diff options
Diffstat (limited to 'lib/compiler/doc/src')
| -rw-r--r-- | lib/compiler/doc/src/Makefile | 14 | ||||
| -rw-r--r-- | lib/compiler/doc/src/book.xml | 3 | ||||
| -rw-r--r-- | lib/compiler/doc/src/compile.xml | 99 | ||||
| -rw-r--r-- | lib/compiler/doc/src/internal.xml | 38 | ||||
| -rw-r--r-- | lib/compiler/doc/src/notes.xml | 617 |
5 files changed, 739 insertions, 32 deletions
diff --git a/lib/compiler/doc/src/Makefile b/lib/compiler/doc/src/Makefile index 13210de040..2fb163b9e7 100644 --- a/lib/compiler/doc/src/Makefile +++ b/lib/compiler/doc/src/Makefile @@ -1,7 +1,7 @@ # # %CopyrightBegin% # -# Copyright Ericsson AB 1997-2017. All Rights Reserved. +# Copyright Ericsson AB 1997-2018. 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. @@ -31,6 +31,7 @@ APPLICATION=compiler # Release directory specification # ---------------------------------------------------- RELSYSDIR = $(RELEASE_PATH)/lib/$(APPLICATION)-$(VSN) +COMPILER_DIR = $(ERL_TOP)/lib/compiler/src # ---------------------------------------------------- # Target Specs @@ -38,7 +39,7 @@ RELSYSDIR = $(RELEASE_PATH)/lib/$(APPLICATION)-$(VSN) XML_APPLICATION_FILES = ref_man.xml XML_REF3_FILES = compile.xml -XML_PART_FILES = +XML_PART_FILES = internal.xml XML_CHAPTER_FILES = notes.xml BOOK_FILES = book.xml @@ -49,6 +50,9 @@ XML_FILES = \ $(BOOK_FILES) $(XML_CHAPTER_FILES) \ $(XML_PART_FILES) $(XML_REF3_FILES) $(XML_APPLICATION_FILES) +XML_INTERNAL_FILES = \ + cerl.xml cerl_trees.xml cerl_clauses.xml + # ---------------------------------------------------- HTML_FILES = $(XML_APPLICATION_FILES:%.xml=$(HTMLDIR)/%.html) \ @@ -62,6 +66,8 @@ HTML_REF_MAN_FILE = $(HTMLDIR)/index.html TOP_PDF_FILE = $(PDFDIR)/$(APPLICATION)-$(VSN).pdf +XML_GEN_FILES = $(XML_INTERNAL_FILES:%=$(XMLDIR)/%) + # ---------------------------------------------------- # FLAGS # ---------------------------------------------------- @@ -85,10 +91,14 @@ man: $(MAN3_FILES) gifs: $(GIF_FILES:%=$(HTMLDIR)/%) +$(XML_INTERNAL_FILES:%=$(XMLDIR)/%): $(COMPILER_DIR)/$(@:$(XMLDIR)/%.xml=%.erl) + $(gen_verbose)escript $(DOCGEN)/priv/bin/xml_from_edoc.escript -def vsn $(COMPILER_VSN) -dir $(XMLDIR) $(COMPILER_DIR)/$(@:$(XMLDIR)/%.xml=%.erl) + debug opt: clean clean_docs: rm -rf $(HTMLDIR)/* + rm -rf $(XMLDIR) rm -f $(MAN3DIR)/* rm -f $(TOP_PDF_FILE) $(TOP_PDF_FILE:%.pdf=%.fo) rm -f errs core *~ diff --git a/lib/compiler/doc/src/book.xml b/lib/compiler/doc/src/book.xml index af6b4cf47a..d101d40cb4 100644 --- a/lib/compiler/doc/src/book.xml +++ b/lib/compiler/doc/src/book.xml @@ -38,6 +38,9 @@ <applications> <xi:include href="ref_man.xml"/> </applications> + <internals> + <xi:include href="internal.xml"/> + </internals> <releasenotes> <xi:include href="notes.xml"/> </releasenotes> diff --git a/lib/compiler/doc/src/compile.xml b/lib/compiler/doc/src/compile.xml index 10164890f2..549b1049d8 100644 --- a/lib/compiler/doc/src/compile.xml +++ b/lib/compiler/doc/src/compile.xml @@ -4,7 +4,7 @@ <erlref> <header> <copyright> - <year>1996</year><year>2017</year> + <year>1996</year><year>2018</year> <holder>Ericsson AB. All Rights Reserved.</holder> </copyright> <legalnotice> @@ -29,7 +29,7 @@ <rev>A</rev> <file>compile.sgml</file> </header> - <module>compile</module> + <module since="">compile</module> <modulesummary>Erlang Compiler</modulesummary> <description> <p>This module provides an interface to the standard Erlang @@ -40,7 +40,7 @@ <funcs> <func> - <name>env_compiler_options()</name> + <name since="OTP 19.0">env_compiler_options()</name> <fsummary> Compiler options defined via the environment variable <c>ERL_COMPILER_OPTIONS</c> @@ -53,7 +53,7 @@ </desc> </func> <func> - <name>file(File)</name> + <name since="">file(File)</name> <fsummary>Compiles a file.