scc

commit 35e9f657a7d01cd0cc060ccaf671764227ef06b6
parent e72e0e9184bf0aa2fc6551816ad6f3f1b36a4d53
Author: Roberto E. Vargas Caballero <k0ga@shike2.com>
Date:   Fri, 27 Dec 2024 12:01:19 +0100

cc2: Add insstmt()

This function allows to insert a statement after a specific
statement and it avoids using curstmt out of node.c.

Diffstat:
M
src/cmd/scc-cc/cc2/cc2.h
 | 
1
+
M
src/cmd/scc-cc/cc2/node.c
 | 
24
+++++++++++++++++++++++-
M
src/cmd/scc-cc/cc2/parser.c
 | 
17
++---------------

3 files changed, 26 insertions(+), 16 deletions(-)
diff --git a/src/cmd/scc-cc/cc2/cc2.h b/src/cmd/scc-cc/cc2/cc2.h
@@ -266,6 +266,7 @@ extern Node *node(int op);
 extern Node *addstmt(Node *np, int flags);
 extern Node *delstmt(void);
 extern Node *nextstmt(void);
+extern Node *insstmt(Node *, Node *, int);
 
 /* symbol.c */
 #define TMPSYM  0
diff --git a/src/cmd/scc-cc/cc2/node.c b/src/cmd/scc-cc/cc2/node.c
@@ -12,11 +12,11 @@ struct function {
 	Node *end;
 };
 
-Node *curstmt;
 Symbol *curfun;
 
 static Alloc *arena;
 static struct function fn;
+static Node *curstmt;
 
 Node *
 node(int op)
@@ -77,6 +77,28 @@ prforest(char *msg)
 }
 #endif
 
+/*
+ * Insert a node after `at' and if mode is SETCUR
+ * update the current statement if `at' was the
+ * current statement
+ */
+Node *
+insstmt(Node *np, Node *at, int mode)
+{
+	Node *save;
+
+	save = curstmt;
+	curstmt = at;
+	addstmt(np, KEEPCUR);
+
+	if (mode == KEEPCUR)
+		curstmt = save;
+	else
+		curstmt = (save == at) ? np : save;
+
+	return np;
+}
+
 Node *
 addstmt(Node *np, int mode)
 {
diff --git a/src/cmd/scc-cc/cc2/parser.c b/src/cmd/scc-cc/cc2/parser.c
@@ -341,34 +341,21 @@ oreturn(char *token, union tokenop u)
 
 /*
  * Move np (which is a OCASE/ODEFAULT/OESWITCH) to be contigous with
- * the last switch table. It is a bit ugly to touch directly curstmt
- * here, but moving this function to node.c is worse, because we are
- * putting knowledge of how the text is parsed into the node
- * represtation module.
+ * the last switch table.
  */
 static void
 waft(Node *np)
 {
 	Node *lastcase, *next;
 	struct swtch *cur;
-	extern Node *curstmt;
 
 	if (swp == swtbl)
 		error(EWTACKU);
 
 	cur = swp - 1;
 	lastcase = cur->last;
-	next = lastcase->next;
+	insstmt(np, cur->last, SETCUR);
 
-	np->next = next;
-	np->prev = lastcase;
-
-	if (next)
-		next->prev = np;
-	lastcase->next = np;
-
-	if (curstmt == cur->last)
-		curstmt = np;
 	cur->last = np;
 	cur->nr++;
 }