* use a set instead of a list
* use of this flag currently requires LLD
* add documentation
* make it only a zig cc compatibility flag for now because I personally
think this is an anti-feature.
Also clean up parsing of linker args - reuse `ArgsIterator`.
In MachO, ensure we add every symbol marked with `-u` as undefined
before proceeding with symbol resolution. Additionally, ensure those
symbols are never garbage collected.
MachO entry_in_dylib test: pass `-u _my_main` when linking executable
so that it is not incorrectly garbage collected by the linker.
Ideally, we would just do an atomic rename, but so far I had no
luck. I have also tried marking the file to delete-on-close but
then we cannot use it to spawn the process. So for now, let's just
put a copy in `zig-cache` and let the user decide when to recycle
the cache dir.
In Linux when interacting with the virtual file system when writing
in invalid value to a file the OS will return errno 22 (INVAL).
Instead of triggering an unreachable, this change now returns a
newly introduced error.InvalidArgument.
In Linux when writing to various files in the virtual file system,
for example /sys/fs/cgroup, if you write an invalid value to a file
you'll get errno 16.
This change allows for these specific cases to be caught instead of
being lumped together in UnexpectedError.
Tested by: created a "hello world" C file and compiled with:
zig cc -v main.c -Wl,--sort-section=name -o main
... and verified the `--sort-section=name` is passed to ld.lld.
Refs https://github.com/zigchroot/zig-chroot/issues/1
This implements the `__wasm_call_ctors` symbol. This symbol is
automatically referenced by libc to initialize its constructors.
We first retrieve all constructors from each object file, and then
create a function body that calls each constructor based on its
priority. Constructors are not allowed to have any parameters, but are
allowed to have a return type. When a return type does exist, we simply
drop its value from the stack after calling the constructor to ensure
we pass the stack validator.
Using zig cc with CMake on Windows was failing during compiler
detection. -nostdinc was causing the crt not to be linked, and Coff/lld.zig
assumed that wWinMainCRTStartup would be present in this case.
-nostdlib did not prevent the default behaviour of linking libc++ when
zig c++ was used. This caused libc++ to be built when CMake ran
ABI detection using zig c++, which fails as libcxxabi cannot compile
under MSVC.
- Change the behaviour of COFF -nostdinc to set /entry to the function that the
default CRT method for the specified subsystem would have called.
- Fix -ENTRY being passed twice if it was specified explicitly and -nostdlib was present.
- Add support for /pdb, /version, /implib, and /subsystem as linker args (passed by CMake)
- Remove -Ddisable-zstd, no longer needed
- Add -Ddisable-libcpp for use when bootstrapping on msvc
- add support for passing through .def files to the linker,
required for building libLTO.dll in LLVM
- fixup libcpp linking conditionals
- add option to skip linking zstd for use in bootstrapping (when
building against an LLVM with LLVM_ENABLE_ZSTD=OFF)
In #1622, when targeting WebAsembly, the --allow-undefined flag
became unconditionally added to the linker.
This is not always desirable.
First, this is error prone. Code with references to unkown symbols
will link just fine, but then fail at run-time.
This behavior is inconsistent with all other targets.
For freestanding wasm applications, and applications that only use
WASI, undefined references are better reported at compile-time.
This behavior is also inconsistent with clang itself. Autoconf and
cmake scripts checking for function presence think that all tested
functions exist, but then resulting application cannot run.
For example, this is one of the reasons compilation of Ruby 3.2.0
to WASI fails with zig cc, while it works out of the box with clang.
But all applications checking for symbol existence before compilation
are affected.
This reverts the behavior to the one Zig had before #1622, and
introduces an `import_symbols` flag to ignore undefined symbols,
assuming that the webassembly runtime will define them.
