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refactor(debug): move watchpoint slot state into the session

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petrbalvin
2026-09-14 18:22:00 +02:00
parent 909f874797
commit 4f190ee1a2
7 changed files with 38 additions and 51 deletions
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debug/breakpoint.go
+4 -5
View File
@@ -36,7 +36,7 @@ type Condition struct {
func (c *Condition) Eval(regs *Regs) bool { func (c *Condition) Eval(regs *Regs) bool {
actual, ok := regs.RegValue(c.Reg) actual, ok := regs.RegValue(c.Reg)
if !ok { if !ok {
return true // unknown register — don't block return true // unknown register, don't block
} }
var expected uint64 var expected uint64
switch { switch {
@@ -48,7 +48,7 @@ func (c *Condition) Eval(regs *Regs) bool {
} }
expected = v expected = v
case c.MemAddr != 0: case c.MemAddr != 0:
// Register-memory comparison — requires a Session, not available here. // Register-memory comparison, requires a Session, not available here.
// Fall back to treating as constant (the caller should resolve). // Fall back to treating as constant (the caller should resolve).
expected = c.Value expected = c.Value
default: default:
@@ -72,8 +72,7 @@ func (c *Condition) Eval(regs *Regs) bool {
} }
} }
// Breakpoints manages the set of breakpoints for a Session. // Breakpoints manages the software breakpoints of one Session.
// Breakpoints manages software breakpoints for a debuggee.
type Breakpoints struct { type Breakpoints struct {
t tracer t tracer
bps map[uint64]*Breakpoint bps map[uint64]*Breakpoint
@@ -200,7 +199,7 @@ func (bm *Breakpoints) HandleTrap(regs *Regs) *Breakpoint {
} }
// Check the condition (if any). // Check the condition (if any).
if bp.Cond != nil && !bp.Cond.Eval(regs) { if bp.Cond != nil && !bp.Cond.Eval(regs) {
// Condition not met — restore the byte but do NOT rewind RIP. // Condition not met, restore the byte but do NOT rewind RIP.
// The process continues from the next instruction (past the INT3). // The process continues from the next instruction (past the INT3).
word, err := bm.t.Peek(trapAddr) word, err := bm.t.Peek(trapAddr)
if err == nil { if err == nil {
debug/debug_test.go
+4 -5
View File
@@ -275,8 +275,7 @@ func TestBreakpointInfo(t *testing.T) {
} }
func TestWatchpointSlotTracking(t *testing.T) { func TestWatchpointSlotTracking(t *testing.T) {
wpSlots = [4]bool{} // reset s := &Session{} // per-session slots start free
s := &Session{}
// All four slots are free initially. // All four slots are free initially.
for i := range 4 { for i := range 4 {
@@ -289,8 +288,8 @@ func TestWatchpointSlotTracking(t *testing.T) {
} }
// Manually mark slots 0 and 2 as used (simulating successful SetWatchpoint). // Manually mark slots 0 and 2 as used (simulating successful SetWatchpoint).
wpSlots[0] = true s.wpSlots[0] = true
wpSlots[2] = true s.wpSlots[2] = true
if !s.IsWatchpointSlotUsed(0) { if !s.IsWatchpointSlotUsed(0) {
t.Error("slot 0 should be in use") t.Error("slot 0 should be in use")
@@ -318,7 +317,7 @@ func TestWatchpointSlotTracking(t *testing.T) {
// Mark all slots used: FindFreeWatchpointSlot returns -1. // Mark all slots used: FindFreeWatchpointSlot returns -1.
