proc/native: support watchpoints on Windows (#2651)

Documentation/backend_test_health.md

@@ -25,7 +25,6 @@ Tests skipped by each supported backend:
 	* 2 upstream issue - https://github.com/golang/go/issues/29322
 * rr skipped = 3
 	* 3 not implemented
-* windows skipped = 5
+* windows skipped = 2
 	* 1 broken
-	* 3 not implemented
 	* 1 upstream issue

pkg/proc/native/hwbreak_amd64.go

+package native
+
+import (
+	"github.com/go-delve/delve/pkg/proc"
+	"github.com/go-delve/delve/pkg/proc/amd64util"
+)
+
+func (t *nativeThread) writeHardwareBreakpoint(addr uint64, wtype proc.WatchType, idx uint8) error {
+	return t.withDebugRegisters(func(drs *amd64util.DebugRegisters) error {
+		return drs.SetBreakpoint(idx, addr, wtype.Read(), wtype.Write(), wtype.Size())
+	})
+}
+
+func (t *nativeThread) clearHardwareBreakpoint(addr uint64, wtype proc.WatchType, idx uint8) error {
+	return t.withDebugRegisters(func(drs *amd64util.DebugRegisters) error {
+		drs.ClearBreakpoint(idx)
+		return nil
+	})
+}
+
+func (t *nativeThread) findHardwareBreakpoint() (*proc.Breakpoint, error) {
+	var retbp *proc.Breakpoint
+	err := t.withDebugRegisters(func(drs *amd64util.DebugRegisters) error {
+		ok, idx := drs.GetActiveBreakpoint()
+		if ok {
+			for _, bp := range t.dbp.Breakpoints().M {
+				if bp.WatchType != 0 && bp.HWBreakIndex == idx {
+					retbp = bp
+					break
+				}
+			}
+		}
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+	return retbp, nil
+}

pkg/proc/native/hwbreak_other.go

+// +build !amd64
+
+package native
+
+import (
+	"errors"
+
+	"github.com/go-delve/delve/pkg/proc"
+)
+
+func (t *nativeThread) findHardwareBreakpoint() (*proc.Breakpoint, error) {
+	return nil, errors.New("hardware breakpoints not supported")
+}
+
+func (t *nativeThread) writeHardwareBreakpoint(addr uint64, wtype proc.WatchType, idx uint8) error {
+	return errors.New("hardware breakpoints not supported")
+}
+
+func (t *nativeThread) clearHardwareBreakpoint(addr uint64, wtype proc.WatchType, idx uint8) error {
+	return errors.New("hardware breakpoints not supported")
+}

pkg/proc/native/nonative_darwin.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/go-delve/delve/pkg/dwarf/op"
 	"github.com/go-delve/delve/pkg/proc"
+	"github.com/go-delve/delve/pkg/proc/amd64util"
 	"github.com/go-delve/delve/pkg/proc/internal/ebpf"
 )
 
@@ -130,16 +131,8 @@ func (t *nativeThread) restoreRegisters(sr proc.Registers) error {
 	panic(ErrNativeBackendDisabled)
 }
 
-func (t *nativeThread) findHardwareBreakpoint() (*proc.Breakpoint, error) {
-	panic(ErrNativeBackendDisabled)
-}
-
-func (t *nativeThread) writeHardwareBreakpoint(addr uint64, wtype proc.WatchType, idx uint8) error {
-	panic(ErrNativeBackendDisabled)
-}
-
-func (t *nativeThread) clearHardwareBreakpoint(addr uint64, wtype proc.WatchType, idx uint8) error {
-	panic(ErrNativeBackendDisabled)
+func (t *nativeThread) withDebugRegisters(f func(*amd64util.DebugRegisters) error) error {
+	return proc.ErrHWBreakUnsupported
 }
 
 // Stopped returns whether the thread is stopped at

pkg/proc/native/threads_darwin.go

@@ -13,6 +13,7 @@ import (
 	sys "golang.org/x/sys/unix"
 
