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jit(wasm): drop the wasm32 arm of the self-recursive root-bridge inline #1106

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Merged
youknowone merged 4 commits into from
Aug 8, 2026
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jit(wasm): drop the wasm32 arm of the self-recursive root-bridge inline #1106

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a62f004
jit(wasm): drop the wasm32 arm of the self-recursive root-bridge inline
youknowone Aug 7, 2026
95ec7f2
jit: decline the `Cls.__name__` fold when its metaclass guard cannot …
youknowone Aug 7, 2026
203cd0c
parity_tests: gate os_utime_pathconf_truncate's POSIX-only halves on …
youknowone Aug 7, 2026
87c0439
jit: read an aborted inline's Ref operand list at its argcode offset
youknowone Aug 7, 2026
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8 changes: 6 additions & 2 deletions pyre/bench/synth/ca_bridge_multiframe_resume_double_call.wasm.jitstats
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Original file line number Diff line number Diff line change
Expand Up @@ -2,9 +2,13 @@ bridges_compiled=16
descr_set_absent=0
descr_set_ambiguous=0
descr_set_stale_absent=0
fbw_blackhole_adopted_multi_frame=0
fbw_blackhole_adopted_single_frame=0
fbw_rolled_back_with_effects=0
fbw_store_journal_rollback_failed=0
guard_failures=2581
field_pos_attached_misplaced=0
field_pos_spec_misplaced=0
guard_failures=2592
internal_compile_panics=0
loops_aborted=1
loops_aborted=0
loops_compiled=3
9 changes: 6 additions & 3 deletions pyre/bench/synth/foriter_call_resume_drops_iteration.wasm.jitstats
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Original file line number Diff line number Diff line change
@@ -1,11 +1,14 @@
bridges_compiled=26
bridges_compiled=27
descr_set_absent=0
descr_set_ambiguous=0
descr_set_stale_absent=0
fbw_blackhole_adopted_multi_frame=0
fbw_blackhole_adopted_single_frame=0
fbw_rolled_back_with_effects=0
fbw_store_journal_rollback_failed=0
field_pos_attached_misplaced=0
field_pos_spec_misplaced=0
guard_failures=5165
guard_failures=5150
internal_compile_panics=0
loops_aborted=2
loops_aborted=1
loops_compiled=3
9 changes: 7 additions & 2 deletions pyre/bench/synth/recursion_memo_branch.wasm.jitstats
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Original file line number Diff line number Diff line change
Expand Up @@ -2,8 +2,13 @@ bridges_compiled=28
descr_set_absent=0
descr_set_ambiguous=0
descr_set_stale_absent=0
fbw_blackhole_adopted_multi_frame=0
fbw_blackhole_adopted_single_frame=0
fbw_rolled_back_with_effects=0
guard_failures=4724
fbw_store_journal_rollback_failed=0
field_pos_attached_misplaced=0
field_pos_spec_misplaced=0
guard_failures=4704
internal_compile_panics=0
loops_aborted=2
loops_aborted=1
loops_compiled=3
14 changes: 14 additions & 0 deletions pyre/bench/synth/selfrec_bridge_nontail_promote.cranelift.jitstats
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@@ -0,0 +1,14 @@
bridges_compiled=6
descr_set_absent=0
descr_set_ambiguous=0
descr_set_stale_absent=0
fbw_blackhole_adopted_multi_frame=0
fbw_blackhole_adopted_single_frame=0
fbw_rolled_back_with_effects=0
fbw_store_journal_rollback_failed=0
field_pos_attached_misplaced=0
field_pos_spec_misplaced=0
guard_failures=806
internal_compile_panics=0
loops_aborted=0
loops_compiled=2
14 changes: 14 additions & 0 deletions pyre/bench/synth/selfrec_bridge_nontail_promote.dynasm.jitstats
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Original file line number Diff line number Diff line change
@@ -0,0 +1,14 @@
bridges_compiled=6
descr_set_absent=0
descr_set_ambiguous=0
descr_set_stale_absent=0
fbw_blackhole_adopted_multi_frame=0
fbw_blackhole_adopted_single_frame=0
fbw_rolled_back_with_effects=0
fbw_store_journal_rollback_failed=0
field_pos_attached_misplaced=0
field_pos_spec_misplaced=0
guard_failures=806
internal_compile_panics=0
loops_aborted=0
loops_compiled=2
38 changes: 38 additions & 0 deletions pyre/bench/synth/selfrec_bridge_nontail_promote.py
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@@ -0,0 +1,38 @@
# pyre-check: max-pypy-ratio=20
# Coverage for the self-recursive root-bridge inline when the recursion is
# non-tail and carries a Ref local.
#
# `walk` is self-recursive, takes exact-integer arguments and holds a
# `BinaryOp` residual, so a guard-failure bridge that reaches its CALL takes the
# root-bridge admission (`bridge_rec_root_selfrec`, inline_call.rs).
# `bridge_recursion_overflow` already covers that admission, but only in its
# easiest form: tail recursion whose live set is two machine integers. Two
# ingredients of the "a Ref reached an int operation" failure it is meant to
# guard against were therefore unexercised.
#
# `acc * 2` crosses the machine-int boundary partway down the recursion, so the
# accumulator promotes to a long — a Ref — at a level that moves with the
# caller's seed, and the overflow guard fires inside the recursive frame. `tag`
# keeps a second Ref live across the recursive CALL beside it, and the non-tail
# `inner + len(tag)` leaves a paused caller chain, so the guard's resume stream
# is multi-frame and mixes Ref with Int rather than being one frame of
# integers.
#
# Byte-parity against CPython/PyPy is the gate: Python integers are unbounded,
# so the promotion must not be observable in the result.
_TAGS = ("a", "bb", "ccc", "dddd")


