* Implement Sema for `@cmpxchgWeak` and `@cmpxchgStrong`. Both runtime
and comptime codepaths are implement.
* Implement Codegen for LLVM backend and C backend.
* Add LazySrcLoc.node_offset_builtin_call_argX 3...5
* Sema: rework comptime control flow.
- `error.ComptimeReturn` is used to signal that a comptime function
call has returned a result (stored in the Inlining struct).
`analyzeCall` notices this and handles the result.
- The ZIR instructions `break_inline`, `block_inline`,
`condbr_inline` are now redundant and can be deleted. `break`,
`block`, and `condbr` function equivalently inside a comptime scope.
- The ZIR instructions `loop` and `repeat` also are modified to
directly perform comptime control flow inside a comptime scope,
skipping an unnecessary mechanism for analysis of runtime code.
This makes Zig perform closer to an interpreter when evaluating
comptime code.
* Sema: zirRetErrValue looks at Sema.ret_fn_ty rather than sema.func
for adding to the inferred error set. This fixes a bug for
inlined/comptime function calls.
* Implement ZIR printing for cmpxchg.
* stage1: make cmpxchg respect --single-threaded
- Our LLVM C++ API wrapper failed to expose this boolean flag before.
* Fix AIR printing for struct fields showing incorrect liveness data.
- adds 1 simple behavior tests for each
which does integer and vector ops at
runtime and comptime
- adds bigint_*_sat() methods for each
- use CreateIntrinsic() which accepts a
variable number of arguments to pass
the scale parameter
* update langref
- added case to test/compile_errors.zig given floats
- explain upstream bug in llvm.smul.fix.sat and link to #9643 in langref and commented out test cases
* sat-arithmetic: skip mul tests if arch == .wasm32 because ci is erroring with 'LLVM ERROR: Unable to expand fixed point multiplication' when compiling for wasm32
The big change in this commit is making `semaDecl` resolve the fields if
the Decl ends up being a struct or union. It needs to do this while
the `Sema` is still in scope, because it will have the resolved AIR
instructions that the field type expressions possibly reference. We do
this after the decl is populated and set to `complete` so that a `Decl`
may reference itself.
Everything else is fixes and improvements to make the test suite pass
again after making this change.
* New AIR instruction: `ptr_elem_ptr`
- Implemented for LLVM backend
* New Type tag: `type_info` which represents `std.builtin.TypeInfo`. It
is used by AstGen for the operand type of `@Type`.
* ZIR instruction `set_float_mode` uses `coerced_ty` to avoid
superfluous `as` instruction on operand.
* ZIR instruction `Type` uses `coerced_ty` to properly handle result
location type of operand.
* Fix two instances of `enum_nonexhaustive` Value Tag not handled
properly - it should generally be handled the same as `enum_full`.
* Fix struct and union field resolution not copying Type and Value
objects into its Decl arena.
* Fix enum tag value resolution discarding the ZIR=>AIR instruction map
for the child Sema, when they still needed to be accessed.
* Fix `zirResolveInferredAlloc` use-after-free in the AIR instructions
data array.
* Fix `elemPtrArray` not respecting const/mutable attribute of pointer
in the result type.
* Fix LLVM backend crashing when `updateDeclExports` is called before
`updateDecl`/`updateFunc` (which is, according to the API, perfectly
legal for the frontend to do).
* Fix LLVM backend handling element pointer of pointer-to-array. It
needed another index in the GEP otherwise LLVM saw the wrong type.
* Fix LLVM test cases not returning 0 from main, causing test failures.
Fixes a regression introduced in
6a5094872f10acc629543cc7f10533b438d0283a.
* Implement comptime shift-right.
* Implement `@Type` for integers and `@TypeInfo` for integers.
* Implement union initialization syntax.
* Implement `zirFieldType` for unions.
* Implement `elemPtrArray` for a runtime-known operand.
* Make `zirLog2IntType` support RHS of shift being `comptime_int`. In
this case it returns `comptime_int`.
