🚀 Bytecode VM by timfennis · Pull Request #93 · timfennis/andy-cpp

timfennis · 2026-03-08T07:25:24Z

Summary

Replaces the tree-walk interpreter with a bytecode-compiled stack-based VM as the single execution path (~192 commits).

Compiler & VM

Bytecode compiler translates the annotated AST into a flat OpCode sequence
Stack-based VM executes bytecode with support for locals, globals, upvalues, and closures
Upvalue hoisting in the analyser enables mutable closed-over variables
Control flow: if/while/for/break/continue/return all compile to jump instructions
Tuple destructuring via Unpack opcode
Map/set/list comprehensions compile to inline loops
Op-assignment (+=, etc.) for identifiers, index expressions, and destructuring
Closure capture and upvalue resolution (including nested closures)
Memoization support for pure functions

Stdlib & dispatch

FunctionRegistry + vm_native field on Function for bridge-free native dispatch
Arithmetic, comparison, boolean, trig/math operators migrated to VM-native dispatch
HOF callbacks (map, filter, fold, all, any, etc.) work with VM closures
Dynamic dispatch for overloaded functions at runtime

Infrastructure

ndc_vm crate with compiler and VM
vm-trace feature for source-annotated instruction tracing
-disassemble` CLI subcommand
All existing tests pass against the VM backend

Benchmarks (v0.2.1 tree-walk vs VM)

Benchmark	v0.2.1 (tree-walk)	VM	Speedup
ackermann	stack overflow	155.0 ms	-
bigint	9.3 ms	6.7 ms	1.4x
closures	248.5 ms	78.6 ms	3.2x
fibonacci	318.0 ms	80.1 ms	4.0x
hof_pipeline	84.8 ms	36.7 ms	2.3x
map_ops	74.7 ms	28.7 ms	2.6x
matrix_mul	133.1 ms	67.0 ms	2.0x
perlin	216.5 ms	67.5 ms	3.2x
pi_approx	103.8 ms	32.3 ms	3.2x
print_heavy	8.9 ms	5.6 ms	1.6x
quicksort	192.0 ms	75.2 ms	2.6x
sieve	439.4 ms	125.2 ms	3.5x
string_concat	16.0 ms	13.4 ms	1.2x

🤖 Generated with Claude Code

…pressions

…layout - Parser: stop wrapping VariableDeclaration in Statement; add it to is_valid_statement so the parse loop continues - Compiler: split VariableDeclaration (push value only) from Assignment (push value + SetLocal + push unit); remove TODO comment - VM: start with empty stack instead of pushing the script function, fixing local slot 0 conflicts that corrupted all local variables - Tests: add test_declaration and test_assignment compiler tests

…rning

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

- M1: extract compile_for_iterations helper, removing ~120 lines of duplicated loop scaffolding - M2: make VmIterator::deep_copy a required method; add missing impls for MinHeapIter, MaxHeapIter, StringIter - RD1: comment explaining synthetic unit push in no-else branch - RD2: remove dead `let memo =` binding in dispatch_call - RD3: descriptive panic messages in Closure opcode handling - RD4: rename max_local field to num_locals (matching its accessor) - Remove REVIEW.md (all actionable items resolved) Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

…() builtin Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

…ly-qualified Value paths - Rename match.rs → types.rs with unified NdcType enum and classify() function - Replace panics with syn::Error for proper compiler diagnostics - Remove dead #[function] stub, add arg_error() and refcell_collection_arg() helpers - Add module-level documentation to all macro crate files - Update stdlib to use short Value/Object/SeqValue/MapValue imports everywhere Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

…n hot paths - Merge MinHeapIter/MaxHeapIter into single HeapIter - Merge List/Tuple unpack branches in VM - Combine RangeInclusive/RangeExclusive compiler arms - Inline vectorization_pairs into try_vectorized_call - Use &OpCode references in Chunk::iter() and disassembler - Cache Value::unit() via thread_local (9-16% faster on benchmarks) - Minor: fix parens, rename shadowed param, update ndc_macros for HeapIter Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

…resolvers Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

…inition error - Upvalues no longer short-circuit resolution: the scope walk continues to find exact matches for other overloads in parent scopes - add_upvalue deduplicates by name+source so multiple overloads of the same function get separate upvalue entries - Same-scope same-arity fn redefinition is now a compile error - 9 new tests for shadowing/overloading semantics - Updated manual with shadowing documentation Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Function resolution now filters out bindings with known non-callable types (Int, String, etc.) from the dynamic fallback, turning confusing runtime errors into compile-time errors. Also tracks explicit `return` types via a stack so `return value;` correctly infers the function's return type instead of unit. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

