elfmalloc: Bubble up OOM errors, remove unnecessary internal code

- Make many internal methods return Option<T> rather than T and
  return None on OOM
- Remove CoarseAllocator::backing_memory and replace it with
  page_size (which was all the former method was ever being used
  for)

Author: joshlf

elfmalloc/CHANGELOG.md

@@ -1,4 +1,4 @@
-<!-- Copyright 2017 the authors. See the 'Copyright and license' section of the
+<!-- Copyright 2017-2018 the authors. See the 'Copyright and license' section of the
 README.md file at the top-level directory of this repository.
 
 Licensed under the Apache License, Version 2.0 (the LICENSE-APACHE file) or
@@ -25,6 +25,10 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
   `MagazineCache`
 - Added `c-api` feature to optimize for the C malloc API
 
+### Changed
+- Changed error reporting so that more OOM errors are bubbled up and result
+  in top-level errors rather than panics
+
 ### Fixed
 - Fixed a bug preventing non-nightly builds from compiling
 - Fixed an integer multiplication overflow bug

elfmalloc/Cargo.toml

@@ -1,4 +1,4 @@
-# Copyright 2017 the authors. See the 'Copyright and license' section of the
+# Copyright 2017-2018 the authors. See the 'Copyright and license' section of the
 # README.md file at the top-level directory of this repository.
 #
 # Licensed under the Apache License, Version 2.0 (the LICENSE-APACHE file) or
@@ -49,7 +49,7 @@ alloc-fmt = { path = "../alloc-fmt" }
 alloc-tls = { path = "../alloc-tls" }
 bagpipe = { path = "../bagpipe" }
 bsalloc = "0.1.0"
-lazy_static = "1.0.0"
+lazy_static = { version = "1.0.0", features = ["spin_no_std"] }
 libc = "0.2"
 log = "0.3.8"
 malloc-bind = { path = "../malloc-bind" }

elfmalloc/src/alloc_impl.rs

@@ -1,4 +1,4 @@
-// Copyright 2017 the authors. See the 'Copyright and license' section of the
+// Copyright 2017-2018 the authors. See the 'Copyright and license' section of the
 // README.md file at the top-level directory of this repository.
 //
 // Licensed under the Apache License, Version 2.0 (the LICENSE-APACHE file) or
@@ -25,6 +25,8 @@ use super::general::global;
 use std::mem;
 #[cfg(feature = "c-api")]
 use std::intrinsics::unlikely;
+#[cfg(feature = "c-api")]
+use std::ptr;
 
 #[cfg(feature = "c-api")]
 use self::libc::{size_t, c_void};
@@ -39,25 +41,25 @@ unsafe impl<'a> Alloc for &'a ElfMallocGlobal {
         // two up to 1MiB are aligned to their size. Past that size, only page-alignment is
         // guaranteed.
         if l.size().is_power_of_two() || l.align() <= mem::size_of::<usize>() {
-            Ok(global::alloc(l.size()))
+            global::alloc(l.size())
         } else {
-            Ok(global::alloc(l.size().next_power_of_two()))
-        }
+            global::alloc(l.size().next_power_of_two())
+        }.ok_or(AllocErr::Exhausted { request: l })
     }
 
     unsafe fn dealloc(&mut self, p: *mut u8, _l: Layout) {
         global::free(p);
     }
 
     unsafe fn realloc(&mut self, p: *mut u8, _l1: Layout, l2: Layout) -> Result<*mut u8, AllocErr> {
-        Ok(global::aligned_realloc(p, l2.size(), l2.align()))
+        global::aligned_realloc(p, l2.size(), l2.align()).ok_or(AllocErr::Exhausted { request: l2 })
     }
 }
 
 #[cfg(feature = "c-api")]
 unsafe impl Malloc for ElfMallocGlobal {
     unsafe fn c_malloc(&self, size: size_t) -> *mut c_void {
-        let p = global::alloc(size as usize) as *mut c_void;
+        let p = global::alloc(size as usize).unwrap_or(ptr::null_mut()) as *mut c_void;
         alloc_debug_assert_eq!((p as usize) % MIN_ALIGN,
                          0,
                          "object does not have the required alignment of {}: {:?}",
@@ -82,7 +84,7 @@ unsafe impl Malloc for ElfMallocGlobal {
                          "object does not have the required alignment of {}: {:?}",
                          MIN_ALIGN,
                          p);
-        global::realloc(p as *mut u8, new_size as usize) as *mut c_void
+        global::realloc(p as *mut u8, new_size as usize).unwrap_or(ptr::null_mut()) as *mut c_void
     }
 }
 

elfmalloc/src/bin/bench.rs

@@ -1,4 +1,4 @@
-// Copyright 2017 the authors. See the 'Copyright and license' section of the
+// Copyright 2017-2018 the authors. See the 'Copyright and license' section of the
 // README.md file at the top-level directory of this repository.
 //
 // Licensed under the Apache License, Version 2.0 (the LICENSE-APACHE file) or
@@ -101,11 +101,12 @@ unsafe impl<T> Send for ElfClone<T> {}
 impl<T: 'static> AllocLike for ElfClone<T> {
     type Item = T;
     fn create() -> Self {
-        ElfClone(DynamicAllocator::new(), marker::PhantomData)
+        ElfClone(DynamicAllocator::new().unwrap(), marker::PhantomData)
     }
 
     unsafe fn allocate(&mut self) -> *mut T {
-        self.0.alloc(mem::size_of::<T>()) as *mut T
+        // TODO: Do something other than unwrap?
+        self.0.alloc(mem::size_of::<T>()).unwrap() as *mut T
     }
 
     unsafe fn deallocate(&mut self, item: *mut T) {