The motivating test case for this commit was originally:
```zig
test "example" {
var l: List(10) = undefined;
l.array[1] = 1;
}
fn List(comptime L: usize) type {
var T = u8;
return struct {
array: [L]T,
};
}
```
However I changed it to:
```zig
test "example" {
var l: List = undefined;
l.array[1] = 1;
}
const List = blk: {
const T = [10]u8;
break :blk struct {
array: T,
};
};
```
Which ended up being a similar, smaller problem. The former test case
will require a similar solution in the implementation of comptime
function calls - checking if the result of the function call is a struct
or union, and using the child `Sema` before it is destroyed to resolve
the fields.
* Introduce `ret_load` ZIR instruction which does return semantics
based on a corresponding `ret_ptr` instruction. If the return type of
the function has storage for the return type, it simply returns.
However if the return type of the function is by-value, it loads the
return value from the `ret_ptr` allocation and returns that.
* AstGen: improve `finishThenElseBlock` to not emit break instructions
after a return instruction in the same block.
* Sema: `ret_ptr` instruction works correctly in comptime contexts.
Same with `alloc_mut`.
The test case with a recursive inline function having an implicitly
comptime return value now has a runtime return value because of the fact
that it calls a function in a non-comptime context.
When doing a function call, if the return type requires comptime, the
function is analyzed as an inline/comptime call.
There is an important TODO here. I will reproduce the comment from this
commit:
> In the case of a comptime/inline function call of a generic function,
> the function return type needs to be the resolved return type based on
> the function parameter type expressions being evaluated with comptime arguments
> passed in. Otherwise, it ends up being .generic_poison and failing the
> comptime/inline function call analysis.
* ZIR encoding for function instructions have a body for the return
type. This lets Sema for generic functions do the same thing it does
for parameters, handling `error.GenericPoison` in the evaluation of
the return type by marking the function as generic.
* Sema: fix missing block around the new Decl arena finalization. This
led to a memory corruption.
* Added some floating point support to the LLVM backend but didn't get
far enough to pass any new tests.
Module has a new field `monomorphed_funcs` which stores the set of
`*Module.Fn` objects which are generic function instantiations.
The hash is based on hashes of comptime values of parameters known to be
comptime based on an explicit comptime keyword or must-be-comptime
type expressions that can be evaluated without performing monomorphization.
This allows function calls to be semantically analyzed cheaply for
generic functions which are already instantiated.
The table is updated with a single `getOrPutAdapted` in the semantic
analysis of `call` instructions, by pre-allocating the `Fn` object and
passing it to the child `Sema`.
AstGen result locations now have a `coerced_ty` tag which is the same as
`ty` except it assumes that Sema will do a coercion, so it does not
redundantly add an `as` instruction into the ZIR code. This results in
cleaner ZIR and about a 14% reduction of ZIR bytes.
param and param_comptime ZIR instructions now have a block body for
their type expressions. This allows Sema to skip evaluation of the
block in the case that the parameter is comptime-provided. It also
allows a new mechanism to function: when evaluating type expressions of
generic functions, if it would depend on another parameter, it returns
`error.GenericPoison` which bubbles up and then is caught by the
param/param_comptime instruction and then handled.
This allows parameters to be evaluated independently so that the type
info for functions which have comptime or anytype parameters will still
have types populated for parameters that do not depend on values of
previous parameters (because evaluation of their param blocks will return
successfully instead of `error.GenericPoison`).
It also makes iteration over the block that contains function parameters
slightly more efficient since it now only contains the param
instructions.
Finally, it fixes the case where a generic function type expression contains
a function prototype. Formerly, this situation would cause shared state
to clobber each other; now it is in a proper tree structure so that
can't happen. This fix also required adding a field to Sema
`comptime_args_fn_inst` to make sure that the `comptime_args` field
passed into Sema is applied to the correct `func` instruction.
Source location for `node_offset_asm_ret_ty` is fixed; it was pointing at
the asm output name rather than the return type as intended.
