typedefs: Cleanup unused macros and unnecessary checks

We now require a compiler with C++17 support, so we don't need to
check for features added to GCC 5 or Clang 3.2.

Clang builtin availability checks were unused anyway as Clang defines
`__GNUC__` as it's also a GNU C implementation.

Fixes #36986.

6 files changed, 79 insertions, 153 deletions

diff --git a/core/cowdata.h b/core/cowdata.h
index 4fdcaf3cea..fba3f64899 100644
--- a/core/cowdata.h
+++ b/core/cowdata.h
@@ -82,24 +82,25 @@ private:
 	}
 
 	_FORCE_INLINE_ size_t _get_alloc_size(size_t p_elements) const {
-		//return nearest_power_of_2_templated(p_elements*sizeof(T)+sizeof(SafeRefCount)+sizeof(int));
 		return next_power_of_2(p_elements * sizeof(T));
 	}
 
 	_FORCE_INLINE_ bool _get_alloc_size_checked(size_t p_elements, size_t *out) const {
-#if defined(_add_overflow) && defined(_mul_overflow)
+#if defined(__GNUC__)
 		size_t o;
 		size_t p;
-		if (_mul_overflow(p_elements, sizeof(T), &o)) {
+		if (__builtin_mul_overflow(p_elements, sizeof(T), &o)) {
 			*out = 0;
 			return false;
 		}
 		*out = next_power_of_2(o);
-		if (_add_overflow(o, static_cast<size_t>(32), &p)) return false; //no longer allocated here
+		if (__builtin_add_overflow(o, static_cast<size_t>(32), &p)) {
+			return false; // No longer allocated here.
+		}
 		return true;
 #else
 		// Speed is more important than correctness here, do the operations unchecked
-		// and hope the best
+		// and hope for the best.
 		*out = _get_alloc_size(p_elements);
 		return true;
 #endif
diff --git a/core/error_macros.h b/core/error_macros.h
index e4d7609e04..8818dcbe77 100644
--- a/core/error_macros.h
+++ b/core/error_macros.h
@@ -502,11 +502,11 @@ void _err_print_index_error(const char *p_function, const char *p_file, int p_li
  *
  * The current function returns `m_retval`.
  */
-#define ERR_FAIL_V(m_retval)                                                                                       \
-	if (1) {                                                                                                       \
-		_err_print_error(FUNCTION_STR, __FILE__, __LINE__, "Method/Function Failed, returning: " __STR(m_retval)); \
-		return m_retval;                                                                                           \
-	} else                                                                                                         \
+#define ERR_FAIL_V(m_retval)                                                                                      \
+	if (1) {                                                                                                      \
+		_err_print_error(FUNCTION_STR, __FILE__, __LINE__, "Method/Function Failed, returning: " _STR(m_retval)); \
+		return m_retval;                                                                                          \
+	} else                                                                                                        \
 		((void)0)
 
 /**
@@ -515,11 +515,11 @@ void _err_print_index_error(const char *p_function, const char *p_file, int p_li
  *
  * Prints `m_msg`, and the current function returns `m_retval`.
  */
-#define ERR_FAIL_V_MSG(m_retval, m_msg)                                                                                              \
-	if (1) {                                                                                                                         \
-		_err_print_error(FUNCTION_STR, __FILE__, __LINE__, "Method/Function Failed, returning: " __STR(m_retval), DEBUG_STR(m_msg)); \
-		return m_retval;                                                                                                             \
-	} else                                                                                                                           \
+#define ERR_FAIL_V_MSG(m_retval, m_msg)                                                                                             \
+	if (1) {                                                                                                                        \
+		_err_print_error(FUNCTION_STR, __FILE__, __LINE__, "Method/Function Failed, returning: " _STR(m_retval), DEBUG_STR(m_msg)); \
+		return m_retval;                                                                                                            \
+	} else                                                                                                                          \
 		((void)0)
 
 /**
diff --git a/core/math/random_pcg.h b/core/math/random_pcg.h
index ac65ce3509..8fd5a056fa 100644
--- a/core/math/random_pcg.h
+++ b/core/math/random_pcg.h
@@ -37,10 +37,10 @@
 
