# Python hooks for gdb for debugging GCC
-# Copyright (C) 2013 Free Software Foundation, Inc.
+# Copyright (C) 2013-2020 Free Software Foundation, Inc.
# Contributed by David Malcolm <dmalcolm@redhat.com>
Callgraph nodes are printed with the name of the function decl, if
available:
(gdb) frame 5
- #5 0x00000000006c288a in expand_function (node=<cgraph_node* 0x7ffff0312720 "foo">) at ../../src/gcc/cgraphunit.c:1594
+ #5 0x00000000006c288a in expand_function (node=<cgraph_node* 0x7ffff0312720 "foo"/12345>) at ../../src/gcc/cgraphunit.c:1594
1594 execute_pass_list (g->get_passes ()->all_passes);
(gdb) p node
- $1 = <cgraph_node* 0x7ffff0312720 "foo">
+ $1 = <cgraph_node* 0x7ffff0312720 "foo"/12345>
+
+Similarly for symtab_node and varpool_node classes.
+
+Cgraph edges are printed with the name of caller and callee:
+ (gdb) p this->callees
+ $4 = <cgraph_edge* 0x7fffe25aa000 (<cgraph_node * 0x7fffe62b22e0 "_GLOBAL__sub_I__ZN5Pooma5pinfoE"/19660> -> <cgraph_node * 0x7fffe620f730 "__static_initialization_and_destruction_1"/19575>)>
+
+IPA reference follow very similar format:
+ (gdb) Value returned is $5 = <ipa_ref* 0x7fffefcb80c8 (<symtab_node * 0x7ffff562f000 "__dt_base "/875> -> <symtab_node * 0x7fffe795f000 "_ZTVN6Smarts8RunnableE"/16056>:IPA_REF_ADDR)>
vec<> pointers are printed as the address followed by the elements in
braces. Here's a length 2 vec:
(gdb) p bb->preds->m_vecdata[1]
$21 = <edge 0x7ffff044d3b8 (4 -> 5)>
"""
+import os.path
import re
+import sys
+import tempfile
import gdb
import gdb.printing
# ...and look up specific values for use later:
IDENTIFIER_NODE = tree_code_dict['IDENTIFIER_NODE']
TYPE_DECL = tree_code_dict['TYPE_DECL']
+SSA_NAME = tree_code_dict['SSA_NAME']
# Similarly for "enum tree_code_class" (tree.h):
tree_code_class_dict = gdb.types.make_enum_dict(gdb.lookup_type('enum tree_code_class'))
tcc_type = tree_code_class_dict['tcc_type']
tcc_declaration = tree_code_class_dict['tcc_declaration']
+# Python3 has int() with arbitrary precision (bignum). Python2 int() is 32-bit
+# on 32-bit hosts but remote targets may have 64-bit pointers there; Python2
+# long() is always 64-bit but Python3 no longer has anything named long.
