handle typedefs of anonymous structures

demofiles/use-after-free.c

@@ -8,11 +8,11 @@ int main() {
     int *ptr = (int *)malloc(sizeof(*ptr));
     assert(ptr != 0);
     *ptr = 42;
-    printf("%p %d\n", ptr, *ptr);
+    printf("%d\n", *ptr);
     free(ptr);
-    printf("%p %d\n", ptr, *ptr);	// use after free
-    // the following usully causes a SEGV in the interpreter because the store corrupts GC memory
-    *ptr = 43;				// use after free
-    printf("%p %d\n", ptr, *ptr);	// use after free
+    printf("%d\n", *ptr);	// use after free
+    // the following sometimes causes a SEGV in the interpreter because the store corrupts GC memory
+    *ptr = 43;			// use after free
+    printf("%d\n", *ptr);	// use after free
     return 0;
 }

main.leg

@@ -1,6 +1,6 @@
 # main.leg -- C parser + interpreter
 #
-# Last edited: 2025-02-01 10:24:25 by piumarta on xubuntu
+# Last edited: 2025-02-01 15:04:48 by piumarta on xubuntu
 
 %{
 ;
@@ -755,17 +755,19 @@ oop tags = 0;
 
 oop newTstruct(oop tag, oop members)
 {
-    List_do(tags, t) {
-	if (tag == get(t, Tstruct,tag)) {
-	    if (!is(Tstruct, t))
-		fatal("tag '%s' redeclared as different type", symbolName(tag));
-	    oop oldmembers = get(t, Tstruct,members);
-	    if (!isNil(oldmembers) && !isNil(members)) {
-		fatal("tag '%s' redefined", symbolName(tag));
+    if (!isNil(tag)) {
+	List_do(tags, t) {
+	    if (tag == get(t, Tstruct,tag)) {
+		if (!is(Tstruct, t))
+		    fatal("tag '%s' redeclared as different type", symbolName(tag));
+		oop oldmembers = get(t, Tstruct,members);
+		if (!isNil(oldmembers) && !isNil(members)) {
+		    fatal("tag '%s' redefined", symbolName(tag));
+		}
+		if (isNil(oldmembers) && !isNil(members))
+		    set(t, Tstruct,members, members);
+		return t; // uniqe types allow comparison by identity
 	    }
-	    if (isNil(oldmembers) && !isNil(members))
-		set(t, Tstruct,members, members);
-	    return t; // uniqe types allow comparison by identity
 	}
     }
     oop obj = new(Tstruct);
@@ -1802,6 +1804,7 @@ stmt	= WHILE c:cond s:stmt	 	{ $$ = newWhile(c, s) }
 	| BREAK  SEMI			{ $$ = newBreak() }
 	| block
 	| e:expr SEMI			{ $$ = e }
+	| typedec
 	| vardecl
 
 cond	= LPAREN e:expr RPAREN		{ $$ = e }
@@ -3198,7 +3201,7 @@ oop assign(oop lhs, oop rhs)
 	    }
 	    break;
 	}
-	case Member: {
+	case Member: { // soru.name = rhs
 	    oop name 	= get(lhs, Member,name);
 	    oop soru 	= eval(get(lhs, Member,lhs)); // struct or union
 	    oop type    = nil;
@@ -3231,7 +3234,7 @@ oop assign(oop lhs, oop rhs)
 	    assert(offset + vsize <= size);
 	    return setMemory(memory, offset, vtype, eval(rhs));
 	}
-	case Dereference: { // *<&var> = rhs
+	case Dereference: { // *<&var> = rhs, *<&const> = rhs, *<&memory> = rhs
 	    lhs = eval(get(lhs, Dereference,rhs));
 	    switch (getType(lhs)) {
 		case Pointer: { // &x
@@ -3848,13 +3851,7 @@ oop eval(oop exp)
 	    }
 	    RETURN(nil);
 	}
-	case TypeDecls: {
-	    oop types = get(exp, TypeDecls,typenames);
-	    List_do(types, type) {
-		oop name = get(type, TypeName,name);
-		oop type = get(type, TypeName,type);
-		declareType(name, type);
-	    }
+	case TypeDecls: { // local typenames only used within typeCheck() and can be ignored here
 	    RETURN(nil);
 	}
 	case Scope:	break;

test.txt

@@ -24,6 +24,10 @@ int gbl[5];
 
 int gg[] = { -2, ~2, !2, 6+7, 6*7 };
 
+struct         G1 { int x, y; };
+typedef struct G2 { int x, y; } G2_t;
+typedef struct    { int x, y; } G3_t;
+
 int main(int argc, char **argv)
 {
     printf("hello, world %d %s\n", foo(), bar());
@@ -106,6 +110,36 @@ int main(int argc, char **argv)
     for (i = 0;  i < sizeof gg / sizeof(int);  ++i) printf("g %d ", gg[i]);    printf("\n");
     for (i = 0;  i < sizeof ll / sizeof(int);  ++i) printf("l %d ", ll[i]);    printf("\n");
 
+    struct S { int a, b; };
+
+    typedef struct S SS;
+
+    SS s;
+
+    s.a = 42;
+    s.b = 666;
+    printf("%d %d\n", s.a, s.b);
+
+    struct         L1 { int x, y; };
+    typedef struct L2 { int x, y; } L2_t;
+    typedef struct    { int x, y; } L3_t;
+
+    struct G1 g1 = { 10, 11 };
+    G2_t      g2 = { 12, 13 };
+    G3_t      g3 = { 14, 15 };
+
+    struct L1 l1 = { 20, 21 };
+    L2_t      l2 = { 22, 23 };
+    L3_t      l3 = { 24, 25 };
+
+    printf("%d %d %d %d %d %d %d %d %d %d %d %d\n", g1.x, g1.y, g2.x, g2.y, g3.x, g3.y, l1.x, l1.y, l2.x, l2.y, l3.x, l3.y);
+
+    typedef L2_t L2_t_t;
+
+    L2_t_t ll2 = { 42, 666 };
+
+    printf("%d %d\n", ll2.x, ll2.y);
+
     printf("passed\n");
 
     return 0;