Prior to this commit, the AIR arg instruction kept a reference to a ZIR
string index for the corresponding parameter name. This is used by DWARF
emitting code. However, this is a design flaw because we want AIR
objects to be independent from ZIR.
This commit saves the parameter names into memory managed by
`Module.Fn`. This is sub-optimal because we should be able to get the
parameter names from the ZIR for a function without having them
redundantly stored along with `Fn` memory. However the current way that
ZIR param instructions are encoded does not support this case. They
appear in the same ZIR body as the function instruction, just before it.
Instead, they should be embedded within the function instruction, which
will allow this TODO to be solved. That improvement is too big for this
commit, however.
After this there is one last dependency to untangle, which is for inline
assembly. The issue for that is #10784.
For some errors if the found token is not on the same line as
the previous token, point to the end of the previous token.
This usually results in more helpful errors.
When Sema sees a store_node instruction, it now checks for
the possibility of this pattern:
%a = ret_ptr
%b = store(%a, %c)
Where %c is an error union. In such case we need to add to the
current function's inferred error set, if any.
Coercion from error union to error union will be handled ideally if the
operand is comptime known. In such case it does the appropriate
unwrapping, then wraps again.
In the future, coercion from error union to error union should do the
same thing for a runtime value; emitting a runtime branch to check if
the value is an error or not.
`Value.arrayLen` for structs returns the number of fields. This is so
that Liveness can use it for the `vector_init` instruction (soon to be
renamed to `aggregate_init`).
For example, a situation like this is allowed
```zig
extern "c" var stderrp: c_int;
```
In this case, `Module.Var` wrapping `stderrp` will have `lib_name`
populated with the library name where this import is expected.
`ExternFn` will contain a maybe-lib-name if it was defined with
the `extern` keyword like so
```zig
extern "c" fn write(usize, usize, usize) usize;
```
`lib_name` will live as long as `ExternFn` decl does.
Clarify that `astgen.advanceSourceCursor` already increments absolute
values of the line and columns numbers; i.e., `GenZir.calcLine` is thus
not only obsolete but wrong by design.
Incidentally, this clean up allows for specifying the `FnDecl` line
numbers for DWARF use correctly as relative values with respect to
the start of the parent `Decl`. This `Decl` in turn has its line number
information specified relatively to its parent `Decl`, and so on, until
we reach the global scope.
AstGen:
* rename the known_has_bits flag to known_non_opv to make it better
reflect what it actually means.
* add a known_comptime_only flag.
* make the flags take advantage of identifiers of primitives and the
fact that zig has no shadowing.
* correct the known_non_opv flag for function bodies.
Sema:
* Rename `hasCodeGenBits` to `hasRuntimeBits` to better reflect what it
does.
- This function got a bit more complicated in this commit because of
the duality of function bodies: on one hand they have runtime bits,
but on the other hand they require being comptime known.
* WipAnonDecl now takes a LazySrcDecl parameter and performs the type
resolutions that it needs during finish().
* Implement comptime `@ptrToInt`.
Codegen:
* Improved handling of lowering decl_ref; make it work for
comptime-known ptr-to-int values.
- This same change had to be made many different times; perhaps we
should look into merging the implementations of `genTypedValue`
across x86, arm, aarch64, and riscv.
This commit updates stage2 to enforce the property that the syntax
`fn()void` is a function *body* not a *pointer*. To get a pointer, the
syntax `*const fn()void` is required.
ZIR puts function alignment into the func instruction rather than the
decl because this way it makes it into function types. LLVM backend
respects function alignments.
Struct and Union have methods `fieldSrcLoc` to help look up source
locations of their fields. These trigger full loading, tokenization, and
parsing of source files, so should only be called once it is confirmed
that an error message needs to be printed.
There are some nice new error hints for explaining why a type is
required to be comptime, particularly for structs that contain function
body types.
`Type.requiresComptime` is now moved into Sema because it can fail and
might need to trigger field type resolution. Comptime pointer loading
takes into account types that do not have a well-defined memory layout
and does not try to compute a byte offset for them.
`fn()void` syntax no longer secretly makes a pointer. You get a function
body type, which requires comptime. However a pointer to a function body
can be runtime known (obviously).
