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2017-08-31Eliminate unnecessary 'move' instructionsBjörn Gustavsson
The compiler could sometimes emit unnecessary 'move' instructions in the code for binary matching, for example for this function: escape(<<Byte, Rest/bits>>, Pos) when Byte >= 127 -> escape(Rest, Pos + 1); escape(<<Byte, Rest/bits>>, Pos) -> escape(Rest, Pos + Byte); escape(<<_Rest/bits>>, Pos) -> Pos. The generated code would look like this: {function, escape, 2, 2}. {label,1}. {line,[{location,"t.erl",17}]}. {func_info,{atom,t},{atom,escape},2}. {label,2}. {test,bs_start_match2,{f,1},2,[{x,0},0],{x,0}}. {test,bs_get_integer2, {f,4}, 2, [{x,0}, {integer,8}, 1, {field_flags,[{anno,[17,{file,"t.erl"}]},unsigned,big]}], {x,2}}. {'%',{bin_opt,[17,{file,"t.erl"}]}}. {move,{x,0},{x,3}}. %% UNECESSARY! {test,is_ge,{f,3},[{x,2},{integer,127}]}. {line,[{location,"t.erl",18}]}. {gc_bif,'+',{f,0},4,[{x,1},{integer,1}],{x,1}}. {move,{x,3},{x,0}}. %% UNECESSARY! {call_only,2,{f,2}}. {label,3}. {line,[{location,"t.erl",20}]}. {gc_bif,'+',{f,0},4,[{x,1},{x,2}],{x,1}}. {move,{x,3},{x,0}}. %% UNECESSARY! {call_only,2,{f,2}}. {label,4}. {move,{x,1},{x,0}}. return. The redundant 'move' instructions have been marked. To avoid the 'move' instructions, we can extend the existing function is_context_unused/1 in v3_codegen. If v3_codegen can know that the match context will not be used again, it can reuse the register for the match context and avoid the extra 'move' instructions. https://bugs.erlang.org/browse/ERL-444
2017-08-31Merge branch 'maint'Björn Gustavsson
* maint: Make handling of match contexts stricter
2017-08-30Merge pull request #1530 from michalmuskala/beam-peep-optBjörn Gustavsson
Enhance optimisations in beam_peep
2017-08-30Make handling of match contexts stricterBjörn Gustavsson
beam_validator could fail issue a diagnostic when a register that was supposed to be a match context was not guaranteed to be a match context. The bug was in merging of types. Merging of a match context with another term would result in a match context. That is wrong. Merging should produce a more general type, not a narrower type. Also, the valid slots in two match contexts should be combined with 'band', not 'bor'.
2017-08-26Enhance optimisations in beam_peepMichał Muskała
When cleaning selects, it might happen we're left with only one pair. In such case convert to a regular test + jump.
2017-08-22Merge branch 'maint'Lukas Larsson
2017-08-22Merge branch ↵Lukas Larsson
'john/compiler/fail-labels-in-blocks-otp-18/ERIERL-48/OTP-14522' into maint * john/compiler/fail-labels-in-blocks-otp-18/ERIERL-48/OTP-14522: compiler: Fix live regs update on allocate in validator Take fail labels into account when determining liveness in block ops Conflicts: lib/compiler/src/beam_utils.erl
2017-08-16compiler: Fix live regs update on allocate in validatorLukas Larsson
The state without pruned registers was passed on to test_heap causing the validator to belive registers that aren't live actually are live.
2017-08-16Merge pull request #1528 from ↵Björn Gustavsson
bjorng/bjorn/compiler/improve-case-opt/ERL-452/OTP-14525 Generalize optimization of "one-armed" cases
2017-08-14Apply the redundant test optimisation also in case of fall-throughMichał Muskała
Even though, it's not possible to have fall-throughs when entering the otp pass, it can produce them itself and we're running the pass until fixpoint.
2017-08-14Replace labels instead of inserting duplicates in beam_jumpMichał Muskała
This makes other optimisations more efficient since we have less labels overall.
