Fix compilation warnings in JS and Windows builds

Warnings raised by Emscripten 1.38.0 and MinGW64 5.0.4 / GCC 8.3.0.

JS can now build with `werror=yes warnings=extra`.
MinGW64 still has a few warnings to resolve with `warnings=extra`,
and only one with `warnings=all`.

Part of #29033 and #29801.

11 files changed, 44 insertions, 39 deletions

diff --git a/drivers/unix/net_socket_posix.cpp b/drivers/unix/net_socket_posix.cpp
index 37abccbe27..75d51c8503 100644
--- a/drivers/unix/net_socket_posix.cpp
+++ b/drivers/unix/net_socket_posix.cpp
@@ -306,7 +306,7 @@ Error NetSocketPosix::bind(IP_Address p_addr, uint16_t p_port) {
 	sockaddr_storage addr;
 	size_t addr_size = _set_addr_storage(&addr, p_addr, p_port, _ip_type);
 
-	if (::bind(_sock, (struct sockaddr *)&addr, addr_size) == SOCK_EMPTY) {
+	if (::bind(_sock, (struct sockaddr *)&addr, addr_size) != 0) {
 		close();
 		ERR_FAIL_V(ERR_UNAVAILABLE);
 	}
@@ -317,7 +317,7 @@ Error NetSocketPosix::bind(IP_Address p_addr, uint16_t p_port) {
 Error NetSocketPosix::listen(int p_max_pending) {
 	ERR_FAIL_COND_V(!is_open(), ERR_UNCONFIGURED);
 
-	if (::listen(_sock, p_max_pending) == SOCK_EMPTY) {
+	if (::listen(_sock, p_max_pending) != 0) {
 
 		close();
 		ERR_FAIL_V(FAILED);
@@ -334,7 +334,7 @@ Error NetSocketPosix::connect_to_host(IP_Address p_host, uint16_t p_port) {
 	struct sockaddr_storage addr;
 	size_t addr_size = _set_addr_storage(&addr, p_host, p_port, _ip_type);
 
-	if (::connect(_sock, (struct sockaddr *)&addr, addr_size) == SOCK_EMPTY) {
+	if (::connect(_sock, (struct sockaddr *)&addr, addr_size) != 0) {
 
 		NetError err = _get_socket_error();
 
diff --git a/drivers/wasapi/audio_driver_wasapi.cpp b/drivers/wasapi/audio_driver_wasapi.cpp
index c97849ef07..fea38ee95d 100644
--- a/drivers/wasapi/audio_driver_wasapi.cpp
+++ b/drivers/wasapi/audio_driver_wasapi.cpp
@@ -167,13 +167,13 @@ Error AudioDriverWASAPI::audio_device_init(AudioDeviceWASAPI *p_device, bool p_c
 		ERR_FAIL_COND_V(hr != S_OK, ERR_CANT_OPEN);
 
 		for (ULONG i = 0; i < count && !found; i++) {
-			IMMDevice *device = NULL;
+			IMMDevice *tmp_device = NULL;
 
-			hr = devices->Item(i, &device);
+			hr = devices->Item(i, &tmp_device);
 			ERR_BREAK(hr != S_OK);
 
 			IPropertyStore *props = NULL;
-			hr = device->OpenPropertyStore(STGM_READ, &props);
+			hr = tmp_device->OpenPropertyStore(STGM_READ, &props);
 			ERR_BREAK(hr != S_OK);
 
 			PROPVARIANT propvar;
@@ -183,7 +183,7 @@ Error AudioDriverWASAPI::audio_device_init(AudioDeviceWASAPI *p_device, bool p_c
 			ERR_BREAK(hr != S_OK);
 
 			if (p_device->device_name == String(propvar.pwszVal)) {
-				hr = device->GetId(&strId);
+				hr = tmp_device->GetId(&strId);
 				ERR_BREAK(hr != S_OK);
 
 				found = true;
@@ -191,7 +191,7 @@ Error AudioDriverWASAPI::audio_device_init(AudioDeviceWASAPI *p_device, bool p_c
 
