---

yaml
---
r: 151315
b: refs/heads/try2
c: d943b0f
h: refs/heads/master
i:
  151313: f7b1e22
  151311: 9171acb
v: v3

Author: bors

[refs]

@@ -5,7 +5,7 @@ refs/heads/snap-stage3: 78a7676898d9f80ab540c6df5d4c9ce35bb50463
 refs/heads/try: 519addf6277dbafccbb4159db4b710c37eaa2ec5
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b
-refs/heads/try2: 055cbdeee07cae7e8c1a253d4a6f154f140ba821
+refs/heads/try2: d943b0fee8cc0f747eaf2c0f0ae6e7bc35284ca8
 refs/heads/dist-snap: ba4081a5a8573875fed17545846f6f6902c8ba8d
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596
 refs/tags/release-0.3: b5f0d0f648d9a6153664837026ba1be43d3e2503

branches/try2/src/librustc/middle/trans/adt.rs

@@ -779,6 +779,26 @@ pub fn trans_const(ccx: &CrateContext, r: &Repr, discr: Disr,
     }
 }
 
+/**
+ * Compute struct field offsets relative to struct begin.
+ */
+fn compute_struct_field_offsets(ccx: &CrateContext, st: &Struct) -> Vec<u64> {
+    let mut offsets = vec!();
+
+    let mut offset = 0;
+    for &ty in st.fields.iter() {
+        let llty = type_of::sizing_type_of(ccx, ty);
+        if !st.packed {
+            let type_align = machine::llalign_of_min(ccx, llty) as u64;
+            offset = roundup(offset, type_align);
+        }
+        offsets.push(offset);
+        offset += machine::llsize_of_alloc(ccx, llty) as u64;
+    }
+    assert_eq!(st.fields.len(), offsets.len());
+    offsets
+}
+
 /**
  * Building structs is a little complicated, because we might need to
  * insert padding if a field's value is less aligned than its type.
@@ -793,26 +813,32 @@ fn build_const_struct(ccx: &CrateContext, st: &Struct, vals: &[ValueRef])
     -> Vec<ValueRef> {
     assert_eq!(vals.len(), st.fields.len());
 
+    let target_offsets = compute_struct_field_offsets(ccx, st);
+
+    // offset of current value
     let mut offset = 0;
     let mut cfields = Vec::new();
-    for (i, &ty) in st.fields.iter().enumerate() {
-        let llty = type_of::sizing_type_of(ccx, ty);
-        let type_align = machine::llalign_of_min(ccx, llty)
-            /*bad*/as u64;
-        let val_align = machine::llalign_of_min(ccx, val_ty(vals[i]))
-            /*bad*/as u64;
-        let target_offset = roundup(offset, type_align);
-        offset = roundup(offset, val_align);
+    for (&val, &target_offset) in vals.iter().zip(target_offsets.iter()) {
+        if !st.packed {
+            let val_align = machine::llalign_of_min(ccx, val_ty(val))
+                /*bad*/as u64;
+            offset = roundup(offset, val_align);
+        }
         if offset != target_offset {
             cfields.push(padding(ccx, target_offset - offset));
             offset = target_offset;
         }
-        assert!(!is_undef(vals[i]));
-        cfields.push(vals[i]);
-        offset += machine::llsize_of_alloc(ccx, llty) as u64
+        assert!(!is_undef(val));
+        cfields.push(val);
+        offset += machine::llsize_of_alloc(ccx, val_ty(val)) as u64;
+    }
+
+    assert!(offset <= st.size);
+    if offset != st.size {
+        cfields.push(padding(ccx, st.size - offset));
     }
 
