Use standard attribute syntax instead of IBM __attribute__

Move format attrs to proper standard location

For some reason, GCC 13 is more lax than earlier versions...

include/asm/warning.hpp

@@ -62,7 +62,7 @@ void processWarningFlag(char const *flag);
  * Used to warn the user about problems that don't prevent the generation of
  * valid code.
  */
-void warning(WarningID id, char const *fmt, ...) format_(printf, 2, 3);
+[[gnu::format(printf, 2, 3)]] void warning(WarningID id, char const *fmt, ...);
 
 /*
  * Used for errors that compromise the whole assembly process by affecting the
@@ -71,7 +71,7 @@ void warning(WarningID id, char const *fmt, ...) format_(printf, 2, 3);
  * It is also used when the assembler goes into an invalid state (for example,
  * when it fails to allocate memory).
  */
-[[noreturn]] void fatalerror(char const *fmt, ...) format_(printf, 1, 2);
+[[gnu::format(printf, 1, 2), noreturn]] void fatalerror(char const *fmt, ...);
 
 /*
  * Used for errors that make it impossible to assemble correctly, but don't
@@ -79,6 +79,6 @@ void warning(WarningID id, char const *fmt, ...) format_(printf, 2, 3);
  * get a list of all errors at the end, making it easier to fix all of them at
  * once.
  */
-void error(char const *fmt, ...) format_(printf, 1, 2);
+[[gnu::format(printf, 1, 2)]] void error(char const *fmt, ...);
 
 #endif // WARNING_H

include/error.hpp

@@ -3,16 +3,15 @@
 #ifndef RGBDS_ERROR_H
 #define RGBDS_ERROR_H
 
-#include "helpers.hpp"
 #include "platform.hpp"
 
 extern "C" {
 
-void warn(char const *fmt...) format_(printf, 1, 2);
-void warnx(char const *fmt, ...) format_(printf, 1, 2);
+[[gnu::format(printf, 1, 2)]] void warn(char const *fmt...);
+[[gnu::format(printf, 1, 2)]] void warnx(char const *fmt, ...);
 
-[[noreturn]] void err(char const *fmt, ...) format_(printf, 1, 2);
-[[noreturn]] void errx(char const *fmt, ...) format_(printf, 1, 2);
+[[gnu::format(printf, 1, 2), noreturn]] void err(char const *fmt, ...);
+[[gnu::format(printf, 1, 2), noreturn]] void errx(char const *fmt, ...);
 }
 
 #endif // RGBDS_ERROR_H

include/gfx/main.hpp

@@ -58,7 +58,7 @@ struct Options {
 	static constexpr uint8_t VERB_DEBUG = 4;    // Internals are logged
 	static constexpr uint8_t VERB_UNMAPPED = 5; // Unused so far
 	static constexpr uint8_t VERB_VVVVVV = 6;   // What, can't I have a little fun?
-	format_(printf, 3, 4) void verbosePrint(uint8_t level, char const *fmt, ...) const;
+	[[gnu::format(printf, 3, 4)]] void verbosePrint(uint8_t level, char const *fmt, ...) const;
 
 	mutable bool hasTransparentPixels = false;
 	uint8_t maxOpaqueColors() const { return nbColorsPerPal - hasTransparentPixels; }
@@ -73,11 +73,11 @@ extern Options options;
 /*
  * Prints a warning, and does not change the error count
  */
-void warning(char const *fmt, ...) format_(printf, 1, 2);
+[[gnu::format(printf, 1, 2)]] void warning(char const *fmt, ...);
 /*
  * Prints an error, and increments the error count
  */
-void error(char const *fmt, ...) format_(printf, 1, 2);
+[[gnu::format(printf, 1, 2)]] void error(char const *fmt, ...);
 /*
  * Prints an error, and increments the error count
  * Does not take format arguments so `format_` and `-Wformat-security` won't complain about
@@ -87,7 +87,7 @@ void errorMessage(char const *msg);
 /*
  * Prints a fatal error, increments the error count, and gives up
  */
-[[noreturn]] void fatal(char const *fmt, ...) format_(printf, 1, 2);
+[[gnu::format(printf, 1, 2), noreturn]] void fatal(char const *fmt, ...);
 