 			PropVariantClear(&propvar);
 			props->Release();
-			device->Release();
+			tmp_device->Release();
 		}
 
 		if (found) {
@@ -289,7 +289,7 @@ Error AudioDriverWASAPI::audio_device_init(AudioDeviceWASAPI *p_device, bool p_c
 	}
 
 	DWORD streamflags = 0;
-	if (mix_rate != pwfex->nSamplesPerSec) {
+	if ((DWORD)mix_rate != pwfex->nSamplesPerSec) {
 		streamflags |= AUDCLNT_STREAMFLAGS_RATEADJUST;
 		pwfex->nSamplesPerSec = mix_rate;
 		pwfex->nAvgBytesPerSec = pwfex->nSamplesPerSec * pwfex->nChannels * (pwfex->wBitsPerSample / 8);
@@ -571,7 +571,7 @@ void AudioDriverWASAPI::thread_func(void *p_udata) {
 			if (ad->audio_output.active) {
 				ad->audio_server_process(ad->buffer_frames, ad->samples_in.ptrw());
 			} else {
-				for (unsigned int i = 0; i < ad->samples_in.size(); i++) {
+				for (int i = 0; i < ad->samples_in.size(); i++) {
 					ad->samples_in.write[i] = 0;
 				}
 			}
@@ -699,7 +699,7 @@ void AudioDriverWASAPI::thread_func(void *p_udata) {
 					ERR_BREAK(hr != S_OK);
 
 					// fixme: Only works for floating point atm
-					for (int j = 0; j < num_frames_available; j++) {
+					for (UINT32 j = 0; j < num_frames_available; j++) {
 						int32_t l, r;
 
 						if (flags & AUDCLNT_BUFFERFLAGS_SILENT) {
diff --git a/drivers/windows/file_access_windows.cpp b/drivers/windows/file_access_windows.cpp
index 31360d319f..646e744248 100644
--- a/drivers/windows/file_access_windows.cpp
+++ b/drivers/windows/file_access_windows.cpp
@@ -93,7 +93,7 @@ Error FileAccessWindows::_open(const String &p_path, int p_mode_flags) {
 	// a file using the wrong case (which *works* on Windows, but won't on other
 	// platforms).
 	if (p_mode_flags == READ) {
-		WIN32_FIND_DATAW d = { 0 };
+		WIN32_FIND_DATAW d;
 		HANDLE f = FindFirstFileW(path.c_str(), &d);
 		if (f) {
 			String fname = d.cFileName;
@@ -302,7 +302,7 @@ void FileAccessWindows::store_buffer(const uint8_t *p_src, int p_length) {
 		}
 		prev_op = WRITE;
 	}
-	ERR_FAIL_COND(fwrite(p_src, 1, p_length, f) != p_length);
+	ERR_FAIL_COND(fwrite(p_src, 1, p_length, f) != (size_t)p_length);
 }
 
 bool FileAccessWindows::file_exists(const String &p_name) {
diff --git a/modules/webrtc/webrtc_data_channel_js.cpp b/modules/webrtc/webrtc_data_channel_js.cpp
index ce2fada634..069918cc9c 100644
--- a/modules/webrtc/webrtc_data_channel_js.cpp
+++ b/modules/webrtc/webrtc_data_channel_js.cpp
@@ -68,7 +68,7 @@ void WebRTCDataChannelJS::_on_error() {
 }
 
 void WebRTCDataChannelJS::_on_message(uint8_t *p_data, uint32_t p_size, bool p_is_string) {
-	if (in_buffer.space_left() < p_size + 5) {
+	if (in_buffer.space_left() < (int)(p_size + 5)) {
 		ERR_EXPLAIN("Buffer full! Dropping data");
 		ERR_FAIL();
 	}
diff --git a/platform/javascript/audio_driver_javascript.cpp b/platform/javascript/audio_driver_javascript.cpp
index 11104007e2..163826f828 100644
--- a/platform/javascript/audio_driver_javascript.cpp
+++ b/platform/javascript/audio_driver_javascript.cpp
@@ -99,7 +99,7 @@ Error AudioDriverJavaScript::init() {
 		return FAILED;
 	}
 
