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2016-03-14Prepare releaseErlang/OTP
2016-02-08Eliminate crash because of unsafe delaying of sub-binary creationBjörn Gustavsson
The following code would fail to compile: decode(<<Code/integer, Bin/binary>>) -> <<C1/integer, B1/binary>> = Bin, case C1 of X when X =:= 1 orelse X =:= 2 -> Bin2 = <<>>; _ -> Bin2 = B1 end, case Code of 1 -> decode(Bin2); _ -> Bin2 end. The error message would be: t: function decode/1+28: Internal consistency check failed - please report this bug. Instruction: return Error: {match_context,{x,0}}: The beam_bsm pass would delay the creation of a sub-binary when it was unsafe to do so. The culprit was the btb_follow_branch/3 function that for performance reasons cached labels that had already been checked. The problem was the safety of a label also depends on the contents of the registers. Therefore, the key for caching needs to be both the label and the register contents. Reported-by: José Valim
2016-01-14compiler, hipe: Fix pretty printing of Core MapsBjörn-Egil Dahlberg
Literal maps could cause dialyzer to crash when pretty printing the results. Reported-by: Chris McGrath <[email protected]>
2016-01-12Fix crash when attempting to update a fun as if it were a mapBjörn Gustavsson
The following example would cause an internal consistency failure in the compiler: f() -> ok. update() -> (fun f/0)#{u => 42}. The reason is that internally, v3_core will (incorrectly) rewrite update/0 to code similar to this: update() -> if is_map(fun f/0) -> maps:update(u, 42, fun f/0) end. Since funs are not allowed to be created in guards, incorrect and unsafe code would be generated. It is easy to fix the bug. There already is a is_valid_map_src/1 function in v3_core that tests whether the argument for the map update operation can possibly be a valid map. A fun is represented as a variable with a special name in Core Erlang, so it would not be recognized as unsafe. All we'll need to do to fix the bug is to look closer at variables to ensure they don't represent funs. That will ensure that the code is rewritten in the correct way: update() -> error({badmap,fun f/0}) end. Reported-by: Thomas Arts
2016-01-11Eliminate crash in v3_codegenBjörn Gustavsson
The following code would crash v3_codegen: order(From) -> catch if From#{[] => sufficient} -> saint end. Before explaining the crash, first some background on the stack frame and the Y registers. Certain instructions, most notably the 'call' instructions, clobber all X registers. Before any such instruction, all X registers that have values that will be used after the call must be saved to Y registers (i.e. to the stack frame). adjust_stack/4 will be called when X registers must be saved. There is also another situation when X registers must be saved, namely within a 'catch' if we are about to execute any instruction that may cause an exception. Examples of such instructions are some guard BIFs (such as length/1) and construction of binaries or maps. Within a 'catch', X registers must be be saved because if an exception is thrown and catched all X registers will be destroyed. The same adjust_stack/4 function will be called for those instructions, but only if they occur within a 'catch'. There is actually one more complication. If there is code in a guard within a catch, the X registers should not be saved, because the code in a guard never clobbers any X registers that were alive before the guard code was entered. v3_codegen is written with the implicit assumption that code in guards never cause anything to be saved to Y registers. The code for building maps and binaries would incorrectly save X registers within a guard inside a 'catch'. For construction of binaries, that would mean that a useless but harmelss 'move' instruction was generated. But for construction of maps, the saving of the Y register would not be harmless. There would be a crash when attempting to merge #sr{} records. #sr{} records