runtime: preserve recover error values by cpunion · Pull Request #1882 · xgo-dev/llgo

cpunion · 2026-05-22T02:48:30Z

Summary

Panic with runtime error values instead of plain strings so recover() values assert to error and runtime.Error.
Build TypeAssertionError values for compiler-generated failed type assertions, and fix slice-to-array conversion panic bounds order.
Preserve direct recover semantics through compiler-generated method wrappers when the wrapper is itself the deferred call, while keeping nested wrapper calls non-recovering.
Preserve Go 1.26 embedded method-wrapper function pointer semantics for fixedbugs/issue73917.go and fixedbugs/issue73920.go: a recover in a real helper call reached through deferred promoted wrappers remains indirect, and the outer deferred recover still sees the panic.
Preserve local values across fault-triggered longjmp recovery by emitting volatile loads/stores for local SSA allocs in functions with recover blocks.
Add focused test/go coverage for recovered runtime errors, type assertion panic values, method-wrapper recover semantics, embedded wrapper function-pointer recover semantics, and fault recovery preserving named results; remove the now-passing recover2.go, zerodivide.go, recover4.go, fixedbugs/issue73917.go, and fixedbugs/issue73920.go GOROOT xfails.

Still XFail / Out of Scope

recover.go remains xfail in this PR. On this branch it still fails before the recover-10 path with the ssa: panic with runtime type assertion errors #1892 interface type identity issue: interface conversion: interface {} is func(*main.T1), not func(*main.T1) (types from different scopes).
This PR does not cherry-pick ssa: panic with runtime type assertion errors #1892. The recover-wrapper behavior exposed by missing recover 10 is covered independently by test/go.
The new embedded-wrapper test/go cases are Go 1.26+ semantic coverage. Go 1.24 has pre-Go 1.26 behavior for the upstream issue73917.go/issue73920.go programs, so those local tests skip under Go <1.26.
A full Go 1.26 standard-library run of test/go currently hits unrelated nil/range behavior in TestRangeOverNilArrayPointerCallIsEvaluated; this PR intentionally does not cover nil/range, chan, print, interface, reflect, GC, liveness, finalizer, or goroutine domains.

Testing

go test ./test/go -run 'TestRecoverThrough|TestRecoverAfterFault' -count=1
go run ./cmd/llgo test -run 'TestRecoverThrough|TestRecoverAfterFault' -count=1 ./test/go
go test ./test/goroot -run TestGoRootRunCases/recover4.go -count=1 -args -goroot "$(go env GOROOT)" -dirs . -case '^recover4\.go$' -xfail /tmp/llgo-empty-xfail.yaml
go test ./test/goroot -run TestGoRootRunCases/recover4.go -count=1 -args -goroot "$(go env GOROOT)" -dirs . -case '^recover4\.go$'
go test ./test/goroot -run TestGoRootRunCases/recover.go -count=1 -args -goroot "$(go env GOROOT)" -dirs . -case '^recover\.go$' (passes via retained xfail)
go test ./test/goroot -run TestGoRootRunCases/recover.go -count=1 -args -goroot "$(go env GOROOT)" -dirs . -case '^recover\.go$' -xfail /tmp/llgo-empty-xfail.yaml (expected failure: ssa: panic with runtime type assertion errors #1892 interface type identity blocker)
go test ./test/go -run 'TestDeferredEmbedded.*MethodWrapperKeepsIndirectRecoverNil|TestRecoverThrough' -count=1
/Users/lijie/sdk/go1.26.0/bin/go test ./test/go -run 'TestDeferredEmbedded.*MethodWrapperKeepsIndirectRecoverNil' -count=1 -v
/Users/lijie/sdk/go1.26.0/bin/go run ./cmd/llgo test -run 'TestDeferredEmbedded.*MethodWrapperKeepsIndirectRecoverNil|TestRecoverThrough' -count=1 ./test/go
go test ./test/goroot -run TestGoRootRunCases -count=1 -args -goroot /Users/lijie/sdk/go1.26.0 -dirs fixedbugs -case '^fixedbugs/issue739(17|20)\.go$'
go test ./test/go -count=1
(cd runtime && go test ./internal/runtime -count=1)
go test ./ssa -count=1
go test ./cl -count=1
/Users/lijie/sdk/go1.26.0/bin/go test ./test/go -count=1 (known unrelated failure: TestRangeOverNilArrayPointerCallIsEvaluated nil array pointer range SIGSEGV)

