bugc: emit tailcall transform context on TCO back-edge#217
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The TCO back-edge JUMP already carries a flat context with both invoke (the new iteration's call) and return (the previous iteration's return). Add a third sibling key, transform: ["tailcall"], marking the instruction as a tail-call-optimized back-edge. This is an additive annotation: it does not replace the invoke/return pair (which state the source-level facts) but tells debuggers the pair was realized as a TCO back-edge rather than a real frame push/pop, so they can avoid inventing a spurious frame. Consumers that ignore transform contexts still get a sound source-level view from invoke/return alone. Widens the emitted context type to Return & Invoke & Transform and extends the optimizer-contexts test to assert the back-edge JUMP carries transform containing "tailcall".
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This was referenced Jul 2, 2026
gnidan
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bugc #217 emits the TCO back-edge as a single flat context object (return + invoke + transform keys together), but the existing tests only exercised the gather shape. Add flat-shape variants for transform extraction, the isTailCall flag, and frame replacement, plus a guard that stripping the marker (the #10 failure mode) drops tail-call handling.
gnidan
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…n panels (#222) * web: fix tracer-drawer opcodes/state panels not filling height The trace panels live in a flex:1 grid whose implicit row was auto- sized to content, so dragging the drawer taller left dead space below the panels instead of growing them. Give the grid an explicit 1fr row and min-height:0 (on the grid and its items) so both panels absorb the added vertical space and scroll internally. * web: add optimizer-level selector (O0/O2) to tracer drawer The drawer hardcoded optimizer level 0. Add an O0/O2 toggle in the drawer header that recompiles + retraces at the chosen level, so readers can flip to level 2 and watch optimizer transforms (e.g. the tailcall annotation on TCO back-edges) appear. compileAndTrace now takes the level explicitly; a ref mirrors the state so the example- load effect reads the current level without re-running on toggle. * programs-react: cover the flat (production) TCO back-edge shape bugc #217 emits the TCO back-edge as a single flat context object (return + invoke + transform keys together), but the existing tests only exercised the gather shape. Add flat-shape variants for transform extraction, the isTailCall flag, and frame replacement, plus a guard that stripping the marker (the #10 failure mode) drops tail-call handling. * web: dedupe call stack + tailcall render + right-column panels - Reuse the shared, tailcall-aware buildCallStack / extractCallInfo / extractTransform from @ethdebug/programs-react via a thin adapter (bugc .debug.context -> ethdebug format shape); drop the drawer's inline call-stack builder and local extractCallInfo. - Render the tail-call chip on the reused call-stack frame and a tail-call variant on the call-info banner. - Right column (gnidan's picks 1/2/4): resolved variable values (name: value via pointer resolution), gas remaining + per-step delta, and a transform annotations panel with per-tag glosses. Sections are now collapsible. * web: widen optimizer selector to O0/O1/O2/O3 gnidan's call: expose all four bugc optimizer levels (each distinct — L1 fold/prop/DCE, L2 +CSE/TCO/jump-opt, L3 +merging) rather than a two-state O0/O2 toggle, future-proofing for other transforms. The recompile+retrace already took the level; just widen the control from two buttons to four (mapped over OPT_LEVELS, per-level tooltips). The tailcall demo still lands on O2.
gnidan
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Refactor buildTailCallJumpOptions to emit its transform:["tailcall"] marker via Ir.Utils.addTransform instead of a hand-written key, so all transform emission (fold/tailcall/coalesce/...) routes through the one helper. Behavior is identical — the back-edge JUMP still carries return + invoke + transform:["tailcall"] — but composition stays consistent (e.g. a folded-then-tailcall instruction would accumulate the multiset) and there's no divergent hand-rolled site. Existing #217 tailcall tests pass unchanged.
gnidan
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* bugc: emit fold transform on constant folding Marks constant-folded values with transform:["fold"] so debuggers can show that a value is a compile-time-evaluated constant rather than source the user wrote. Adds Ir.Utils.addTransform(debug, ...ids), which composes transform markers as a flat sibling key on a debug context (per the flat- composition convention) and appends to any existing transform array — so an instruction touched by multiple passes accumulates the multiset (e.g. ["fold","coalesce"]). ConstantFoldingStep applies it to folded binary and hash results. Although a folded const instruction is typically dissolved by constant propagation + DCE, ConstantPropagationStep already carries the folded const's operationDebug into the consuming instruction, so the marker survives to the emitted bytecode's runtimeInstructions (the tracer widget's path) at levels 1-3. Adds an end-to-end test asserting the fold marker reaches the bytecode at levels 1/2/3 and is absent at level 0. * bugc: route tailcall transform through addTransform helper Refactor buildTailCallJumpOptions to emit its transform:["tailcall"] marker via Ir.Utils.addTransform instead of a hand-written key, so all transform emission (fold/tailcall/coalesce/...) routes through the one helper. Behavior is identical — the back-edge JUMP still carries return + invoke + transform:["tailcall"] — but composition stays consistent (e.g. a folded-then-tailcall instruction would accumulate the multiset) and there's no divergent hand-rolled site. Existing #217 tailcall tests pass unchanged.
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Emits a
transform: ["tailcall"]context on the TCO back-edge JUMP, using the transform schema added in #212.The TCO back-edge JUMP already carries a flat context with both
invoke(the new iteration's call) andreturn(the previous iteration's return). This adds a third sibling key,transform: ["tailcall"], marking the instruction as a tail-call-optimized back-edge.Per #212's design, this is an additive annotation — it does not replace the invoke/return pair (which state the source-level facts), but tells debuggers the pair was realized as a TCO back-edge rather than a real frame push/pop, so they can avoid inventing a spurious frame. Consumers that ignore transform contexts still get a sound source-level view from invoke/return alone. Flat sibling-key composition (no
gather) follows the convention #212 established.Changes
evmgen/generation/control-flow/terminator.ts—buildTailCallJumpOptionswidens the emitted context type toReturn & Invoke & Transformand addstransform: ["tailcall"].evmgen/optimizer-contexts.test.ts— asserts the back-edge JUMP carriestransformcontaining"tailcall"at optimizer levels 2 and 3.Verification
yarn build+ full bugc suite green (406 passed, 22 pre-existing skips).countprogram: runtime program emits exactly one back-edge JUMP withtransform: ["tailcall"]+invoke(idcount, code target patched to0x78) +return.