Merge branch 'master' into drop

Author: mjbshaw

Diff for: RELEASES.md

@@ -1,3 +1,16 @@
+Version 1.29.1 (2018-09-25)
+===========================
+
+Security Notes
+--------------
+
+- The standard library's `str::repeat` function contained an out of bounds write
+  caused by an integer overflow. This has been fixed by deterministically
+  panicking when an overflow happens.
+
+  Thank you to Scott McMurray for responsibily disclosing this vulnerability to
+  us.
+
 Version 1.29.0 (2018-09-13)
 ==========================
 

Diff for: src/Cargo.lock

@@ -344,6 +344,7 @@ dependencies = [
  "semver 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.75 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 1.0.75 (registry+https://github.com/rust-lang/crates.io-index)",
+ "smallvec 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "toml 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-normalization 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 1.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2372,6 +2373,7 @@ dependencies = [
  "rls-span 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
  "rustc-serialize 0.3.24 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc_codegen_utils 0.0.0",
  "rustc_data_structures 0.0.0",
  "rustc_target 0.0.0",
  "rustc_typeck 0.0.0",

Diff for: src/doc/unstable-book/src/compiler-flags/emit-stack-sizes.md

@@ -0,0 +1,167 @@
+# `emit-stack-sizes`
+
+The tracking issue for this feature is: [#54192]
+
+[#54192]: https://github.com/rust-lang/rust/issues/54192
+
+------------------------
+
+The rustc flag `-Z emit-stack-sizes` makes LLVM emit stack size metadata.
+
+> **NOTE**: This LLVM feature only supports the ELF object format as of LLVM
+> 8.0. Using this flag with targets that use other object formats (e.g. macOS
+> and Windows) will result in it being ignored.
+
+Consider this crate:
+
+```
+#![crate_type = "lib"]
+
+use std::ptr;
+
+pub fn foo() {
+    // this function doesn't use the stack
+}
+
+pub fn bar() {
+    let xs = [0u32; 2];
+
+    // force LLVM to allocate `xs` on the stack
+    unsafe { ptr::read_volatile(&xs.as_ptr()); }
+}
+```
+
+Using the `-Z emit-stack-sizes` flag produces extra linker sections in the
+output *object file*.
+
+``` console
+$ rustc -C opt-level=3 --emit=obj foo.rs
+
+$ size -A foo.o
+foo.o  :
+section                                 size   addr
+.text                                      0      0
+.text._ZN3foo3foo17he211d7b4a3a0c16eE      1      0
+.text._ZN3foo3bar17h1acb594305f70c2eE     22      0
+.note.GNU-stack                            0      0
+.eh_frame                                 72      0
+Total                                     95
+
+$ rustc -C opt-level=3 --emit=obj -Z emit-stack-sizes foo.rs
+
+$ size -A foo.o
+foo.o  :
+section                                 size   addr
+.text                                      0      0
+.text._ZN3foo3foo17he211d7b4a3a0c16eE      1      0
+.stack_sizes                               9      0
+.text._ZN3foo3bar17h1acb594305f70c2eE     22      0
+.stack_sizes                               9      0
+.note.GNU-stack                            0      0
+.eh_frame                                 72      0
+Total                                    113
+```
+
+As of LLVM 7.0 the data will be written into a section named `.stack_sizes` and
+the format is "an array of pairs of function symbol values (pointer size) and
+stack sizes (unsigned LEB128)".
+
+``` console
+$ objdump -d foo.o
+
+foo.o:     file format elf64-x86-64
+
+Disassembly of section .text._ZN3foo3foo17he211d7b4a3a0c16eE:
+
+0000000000000000 <_ZN3foo3foo17he211d7b4a3a0c16eE>:
+   0:   c3                      retq
