Move kind-specific decl fields to union

5 files changed, 53 insertions, 45 deletions

diff --git a/cc.h b/cc.h
index 263b209..6f2a193 100644
--- a/cc.h
+++ b/cc.h
@@ -271,15 +271,19 @@ struct decl {
 	char *asmname;
 	_Bool defined;
 
-	/* link in list of tentative object definitions */
-	struct list tentative;
-	/* alignment of object storage (may be stricter than type requires) */
-	int align;
-
-	/* the function might have an "inline definition" (C11 6.7.4p7) */
-	_Bool inlinedefn;
-
-	enum builtinkind builtin;
+	union {
+		struct {
+			/* link in list of tentative object definitions */
+			struct list tentative;
+			/* alignment of object storage (may be stricter than type requires) */
+			int align;
+		} obj;
+		struct {
+			/* the function might have an "inline definition" (C11 6.7.4p7) */
+			_Bool inlinedefn;
+		} func;
+		enum builtinkind builtin;
+	} u;
 };
 
 struct scope {
diff --git a/decl.c b/decl.c
index 809cf25..4a0d319 100644
--- a/decl.c
+++ b/decl.c
@@ -947,8 +947,8 @@ decl(struct scope *s, struct func *f)
 			d = declcommon(s, kind, name, asmname, t, tq, sc, prior);
 			if (align && align < t->align)
 				error(&tok.loc, "specified alignment of object '%s' is less strict than is required by type", name);
-			if (d->align < align)
-				d->align = align;
+			if (d->u.obj.align < align)
+				d->u.obj.align = align;
 			init = NULL;
 			if (consume(TASSIGN)) {
 				if (f && d->linkage != LINKNONE)
@@ -957,8 +957,8 @@ decl(struct scope *s, struct func *f)
 					error(&tok.loc, "object '%s' redefined", name);
 				init = parseinit(s, d->type);
 			} else if (d->linkage != LINKNONE) {
-				if (!(sc & SCEXTERN) && !d->defined && !d->tentative.next)
-					listinsert(tentativedefns.prev, &d->tentative);
+				if (!(sc & SCEXTERN) && !d->defined && !d->u.obj.tentative.next)
+					listinsert(tentativedefns.prev, &d->u.obj.tentative);
 				break;
 			}
 			if (d->linkage != LINKNONE || sc & SCSTATIC)
@@ -966,8 +966,8 @@ decl(struct scope *s, struct func *f)
 			else
 				funcinit(f, d, init);
 			d->defined = true;
-			if (d->tentative.next)
-				listremove(&d->tentative);
+			if (d->u.obj.tentative.next)
+				listremove(&d->u.obj.tentative);
 			break;
 		case DECLFUNC:
 			if (align)
@@ -989,7 +989,7 @@ decl(struct scope *s, struct func *f)
 				}
 			}
 			d = declcommon(s, kind, name, asmname, t, tq, sc, prior);
-			d->inlinedefn = d->linkage == LINKEXTERN && fs & FUNCINLINE && !(sc & SCEXTERN) && (!prior || prior->inlinedefn);
+			d->u.func.inlinedefn = d->linkage == LINKEXTERN && fs & FUNCINLINE && !(sc & SCEXTERN) && (!prior || prior->u.func.inlinedefn);
 			if (tok.kind == TLBRACE) {
 				if (!allowfunc)
 					error(&tok.loc, "function definition not allowed");
@@ -999,7 +999,7 @@ decl(struct scope *s, struct func *f)
 				f = mkfunc(d, name, t, s);
 				stmt(f, s);
 				/* XXX: need to keep track of function in case a later declaration specifies extern */
-				if (!d->inlinedefn)
+				if (!d->u.func.inlinedefn)
 					emitfunc(f, d->linkage == LINKEXTERN);
 				s = delscope(s);
 				delfunc(f);
@@ -1044,5 +1044,5 @@ emittentativedefns(void)
 	struct list *l;
 
 	for (l = tentativedefns.next; l != &tentativedefns; l = l->next)
-		emitdata(listelement(l, struct decl, tentative), NULL);
+		emitdata(listelement(l, struct decl, u.obj.tentative), NULL);
 }
diff --git a/expr.c b/expr.c
index 955b73f..1fe280c 100644
--- a/expr.c
+++ b/expr.c
@@ -906,7 +906,7 @@ postfixexpr(struct scope *s, struct expr *r)
 		case TLPAREN:  /* function call */
 			next();
 			if (r->kind == EXPRIDENT && r->u.ident.decl->kind == DECLBUILTIN) {
-				e = builtinfunc(s, r->u.ident.decl->builtin);
+				e = builtinfunc(s, r->u.ident.decl->u.builtin);
 				expect(TRPAREN, "after builtin parameters");
 				break;
 			}
diff --git a/qbe.c b/qbe.c
index 3bcd0ae..04cce00 100644
--- a/qbe.c
+++ b/qbe.c
@@ -256,29 +256,31 @@ funcalloc(struct func *f, struct decl *d)
 	enum instkind op;
 	struct inst *inst;
 	unsigned long long size;
+	int align;
 
