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authorBjörn Gustavsson <[email protected]>2013-03-14 10:11:40 +0100
committerBjörn Gustavsson <[email protected]>2013-03-19 15:08:45 +0100
commitf70f8f549bc0adca05f89e860b87dccd20a1e086 (patch)
tree2e10724fc9415656930de73a4dd0db5b1299d4c3 /lib
parente5df75bfc94662ffe9c36e0b1643cef0104586e0 (diff)
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Fix slow compilation of complex guards
beam_utils:is_not_used_at/3 could be very slow for complex guards, because the cached result for previously encountered labels were neither used nor updated within blocks. Reported-by: Magnus Müller
Diffstat (limited to 'lib')
-rw-r--r--lib/compiler/src/beam_utils.erl94
-rw-r--r--lib/compiler/test/andor_SUITE.erl33
2 files changed, 81 insertions, 46 deletions
diff --git a/lib/compiler/src/beam_utils.erl b/lib/compiler/src/beam_utils.erl
index 8af0447f63..554c14f57a 100644
--- a/lib/compiler/src/beam_utils.erl
+++ b/lib/compiler/src/beam_utils.erl
@@ -61,7 +61,7 @@ is_killed_block(R, Is) ->
%% to determine the kill state across branches.
is_killed(R, Is, D) ->
- St = #live{bl=fun check_killed_block/2,lbl=D,res=gb_trees:empty()},
+ St = #live{bl=check_killed_block_fun(),lbl=D,res=gb_trees:empty()},
case check_liveness(R, Is, St) of
{killed,_} -> true;
{used,_} -> false;
@@ -72,7 +72,7 @@ is_killed(R, Is, D) ->
%% Determine whether Reg is killed at label Lbl.
is_killed_at(R, Lbl, D) when is_integer(Lbl) ->
- St0 = #live{bl=fun check_killed_block/2,lbl=D,res=gb_trees:empty()},
+ St0 = #live{bl=check_killed_block_fun(),lbl=D,res=gb_trees:empty()},
case check_liveness_at(R, Lbl, St0) of
{killed,_} -> true;
{used,_} -> false;
@@ -87,7 +87,7 @@ is_killed_at(R, Lbl, D) when is_integer(Lbl) ->
%% across branches.
is_not_used(R, Is, D) ->
- St = #live{bl=check_used_block_fun(D),lbl=D,res=gb_trees:empty()},
+ St = #live{bl=fun check_used_block/3,lbl=D,res=gb_trees:empty()},
case check_liveness(R, Is, St) of
{killed,_} -> true;
{used,_} -> false;
@@ -102,7 +102,7 @@ is_not_used(R, Is, D) ->
%% across branches.
is_not_used_at(R, Lbl, D) ->
- St = #live{bl=check_used_block_fun(D),lbl=D,res=gb_trees:empty()},
+ St = #live{bl=fun check_used_block/3,lbl=D,res=gb_trees:empty()},
case check_liveness_at(R, Lbl, St) of
{killed,_} -> true;
{used,_} -> false;
@@ -246,10 +246,10 @@ combine_heap_needs(H1, H2) when is_integer(H1), is_integer(H2) ->
check_liveness(R, [{set,_,_,_}=I|_], St) ->
erlang:error(only_allowed_in_blocks, [R,I,St]);
-check_liveness(R, [{block,Blk}|Is], #live{bl=BlockCheck}=St) ->
- case BlockCheck(R, Blk) of
- transparent -> check_liveness(R, Is, St);
- Other when is_atom(Other) -> {Other,St}
+check_liveness(R, [{block,Blk}|Is], #live{bl=BlockCheck}=St0) ->
+ case BlockCheck(R, Blk, St0) of
+ {transparent,St} -> check_liveness(R, Is, St);
+ {Other,_}=Res when is_atom(Other) -> Res
end;
check_liveness(R, [{label,_}|Is], St) ->
check_liveness(R, Is, St);
@@ -533,6 +533,9 @@ check_liveness_fail(R, Op, Args, Fail, St) ->
%%
%% (Unknown instructions will cause an exception.)
+check_killed_block_fun() ->
+ fun(R, Is, St) -> {check_killed_block(R, Is),St} end.
+
check_killed_block({x,X}, [{set,_,_,{alloc,Live,_}}|_]) ->
if
X >= Live -> killed;
@@ -563,50 +566,51 @@ check_killed_block(_, []) -> transparent.
%%
%% (Unknown instructions will cause an exception.)
-check_used_block_fun(D) ->
- fun(R, Is) -> check_used_block(R, Is, D) end.
-
-check_used_block({x,X}=R, [{set,Ds,Ss,{alloc,Live,Op}}|Is], D) ->
+check_used_block({x,X}=R, [{set,Ds,Ss,{alloc,Live,Op}}|Is], St) ->
if
- X >= Live -> killed;
+ X >= Live -> {killed,St};
+ true -> check_used_block_1(R, Ss, Ds, Op, Is, St)
+ end;
+check_used_block(R, [{set,Ds,Ss,Op}|Is], St) ->
+ check_used_block_1(R, Ss, Ds, Op, Is, St);
+check_used_block(R, [{'%live',Live}|Is], St) ->
+ case R of
+ {x,X} when X >= Live -> {killed,St};
+ _ -> check_used_block(R, Is, St)
+ end;
+check_used_block(_, [], St) -> {transparent,St}.
