Add an option to allow the '-z notext' option to be passed to the linker
via. the compiler frontend, which is a flag that tells the linker that
relocations in read-only sections are permitted. Certain targets such as
Solana BPF rely on this flag.
Expose all linker options i.e. '-z nodelete', '-z now', '-z relro' in
the compiler frontend. Usage documentation has been updated accordingly.
Expose the '-z notext' flag in the standard library build runner.
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.
* test_functions: properly add dependencies of the array on test
functions and test names so that the order comes out correctly.
* fix lowering of struct literals to add parentheses around the type
name.
* omit const qualifier in slices because otherwise slices cannot be
reassigned even when they are local variables.
* special case pointer to functions and double pointer to functions in
renderTypeAndName. This code will need to be cleaned up but for now
it helps us make progress on other C backend stuff.
* fix slice element access to lower to `.ptr[` instead of `[`.
* airSliceElemVal: respect volatile slices
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 when running `zig test` with the C backend, it would return
`error.InvalidExe` because it would try to run the C code source file as
a binary. Now, by default, it will try to run it with
`zig run -lc foo.c` and this can be overridden with the standard
`--test-cmd` flags.
There is a table of `misc_failures` which previously did not allow
multiple errors for the same enum tag. Now it allows this by freeing the
previous compile error and replacing it with the new one. Typically this
will happen because multiple sub-Compilation objects fail with the same
problem, such as not being able to build glibc because of not having
LLVM extensions enabled.
The way `zig test` works is that it uses a stand-in
var test_functions: []const TestFn = undefined;
during semantic analysis, but then just before codegen, it swaps out the
value with a constant like this:
const test_functions: []const TestFn = .{foo, bar, baz, etc};
Before this commit, the `Module.Variable` associated with the stand-in
value was leaked; now it is properly cleaned up before being replaced.
The main problem that motivated these changes is that global constants
which are referenced by pointer would not be emitted into the binary.
This happened because `semaDecl` did not add `codegen_decl` tasks for
global constants, instead relying on the constant values being copied as
necessary. However when the global constants are referenced by pointer,
they need to be sent to the linker to be emitted.
After making global const arrays, structs, and unions get emitted, this
uncovered a latent issue: the anonymous decls that they referenced would
get garbage collected (via `deleteUnusedDecl`) even though they would
later be referenced by the global const.
In order to solve this problem, I introduced `anon_work_queue` which is
the same as `work_queue` except a lower priority. The `codegen_decl`
task for anon decls goes into the `anon_work_queue` ensuring that the
owner decl gets a chance to mark its anon decls as alive before they are
possibly deleted.
This caused a few regressions, which I made the judgement call to add
workarounds for. Two steps forward, one step back, is still progress.
The regressions were:
* Two behavior tests having to do with unions. These tests were
intentionally exercising the LLVM constant value lowering, however,
due to the bug with garbage collection that was fixed in this commit,
the LLVM code was not getting exercised, and union types/values were
not implemented correctly, due to me forgetting that LLVM does not
allow bitcasting aggregate values.
- This is worked around by allowing those 2 test cases to regress,
moving them to the "passing for stage1 only" section.
* The test-stage2 test cases (in test/cases/*) for non-LLVM backends
previously did not have any calls to lower struct values, but now
they do. The code that was there was just `@panic("TODO")`. I
replaced that code with a stub that generates the wrong value. This
is an intentional miscompilation that will obviously need to get
fixed before any struct behavior tests pass. None of the current
tests we have exercise loading any values from these global const
structs, so there is not a problem until we try to improve these
backends.
Previously, it would emit a ret_ptr AIR instruction but that is not
correct because such an instruction would reference the result pointer
of the caller function rather than the callee function.
Instead, we emit an alloc instruction in this case. `ret_load` already
handles inlining correctly.
* C pointer types always have allowzero set to true but they omit the
word allowzero when printed.
* Implement coercion from C pointers to other pointers.
* Implement in-memory coercion for slices and pointer-like optionals.
* Make slicing a C pointer drop the allowzero bit.
* Value representation for pointer-like optionals is now allowed to use
pointer tag values in addition to the `opt_payload` tag.
Switch prong values are fetched by index in semantic analysis by prong
offset, but these were computed as capture offset. This means that a switch
where the first prong does not capture and the second does, the switch_capture
zir instruction would be assigned switch_prong 0 instead of 1.
* AstGen: always use `typeof` and never `typeof_elem` on the
`switch_cond`/`switch_cond_ref` instruction because both variants
return a value and not a pointer.
- Delete the `typeof_elem` ZIR instruction since it is no longer
needed.
* Sema: validateUnionInit now recognizes a comptime mutable value and
no longer emits a compile error saying "cannot evaluate constant
expression"
- Still to-do is detecting comptime union values in a function that
is not being executed at compile-time.
- This is still to-do for structs too.
* Sema: when emitting a call AIR instruction, call resolveTypeLayout on
all the parameter types as well as the return type.
* `Type.structFieldOffset` now works for unions in addition to structs.
Over the last year of using std.log in practice, it has become clear to
me that having the current 8 distinct log levels does more harm than
good. It is too subjective which level a given message should have which
makes filtering based on log level weaker as not all messages will have
been assigned the log level one might expect.
Instead, more granular filtering should be achieved by leveraging the
logging scope feature. Filtering based on a combination of scope and log
level should be sufficiently powerful for all use-cases.
Note that the self hosted compiler has already limited itself to 4
distinct log levels for many months and implemented granular filtering
based on both log scope and level. This has worked very well in practice
while working on the self hosted compiler.
* without this, when an included relocatable references a common symbol
from another translation unit would not be correctly removed from
the unresolved lookup table triggering a misleading assertion down
the line
* assert upon removal that we indeed removed a ref instead of silently
ignoring in debug
* add test case that covers this issue
According to the documentation, `divTrunc` is "Truncated division.
Rounds toward zero". Lower it as a straightforward fdiv + trunc sequence
to make it behave as expected with mixed positive/negative operands.
Closes#10001
