Allocating an extended tag is much cleaner and easier to reason about
than reusing an existing tag. The previous `.data = undefined` was a
clear indication that we don't have any data to store, and so might as
well store an extended tag in that space almost for free.
Fixes#15489
This also lays the groundwork for exposing the whether or not a function is
noinline in std.builtin.Fn as an `is_noinline: bool` field if we ever want to do that.
When the element is comptime-known, we can check if it has a repeated
byte representation. In this case, `@memset` can be lowered with the
LLVM intrinsic rather than with a loop.
In semaDecl, it was possible for a new ArenaAllocators state to replace an existing one that
hadn't been freed yet. Instead of the ref_count (which was made redundant by adding
the allocator parameter to `release`), I now store a pointer to the previous arena, if one exists.
This allows a recursive deinit to happen when the last arena created is destroyed.
This fixes a bug where resolveStructLayout to was promoting from stale
value_arena state which was then overwrriten when another ArenaAllocator
higher in the call stack saved its state back. This resulted in the memory
for struct_obj.optmized_order overlapping existing allocations.
My initial fix in c7067ef wasn't sufficient, as it only checked if the struct being
resolved had the same owner as the current sema instance. However, it's
possible for resolveStructLayout to be called when the sema instance
has a different owner, but the struct decl's value_arena is currently in
use higher up in the callstack.
This change introduces ValueArena, which holds the arena state as well as tracks
if an arena has already been promoted from it. This allows callers to use the
value_arena storage without needing to be aware of another user of this same storage
higher up in the call stack.
Often, a `dbg_stmt` ends up being associated with no real code because
whatever it referred to was eliminated by semantic analysis. In these
cases, Sema can replace the last `dbg_stmt` with the new one to avoid
redundant AIR instructions which at best are nops and at worst cause
backends to emit useless info (e.g. CBE does this).
store:
The value to store may be undefined, in which case the destination
memory region has undefined bytes after this instruction is
evaluated. In such case ignoring this instruction is legal
lowering.
store_safe:
Same as `store`, except if the value to store is undefined, the
memory region should be filled with 0xaa bytes, and any other
safety metadata such as Valgrind integrations should be notified of
this memory region being undefined.
* Sema: upgrade operands to array pointers if possible when emitting
AIR.
* Implement safety checks for length mismatch and aliasing.
* AIR: make ptrtoint support slice operands. Implement in LLVM backend.
* C backend: implement new `@memset` semantics. `@memcpy` is not done
yet.
Now they use slices or array pointers with any element type instead of
requiring byte pointers.
This is a breaking enhancement to the language.
The safety check for overlapping pointers will be implemented in a
future commit.
closes#14040
* docs(std.math): elaborate on difference between absCast and absInt
* docs(std.rand.Random.weightedIndex): elaborate on likelihood
I think this makes it easier to understand.
* langref: add small reminder
* docs(std.fs.path.extension): brevity
* docs(std.bit_set.StaticBitSet): mention the specific types
* std.debug.TTY: explain what purpose this struct serves
This should also make it clearer that this struct is not supposed to provide unrelated terminal manipulation functionality such as setting the cursor position or something because terminals are complicated and we should keep this struct simple and focused on debugging.
* langref(package listing): brevity
* langref: explain what exactly `threadlocal` causes to happen
* std.array_list: link between swapRemove and orderedRemove
Maybe this can serve as a TLDR and make it easier to decide.
* PrefetchOptions.locality: clarify docs that this is a range
This confused me previously and I thought I can only use either 0 or 3.
* fix typos and more
* std.builtin.CallingConvention: document some CCs
* langref: explain possibly cryptic names
I think it helps knowing what exactly these acronyms (@clz and @ctz) and
abbreviations (@popCount) mean.
* variadic function error: add missing preposition
* std.fmt.format docs: nicely hyphenate
* help menu: say what to optimize for
I think this is slightly more specific than just calling it
"optimizations". These are speed optimizations. I used the word
"performance" here.
Since the Zig language documentation claims support for `.Min` and
`.Max` in `@atomicRmw` with floats, allow in Sema and implement for both
the llvm and C backends.
Also remove an incorrect piece of logic which allowed fetching the 'len'
property on non-single-ptrs (e.g. many-ptrs) and add a corresponding
compile error test case.
Resolves: #4765
AmdgpuKernel and NvptxKernel are unified into a Kernel calling convention.
There is really no reason for these to be separate; no backend is allowed to
emit the calling convention of the other. This is in the same spirit as the
.Interrupt calling convention lowering to different LLVM calling conventions,
and opens the way for SPIR-V kernels to be exported using the Kernel calling
convention.
This lets us generate the store with knowledge of the type to be stored.
Therefore, we can avoid generating garbage Air with stores through
pointers to comptime-only types which backends cannot lower.
Closes#13410Closes#15122
* @workItemId returns the index of the work item in a work group for a
dimension.
* @workGroupId returns the index of the work group in the kernel dispatch for a
dimension.
* @workGroupSize returns the size of the work group for a dimension.
These builtins are mainly useful for GPU backends. They are currently only
implemented for the AMDGCN LLVM backend.