2017-08-14Enhance elimination of useless tests in beam_jumpMichał Muskała
It can happen we have the following situation: {test,is_tuple,Fail,[R1]} {test,test_arity,Fail,[R1,N1]} {get_tuple_element,R1,N2,R2} {test,is_eq_exaqct,Fail,[R2,Atom]} {jump,Fail} Previously, the optimisation would eliminate the last is_eq_exact test, but we can do more. If the register R2 is not used in Fail, we can eliminate the get_tuple_element instruction as well as all the preceding tests. Ultimately, the whole sequence can be replaced by: {jump,Fail}
2017-08-13Run the sharing optimisation in beam_jump until fixpointMichał Muskała
This is especially useful after inlining a function with a case. Today the compiler would most probably be able to unify all the leafs of the case during the sharing optimisation, but it would fail to unify the pattern matching itself. Naively running the optimisation multiple times wouldn't be able to find the common code either, because it would differ in jump/fail targets of various instructions. To remedy this, after doing each sharing pass we traverse the code backwards when reversing and update all the jump targets with the new targets that were discovered during the unification pass. This allows running the optimisation until fixpoint and makes sure all sharing opportunities will be discovered. This optimisation also helps with the Elixir's `with/else` construct.
2017-08-12Introduce beam_utils:replace_labels/4Michał Muskała
2017-08-10Merge branch 'maint'Björn Gustavsson
* maint: sys_core_fold: Fix unsafe optimization of non-variable apply Correct type specification in ssl:prf/5
2017-08-10Generalize optimization of "one-armed" casesBjörn Gustavsson
A 'case' expression will force a stack frame (essentially in the same way as a function call), unless it is at the end of a function. In sys_core_fold there is an optimization that can optimize one-armed cases such as: case Expr of Pat1 -> DoSomething; Pat2 -> erlang:error(bad) end, MoreCode. Because only one arm of the 'case' can succeed, the code after the case can be move into the successful arm: case Expr of Pat1 -> DoSomething, MoreCode; Pat2 -> erlang:error(bad) end. Thus, the 'case' is at the end of the function and it will no longer need a stack frame. However, the optimization in sys_core_fold would not be applied if there were more than one failing clause such as in this code: case Expr of Pat1 -> DoSomething, MoreCode; Pat2 -> erlang:error(bad); _ -> erlang:error(case_clause) end. Generalize the optimization to handle any number of failing clauses at the end of the case. Reported-by: bugs.erlang.org/browse/ERL-452
2017-08-07Take fail labels into account when determining liveness in block opsJohn Högberg
2017-08-07sys_core_fold: Fix unsafe optimization of non-variable applyBjörn Gustavsson
The sys_core_fold pass would do an unsafe "optimization" when an apply operation did not have a variable in the function position as in the following example: > cat test1.core module 'test1' ['test1'/2] attributes [] 'i'/1 = fun (_f) -> _f 'test1'/2 = fun (_f, _x) -> apply apply 'i'/1 (_f) (_x) end > erlc test1.core no_file: Warning: invalid function call Reported-by: Mikael Pettersson
2017-07-07Merge pull request #1080 from josevalim/jv-sys-core-replaceBjörn Gustavsson
Introduce a new core pass called sys_core_alias OTP-14505
2017-07-06Introduce a new core pass called sys_core_aliasJosé Valim
The goal of this pass is to find values that are built from patterns and generate aliases for those values to remove pressure from the GC. For example, this code: example({ok, Val}) -> {ok, Val}. shall become: example({ok, Val} = Tuple) -> Tuple. Currently this pass aliases tuple and cons nodes made of literals, variables and other cons. The tuple/cons may appear anywhere in the pattern and it will be aliased if used later on. Notice a tuple/cons made only of literals is not aliased as it may be part of the literal pool.
