diff options
Diffstat (limited to 'NEWS')
| -rw-r--r-- | NEWS | 340 |
1 files changed, 338 insertions, 2 deletions
@@ -1,6 +1,317 @@ Version 0.14.0 - * Allow unseparated scope-qualified variable assignment and expansion. + * Support for hermetic build configurations. + + Hermetic build configurations save environment variables that affect the + project along with other project configuration in the config.build file. + These saved environment variables are then used instead of the current + environment when performing operations on the project, thus making sure + the project "sees" exactly the same environment as during configuration. + The built-in ~host and ~build2 configurations are now hermetic. + + Hermetic configuration support is built on top of the lower-level + config.config.environment configuration variable which allows us to save a + custom set of environment variables/values. + + As part of this work we now also track changes to the environment in non- + hermetic configurations and automatically rebuild affected targets. + + See "Hermetic Build Configurations" in the manual for details. + + * Support for ad hoc regex pattern rules. + + An ad hoc pattern rule consists of a pattern that mimics a dependency + declaration followed by one or more recipes. For example: + + exe{~'/(.*)/'}: cxx{~'/\1/'} + {{ + $cxx.path -o $path($>) $path($<[0]) + }} + + If a pattern matches a dependency declaration of a target, then the recipe + is used to perform the corresponding operation on this target. For + example, the following dependency declaration matches the above pattern + which means the rule's recipe will be used to update this target: + + exe{hello}: cxx{hello} + + While the following declarations do not match the above pattern: + + exe{hello}: c{hello} # Type mismatch. + exe{hello}: cxx{howdy} # Name mismatch. + + On the left hand side of `:` in the pattern we can have a single target or + an ad hoc target group. The single target or the first (primary) ad hoc + group member must be a regex pattern (~). The rest of the ad hoc group + members can be patterns or substitutions (^). For example: + + <exe{~'/(.*)/'} file{^'/\1.map/'}>: cxx{~'/\1/'} + {{ + $cxx.path -o $path($>[0]) "-Wl,-Map=$path($>[1])" $path($<[0]) + }} + + On the right hand side of `:` in the pattern we have prerequisites which + can be patterns, substitutions, or non-patterns. For example: + + <exe{~'/(.*)/'} file{^'/\1.map/'}>: cxx{~'/\1/'} hxx{^'/\1/'} hxx{common} + {{ + $cxx.path -o $path($>[0]) "-Wl,-Map=$path($>[1])" $path($<[0]) + }} + + Substitutions on the left hand side of `:` and substitutions and non- + patterns on the right hand side are added to the dependency declaration. + For example, given the above rule and dependency declaration, the + effective dependency is going to be: + + <exe{hello} file{hello.map>: cxx{hello} hxx{hello} hxx{common} + + Similar to ad hoc recipes, ad hoc rules can be written in Buildscript or + C++. + + * Support for regex patterns in target type/pattern-specific variables. + + This is in addition to the already supported path patterns. For example: + + hxx{*}: x = y # path pattern + hxx{~/.*/}: x = y # regex pattern + + * New pre-defined semantics for the config.<project>.develop variable. + + This variable allows a project to distinguish between development and + consumption builds. While normally there is no distinction, sometimes a + project may need to provide additional functionality during development. + For example, a source code generator which uses its own generated code in + its implementation may need to provide a bootstrap step from the pre- + generated code. Normally, such a step is only needed during development. + + If used, this variable should be explicitly defined by the project with + the bool type and the false default value. For example: + + config [bool] config.hello.develop ?= false + + See "Project Configuration" in the manual for details. + + * Support for warning suppression from external C/C++ libraries. + + This is implemented by defining a notion of a project's internal scope and + automatically translating header search path options (-I) exported by + libraries that are outside of the internal scope to appropriate "external + header search path" options (-isystem for GCC/Clang, /external:I for MSVC + 16.10 and later). In the future this functionality will be extended to + side-building BMIs for external module interfaces and header units. + + Note that this functionality is not without limitations and drawbacks and, + if needed, should be enabled explicitly. See the "C++ Compilation Internal + Scope" section in the manual for details. + + * C++20 modules support in GCC 11 using the module mapper. + + This support covers all the major C++20 modules features including named + modules, module partitions (both interface and implementation), header + unit importation, and include translation. All of these features are also + supported in