+def intptr(gdbval):
+ return long(gdbval) if sys.version_info.major == 2 else int(gdbval)
+
class Tree:
"""
Wrapper around a gdb.Value for a tree, with various methods
self.gdbval = gdbval
def is_nonnull(self):
- return long(self.gdbval)
+ return intptr(self.gdbval)
def TREE_CODE(self):
"""
# like gcc/print-tree.c:print_node_brief
# #define TREE_CODE(NODE) ((enum tree_code) (NODE)->base.code)
# tree_code_name[(int) TREE_CODE (node)])
- if long(self.gdbval) == 0:
+ if intptr(self.gdbval) == 0:
return '<tree 0x0>'
val_TREE_CODE = self.node.TREE_CODE()
# extern const enum tree_code_class tree_code_type[];
# #define TREE_CODE_CLASS(CODE) tree_code_type[(int) (CODE)]
+ if val_TREE_CODE == 0xa5a5:
+ return '<ggc_freed 0x%x>' % intptr(self.gdbval)
+
val_tree_code_type = gdb.parse_and_eval('tree_code_type')
val_tclass = val_tree_code_type[val_TREE_CODE]
val_tree_code_name = gdb.parse_and_eval('tree_code_name')
- val_code_name = val_tree_code_name[long(val_TREE_CODE)]
- #print val_code_name.string()
-
- result = '<%s 0x%x' % (val_code_name.string(), long(self.gdbval))
- if long(val_tclass) == tcc_declaration:
+ val_code_name = val_tree_code_name[intptr(val_TREE_CODE)]
+ #print(val_code_name.string())
+
+ try:
+ result = '<%s 0x%x' % (val_code_name.string(), intptr(self.gdbval))
+ except:
+ return '<tree 0x%x>' % intptr(self.gdbval)
+ if intptr(val_tclass) == tcc_declaration:
tree_DECL_NAME = self.node.DECL_NAME()
if tree_DECL_NAME.is_nonnull():
result += ' %s' % tree_DECL_NAME.IDENTIFIER_POINTER()
else:
pass # TODO: labels etc
- elif long(val_tclass) == tcc_type:
+ elif intptr(val_tclass) == tcc_type:
tree_TYPE_NAME = Tree(self.gdbval['type_common']['name'])
if tree_TYPE_NAME.is_nonnull():
if tree_TYPE_NAME.TREE_CODE() == IDENTIFIER_NODE:
result += ' %s' % tree_TYPE_NAME.DECL_NAME().IDENTIFIER_POINTER()
if self.node.TREE_CODE() == IDENTIFIER_NODE:
result += ' %s' % self.node.IDENTIFIER_POINTER()
+ elif self.node.TREE_CODE() == SSA_NAME:
+ result += ' %u' % self.gdbval['base']['u']['version']
# etc
result += '>'
return result
# Callgraph pretty-printers
######################################################################
-class CGraphNodePrinter:
+class SymtabNodePrinter:
def __init__(self, gdbval):
self.gdbval = gdbval
def to_string (self):
- result = '<cgraph_node* 0x%x' % long(self.gdbval)
- if long(self.gdbval):
+ t = str(self.gdbval.type)
+ result = '<%s 0x%x' % (t, intptr(self.gdbval))
+ if intptr(self.gdbval):
# symtab_node::name calls lang_hooks.decl_printable_name
# default implementation (lhd_decl_printable_name) is:
# return IDENTIFIER_POINTER (DECL_NAME (decl));
tree_decl = Tree(self.gdbval['decl'])
- result += ' "%s"' % tree_decl.DECL_NAME().IDENTIFIER_POINTER()
+ result += ' "%s"/%d' % (tree_decl.DECL_NAME().IDENTIFIER_POINTER(), self.gdbval['order'])
+ result += '>'
+ return result
+
+class CgraphEdgePrinter:
+ def __init__(self, gdbval):
+ self.gdbval = gdbval
+
+ def to_string (self):
+ result = '<cgraph_edge* 0x%x' % intptr(self.gdbval)
+ if intptr(self.gdbval):
+ src = SymtabNodePrinter(self.gdbval['caller']).to_string()
+ dest = SymtabNodePrinter(self.gdbval['callee']).to_string()
+ result += ' (%s -> %s)' % (src, dest)
+ result += '>'
+ return result
+
+class IpaReferencePrinter:
+ def __init__(self, gdbval):
+ self.gdbval = gdbval
+
+ def to_string (self):
