Merge pull request #32 from fitzgen/arbitrary-alignment

Arbitrary alignment

Author: fitzgen

.travis.yml

@@ -4,15 +4,6 @@ cache: cargo
 rust:
   - nightly
 
-# For `binaryen`.
-addons:
-  apt:
-    sources:
-      - 'ubuntu-toolchain-r-test'
-    packages:
-      - 'cmake'
-      - 'g++-5'
-
 env:
   matrix:
     - SCRIPT="./check.sh"
@@ -23,9 +14,6 @@ before_script:
   - rustup target add wasm32-unknown-unknown
   - which wasm-gc || cargo install --git https://github.com/alexcrichton/wasm-gc
   - which cargo-readme || cargo install cargo-readme
-  - test -d binaryen || git clone https://github.com/WebAssembly/binaryen.git
-  - export PATH="$PATH:$(pwd)/binaryen/bin"
-  - which wasm-opt || (cd binaryen && cmake . && make -j4 && cd -)
 
 script:
   - "$SCRIPT"

README.md

@@ -115,8 +115,6 @@ static ALLOC: wee_alloc::WeeAlloc = wee_alloc::WeeAlloc::INIT;
 - `wee_alloc` imposes two words of overhead on each allocation for maintaining
   its internal free lists.
 
-- The maximum alignment supported is word alignment.
-
 - Deallocation is an *O(1)* operation.
 
 - `wee_alloc` will never return freed pages to the WebAssembly engine /

build.sh

@@ -22,17 +22,23 @@ cargo build --release                         --target wasm32-unknown-unknown
 
 wasm-gc ../target/wasm32-unknown-unknown/release/wee_alloc_example.wasm \
         ../target/wasm32-unknown-unknown/release/wee_alloc_example.gc.wasm
-wasm-opt -Oz \
-         ../target/wasm32-unknown-unknown/release/wee_alloc_example.gc.wasm \
-         -o ../target/wasm32-unknown-unknown/release/wee_alloc_example.gc.opt.wasm
+
+if which wasm-opt; then
+    wasm-opt -Oz \
+             ../target/wasm32-unknown-unknown/release/wee_alloc_example.gc.wasm \
+             -o ../target/wasm32-unknown-unknown/release/wee_alloc_example.gc.opt.wasm
+fi
 
 cargo build --release --features size_classes --target wasm32-unknown-unknown
 
 wasm-gc ../target/wasm32-unknown-unknown/release/wee_alloc_example.wasm \
         ../target/wasm32-unknown-unknown/release/wee_alloc_example.size_classes.gc.wasm
-wasm-opt -Oz \
-         ../target/wasm32-unknown-unknown/release/wee_alloc_example.size_classes.gc.wasm \
-         -o ../target/wasm32-unknown-unknown/release/wee_alloc_example.size_classes.gc.opt.wasm
+
+if which wasm-opt; then
+    wasm-opt -Oz \
+             ../target/wasm32-unknown-unknown/release/wee_alloc_example.size_classes.gc.wasm \
+             -o ../target/wasm32-unknown-unknown/release/wee_alloc_example.size_classes.gc.opt.wasm
+fi
 
 wc -c ../target/wasm32-unknown-unknown/release/*.gc.opt.wasm
 

test/src/lib.rs

@@ -1,6 +1,7 @@
 #![feature(alloc, allocator_api)]
 
 extern crate alloc;
+#[macro_use]
 extern crate quickcheck;
 extern crate rand;
 extern crate wee_alloc;
@@ -278,6 +279,20 @@ fn multi_threaded_quickchecks() {
     );
 }
 
+#[cfg(test)]
+static ALIGNS: [usize; 10] = [1, 2, 4, 8, 16, 32, 64, 128, 256, 512];
+
+quickcheck! {
+    fn single_allocation_with_size_and_align(size: usize, align: usize) -> () {
+        let size = size % 65536;
+        let align = ALIGNS[align % ALIGNS.len()];
+
+        let mut w = &wee_alloc::WeeAlloc::INIT;
+        let layout = alloc::heap::Layout::from_size_align(size, align).unwrap();
+        let _ = unsafe { w.alloc(layout) };
+    }
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 
 #[test]

test/tests/global.rs

@@ -33,3 +33,26 @@ fn strings() {
 fn threads() {
     assert!(thread::spawn(|| panic!()).join().is_err());
 }
+
+#[test]
+fn test_larger_than_word_alignment() {
+    use std::mem;
+
+    // Align to 32 bytes.
+    #[repr(align(32))]
+    struct Align32(u8);
+
+    assert_eq!(mem::align_of::<Align32>(), 32);
+
+    for _ in 0..100 {
+        let b = Box::new(Align32(42));
+
+        let p = Box::into_raw(b);
+        assert_eq!(p as usize % 32, 0, "{:p} should be aligned to 32", p);
+
+        unsafe {
+            let b = Box::from_raw(p);
+            assert_eq!(b.0, 42);
+        }
+    }
+}