From 990db3c35a798a6e51dbbbc1696f3fe78c7a0faf Mon Sep 17 00:00:00 2001
From: Andrew Kelley <superjoe30@gmail.com>
Date: Sun, 10 Dec 2017 15:03:57 -0500
Subject: [PATCH 1/2] rename @EnumTagType to @TagType in type names

---
 src/analyze.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/analyze.cpp b/src/analyze.cpp
index 431b64f984..1d5d5e4790 100644
--- a/src/analyze.cpp
+++ b/src/analyze.cpp
@@ -2227,7 +2227,7 @@ static void resolve_union_zero_bits(CodeGen *g, TypeTableEntry *union_type) {
 
         tag_type = new_type_table_entry(TypeTableEntryIdEnum);
         buf_resize(&tag_type->name, 0);
-        buf_appendf(&tag_type->name, "@EnumTagType(%s)", buf_ptr(&union_type->name));
+        buf_appendf(&tag_type->name, "@TagType(%s)", buf_ptr(&union_type->name));
         tag_type->is_copyable = true;
         tag_type->type_ref = tag_int_type->type_ref;
         tag_type->zero_bits = tag_int_type->zero_bits;

From 22dc713a2f6b19ccba31434cfa2bc619c1a2c170 Mon Sep 17 00:00:00 2001
From: Andrew Kelley <superjoe30@gmail.com>
Date: Sun, 10 Dec 2017 15:38:05 -0500
Subject: [PATCH 2/2] mem.Allocator initializes bytes to undefined

---
 std/mem.zig | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/std/mem.zig b/std/mem.zig
index e99675d248..2e6bd6ec85 100644
--- a/std/mem.zig
+++ b/std/mem.zig
@@ -8,6 +8,7 @@ pub const Cmp = math.Cmp;
 pub const Allocator = struct {
     /// Allocate byte_count bytes and return them in a slice, with the
     /// slice's pointer aligned at least to alignment bytes.
+    /// The returned newly allocated memory is undefined.
     allocFn: fn (self: &Allocator, byte_count: usize, alignment: u29) -> %[]u8,
 
     /// If `new_byte_count > old_mem.len`:
@@ -17,6 +18,8 @@ pub const Allocator = struct {
     /// If `new_byte_count <= old_mem.len`:
     /// * this function must return successfully. 
     /// * alignment <= alignment of old_mem.ptr
+    ///
+    /// The returned newly allocated memory is undefined.
     reallocFn: fn (self: &Allocator, old_mem: []u8, new_byte_count: usize, alignment: u29) -> %[]u8,
 
     /// Guaranteed: `old_mem.len` is the same as what was returned from `allocFn` or `reallocFn`
@@ -40,6 +43,10 @@ pub const Allocator = struct {
     {
         const byte_count = %return math.mul(usize, @sizeOf(T), n);
         const byte_slice = %return self.allocFn(self, byte_count, alignment);
+        // This loop should get optimized out in ReleaseFast mode
+        for (byte_slice) |*byte| {
+            *byte = undefined;
+        }
         return ([]align(alignment) T)(@alignCast(alignment, byte_slice));
     }
 
@@ -54,8 +61,13 @@ pub const Allocator = struct {
             return self.alloc(T, n);
         }
 
+        const old_byte_slice = ([]u8)(old_mem);
         const byte_count = %return math.mul(usize, @sizeOf(T), n);
-        const byte_slice = %return self.reallocFn(self, ([]u8)(old_mem), byte_count, alignment);
+        const byte_slice = %return self.reallocFn(self, old_byte_slice, byte_count, alignment);
+        // This loop should get optimized out in ReleaseFast mode
+        for (byte_slice[old_byte_slice.len..]) |*byte| {
+            *byte = undefined;
+        }
         return ([]T)(@alignCast(alignment, byte_slice));
     }