There were two things to resolve here:
* Snektron's branch edited Zir printing, but in master branch
I moved the printing code from Zir.zig to print_zir.zig. So that
just had to be moved over.
* In master branch I fleshed out coerceInMemory a bit more, which
caused one of Snektron's test cases to fail, so I had to add
addrspace awareness to that. Once I did that the tests passed again.
In a previous commit (f4d3d29), syntax checking for code blocks with the
`syntax` type was disabled due to a change in astgen now checking the existence of
identifiers. The change in astgen caused some code samples in the language
reference to cause compilation errors.
This commit updates the code samples in the language reference and
re-enables syntax checking. Some code samples have been changed to unchecked
syntax blocks using `{#syntax_block#}` when suitable.
* introduce float_to_int and int_to_float AIR instructionts and
implement for the LLVM backend and C backend.
* Sema: implement `zirIntToFloat`.
* Sema: implement `@atomicRmw` comptime evaluation
- introduce `storePtrVal` for when one needs to store a Value to a
pointer which is a Value, and assert it happens at comptime.
* Value: introduce new functionality:
- intToFloat
- numberAddWrap
- numberSubWrap
- numberMax
- numberMin
- bitwiseAnd
- bitwiseNand (not implemented yet)
- bitwiseOr
- bitwiseXor
* Sema: hook up `zirBitwise` to the new Value bitwise implementations
* Type: rename `isFloat` to `isRuntimeFloat` because it returns `false`
for `comptime_float`.
This edit allows the reader to understand the syntax this section is talking about more quickly – they don’t have to read the whole code block and understand which part of it demonstrates the feature being described.
Affects https://ziglang.org/documentation/master/#Inferred-Error-Sets
The WebAssembly spec requires signed LEB128 to be encoded up to a maximum number of bytes (max 5 bytes for i32, max 10 bytes for i64) and that "unused" bits are all 0 if the number is positive and all 1 if the number is negative. The Zig LEB128 implementation already enforces the max number of bytes and does check the unused bytes https://github.com/ziglang/zig/blob/master/lib/std/leb128.zig#L70-L79.
However, the WebAssembly test suite has a number of tests that were failing validation (expecting the wasm module to fail validation, but when running the tests, those examples were actually passing validation):
https://github.com/malcolmstill/foxwren/blob/master/test/testsuite/binary-leb128.wast#L893-L902https://github.com/malcolmstill/foxwren/blob/master/test/testsuite/binary-leb128.wast#L934-L943
Notably the failures are both cases of negative numbers and the top 4 bits of the last byte are zero. And I believe this is the issue: we're only currently checking the "unused" / remaining_bits if we overflow, but in the case of 0x0_ no overflow happens and so the bits go unchecked.
In other words:
\xff\xff\xff\xff\7f rightly successfully decodes (because it overflows and the remaining bits are 0b1111)
\xff\xff\xff\xff\6f rightly errors with overflow (because it overflows and the remaining bits are 0b1110)
\xff\xff\xff\xff\0f incorrectly decodes when it should error (because the top 4 bits are all 0, and so no overflow occurs and no check that the unused bits are 1 happens)
This PR adds a the remaining_bits check in an else branch of the @shlWithOverflow when we're looking at the last byte and the number being decoded is negative.
Note: this means a couple of the test cases in leb128.zig that are down as decoding shouldn't actually decode so I added the appropriate 1 bits.
This is a property which solely belongs to pointers to functions,
not to the functions themselves. This cannot be properly represented by
stage 2 at the moment, as type with zigTypeTag() == .Fn is overloaded for
for function pointers and function prototypes.
Validity checks are also based on context; whether the entity being validated
is a mutable/constant value, a pointer (that is ascripted with an addrspace
attribute) or a function with an addrspace attribute. Error messages are
relatively simple for now.
Adds AST generation for address spaces on pointers, function prototypes,
function declarations and variable declarations. In the latter two cases,
declaration properties were already stored more efficiently in a declaration
structure. To accomodate these for address spaces, the bit indicating presence
of a linksection attribute has been extended to include either linksection,
address space, or both.
I believe these are Linux specific so they will need to be os-gated
in `elf.zig` at some point, but I reckon it should be fine to have
them as-is right now since the ELF linker work will mainly be done
on x86-64 Linux at first.