 #include "thirdparty/misc/pcg.h"
 
-#if defined(__GNUC__) || (_llvm_has_builtin(__builtin_clz))
+#if defined(__GNUC__)
 #define CLZ32(x) __builtin_clz(x)
 #elif defined(_MSC_VER)
-#include "intrin.h"
+#include <intrin.h>
 static int __bsr_clz32(uint32_t x) {
 	unsigned long index;
 	_BitScanReverse(&index, x);
@@ -50,11 +50,11 @@ static int __bsr_clz32(uint32_t x) {
 #else
 #endif
 
-#if defined(__GNUC__) || (_llvm_has_builtin(__builtin_ldexp) && _llvm_has_builtin(__builtin_ldexpf))
+#if defined(__GNUC__)
 #define LDEXP(s, e) __builtin_ldexp(s, e)
 #define LDEXPF(s, e) __builtin_ldexpf(s, e)
 #else
-#include "math.h"
+#include <math.h>
 #define LDEXP(s, e) ldexp(s, e)
 #define LDEXPF(s, e) ldexp(s, e)
 #endif
diff --git a/core/typedefs.h b/core/typedefs.h
index 5376b0718a..bafbffcded 100644
--- a/core/typedefs.h
+++ b/core/typedefs.h
@@ -37,60 +37,41 @@
  * Basic definitions and simple functions to be used everywhere.
  */
 
+// Include first in case the platform needs to pre-define/include some things.
 #include "platform_config.h"
 
+// Should be available everywhere.
+#include "core/error_list.h"
+#include "core/int_types.h"
+
+// Turn argument to string constant:
+// https://gcc.gnu.org/onlinedocs/cpp/Stringizing.html#Stringizing
 #ifndef _STR
 #define _STR(m_x) #m_x
 #define _MKSTR(m_x) _STR(m_x)
 #endif
 
-//should always inline no matter what
+// Should always inline no matter what.
 #ifndef _ALWAYS_INLINE_
-
-#if defined(__GNUC__) && (__GNUC__ >= 4)
-#define _ALWAYS_INLINE_ __attribute__((always_inline)) inline
-#elif defined(__llvm__)
+#if defined(__GNUC__)
 #define _ALWAYS_INLINE_ __attribute__((always_inline)) inline
 #elif defined(_MSC_VER)
 #define _ALWAYS_INLINE_ __forceinline
 #else
 #define _ALWAYS_INLINE_ inline
 #endif
-
 #endif
 
-//should always inline, except in some cases because it makes debugging harder
+// Should always inline, except in debug builds because it makes debugging harder.
 #ifndef _FORCE_INLINE_
-
 #ifdef DISABLE_FORCED_INLINE
 #define _FORCE_INLINE_ inline
 #else
 #define _FORCE_INLINE_ _ALWAYS_INLINE_
 #endif
-
 #endif
 
-//custom, gcc-safe offsetof, because gcc complains a lot.
-template <class T>
-T *_nullptr() {
-	T *t = NULL;
-	return t;
-}
-
-#define OFFSET_OF(st, m) \
-	((size_t)((char *)&(_nullptr<st>()->m) - (char *)0))
-/**
- * Some platforms (devices) don't define NULL
- */
-
-#ifndef NULL
-#define NULL 0
-#endif
-
-/**
- * Windows badly defines a lot of stuff we'll never use. Undefine it.
- */
-
+// Windows badly defines a lot of stuff we'll never use. Undefine it.
 #ifdef _WIN32
 #undef min // override standard definition
 #undef max // override standard definition
@@ -105,18 +86,11 @@ T *_nullptr() {
 #undef CONNECT_DEFERRED // override from Windows SDK, clashes with Object enum
 #endif
 
-#include "core/int_types.h"
-
-#include "core/error_list.h"
-
-/** Generic ABS function, for math uses please use Math::abs */
-
+// Generic ABS function, for math uses please use Math::abs.
 #ifndef ABS
 #define ABS(m_v) (((m_v) < 0) ? (-(m_v)) : (m_v))
 #endif
 
