Refactoring and enhancements to RGBASM warnings (#1526)

* Allow a `no-` prefix to negate "meta" warnings
  (`-Wno-all`, `-Wno-extra`, `-Wno-everything`)
* Allow `-Wno-error=...` to override `-Werror`
  (including for "meta" warnings)

include/asm/warning.hpp

@@ -5,8 +5,6 @@
 
 extern unsigned int nbErrors, maxErrors;
 
-enum WarningState { WARNING_DEFAULT, WARNING_DISABLED, WARNING_ENABLED, WARNING_ERROR };
-
 enum WarningID {
 	WARNING_ASSERT,               // Assertions
 	WARNING_BACKWARDS_FOR,        // `for` loop with backwards range
@@ -26,10 +24,9 @@ enum WarningID {
 
 	NB_PLAIN_WARNINGS,
 
-// Warnings past this point are "parametric" warnings, only mapping to a single flag
+	// Warnings past this point are "parametric" warnings, only mapping to a single flag
-#define PARAM_WARNINGS_START NB_PLAIN_WARNINGS
 	// Treating string as number may lose some bits
-	WARNING_NUMERIC_STRING_1 = PARAM_WARNINGS_START,
+	WARNING_NUMERIC_STRING_1 = NB_PLAIN_WARNINGS,
 	WARNING_NUMERIC_STRING_2,
 	// Purging an exported symbol or label
 	WARNING_PURGE_1,
@@ -41,20 +38,24 @@ enum WarningID {
 	WARNING_UNMAPPED_CHAR_1,
 	WARNING_UNMAPPED_CHAR_2,
 
-	NB_PLAIN_AND_PARAM_WARNINGS,
-#define NB_PARAM_WARNINGS (NB_PLAIN_AND_PARAM_WARNINGS - PARAM_WARNINGS_START)
-
-// Warnings past this point are "meta" warnings
-#define META_WARNINGS_START NB_PLAIN_AND_PARAM_WARNINGS
-	WARNING_ALL = META_WARNINGS_START,
-	WARNING_EXTRA,
-	WARNING_EVERYTHING,
-
 	NB_WARNINGS,
-#define NB_META_WARNINGS (NB_WARNINGS - META_WARNINGS_START)
 };
 
-extern WarningState warningStates[NB_PLAIN_AND_PARAM_WARNINGS];
+enum WarningAbled { WARNING_DEFAULT, WARNING_ENABLED, WARNING_DISABLED };
+
+struct WarningState {
+	WarningAbled state;
+	WarningAbled error;
+
+	void update(WarningState other);
+};
+
+struct Diagnostics {
+	WarningState flagStates[NB_WARNINGS];
+	WarningState metaStates[NB_WARNINGS];
+};
+
+extern Diagnostics warningStates;
 extern bool warningsAreErrors;
 
 void processWarningFlag(char const *flag);

man/rgbasm.1

@@ -212,13 +212,19 @@ The following options alter the way warnings are processed.
 .Bl -tag -width Ds
 .It Fl Werror
 Make all warnings into errors.
+This can be negated as
+.Fl Wno-error
+to prevent turning all warnings into errors.
 .It Fl Werror=
-Make the specified warning into an error.
+Make the specified warning or meta warning into an error.
 A warning's name is appended
 .Pq example: Fl Werror=obsolete ,
 and this warning is implicitly enabled and turned into an error.
-This is an error if used with a meta warning, such as
+This can be negated as
-.Fl Werror=all .
+.Fl Wno-error=
+to prevent turning a specified warning into an error, even if
+.Fl Werror
+is in effect.
 .El
 .Pp
 The following warnings are
@@ -240,6 +246,10 @@ Note that each of these flag also has a negation (for example,
 .Fl Wcharmap-redef
 enables the warning that
 .Fl Wno-charmap-redef
+disables; and
+.Fl Wall
+enables every warning that
+.Fl Wno-all
 disables).
 Only the non-default flag is listed here.
 Ignoring the

src/asm/main.cpp

@@ -293,7 +293,7 @@ int main(int argc, char *argv[]) {
 			break;
 
 		case 'W':
-			processWarningFlag(musl_optarg);
+			opt_W(musl_optarg);
 			break;
 
 		case 'w':

src/asm/opt.cpp

@@ -13,8 +13,6 @@
 #include "asm/section.hpp"
 #include "asm/warning.hpp"
 
