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Refactor calling convention settings. (#304)

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Add a calling-convention setting to the `Flags` used as part of the
`TargetIsa`. This allows Cretonne code that generates calls to use the
correct convention, such as when emitting libcalls during legalization
or when the wasm frontend is decoding functions. This setting can be
overridden per-function.

This also adds "fast", "cold", and "fastcall" conventions, with "fast"
as the new default. Note that "fast" and "cold" are not intended to be
ABI-compatible across Cretonne versions.

This will also ensure Windows users will get an `unimplemented!` rather
than silent calling-convention mismatches, which reflects the fact that
Windows calling conventions are not yet implemented.

This also renames SpiderWASM, which isn't camel-case, to Baldrdash,
which is, and which is also a more relevant name.
This commit is contained in:
Dan Gohman
2018-04-22 21:35:18 -07:00
committed by GitHub
parent 8a9e4b9cff
commit c5b15c2396
38 changed files with 226 additions and 161 deletions
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17
lib/codegen/src/legalizer/libcall.rs
View File

@@ -3,9 +3,10 @@
use ir;
use ir::InstBuilder;
use std::vec::Vec;
use isa::TargetIsa;
/// Try to expand `inst` as a library call, returning true is successful.
pub fn expand_as_libcall(inst: ir::Inst, func: &mut ir::Function) -> bool {
pub fn expand_as_libcall(inst: ir::Inst, func: &mut ir::Function, isa: &TargetIsa) -> bool {
// Does the opcode/ctrl_type combo even have a well-known runtime library name.
let libcall =
match ir::LibCall::for_inst(func.dfg[inst].opcode(), func.dfg.ctrl_typevar(inst)) {
@@ -13,7 +14,8 @@ pub fn expand_as_libcall(inst: ir::Inst, func: &mut ir::Function) -> bool {
None => return false,
};
let funcref = find_funcref(libcall, func).unwrap_or_else(|| make_funcref(libcall, inst, func));
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();
@@ -44,9 +46,14 @@ fn find_funcref(libcall: ir::LibCall, func: &ir::Function) -> Option<ir::FuncRef
}
/// Create a funcref for `libcall` with a signature matching `inst`.
fn make_funcref(libcall: ir::LibCall, inst: ir::Inst, func: &mut ir::Function) -> ir::FuncRef {
// Start with a system_v calling convention. We'll give the ISA a chance to change it.
let mut sig = ir::Signature::new(ir::CallConv::SystemV);
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)));
}

2
lib/codegen/src/legalizer/mod.rs
View File

@@ -91,7 +91,7 @@ pub fn legalize_function(func: &mut ir::Function, cfg: &mut ControlFlowGraph, is
// We don't have any pattern expansion for this instruction either.
// Try converting it to a library call as a last resort.
if expand_as_libcall(inst, pos.func) {
if expand_as_libcall(inst, pos.func, isa) {
pos.set_position(prev_pos);
continue;
}