+ result = '<ipa_ref* 0x%x' % intptr(self.gdbval)
+ if intptr(self.gdbval):
+ src = SymtabNodePrinter(self.gdbval['referring']).to_string()
+ dest = SymtabNodePrinter(self.gdbval['referred']).to_string()
+ result += ' (%s -> %s:%s)' % (src, dest, str(self.gdbval['use']))
+ result += '>'
+ return result
+
+######################################################################
+# Dwarf DIE pretty-printers
+######################################################################
+
+class DWDieRefPrinter:
+ def __init__(self, gdbval):
+ self.gdbval = gdbval
+
+ def to_string (self):
+ if intptr(self.gdbval) == 0:
+ return '<dw_die_ref 0x0>'
+ result = '<dw_die_ref 0x%x' % intptr(self.gdbval)
+ result += ' %s' % self.gdbval['die_tag']
+ if intptr(self.gdbval['die_parent']) != 0:
+ result += ' <parent=0x%x %s>' % (intptr(self.gdbval['die_parent']),
+ self.gdbval['die_parent']['die_tag'])
+
result += '>'
return result
self.gdbval = gdbval
def to_string (self):
- if long(self.gdbval) == 0:
+ if intptr(self.gdbval) == 0:
return '<gimple 0x0>'
val_gimple_code = self.gdbval['code']
val_gimple_code_name = gdb.parse_and_eval('gimple_code_name')
- val_code_name = val_gimple_code_name[long(val_gimple_code)]
+ val_code_name = val_gimple_code_name[intptr(val_gimple_code)]
result = '<%s 0x%x' % (val_code_name.string(),
- long(self.gdbval))
+ intptr(self.gdbval))
result += '>'
return result
self.gdbval = gdbval
def to_string (self):
- result = '<basic_block 0x%x' % long(self.gdbval)
- if long(self.gdbval):
- result += ' (%s)' % bb_index_to_str(long(self.gdbval['index']))
+ result = '<basic_block 0x%x' % intptr(self.gdbval)
+ if intptr(self.gdbval):
+ result += ' (%s)' % bb_index_to_str(intptr(self.gdbval['index']))
result += '>'
return result
self.gdbval = gdbval
def to_string (self):
- result = '<edge 0x%x' % long(self.gdbval)
- if long(self.gdbval):
- src = bb_index_to_str(long(self.gdbval['src']['index']))
- dest = bb_index_to_str(long(self.gdbval['dest']['index']))
+ result = '<edge 0x%x' % intptr(self.gdbval)
+ if intptr(self.gdbval):
+ src = bb_index_to_str(intptr(self.gdbval['src']['index']))
+ dest = bb_index_to_str(intptr(self.gdbval['dest']['index']))
result += ' (%s -> %s)' % (src, dest)
result += '>'
return result
def GET_RTX_LENGTH(code):
val_rtx_length = gdb.parse_and_eval('rtx_length')
- return long(val_rtx_length[code])
+ return intptr(val_rtx_length[code])
def GET_RTX_NAME(code):
val_rtx_name = gdb.parse_and_eval('rtx_name')
"""
# We use print_inline_rtx to avoid a trailing newline
gdb.execute('call print_inline_rtx (stderr, (const_rtx) %s, 0)'
- % long(self.gdbval))
+ % intptr(self.gdbval))
return ''
# or by hand; based on gcc/print-rtl.c:print_rtx
result = ('<rtx_def 0x%x'
- % (long(self.gdbval)))
+ % (intptr(self.gdbval)))
code = self.rtx.GET_CODE()
result += ' (%s' % GET_RTX_NAME(code)
format_ = GET_RTX_FORMAT(code)
for i in range(GET_RTX_LENGTH(code)):
- print format_[i]
+ print(format_[i])
result += ')>'
return result
self.gdbval = gdbval
def to_string (self):
- result = '<opt_pass* 0x%x' % long(self.gdbval)
- if long(self.gdbval):
+ result = '<opt_pass* 0x%x' % intptr(self.gdbval)
+ if intptr(self.gdbval):
result += (' "%s"(%i)'
% (self.gdbval['name'].string(),
- long(self.gdbval['static_pass_number'])))
+ intptr(self.gdbval['static_pass_number'])))
result += '>'
return result
def to_string (self):