2017-07-04Make tuple calls opt-inJosé Valim
Tuple calls is the ability to invoke a function on a tuple as first argument: 1> Var = dict:new(). {dict,0,16,16,8,80,48, {[],[],[],[],[],[],[],[],[],[],[],[],[],[],[],[]}, {{[],[],[],[],[],[],[],[],[],[],[],[],[],[],[],[]}}} 2> Var:size(). 0 This behaviour is considered by most to be undesired and confusing, especially when it comes to errors. For example, imagine you invoke "Mod:new()" where a Mod is an atom and you accidentally pass {ok, dict}. It raises: {undef,[{ok,new,[{ok,dict}],[]},...]} As it attempts to invoke ok:new/1, which is really hard to debug as there is no call to new/1 on the source code. Furthemore, this behaviour is implemented at the VM level, which imposes such semantics on all languages running on BEAM. Since we cannot remove the behaviour above, this proposal makes the behaviour opt-in with a compiler flag: -compile(tuple_calls). This means that, if a codebase relies on this functionality, they can keep compatibility by adding configuring their build tool to always use the 'tuple_calls' flag or explicitly on each module. As long as the compile attribute above is listed, the codebase will work on old and new Erlang versions alike. The only downside of the current implementation is that modules compiled on OTP 20 that rely on 'tuple_calls' will have to be recompiled to run with 'tuple_calls' on OTP 21+.
2017-06-14Update copyright yearHans Nilsson
2017-06-13v3_kernel: Keep orddicts sortedBjörn Gustavsson
2017-06-13sys_core_fold: Ensure that orddict keys are uniqueBjörn Gustavsson
All keys in an orddict must be unique. sys_core_fold:sub_sub_scope/1 broke that rule. It was probably harmless, but it is better to avoid such rule violations.
2017-06-12Merge branch 'hasse/unicode_atoms/OTP-14285'Hans Bolinder
* hasse/unicode_atoms/OTP-14285: compiler: Handle (bad) Unicode parse transform module names kernel: Improve handling of Unicode filenames stdlib: Handle Unicode atoms in ms_transform stdlib: Improve Unicode handling of the Erlang parser stdlib: Handle unknown compiler options with Unicode stdlib: Handle Unicode macro names stdlib: Correct Unicode handling in escript dialyzer: Improve handling of Unicode parsetools: Improve handling of Unicode atoms stdlib: Handle Unicode atoms when formatting stacktraces stdlib: Add more checks of module names to the linter stdlib: Handle Unicode atoms better in io_lib_format stdlib: Handle Unicode atoms in c.erl
2017-06-12compiler: Handle (bad) Unicode parse transform module namesHans Bolinder
2017-06-07Fix unsafe bit syntax matching optimizationBjörn Gustavsson
As part of sys_core_fold, variables involved in bit syntax matching would be annotated when it would be safe for a later pass to do the delayed sub-binary creation optimization. An implicit assumption regarding the annotation was that the code must not be further optimized. That assumption was broken in 05130e48555891, which introduced a fixpoint iteration (applying the optimizations until there were no more changes). That means that a variable could be annotated as safe for reusing the match context in one iteration, but a later iteration could rewrite the code in a way that would make the optimization unsafe. One way to fix this would be to clear all reuse_for_context annotations before each iteration. But that would be wasteful. Instead I chose to fix the problem by moving out the annotation code to a separate pass (sys_core_bsm) that is run later after all major optimizations of Core Erlang has been done.
2017-05-23Correct handling of module name in compile:forms/1,2Björn Gustavsson
compile:forms/1,2 is documented to return: {ok,ModuleName,BinaryOrCode} However, if one of the options 'from_core', 'from_asm', or 'from_beam' is given, ModuleName will be returned as []. A worse problem is that is that if one those options are combined with the 'native' option, compilation will crash. Correct compile:forms/1,2 to pick up the module name from the forms provided (either Core Erlang, Beam assembly code, or a Beam file). Reported here: https://bugs.erlang.org/browse/ERL-417
2017-05-19genop.tab: Add an OTP 20 commentBjörn Gustavsson
Make it clear that is_tagged_tuple/4 was added in OTP 20 (not R17).
2017-05-10erl_bifs: Remove pure BIFs serving no useful purposeBjörn Gustavsson
Functions that can are known be pure can be evaluated at compile-time if the arguments are literals and if the result is expressible as a literal. list_to_ref/1 and list_to_port/1 returns terms that cannot be expressed as literals, so the optimization is not possible. The argument for port_to_list/1 is never a literal, so there is no way to evaluate it at compile-time. Therefore, marking those functions as pure serves no useful purpose. Note: list_to_pid/1 *is* marked as pure, but only so that we can test the code in sys_core_fold that rejects pure functions that evaluate to at term that is not possible to express as a literal. It is sufficient to have one pure function of that kind.
