Add test of bit-field packing for #1054 and #1055

test/val/bitfield.c

@@ -0,0 +1,124 @@
+/*
+  !!DESCRIPTION!! Tests of bit-field packing
+  !!ORIGIN!!      cc65 regression tests
+  !!LICENCE!!     zlib
+  !!AUTHOR!!      Jesse Rosenstock
+*/
+
+/*
+  see https://github.com/cc65/cc65/issues/1054
+*/
+
+#include <stdio.h>
+
+static unsigned char failures = 0;
+
+static struct four_bits {
+    unsigned int x : 4;
+} fb = {1};
+
+static void test_four_bits(void)
+{
+    if (sizeof(struct four_bits) != 1) {
+        fprintf(stderr, "Got sizeof(struct four_bits) = %zu, expected 1.\n",
+                sizeof(struct four_bits));
+        failures++;
+    }
+
+    if (fb.x != 1) {
+        fprintf(stderr, "Got fb.x = %u, expected 1.\n", fb.x);
+        failures++;
+    }
+
+    fb.x = 3;
+
+    if (fb.x != 3) {
+        fprintf(stderr, "Got fb.x = %u, expected 3.\n", fb.x);
+        failures++;
+    }
+}
+
+static struct four_bits_with_int {
+    unsigned int x : 4;
+    unsigned int y;
+} fbi = {1, 2};
+
+static void test_four_bits_with_int(void)
+{
+    /* We would like this to be 3.  https://github.com/cc65/cc65/issues/1054 */
+    if (sizeof(struct four_bits_with_int) != 4) {
+        fprintf(stderr,
+                "Got sizeof(struct four_bits_with_int) = %zu, expected 4.\n",
+                sizeof(struct four_bits_with_int));
+        failures++;
+    }
+
+    if (fbi.x != 1) {
+        fprintf(stderr, "Got fbi.x = %u, expected 1.\n", fbi.x);
+        failures++;
+    }
+
+    if (fbi.y != 2) {
+        fprintf(stderr, "Got fbi.y = %u, expected 2.\n", fbi.y);
+        failures++;
+    }
+
+    fbi.x = 3;
+    fbi.y = 17;
+
+    if (fbi.x != 3) {
+        fprintf(stderr, "Got fbi.x = %u, expected 3.\n", fbi.x);
+        failures++;
+    }
+
+    if (fbi.y != 17) {
+        fprintf(stderr, "Got fbi.y = %u, expected 17.\n", fbi.y);
+        failures++;
+    }
+}
+
+static struct overlap {
+    unsigned int x : 10;
+    unsigned int y : 10;
+} o = {11, 22};
+
+/* Tests that bit-fields can share allocation units. */
+static void test_overlap(void)
+{
+    if (sizeof(struct overlap) != 3) {
+        fprintf(stderr, "Got sizeof(struct overlap) = %zu, expected 3.\n",
+                sizeof(struct overlap));
+        failures++;
+    }
+
+    if (o.x != 11) {
+        fprintf(stderr, "Got o.x = %u, expected 11.\n", o.x);
+        failures++;
+    }
+
+    if (o.y != 22) {
+        fprintf(stderr, "Got o.y = %u, expected 22.\n", o.y);
+        failures++;
+    }
+
+    o.x = 33;
+    o.y = 44;
+
+    if (o.x != 33) {
+        fprintf(stderr, "Got o.x = %u, expected 33.\n", o.x);
+        failures++;
+    }
+
+    if (o.y != 44) {
+        fprintf(stderr, "Got o.y = %u, expected 44.\n", o.y);
+        failures++;
+    }
+}
+
+int main(void)
+{
+    test_four_bits();
+    test_four_bits_with_int();
+    test_overlap();
+    return failures;
+}