for i := range 4 { for i := range 4 {
wpSlots[i] = true s.wpSlots[i] = true
} }
if got := s.FindFreeWatchpointSlot(); got != -1 { if got := s.FindFreeWatchpointSlot(); got != -1 {
t.Errorf("FindFreeWatchpointSlot() with all slots used = %d, want -1", got) t.Errorf("FindFreeWatchpointSlot() with all slots used = %d, want -1", got)
debug/ptrace_linux.go
+2 -1
View File
@@ -22,7 +22,8 @@ type Session struct {
cmd *exec.Cmd cmd *exec.Cmd
stopped bool stopped bool
exited bool exited bool
codeBase uint64 // base address of the JIT code in the debuggee codeBase uint64 // base address of the JIT code in the debuggee
wpSlots [16]bool // hardware watchpoint slots in use (DR0-DR3, arm64 BADVR0-15)
} }
// Launch starts the debuggee subprocess (gasm debug --target ...) and // Launch starts the debuggee subprocess (gasm debug --target ...) and
debug/watchpoint_linux_amd64.go
+7 -10
View File
@@ -20,14 +20,11 @@ const (
WatchRead WatchpointType = 3 // trigger on read or write WatchRead WatchpointType = 3 // trigger on read or write
) )
// wpSlots tracks watchpoint slot occupancy (DR0-DR3).
var wpSlots [4]bool
// FindFreeWatchpointSlot returns the index of the first free watchpoint slot // FindFreeWatchpointSlot returns the index of the first free watchpoint slot
// (0-3), or -1 if all four hardware watchpoints are in use. // (0-3), or -1 if all four hardware watchpoints are in use.
func (s *Session) FindFreeWatchpointSlot() int { func (s *Session) FindFreeWatchpointSlot() int {
for i := range 4 { for i := range 4 {
if !wpSlots[i] { if !s.wpSlots[i] {
return i return i
} }
} }
@@ -39,7 +36,7 @@ func (s *Session) IsWatchpointSlotUsed(slot int) bool {
if slot < 0 || slot > 3 { if slot < 0 || slot > 3 {
return false return false
} }
return wpSlots[slot] return s.wpSlots[slot]
} }
// SetWatchpoint installs a hardware watchpoint on the given address. // SetWatchpoint installs a hardware watchpoint on the given address.
@@ -47,7 +44,7 @@ func (s *Session) SetWatchpoint(slot int, addr uint64, typ WatchpointType, size
if slot < 0 || slot > 3 { if slot < 0 || slot > 3 {
return fmt.Errorf("debug: watchpoint slot must be 0-3") return fmt.Errorf("debug: watchpoint slot must be 0-3")
} }
if wpSlots[slot] { if s.wpSlots[slot] {
return fmt.Errorf("debug: watchpoint slot %d already in use", slot) return fmt.Errorf("debug: watchpoint slot %d already in use", slot)
} }
@@ -96,7 +93,7 @@ func (s *Session) SetWatchpoint(slot int, addr uint64, typ WatchpointType, size
if err := ptracePokeUser(s.pid, 0x38, dr7); err != nil { if err := ptracePokeUser(s.pid, 0x38, dr7); err != nil {
return fmt.Errorf("debug: set DR7: %w", err) return fmt.Errorf("debug: set DR7: %w", err)
} }
wpSlots[slot] = true s.wpSlots[slot] = true
return nil return nil
} }
@@ -105,7 +102,7 @@ func (s *Session) ClearWatchpoint(slot int) error {
if slot < 0 || slot > 3 { if slot < 0 || slot > 3 {
return fmt.Errorf("debug: watchpoint slot must be 0-3") return fmt.Errorf("debug: watchpoint slot must be 0-3")
} }
if !wpSlots[slot] { if !s.wpSlots[slot] {
return fmt.Errorf("debug: watchpoint slot %d is not in use", slot) return fmt.Errorf("debug: watchpoint slot %d is not in use", slot)
} }
dr7, err := ptracePeekUser(s.pid, 0x38) dr7, err := ptracePeekUser(s.pid, 0x38)
@@ -116,14 +113,14 @@ func (s *Session) ClearWatchpoint(slot int) error {
if err := ptracePokeUser(s.pid, 0x38, dr7); err != nil { if err := ptracePokeUser(s.pid, 0x38, dr7); err != nil {
return err return err
} }
wpSlots[slot] = false s.wpSlots[slot] = false
return nil return nil
} }
// ClearAllWatchpoints removes all hardware watchpoints. // ClearAllWatchpoints removes all hardware watchpoints.
