This reverts commit 7cbd586ace46a8e8cebab660ebca3cfc049305d9.
This is causing a fail to build from source:
```
./lib/std/fmt.zig:492:17: error: cannot format optional without a specifier (i.e. {?} or {any})
@compileError("cannot format optional without a specifier (i.e. {?} or {any})");
^
./src/link/MachO/Atom.zig:544:26: note: called from here
log.debug(" RELA({s}) @ {x} => %{d} in object({d})", .{
^
```
I looked at the code to fix it but none of those args are optionals.
This is really minor but the issue this fixes is that if you copy-paste this output of `--show-builtin` into your `build.zig` for example then the formatter will format
```
pub const os = std.Target.Os{
.tag = .freestanding,
.version_range = .{ .none = {} }
};
```
to
```
pub const os = std.Target.Os{ .tag = .freestanding, .version_range = .{ .none = {} } };
```
which doesn't match the output.
With this comma, the output will stay the way it is after a `zig fmt`.
* make the setting in the linker backend be non-optional; by this time
all defaults are supposed to be resolved.
* integrate with `zig cc`
* change the CLI parsing to match C compiler parsing, allowing
`--compress-debug-sections` alone to choose a default encoding of
zlib.
Future improvement: make plain error notes actually render as notes
rather than errors, but keep them as errors for the case of
sub-compilation errors, e.g. when compiler-rt has compilation errors.
MachO linker now handles `-needed-l<name>`, `-needed_library=<name>`
and `-needed_framework=<name>`. While on macOS `-l` is equivalent
to `-needed-l`, and `-framework` to `-needed_framework`, it can be
used to the same effect as on Linux if combined with `-dead_strip_dylibs`.
This commit also adds handling for `-needed_library` which is macOS
specific flag only (in addition to `-needed-l`).
Finally, in order to leverage new linker testing harness, this commit
added ability to specify lowering to those flags via `build.zig`:
`linkSystemLibraryNeeded` (and related), and `linkFrameworkNeeded`.
Includes both traditiona and incremental codepaths with one caveat that
in incremental case, the requested size cannot be smaller than the
default padding size due to prealloc required due to incremental nature
of linking.
Also parse `-headerpad_max_install_names`, however, not actionable just yet -
missing implementation.
This adds clarification to the getGlobalSymbol doc comments,
as well as renames the `addExternFn` function for MachO to `getGlobalSymbol`.
This function will now be called from 'src/link.zig' as well.
Finally, this also enables compiling zig's libc using LLVM even though
the `fno-LLVM` flag is given.
Rather than checking if the user wants to use LLVM for the current compilation,
check for the existance of LLVM as part of the compiler. This is temporarily,
until other backends gain the ability to compiler LLVM themselves.
This means that when a user passed `-fno-LLVM` we will use the native
backend for the user's code, but use LLVM for compiler-rt.
This also fixes emitting names for symbols in the Wasm linker,
by deduplicating symbol names when multiple symbols point the same object.
If page aligned requested pagezero size is 0, skip generating
__PAGEZERO segment.
Add misc improvements to the pipeline, and correctly transfer the
requested __PAGEZERO size to the linker.
Pass `-pagezero_size` to the MachO linker. This is the final
"unsupported linker arg" that I could chase that CGo uses. After this
and #11874 we may be able to fail on an "unsupported linker arg" instead
of emiting a warning.
Test case:
zig=/code/zig/build/zig
CGO_ENABLED=1 GOOS=darwin GOARCH=amd64 CC="$zig cc -target x86_64-macos" CXX="$zig c++ -target x86_64-macos" go build -a -ldflags "-s -w" cgo.go
I compiled a trivial CGo program and executed it on an amd64 Darwin
host.
To be honest, I am not entirely sure what this is doing. This feels
right after reading what this argument does in LLVM sources, but I am by
no means qualified to make MachO pull requests. Will take feedback.
After doing performance testing, it seems that multi-compilation-unit
compiler-rt did not bring the performance improvements that we expected
it to. The idea is that it makes linking faster, however, it incurred a
cost in the frontend that was not offset by any gains in linking.
Furthermore, the single-object compiler-rt (with -ffunction-sections and
--gc-sections) ends up being fewer bytes on disk and so it's actually
the same or faster linking speed than the multi-compilation-unit
version.
So we are planning to keep using single-compilation-unit compiler-rt for
the foreseeable future, but may experiment with this again in the
future, in which case this commit can be reverted.
compiler_rt_lib and compiler_rt_obj are extracted from the generic
JobQueue into simple boolean flags, and then handled explicitly inside
performAllTheWork().
Introduced generic handling of allocation failure and made
setMiscFailure not return a possible error.
Building the compiler-rt static library now takes advantage of
Compilation's ThreadPool. This introduced a problem, however, because
now each of the object files of compiler-rt all perform AstGen for the
full standard library and compiler-rt files. Even though all of them end
up being cache hits except for the first ones, this is wasteful - O(N*M)
where N is number of compilation units inside compiler-rt and M is the
number of .zig files in the standard library and compiler-rt combined.
More importantly, however, it causes a deadlock, because each thread
interacts with a file system lock for doing AstGen on files, and threads
end up waiting for each other. This will need to be handled with a
process-level file caching system, or some other creative solution.
Note that the current documentation for the `-z noexecstack` is
incorrect. This indicates that an object *does not* require an
executable stack.
This is actually the default of LLD, and there has never been a way to
override this default by passing `-z execstack` to LLD.
This commit removes the redundant `-z noexecstack` option from
zig build-exe/build-lib/build-obj and ignores the option if passed
to zig cc for compatibility.
As far as I can tell, there is no reason for code to require an
executable stack. This option only exists because the stack was
originally executable by default and some programs came to depend
on that behavior. Instead, mprotect(2) may be used to make memory
pages executable.
Full RELRO is a hardening feature that makes it impossible to perform
certian attacks involving overwriting parts of the Global Offset Table
to invoke arbitrary code.
It requires all symbols to be resolved before execution of the program
starts which may have an impact on startup time. However most if
not all popular Linux distributions enable full RELRO by default for
all binaries and this does not seem to make a noticeable difference
in practice.
"Partial RELRO" is equivalent to `-z relro -z lazy`.
"Full RELRO" is equivalent to `-z relro -z now`.
LLD defaults to `-z relro -z lazy`, which means Zig's current `-z relro`
option has no effect on LLD's behavior.
The changes made by this commit are as follows:
- Document that `-z relro` is the default and add `-z norelro`.
- Pass `-z now` to LLD by default to enable full RELRO by default.
- Add `-z lazy` to disable passing `-z now`.
