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Allow use of pinned heap registers #512

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Allow use of pinned heap registers #512

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29 changes: 23 additions & 6 deletions benchmarks/lucet-benchmarks/src/context.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,8 @@ fn context_init(c: &mut Criterion) {

c.bench_function("context_init", move |b| {
b.iter(|| {
ContextHandle::create_and_init(&mut *stack, f as usize, &[]).unwrap();
ContextHandle::create_and_init(&mut *stack, f as usize, &[], std::ptr::null_mut())
.unwrap();
})
});
}
Expand All @@ -22,7 +23,13 @@ fn context_swap_return(c: &mut Criterion) {
b.iter_batched(
|| {
let mut stack = vec![0u64; 1024].into_boxed_slice();
let child = ContextHandle::create_and_init(&mut *stack, f as usize, &[]).unwrap();
let child = ContextHandle::create_and_init(
&mut *stack,
f as usize,
&[],
std::ptr::null_mut(),
)
.unwrap();
(stack, child)
},
|(stack, mut child)| unsafe {
Expand All @@ -44,8 +51,13 @@ fn context_init_swap_return(c: &mut Criterion) {
|| vec![0u64; 1024].into_boxed_slice(),
|mut stack| {
let mut parent = ContextHandle::new();
let mut child =
ContextHandle::create_and_init(&mut *stack, f as usize, &[]).unwrap();
let mut child = ContextHandle::create_and_init(
&mut *stack,
f as usize,
&[],
std::ptr::null_mut(),
)
.unwrap();
unsafe { Context::swap(&mut parent, &mut child) };
stack
},
Expand Down Expand Up @@ -332,8 +344,13 @@ fn context_init_swap_return_many_args(c: &mut Criterion) {
|| vec![0u64; 1024].into_boxed_slice(),
|mut stack| {
let mut parent = ContextHandle::new();
let mut child =
ContextHandle::create_and_init(&mut *stack, f as usize, &args).unwrap();
let mut child = ContextHandle::create_and_init(
&mut *stack,
f as usize,
&args,
std::ptr::null_mut(),
)
.unwrap();
unsafe { Context::swap(&mut parent, &mut child) };
stack
},
Expand Down
4 changes: 4 additions & 0 deletions lucet-module/src/module_data.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -59,6 +59,8 @@ pub struct ModuleFeatures {
pub lzcnt: bool,
pub popcnt: bool,
pub instruction_count: bool,
pub pinned_heap: bool,
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How's it sound to make this an Option<HeapPinStyle>? Then None means "no pinning", and HeapPinStyle can be written like

#[repr(u8)]
enum HeapPinStyle {
    PinR15 = 1
}

that we can extend if need be in the future?

I mostly want to avoid a cranelift RegUnit, even in u16 form in lucet-module - the stability of those numbers isn't guaranteed, so we could misinterpret an old module, or an old runtime could misinterpret a new module.

pub pinned_heap_register: u16,
_hidden: (),
}

Expand All @@ -75,6 +77,8 @@ impl ModuleFeatures {
lzcnt: false,
popcnt: false,
instruction_count: false,
pinned_heap: false,
pinned_heap_register: 0,
_hidden: (),
}
}
Expand Down
2 changes: 2 additions & 0 deletions lucet-runtime/lucet-runtime-internals/src/alloc/tests.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -656,6 +656,7 @@ macro_rules! alloc_tests {
inst.alloc_mut().stack_u64_mut(),
heap_touching_child as usize,
&[Val::CPtr(heap_ptr)],
heap_ptr,
)
.expect("context init succeeds");
Context::swap(&mut parent, &mut child);
Expand Down Expand Up @@ -705,6 +706,7 @@ macro_rules! alloc_tests {
inst.alloc_mut().stack_u64_mut(),
stack_pattern_child as usize,
&[Val::CPtr(heap_ptr)],
heap_ptr,
)
.expect("context init succeeds");
Context::swap(&mut parent, &mut child);
Expand Down
13 changes: 12 additions & 1 deletion lucet-runtime/lucet-runtime-internals/src/context/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -208,9 +208,10 @@ impl ContextHandle {
stack: &mut [u64],
fptr: usize,
args: &[Val],
heap: *mut core::ffi::c_void,
) -> Result<ContextHandle, Error> {
let mut child = ContextHandle::new();
Context::init(stack, &mut child, fptr, args)?;
Context::init(stack, &mut child, fptr, args, heap)?;
Ok(child)
}
}
Expand Down Expand Up @@ -303,6 +304,7 @@ impl Context {
/// &mut child,
/// entrypoint as usize,
/// &[Val::U64(120), Val::F32(3.14)],
/// std::ptr::null_mut(),
/// );
/// assert!(res.is_ok());
/// ```
Expand All @@ -326,6 +328,7 @@ impl Context {
/// &mut child,
/// entrypoint as usize,
/// &[Val::U64(120), Val::F32(3.14)],
/// std::ptr::null_mut(),
/// );
/// assert!(res.is_ok());
/// ```
Expand Down Expand Up @@ -367,6 +370,7 @@ impl Context {
child: &mut Context,
fptr: usize,
args: &[Val],
heap: *mut core::ffi::c_void,
) -> Result<(), Error> {
Context::init_with_callback(
stack,
Expand All @@ -375,6 +379,7 @@ impl Context {
ptr::null_mut(),
fptr,
args,
heap,
)
}