 	"github.com/go-delve/delve/pkg/proc"
+	"github.com/go-delve/delve/pkg/proc/amd64util"
 )
 
 // waitStatus is a synonym for the platform-specific WaitStatus
@@ -133,14 +134,6 @@ func (t *nativeThread) restoreRegisters(sr proc.Registers) error {
 	return errors.New("not implemented")
 }
 
-func (t *nativeThread) writeHardwareBreakpoint(addr uint64, wtype proc.WatchType, idx uint8) error {
+func (t *nativeThread) withDebugRegisters(f func(*amd64util.DebugRegisters) error) error {
 	return proc.ErrHWBreakUnsupported
 }
-
-func (t *nativeThread) clearHardwareBreakpoint(addr uint64, wtype proc.WatchType, idx uint8) error {
-	return proc.ErrHWBreakUnsupported
-}
-
-func (t *nativeThread) findHardwareBreakpoint() (*proc.Breakpoint, error) {
-	return nil, nil
-}

pkg/proc/native/threads_freebsd.go

@@ -11,6 +11,7 @@ import (
 	sys "golang.org/x/sys/unix"
 
 	"github.com/go-delve/delve/pkg/proc"
+	"github.com/go-delve/delve/pkg/proc/amd64util"
 )
 
 type waitStatus sys.WaitStatus
@@ -121,14 +122,6 @@ func (t *nativeThread) ReadMemory(data []byte, addr uint64) (n int, err error) {
 	return n, err
 }
 
-func (t *nativeThread) writeHardwareBreakpoint(addr uint64, wtype proc.WatchType, idx uint8) error {
+func (t *nativeThread) withDebugRegisters(f func(*amd64util.DebugRegisters) error) error {
 	return proc.ErrHWBreakUnsupported
 }
-
-func (t *nativeThread) clearHardwareBreakpoint(addr uint64, wtype proc.WatchType, idx uint8) error {
-	return proc.ErrHWBreakUnsupported
-}
-
-func (t *nativeThread) findHardwareBreakpoint() (*proc.Breakpoint, error) {
-	return nil, nil
-}

pkg/proc/native/threads_linux_386.go

@@ -8,15 +8,3 @@ import (
 func (t *nativeThread) restoreRegisters(savedRegs proc.Registers) error {
 	return fmt.Errorf("restore regs not supported on i386")
 }
-
-func (t *nativeThread) writeHardwareBreakpoint(addr uint64, wtype proc.WatchType, idx uint8) error {
-	return proc.ErrHWBreakUnsupported
-}
-
-func (t *nativeThread) clearHardwareBreakpoint(addr uint64, wtype proc.WatchType, idx uint8) error {
-	return proc.ErrHWBreakUnsupported
-}
-
-func (t *nativeThread) findHardwareBreakpoint() (*proc.Breakpoint, error) {
-	return nil, nil
-}

pkg/proc/native/threads_linux_amd64.go

@@ -86,36 +86,3 @@ func (t *nativeThread) withDebugRegisters(f func(*amd64util.DebugRegisters) erro
 	}
 	return err
 }
-
-func (t *nativeThread) writeHardwareBreakpoint(addr uint64, wtype proc.WatchType, idx uint8) error {
-	return t.withDebugRegisters(func(drs *amd64util.DebugRegisters) error {
-		return drs.SetBreakpoint(idx, addr, wtype.Read(), wtype.Write(), wtype.Size())
-	})
-}
-
-func (t *nativeThread) clearHardwareBreakpoint(addr uint64, wtype proc.WatchType, idx uint8) error {
-	return t.withDebugRegisters(func(drs *amd64util.DebugRegisters) error {
-		drs.ClearBreakpoint(idx)
-		return nil
-	})
-}
-
-func (t *nativeThread) findHardwareBreakpoint() (*proc.Breakpoint, error) {
-	var retbp *proc.Breakpoint
-	err := t.withDebugRegisters(func(drs *amd64util.DebugRegisters) error {
-		ok, idx := drs.GetActiveBreakpoint()
-		if ok {
-			for _, bp := range t.dbp.Breakpoints().M {
-				if bp.WatchType != 0 && bp.HWBreakIndex == idx {
-					retbp = bp
-					break
-				}
-			}
-		}
-		return nil
-	})
-	if err != nil {
-		return nil, err
-	}
-	return retbp, nil
-}

