scc

commit fea73f0b34c2e192b38362e6468870a1c1ce312a
parent ecf29f6e95d44f013c47a2d907eea21b2bb5d934
Author: Roberto E. Vargas Caballero <k0ga@shike2.com>
Date:   Thu, 26 Dec 2024 22:19:00 +0100

cc2: Add information about basic blocks

Nodes can be grouped into basic blocks composed of a set
of consecutive statements without branches or jumps that
are executed sequentially from the entry point to the
exit point.

Diffstat:
M
src/cmd/scc-cc/cc2/cc2.h
 | 
11
+++++++++++
M
src/cmd/scc-cc/cc2/node.c
 | 
12
+++++++++++-

2 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/src/cmd/scc-cc/cc2/cc2.h b/src/cmd/scc-cc/cc2/cc2.h
@@ -2,6 +2,7 @@
 
 enum iflags {
 	BBENTRY =    1,        /* basic block entry */
+	BBEXIT  =    2,        /* basic block exit */
 };
 
 enum tflags {
@@ -152,6 +153,7 @@ typedef struct type Type;
 typedef struct symbol Symbol;
 typedef struct addr Addr;
 typedef struct inst Inst;
+typedef struct block Block;
 
 struct type {
 	unsigned long size;
@@ -193,10 +195,19 @@ struct node {
 		long off;
 	} u;
 	Symbol *label;
+	Block *bb;
 	Node *left, *right;
 	Node *next, *prev;
 };
 
+struct block {
+	int id;
+	int printed, visited;
+	Node *entryp, *exitp;
+	Block *true, *false;
+	Block *next;
+};
+
 struct addr {
 	char kind;
 	union {
diff --git a/src/cmd/scc-cc/cc2/node.c b/src/cmd/scc-cc/cc2/node.c
@@ -43,6 +43,16 @@ prnode(Node *np)
 void
 prtree(Node *np)
 {
+	Block *bb;
+
+	bb = np->bb;
+
+	if (np->flags & BBENTRY)
+		putc('>', stderr);
+	fprintf(stderr, "(%d)",  bb ? bb->id : 0);
+	if (np->flags & BBEXIT)
+		putc('>', stderr);
+
 	prnode(np);
 	putc('\n', stderr);
 }
@@ -55,7 +65,7 @@ prforest(char *msg)
 	if (!curfun)
 		return;
 
-	fprintf(stderr, "%s {\n", msg);
+	fprintf(stderr, "tree %s {\n", msg);
 	for (np = curfun->u.stmt; np; np = np->next)
 		prtree(np);
 	fputs("}\n", stderr);