2017-05-10erl_bifs: Remove erlang:hash/2 from list of pure functionsBjörn Gustavsson
erlang:hash/2 was removed in c5d9b970fb5b3a71.
2017-05-09Merge pull request #1439 from josevalim/jv-atu8-functionBjörn Gustavsson
Add a test for utf8 function names
2017-05-08Add a test for utf8 function namesJosé Valim
The test found a bug in v3_kernel_pp which was not taking into account utf8 atoms. The bug has also been fixed.
2017-05-05Make 'slim' slim againBjörn Gustavsson
The undocumented compiler option 'slim' is used when compiling the primary bootstrap. The purpose is to make the bootstrap smaller and to avoid unnecessary churn in the git repository. That is, the BEAM file should be different only if the actual code in the file is different, and not if it has merely been re-compiled on a different computer. Two commits have fattened the 'slim' option. In 36f7087ae0f, extra chunks are included even in slim BEAM files. In dfb899c0229f7, the "Dbgi" were added as an extra chunk, causing it to be included in slim files. Make 'slim' slim again by only including the essential chunks and the attribute chunk (as was the case before the {extra,...} option was added).
2017-05-04Update copyright yearRaimo Niskanen
2017-04-26Merge pull request #1367 from josevalim/jv-dbgi-chunkBjörn Gustavsson
Introduce new "Dbgi" chunk OTP-14369
2017-04-25Merge branch 'lukas/erts/list_to_port/OTP-14348'Lukas Larsson
* lukas/erts/list_to_port/OTP-14348: erts: Add erlang:list_to_port/1 debug bif erts: Auto-import port_to_list for consistency erts: Polish off erlang:list_to_ref/1
2017-04-25erts: Add erlang:list_to_port/1 debug bifLukas Larsson
2017-04-25erts: Auto-import port_to_list for consistencyLukas Larsson
Follow the same pattern as pid_to_list
2017-04-25warnings_as_errors and outdir do not affect code generationJosé Valim
By moving to effects_code_generation/1, there is no need to explicitly remove those options when storing compile information in the DebugInfo chunk.
2017-04-25Store abstract code in the Dbgi chunkJosé Valim
The new Dbgi chunk returns data in the following format: {debug_info_v1, Backend, Data} This allows compilers to store the debug info in different formats. In order to retrieve a particular format, for instance, Erlang Abstract Format, one may invoke: Backend:debug_info(erlang_v1, Module, Data, Opts) Besides introducing the chunk above, this commit also: * Changes beam_lib:chunk(Beam, [:abstract_code]) to read from the new Dbgi chunk while keeping backwards compatibility with old .beams * Adds the {debug_info, {Backend, Data}} option to compile:file/2 and friends that are stored in the Dbgi chunk. This allows the debug info encryption mechanism to work across compilers * Improves dialyzer to work directly on Core Erlang, allowing languages that do not have the Erlang Abstract Format to be dialyzer as long as they emit the new chunk and their backend implementation is available Backwards compatibility is kept across the board except for those calling beam_lib:chunk(Beam, ["Abst"]), as the old chunk is no longer available. Note however the "Abst" chunk has always been optional. Future OTP versions may remove parsing the "Abst" chunk altogether from beam_lib once Erlang 19 and earlier is no longer supported. The current Dialyzer implementation still supports earlier .beam files and such may also be removed in future versions.
2017-04-22Make beam_validator track type formation for binary operationsMichal Muskala
Fixes https://bugs.erlang.org/browse/ERL-406 - a bug introduced in 0377592dc2238f561291be854d2ce859dd9a5fb1
2017-04-21erts: Polish off erlang:list_to_ref/1Lukas Larsson
2017-04-20compile: Remove the r12 through r15 optionsBjörn Gustavsson
The main purpose of these options is compatibility with old Erlang systems. Since it is no longer possible to communicate with R15B or earlier, we no longer need the r12 through r15 options.