def walk(n, acc):
if n == 0:
return acc
tag = _TAGS[n & 3]
nxt = acc * 2 + len(tag)
inner = walk(n - 1, nxt)
return inner + len(tag)


out = []
for i in range(50000):
out.append(walk(24, (1 << 50) + i) % 1000000007)

@coderabbitai coderabbitai Bot Aug 7, 2026

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📐 Maintainability & Code Quality | 🟡 Minor | ⚡ Quick win

🧩 Analysis chain

🏁 Script executed:

#!/bin/bash
set -euo pipefail

echo "== files =="
git ls-files | rg 'pyre/bench/synth/selfrec_bridge_nontail_promote\.py|selfrec_bridge_nontail_promote|PERF401|PY'

echo "== target excerpt =="
cat -n pyre/bench/synth/selfrec_bridge_nontail_promote.py

echo "== related jitstats files =="
git ls-files | rg 'selfrec_bridge_nontail_promote'

echo "== ruff config references =="
rg -n "RUFF|ruff|PERF401|PY" -S --glob '!**/.git/**' --glob '!**/*.png' --glob '!**/*.jpg' . | head -200 || true

echo "== git diff stat/name-only =="
git diff --stat || true
git diff --name-only || true

Repository: youknowone/pyre

Length of output: 21136

🌐 Web query:

pyproject.toml ruff PERF401 preferred method build list comprehension

💡 Result:

The Ruff rule PERF401 (manual-list-comprehension) identifies for-loops that can be replaced with a list comprehension or a list extend operation to improve readability and performance [1][2]. The preferred method depends on the context of the code: 1. When initializing a new list: Ruff suggests replacing the loop with a list comprehension [1][3]. Example: # Original filtered = [] for i in original: if i % 2: filtered.append(i) # Preferred (List Comprehension) filtered = [i for i in original if i % 2] 2. When appending to an existing, already populated list: Ruff suggests using the list.extend method with a generator expression [1][4]. Example: # Original existing_list = [1][5] for i in original: if i % 2: existing_list.append(i) # Preferred (list.extend) existing_list.extend(i for i in original if i % 2) Key Considerations: - Purpose: The rule is a micro-optimization [1][2]. While list comprehensions are generally faster (typically 10-25% depending on the Python version), the performance impact is negligible in many real-world scenarios [1][2]. - Limitations: The automatic fix is not always applicable. Ruff applies this rule primarily to simple for-loops (e.g., those with a single non-if statement or a single if statement containing one nested operation) [6][4]. If a loop contains complex logic or multiple operations, it may not trigger the rule [6]. - False Positives: If the logic requires flattening (which.extend does) versus adding elements, or if the loop body is more complex than the rule's simple heuristic can analyze, you should manually evaluate if the suggested transformation maintains correct behavior [4].

