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diff --git a/lib/compiler/doc/src/notes.xml b/lib/compiler/doc/src/notes.xml index bc1f68337b..d45dfef8f3 100644 --- a/lib/compiler/doc/src/notes.xml +++ b/lib/compiler/doc/src/notes.xml @@ -4,7 +4,7 @@ <chapter> <header> <copyright> - <year>2004</year><year>2017</year> + <year>2004</year><year>2018</year> <holder>Ericsson AB. All Rights Reserved.</holder> </copyright> <legalnotice> @@ -32,6 +32,528 @@ <p>This document describes the changes made to the Compiler application.</p> +<section><title>Compiler 7.3.2</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p>An expression such as <c>(A / B) band 16#ff</c> would + crash the compiler.</p> + <p> + Own Id: OTP-15518 Aux Id: ERL-829 </p> + </item> + <item> + <p>There could be an incorrect warning when the + <c>tuple_calls</c> option was given. The generated code + would be correct. Here is an example of code that would + trigger the warning:</p> + <p><c>(list_to_atom("prefix_" ++ + atom_to_list(suffix))):doit(X)</c>.</p> + <p> + Own Id: OTP-15552 Aux Id: ERL-838 </p> + </item> + <item> + <p>Optimize (again) Dialyzer's handling of + left-associative use of <c>andalso</c> and <c>orelse</c> + in guards.</p> + <p> + Own Id: OTP-15577 Aux Id: ERL-851, PR-2141, PR-1944 </p> + </item> + </list> + </section> + +</section> + +<section><title>Compiler 7.3.1</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p>An optimization that avoided allocation of a stack + frame for some <c>case</c> expressions was introduced in + OTP 21. (ERL-504/OTP-14808) It turns out that in rare + circumstances, this optimization is not safe. Therefore, + this optimization has been disabled.</p> + <p>A similar optimization will be included in OTP 22 in a + safe way.</p> + <p> + Own Id: OTP-15501 Aux Id: ERL-807, ERL-514, OTP-14808 </p> + </item> + </list> + </section> + +</section> + +<section><title>Compiler 7.3</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p>Fixed a rare internal consistency failure caused by a + bug in the <c>beam_jump</c> pass. (Thanks to Simon + Cornish for reporting this bug.)</p> + <p> + Own Id: OTP-15400 Aux Id: ERL-759 </p> + </item> + <item> + <p>The compiler could fail with an internal consistency + check failure when compiling code that used the + <c>is_function/2</c> BIF.</p> + <p> + Own Id: OTP-15435 Aux Id: ERL-778 </p> + </item> + <item> + <p>When an external fun was used, warnings for unused + variables could be suppressed.</p> + <p> + Own Id: OTP-15437 Aux Id: ERL-762 </p> + </item> + <item> + <p>The compiler would crash when compiling an + <c>after</c> block that called <c>erlang:raise/3</c> like + this: <c>erlang:raise(Class, Stacktrace, + Stacktrace)</c></p> + <p> + Own Id: OTP-15481</p> + </item> + </list> + </section> + + + <section><title>Improvements and New Features</title> + <list> + <item> + <p>When specified, the <c>+{source,Name}</c> option will + now override the actual file name in stack traces, + instead of only affecting the return value of + <c>Mod:module_info()</c>.</p> + <p>The <c>+deterministic</c> flag will also affect stack + traces now, omitting all path information except the file + name, fixing a long-standing issue where deterministic + builds required deterministic paths.</p> + <p> + Own Id: OTP-15245 Aux Id: ERL-706 </p> + </item> + </list> + </section> + +</section> + +<section><title>Compiler 7.2.7</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p>Fixed a bug where incorrect code was generated + following a binary match guard.</p> + <p> + Own Id: OTP-15353 Aux Id: ERL-753 </p> + </item> + </list> + </section> + +</section> + +<section><title>Compiler 7.2.6</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p>In rare circumstances, the matched out tail of a + binary could be the entire original binary. (There was + partial correction to this problem in version 7.2.5 of + the compiler application.)</p> + <p> + Own Id: OTP-15335 Aux Id: ERL-689, OTP-15219 </p> + </item> + </list> + </section> + +</section> + +<section><title>Compiler 7.2.5</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p>Fixed a bug that prevented certain variable-sized + binary comprehensions from compiling.</p> + <p> + Own Id: OTP-15186 Aux Id: ERL-665 </p> + </item> + <item> + <p>When compiling from Core Erlang, funs created in + certain expressions that were only used for their + side-effects were subtly broken.</p> + <p> + Own Id: OTP-15188 Aux Id: ERL-658 </p> + </item> + <item> + <p>There could be an internal consistency failure when a + <c>receive</c> was nested in a + <c>try</c>/<c>catch</c>.</p> + <p> + Own Id: OTP-15218 Aux Id: ERL-684 </p> + </item> + <item> + <p>In rare circumstances, the matched out tail of a + binary could be the entire original binary.</p> + <p> + Own Id: OTP-15219 Aux Id: ERL-689 </p> + </item> + <item> + <p>When <c>is_map_key/2</c> was used in a guard together + with the <c>not/1</c> or <c>or/2</c> operators, the error + behavior could be wrong when <c>is_map_key/2</c> was + passed a non-map as the second argument. </p> + <p>In rare circumstances, compiling code that uses + <c>is_map_key/2</c> could cause an internal consistency + check failure.