libraries, including consumption of installed libraries with + information about modules and importable headers conveyed in pkg-config + files. Module interface-only libraries are also supported. + + Note that one area that is not yet well supported (due to module mapper + limitations) is auto-generated headers. Also note that as of version 11, + support for modules in GCC is still experimental and incomplete. + + * Support for automatic DLL symbol exporting. + + The bin.def module (automatically loaded by the c and cxx modules for the + *-win32-msvc targets) provides a rule for generating symbol-exporting .def + files. This allows automatically exporting all symbols for all the Windows + targets/compilers using the following setup (showing for cxx in this + example): + + lib{foo}: libul{foo}: {hxx cxx}{**} ... + + lib{foo}: def{foo}: include = ($cxx.target.system == 'win32-msvc') + def{foo}: libul{foo} + + if ($cxx.target.system == 'mingw32') + cxx.loptions += -Wl,--export-all-symbols + + That is, we use the .def file generation for MSVC (including when building + with Clang) and the built-in support (--export-all-symbols) for MinGW. + + Note that it is also possible to use the .def file generation for MinGW. + In this case we need to explicitly load the bin.def module (which should + be done after loading c or cxx) and can use the following setup: + + using bin.def # In root.build after loading c/cxx. + + lib{foo}: libul{foo}: {hxx cxx}{**} ... + + lib{foo}: def{foo}: include = ($cxx.target.class == 'windows') + def{foo}: libul{foo} + + * Initial Emscripten compiler support. + + - Target: wasm32-emscripten (wasm32-unknown-emscripten). + + - Compiler id: clang-emscripten (type clang, variant emscripten, class + gcc). + + - Ability to build executables (.js plus .wasm) and static libraries (.a). + Set executable bit on the .js file (so it can be executed with a + suitable binfmt interpreter). Track the additional .worker.js file if + -pthread is specified. + + - Default config.bin.lib for wasm32-emscripten is static instead of both. + + - Full C++ exception support is enabled by default unless disabled + explicitly by the user with -s DISABLE_EXCEPTION_CATCHING=1|2. + + - The bin module registers the wasm{} target type for wasm32-emscripten. + + * New string functions: $string.trim(), $string.lcase(), $string.ucase(). + + * Support for test runners (config.test.runner). + Support for test timeouts (config.test.timeout). + + See "test Module" in the manual for details. + + * New <version> install directory substitution in addition to <project>. + New config.install.etc variable with the data_root/etc/ default. + + See the "install Module" chapter in the manual for details. + + * Support for fallback substitution in the in module (in.null variable). + + See "in Module" in the manual for details. + + * New export pseudo-builtin that allows adding/removing variables to/from + the current scope's commands execution environment. + + See the Testscript manual for details. + + * New ad hoc recipe depdb preamble. + + The Buildscript language now provides a new pseudo-builtin, depdb, that + allows tracking of custom auxiliary dependency information. Invocations of + this builtin should come before any recipe commands and are collectively + called the depdb preamble. Non-pure functions can now only be called as + part of this preamble. For example: + + file{output}: file{input} $foo + {{ + diag foo $> + depdb env FOO # foo uses the FOO environment variable + $foo $path($<[0]) >$path($>) + }} + + * New ${c,cxx}.deduplicate_export_libs() functions. + + These functions deduplicate interface library dependencies by removing + libraries that are also interface dependencies of other libraries on the + specified list. This can lead to a significantly better build performance + for heavily interface-interdependent library families (for example, like + Boost). Typical usage: + + import intf_libs = ... + import intf_libs += ... + ... + import intf_libs += ... + intf_libs = $cxx.deduplicate_export_libs($intf_libs) + + * New ${c,cxx}.find_system_{header,library}() functions. + + These functions can be used to detect the presence of a header/library in + one of the system header/library search directories. + + * New ${c,cxx}.lib_{poptions,libs,rpaths}() and $cxx.obj_modules() functions. + + These functions can be used to query library metadata for options and + libraries that should be used when compiling/linking dependent targets, + similar to how cc::{compile,link}_rule do it. With this support it should + be possible to more or less re-create their semantics in ad hoc recipes. + + * Support for suppressing duplicates when extracting library options and + linking libraries in cc::{compile,link}_rule. + + * Support for LTO parallelization during linking in GCC and Clang. + + GCC >= 10 and Clang >= 4 support controlling the number of LTO threads + used during linking. The cc::link_rule now uses the build