+
+check_used_block_1(R, Ss, Ds, Op, Is, St0) ->
+ case member(R, Ss) of
true ->
- case member(R, Ss) orelse
- is_reg_used_at(R, Op, D) of
- true -> used;
- false ->
+ {used,St0};
+ false ->
+ case is_reg_used_at(R, Op, St0) of
+ {true,St} ->
+ {used,St};
+ {false,St} ->
case member(R, Ds) of
- true -> killed;
- false -> check_used_block(R, Is, D)
+ true -> {killed,St};
+ false -> check_used_block(R, Is, St)
end
end
- end;
-check_used_block(R, [{set,Ds,Ss,Op}|Is], D) ->
- case member(R, Ss) orelse
- is_reg_used_at(R, Op, D) of
- true -> used;
- false ->
- case member(R, Ds) of
- true -> killed;
- false -> check_used_block(R, Is, D)
- end
- end;
-check_used_block(R, [{'%live',Live}|Is], D) ->
- case R of
- {x,X} when X >= Live -> killed;
- _ -> check_used_block(R, Is, D)
- end;
-check_used_block(_, [], _) -> transparent.
+ end.
-is_reg_used_at(R, {gc_bif,_,{f,Lbl}}, D) ->
- is_reg_used_at_1(R, Lbl, D);
-is_reg_used_at(R, {bif,_,{f,Lbl}}, D) ->
- is_reg_used_at_1(R, Lbl, D);
-is_reg_used_at(_, _, _) -> false.
+is_reg_used_at(R, {gc_bif,_,{f,Lbl}}, St) ->
+ is_reg_used_at_1(R, Lbl, St);
+is_reg_used_at(R, {bif,_,{f,Lbl}}, St) ->
+ is_reg_used_at_1(R, Lbl, St);
+is_reg_used_at(_, _, St) ->
+ {false,St}.
-is_reg_used_at_1(_, 0, _) ->
- false;
-is_reg_used_at_1(R, Lbl, D) ->
- not is_not_used_at(R, Lbl, D).
+is_reg_used_at_1(_, 0, St) ->
+ {false,St};
+is_reg_used_at_1(R, Lbl, St0) ->
+ case check_liveness_at(R, Lbl, St0) of
+ {killed,St} -> {false,St};
+ {used,St} -> {true,St};
+ {unknown,St} -> {true,St}
+ end.
index_labels_1([{label,Lbl}|Is0], Acc) ->
Is = lists:dropwhile(fun({label,_}) -> true;
diff --git a/lib/compiler/test/andor_SUITE.erl b/lib/compiler/test/andor_SUITE.erl
index 0d00769704..4ffbe07e32 100644
--- a/lib/compiler/test/andor_SUITE.erl
+++ b/lib/compiler/test/andor_SUITE.erl
@@ -21,7 +21,8 @@
-export([all/0, suite/0,groups/0,init_per_suite/1, end_per_suite/1,
init_per_group/2,end_per_group/2,
t_case/1,t_and_or/1,t_andalso/1,t_orelse/1,inside/1,overlap/1,
- combined/1,in_case/1,before_and_inside_if/1]).
+ combined/1,in_case/1,before_and_inside_if/1,
+ slow_compilation/1]).
-include_lib("test_server/include/test_server.hrl").
@@ -472,6 +473,36 @@ before_and_inside_if_2(XDo1, XDo2, Do3) ->
end,
{CH1,CH2}.
+
+-record(state, {stack = []}).
+
+slow_compilation(_) ->
+ %% The function slow_compilation_1 used to compile very slowly.
+ ok = slow_compilation_1({a}, #state{}).
+
+slow_compilation_1(T1, #state{stack = [T2|_]})
+ when element(1, T2) == a, element(1, T1) == b, element(1, T1) == c ->
+ ok;
+slow_compilation_1(T, _)
+ when element(1, T) == a1; element(1, T) == b1; element(1, T) == c1 ->
+ ok;
+slow_compilation_1(T, _)
+ when element(1, T) == a2; element(1, T) == b2; element(1, T) == c2 ->
+ ok;
+slow_compilation_1(T, _) when element(1, T) == a ->
+ ok;
+slow_compilation_1(T, _)
+ when
+ element(1, T) == a,
+ (element(1, T) == b) and (element(1, T) == c) ->
+ ok;
+slow_compilation_1(_, T) when element(1, T) == a ->
+ ok;
+slow_compilation_1(_, T) when element(1, T) == b ->
+ ok;
+slow_compilation_1(T, _) when element(1, T) == a ->
+ ok.
+
%% Utilities.
check(V1, V0) ->