diff options
| -rw-r--r-- | lib/compiler/src/beam_utils.erl | 43 |
1 files changed, 37 insertions, 6 deletions
diff --git a/lib/compiler/src/beam_utils.erl b/lib/compiler/src/beam_utils.erl index 60221578bd..ebb885815f 100644 --- a/lib/compiler/src/beam_utils.erl +++ b/lib/compiler/src/beam_utils.erl @@ -118,6 +118,7 @@ is_killed(R, Is, D) -> St = #live{lbl=D,res=gb_trees:empty()}, case check_liveness(R, Is, St) of {killed,_} -> true; + {exit_not_used,_} -> true; {_,_} -> false end. @@ -130,6 +131,7 @@ is_killed_at(R, Lbl, D) when is_integer(Lbl) -> St0 = #live{lbl=D,res=gb_trees:empty()}, case check_liveness_at(R, Lbl, St0) of {killed,_} -> true; + {exit_not_used,_} -> true; {_,_} -> false end. @@ -146,6 +148,7 @@ is_not_used(R, Is, D) -> St = #live{lbl=D,res=gb_trees:empty()}, case check_liveness(R, Is, St) of {used,_} -> false; + {exit_not_used,_} -> false; {_,_} -> true end. @@ -347,6 +350,9 @@ split_even(Rs) -> split_even(Rs, [], []). %% %% killed - Reg is assigned or killed by an allocation instruction. %% not_used - the value of Reg is not used, but Reg must not be garbage +%% exit_not_used - the value of Reg is not used, but must not be garbage +%% because the stack will be scanned because an +%% exit BIF will raise an exception %% used - Reg is used check_liveness(R, [{block,Blk}|Is], St0) -> @@ -370,6 +376,8 @@ check_liveness(R, [{test,_,{f,Fail},As}|Is], St0) -> case check_liveness_at(R, Fail, St0) of {killed,St1} -> check_liveness(R, Is, St1); + {exit_not_used,St1} -> + check_liveness(R, Is, St1); {not_used,St1} -> not_used(check_liveness(R, Is, St1)); {used,_}=Used -> @@ -432,7 +440,7 @@ check_liveness(R, [{bs_init,_,_,Live,Ss,Dst}|Is], St) -> false -> if R =:= Dst -> {killed,St}; - true -> check_liveness(R, Is, St) + true -> not_used(check_liveness(R, Is, St)) end end end; @@ -466,7 +474,7 @@ check_liveness(R, [{call_ext,Live,_}=I|Is], St) -> %% We must make sure we don't check beyond this %% instruction or we will fall through into random %% unrelated code and get stuck in a loop. - {killed,St} + {exit_not_used,St} end end; check_liveness(R, [{call_fun,Live}|Is], St) -> @@ -631,6 +639,7 @@ check_liveness_at(R, Lbl, #live{lbl=Ll,res=ResMemorized}=St0) -> {Res,St#live{res=gb_trees:insert(Lbl, Res, St#live.res)}} end. +not_used({exit_not_used,St}) -> {not_used,St}; not_used({killed,St}) -> {not_used,St}; not_used({_,_}=Res) -> Res. @@ -659,13 +668,30 @@ check_liveness_block({x,X}=R, [{set,Ds,Ss,{alloc,Live,Op}}|Is], St0) -> {killed,St0}; true -> case check_liveness_block_1(R, Ss, Ds, Op, Is, St0) of - {killed,St} -> {not_used,St}; {transparent,St} -> {alloc_used,St}; - {_,_}=Res -> Res + {_,_}=Res -> not_used(Res) end end; -check_liveness_block({y,_}=R, [{set,Ds,Ss,{alloc,_Live,Op}}|Is], St) -> - check_liveness_block_1(R, Ss, Ds, Op, Is, St); +check_liveness_block({y,_}=R, [{set,Ds,Ss,{alloc,_Live,Op}}|Is], St0) -> + case check_liveness_block_1(R, Ss, Ds, Op, Is, St0) of + {transparent,St} -> {alloc_used,St}; + {_,_}=Res -> not_used(Res) + end; +check_liveness_block({y,_}=R, [{set,Ds,Ss,{try_catch,_,Op}}|Is], St0) -> + case Ds of + [R] -> + {killed,St0}; + _ -> + case check_liveness_block_1(R, Ss, Ds, Op, Is, St0) of + {exit_not_used,St} -> + {used,St}; + {transparent,St} -> + %% Conservatively assumed that it is used. + {used,St}; + {_,_}=Res -> + Res + end + end; check_liveness_block(R, [{set,Ds,Ss,Op}|Is], St) -> check_liveness_block_1(R, Ss, Ds, Op, Is, St); check_liveness_block(_, [], St) -> {transparent,St}. @@ -681,6 +707,11 @@ check_liveness_block_1(R, Ss, Ds, Op, Is, St0) -> true -> {killed,St}; false -> check_liveness_block(R, Is, St) end; + {exit_not_used,St} -> + case member(R, Ds) of + true -> {exit_not_used,St}; + false -> check_liveness_block(R, Is, St) + end; {not_used,St} -> not_used(case member(R, Ds) of true -> {killed,St}; |