GOROOT CI

Full GOROOT CI is disabled/too slow for regular PR validation in this repo and the GOROOT workflow is manual-only. This PR keeps stable coverage in test/go and lists the exact targeted GOROOT commands above. I will monitor the available PR checks after pushing the fork head branch; I will not push branches to xgo-dev/llgo.

cpunion · 2026-05-22T02:49:46Z

CI note: normal PR CI is running from the fork branch cpunion:codex/goroot-panic-coverage.

I attempted to dispatch the manual-only GOROOT workflow for the PR head branch, but GitHub rejected the upstream dispatch because the ref only exists on the fork:

HTTP 422: No ref found for: codex/goroot-panic-coverage

I also attempted to dispatch .github/workflows/goroot.yml on cpunion/llgo at the fork branch, but GitHub returned:

HTTP 404: workflow .github/workflows/goroot.yml not found on the default branch

Per branch policy, I did not push an upstream xgo-dev/llgo ref. Local targeted GOROOT commands are listed in the PR body.

cpunion · 2026-05-22T08:59:52Z

Updated PR after rebasing onto current xgo-dev/main and adjusted the new genericembediface FileCheck expectation for the runtime.TypeAssertError path introduced by this branch.

Additional tests run locally:

go test ./cl ./ssa -run 'TestRunAndTestFromTestgo/genericembediface|TestFromTestgo/genericembediface' -count=1
go test ./test/go -run 'TestRecoveredRuntimePanicsAreErrors|TestRecoveredTypeAssertionPanicsAreRuntimeErrors' -count=1
go test ./test/goroot -run TestGoRootRunCases -count=1 -timeout=10m -args -goroot "$(go env GOROOT)" -dirs . -case '^(recover2|zerodivide)\.go$' -run-timeout=60s -build-timeout=3m
git diff --check

The earlier Ubuntu gpg: no valid OpenPGP data found failure occurred during dependency setup before repository tests ran, so the new push should trigger regular PR CI again from the fork branch.

codecov-commenter · 2026-05-22T20:28:51Z

Codecov Report

❌ Patch coverage is 41.32678% with 1194 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
benchmark/runtime_funcinfo/main.go	0.00%	672 Missing ⚠️
internal/pclnpost/binary.go	12.91%	181 Missing and 1 partial ⚠️
internal/pclnpost/write.go	0.00%	150 Missing ⚠️
internal/pclnpost/fixups.go	0.00%	125 Missing ⚠️
internal/pclnpost/pclnpost.go	0.00%	22 Missing ⚠️
internal/pclntab/pclntab.go	61.40%	11 Missing and 11 partials ⚠️
cl/instr.go	97.09%	10 Missing and 5 partials ⚠️
ssa/eh.go	92.45%	2 Missing and 2 partials ⚠️
cl/compile.go	98.88%	1 Missing and 1 partial ⚠️

📢 Thoughts on this report? Let us know!

cpunion · 2026-05-24T03:46:15Z

Update from commit 6b65c2c:\n\n- Fixed direct vs indirect recover scoping and nested panic stack handling; removed the recover1.go xfail entries covered by this PR.\n- Kept recover.go xfails: the remaining failure is reflect/interface type identity in test9reflect2, not the recover/defer panic root.\n- Kept recover4.go xfails: SIGBUS is now routed to the panic path, but the remaining mismatch is stale local/named-result state after fault recovery (memcopy returned 0 vs 131067), which I am not mixing into this recover/defer PR.\n- Kept deferprint.go and fixedbugs/bug409.go xfails: remaining mismatches are float print exponent formatting (+e+00 vs +e+000).\n\nLocal validation:\n- go test ./test/go -count=1\n- go test ./test/goroot -count=1 -run TestGoRootRunCases -args -goroot $(go env GOROOT) -dirs .,fixedbugs -case '^(recover.go|recover1.go|recover4.go|deferprint.go|fixedbugs/bug409.go)$' -run-timeout=30s\n- go test ./ssa ./cl -count=1\n- cd runtime && go test ./internal/runtime -count=1

cpunion · 2026-05-24T04:48:14Z

Update after 77ceb09:

