---

yaml
---
r: 35966
b: refs/heads/try2
c: 7f12cc4
h: refs/heads/master
v: v3

Author: catamorphism

[refs]

@@ -5,7 +5,7 @@ refs/heads/snap-stage3: eb8fd119c65c67f3b1b8268cc7341c22d39b7b61
 refs/heads/try: d324a424d8f84b1eb049b12cf34182bda91b0024
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b
-refs/heads/try2: 47c83f1844d033a2ee12aa05eed30112804f4585
+refs/heads/try2: 7f12cc4e63657155f54fd734c791f66f5f6d9e20
 refs/heads/incoming: d9317a174e434d4c99fc1a37fd7dc0d2f5328d37
 refs/heads/dist-snap: 22efa39382d41b084fde1719df7ae8ce5697d8c9
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596

branches/try2/src/rustc/middle/trans/foreign.rs

@@ -112,9 +112,10 @@ fn classify_ty(ty: TypeRef) -> ~[x86_64_reg_class] {
             Float => 4,
             Double => 8,
             Struct => {
-              do vec::foldl(0, struct_tys(ty)) |s, t| {
-                    s + ty_size(*t)
-                }
+              let size = do vec::foldl(0, struct_tys(ty)) |s, t| {
+                  align(s, *t) + ty_size(*t)
+              };
+              align(size, ty)
             }
             Array => {
               let len = llvm::LLVMGetArrayLength(ty) as uint;

branches/try2/src/test/run-pass/issue-3656.rs

@@ -0,0 +1,20 @@
+// Issue #3656
+// Incorrect struct size computation in the FFI, because of not taking
+// the alignment of elements into account.
+
+use libc::*;
+
+struct KEYGEN {
+    hash_algorithm: [c_uint]/2,
+    count: uint32_t,
+    salt: *c_void,
+    salt_size: uint32_t,
+}
+
+extern {
+    // Bogus signature, just need to test if it compiles.
+    pub fn malloc(++data: KEYGEN);
+}
+
+fn main() {
+}