 	assert(!d->type->incomplete);
 	assert(d->type->size > 0);
-	if (!d->align)
-		d->align = d->type->align;
-	else if (d->align < d->type->align)
-		error(&tok.loc, "object requires alignment %d, which is stricter than %d", d->type->align, d->align);
+	align = d->u.obj.align;
+	if (!align)
+		align = d->type->align;
+	else if (align < d->type->align)
+		error(&tok.loc, "object requires alignment %d, which is stricter than %d", d->type->align, align);
 	size = d->type->size;
-	switch (d->align) {
+	switch (align) {
 	case 1:
 	case 2:
 	case 4:  op = IALLOC4; break;
 	case 8:  op = IALLOC8; break;
-	default: size += d->align - 16; /* fallthrough */
+	default: size += align - 16; /* fallthrough */
 	case 16: op = IALLOC16; break;
 	}
 	inst = mkinst(f, op, ptrclass, mkintconst(size), NULL);
 	arrayaddptr(&f->start->insts, inst);
-	if (d->align > 16) {
+	if (align > 16) {
 		/* TODO: implement alloc32 in QBE and use that instead */
-		inst = mkinst(f, IADD, ptrclass, &inst->res, mkintconst(d->align - 16));
+		inst = mkinst(f, IADD, ptrclass, &inst->res, mkintconst(align - 16));
 		arrayaddptr(&f->start->insts, inst);
-		inst = mkinst(f, IAND, ptrclass, &inst->res, mkintconst(-d->align));
+		inst = mkinst(f, IAND, ptrclass, &inst->res, mkintconst(-align));
 		arrayaddptr(&f->start->insts, inst);
 	}
 	d->value = &inst->res;
@@ -1321,18 +1323,20 @@ emitdata(struct decl *d, struct init *init)
 	struct type *t;
 	unsigned long long offset = 0, start, end, bits = 0;
 	size_t i;
+	int align;
 
-	if (!d->align)
-		d->align = d->type->align;
-	else if (d->align < d->type->align)
-		error(&tok.loc, "object requires alignment %d, which is stricter than %d", d->type->align, d->align);
+	align = d->u.obj.align;
+	if (!align)
+		align = d->type->align;
+	else if (align < d->type->align)
+		error(&tok.loc, "object requires alignment %d, which is stricter than %d", d->type->align, align);
 	for (cur = init; cur; cur = cur->next)
 		cur->expr = eval(cur->expr, EVALINIT);
 	if (d->linkage == LINKEXTERN)
 		fputs("export ", stdout);
 	fputs("data ", stdout);
 	emitvalue(d->value);
-	printf(" = align %d { ", d->align);
+	printf(" = align %d { ", align);
 
 	while (init) {
 		cur = init;
diff --git a/scope.c b/scope.c
index 299d379..ab6e293 100644
--- a/scope.c
+++ b/scope.c
@@ -14,19 +14,19 @@ scopeinit(void)
 		char *name;
 		struct decl decl;
 	} builtins[] = {
-		{"__builtin_alloca",     {.kind = DECLBUILTIN, .builtin = BUILTINALLOCA}},
-		{"__builtin_constant_p", {.kind = DECLBUILTIN, .builtin = BUILTINCONSTANTP}},
-		{"__builtin_expect",     {.kind = DECLBUILTIN, .builtin = BUILTINEXPECT}},
-		{"__builtin_inff",       {.kind = DECLBUILTIN, .builtin = BUILTININFF}},
-		{"__builtin_nanf",       {.kind = DECLBUILTIN, .builtin = BUILTINNANF}},
-		{"__builtin_offsetof",   {.kind = DECLBUILTIN, .builtin = BUILTINOFFSETOF}},
+		{"__builtin_alloca",     {.kind = DECLBUILTIN, .u.builtin = BUILTINALLOCA}},
+		{"__builtin_constant_p", {.kind = DECLBUILTIN, .u.builtin = BUILTINCONSTANTP}},
+		{"__builtin_expect",     {.kind = DECLBUILTIN, .u.builtin = BUILTINEXPECT}},
+		{"__builtin_inff",       {.kind = DECLBUILTIN, .u.builtin = BUILTININFF}},
+		{"__builtin_nanf",       {.kind = DECLBUILTIN, .u.builtin = BUILTINNANF}},
+		{"__builtin_offsetof",   {.kind = DECLBUILTIN, .u.builtin = BUILTINOFFSETOF}},
 		{"__builtin_types_compatible_p",
-			{.kind = DECLBUILTIN, .builtin = BUILTINTYPESCOMPATIBLEP}},
-		{"__builtin_unreachable", {.kind = DECLBUILTIN, .builtin = BUILTINUNREACHABLE}},
-		{"__builtin_va_arg",     {.kind = DECLBUILTIN, .builtin = BUILTINVAARG}},
-		{"__builtin_va_copy",    {.kind = DECLBUILTIN, .builtin = BUILTINVACOPY}},
-		{"__builtin_va_end",     {.kind = DECLBUILTIN, .builtin = BUILTINVAEND}},
-		{"__builtin_va_start",   {.kind = DECLBUILTIN, .builtin = BUILTINVASTART}},
+			{.kind = DECLBUILTIN, .u.builtin = BUILTINTYPESCOMPATIBLEP}},
+		{"__builtin_unreachable", {.kind = DECLBUILTIN, .u.builtin = BUILTINUNREACHABLE}},
+		{"__builtin_va_arg",     {.kind = DECLBUILTIN, .u.builtin = BUILTINVAARG}},
+		{"__builtin_va_copy",    {.kind = DECLBUILTIN, .u.builtin = BUILTINVACOPY}},
+		{"__builtin_va_end",     {.kind = DECLBUILTIN, .u.builtin = BUILTINVAEND}},
+		{"__builtin_va_start",   {.kind = DECLBUILTIN, .u.builtin = BUILTINVASTART}},
 	};
 	static struct decl valist;
 	struct builtin *b;