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Merge #1228
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1228: Singlepass cleanup: Resolve several FIXMEs and remove protect_unix. r=losfair a=losfair



Co-authored-by: losfair <[email protected]>
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bors[bot] and losfair authored Feb 17, 2020
2 parents a21cf6d + b1e2a7f commit 5832b48
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1 change: 1 addition & 0 deletions CHANGELOG.md
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Expand Up @@ -2,6 +2,7 @@

## **[Unreleased]**

- [#1228](https://github.com/wasmerio/wasmer/pull/1228) Singlepass cleanup: Resolve several FIXMEs and remove protect_unix.
- [#1218](https://github.com/wasmerio/wasmer/pull/1218) Enable Cranelift verifier in debug mode. Fix bug with table indices being the wrong type.
- [#787](https://github.com/wasmerio/wasmer/pull/787) New crate `wasmer-interface-types` to implement WebAssembly Interface Types.
- [#1213](https://github.com/wasmerio/wasmer/pull/1213) Fixed WASI `fdstat` to detect `isatty` properly.
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71 changes: 31 additions & 40 deletions lib/singlepass-backend/src/codegen_x64.rs
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Expand Up @@ -3,7 +3,6 @@

use crate::emitter_x64::*;
use crate::machine::*;
use crate::protect_unix;
#[cfg(target_arch = "aarch64")]
use dynasmrt::aarch64::Assembler;
#[cfg(target_arch = "x86_64")]
Expand All @@ -28,7 +27,7 @@ use wasmer_runtime_core::{
},
cache::{Artifact, Error as CacheError},
codegen::*,
fault::raw::register_preservation_trampoline,
fault::{self, raw::register_preservation_trampoline},
loader::CodeMemory,
memory::MemoryType,
module::{ModuleInfo, ModuleInner},
Expand Down Expand Up @@ -369,6 +368,11 @@ impl RunnableModule for X64ExecutionContext {
}

fn get_trampoline(&self, _: &ModuleInfo, sig_index: SigIndex) -> Option<Wasm> {
// Correctly unwinding from `catch_unsafe_unwind` on hardware exceptions depends
// on the signal handlers being installed. Here we call `ensure_sighandler` "statically"
// outside `invoke()`.
fault::ensure_sighandler();

unsafe extern "C" fn invoke(
_trampoline: Trampoline,
ctx: *mut vm::Ctx,
Expand All @@ -383,8 +387,9 @@ impl RunnableModule for X64ExecutionContext {
let args =
slice::from_raw_parts(args, num_params_plus_one.unwrap().as_ptr() as usize - 1);

let ret = match protect_unix::call_protected(
let ret = match fault::catch_unsafe_unwind(
|| {
// Puts the arguments onto the stack and calls Wasm entry.
#[cfg(target_arch = "x86_64")]
{
let args_reverse: SmallVec<[u64; 8]> = args.iter().cloned().rev().collect();
Expand All @@ -395,6 +400,9 @@ impl RunnableModule for X64ExecutionContext {
func.as_ptr(),
)
}

// FIXME: Currently we are doing a hack here to convert between native aarch64 and
// "emulated" x86 ABIs. Ideally, this should be done using handwritten assembly.
#[cfg(target_arch = "aarch64")]
{
struct CallCtx<'a> {
Expand Down Expand Up @@ -519,7 +527,7 @@ impl RunnableModule for X64ExecutionContext {
true
}
Err(err) => {
*error_out = Some(err.0);
*error_out = Some(err);
false
}
};
Expand All @@ -545,8 +553,7 @@ impl RunnableModule for X64ExecutionContext {
}

unsafe fn do_early_trap(&self, data: Box<dyn Any + Send>) -> ! {
protect_unix::TRAP_EARLY_DATA.with(|x| x.set(Some(data)));
protect_unix::trigger_trap();
fault::begin_unsafe_unwind(data);
}

fn get_code(&self) -> Option<&[u8]> {
Expand Down Expand Up @@ -1686,14 +1693,11 @@ impl X64FunctionCode {
Location::GPR(GPR::RSP),
);

// FIXME: Possible dynasm bug. This is a workaround.
// Using RSP as the source/destination operand of a `mov` instruction produces invalid code.
a.emit_mov(Size::S64, Location::GPR(GPR::RSP), Location::GPR(GPR::RCX));
for (i, r) in used_xmms.iter().enumerate() {
a.emit_mov(
Size::S64,
Location::XMM(*r),
Location::Memory(GPR::RCX, (i * 8) as i32),
Location::Memory(GPR::RSP, (i * 8) as i32),
);
}
for r in used_xmms.iter().rev() {
Expand Down Expand Up @@ -1771,37 +1775,26 @@ impl X64FunctionCode {
}
}
match *param {
// Dynasm bug: RSP in memory operand does not work
Location::Imm64(_) | Location::XMM(_) => {
a.emit_mov(
Size::S64,
Location::GPR(GPR::RAX),
Location::XMM(XMM::XMM0),
);
a.emit_mov(
Size::S64,
Location::GPR(GPR::RCX),
Location::XMM(XMM::XMM1),
);
a.emit_sub(Size::S64, Location::Imm32(8), Location::GPR(GPR::RSP));
a.emit_mov(Size::S64, Location::GPR(GPR::RSP), Location::GPR(GPR::RCX));
a.emit_mov(Size::S64, *param, Location::GPR(GPR::RAX));
a.emit_mov(
Size::S64,
Location::GPR(GPR::RAX),
Location::Memory(GPR::RCX, 0),
);
a.emit_mov(
Size::S64,
Location::XMM(XMM::XMM0),
Location::GPR(GPR::RAX),
);
Location::Imm64(_) => {
// Dummy value slot to be filled with `mov`.
a.emit_push(Size::S64, Location::GPR(GPR::RAX));

// Use R10 as the temporary register here, since it is callee-saved and not
// used by the callback `cb`.
a.emit_mov(Size::S64, *param, Location::GPR(GPR::R10));
a.emit_mov(
Size::S64,
Location::XMM(XMM::XMM1),
Location::GPR(GPR::RCX),
Location::GPR(GPR::R10),
Location::Memory(GPR::RSP, 0),
);
}
Location::XMM(_) => {
// Dummy value slot to be filled with `mov`.
a.emit_push(Size::S64, Location::GPR(GPR::RAX));

// XMM registers can be directly stored to memory.
a.emit_mov(Size::S64, *param, Location::Memory(GPR::RSP, 0));
}
_ => a.emit_push(Size::S64, *param),
}
}
Expand Down Expand Up @@ -1873,12 +1866,10 @@ impl X64FunctionCode {

// Restore XMMs.
if used_xmms.len() > 0 {
// FIXME: Possible dynasm bug. This is a workaround.
a.emit_mov(Size::S64, Location::GPR(GPR::RSP), Location::GPR(GPR::RDX));
for (i, r) in used_xmms.iter().enumerate() {
a.emit_mov(
Size::S64,
Location::Memory(GPR::RDX, (i * 8) as i32),
Location::Memory(GPR::RSP, (i * 8) as i32),
Location::XMM(*r),
);
}
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1 change: 0 additions & 1 deletion lib/singlepass-backend/src/lib.rs
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Expand Up @@ -40,7 +40,6 @@ extern crate smallvec;
mod codegen_x64;
mod emitter_x64;
mod machine;
pub mod protect_unix;
#[cfg(target_arch = "aarch64")]
mod translator_aarch64;

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49 changes: 0 additions & 49 deletions lib/singlepass-backend/src/protect_unix.rs
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