Added focused recover/defer coverage in test/go for deferred method wrappers and direct-defer recover semantics.
Added fault recover coverage for preserving a named result after a protected-memory fault path.
Fixed recover-frame forwarding through recover-transparent wrappers and made recover-function local alloc loads/stores volatile so fault longjmp keeps observable locals.
Removed the recover4.go goroot xfails now that it passes independently on this branch.
Kept recover.go xfail: without ssa: panic with runtime type assertion errors #1892 it still stops first on the interface type-identity panic, so this PR does not cherry-pick the interface fix. The recover-wrapper behavior is covered independently in test/go.

Focused tests passed locally: test/go recover cases via Go and llgo, recover4.go goroot with and without xfail, recover.go goroot with retained xfail, go test ./test/go, go test ./ssa, go test ./cl, and runtime/internal/runtime inside the runtime module.

cpunion · 2026-05-24T06:03:45Z

Update for commit 66a820936f3baab3164393d63f95d944fd9566fb:

Classified fixedbugs/issue73917.go and fixedbugs/issue73920.go as Go 1.26 embedded method-wrapper function-pointer defer/recover semantics. Both are in the same recover/defer wrapper scope as this PR.
Added test/go coverage for value and pointer promoted method wrappers reached through function pointers, keeping the helper recover indirect so the outer deferred recover still receives the panic.
Removed the now-passing Go 1.26 xfails for both cases on darwin/arm64 and linux/amd64.
Left nil/range, interface ssa: panic with runtime type assertion errors #1892, GC/liveness/finalizer/goroutine, chan, print, reflect, and related non-wrapper domains untouched.

Focused checks passed:

go test ./test/goroot -run TestGoRootRunCases -count=1 -args -goroot /Users/lijie/sdk/go1.26.0 -dirs fixedbugs -case '^fixedbugs/issue739(17|20)\.go$'
/Users/lijie/sdk/go1.26.0/bin/go test ./test/go -run 'TestDeferredEmbedded.*MethodWrapperKeepsIndirectRecoverNil' -count=1 -v
/Users/lijie/sdk/go1.26.0/bin/go run ./cmd/llgo test -run 'TestDeferredEmbedded.*MethodWrapperKeepsIndirectRecoverNil|TestRecoverThrough' -count=1 ./test/go
go test ./test/go -count=1
(cd runtime && go test ./internal/runtime -count=1)
go test ./ssa -count=1
go test ./cl -count=1

Known unrelated non-covered check: /Users/lijie/sdk/go1.26.0/bin/go test ./test/go -count=1 fails in TestRangeOverNilArrayPointerCallIsEvaluated with a nil array pointer range SIGSEGV, which is outside this recover/defer wrapper PR.

cpunion · 2026-05-24T07:35:14Z

Update for fixedbugs/issue43835.go at 5fc53956f98a7718eab8399fd905756b7f058ece:

Classified as the same recover/defer/named-result-after-panic family: the nil deref is only the panic trigger; after deferred recover, partial true writes from an unfinished assignment/return must not be observed.
Implemented a compiler-side ordering fix for recover-capable functions: explicit nil-deref assertion before deref loads that could otherwise be eliminated/moved past result writes; existing volatile result-slot handling remains scoped to recover blocks.
Added stable test/go coverage for assignment, unnamed return, and named return expression forms.
Removed only the now-covered fixedbugs/issue43835.go xfails for darwin/arm64 and linux/amd64. No GC/liveness/finalizer/goroutine, chan, print, interface, or broader nil-domain changes are included.

