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Generate trampolines based on signatures (#947)

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* Generate trampolines based on signatures

Instead of generating a trampoline-per-function generate a
trampoline-per-signature. This should hopefully greatly increase the
cache hit rate on trampolines within a module and avoid generating a
function-per-function.

* Update crates/runtime/src/traphandlers.rs

Co-Authored-By: Sergei Pepyakin <s.pepyakin@gmail.com>

Co-authored-by: Sergei Pepyakin <s.pepyakin@gmail.com>
This commit is contained in:
Alex Crichton
2020-02-18 12:32:52 -06:00
committed by GitHub
parent c94cdc7730
commit 16affacafb
5 changed files with 58 additions and 53 deletions
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49
crates/jit/src/compiler.rs
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@@ -22,6 +22,7 @@ use wasmtime_environ::{
};
use wasmtime_runtime::{
InstantiationError, SignatureRegistry, TrapRegistration, TrapRegistry, VMFunctionBody,
VMSharedSignatureIndex,
};
/// Select which kind of compilation to use.
@@ -51,7 +52,7 @@ pub struct Compiler {
code_memory: CodeMemory,
trap_registry: TrapRegistry,
trampoline_park: HashMap<*const VMFunctionBody, *const VMFunctionBody>,
trampoline_park: HashMap<VMSharedSignatureIndex, *const VMFunctionBody>,
signatures: SignatureRegistry,
strategy: CompilationStrategy,
cache_config: CacheConfig,
@@ -200,37 +201,31 @@ impl Compiler {
/// Create a trampoline for invoking a function.
pub(crate) fn get_trampoline(
&mut self,
callee_address: *const VMFunctionBody,
signature: &ir::Signature,
value_size: usize,
) -> Result<*const VMFunctionBody, SetupError> {
use std::collections::hash_map::Entry::{Occupied, Vacant};
Ok(match self.trampoline_park.entry(callee_address) {
Occupied(entry) => *entry.get(),
Vacant(entry) => {
let body = make_trampoline(
&*self.isa,
&mut self.code_memory,
&mut self.fn_builder_ctx,
callee_address,
signature,
value_size,
)?;
entry.insert(body);
body
}
})
let index = self.signatures.register(signature);
if let Some(trampoline) = self.trampoline_park.get(&index) {
return Ok(*trampoline);
}
let body = make_trampoline(
&*self.isa,
&mut self.code_memory,
&mut self.fn_builder_ctx,
signature,
value_size,
)?;
self.trampoline_park.insert(index, body);
return Ok(body);
}
/// Create and publish a trampoline for invoking a function.
pub fn get_published_trampoline(
&mut self,
callee_address: *const VMFunctionBody,
signature: &ir::Signature,
value_size: usize,
) -> Result<*const VMFunctionBody, SetupError> {
let result = self.get_trampoline(callee_address, signature, value_size)?;
let result = self.get_trampoline(signature, value_size)?;
self.publish_compiled_code();
Ok(result)
}
@@ -256,7 +251,6 @@ fn make_trampoline(
isa: &dyn TargetIsa,
code_memory: &mut CodeMemory,
fn_builder_ctx: &mut FunctionBuilderContext,
callee_address: *const VMFunctionBody,
signature: &ir::Signature,
value_size: usize,
) -> Result<*const VMFunctionBody, SetupError> {
@@ -272,6 +266,9 @@ fn make_trampoline(
// Add the caller `vmctx` parameter.
wrapper_sig.params.push(ir::AbiParam::new(pointer_type));
// Add the `callee_address` parameter.
wrapper_sig.params.push(ir::AbiParam::new(pointer_type));
// Add the `values_vec` parameter.
wrapper_sig.params.push(ir::AbiParam::new(pointer_type));
@@ -287,9 +284,9 @@ fn make_trampoline(
builder.switch_to_block(block0);
builder.seal_block(block0);
let (vmctx_ptr_val, caller_vmctx_ptr_val, values_vec_ptr_val) = {
let (vmctx_ptr_val, caller_vmctx_ptr_val, callee_value, values_vec_ptr_val) = {
let params = builder.func.dfg.block_params(block0);
(params[0], params[1], params[2])
(params[0], params[1], params[2], params[3])
};
// Load the argument values out of `values_vec`.
@@ -318,10 +315,6 @@ fn make_trampoline(
let new_sig = builder.import_signature(signature.clone());
// TODO: It's possible to make this a direct call. We just need Cranelift
// to support functions declared with an immediate integer address.
// ExternalName::Absolute(u64). Let's do it.
let callee_value = builder.ins().iconst(pointer_type, callee_address as i64);
let call = builder
.ins()
.call_indirect(new_sig, callee_value, &callee_args);