Release Notes

The dates in the following release notes denote when Chrome and the NaCl SDK reached canary status. The stable release is typically 6 weeks later.

Chrome/Pepper 49

• GCC-based newlib toolchains removed from the SDK. These have been superseded by the nacl-clang toolchain which also produces statically linked architecture specific nexe files.
• gtest/gmock no longer shipped as pre-built libraries. This is in-line with normal gtest/gmock usage guidelines. Projects wishing to use gtest/gmock must now add explicit include paths and compile gtest-all.cc locally.

Chrome/Pepper 45 (10 July 2015)

Pepper

• UDP Socket Multicast API in stable (PPB_UDP_SOCKET 1.2).

Chrome/Pepper 43 (03 April 2015)

PNaCl

• The C11/C++11 acquire, release, and acq_rel memory orders are now generated by default. The in-browser Chrome 42 translator supports them, the SDK can therefore generate them.
• Fix a code generation bug on ARM when dealing with 16-bit load/store and bswap which led to a NaCl validation failure.
• PNaCl is now based on LLVM 3.6. If you are using GDB to debug PNaCl BC files with debug metadata in the browser, remember that debug info from SDK version X is only compatible with the PNaCl translator in chrome version X. The bitcode debug metadata format changed from LLVM 3.5 to 3.6. If you need to debug an app built with SDK version X running in Chrome version Y (with X != Y), it is still possible to do so. Simply translate the pexe to a nexe using the offline pnacl-translate tool from SDK version X instead of using the translator in the browser (version Y).
• PNaCl’s support for use of libstdc++ 4.6 as the C++ standard library is deprecated and will be removed in the next release. PNaCl has used libc++ (which is much more up to date, currently based on LLVM 3.6) as the default since Pepper 33.
• PNaCl’s experimental Subzero translator is available for x86-32 NaCl in Chrome version 43, behind a flag. To give it a try, run Chrome with the --enable-pnacl-subzero commandline flag, and use the optlevel 0 NaCl manifest option. Application startup time should be several times faster than the previous LLVM-based optlevel 0 mode, with similar code quality. Note that x86-32 NaCl requires a 32-bit Chrome. On Windows, it also requires a 32-bit Windows OS, but 64-bit Linux OSes can run x86-32 NaCl. If you try it out, please send us feedback on native-client-dev. We are working on improvements and adding new targets.

Pepper

• UDP Socket Multicast API in development preview (PPB_UDP_SOCKET 1.2).
• Hardware Video Encoder API in development preview (PPB_VIDEO_ENCODER 0.1).

Chrome/Pepper 42 (20 February 2015)

SDK

• The SDK now contains experimental versions of i686-nacl-clang, x86_64-nacl-clang, and arm-nacl-clang as well as the clang++ equivalents. These toolchains are based on the same LLVM version as PNaCl, but can be used to generate NaCl .nexe files instead of translating a .pexe locally or using the GCC toolchain.

NaCl

• The x86 NaCl validators accept instructions from the FMA3 extensions, as well as AVX2 instructions (except VGATHER).

PNaCl

• PNaCl supports C11/C++11 memory orders acquire, release, and acq_rel. It used to upgrade all accesses to seq_cst. It still upgrades consume to acquire (no compiler currently implements consume), and relaxed to seq_cst (to conservatively avoid platform differences due to out-of-thin-air problems). This is currently disabled by default in the SDK so that the in-browser translator installed on users’ machines has time to gain this support. Developers can turn it on by passing the -pnacl-memory-order-seq-cst-only=false flag to opt.
• PNaCl handles nested struct type expansion, which allows it to better support non-C languages such as Rust.
• PNaCl breaks up many integer operations over 64-bits into individual 64-bit operations. This is often encountered when using large consecutive bitfields.

Chrome/Pepper 41 (09 January 2015)

NaCl

• The x86 NaCl validators accept instructions from the AVX1 extensions.

PNaCl

• PNaCl is now based on LLVM 3.5.

Chrome/Pepper 40 (November 07 2014)

• VideoDecoder is now stable, see the SDK example in pepper_canary/examples/api/video_decode.

