Bytecode oparg optimization by ShaharNaveh · Pull Request #7032 · RustPython/RustPython · GitHub

Discussed at #6980 (comment)
Pretty much reverts #6980.

Summary by CodeRabbit

Chores
- Removed unused internal dependency
- Internal code structure improvements and standardization
Refactor
- Simplified internal type conversion patterns across the compiler

📝 Walkthrough

Walkthrough

This PR refactors bytecode enum handling and casting patterns across the compiler. It replaces explicit u32 casts with standard conversion functions (u32::from()), removes the num_enum dependency, adds Debug derives to bytecode types, macro-generates oparg enum definitions and trait implementations, and removes const qualifiers from eval_ord methods. All changes maintain functional equivalence while modernizing the codebase.

Changes

Cohort / File(s)	Summary
Casting & Conversion Modernization crates/codegen/src/compile.rs, crates/vm/src/types/slot.rs	Updated explicit u32 and u8 casts to use u32::from() and u8::from() for ResumeType and comparison operators. In compile.rs, also adjusted oparg calculation for BUILD_INTERPOLATION. Removed const qualifier from eval_ord methods in slot.rs.
Bytecode Debug Support crates/compiler-core/src/bytecode.rs	Added Debug derive to CodeUnit and CodeUnits structs to enable debug formatting alongside existing Copy/Clone and Clone derives respectively.
Enum Macro Refactoring crates/compiler-core/src/bytecode/oparg.rs	Introduced oparg_enum! and impl_oparg_enum macros to auto-generate TryFrom, From, and OpArgType trait implementations. Refactored all public enums (ConvertValueOparg, ResumeType, RaiseKind, IntrinsicFunction1/2, Intrinsic, BinaryOperator, ComparisonOperator, Invert, SpecialMethod, CommonConstant, BuildSliceArgCount) to use macro-based definitions, eliminating repetitive manual trait impls.
Dependency Cleanup crates/compiler-core/Cargo.toml	Removed workspace dependency on num_enum from [dependencies] section.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~22 minutes

Possibly related PRs

Instruction::Resume #5944: Directly related through compile.rs ResumeType cast updates that align with Resume instruction introduction and ResumeType handling.
Use num_enum crate for oparg types #6980: Connected via oparg enum representation changes and conversion code refactoring; both touch ResumeType and num_enum-related conversions.
Update opcode, dis from 3.14.2 #6869: Related through resume emission logic modifications in compile.rs where ResumeType-to-u32 conversions are adjusted.

Suggested reviewers

youknowone

Poem

🐰 Hoppy hops through casting code,
Macros bloom along the road!
Enums dance in templates bright,
From-conversions feel so right! ✨
Debug fields now shine with care,
Refactored with rabbit flair!

🚥 Pre-merge checks | ✅ 3 ✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'Bytecode oparg optimization' directly and accurately reflects the main objective of the PR: optimizing bytecode operand arguments through macro-based enum generation and the removal of the num_enum dependency.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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✨ Finishing touches

📝 Generate docstrings

🧪 Generate unit tests (beta)

Create PR with unit tests
Post copyable unit tests in a comment

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@youknowone This breaks RustPython. if I put $variant = $value then everything works just fine.
I suspect that there's some unsafe transmuting somewhere, do you have an idea how can I debug this?

After lots of debugging I've figured that the only problematic enum is ComparisonOperator. I'm not sure about why yet, but it's not related to an unsafe transmutation like I initially thought

ComparisonOperator seems to support bit operation. It doesn't have 0 like other enums

…mization

ShaharNaveh added 5 commits February 6, 2026 12:11

Generate optimized oparg enums

deefe91

No need to match on 255

b7794a5

Remove num_enum crate from compiler-core

ebabd58

Update Cargo.lock

a8b581c

macro fmt

e48fdeb

ShaharNaveh added 6 commits February 6, 2026 12:55

Rename macro vars

badcd5f

Match without ,

56e23ef

Support alternative values

5f3eb51

Fix alternatives

a371d16

Improve docs

1035006

Add const assert

14f3030

ShaharNaveh commented Feb 6, 2026

View reviewed changes

ShaharNaveh added 8 commits February 6, 2026 18:20

Don't use as u32

d2c98f0

Merge remote-tracking branch 'upstream/main' into bytecode-oparg-opti…

e3b9efa

…mization

Make only ComparisonOperator unoptimized

4fcc241

Fix test

4a06d52

cleanup

2a9ef82

Merge remote-tracking branch 'upstream/main' into bytecode-oparg-opti…

71be956

…mization

All opargs are optimized

bb5677c

Remove comment

9795123

ShaharNaveh marked this pull request as ready for review February 7, 2026 07:00

ShaharNaveh requested a review from youknowone February 7, 2026 07:59

youknowone approved these changes Feb 7, 2026

View reviewed changes

youknowone enabled auto-merge (squash) February 7, 2026 10:11

youknowone disabled auto-merge February 7, 2026 10:14

youknowone merged commit f817ab8 into RustPython:main Feb 7, 2026
13 checks passed

coderabbitai Bot mentioned this pull request Feb 8, 2026

Make inner oparg values private #7050

Merged

This was referenced Mar 19, 2026

Resume opcode to hold ResumeType #7465

Merged

marshal #7467

Merged

This was referenced Mar 24, 2026

#[newtype_oparg] derive macro #7489

Closed

Oparg resume depth #7515

Merged

+                      $vis enum $name {
+                          $(
+                              $(#[$variant_meta])*
+                              $variant, // Do assign value to variant.

Bytecode oparg optimization by ShaharNaveh · Pull Request #7032 · RustPython/RustPython · GitHub

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Bytecode oparg optimization - #7032

Bytecode oparg optimization#7032
youknowone merged 19 commits into
RustPython:mainfrom
ShaharNaveh:bytecode-oparg-optimization

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Bytecode oparg optimization by ShaharNaveh · Pull Request #7032 · RustPython/RustPython · GitHub

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Bytecode oparg optimization - #7032

Bytecode oparg optimization#7032youknowone merged 19 commits intoRustPython:mainRustPython/RustPython:mainfrom ShaharNaveh:bytecode-oparg-optimizationShaharNaveh/RustPython:bytecode-oparg-optimizationCopy head branch name to clipboard

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Summary by CodeRabbit

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Walkthrough

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Bytecode oparg optimization#7032
youknowone merged 19 commits into
RustPython:mainfrom
ShaharNaveh:bytecode-oparg-optimization

ShaharNaveh commented Feb 6, 2026 •
edited by coderabbitai Bot
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