-    return cfields;
+    cfields
 }
 
 fn padding(ccx: &CrateContext, size: u64) -> ValueRef {

branches/try2/src/librustc/middle/trans/base.rs

@@ -186,8 +186,6 @@ fn decl_fn(llmod: ModuleRef, name: &str, cc: lib::llvm::CallConv,
             }
         }
         // `~` pointer return values never alias because ownership is transferred
-        // FIXME #6750 ~Trait cannot be directly marked as
-        // noalias because the actual object pointer is nested.
         ty::ty_uniq(..) // | ty::ty_trait(_, _, ty::UniqTraitStore, _, _)
          => {
             unsafe {
@@ -258,23 +256,25 @@ pub fn decl_rust_fn(ccx: &CrateContext, has_env: bool,
         let llarg = unsafe { llvm::LLVMGetParam(llfn, (offset + i) as c_uint) };
         match ty::get(arg_ty).sty {
             // `~` pointer parameters never alias because ownership is transferred
-            // FIXME #6750 ~Trait cannot be directly marked as
-            // noalias because the actual object pointer is nested.
-            ty::ty_uniq(..) | // ty::ty_trait(_, _, ty::UniqTraitStore, _, _) |
-            ty::ty_closure(~ty::ClosureTy {store: ty::UniqTraitStore, ..}) => {
+            ty::ty_uniq(..) => {
                 unsafe {
                     llvm::LLVMAddAttribute(llarg, lib::llvm::NoAliasAttribute as c_uint);
                 }
-            },
-            // When a reference in an argument has no named lifetime, it's
-            // impossible for that reference to escape this function(ie, be
-            // returned).
+            }
+            // `&mut` pointer parameters never alias other parameters, or mutable global data
+            ty::ty_rptr(_, mt) if mt.mutbl == ast::MutMutable => {
+                unsafe {
+                    llvm::LLVMAddAttribute(llarg, lib::llvm::NoAliasAttribute as c_uint);
+                }
+            }
+            // When a reference in an argument has no named lifetime, it's impossible for that
+            // reference to escape this function (returned or stored beyond the call by a closure).
             ty::ty_rptr(ReLateBound(_, BrAnon(_)), _) => {
                 debug!("marking argument of {} as nocapture because of anonymous lifetime", name);
                 unsafe {
                     llvm::LLVMAddAttribute(llarg, lib::llvm::NoCaptureAttribute as c_uint);
                 }
-            },
+            }
             _ => {
                 // For non-immediate arguments the callee gets its own copy of
                 // the value on the stack, so there are no aliases

branches/try2/src/test/run-pass/trans-tag-static-padding.rs

@@ -0,0 +1,66 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+
+// Issue #13186
+
+// For simplicity of explanations assuming code is compiled for x86_64
+// Linux ABI.
+
+// Size of TestOption<u64> is 16, and alignment of TestOption<u64> is 8.
+// Size of u8 is 1, and alignment of u8 is 1.
+// So size of Request is 24, and alignment of Request must be 8:
+// the maximum alignment of its fields.
+// Last 7 bytes of Request struct are not occupied by any fields.
+
+
+enum TestOption<T> {
+    TestNone,
+    TestSome(T),
+}
+
+pub struct Request {
+    foo: TestOption<u64>,
+    bar: u8,
+}
+
+fn default_instance() -> &'static Request {
+    static instance: Request = Request {
+        // LLVM does not allow to specify alignment of expressions, thus
+        // alignment of `foo` in constant is 1, not 8.
+        foo: TestNone,
+        bar: 17,
+        // Space after last field is not occupied by any data, but it is
+        // reserved to make struct aligned properly. If compiler does
+        // not insert padding after last field when emitting constant,
+        // size of struct may be not equal to size of struct, and
+        // compiler crashes in internal assertion check.
+    };
+    &'static instance
+}
+
+fn non_default_instance() -> &'static Request {
+    static instance: Request = Request {
+        foo: TestSome(0x1020304050607080),
+        bar: 19,
+    };
+    &'static instance
+}
+
+pub fn main() {
+    match default_instance() {
+        &Request { foo: TestNone, bar: 17 } => {},
+        _ => fail!(),
+    };
+    match non_default_instance() {
+        &Request { foo: TestSome(0x1020304050607080), bar: 19 } => {},
+        _ => fail!(),
+    };
+}