diff options
| -rw-r--r-- | lib/compiler/src/beam_ssa_pre_codegen.erl | 62 | ||||
| -rw-r--r-- | lib/compiler/test/beam_ssa_SUITE.erl | 26 |
2 files changed, 84 insertions, 4 deletions
diff --git a/lib/compiler/src/beam_ssa_pre_codegen.erl b/lib/compiler/src/beam_ssa_pre_codegen.erl index 9af72afca7..a2e687930b 100644 --- a/lib/compiler/src/beam_ssa_pre_codegen.erl +++ b/lib/compiler/src/beam_ssa_pre_codegen.erl @@ -156,7 +156,9 @@ passes(Opts) -> %% Allocate registers. ?PASS(linear_scan), ?PASS(frame_size), - ?PASS(turn_yregs)], + ?PASS(turn_yregs), + + ?PASS(assert_no_critical_edges)], [P || P <- Ps, P =/= ignore]. function(#b_function{anno=Anno,args=Args,bs=Blocks0,cnt=Count0}=F0, @@ -1321,10 +1323,11 @@ fix_receives_1([{L,Blk}|Ls], Blocks0, Count0) -> LoopExit = find_loop_exit(Rm, Blocks0), Defs0 = beam_ssa:def([L], Blocks0), CommonUsed = recv_common(Defs0, LoopExit, Blocks0), - {Blocks1,Count1} = recv_fix_common(CommonUsed, LoopExit, Rm, - Blocks0, Count0), + {Blocks1,Count1} = recv_crit_edges(Rm, LoopExit, Blocks0, Count0), + {Blocks2,Count2} = recv_fix_common(CommonUsed, LoopExit, Rm, + Blocks1, Count1), Defs = ordsets:subtract(Defs0, CommonUsed), - {Blocks,Count} = fix_receive(Rm, Defs, Blocks1, Count1), + {Blocks,Count} = fix_receive(Rm, Defs, Blocks2, Count2), fix_receives_1(Ls, Blocks, Count); #b_blk{} -> fix_receives_1(Ls, Blocks0, Count0) @@ -1341,6 +1344,57 @@ recv_common(Defs, Exit, Blocks) -> Def = ordsets:subtract(Defs, ExitDefs), ordsets:intersection(Def, ExitUsed). +%% recv_crit_edges([RemoveMessageLabel], LoopExit, +%% Blocks0, Count0) -> {Blocks,Count}. +%% +%% Adds dummy blocks on all conditional jumps to the exit block so that +%% recv_fix_common/5 can insert phi nodes without having to worry about +%% critical edges. + +recv_crit_edges(_Rms, none, Blocks0, Count0) -> + {Blocks0, Count0}; +recv_crit_edges(Rms, Exit, Blocks0, Count0) -> + Ls = beam_ssa:rpo(Rms, Blocks0), + rce_insert_edges(Ls, Exit, Count0, Blocks0). + +rce_insert_edges([L | Ls], Exit, Count0, Blocks0) -> + Successors = beam_ssa:successors(map_get(L, Blocks0)), + case member(Exit, Successors) of + true when Successors =/= [Exit] -> + {Blocks, Count} = rce_insert_edge(L, Exit, Count0, Blocks0), + rce_insert_edges(Ls, Exit, Count, Blocks); + _ -> + rce_insert_edges(Ls, Exit, Count0, Blocks0) + end; +rce_insert_edges([], _Exit, Count, Blocks) -> + {Blocks, Count}. + +rce_insert_edge(L, Exit, Count, Blocks0) -> + #b_blk{last=Last0} = FromBlk0 = map_get(L, Blocks0), + + ToExit = #b_br{bool=#b_literal{val=true},succ=Exit,fail=Exit}, + + FromBlk = FromBlk0#b_blk{last=rce_reroute_terminator(Last0, Exit, Count)}, + EdgeBlk = #b_blk{anno=#{},is=[],last=ToExit}, + + Blocks = Blocks0#{ Count => EdgeBlk, L => FromBlk }, + {Blocks, Count + 1}. + +rce_reroute_terminator(#b_br{succ=Exit}=Last, Exit, New) -> + rce_reroute_terminator(Last#b_br{succ=New}, Exit, New); +rce_reroute_terminator(#b_br{fail=Exit}=Last, Exit, New) -> + rce_reroute_terminator(Last#b_br{fail=New}, Exit, New); +rce_reroute_terminator(#b_br{}=Last, _Exit, _New) -> + Last; +rce_reroute_terminator(#b_switch{fail=Exit}=Last, Exit, New) -> + rce_reroute_terminator(Last#b_switch{fail=New}, Exit, New); +rce_reroute_terminator(#b_switch{list=List0}=Last, Exit, New) -> + List = [if + Lbl =:= Exit -> {Arg, New}; + Lbl =/= Exit -> {Arg, Lbl} + end || {Arg, Lbl} <- List0], + Last#b_switch{list=List}. + %% recv_fix_common([CommonVar], LoopExit, [RemoveMessageLabel], %% Blocks0, Count0) -> {Blocks,Count}. %% Handle variables alwys defined in a receive and used diff --git a/lib/compiler/test/beam_ssa_SUITE.erl b/lib/compiler/test/beam_ssa_SUITE.erl index a741ebbdf9..256bb95559 100644 --- a/lib/compiler/test/beam_ssa_SUITE.erl +++ b/lib/compiler/test/beam_ssa_SUITE.erl @@ -190,6 +190,12 @@ recv(_Config) -> self() ! {[self(),r1],{2,99,<<"data">>}}, {Parent,r1,<<1:32,2:8,99:8,"data">>} = tricky_recv_4(), + %% Test tricky_recv_5/0. + self() ! 1, + a = tricky_recv_5(), + self() ! 2, + b = tricky_recv_5(), + ok. sync_wait_mon({Pid, Ref}, Timeout) -> @@ -295,6 +301,26 @@ tricky_recv_4() -> end, id({Pid,R,Request}). +%% beam_ssa_pre_codegen would accidentally create phi nodes on critical edges +%% when fixing up receives; the call to id/2 can either succeed or land in the +%% catch block, and we added a phi node to its immediate successor. +tricky_recv_5() -> + try + receive + X=1 -> + id(42), + a; + X=2 -> + b + end, + case X of + 1 -> a; + 2 -> b + end + catch + _:_ -> c + end. + maps(_Config) -> {'EXIT',{{badmatch,#{}},_}} = (catch maps_1(any)), ok. |