Generic function instantiation is fixed, notably with respect to
parameter type expressions that depend on previous parameters, and with
respect to types which must be always comptime-known. This involves
passing all the comptime arguments at a callsite of a generic function,
and allowing the generic function semantic analysis to coerce the values
to the proper types (since it has access to the evaluated parameter type
expressions) and then decide based on the type whether the parameter is
runtime known or not. In the case of explicitly marked `comptime`
parameters, there is a check at the semantic analysis of the `call`
instruction.
Semantic analysis of `call` instructions does type coercion on the
arguments, which is needed both for generic functions and to make up for
using `coerced_ty` result locations (mentioned above).
Tasks left in this branch:
* Implement the memoization table.
* Add test coverage.
* Improve error reporting and source locations for compile errors.
The general strategy is that Sema will pre-map comptime arguments into
the inst_map, and then re-run the block body that contains the `param`
and `func` instructions. This re-runs all the parameter type expressions
except with comptime values populated.
In Sema, param instructions are now handled specially: they detect
whether they are comptime-elided or not. If so, they skip putting a
value in the inst_map, since it is already pre-populated. If not, then
they append to the `fields` field of `Sema` for use with the `func`
instruction.
So when the block body is re-run, a new function is generated with
all the comptime arguments elided, and the new function type has only
runtime parameters in it. TODO: give the generated Decls better names
than "foo__anon_x".
The new function is then added to the work queue to have its body
analyzed and a runtime call AIR instruction to the new function is
emitted.
When the new function gets semantically analyzed, comptime parameters are
pre-mapped to the corresponding `comptime_args` values rather than
mapped to an `arg` AIR instruction. `comptime_args` is a new field that
`Fn` has which is a `TypedValue` for each parameter. This field is non-null
for generic function instantiations only. The values are the comptime
arguments. For non-comptime parameters, a sentinel value is used. This is
because we need to know the information of which parameters are
comptime-known.
Additionally:
* AstGen: align and section expressions are evaluated in the scope that
has comptime parameters in it.
There are still some TODO items left; see the BRANCH_TODO file.
* ZIR function instructions encode the index of the block that
contains the function instruction. This allows Zig to later scan the
block and find the parameter instructions, which is needed for
semantically analyzing function bodies.
* Runtime function calls insert AIR arg instructions and then inserts
Sema inst_map entries mapping the ZIR param instructions to them.
* comptime/inline function call inserts Sema inst_map entries mapping
the ZIR param instructions to the AIR callsite arguments.
With this commit we are back to the tests passing.
ZIR encoding for functions is changed in preparation for generic
function support. As an example:
```zig
const std = @import("std");
const expect = std.testing.expect;
test "example" {
var x: usize = 0;
x += checkSize(i32, 1);
x += checkSize(bool, true);
try expect(x == 5);
}
fn checkSize(comptime T: type, x: T) usize {
_ = x;
return @sizeOf(T);
}
```
Previous ZIR for the `checkSize` function:
```zir
[165] checkSize line(10) hash(0226f62e189fd0b1c5fca02cf4617562): %55 = block_inline({
%56 = decl_val("T") token_offset:11:35
%57 = as_node(@Ref.type_type, %56) node_offset:11:35
%69 = extended(func([comptime @Ref.type_type, %57], @Ref.usize_type, {
%58 = arg("T") token_offset:11:23
%59 = as_node(@Ref.type_type, %58) node_offset:11:35
%60 = arg("x") token_offset:11:32
%61 = dbg_stmt(11, 4)
```
ZIR for the `checkSize` function after this commit:
```zir
[157] checkSize line(10) hash(0226f62e189fd0b1c5fca02cf4617562): %55 = block_inline({
%56 = param_comptime("T", @Ref.type_type) token_offset:11:23
%57 = as_node(@Ref.type_type, %56) node_offset:11:35
%58 = param("x", %57) token_offset:11:32
%67 = func(@Ref.usize_type, {
%59 = dbg_stmt(11, 4)
```
Noted differences:
* Previously the type expression was redundantly repeated.
* Previously the parameter names were redundantly stored in the ZIR
extra array.
* Instead of `arg` ZIR instructions as the first instructions within a
function body, they are now outside the function body, in the same
block as the `func` instruction. There are variants:
- param
- param_comptime
- param_anytype
- param_anytype_comptime
* The param instructions additionally encode the type.