system scheduler + to automatically allocate up to the number of available threads to the GCC + or Clang linker processes when -flto=auto or -flto=thin is specified, + respectively. + + * /Zc:__cplusplus is now passed by default starting from MSVC 15.7. + + This can be overridden by passing a variant of this option as part of the + compiler mode options. + + * Support for disabling clean through target-prerequisite relationships. + + The current semantics is to clean any prerequisites that are in the same + project (root scope) as the target and it may seem more natural to rather + only clean prerequisites that are in the same base scope. While it's often + true for simple projects, in more complex cases it's not unusual to have + common intermediate build results (object files, utility libraries, etc) + residing in the parent and/or sibling directories. With such arrangements, + cleaning only in base may leave such intermediate build results laying + around since there is no reason to list them as prerequisites of any + directory aliases. + + So we clean in the root scope by default but now any target-prerequisite + relationship can be marked not to trigger a clean with the clean=false + prerequisite-specific value. For example: + + man1{cli}: exe{cli}: clean = false # Don't clean the man generation tool. + + * exe{} targets are no longer installed through target-prerequisite + relationships of file-based targets. + + Normally, an exe{} that is listed as a prerequisite of a file-based target + is there to be executed (for example, to generate that target) and not to + trigger its installation (such an exe{} would typically be installed via + the ./ alias). This default behavior, however, can be overridden with the + install=true prerequisite-specific value. For example: + + exe{foo}: exe{bar}: install = true # foo runs bar + + * Consistently install prerequisites from any scope by default. + + It is also now possible to adjust this behavior with the global + !config.install.scope override. Valid values for this variable are: + + project -- only from project + bundle -- from bundle amalgamation + strong -- from strong amalgamation + weak -- from weak amalgamation + global -- from all projects (default) + + * Variable names/components that start with underscore as well as variables + in the build, import, and export namespaces are now reserved by the build + system core. For example: + + _x = 1 # error + x._y = 1 # error + build.x = 1 # error + + * New int64 (signed 64-bit integer) and int64s (vector of such integers) + variable types. + + * Default options files can now contain global variable overrides. + + * Support for multiple -e options (scripts) in the sed builtin. + + * The bin.lib.version variable no longer needs to include leading `@` for + platform-independent versions. + + * The actualize mode of $path.normalize() is now provided by a separate + $path.actualize() function. + + * New --options-file build system driver option that allows specifying + additional options in a file. + + * New notion of bundle amalgamation which is defined as the outermost named + strong (source-based) amalgamation. + + * Support for unseparated scope-qualified variable assignment and expansion. For example, now the following: @@ -16,6 +327,31 @@ Version 0.14.0 it also means that variable names that contain directory separators are now effectively reserved. + * New bootstrap distribution mode (!config.dist.bootstrap=true). + + In this mode the dist meta-operation does not load the project (but does + bootstrap it) and adds all the source files into the distribution only + ignoring files and directories that start with a dot. This mode is + primarily meant for situations where the project cannot (yet) be loaded + due to missing dependencies. + + * Support for external build system modules that require bootstrap (that is, + loaded in bootstrap.build). See also the new --no-external-modules option. + + * New file cache for intermediate build results. + + The file cache is used to store intermediate build results, for example, + partially-preprocessed C/C++ translation units (those .i/.ii files). The + cache implementation to use is controlled by the new --file-cache option. + Its valid values are noop (no caching or compression) and sync-lz4 (no + caching with synchronous LZ4 on-disk compression; this is the default). + + * New BUILD2_DEF_OPT environment variable that can be used to suppress + loading of default options files. + + * New BUILD2_DEF_OVR environment variable that can be used to propagate + global variable overrides to nested build system invocations. + Version 0.13.0 * Support for project-specific configuration. @@ -203,7 +539,7 @@ Version 0.13.0 $ b config.install.private=foo install - See the "Install Module" chapter in the manual for details. + See the "install Module" chapter in the manual for details. * New $regex.find_{match,search}() functions that operate on lists. |