Local validation:

go test ./test/goroot -run TestGoRootRunCases -count=1 -timeout 30m -args -goroot /Users/lijie/sdk/go1.26.0 -dirs fixedbugs -case '^fixedbugs/issue43835\\.go$' -directive-mode runlike -run-timeout 2m\n- go test ./test/go -count=1\n- go test ./ssa -count=1\n- go test ./cl -count=1\n\nRuntime package tests were not rerun for this increment because no runtime code changed.

cpunion · 2026-06-06T03:41:45Z

Resolved the latest merge conflict with xgo-dev/main (51d665e). Kept recover1.go/recover4.go out of xfail for this PR's recovered panic value fix, while preserving unrelated main xfails such as issue73917/issue73920.\n\nLocal verification:\n- go test -timeout 20m ./test/go -run 'Test(Recover|RuntimeError|Panic|GenericUnsafeSizeofArithmetic)' -count=1\n- go test -timeout 20m ./test/goroot -run TestGoRootRunCases -count=1 -args -goroot /Users/lijie/sdk/go1.26.0 -case '^(recover1|recover4).go$' -run-timeout 60s\n- git diff --check

cpunion · 2026-06-06T04:55:45Z

Update for 259389962:

Added package-level coverage for the recover-frame helper paths that Codecov previously reported as uncovered: direct deferred recover, MaskRecoverCall, ForwardRecoverFrameCall, emitDoEx mask/forward modes, and transparent wrapper detection.
Kept the change scoped to panic/recover error-value preservation; no GC/liveness/finalizer/goroutine changes.

Local validation:

go test ./ssa -run 'Test(PlainDeferWithoutSavedArgsIR|DeferredRecoverBuiltinDoesNotStartNestedFrameIR|RecoverFrameCallHelpersIR)' -coverprofile=/tmp/llgo-ssa-recover.out -covermode=count -count=1
- covered callRecoverScopedDefer, MaskRecoverCall, and ForwardRecoverFrameCall at 100% in the focused profile.
go test ./cl -run 'Test(EmitDoWithExplicitDeferStack|EmitDoWithoutExplicitDeferStack|EmitDoRecoverFrameModes|RecoverTransparentWrapperCall)' -coverprofile=/tmp/llgo-cl-recover.out -covermode=count -count=1
- covered emitDoEx and recoverTransparentWrapperCall at 100% in the focused profile.
go test -timeout 20m ./test/go -run 'Test(Recover|RuntimeError|Panic|GenericUnsafeSizeofArithmetic)' -count=1
go test -timeout 20m ./test/goroot -run TestGoRootRunCases -count=1 -args -goroot /Users/lijie/sdk/go1.26.0 -case '^(recover1|recover4)\\.go$' -run-timeout 60s
git diff --check

Also checked broader local package runs. They still hit pre-existing, unrelated failures that I did not change in this recover/panic PR: go test ./ssa -count=1 and go test ./cl -count=1 fail on cl/_testdata/vargs expecting AssertIndexRange while the current IR emits CheckIndexRange; go test ./test/go -count=1 fails on legacy print exponent width (+e+000 vs +e+00).

CI and Codecov are expected to rerun from the fork branch after this push.

cpunion · 2026-06-06T06:08:39Z

Updated the stale FileCheck expectation in cl/_testdata/vargs/in.go from AssertIndexRange(i1) to the current CheckIndexRange(i1, i64, i1, i64) IR emitted by litgen.

Local verification passed:

go test ./cl -run TestRunAndTestFromTestdata
go test ./cl ./ssa

The remaining public test/go print failure is still tracked separately in #1945 and was not changed here.

zhouguangyuan0718 · 2026-06-29T16:22:47Z


+// declare ptr @llvm.frameaddress.p0(i32 immarg)
+func (b Builder) FrameAddress(level uint64) Expr {
+	fn := b.Pkg.cFunc("llvm.frameaddress.p0", b.Prog.tyFrameaddress())


这个可以改成用新封装的CreateIntrinsic来调用，可以参考

llgo/ssa/eh.go

Line 83 in 377e737

b.impl.CreateIntrinsic(b.Prog.VoidPtr().ll, llvm.LookupIntrinsicID("llvm.stacksave"), nil, ""),

frameFuncForPC could cache a Func built from a pcline frame whose entry resolution failed (entry == 0); a later FuncForPC on the same PC would then observe Entry() == 0 where its own constructor falls back to pc. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

