proc: address PR review feedback for non-Go binary debugging

- Deduplicate auxv parsing by extracting searchAuxv helper
- Rename IsNonGo to IsGo (positive flag is easier to reason about)
- Move Go image detection into loadDebugInfoMaps to avoid reparsing
  debug_info; uses DW_AT_language == DW_LANG_Go which is already
  checked there for cu.isgo
- Remove hasGoProducer function (no longer needed)
- Remove pkg/proc import from pkg/terminal/command.go; use string
  literal for stop reason comparison instead
- Update CLAUDE.md with DWARF parsing and layer boundary guidance

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: derekparker

CLAUDE.md

@@ -282,6 +282,10 @@ Fixes #1234
 4. **Memory safety** - Always handle errors when reading process memory.
    Process may die, memory may be unmapped, or addresses invalid.
 
+5. **Don't reparse DWARF sections** - `loadDebugInfoMaps` already
+   iterates all compile units. Add per-CU checks there instead of
+   making separate passes over `debug_info`.
+
 ## File Organization
 
 ```

pkg/proc/bininfo.go

@@ -1023,9 +1023,9 @@ type Image struct {
 	symTable *gosym.Table
 	Trimpath bool // trimpath used
 
-	// IsNonGo is true when the image has been confirmed to not be a Go binary.
-	// This is set when both DWARF loading and Go runtime symbol table loading fail.
-	IsNonGo bool
+	// IsGo is true when the image has been confirmed to be a Go binary,
+	// e.g. by checking for a Go producer string in DWARF compile units.
+	IsGo bool
 
 	typeCache map[dwarf.Offset]godwarf.Type
 
@@ -1060,7 +1060,7 @@ func (image *Image) Stripped() bool {
 // successfully loaded debug info.
 func (bi *BinaryInfo) HasGoImage() bool {
 	for _, image := range bi.Images {
-		if !image.IsNonGo && image.loadErr == nil {
+		if image.IsGo && image.loadErr == nil {
 			return true
 		}
 	}
@@ -1446,27 +1446,6 @@ func (bi *Image) findCompileUnitForOffset(off dwarf.Offset) *compileUnit {
 	return bi.compileUnits[i]
 }
 
-// hasGoProducer reports whether d contains any compilation unit with a Go
-// producer string (DW_AT_producer starting with "Go "). This is used during
-// image loading to distinguish Go binaries from non-Go binaries that happen
-// to have DWARF debug info.
-func hasGoProducer(d *dwarf.Data) bool {
-	reader := d.Reader()
-	for {
-		entry, err := reader.Next()
-		if err != nil || entry == nil {
-			return false
-		}
-		if entry.Tag == dwarf.TagCompileUnit {
-			producer, _ := entry.Val(dwarf.AttrProducer).(string)
-			if strings.HasPrefix(producer, "Go ") {
-				return true
-			}
-			reader.SkipChildren()
-		}
-	}
-}
-
 // Producer returns the value of DW_AT_producer.
 func (bi *BinaryInfo) Producer() string {
 	for _, cu := range bi.Images[0].compileUnits {
@@ -1737,9 +1716,9 @@ func loadBinaryInfoElf(bi *BinaryInfo, image *Image, path string, addr uint64, w
 			}
 			err := loadBinaryInfoGoRuntimeElf(bi, image, path, elfFile)
 			if err != nil {
-				image.IsNonGo = true
 				return fmt.Errorf("could not read debug info (%v) and could not read go symbol table (%v)", dwerr, err)
 			}
+			image.IsGo = true
 			return nil
 		}
 		image.sepDebugCloser = sepFile
@@ -1749,14 +1728,6 @@ func loadBinaryInfoElf(bi *BinaryInfo, image *Image, path string, addr uint64, w
 		}
 	}
 
-	// Mark images that have DWARF but no Go producer string as non-Go.
-	// Without this check, shared libraries that have DWARF debug info would
-	// be incorrectly treated as Go images by HasGoImage(), since IsNonGo is
-	// only set when both DWARF and Go symbol table loading fail.
-	if !hasGoProducer(image.dwarf) {
-		image.IsNonGo = true
-	}
-
 	debugInfoBytes, err = godwarf.GetDebugSectionElf(dwarfFile, "info")
 	if err != nil {
 		return err
@@ -2650,6 +2621,7 @@ func (bi *BinaryInfo) loadDebugInfoMaps(image *Image, debugInfoBytes, debugLineB
 			cu.Version = ctxt.offsetToVersion[cu.offset]
 			if lang, _ := entry.Val(dwarf.AttrLanguage).(int64); lang == dwarfGoLanguage {
 				cu.isgo = true
+				image.IsGo = true
 			}
 			cu.name, _ = entry.Val(dwarf.AttrName).(string)
 			compdir, _ := entry.Val(dwarf.AttrCompDir).(string)

pkg/proc/linutil/auxv.go

@@ -11,38 +11,14 @@ const (
 	_AT_ENTRY = 9
 )
 
-// BaseFromAuxv searches the elf auxiliary vector for the AT_BASE value,
-// which is the base address of the dynamic linker (interpreter).