* Because of the param instructions, the `func` instruction no longer
encodes the list of parameter types or the comptime bits.
It's implied that Sema will collect the parameters so that when a `func`
instruction is encountered, they will be implicitly used to construct
the function's type. This is so that we can satisfy all 3 ways of
performing semantic analysis on a function:
1. runtime: Sema will insert AIR arg instructions for each parameter,
and insert into the Sema inst_map ZIR param => AIR arg.
2. comptime/inline: Sema will insert into the inst_map ZIR param =>
callsite arguments.
3. generic: Sema will map *only the comptime* ZIR param instructions to
the AIR instructions for the comptime arguments at the callsite, and
then re-run Sema for the function's Decl. This will produce a new
function which is the monomorphized function.
Additionally:
* AstGen: Update usage of deprecated `ensureCapacity` to
`ensureUnusedCapacity` or `ensureTotalCapacity`.
* Introduce `Type.fnInfo` for getting a bunch of data about a function
type at once, and use it in `analyzeCall`.
This commit starts a branch to implement generic functions in stage2.
Test regressions have not been addressed yet.
`func_extended` ZIR instructions now have a one of the unused flags used
as a `has_comptime_bits` boolean. When set, it means 1 or more
parameters are `comptime`. In this case, there is a u32 per every 32
parameters (usually just 1 u32) with each bit indicating whether the
corresponding parameter is `comptime`.
Sema uses this information to correctly mark generic functions as
generic. There is now a TODO compile error in place in case a generic
function call happens. A future commit will do the generic function call
implementation.
@select(
comptime T: type,
pred: std.meta.Vector(len, bool),
a: std.meta.Vector(len, T),
b: std.meta.Vector(len, T)
) std.meta.Vector(len, T)
Constructs a vector from a & b, based on the values in the predicate vector. For indices where the predicate value is true, the corresponding
element from the a vector is selected, and otherwise from b.
* There is now a main_pkg in addition to root_pkg. They are usually the
same. When using `zig test`, main_pkg is the user's source file and
root_pkg has the test runner.
* scanDecl no longer looks for test decls outside the package being
tested. honoring `--test-filter` is still TODO.
* test runner main function has a void return value rather than
`anyerror!void`
* Sema is improved to generate better AIR for for loops on slices.
* Sema: fix incorrect capacity calculation in zirBoolBr
* Sema: add compile errors for trying to use slice fields as an lvalue.
* Sema: fix type coercion for error unions
* Sema: fix analyzeVarRef generating garbage AIR
* C codegen: fix renderValue for error unions with 0 bit payload
* C codegen: implement function pointer calls
* CLI: fix usage text
Adds 4 new AIR instructions:
* slice_len, slice_ptr: to get the ptr and len fields of a slice.
* slice_elem_val, ptr_slice_elem_val: to get the element value of
a slice, and a pointer to a slice.
AstGen gains a new functionality:
* One of the unused flags of struct decls is now used to indicate
structs that are known to have non-zero size based on the AST alone.
Additionally: ZIR encoding for floats now supports float literals up to
f64, not only f32. This is because we no longer need a source location
for this instruction.
This commit changes the AIR file and the documentation of the memory
layout. The actual work of modifying the surrounding code (in Sema and
codegen) is not yet done.
AstGen had the then-else logic backwards for if expressions
on error unions. This commit fixes it.
Turns out AstGen only really needs `is_non_null` and `is_non_err`,
and does not need the `is_null` or `is_err` variants. So I removed the
`is_null{,_ptr}` and `is_err{,_ptr}` ZIR instructions (-4) and
added `is_non_err`, `is_non_err_ptr` ZIR instructions (+2) for
a total of (-2) ZIR instructions, giving us a tiny bit more headroom
within the 256 tag limit. This required swapping the order of
then/else blocks in a handful of cases, but ultimately means the
ZIR will be in the same as source order, which is convenient
when debugging.
AIR code on the other hand, gains the `is_non_err` and `is_non_err_ptr`
instructions.
