| Age | Commit message (Collapse) | Author | Lines |
|---|
|
|
|
Set writable and dead_on_unwind attributes for sret arguments
Set the `writable` and `dead_on_unwind` attributes for `sret` arguments. This allows call slot optimization to remove more memcpy's.
See https://llvm.org/docs/LangRef.html#parameter-attributes for the specification of these attributes. In short, the statement we're making here is that:
* The return slot is writable.
* The return slot will not be read if the function unwinds.
Fixes https://github.com/rust-lang/rust/issues/90595.
|
|
|
|
Stop using LLVM struct types for alloca
The alloca type has no semantic meaning, only the size (and alignment, but we specify it explicitly) matter. Using `[N x i8]` is a more direct way to specify that we want `N` bytes, and avoids relying on LLVM's struct layout. It is likely that a future LLVM version will change to an untyped alloca representation.
Split out from #121577.
r? `@ghost`
|
|
|
|
|
|
`OperandRef` does)
|
|
The actual ABI implication here is that in some cases the values
are required to be "consecutive", i.e. must either all be passed
in registers or all on stack (without padding).
Adjust the code to either use Uniform::new() or Uniform::consecutive()
depending on which behavior is needed.
Then, when lowering this in LLVM, skip the [1 x i128] to i128
simplification if is_consecutive is set. i128 is the only case
I'm aware of where this is problematic right now. If we find
other cases, we can extend this (either based on target information
or possibly just by not simplifying for is_consecutive entirely).
|
|
When passing a 16 (or higher) aligned struct by value on ppc64le,
it needs to be passed as an array of `i128` rather than an array
of `i64`. This will force the use of an even starting register.
For the case of a 16 byte struct with alignment 16 it is important
that `[1 x i128]` is used instead of `i128` -- apparently, the
latter will get treated similarly to `[2 x i64]`, not exhibiting
the correct ABI. Add a `force_array` flag to `Uniform` to support
this.
The relevant clang code can be found here:
https://github.com/llvm/llvm-project/blob/fe2119a7b08b6e468b2a67768904ea85b1bf0a45/clang/lib/CodeGen/Targets/PPC.cpp#L878-L884
https://github.com/llvm/llvm-project/blob/fe2119a7b08b6e468b2a67768904ea85b1bf0a45/clang/lib/CodeGen/Targets/PPC.cpp#L780-L784
I think the corresponding psABI wording is this:
> Fixed size aggregates and unions passed by value are mapped to as
> many doublewords of the parameter save area as the value uses in
> memory. Aggregrates and unions are aligned according to their
> alignment requirements. This may result in doublewords being
> skipped for alignment.
In particular the last sentence.
Fixes https://github.com/rust-lang/rust/issues/122767.
|
|
Previously, we did this slightly incorrectly for return values, and
didn't do it at all for arguments.
|
|
special case that's not present in Clang
Making the methods consistent doesn't require much justification. It's
required for us to generate correct code.
The special case was present near the end of `CastTarget::llvm_type`, and
resulted in the final integer component of the ABI type being shrunk to
the smallest integer that fits.
You can see this in action here (https://godbolt.org/z/Pe73cr91d),
where, for a struct with 5 u16 elements, rustc generates
`{ i64, i16 }`, while Clang generates `[2 x i64]`.
This special case was added a long time ago, when the function was
originally written [1]. That commit consolidated logic from many
backends, and in some of the code it deleted, sparc64 [2] and
powerpc64 [3] had similar special cases.
However, looking at Clang today, it doesn't have this special case for
sparc64 (https://godbolt.org/z/YaafvYWdf) or powerpc64
(https://godbolt.org/z/5c3YePTje), so this change just removes it.