</p> + <p> + Own Id: OTP-15227 Aux Id: ERL-699 </p> + </item> + <item> + <p>The compiler could crash when compiling a function + with multiple receives in multiple clauses.</p> + <p> + Own Id: OTP-15235 Aux Id: ERL-703 </p> + </item> + </list> + </section> + +</section> + +<section><title>Compiler 7.2.4</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p>Fix a regression in OTP-15204 that removed + <c>.beam</c> file metadata that some external build tools + relied on.</p> + <p> + Own Id: OTP-15292</p> + </item> + </list> + </section> + +</section> + +<section><title>Compiler 7.2.3</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p>Fixed an issue where files compiled with the + <c>+deterministic</c> option differed if they were + compiled in a different directory but were otherwise + identical.</p> + <p> + Own Id: OTP-15204 Aux Id: ERL-679 </p> + </item> + </list> + </section> + +</section> + +<section><title>Compiler 7.2.2</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p>In rare cases involving matching of binary literal + strings, the compiler could optimize away code that + should be executed.</p> + <p> + Own Id: OTP-15156 Aux Id: ERL-655 </p> + </item> + <item> + <p>There could be an internal consistency check failure + when compiling code that called <c>map_get(Key, Map)</c> + and then updated the same map.</p> + <p> + Own Id: OTP-15157</p> + </item> + <item> + <p>In rare circumstances, the compiler could crash in + <c>beam_jump</c> when compiling a floating point + operation.</p> + <p> + Own Id: OTP-15166 Aux Id: ERL-660 </p> + </item> + </list> + </section> + +</section> + +<section><title>Compiler 7.2.1</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p>The could could crash when compiling a complicated + function that used the binary syntax.</p> + <p> + Own Id: OTP-15150 Aux Id: ERL-650 </p> + </item> + </list> + </section> + +</section> + +<section><title>Compiler 7.2</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p>Fixed an error in an optimization pass that caused + impossible tuple matching.</p> + <p> + Own Id: OTP-14855 Aux Id: ERL-549 </p> + </item> + <item> + <p>The exception thrown when a list comprehension was + given a non-list term was not always correct.</p> + <p> + Own Id: OTP-14992 Aux Id: ERL-572 </p> + </item> + <item> + <p>The compiler could produce incorrect code in rare + circumstances when the <c>[{inline,F/A}]</c> option was + used.</p> + <p> + Own Id: OTP-15115 Aux Id: PR-1831 </p> + </item> + </list> + </section> + + + <section><title>Improvements and New Features</title> + <list> + <item> + <p>Changed the default behaviour of <c>.erlang</c> + loading: <c>.erlang</c> is no longer loaded from the + current directory. <c>c:erlangrc(PathList)</c> can be + used to search and load an <c>.erlang</c> file from user + specified directories.</p> <p><c>escript</c>, + <c>erlc</c>, <c>dialyzer</c> and <c>typer</c> no longer + load an <c>.erlang</c> at all.</p> + <p> + *** POTENTIAL INCOMPATIBILITY ***</p> + <p> + Own Id: OTP-14439</p> + </item> + <item> + <p>Support for "tuple calls" have been removed from the + run-time system. Tuple calls was an undocumented and + unsupported feature which allowed the module argument for + an apply operation to be a tuple: <c>Var = dict:new(), + Var:size()</c>. This "feature" frequently caused + confusion, especially when such call failed. The + stacktrace would point out functions that don't exist in + the source code.</p> + <p>For legacy code that need to use parameterized modules + or tuple calls for some other reason, there is a new + compiler option called <c>tuple_calls</c>. When this + option is given, the compiler will generate extra code + that emulates the old behavior for calls where the module + is a variable.</p> + <p> + *** POTENTIAL INCOMPATIBILITY ***</p> + <p> + Own Id: OTP-14497</p> + </item> + <item> + <p>In code such as <c>example({ok, Val}) -> {ok, + Val}.</c> a tuple would be built. The compiler will now + automatically rewrite the code to + <c>example({ok,Val}=Tuple) -> Tuple.</c> which will + reduce code size, execution time, and remove GC + pressure.</p> + <p> + Own Id: OTP-14505</p> + </item> + <item> + <p>The optimization of <c>case</c> expression where only + one of the case arms can execute successfully has been + improved.</p> + <p> + Own Id: OTP-14525</p> + </item> + <item> + <p>Some uses of binary matching has been slightly + improved, eliminating unnecessary register shuffling.</p> + <p> + Own Id: OTP-14594 Aux Id: ERL-444 </p> + </item> + <item> + <p>There is a new <c>{compile_info,Info}</c> option for + the compiler that allows BEAM-based languages such as + Elixir and LFE to add their own compiler versions.