purego: fix bool field placement at non-zero offsets (#351)

Bool fields were incorrectly placed at bit 0 regardless of their offset
within the struct. This caused incorrect marshalling when bool fields
appeared after other fields.

The fix properly shifts the bool value by the current bit offset,
ensuring it's placed at the correct position in the packed struct data.

Adds regression test with FloatAndBool struct to verify the fix.

Closes #350

commit: f0510f17e9ec8629aac1751cea7f51ee0d1e557f
author: Travis Cline · 12mo ago · 2025-10-27 03:33 UTC
committer: Hajime Hoshi · 12mo ago · 2025-10-27 03:35 UTC
parent: 291e8af
signature: unsigned

5 files · +26 -3

M struct_amd64.go +1 -1


@@ -165,7 +165,7 @@ func tryPlaceRegister(v reflect.Value, addFloat func(uintptr), addInt func(uintp
165	165		place(f)
166	166		case reflect.Bool:
167	167		if f.Bool() {
168		-	val \|= 1
	168	+	val \|= 1 << shift
169	169		}
170	170		shift += 8
171	171		class \|= _INTEGER


@@ -165,7 +165,7 @@ func tryPlaceRegister(v reflect.Value, addFloat func(uintptr), addInt func(uintp
165		place(f)	165		place(f)
166		case reflect.Bool:	166		case reflect.Bool:
167		if f.Bool() {	167		if f.Bool() {
168	-	val \|= 1	168	+	val \|= 1 << shift
169		}	169		}
170		shift += 8	170		shift += 8
171		class \|= _INTEGER	171		class \|= _INTEGER

M struct_arm64.go +1 -1


@@ -123,7 +123,7 @@ func placeRegisters(v reflect.Value, addFloat func(uintptr), addInt func(uintptr
123	123		place(f)
124	124		case reflect.Bool:
125	125		if f.Bool() {
126		-	val \|= 1
	126	+	val \|= 1 << shift
127	127		}
128	128		shift += 8
129	129		class \|= _INT


@@ -123,7 +123,7 @@ func placeRegisters(v reflect.Value, addFloat func(uintptr), addInt func(uintptr
123		place(f)	123		place(f)
124		case reflect.Bool:	124		case reflect.Bool:
125		if f.Bool() {	125		if f.Bool() {
126	-	val \|= 1	126	+	val \|= 1 << shift
127		}	127		}
128		shift += 8	128		shift += 8
129		class \|= _INT	129		class \|= _INT

M struct_loong64.go +1 -1


@@ -104,7 +104,7 @@ func placeRegisters(v reflect.Value, addFloat func(uintptr), addInt func(uintptr
104	104		place(f)
105	105		case reflect.Bool:
106	106		if f.Bool() {
107		-	val \|= 1
	107	+	val \|= 1 << shift
108	108		}
109	109		shift += 8
110	110		class \|= _INT


@@ -104,7 +104,7 @@ func placeRegisters(v reflect.Value, addFloat func(uintptr), addInt func(uintptr
104		place(f)	104		place(f)
105		case reflect.Bool:	105		case reflect.Bool:
106		if f.Bool() {	106		if f.Bool() {
107	-	val \|= 1	107	+	val \|= 1 << shift
108		}	108		}
109		shift += 8	109		shift += 8
110		class \|= _INT	110		class \|= _INT

M struct_test.go +14 -0


@@ -472,6 +472,20 @@ func TestRegisterFunc_structArgs(t *testing.T) {
472	472		t.Fatalf("TakeGoUintAndReturn returned %+v wanted %+v", ret, expected)
473	473		}
474	474		}
	475	+	{
	476	+	type FloatAndBool struct {
	477	+	x float32
	478	+	y bool
	479	+	}
	480	+	var FloatAndBoolFn func(FloatAndBool) int32
	481	+	purego.RegisterLibFunc(&FloatAndBoolFn, lib, "FloatAndBool")
	482	+	if ret := FloatAndBoolFn(FloatAndBool{x: 12345.0, y: true}); ret != 1 {
	483	+	t.Fatalf("FloatAndBool(y: true) = %d, want 1", ret)
	484	+	}
	485	+	if ret := FloatAndBoolFn(FloatAndBool{x: 12345.0, y: false}); ret != 0 {
	486	+	t.Fatalf("FloatAndBool(y: false) = %d, want 0", ret)
	487	+	}
	488	+	}
475	489		}
476	490
477	491		func TestRegisterFunc_structReturns(t *testing.T) {


@@ -472,6 +472,20 @@ func TestRegisterFunc_structArgs(t *testing.T) {
472	t.Fatalf("TakeGoUintAndReturn returned %+v wanted %+v", ret, expected)	472		t.Fatalf("TakeGoUintAndReturn returned %+v wanted %+v", ret, expected)
473	}	473		}
474	}	474		}
		475	+	{
		476	+	type FloatAndBool struct {
		477	+	x float32
		478	+	y bool
		479	+	}
		480	+	var FloatAndBoolFn func(FloatAndBool) int32
		481	+	purego.RegisterLibFunc(&FloatAndBoolFn, lib, "FloatAndBool")
		482	+	if ret := FloatAndBoolFn(FloatAndBool{x: 12345.0, y: true}); ret != 1 {
		483	+	t.Fatalf("FloatAndBool(y: true) = %d, want 1", ret)
		484	+	}
		485	+	if ret := FloatAndBoolFn(FloatAndBool{x: 12345.0, y: false}); ret != 0 {
		486	+	t.Fatalf("FloatAndBool(y: false) = %d, want 0", ret)
		487	+	}
		488	+	}
475	}	489		}
476		490
477	func TestRegisterFunc_structReturns(t *testing.T) {	491		func TestRegisterFunc_structReturns(t *testing.T) {

M testdata/structtest/struct_test.c +9 -0


@@ -352,3 +352,12 @@ GoUint GoUint4(struct GoUint4 g) {
352	352		GoUint TakeGoUintAndReturn(GoUint a) {
353	353		return a;
354	354		}
	355	+
	356	+	struct FloatAndBool {
	357	+	float value;
	358	+	_Bool has_value;
	359	+	};
	360	+
	361	+	int FloatAndBool(struct FloatAndBool f) {
	362	+	return f.has_value;
	363	+	}


@@ -352,3 +352,12 @@ GoUint GoUint4(struct GoUint4 g) {
352	GoUint TakeGoUintAndReturn(GoUint a) {	352		GoUint TakeGoUintAndReturn(GoUint a) {
353	return a;	353		return a;
354	}	354		}
		355	+
		356	+	struct FloatAndBool {
		357	+	float value;
		358	+	_Bool has_value;
		359	+	};
		360	+
		361	+	int FloatAndBool(struct FloatAndBool f) {
		362	+	return f.has_value;
		363	+	}