LLGO_FUNCINFO_SITES=0 keeps the funcinfo metadata tables but drops the body-embedded entry/stub/pc-line inline-asm sites. This is the narrow A/B needed to isolate codegen perturbation caused by the in-body asm anchors: with sites off, plain-code benchmarks match the no-funcinfo baseline within noise, while sites on shifts hot runtime-internal loops by -30%..+6% through inline/layout decisions. Semantics with sites off: FuncForPC(entry) and Func.FileLine(entry) keep working through the dlsym fallback path; statement/call-site granularity PC line lookup is disabled, and first-use table construction loses the section fast path. Tests assert the split: tables still materialize while entry/stub section asm, boundary symbols, and pc-line site labels are all absent. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

First stage of doc/design/pclntab-linkphase.md: parse a linked binary's funcinfo entry/stub sections (Mach-O and ELF), deduplicate LTO inline copies against the symbol table's text ranges, sort with a Go-style sentinel, and build findfunctab through internal/pclntab — the faithful port that has been waiting for exactly this caller. Read-only: prints what the P2 build integration would write back. Measured on the 576-target multipkg binaries: - non-LTO: 9319 records -> ftab 3161 + 207 buckets; lookup self-check 3160/3160; site sections 149KB -> 29KB (5.1x) - LTO: 15371 entry records -> 13857 inline copies dropped, 4144 kept; self-check 3045/3045; 299KB -> 28.5KB (10.5x) Findings for P2: on-disk Mach-O pointer slots hold dyld chained-fixup encodings (low 36 bits are the target; decoded here; the write-back design stores anchor-relative offsets and avoids pointers entirely), and some non-LTO stub symbols are absent from the symbol table (records conservatively dropped; needs tightening). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

…adoption pclnpost -write rewrites the entry-site section in place with the prebuilt table (header + ftab {entryOff,funcIndex} + runtime-layout findfunctab buckets), resolving funcinfo indexes through the binary's symbol-index section, and voids the stub section (its records are merged into the table). ASLR is handled by anchoring on the section's own link-time address; entries are normalized to true symbol starts, which retires the entry-PC slack on this path. macOS re-signs with an ad-hoc codesign after rewriting. The runtime adopts the table zero-copy when the magic header validates: lookups binary-search the on-disk ftab directly through the shared bucket index, nothing is materialized on first use (the funcIndex -> entry map is built lazily and only for the pcline initializer), and the cold scan/dladdr path is skipped since adoption is cheap. First-use construction remains the fallback whenever the header is absent. Linux end-to-end: entries=prebuilt, FuncForPC/FileLine correct, first-FuncForPC 110µs (materializing) -> 6-8µs (zero-copy); 13ms on the original macOS baseline. Known gap: on macOS the on-disk rewrite is corrupted at load time because dyld still walks the stale chained-fixup chain over the section; fix (unlinking the section's nodes from the page chains in LC_DYLD_CHAINED_FIXUPS) is identified and next. Non-prebuilt paths verified regression-free: cl + test/go suites pass, smoke behavior unchanged. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Every llgo-linked executable (linux/darwin, sites enabled) now gets the prebuilt ftab/findfunctab automatically: internal/build runs internal/pclnpost.Rewrite after linkMainPkg, and any failure degrades silently to the first-use construction fallback. Moves the tool core into internal/pclnpost and hardens it: - Canonical-record detection by FNV: a record survives when its anchor's owning symbol hashes to the record's symbolID (or is the __llgo_stub. wrapper of it). The previous one-per-symbolID rule wrongly collapsed a function with its stub — they share the target's symbolID by design — which broke exact-entry lookups (caught by TestRuntimeLineInfoAndStack on Linux). LTO inline copies are now identified exactly: 8.4k/9.5k copies removed in the LTO probes. - Mach-O chained-fixups surgery: unlink the rewritten sections' pointer slots from the dyld page chains (repointing predecessors' next links and page_start entries) so dyld neither rebases slots inside the new table nor skips unrelated fixups after the zeroed stub section, then re-sign ad hoc. Without this the table was corrupted at load. - LTO-safe metadata location: the entry section carries a meta record whose relocations hold the addresses of the symbol-index pointer and count globals; LTO internalization strips those names from the symbol table but relocations always resolve. Runtime skips the meta rows (pc==0 / symbolID==0). - Idempotence guard (already-rewritten binaries are left alone). Runtime fixes that surfaced during validation: - materializePrebuiltEntries is now two-phase so concurrent losers wait for the winner's store instead of reading a nil entries slice. - pcLineFrameForPC rejects nearest-below sites whose entry is unresolved when the caller knows the function entry, instead of leaking a neighboring function's file/line. Validation: macOS cl (full) + test/go + LLDB 194/194; Linux test/go TestRuntime suite; probes on both platforms report entries=prebuilt with first-FuncForPC at 7-21µs (Linux) from 13ms on the original baseline, and LTO builds drop 8-9.5k inline copies. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