Sema: fix logic in zirErrUnionCode and zirErrUnionCodePtr returning the
wrong result type.
* 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.
The Zig language specification will support identifiers and field access
in order to refer to which declaration to export with `@export`.
This commit implements the change in AstGen and updates the language
reference.
We've settled on the nomenclature for the artifacts the compiler
pipeline produces:
1. Tokens
2. AST (Abstract Syntax Tree)
3. ZIR (Zig Intermediate Representation)
4. AIR (Analyzed Intermediate Representation)
5. Machine Code
Renaming `ir` identifiers to `air` will come with the inevitable
air-memory-layout branch that I plan to start after the 0.8.0 release.
which can be either parent, func, or anon. Here's the enum reproduced in
the commit message for convenience:
```zig
pub const NameStrategy = enum(u2) {
/// Use the same name as the parent declaration name.
/// e.g. `const Foo = struct {...};`.
parent,
/// Use the name of the currently executing comptime function call,
/// with the current parameters. e.g. `ArrayList(i32)`.
func,
/// Create an anonymous name for this declaration.
/// Like this: "ParentDeclName_struct_69"
anon,
};
```
With this information in the ZIR, a future commit can improve the
names of structs, unions, enums, and opaques.
In order to accomplish this, the following ZIR instruction forms were
removed and replaced with Extended op codes:
* struct_decl
* struct_decl_packed
* struct_decl_extern
* union_decl
* union_decl_packed
* union_decl_extern
* enum_decl
* enum_decl_nonexhaustive
By being extended opcodes, one more u32 is needed, however we more than
make up for it by repurposing the 16 "small" bits to provide shorter
encodings for when decls_len == 0, fields_len == 0, a source node is not
provided, etc. There tends to be no downside, and in fact sometimes
upsides, to using an extended op code when there is a need for flag
bits, which is the case for all three of these. Likewise, the container
layout can be encoded in these bits rather than into the opcode.
The following 4 ZIR instructions were added, netting a total of 4 freed
up ZIR enum tags for future use:
* opaque_decl_anon
* opaque_decl_func
* error_set_decl_anon
* error_set_decl_func
This is so that opaques and error sets can have the same name hint as
structs, enums, and unions.
`std.builtin.ContainerLayout` gets an explicit integer tag type so that
it can be used inside packed structs.
This commit also makes `Module.Namespace` use a separate set for
anonymous decls, thus allowing anonymous decls to share the same
`Decl.name` as their owner `Decl` objects.
* Sema: implement global variables
- Improved global constants to stop needlessly creating a Var
structure; they can just store the value directly.
- This required making memory management a bit more sophisticated to
detect when a Decl owns the Namespace associated with it, for the
purposes of deinitialization.
* Decl.name and Namespace decl table keys no longer directly
reference ZIR; instead they have heap-duped names, so that deleted
decls, which no longer have any ZIR to reference for their names, can
be removed from the parent Namespace table.
- In the future I would like to explore going a different direction
with this, where the strings would still point to the ZIR however
they would be removed from their owner Namespace objects during the
update detection. The design principle here is that the existence
of incremental compilation as a feature should not incur any cost
for the use case when it is not used. In this example Decl names
could simply point to ZIR string table memory, and it is only
because of incremental compilation that we duplicate their names.
* AstGen: implement threadlocal variables
* CLI: call cleanExit after building a compilation so that in release
modes we don't bother freeing memory or closing file descriptors,
allowing the OS to do it more efficiently.
* Avoid calling `freeDecl` in the linker for unreferenced Decl objects.
* Fix CBE test case expecting the compile error to point to the wrong
column.
Now that they are lazy, they need to get analyzed in the correct
context, when requested.
This commit also hooks up std.builtin type values being resolved
properly. This is needed, for example, with the `@export` builtin
function, which occurs in start.zig, for `std.builtin.ExportOptions`.
The ZIR code uses the special `Ref.export_options` value, and semantic
analysis has to map this to the corresponding type from `std.builtin`.
This allows Sema to namespace them separately from function decls with
the same name. Ran into this in std.math.order conflicting with a test
with the same name.
