* Breaking language change: inline assembly must use string literal
syntax. This is in preparation for inline assembly improvements that
involve more integration with the Zig language. This means we cannot
rely on text substitution.
* Liveness: properly handle inline assembly and function calls with
more than 3 operands.
- More than 35 operands is not yet supported. This is a low priority
to implement.
- This required implementation in codegen.zig as well.
* Liveness: fix bug causing incorrect tomb bits.
* Sema: enable switch expressions that are evaluated at compile-time.
- Runtime switch instructions still need to be reworked in this
branch. There was a TODO left here (by me) with a suggestion to do
some bigger changes as part of the AIR memory reworking. Now that
time has come and I plan to honor the suggestion in a future commit
before merging this branch.
* AIR printing: fix missing ')' on alive instructions.
We're back to "hello world" working for the x86_64 backend.
Use `@` syntax to escape `_` when used as an identifier.
Remove the stage1 astgen prohibition against assigning from `_`
Note: there a few stage1 bugs preventing `_` from being used as an identifier
for a local variable or function parameter; these will be fixed by stage2.
They are unlikely to arise in real C code since identifiers starting with
underscore are reserved for the implementation.
Implement io_uring submission queue entry preparation methods for
epoll_ctl, poll_add and poll_remove.
Poll masks are designated as 32-bit little-endian integers as
specified in liburing's definitions.
Updated io_uring_prep_rw to take in an unsigned 64-bit address instead
of an anytype. io_uring_sqe by default assumes that the address
specified in a submission queue entry is an unsigned 64-bit integer.
* rename files to adhere to conventions
* remove unnecessary function / optionality
* fix merge conflict
* better panic message
* remove unnecessary TODO comment
* proper namespacing of declarations
* clean up documentation comments
* no copyright header needed for a brand new zig file that is not
copied from anywhere
Xoroshiro128+ is the current default non-cryptographic random
number generator.
This algorithm was designed to generate floating-point numbers, by
only using the top 53 bits. Lower bits have a significant bias, that
contradicts the documented properties for `rand.DefaultPrng`. This
also has implications on everything using `Random.fill()`, including
the way we generate random floating-point numbers.
In addition, Xoroshiro128+ has known issues. See for example:
- https://lemire.me/blog/2017/08/22/cracking-random-number-generators-xoroshiro128/
- https://www.pcg-random.org/posts/xoroshiro-fails-truncated.html
Xoshiro256++ addresses these issues, while remaining very fast.
It now displays the byte with proper printability handling. This makes
the relevant compile error test case no longer a regression in quality
from stage1 to stage2.
In order to not regress the quality of compile errors, some improvements
had to be made.
* std.zig.parseCharLiteral is improved to return more detailed parse
failure information.
* tokenizer is improved to handle null bytes in the middle of strings,
character literals, and line comments.
* validating how many unicode escape digits in string literals is moved
to std.zig.parseStringLiteral rather than handled in the tokenizer.
* when a tokenizer error occurs, if the reported token is the 'invalid'
tag, an error note is added to point to the invalid byte location.
Further improvements would be:
- Mention the expected set of allowed bytes at this location.
- Display the invalid byte (if printable, print it, otherwise
escape-print it).
By requiring the source file to be null-terminated, we avoid extra
branching while simplifying the logic at the same time.
Running ast-check on a large zig source file (udivmodti4_test.zig),
master branch compared to this commit:
* 4% faster wall clock
* 7% fewer cache misses
* 1% fewer branches
The motivation for this commit is that there exists source files which
produce ast-check errors, but crash stage1 or otherwise trigger stage1
bugs. Previously to this commit, Zig would run AstGen, collect the
compile errors, run stage1, report stage1 compile errors and exit if
any, and then report AstGen compile errors.
The main change in this commit is to report AstGen errors prior to
invoking stage1, and in fact if any AstGen errors occur, do not invoke
stage1 at all.
This caused most of the compile error tests to fail due to things such
as unused local variables and mismatched stage1/stage2 error messages.
It was taking a long time to update the test cases one-by-one, so I
took this opportunity to unify the stage1 and stage2 testing harness,
specifically with regards to compile errors. In this way we can start
keeping track of which tests pass for 1, 2, or both.
`zig build test-compile-errors` no longer works; it is now integrated
into `zig build test-stage2`.
This is one step closer to executing compile error tests in parallel; in
fact the ThreadPool object is already in scope.
There are some cases where the stage1 compile errors were actually
better; those are left failing in this commit, to be addressed in a
follow-up commit.
Other changes in this commit:
* build.zig: improve support for -Dstage1 used with the test step.
* AstGen: minor cosmetic changes to error messages.
* stage2: add -fstage1 and -fno-stage1 flags. This now allows one to
download a binary of the zig compiler and use the llvm backend of
self-hosted. This was also needed for hooking up the test harness.
However, I realized that stage1 calls exit() and also has memory
leaks, so had to complicate the test harness by not using this flag
after all and instead invoking as a child process.
- These CLI flags will disappear once we start shipping the
self-hosted compiler as the main compiler. Until then, they can be
used to try out the work-in-progress stage2.
* stage2: select the LLVM backend by default for release modes, as long
as the target architecture is supported by LLVM.
* test harness: support setting the optimize mode
* AstGen: implement "unreachable code" error for blocks. This works at
the statement level.
* stage1: remove the "unreachable code" error implementation, which
means removing the `is_gen` field from IrInstSrc. This is one small
step towards a smaller memory footprint for stage1. The benefits
won't be realized until a future commit because this flag took
advantage of padding.
There may be a regression here with "union has no associated enum"
error, and there is a regression with the following code:
```zig
const a = noreturn;
```
A future commit will address these regressions.
When a floating-point value with no fractional part is shoved into an
integer type we must check whether it fits or not before calling
`@floatToInt` as the builtin panics in case of overflow.
Catch the error and bubble it up to the caller.
