Global constant initializers can reference functions, so forward declare
the constants and initialize them later with the function definitions,
which guarantees that they appear after all declarations.
Now instead of zig.h being baked into the compiler binary, it is a
header file distributed along with all the other header files
distributed with Zig.
Closes#11643
At least on Linux, the pwritev syscall checks the pointer and returns
EFAULT before it checks if the length is nonzero.
Perhaps this should be fixed in the standard library, however, these are
still improvements since they make the kernel do less work within the
syscall.
Rather than allocating Decl objects with an Allocator, we instead allocate
them with a SegmentedList. This provides four advantages:
* Stable memory so that one thread can access a Decl object while another
thread allocates additional Decl objects from this list.
* It allows us to use u32 indexes to reference Decl objects rather than
pointers, saving memory in Type, Value, and dependency sets.
* Using integers to reference Decl objects rather than pointers makes
serialization trivial.
* It provides a unique integer to be used for anonymous symbol names,
avoiding multi-threaded contention on an atomic counter.
* The `@bitCast` workaround is removed in favor of `@ptrCast` properly
doing element casting for slice element types. This required an
enhancement both to stage1 and stage2.
* stage1 incorrectly accepts `.{}` instead of `{}`. stage2 code that
abused this is fixed.
* Make some parameters comptime to support functions in switch
expressions (as opposed to making them function pointers).
* Avoid relying on local temporaries being mutable.
* Workarounds for when stage1 and stage2 disagree on function pointer
types.
* Workaround recursive formatting bug with a `@panic("TODO")`.
* Remove unreachable `else` prongs for some inferred error sets.
All in effort towards #89.
1. Changed Zig pointers to functions to be typedef'd so then we can
treat them the same as other types.
2. Distinguished between const slices (zig_L prefix) and mut slices
(zig_M prefix).
3. Changed lowering of Zig "const pointers" (e.g. *const u8) to to C
"pointers to const" (e.g. const char *) rather than C "const
pointers" (e.g. char * const)
4. Ensured that all typedefs are "linked" even if the decl doesn't
require any forward declarations
5. Added test that exercises function pointer type rendering
6. Changed .slice_ptr instruction to allocate pointer local rather than
a uintptr_t local
Because ArrayList.initCapacity uses 'precise' capacity allocation, this should save memory on average, and definitely will save memory in cases where ArrayList is used where a regular allocated slice could have also be used.
The ensureUnusedCapacity did not reserve a big enough number. I changed
it to no longer guess the capacity because I saw that the number of
possible items was not determinable ahead of time and this can therefore
avoid allocating more memory than necessary.
The C backend is the only backend that requires each decl to be output
in an order that satisfies the dependency graph. Here it is implemented
with a simple algorithm based on a `remaining_decls` set, using the
`dependencies` edges that are already stored for each Decl.
This satisfies incremental compilation as well as how `zig test` works,
which calls `updateDecl` on `test_functions`.
Previously, linker backends or machine code backends were able to hold
on to references to inside Sema's temporary arena. However there can
be large objects stored there that we want to free after machine code is
generated.
The primary change in this commit is to use a temporary arena for Sema
of function bodies that gets freed after machine code backend finishes
handling `updateFunc` (at the same time that Air and Liveness get freed).
The other changes in this commit are fixing issues that fell out from
the primary change.
* The C linker backend is rewritten to handle updateDecl and updateFunc
separately. Also, all Decl updates get access to typedefs and
fwd_decls, not only functions.
* The C linker backend is updated to the new API that does not depend
on allocateDeclIndexes and does not have to handle garbage collected
decls.
* The C linker backend uses an arena for Type/Value objects that
`typedefs` references. These can be garbage collected every so often
after flush(), however that garbage collection code is not
implemented at this time. It will be pretty simple, just allocate a
new arena, copy all the Type objects to it, update the keys of the
hash map, free the old arena.
* Sema: fix a handful of instances of not copying Type/Value objects
from the temporary arena into the appropriate Decl arena.
* Type: fix some function types not reporting hasCodeGenBits()
correctly.
to the link infrastructure, instead of being stored with Module.Fn. This
moves towards a strategy to make more efficient use of memory by not
storing Air or Liveness data in the Fn struct, but computing it on
demand, immediately sending it to the backend, and then immediately
freeing it.
Backends which want to defer codegen until flush() such as SPIR-V
must move the Air/Liveness data upon `updateFunc` being called and keep
track of that data in the backend implementation itself.
