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.
* AstGen: Move `refToIndex` and `indexToRef` to Zir
* ZIR: the switch_block_*_* instruction tags are collapsed into one
switch_block tag which uses 4 bits for flags, and reduces the
scalar_cases_len field from 32 to 28 bits.
This freed up more ZIR tags, 2 of which are now used for
`switch_cond` and `switch_cond_ref` for producing the switch
condition value. For example, for union values it returns the
corresponding enum value.
* switching with multiple cases and ranges is not yet supported because
I want to change the ZIR encoding to store index pointers into the
extra array rather than storing prong indexes. This will avoid O(N^2)
iteration over prongs.
* AstGen now adds a `switch_cond` on the operand and then passes the
result of that to the `switch_block` instruction.
* Sema: partially implement `switch_capture_*` instructions.
* Sema: `unionToTag` notices if the enum type has only one possible value.
* 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.
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.
* less branching by passing parameters in the main op code switch.
* properly pass the target when asking the type system for int info.
* handle u8, i16, etc when it is represented using
int_unsigned/int_signed tag.
* compile error instead of assertion failure for unimplemented cases
(greater than 64 bits integer).
* control flow cleanups
* zig.h: expand macros into inline functions
* reduce the complexity of the test case by making it one test case
that calls multiple functions. Also fix the problem of c_int max
value mismatch between host and target.
* Inferred error sets are stored in the return Type of the function,
owned by the Module.Fn. So it cleans up that memory in deinit().
* Sema: update the inferred error set in zirRetErrValue
- Update relevant code in wrapErrorUnion
* C backend: improve some some instructions to take advantage of
liveness analysis to avoid being emitted when unused.
* C backend: when an error union has a payload type with no runtime
bits, emit the error union as the same type as the error set.
* 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.
It now displays the byte with proper printability handling. This makes
the relevant compile error test case no longer a regression in quality
from stage1 to stage2.
In order for this test to pass, the host linking/start code needs to
support explicitly setting the stack size. Zig defaults to 16 MiB stack
size, which is enough to pass the test in Debug builds, however, most
operating systems do not honor the stack size we request for and give a
smaller amount.
Eventually the goal is to pass this test on all hosts.
* Do not report export collision errors until the very end, because it
is possible, during an update, for a new export to be added before an
old one is semantically analyzed to be deleted. In such a case there
should be no compile error.
- Likewise we defer emitting exports until the end when we know for
sure what will happen.
* Sema: Fix not adding a Decl dependency on imported files.
* Sema: Properly add Decl dependencies for all identifier and namespace
lookups.
* After semantic analysis for a Decl, if it is still marked as
`in_progress`, change it to `dependency_failure` because if the Decl
itself failed, it would have already been changed during the call to
add the compile error.
* 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
Decl objects need to know whether they are the owner of the Type/Value
associated with them, in order to decide whether to destroy the
associated Namespace, Fn, or Var when cleaning up.
* 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.
There were several problems, all fixed:
* AstGen was storing field names as references to the original
source code bytes. However, that data would be destroyed when the
source file is updated. Now, it correctly stores the field names in
the Decl arena for the enum. The same fix applies to error set field
names.
* Sema was missing a memset inside `analyzeSwitch`, leaving the "seen
enum fields" array with undefined memory. Now that they are all
properly set to null, the validation works.
* Moved the "enum declared here" note to the end. It looked weird
interrupting the notes for which enum values were missing.
Before, incremental compilation would crash when trying to emit compile
errors for the update after introducing a parse error.
Parse errors are handled by not invalidating any existing semantic
analysis. However, only the parse error must be reported, with all the
other errors suppressed. Once the parse error is fixed, the new file can
be treated as an update to the previously-succeeded update.
* `analyzeContainer` now has an `outdated_decls` set as well as
`deleted_decls`. Instead of queuing up outdated Decls for re-analysis
right away, they are added to this new set. When processing the
`deleted_decls` set, we remove deleted Decls from the
`outdated_decls` set, to avoid deleted Decl pointers from being in
the work_queue. Only after processing the deleted decls do we add
analyze_decl work items to the queue.
* Module.deletion_set is now an `AutoArrayHashMap` rather than `ArrayList`.
`declareDeclDependency` will now remove a Decl from it as appropriate.
When processing the `deletion_set` in `Compilation.performAllTheWork`,
it now assumes all Decl in the set are to be deleted.
* Fix crash when handling parse errors. Currently we unload the
`ast.Tree` if any parse errors occur. Previously the code emitted a
LazySrcLoc pointing to a token index, but then when we try to resolve
the token index to a byte offset to create a compile error message,
the ast.Tree` would be unloaded. Now we use
`LazySrcLoc.byte_abs` instead of `token_abs` so the error message can
be created even with the `ast.Tree` unloaded.
Together, these changes solve a crash that happened with incremental
compilation when Decls were added and removed in some combinations.
Introduce `ResultLoc.none_or_ref` which is used by field access
expressions to avoid unnecessary loads when the field access itself
will do the load. This turns:
```zig
p.y - p.x - p.x
```
from
```zir
%14 = load(%4) node_offset:8:12
%15 = field_val(%14, "y") node_offset:8:13
%16 = load(%4) node_offset:8:18
%17 = field_val(%16, "x") node_offset:8:19
%18 = sub(%15, %17) node_offset:8:16
%19 = load(%4) node_offset:8:24
%20 = field_val(%19, "x") node_offset:8:25
```
to
```zir
%14 = field_val(%4, "y") node_offset:8:13
%15 = field_val(%4, "x") node_offset:8:19
%16 = sub(%14, %15) node_offset:8:16
%17 = field_val(%4, "x") node_offset:8:25
```
Much more compact. This requires `Sema.zirFieldVal` to support both
pointers and non-pointers.
C backend: Implement typedefs for struct types, as well as the following
TZIR instructions:
* mul
* mulwrap
* addwrap
* subwrap
* ref
* struct_field_ptr
Note that add, addwrap, sub, subwrap, mul, mulwrap instructions are all
incorrect currently and need to be updated to properly handle wrapping
and non wrapping for signed and unsigned.
C backend: change indentation delta to 1, to make the output smaller and
to process fewer bytes.
I promise I will add a test case as soon as I fix those warnings that
are being printed for my test case.
GenZir struct now has rl_ty_inst field which tracks the result location
type (if any) a block expects all of its results to be coerced to.
Remove a redundant coercion on const local initialization with a
specified type.
Switch expressions, during elision of store_to_block_ptr instructions,
now re-purpose them to be type coercion when the block has a type in the
result location.
* comment out the failing stage2 test cases
(so that we can uncomment the ones that are newly passing with
further commits)
* Sema: implement negate, negatewrap
* astgen: implement field access, multiline string literals, and
character literals
* Module: when resolving an AST node into a byte offset, use the
main_tokens array, not the firstToken function