… Any return/break/continue now produce Never (bottom type) instead of unit. Statement propagates Never so blocks see that control doesn't fall through. This prevents `return 1;` from polluting the function's return type with unit via lub. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

… upvalues Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

timfennis changed the title ~~Feature/bytecode vm~~ 🚀 Bytecode VM Mar 10, 2026

timfennis marked this pull request as ready for review March 21, 2026 20:11

timfennis added 28 commits March 21, 2026 21:19

✨ Add ndc_vm crate skeleton for bytecode VM

e692dc3

📚 Chapter 14 + 15

9927b52

🚧 WIP bytecode VM compiler and chunk

5d5377d

New Value type for the VM, and constant compilation

4abee12

WIP

4df1fa1

Fix warnings

9165783

Basic conditions implemented

ef9dcf1

Make function definition expression contain a signature instead of ex…

044efc3

…pressions

Add tests for the compiler output

e162ea3

Add disassembling functionality

77fc8c4

🌍 Add GetGlobal opcode and wire up Call instruction in the VM

2760d43

🔧 Bridge stdlib globals into VM and fix locals to use the stack

6f878d9

🔀 Add runtime dynamic dispatch for overloaded functions in the VM

ed4c9df

Fix compilation of return opcodes

beb98c3

✅ Fix Statement/Block compilation and add compiler tests

b11186e

♻️ Add Value::unit() constructor and use it in the compiler

4fc75bd

♻️ Extract dispatch_call to remove duplicated Call logic

87b3178

✅ Run tests against both tree-walk and VM interpreter

2968da1

🔌 Wire VM print output to the interpreter's captured buffer

e6c1571

🔍 Add vm-trace feature for source-annotated instruction tracing

95219b6

💥 Add todo!() panics for unimplemented compiler branches

5624eeb

🧹 Move vm-trace ip capture inside cfg block, suppress unused param wa…

b5c90b0

…rning

Benchmark tool + tuple and list support

3b046b8

⚡ Pre-allocate stack and avoid to_vec() on native calls

8513531

Upvalue WIP + cargo fmt

1338322

🔒 Implement closure capture and upvalue resolution in the VM

ab5d717

📦 Make VM lists reference-counted and sync mutations through the bridge

bbb0e6d

timfennis and others added 26 commits March 21, 2026 21:19

Fix: B6 — resolve_callee returns VmError instead of panicking

b76bea1

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Fix: analyser rejects calling non-function types

5017a9c

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Refactor: R5 — remove RefCell from VmCallable

26f0f33

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Add documentation to all manually registered stdlib functions

f90dc38

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Add docs to all undocumented stdlib functions, fix spelling, add docs…

d16a50f

…() builtin Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Remove obsolete design documents

e7586c0

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Collect TODOs into TODO.md, remove from source, add CLAUDE.md rule

3fadf31

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Add ndc_analyser code review notes

70b35ab

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Deduplicate ndc_analyser: scope-walk helpers, fold_lub, merge lvalue …

7478585

…resolvers Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Small cleanups in ndc_analyser: unreachable!, stale comments, docs

ccdc179

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Merge triple scope walk into single-pass resolve_function_binding

be2d57d

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Pass actual types when resolving index operators [] and []=

ed1344d

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

⚡ Skip close_upvalues when no open upvalues; use Vec::new() for empty…

dea95fc

… upvalues Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

📝 Improve README examples

349f326

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Convert accumulator_slot .expect() panics to CompileErrors

faaace5

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Convert ListPush and MapInsert panics to VmErrors

db792e4

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Embed git commit hash in --version output

adac20d

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Add memory management page to manual

a641c66

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

📎 clippy fixes

5361ec6

📎 Fix all clippy warnings, add &mut [T] macro support

5b1cd6d

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

timfennis force-pushed the feature/bytecode-vm branch from 1015041 to 5b1cd6d Compare March 21, 2026 20:19

timfennis enabled auto-merge (squash) March 21, 2026 20:20

timfennis merged commit e9a5365 into master Mar 21, 2026
1 check passed

timfennis deleted the feature/bytecode-vm branch March 21, 2026 20:21

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🚀 Bytecode VM#93

🚀 Bytecode VM#93
timfennis merged 193 commits intomasterfrom
feature/bytecode-vm

timfennis commented Mar 8, 2026 •

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Summary

Compiler & VM

Stdlib & dispatch

Infrastructure

Benchmarks (v0.2.1 tree-walk vs VM)

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timfennis commented Mar 8, 2026 •

edited

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