diff options
Diffstat (limited to 'lib/compiler/src/beam_block.erl')
| -rw-r--r-- | lib/compiler/src/beam_block.erl | 58 |
1 files changed, 38 insertions, 20 deletions
diff --git a/lib/compiler/src/beam_block.erl b/lib/compiler/src/beam_block.erl index d0536e0669..47a2be8ab5 100644 --- a/lib/compiler/src/beam_block.erl +++ b/lib/compiler/src/beam_block.erl @@ -36,13 +36,11 @@ module({Mod,Exp,Attr,Fs0,Lc}, Opts) -> function({function,Name,Arity,CLabel,Is0}, Blockify) -> try %% Collect basic blocks and optimize them. - Is2 = case Blockify of - true -> - Is1 = blockify(Is0), - embed_lines(Is1); - false -> - Is0 + Is1 = case Blockify of + false -> Is0; + true -> blockify(Is0) end, + Is2 = embed_lines(Is1), Is3 = local_cse(Is2), Is4 = beam_utils:anno_defs(Is3), Is5 = move_allocates(Is4), @@ -110,7 +108,8 @@ collect({put_tuple,A,D}) -> {set,[D],[],{put_tuple,A}}; collect({put,S}) -> {set,[],[S],put}; collect({get_tuple_element,S,I,D}) -> {set,[D],[S],{get_tuple_element,I}}; collect({set_tuple_element,S,D,I}) -> {set,[],[S,D],{set_tuple_element,I}}; -collect({get_list,S,D1,D2}) -> {set,[D1,D2],[S],get_list}; +collect({get_hd,S,D}) -> {set,[D],[S],get_hd}; +collect({get_tl,S,D}) -> {set,[D],[S],get_tl}; collect(remove_message) -> {set,[],[],remove_message}; collect({put_map,F,Op,S,D,R,{list,Puts}}) -> {set,[D],[S|Puts],{alloc,R,{put_map,Op,F}}}; @@ -138,6 +137,11 @@ embed_lines([{block,B2},{line,_}=Line,{block,B1}|T], Acc) -> embed_lines([{block,B1},{line,_}=Line|T], Acc) -> B = {block,[{set,[],[],Line}|B1]}, embed_lines([B|T], Acc); +embed_lines([{block,B2},{block,B1}|T], Acc) -> + %% This can only happen when beam_block is run for + %% the second time. + B = {block,B1++B2}, + embed_lines([B|T], Acc); embed_lines([I|Is], Acc) -> embed_lines(Is, [I|Acc]); embed_lines([], Acc) -> Acc. @@ -205,7 +209,7 @@ move_allocates([]) -> []. move_allocates_1([{'%anno',_}|Is], Acc) -> move_allocates_1(Is, Acc); -move_allocates_1([I|Is], [{set,[],[],{alloc,Live0,Info}}|Acc]=Acc0) -> +move_allocates_1([I|Is], [{set,[],[],{alloc,Live0,Info0}}|Acc]=Acc0) -> case alloc_may_pass(I) of false -> move_allocates_1(Is, [I|Acc0]); @@ -214,6 +218,7 @@ move_allocates_1([I|Is], [{set,[],[],{alloc,Live0,Info}}|Acc]=Acc0) -> not_possible -> move_allocates_1(Is, [I|Acc0]); Live when is_integer(Live) -> + Info = safe_info(Info0), A = {set,[],[],{alloc,Live,Info}}, move_allocates_1(Is, [A,I|Acc]) end @@ -222,12 +227,20 @@ move_allocates_1([I|Is], Acc) -> move_allocates_1(Is, [I|Acc]); move_allocates_1([], Acc) -> Acc. +alloc_may_pass({set,_,[{fr,_}],fmove}) -> false; alloc_may_pass({set,_,_,{alloc,_,_}}) -> false; alloc_may_pass({set,_,_,{set_tuple_element,_}}) -> false; alloc_may_pass({set,_,_,put_list}) -> false; alloc_may_pass({set,_,_,put}) -> false; alloc_may_pass({set,_,_,_}) -> true. +safe_info({nozero,Stack,Heap,_}) -> + %% nozero is not safe if the allocation instruction is moved + %% upwards past an instruction that may throw an exception + %% (such as element/2). + {zero,Stack,Heap,[]}; +safe_info(Info) -> Info. + %% opt([Instruction]) -> [Instruction] %% Optimize the instruction stream inside a basic block. @@ -251,6 +264,16 @@ opt([{set,[D1],[{integer,Idx1},Reg],{bif,element,{f,L}}}=I1, {set,[D2],[{integer,Idx2},Reg],{bif,element,{f,L}}}=I2|Is]) when Idx1 < Idx2, D1 =/= D2, D1 =/= Reg, D2 =/= Reg -> opt([I2,I1|Is]); +opt([{set,Hd0,Cons,get_hd}=GetHd, + {set,Tl0,Cons,get_tl}=GetTl|Is0]) -> + case {opt_moves(Hd0, [GetTl|Is0]),opt_moves(Tl0, [GetHd|Is0])} of + {{Hd0,Is},{Tl0,_}} -> + [GetHd|opt(Is)]; + {{Hd,Is},{Tl0,_}} -> + [{set,Hd,Cons,get_hd}|opt(Is)]; + {{_,_},{Tl,Is}} -> + [{set,Tl,Cons,get_tl}|opt(Is)] + end; opt([{set,Ds0,Ss,Op}|Is0]) -> {Ds,Is} = opt_moves(Ds0, Is0), [{set,Ds,Ss,Op}|opt(Is)]; @@ -266,17 +289,6 @@ opt_moves([D0]=Ds, Is0) -> case opt_move(D0, Is0) of not_possible -> {Ds,Is0}; {D1,Is} -> {[D1],Is} - end; -opt_moves([X0,Y0], Is0) -> - {X,Is2} = case opt_move(X0, Is0) of - not_possible -> {X0,Is0}; - {Y0,_} -> {X0,Is0}; - {_X1,_Is1} = XIs1 -> XIs1 - end, - case opt_move(Y0, Is2) of - not_possible -> {[X,Y0],Is2}; - {X,_} -> {[X,Y0],Is2}; - {Y,Is} -> {[X,Y],Is} end. %% opt_move(Dest, [Instruction]) -> {UpdatedDest,[Instruction]} | not_possible @@ -619,7 +631,13 @@ cse_find(Expr, Es) -> end. cse_expr({set,[D],Ss,{bif,N,_}}) -> - {ok,D,{{bif,N},Ss}}; + case D of + {fr,_} -> + %% There are too many things that can go wrong. + none; + _ -> + {ok,D,{{bif,N},Ss}} + end; cse_expr({set,[D],Ss,{alloc,_,{gc_bif,N,_}}}) -> {ok,D,{{gc_bif,N},Ss}}; cse_expr({set,[D],Ss,put_list}) -> |