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authorBjörn Gustavsson <[email protected]>2018-09-26 14:11:09 +0200
committerBjörn Gustavsson <[email protected]>2018-09-28 14:33:52 +0200
commitb6f06edde9645bf96a4bc7ebb1e0965fc8b177d6 (patch)
tree29fc947e4015f866de4309d53e3de968993eea7a /lib/compiler
parent7d941c529dc9db016af30cdace2df089d1648dbf (diff)
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Fix code generation of binary instructions with the r21 option
OTP 22 extends the binary instructions to support a Y register destination. When giving an option to compile for an earlier release, make sure that binary instructions don't use a Y register destination, by rewriting the binary instructions to use an X register destination and adding a `move` instruction to move the value to the Y register.
Diffstat (limited to 'lib/compiler')
-rw-r--r--lib/compiler/src/beam_ssa_pre_codegen.erl57
-rw-r--r--lib/compiler/test/Makefile1
2 files changed, 58 insertions, 0 deletions
diff --git a/lib/compiler/src/beam_ssa_pre_codegen.erl b/lib/compiler/src/beam_ssa_pre_codegen.erl
index 36137ef046..f7fe67f526 100644
--- a/lib/compiler/src/beam_ssa_pre_codegen.erl
+++ b/lib/compiler/src/beam_ssa_pre_codegen.erl
@@ -131,6 +131,10 @@ passes(Opts) ->
?PASS(find_yregs),
?PASS(reserve_yregs),
+ %% Handle legacy binary match instruction that don't
+ %% accept a Y register as destination.
+ ?PASS(legacy_bs),
+
%% Improve reuse of Y registers to potentially
%% reduce the size of the stack frame.
?PASS(copy_retval),
@@ -612,6 +616,59 @@ bs_subst_ctx(#b_var{}=Var, CtxChain) ->
bs_subst_ctx(Other, _CtxChain) ->
Other.
+%% legacy_bs(St0) -> St.
+%% Binary matching instructions in OTP 21 and earlier don't support
+%% a Y register as destination. If St#st.use_bsm3 is false,
+%% we will need to rewrite those instructions so that the result
+%% is first put in an X register and then moved to a Y register
+%% if the operation succeeded.
+
+legacy_bs(#st{use_bsm3=false,ssa=Blocks0,cnt=Count0,res=Res}=St) ->
+ IsYreg = maps:from_list([{V,true} || {V,{y,_}} <- Res]),
+ Linear0 = beam_ssa:linearize(Blocks0),
+ {Linear,Count} = legacy_bs(Linear0, IsYreg, Count0, #{}, []),
+ Blocks = maps:from_list(Linear),
+ St#st{ssa=Blocks,cnt=Count};
+legacy_bs(#st{use_bsm3=true}=St) -> St.
+
+legacy_bs([{L,Blk}|Bs], IsYreg, Count0, Copies0, Acc) ->
+ #b_blk{is=Is0,last=Last} = Blk,
+ Is1 = case Copies0 of
+ #{L:=Copy} -> [Copy|Is0];
+ #{} -> Is0
+ end,
+ {Is,Count,Copies} = legacy_bs_is(Is1, Last, IsYreg, Count0, Copies0, []),
+ legacy_bs(Bs, IsYreg, Count, Copies, [{L,Blk#b_blk{is=Is}}|Acc]);
+legacy_bs([], _IsYreg, Count, _Copies, Acc) ->
+ {Acc,Count}.
+
+legacy_bs_is([#b_set{op=Op,dst=Dst}=I0,
+ #b_set{op=succeeded,dst=SuccDst,args=[Dst]}=SuccI0],
+ Last, IsYreg, Count0, Copies0, Acc) ->
+ NeedsFix = is_map_key(Dst, IsYreg) andalso
+ case Op of
+ bs_get -> true;
+ bs_init -> true;
+ _ -> false
+ end,
+ case NeedsFix of
+ true ->
+ TempDst = #b_var{name={'@bs_temp_dst',Count0}},
+ Count = Count0 + 1,
+ I = I0#b_set{dst=TempDst},
+ SuccI = SuccI0#b_set{args=[TempDst]},
+ Copy = #b_set{op=copy,dst=Dst,args=[TempDst]},
+ #b_br{bool=SuccDst,succ=SuccL} = Last,
+ Copies = Copies0#{SuccL=>Copy},
+ legacy_bs_is([], Last, IsYreg, Count, Copies, [SuccI,I|Acc]);
+ false ->
+ legacy_bs_is([], Last, IsYreg, Count0, Copies0, [SuccI0,I0|Acc])
+ end;
+legacy_bs_is([I|Is], Last, IsYreg, Count, Copies, Acc) ->
+ legacy_bs_is(Is, Last, IsYreg, Count, Copies, [I|Acc]);
+legacy_bs_is([], _Last, _IsYreg, Count, Copies, Acc) ->
+ {reverse(Acc),Count,Copies}.
+
%% sanitize(St0) -> St.
%% Remove constructs that can cause problems later:
%%
diff --git a/lib/compiler/test/Makefile b/lib/compiler/test/Makefile
index e56594f344..40428b7f2d 100644
--- a/lib/compiler/test/Makefile
+++ b/lib/compiler/test/Makefile
@@ -98,6 +98,7 @@ INLINE= \
record
R21= \
+ bs_construct \
bs_match
CORE_MODULES = \