-static constexpr size_t numWarningStates = sizeof(warningStates);
-
 struct OptStackEntry {
 	char binary[2];
 	char gbgfx[4];
@@ -22,7 +20,7 @@ struct OptStackEntry {
 	uint8_t fillByte;
 	bool warningsAreErrors;
 	size_t maxRecursionDepth;
-	WarningState warningStates[numWarningStates];
+	Diagnostics warningStates;
 };
 
 static std::stack<OptStackEntry> stack;
@@ -160,7 +158,7 @@ void opt_Push() {
 
 	// Both of these pulled from warning.hpp
 	entry.warningsAreErrors = warningsAreErrors;
-	memcpy(entry.warningStates, warningStates, numWarningStates);
+	entry.warningStates = warningStates;
 
 	entry.maxRecursionDepth = maxRecursionDepth; // Pulled from fstack.h
 
@@ -184,5 +182,5 @@ void opt_Pop() {
 
 	// opt_W does not apply a whole warning state; it processes one flag string
 	warningsAreErrors = entry.warningsAreErrors;
-	memcpy(warningStates, entry.warningStates, numWarningStates);
+	warningStates = entry.warningStates;
 }

src/asm/warning.cpp

@@ -10,7 +10,7 @@
 #include <string.h>
 
 #include "error.hpp"
-#include "helpers.hpp" // QUOTEDSTRLEN
+#include "helpers.hpp"
 #include "itertools.hpp"
 
 #include "asm/fstack.hpp"
@@ -20,266 +20,163 @@
 unsigned int nbErrors = 0;
 unsigned int maxErrors = 0;
 
-static WarningState const defaultWarnings[ARRAY_SIZE(warningStates)] = {
+Diagnostics warningStates;
-    WARNING_ENABLED,  // WARNING_ASSERT
+bool warningsAreErrors;
-    WARNING_DISABLED, // WARNING_BACKWARDS_FOR
-    WARNING_DISABLED, // WARNING_BUILTIN_ARG
-    WARNING_DISABLED, // WARNING_CHARMAP_REDEF
-    WARNING_DISABLED, // WARNING_DIV
-    WARNING_DISABLED, // WARNING_EMPTY_DATA_DIRECTIVE
-    WARNING_DISABLED, // WARNING_EMPTY_MACRO_ARG
-    WARNING_DISABLED, // WARNING_EMPTY_STRRPL
-    WARNING_DISABLED, // WARNING_LARGE_CONSTANT
-    WARNING_DISABLED, // WARNING_MACRO_SHIFT
-    WARNING_ENABLED,  // WARNING_NESTED_COMMENT
-    WARNING_ENABLED,  // WARNING_OBSOLETE
-    WARNING_DISABLED, // WARNING_SHIFT
-    WARNING_DISABLED, // WARNING_SHIFT_AMOUNT
-    WARNING_ENABLED,  // WARNING_USER
 
-    WARNING_DISABLED, // WARNING_NUMERIC_STRING_1
+enum WarningLevel {
-    WARNING_DISABLED, // WARNING_NUMERIC_STRING_2
+	LEVEL_DEFAULT,    // Warnings that are enabled by default
-    WARNING_ENABLED,  // WARNING_PURGE_1
+	LEVEL_ALL,        // Warnings that probably indicate an error
-    WARNING_DISABLED, // WARNING_PURGE_2
+	LEVEL_EXTRA,      // Warnings that are less likely to indicate an error
-    WARNING_ENABLED,  // WARNING_TRUNCATION_1
+	LEVEL_EVERYTHING, // Literally every warning
-    WARNING_DISABLED, // WARNING_TRUNCATION_2
-    WARNING_ENABLED,  // WARNING_UNMAPPED_CHAR_1
-    WARNING_DISABLED, // WARNING_UNMAPPED_CHAR_2
 };
 