-	if (!internal_buffer || memarr_len(internal_buffer) != buffer_length * channel_count) {
+	if (!internal_buffer || (int)memarr_len(internal_buffer) != buffer_length * channel_count) {
 		if (internal_buffer)
 			memdelete_arr(internal_buffer);
 		internal_buffer = memnew_arr(float, buffer_length *channel_count);
diff --git a/platform/windows/joypad_windows.cpp b/platform/windows/joypad_windows.cpp
index 5a399cdf90..432060f4fe 100644
--- a/platform/windows/joypad_windows.cpp
+++ b/platform/windows/joypad_windows.cpp
@@ -103,17 +103,17 @@ bool JoypadWindows::is_xinput_device(const GUID *p_guid) {
 	PRAWINPUTDEVICELIST dev_list = NULL;
 	unsigned int dev_list_count = 0;
 
-	if (GetRawInputDeviceList(NULL, &dev_list_count, sizeof(RAWINPUTDEVICELIST)) == -1) {
+	if (GetRawInputDeviceList(NULL, &dev_list_count, sizeof(RAWINPUTDEVICELIST)) == (UINT)-1) {
 		return false;
 	}
 	dev_list = (PRAWINPUTDEVICELIST)malloc(sizeof(RAWINPUTDEVICELIST) * dev_list_count);
 	if (!dev_list) return false;
 
-	if (GetRawInputDeviceList(dev_list, &dev_list_count, sizeof(RAWINPUTDEVICELIST)) == -1) {
+	if (GetRawInputDeviceList(dev_list, &dev_list_count, sizeof(RAWINPUTDEVICELIST)) == (UINT)-1) {
 		free(dev_list);
 		return false;
 	}
-	for (int i = 0; i < dev_list_count; i++) {
+	for (unsigned int i = 0; i < dev_list_count; i++) {
 
 		RID_DEVICE_INFO rdi;
 		char dev_name[128];
@@ -334,9 +334,9 @@ void JoypadWindows::process_joypads() {
 		if (joy.state.dwPacketNumber != joy.last_packet) {
 
 			int button_mask = XINPUT_GAMEPAD_DPAD_UP;
-			for (int i = 0; i <= 16; i++) {
+			for (int j = 0; j <= 16; i++) {
 
-				input->joy_button(joy.id, i, joy.state.Gamepad.wButtons & button_mask);
+				input->joy_button(joy.id, j, joy.state.Gamepad.wButtons & button_mask);
 				button_mask = button_mask * 2;
 			}
 
@@ -406,7 +406,7 @@ void JoypadWindows::process_joypads() {
 
 		// on mingw, these constants are not constants
 		int count = 6;
-		int axes[] = { DIJOFS_X, DIJOFS_Y, DIJOFS_Z, DIJOFS_RX, DIJOFS_RY, DIJOFS_RZ };
+		unsigned int axes[] = { DIJOFS_X, DIJOFS_Y, DIJOFS_Z, DIJOFS_RX, DIJOFS_RY, DIJOFS_RZ };
 		int values[] = { js.lX, js.lY, js.lZ, js.lRx, js.lRy, js.lRz };
 
 		for (int j = 0; j < joy->joy_axis.size(); j++) {
@@ -426,7 +426,11 @@ void JoypadWindows::post_hat(int p_device, DWORD p_dpad) {
 
 	int dpad_val = 0;
 