-#define ABSDIFF(x, y) (((x) < (y)) ? ((y) - (x)) : ((x) - (y)))
-
 #ifndef SGN
 #define SGN(m_v) (((m_v) < 0) ? (-1.0) : (+1.0))
 #endif
@@ -133,49 +107,24 @@ T *_nullptr() {
 #define CLAMP(m_a, m_min, m_max) (((m_a) < (m_min)) ? (m_min) : (((m_a) > (m_max)) ? m_max : m_a))
 #endif
 
-/** Generic swap template */
+// Generic swap template.
 #ifndef SWAP
-
 #define SWAP(m_x, m_y) __swap_tmpl((m_x), (m_y))
 template <class T>
 inline void __swap_tmpl(T &x, T &y) {
-
 	T aux = x;
 	x = y;
 	y = aux;
 }
+#endif // SWAP
 
-#endif //swap
-
-/* clang-format off */
-#define HEX2CHR(m_hex) \
-	((m_hex >= '0' && m_hex <= '9') ? (m_hex - '0') : \
-	((m_hex >= 'A' && m_hex <= 'F') ? (10 + m_hex - 'A') : \
-	((m_hex >= 'a' && m_hex <= 'f') ? (10 + m_hex - 'a') : 0)))
-/* clang-format on */
-
-// Macro to check whether we are compiled by clang
-// and we have a specific builtin
-#if defined(__llvm__) && defined(__has_builtin)
-#define _llvm_has_builtin(x) __has_builtin(x)
-#else
-#define _llvm_has_builtin(x) 0
-#endif
-
-#if (defined(__GNUC__) && (__GNUC__ >= 5)) || _llvm_has_builtin(__builtin_mul_overflow)
-#define _mul_overflow __builtin_mul_overflow
-#endif
-
-#if (defined(__GNUC__) && (__GNUC__ >= 5)) || _llvm_has_builtin(__builtin_add_overflow)
-#define _add_overflow __builtin_add_overflow
-#endif
-
-/** Function to find the next power of 2 to an integer */
+/* Functions to handle powers of 2 and shifting. */
 
+// Function to find the next power of 2 to an integer.
 static _FORCE_INLINE_ unsigned int next_power_of_2(unsigned int x) {
-
-	if (x == 0)
+	if (x == 0) {
 		return 0;
+	}
 
 	--x;
 	x |= x >> 1;
@@ -187,8 +136,8 @@ static _FORCE_INLINE_ unsigned int next_power_of_2(unsigned int x) {
 	return ++x;
 }
 
+// Function to find the previous power of 2 to an integer.
 static _FORCE_INLINE_ unsigned int previous_power_of_2(unsigned int x) {
-
 	x |= x >> 1;
 	x |= x >> 2;
 	x |= x >> 4;
@@ -197,40 +146,45 @@ static _FORCE_INLINE_ unsigned int previous_power_of_2(unsigned int x) {
 	return x - (x >> 1);
 }
 
+// Function to find the closest power of 2 to an integer.
 static _FORCE_INLINE_ unsigned int closest_power_of_2(unsigned int x) {
-
 	unsigned int nx = next_power_of_2(x);
 	unsigned int px = previous_power_of_2(x);
 	return (nx - x) > (x - px) ? px : nx;
 }
 
-// We need this definition inside the function below.
-static inline int get_shift_from_power_of_2(unsigned int p_pixel);
+// Get a shift value from a power of 2.
+static inline int get_shift_from_power_of_2(unsigned int p_bits) {
+	for (unsigned int i = 0; i < 32; i++) {
+		if (p_bits == (unsigned int)(1 << i)) {
+			return i;
+		}
+	}
+
+	return -1;
+}
 
 template <class T>
 static _FORCE_INLINE_ T nearest_power_of_2_templated(T x) {
-
 	--x;
 
