js/src/gdb/mozilla/Root.py@a63d609f5ebe (annotated)
js/src/gdb/mozilla/Root.py
Thu, 15 Jan 2015 15:55:04 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Thu, 15 Jan 2015 15:55:04 +0100
- branch
- TOR_BUG_9701
- changeset 9
- a63d609f5ebe
- permissions
- -rw-r--r--
Back out 97036ab72558 which inappropriately compared turds to third parties.
| michael@0 | 1 | # Pretty-printers and utilities for SpiderMonkey rooting templates: |
| michael@0 | 2 | # Rooted, Handle, MutableHandle, etc. |
| michael@0 | 3 | |
| michael@0 | 4 | import mozilla.prettyprinters |
| michael@0 | 5 | from mozilla.prettyprinters import pretty_printer, template_pretty_printer |
| michael@0 | 6 | |
| michael@0 | 7 | # Forget any printers from previous loads of this module. |
| michael@0 | 8 | mozilla.prettyprinters.clear_module_printers(__name__) |
| michael@0 | 9 | |
| michael@0 | 10 | # Common base class for all the rooting template pretty-printers. All these |
| michael@0 | 11 | # templates have one member holding the referent (or a pointer to it), so |
| michael@0 | 12 | # there's not much to it. |
| michael@0 | 13 | class Common(object): |
| michael@0 | 14 | # The name of the template member holding the referent. |
| michael@0 | 15 | member = 'ptr' |
| michael@0 | 16 | |
| michael@0 | 17 | # If True, this is a handle type, and should be dereferenced. If False, |
| michael@0 | 18 | # the template member holds the referent directly. |
| michael@0 | 19 | handle = False |
| michael@0 | 20 | |
| michael@0 | 21 | # Initialize a pretty-printer for |value|, using |cache|. |
| michael@0 | 22 | # |
| michael@0 | 23 | # If given, |content_printer| is a pretty-printer constructor to use for |
| michael@0 | 24 | # this handle/root/etc.'s referent. Usually, we can just omit this argument |
| michael@0 | 25 | # and let GDB choose a pretty-printer for the referent given its type, but |
| michael@0 | 26 | # when the referent is a typedef of an integral type (say, |jsid| in a |
| michael@0 | 27 | # non-|DEBUG| build), the GNU toolchain (at least) loses the typedef name, |
| michael@0 | 28 | # and all we know about the referent is its fundamental integer type --- |
| michael@0 | 29 | # |JS::Rooted<jsid>|, for example, appears in GDB as |JS::Rooted<long>| --- |
| michael@0 | 30 | # and we are left with no way to choose a meaningful pretty-printer based on |
| michael@0 | 31 | # the type of the referent alone. However, because we know that the only |
| michael@0 | 32 | # integer type for which |JS::Rooted| is likely to be instantiated is |
| michael@0 | 33 | # |jsid|, we *can* register a pretty-printer constructor for the full |
| michael@0 | 34 | # instantiation |JS::Rooted<long>|. That constructor creates a |JS::Rooted| |
| michael@0 | 35 | # pretty-printer, and explicitly specifies the constructor for the referent, |
| michael@0 | 36 | # using this initializer's |content_printer| argument. |
| michael@0 | 37 | def __init__(self, value, cache, content_printer=None): |
| michael@0 | 38 | self.value = value |
| michael@0 | 39 | self.cache = cache |
| michael@0 | 40 | self.content_printer = content_printer |
| michael@0 | 41 | def to_string(self): |
| michael@0 | 42 | ptr = self.value[self.member] |
| michael@0 | 43 | if self.handle: |
| michael@0 | 44 | ptr = ptr.dereference() |
| michael@0 | 45 | if self.content_printer: |
| michael@0 | 46 | return self.content_printer(ptr, self.cache).to_string() |
| michael@0 | 47 | else: |
| michael@0 | 48 | # As of 2012-11, GDB suppresses printing pointers in replacement |
| michael@0 | 49 | # values; see http://sourceware.org/ml/gdb/2012-11/msg00055.html |
| michael@0 | 50 | # That means that simply returning the 'ptr' member won't work. |
| michael@0 | 51 | # Instead, just invoke GDB's formatter ourselves. |
| michael@0 | 52 | return str(ptr) |
| michael@0 | 53 | |
| michael@0 | 54 | @template_pretty_printer("JS::Rooted") |
| michael@0 | 55 | class Rooted(Common): |
| michael@0 | 56 | pass |
| michael@0 | 57 | |
| michael@0 | 58 | @template_pretty_printer("JS::Handle") |
| michael@0 | 59 | class Handle(Common): |
| michael@0 | 60 | handle = True |
| michael@0 | 61 | |
| michael@0 | 62 | @template_pretty_printer("JS::MutableHandle") |
| michael@0 | 63 | class MutableHandle(Common): |
| michael@0 | 64 | handle = True |
| michael@0 | 65 | |
| michael@0 | 66 | @template_pretty_printer("js::EncapsulatedPtr") |
| michael@0 | 67 | class EncapsulatedPtr(Common): |
| michael@0 | 68 | member = 'value' |
| michael@0 | 69 | |
| michael@0 | 70 | @pretty_printer("js::EncapsulatedValue") |
| michael@0 | 71 | class EncapsulatedValue(Common): |
| michael@0 | 72 | member = 'value' |
| michael@0 | 73 | |
| michael@0 | 74 | @pretty_printer("js::BarrieredValue") |
| michael@0 | 75 | class BarrieredValue(Common): |
| michael@0 | 76 | member = 'value' |
| michael@0 | 77 | |
| michael@0 | 78 | # Return the referent of a HeapPtr, Rooted, or Handle. |
| michael@0 | 79 | def deref(root): |
| michael@0 | 80 | tag = root.type.strip_typedefs().tag |
| michael@0 | 81 | if not tag: |
| michael@0 | 82 | raise TypeError("Can't dereference type with no structure tag: %s" % (root.type,)) |
| michael@0 | 83 | elif tag.startswith('js::HeapPtr<'): |
| michael@0 | 84 | return root['value'] |
| michael@0 | 85 | elif tag.startswith('JS::Rooted<'): |
| michael@0 | 86 | return root['ptr'] |
| michael@0 | 87 | elif tag.startswith('JS::Handle<'): |
| michael@0 | 88 | return root['ptr'] |
| michael@0 | 89 | else: |
| michael@0 | 90 | raise NotImplementedError |