* ZIR: add two instructions:
- ret_err_value_code
- ret_err_value
* AstGen: add countDefers and utilize it to emit more efficient ZIR for
return expressions in the presence of defers.
* AstGen: implement |err| payloads for `errdefer` syntax.
- There is not an "unused capture" error for it yet.
* AstGen: `return error.Foo` syntax gets a hot path in return
expressions, using the new ZIR instructions. This also is part of
implementing inferred error sets, since we need to tell Sema to add
an error value to the inferred error set before it gets coerced.
* Sema: implement `@setCold`.
- Implement `@setCold` support for C backend.
* `@panic` and regular safety panics such as `unreachable` now properly
invoke `std.builtin.panic`.
* C backend: improve pointer and function value rendering.
* C linker: fix redundant typedefs.
* Add Type.error_set_inferred.
* Fix Value.format for enum_literal, enum_field_index, bytes.
* Remove the C backend test that checks for identical text
I measured a 14% reduction in Total ZIR Bytes from master branch
for std/os.zig.
- hash/eql functions moved into a Context object
- *Context functions pass an explicit context
- *Adapted functions pass specialized keys and contexts
- new getPtr() function returns a pointer to value
- remove functions renamed to fetchRemove
- new remove functions return bool
- removeAssertDiscard deleted, use assert(remove(...)) instead
- Keys and values are stored in separate arrays
- Entry is now {*K, *V}, the new KV is {K, V}
- BufSet/BufMap functions renamed to match other set/map types
- fixed iterating-while-modifying bug in src/link/C.zig
* Compilation: iteration over the deletion_set only tries to delete the
first one, relying on Decl destroy to remove itself from the deletion
set.
* link: `freeDecl` now has to handle the possibility of freeing a Decl
that was never called with `allocateDeclIndexes`.
* `deleteDecl` recursively iterates over a Decl's Namespace sub-Decl
objects and calls `deleteDecl` on them.
- Prevents Decl objects from being destroyed when they are still in
`deletion_set`.
* Sema: fix cleanup of anonymous Decl objects when an error occurs
during semantic analysis.
* tests: update test cases for fully qualified names
* Remove some unused imports in AstGen.zig. I think it would make sense
to start decoupling AstGen from the rest of the compiler code,
similar to how the tokenizer and parser are decoupled.
* AstGen: For decls, move the block_inline instructions to the top of
the function so that they get lower ZIR instruction indexes. With
this, the block_inline instruction index combined with its corresponding
break_inline instruction index can be used to form a ZIR instruction
range. This is useful for allocating an array to map ZIR instructions
to semantically analyzed instructions.
* Module: extract emit-h functionality into a struct, and only allocate
it when emit-h is activated.
* Module: remove the `decl_table` field. This previously was a table of
all Decls in the entire Module. A "name hash" strategy was used to
find decls within a given namespace, using this global table. Now,
each Namespace has its own map of name to children Decls.
- Additionally, there were 3 places that relied on iterating over
decl_table in order to function:
- C backend and SPIR-V backend. These now have their own decl_table
that they keep populated when `updateDecl` and `removeDecl` are
called.
- emit-h. A `decl_table` field has been added to the new GlobalEmitH
struct which is only allocated when emit-h is activated.
* Module: fix ZIR serialization/deserialization bug in debug mode having
to do with the secret safety tag for untagged unions. There is still an
open TODO to investigate a friendlier solution to this problem with
the language.
* Module: improve deserialization of ZIR to allocate only exactly as
much capacity as length in the instructions array so as to not waste
space.
* Module: move `srcHashEql` to `std.zig` to live next to the definition
of `SrcHash` itself.
* Module: re-introduce the logic for scanning top level declarations
within a namespace.
* Compilation: add an `analyze_pkg` Job which is used to kick off the
start of semantic analysis by doing the equivalent of
`_ = @import("std");`. The `analyze_pkg` job is unconditionally added
to the work queue on every update(), with pkg set to the std lib pkg.
* Rename TZIR to AIR in a few places. A more comprehensive rename will
come later.
This type is not widely applicable enough to be a public part of the
public interface of the std.
The current implementation in only fully utilized by the zig fmt
implementation, which could benefit by even tighter integration as
will be demonstrated in the next commit. Therefore, move the current
io.AutoIndentingStream to lib/std/zig/render.zig.
The C backend of the self hosted compiler also use this type currently,
but it does not require anywhere near its full complexity. Therefore,
implement a greatly simplified version of this interface in
src/codegen/c.zig.
