Cmake by default adds the `/RTC1` compiler flag for debug builds.
However, this causes C code that conforms to the C standard and has
well-defined behavior to trap. Here I've updated CMAKE to use the more
lenient `/RTCs` by default which removes the uninitialized variable checks
but keeps the stack error checks.
I'm not convinced that some of the possibilities that these regexes allowed are real. I've literally never seen or heard of "armhfel", nor of "thumb" ever showing up in `uname -m`, etc.
Each target can opt into different sets of legalize features.
By performing these transformations before liveness, instructions
that become unreferenced will have up-to-date liveness information.
Nothing interesting here; literally just the bare minimum so I can work on this
on and off in a branch without worrying about merge conflicts in the non-backend
code.
Textual PTX is just assembly language like any other. And if we do ever add
support for emitting PTX object files after reverse engineering the bytecode
format, we'd be emitting ELF files like the CUDA toolchain. So there's really no
need for a special ObjectFormat tag here, nor linker code that treats it as a
distinct format.
This allows emitting object files for s390x-zos (GOFF) and powerpc(64)-aix
(XCOFF).
Note that GOFF emission in LLVM is still being worked on upstream for LLVM 21;
the resulting object files are useless right now. Also, -fstrip is required, or
LLVM will SIGSEGV during DWARF emission.
We build zig2.c and compiler_rt.c with -O0 but then proceed to link with -O3.
So zig2.o and compiler_rt.o will have references to ubsan-rt symbols, but the
-O3 causes the compiler to not link ubsan-rt. We don't actually need the safety
here, so just explicitly disable ubsan.
The goals of this branch are to:
* compile faster when using the wasm linker and backend
* enable saving compiler state by directly copying in-memory linker
state to disk.
* more efficient compiler memory utilization
* introduce integer type safety to wasm linker code
* generate better WebAssembly code
* fully participate in incremental compilation
* do as much work as possible outside of flush(), while continuing to do
linker garbage collection.
* avoid unnecessary heap allocations
* avoid unnecessary indirect function calls
In order to accomplish this goals, this removes the ZigObject
abstraction, as well as Symbol and Atom. These abstractions resulted
in overly generic code, doing unnecessary work, and needless
complications that simply go away by creating a better in-memory data
model and emitting more things lazily.
For example, this makes wasm codegen emit MIR which is then lowered to
wasm code during linking, with optimal function indexes etc, or
relocations are emitted if outputting an object. Previously, this would
always emit relocations, which are fully unnecessary when emitting an
executable, and required all function calls to use the maximum size LEB
encoding.
This branch introduces the concept of the "prelink" phase which occurs
after all object files have been parsed, but before any Zcu updates are
sent to the linker. This allows the linker to fully parse all objects
into a compact memory model, which is guaranteed to be complete when Zcu
code is generated.
This commit is not a complete implementation of all these goals; it is
not even passing semantic analysis.
Removes the `files` field from the Wasm linker, storing the ZigObject
as its own field instead using a tagged union.
This removes a layer of indirection when accessing the ZigObject, and
untangles logic so that we can introduce a "pre-link" phase that
prepares the linker state to handle only incremental updates to the
ZigObject and then minimize logic inside flush().
Furthermore, don't make array elements store their own indexes, that's
always a waste.
Flattens some of the file system hierarchy and unifies variable names
for easier refactoring.
Introduces type safety for optional object indexes.
`check_pie_supported` only uses the `OUTPUT_VARIABLE` to to signify errors
if PIE is actually supported is signaled by `CMAKE_<lang>_LINK_PIE_SUPPORTED`.
Checking if `OUTPUT_VARIABLE` is empty is not enough either since the check
is bypassed if its results are cached but the output variable is not cached.
Most of the required renames here are net wins for readaibility, I'd
say. The ones in `arch` are a little more verbose, but I think better. I
didn't bother renaming the non-conflicting functions in
`arch/arm/bits.zig` and `arch/aarch64/bits.zig`, since these backends
are pretty bit-rotted anyway AIUI.