keeps track of the contents of X and Y registers. When two separate code paths are joined (e.g. at the end of 'case' statement), the register descriptors must be reconciled. Basically, the register descriptors for both paths must be identical. The #sr{} record for one path must not claim that {y,0} contains a certain value, while another path claims that {y,0} is dead. Thus, the crash occurs in sr_merge/2 when failing to reconcile the Y registers. To fix this bug this bug we will introduce a new function called maybe_adjust_stack/5. It will save X registers on the stack only if the code is inside a catch but not inside a guard. We will change all existing code to use this new function when appropriate. Reported-by: Thomas Arts
2016-01-07beam_bool: Fix unsafe optimizationBjörn Gustavsson
beam_bool would make the following code unsafe (which would be reported by beam_validator): scotland(Echo) -> found(case Echo of Echo when true; Echo, Echo, Echo -> Echo; echo -> [] end, Echo = placed). found(_, _) -> million. Basically, beam_bool would see that the 'case' would always return the value of Echo. Thus: scotland(Echo) -> found(Echo, Echo = placed). The only problem is that beam_bool would also remove a 'move' instruction that would save Echo to the stack. Here is the assembly code for part of the function: {allocate_zero,1,1}. {move,{x,0},{y,0}}. %% Save Echo on stack. {bif,'=:=',{f,7},[{x,0},{atom,true}],{x,1}}. {bif,'=:=',{f,7},[{x,0},{atom,true}],{x,2}}. {bif,'=:=',{f,7},[{x,0},{atom,true}],{x,3}}. {bif,'and',{f,7},[{x,2},{x,3}],{x,2}}. {bif,'and',{f,7},[{x,1},{x,2}],{x,1}}. {jump,{f,8}}. {label,7}. {move,{atom,false},{x,1}}. {label,8}. {bif,'or',{f,6},[{atom,true},{x,1}],{x,1}}. {test,is_eq_exact,{f,6},[{x,1},{atom,true}]}. %% Jump never taken. {jump,{f,5}}. {label,6}. {test,is_eq_exact,{f,9},[{x,0},{atom,echo}]}. {move,nil,{x,0}}. {jump,{f,5}}. {label,9}. {test_heap,3,0}. {put_tuple,2,{x,0}}. {put,{atom,case_clause}}. {put,{y,0}}. {line,[{location,"t.erl",5}]}. {call_ext,1,{extfunc,erlang,error,1}}. {jump,{f,5}}. {label,5}. {test,is_eq_exact,{f,12},[{atom,placed},{y,0}]}. beam_bool would see that the is_eq_exact test at label 8 would always succeed. It could therefore remove most of the code before the jump to label 5. Unfortunately it also removed the essential move of Echo to the stack: {allocate_zero,1,1}. %% Instruction incorrectly removed: {move,{x,0},{y,0}}. {jump,{f,5}}. {label,5}. {test,is_eq_exact,{f,12},[{atom,placed},{y,0}]}. The root cause of the problem is that the 'move' instruction is included in the block of 'bif' instructions before label 8. Normally the 'move' instruction would not have been discarded, but because the left operand to the 'or' BIF is 'true', the entire block with 'bif' instructions are dropped. As far as I can see, there is no gain by including 'move' instructions in the first place. There is no way that better code will be produced. In fact, the entire optimization can be given up if 'move' instructions are found in the block. Thus we can fix this bug by never including any 'move' instructions in the block of 'bif' instructions. We can also remove all the code that deals with 'move' instructions within blocks. Reported-by: Thomas Arts
2015-12-15Update release notesErlang/OTP
2015-12-15Update version numbersErlang/OTP
2015-11-20Fix missing filename and line number in warningBjörn Gustavsson
When the 'bin_opt_info' is given, warnings without filenames and line numbers could sometimes be produced: no_file: Warning: INFO: matching non-variables after a previous clause matching a variable will prevent delayed sub binary optimization The reason for the missing information is that #c_alias{} records lack location information. There are several ways to fix the problem. The easiest seems to be to get the location information from the code). Noticed-by: José Valim
2015-11-17[compiler] Correct documentationHans Bolinder
Fix mistakes found by 'xmllint'.