[1]: https://github.com/rust-lang/rust/commit/f0636b61c7f84962a609e831760db9d77f4f5e14#diff-183c4dadf10704bd1f521b71f71d89bf755c9603a93f894d66c03bb1effc6021R231
[2]: https://github.com/rust-lang/rust/commit/f0636b61c7f84962a609e831760db9d77f4f5e14#diff-2d8f87ea6db6d7f0a6fbeb1d5549adc07e93331278d951a1e051a40f92914436L163-L166
[3]: https://github.com/rust-lang/rust/commit/f0636b61c7f84962a609e831760db9d77f4f5e14#diff-88af4a9df9ead503a5c7774a0455d270dea3ba60e9b0ec1ce550b4c53d3bce3bL172-L175
|
|
|
|
This avoids depending on LLVM's struct types to determine the size of
the byval/sret slot.
|
|
|
|
Currently, we assume that ScalarPair is always represented using
a two-element struct, both as an immediate value and when stored
in memory.
This currently works fairly well, but runs into problems with
https://github.com/rust-lang/rust/pull/116672, where a ScalarPair
involving an i128 type can no longer be represented as a two-element
struct in memory. For example, the tuple `(i32, i128)` needs to be
represented in-memory as `{ i32, [3 x i32], i128 }` to satisfy
alignment requirement. Using `{ i32, i128 }` instead will result in
the second element being stored at the wrong offset (prior to
LLVM 18).
Resolve this issue by no longer requiring that the immediate and
in-memory type for ScalarPair are the same. The in-memory type
will now look the same as for normal struct types (and will include
padding filler and similar), while the immediate type stays a
simple two-element struct type. This also means that booleans in
immediate ScalarPair are now represented as i1 rather than i8,
just like we do everywhere else.
The core change here is to llvm_type (which now treats ScalarPair
as a normal struct) and immediate_llvm_type (which returns the
two-element struct that llvm_type used to produce). The rest is
fixing things up to no longer assume these are the same. In
particular, this switches places that try to get pointers to the
ScalarPair elements to use byte-geps instead of struct-geps.
|
|
detects redundant imports that can be eliminated.
for #117772 :
In order to facilitate review and modification, split the checking code and
removing redundant imports code into two PR.
|
|
`x clippy compiler -Aclippy::all -Wclippy::needless_borrow --fix`.
Then I had to remove a few unnecessary parens and muts that were exposed
now.
|
|
|
|
|
|
Co-authored-by: Jubilee <46493976+workingjubilee@users.noreply.github.com>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
As experimentation in 115242 has shown looks better than `coldcc`.
And *don't* use a different convention for cold on Windows, because that actually ends up making things worse.
cc tracking issue 97544
|
|
Similar to prior support added for the mips430, avr, and x86 targets
this change implements the rough equivalent of clang's
[`__attribute__((interrupt))`][clang-attr] for riscv targets, enabling
e.g.
```rust
static mut CNT: usize = 0;
pub extern "riscv-interrupt-m" fn isr_m() {
unsafe {
CNT += 1;
}
}
```
to produce highly effective assembly like:
```asm
pub extern "riscv-interrupt-m" fn isr_m() {
420003a0: 1141 addi sp,sp,-16
unsafe {
CNT += 1;
420003a2: c62a sw a0,12(sp)
420003a4: c42e sw a1,8(sp)
420003a6: 3fc80537 lui a0,0x3fc80
420003aa: 63c52583 lw a1,1596(a0) # 3fc8063c <_ZN12esp_riscv_rt3CNT17hcec3e3a214887d53E.0>
420003ae: 0585 addi a1,a1,1
420003b0: 62b52e23 sw a1,1596(a0)
}
}
420003b4: 4532 lw a0,12(sp)
420003b6: 45a2 lw a1,8(sp)
420003b8: 0141 addi sp,sp,16
420003ba: 30200073 mret
```
(disassembly via `riscv64-unknown-elf-objdump -C -S --disassemble ./esp32c3-hal/target/riscv32imc-unknown-none-elf/release/examples/gpio_interrupt`)
This outcome is superior to hand-coded interrupt routines which, lacking
visibility into any non-assembly body of the interrupt handler, have to
be very conservative and save the [entire CPU state to the stack
frame][full-frame-save]. By instead asking LLVM to only save the
registers that it uses, we defer the decision to the tool with the best
context: it can more accurately account for the cost of spills if it
knows that every additional register used is already at the cost of an
implicit spill.
