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[Emacs-diffs] master 2a22a65: Improve .gdbinit Lisp value pretty-printin
From: |
Paul Eggert |
Subject: |
[Emacs-diffs] master 2a22a65: Improve .gdbinit Lisp value pretty-printing |
Date: |
Mon, 29 May 2017 20:15:43 -0400 (EDT) |
branch: master
commit 2a22a65fe1fd7f75480f6dcfe404b5ce43a2b821
Author: Paul Eggert <address@hidden>
Commit: Paul Eggert <address@hidden>
Improve .gdbinit Lisp value pretty-printing
* 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.
---
src/.gdbinit | 51 +++++++++++++++++++++++++++++++++++++++++++++------
1 file changed, 45 insertions(+), 6 deletions(-)
diff --git a/src/.gdbinit b/src/.gdbinit
index 80aa95b..b5a974b 100644
--- a/src/.gdbinit
+++ b/src/.gdbinit
@@ -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:
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