ref: a43a8ede995f69063e33713f304d5ced7b5b3edb
parent: 9af861a9ca611b8b04d0cb6d7713adae1ef0494b
author: Roberto E. Vargas Caballero <[email protected]>
date: Tue Aug 5 06:41:09 EDT 2014
Calculate addresability of statements Every node of the tree is labeled with a small number that indicate the addresability of the node. The algorithm is taken from [1], and basically it has a table where all the expressions directly addresable assign a number, and expressions that are not directly addresable are marked. [1] Plan 9 C Compilers: http://plan9.bell-labs.com/sys/doc/compiler.html
--- a/cc2/Makefile
+++ b/cc2/Makefile
@@ -1,5 +1,5 @@
-OBJS = main.o parser.o
+OBJS = main.o parser.o cgen.o
CPPFLAGS = -I../inc
LDFLAGS = -L../lib
@@ -7,7 +7,7 @@
all: cc2
-$(OBJS): ../inc/cc.h ../inc/sizes.h
+$(OBJS): ../inc/cc.h ../inc/sizes.h cc2.h
cc2: $(OBJS) ../lib/libcc.a
$(CC) $(LDFLAGS) $(CFLAGS) $(OBJS) $(LIBS) -o $@
--- /dev/null
+++ b/cc2/cc2.h
@@ -1,0 +1,25 @@
+
+typedef struct {+ union {+ struct {+ char type;
+ char storage;
+ } v;
+ struct {+ short addr;
+ } l;
+ } u;
+} Symbol;
+
+typedef struct node {+ char op;
+ char type;
+ int8_t sethi;
+ int8_t addrtype;
+ union {+ short id;
+ int imm;
+ } u;
+ struct node *left, *right;
+} Node;
+
--- /dev/null
+++ b/cc2/cgen.c
@@ -1,0 +1,53 @@
+
+#include <assert.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include "cc2.h"
+
+struct addrtype {+ char op;
+ char left;
+ char right;
+ char addrtype;
+} addrtbl[] = {+ {'A', 0, 0, 1},+ {'#', 0, 0, 2},+ {'+', 1, 2, 3},+ {0},+};
+
+struct nodeattr {+ char addrtype;
+ char sethi;
+};
+
+struct nodeattr
+genaddr(Node *np)
+{+ struct nodeattr left, right;
+ struct addrtype *bp;
+
+ left = (np->left) ? genaddr(np->left) : (struct nodeattr) {0, -1};+ right = (np->right) ? genaddr(np->right) : (struct nodeattr) {0, -1};+
+ for (bp = addrtbl; bp->op; ++bp) {+ if (bp->op == np->op &&
+ left.addrtype == bp->left &&
+ right.addrtype == bp->right) {+ break;
+ }
+ }
+
+ if ((np->addrtype = bp->addrtype) == 0) {+ np->sethi = 0;
+ } else if (right.sethi < 0) {+ np->sethi = (left.sethi > 1) ? left.sethi : 1;
+ } else {+ int8_t d = left.sethi - right.sethi;
+ np->sethi = ((d < 0) ? right.sethi : left.sethi) + 1;
+ }
+
+ return (struct nodeattr) {np->addrtype, np->sethi};+}
+
--- a/cc2/parser.c
+++ b/cc2/parser.c
@@ -1,10 +1,13 @@
#include <ctype.h>
+#include <stdint.h>
#include <stdio.h>
#include <cc.h>
#include <sizes.h>
+#include "cc2.h"
+
#define STR(x) XSTR(x)
#define XSTR(x) #x
@@ -13,28 +16,6 @@
#define NR_EXPRESSIONS 64
#define NR_SYMBOLS 1024
-typedef struct {- union {- struct {- char type;
- char storage;
- } v;
- struct {- short addr;
- } l;
- } u;
-} Symbol;
-
-typedef struct node {- char op;
- char type;
- union {- short id;
- int imm;
- } u;
- struct node *left, *right;
-} Node;
-
static Node *stack[NR_STACKSIZ], **stackp = stack;
static Node *listexp[NR_EXPRESSIONS], **listp = &listexp[0];
static Node nodepool[NR_NODEPOOL], *newp = nodepool;
@@ -248,10 +229,11 @@
}
}
-int
+void
parse(void)
{int c;
+ void genaddr(Node *np);
for (;;) { switch (c = getchar()) {@@ -260,6 +242,7 @@
break;
case 'X':
function();
+ genaddr(listexp[0]);
break;
case EOF:
return;
--- /dev/null
+++ b/cgen.c
@@ -1,0 +1,53 @@
+
+#include <assert.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include "cc2.h"
+
+struct addrtype {+ char op;
+ char left;
+ char right;
+ char addrtype;
+} addrtbl[] = {+ {'A', 0, 0, 1},+ {'#', 0, 0, 2},+ {'+', 1, 2, 3},+ {0},+};
+
+struct nodeattr {+ char addrtype;
+ char sethi;
+};
+
+struct nodeattr
+genaddr(Node *np)
+{+ struct nodeattr left, right;
+ struct addrtype *bp;
+
+ left = (np->left) ? genaddr(np->left) : (struct nodeattr) {0, -1};+ right = (np->right) ? genaddr(np->right) : (struct nodeattr) {0, -1};+
+ for (bp = addrtbl; bp->op; ++bp) {+ if (bp->op == np->op &&
+ left.addrtype == bp->left &&
+ right.addrtype == bp->right) {+ break;
+ }
+ }
+
+ if ((np->addrtype = bp->addrtype) == 0) {+ np->sethi = 0;
+ } else if (right.sethi < 0) {+ np->sethi = (left.sethi > 1) ? left.sethi : 1;
+ } else {+ int8_t d = left.sethi - right.sethi;
+ np->sethi = ((d < 0) ? right.sethi : left.sethi) + 1;
+ }
+
+ return (struct nodeattr) {np->addrtype, np->sethi};+}
+