auto merge of #7839 : graydon/rust/new-codegen-tests, r=pcwalton

Add some codegen tests. Nothing too surprising.

src/test/codegen/iterate-over-array.cc

@@ -0,0 +1,17 @@
+#include <stdlib.h>
+#include <assert.h>
+
+struct slice {
+  int const *p;
+  size_t len;
+};
+
+extern "C"
+size_t test(slice s) {
+  size_t y = 0;
+  for (int i = 0; i < s.len; ++i) {
+	assert(i < s.len);
+	y += s.p[i];
+  }
+  return y;
+}

src/test/codegen/iterate-over-array.rs

@@ -0,0 +1,10 @@
+#[no_mangle]
+fn test(x: &[int]) -> int {
+    let mut y = 0;
+    let mut i = 0;
+    while (i < x.len()) {
+        y += x[i];
+        i += 1;
+    }
+    y
+}

src/test/codegen/scalar-function-call.cc

@@ -0,0 +1,10 @@
+#include <stdlib.h>
+
+size_t foo(size_t x) {
+    return x * x;
+}
+
+extern "C"
+void test() {
+    size_t x = foo(10);
+}

src/test/codegen/scalar-function-call.rs

@@ -0,0 +1,8 @@
+fn foo(x: int) -> int {
+    x * x
+}
+
+#[no_mangle]
+fn test() {
+    let x = foo(10);
+}

src/test/codegen/small-dense-int-switch.cc

@@ -0,0 +1,11 @@
+#include <stdlib.h>
+
+extern "C"
+size_t test(size_t x, size_t y) {
+  switch (x) {
+  case 1: return y;
+  case 2: return y*2;
+  case 4: return y*3;
+  default: return 11;
+  }
+}

src/test/codegen/small-dense-int-switch.rs

@@ -0,0 +1,9 @@
+#[no_mangle]
+fn test(x: int, y: int) -> int {
+    match x {
+        1 => y,
+        2 => y*2,
+        4 => y*3,
+        _ => 11
+    }
+}