…table On Mach-O, pointer slots that name exported functions — every __llgo_stub.* wrapper and any exported Go function — are emitted as chained-fixup BIND nodes, not rebases. The rewriter only decoded rebase nodes, so all stub records (and some entry records) were dropped as unowned and never reached the prebuilt ftab; FuncForPC on function values silently fell back to dladdr (~6µs per fresh pc on darwin). - Parse the LC_DYLD_CHAINED_FIXUPS imports table and resolve bind ordinals to their in-image definitions. - Match canonical owners against the record symbolID with underscore normalization (debug/macho's suffix-shared string table can surface one mangling underscore more or less than the source-level name). - Splice the prebuilt header's base slot back into the fixup chain as a live rebase node: dyld writes the slid text base at load, so the runtime reads a ready runtime PC with no slide arithmetic (non-PIE ELF link-time values already equal runtime addresses). - LLGO_PCLNPOST=0 escape hatch keeps first-use construction. Fresh-pc FuncForPC slow path: darwin 6-8µs -> 1.2-1.7µs, linux 6.8µs -> 0.5µs; first-in-process lookup: darwin ~32µs -> ~14µs, linux ~6.8µs -> ~4µs. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Pure-compute probes (recursive fib, JSON round-trip, sort.Ints, map churn) with no runtime introspection, so one harness run covers both the introspection extremes and what the funcinfo machinery costs code that never asks for it. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Go's pclntab pages are touched by its own runtime (traceback, GC) long before user code queries it, so its first FuncForPC never pays page-in. Mirror that: when the prebuilt table is present, init adopts it (zero-copy, sub-µs), touches the pages the lookup path reads (blob, funcinfo records, string offsets, strings), runs one synthetic lookup to warm the code paths, and write-warms the FuncForPC cache pages. First-in-process FuncForPC: darwin ~17µs -> ~2.8µs, linux ~6.6µs -> ~1.0µs. Startup cost is page-count-bound (tens of µs on stdlib-sized tables, invisible next to ~3ms process startup; hello-world medians unchanged). Non-prebuilt binaries stay fully lazy: first-use construction allocates, which has no place in init, and programs that never introspect pay nothing. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

-depths generates deep_<N> scenarios at configurable call depths; -bigsizes generates bigfunc scenarios (funcs x statements) whose large bodies stress statement-level pcline density, mid-function pc symbolization, and ordinary performance of big method bodies. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

cpunion · 2026-07-02T15:03:41Z

Rebased onto #2016 (codex/pclntab-linkphase-p1, which includes #2012) per the review-order plan: #2012 → #2016 → this line of semantics fixes. Conflicts resolved were additive (context fields, the noinline condition set, and runtime.Panic now calls SavePanicCallerFrames() before the panic-node bookkeeping). Note the PR base is still main, so the diff shows #2012/#2016 commits until those merge.

cpunion · 2026-07-06T07:57:05Z

Superseded by #2034, which re-expresses the recover-error-value semantics (real runtime.TypeAssertionError values, SIGBUS fault path, recover2/4 + zerodivide + issue73917/73920 conformance) on top of #2033's Defer-node model; the funcinfo draft carried here was superseded by #2012/#2016/#2019. The recursive-panic sub-call masking piece (recover1.go) is tracked as a #2033-model follow-up.

