[Based on #114] debug: define the common debugger ABI

[cpunion]

Implements Task 2 of xgo-dev#2164 on top of #114.

Defines a versioned, debugger-independent llgo.debugger schema and a fixed 16-byte ABI record carrying the schema/runtime/LLGo ABI versions, C ABI mode, pointer size, and byte order. Native DWARF builds retain the structured record plus the v1 compatibility marker; embedded and external Wasm artifacts carry the same record in a custom section, including both the deployment module and DWARF sidecar.

The stock-LLDB launcher now installs and consumes the canonical schema, prefers the structured record, preserves marker-v1 fallback, and rejects unknown or target-incompatible records without disabling raw LLDB commands. Shared debugger fixtures cover primitives, aliases and named types, recursive and aggregate values, strings, slices, maps, channels, interfaces, functions, closures, bound methods, and goroutines.

Validation:

• macOS/arm64: affected Go tests and coverage; schema 93.8%, debuginfo 100%, wasmdebug 95.5%, LLDB launcher 87.5%; all new record publication/decoding functions 100% except immutable-schema parse error branches.
• macOS/arm64: 224/224 real LLDB source/value tests; non-LLGo, legacy-unknown, ambiguous, structured-unknown, and target-mismatch fallback checks.
• macOS/arm64 and Linux/amd64 (OrbStack): shared fixture builds and runs with LLGo; Mach-O/ELF records retained.
• macOS/arm64 and Linux/amd64: embedded Wasm, external deployment Wasm, and external DWARF sidecar contain the same validated llgo.debugger record; the deployment module has no embedded DWARF.
• Linux/amd64: affected Go tests and coverage passed. The full process-control LLDB suite remains assigned to native CI because OrbStack LLDB/gdbserver does not preserve the selected frame reliably.

[gemini-code-assist]

Caution

The consumer version of Gemini Code Assist on GitHub has been sunset. All code review activity has officially ceased.

[github-actions]

LLGo baseline benchmarks

d6ab27ae09ae | workflow run | long-term charts

Program measurements

Platform	Workload	File size	vs main	Build	vs main	Run	vs main
Linux	cprintf	18544 B	+0.0%	342.121 ms	-17.0% (better)	1.262 ms	-18.7% (better)
Linux	fmtprintf	2217608 B	+0.2% (worse)	3.450 s	-10.5% (better)	2.448 ms	-25.5% (better)
Linux	println	71504 B	-1.6% (better)	344.147 ms	-14.0% (better)	1.603 ms	-4.2% (better)
macOS	cprintf	84672 B	+0.0%	513.298 ms	+23.9% (worse)	2.902 ms	-19.1% (better)
macOS	fmtprintf	2361520 B	+0.7% (worse)	2.431 s	-38.3% (better)	16.325 ms	-30.2% (better)
macOS	println	125712 B	-1.0% (better)	413.047 ms	-0.4% (better)	5.172 ms	-28.8% (better)

Core language and compiler benchmarks

Platform	Benchmark	ns/op	vs main
Linux	BenchmarkLookupPCRandom	13.280 ns/op	-1.5% (better)
Linux	BenchmarkMergeCompilerFlags	150.600 ns/op	-2.5% (better)
Linux	BenchmarkMergeLinkerFlags	97.520 ns/op	-3.7% (better)
Linux	BenchmarkChannelBuffered	34 ns/op	-2.2% (better)
Linux	BenchmarkChannelHandoff	27759 ns/op	-13.3% (better)
Linux	BenchmarkDefer	45.880 ns/op	-18.5% (better)
Linux	BenchmarkDirectCall	1.557 ns/op	-0.4% (better)
Linux	BenchmarkGlobalRead	1.871 ns/op	+19.9% (worse)
Linux	BenchmarkGlobalWrite	2.488 ns/op	-0.2% (better)
Linux	BenchmarkGoroutine	32587 ns/op	-56.9% (better)
Linux	BenchmarkInterfaceCall	8.116 ns/op	+4.1% (worse)
Linux	BenchmarkRuntimeGetG	1.868 ns/op	-64.8% (better)
macOS	BenchmarkLookupPCRandom	11.010 ns/op	-11.5% (better)
macOS	BenchmarkMergeCompilerFlags	99.900 ns/op	-19.8% (better)
macOS	BenchmarkMergeLinkerFlags	65.770 ns/op	-5.2% (better)
macOS	BenchmarkChannelBuffered	23.410 ns/op	-15.6% (better)
macOS	BenchmarkChannelHandoff	5312 ns/op	-24.2% (better)
macOS	BenchmarkDefer	27.480 ns/op	-26.6% (better)
macOS	BenchmarkDirectCall	0.942 ns/op	-35.2% (better)
macOS	BenchmarkGlobalRead	0.946 ns/op	-21.9% (better)
macOS	BenchmarkGlobalWrite	0.941 ns/op	-36.7% (better)
macOS	BenchmarkGoroutine	23190 ns/op	-26.7% (better)
macOS	BenchmarkInterfaceCall	4.519 ns/op	-16.3% (better)
macOS	BenchmarkRuntimeGetG	2.115 ns/op	-17.9% (better)

Compared only with the latest matching platform in the main series.

Warning

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