Description

markshannon

opened on Aug 20, 2024

Issue body actions

Feature or enhancement

Proposal:

dis.dis is a useful debugging tool when trying to debug minor bytecode compiler errors.
However it lacks one important feature, the ability to see the exact positions attached to instructions. It can only show line numbers.

We should add a show_positions keyword argument to show positions.
For example, the function:

def foo(x):
    if x == 2:
        return 1

disassembles to:

  2           RESUME                   0

  3           LOAD_FAST                0 (x)
              LOAD_CONST               1 (2)
              COMPARE_OP              88 (bool(==))
              POP_JUMP_IF_FALSE        1 (to L1)

  4           RETURN_CONST             2 (1)

  3   L1:     RETURN_CONST             0 (None)

with show_positions it would disassemble to something like:

2:0-2:0                RESUME                   0

3:7-3:8                LOAD_FAST                0 (x)
3:12-3:13              LOAD_CONST               1 (2)
3:7-3:13               COMPARE_OP              88 (bool(==))
3:7-3:13               POP_JUMP_IF_FALSE        1 (to L1)

4:15-4:16              RETURN_CONST             2 (1)

3:7-3:13       L1:     RETURN_CONST             0 (None)

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

No response

Linked PRs

• gh-123165: make dis functions render positions on demand #123168
• gh-123165: correct tests for dis.dis(func, show_positions=True) #123220
• gh-123165: improve docs signature for dis.disassemble #123808

Activity

1. markshannon

   added

   type-featureA feature request or enhancementA feature request or enhancement

   on Aug 20, 2024
2. markshannon commented on Aug 20, 2024

   

   markshannon

   on Aug 20, 2024

   MemberAuthor

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   @iritkatriel
3. iritkatriel

   added

   easy

   stdlibStandard Library Python modules in the Lib/ directoryStandard Library Python modules in the Lib/ directory

   on Aug 20, 2024
4. picnixz commented on Aug 20, 2024

   

   picnixz

   on Aug 20, 2024

   Member

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   Since it's marked as an easy feature, could I perhaps work on this? (I took upon the task of doing it, so it will be ready in a few hours I think)
5. picnixz

   self-assigned this

   on Aug 20, 2024
6. iritkatriel

   added a commit that references this issue on Aug 21, 2024

   gh-123165: make `dis` functions render positions on demand (#123168)

   b1d3bd2
7. iritkatriel

   closed this as completedon Aug 21, 2024
8. blhsing

   added a commit that references this issue on Aug 22, 2024

   pythongh-123165: make `dis` functions render positions on demand (pyt…

   966626a
9. iritkatriel

   added a commit that references this issue on Aug 22, 2024

   gh-123165: correct tests for `dis.dis(func, show_positions=True)` (#1…

   31acc4d
10. iritkatriel

    added a commit that references this issue on Sep 10, 2024

    gh-123165: update docs signature for `dis.disassemble` (#123808)

    07f0bf5

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