Expand All @@ -393,6 +398,7 @@ impl Context {
callback_data: *mut Instance,
fptr: usize,
args: &[Val],
heap: *mut core::ffi::c_void,
) -> Result<(), Error> {
if !stack_is_aligned(stack) {
return Err(Error::UnalignedStack);
Expand Down Expand Up @@ -475,6 +481,10 @@ impl Context {
// even at the entrypoint of the guest.
child.gpr.rbp = child as *const Context as u64;

// Heap pinning: r15 is not used to pass any parameters on Windows/POSIX abis, we simply set this to be the value of the heap always.
// This value will be used only when the lucet module loaded is compiled requiring use of the pinned heap register.
child.gpr.r15 = heap as u64;

Ok(())
}

Expand Down Expand Up @@ -547,6 +557,7 @@ impl Context {
/// &mut child,
/// entrypoint as usize,
/// &[],
/// std::ptr::null_mut(),
/// ).unwrap();
///
/// unsafe { Context::swap(&mut parent, &mut child); }
Expand Down
1 change: 1 addition & 0 deletions lucet-runtime/lucet-runtime-internals/src/context/tests/c_child.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -55,6 +55,7 @@ macro_rules! init_and_swap {
&mut *$stack,
$fn as usize,
&[$( $args ),*],
std::ptr::null_mut(),
).unwrap()));

child_regs = child;
Expand Down
7 changes: 6 additions & 1 deletion lucet-runtime/lucet-runtime-internals/src/context/tests/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -31,7 +31,12 @@ fn init_rejects_unaligned() {
let mut stack_unaligned = unsafe { slice::from_raw_parts_mut(ptr, len) };

// now we have the unaligned stack, let's make sure it blows up right
let res = ContextHandle::create_and_init(&mut stack_unaligned, dummy as usize, &[]);
let res = ContextHandle::create_and_init(
&mut stack_unaligned,
dummy as usize,
&[],
std::ptr::null_mut(),
);

if let Err(Error::UnalignedStack) = res {
assert!(true);
Expand Down
1 change: 1 addition & 0 deletions lucet-runtime/lucet-runtime-internals/src/context/tests/rust_child.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -51,6 +51,7 @@ macro_rules! init_and_swap {
&mut *$stack,
$fn as usize,
&[$( $args ),*],
std::ptr::null_mut(),
).unwrap();
CHILD = Some(child);

Expand Down
4 changes: 3 additions & 1 deletion lucet-runtime/lucet-runtime-internals/src/instance.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -973,7 +973,8 @@ impl Instance {

self.entrypoint = Some(func);

let mut args_with_vmctx = vec![Val::from(self.alloc.slot().heap)];
let heap = self.alloc.slot().heap;
let mut args_with_vmctx = vec![Val::from(heap)];
args_with_vmctx.extend_from_slice(args);

let self_ptr = self as *mut _;
Expand All @@ -984,6 +985,7 @@ impl Instance {
self_ptr,
func.ptr.as_usize(),
&args_with_vmctx,
heap,
)?;

self.install_activator();
Expand Down
3 changes: 2 additions & 1 deletion lucetc/lucetc/main.rs
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Expand Up @@ -100,7 +100,8 @@ pub fn run(opts: &Options) -> Result<(), Error> {
.with_bindings(bindings)
.with_opt_level(opts.opt_level)
.with_cpu_features(opts.cpu_features.clone())
.with_target(opts.target.clone());
.with_target(opts.target.clone())
.with_pinned_heap(opts.pinned_heap);

if let Some(validator) = validator.take() {
c.validator(validator);
Expand Down
9 changes: 9 additions & 0 deletions lucetc/lucetc/options.rs
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Expand Up @@ -120,6 +120,7 @@ pub struct Options {
pub pk_path: Option<PathBuf>,
pub sk_path: Option<PathBuf>,
pub count_instructions: bool,
pub pinned_heap: bool,
pub error_style: ErrorStyle,
pub target: Triple,
}
Expand Down Expand Up @@ -211,6 +212,7 @@ impl Options {
let sk_path = m.value_of("sk_path").map(PathBuf::from);
let pk_path = m.value_of("pk_path").map(PathBuf::from);
let count_instructions = m.is_present("count_instructions");
let pinned_heap = m.is_present("pinned_heap");

