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std: allocator interface sets freed memory to undefined

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daurnimator 2020-01-11 00:09:29 +11:00
parent 65013d8599
commit 5cc4932461
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1 changed files with 3 additions and 0 deletions
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lib/std/mem.zig
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@ -175,6 +175,7 @@ pub const Allocator = struct {
const old_byte_slice = @sliceToBytes(old_mem);
const byte_count = math.mul(usize, @sizeOf(T), new_n) catch return Error.OutOfMemory;
// Note: can't set shrunk memory to undefined as memory shouldn't be modified on realloc failure
const byte_slice = try self.reallocFn(self, old_byte_slice, Slice.alignment, byte_count, new_alignment);
assert(byte_slice.len == byte_count);
if (new_n > old_mem.len) {
@ -221,6 +222,7 @@ pub const Allocator = struct {
const byte_count = @sizeOf(T) * new_n;
const old_byte_slice = @sliceToBytes(old_mem);
@memset(old_byte_slice.ptr + byte_count, undefined, old_byte_slice.len - byte_count);
const byte_slice = self.shrinkFn(self, old_byte_slice, Slice.alignment, byte_count, new_alignment);
assert(byte_slice.len == byte_count);
return @bytesToSlice(T, @alignCast(new_alignment, byte_slice));
@ -234,6 +236,7 @@ pub const Allocator = struct {
const bytes_len = bytes.len + @boolToInt(Slice.sentinel != null);
if (bytes_len == 0) return;
const non_const_ptr = @intToPtr([*]u8, @ptrToInt(bytes.ptr));
@memset(non_const_ptr, undefined, bytes_len);
const shrink_result = self.shrinkFn(self, non_const_ptr[0..bytes_len], Slice.alignment, 0, 1);
assert(shrink_result.len == 0);
}