feat(proc, stub): expose GetMarkStubAddr API to scan and record memory partially by intrusively insert stub address in struct definition

cmd/grf/cmds/commands.go

@@ -41,6 +41,9 @@ var (
 
 	// verbose is whether to log verbose info, like debug logs.
 	verbose bool
+
+	// useMarkStub is whether to use mark stub for object reference analysis.
+	useMarkStub bool
 )
 
 // New returns an initialized command tree.
@@ -75,6 +78,7 @@ You'll have to wait for goref until it outputs 'successfully output to ...', or
 	}
 	attachCommand.Flags().IntVar(&maxRefDepth, "max-depth", 0, "max reference depth shown by pprof")
 	attachCommand.Flags().StringVarP(&outFile, "out", "o", "grf.out", "output file name")
+	attachCommand.Flags().BoolVar(&useMarkStub, "usemarkstub", false, "use mark stub for partial object reference analysis")
 	rootCommand.AddCommand(attachCommand)
 
 	coreCommand := &cobra.Command{
@@ -130,14 +134,14 @@ func attachCmd(_ *cobra.Command, args []string) {
 	if len(args) > 1 {
 		exeFile = args[1]
 	}
-	os.Exit(execute(pid, exeFile, "", outFile, conf))
+	os.Exit(execute(pid, exeFile, "", outFile, useMarkStub, conf))
 }
 
 func coreCmd(_ *cobra.Command, args []string) {
-	os.Exit(execute(0, args[0], args[1], outFile, conf))
+	os.Exit(execute(0, args[0], args[1], outFile, useMarkStub, conf))
 }
 
-func execute(attachPid int, exeFile, coreFile, outFile string, conf *config.Config) int {
+func execute(attachPid int, exeFile, coreFile, outFile string, useMarkStub bool, conf *config.Config) int {
 	if verbose {
 		if err := logflags.Setup(verbose, "", ""); err != nil {
 			fmt.Fprintf(os.Stderr, "%v\n", err)
@@ -175,7 +179,7 @@ func execute(attachPid int, exeFile, coreFile, outFile string, conf *config.Conf
 	func() {
 		tg, unlock := dbg.LockTargetGroup()
 		defer unlock()
-		_, err = myproc.ObjectReference(tg.Selected, outFile)
+		_, err = myproc.ObjectReference(tg.Selected, outFile, useMarkStub)
 	}()
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err.Error())

cmd/grf/cmds/self_attach.go

@@ -0,0 +1,27 @@
+package cmds
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"runtime"
+	"strconv"
+)
+
+// AttachSelf create new grf process to attach to caller's pid
+func AttachSelf(filename string) error {
+	// check grf first
+	binName := "grf"
+	if runtime.GOOS == "windows" {
+		binName = "grf.exe"
+	}
+
+	grfPath, err := exec.LookPath(binName)
+	if err != nil {
+		return fmt.Errorf("grf not found in PATH: %v", err)
+	}
+
+	// execute grf
+	cmd := exec.Command(grfPath, "attach", strconv.Itoa(os.Getpid()), "-o", filename)
+	return cmd.Run()
+}

pkg/proc/heap.go

@@ -165,6 +165,8 @@ type HeapScope struct {
 	greenTeaGCEnabled      bool
 	spanInlineMarkBitsSize int64
 	inlineMarkSpanPages    map[Address]struct{}
+	// stub address
+	markStubAddr Address // address for pkg/stub.markStub
 }
 
 func (s *HeapScope) readHeap() error {
@@ -422,7 +424,7 @@ func (s *HeapScope) readBitmapFunc(heapArena *region) func(heapArena *region, mi
 	}
 }
 
-// base must be the base address of an object in then span
+// base must be the base address of an object in the span
 func (s *HeapScope) copyGCMask(sp *spanInfo, base Address) Address {
 	if !s.enableAllocHeader {
 		return base
@@ -866,3 +868,13 @@ func (s *HeapScope) rtConstant(name string) int64 {
 	}
 	return 0
 }
+
+func (s *HeapScope) readMarkStubAddr() error {
+	tmp, err := s.scope.EvalExpression("stub.markStub", loadSingleValue)
+	if err != nil {
+		return err
+	}
+	markStub := toRegion(tmp, s.bi)
+	s.markStubAddr = markStub.a
+	return nil
+}