Citations:

Resolve Ruff PERF401 without changing the benchmark shape.

This initialization loop triggers PERF401, but converting it to a list(...) construction may change the JIT trace and invalidate the .jitstats baselines. Add a local suppression if the explicit loop is intentional, or regenerate all three selfrec_bridge_nontail_promote JIT-stat files if the comprehension is kept.

Proposed localized suppression 
-    out.append(walk(24, (1 << 50) + i) % 1000000007)
+    out.append(walk(24, (1 << 50) + i) % 1000000007)  # noqa: PERF401
📝 Committable suggestion

‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

Suggested change
out.append(walk(24, (1 << 50) + i) % 1000000007)
out.append(walk(24, (1 << 50) + i) % 1000000007) # noqa: PERF401
🧰 Tools
🪛 Ruff (0.16.1)

[warning] 37-37: Use a list comprehension to create a transformed list

(PERF401)

🤖 Prompt for AI Agents 
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@pyre/bench/synth/selfrec_bridge_nontail_promote.py` at line 37, Preserve the
explicit initialization loop around walk(24, (1 << 50) + i) because the
benchmark shape must remain unchanged, and add a localized Ruff PERF401
suppression to that loop rather than converting it to a comprehension. Keep the
suppression scoped only to this intentional loop.

Source: Linters/SAST tools

print(out[0], out[-1], sum(out) % 1000000007)
14 changes: 14 additions & 0 deletions pyre/bench/synth/selfrec_bridge_nontail_promote.wasm.jitstats
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Original file line number Diff line number Diff line change
@@ -0,0 +1,14 @@
bridges_compiled=6
descr_set_absent=0
descr_set_ambiguous=0
descr_set_stale_absent=0
fbw_blackhole_adopted_multi_frame=0
fbw_blackhole_adopted_single_frame=0
fbw_rolled_back_with_effects=0
fbw_store_journal_rollback_failed=0
field_pos_attached_misplaced=0
field_pos_spec_misplaced=0
guard_failures=806
internal_compile_panics=0
loops_aborted=0
loops_compiled=2
9 changes: 7 additions & 2 deletions pyre/bench/synth/wasm_ca_trampoline_decline.wasm.jitstats
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Original file line number Diff line number Diff line change
@@ -1,9 +1,14 @@
bridges_compiled=1
bridges_compiled=3
descr_set_absent=0
descr_set_ambiguous=0
descr_set_stale_absent=0
fbw_blackhole_adopted_multi_frame=0
fbw_blackhole_adopted_single_frame=0
fbw_rolled_back_with_effects=0
guard_failures=404
fbw_store_journal_rollback_failed=0
field_pos_attached_misplaced=0
field_pos_spec_misplaced=0
guard_failures=601
internal_compile_panics=0
loops_aborted=1
loops_compiled=2
9 changes: 4 additions & 5 deletions pyre/pyre-jit-trace/src/jitcode_dispatch/fbw_state.rs
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Expand Up @@ -1357,10 +1357,9 @@ fn fbw_deny_hazardous_inline(callee_code_key: usize) {
/// the iterator (the two `foriter_exempt_*` witnesses).
/// * **Self-recursive** — the callee calls itself. A hot self-recursion
/// forms a `CALL_ASSEMBLER` bridge whose moving-nursery callee frame cannot
/// survive the residual trampoline retaining a pre-call frame pointer; on
/// the wasm always-portal path the inlined body also type-confuses the
/// optimizer (`setintbound: got Ref`, the `wasm_ca_trampoline_decline`
/// witness). Detected both dynamically (the same `w_code` already nested in
/// survive the residual trampoline retaining a pre-call frame pointer (the
/// `wasm_ca_trampoline_decline` witness). Detected both dynamically (the
/// same `w_code` already nested in
/// the framestack — mutual/deep recursion) and statically
/// (`code_is_self_recursive`), since the recursive call residualizes to a
/// `CALL_ASSEMBLER` rather than nesting the framestack, so it is already a
Expand Down Expand Up @@ -1426,7 +1425,7 @@ pub(crate) fn fbw_abort_nested_unjournaled_residual<Sym: WalkSym>(
