Some tests for passing and returning structures by value on x64. Close #1402. Close #1970.

Author: graydon

src/rt/rust_builtin.cpp

@@ -200,6 +200,43 @@ rand_free(randctx *rctx) {
     task->free(rctx);
 }
 
+
+/* Debug helpers strictly to verify ABI conformance.
+ *
+ * FIXME: move these into a testcase when the testsuite
+ * understands how to have explicit C files included.
+ */
+
+struct quad {
+    uint64_t a;
+    uint64_t b;
+    uint64_t c;
+    uint64_t d;
+};
+
+struct floats {
+    double a;
+    uint8_t b;
+    double c;
+};
+
+extern "C" quad
+debug_abi_1(quad q) {
+    quad qq = { q.c + 1,
+                q.d - 1,
+                q.a + 1,
+                q.b - 1 };
+    return qq;
+}
+
+extern "C" floats
+debug_abi_2(floats f) {
+    floats ff = { f.c + 1.0,
+                  0xff,
+                  f.a - 1.0 };
+    return ff;
+}
+
 /* Debug builtins for std::dbg. */
 
 static void

src/rt/rustrt.def.in

@@ -7,6 +7,8 @@ debug_ptrcast
 debug_tag
 debug_tydesc
 debug_get_stk_seg
+debug_abi_1
+debug_abi_2
 get_port_id
 get_task_id
 get_time

src/test/run-pass/struct-return.rs

@@ -0,0 +1,39 @@
+
+type quad = { a: u64, b: u64, c: u64, d: u64 };
+type floats = { a: f64, b: u8, c: f64 };
+
+#[nolink]
+native mod rustrt {
+    fn debug_abi_1(++q: quad) -> quad;
+    fn debug_abi_2(++f: floats) -> floats;
+}
+
+fn main() {
+
+    // First check
+    let q = { a: 0xaaaa_aaaa_aaaa_aaaa_u64,
+             b: 0xbbbb_bbbb_bbbb_bbbb_u64,
+             c: 0xcccc_cccc_cccc_cccc_u64,
+             d: 0xdddd_dddd_dddd_dddd_u64 };
+    let qq = rustrt::debug_abi_1(q);
+    #error("a: %x", qq.a as uint);
+    #error("b: %x", qq.b as uint);
+    #error("c: %x", qq.c as uint);
+    #error("d: %x", qq.d as uint);
+    assert qq.a == q.c + 1u64;
+    assert qq.b == q.d - 1u64;
+    assert qq.c == q.a + 1u64;
+    assert qq.d == q.b - 1u64;
+
+    // Second check
+    let f = { a: 1.234567890e-15_f64,
+             b: 0b_1010_1010_u8,
+             c: 1.0987654321e-15_f64 };
+    let ff = rustrt::debug_abi_2(f);
+    #error("a: %f", ff.a as float);
+    #error("b: %u", ff.b as uint);
+    #error("c: %f", ff.c as float);
+    assert ff.a == f.c + 1.0;
+    assert ff.b == 0xff_u8;
+    assert ff.c == f.a - 1.0;
+}