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Free expressions after using them

We were not freeing memory, so with big files this was a problem. This patch
adds a first solution to this problem, but something better must be done,
because in this moment one type is created by every function.

--- a/cc1/cc1.h

+++ b/cc1/cc1.h

@@ -157,6 +157,7 @@

 	void (*code)(struct node *);

 	Type *type;

 	uint8_t typeop;

+	uint8_t nchilds;

 	struct {

 		bool lvalue : 1;

 		bool symbol: 1;

@@ -208,6 +209,8 @@

 	*ternarycode(Node *cond, Node *ifyes, Node *ifno),

 	*symcode(Symbol *sym),

 	*fieldcode(Node *child, struct field *fp);

+

+extern void freetree(Node *np);

 #define NEGATE(n, v) ((n)->u.op ^= (v))

 /* TODO: remove some of these ugly macros */

--- a/cc1/code.c

+++ b/cc1/code.c

@@ -1,6 +1,7 @@

 #include <stdint.h>

 #include <stdio.h>

+#include <stdlib.h>

 #include <cc.h>

 #include "cc1.h"

@@ -58,10 +59,24 @@

 	np->code = code;

 	np->type = tp;

 	np->typeop = tp->op;

+	np->nchilds = nchilds;

 	np->u = u;

 	np->b.symbol = np->b.lvalue = 0;

 	return np;

+}

+

+void

+freetree(Node *np)

+{

+	Node **p;

+

+	if (!np)

+		return;

+

+	for (p = np->childs; np->nchilds--; ++p)

+		freetree(*p);

+	free(np);

 }

 static void

--- a/cc1/stmt.c

+++ b/cc1/stmt.c

@@ -46,9 +46,15 @@

 static void

 stmtexp(Symbol *lbreak, Symbol *lcont, Caselist *lswitch)

 {

-	if (yytoken != ';')

-		emitexp(expr());

+	Node *np = NULL;;

+

+	if (yytoken != ';') {

+		np = expr();

+		emitexp(np);

+	}

+

 	expect(';');

+	freetree(np);

 }

 static Node *

@@ -82,6 +88,7 @@

 	emitjump(begin, np);

 	emiteloop();

 	emitlabel(end);

+	freetree(np);

 }

 static void

@@ -113,6 +120,9 @@

 	emitjump(begin, econd);

 	emiteloop();

 	emitlabel(end);

+	freetree(einit);

+	freetree(econd);

+	freetree(einc);

 }

 static void

@@ -119,6 +129,7 @@

 Dowhile(Symbol *lbreak, Symbol *lcont, Caselist *lswitch)

 {

 	Symbol *begin, *end;

+	Node *np;

 	begin = install("", NS_LABEL);

 	end = install("", NS_LABEL);

@@ -127,9 +138,11 @@

 	emitlabel(begin);

 	stmt(end, begin, lswitch);

 	expect(WHILE);

-	emitjump(begin, condition());

+	np = condition();

+	emitjump(begin, np);

 	emiteloop();

 	emitlabel(end);

+	freetree(np);

 }

 static void

@@ -153,6 +166,7 @@

 	}

 	emitret(tp);

 	emitexp(np);

+	freetree(np);

 }

 static void

@@ -229,11 +243,13 @@

 	for (p = lcase.head; p; p = next) {

 		emitcase(p->label, p->expr);

 		next = p->next;

+		freetree(p->expr);

 		free(p);

 	}

 	if (lcase.deflabel)

 		emitdefault(lcase.deflabel);

 	emitlabel(lbreak);

+	freetree(cond);

 }

 static void

@@ -289,6 +305,7 @@

 	} else {

 		emitlabel(lelse);

 	}

+	freetree(np);

 }

 void

@@ -318,6 +335,7 @@

 stmt(Symbol *lbreak, Symbol *lcont, Caselist *lswitch)

 {

 	void (*fun)(Symbol *lbreak, Symbol *lcont, Caselist *lswitch);

+	Node *np;

 	switch (yytoken) {

 	case '{':      fun = context;  break;

@@ -338,7 +356,9 @@

 		break;

 	case '@':

 		next();

-		emitprint(expr());

+		np = expr();

+		emitprint(np);

+		freetree(np);

 		return;

 	}

 	(*fun)(lbreak, lcont, lswitch);

-- 

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