Files
wasmtime/cranelift/filetests
Alex Crichton 830885383f Implement inline stack probes for AArch64 (#5353)
* Turn off probestack by default in Cranelift

The probestack feature is not implemented for the aarch64 and s390x
backends and currently the on-by-default status requires the aarch64 and
s390x implementations to be a stub. Turning off probestack by default
allows the s390x and aarch64 backends to panic with an error message to
avoid providing a false sense of security. When the probestack option is
implemented for all backends, however, it may be reasonable to
re-enable.

* aarch64: Improve codegen for AMode fallback

Currently the final fallback for finalizing an `AMode` will generate
both a constant-loading instruction as well as an `add` instruction to
the base register into the same temporary. This commit improves the
codegen by removing the `add` instruction and folding the final add into
the finalized `AMode`. This changes the `extendop` used but both
registers are 64-bit so shouldn't be affected by the extending
operation.

* aarch64: Implement inline stack probes

This commit implements inline stack probes for the aarch64 backend in
Cranelift. The support here is modeled after the x64 support where
unrolled probes are used up to a particular threshold after which a loop
is generated. The instructions here are similar in spirit to x64 except
that unlike x64 the stack pointer isn't modified during the unrolled
loop to avoid needing to re-adjust it back up at the end of the loop.

* Enable inline probestack for AArch64 and Riscv64

This commit enables inline probestacks for the AArch64 and Riscv64
architectures in the same manner that x86_64 has it enabled now. Some
more testing was additionally added since on Unix platforms we should be
guaranteed that Rust's stack overflow message is now printed too.

* Enable probestack for aarch64 in cranelift-fuzzgen

* Address review comments

* Remove implicit stack overflow traps from x64 backend

This commit removes implicit `StackOverflow` traps inserted by the x64
backend for stack-based operations. This was historically required when
stack overflow was detected with page faults but Wasmtime no longer
requires that since it's not suitable for wasm modules which call host
functions. Additionally no other backend implements this form of
implicit trap-code additions so this is intended to synchronize the
behavior of all the backends.

This fixes a test added prior for aarch64 to properly abort the process
instead of accidentally being caught by Wasmtime.

* Fix a style issue
2022-11-30 12:30:00 -06:00
..

filetests

Filetests is a crate that contains multiple test suites for testing various parts of cranelift. Each folder under cranelift/filetests/filetests is a different test suite that tests different parts.

Adding a runtest

One of the available testsuites is the "runtest" testsuite. Its goal is to compile some piece of clif code, run it and ensure that what comes out is what we expect.

To build a run test you can add the following to a file:

test interpret
test run
target x86_64
target aarch64
target s390x

function %band_f32(f32, f32) -> f32 {
block0(v0: f32, v1: f32):
    v2 = band v0, v1
    return v2
}
; run: %band_f32(0x0.5, 0x1.0) == 0x1.5

Since this is a run test for band we can put it in: runtests/band.clif. Once we have the file in the test suite we can run it by invoking: cargo run -- test filetests/filetests/runtests/band.clif from the cranelift directory.

The first lines tell clif-util what kind of tests we want to run on this file. test interpret invokes the interpreter and checks if the conditions in the ; run comments pass. test run does the same, but compiles the file and runs it as a native binary.

For more information about testing see testing.md.