shithub: rgbds

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Improve helpers.h

Use C11 standard _Noreturn instead of attributes (except, of course, MSVC)
Remove unused helpers
Avoid trapping in release builds, in favor of just unreachability
Improve shim when __builtin_* are not available

--- a/include/asm/warning.h

+++ b/include/asm/warning.h

@@ -55,7 +55,7 @@

  * It is also used when the assembler goes into an invalid state (for example,

  * when it fails to allocate memory).

  */

-noreturn_ void fatalerror(const char *fmt, ...);

+_Noreturn void fatalerror(const char *fmt, ...);

 /*

  * Used for errors that make it impossible to assemble correctly, but don't

--- a/include/extern/err.h

+++ b/include/extern/err.h

@@ -34,10 +34,10 @@

 void warnx(const char *fmt, ...) format_(printf, 1, 2);

 void vwarnx(const char *fmt, va_list ap) format_(printf, 1, 0);

-noreturn_ void err(int status, const char *fmt, ...) format_(printf, 2, 3);

-noreturn_ void verr(int status, const char *fmt, va_list ap) format_(printf, 2, 0);

-noreturn_ void errx(int status, const char *fmt, ...) format_(printf, 2, 3);

-noreturn_ void verrx(int status, const char *fmt, va_list ap) format_(printf, 2, 0);

+_Noreturn void err(int status, const char *fmt, ...) format_(printf, 2, 3);

+_Noreturn void verr(int status, const char *fmt, va_list ap) format_(printf, 2, 0);

+_Noreturn void errx(int status, const char *fmt, ...) format_(printf, 2, 3);

+_Noreturn void verrx(int status, const char *fmt, va_list ap) format_(printf, 2, 0);

 #endif /* ERR_IN_LIBC */

--- a/include/helpers.h

+++ b/include/helpers.h

@@ -9,21 +9,30 @@

 #ifndef HELPERS_H

 #define HELPERS_H

-#ifdef __GNUC__

-	/* GCC or compatible */

+// Of course, MSVC does not support C11, so no _Noreturn there...

+#ifdef _MSC_VER

+	#define _Noreturn __declspec(noreturn)

+#endif

+

+// 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 noreturn_	__attribute__ ((noreturn))

-	#define trap_		__builtin_trap()

+	// In release builds, define "unreachable" as such, but trap in debug builds

+	#ifdef NDEBUG

+		#define unreachable_	__builtin_unreachable

+	#else

+		#define unreachable_	__builtin_trap

+	#endif

 #else

-	/* Unsupported, but no need to throw a fit */

+	// Unsupported, but no need to throw a fit

 	#define format_(archetype, str_index, first_arg)

-	#define noreturn_

-	#define unused_

-	#define trap_

+	// This seems to generate similar code to __builtin_unreachable, despite different semantics

+	// Note that executing this is undefined behavior (declared _Noreturn, but does return)

+	static inline _Noreturn unreachable_(void) {}

 #endif

-/* Macros for stringification */

+// Macros for stringification

 #define STR(x) #x

 #define EXPAND_AND_STR(x) STR(x)

--- a/include/link/main.h

+++ b/include/link/main.h

@@ -66,7 +66,7 @@

 void error(struct FileStackNode const *where, uint32_t lineNo,

 	   char const *fmt, ...) format_(printf, 3, 4);

-noreturn_ void fatal(struct FileStackNode const *where, uint32_t lineNo,

+_Noreturn void fatal(struct FileStackNode const *where, uint32_t lineNo,

 		     char const *fmt, ...) format_(printf, 3, 4);

 /**

--- a/src/asm/warning.c

+++ b/src/asm/warning.c

@@ -222,7 +222,7 @@

 	nbErrors++;

 }

-noreturn_ void fatalerror(const char *fmt, ...)

+_Noreturn void fatalerror(const char *fmt, ...)

 {

 	va_list args;

@@ -250,7 +250,7 @@

 		return;

 	case WARNING_DEFAULT:

-		trap_;

+		unreachable_();

 		/* Not reached */

 	case WARNING_ENABLED:

--- a/src/extern/err.c

+++ b/src/extern/err.c

@@ -34,7 +34,7 @@

 	putc('\n', stderr);

 }

-noreturn_ void rgbds_verr(int status, const char *fmt, va_list ap)

+_Noreturn void rgbds_verr(int status, const char *fmt, va_list ap)

 {

 	fprintf(stderr, "error: ");

 	if (fmt) {

@@ -46,7 +46,7 @@

 	exit(status);

 }

-noreturn_ void rgbds_verrx(int status, const char *fmt, va_list ap)

+_Noreturn void rgbds_verrx(int status, const char *fmt, va_list ap)

 {

 	fprintf(stderr, "error");

 	if (fmt) {

@@ -75,7 +75,7 @@

 	va_end(ap);

 }

-noreturn_ void rgbds_err(int status, const char *fmt, ...)

+_Noreturn void rgbds_err(int status, const char *fmt, ...)

 {

 	va_list ap;

@@ -84,7 +84,7 @@

 	va_end(ap);

 }

-noreturn_ void rgbds_errx(int status, const char *fmt, ...)

+_Noreturn void rgbds_errx(int status, const char *fmt, ...)

 {

 	va_list ap;

--- a/src/link/assign.c

+++ b/src/link/assign.c

@@ -439,7 +439,7 @@

 			return;

 	}

-	trap_;

+	unreachable_();

 }

 void assign_Cleanup(void)

--- a/src/link/main.c

+++ b/src/link/main.c

@@ -99,7 +99,7 @@

 		nbErrors++;

 }

-noreturn_ void fatal(struct FileStackNode const *where, uint32_t lineNo, char const *fmt, ...)

+_Noreturn void fatal(struct FileStackNode const *where, uint32_t lineNo, char const *fmt, ...)

 {

 	va_list ap;

--- a/src/link/script.c

+++ b/src/link/script.c

@@ -318,7 +318,7 @@

 {

 	switch (command) {

 	case COMMAND_INVALID:

-		trap_;

+		unreachable_();

 	case COMMAND_ORG:

 		break;

@@ -391,12 +391,12 @@

 		switch (parserState) {

 		case PARSER_FIRSTTIME:

-			trap_;

+			unreachable_();

 		case PARSER_LINESTART:

 			switch (token->type) {

 			case TOKEN_INVALID:

-				trap_;

+				unreachable_();

 			case TOKEN_EOF:

 				if (!popFile())

--- a/src/link/section.c

+++ b/src/link/section.c

@@ -108,7 +108,7 @@

 		break;

 	case SECTION_NORMAL:

-		trap_;

+		unreachable_();

 	}

 	other->nextu = target->nextu;