1 files changed, 54 insertions, 0 deletions
diff --git a/third_party/rust/cranelift-codegen/src/legalizer/call.rs b/third_party/rust/cranelift-codegen/src/legalizer/call.rs
new file mode 100644
index 0000000000..4321dbb90b
--- /dev/null
+++ b/third_party/rust/cranelift-codegen/src/legalizer/call.rs
@@ -0,0 +1,54 @@
+//! Legalization of calls.
+//!
+//! This module exports the `expand_call` function which transforms a `call`
+//! instruction into `func_addr` and `call_indirect` instructions.
+
+use crate::cursor::{Cursor, FuncCursor};
+use crate::flowgraph::ControlFlowGraph;
+use crate::ir::{self, InstBuilder};
+use crate::isa::TargetIsa;
+
+/// Expand a `call` instruction. This lowers it to a `call_indirect`, which
+/// is only done if the ABI doesn't support direct calls.
+pub fn expand_call(
+    inst: ir::Inst,
+    func: &mut ir::Function,
+    _cfg: &mut ControlFlowGraph,
+    isa: &dyn TargetIsa,
+) {
+    // Unpack the instruction.
+    let (func_ref, old_args) = match func.dfg[inst] {
+        ir::InstructionData::Call {
+            opcode,
+            ref args,
+            func_ref,
+        } => {
+            debug_assert_eq!(opcode, ir::Opcode::Call);
+            (func_ref, args.clone())
+        }
+        _ => panic!("Wanted call: {}", func.dfg.display_inst(inst, None)),
+    };
+
+    let ptr_ty = isa.pointer_type();
+
+    let sig = func.dfg.ext_funcs[func_ref].signature;
+
+    let callee = {
+        let mut pos = FuncCursor::new(func).at_inst(inst);
+        pos.use_srcloc(inst);
+        pos.ins().func_addr(ptr_ty, func_ref)
+    };
+
+    let mut new_args = ir::ValueList::default();
+    new_args.push(callee, &mut func.dfg.value_lists);
+    for i in 0..old_args.len(&func.dfg.value_lists) {
+        new_args.push(
+            old_args.as_slice(&func.dfg.value_lists)[i],
+            &mut func.dfg.value_lists,
+        );
+    }
+
+    func.dfg
+        .replace(inst)
+        .CallIndirect(ir::Opcode::CallIndirect, ptr_ty, sig, new_args);
+}