At the LLVM level, this is apparently [implemented by] marking every
register as "[callee-save]," matching the semantics of an interrupt
handler nicely (it has to leave the CPU state just as it found it after
its `{m|s}ret`).
This approach is not suitable for every interrupt handler, as it makes
no attempt to e.g. save the state in a user-accessible stack frame. For
a full discussion of those challenges and tradeoffs, please refer to
[the interrupt calling conventions RFC][rfc].
Inside rustc, this implementation differs from prior art because LLVM
does not expose the "all-saved" function flavor as a calling convention
directly, instead preferring to use an attribute that allows for
differentiating between "machine-mode" and "superivsor-mode" interrupts.
Finally, some effort has been made to guide those who may not yet be
aware of the differences between machine-mode and supervisor-mode
interrupts as to why no `riscv-interrupt` calling convention is exposed
through rustc, and similarly for why `riscv-interrupt-u` makes no
appearance (as it would complicate future LLVM upgrades).
[clang-attr]: https://clang.llvm.org/docs/AttributeReference.html#interrupt-risc-v
[full-frame-save]: https://github.com/esp-rs/esp-riscv-rt/blob/9281af2ecffe13e40992917316f36920c26acaf3/src/lib.rs#L440-L469
[implemented by]: https://github.com/llvm/llvm-project/blob/b7fb2a3fec7c187d58a6d338ab512d9173bca987/llvm/lib/Target/RISCV/RISCVRegisterInfo.cpp#L61-L67
[callee-save]: https://github.com/llvm/llvm-project/blob/973f1fe7a8591c7af148e573491ab68cc15b6ecf/llvm/lib/Target/RISCV/RISCVCallingConv.td#L30-L37
[rfc]: https://github.com/rust-lang/rfcs/pull/3246
|
|
|
|
|
|
|
|
|
|
This commit is aimed at making compiler generated entry functions
(Basically just C `main` right now) more generic so other targets can do
similar things for custom entry. This was initially implemented as part
of https://github.com/rust-lang/rust/pull/100316.
Currently, this moves the entry function name and Call convention to the
target spec.
Signed-off-by: Ayush Singh <ayushsingh1325@gmail.com>
|
|
Some codegen backends are not able to apply callsite attrs after the fact.
|
|
Enable eager checks for memory sanitizer
Fixes #99179
|
|
Because it's only needed for that variant. This shrinks the types and
clarifies the logic.
|
|
Because it's only ever set to `None` or `Some(Reg::i32())`.
|
|
Currently they try to be very precise. But they are wrong, i.e. they
don't match what's happening in the loop below. This code isn't hot
enough for it to matter that much.
|
|
|
|
|
|
Because `PassMode::Cast` is by far the largest variant, but is
relatively rare.
This requires making `PassMode` not impl `Copy`, and `Clone` is no
longer necessary. This causes lots of sigil adjusting, but nothing very
notable.
|
|
|
|
These intrinsics (and a few more, but there are the only ones
exposed by stdarch) require an elementtype attribute in LLVM 15.
|
|
This is no longer used only for debugging options (e.g. `-Zoutput-width`, `-Zallow-features`).
Rename it to be more clear.
|
|
The eventual goal is to try using this for things like the internal panicking stuff, to see whether it helps.
|
|
initialized scalars can special case them.
|
|
|
|
|
|
This should improve performance.
|
|
At opt-level=0, apply only ABI-affecting attributes to functions
This should provide a small perf improvement for debug builds,
and should more than cancel out the perf regression from adding noundef (https://github.com/rust-lang/rust/pull/93670#issuecomment-1038347581, #94106).
r? `@nikic`
|