-WarningState warningStates[ARRAY_SIZE(warningStates)];
+struct WarningFlag {
+	char const *name;
+	WarningLevel level;
+};
 
-bool warningsAreErrors; // Set if `-Werror` was specified
+static const WarningFlag metaWarnings[] = {
-
+    {"all",        LEVEL_ALL       },
-static WarningState warningState(WarningID id) {
+    {"extra",      LEVEL_EXTRA     },
-	// Check if warnings are globally disabled
+    {"everything", LEVEL_EVERYTHING},
-	if (!warnings)
+};
-		return WARNING_DISABLED;
-
-	// Get the actual state
-	WarningState state = warningStates[id];
-
-	if (state == WARNING_DEFAULT)
-		// The state isn't set, grab its default state
-		state = defaultWarnings[id];
-
-	if (warningsAreErrors && state == WARNING_ENABLED)
-		state = WARNING_ERROR;
-
-	return state;
-}
-
-static char const * const warningFlags[NB_WARNINGS] = {
-    "assert",
-    "backwards-for",
-    "builtin-args",
-    "charmap-redef",
-    "div",
-    "empty-data-directive",
-    "empty-macro-arg",
-    "empty-strrpl",
-    "large-constant",
-    "macro-shift",
-    "nested-comment",
-    "obsolete",
-    "shift",
-    "shift-amount",
-    "user",
 
+static const WarningFlag warningFlags[NB_WARNINGS] = {
+    {"assert",               LEVEL_DEFAULT   },
+    {"backwards-for",        LEVEL_ALL       },
+    {"builtin-args",         LEVEL_ALL       },
+    {"charmap-redef",        LEVEL_ALL       },
+    {"div",                  LEVEL_EVERYTHING},
+    {"empty-data-directive", LEVEL_ALL       },
+    {"empty-macro-arg",      LEVEL_EXTRA     },
+    {"empty-strrpl",         LEVEL_ALL       },
+    {"large-constant",       LEVEL_ALL       },
+    {"macro-shift",          LEVEL_EXTRA     },
+    {"nested-comment",       LEVEL_DEFAULT   },
+    {"obsolete",             LEVEL_DEFAULT   },
+    {"shift",                LEVEL_EVERYTHING},
+    {"shift-amount",         LEVEL_EVERYTHING},
+    {"user",                 LEVEL_DEFAULT   },
     // Parametric warnings
-    "numeric-string",
+    {"numeric-string",       LEVEL_EVERYTHING},
-    "numeric-string",
+    {"numeric-string",       LEVEL_EVERYTHING},
-    "purge",
+    {"purge",                LEVEL_DEFAULT   },
-    "purge",
+    {"purge",                LEVEL_ALL       },
-    "truncation",
+    {"truncation",           LEVEL_DEFAULT   },
-    "truncation",
+    {"truncation",           LEVEL_EXTRA     },
-    "unmapped-char",
+    {"unmapped-char",        LEVEL_DEFAULT   },
-    "unmapped-char",
+    {"unmapped-char",        LEVEL_ALL       },
-
-    // Meta warnings
-    "all",
-    "extra",
-    "everything", // Especially useful for testing
 };
 
 static const struct {
-	char const *name;
+	WarningID firstID;
-	uint8_t nbLevels;
+	WarningID lastID;
 	uint8_t defaultLevel;
 } paramWarnings[] = {
-    {"numeric-string", 2, 1},
+    {WARNING_NUMERIC_STRING_1, WARNING_NUMERIC_STRING_2, 1},
-    {"purge",          2, 1},
+    {WARNING_PURGE_1,          WARNING_PURGE_2,          1},
-    {"truncation",     2, 2},
+    {WARNING_TRUNCATION_1,     WARNING_TRUNCATION_2,     2},
-    {"unmapped-char",  2, 1},
+    {WARNING_UNMAPPED_CHAR_1,  WARNING_UNMAPPED_CHAR_2,  1},
 };
 
-static bool tryProcessParamWarning(char const *flag, uint8_t param, WarningState state) {
+enum WarningBehavior { DISABLED, ENABLED, ERROR };
-	WarningID baseID = PARAM_WARNINGS_START;
 
