These are on the slower side and could be improved. No performance optimizations
yet have been done.
```
Cpu: Intel(R) Core(TM) i5-6500 CPU @ 3.20GHz
```
-- Sha3-256
```
Zig --release-fast
93 Mb/s
Zig --release-safe
99 Mb/s
Zig
4 Mb/s
```
-- Sha3-512
```
Zig --release-fast
49 Mb/s
Zig --release-safe
54 Mb/s
Zig
2 Mb/s
```
Interestingly, release-safe is producing slightly better code than
release-fast.
* error return tracing is disabled in release-fast mode
* add @errorReturnTrace
* zig build API changes build return type from `void` to `%void`
* allow `void`, `noreturn`, and `u8` from main. closes#535
Some performance comparisons to C.
We take the fastest time measurement taken across multiple runs.
The block hashing functions use the same md5/sha1 methods.
```
Cpu: Intel(R) Core(TM) i5-6500 CPU @ 3.20GHz
Gcc: 7.2.1 20171224
Clang: 5.0.1
Zig: 0.1.1.304f6f1d
```
See https://www.nayuki.io/page/fast-md5-hash-implementation-in-x86-assembly:
```
gcc -O2
661 Mb/s
clang -O2
490 Mb/s
zig --release-fast and zig --release-safe
570 Mb/s
zig
50 Mb/s
```
See https://www.nayuki.io/page/fast-sha1-hash-implementation-in-x86-assembly:
```
gcc -O2
588 Mb/s
clang -O2
563 Mb/s
zig --release-fast and zig --release-safe
610 Mb/s
zig
21 Mb/s
```
In short, zig provides pretty useful tools for writing this sort of
code. We are in the lead against clang (which uses the same LLVM
backend) with us being slower only against md5 with GCC.
* better error message for realpath failing
* fix bug in std.io.readFileAllocExtra incorrectly returning
error.EndOfStream
* implement std.os.selfExePath and std.os.selfExeDirPath for windows
Before:
* IR basic blocks are in arbitrary order
* when doing an IR pass, when a block is encountered, code
must look at all the instructions in the old basic block,
determine what blocks are referenced, and queue up those
old basic blocks first.
* This had a bug (See #667)
Now:
* IR basic blocks are required to be in an order that guarantees
they will be referenced by a branch, before any instructions
within are referenced.
ir pass1 is updated to meet this constraint.
* When doing an IR pass, we iterate over old basic blocks
in the order they appear. Blocks which have not been
referenced are discarded.
* After the pass is complete, we must iterate again to look
for old basic blocks which now point to incomplete new
basic blocks, due to comptime code generation.
* This last part can probably be optimized - most of the time
we don't need to iterate over the basic block again.
closes#667
