From 7a5539455e07826c0d21c01602a40d0abc09741c Mon Sep 17 00:00:00 2001
From: Mart Lubbers <mart@martlubbers.net>
Date: Thu, 11 Feb 2021 14:47:07 +0100
Subject: [PATCH] constant globals checking

---
 ast.c   |  1 +
 parse.y |  1 +
 scc.c   | 11 +++--------
 scc.h   |  3 +--
 type.c  | 39 +++++++++++++++++++++++++++++++++++++--
 5 files changed, 43 insertions(+), 12 deletions(-)

diff --git a/ast.c b/ast.c
index e9ebb56..72af738 100644
--- a/ast.c
+++ b/ast.c
@@ -4,6 +4,7 @@
 
 #include "util.h"
 #include "ast.h"
+#include "list.h"
 #include "parse.h"
 
 const char *binop_str[] = {
diff --git a/parse.y b/parse.y
index 6229385..8a8dca7 100644
--- a/parse.y
+++ b/parse.y
@@ -2,6 +2,7 @@
 #include <stdio.h>
 
 #include "ast.h"
+#include "list.h"
 #include "parse.h"
 
 int yylex(void);
diff --git a/scc.c b/scc.c
index 3c690a2..a3743e2 100644
--- a/scc.c
+++ b/scc.c
@@ -14,11 +14,6 @@ struct node {
 	void *data;
 };
 
-struct edge2 {
-	struct node *from;
-	struct node *to;
-};
-
 int ptrcmp(const void *l, const void *r)
 {
 	return ((ptrdiff_t)((struct node *)l)->data)
@@ -31,7 +26,7 @@ int nodecmp(const void *l, const void *r)
 }
 
 struct components *strongconnect(struct node *v, struct node **stack, int *sp,
-	int *index, int nedges, struct edge2 *edges, struct components *components)
+	int *index, int nedges, struct edge *edges, struct components *components)
 {
 	struct node *w;
 	v->index = *index;
@@ -76,7 +71,7 @@ struct components *scc(int nnodes, void **nodedata, int nedges, struct edge *edg
 			.onStack=false, .data=nodedata[i]};
 	qsort(nodes, nnodes, sizeof(struct node), ptrcmp);
 
-	struct edge2 *edges = safe_malloc(nedges*sizeof(struct edge2));
+	struct edge *edges = safe_malloc(nedges*sizeof(struct edge));
 	for (int i = 0; i<nedges; i++) {
 		struct node *from = bsearch(edgedata[i].from, nodes, nnodes,
 			sizeof(struct node), nodecmp);
@@ -90,7 +85,7 @@ struct components *scc(int nnodes, void **nodedata, int nedges, struct edge *edg
 			fprintf(stderr, "edge to references unknown node\n");
 			goto end;
 		}
-		edges[i] = (struct edge2){.from=from, .to=to};
+		edges[i] = (struct edge){.from=from, .to=to};
 	}
 
 	struct node **stack = safe_malloc(nnodes*sizeof(struct node *));
diff --git a/scc.h b/scc.h
index d7c378e..2392556 100644
--- a/scc.h
+++ b/scc.h
@@ -1,7 +1,6 @@
 #ifndef SCC_H
 #define SCC_H
 
-#include <stdbool.h>
 struct edge {
 	void *from;
 	void *to;
@@ -33,6 +32,6 @@ struct components *scc(int nnodes, void **nodedata, int nedges, struct edge *edg
  * @param cs components
  * @param freefun function to free the data with, if NULL, data isn't freed
  */
-void components_free(struct components *cs, void (*free)(void *));
+void components_free(struct components *cs, void (*freefun)(void *));
 
 #endif
diff --git a/type.c b/type.c
index f1828bc..3325de8 100644
--- a/type.c
+++ b/type.c
@@ -1,5 +1,34 @@
 #include "ast.h"
 
+void type_error(const char *msg, ...)
+{
+	va_list ap;
+	va_start(ap, msg);
+	fprintf(stderr, "type error: ");
+	vfprintf(stderr, msg, ap);
+	va_end(ap);
+	die("");
+}
+
+void check_expr_constant(struct expr *expr)
+{
+	switch (expr->type) {
+	case ebinop:
+		check_expr_constant(expr->data.ebinop.l);
+		check_expr_constant(expr->data.ebinop.r);
+		break;
+	case eunop:
+		check_expr_constant(expr->data.eunop.l);
+		break;
+	case efuncall:
+	case eident:
+		type_error("Initialiser is not constant\n");
+		break;
+	default:
+		break;
+	}
+}
+
 struct vardecl *type_vardecl(struct vardecl *vardecl)
 {
 	return vardecl;
@@ -23,7 +52,13 @@ struct decl *type_decl(struct decl *decl)
 
 struct ast *type(struct ast *ast)
 {
-	for (int i = 0; i<ast->ndecls; i++)
-		ast->decls[i] = type_decl(ast->decls[i]);
+	for (int i = 0; i<ast->ndecls; i++) {
+		if (ast->decls[i]->type == dvardecl) {
+			//Check globals
+			check_expr_constant(ast->decls[i]->data.dvar->expr);
+			break;
+		}
+	}
 	return ast;
 }
+
-- 
2.20.1