 	// The number of operations on x is the base two logarithm
-	// of the p_number of bits in the type. Add three to account
+	// of the number of bits in the type. Add three to account
 	// for sizeof(T) being in bytes.
 	size_t num = get_shift_from_power_of_2(sizeof(T)) + 3;
 
-	// If the compiler is smart, it unrolls this loop
-	// If its dumb, this is a bit slow.
-	for (size_t i = 0; i < num; i++)
+	// If the compiler is smart, it unrolls this loop.
+	// If it's dumb, this is a bit slow.
+	for (size_t i = 0; i < num; i++) {
 		x |= x >> (1 << i);
+	}
 
 	return ++x;
 }
 
-/** Function to find the nearest (bigger) power of 2 to an integer */
-
+// Function to find the nearest (bigger) power of 2 to an integer.
 static inline unsigned int nearest_shift(unsigned int p_number) {
-
 	for (int i = 30; i >= 0; i--) {
-
 		if (p_number & (1 << i))
 			return i + 1;
 	}
@@ -238,41 +192,20 @@ static inline unsigned int nearest_shift(unsigned int p_number) {
 	return 0;
 }
 
-/** get a shift value from a power of 2 */
-static inline int get_shift_from_power_of_2(unsigned int p_pixel) {
-	// return a GL_TEXTURE_SIZE_ENUM
-
-	for (unsigned int i = 0; i < 32; i++) {
-
-		if (p_pixel == (unsigned int)(1 << i))
-			return i;
-	}
-
-	return -1;
-}
-
-/** Swap 16 bits value for endianness */
-#if defined(__GNUC__) || _llvm_has_builtin(__builtin_bswap16)
+// Swap 16, 32 and 64 bits value for endianness.
+#if defined(__GNUC__)
 #define BSWAP16(x) __builtin_bswap16(x)
+#define BSWAP32(x) __builtin_bswap32(x)
+#define BSWAP64(x) __builtin_bswap64(x)
 #else
 static inline uint16_t BSWAP16(uint16_t x) {
 	return (x >> 8) | (x << 8);
 }
-#endif
 
-/** Swap 32 bits value for endianness */
-#if defined(__GNUC__) || _llvm_has_builtin(__builtin_bswap32)
-#define BSWAP32(x) __builtin_bswap32(x)
-#else
 static inline uint32_t BSWAP32(uint32_t x) {
 	return ((x << 24) | ((x << 8) & 0x00FF0000) | ((x >> 8) & 0x0000FF00) | (x >> 24));
 }
-#endif
 
-/** Swap 64 bits value for endianness */
-#if defined(__GNUC__) || _llvm_has_builtin(__builtin_bswap64)
-#define BSWAP64(x) __builtin_bswap64(x)
-#else
 static inline uint64_t BSWAP64(uint64_t x) {
 	x = (x & 0x00000000FFFFFFFF) << 32 | (x & 0xFFFFFFFF00000000) >> 32;
 	x = (x & 0x0000FFFF0000FFFF) << 16 | (x & 0xFFFF0000FFFF0000) >> 16;
@@ -281,40 +214,24 @@ static inline uint64_t BSWAP64(uint64_t x) {
 }
 #endif
 
-/** When compiling with RTTI, we can add an "extra"
- * layer of safeness in many operations, so dynamic_cast
- * is used besides casting by enum.
- */
-
+// Generic comparator used in Map, List, etc.
 template <class T>
 struct Comparator {
-
 	_ALWAYS_INLINE_ bool operator()(const T &p_a, const T &p_b) const { return (p_a < p_b); }
 };
 
+// Global lock macro, relies on the static Mutex::_global_mutex.
 void _global_lock();
 void _global_unlock();
 
 struct _GlobalLock {
-
 	_GlobalLock() { _global_lock(); }
 	~_GlobalLock() { _global_unlock(); }
 };
 
 #define GLOBAL_LOCK_FUNCTION _GlobalLock _global_lock_;
 
