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-rw-r--r--lib/compiler/src/beam_bsm.erl6
-rw-r--r--lib/compiler/src/beam_dead.erl44
-rw-r--r--lib/compiler/src/beam_dict.erl13
3 files changed, 22 insertions, 41 deletions
diff --git a/lib/compiler/src/beam_bsm.erl b/lib/compiler/src/beam_bsm.erl
index 2a36fda1ea..5cc8252b99 100644
--- a/lib/compiler/src/beam_bsm.erl
+++ b/lib/compiler/src/beam_bsm.erl
@@ -651,10 +651,8 @@ add_warning(Term, Anno, Ws) ->
warning_translate_label(Term, D) when is_tuple(Term) ->
case element(1, Term) of
{label,F} ->
- case gb_trees:lookup(F, D) of
- none -> Term;
- {value,FA} -> setelement(1, Term, FA)
- end;
+ FA = gb_trees:get(F, D),
+ setelement(1, Term, FA);
_ -> Term
end;
warning_translate_label(Term, _) -> Term.
diff --git a/lib/compiler/src/beam_dead.erl b/lib/compiler/src/beam_dead.erl
index bb93110176..8e96569414 100644
--- a/lib/compiler/src/beam_dead.erl
+++ b/lib/compiler/src/beam_dead.erl
@@ -162,14 +162,11 @@ function({function,Name,Arity,CLabel,Is0}, Lc0) ->
%% We must split the basic block when we encounter instructions with labels,
%% such as catches and BIFs. All labels must be visible outside the blocks.
-%% Also remove empty blocks.
split_blocks({function,Name,Arity,CLabel,Is0}) ->
Is = split_blocks(Is0, []),
{function,Name,Arity,CLabel,Is}.
-split_blocks([{block,[]}|Is], Acc) ->
- split_blocks(Is, Acc);
split_blocks([{block,Bl}|Is], Acc0) ->
Acc = split_block(Bl, [], Acc0),
split_blocks(Is, Acc);
@@ -246,30 +243,24 @@ forward([{select_val,Reg,_,{list,List}}=I|Is], D0, Lc, Acc) ->
D = update_value_dict(List, Reg, D0),
forward(Is, D, Lc, [I|Acc]);
forward([{label,Lbl}=LblI,{block,[{set,[Dst],[Lit],move}|BlkIs]}=Blk|Is], D, Lc, Acc) ->
+ %% Assumption: The target labels in a select_val/3 instruction
+ %% cannot be reached in any other way than through the select_val/3
+ %% instruction (i.e. there can be no fallthrough to such label and
+ %% it cannot be referenced by, for example, a jump/1 instruction).
Block = case gb_trees:lookup({Lbl,Dst}, D) of
- {value,Lit} ->
- %% The move instruction seems to be redundant, but also make
- %% sure that the instruction preceeding the label
- %% cannot fall through to the move instruction.
- case is_unreachable_after(Acc) of
- false -> Blk; %Must keep move instruction.
- true -> {block,BlkIs} %Safe to remove move instruction.
- end;
- _ -> Blk %Keep move instruction.
+ {value,Lit} -> {block,BlkIs}; %Safe to remove move instruction.
+ _ -> Blk %Must keep move instruction.
end,
forward([Block|Is], D, Lc, [LblI|Acc]);
forward([{label,Lbl}=LblI|[{move,Lit,Dst}|Is1]=Is0], D, Lc, Acc) ->
+ %% Assumption: The target labels in a select_val/3 instruction
+ %% cannot be reached in any other way than through the select_val/3
+ %% instruction (i.e. there can be no fallthrough to such label and
+ %% it cannot be referenced by, for example, a jump/1 instruction).
Is = case gb_trees:lookup({Lbl,Dst}, D) of
- {value,Lit} ->
- %% The move instruction seems to be redundant, but also make
- %% sure that the instruction preceeding the label
- %% cannot fall through to the move instruction.
- case is_unreachable_after(Acc) of
- false -> Is0; %Must keep move instruction.
- true -> Is1 %Safe to remove move instruction.
- end;
- _ -> Is0 %Keep move instruction.
- end,
+ {value,Lit} -> Is1; %Safe to remove move instruction.
+ _ -> Is0 %Keep move instruction.
+ end,
forward(Is, D, Lc, [LblI|Acc]);
forward([{test,is_eq_exact,_,[Dst,Src]}=I,
{block,[{set,[Dst],[Src],move}|Bl]}|Is], D, Lc, Acc) ->
@@ -299,16 +290,12 @@ update_value_dict([Lit,{f,Lbl}|T], Reg, D0) ->
Key = {Lbl,Reg},
D = case gb_trees:lookup(Key, D0) of
none -> gb_trees:insert(Key, Lit, D0); %New.
