invoking the C compiler to compile the C parts of the package.

The following options are available when running cgo directly:

	-V
		Print cgo version and exit.
	-debug-define
		Debugging option. Print #defines.
	-debug-gcc
		Debugging option. Trace C compiler execution and output.
	-dynimport file
		Write list of symbols imported by file. Write to
		-dynout argument or to standard output. Used by go

							return;
						}
						const toCopy = src.subarray(0, dst.length);
						dst.set(toCopy);
						setInt64(sp + 40, toCopy.length);
						this.mem.setUint8(sp + 48, 1);
					},

					"debug": (value) => {
						console.log(value);
					},
				}
			};
		}

		async run(instance) {
			if (!(instance instanceof WebAssembly.Instance)) {

can include one or more `//go:debug` directives at the top of the file
(preceding the `package` statement).
Continuing the `panicnil` example, if the module or workspace is updated
to say `go` `1.21`, the program can opt back into the old `panic(nil)`
behavior by including this directive:

	//go:debug panicnil=1

Starting in Go 1.21, the Go toolchain treats a `//go:debug` directive

pkg debug/buildinfo, func Read(io.ReaderAt) (*debug.BuildInfo, error)
pkg debug/buildinfo, func ReadFile(string) (*debug.BuildInfo, error)
pkg debug/buildinfo, type BuildInfo = debug.BuildInfo
pkg debug/dwarf, type BasicType struct, DataBitOffset int64
pkg debug/dwarf, type StructField struct, DataBitOffset int64
pkg debug/elf, const R_PPC64_RELATIVE = 22
pkg debug/elf, const R_PPC64_RELATIVE R_PPC64

pkg debug/elf, const R_LARCH_ABS_LO12 = 68 #54222
pkg debug/elf, const R_LARCH_ABS_LO12 R_LARCH #54222
pkg debug/elf, const R_LARCH_B16 = 64 #54222
pkg debug/elf, const R_LARCH_B16 R_LARCH #54222
pkg debug/elf, const R_LARCH_B21 = 65 #54222
pkg debug/elf, const R_LARCH_B21 R_LARCH #54222
pkg debug/elf, const R_LARCH_B26 = 66 #54222
pkg debug/elf, const R_LARCH_B26 R_LARCH #54222
pkg debug/elf, const R_LARCH_GNU_VTENTRY = 58 #54222

	if symName != funcName {
		t.Fatalf("expected function name %v; got %v", symName, funcName)
	}
	fi1, err := os.Stat("addr2line_test.go")
	if err != nil {
		t.Fatalf("Stat failed: %v", err)
	}

	// Debug paths are stored slash-separated, so convert to system-native.
	srcPath = filepath.FromSlash(srcPath)
	fi2, err := os.Stat(srcPath)

	if err != nil {
		t.Fatalf("Stat failed: %v", err)
	}

pkg debug/elf, const DT_CONFIG = 1879047930
pkg debug/elf, const DT_CONFIG DynTag
pkg debug/elf, const DT_DEPAUDIT = 1879047931
pkg debug/elf, const DT_DEPAUDIT DynTag
pkg debug/elf, const DT_FEATURE = 1879047676
pkg debug/elf, const DT_FEATURE DynTag
pkg debug/elf, const DT_FILTER = 2147483647
pkg debug/elf, const DT_FILTER DynTag
pkg debug/elf, const DT_FLAGS_1 = 1879048187
pkg debug/elf, const DT_FLAGS_1 DynTag

	if architecture == nil {
		log.Fatalf("unrecognized architecture %s", GOARCH)
	}
	ctxt := obj.Linknew(architecture.LinkArch)
	ctxt.Debugasm = flags.PrintOut
	ctxt.Debugvlog = flags.DebugV
	ctxt.Flag_dynlink = *flags.Dynlink
	ctxt.Flag_linkshared = *flags.Linkshared
	ctxt.Flag_shared = *flags.Shared || *flags.Dynlink
	ctxt.Flag_maymorestack = flags.DebugFlags.MayMoreStack

pkg debug/dwarf, const AttrDefaulted = 139
pkg debug/dwarf, const AttrDefaulted Attr
pkg debug/dwarf, const AttrDeleted = 138
pkg debug/dwarf, const AttrDeleted Attr
pkg debug/dwarf, const AttrDigitCount = 95
pkg debug/dwarf, const AttrDigitCount Attr
pkg debug/dwarf, const AttrDwoName = 118
pkg debug/dwarf, const AttrDwoName Attr
pkg debug/dwarf, const AttrElemental = 102
pkg debug/dwarf, const AttrElemental Attr

// to generate a separate build ID for each package using cgo, and the
// linker concatenated them all.  We don't want that--we only want
// one.

import (
	"bytes"
	"debug/elf"
	"os"
	"testing"
)

func testBuildID(t *testing.T) {
	f, err := elf.Open("/proc/self/exe")
	if err != nil {
		if os.IsNotExist(err) {
			t.Skip("no /proc/self/exe")
		}