func (s *Session) ClearAllWatchpoints() error { func (s *Session) ClearAllWatchpoints() error {
for slot := range 4 { for slot := range 4 {
if wpSlots[slot] { if s.wpSlots[slot] {
if err := s.ClearWatchpoint(slot); err != nil { if err := s.ClearWatchpoint(slot); err != nil {
return err return err
} }
debug/watchpoint_linux_arm64.go
+7 -10
View File
@@ -22,9 +22,6 @@ const (
WatchRead WatchpointType = 3 WatchRead WatchpointType = 3
) )
// wpSlots tracks watchpoint slot occupancy.
var wpSlots [16]bool // arm64 supports up to 16 watchpoints
const maxWatchpoints = 16 const maxWatchpoints = 16
// hwBreakState mirrors the kernel's struct user_hwdebug_state. // hwBreakState mirrors the kernel's struct user_hwdebug_state.
@@ -45,7 +42,7 @@ const (
func (s *Session) FindFreeWatchpointSlot() int { func (s *Session) FindFreeWatchpointSlot() int {
for i := range maxWatchpoints { for i := range maxWatchpoints {
if !wpSlots[i] { if !s.wpSlots[i] {
return i return i
} }
} }
@@ -56,7 +53,7 @@ func (s *Session) IsWatchpointSlotUsed(slot int) bool {
if slot < 0 || slot >= maxWatchpoints { if slot < 0 || slot >= maxWatchpoints {
return false return false
} }
return wpSlots[slot] return s.wpSlots[slot]
} }
// SetWatchpoint installs a hardware watchpoint on the given address. // SetWatchpoint installs a hardware watchpoint on the given address.
@@ -64,7 +61,7 @@ func (s *Session) SetWatchpoint(slot int, addr uint64, typ WatchpointType, size
if slot < 0 || slot >= maxWatchpoints { if slot < 0 || slot >= maxWatchpoints {
return fmt.Errorf("debug: watchpoint slot must be 0-%d", maxWatchpoints-1) return fmt.Errorf("debug: watchpoint slot must be 0-%d", maxWatchpoints-1)
} }
if wpSlots[slot] { if s.wpSlots[slot] {
return fmt.Errorf("debug: watchpoint slot %d already in use", slot) return fmt.Errorf("debug: watchpoint slot %d already in use", slot)
} }
@@ -105,7 +102,7 @@ func (s *Session) SetWatchpoint(slot int, addr uint64, typ WatchpointType, size
return fmt.Errorf("debug: set watchpoint: %w", err) return fmt.Errorf("debug: set watchpoint: %w", err)
} }
wpSlots[slot] = true s.wpSlots[slot] = true
return nil return nil
} }
@@ -113,7 +110,7 @@ func (s *Session) ClearWatchpoint(slot int) error {
if slot < 0 || slot >= maxWatchpoints { if slot < 0 || slot >= maxWatchpoints {
return fmt.Errorf("debug: watchpoint slot must be 0-%d", maxWatchpoints-1) return fmt.Errorf("debug: watchpoint slot must be 0-%d", maxWatchpoints-1)
} }
if !wpSlots[slot] { if !s.wpSlots[slot] {
return fmt.Errorf("debug: watchpoint slot %d is not in use", slot) return fmt.Errorf("debug: watchpoint slot %d is not in use", slot)
} }
@@ -126,13 +123,13 @@ func (s *Session) ClearWatchpoint(slot int) error {
if err := s.setHWBreakState(state); err != nil { if err := s.setHWBreakState(state); err != nil {
return err return err
} }
wpSlots[slot] = false s.wpSlots[slot] = false
return nil return nil
} }
func (s *Session) ClearAllWatchpoints() error { func (s *Session) ClearAllWatchpoints() error {
for slot := 0; slot < maxWatchpoints; slot++ { for slot := 0; slot < maxWatchpoints; slot++ {
if wpSlots[slot] { if s.wpSlots[slot] {
if err := s.ClearWatchpoint(slot); err != nil { if err := s.ClearWatchpoint(slot); err != nil {
return err return err
} }
debug/watchpoint_linux_loong64.go
+7 -10
View File
@@ -21,14 +21,11 @@ const (
WatchRead WatchpointType = 3 WatchRead WatchpointType = 3
) )
// wpSlots tracks watchpoint slot occupancy.