# A trivial implementation; prettyprinting the contents is done
# by gdb calling the "children" method below.
- return '0x%x' % long(self.gdbval)
+ return '0x%x' % intptr(self.gdbval)
def children (self):
- if long(self.gdbval) == 0:
+ if intptr(self.gdbval) == 0:
return
m_vecpfx = self.gdbval['m_vecpfx']
m_num = m_vecpfx['m_num']
######################################################################
+class MachineModePrinter:
+ def __init__(self, gdbval):
+ self.gdbval = gdbval
+
+ def to_string (self):
+ name = str(self.gdbval['m_mode'])
+ return name[2:] if name.startswith('E_') else name
+
+######################################################################
+
+class OptMachineModePrinter:
+ def __init__(self, gdbval):
+ self.gdbval = gdbval
+
+ def to_string (self):
+ name = str(self.gdbval['m_mode'])
+ if name == 'E_VOIDmode':
+ return '<None>'
+ return name[2:] if name.startswith('E_') else name
+
+######################################################################
+
# TODO:
# * hashtab
# * location_t
def __init__(self, name):
super(GdbPrettyPrinters, self).__init__(name, [])
- def add_printer_for_types(self, name, class_, types):
- self.subprinters.append(GdbSubprinterTypeList(name, class_, types))
+ def add_printer_for_types(self, types, name, class_):
+ self.subprinters.append(GdbSubprinterTypeList(types, name, class_))
- def add_printer_for_regex(self, name, class_, regex):
- self.subprinters.append(GdbSubprinterRegex(name, class_, regex))
+ def add_printer_for_regex(self, regex, name, class_):
+ self.subprinters.append(GdbSubprinterRegex(regex, name, class_))
def __call__(self, gdbval):
type_ = gdbval.type.unqualified()
def build_pretty_printer():
pp = GdbPrettyPrinters('gcc')
- pp.add_printer_for_types(['tree'],
+ pp.add_printer_for_types(['tree', 'const_tree'],
'tree', TreePrinter)
- pp.add_printer_for_types(['cgraph_node *'],
- 'cgraph_node', CGraphNodePrinter)
- pp.add_printer_for_types(['gimple', 'gimple_statement_base *'],
+ pp.add_printer_for_types(['cgraph_node *', 'varpool_node *', 'symtab_node *'],
+ 'symtab_node', SymtabNodePrinter)
+ pp.add_printer_for_types(['cgraph_edge *'],
+ 'cgraph_edge', CgraphEdgePrinter)
+ pp.add_printer_for_types(['ipa_ref *'],
+ 'ipa_ref', IpaReferencePrinter)
+ pp.add_printer_for_types(['dw_die_ref'],
+ 'dw_die_ref', DWDieRefPrinter)
+ pp.add_printer_for_types(['gimple', 'gimple *',
+
+ # Keep this in the same order as gimple.def:
+ 'gimple_cond', 'const_gimple_cond',
+ 'gimple_statement_cond *',
+ 'gimple_debug', 'const_gimple_debug',
+ 'gimple_statement_debug *',
+ 'gimple_label', 'const_gimple_label',
+ 'gimple_statement_label *',
+ 'gimple_switch', 'const_gimple_switch',
+ 'gimple_statement_switch *',
+ 'gimple_assign', 'const_gimple_assign',
+ 'gimple_statement_assign *',
+ 'gimple_bind', 'const_gimple_bind',
+ 'gimple_statement_bind *',
+ 'gimple_phi', 'const_gimple_phi',
+ 'gimple_statement_phi *'],
+
'gimple',
GimplePrinter)
pp.add_printer_for_types(['basic_block', 'basic_block_def *'],
'vec',
VecPrinter)
+ pp.add_printer_for_regex(r'opt_mode<(\S+)>',
+ 'opt_mode', OptMachineModePrinter)
+ pp.add_printer_for_types(['opt_scalar_int_mode',
+ 'opt_scalar_float_mode',
+ 'opt_scalar_mode'],
+ 'opt_mode', OptMachineModePrinter)
+ pp.add_printer_for_regex(r'pod_mode<(\S+)>',
+ 'pod_mode', MachineModePrinter)
+ pp.add_printer_for_types(['scalar_int_mode_pod',
+ 'scalar_mode_pod'],
+ 'pod_mode', MachineModePrinter)
+ for mode in ('scalar_mode', 'scalar_int_mode', 'scalar_float_mode',
+ 'complex_mode'):
+ pp.add_printer_for_types([mode], mode, MachineModePrinter)
+
return pp
gdb.printing.register_pretty_printer(
gdb.current_objfile(),
- build_pretty_printer())
+ build_pretty_printer(),
+ replace=True)
+
+def find_gcc_source_dir():
+ # Use location of global "g" to locate the source tree
+ sym_g = gdb.lookup_global_symbol('g')
+ path = sym_g.symtab.filename # e.g. '../../src/gcc/context.h'
+ srcdir = os.path.split(path)[0] # e.g. '../../src/gcc'
+ return srcdir
+
+class PassNames:
+ """Parse passes.def, gathering a list of pass class names"""
+ def __init__(self):
+ srcdir = find_gcc_source_dir()
+ self.names = []
+ with open(os.path.join(srcdir, 'passes.def')) as f:
+ for line in f:
+ m = re.match('\s*NEXT_PASS \(([^,]+).*\);', line)
+ if m:
+ self.names.append(m.group(1))
+
+class BreakOnPass(gdb.Command):
+ """
+ A custom command for putting breakpoints on the execute hook of passes.
