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Lose the by_ref destination style

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It's not needed.

Issue #667
This commit is contained in:
Marijn Haverbeke 2011-10-05 10:41:30 +02:00
parent babd1ff3c7
commit 975ac55b3d
1 changed files with 25 additions and 33 deletions
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58
src/comp/middle/trans.rs
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@ -2481,7 +2481,6 @@ fn join_branches(parent_cx: @block_ctxt, ins: [result]) -> @block_ctxt {
tag dest {
by_val(@mutable ValueRef);
by_ref(@mutable ValueRef);
save_in(ValueRef);
ignore;
}
@ -2493,7 +2492,6 @@ fn empty_dest_cell() -> @mutable ValueRef {
fn dup_for_join(dest: dest) -> dest {
alt dest {
by_val(_) { by_val(empty_dest_cell()) }
by_ref(_) { by_ref(empty_dest_cell()) }
_ { dest }
}
}
@ -2507,7 +2505,7 @@ fn join_returns(parent_cx: @block_ctxt, in_cxs: [@block_ctxt],
Br(cx, out.llbb);
reachable = true;
alt in_ds[i] {
by_val(cell) | by_ref(cell) {
by_val(cell) {
if option::is_none(phi) {
phi = some(EmptyPhi(out, val_ty(*cell)));
}
@ -2522,7 +2520,7 @@ fn join_returns(parent_cx: @block_ctxt, in_cxs: [@block_ctxt],
Unreachable(out);
} else {
alt out_dest {
by_val(cell) | by_ref(cell) { *cell = option::get(phi); }
by_val(cell) { *cell = option::get(phi); }
_ {}
}
}
@ -3333,7 +3331,7 @@ fn trans_lval(cx: @block_ctxt, e: @ast::expr) -> lval_result {
// A by-ref returning function
if expr_is_lval(bcx_tcx(cx), e) {
let cell = empty_dest_cell();
let bcx = trans_call(cx, f, none, args, e.id, by_ref(cell));
let bcx = trans_call(cx, f, none, args, e.id, by_val(cell));
ret lval_mem(bcx, *cell);
} else { // By-value return
let {bcx, val} = dps_to_result(cx, {|bcx, dest|
@ -3799,7 +3797,8 @@ fn trans_args(cx: @block_ctxt, outer_cx: @block_ctxt, llenv: ValueRef,
args: [ValueRef],
retslot: ValueRef,
to_zero: [{v: ValueRef, t: ty::t}],
to_revoke: [{v: ValueRef, t: ty::t}]} {
to_revoke: [{v: ValueRef, t: ty::t}],
ret_ref: bool} {
let args: [ty::arg] = ty::ty_fn_args(bcx_tcx(cx), fn_ty);
let llargs: [ValueRef] = [];
@ -3825,19 +3824,20 @@ fn trans_args(cx: @block_ctxt, outer_cx: @block_ctxt, llenv: ValueRef,
}
// Arg 0: Output pointer.
let llretty = type_of_or_i8(bcx, full_retty);
let dest_ref = false;
let llretslot = alt dest {
ignore. {
if ty::type_is_nil(tcx, full_retty) || !option::is_none(lliterbody) {
llvm::LLVMGetUndef(T_ptr(llretty))
} else { alloca(cx, llretty) }
}
save_in(dst) { dst }
by_val(_) { alloca(cx, llretty) }
by_ref(_) { dest_ref = true; alloca(cx, T_ptr(llretty)) }
let llretslot = if ret_ref {
alloca(cx, T_ptr(llretty))
} else {
alt dest {
ignore. {
if ty::type_is_nil(tcx, full_retty) ||
!option::is_none(lliterbody) {
llvm::LLVMGetUndef(T_ptr(llretty))
} else { alloca(cx, llretty) }
}
save_in(dst) { dst }
by_val(_) { alloca(cx, llretty) }
}
};
// FIXME[DSP] does this always hold?
assert dest_ref == ret_ref;
if ty::type_contains_params(tcx, retty) {
// It's possible that the callee has some generic-ness somewhere in
@ -3898,7 +3898,8 @@ fn trans_args(cx: @block_ctxt, outer_cx: @block_ctxt, llenv: ValueRef,
args: llargs,
retslot: llretslot,
to_zero: to_zero,
to_revoke: to_revoke};
to_revoke: to_revoke,
ret_ref: ret_ref};
}
fn trans_call(in_cx: @block_ctxt, f: @ast::expr,
@ -3953,12 +3954,13 @@ fn trans_call(in_cx: @block_ctxt, f: @ast::expr,
args_res.to_revoke);
alt dest {
ignore. {
if llvm::LLVMIsUndef(llretslot) != lib::llvm::True {
if llvm::LLVMIsUndef(llretslot) != lib::llvm::True &&
!args_res.ret_ref {
bcx = drop_ty(bcx, llretslot, ret_ty);
}
}
save_in(_) { } // Already saved by callee
by_ref(cell) | by_val(cell) {
by_val(cell) {
*cell = Load(bcx, llretslot);
}
}
@ -4278,13 +4280,6 @@ fn trans_temp_expr(bcx: @block_ctxt, e: @ast::expr) -> lval_result {
}
}
// FIXME[DPS] supersede by trans_temp_expr, get rid of by_ref dests
fn trans_expr_by_ref(bcx: @block_ctxt, e: @ast::expr) -> result {
let cell = empty_dest_cell();
bcx = trans_expr_dps(bcx, e, by_ref(cell));
ret rslt(bcx, *cell);
}
// Invariants:
// - things returning nil get dest=ignore
// - any lvalue expr may be given dest=by_ref
@ -4476,10 +4471,6 @@ fn lval_to_dps(bcx: @block_ctxt, e: @ast::expr, dest: dest) -> @block_ctxt {
*cell = Load(bcx, val);
}
}
by_ref(cell) {
assert is_mem;
*cell = val;
}
save_in(loc) { bcx = move_val_if_temp(bcx, INIT, loc, lv, ty); }
ignore. {}
}
@ -4728,7 +4719,8 @@ fn trans_ret(bcx: @block_ctxt, e: option::t<@ast::expr>) -> @block_ctxt {
alt e {
some(x) {
if ast_util::ret_by_ref(bcx.fcx.ret_style) {
let {bcx: cx, val} = trans_expr_by_ref(bcx, x);
let {bcx: cx, val, is_mem} = trans_lval(bcx, x);
assert is_mem;
Store(cx, val, bcx.fcx.llretptr);
bcx = cx;
} else {