AIR:
* div is renamed to div_trunc.
* Add div_float, div_floor, div_exact.
- Implemented in Sema and LLVM codegen. C backend has a stub.
Improvements to std.math.big.Int:
* Add `eqZero` function to `Mutable`.
* Fix incorrect results for `divFloor`.
Compiler-rt:
* Add muloti4 to the stage2 section.
* Introduce `memoized_calls` to `Module` which stores all the comptime
function calls that are cached. It is keyed on the `*Fn` and the
comptime arguments, but it does not yet properly detect comptime function
pointers and avoid memoizing in this case. So it will have false
positives for when a comptime function call mutates data through a
pointer parameter.
* Sema: Add a new helper function: `resolveConstMaybeUndefVal`
* Value: add `enumToInt` method and use it in `zirEnumToInt`. It is
also used by the hashing function.
* Value: fix representation of optionals to match error unions.
Previously it would not handle nested optionals correctly. Now it
matches the memory layout of error unions and supports nested
optionals properly. This required changes in all the backends for
generating optional constants.
* TypedValue gains `eql` and `hash` methods.
* Value: Implement hashing for floats, optionals, and enums.
Additionally, the zig type tag is added to the hash, where it was not
previously, so that values of differing types will get different
hashes.
* Value: rename `error_union` to `eu_payload` and clarify the intended
usage in the doc comments. The way error unions is represented with
Value is fixed to not have ambiguous values.
* Fix codegen for error union constants in all the backends.
* Implement the AIR instructions having to do with error unions in the
LLVM backend.
- This ensures we honor the user's integer size when performing wrapping operations.
- Also, instead of using ensureCapacity, we now use ensureUnusedCapacity.
This uses the same approach as error unions,
meaning it's a `WValue` with its tag set to `multi_value`.
The initial index of the multi_value will contain the null-tag, used to check if the value
is null or not. The other values will be the payload.
To support the `.?` shorthand syntax, we save the result from checking the null-tag
into a new local, which can then be loaded later in the block to either hit `unreachable` or
set the actual payload value.
Currently, it seems `.?` and `orelse unreachable` results in different AIR structure.
TODO: Is this expected?
- Some opcodes have the incorrect value set in std.
- Some opcodes were missing and have now been added to std.
- Adding wrapping operands for add,sub and mul.
- Implement intCast which either extends or shortens the type.
After this change, the frontend and backend cooperate to keep track of
which Decls are actually emitted into the machine code. When any backend
sees a `decl_ref` Value, it must mark the corresponding Decl `alive`
field to true.
This prevents unused comptime data from spilling into the output object
files. For example, if you do an `inline for` loop, previously, any
intermediate value calculations would have gone into the object file.
Now they are garbage collected immediately after the owner Decl has its
machine code generated.
In the frontend, when it is time to send a Decl to the linker, if it has
not been marked "alive" then it is deleted instead.
Additional improvements:
* Resolve type ABI layouts after successful semantic analysis of a
Decl. This is needed so that the backend has access to struct fields.
* Sema: fix incorrect logic in resolveMaybeUndefVal. It should return
"not comptime known" instead of a compile error for global variables.
* `Value.pointerDeref` now returns `null` in the case that the pointer
deref cannot happen at compile-time. This is true for global
variables, for example. Another example is if a comptime known
pointer has a hard coded address value.
* Binary arithmetic sets the requireRuntimeBlock source location to the
lhs_src or rhs_src as appropriate instead of on the operator node.
* Fix LLVM codegen for slice_elem_val which had the wrong logic for
when the operand was not a pointer.
As noted in the comment in the implementation of deleteUnusedDecl, a
future improvement will be to rework the frontend/linker interface to
remove the frontend's responsibility of calling allocateDeclIndexes.
I discovered some issues with the plan9 linker backend that are related
to this, and worked around them for now.
* AIR no longer has a `variables` array. Instead of the `varptr`
instruction, Sema emits a constant with a `decl_ref`.
* AIR no longer has a `ref` instruction. There is no longer any
instruction that takes a value and returns a pointer to it. If this
is desired, Sema must either create an anynomous Decl and return a
constant `decl_ref`, or in the case of a runtime value, emit an
`alloc` instruction, `store` the value to it, and then return the
`alloc`.
* The `ref_val` Value Tag is eliminated. `decl_ref` should be used
instead. Also added is `eu_payload_ptr` which points to the payload
of an error union, given an error union pointer.
In general, Sema should avoid calling `analyzeRef` if it can be helped.
For example in the case of field_val and elem_val, there should never be
a reason to create a temporary (alloc or decl). Recent previous commits
made progress along that front.
There is a new abstraction in Sema, which looks like this:
var anon_decl = try block.startAnonDecl();
defer anon_decl.deinit();
// here 'anon_decl.arena()` may be used
const decl = try anon_decl.finish(ty, val);
// decl is typically now used with `decl_ref`.
This pattern is used to upgrade `ref_val` usages to `decl_ref` usages.
Additional improvements:
* Sema: fix source location resolution for calling convention
expression.