-	for (size_t i = 0; i < ARRAY_SIZE(paramWarnings); i++) {
+static WarningBehavior getWarningBehavior(WarningID id) {
-		uint8_t maxParam = paramWarnings[i].nbLevels;
+	// Check if warnings are globally disabled
+	if (!warnings)
+		return WarningBehavior::DISABLED;
 
-		if (!strcmp(flag, paramWarnings[i].name)) { // Match!
+	// Get the state of this warning flag
-			if (!strcmp(flag, "numeric-string"))
+	WarningState const &flagState = warningStates.flagStates[id];
-				warning(WARNING_OBSOLETE, "Warning flag \"numeric-string\" is deprecated\n");
+	WarningState const &metaState = warningStates.metaStates[id];
 
-			// If making the warning an error but param is 0, set to the maximum
+	// If subsequent checks determine that the warning flag is enabled, this checks whether it has
-			// This accommodates `-Werror=flag`, but also `-Werror=flag=0`, which is
+	// -Werror without -Wno-error=<flag> or -Wno-error=<meta>, which makes it into an error
-			// thus filtered out by the caller.
+	bool warningIsError = warningsAreErrors && flagState.error != WARNING_DISABLED
-			// A param of 0 makes sense for disabling everything, but neither for
+	                      && metaState.error != WARNING_DISABLED;
-			// enabling nor "erroring". Use the default for those.
+	WarningBehavior enabledBehavior =
-			if (param == 0 && state != WARNING_DISABLED) {
+	    warningIsError ? WarningBehavior::ERROR : WarningBehavior::ENABLED;
-				param = paramWarnings[i].defaultLevel;
-			} else if (param > maxParam) {
-				if (param != 255) // Don't  warn if already capped
-					warnx(
-					    "Got parameter %" PRIu8
-					    " for warning flag \"%s\", but the maximum is %" PRIu8 "; capping.\n",
-					    param,
-					    flag,
-					    maxParam
-					);
-				param = maxParam;
-			}
 
-			// Set the first <param> to enabled/error, and disable the rest
+	// First, check the state of the specific warning flag
-			for (uint8_t ofs = 0; ofs < maxParam; ofs++) {
+	if (flagState.state == WARNING_DISABLED) // -Wno-<flag>
-				warningStates[baseID + ofs] = ofs < param ? state : WARNING_DISABLED;
+		return WarningBehavior::DISABLED;
-			}
+	if (flagState.error == WARNING_ENABLED) // -Werror=<flag>
-			return true;
+		return WarningBehavior::ERROR;
-		}
+	if (flagState.state == WARNING_ENABLED) // -W<flag>
+		return enabledBehavior;
 
-		baseID = (WarningID)(baseID + maxParam);
+	// If no flag is specified, check the state of the "meta" flags that affect this warning flag
-	}
+	if (metaState.state == WARNING_DISABLED) // -Wno-<meta>
-	return false;
+		return WarningBehavior::DISABLED;
+	if (metaState.error == WARNING_ENABLED) // -Werror=<meta>
+		return WarningBehavior::ERROR;
+	if (metaState.state == WARNING_ENABLED) // -W<meta>
+		return enabledBehavior;
+
+	// If no meta flag is specified, check the default state of this warning flag
+	if (warningFlags[id].level == LEVEL_DEFAULT) // enabled by default
+		return enabledBehavior;
+
+	// No flag enables this warning, explicitly or implicitly
+	return WarningBehavior::DISABLED;
 }
 
