From 09cdf87f67fe4638f8d8c8968b0e9173bfd227fa Mon Sep 17 00:00:00 2001
From: Bill Currie <bill@taniwha.org>
Date: Tue, 29 Aug 2023 13:59:12 +0900
Subject: [PATCH] [qfcc] Used aligned type sizes for sizeof

And geometric algebra vectors. This does break things a little in GA,
but it does bring qfcc's C closer to standard C in that sizeof respects
the alignment of the type (very important for arrays).
---
 tools/qfcc/include/type.h   |  1 +
 tools/qfcc/source/algebra.c | 20 +++++++++++++++++++-
 tools/qfcc/source/expr.c    |  2 +-
 tools/qfcc/source/type.c    |  7 +++++++
 tools/qfcc/test/pga2d.r     |  8 +++++---
 5 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/tools/qfcc/include/type.h b/tools/qfcc/include/type.h
index 7391d872d..337d0f4fa 100644
--- a/tools/qfcc/include/type.h
+++ b/tools/qfcc/include/type.h
@@ -230,6 +230,7 @@ int type_promotes (const type_t *dst, const type_t *src) __attribute__((pure));
 int type_same (const type_t *dst, const type_t *src) __attribute__((pure));
 int type_size (const type_t *type) __attribute__((pure));
 int type_width (const type_t *type) __attribute__((pure));
+int type_aligned_size (const type_t *type) __attribute__((pure));
 
 void init_types (void);
 void chain_initial_types (void);
diff --git a/tools/qfcc/source/algebra.c b/tools/qfcc/source/algebra.c
index fdaa7e99b..e0447a0bf 100644
--- a/tools/qfcc/source/algebra.c
+++ b/tools/qfcc/source/algebra.c
@@ -445,6 +445,11 @@ algebra_subtype (type_t *type, attribute_t *attr)
 static int
 algebra_alignment (const type_t *type, int width)
 {
+	if (width > 4) {
+		// don't need more than 4 units
+		width = 4;
+	}
+	// alignment reflects the size for doubles vs floats
 	return type->alignment * BITOP_RUP (width);
 }
 
@@ -657,7 +662,20 @@ algebra_type_size (const type_t *type)
 		return a->num_components * type_size (a->type);
 	} else if (type->type == ev_float || type->type == ev_double) {
 		auto m = type->t.multivec;
-		return m->num_components * type_size (m->algebra->type);
+		auto a = m->algebra;
+		auto layout = &a->layout;
+		int  size = 0;
+		if (m->group_mask & (m->group_mask - 1)) {
+			for (int i = 0; i < layout->count; i++) {
+				if (m->group_mask & (1u << i)) {
+					auto t = algebra_mvec_type (a, m->group_mask & (1u << i));
+					size += type_aligned_size (t);
+				}
+			}
+		} else {
+			size = m->num_components * type_size (m->algebra->type);
+		}
+		return size;
 	} else {
 		internal_error (0, "invalid algebra type");
 	}
diff --git a/tools/qfcc/source/expr.c b/tools/qfcc/source/expr.c
index 095c16d9e..e895e7efc 100644
--- a/tools/qfcc/source/expr.c
+++ b/tools/qfcc/source/expr.c
@@ -3009,7 +3009,7 @@ sizeof_expr (expr_t *expr, struct type_s *type)
 	if (!type)
 		type = get_type (expr);
 	if (type) {
-		expr = new_int_expr (type_size (type));
+		expr = new_int_expr (type_aligned_size (type));
 	}
 	return expr;
 }
diff --git a/tools/qfcc/source/type.c b/tools/qfcc/source/type.c
index 463a986b9..5b40aa6a6 100644
--- a/tools/qfcc/source/type.c
+++ b/tools/qfcc/source/type.c
@@ -1444,6 +1444,13 @@ type_width (const type_t *type)
 	internal_error (0, "invalid type meta: %d", type->meta);
 }
 
+int
+type_aligned_size (const type_t *type)
+{
+	int         size = type_size (type);
+	return RUP (size, type->alignment);
+}
+
 static void
 chain_basic_types (void)
 {
diff --git a/tools/qfcc/test/pga2d.r b/tools/qfcc/test/pga2d.r
index 6074fd46d..c2c427d2b 100644
--- a/tools/qfcc/test/pga2d.r
+++ b/tools/qfcc/test/pga2d.r
@@ -27,11 +27,13 @@ main (void)
 		printf ("scalar has wrong size: %d\n", sizeof (scalar_t));
 		return 1;
 	}
-	if (sizeof (vector_t) != 3 * sizeof (scalar_t)) {
-		printf ("bivector has wrong size: %d\n", sizeof (vector_t));
+	// vector_t is a vec3 but has alignment of 4 thus sizeof of 4 * scalar
+	if (sizeof (vector_t) != 4 * sizeof (scalar_t)) {
+		printf ("vector has wrong size: %d\n", sizeof (vector_t));
 		return 1;
 	}
-	if (sizeof (bivector_t) != 3 * sizeof (scalar_t)) {
+	// bivector_t is a vec3 but has alignment of 4 thus sizeof of 4 * scalar
+	if (sizeof (bivector_t) != 4 * sizeof (scalar_t)) {
 		printf ("bivector has wrong size: %d\n", sizeof (bivector_t));
 		return 1;
 	}