 struct Palette {
 	// An array of 4 GBC-native (RGB555) colors

include/helpers.hpp

@@ -5,9 +5,6 @@
 
 // Ideally, we'd use `__has_attribute` and `__has_builtin`, but these were only introduced in GCC 9
 #ifdef __GNUC__ // GCC or compatible
-	#define format_(archetype, str_index, first_arg) \
-		__attribute__((format(archetype, str_index, first_arg)))
-	#define attr_(...) __attribute__((__VA_ARGS__))
 	// In release builds, define "unreachable" as such, but trap in debug builds
 	#ifdef NDEBUG
 		#define unreachable_ __builtin_unreachable
@@ -15,9 +12,6 @@
 		#define unreachable_ __builtin_trap
 	#endif
 #else
-	// Unsupported, but no need to throw a fit
-	#define format_(archetype, str_index, first_arg)
-	#define attr_(...)
 // This seems to generate similar code to __builtin_unreachable, despite different semantics
 // Note that executing this is undefined behavior (declared [[noreturn]], but does return)
 [[noreturn]] static inline void unreachable_() {

include/link/main.hpp

@@ -59,10 +59,11 @@ struct FileStackNode {
 	std::string const &dump(uint32_t curLineNo) const;
 };
 
-void warning(FileStackNode const *where, uint32_t lineNo, char const *fmt, ...)
-    format_(printf, 3, 4);
-void error(FileStackNode const *where, uint32_t lineNo, char const *fmt, ...) format_(printf, 3, 4);
-[[noreturn]] void fatal(FileStackNode const *where, uint32_t lineNo, char const *fmt, ...)
-    format_(printf, 3, 4);
+[[gnu::format(printf, 3, 4)]] void
+    warning(FileStackNode const *where, uint32_t lineNo, char const *fmt, ...);
+[[gnu::format(printf, 3, 4)]] void
+    error(FileStackNode const *where, uint32_t lineNo, char const *fmt, ...);
+[[gnu::format(printf, 3, 4), noreturn]] void
+    fatal(FileStackNode const *where, uint32_t lineNo, char const *fmt, ...);
 
 #endif // RGBDS_LINK_MAIN_H

src/asm/format.cpp

@@ -45,7 +45,7 @@ void FormatSpec::useCharacter(int c) {
 	case '0':
 		if (state < FORMAT_WIDTH)
 			padZero = true;
-		// fallthrough
+		[[fallthrough]];
 	case '1':
 	case '2':
 	case '3':

src/asm/lexer.cpp

@@ -864,7 +864,7 @@ static void discardBlockComment() {
 		case '\r':
 			// Handle CRLF before nextLine() since shiftChar updates colNo
 			handleCRLF(c);
-			// fallthrough
+			[[fallthrough]];
 		case '\n':
 			if (lexerState->expansions.empty())
 				nextLine();
@@ -879,7 +879,7 @@ static void discardBlockComment() {
 				shiftChar();
 				return;
 			}
-			// fallthrough
+			[[fallthrough]];
 		default:
 			continue;
 		}
@@ -1216,7 +1216,7 @@ static void appendEscapedSubstring(std::string &yylval, std::string const &str)
 		case '"':
 		case '{':
 			yylval += '\\';
-			// fallthrough
+			[[fallthrough]];
 		default:
 			yylval += c;
 			break;
@@ -1515,7 +1515,7 @@ static Token yylex_NORMAL() {
 
 		case ';':
 			discardComment();
-			// fallthrough
+			[[fallthrough]];
 		case ' ':
 		case '\t':
 			break;
@@ -1729,7 +1729,7 @@ static Token yylex_NORMAL() {
 
 		case '\r':
 			handleCRLF(c);
-			// fallthrough
+			[[fallthrough]];
 		case '\n':
 			return Token(T_(NEWLINE));
 
@@ -1751,7 +1751,7 @@ static Token yylex_NORMAL() {
 				shiftChar();
 				return Token(T_(STRING), readString(true));
 			}
-			// fallthrough
+			[[fallthrough]];
 