var wpSlots [4]bool
const maxWatchpoints = 4 const maxWatchpoints = 4
func (s *Session) FindFreeWatchpointSlot() int { func (s *Session) FindFreeWatchpointSlot() int {
for i := range maxWatchpoints { for i := range maxWatchpoints {
if !wpSlots[i] { if !s.wpSlots[i] {
return i return i
} }
} }
@@ -39,7 +36,7 @@ func (s *Session) IsWatchpointSlotUsed(slot int) bool {
if slot < 0 || slot >= maxWatchpoints { if slot < 0 || slot >= maxWatchpoints {
return false return false
} }
return wpSlots[slot] return s.wpSlots[slot]
} }
// SetWatchpoint installs a hardware watchpoint. // SetWatchpoint installs a hardware watchpoint.
@@ -47,7 +44,7 @@ func (s *Session) SetWatchpoint(slot int, addr uint64, typ WatchpointType, size
if slot < 0 || slot >= maxWatchpoints { if slot < 0 || slot >= maxWatchpoints {
return fmt.Errorf("debug: watchpoint slot must be 0-%d", maxWatchpoints-1) return fmt.Errorf("debug: watchpoint slot must be 0-%d", maxWatchpoints-1)
} }
if wpSlots[slot] { if s.wpSlots[slot] {
return fmt.Errorf("debug: watchpoint slot %d already in use", slot) return fmt.Errorf("debug: watchpoint slot %d already in use", slot)
} }
if size != 1 && size != 2 && size != 4 && size != 8 { if size != 1 && size != 2 && size != 4 && size != 8 {
@@ -85,7 +82,7 @@ func (s *Session) SetWatchpoint(slot int, addr uint64, typ WatchpointType, size
return fmt.Errorf("debug: set watchpoint control: %w", err) return fmt.Errorf("debug: set watchpoint control: %w", err)
} }
wpSlots[slot] = true s.wpSlots[slot] = true
return nil return nil
} }
@@ -93,20 +90,20 @@ func (s *Session) ClearWatchpoint(slot int) error {
if slot < 0 || slot >= maxWatchpoints { if slot < 0 || slot >= maxWatchpoints {
return fmt.Errorf("debug: watchpoint slot must be 0-%d", maxWatchpoints-1) return fmt.Errorf("debug: watchpoint slot must be 0-%d", maxWatchpoints-1)
} }
if !wpSlots[slot] { if !s.wpSlots[slot] {
return fmt.Errorf("debug: watchpoint slot %d is not in use", slot) return fmt.Errorf("debug: watchpoint slot %d is not in use", slot)
} }
if err := ptracePokeUser(s.pid, uintptr(0x1001+slot*8), 0); err != nil { if err := ptracePokeUser(s.pid, uintptr(0x1001+slot*8), 0); err != nil {
return err return err
} }
wpSlots[slot] = false s.wpSlots[slot] = false
return nil return nil
} }
func (s *Session) ClearAllWatchpoints() error { func (s *Session) ClearAllWatchpoints() error {
for slot := 0; slot < maxWatchpoints; slot++ { for slot := 0; slot < maxWatchpoints; slot++ {
if wpSlots[slot] { if s.wpSlots[slot] {
if err := s.ClearWatchpoint(slot); err != nil { if err := s.ClearWatchpoint(slot); err != nil {
return err return err
} }
debug/watchpoint_linux_riscv64.go
+7 -10
View File
@@ -21,14 +21,11 @@ const (
WatchRead WatchpointType = 3 WatchRead WatchpointType = 3
) )
// wpSlots tracks watchpoint slot occupancy.
