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authorBjörn Gustavsson <[email protected]>2015-10-05 06:43:12 +0200
committerBjörn Gustavsson <[email protected]>2015-10-05 12:47:55 +0200
commit76bb9f0e9a0b36ea7c9720c2bf90f6b52a4eabf8 (patch)
tree47e29acaeafb5025531d8736ffb7ded30cf678a3
parent7dd616c1832c54370be7f796a4b6578a8d9aedd9 (diff)
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beam_reorder: Eliminate compiler crash
c288ab87 added beam_reorder to move get_tuple_element instructions. Compiling code such as the following would crash the compiler: alloc(_U1, _U2, R) -> V = R#alloc.version, Res = id(V), _ = id(0), Res. The crash would occur because the following two instructions: {get_tuple_element,{x,2},1,{x,1}}. {allocate_zero,1,2}. were swapped and rewritten to: {allocate_zero,1,1}. {get_tuple_element,{x,2},1,{x,1}}. That transformation is not safe because the allocate_zero instruction would kill {x,2}, which is the register that is holding the reference to the tuple. Only do the transformation when the tuple reference is in an x register with a lower number than the destination register.
-rw-r--r--lib/compiler/src/beam_reorder.erl21
-rw-r--r--lib/compiler/test/Makefile2
-rw-r--r--lib/compiler/test/beam_reorder_SUITE.erl69
3 files changed, 84 insertions, 8 deletions
diff --git a/lib/compiler/src/beam_reorder.erl b/lib/compiler/src/beam_reorder.erl
index 70adca6b04..41586a7bf2 100644
--- a/lib/compiler/src/beam_reorder.erl
+++ b/lib/compiler/src/beam_reorder.erl
@@ -110,14 +110,19 @@ reorder_1([{test,_,{f,L},Ss}=I|Is0], D0,
end
end
end;
-reorder_1([{allocate_zero,N,Live}|Is], D,
- [{get_tuple_element,_,_,{x,X}}=G|Acc])
- when X+1 =:= Live ->
- %% Move allocation instruction upwards past get_tuple_element
- %% instructions to give more opportunities for moving
- %% get_tuple_element instructions.
- I = {allocate_zero,N,X},
- reorder_1([I,G|Is], D, Acc);
+reorder_1([{allocate_zero,N,Live}=I0|Is], D,
+ [{get_tuple_element,{x,Tup},_,{x,Dst}}=G|Acc]=Acc0) ->
+ case Tup < Dst andalso Dst+1 =:= Live of
+ true ->
+ %% Move allocation instruction upwards past
+ %% get_tuple_element instructions to create more
+ %% opportunities for moving get_tuple_element
+ %% instructions.
+ I = {allocate_zero,N,Dst},
+ reorder_1([I,G|Is], D, Acc);
+ false ->
+ reorder_1(Is, D, [I0|Acc0])
+ end;
reorder_1([I|Is], D, Acc) ->
reorder_1(Is, D, [I|Acc]);
reorder_1([], _, Acc) -> reverse(Acc).
diff --git a/lib/compiler/test/Makefile b/lib/compiler/test/Makefile
index 0cd8618730..400565100f 100644
--- a/lib/compiler/test/Makefile
+++ b/lib/compiler/test/Makefile
@@ -11,6 +11,7 @@ MODULES= \
beam_validator_SUITE \
beam_disasm_SUITE \
beam_except_SUITE \
+ beam_reorder_SUITE \
beam_type_SUITE \
beam_utils_SUITE \
bs_bincomp_SUITE \
@@ -44,6 +45,7 @@ NO_OPT= \
andor \
apply \
beam_except \
+ beam_reorder \
beam_type \
beam_utils \
bs_construct \
diff --git a/lib/compiler/test/beam_reorder_SUITE.erl b/lib/compiler/test/beam_reorder_SUITE.erl
new file mode 100644
index 0000000000..4b2262f65b
--- /dev/null
+++ b/lib/compiler/test/beam_reorder_SUITE.erl
@@ -0,0 +1,69 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2015. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%% http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% %CopyrightEnd%
+%%
+-module(beam_reorder_SUITE).
+
+-export([all/0,suite/0,groups/0,init_per_suite/1,end_per_suite/1,
+ init_per_group/2,end_per_group/2,
+ alloc/1]).
+
+suite() -> [{ct_hooks,[ts_install_cth]}].
+
+all() ->
+ test_lib:recompile(?MODULE),
+ [{group,p}].
+
+groups() ->
+ [{p,[parallel],
+ [alloc
+ ]}].
+
+init_per_suite(Config) ->
+ Config.
+
+end_per_suite(_Config) ->
+ ok.
+
+init_per_group(_GroupName, Config) ->
+ Config.
+
+end_per_group(_GroupName, Config) ->
+ Config.
+
+-record(alloc, {version}).
+
+alloc(_Config) ->
+ {ok,42} = alloc_a(1, 2, #alloc{version=42}),
+ {a,b,c} = alloc_b(1, 2, #alloc{version={a,b,c}}),
+ ok.
+
+alloc_a(_U1, _U2, R) ->
+ V = R#alloc.version,
+ Res = id({ok,V}),
+ _ = id(0),
+ Res.
+
+alloc_b(_U1, _U2, R) ->
+ V = R#alloc.version,
+ Res = id(V),
+ _ = id(0),
+ Res.
+
+id(I) ->
+ I.