+
+Disassembly of section .text._ZN3foo3bar17h1acb594305f70c2eE:
+
+0000000000000000 <_ZN3foo3bar17h1acb594305f70c2eE>:
+   0:   48 83 ec 10             sub    $0x10,%rsp
+   4:   48 8d 44 24 08          lea    0x8(%rsp),%rax
+   9:   48 89 04 24             mov    %rax,(%rsp)
+   d:   48 8b 04 24             mov    (%rsp),%rax
+  11:   48 83 c4 10             add    $0x10,%rsp
+  15:   c3                      retq
+
+$ objdump -s -j .stack_sizes foo.o
+
+foo.o:     file format elf64-x86-64
+
+Contents of section .stack_sizes:
+ 0000 00000000 00000000 00                 .........
+Contents of section .stack_sizes:
+ 0000 00000000 00000000 10                 .........
+```
+
+It's important to note that linkers will discard this linker section by default.
+To preserve the section you can use a linker script like the one shown below.
+
+``` text
+/* file: keep-stack-sizes.x */
+SECTIONS
+{
+  /* `INFO` makes the section not allocatable so it won't be loaded into memory */
+  .stack_sizes (INFO) :
+  {
+    KEEP(*(.stack_sizes));
+  }
+}
+```
+
+The linker script must be passed to the linker using a rustc flag like `-C
+link-arg`.
+
+```
+// file: src/main.rs
+use std::ptr;
+
+#[inline(never)]
+fn main() {
+    let xs = [0u32; 2];
+
+    // force LLVM to allocate `xs` on the stack
+    unsafe { ptr::read_volatile(&xs.as_ptr()); }
+}
+```
+
+``` console
+$ RUSTFLAGS="-Z emit-stack-sizes" cargo build --release
+
+$ size -A target/release/hello | grep stack_sizes || echo section was not found
+section was not found
+
+$ RUSTFLAGS="-Z emit-stack-sizes" cargo rustc --release -- \
+    -C link-arg=-Wl,-Tkeep-stack-sizes.x \
+    -C link-arg=-N
+
+$ size -A target/release/hello | grep stack_sizes
+.stack_sizes                               90   176272
+
+$ # non-allocatable section (flags don't contain the "A" (alloc) flag)
+$ readelf -S target/release/hello
+Section Headers:
+  [Nr]   Name              Type             Address           Offset
+       Size              EntSize            Flags  Link  Info  Align
+(..)
+  [1031] .stack_sizes      PROGBITS         000000000002b090  0002b0f0
+       000000000000005a  0000000000000000   L       5     0     1
+
+$ objdump -s -j .stack_sizes target/release/hello
+
+target/release/hello:     file format elf64-x86-64
+
+Contents of section .stack_sizes:
+ 2b090 c0040000 00000000 08f00400 00000000  ................
+ 2b0a0 00080005 00000000 00000810 05000000  ................
+ 2b0b0 00000000 20050000 00000000 10400500  .... ........@..
+ 2b0c0 00000000 00087005 00000000 00000080  ......p.........
+ 2b0d0 05000000 00000000 90050000 00000000  ................
+ 2b0e0 00a00500 00000000 0000               ..........
+```
+
+> Author note: I'm not entirely sure why, in *this* case, `-N` is required in
+> addition to `-Tkeep-stack-sizes.x`. For example, it's not required when
+> producing statically linked files for the ARM Cortex-M architecture.

Diff for: src/etc/gdb_rust_pretty_printing.py

@@ -322,11 +322,8 @@ def to_string(self):
     def children(self):
         (length, data_ptr) = \
             rustpp.extract_length_and_ptr_from_std_btreeset(self.__val)
-        leaf_node = GdbValue(data_ptr.get_wrapped_value().dereference())
-        maybe_uninit_keys = leaf_node.get_child_at_index(3)
-        manually_drop_keys = maybe_uninit_keys.get_child_at_index(1)
-        keys = manually_drop_keys.get_child_at_index(0)
-        gdb_ptr = keys.get_wrapped_value()
+        val = GdbValue(data_ptr.get_wrapped_value().dereference()).get_child_at_index(3)
+        gdb_ptr = val.get_wrapped_value()
         for index in xrange(length):
             yield (str(index), gdb_ptr[index])
 