let error_style = match m.value_of("error_style") {
None => ErrorStyle::default(),
Expand Down Expand Up @@ -239,6 +241,7 @@ impl Options {
sk_path,
pk_path,
count_instructions,
pinned_heap,
error_style,
target,
})
Expand Down Expand Up @@ -452,6 +455,12 @@ SSE3 but not AVX:
.takes_value(false)
.help("Instrument the produced binary to count the number of wasm operations the translated program executes")
)
.arg(
Arg::with_name("pinned_heap")
.long("--pinned-heap-reg")
.takes_value(false)
.help("This feature is not stable - it may be removed in the future! Pin a register to use as this module's heap base. Typically improves performance.")
)
.arg(
Arg::with_name("error_style")
.long("error-style")
Expand Down
36 changes: 35 additions & 1 deletion lucetc/src/compiler.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,7 @@ use crate::traps::{translate_trapcode, trap_sym_for_func};
use byteorder::{LittleEndian, WriteBytesExt};
use cranelift_codegen::{
binemit, ir,
isa::RegUnit,
isa::TargetIsa,
settings::{self, Configurable},
Context as ClifContext,
Expand Down Expand Up @@ -63,6 +64,7 @@ pub struct CompilerBuilder {
heap_settings: HeapSettings,
count_instructions: bool,
canonicalize_nans: bool,
pinned_heap: bool,
validator: Option<Validator>,
}

Expand All @@ -75,6 +77,7 @@ impl CompilerBuilder {
heap_settings: HeapSettings::default(),
count_instructions: false,
canonicalize_nans: false,
pinned_heap: false,
validator: None,
}
}
Expand Down Expand Up @@ -145,6 +148,15 @@ impl CompilerBuilder {
self
}

pub fn pinned_heap(&mut self, pinned_heap: bool) {
self.pinned_heap = pinned_heap;
}

pub fn with_pinned_heap(mut self, pinned_heap: bool) -> Self {
self.pinned_heap(pinned_heap);
self
}

pub fn validator(&mut self, validator: Option<Validator>) {
self.validator = validator;
}
Expand All @@ -169,6 +181,7 @@ impl CompilerBuilder {
self.count_instructions,
&self.validator,
self.canonicalize_nans,
self.pinned_heap,
)
}
}
Expand All @@ -182,6 +195,8 @@ pub struct Compiler<'a> {
count_instructions: bool,
module_translation_state: ModuleTranslationState,
canonicalize_nans: bool,
pinned_heap: bool,
pinned_heap_register: RegUnit,
}

impl<'a> Compiler<'a> {
Expand All @@ -195,8 +210,15 @@ impl<'a> Compiler<'a> {
count_instructions: bool,
validator: &Option<Validator>,
canonicalize_nans: bool,
pinned_heap: bool,
) -> Result<Self, Error> {
let isa = Self::target_isa(target.clone(), opt_level, &cpu_features, canonicalize_nans)?;
let isa = Self::target_isa(
target.clone(),
opt_level,
&cpu_features,
canonicalize_nans,
pinned_heap,
)?;

let frontend_config = isa.frontend_config();
let mut module_info = ModuleInfo::new(frontend_config.clone());
Expand Down Expand Up @@ -228,6 +250,8 @@ impl<'a> Compiler<'a> {
_ => (cranelift_module::default_libcall_names())(libcall),
});

let pinned_heap_register = isa.register_info().parse_regunit("r15").unwrap();

let mut builder = ObjectBuilder::new(isa, "lucet_guest".to_owned(), libcalls);
builder.function_alignment(16);
let mut clif_module: ClifModule<ObjectBackend> = ClifModule::new(builder);
Expand All @@ -250,6 +274,8 @@ impl<'a> Compiler<'a> {
module_translation_state,
target,
canonicalize_nans,
pinned_heap,
pinned_heap_register,
})
}

Expand All @@ -260,6 +286,8 @@ impl<'a> Compiler<'a> {
pub fn module_features(&self) -> ModuleFeatures {
let mut mf: ModuleFeatures = (&self.cpu_features).into();
mf.instruction_count = self.count_instructions;
mf.pinned_heap = self.pinned_heap;
mf.pinned_heap_register = self.pinned_heap_register;
mf
}

Expand Down Expand Up @@ -475,6 +503,7 @@ impl<'a> Compiler<'a> {
self.opt_level,
&self.cpu_features,
self.canonicalize_nans,
self.pinned_heap,
)?,
))
}
Expand All @@ -484,6 +513,7 @@ impl<'a> Compiler<'a> {
opt_level: OptLevel,
cpu_features: &CpuFeatures,
canonicalize_nans: bool,
pinned_heap: bool,
) -> Result<Box<dyn TargetIsa>, Error> {
let mut flags_builder = settings::builder();
let isa_builder = cpu_features.isa_builder(target)?;
Expand All @@ -493,6 +523,10 @@ impl<'a> Compiler<'a> {
if canonicalize_nans {
flags_builder.enable("enable_nan_canonicalization").unwrap();
}
if pinned_heap {
flags_builder.enable("enable_pinned_reg").unwrap();
flags_builder.enable("use_pinned_reg_as_heap_base").unwrap();
}
Ok(isa_builder.finish(settings::Flags::new(flags_builder)))
}
}
Expand Down
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