
# This implementation should work regardless of C compiler, and
# it should not attempt to run any code in the inferior.
EMACS_INT_WIDTH = int(gdb.lookup_symbol("EMACS_INT_WIDTH")[0].value())
USE_LSB_TAG = int(gdb.lookup_symbol("USE_LSB_TAG")[0].value())
GCTYPEBITS = 3
VALBITS = EMACS_INT_WIDTH - GCTYPEBITS
Lisp_Int0 = 2
Lisp_Int1 = 6 if USE_LSB_TAG else 3
# Unpack the Lisp value from its containing structure, if necessary.
val = self.val
basic_type = gdb.types.get_basic_type (val.type)
if (basic_type.code == gdb.TYPE_CODE_STRUCT
and gdb.types.has_field (basic_type, "i")):
val = val["i"]
# Yield "XIL(N)", where N is a C integer. This helps humans
# distinguish Lisp_Object values from ordinary integers even
# when Lisp_Object is an integer. Perhaps some day the
# pretty-printing could be fancier.
# For nil, yield "XIL(0)", which is easier to read than "XIL(0x0)".
if not val:
return "XIL(0)" # Easier to read than "XIL(0x0)".
return "XIL(0x%x)" % int(val)
return "XIL(0)"
# Extract the integer representation of the value and its Lisp type.
ival = int(val)
itype = ival >> (0 if USE_LSB_TAG else VALBITS)
itype = itype & ((1 << GCTYPEBITS) - 1)
# For a Lisp integer N, yield "make_number(N)".
if itype == Lisp_Int0 or itype == Lisp_Int1:
if USE_LSB_TAG:
ival = ival >> (GCTYPEBITS - 1)
elif (ival >> VALBITS) & 1:
ival = ival | (-1 << VALBITS)
else:
ival = ival & ((1 << VALBITS) - 1)
return "make_number(%d)" % ival
# For non-integers other than nil yield "XIL(N)", where N is a C integer.
# This helps humans distinguish Lisp_Object values from ordinary
# integers even when Lisp_Object is an integer.
# Perhaps some day the pretty-printing could be fancier.
# Prefer the unsigned representation to negative values, converting
# by hand as val.cast(gdb.lookup_type("EMACS_UINT") does not work in
# GDB 7.12.1; see <http://patchwork.sourceware.org/patch/11557/>.
if ival < 0:
ival = ival + (1 << EMACS_INT_WIDTH)
return "XIL(0x%x)" % ival
def build_pretty_printer ():
pp = Emacs_Pretty_Printers ("Emacs")
@ -1321,3 +1355,8 @@ if hasattr(gdb, 'printing'):
gdb.printing.register_pretty_printer (gdb.current_objfile (),
build_pretty_printer (), True)
end
# GDB mishandles indentation with leading tabs when feeding it to Python.
# Local Variables:
# indent-tabs-mode: nil
# End: