This reverts commit 725267f7c20f0ba588b472048a8c1fe1a328c714, reversing
changes made to 2dae860de3494f97c9477af9282fe0131ff5c4cb.
This test is failing:
```zig
pub fn main() u8 {
var e = foo();
const i = e catch 69;
return i;
}
fn foo() anyerror!u8 {
return 5;
}
```
It's returning 69 instead of the expected value 5.
If a symbol is undefined after we tried resolving it in static and
dynamic libraries, and it is annotated with N_DESC_DISCARDED flag,
we simply ignore it rather than flagging an undefined symbol error.
If `r_extern == 0` (the relocation is non-extern, meaning it targets
a specific memory offset within the object's section) and if the
relocation type signifies that the relocation requires correction
for RIP such as SIGNED_1, then we need to subtract the correction,
here 1 for SIGNED_1, from the calculated addend value as it's
implicitly included.
- This implements the required codegen for decl types such as pointers, arrays, structs and more.
- Wasm's start function can now use both a 'u8' and 'void' as return type. This will help us with writing tests
using the stage2 testing backend. (Until all tests of behavioural tests pass).
- Now correctly generates relocations for function pointers.
- Also implements unwrapping error union error, as well as return pointers.
The function table contains all function pointers that are called
by using call_indirect. During codegen, we create a relocation
where the linker will resolve the correct index into the table and stores
this value within the data section at the location of the pointer.
This contains a few additions:
- Proper stack pointer calculation keeping alignment in mind.
- Setting up memory layout (including user flags).
- Export or import memory
- Handle 'easy' linker tasks during incremental compilation, while offloading
heavy-tracking/computation tasks to `flush()`
- This architecture allows us to easily integrate with the rest of 'zwld' to
implement linking stage2 code with external object files.
We now resolve relocations for globals, memory addresses and function indexes.
Besides above, we now also emit imported functions correctly and create a
corresponding undefined symbol for it, where as we create a defined symbol
for all other cases.
TODO: Make incrememental compilation work again with new linker infrastructure
- Converts previous `DeclBlock` into `Atom`'s to also make them compatible when
the rest of zlwd gets upstreamed and we can link with other object files.
- Resolves function signatures and removes any duplicates, saving us a lot of
potential bytes for larger projects.
- We now create symbols for each decl of the respective type
- We can now (but not implemented yet) perform proper relocations.
- Having symbols and segment_info allows us to create an object file
for wasm.
Since we are already detecting the path to the native SDK,
if available, also fetch SDK's version and route that to the linker.
The linker can then use it to correctly populate LC_BUILD_VERSION
load command.
Due to a deficiency in LLD, we need to special-case BPF to a simple
file copy when generating relocatables. Normally, we would expect
`lld -r` to work. However, because LLD wants to resolve BPF relocations
which it shouldn't, it fails before even generating the relocatable.
Co-authored-by: Matthew Knight <mattnite@protonmail.com>
In 7e23b3245a9bf6e002009e6c18c10a9995671afa I made -O flags to the
linker emit a warning that the argument does nothing. That was not
correct however; LLD does have some logic that does different things
depending on -O0, -O1, and -O2. It defaults to -O1, and it does less
optimizations with -O0 and more with -O2.
With this commit, e.g. `-Wl,-O1` is supported by the `zig cc` frontend,
and by default we pass `-O0` to LLD in debug mode, and `-O3` in release
modes.
I also fixed a bug in the LLD ELF linker line which was incorrectly
passing `-O` flags instead of `--lto-O` flags for LTO.
* Improve the logic for determining whether emitting an import lib is
eligible, and improve the error message when the user provides
contradictory arguments.
* Integrate with the EmitLoc / Emit system that already exists, and use
the `-femit-implib[=path]`/`-fno-emit-implib` convention that already
exists.
* Proper integration with the caching system.
* CLI: fix bug in error reporting for resolving EmitLoc values for
other parameters.
This mechanism for sending arbitrary linker args to LLD has no place in
the Zig frontend, because our goal is for the frontend to understand all
the arguments and not treat linker args like a black box.
For example we have self-hosted linking in addition to LLD, so we want to
have the options make sense to both linking codepaths, not just the LLD one.
Passing -O linker args will now result in a warning that the arg does
nothing.
Handle clang's linker flag `-weak_framework` as a standard framework to
link. This requires further investigation especially to do with weak
imports and how to tie one with the other.
* Introduce a mechanism into Sema for emitting a compile error when an
integer is too big and we need it to fit into a usize.
* Add `@intCast` where necessary
* link/MachO: fix an unnecessary allocation when all that was happening
was appending zeroes to an ArrayList.
* Add `error.Overflow` as a possible error to some codepaths, allowing
usage of `math.intCast`.
closes#9710
The self-hosted wasm linker now emits a mutable global.
This entry represents the stack pointer, which has an initial value of offset table size + data size + stack size.
Stack size can either be set by the user, or has the default of a single wasm page (64KiB).
After this change, the default for dynamic libraries (`-l` or
`--library`) is to only link them if they end up being actually used.
With the Zig CLI, the new options `-needed-l` or `--needed-library` can
be used to force link against a dynamic library.
With `zig cc`, this behavior can be overridden with `-Wl,--no-as-needed`
(and restored with `-Wl,--as-needed`).
Closes#10164
Previously, we have confused callee-saved with caller-saved registers
(the actual register sets were swapped). This commit fixes that
for both `.x86` and `.x86_64` native backends.
This commit also fixes the register allocation logic in `genBinMathOp`
for `.x86_64` native backend where in a situation such that we require
to spill a register, we would end up spilling the register that is
already involved in the instruction as the other operand. In such a
case, we make a note of this and spill a subsequent register instead.
* wasm: Move wasm's codegen to arch/wasm/CodeGen.zig
* wasm: Define Wasm's Mir
This declares the initial most-used instructions for wasm as
well as the data that represents them.
TODO: Add binary operand opcodes.
By re-using the wasm opcode values, we can emit each opcode very easily
by simply using `@enumToInt()`. However, this poses a possible problem:
If we use all of wasm's opcodes, it leaves us no room to use synthetic opcodes such as debugging instructions.
We could use reserved opcodes, but the wasm spec may use them at some point.
TODO: Check if we should perhaps use a 16bit tag where the highest bits are used for synthetic opcodes.
* wasm: Define basic Emit structure
* wasm: Implement corresponding Emit functions for MIR
* wasm: Initial lowering to MIR
- This implements lowering to MIR from AIR for storing and loading of locals
as well as emitting immediates.
- Relocating function indexes has been simplified a lot as well as we no
longer need to patch offsets and we write a relocatable value instead.
- Locals are now emitted at the beginning of the function section entry
meaning all offsets we generate are stable.
* wasm: Lower all AIR instructions to MIR
* wasm: Implement remaining MIR instructions
* wasm: Fix function relocations
* wasm: Get all tests working
* wasm: Make `Data` 4 bytes instead of 8.
- 64bit immediates are now stored in 2 seperate u32's.
- 64bit floats are now stored in 2 seperate u32's.
- `mem_arg` is now stored as a seperate payload in extra.
1. Changed Zig pointers to functions to be typedef'd so then we can
treat them the same as other types.
2. Distinguished between const slices (zig_L prefix) and mut slices
(zig_M prefix).
3. Changed lowering of Zig "const pointers" (e.g. *const u8) to to C
"pointers to const" (e.g. const char *) rather than C "const
pointers" (e.g. char * const)
4. Ensured that all typedefs are "linked" even if the decl doesn't
require any forward declarations
5. Added test that exercises function pointer type rendering
6. Changed .slice_ptr instruction to allocate pointer local rather than
a uintptr_t local
This effectively allows us to compile
```zig
pub fn main() void {}
```
which then calls into `std.start`.
Changes required to make this happen:
* handle signed int to immediate in x86_64 and aarch64 codegen
* ensure that on arm64 macOS, `.x19` is a caller-preserved register -
I'm not sure about that one at all and would like to brainstorm it
with anyone interested and especially Joachim.
* finally, fix a bug in the linker - mark new got entry as dirty upon
atom growth.
--import-memory import memory from the environment
--initial-memory=[bytes] initial size of the linear memory
--max-memory=[bytes] maximum size of the linear memory
--global-base=[addr] where to start to place global data
See #8633