var wpSlots [4]bool
const maxWatchpoints = 4 const maxWatchpoints = 4
func (s *Session) FindFreeWatchpointSlot() int { func (s *Session) FindFreeWatchpointSlot() int {
for i := range maxWatchpoints { for i := range maxWatchpoints {
if !wpSlots[i] { if !s.wpSlots[i] {
return i return i
} }
} }
@@ -39,7 +36,7 @@ func (s *Session) IsWatchpointSlotUsed(slot int) bool {
if slot < 0 || slot >= maxWatchpoints { if slot < 0 || slot >= maxWatchpoints {
return false return false
} }
return wpSlots[slot] return s.wpSlots[slot]
} }
// SetWatchpoint installs a hardware watchpoint. // SetWatchpoint installs a hardware watchpoint.
@@ -47,7 +44,7 @@ func (s *Session) SetWatchpoint(slot int, addr uint64, typ WatchpointType, size
if slot < 0 || slot >= maxWatchpoints { if slot < 0 || slot >= maxWatchpoints {
return fmt.Errorf("debug: watchpoint slot must be 0-%d", maxWatchpoints-1) return fmt.Errorf("debug: watchpoint slot must be 0-%d", maxWatchpoints-1)
} }
if wpSlots[slot] { if s.wpSlots[slot] {
return fmt.Errorf("debug: watchpoint slot %d already in use", slot) return fmt.Errorf("debug: watchpoint slot %d already in use", slot)
} }
if size != 1 && size != 2 && size != 4 && size != 8 { if size != 1 && size != 2 && size != 4 && size != 8 {
@@ -87,7 +84,7 @@ func (s *Session) SetWatchpoint(slot int, addr uint64, typ WatchpointType, size
return fmt.Errorf("debug: set watchpoint control: %w", err) return fmt.Errorf("debug: set watchpoint control: %w", err)
} }
wpSlots[slot] = true s.wpSlots[slot] = true
return nil return nil
} }
@@ -95,7 +92,7 @@ func (s *Session) ClearWatchpoint(slot int) error {
if slot < 0 || slot >= maxWatchpoints { if slot < 0 || slot >= maxWatchpoints {
return fmt.Errorf("debug: watchpoint slot must be 0-%d", maxWatchpoints-1) return fmt.Errorf("debug: watchpoint slot must be 0-%d", maxWatchpoints-1)
} }
if !wpSlots[slot] { if !s.wpSlots[slot] {
return fmt.Errorf("debug: watchpoint slot %d is not in use", slot) return fmt.Errorf("debug: watchpoint slot %d is not in use", slot)
} }
@@ -103,13 +100,13 @@ func (s *Session) ClearWatchpoint(slot int) error {
if err := ptracePokeUser(s.pid, uintptr(0x1001+slot*8), 0); err != nil { if err := ptracePokeUser(s.pid, uintptr(0x1001+slot*8), 0); err != nil {
return err return err
} }
wpSlots[slot] = false s.wpSlots[slot] = false
return nil return nil
} }
func (s *Session) ClearAllWatchpoints() error { func (s *Session) ClearAllWatchpoints() error {
for slot := 0; slot < maxWatchpoints; slot++ { for slot := 0; slot < maxWatchpoints; slot++ {
if wpSlots[slot] { if s.wpSlots[slot] {
if err := s.ClearWatchpoint(slot); err != nil { if err := s.ClearWatchpoint(slot); err != nil {
return err return err
} }