scc

commit d68b3d817cf4b252524880eb9408d2f4b3b596ef
parent a1a0f635df0811a394b3662dea887d4ba0eb089b
Author: Roberto E. Vargas Caballero <k0ga@shike2.com>
Date:   Thu, 21 Sep 2017 12:34:12 +0100

[as] Add temporaries symbols

These symbols are used for constants in the code and
for folded values. They are freed at the end of every
pass.

Diffstat:
M
as/as.h
 | 
2
++
M
as/expr.c
 | 
19
+++++++++++++++----
M
as/main.c
 | 
14
+++++++++++---
M
as/symbol.c
 | 
24
++++++++++++++++++++++++

4 files changed, 52 insertions(+), 7 deletions(-)
diff --git a/as/as.h b/as/as.h
@@ -102,6 +102,8 @@ extern void isections(void);
 extern void writeout(char *name);
 extern void emit(Section *sec, char *bytes, int nbytes);
 extern Section *section(char *name);
+extern Symbol *tmpsym(TUINT val);
+extern void killtmp(void);
 
 /* main.c */
 extern Symbol *lookup(char *name);
diff --git a/as/expr.c b/as/expr.c
@@ -14,7 +14,6 @@ enum tokens {
 	IDEN = 1,
 	NUMBER,
 	REG,
-	CHAR,
 	STRING,
 	SHL,
 	SHR,
@@ -22,10 +21,16 @@ enum tokens {
 	LE,
 };
 
+union yylval {
+	TUINT val;
+	Symbol *sym;
+};
+
 static Alloc *arena;
 static int yytoken;
 static char yytext[INTIDENTSIZ+1], *textp, *endp;
 static size_t yylen;
+static union yylval yylval;
 
 #define accept(t) (yytoken == (t) ? next() : 0)
 
@@ -121,7 +126,7 @@ binary(int op, Node *l, Node *r)
 	}
 
 	np = node(NUMBER, l, r);
-	/* np->sym = tmpsym(val); */
+	np->sym = tmpsym(val);
 	return np;
 
 division_by_zero:
@@ -172,6 +177,9 @@ iden(void)
 
 	for (endp = textp; isalnum(c = *endp) || c == '_' || c == '.'; ++endp)
 		/* nothing */;
+	tok2str();
+	yylval.sym = lookup(yytext);
+
 	return IDEN;
 }
 
@@ -183,6 +191,9 @@ number(void)
 
 	for (endp = textp; isxdigit(*endp); ++endp)
 		/* nothing */;
+	tok2str();
+	yylval.sym = tmpsym(atoi(yytext));  /* TODO: parse the string */
+
 	return NUMBER;
 }
 
@@ -194,7 +205,7 @@ character(void)
 
 	for (endp = textp+1; *endp != '\''; ++endp)
 		/* nothing */;
-	return CHAR;
+	return NUMBER;
 }
 
 static int
@@ -261,9 +272,9 @@ primary(void)
 	switch (yytoken) {
 	case NUMBER:
 	case IDEN:
-	case CHAR:
 	case STRING:
 		np = node(yytoken, NULL, NULL);
+		np->sym = yylval.sym;
 		next();
 		break;
 	case '(':
diff --git a/as/main.c b/as/main.c
@@ -72,6 +72,13 @@ dopass(char *fname)
 
 	if (fclose(fp))
 		die("as: error reading from input file '%s'", fname);
+	if (pass == 2)
+		writeout("a.out");
+	/*
+	 * kill tmp symbols because they are not needed anymore
+	 */
+	killtmp();
+
 	return nerrors == 0;
 }
 
@@ -89,9 +96,10 @@ main(int argc, char *argv[])
 		usage();
 
 	filename = argv[1];
-	for (pass = 1; pass <= 2 && dopass(filename); pass++)
-		/* nothing */;
-	writeout("a.out");
+	for (pass = 1; pass <= 2; pass++) {
+		if (!dopass(filename))
+			return 1;
+	}
 
 	return 0;
 }
diff --git a/as/symbol.c b/as/symbol.c
@@ -8,6 +8,7 @@ static char sccsid[] = "@(#) ./as/emit.c";
 #include "as.h"
 
 #define HASHSIZ 64
+#define NALLOC  10
 
 static Section abss = {
 	.name  = "abs",
@@ -37,6 +38,8 @@ Section *cursec = &text, *headp = &text;
 int pass;
 
 static Symbol *hashtbl[HASHSIZ];
+static Alloc *tmpalloc;
+
 Symbol *linesym;
 
 Symbol *
@@ -201,6 +204,27 @@ emit(Section *sec, char *bytes, int n)
 	incpc(n);
 }
 
+Symbol *
+tmpsym(TUINT val)
+{
+	Symbol *sym;
+
+	if (!tmpalloc)
+		tmpalloc = alloc(sizeof(*sym), NALLOC);
+	sym = new(tmpalloc);
+	sym->value = val;
+	sym->flags = TABS;
+
+	return sym;
+}
+
+void
+killtmp(void)
+{
+	dealloc(tmpalloc);
+	tmpalloc = NULL;
+}
+
 void
 writeout(char *name)
 {