static List <Reg> get_push_list(CilNode.IRNode n, Code c,
metadata.MethodSpec call_ms, out metadata.TypeSpec rt,
ref Reg dest, out int rct, bool want_return = true)
{
/* Determine which registers we need to save */
var caller_preserves = c.t.cc_caller_preserves_map[call_ms.CallingConvention];
ulong defined = 0;
foreach (var si in n.stack_after)
{
defined |= si.reg.mask;
}
foreach (var si in n.stack_before)
{
defined |= si.reg.mask;
}
var rt_idx = call_ms.m.GetMethodDefSigRetTypeIndex(call_ms.msig);
rt = call_ms.m.GetTypeSpec(ref rt_idx, call_ms.gtparams, call_ms.gmparams);
rct = ir.Opcode.ct_unknown;
if (rt != null && want_return)
{
defined &= ~n.stack_after.Peek().reg.mask;
if (dest == null)
{
dest = n.stack_after.Peek().reg;
}
rct = ir.Opcode.GetCTFromType(rt);
}
var to_push = new util.Set();
to_push.Union(defined);
to_push.Intersect(caller_preserves);
List <Reg> push_list = new List <Reg>();
while (!to_push.Empty)
{
var first_set = to_push.get_first_set();
push_list.Add(c.t.regs[first_set]);
to_push.unset(first_set);
}
return(push_list);
}
protected internal override Code AssembleBoxRetTypeMethod(MethodSpec ms, TysilaState s)
{
// Move all parameters up one - this will require knowledge of the param locs
// if the return type is an object (to get the 'from' locations) and
// knowledge of the param locs in the target method (the 'to' locations)
// Allocate space on heap (boxed return object)
var cc = cc_map[ms.CallingConvention];
var cc_class_map = cc_classmap[ms.CallingConvention];
int stack_loc = 0;
var from_locs = GetRegLocs(new ir.Param
{
m = ms.m,
ms = ms,
}, ref stack_loc, cc, cc_class_map,
ms.CallingConvention,
out var from_sizes, out var from_types,
null);
stack_loc = 0;
var to_locs = GetRegLocs(new ir.Param
{
m = ms.m,
ms = ms,
}, ref stack_loc, cc, cc_class_map,
ms.CallingConvention,
out var to_sizes, out var to_types,
ms.m.SystemIntPtr);
// Generate code
var c = new Code();
c.mc = new List <MCInst>();
c.s = s;
var n = new cil.CilNode(ms, 0);
var ir = new cil.CilNode.IRNode {
parent = n, mc = c.mc
};
ir.opcode = Opcode.oc_nop;
n.irnodes.Add(ir);
c.starts = new List <cil.CilNode>();
c.starts.Add(n);
c.ms = ms;
c.t = this;
// copy from[0:n] to to[1:n+1] in reverse order so
// we don't overwrite the previous registers
ulong defined = 0;
for (int i = from_locs.Length - 1; i >= 0; i--)
{
handle_move(to_locs[i + 1], from_locs[i], c.mc, ir, c, x86_64.x86_64_Assembler.r_rax, from_sizes[i]);
defined |= to_locs[i + 1].mask;
}
// call gcmalloc with the size of the boxed version of the return
// type
var ts = ms.ReturnType;
var tsize = GetSize(ts);
var sysobj_size = layout.Layout.GetTypeSize(c.ms.m.SystemObject, c.t);
var boxed_size = util.util.align(sysobj_size + tsize, psize);
// decide on the registers we need to save around gcmalloc
var caller_preserves = cc_caller_preserves_map[ms.CallingConvention];
var to_push = new util.Set();
to_push.Union(defined);
to_push.Intersect(caller_preserves);
List <Reg> push_list = new List <Reg>();
while (!to_push.Empty)
{
var first_set = to_push.get_first_set();
push_list.Add(c.t.regs[first_set]);
to_push.unset(first_set);
}
int push_length = 0;
foreach (var r in push_list)
{
handle_push(r, ref push_length, c.mc, ir, c);
}
c.mc.Add(inst(x86_call_rel32, new Param {
t = Opcode.vl_call_target, str = "gcmalloc"
},
new Param {
t = Opcode.vl_c32, v = boxed_size
}, ir));
for (int i = push_list.Count - 1; i >= 0; i--)
{
handle_pop(push_list[i], ref push_length, c.mc, ir, c);
}
// put vtable pointer into gcmalloc result
c.mc.Add(inst(x86_mov_rm32_lab, new ContentsReg {
basereg = r_eax, size = 4
},
new Param {
t = Opcode.vl_str, str = ts.MangleType()
}, ir));
// put rax into to[0]
handle_move(to_locs[0], r_eax, c.mc, ir, c);
// unbox to[0] (i.e. increment pointer so it points to the inner data)
c.mc.Add(inst(psize == 4 ? x86_add_rm32_imm8 : x86_add_rm64_imm8, to_locs[0], sysobj_size, ir));
// call the actual function (see AssembleBoxedMethod below)
var unboxed = ms.Unbox;
var act_meth = unboxed.MangleMethod();
s.r.MethodRequestor.Request(unboxed);
// Save rax around the call and return it
// We do this because the actual method returns the address of a value type in rax
// and we want to return the address of the boxed object instead
c.mc.Add(inst(x86_push_r32, r_eax, ir));
c.mc.Add(inst(x86_call_rel32, new Param {
t = Opcode.vl_str, str = act_meth
}, ir));
c.mc.Add(inst(x86_pop_r32, r_eax, ir));
c.mc.Add(inst(x86_ret, ir));
return(c);
}