-#ifdef NO_SAFE_CAST
-#define SAFE_CAST static_cast
-#else
-#define SAFE_CAST dynamic_cast
-#endif
-
-#define MT_SAFE
-
-#define __STRX(m_index) #m_index
-#define __STR(m_index) __STRX(m_index)
-
-#ifdef __GNUC__
+#if defined(__GNUC__)
 #define likely(x) __builtin_expect(!!(x), 1)
 #define unlikely(x) __builtin_expect(!!(x), 0)
 #else
@@ -330,14 +247,12 @@ struct _GlobalLock {
 #define _PRINTF_FORMAT_ATTRIBUTE_2_3
 #endif
 
-/** This is needed due to a strange OpenGL API that expects a pointer
- *  type for an argument that is actually an offset.
- */
+// This is needed due to a strange OpenGL API that expects a pointer
+// type for an argument that is actually an offset.
 #define CAST_INT_TO_UCHAR_PTR(ptr) ((uint8_t *)(uintptr_t)(ptr))
 
 // Home-made index sequence trick, so it can be used everywhere without the costly include of std::tuple.
 // https://stackoverflow.com/questions/15014096/c-index-of-type-during-variadic-template-expansion
-
 template <size_t... Is>
 struct IndexSequence {};
 
diff --git a/editor/collada/collada.cpp b/editor/collada/collada.cpp
index 231173e459..cf39abdc53 100644
--- a/editor/collada/collada.cpp
+++ b/editor/collada/collada.cpp
@@ -2194,7 +2194,11 @@ void Collada::_merge_skeletons(VisualScene *p_vscene, Node *p_node) {
 
 				ERR_CONTINUE(!state.scene_map.has(nodeid)); //weird, it should have it...
 
-				NodeJoint *nj = SAFE_CAST<NodeJoint *>(state.scene_map[nodeid]);
+#ifdef NO_SAFE_CAST
+				NodeJoint *nj = static_cast<NodeJoint *>(state.scene_map[nodeid]);
+#else
+				NodeJoint *nj = dynamic_cast<NodeJoint *>(state.scene_map[nodeid]);
+#endif
 				ERR_CONTINUE(!nj); //broken collada
 				ERR_CONTINUE(!nj->owner); //weird, node should have a skeleton owner
 
@@ -2366,7 +2370,11 @@ bool Collada::_move_geometry_to_skeletons(VisualScene *p_vscene, Node *p_node, L
 			String nodeid = ng->skeletons[0];
 
 			ERR_FAIL_COND_V(!state.scene_map.has(nodeid), false); //weird, it should have it...
-			NodeJoint *nj = SAFE_CAST<NodeJoint *>(state.scene_map[nodeid]);
+#ifdef NO_SAFE_CAST
+			NodeJoint *nj = static_cast<NodeJoint *>(state.scene_map[nodeid]);
+#else
+			NodeJoint *nj = dynamic_cast<NodeJoint *>(state.scene_map[nodeid]);
+#endif
 			ERR_FAIL_COND_V(!nj, false);
 			ERR_FAIL_COND_V(!nj->owner, false); //weird, node should have a skeleton owner
 
diff --git a/platform/x11/os_x11.cpp b/platform/x11/os_x11.cpp
index c74981fd55..ddb5237d1b 100644
--- a/platform/x11/os_x11.cpp
+++ b/platform/x11/os_x11.cpp
@@ -2012,8 +2012,10 @@ void OS_X11::handle_key_event(XKeyEvent *p_event, bool p_echo) {
 			// is correct, but the xorg developers are
 			// not very helpful today.
 
-			::Time tresh = ABSDIFF(peek_event.xkey.time, xkeyevent->time);
-			if (peek_event.type == KeyPress && tresh < 5) {
+#define ABSDIFF(x, y) (((x) < (y)) ? ((y) - (x)) : ((x) - (y)))
+			::Time threshold = ABSDIFF(peek_event.xkey.time, xkeyevent->time);
+#undef ABSDIFF
+			if (peek_event.type == KeyPress && threshold < 5) {
 				KeySym rk;
 				XLookupString((XKeyEvent *)&peek_event, str, 256, &rk, NULL);
 				if (rk == keysym_keycode) {