-func BaseFromAuxv(auxv []byte, ptrSize int) uint64 {
-	rd := bytes.NewBuffer(auxv)
-
-	for {
-		tag, err := readUintRaw(rd, binary.LittleEndian, ptrSize)
-		if err != nil {
-			return 0
-		}
-		val, err := readUintRaw(rd, binary.LittleEndian, ptrSize)
-		if err != nil {
-			return 0
-		}
-
-		switch tag {
-		case _AT_NULL:
-			return 0
-		case _AT_BASE:
-			return val
-		}
-	}
-}
-
-// EntryPointFromAuxv searches the elf auxiliary vector for the entry point
-// address.
+// searchAuxv searches the elf auxiliary vector for the given tag and returns
+// its value. Returns 0 if the tag is not found.
 // For a description of the auxiliary vector (auxv) format see:
 // System V Application Binary Interface, AMD64 Architecture Processor
 // Supplement, section 3.4.3.
 // System V Application Binary Interface, Intel386 Architecture Processor
 // Supplement (fourth edition), section 3-28.
-func EntryPointFromAuxv(auxv []byte, ptrSize int) uint64 {
+func searchAuxv(auxv []byte, ptrSize int, target uint64) uint64 {
 	rd := bytes.NewBuffer(auxv)
 
 	for {
@@ -58,8 +34,20 @@ func EntryPointFromAuxv(auxv []byte, ptrSize int) uint64 {
 		switch tag {
 		case _AT_NULL:
 			return 0
-		case _AT_ENTRY:
+		case target:
 			return val
 		}
 	}
 }
+
+// BaseFromAuxv searches the elf auxiliary vector for the AT_BASE value,
+// which is the base address of the dynamic linker (interpreter).
+func BaseFromAuxv(auxv []byte, ptrSize int) uint64 {
+	return searchAuxv(auxv, ptrSize, _AT_BASE)
+}
+
+// EntryPointFromAuxv searches the elf auxiliary vector for the entry point
+// address.
+func EntryPointFromAuxv(auxv []byte, ptrSize int) uint64 {
+	return searchAuxv(auxv, ptrSize, _AT_ENTRY)
+}

pkg/proc/native/proc.go

@@ -388,7 +388,7 @@ func (dbp *nativeProcess) initialize(path string, debugInfoDirs []string) (*proc
 		return nil, err
 	}
 	if dbp.bi.Arch.Name == "arm64" || dbp.bi.Arch.Name == "ppc64le" || dbp.bi.Arch.Name == "riscv64" || dbp.bi.Arch.Name == "loong64" {
-		if len(dbp.bi.Images) > 0 && !dbp.bi.Images[0].IsNonGo {
+		if len(dbp.bi.Images) > 0 && dbp.bi.Images[0].IsGo {
 			dbp.iscgo = tgt.IsCgo()
 		}
 	}

pkg/proc/native/proc_linux.go

@@ -187,7 +187,7 @@ func setupSharedLibBreakpoint(dbp *nativeProcess, grp *proc.TargetGroup) {
 		return
 	}
 	bi := grp.Selected.BinInfo()
-	if len(bi.Images) == 0 || !bi.Images[0].IsNonGo {
+	if len(bi.Images) == 0 || bi.Images[0].IsGo {
 		return
 	}
 	rBrkAddr, err := linutil.ElfFindRBrk(grp.Selected)

pkg/proc/proc_test.go

@@ -6090,8 +6090,8 @@ func TestNonGoBinaryWithGoDlopen(t *testing.T) {
 	if len(p.BinInfo().Images) == 0 {
 		t.Fatal("no images loaded")
 	}
-	if !p.BinInfo().Images[0].IsNonGo {
-		t.Error("expected Images[0].IsNonGo to be true")
+	if p.BinInfo().Images[0].IsGo {
+		t.Error("expected Images[0].IsGo to be false")
 	}
 	if p.BinInfo().HasGoImage() {
 		t.Error("expected HasGoImage to be false before dlopen")

pkg/proc/target.go

@@ -183,14 +183,14 @@ func (grp *TargetGroup) newTarget(p ProcessInternal, pid int, currentThread Thre
 	if err != nil {
 		// If this is a non-Go binary, log a warning and continue.
 		// A Go shared object may be loaded later via dlopen.
-		if len(p.BinInfo().Images) > 0 && p.BinInfo().Images[0].IsNonGo {
+		if len(p.BinInfo().Images) > 0 && !p.BinInfo().Images[0].IsGo {
 			logflags.DebuggerLogger().Warnf("Initial binary is not a Go binary: %v", err)
 		} else {
 			return nil, &ErrBadBinaryInfo{Err: err}
 		}
 	}
 	for _, image := range p.BinInfo().Images {
-		if image.loadErr != nil && !image.IsNonGo {
+		if image.loadErr != nil && image.IsGo {
 			return nil, &ErrBadBinaryInfo{Err: image.loadErr}
 		}
 	}

pkg/terminal/command.go

@@ -30,7 +30,6 @@ import (
 	"github.com/cosiner/argv"
 	"github.com/go-delve/delve/pkg/config"
 	"github.com/go-delve/delve/pkg/locspec"
-	"github.com/go-delve/delve/pkg/proc"
 	"github.com/go-delve/delve/pkg/proc/debuginfod"
 	"github.com/go-delve/delve/service"
 	"github.com/go-delve/delve/service/api"
@@ -2798,7 +2797,7 @@ func printcontext(t *Term, state *api.DebuggerState) {
 		return
 	}
 
-	if state.StopReason == proc.StopSharedLibLoaded.String() {
+	if state.StopReason == "shared library loaded" {
 		fmt.Fprintln(t.stdout, "Go shared library loaded. You can now set breakpoints in Go code.")
 	}