-enum MetaWarningCommand { META_WARNING_DONE = NB_WARNINGS };
+void WarningState::update(WarningState other) {
-
+	if (other.state != WARNING_DEFAULT)
-// Warnings that probably indicate an error
+		state = other.state;
-static uint8_t const _wallCommands[] = {
+	if (other.error != WARNING_DEFAULT)
-    WARNING_BACKWARDS_FOR,
+		error = other.error;
-    WARNING_BUILTIN_ARG,
+}
-    WARNING_CHARMAP_REDEF,
-    WARNING_EMPTY_DATA_DIRECTIVE,
-    WARNING_EMPTY_STRRPL,
-    WARNING_LARGE_CONSTANT,
-    WARNING_NESTED_COMMENT,
-    WARNING_OBSOLETE,
-    WARNING_PURGE_1,
-    WARNING_PURGE_2,
-    WARNING_UNMAPPED_CHAR_1,
-    META_WARNING_DONE,
-};
-
-// Warnings that are less likely to indicate an error
-static uint8_t const _wextraCommands[] = {
-    WARNING_EMPTY_MACRO_ARG,
-    WARNING_MACRO_SHIFT,
-    WARNING_NESTED_COMMENT,
-    WARNING_OBSOLETE,
-    WARNING_PURGE_1,
-    WARNING_PURGE_2,
-    WARNING_TRUNCATION_1,
-    WARNING_TRUNCATION_2,
-    WARNING_UNMAPPED_CHAR_1,
-    WARNING_UNMAPPED_CHAR_2,
-    META_WARNING_DONE,
-};
-
-// Literally everything. Notably useful for testing
-static uint8_t const _weverythingCommands[] = {
-    WARNING_BACKWARDS_FOR,
-    WARNING_BUILTIN_ARG,
-    WARNING_CHARMAP_REDEF,
-    WARNING_DIV,
-    WARNING_EMPTY_DATA_DIRECTIVE,
-    WARNING_EMPTY_MACRO_ARG,
-    WARNING_EMPTY_STRRPL,
-    WARNING_LARGE_CONSTANT,
-    WARNING_MACRO_SHIFT,
-    WARNING_NESTED_COMMENT,
-    WARNING_OBSOLETE,
-    WARNING_PURGE_1,
-    WARNING_PURGE_2,
-    WARNING_SHIFT,
-    WARNING_SHIFT_AMOUNT,
-    WARNING_TRUNCATION_1,
-    WARNING_TRUNCATION_2,
-    WARNING_UNMAPPED_CHAR_1,
-    WARNING_UNMAPPED_CHAR_2,
-    // WARNING_USER,
-    META_WARNING_DONE,
-};
-
-static uint8_t const *metaWarningCommands[NB_META_WARNINGS] = {
-    _wallCommands,
-    _wextraCommands,
-    _weverythingCommands,
-};
 
 void processWarningFlag(char const *flag) {
-	static bool setError = false;
+	std::string rootFlag = flag;
 
-	// First, try to match against a "meta" warning
+	// Check for `-Werror` or `-Wno-error` to return early
-	for (WarningID id : EnumSeq(META_WARNINGS_START, NB_WARNINGS)) {
+	if (rootFlag == "error") {
-		// TODO: improve the matching performance?
+		// `-Werror` promotes warnings to errors
-		if (!strcmp(flag, warningFlags[id])) {
-			// We got a match!
-			if (setError)
-				errx("Cannot make meta warning \"%s\" into an error", flag);
-
-			for (uint8_t const *ptr = metaWarningCommands[id - META_WARNINGS_START];
-			     *ptr != META_WARNING_DONE;
-			     ptr++) {
-				// Warning flag, set without override
-				if (warningStates[*ptr] == WARNING_DEFAULT)
-					warningStates[*ptr] = WARNING_ENABLED;
-			}
-
-			return;
-		}
-	}
-
-	// If it's not a meta warning, specially check against `-Werror`
-	if (!strncmp(flag, "error", QUOTEDSTRLEN("error"))) {
-		char const *errorFlag = flag + QUOTEDSTRLEN("error");
-
-		switch (*errorFlag) {
-		case '\0':
-			// `-Werror`
 		warningsAreErrors = true;
 		return;
-
+	} else if (rootFlag == "no-error") {
-		case '=':
+		// `-Wno-error` disables promotion of warnings to errors
-			// `-Werror=XXX`
+		warningsAreErrors = false;
-			setError = true;
-			processWarningFlag(errorFlag + 1); // Skip the `=`
-			setError = false;
 		return;
-
-			// Otherwise, allow parsing as another flag
-		}
 	}
 
