T0b1/wasmtime
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Stack overflow checking with stack probes.

Browse Source 
This adds a libcall name, a calling convention, and settings for
emitting stack probes, and implements them for x86 system_v ABIs.
This commit is contained in:
Dan Gohman
2018-04-20 21:41:45 -07:00
parent c5b15c2396
commit 3b1d805758
20 changed files with 585 additions and 155 deletions
Download Patch File Download Diff File Expand all files Collapse all files

48
lib/codegen/src/legalizer/libcall.rs
View File

@@ -1,7 +1,7 @@
//! Expanding instructions as runtime library calls.
use ir;
use ir::InstBuilder;
use ir::{InstBuilder, get_libcall_funcref};
use std::vec::Vec;
use isa::TargetIsa;
@@ -14,58 +14,14 @@ pub fn expand_as_libcall(inst: ir::Inst, func: &mut ir::Function, isa: &TargetIs
None => return false,
};
let funcref =
find_funcref(libcall, func).unwrap_or_else(|| make_funcref(libcall, inst, func, isa));
// Now we convert `inst` to a call. First save the arguments.
let mut args = Vec::new();
args.extend_from_slice(func.dfg.inst_args(inst));
// The replace builder will preserve the instruction result values.
let funcref = get_libcall_funcref(libcall, func, inst, isa);
func.dfg.replace(inst).call(funcref, &args);
// TODO: ask the ISA to legalize the signature.
true
}
/// Get the existing function reference for `libcall` in `func` if it exists.
fn find_funcref(libcall: ir::LibCall, func: &ir::Function) -> Option<ir::FuncRef> {
// We're assuming that all libcall function decls are at the end.
// If we get this wrong, worst case we'll have duplicate libcall decls which is harmless.
for (fref, func_data) in func.dfg.ext_funcs.iter().rev() {
match func_data.name {
ir::ExternalName::LibCall(lc) => {
if lc == libcall {
return Some(fref);
}
}
_ => break,
}
}
None
}
/// Create a funcref for `libcall` with a signature matching `inst`.
fn make_funcref(
libcall: ir::LibCall,
inst: ir::Inst,
func: &mut ir::Function,
isa: &TargetIsa,
) -> ir::FuncRef {
// Start with a fast calling convention. We'll give the ISA a chance to change it.
let mut sig = ir::Signature::new(isa.flags().call_conv());
for &v in func.dfg.inst_args(inst) {
sig.params.push(ir::AbiParam::new(func.dfg.value_type(v)));
}
for &v in func.dfg.inst_results(inst) {
sig.returns.push(ir::AbiParam::new(func.dfg.value_type(v)));
}
let sigref = func.import_signature(sig);
// TODO: Can libcalls be colocated in some circumstances?
func.import_function(ir::ExtFuncData {
name: ir::ExternalName::LibCall(libcall),
signature: sigref,
colocated: false,
})
}