// [`fbw_inline_callee_hazardous`]: a LOOP-BEARING callee (the FOR_ITER
// Option-C refused-delivery double-advance, the `foriter_exempt_*`
// witnesses) and a SELF-RECURSIVE callee (the hot `CALL_ASSEMBLER`
// recursion-bridge / wasm always-portal `setintbound` type-confusion, the
// recursion-bridge frame the residual trampoline cannot retain, the
// `wasm_ca_trampoline_decline` witness). Both are properties of the
// framestack knowable at the residual decline point, so the whole trace
// aborts before the hazardous body is committed. Every other nested
Expand Down
22 changes: 9 additions & 13 deletions pyre/pyre-jit-trace/src/jitcode_dispatch/inline_call.rs
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Expand Up @@ -2865,13 +2865,10 @@ pub(crate) fn try_walker_inline_resolved_user_call<Sym: WalkSym>(
// body sub-walk reaches its own recursive CALL as a nested residual, which
// `fbw_abort_nested_unjournaled_residual` declines on the self-recursive
// hazard arm — an abort storm that folds the whole guard bridge back to
// residual. The native `CALL_ASSEMBLER` self-recursion fold already exempts
// that decline via `SELFREC_CA_FOLD_ACTIVE`; the same exemption applies to
// this admitted inline, whose recursive residual runs concretely at the
// pre-execute site (executed, so no replay double-apply). Native only: the
// wasm always-portal path type-confuses the self-recursive inline
// (`setintbound: got Ref`), so it keeps the correct residual-fallback
// decline.
// residual. The `CALL_ASSEMBLER` self-recursion fold already exempts that
// decline via `SELFREC_CA_FOLD_ACTIVE`; the same exemption applies to this
// admitted inline, whose recursive residual runs concretely at the
// pre-execute site (executed, so no replay double-apply).
let mut bridge_rec_root_selfrec = false;
if ctx.trace_ctx.is_bridge_trace
&& args_all_builtin_integer
Expand Down Expand Up @@ -2911,12 +2908,11 @@ pub(crate) fn try_walker_inline_resolved_user_call<Sym: WalkSym>(
if !safe_root_bridge {
return Ok(None);
}
bridge_rec_root_selfrec = cfg!(not(target_arch = "wasm32"))
&& unsafe {
let raw = pyre_interpreter::w_code_get_ptr(w_code as pyre_object::PyObjectRef)
as *const pyre_interpreter::CodeObject;
!raw.is_null() && pyre_interpreter::code_is_self_recursive(&*raw)
};
bridge_rec_root_selfrec = unsafe {
let raw = pyre_interpreter::w_code_get_ptr(w_code as pyre_object::PyObjectRef)
as *const pyre_interpreter::CodeObject;
!raw.is_null() && pyre_interpreter::code_is_self_recursive(&*raw)
};
Comment on lines +2918 to +2922

@chatgpt-codex-connector chatgpt-codex-connector Bot Aug 7, 2026

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P2 Badge Scope the exemption to a proven recursive call

This removal newly enables the exemption on wasm whenever code_is_self_recursive returns true, but that predicate only looks for any LOAD_GLOBAL of the code object's own name; a non-recursive function that merely reads its own global name is therefore sufficient. If such a function reaches this root-bridge path and inlines a loop-bearing helper, bridge_rec_root_selfrec installs SELFREC_CA_FOLD_ACTIVE around the entire body walk, causing fbw_abort_nested_unjournaled_residual to skip the helper's loop-bearing hazard as well and allowing the documented iterator double-advance on replay. Restrict the exemption to the actual recursive CALL_ASSEMBLER site rather than trusting this coarse code-level predicate.

AGENTS.md reference: AGENTS.md:L14-L19

Useful? React with 👍 / 👎.

}
// A callee `fbw_abort_nested_unjournaled_residual` already named on its
// hazard arm residualizes from here on. The hazard is a static property of
Expand Down
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