- {value,Lit} -> D0; %Already correct.
{value,inconsistent} -> D0; %Inconsistent.
{value,_} -> gb_trees:update(Key, inconsistent, D0)
end,
update_value_dict(T, Reg, D);
update_value_dict([], _, D) -> D.
-is_unreachable_after([I|_]) ->
- beam_jump:is_unreachable_after(I).
-
%%%
%%% Scan instructions in reverse execution order and remove dead code.
%%%
@@ -602,16 +589,11 @@ count_bits_matched([{test,_,_,_}|Is], SavePoint, Bits) ->
count_bits_matched([{bs_save2,Reg,SavePoint}|_], {Reg,SavePoint}, Bits) ->
%% The save point we are looking for - we are done.
Bits;
-count_bits_matched([{bs_save2,_,_}|Is], SavePoint, Bits) ->
- %% Another save point - keep counting.
- count_bits_matched(Is, SavePoint, Bits);
count_bits_matched([_|_], _, Bits) -> Bits.
shortcut_bs_pos_used(To, Reg, D) ->
shortcut_bs_pos_used_1(beam_utils:code_at(To, D), Reg, D).
-shortcut_bs_pos_used_1([{bs_restore2,Reg,_}|_], Reg, _) ->
- false;
shortcut_bs_pos_used_1([{bs_context_to_binary,Reg}|_], Reg, _) ->
false;
shortcut_bs_pos_used_1(Is, Reg, D) ->
diff --git a/lib/compiler/src/beam_dict.erl b/lib/compiler/src/beam_dict.erl
index a503fcab38..c50ed28aa9 100644
--- a/lib/compiler/src/beam_dict.erl
+++ b/lib/compiler/src/beam_dict.erl
@@ -36,7 +36,6 @@
strings = <<>> :: binary(), %String pool
lambdas = [], %[{...}]
literals = dict:new() :: dict(), %Format: {Literal,Number}
- next_atom = 1 :: pos_integer(),
next_import = 0 :: non_neg_integer(),
string_offset = 0 :: non_neg_integer(),
next_literal = 0 :: non_neg_integer(),
@@ -66,13 +65,14 @@ highest_opcode(#asm{highest_opcode=Op}) -> Op.
%% atom(Atom, Dict) -> {Index,Dict'}
-spec atom(atom(), bdict()) -> {pos_integer(), bdict()}.
-atom(Atom, #asm{atoms=Atoms0,next_atom=NextIndex}=Dict) when is_atom(Atom) ->
+atom(Atom, #asm{atoms=Atoms0}=Dict) when is_atom(Atom) ->
case gb_trees:lookup(Atom, Atoms0) of
{value,Index} ->
{Index,Dict};
none ->
+ NextIndex = gb_trees:size(Atoms0) + 1,
Atoms = gb_trees:insert(Atom, NextIndex, Atoms0),
- {NextIndex,Dict#asm{atoms=Atoms,next_atom=NextIndex+1}}
+ {NextIndex,Dict#asm{atoms=Atoms}}
end.
%% Remembers an exported function.
@@ -139,7 +139,7 @@ lambda(Lbl, Index, OldUniq, NumFree, #asm{lambdas=Lambdas0}=Dict) ->
Lambdas = [{Lbl,{OldIndex,Lbl,Index,NumFree,OldUniq}}|Lambdas0],
{OldIndex,Dict#asm{lambdas=Lambdas}}.
-%% Returns the index for a literal (adding it to the atom table if necessary).
+%% Returns the index for a literal (adding it to the literal table if necessary).
%% literal(Literal, Dict) -> {Index,Dict'}
-spec literal(term(), bdict()) -> {non_neg_integer(), bdict()}.
@@ -156,14 +156,15 @@ literal(Lit, #asm{literals=Tab0,next_literal=NextIndex}=Dict) ->
%% atom_table(Dict) -> {LastIndex,[Length,AtomString...]}
-spec atom_table(bdict()) -> {non_neg_integer(), [[non_neg_integer(),...]]}.
-atom_table(#asm{atoms=Atoms,next_atom=NumAtoms}) ->
+atom_table(#asm{atoms=Atoms}) ->
+ NumAtoms = gb_trees:size(Atoms),
Sorted = lists:keysort(2, gb_trees:to_list(Atoms)),
Fun = fun({A,_}) ->
L = atom_to_list(A),
[length(L)|L]
end,
AtomTab = lists:map(Fun, Sorted),
- {NumAtoms-1,AtomTab}.
+ {NumAtoms,AtomTab}.
%% Returns the table of local functions.
%% local_table(Dict) -> {NumLocals, [{Function, Arity, Label}...]}
generated by cgit v1.2.3 (git 2.25.1) at 2025-07-02 19:43:00 +0000