…s; recover conformance Re-expresses the surviving value of xgo-dev#1882 on top of xgo-dev#2033 (its remaining ~11k diff lines were the pre-xgo-dev#2012 funcinfo draft, superseded): - Failed (non-comma-ok) type assertions panic with a real *runtime.TypeAssertionError built at runtime (TypeAssertError + missing-method lookup from abi tables) instead of a plain errorString; the recovered value implements runtime.Error, matching gc. The source-interface abi type is deliberately not materialized at the assert site: doing so can reference another package's private local-generic symbols (undefined at link); the message's interface name is the documented mdempsky/16 residual. - SIGBUS joins SIGSEGV in the fault-to-panic signal path (per-OS signal constants; darwin/linux). - goroot xfails retired, validated darwin go1.26 + go1.24: recover2.go, recover4.go, zerodivide.go, fixedbugs/issue73917.go, issue73920.go. - recover1.go stays xfailed with an updated reason (recursive-panic sub-call recover masking - Defer-node model follow-up); three ported tests covering the same class are t.Skip'ed with that pointer. - Golden CHECK updates: assert-failure sites now emit TypeAssertError+Panic; constants renumbered from actual IR. Supersedes xgo-dev#1882.

cpunion force-pushed the codex/goroot-panic-coverage branch from 699e9cf to 82b8a1a Compare May 22, 2026 08:59

cpunion mentioned this pull request May 24, 2026

ssa: panic with runtime type assertion errors #1892

Closed

cpunion marked this pull request as ready for review June 1, 2026 04:27

cpunion force-pushed the codex/goroot-panic-coverage branch 3 times, most recently from 5a10a71 to f7ea6d7 Compare June 10, 2026 11:31

cpunion force-pushed the codex/goroot-panic-coverage branch from 5c0bf1f to f29c5d6 Compare June 20, 2026 03:12

cpunion force-pushed the codex/goroot-panic-coverage branch 3 times, most recently from 17cfabb to 5bb0176 Compare June 29, 2026 02:26

zhouguangyuan0718 reviewed Jun 29, 2026

View reviewed changes

cpunion added 9 commits July 2, 2026 03:27

build: add Go-style pclntab findfunc index

2870ba8

ssa: emit DCE-safe function metadata

f365b73

runtime: add line info for stack frames

e81a007

runtime: add statement line caller frames

1e15db2

runtime: compress funcinfo table

407e0dd

test: cover indirect runtime caller paths

a3115cd

cl: narrow runtime caller tracking

c6c128a

runtime: add compact pc-line funcinfo table

4692e15

runtime: optimize FuncForPC metadata lookup

b29906c

cpunion and others added 22 commits July 2, 2026 19:13

doc: record P3 findings in pclntab-linkphase design

cd8506d

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

benchmark: keep full LTO from constant-folding the plain fib probe

a3e679c

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

runtime: preserve recover error values

a17d41a

runtime: scope recover to deferred caller frame

61ad841

runtime: preserve recover state across wrappers and faults

2d2f551

test: cover Go 1.26 embedded wrapper recover

a096cec

cl: preserve recover results after nil deref

107ce54

test: cover recover frame helpers

649475f

test: update invoke type assertion checks

25ed50c

ssa: avoid recover frame cleanup after unreachable

c125ac1

test: keep cSqrt linkname adjacent

e8fc053

test: refresh panic defer fixtures

08e6d5f

cl: preserve interface compare nil guard

bd1d08c

cpunion force-pushed the codex/goroot-panic-coverage branch from 5bb0176 to bd1d08c Compare July 2, 2026 15:03

This was referenced Jul 2, 2026

Proposal: runtime funcinfo metadata and fast FuncForPC lookup #2004

Open

runtime: tighten recover to direct deferred calls #1918

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ssa,runtime: real runtime.Error values for type asserts and fault signals #2034

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cpunion closed this Jul 6, 2026

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cpunion commented May 22, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Summary

Still XFail / Out of Scope

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cpunion commented May 22, 2026

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cpunion commented May 24, 2026

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cpunion commented May 24, 2026

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cpunion commented May 24, 2026

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cpunion commented May 24, 2026

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cpunion commented Jun 6, 2026

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cpunion commented Jun 6, 2026

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cpunion commented Jun 6, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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zhouguangyuan0718 Jun 29, 2026

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cpunion commented Jul 2, 2026

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cpunion commented Jul 6, 2026

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cpunion commented May 22, 2026 •

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cpunion commented Jun 6, 2026 •

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