</fsummary> <desc> <p>Is the same as @@ -63,7 +63,7 @@ </func> <func> - <name>file(File, Options) -> CompRet</name> + <name since="">file(File, Options) -> CompRet</name> <fsummary>Compiles a file.</fsummary> <type> <v>CompRet = ModRet | BinRet | ErrRet</v> @@ -123,6 +123,17 @@ in the Efficiency Guide.</p> </item> + <tag><c>{compile_info, [{atom(), term()}]}</c></tag> + <item> + <p>Allows compilers built on top of <c>compile</c> to attach + extra compilation metadata to the <c>compile_info</c> chunk + in the generated beam file.</p> + + <p>It is advised for compilers to remove all non-deterministic + information if the <c>deterministic</c> option is supported and + it was supplied by the user.</p> + </item> + <tag><c>compressed</c></tag> <item> <p>The compiler will compress the generated object code, @@ -192,7 +203,8 @@ <tag><c>deterministic</c></tag> <item> <p>Omit the <c>options</c> and <c>source</c> tuples in - the list returned by <c>Module:module_info(compile)</c>. + the list returned by <c>Module:module_info(compile)</c>, and + reduce the paths in stack traces to the module name alone. This option will make it easier to achieve reproducible builds. </p> </item> @@ -222,6 +234,15 @@ module.beam: module.erl \ header.hrl</code> </item> + <tag><c>makedep_side_effect</c></tag> + <item> + <p>The dependecies are created as a side effect to the + normal compilation process. This means that the object + file will also be produced. This option override the + <c>makedep</c> option. + </p> + </item> + <tag><c>{makedep_output, Output}</c></tag> <item> <p>Writes generated rules to <c>Output</c> instead of the @@ -327,8 +348,8 @@ module.beam: module.erl \ <tag><c>{source,FileName}</c></tag> <item> - <p>Sets the value of the source, as returned by - <c>module_info(compile)</c>.</p> + <p>Overrides the source file name as presented in + <c>module_info(compile)</c> and stack traces.</p> </item> <tag><c>{outdir,Dir}</c></tag> @@ -395,6 +416,17 @@ module.beam: module.erl \ is not documented, and can change between releases.</p> </item> + <tag><c>no_spawn_compiler_process</c></tag> + <item> + <p>By default, all code is compiled in a separate process + which is terminated at the end of compilation. However, + some tools, like Dialyzer or compilers for other BEAM languages, + may already manage their own worker processes and spawning + an extra process may slow the compilation down. + In such scenarios, you can pass this option to stop the + compiler from spawning an additional process.</p> + </item> + <tag><c>no_strict_record_tests</c></tag> <item> <p>This option is not recommended.</p> @@ -600,6 +632,22 @@ module.beam: module.erl \ to be deprecated.</p> </item> + <tag><c>nowarn_removed</c></tag> + <item> + <p>Turns off warnings for calls to functions that have + been removed. Default is to emit warnings for every call + to a function known by the compiler to have been recently + removed from Erlang/OTP.</p> + </item> + + <tag><c>{nowarn_removed, ModulesOrMFAs}</c></tag> + <item> + <p>Turns off warnings for calls to modules or functions + that have been removed. Default is to emit warnings for + every call to a function known by the compiler to have + been recently removed from Erlang/OTP.</p> + </item> + <tag><c>nowarn_obsolete_guard</c></tag> <item> <p>Turns off warnings for calls to old type testing BIFs, @@ -629,14 +677,6 @@ module.beam: module.erl \ <p>Turns off warnings for unused record types. Default is to emit warnings for unused locally defined record types.