Provide dis.Bytecode based equivalent of dis.distb #62116
Description
| BPO | 17916 |
|---|---|
| Nosy | @ncoghlan, @PCManticore |
| Dependencies | |
| Files |
Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.
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GitHub fields:
assignee = 'https://github.com/ncoghlan'
closed_at = <Date 2013-11-22.14:57:23.524>
created_at = <Date 2013-05-06.12:54:24.115>
labels = ['type-feature']
title = 'Provide dis.Bytecode based equivalent of dis.distb'
updated_at = <Date 2013-11-22.14:58:24.766>
user = 'https://github.com/ncoghlan'bugs.python.org fields:
activity = <Date 2013-11-22.14:58:24.766>
actor = 'ncoghlan'
assignee = 'ncoghlan'
closed = True
closed_date = <Date 2013-11-22.14:57:23.524>
closer = 'python-dev'
components = []
creation = <Date 2013-05-06.12:54:24.115>
creator = 'ncoghlan'
dependencies = ['11816', '19378']
files = ['31399', '32333', '32762']
hgrepos = []
issue_num = 17916
keywords = ['patch']
message_count = 10.0
messages = ['188528', '195776', '201124', '201133', '201160', '203619', '203623', '203671', '203775', '203776']
nosy_count = 3.0
nosy_names = ['ncoghlan', 'Claudiu.Popa', 'python-dev']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue17916'
versions = ['Python 3.4']
Activity
ncoghlan commentedon May 6, 2013
bpo-11816 adds a new dis.Bytecode API that replaces most of the dis functions, but doesn't cover dis.distb.
A dis.Bytecode.from_tb class method, or a TracebackBytecode subclass to handle that use case may be desirable.
PCManticore commentedon Aug 21, 2013
Here's a basic patch, using a classmethod. It doesn't support the full distb API (if the traceback is not given, try to retrieve the last one), because Bytecode.from_tb() looks pretty weird.
PCManticore commentedon Oct 24, 2013
Nick, could you review this, please? It would be nice if we can flesh it out and add it to 3.4.
ncoghlan commentedon Oct 24, 2013
It's not quite that simple - the instruction responsible for the exception also needs to be recorded, and Bytecode doesn't currently allow for that (look at the way the "lasti" arg to disassemble is used in disttb, and then how that gets passed to the "mark_as_current" flag in Instruction._disassemble by _disassemble_bytes).
So, on reflection, I think a TracebackBytecode class may be a better idea, exposing "bytecode" and "last_offset" attributes.
Rather than iteration just producing instructions, it would produce (instruction, is_current) 2-tuples, and display_code would call through to "self.bytecode.display_code(self.last_offset)" (there would be no show_info() or info() methods on TracebackBytecode).
Bytecode.display_code would gain a new "current_offset" parameter, which it would pass through to _disassemble_bytes as the "lasti" parameter.
Reviewing this also made me realise "line_offset" in dis.get_instructions is misnamed - see bpo-19378.
PCManticore commentedon Oct 24, 2013
Here's the updated version according to your comments. Because there is no need for show_info() and info(), the current class is not a subclass of Bytecode (as I implied from your first message). After bpo-19378 is fixed, we could change the line_offset with something else in TracebackBytecode.__iter__.
PCManticore commentedon Nov 21, 2013
Nick, what's your opinion on my latest patch?
ncoghlan commentedon Nov 21, 2013
My apologies for not reviewing this earlier, it's been a somewhat hectic month. Thanks for pinging the ticket while there's still a chance to get this into 3.4 :)
After my last round of updates to dis.Bytecode removed the potential for confusion between line_offset and current_offset, I'm back to thinking it makes more sense to build this feature directly into dis.Bytecode rather than using a separate type.
PCManticore commentedon Nov 21, 2013
Thanks, Nick! Attached the new version, I hope that I did it right this time.
python-dev commentedon Nov 22, 2013
New changeset d71251d9fbbe by Nick Coghlan in branch 'default':
Close bpo-17916: dis.Bytecode based replacement for distb
http://hg.python.org/cpython/rev/d71251d9fbbe
ncoghlan commentedon Nov 22, 2013
Thank you for the patch! It's nice to have this included for the initial general availability of the new disassembly API :)