This can also be extended to ELF later as it means roughly the same thing there.
This addresses the main issue in #21721 but as I don't have a macOS machine to
do further testing on, I can't confirm whether zig cc is able to pass the entire
cgo test suite after this commit. It can, however, cross-compile a basic program
that uses cgo to x86_64-macos-none which previously failed due to lack of -x
support. Unlike previously, the resulting symbol table does not contain local
symbols (such as C static functions).
I believe this satisfies the related donor bounty: https://ziglang.org/news/second-donor-bounty
Currently zig fails to build while linking the system LLVM/C++ libraries
on my Chimera Linux system due to the fact that libc++.so is a linker
script with the following contents:
INPUT(libc++.so.1 -lc++abi -lunwind)
Prior to this commit, zig would try to convert "ambiguous names" in
linker scripts such as libc++.so.1 in this example into -lfoo style
flags. This fails in this case due to the so version number as zig
checks for exactly the .so suffix.
Furthermore, I do not think that this conversion is semantically correct
since converting libfoo.so to -lfoo could theoretically end up resulting
in libfoo.a getting linked which seems wrong when a different file is
specified in the linker script.
With this patch, this attempted conversion is removed. Instead, zig
always first checks if the exact file/path in the linker script exists
relative to the current working directory.
If the file is classified as a library (including versioned shared
objects such as libfoo.so.1), zig then falls back to checking if
the exact file/path in the linker script exists relative to each
directory in the library search path, selecting the first match or
erroring out if none is found.
This behavior fixes the regression that prevents building zig while
linking the system LLVM/C++ libraries on Chimera Linux.
Acts as a replacement for `addSharedLibrary` and `addStaticLibrary`, but
linking mode can be changed more easily in build.zig, for example:
In library:
```zig
const linkage = b.option(std.builtin.LinkMode, "linkage", "Link mode for a foo_bar library") orelse .static; // or other default
const lib = b.addLibrary(.{
.linkage = linkage,
.name = "foo_bar",
.root_module = mod,
});
```
In consumer:
```zig
const dep_foo_bar = b.dependency("foo_bar", .{
.target = target,
.optimize = optimize,
.linkage = .static // or dynamic
});
mod.linkLibrary(dep_foor_bar.artifact("foo_bar"));
```
It also matches nicely with `linkLibrary` name.
Signed-off-by: Eric Joldasov <bratishkaerik@landless-city.net>
crti.o/crtn.o is a legacy strategy for calling constructor functions
upon object loading that has been superseded by the
init_array/fini_array mechanism.
Zig code depends on neither, since the language intentionally has no way
to initialize data at runtime, but alas the Zig linker still must
support this feature since popular languages depend on it.
Anyway, the way it works is that crti.o has the machine code prelude of
two functions called _init and _fini, each in their own section with the
respective name. crtn.o has the machine code instructions comprising the
exitlude for each function. In between, objects use the .init and .fini
link section to populate the function body.
This function is then expected to be called upon object initialization
and deinitialization.
This mechanism is depended on by libc, for example musl and glibc, but
only for older ISAs. By the time the libcs gained support for newer
ISAs, they had moved on to the init_array/fini_array mechanism instead.
For the Zig linker, we are trying to move the linker towards
order-independent objects which is incompatible with the legacy
crti/crtn mechanism.
Therefore, this commit drops support entirely for crti/crtn mechanism,
which is necessary since the other commits in this branch make it
nondeterministic in which order the libc objects and the other link
inputs are sent to the linker.
The linker is still expected to produce a deterministic output, however,
by ignoring object input order for the purposes of symbol resolution.
fix calculation of alignment and size
include __tls_align and __tls_size globals along with __tls_base
include them only if the TLS segment is emitted
add missing reloc logic for memory_addr_tls_sleb
fix name of data segments to include only the prefix
Object being linked has neither functions nor globals named "foo" or
"bar" and so these names correctly fail to be exported when creating an
executable.
I intentionally simplified the target features functionality to use the
target features that are explicitly specified to the linker and ignore
the "tooling conventions"
this makes the wasm linker behave the same as ELF, COFF, and MachO.
this tests for importing a function table, but the example source does
not try to use an imported table, so it's a useless check. it's unclear
what the behavior is even supposed to do in this case.
the other two cases are left alone.
The purpose of this test is unclear. It checks for the existence of bss
section which is completely unnecessary since those zeroes can be
omitted from the binary.
Furthermore the code generated for __wasm_init_memory looks wrong.
Finally, the CheckObject DSL is brittle, it only checks for exact
matches of entire lines in an ad-hoc text format. Conclusion, it's a bad
test, delete it.
This is necessary since isGnuLibC() is true for hurd, so we need to be able to
represent a glibc version for it.
Also add an Os.TaggedVersionRange.gnuLibCVersion() convenience function.
According to a comment in mold, this is the expected (and desired)
condition by the linkers, except for some architectures (RISCV and
Loongarch) where this condition does not have to upheld.
If you follow the changes in this patch and in particular doc comments
I have linked the comment/code in mold that explains and implements
this.
I have also modified `testEhFrameRelocatable` test to now test both
cases such that `zig ld -r a.o b.o -o c.o` and `zig ld -r b.o a.o -o
d.o`. In both cases, `c.o` and `d.o` should produce valid object
files which was not the case before this patch.
The compiler defaults this value to off so that users whose system
shared libraries are all ELF files don't have to pay the cost of
checking every file to find out if it is a text file instead.
When a GNU ld script is encountered, the error message instructs users
about the CLI flag that will immediately solve their problem.
along with the relevant logic, making the libraries within subject to
the same search criteria as all the other libraries.
this unfortunately means doing file system access on all .so files when
targeting ELF to determine if they are linker scripts, however, I have a
plan to address this.
flush() must not do anything more than necessary. Determining the type
of input files must be done only once, before flush. Fortunately, we
don't even need any file system accesses to do this since that
information is statically known in most cases, and in the rest of the
cases can be determined by file extension alone.
This commit also updates the nearby code to conform to the convention
for error handling where there is exactly one error code to represent
the fact that error messages have already been emitted. This had the
side effect of improving the error message for a linker script parse
error.
"positionals" is not a linker concept; it is a command line interface
concept. Zig's linker implementation should not mention "positionals".
This commit deletes that array list in favor of directly making function
calls, eliminating that heap allocation during flush().
The compiler actually doesn't need any functional changes for this: Sema
does reification based on the tag indices of `std.builtin.Type` already!
So, no zig1.wasm update is necessary.
This change is necessary to disallow name clashes between fields and
decls on a type, which is a prerequisite of #9938.
These are fundamentally incapable of producing accurate information for reasons
I've laid out in #20771. Since our only use of these functions is to check that
object files have the correct machine type, and since #21020 made
`std.Target.to{Coff,Elf}Machine()` more accurate, just switch these checks over
to that and compare the machine type tags instead.
Closes#20771.
