---

yaml
---
r: 80582
b: refs/heads/auto
c: b2eb1c0
h: refs/heads/master
v: v3

Author: thestinger

[refs]

@@ -13,7 +13,7 @@ refs/heads/try3: 9387340aab40a73e8424c48fd42f0c521a4875c0
 refs/tags/release-0.3.1: 495bae036dfe5ec6ceafd3312b4dca48741e845b
 refs/tags/release-0.4: e828ea2080499553b97dfe33b3f4d472b4562ad7
 refs/tags/release-0.5: 7e3bcfbf21278251ee936ad53e92e9b719702d73
-refs/heads/auto: 3c31cf25b18a1300d723e7a3b155810b23d4b472
+refs/heads/auto: b2eb1c01a45cbb7bfc40f24073b60de61e3fad47
 refs/heads/servo: af82457af293e2a842ba6b7759b70288da276167
 refs/tags/release-0.6: b4ebcfa1812664df5e142f0134a5faea3918544c
 refs/tags/0.1: b19db808c2793fe2976759b85a355c3ad8c8b336

branches/auto/src/librustc/middle/trans/base.rs

@@ -248,6 +248,17 @@ pub fn decl_rust_fn(ccx: &mut CrateContext, inputs: &[ty::t], output: ty::t,
         }
     }
 
+    // The out pointer will never alias with any other pointers, as the object only exists at a
+    // language level after the call. It can also be tagged with SRet to indicate that it is
+    // guaranteed to point to a usable block of memory for the type.
+    if uses_outptr {
+        unsafe {
+            let outptr = llvm::LLVMGetParam(llfn, 0);
+            llvm::LLVMAddAttribute(outptr, lib::llvm::StructRetAttribute as c_uint);
+            llvm::LLVMAddAttribute(outptr, lib::llvm::NoAliasAttribute as c_uint);
+        }
+    }
+
     llfn
 }
 

branches/auto/src/librustc/middle/trans/callee.rs

@@ -20,7 +20,7 @@ use std::vec;
 
 use back::abi;
 use driver::session;
-use lib::llvm::ValueRef;
+use lib::llvm::{ValueRef, NoAliasAttribute, StructRetAttribute};
 use lib::llvm::llvm;
 use metadata::csearch;
 use middle::trans::base;
@@ -707,7 +707,21 @@ pub fn trans_call_inner(in_cx: @mut Block,
             }
 
             // Invoke the actual rust fn and update bcx/llresult.
-            let (llret, b) = base::invoke(bcx, llfn, llargs, []);
+            let mut attrs = ~[];
+            if type_of::return_uses_outptr(in_cx.tcx(), ret_ty) {
+                attrs.push((1, StructRetAttribute));
+            }
+
+            match ty::get(ret_ty).sty {
+                // `~` pointer return values never alias because ownership is transferred
+                ty::ty_uniq(*) |
+                ty::ty_evec(_, ty::vstore_uniq) => {
+                    attrs.push((0, NoAliasAttribute));
+                }
+                _ => ()
+            }
+
+            let (llret, b) = base::invoke(bcx, llfn, llargs, attrs);
             bcx = b;
             llresult = llret;
 

branches/auto/src/librustc/middle/trans/foreign.rs

@@ -497,7 +497,7 @@ pub fn trans_rust_fn_with_foreign_abi(ccx: @mut CrateContext,
             // Rust expects to use an outpointer. If the foreign fn
             // also uses an outpointer, we can reuse it, but the types
             // may vary, so cast first to the Rust type. If the
-            // foriegn fn does NOT use an outpointer, we will have to
+            // foreign fn does NOT use an outpointer, we will have to
             // alloca some scratch space on the stack.
             match foreign_outptr {
                 Some(llforeign_outptr) => {