2015-10-26Fix cerl_trees:label/2 bug with map K/V swapMagnus Lång
2015-09-21Prepare releaseErlang/OTP
2015-09-14Merge branch 'bjorn/cuddle-with-tests' into maintBjörn Gustavsson
* bjorn/cuddle-with-tests: (23 commits) rand_SUITE: Speed up basic_stats/1 base64_SUITE: Speed up roundtrip/1 lists_SUITE: Test lists:concat/2 lists_SUITE: Test lists:split/2 lists_SUITE: Add a test case for lists:prefix/2 lists_SUITE: Add hof/1 to test all high-order functions lists_SUITE: Add test for lists:takewhile/1 lists_SUITE: Run test cases in each group in parallel lists_SUITE: Test lists:keyreplace/4 lists_SUITE: Extend flatten/1 test to also test flatlength/1 lists_SUITE: Correct test of lists:flatten/2 id_transform_SUITE: Modernize test suite io_proto_SUITE: Speed up determination of default shell io_proto_SUITE: Refactor up rtnode() and friends gen_event_SUITE: Remove unnecessary sleep calls proc_lib: Improve coverage for crash/1 proc_lib_SUITE: Eliminate compiler warnings io_SUITE: Add coverage/1 to completely cover io_lib_pretty io_SUITE: Extend coverage of code for testing printable chars io_SUITE: Speed up test for bad +pc option ...
2015-09-11Merge branch 'c-rack/fix-typo3' into maintZandra
* c-rack/fix-typo3: Fix typo in call_last/3 spec Fix typo Fix typo: message to send is in x(1) not x(0) Fix another small typo Fix typo
2015-09-10compile_SUITE: Add test of warningsBjörn Gustavsson
Make sure that all warnings produced when compiling the test suite contains filenames and line numbers.
2015-09-04compiler: Fix get_map_elements register corruptionBjörn-Egil Dahlberg
Instruction get_map_elements might destroy target registers when the fail-label is taken. Only seen for patterns with two, and only two, target registers. Specifically: we copy one register, and then jump. foo(A,#{a := V1, b := V2}) -> ... foo(A,#{b := V}) -> ... call foo(value, #{a=>whops, c=>42}). corresponding assembler: {test,is_map,{f,5},[{x,1}]}. {get_map_elements,{f,7},{x,1},{list,[{atom,a},{x,1},{atom,b},{x,2}]}}. %% if 'a' exists but not 'b' {x,1} is overwritten, jump {f,7} {move,{integer,1},{x,0}}. {call_only,3,{f,10}}. {label,7}. {get_map_elements,{f,8},{x,1},{list,[{atom,b},{x,2}]}}. %% {x,1} (src) is read with a corrupt value {move,{x,0},{x,1}}. {move,{integer,2},{x,0}}. {call_only,3,{f,10}}. The fix is to remove 'opt_moves' pass for get_map_elements instruction in the case of two or more destinations. Reported-by: Valery Tikhonov
2015-09-04compiler: Add extra checks for get_map_elements in validatorBjörn-Egil Dahlberg
2015-09-04compiler: Add test for corrupt register in get_map_elementsBjörn-Egil Dahlberg
2015-08-28Fix typo in call_last/3 specConstantin Rack
2015-08-25Fix typoConstantin Rack
2015-08-24Fix typo: message to send is in x(1) not x(0)Constantin Rack
2015-08-09Fix another small typoConstantin Rack
2015-08-09Fix typoConstantin Rack
2015-06-23Prepare releaseErlang/OTP
2015-06-22fix errors caused by changed line numbersBruce Yinhe
2015-06-18Change license text to APLv2Bruce Yinhe
2015-06-17compiler: Add regressions_SUITEBjörn-Egil Dahlberg
regressions_SUITE will have code snippets which previously crashed the compiler. This commits includes a test for Maps crash in beam_bool.
2015-06-17compiler: Fix beam_bool pass for get_map_elementsBjörn-Egil Dahlberg
Before beam_split the get_map_elements instruction is still in blocks and the helper function in beam_jump did not reflect this. Reported-by: Quviq twitter account
2015-06-04Merge branch 'bjorn/compiler/spurious-warning'Björn Gustavsson
* bjorn/compiler/spurious-warning: sys_core_fold: Eliminate warnings for unused terms in effect context sys_core_fold: Eliminate warnings for unused terms
2015-05-27Merge branch 'bjorn/compiler/doc'Björn Gustavsson
* bjorn/compiler/doc: Update compiler documentation (Sneaking in OTP-12769 here which is a release note for syntax_tools. Sorry about that.)
