runtime: track caller frames for LLGo metadata

[cpunion]

Summary

• add LLGo-maintained caller frame metadata for runtime.Caller, runtime.Callers, CallersFrames, FuncForPC, and Func.FileLine
• instrument non-runtime Go functions with caller frame push/pop and call-site line updates so metadata survives LLVM inlining
• preserve caller-frame stack marks across recovered panics, set call-site line metadata before evaluating call operands, and normalize LLGo anonymous frame names like $1 to Go-style .func1
• add focused test/go coverage for runtime.Caller, Callers, CallersFrames, FuncForPC, Func.FileLine, line numbers, function names, recovered nil-panic frame metadata, and inline caller/callers metadata
• remove the verified inline_caller.go and inline_callers.go xfails for Go 1.24/1.25/1.26 on linux/amd64 and darwin/arm64, plus Go 1.26 devirtualization_nil_panics.go xfails already covered by this PR

Testing

• go test ./test/go -count=1
• env LLGO_GOROOT_VERBOSE=1 LLGO_GOROOT_HEARTBEAT_SECONDS=60 bash ./dev/test_goroot.sh /Users/lijie/sdk/go1.24.11 /Users/lijie/sdk/go1.25.0 /Users/lijie/sdk/go1.26.0 -- -dirs . -case '^(inline_caller|inline_callers|maymorestack)\\.go$' -directive-mode ci -xfail /tmp/llgo-empty-xfail-missing.yaml -run-timeout 60s (empty xfail reproduction: inline cases pass on darwin/arm64; maymorestack.go still fails with panic: mayMoreStack not called)
• env LLGO_GOROOT_VERBOSE=1 LLGO_GOROOT_HEARTBEAT_SECONDS=60 bash ./dev/test_goroot.sh /Users/lijie/sdk/go1.24.11 /Users/lijie/sdk/go1.25.0 /Users/lijie/sdk/go1.26.0 -- -dirs . -case '^(inline_caller|inline_callers|maymorestack)\\.go$' -directive-mode ci -run-timeout 60s
• (cd runtime && go test ./... -count=1)
• go test ./ssa -count=1
• go test ./runtime/... ./ssa/... ./cl/... -count=1 was attempted from the repo root; ssa/... and cl/... completed successfully, but the command exited 1 because runtime is a separate module and ./runtime/... is not a root-module package pattern
• git diff --check

Scope Notes

• inline_caller.go and inline_callers.go now pass locally on Go 1.24.11, Go 1.25.0, and Go 1.26.0 darwin/arm64 with an empty xfail file; their remaining xfails are removed because they exercise the same runtime caller/debugline metadata path now covered in test/go.
• maymorestack.go remains xfailed for Go 1.24/1.25/1.26 on darwin/arm64 and linux/amd64. Its current local failure is panic: mayMoreStack not called, which is a -d=maymorestack hook/instrumentation issue rather than caller/debugline metadata.
• No nil/chan/print/recover runtime, GC/liveness/finalizer, or goroutine behavior is changed here. I did not push any branch to xgo-dev/llgo.

[cpunion]

Pushed fix 5a8e97f (runtime: limit caller frame instrumentation).\n\nRoot cause from the failed logs: caller-frame instrumentation was enabled for nearly every non-runtime package. That shifted LLVM IR in the FileCheck suites and pulled caller runtime dependencies into embedded/cross-target builds, producing widespread link failures such as stdout/vfprintf/pthread_* undefined symbols.\n\nLocal validation on /Users/lijie/source/goplus/llgo-wt-goroot-debugline:\n- go test ./ssa\n- go test ./test/go -run TestRuntimeCaller\n- go test ./cl (cl package passed; the combined command exited after unrelated runtime/internal direct-package setup failures)\n- go build -o /tmp/llgo-debugline ./cmd/llgo\n- GOWORK=off /tmp/llgo-debugline run . in _demo/go/runtime\n- ../../../dev/llgo.sh build -target ae-rp2040 -o /tmp/llgo-debugline-ae-rp2040-empty.elf ./empty\n- ../../../dev/llgo.sh build -target ae-rp2040 -o /tmp/llgo-debugline-ae-rp2040-defer.elf ./defer\n\nNew CI is queued/running on head 5a8e97f; monitoring now.

[cpunion]

CI follow-up for 5a8e97f:\n\n- Go/test (ubuntu-latest, 19): success\n- Targets/llgo (ubuntu-latest, 19): success\n- LLGo/llgo (ubuntu-latest, 19, Go 1.21.13): success\n- LLGo/llgo (ubuntu-latest, 19, Go 1.24.2): success\n- LLGo/llgo (ubuntu-latest, 19, Go 1.26.0): success\n- LLGo ubuntu test shards and hello jobs observed so far: success\n\nNo failed checks on the new head at this point. Remaining macOS and release-artifact jobs are still queued by GitHub runners.

[codecov-commenter]

⚠️ Please install the to ensure uploads and comments are reliably processed by Codecov.

Codecov Report

❌ Patch coverage is 61.22449% with 57 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
cl/instr.go	57.14%	36 Missing and 6 partials ⚠️
cl/compile.go	72.34%	11 Missing and 2 partials ⚠️
ssa/package.go	0.00%	2 Missing ⚠️

📢 Thoughts on this report? Let us know!

[cpunion]

Updated with fc4eae3. This narrows the new coverage to recovered nil panic -> runtime.CallersFrames metadata: frame stack marks are truncated on return after recover, call-site line metadata is set before callee/receiver evaluation, and LLGo anonymous frame names are normalized to Go-style .funcN. Removed only the Go 1.26 devirtualization_nil_panics.go xfails. I also checked inline_caller.go/inline_callers.go as same caller/debugline domain on Go 1.26 darwin-arm64, but left the remaining inline xfails in place because this commit did not revalidate every listed version/platform for those entries. No xgo-dev branch push.

[cpunion]

Update on bda9687b1734fd8fca652cc4f1ef68f38daca92a:

• Added test/go coverage for inline runtime.Caller, runtime.Callers, runtime.CallersFrames, runtime.FuncForPC, and Func.FileLine metadata.
• Removed inline_caller.go / inline_callers.go xfails for Go 1.24/1.25/1.26 on linux/amd64 and darwin/arm64.
• Kept maymorestack.go xfails. Local empty-xfail reproduction on Go 1.24.11, 1.25.0, and 1.26.0 darwin/arm64 still fails with panic: mayMoreStack not called, which is outside the caller/debugline metadata path.
• Local focused goroot verification with normal xfail now passes for all three local SDKs; maymorestack.go is the expected remaining failure.

CI has been retriggered from the fork head; at the time of this comment the new checks are queued on the PR.