pkg/proc/native/threads_linux_arm64.go

@@ -42,15 +42,3 @@ func (t *nativeThread) restoreRegisters(savedRegs proc.Registers) error {
 	}
 	return restoreRegistersErr
 }
-
-func (t *nativeThread) writeHardwareBreakpoint(addr uint64, wtype proc.WatchType, idx uint8) error {
-	return proc.ErrHWBreakUnsupported
-}
-
-func (t *nativeThread) clearHardwareBreakpoint(addr uint64, wtype proc.WatchType, idx uint8) error {
-	return proc.ErrHWBreakUnsupported
-}
-
-func (t *nativeThread) findHardwareBreakpoint() (*proc.Breakpoint, error) {
-	return nil, nil
-}

pkg/proc/native/threads_windows.go

@@ -7,6 +7,7 @@ import (
 	sys "golang.org/x/sys/windows"
 
 	"github.com/go-delve/delve/pkg/proc"
+	"github.com/go-delve/delve/pkg/proc/amd64util"
 	"github.com/go-delve/delve/pkg/proc/winutil"
 )
 
@@ -157,14 +158,25 @@ func (t *nativeThread) restoreRegisters(savedRegs proc.Registers) error {
 	return _SetThreadContext(t.os.hThread, savedRegs.(*winutil.AMD64Registers).Context)
 }
 
-func (t *nativeThread) writeHardwareBreakpoint(addr uint64, wtype proc.WatchType, idx uint8) error {
-	return proc.ErrHWBreakUnsupported
-}
+func (t *nativeThread) withDebugRegisters(f func(*amd64util.DebugRegisters) error) error {
+	context := winutil.NewCONTEXT()
+	context.ContextFlags = _CONTEXT_DEBUG_REGISTERS
 
-func (t *nativeThread) clearHardwareBreakpoint(addr uint64, wtype proc.WatchType, idx uint8) error {
-	return proc.ErrHWBreakUnsupported
-}
+	err := _GetThreadContext(t.os.hThread, context)
+	if err != nil {
+		return err
+	}
+
+	drs := amd64util.NewDebugRegisters(&context.Dr0, &context.Dr1, &context.Dr2, &context.Dr3, &context.Dr6, &context.Dr7)
+
+	err = f(drs)
+	if err != nil {
+		return err
+	}
+
+	if drs.Dirty {
+		return _SetThreadContext(t.os.hThread, context)
+	}
 
-func (t *nativeThread) findHardwareBreakpoint() (*proc.Breakpoint, error) {
-	return nil, nil
+	return nil
 }

pkg/proc/proc_test.go

@@ -5332,7 +5332,6 @@ func TestVariablesWithExternalLinking(t *testing.T) {
 }
 
 func TestWatchpointsBasic(t *testing.T) {
-	skipOn(t, "not implemented", "windows")
 	skipOn(t, "not implemented", "freebsd")
 	skipOn(t, "not implemented", "darwin")
 	skipOn(t, "not implemented", "386")
@@ -5378,7 +5377,6 @@ func TestWatchpointsBasic(t *testing.T) {
 }
 
 func TestWatchpointCounts(t *testing.T) {
-	skipOn(t, "not implemented", "windows")
 	skipOn(t, "not implemented", "freebsd")
 	skipOn(t, "not implemented", "darwin")
 	skipOn(t, "not implemented", "386")
@@ -5496,7 +5494,6 @@ func TestDwrapStartLocation(t *testing.T) {
 }
 
 func TestWatchpointStack(t *testing.T) {
-	skipOn(t, "not implemented", "windows")
 	skipOn(t, "not implemented", "freebsd")
 	skipOn(t, "not implemented", "darwin")
 	skipOn(t, "not implemented", "386")