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.
New search system is based on a Radix Tree. The Radix Tree contains a shallow list of all decl names (ie no paths), plus some suffixes, split by following the official style guide (eg "HashMapUnmanaged" also produces "MapUnmanaged" and "Unmanaged", same with snake_case and camelCase names).
Additionally, the search system uses the decl graph data to recognize hierarchical relationships between decls, allowing you to zero on a target namespace for search. As an example "fs create" will score highe all things related to the creation of files and directories inside of `std.fs`, while still showing (but with lower score) matches from `std.Bulild`.
As another example "fs windows" will prioritize windows-related results in `std.fs`, while "windows fs" will prioritize fs-related results in `std.windows`.
If the C code had variables that were named the same as the prefixes used
for name mangling, such as "tmp" or "ref", then the codegen would generate
incorrect code in some cases. This was because these aliases were immediately
visible to expressions that actually needed to use the original name.
I introduced the concept of reserving aliases without enabling them. An alias
that isn't enabled isn't visible to expression translation, but is still
reserved so that sub-expressions generate aliases that don't overlap.
Add test cases to cover the cases that would break before this change.
Co-authored-by: Veikka Tuominen <git@vexu.eu>
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).
Pointer comparisons were triggering `-Wcompare-distinct-pointer-types`
before this fix, which adds `(void*)` casts if the lhs type and rhs type
do not match pointer sizeness.
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.
Previously, this code casted the array pointer to u8 pointer, but I
removed that in a different commit. This commit restores the cast, but
instead of hard-coding u8, it uses the destination element pointer,
since memset now supports arbitrary element types.
* 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.
Rather than using a function call to verify if an error fits within
the global error set's length, we now store the error set' size in
the .rodata segment of the linear memory and load that value onto
the stack to check with the integer value.
This implements the safety check for error casts. The instruction
generates a jump table with 2 possibilities. The operand is used
as an index into the jump table. For cases where the value does
not exist within the error set, it will generate a jump to the
'false' block. For cases where it does exist, it will generate
a jump to the 'true' block. By calculating the highest and lowest
value we can keep the jump table smaller, as it doesn't need to
contain an index into the entire error set.
Creates a global undefined symbol when this instruction is called.
The linker will then resolve it as a lazy symbol, ensuring it is
only generated when the symbol was created. In `flush` it will then
generate the function as only then, all errors are known and we can
generate the function body. This logic allows us to re-use the same
functionality of linker-synthetic-functions.