@@ -348,14 +345,9 @@ def to_string(self):
     def children(self):
         (length, data_ptr) = \
             rustpp.extract_length_and_ptr_from_std_btreemap(self.__val)
-        leaf_node = GdbValue(data_ptr.get_wrapped_value().dereference())
-        maybe_uninit_keys = leaf_node.get_child_at_index(3)
-        manually_drop_keys = maybe_uninit_keys.get_child_at_index(1)
-        keys = manually_drop_keys.get_child_at_index(0)
+        keys = GdbValue(data_ptr.get_wrapped_value().dereference()).get_child_at_index(3)
         keys_ptr = keys.get_wrapped_value()
-        maybe_uninit_vals = leaf_node.get_child_at_index(4)
-        manually_drop_vals = maybe_uninit_vals.get_child_at_index(1)
-        vals = manually_drop_vals.get_child_at_index(0)
+        vals = GdbValue(data_ptr.get_wrapped_value().dereference()).get_child_at_index(4)
         vals_ptr = vals.get_wrapped_value()
         for index in xrange(length):
             yield (str(index), keys_ptr[index])

Diff for: src/liballoc/collections/btree/node.rs

@@ -42,7 +42,7 @@
 //   This implies that even an empty internal node has at least one edge.
 
 use core::marker::PhantomData;
-use core::mem::{self, MaybeUninit};
+use core::mem;
 use core::ptr::{self, Unique, NonNull};
 use core::slice;
 
@@ -73,7 +73,7 @@ struct LeafNode<K, V> {
     /// This node's index into the parent node's `edges` array.
     /// `*node.parent.edges[node.parent_idx]` should be the same thing as `node`.
     /// This is only guaranteed to be initialized when `parent` is nonnull.
-    parent_idx: MaybeUninit<u16>,
+    parent_idx: u16,
 
     /// The number of keys and values this node stores.
     ///
@@ -83,8 +83,8 @@ struct LeafNode<K, V> {
 
     /// The arrays storing the actual data of the node. Only the first `len` elements of each
     /// array are initialized and valid.
-    keys: MaybeUninit<[K; CAPACITY]>,
-    vals: MaybeUninit<[V; CAPACITY]>,
+    keys: [K; CAPACITY],
+    vals: [V; CAPACITY],
 }
 
 impl<K, V> LeafNode<K, V> {
@@ -94,10 +94,10 @@ impl<K, V> LeafNode<K, V> {
         LeafNode {
             // As a general policy, we leave fields uninitialized if they can be, as this should
             // be both slightly faster and easier to track in Valgrind.
-            keys: MaybeUninit::uninitialized(),
-            vals: MaybeUninit::uninitialized(),
+            keys: mem::uninitialized(),
+            vals: mem::uninitialized(),
             parent: ptr::null(),
-            parent_idx: MaybeUninit::uninitialized(),
+            parent_idx: mem::uninitialized(),
             len: 0
         }
     }
@@ -115,10 +115,10 @@ unsafe impl Sync for LeafNode<(), ()> {}
 // ever take a pointer past the first key.
 static EMPTY_ROOT_NODE: LeafNode<(), ()> = LeafNode {
     parent: ptr::null(),
-    parent_idx: MaybeUninit::uninitialized(),
+    parent_idx: 0,
     len: 0,
-    keys: MaybeUninit::uninitialized(),
-    vals: MaybeUninit::uninitialized(),
+    keys: [(); CAPACITY],
+    vals: [(); CAPACITY],
 };
 
