Some instructions emitted by LLVM (like movaps) expect 16-byte
alignment, while the allocator assumed that 8-byte alignment is good
enough.
TODO: this issue came to light with LLVM optimizing a complex128 store
to the movaps instruction, which must be aligned. It looks like this
means that the <2 x double> IR type is actually 16-byte aligned instead
of 8-byte like a double. If this is the case, the alignment of complex
numbers needs to be updated in the whole compiler.
This commit does two things:
* It adds support for the GOOS and GOARCH environment variables. They
fall back to runtime.GO* only when not available.
* It adds support for 3 new architectures: 386, arm, and arm64. For
now, this is Linux-only.
Make sure every to-be-implemented GC can use the same interface. As a
result, a 1MB chunk of RAM is allocated on Unix systems on init instead
of allocating on demand.
* Use 64-bit integers on 64-bit platforms, just like gc and gccgo:
https://golang.org/doc/go1.1#int
* Do not use a separate length type. Instead, use uintptr everywhere a
length is expected.