2017-04-19Enhance type-driven optimisation in beam_type.erlMichal Muskala
* kill type information only for affected registers in get_map_elements * bs_get_utf* will produce integers of unicode range This optimises code created by Elixir compiler, where: <<x::utf8,_::binary>> when x in 1..10 will compile the guard to is_integer(X) andalso X >= 1 andalso X =< 10 This allows us to eliminate the is_integer check. * bs_get_float will produce a float * allow to carry type information over other bs instructions killing only the affected registers * kill only x registers after call_fun and apply instructions
2017-04-12Atoms in Core Erlang must be encoded in UTF-8Björn Gustavsson
core_scan will now support and require atoms encoded in UTF-8.
2017-03-24compiler: Add is_tagged_tuple instructionBjörn-Egil Dahlberg
Rewrite the instruction stream on tagged tuple tests. Tagged tuples means a tuple of any arity with an atom as its first element. Typically records, ok-tuples and error-tuples. from: ... {test,is_tuple,Fail,[Src]}. {test,test_arity,Fail,[Src,Sz]}. ... {get_tuple_element,Src,0,Dst}. ... {test,is_eq_exact,Fail,[Dst,Atom]}. ... to: ... {test,is_tagged_tuple,Fail,[Src,Sz,Atom]}. ...
2017-03-13beam_type: Avoid an internal consistency check failureBjörn Gustavsson
Code such as the following: -record(x, {a}). f(R, N0) -> N = N0 / 100, if element(1, R#x.a) =:= 0 -> N end. would fail to compile with the following message: m: function f/2+19: Internal consistency check failed - please report this bug. Instruction: {fmove,{fr,0},{x,1}} Error: {uninitialized_reg,{fr,0}}: This bug was introduced in 348b5e6bee2f. Basically, the beam_type pass placed the fmove instruction in the wrong place. Instructions that store to floating point registers and instructions that read from floating point registers are supposed to be in the same basic block. Fix the problem by flushing all floating points instruction before a call the pseudo-BIF is_record/3, thus making sure that the fmove instruction is placed in the correct block. Here is an annotated listing of the relevant part of the .S file (before the fix): {test_heap,{alloc,[{words,0},{floats,1}]},2}. {fconv,{x,1},{fr,0}}. {fmove,{float,100.0},{fr,1}}. fclearerror. {bif,fdiv,{f,0},[{fr,0},{fr,1}],{fr,0}}. {fcheckerror,{f,0}}. %% The instruction {fmove,{fr,0},{x,1}} should have %% been here. %% Block of instructions expanded from a call to %% the pseudo-BIF is_record/3. (Expanded in a later %% compiler pass.) {test,is_tuple,{f,3},[{x,0}]}. {test,test_arity,{f,3},[{x,0},2]}. {get_tuple_element,{x,0},0,{x,2}}. {test,is_eq_exact,{f,3},[{x,2},{atom,x}]}. {move,{atom,true},{x,2}}. {jump,{f,4}}. {label,3}. {move,{atom,false},{x,2}}. {label,4}. %% End of expansion. %% The fmove instruction that beam_validator complains %% about. {fmove,{fr,0},{x,1}}. Reported-by: Richard Carlsson
2017-02-27v3_core: Combine binary strings to larger integersBjörn Gustavsson
Binary construction that mixes long literal strings with variables will make Dialyzer slow. Example: <<"long string (thousand of characters)",T/binary>> The string literals in binary construction is translated to one binary segment per character; all those segments will slow down Dialyzer. We can speed up Dialyzer if we combine several characters (up to 256) to a signle segment in the binary. It will also slightly speed up the compiler. This optimization will make core listings file with binary strings harder to read, but they were not that easy to read before this change. ERL-308
2017-02-12Add extra_chunks option to compileJosé Valim
This allow languages such as Elixir and LFE to attach extra chunks to the .beam file without having to parse the beam file after compilation. This commit also cleans up the interface to beam_asm, allowing chunks to be passed from the compiler without a need to change beam_asm API on every new chunk.