Compile errors that report "expected pointer, found ..." are factored
out into convenience functions `checkPtrOperand` and `checkPtrType` and
have a note about function pointers.
Implemented `Value.hash` for functions, enum literals, and undefined values.
stage1 is not updated to this (yet?), so some workarounds and disabled
tests are needed to keep everything working. Should we update stage1 to
these new type semantics? Yes probably because I don't want to add too
much conditional compilation logic in the std lib for the different
backends.
When asking a struct or union whether the type requires comptime, it may
need to ask itself recursively, for example because of a field which is
a pointer to itself. This commit adds a field to each to keep track of
when computing the "requires comptime" value and returns `false` if the
check is already ongoing.
Previously, breaking from an outer block at comptime would result in
incorrect control flow. Now there is a mechanism, `error.ComptimeBreak`,
similar to `error.ComptimeReturn`, to send comptime control flow further
up the stack, to its matching block.
This commit also introduces a new log scope. To use it, pass
`--debug-log sema_zir` and you will see 1 line per ZIR instruction
semantically analyzed. This is useful when you want to understand what
comptime control flow is doing while debugging the compiler.
One more `switch` test case is passing.
It is the job of codegen backends to mark Decls that are referenced as
alive so that the frontend does not sweep them with the garbage. This
commit unifies the code between the backends with an added method on
Decl.
The implementation is more complete than before, switching on the Decl
val tag and recursing into sub-values.
As a result, two more array tests are passing.
`runtime_param_index` is used to get the parameter type from `fn_type`,
but this variable was not incremented for zero sized parameters, causing
two zero sized parameters of different type to cause miss complication.
resolveTypeForCodegen is called when we needed to resolve a type fully,
even through pointer. This commit fully implements this, even through
pointer fields on structs and unions.
The function has now also been renamed to resolveTypeFully
Previously the code asserted source files were already loaded, but this
is not the case when cached ZIR is loaded. Now it will trigger .zig
source code to be loaded for the purposes of hashing the source for
`CacheMode.whole`.
This additionally refactors stat_size, stat_inode, and stat_mtime fields
into using the `Cache.File.Stat` struct.
when using `CacheMode.whole`. Also, I verified that `addDepFilePost` is
in fact including the original C source file in addition to the files it
depends on.
The two CacheMode values are `whole` and `incremental`.
`incremental` is what we had before; `whole` is new.
Whole cache mode uses everything as inputs to the cache hash;
and when a hit occurs it skips everything including linking.
This is ideal for when source files change rarely and for backends that
do not have good incremental compilation support, for example
compiler-rt or libc compiled with LLVM with optimizations on.
This is the main motivation for the additional mode, so that we can have
LLVM-optimized compiler-rt/libc builds, without waiting for the LLVM
backend every single time Zig is invoked.
Incremental cache mode hashes only the input file path and a few target
options, intentionally relying on collisions to locate already-existing
build artifacts which can then be incrementally updated.
The bespoke logic for caching stage1 backend build artifacts
is removed since we now have a global caching mechanism for
when we want to cache the entire compilation, *including* linking.
Previously we had to get "creative" with libs.txt and a special
byte in the hash id to communicate flags, so that when the cached
artifacts were re-linked, we had this information from stage1
even though we didn't actually run it. Now that `CacheMode.whole`
includes linking, this extra information does not need to be
preserved for cache hits. So although this changeset introduces
complexity, it also removes complexity.
The main trickiness here comes from the inherent differences between the
two modes: `incremental` wants a directory immediately to operate on,
while `whole` doesn't know the output directory until the compilation is
complete. This commit deals with this problem mostly inside `update()`,
where, on a cache miss, it replaces `zig_cache_artifact_directory` with a
temporary directory, and then renames it into place once the compilation is
complete.
Items remaining before this branch can be merged:
* [ ] make sure these things make it into the cache manifest:
- @import files
- @embedFile files
- we already add dep files from c but make sure the main .c files make
it in there too, not just the included files
* [ ] double check that the emit paths of other things besides the binary
are working correctly.
* [ ] test `-fno-emit-bin` + `-fstage1`
* [ ] test `-femit-bin=foo` + `-fstage1`
* [ ] implib emit directory copies bin_file_emit directory in create() and needs
to be adjusted to be overridden as well.
