Use external red/black tree package

dwarf/frame/frame_entries.go

@@ -1,6 +1,10 @@
 package frame
 
-import "fmt"
+import (
+	"fmt"
+
+	"github.com/derekparker/rbtree"
+)
 
 // Represents a Common Information Entry in
 // the Dwarf .debug_frame section.
@@ -54,112 +58,40 @@ func (fde *FrameDescriptionEntry) ReturnAddressOffset(pc uint64) int64 {
 	return frame.cfa.offset + frame.regs[fde.CIE.ReturnAddressRegister].offset
 }
 
-const (
-	RED   = true
-	BLACK = false
-)
-
 type FrameDescriptionEntries struct {
-	root *FrameNode
-}
-
-type FrameNode struct {
-	entry       *FrameDescriptionEntry
-	left, right *FrameNode
-	color       bool
+	*rbtree.RedBlackTree
 }
 
 func NewFrameIndex() *FrameDescriptionEntries {
-	return &FrameDescriptionEntries{}
+	return &FrameDescriptionEntries{rbtree.New()}
 }
 
-func (fs *FrameDescriptionEntries) Find(pc uint64) (*FrameDescriptionEntry, bool) {
-	return find(fs.root, pc)
-}
-
-func find(fn *FrameNode, pc uint64) (*FrameDescriptionEntry, bool) {
-	switch {
-	case fn == nil:
-		return nil, false
-	case fn.entry.AddressRange.Cover(pc):
-		return fn.entry, true
-	case pc < fn.entry.AddressRange.begin:
-		return find(fn.left, pc)
-	case pc > fn.entry.AddressRange.begin+fn.entry.AddressRange.end:
-		return find(fn.right, pc)
-	}
-
-	return nil, false
-}
-
-func (fs *FrameDescriptionEntries) Put(entry *FrameDescriptionEntry) {
-	fs.root = put(fs.root, entry)
-	fs.root.color = BLACK
-}
-
-func put(fn *FrameNode, entry *FrameDescriptionEntry) *FrameNode {
-	switch {
-	case fn == nil:
-		return &FrameNode{entry: entry, color: RED}
-	case entry.AddressRange.begin < fn.entry.AddressRange.begin:
-		fn.left = put(fn.left, entry)
-	case entry.AddressRange.begin > fn.entry.AddressRange.begin:
-		fn.right = put(fn.right, entry)
-	}
-
-	leftRed := isRed(fn.left)
-	rightRed := isRed(fn.right)
-
-	if !leftRed && rightRed {
-		fn = rotateLeft(fn)
-	} else if leftRed && isRed(fn.left.left) {
-		fn = rotateRight(fn)
-	}
-
-	if leftRed && rightRed {
-		fn.left.color = BLACK
-		fn.right.color = BLACK
-		fn.color = RED
-	}
-
-	return fn
-}
-
-func isRed(fn *FrameNode) bool {
-	if fn == nil {
-		return false
-	}
-
-	return fn.color
-}
-
-func rotateLeft(fn *FrameNode) *FrameNode {
-	x := fn.right
-	fn.right = x.left
-	x.left = fn
-
-	x.color = fn.color
-	fn.color = RED
-
-	return x
-}
-
-func rotateRight(fn *FrameNode) *FrameNode {
-	x := fn.left
-	fn.left = x.right
-	x.right = fn
-
-	x.color = fn.color
-	fn.color = RED
-
-	return x
-}
-
-func (fdes FrameDescriptionEntries) FDEForPC(pc uint64) (*FrameDescriptionEntry, error) {
-	fde, ok := fdes.Find(pc)
+func (fdes *FrameDescriptionEntries) FDEForPC(pc uint64) (*FrameDescriptionEntry, error) {
+	node, ok := fdes.Find(Addr(pc))
 	if !ok {
 		return nil, fmt.Errorf("Could not find FDE for %#v", pc)
 	}
 
-	return fde, nil
+	return node.(*FrameDescriptionEntry), nil
+}
+
+func (frame *FrameDescriptionEntry) Less(item rbtree.Item) bool {
+	return frame.AddressRange.begin < item.(*FrameDescriptionEntry).AddressRange.begin
+}
+
+func (frame *FrameDescriptionEntry) More(item rbtree.Item) bool {
+	r := item.(*FrameDescriptionEntry).AddressRange
+	fnr := frame.AddressRange
+	return fnr.begin+fnr.end > r.begin+r.end
+}
+
+type Addr uint64
+
+func (a Addr) Less(item rbtree.Item) bool {
+	return uint64(a) < item.(*FrameDescriptionEntry).AddressRange.begin
+}
+
+func (a Addr) More(item rbtree.Item) bool {
+	r := item.(*FrameDescriptionEntry).AddressRange
+	return uint64(a) > r.begin+r.end
 }

dwarf/frame/frame_entries_test.go

@@ -19,12 +19,12 @@ func TestFDEForPC(t *testing.T) {
 	tree.Put(fde3)
 	tree.Put(fde4)
 
-	fde, ok := tree.Find(35)
+	node, ok := tree.Find(Addr(35))
 	if !ok {
 		t.Fatal("Could not find FDE")
 	}
 
-	if fde != fde3 {
+	if node != fde3 {
 		t.Fatal("Got incorrect fde")
 	}
 }

dwarf/frame/frame_parser.go

@@ -14,7 +14,7 @@ type parsefunc func(*parseContext) parsefunc
 
 type parseContext struct {
 	Buf     *bytes.Buffer
-	Entries FrameDescriptionEntries
+	Entries *FrameDescriptionEntries
 	Common  *CommonInformationEntry
 	Frame   *FrameDescriptionEntry
 	Length  uint32
@@ -23,10 +23,10 @@ type parseContext struct {
 // Parse takes in data (a byte slice) and returns a slice of
 // CommonInformationEntry structures. Each CommonInformationEntry
 // has a slice of FrameDescriptionEntry structures.
-func Parse(data []byte) FrameDescriptionEntries {
+func Parse(data []byte) *FrameDescriptionEntries {
 	var (
 		buf  = bytes.NewBuffer(data)
-		pctx = &parseContext{Buf: buf}
+		pctx = &parseContext{Buf: buf, Entries: NewFrameIndex()}
 	)
 
 	for fn := parseLength; buf.Len() != 0; {

proctl/proctl_linux_amd64.go

@@ -30,7 +30,7 @@ type DebuggedProcess struct {
 	Executable      *elf.File
 	Symbols         []elf.Symbol
 	GoSymTable      *gosym.Table
-	FrameEntries    frame.FrameDescriptionEntries
+	FrameEntries    *frame.FrameDescriptionEntries
 	DebugLine       *line.DebugLineInfo
 	BreakPoints     map[string]*BreakPoint
 	TempBreakPoints map[uint64]*BreakPoint