-	if (p_dpad == -1) {
+	// Should be -1 when centered, but according to docs:
+	// "Some drivers report the centered position of the POV indicator as 65,535. Determine whether the indicator is centered as follows:
+	//  BOOL POVCentered = (LOWORD(dwPOV) == 0xFFFF);"
+	// https://docs.microsoft.com/en-us/previous-versions/windows/desktop/ee416628(v%3Dvs.85)#remarks
+	if (LOWORD(p_dpad) == 0xFFFF) {
 		dpad_val = InputDefault::HAT_MASK_CENTER;
 	}
 	if (p_dpad == 0) {
diff --git a/platform/windows/os_windows.cpp b/platform/windows/os_windows.cpp
index 4cd637a4b2..af4f5d22bf 100644
--- a/platform/windows/os_windows.cpp
+++ b/platform/windows/os_windows.cpp
@@ -94,6 +94,7 @@ static BOOL CALLBACK _MonitorEnumProcSize(HMONITOR hMonitor, HDC hdcMonitor, LPR
 	return TRUE;
 }
 
+#ifdef DEBUG_ENABLED
 static String format_error_message(DWORD id) {
 
 	LPWSTR messageBuffer = NULL;
@@ -106,6 +107,7 @@ static String format_error_message(DWORD id) {
 
 	return msg;
 }
+#endif // DEBUG_ENABLED
 
 extern HINSTANCE godot_hinstance;
 
@@ -555,6 +557,7 @@ LRESULT OS_Windows::WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
 					break;
 				}
 			}
+			FALLTHROUGH;
 		case WM_MBUTTONDOWN:
 		case WM_MBUTTONUP:
 		case WM_RBUTTONDOWN:
@@ -583,7 +586,6 @@ LRESULT OS_Windows::WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
 				case WM_MBUTTONDOWN: {
 					mb->set_pressed(true);
 					mb->set_button_index(3);
-
 				} break;
 				case WM_MBUTTONUP: {
 					mb->set_pressed(false);
@@ -598,19 +600,16 @@ LRESULT OS_Windows::WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
 					mb->set_button_index(2);
 				} break;
 				case WM_LBUTTONDBLCLK: {
-
 					mb->set_pressed(true);
 					mb->set_button_index(1);
 					mb->set_doubleclick(true);
 				} break;
 				case WM_RBUTTONDBLCLK: {
-
 					mb->set_pressed(true);
 					mb->set_button_index(2);
 					mb->set_doubleclick(true);
 				} break;
 				case WM_MBUTTONDBLCLK: {
-
 					mb->set_pressed(true);
 					mb->set_button_index(3);
 					mb->set_doubleclick(true);
@@ -1816,11 +1815,11 @@ void OS_Windows::set_window_size(const Size2 p_size) {
 
 	// Don't let the mouse leave the window when resizing to a smaller resolution
 	if (mouse_mode == MOUSE_MODE_CONFINED) {
-		RECT rect;
-		GetClientRect(hWnd, &rect);
-		ClientToScreen(hWnd, (POINT *)&rect.left);
-		ClientToScreen(hWnd, (POINT *)&rect.right);
-		ClipCursor(&rect);
+		RECT crect;
+		GetClientRect(hWnd, &crect);
+		ClientToScreen(hWnd, (POINT *)&crect.left);
+		ClientToScreen(hWnd, (POINT *)&crect.right);
+		ClipCursor(&crect);
 	}
 }
 void OS_Windows::set_window_fullscreen(bool p_enabled) {
@@ -2193,6 +2192,8 @@ uint64_t OS_Windows::get_unix_time() const {
 	FILETIME fep;
 	SystemTimeToFileTime(&ep, &fep);
 
+	// FIXME: dereferencing type-punned pointer will break strict-aliasing rules (GCC warning)
+	// https://docs.microsoft.com/en-us/windows/desktop/api/minwinbase/ns-minwinbase-filetime#remarks
 	return (*(uint64_t *)&ft - *(uint64_t *)&fep) / 10000000;
 };
 