-	// Well, it's either a normal warning or a mistake
+	// Check for prefixes that affect what the flag does
+	WarningState state;
+	if (rootFlag.starts_with("error=")) {
+		// `-Werror=<flag>` enables the flag as an error
+		state = {.state = WARNING_ENABLED, .error = WARNING_ENABLED};
+		rootFlag.erase(0, QUOTEDSTRLEN("error="));
+	} else if (rootFlag.starts_with("no-error=")) {
+		// `-Wno-error=<flag>` prevents the flag from being an error,
+		// without affecting whether it is enabled
+		state = {.state = WARNING_DEFAULT, .error = WARNING_DISABLED};
+		rootFlag.erase(0, QUOTEDSTRLEN("no-error="));
+	} else if (rootFlag.starts_with("no-")) {
+		// `-Wno-<flag>` disables the flag
+		state = {.state = WARNING_DISABLED, .error = WARNING_DEFAULT};
+		rootFlag.erase(0, QUOTEDSTRLEN("no-"));
+	} else {
+		// `-W<flag>` enables the flag
+		state = {.state = WARNING_ENABLED, .error = WARNING_DEFAULT};
+	}
 
-	WarningState state = setError ? WARNING_ERROR
+	// Check for an `=` parameter to process as a parametric warning
-	                     // Not an error, then check if this is a negation
+	// `-Wno-<flag>` and `-Wno-error=<flag>` negation cannot have an `=` parameter, but without a
-	                     : strncmp(flag, "no-", QUOTEDSTRLEN("no-")) ? WARNING_ENABLED
+	// parameter, the 0 value will apply to all levels of a parametric warning
-	                                                                 : WARNING_DISABLED;
+	uint8_t param = 0;
-	char const *rootFlag = state == WARNING_DISABLED ? flag + QUOTEDSTRLEN("no-") : flag;
+	bool hasParam = false;
-
+	if (state.state == WARNING_ENABLED) {
-	// Is this a "parametric" warning?
-	if (state != WARNING_DISABLED) { // The `no-` form cannot be parametrized
 		// First, check if there is an "equals" sign followed by a decimal number
-		char const *equals = strchr(rootFlag, '=');
+		// Ignore an equal sign at the very end of the string
+		if (auto equals = rootFlag.find('=');
+		    equals != rootFlag.npos && equals != rootFlag.size() - 1) {
+			hasParam = true;
 
-		if (equals && equals[1] != '\0') { // Ignore an equal sign at the very end as well
 			// Is the rest of the string a decimal number?
 			// We want to avoid `strtoul`'s whitespace and sign, so we parse manually
-			uint8_t param = 0;
+			char const *ptr = rootFlag.c_str() + equals + 1;
-			char const *ptr = equals + 1;
 			bool warned = false;
 
 			// The `if`'s condition above ensures that this will run at least once
@@ -290,7 +187,7 @@ void processWarningFlag(char const *flag) {
 				// Avoid overflowing!
 				if (param > UINT8_MAX - (*ptr - '0')) {
 					if (!warned)
-						warnx("Invalid warning flag \"%s\": capping parameter at 255\n", flag);
+						warnx("Invalid warning flag \"%s\": capping parameter at 255", flag);
 					warned = true; // Only warn once, cap always
 					param = 255;
 					continue;
@@ -300,40 +197,83 @@ void processWarningFlag(char const *flag) {
 				ptr++;
 			} while (*ptr);
 
-			// If we managed to the end of the string, check that the warning indeed
+			// If we reached the end of the string, truncate it at the '='
-			// accepts a parameter
 			if (*ptr == '\0') {
-				if (setError && param == 0) {
+				rootFlag.resize(equals);
-					warnx("Ignoring nonsensical warning flag \"%s\"\n", flag);
+				// `-W<flag>=0` is equivalent to `-Wno-<flag>`
-					return;
+				if (param == 0)
+					state.state = WARNING_DISABLED;
+			}
+		}
 	}
 