2015-05-27Update compiler documentationBjörn Gustavsson
Language cleaned up by the technical writer tmanevik from Combitech. Proofreading and corrections by Björn Gustavsson.
2015-05-27Update application versionsHans Bolinder
2015-05-26Merge branch 'egil/opt-compile-time/OTP-12774'Björn-Egil Dahlberg
* egil/opt-compile-time/OTP-12774: stdlib: Relax erl_anno_SUITE:is_anno/1 test Update primary bootstrap compiler: Use Maps as type information compiler: Use Maps instead of dict in beam_jump compiler: Use cerl_sets instead of gb_sets in beam_type compiler: Use Maps instead of gb_trees in beam_dead compiler: Use cerl_sets instead of gb_sets in beam_jump compiler: Use cerl_sets instead of sets in v3_kernel compiler: Use cerl_sets instead of gb_sets in sys_core_fold compiler: Add cerl_sets module compiler: Scope uses gb_sets not gb_trees beam_dict: Use Maps to map function name indices beam_dict: Use Maps to map line indices beam_dict: Use Maps to map atom indices v3_codegen: Use Maps to map local functions v3_life: Refactor variable db compiler: Use lc instead of map/1 in v3_codegen stdlib: Optimize erl_anno:is_string/1 Conflicts: bootstrap/lib/kernel/ebin/inet_dns.beam bootstrap/lib/stdlib/ebin/erl_anno.beam bootstrap/lib/stdlib/ebin/erl_lint.beam
2015-05-22sys_core_fold: Eliminate warnings for unused terms in effect contextBjörn Gustavsson
The optimization introduced in 0a0d39d351fc could cause spurious warnings of the type: "a term is constructed, but never used". That would happen for constructs in effect context. To avoid those warnings, we will need to apply warning suppression also in effect context.
2015-05-22Merge branch 'egil/fix-compiler-beam_bsm/OTP-12758'Björn-Egil Dahlberg
* egil/fix-compiler-beam_bsm/OTP-12758: compiler: Add tests for beam_bsm get_map_elements compiler: Teach beam_bsm get_map_elements instruction
2015-05-21compiler: Use Maps as type informationBjörn-Egil Dahlberg
Using Maps as type information container speedups files like cow_http_hd.erl by ~500ms. Previously spent ~60% of the time in orddict:store/3.
2015-05-21compiler: Use Maps instead of dict in beam_jumpBjörn-Egil Dahlberg
2015-05-21compiler: Use cerl_sets instead of gb_sets in beam_typeBjörn-Egil Dahlberg
2015-05-21compiler: Use Maps instead of gb_trees in beam_deadBjörn-Egil Dahlberg
2015-05-21compiler: Use cerl_sets instead of gb_sets in beam_jumpBjörn-Egil Dahlberg
2015-05-21compiler: Use cerl_sets instead of sets in v3_kernelBjörn-Egil Dahlberg
2015-05-21compiler: Use cerl_sets instead of gb_sets in sys_core_foldBjörn-Egil Dahlberg
2015-05-21compiler: Add cerl_sets moduleBjörn-Egil Dahlberg
A sets implementation based on maps.
2015-05-21compiler: Scope uses gb_sets not gb_treesBjörn-Egil Dahlberg
2015-05-21beam_dict: Use Maps to map function name indicesBjörn-Egil Dahlberg
2015-05-21beam_dict: Use Maps to map line indicesBjörn-Egil Dahlberg
2015-05-21beam_dict: Use Maps to map atom indicesBjörn-Egil Dahlberg
2015-05-21v3_codegen: Use Maps to map local functionsBjörn-Egil Dahlberg
2015-05-21v3_life: Refactor variable dbBjörn-Egil Dahlberg
2015-05-21compiler: Use lc instead of map/1 in v3_codegenBjörn-Egil Dahlberg
Small speed increase for large files.