implement enough type analysis for vector examplegnc

+ Big commit, scary
+ Some details still a bit up in the air, mainly about move checking
  structure member access ('register' types are freely copied I guess,
  same as in rust? How about user types?)

1 files changed, 96 insertions, 0 deletions

diff --git a/src/rewrite.c b/src/rewrite.c
new file mode 100644
index 0000000..e3cea01
--- /dev/null
+++ b/src/rewrite.c
@@ -0,0 +1,96 @@
+#include <fwd/rewrite.h>
+#include <stddef.h>
+#include <stdlib.h>
+
+struct type_helper {
+	char *orig;
+	char *new;
+};
+
+/* types are simple enough (for now) that this works fine */
+static int rewrite_type_ids(struct type *type, char *orig, char *new)
+{
+	if (type->k == TYPE_ID && strcmp(type->id, orig) == 0) {
+		char *r = strdup(new);
+		free(type->id);
+		type->id = r;
+	}
+
+	if (type->t0 && rewrite_type_ids(type->t0, orig, new))
+		return -1;
+
+	if (type->n && rewrite_type_ids(type->n, orig, new))
+		return -1;
+
+	return 0;
+}
+
+static int rewrite_type_visit(struct ast *node, struct type_helper *helper)
+{
+	if (node->t2)
+		return rewrite_type_ids(node->t2, helper->orig, helper->new);
+
+	return 0;
+}
+
+int rewrite_types(struct ast *node, char *orig, char *new)
+{
+	struct type_helper helper = {.orig = orig, .new = new};
+	return ast_visit((ast_callback_t)rewrite_type_visit, NULL, node, &helper);
+}
+
+/* not the fastest thing in the world but should work well enough for now */
+static char *rewrite_hole(char *old, char *new)
+{
+	/* skip "<>" */
+	size_t on = strlen(old) - 2;
+	size_t nn = strlen(new);
+
+	/* +1 for null terminator */
+	char *r = malloc(on + nn + 1);
+
+	memcpy(r, new, nn);
+
+	/* +2 to skip "<>", +1 for null terminator */
+	memcpy(r + nn, old + 2, on + 1);
+	return r;
+}
+
+static int rewrite_type_holes(struct type *type, char *new)
+{
+	if (type->id && strncmp(type->id, "<>", 2) == 0) {
+		char *r = rewrite_hole(type->id, new);
+		free(type->id);
+		type->id = r;
+	}
+
+	if (type->t0 && rewrite_type_holes(type->t0, new))
+		return -1;
+
+	if (type->n && rewrite_type_holes(type->n, new))
+		return -1;
+
+	return 0;
+}
+
+static int rewrite_holes_visit(struct ast *node, char *new)
+{
+	if (node->k == AST_CONST_STR)
+		return 0;
+
+	if (node->s && strncmp(node->s, "<>", 2) == 0) {
+		char *r = rewrite_hole(node->s, new);
+		free(node->s);
+		node->s = r;
+	}
+
+	if (node->t2 && rewrite_type_holes(node->t2, new))
+		return -1;
+
+	return 0;
+}
+
+int rewrite_holes(struct ast *node, char *new)
+{
+	return ast_visit((ast_callback_t)rewrite_holes_visit, NULL, node, new);
+}