* [ ] make sure emit-h is handled correctly in the cache hash
* [ ] Cache: detect duplicate files added to the manifest
Some preliminary performance measurements of wall clock time and
peak RSS used:
stage1 behavior (1077 tests), llvm backend, release build:
* cold global cache: 4.6s, 1.1 GiB
* warm global cache: 3.4s, 980 MiB
stage2 master branch behavior (575 tests), llvm backend, release build:
* cold global cache: 0.62s, 191 MiB
* warm global cache: 0.40s, 128 MiB
stage2 this branch behavior (575 tests), llvm backend, release build:
* cold global cache: 0.62s, 179 MiB
* warm global cache: 0.27s, 90 MiB
* `Module.Union.getLayout`: fixes to support components of the union
being 0 bits.
* Implement `@typeInfo` for unions.
* Add missing calls to `resolveTypeFields`.
* Fix explicitly-provided union tag types passing a `Zir.Inst.Ref`
where an `Air.Inst.Ref` was expected. We don't have any type safety
for this; these typess are aliases.
* Fix explicitly-provided `union(enum)` tag Values allocated to the
wrong arena.
Layout algorithm: all `align(0)` fields are squished together as if they
were a single integer with a number of bits equal to `@bitSizeOf` each
field added together. Then the natural ABI alignment of that integer is
used for that pseudo-field.
This allows the inferred error set of comptime and inline invocations to be
resolved separately from the inferred error set of the runtime version or other
comptime/inline invocations.
All Zig code is eligible to `@import("builtin")` which is mapped to a
generated file, build.zig, based on the target and other settings.
Zig invocations which share the same target settings will generate the
same builtin.zig file and thus the path to builtin.zig is in a shared
cache folder, and different projects can sometimes use the same file.
Before this commit, this led to race conditions where multiple
invocations of `zig` would race to write this file. If one process
wanted to *read* the file while the other process *wrote* the file, the
reading process could observe a truncated or partially written
builtin.zig file.
This commit makes the following improvements:
- limitations:
- avoid clobbering the inode, mtime in the hot path
- avoid creating a partially written file
- builtin.zig needs to be on disk for debug info / stack trace purposes
- don't mark the task as complete until the file is finished being populated
(possibly by an external process)
- strategy:
- create the `@import("builtin")` `Module.File` during the AstGen
work, based on generating the contents in memory rather than
loading from disk.
- write builtin.zig in a separate task that doesn't have
to complete until the end of the AstGen work queue so that it
can be done in parallel with everything else.
- when writing the file, first stat the file path. If it exists, we are done.
- otherwise, write the file to a temp file in the same directory and atomically
rename it into place (clobbering the inode, mtime in the cold path).
- summary:
- all limitations respected
- hot path: one stat() syscall that happens in a worker thread
This required adding a missing function to the standard library:
`std.fs.Dir.statFile`. In this commit, it does open() and then fstat()
which is two syscalls. It should be improved in a future commit to only
make one.
Fixes#9439.
- Correctly load slice value on stack
- Implement WrapErrorUnionErr and payload
- Implement trunc, fix sliceLen and write undefined
- Implement slice as return type and argument
Note: This also fixes a memory leak for inferred error sets, and for usingnamespace
This reverts commit 725267f7c20f0ba588b472048a8c1fe1a328c714, reversing
changes made to 2dae860de3494f97c9477af9282fe0131ff5c4cb.
This test is failing:
```zig
pub fn main() u8 {
var e = foo();
const i = e catch 69;
return i;
}
fn foo() anyerror!u8 {
return 5;
}
```
It's returning 69 instead of the expected value 5.
When adding test coverage, I noticed an inconsistency in which source
location the compile error was pointing to for `@embedFile` errors vs
`@import` errors. They now both point to the same place, the string
operand.
closes#9404closes#9939
* Introduce a mechanism into Sema for emitting a compile error when an
integer is too big and we need it to fit into a usize.
* Add `@intCast` where necessary
* link/MachO: fix an unnecessary allocation when all that was happening
was appending zeroes to an ArrayList.
* Add `error.Overflow` as a possible error to some codepaths, allowing
usage of `math.intCast`.
closes#9710
