The only allowed system libraries that we can link are libraries
that are part of the sysroot such as libc or WASI emulated
subcomponents. This is required as Wasm allows to defer symbol
resolution until load time.
For example, the following import in Zig
```zig
extern "wasi_snapshot_preview1" fn proc_exit() void;
```
would normally result in appending `-lwasi_snapshot_preview1` flag
to the linker line. However, for Wasm/WASI, the symbol is provided
at load rather than link time, therefore, the linker should not be
concerned with resolving the symbol. As a result, we should not
consider system libs by the Wasm linker.
* then, in `link/Wasm.zig` map `CRTFile` to full emulated libs name
* move logic for removing any mention of WASI snapshot
`wasi_snapshot_preview1` from `Compilation.zig` into `link/Wasm.zig`
Move parsing of system libs into `main.zig` next to where we decide
if we should link libC, and, if targeting WASI, if the specified
libname equals one of the emulated components, save it on the side
and remove it from the system libs. Then, build *only* those parts
of WASI libc that were preserved in the previous step.
This also fixes building of different crt1 bits needed to support
reactors and commands.
This replicates the expected behavior when using `clang` with
upstream `wasi-libc` sysroot: linking emulated subcomponents
such as process clocks or signals requires an explicit link flag
in the compiler invocation, for example:
```
zig cc -target wasm32-wasi -lwasi-emulated-process-clocks main.c -o main.wasm
```
- hash/eql functions moved into a Context object
- *Context functions pass an explicit context
- *Adapted functions pass specialized keys and contexts
- new getPtr() function returns a pointer to value
- remove functions renamed to fetchRemove
- new remove functions return bool
- removeAssertDiscard deleted, use assert(remove(...)) instead
- Keys and values are stored in separate arrays
- Entry is now {*K, *V}, the new KV is {K, V}
- BufSet/BufMap functions renamed to match other set/map types
- fixed iterating-while-modifying bug in src/link/C.zig
This refactor inserts an offset table into wasm's data section
where each offset points to the actual data region.
This means we can keep offset indexes consistant and do not
have to perform any computer to determine where in the data section
something like a static string exists. Instead during runtime
it will load the data offset onto the stack.
Now it builds and what remains in this branch is:
* fix the stage2 compiler regressions from this branch
* finish the rest of zig fmt test cases, get them passing
* Merge in Vexu's translate-c AST branch & fix translate-c regressions
The CLI gains -flto and -fno-lto options to override the default.
However, the cool thing about this is that the defaults are great! In
general when you use build-exe in release mode, Zig will enable LTO if
it would work and it would help.
zig cc supports detecting and honoring the -flto and -fno-lto flags as
well. The linkWithLld functions are improved to all be the same with
regards to copying the artifact instead of trying to pass single objects
through LLD with -r. There is possibly a future improvement here as
well; see the respective TODOs.
stage1 is updated to support outputting LLVM bitcode instead of machine
code when lto is enabled. This allows LLVM to optimize across the Zig and
C/C++ code boundary.
closes#2845
* rename is_compiler_rt_or_libc to skip_linker_dependencies
and set it to `true` for all sub-Compilations. I believe
this resolves the deadlock we were experiencing on Drone
CI and on some users' computers. I will remove the CI workaround in
a follow-up commit.
* enabling TSAN automatically causes the Compilation to link against
libc++ even if not requested, because TSAN depends on libc++.
* add -fno-rtti flags where appropriate when building TSAN objects.
Thanks Firefox317 for pointing this out.
* TSAN support: resolve all the undefined symbols. We are still seeing
a dependency on __gcc_personality_v0 but will resolve this one in a
follow-up commit.
* static libs do not try to build libc++ or libc++abi.
passthrough mode does not mean always exit - it just means to pass
through stdio and exit if the child process exits, without doing any
special error reporting.
* stage2: Make zig cc more verbose
Make `zig cc` print more info from Clang itself and from our own linker
invocation, this is needed for CMake to properly discover all the
include directories and library search paths.
Closes#7110
* Update `update_clang_options`
* Typo fixes
Co-authored-by: Jakub Konka <kubkon@jakubkonka.com>
* Move leb128 out of debug and remove trivial *mem functions as discussed in #5588
* Turns out one of the *Mem functions was used by MachO. Replaced with trivial use of FixedBufferStream.
* std.fs.Dir.readFile: add doc comments to explain what it means when
the returned slice has the same length as the supplied buffer.
* introduce readSmallFile / writeSmallFile to abstract over the
decision to use symlink or file contents to store data.