+ This is largely a workaround for issues with tab-completion in gdb when
+ setting breakpoints on methods on classes within anonymous namespaces.
+
+ Example of use: putting a breakpoint on "final"
+ (gdb) break-on-pass
+ Press <TAB>; it autocompletes to "pass_":
+ (gdb) break-on-pass pass_
+ Press <TAB>:
+ Display all 219 possibilities? (y or n)
+ Press "n"; then type "f":
+ (gdb) break-on-pass pass_f
+ Press <TAB> to autocomplete to pass classnames beginning with "pass_f":
+ pass_fast_rtl_dce pass_fold_builtins
+ pass_feedback_split_functions pass_forwprop
+ pass_final pass_fre
+ pass_fixup_cfg pass_free_cfg
+ Type "in<TAB>" to complete to "pass_final":
+ (gdb) break-on-pass pass_final
+ ...and hit <RETURN>:
+ Breakpoint 6 at 0x8396ba: file ../../src/gcc/final.c, line 4526.
+ ...and we have a breakpoint set; continue execution:
+ (gdb) cont
+ Continuing.
+ Breakpoint 6, (anonymous namespace)::pass_final::execute (this=0x17fb990) at ../../src/gcc/final.c:4526
+ 4526 virtual unsigned int execute (function *) { return rest_of_handle_final (); }
+ """
+ def __init__(self):
+ gdb.Command.__init__(self, 'break-on-pass', gdb.COMMAND_BREAKPOINTS)
+ self.pass_names = None
+
+ def complete(self, text, word):
+ # Lazily load pass names:
+ if not self.pass_names:
+ self.pass_names = PassNames()
+
+ return [name
+ for name in sorted(self.pass_names.names)
+ if name.startswith(text)]
+
+ def invoke(self, arg, from_tty):
+ sym = '(anonymous namespace)::%s::execute' % arg
+ breakpoint = gdb.Breakpoint(sym)
+
+BreakOnPass()
+
+class DumpFn(gdb.Command):
+ """
+ A custom command to dump a gimple/rtl function to file. By default, it
+ dumps the current function using 0 as dump_flags, but the function and flags
+ can also be specified. If /f <file> are passed as the first two arguments,
+ the dump is written to that file. Otherwise, a temporary file is created
+ and opened in the text editor specified in the EDITOR environment variable.
