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wasmtime: Implement table.get and table.set

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These instructions have fast, inline JIT paths for the common cases, and only
call out to host VM functions for the slow paths. This required some changes to
`cranelift-wasm`'s `FuncEnvironment`: instead of taking a `FuncCursor` to insert
an instruction sequence within the current basic block,
`FuncEnvironment::translate_table_{get,set}` now take a `&mut FunctionBuilder`
so that they can create whole new basic blocks. This is necessary for
implementing GC read/write barriers that involve branching (e.g. checking for
null, or whether a store buffer is at capacity).

Furthermore, it required that the `load`, `load_complex`, and `store`
instructions handle loading and storing through an `r{32,64}` rather than just
`i{32,64}` addresses. This involved making `r{32,64}` types acceptable
instantiations of the `iAddr` type variable, plus a few new instruction
encodings.

Part of #929
This commit is contained in:
Nick Fitzgerald
2020-06-23 10:43:08 -07:00
parent 959e424c81
commit 8c5f59c0cf
20 changed files with 894 additions and 76 deletions
Download Patch File Download Diff File Expand all files Collapse all files

40
cranelift/codegen/meta/src/isa/x86/encodings.rs
View File

@@ -231,6 +231,32 @@ impl PerCpuModeEncodings {
});
}
/// Add encodings for `inst.r32` to X86_32.
/// Add encodings for `inst.r32` to X86_64 with and without REX.
/// Add encodings for `inst.r64` to X86_64 with a REX.W prefix.
fn enc_r32_r64_instp(
&mut self,
inst: &Instruction,
template: Template,
instp: InstructionPredicateNode,
) {
self.enc32_func(inst.bind(R32), template.nonrex(), |builder| {
builder.inst_predicate(instp.clone())
});
// REX-less encoding must come after REX encoding so we don't use it by default. Otherwise
// reg-alloc would never use r8 and up.
self.enc64_func(inst.bind(R32), template.rex(), |builder| {
builder.inst_predicate(instp.clone())
});
self.enc64_func(inst.bind(R32), template.nonrex(), |builder| {
builder.inst_predicate(instp.clone())
});
self.enc64_func(inst.bind(R64), template.rex().w(), |builder| {
builder.inst_predicate(instp)
});
}
/// Add encodings for `inst.r32` to X86_32.
/// Add encodings for `inst.r64` to X86_64 with a REX.W prefix.
fn enc_r32_r64_rex_only(&mut self, inst: impl Into<InstSpec>, template: Template) {
@@ -810,6 +836,11 @@ fn define_memory(
recipe.opcodes(&MOV_LOAD),
is_load_complex_length_two.clone(),
);
e.enc_r32_r64_instp(
load_complex,
recipe.opcodes(&MOV_LOAD),
is_load_complex_length_two.clone(),
);
e.enc_x86_64_instp(
uload32_complex,
recipe.opcodes(&MOV_LOAD),
@@ -855,6 +886,11 @@ fn define_memory(
recipe.opcodes(&MOV_STORE),
is_store_complex_length_three.clone(),
);
e.enc_r32_r64_instp(
store_complex,
recipe.opcodes(&MOV_STORE),
is_store_complex_length_three.clone(),
);
e.enc_x86_64_instp(
istore32_complex,
recipe.opcodes(&MOV_STORE),
@@ -948,6 +984,10 @@ fn define_memory(
e.enc64_rec(fill_nop.bind(ty), rec_ffillnull, 0);
e.enc32_rec(fill_nop.bind(ty), rec_ffillnull, 0);
}
for &ty in &[R64, R32] {
e.enc64_rec(fill_nop.bind(ty), rec_fillnull, 0);
e.enc32_rec(fill_nop.bind(ty), rec_fillnull, 0);
}
// Load 32 bits from `b1`, `i8` and `i16` spill slots. See `spill.b1` above.

4
cranelift/codegen/meta/src/shared/instructions.rs
View File

@@ -211,7 +211,7 @@ fn define_control_flow(
let iAddr = &TypeVar::new(
"iAddr",
"An integer address type",
TypeSetBuilder::new().ints(32..64).build(),
TypeSetBuilder::new().ints(32..64).refs(32..64).build(),
);
{
@@ -744,7 +744,7 @@ pub(crate) fn define(
let iAddr = &TypeVar::new(
"iAddr",
"An integer address type",
TypeSetBuilder::new().ints(32..64).build(),
TypeSetBuilder::new().ints(32..64).refs(32..64).build(),
);
let Ref = &TypeVar::new(