[68]l: generate debug info for builtin structured types. prettyprinting in gdb.
R=rsc
CC=golang-dev
https://golang.org/cl/3309041
diff --git a/src/pkg/runtime/runtime-gdb.py b/src/pkg/runtime/runtime-gdb.py
new file mode 100644
index 0000000..422809e
--- /dev/null
+++ b/src/pkg/runtime/runtime-gdb.py
@@ -0,0 +1,174 @@
+# Copyright 2010 The Go Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+"""GDB Pretty printers and convencience functions for Go's runtime structures.
+
+This script is loaded by GDB when it finds a .debug_gdb_scripts
+section in the compiled binary. The [68]l linkers emit this with a
+path to this file based on the path to the runtime package.
+"""
+
+import sys, re
+
+print >>sys.stderr, "Loading Go Runtime support."
+
+#
+# Pretty Printers
+#
+
+class StringTypePrinter:
+ "Pretty print Go strings."
+
+ pattern = re.compile(r'^struct string$')
+
+ def __init__(self, val):
+ self.val = val
+
+ def display_hint(self):
+ return 'string'
+
+ def to_string(self):
+ return self.val['str']
+
+
+class SliceTypePrinter:
+ "Pretty print slices."
+
+ pattern = re.compile(r'^struct \[\]')
+
+ def __init__(self, val):
+ self.val = val
+
+ def display_hint(self):
+ return 'array'
+
+ def to_string(self):
+ return str(self.val.type)[6:] # skip 'struct '
+
+ def children(self):
+ ptr = self.val["array"]
+ for idx in range(self.val["len"]):
+ yield ('[%d]' % idx, (ptr + idx).dereference())
+
+
+class MapTypePrinter:
+ """Pretty print map[K]V types.
+
+ Map-typed go variables are really pointers. dereference them in gdb
+ to inspect their contents with this pretty printer.
+ """
+
+ pattern = re.compile(r'^struct hash<.*>$')
+
+ def __init__(self, val):
+ self.val = val
+
+ def display_hint(self):
+ return 'map'
+
+ def to_string(self):
+ return str(self.val.type)
+
+ def children(self):
+ stab = self.val['st']
+ i = 0
+ for v in self.traverse_hash(stab):
+ yield ("[%d]" % i, v['key'])
+ yield ("[%d]" % (i + 1), v['val'])
+ i += 2
+
+ def traverse_hash(self, stab):
+ ptr = stab['entry'].address
+ end = stab['end']
+ while ptr < end:
+ v = ptr.dereference()
+ ptr = ptr + 1
+ if v['hash'] == 0: continue
+ if v['hash'] & 63 == 63: # subtable
+ for v in self.traverse_hash(v['key'].cast(self.val['st'].type)):
+ yield v
+ else:
+ yield v
+
+
+class ChanTypePrinter:
+ """Pretty print chan[T] types.
+
+ Map-typed go variables are really pointers. dereference them in gdb
+ to inspect their contents with this pretty printer.
+ """
+
+ pattern = re.compile(r'^struct hchan<.*>$')
+
+ def __init__(self, val):
+ self.val = val
+
+ def display_hint(self):
+ return 'array'
+
+ def to_string(self):
+ return str(self.val.type)
+
+ def children(self):
+ ptr = self.val['recvdataq']
+ for idx in range(self.val["qcount"]):
+ yield ('[%d]' % idx, ptr['elem'])
+ ptr = ptr['link']
+
+#
+# Register all the *Printer classes
+#
+
+def makematcher(klass):
+ def matcher(val):
+ try:
+ if klass.pattern.match(str(val.type)): return klass(val)
+ except: pass
+ return matcher
+
+gdb.current_objfile().pretty_printers.extend([makematcher(k) for k in vars().values() if hasattr(k, 'pattern')])
+
+
+#
+# Convenience Functions
+#
+
+class GoLenFunc(gdb.Function):
+ "Length of strings, slices, maps or channels"
+
+ how = ((StringTypePrinter, 'len' ),
+ (SliceTypePrinter, 'len'),
+ (MapTypePrinter, 'count'),
+ (ChanTypePrinter, 'qcount'))
+
+ def __init__(self):
+ super(GoLenFunc, self).__init__("len")
+
+ def invoke(self, obj):
+ typename = str(obj.type)
+ for klass, fld in self.how:
+ if klass.pattern.match(typename):
+ return obj[fld]
+
+class GoCapFunc(gdb.Function):
+ "Capacity of slices or channels"
+
+ how = ((SliceTypePrinter, 'cap'),
+ (ChanTypePrinter, 'dataqsiz'))
+
+ def __init__(self):
+ super(GoCapFunc, self).__init__("cap")
+
+ def invoke(self, obj):
+ typename = str(obj.type)
+ for klass, fld in self.how:
+ if klass.pattern.match(typename):
+ return obj[fld]
+
+#
+# Register all convience functions and CLI commands
+#
+for k in vars().values():
+ if hasattr(k, 'invoke'):
+ k()