+
+ Examples of use:
+ (gdb) dump-fn
+ (gdb) dump-fn /f foo.1.txt
+ (gdb) dump-fn cfun->decl
+ (gdb) dump-fn /f foo.1.txt cfun->decl
+ (gdb) dump-fn cfun->decl 0
+ (gdb) dump-fn cfun->decl dump_flags
+ """
+
+ def __init__(self):
+ gdb.Command.__init__(self, 'dump-fn', gdb.COMMAND_USER)
+
+ def invoke(self, arg, from_tty):
+ # Parse args, check number of args
+ args = gdb.string_to_argv(arg)
+ if len(args) >= 1 and args[0] == "/f":
+ if len(args) == 1:
+ print ("Missing file argument")
+ return
+ filename = args[1]
+ editor_mode = False
+ base_arg = 2
+ else:
+ editor = os.getenv("EDITOR", "")
+ if editor == "":
+ print ("EDITOR environment variable not defined")
+ return
+ editor_mode = True
+ base_arg = 0
+ if len(args) - base_arg > 2:
+ print ("Too many arguments")
+ return
+
+ # Set func
+ if len(args) - base_arg >= 1:
+ funcname = args[base_arg]
+ printfuncname = "function %s" % funcname
+ else:
+ funcname = "cfun ? cfun->decl : current_function_decl"
+ printfuncname = "current function"
+ func = gdb.parse_and_eval(funcname)
+ if func == 0:
+ print ("Could not find %s" % printfuncname)
+ return
+ func = "(tree)%u" % func
+
+ # Set flags
+ if len(args) - base_arg >= 2:
+ flags = gdb.parse_and_eval(args[base_arg + 1])
+ else:
+ flags = 0
+
+ # Get tempory file, if necessary
+ if editor_mode:
+ f = tempfile.NamedTemporaryFile(delete=False, suffix=".txt")
+ filename = f.name
+ f.close()
+
+ # Open file
+ fp = gdb.parse_and_eval("(FILE *) fopen (\"%s\", \"w\")" % filename)
+ if fp == 0:
+ print ("Could not open file: %s" % filename)
+ return
+
+ # 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("(int) fclose (%s)" % fp)
+ if ret != 0:
+ print ("Could not close file: %s" % filename)
+ return
+
+ # Open file in editor, if necessary
+ if editor_mode:
+ os.system("( %s \"%s\"; rm \"%s\" ) &" %
+ (editor, filename, filename))
+
+DumpFn()
+
+class DotFn(gdb.Command):
+ """
+ A custom command to show a gimple/rtl function control flow graph.
+ By default, it show the current function, but the function can also be
+ specified.
+
+ Examples of use:
+ (gdb) dot-fn
+ (gdb) dot-fn cfun
+ (gdb) dot-fn cfun 0
+ (gdb) dot-fn cfun dump_flags
+ """
+ def __init__(self):
+ gdb.Command.__init__(self, 'dot-fn', gdb.COMMAND_USER)
+
+ def invoke(self, arg, from_tty):
+ # Parse args, check number of args
+ args = gdb.string_to_argv(arg)
+ if len(args) > 2:
+ print("Too many arguments")
+ return
+
+ # Set func
+ if len(args) >= 1:
+ funcname = args[0]
+ printfuncname = "function %s" % funcname
+ else:
+ funcname = "cfun"
+ printfuncname = "current function"
+ func = gdb.parse_and_eval(funcname)
+ if func == 0:
+ print("Could not find %s" % printfuncname)
+ return
+ func = "(struct function *)%s" % func
+
+ # Set flags
+ if len(args) >= 2:
+ flags = gdb.parse_and_eval(args[1])
+ else:
+ flags = 0
+
+ # Get temp file
+ f = tempfile.NamedTemporaryFile(delete=False)
+ filename = f.name
+
+ # Close and reopen temp file to get C FILE*
+ f.close()
+ fp = gdb.parse_and_eval("(FILE *) fopen (\"%s\", \"w\")" % filename)
+ if fp == 0:
+ print("Cannot open temp file")
+ return
+
+ # Write graph to temp file
+ _ = gdb.parse_and_eval("start_graph_dump (%s, \"<debug>\")" % fp)
+ _ = gdb.parse_and_eval("print_graph_cfg (%s, %s, %u)"
+ % (fp, func, flags))
+ _ = gdb.parse_and_eval("end_graph_dump (%s)" % fp)
+
+ # Close temp file
+ ret = gdb.parse_and_eval("(int) fclose (%s)" % fp)
+ if ret != 0:
+ print("Could not close temp file: %s" % filename)
+ return
+
+ # Show graph in temp file
+ os.system("( dot -Tx11 \"%s\"; rm \"%s\" ) &" % (filename, filename))
+
+DotFn()
print('Successfully loaded GDB hooks for GCC')