</p> </item> - - <tag><c>nowarn_get_stacktrace</c></tag> - <item> - <p>Turns off warnings for using <c>get_stacktrace/0</c> in a context - where it will probably not work in a future release. For example, - by default there will be a warning if <c>get_stacktrace/0</c> is - used following a <c>catch</c> expression.</p> - </item> </taglist> <p>Another class of warnings is generated by the compiler @@ -671,12 +711,13 @@ module.beam: module.erl \ </note> <note> - <p>The options <c>{nowarn_unused_function, FAs}</c>, - <c>{nowarn_bif_clash, FAs}</c>, and - <c>{nowarn_deprecated_function, MFAs}</c> are only - recognized when given in files. They are not affected by - options <c>warn_unused_function</c>, <c>warn_bif_clash</c>, or - <c>warn_deprecated_function</c>.</p> + <p>Before OTP 22, the option <c>{nowarn_deprecated_function, + MFAs}</c> was only recognized when given in the file with + attribute <c>-compile()</c>. (The option + <c>{nowarn_unused_function,FAs}</c> was incorrectly documented + to only work in a file, but it also worked when given in the + option list.) Starting from OTP 22, all options that can be + given in the file can also be given in the option list.</p> </note> <p>For debugging of the compiler, or for pure curiosity, @@ -705,7 +746,7 @@ module.beam: module.erl \ </func> <func> - <name>forms(Forms)</name> + <name since="">forms(Forms)</name> <fsummary>Compiles a list of forms.</fsummary> <desc> <p>Is the same as @@ -715,7 +756,7 @@ module.beam: module.erl \ </func> <func> - <name>forms(Forms, Options) -> CompRet</name> + <name since="">forms(Forms, Options) -> CompRet</name> <fsummary>Compiles a list of forms.</fsummary> <type> <v>Forms = [Form]</v> @@ -736,7 +777,7 @@ module.beam: module.erl \ </func> <func> - <name>format_error(ErrorDescriptor) -> chars()</name> + <name since="">format_error(ErrorDescriptor) -> chars()</name> <fsummary>Formats an error descriptor.</fsummary> <type> <v>ErrorDescriptor = errordesc()</v> @@ -751,7 +792,7 @@ module.beam: module.erl \ </func> <func> - <name>output_generated(Options) -> true | false</name> + <name since="">output_generated(Options) -> true | false</name> <fsummary>Determines whether the compiler generates an output file.</fsummary> <type> <v>Options = [term()]</v> @@ -766,7 +807,7 @@ module.beam: module.erl \ </func> <func> - <name>noenv_file(File, Options) -> CompRet</name> + <name since="">noenv_file(File, Options) -> CompRet</name> <fsummary>Compiles a file (ignoring <c>ERL_COMPILER_OPTIONS)</c>.</fsummary> <desc> <p>Works like <seealso marker="#file/2">file/2</seealso>, @@ -776,7 +817,7 @@ module.beam: module.erl \ </func> <func> - <name>noenv_forms(Forms, Options) -> CompRet</name> + <name since="">noenv_forms(Forms, Options) -> CompRet</name> <fsummary>Compiles a list of forms (ignoring <c>ERL_COMPILER_OPTIONS)</c>.</fsummary> <desc> <p>Works like <seealso marker="#forms/2">forms/2</seealso>, @@ -786,7 +827,7 @@ module.beam: module.erl \ </func> <func> - <name>noenv_output_generated(Options) -> true | false</name> + <name since="">noenv_output_generated(Options) -> true | false</name> <fsummary>Determines whether the compiler generates an output file (ignoring <c>ERL_COMPILER_OPTIONS)</c>.</fsummary> <type> diff --git a/lib/compiler/doc/src/internal.xml b/lib/compiler/doc/src/internal.xml new file mode 100644 index 0000000000..f24b363c1c --- /dev/null +++ b/lib/compiler/doc/src/internal.xml @@ -0,0 +1,38 @@ +<?xml version="1.0" encoding="utf-8" ?> +<!DOCTYPE part SYSTEM "part.dtd"> + +<internal xmlns:xi="http://www.w3.org/2001/XInclude"> + <header> + <copyright> + <year>2018</year><year>2018</year> + <holder>Ericsson AB. All Rights Reserved.