pkg/symbolizer: use llvm-addr2line

Use llvm-addr2line instead of addr2line if it's available.
llvm-addr2line seems to be way faster than llvm-addr2line
and consumes less memory on syzbot's vmlinux.
Also move the detection logic to sys/targets since that's
where we generally do this type of logic. This also allows
to reuse addr2line binary in other packages if needed.

1 files changed, 48 insertions, 0 deletions

diff --git a/sys/targets/targets.go b/sys/targets/targets.go
index 9a5c82948..d7488fcb5 100644
--- a/sys/targets/targets.go
+++ b/sys/targets/targets.go
@@ -4,6 +4,7 @@
 package targets
 
 import (
+	"bytes"
 	"encoding/binary"
 	"fmt"
 	"os"
@@ -38,6 +39,7 @@ type Target struct {
 	NeedSyscallDefine  func(nr uint64) bool
 	HostEndian         binary.ByteOrder
 	SyscallTrampolines map[string]string
+	Addr2Line          func() (string, error)
 
 	init      *sync.Once
 	initOther *sync.Once
@@ -775,6 +777,52 @@ func initTarget(target *Target, OS, arch string) {
 		target.ExecutorUsesForkServer = false
 		target.HostFuzzer = true
 	}
+	target.initAddr2Line()
+}
+
+func (target *Target) initAddr2Line() {
+	// Initialize addr2line lazily since lots of tests don't need it,
+	// but we invoke a number of external binaries during addr2line detection.
+	var (
+		init sync.Once
+		bin  string
+		err  error
+	)
+	target.Addr2Line = func() (string, error) {
+		init.Do(func() { bin, err = target.findAddr2Line() })
+		return bin, err
+	}
+}
+
+func (target *Target) findAddr2Line() (string, error) {
+	// Try llvm-addr2line first as it's significantly faster on large binaries.
+	// But it's unclear if it works for darwin binaries.
+	if target.OS != Darwin {
+		if path, err := exec.LookPath("llvm-addr2line"); err == nil {
+			return path, nil
+		}
+	}
+	bin := "addr2line"
+	if target.Triple != "" {
+		bin = target.Triple + "-" + bin
+	}
+	if target.OS != Darwin || target.Arch != AMD64 {
+		return bin, nil
+	}
+	// A special check for darwin kernel to produce a more useful error.
+	cmd := exec.Command(bin, "--help")
+	cmd.Env = append(os.Environ(), "LC_ALL=C")
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		return "", fmt.Errorf("addr2line execution failed: %w", err)
+	}
+	if !bytes.Contains(out, []byte("supported targets:")) {
+		return "", fmt.Errorf("addr2line output didn't contain supported targets")
+	}
+	if !bytes.Contains(out, []byte("mach-o-x86-64")) {
+		return "", fmt.Errorf("addr2line was built without mach-o-x86-64 support")
+	}
+	return bin, nil
 }
 
 func (target *Target) Timeouts(slowdown int) Timeouts {