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ref: c6c78143c4f439c038bfaf363b46352bd17d3430
parent: a4ef620605bf4c351c245fb921d898793e0a2470
author: Roberto E. Vargas Caballero <[email protected]>
date: Fri Apr 22 09:32:34 EDT 2016 

[cc2-qbe] Add allocation of parameters

Qbe needs explicitely allocate the stack space for the parameters,
which are considered only the values passed as parameters, not
the local variables that parameter are to.


--- a/cc2/arch/qbe/code.c
+++ b/cc2/arch/qbe/code.c
@@ -246,31 +246,53 @@
 	putchar('\n');
 }
 
+static void
+alloc(Symbol *sym)
+{
+	Type *tp = &sym->type;
+
+	printf("\t%s %s=\talloc%lld\t%lld\n",
+	       symname(sym), size2asm(tp),
+	       (long long) tp->size, (long long) tp->align);
+}
+
 void
 writeout(void)
 {
 	Symbol *p;
 	Type *tp;
-	char *sep;
+	char *sep, *name;
 
 	if (curfun->kind == SGLOB)
 		fputs("export ", stdout);
 	printf("function %s %s(", size2asm(&curfun->rtype), symname(curfun));
 
+	/* declare formal parameters */
 	for (sep = "", p = locals; p; p = p->next, sep = ",") {
 		if ((p->type.flags & PARF) == 0)
 			break;
-		printf("%s%s %s", sep, size2asm(&p->type), symname(p));
+		printf("%s%s %s.val", sep, size2asm(&p->type), symname(p));
 	}
-	puts(")");
+	puts(")\n{");
 
-	for ( ; p && p->id != TMPSYM; p = p->next) {
+	/* allocate stack space for parameters */
+	for (p = locals; p && (p->type.flags & PARF) == 0; p = p->next)
+		alloc(p);
+
+	/* allocate stack space for local variables) */
+	for ( ; p && p->id != TMPSYM; p = p->next)
+		alloc(p);
+
+	/* store formal parameters in parameters */
+	for (p = locals; p; p = p->next) {
 		tp = &p->type;
-		printf("\t%s %s=\talloc%lld\t%lld\n",
-		       symname(p), size2asm(tp),
-		       (long long) tp->size, (long long) tp->align);
+		if ((tp->flags & PARF) == 0)
+			break;
+		name = symname(p);
+		printf("\t\tstore%s\t%s.val,%s\n", size2asm(tp), name, name);
 	}
 
+	/* emit assembler instructions */
 	for (pc = prog; pc; pc = pc->next) {
 		if (pc->label)
 			printf("%s:\n", symname(pc->label));