@@ -2378,7 +2379,7 @@ void OS_Windows::set_custom_mouse_cursor(const RES &p_cursor, CursorShape p_shap
 		}
 
 		// Finally, create the icon
-		ICONINFO iconinfo = { 0 };
+		ICONINFO iconinfo;
 		iconinfo.fIcon = FALSE;
 		iconinfo.xHotspot = p_hotspot.x;
 		iconinfo.yHotspot = p_hotspot.y;
@@ -2531,9 +2532,9 @@ Error OS_Windows::execute(const String &p_path, const List<String> &p_arguments,
 
 	if (p_blocking) {
 
-		DWORD ret = WaitForSingleObject(pi.pi.hProcess, INFINITE);
+		DWORD ret2 = WaitForSingleObject(pi.pi.hProcess, INFINITE);
 		if (r_exitcode)
-			*r_exitcode = ret;
+			*r_exitcode = ret2;
 
 		CloseHandle(pi.pi.hProcess);
 		CloseHandle(pi.pi.hThread);
diff --git a/platform/windows/power_windows.cpp b/platform/windows/power_windows.cpp
index b96ae51132..0efd88c216 100644
--- a/platform/windows/power_windows.cpp
+++ b/platform/windows/power_windows.cpp
@@ -89,7 +89,7 @@ bool PowerWindows::GetPowerInfo_Windows() {
 		if (pct != 255) { /* 255 == unknown */
 			percent_left = (pct > 100) ? 100 : pct; /* clamp between 0%, 100% */
 		}
-		if (secs != 0xFFFFFFFF) { /* ((DWORD)-1) == unknown */
+		if (secs != (int)0xFFFFFFFF) { /* ((DWORD)-1) == unknown */
 			nsecs_left = secs;
 		}
 	}
diff --git a/platform/windows/windows_terminal_logger.cpp b/platform/windows/windows_terminal_logger.cpp
index 7def419103..adbdafb07e 100644
--- a/platform/windows/windows_terminal_logger.cpp
+++ b/platform/windows/windows_terminal_logger.cpp
@@ -45,7 +45,7 @@ void WindowsTerminalLogger::logv(const char *p_format, va_list p_list, bool p_er
 	int len = vsnprintf(buf, BUFFER_SIZE, p_format, p_list);
 	if (len <= 0)
 		return;
-	if (len >= BUFFER_SIZE)
+	if ((unsigned int)len >= BUFFER_SIZE)
 		len = BUFFER_SIZE; // Output is too big, will be truncated
 	buf[len] = 0;
 
@@ -154,4 +154,4 @@ void WindowsTerminalLogger::log_error(const char *p_function, const char *p_file
 
 WindowsTerminalLogger::~WindowsTerminalLogger() {}
 
-#endif
\ No newline at end of file
+#endif
diff --git a/scene/2d/position_2d.cpp b/scene/2d/position_2d.cpp
index 8bccf117fd..f0c46a5fb7 100644
--- a/scene/2d/position_2d.cpp
+++ b/scene/2d/position_2d.cpp
@@ -33,6 +33,8 @@
 #include "core/engine.h"
 #include "scene/resources/texture.h"
 
+const float DEFAULT_GIZMO_EXTENTS = 10.0;
+
 void Position2D::_draw_cross() {
 
 	float extents = get_gizmo_extents();
diff --git a/scene/2d/position_2d.h b/scene/2d/position_2d.h
index dc9cc2df15..ec73c02d2b 100644
--- a/scene/2d/position_2d.h
+++ b/scene/2d/position_2d.h
@@ -37,8 +37,6 @@ class Position2D : public Node2D {
 
 	GDCLASS(Position2D, Node2D)
 
-	const float DEFAULT_GIZMO_EXTENTS = 10.0;
-
 	void _draw_cross();
 
 protected: