From 1e66f1ce8a8df863042ab54ba6b68bd6d2e52396 Mon Sep 17 00:00:00 2001
From: Michael Forney <mforney@mforney.org>
Date: Sun, 7 Apr 2024 13:15:31 -0700
Subject: Store length expression in array types

We don't need the length constant anymore, so just use that name
for the length expression.

References: https://todo.sr.ht/~mcf/cproc/1
---
 cc.h   |  2 +-
 decl.c | 26 ++++++++++++++++----------
 targ.c |  2 +-
 type.c |  2 +-
 4 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/cc.h b/cc.h
index d659872..068eb72 100644
--- a/cc.h
+++ b/cc.h
@@ -219,7 +219,7 @@ struct type {
 			bool issigned, iscomplex;
 		} basic;
 		struct {
-			unsigned long long length;
+			struct expr *length;
 			enum typequal ptrqual;
 		} array;
 		struct {
diff --git a/decl.c b/decl.c
index 2fb56c4..0075baf 100644
--- a/decl.c
+++ b/decl.c
@@ -542,7 +542,6 @@ declaratortypes(struct scope *s, struct list *result, char **name, bool allowabs
 	struct type *t;
 	struct param **p;
 	struct expr *e;
-	unsigned long long i;
 	enum typequal tq;
 	bool allowattr;
 
@@ -649,14 +648,10 @@ declaratortypes(struct scope *s, struct list *result, char **name, bool allowabs
 			if (tok.kind == TMUL)
 				error(&tok.loc, "VLAs are not yet supported");
 			if (tok.kind != TRBRACK) {
-				e = eval(assignexpr(s));
-				if (e->kind != EXPRCONST || !(e->type->prop & PROPINT))
-					error(&tok.loc, "VLAs are not yet supported");
-				i = e->u.constant.u;
-				if (e->type->u.basic.issigned && i >> 63)
-					error(&tok.loc, "array length must be non-negative");
-				delexpr(e);
-				t->u.array.length = i;
+				e = assignexpr(s);
+				if (!(e->type->prop & PROPINT))
+					error(&tok.loc, "array length expression must have integer type");
+				t->u.array.length = e;
 				t->incomplete = false;
 			}
 			expect(TRBRACK, "after array length");
@@ -681,6 +676,7 @@ declarator(struct scope *s, struct qualtype base, char **name, bool allowabstrac
 {
 	struct type *t;
 	enum typequal tq;
+	struct expr *e;
 	struct list result = {&result, &result}, *l, *prev;
 
 	declaratortypes(s, &result, name, allowabstract);
@@ -703,7 +699,17 @@ declarator(struct scope *s, struct qualtype base, char **name, bool allowabstrac
 			if (base.type->kind == TYPEFUNC)
 				error(&tok.loc, "array element has function type");
 			t->align = base.type->align;
-			t->size = base.type->size * t->u.array.length;  /* XXX: overflow? */
+			t->size = 0;
+			if (t->u.array.length) {
+				e = eval(t->u.array.length);
+				if (e->kind != EXPRCONST)
+					error(&tok.loc, "VLAs are not yet supported");
+				if (e->type->u.basic.issigned && e->u.constant.u >> 63)
+					error(&tok.loc, "array length must be non-negative");
+				if (e->u.constant.u > ULLONG_MAX / base.type->size)
+					error(&tok.loc, "array length is too large");
+				t->size = base.type->size * e->u.constant.u;
+			}
 			break;
 		}
 		base.type = t;
diff --git a/targ.c b/targ.c
index 9d0c179..b52c876 100644
--- a/targ.c
+++ b/targ.c
@@ -12,7 +12,7 @@ static const struct target alltargs[] = {
 		.typevalist = &(struct type){
 			.kind = TYPEARRAY,
 			.align = 8, .size = 24,
-			.u.array = {1}, .base = &(struct type){
+			.base = &(struct type){
 				.kind = TYPESTRUCT,
 				.align = 8, .size = 24,
 			},
diff --git a/type.c b/type.c
index 0aaff36..6798105 100644
--- a/type.c
+++ b/type.c
@@ -79,7 +79,7 @@ mkarraytype(struct type *base, enum typequal qual, unsigned long long len)
 	t = mktype(TYPEARRAY, 0);
 	t->base = base;
 	t->qual = qual;
-	t->u.array.length = len;
+	t->u.array.length = NULL;
 	t->u.array.ptrqual = QUALNONE;
 	t->incomplete = !len;
 	if (t->base) {
-- 
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