-				std::string truncFlag = rootFlag;
+	// Try to match the flag against a parametric warning
+	// If there was an equals sign, it will have set `param`; if not, `param` will be 0, which
+	// applies to all levels
+	for (auto const &paramWarning : paramWarnings) {
+		WarningID baseID = paramWarning.firstID;
+		uint8_t maxParam = paramWarning.lastID - baseID + 1;
+		assume(paramWarning.defaultLevel <= maxParam);
 
-				truncFlag.resize(equals - rootFlag); // Truncate the param at the '='
+		if (rootFlag == warningFlags[baseID].name) { // Match!
-				if (tryProcessParamWarning(
+			if (rootFlag == "numeric-string")
-				        truncFlag.c_str(), param, param == 0 ? WARNING_DISABLED : state
+				warning(WARNING_OBSOLETE, "Warning flag \"numeric-string\" is deprecated\n");
-				    ))
+
+			// If making the warning an error but param is 0, set to the maximum
+			// This accommodates `-Werror=<flag>`, but also `-Werror=<flag>=0`, which is
+			// thus filtered out by the caller.
+			// A param of 0 makes sense for disabling everything, but neither for
+			// enabling nor "erroring". Use the default for those.
+			if (param == 0) {
+				param = paramWarning.defaultLevel;
+			} else if (param > maxParam) {
+				if (param != 255) // Don't warn if already capped
+					warnx(
+					    "Invalid parameter %" PRIu8
+					    " for warning flag \"%s\"; capping at maximum %" PRIu8,
+					    param,
+					    rootFlag.c_str(),
+					    maxParam
+					);
+				param = maxParam;
+			}
+
+			// Set the first <param> to enabled/error, and disable the rest
+			for (uint8_t ofs = 0; ofs < maxParam; ofs++) {
+				WarningState &warning = warningStates.flagStates[baseID + ofs];
+				if (ofs < param)
+					warning.update(state);
+				else
+					warning.state = WARNING_DISABLED;
+			}
 			return;
 		}
 	}
+
+	// Try to match against a non-parametric warning, unless there was an equals sign
+	if (!hasParam) {
+		// Try to match against a "meta" warning
+		for (WarningFlag const &metaWarning : metaWarnings) {
+			if (rootFlag == metaWarning.name) {
+				// Set each of the warning flags that meets this level
+				for (WarningID id : EnumSeq(NB_WARNINGS)) {
+					if (metaWarning.level >= warningFlags[id].level)
+						warningStates.metaStates[id].update(state);
+				}
+				return;
+			}
 		}
 
 		// Try to match the flag against a "normal" flag
 		for (WarningID id : EnumSeq(NB_PLAIN_WARNINGS)) {
-		if (!strcmp(rootFlag, warningFlags[id])) {
+			if (rootFlag == warningFlags[id].name) {
-			// We got a match!
+				warningStates.flagStates[id].update(state);
-			warningStates[id] = state;
 				return;
 			}
 		}
+	}
 
-	// Lastly, this might be a "parametric" warning without an equals sign
+	warnx("Unknown warning flag \"%s\"", flag);
-	// If it is, treat the param as 1 if enabling, or 0 if disabling
-	if (tryProcessParamWarning(rootFlag, 0, state))
-		return;
-
-	warnx("Unknown warning `%s`", flag);
 }
 
 void printDiag(
@@ -377,26 +317,22 @@ void error(char const *fmt, ...) {
 }
 
 void warning(WarningID id, char const *fmt, ...) {
-	char const *flag = warningFlags[id];
+	char const *flag = warningFlags[id].name;
 	va_list args;
 
 	va_start(args, fmt);
 
-	switch (warningState(id)) {
+	switch (getWarningBehavior(id)) {
-	case WARNING_DISABLED:
+	case WarningBehavior::DISABLED:
 		break;
 
-	case WARNING_ENABLED:
+	case WarningBehavior::ENABLED:
 		printDiag(fmt, args, "warning", ": [-W%s]", flag);
 		break;
 
-	case WARNING_ERROR:
+	case WarningBehavior::ERROR:
 		printDiag(fmt, args, "error", ": [-Werror=%s]", flag);
 		break;
-
-	case WARNING_DEFAULT:
-		unreachable_();
-		// Not reached
 	}
 
 	va_end(args);