 			// Handle identifiers... or report garbage characters
 
@@ -1846,7 +1846,7 @@ static Token yylex_RAW() {
 		case ';': // Comments inside macro args
 			discardComment();
 			c = peek();
-			// fallthrough
+			[[fallthrough]];
 		case '\r': // End of line
 		case '\n':
 		case EOF:
@@ -1920,7 +1920,7 @@ backslash:
 				error("Illegal character escape %s\n", printChar(c));
 				break;
 			}
-			// fallthrough
+			[[fallthrough]];
 
 		default: // Regular characters will just get copied
 append:

src/asm/main.cpp

@@ -198,7 +198,7 @@ int main(int argc, char *argv[]) {
 		// introduced to better match the `-I dir` option of gcc and clang.
 		case 'i':
 			warning(WARNING_OBSOLETE, "`-i` is deprecated; use `-I`\n");
-			// fallthrough
+			[[fallthrough]];
 		case 'I':
 			fstk_AddIncludePath(musl_optarg);
 			break;

src/asm/section.cpp

@@ -47,7 +47,7 @@ std::optional<std::string> currentLoadScope = std::nullopt;
 int32_t loadOffset; // Offset into the LOAD section's parent (see sect_GetOutputOffset)
 
 // A quick check to see if we have an initialized section
-attr_(warn_unused_result) static bool checksection() {
+[[nodiscard]] static bool checksection() {
 	if (currentSection)
 		return true;
 
@@ -57,7 +57,7 @@ attr_(warn_unused_result) static bool checksection() {
 
 // A quick check to see if we have an initialized section that can contain
 // this much initialized data
-attr_(warn_unused_result) static bool checkcodesection() {
+[[nodiscard]] static bool checkcodesection() {
 	if (!checksection())
 		return false;
 
@@ -71,7 +71,7 @@ attr_(warn_unused_result) static bool checkcodesection() {
 	return false;
 }
 
-attr_(warn_unused_result) static bool checkSectionSize(Section const &sect, uint32_t size) {
+[[nodiscard]] static bool checkSectionSize(Section const &sect, uint32_t size) {
 	uint32_t maxSize = sectionTypeInfo[sect.type].size;
 
 	// If the new size is reasonable, keep going
@@ -88,7 +88,7 @@ attr_(warn_unused_result) static bool checkSectionSize(Section const &sect, uint
 }
 
 // Check if the section has grown too much.
-attr_(warn_unused_result) static bool reserveSpace(uint32_t delta_size) {
+[[nodiscard]] static bool reserveSpace(uint32_t delta_size) {
 	// This check is here to trap broken code that generates sections that are too big and to
 	// prevent the assembler from generating huge object files or trying to allocate too much
 	// memory.

src/fix/main.cpp

@@ -76,7 +76,7 @@ static void printUsage() {
 
 static uint8_t nbErrors;
 
-static format_(printf, 1, 2) void report(char const *fmt, ...) {
+[[gnu::format(printf, 1, 2)]] static void report(char const *fmt, ...) {
 	va_list ap;
 
 	va_start(ap, fmt);
@@ -465,7 +465,7 @@ static MbcType parseMBC(char const *name) {
 			static_assert(MBC1 + 2 == MBC1_RAM_BATTERY, "Enum sanity check failed!");
 			static_assert(MMM01 + 1 == MMM01_RAM, "Enum sanity check failed!");
 			static_assert(MMM01 + 2 == MMM01_RAM_BATTERY, "Enum sanity check failed!");
-			// fallthrough
+			[[fallthrough]];
 		case MBC1:
 		case MMM01:
 			if (features == RAM)

src/link/sdas_obj.cpp

@@ -50,11 +50,11 @@ retry:
 		do {
 			firstChar = getc(file);
 		} while (firstChar != EOF && firstChar != '\r' && firstChar != '\n');
-		// fallthrough
+		[[fallthrough]];
 	case '\r':
 		if (firstChar == '\r' && getc(file) != '\n')
 			consumeLF(where, lineNo, file);
-		// fallthrough
+		[[fallthrough]];
 	case '\n':
 		goto retry;
 	}
@@ -65,7 +65,7 @@ retry:
 		switch (c) {
 		case '\r':
 			consumeLF(where, lineNo, file);
-			// fallthrough
+			[[fallthrough]];
 		case '\n':
 		case EOF:
 			lineBuf.push_back('\0'); // Terminate the string (space was ensured above)