 /// The underlying representation of internal nodes. As with `LeafNode`s, these should be hidden
@@ -430,7 +430,7 @@ impl<BorrowType, K, V, Type> NodeRef<BorrowType, K, V, Type> {
                     root: self.root,
                     _marker: PhantomData
                 },
-                idx: unsafe { usize::from(*self.as_leaf().parent_idx.get_ref()) },
+                idx: self.as_leaf().parent_idx as usize,
                 _marker: PhantomData
             })
         } else {
@@ -567,7 +567,7 @@ impl<'a, K: 'a, V: 'a, Type> NodeRef<marker::Immut<'a>, K, V, Type> {
             // the node, which is allowed by LLVM.
             unsafe {
                 slice::from_raw_parts(
-                    self.as_leaf().keys.as_ptr() as *const K,
+                    self.as_leaf().keys.as_ptr(),
                     self.len()
                 )
             }
@@ -578,7 +578,7 @@ impl<'a, K: 'a, V: 'a, Type> NodeRef<marker::Immut<'a>, K, V, Type> {
         debug_assert!(!self.is_shared_root());
         unsafe {
             slice::from_raw_parts(
-                self.as_leaf().vals.as_ptr() as *const V,
+                self.as_leaf().vals.as_ptr(),
                 self.len()
             )
         }
@@ -605,7 +605,7 @@ impl<'a, K: 'a, V: 'a, Type> NodeRef<marker::Mut<'a>, K, V, Type> {
         } else {
             unsafe {
                 slice::from_raw_parts_mut(
-                    self.as_leaf_mut().keys.get_mut() as *mut [K] as *mut K,
+                    &mut self.as_leaf_mut().keys as *mut [K] as *mut K,
                     self.len()
                 )
             }
@@ -616,7 +616,7 @@ impl<'a, K: 'a, V: 'a, Type> NodeRef<marker::Mut<'a>, K, V, Type> {
         debug_assert!(!self.is_shared_root());
         unsafe {
             slice::from_raw_parts_mut(
-                self.as_leaf_mut().vals.get_mut() as *mut [V] as *mut V,
+                &mut self.as_leaf_mut().vals as *mut [V] as *mut V,
                 self.len()
             )
         }
@@ -1013,7 +1013,7 @@ impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>, marker::
         let ptr = self.node.as_internal_mut() as *mut _;
         let mut child = self.descend();
         child.as_leaf_mut().parent = ptr;
-        child.as_leaf_mut().parent_idx.set(idx);
+        child.as_leaf_mut().parent_idx = idx;
     }
 
     /// Unsafely asserts to the compiler some static information about whether the underlying
@@ -1152,12 +1152,12 @@ impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::KV>
 
             ptr::copy_nonoverlapping(
                 self.node.keys().as_ptr().add(self.idx + 1),
-                new_node.keys.as_mut_ptr() as *mut K,
+                new_node.keys.as_mut_ptr(),
                 new_len
             );
             ptr::copy_nonoverlapping(
                 self.node.vals().as_ptr().add(self.idx + 1),
-                new_node.vals.as_mut_ptr() as *mut V,
+                new_node.vals.as_mut_ptr(),
                 new_len
             );
 
@@ -1210,12 +1210,12 @@ impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>, marker::
 
             ptr::copy_nonoverlapping(
                 self.node.keys().as_ptr().add(self.idx + 1),
-                new_node.data.keys.as_mut_ptr() as *mut K,
+                new_node.data.keys.as_mut_ptr(),
                 new_len
             );
             ptr::copy_nonoverlapping(
                 self.node.vals().as_ptr().add(self.idx + 1),
-                new_node.data.vals.as_mut_ptr() as *mut V,
+                new_node.data.vals.as_mut_ptr(),
                 new_len
             );
             ptr::copy_nonoverlapping(

Diff for: src/liballoc/lib.rs

@@ -120,7 +120,6 @@
 #![feature(rustc_const_unstable)]
 #![feature(const_vec_new)]
 #![feature(slice_partition_dedup)]
-#![feature(maybe_uninit)]
 
 // Allow testing this library