* Sema: properly report "unable to resolve comptime value" for loads of
global variables. There is now a set of functions which can be
called if the callee wants to obtain the Value even if the tag is
`variable` (indicating comptime-known address but runtime-known value).
* Sema: `coerce` resolves builtin types before checking equality.
* Sema: fix `u1_type` missing from `addType`, making this type have a
slightly more efficient representation in AIR.
* LLVM backend: fix `genTypedValue` for tags `decl_ref` and `variable`
to properly do an LLVMConstBitCast.
* Remove unused parameter from `Value.toEnum`.
After this commit, some test cases are no longer passing. This is due to
the more principled approach to comptime references causing more
anonymous decls to get sent to the linker for codegen. However, in all
these cases the decls are not actually referenced by the runtime machine
code. A future commit in this branch will implement garbage collection
of decls so that unused decls do not get sent to the linker for codegen.
This will make the tests go back to passing.
* Add AIR instruction: struct_field_val
- This is part of an effort to eliminate the AIR instruction `ref`.
- It's implemented for C backend and LLVM backend so far.
* Rename `resolvePossiblyUndefinedValue` to `resolveMaybeUndefVal` just
to save some columns on long lines.
* Sema: add `fieldVal` alongside `fieldPtr` (renamed from
`namedFieldPtr`). This is part of an effort to eliminate the AIR
instruction `ref`. The idea is to avoid unnecessary loads, stores,
stack usage, and IR instructions, by paying a DRY cost.
LLVM backend improvements:
* internal linkage vs exported linkage is implemented, along with
aliases. There is an issue with incremental updates due to missing
LLVM API for deleting aliases; see the relevant comment in this commit.
- `updateDeclExports` is hooked up to the LLVM backend now.
* Fix usage of `Type.tag() == .noreturn` rather than calling `isNoReturn()`.
* Properly mark global variables as mutable/constant.
* Fix llvm type generation of function pointers
* Fix codegen for calls of function pointers
* Implement llvm type generation of error unions and error sets.
* Implement AIR instructions: addwrap, subwrap, mul, mulwrap, div,
bit_and, bool_and, bit_or, bool_or, xor, struct_field_ptr,
struct_field_val, unwrap_errunion_err, add for floats, sub for
floats.
After this commit, `zig test` on a file with `test "example" {}`
correctly generates and executes a test binary. However the
`test_functions` slice is undefined and just happens to be going into
the .bss section, causing the length to be 0. The next step towards
`zig test` will be replacing the `test_functions` Decl Value with the
set of test function pointers, before it is sent to linker/codegen.
This is an initial version, todo:
- Also make this work for u64 values, as the table must be indexed by u32.
- Add support for signed integers.
- Add support for enums.
* 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.
Now supports multiple items pointing to the same body. This is a common
pattern even when using a jump table, with multiple cases pointing to
the same block of code.
In the case of a range specified, the items are moved to branches in the
else body. A future improvement may make it possible to have jump table
items as well as ranges pointing to the same block of code.
- Get correct types in wasm backend.
- `arg` is already a `Ref`, therefore simply use `@intToEnum`.
- Fix regression in `zirBoolBr, where the order of insertion was incorrect.
- Update `fail()` to not require a `srcLoc`.
This brings it in line with other backends, and we were always passing 'node_offset = 0', anyway.
- Fix unused local due to change of architecture wrt function/decl generation.
- Replace all old instructions to indexes within the function signatures.
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.
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.
- 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
This will set us up to correctly retrieve the error local index and payload index
depending on that of the multi_value's index. As from now, the error will always use
the multi_value's index, and the payload will use the following locals.
- This currently uses the multi-value feature to return both the possible error, and its payload.
- Also genAlloc and the logic to allocate the locals itself have been seperated, so we can create more locals
whenever needed, and not only when `genAlloc` is called.
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.
This allows us to differentiate between regular locals and variables that create multiple locals
on the stack such as optionals and structs.
Now `struct_a = struct_b;` works and only updates a reference, rather than update all local's values.
Also created more test cases to test against this.
- When returning within a block, we must use an explicit return opcode. For now always emit the opcode when calling return, rather than using implicit return statements.
- Also added a more comprehensive test case to test for enum values using conditions
- This adds support for enum values using field indexes
- EmitConstant's signature was changed so it's easier to recursively call it using a different type (enum -> int type).
- Implemented initial support for bitcast which for now just returns the `WValue` of the operand.
Conflicts:
* doc/langref.html.in
* lib/std/enums.zig
* lib/std/fmt.zig
* lib/std/hash/auto_hash.zig
* lib/std/math.zig
* lib/std/mem.zig
* lib/std/meta.zig
* test/behavior/alignof.zig
* test/behavior/bitcast.zig
* test/behavior/bugs/1421.zig
* test/behavior/cast.zig
* test/behavior/ptrcast.zig
* test/behavior/type_info.zig
* test/behavior/vector.zig
Master branch added `try` to a bunch of testing function calls, and some
lines also had changed how to refer to the native architecture and other
`@import("builtin")` stuff.