</p> + <p> + Own Id: OTP-14615 Aux Id: PR-1558 </p> + </item> + <item> + <p>Loaded BEAM code in a 64-bit system requires less + memory because of better packing of operands for + instructions.</p> + <p>These memory savings were achieved by major + improvements to the <c>beam_makeops</c> scripts used when + building the run time system and BEAM compiler. There is + also new for documentation for <c>beam_makeops</c> that + describes how new BEAM instructions and loader + transformations can be implemented. The documentation is + found in here in a source directory or git repository: + erts/emulator/internal_doc/beam_makeops.md. An online + version can be found here: + https://github.com/erlang/otp/blob/master/erts/emulator/internal_doc/beam_makeops.md</p> + <p> + Own Id: OTP-14626</p> + </item> + <item> + <p>Size calculations for binary constructions has been + somewhat optimized, producing smaller code.</p> + <p> + Own Id: OTP-14654</p> + </item> + <item> + <p>When the value returned from a '<c>catch</c>' + expression is ignored, no stacktrace will be built if an + exception is caught. That will save time and produce less + garbage. There are also some minor optimizations of + '<c>try</c>/<c>catch</c>' both in the compiler and + run-time system.</p> + <p> + Own Id: OTP-14683</p> + </item> + <item> + <p>There is a new syntax in '<c>try/catch</c>' for + retrieving the stacktrace without calling + '<c>erlang:get_stacktrace/0</c>'. See the reference + manual for a description of the new syntax. The + '<c>erlang:get_stacktrace/0</c>' BIF is now + deprecated.</p> + <p> + Own Id: OTP-14692</p> + </item> + <item> + <p>The following is an internal change in the compiler, + that is not noticeable for normal use of the compiler: + The module <c>v3_life</c> has been removed. Its + functionality has been simplified and integrated into + <c>v3_codegen</c>.</p> + <p> + Own Id: OTP-14712</p> + </item> + <item> + <p>The optimization of binary matching that delays + creation of sub binaries (see the Efficiency Guide) could + be thwarted by the argument order and could be necessary + to change the argument order. The compiler has now become + smarter and can handle any argument order.</p> + <p> + Own Id: OTP-14774</p> + </item> + <item> + <p>When the compiler was faced with complex case + expressions it would unnecessarily allocate stack + elements and shuffle data between x and y registers. + Improved code generation to only allocate a stack frame + when strictly necessary.</p> + <p> + Own Id: OTP-14808 Aux Id: ERL-514 </p> + </item> + <item> + <p>There is a new option '<c>makedep_side_effect</c>' for + the compiler and <c>-MMD</c> for '<c>erlc</c>' that + generates dependencies and continues to compile as + normal.</p> + <p> + Own Id: OTP-14830</p> + </item> + <item> + <p>When compiling modules with huge functions, the + compiler would generate a lot of atoms for its internal, + sometimes so many that the atom table would overflow. The + compiler has been rewritten to generate far less internal + atoms to avoid filling the atom table.</p> + <p> + Own Id: OTP-14968 Aux Id: ERL-563 </p> + </item> + <item> + <p>External funs with literal values for module, name, + and arity (e.g. <c>erlang:abs/1</c>) are now treated as + literals. That means more efficient code that produces + less garbage on the heap.</p> + <p> + Own Id: OTP-15003</p> + </item> + <item> + <p>Two new guards BIFs operating on maps have been added: + <c>map_get/2</c> and <c>is_map_key/2</c>. They do the + same as <c>maps:get/2</c> and <c>maps:is_key/2</c>, + respectively, except that they are allowed to be used in + guards.</p> + <p> + Own Id: OTP-15037 Aux Id: PR-1784, PR-1802 </p> + </item> + <item> + <p>A call or apply of a literal external fun will be + replaced with a direct call.</p> + <p> + Own Id: OTP-15044 Aux Id: ERL-614 </p> + </item> + <item> + <p>Part of EEP-44 has been implemented.</p> + <p>There is a new predefined macro called + <c>OTP_RELEASE</c> which is an integer indicating the OTP + release number (its value is <c>21</c> in this + release).</p> + <p>There are new preprocessor directives + <c>-if(Condition).</c> and <c>-elif(Condition).</c>. The + <c>if/elif</c> supports the builtin function + <c>defined(Symbol)</c>.</p> + <p> + Own Id: OTP-15087 Aux Id: PR-1810 </p> + </item> + </list> + </section> + +</section> + +<section><title>Compiler 7.1.5.2</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p>Fix a regression in OTP-15204 that removed + <c>.beam</c> file metadata that some external build tools + relied on.</p> + <p> + Own Id: OTP-15292</p> + </item> + </list> + </section> + +</section> + +<section><title>Compiler 7.1.5.1</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p>Fixed an issue where files compiled with the + <c>+deterministic</c> option differed if they were + compiled in a different directory but were otherwise + identical.</p> + <p> + Own Id: OTP-15204 Aux Id: ERL-679 </p> + </item> + </list> + </section> + +</section> + <section><title>Compiler 7.1.5</title> <section><title>Fixed Bugs and Malfunctions</title> |