[qfcc] Implement anonymous structs and unions

For struct/union scope

tools/qfcc/include/symtab.h

@@ -45,6 +45,7 @@ typedef enum vis_e {
 	vis_public,
 	vis_protected,
 	vis_private,
+	vis_anonymous,
 } vis_t;
 
 typedef enum {

tools/qfcc/source/qc-parse.y

@@ -42,6 +42,7 @@
 
 #include <QF/hash.h>
 #include <QF/sys.h>
+#include <QF/va.h>
 
 #include "class.h"
 #include "debug.h"
@@ -264,6 +265,26 @@ default_type (specifier_t spec, symbol_t *sym)
 	return spec;
 }
 
+static int
+is_anonymous_struct (specifier_t spec)
+{
+	if (spec.sym) {
+		return 0;
+	}
+	if (!is_struct (spec.type)) {
+		return 0;
+	}
+	if (spec.type->t.symtab->parent) {
+		return 0;
+	}
+	// struct and union type names always begin with "tag ". Untagged s/u
+	// are "tag .<filename>.<id>".
+	if (spec.type->name[4] != '.') {
+		return 0;
+	}
+	return 1;
+}
+
 %}
 
 %expect 0
@@ -675,15 +696,27 @@ struct_def
 	: type struct_decl_list
 	| type
 		{
-			if ($1.sym) {
+			if ($1.sym && $1.sym->type != $1.type) {
 				// a type name (id, typedef, etc) was used as a field name.
 				// this is allowed in C
-				print_type ($1.type);
-				printf ("%s\n", $1.sym->name);
 				$1.sym = new_symbol ($1.sym->name);
 				$1.sym->type = $1.type;
 				$1.sym->sy_type = sy_var;
 				symtab_addsymbol (current_symtab, $1.sym);
+				if (!$1.sym->table) {
+					error (0, "duplicate field `%s'", $1.sym->name);
+				}
+			} else if (is_anonymous_struct ($1)) {
+				// anonymous struct/union
+				// type->name always begins with "tag "
+				$1.sym = new_symbol (va (".anonymous.%s", $1.type->name + 4));
+				$1.sym->type = $1.type;
+				$1.sym->sy_type = sy_var;
+				$1.sym->visibility = vis_anonymous;
+				symtab_addsymbol (current_symtab, $1.sym);
+				if (!$1.sym->table) {
+					error (0, "duplicate field `%s'", $1.sym->name);
+				}
 			} else {
 				// bare type
 				warning (0, "declaration does not declare anything");

tools/qfcc/source/struct.c

@@ -114,6 +114,7 @@ build_struct (int su, symbol_t *tag, symtab_t *symtab, type_t *type)
 	symbol_t   *sym = find_struct (su, tag, type);
 	symbol_t   *s;
 	int         alignment = 1;
+	symbol_t   *as;
 
 	symtab->parent = 0;		// disconnect struct's symtab from parent scope
 
@@ -140,6 +141,28 @@ build_struct (int su, symbol_t *tag, symtab_t *symtab, type_t *type)
 		if (s->type->alignment > alignment) {
 			alignment = s->type->alignment;
 		}
+		if (s->visibility == vis_anonymous) {
+			symtab_t   *anonymous;
+			symbol_t   *t = s->next;
+			int         offset = s->s.offset;
+
+			if (!is_struct (s->type)) {
+				internal_error (0, "non-struct/union anonymous field");
+			}
+			anonymous = s->type->t.symtab;
+			for (as = anonymous->symbols; as; as = as->next) {
+				if (Hash_Find (symtab->tab, as->name)) {
+					error (0, "ambiguous field `%s' in anonymous %s",
+						   as->name, su == 's' ? "struct" : "union");
+				} else {
+					s->next = copy_symbol (as);
+					s = s->next;
+					s->s.offset += offset;
+					Hash_Add (symtab->tab, s);
+				}
+			}
+			s->next = t;
+		}
 	}
 	if (!type)
 		sym->type = find_type (sym->type);	// checks the tag, not the symtab

tools/qfcc/source/symtab.c

@@ -152,7 +152,7 @@ symtab_removesymbol (symtab_t *symtab, symbol_t *symbol)
 	for (s = &symtab->symbols; *s && *s != symbol; s = & (*s)->next)
 		;
 	if (!*s)
-		internal_error (0, "symtab_removesymbol");
+		internal_error (0, "attempt to remove symbol not in symtab");
 	*s = (*s)->next;
 	if (symtab->symtail == &symbol->next)
 		symtab->symtail = s;

tools/qfcc/test/Makefile.am

@@ -31,6 +31,7 @@ fail_bins=
 test_progs_dat=\
 	address-cast.dat \
 	alignment.dat \
+	anonstruct.dat \
 	chewed-alias.dat \
 	chewed-return.dat \
 	comma-expr.dat \
@@ -119,6 +120,15 @@ alignment.run: Makefile build-run
 include ./$(DEPDIR)/alignment.Qo # am--include-marker
 r_depfiles_remade += ./$(DEPDIR)/alignment.Qo
 
+anonstruct_dat_SOURCES=anonstruct.r
+anonstruct_obj=$(anonstruct_dat_SOURCES:.r=.qfo)
+anonstruct.dat$(EXEEXT): $(anonstruct_obj) $(QFCC_DEP)
+	$(QFCC) $(QCFLAGS) -o $@ $(anonstruct_obj)
+anonstruct.run: Makefile build-run
+	@$(srcdir)/build-run $@
+include ./$(DEPDIR)/anonstruct.Qo # am--include-marker
+r_depfiles_remade += ./$(DEPDIR)/anonstruct.Qo
+
 chewed_alias_dat_SOURCES=chewed-alias.r
 chewed_alias_obj=$(chewed_alias_dat_SOURCES:.r=.qfo)
 chewed-alias.dat$(EXEEXT): $(chewed_alias_obj) $(QFCC_DEP)

tools/qfcc/test/anonstruct.r

@@ -0,0 +1,57 @@
+void printf (string fmt, ...) = #0;
+
+typedef struct xyzzy_s {
+    int         magic;
+} xyzzy_t;
+
+typedef struct anon_s {
+	int         foo;
+	int         id;
+	struct {
+		int         bar;
+		int         baz;
+	};
+	union {
+		int         snafu;
+		float       fizzle;
+	};
+} anon_t;
+
+union {
+	int         xsnafu;
+	float       xfizzle;
+};
+
+int foo (float f)
+{
+	anon_t anon;
+	anon.fizzle = f;
+	return anon.snafu;
+}
+
+int main()
+{
+	anon_t anon;
+	int         ret = 0;
+	if (&anon.snafu != &anon.fizzle) {
+		printf ("anon union broken: %p %p\n",
+				&anon.snafu, &anon.fizzle);
+		ret |= 1;
+	}
+	if (&anon.snafu - &anon.baz != 1) {
+		printf ("snafu and baz not adjacant: snafu:%p baz:%p\n",
+				&anon.snafu, &anon.baz);
+		ret |= 1;
+	}
+	if (&anon.baz - &anon.bar != 1) {
+		printf ("baz and bar not adjacant: baz:%p bar:%p\n",
+				&anon.baz, &anon.bar);
+		ret |= 1;
+	}
+	if (&anon.bar - &anon.id != 1) {
+		printf ("bar not after id: bar:%p id:%p\n",
+				&anon.bar, &anon.id);
+		ret |= 1;
+	}
+	return ret;
+}