Add support for K&R-style anonymous structures and unions

4 files changed, 100 insertions, 3 deletions

diff --git a/bcc/declare.c b/bcc/declare.c
index 0820c4b..a92c545 100644
--- a/bcc/declare.c
+++ b/bcc/declare.c
@@ -2,6 +2,9 @@
 
 /* Copyright (C) 1992 Bruce Evans */
 
+#ifndef VERY_SMALL_MEMORY
+#include <stdio.h>
+#endif
 #include "bcc.h"
 #include "align.h"
 #include "byteord.h"
@@ -26,6 +29,10 @@ PRIVATE char gvar2name[2 + NAMESIZE];	/* space for structure keys and .. */
 PRIVATE struct typestruct *gvartype;	/* type of last identifier declared */
 PRIVATE bool_t initlistflag;	/* remembers whether initializer is a list */
 
+#ifndef VERY_SMALL_MEMORY
+PRIVATE int anons = 0;		/* number of anonymous structures/unions seen */
+#endif
+
 FORWARD struct typestruct *chainprefix P((struct typestruct *pretype,
 					   struct typestruct *sufftype));
 FORWARD void declaf P((void));
@@ -219,7 +226,12 @@ PRIVATE void declarator()
 {
     rdeclarator();
     if (gvartype->constructor == STRUCTU && gvartype->typesize == 0 &&
+/* We don't do the anonymous union/structure trickery on low mem machines */
+#ifdef VERY_SMALL_MEMORY
 	gvarsc != TYPEDEFDECL && gvarsc != EXTERNDECL)
+#else
+	gvarsc != TYPEDEFDECL && gvarsc != EXTERNDECL && gvarsc != NULLDECL)
+#endif
 	error("undefined structure");
 }
 
@@ -328,10 +340,21 @@ struct typelist **ptypelist;
     if (gvarsc != NULLDECL)
 	error("illegal type name");
     basetype = gvartype;
+
+#ifndef VERY_SMALL_MEMORY
+    if (sym == SEMICOLON || sym == EOFSYM) {
+	/* Generate a fake structure if none specified... */
+	anonstruct ();
+	/* ....and pretend it was regularly present in source */
+	goto anonstr;
+    }
+#endif
+
     while (sym != SEMICOLON && sym != EOFSYM)
     {
 	gvartype = basetype;
 	declarator();
+anonstr:
 	fieldwidth = -1;
 	if (sym == COLON)
 	{
@@ -1189,3 +1212,24 @@ PUBLIC struct typestruct *typename()
     gvartype = ogvartype;
     return type;
 }
+
+#ifndef VERY_SMALL_MEMORY
+PUBLIC int lastanon()
+{
+    return anons;
+}
+
+PUBLIC void anonname(name, i)
+char *name;
+int i;
+{
+    if (i == 0xfff)
+        fatalerror("Too many anonymous structs/unions");
+    sprintf (name, "__an%03x", i);
+}
+
+PUBLIC void anonstruct()
+{
+    anonname (gvarname, anons++);
+}
+#endif
diff --git a/bcc/express.c b/bcc/express.c
index 9533d91..f57db0a 100644
--- a/bcc/express.c
+++ b/bcc/express.c
@@ -285,9 +285,16 @@ bool_pt seenlp;
 	    nodeptr = node(INDIRECTOP, nodeptr, NULLNODE);
 	case STRUCELTOP:
 	    nextsym();
-	    gs2name[0] = nodeptr->nodetype->structkey[0];
-	    gs2name[1] = nodeptr->nodetype->structkey[1];
-	    if ((gsymptr = findlorg(gs2name)) == NULL)
+/* On memory constrained systems we save space that would be needed to keep */
+/* track of anonymous structure members by not implementing lookup in them */
+/* at all. */
+#ifdef VERY_SMALL_MEMORY
+            gs2name[0] = nodeptr->nodetype->structkey[0];
+            gs2name[1] = nodeptr->nodetype->structkey[1];
+            if ((gsymptr = findlorg(gs2name)) == NULL)
+#else
+	    if ((gsymptr = findstrm(nodeptr->nodetype, gs2name)) == NULL)
+#endif
 	    {
 		error("undefined structure element");
 		gsymptr = addglb(gs2name, itype);
diff --git a/bcc/proto.h b/bcc/proto.h
index 3b44a56..baee0c3 100644
--- a/bcc/proto.h
+++ b/bcc/proto.h
@@ -119,6 +119,11 @@ void rbracket P((void));
 void rparen P((void));
 void semicolon P((void));
 struct typestruct *typename P((void));
+#ifndef VERY_SMALL_MEMORY
+int lastanon P((void));
+void anonname P((char *name, int i));
+void anonstruct P((void));
+#endif
 
 /* express.c */
 struct nodestruct *assignment_exp P((void));
@@ -355,6 +360,9 @@ void outofmemoryerror P((char *message));
 void *qmalloc P((unsigned size));
 void swapsym P((struct symstruct *sym1, struct symstruct *sym2));
 void syminit P((void));
+#ifndef VERY_SMALL_MEMORY
+struct symstruct *findstrm P((struct typestruct *type, char *name));
+#endif
 
 /* type.c */
 struct typestruct *addstruct P((char *structname));
diff --git a/bcc/table.c b/bcc/table.c
index 166c143..e863fb5 100644
--- a/bcc/table.c
+++ b/bcc/table.c
@@ -691,3 +691,41 @@ PUBLIC void syminit()
 	addkeyword(kwptr->kwname, kwptr->kwcode);
     constemplate.type = itype;
 }
+
+#ifndef VERY_SMALL_MEMORY
+PUBLIC struct symstruct *findstrm(type, name)
+struct typestruct *type;
+char *name;
+{
+    struct symstruct *symptr;
+    int i;
+    char anon[2 + NAMESIZE];
+    struct typelist *tl;
+
+    /* Look for a struct member named as given */
+    name[0] = type->structkey[0];
+    name[1] = type->structkey[1];
+	if ((symptr = findlorg(name)) != NULL)
+	    return symptr;
+
+    /* No match? Fine, let's see if there are any anynymous structures
+     * or unions that we could recurse into */
+    for (i = 0; i < lastanon(); i++)
+    {
+	anon[0] = type->structkey[0];
+	anon[1] = type->structkey[1];
+	anonname(&anon[2], i);
+	if ((symptr = findlorg(anon)) != NULL)
+	{
+	    /* Found an anonymous struture */
+	    if (!(symptr->type->constructor & STRUCTU))
+		error("Anonymous structure not a structure?!");
+	    /* Look for the member */
+	    strcpy(&anon[2], &name[2]);
+	    if ((symptr = findstrm(symptr->type, anon)) != NULL)
+		return symptr;
+	}
+    }
+    return NULL;
+}
+#endif