</holder> + </copyright> + <legalnotice> + 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. + + </legalnotice> + + <title>Compiler Internal Documentation</title> + <prepared>Lukas Larsson</prepared> + <docno></docno> + <date>2018-07-07</date> + <rev>1.0.0</rev> + <file>internal.xml</file> + </header> + <description> + </description> + <xi:include href="cerl.xml"/> + <xi:include href="cerl_trees.xml"/> + <xi:include href="cerl_clauses.xml"/> +</internal> + diff --git a/lib/compiler/doc/src/notes.xml b/lib/compiler/doc/src/notes.xml index bc1f68337b..275c6268fa 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 +32,621 @@ <p>This document describes the changes made to the Compiler application.</p> +<section><title>Compiler 7.4</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p><c>record_info/2</c> is a pseudo-function that + requires literal arguments known at compile time. + Therefore, the following usage is illegal: <c>fun + record/info/2</c>. The compiler would crash when during + compilation of that kind of code. Corrected to issue a + compilation error.</p> + <p> + Own Id: OTP-15760 Aux Id: ERL-907 </p> + </item> + </list> + </section> + + + <section><title>Improvements and New Features</title> + <list> + <item> + <p> + The compiler has been rewritten to internally use an + intermediate representation based on Static Single + Assignment (SSA). The new intermediate representation + makes more optimizations possible.</p> + <p> + Most noticeable is that the binary matching optimizations + are now applicable in many more circumstances than + before.</p> + <p> + Another noticeable change is that type optimizations are + now applied across local function calls, and will remove + a lot more redundant type tests than before.</p> + <p> + Own Id: OTP-14894 Aux Id: ERL-714 </p> + </item> + <item> + <p>Funs are no longer created when they are only used + locally, greatly improving the performance of named funs + and "fun-wrapped" macros.</p> + <p> + Own Id: OTP-15273 Aux Id: ERL-639 </p> + </item> + <item> + <p>All compiler options that can be given in the source + file can now also be given in the option list or from the + command line for <c>erlc</c>.</p> + <p>Specifically, the option + <c>{nowarn_deprecated_function,MFAs}</c> was only + recognized when given in the file with the attribute + <c>-compile()</c>. The option + <c>{nowarn_unused_function,FAs}</c> was incorrectly + documented to only work in a file, but it also worked + when given in the option list.</p> + <p> + Own Id: OTP-15456</p> + </item> + <item> + <p> Do not allow function specifications for functions + residing in other modules. </p> + <p> + *** POTENTIAL INCOMPATIBILITY ***</p> + <p> + Own Id: OTP-15563 Aux Id: ERL-845, OTP-15562 </p> + </item> + <item> + <p>Internal documentation has now been added to the + <em>Erts</em> and <em>Compiler</em> applications.</p> + <p>The internal documents for <em>Erts</em> describe + miscellaneous interesting implementation details. Those + details can change at any time.</p> + <p>The internal documentation for <em>Compiler</em> + documents the API for the Core Erlang modules. While we + will not change those APIs without good reason, we don't + give the same guarantees about backward compatibility as + for the rest of the APIs in OTP.</p> + <p> + Own Id: OTP-15715</p> + </item> + <item> + <p> There are new compiler options <c>nowarn_removed</c> + and <c>{nowarn_removed,Items}</c> to suppress warnings + for functions and modules that have been removed from + OTP.</p> + <p> + Own Id: OTP-15749 Aux Id: ERL-904 </p> + </item> + </list> + </section> + +</section> + +<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> |