Chrome/Pepper 39 (26 September 2014)

NaCl

• This release contains a fix for CVE-2015-0565: disable the x86 CLFLUSH instruction due to rowhammer problem.

Pepper

• Support for DEBUG_ONLY:dev://postmessage has been removed in favor of other more useful debugging approaches.
• postMessageAndAwaitResponse is now stable and allows JavaScript to communicate synchronously with PNaCl embeds.

Chrome/Pepper 38 (15 August 2014)

PNaCl

• Compilation speed improvements due to validation caching of the translator and linker.
• Performance improvement of SIMD vector shuffle.

Chrome/Pepper 37 (20 June 2014)

PNaCl

• 2–10% translation time improvement.
• Improved vector load/store and shuffle performance.

Pepper

• Media Streams Input support.
• Compositor API.
• Hardware Decode API in development preview.
• Sync API in development preview.

SDK

• Demo of a full development environment in the browser.

Chrome/Pepper 36 (09 May 2014)

PNaCl

• Support LLVM vectors and GCC vectors for SIMD vectors through Portable SIMD Vectors. Note that this is still an early release, and performance is expected to become acceptable for version 37 of Chrome. More SIMD instructions will be added in later releases.

Chrome/Pepper 35 (31 Mar 2014)

PNaCl

• Upgraded LLVM to version 3.4.
• Translation now uses dynamic load balancing, making translation time faster.
• Unstable pexes (i.e. non-finalized) with debug information can be loaded by Chrome, simplifying debugging with PNaCl. See Debugging PNaCl pexes

Chrome/Pepper 34 (20 Feb 2014)

Pepper

• Filesystems can now be passed from JavaScript to NaCl. The resulting pp::Var will contain a pp::Resource that can be given to the pp::FileSystem constructor.
• New Audio and Video input APIs have been added as dev interfaces. See pp::MediaStreamAudioTrack and pp::MediaStreamVideoTrack for more details.

PNaCl

• Parallel translation: at least 1.7x faster, even with older pexes.
• Intelligent abbreviations in the bitcode: 20% reduction in binary size using the pnacl-compress tool.

Chrome/Pepper 33 (16 Dec 2013)

Portable Native Client

• PNaCl’s default C++ standard library is now LLVM’s own libc++, based on LLVM 3.3. This library now supports optional setjmp/longjmp exception handling (see announcement for details).

SDK

• The nacl_io library now includes a FUSE mount.
• In the SDK examples, common.js now loads the Release version of the nexes/pexes that are built (by default).
• “make debug” and “make run” have been fixed on Mac.

PNaCl enabled by default in Chrome 31 (12 Nov 2013)

• Portable Native Client (PNaCl) is enabled by default in Chrome 31. See NaCl and PNaCl for details on the differences between NaCl and PNaCl.
• The PNaCl ABI has changed from the preview release in Chrome 30. Pexe modules built with the pepper_30 bundle in the SDK must be recompiled with the pepper_31 bundle or later. As a general rule, we always recommended building applications with the latest stable bundle in the Native Client SDK. The PNaCl ABI will remain stable starting with the release of Chrome 31.

• Additional changes in the Chrome/Pepper 31 release:

  • Updates to the Pepper API, including socket and network support
  • Improved socket support in the nacl_io library

PNaCl in Chrome 30 Dev channel (01 Aug 2013)

• Portable Native Client (PNaCl) is currently available for preview in Chrome 30 (currently in the Dev channel). Apps and sites built with PNaCl can run in Chrome 30 without an explicit flag.
• See Introduction to Portable Native Client for information on developing for PNaCl. More documentation will be available soon.
• Please note that the PNaCl bitcode ABI may still change before the official public release; if you’re developing a PNaCl-based application, be sure to build your code with the latest version of the Native Client SDK.
• Update: PNaCl is not enabled by default in beta or stable versions of M30.

PNaCl (15 May 2013)

• Portable Native Client (PNaCl) is currently available for developer preview in Chrome 29 or higher.
• To produce a PNaCl executable (.pexe) file, you must use the pnacl toolchain in the current pepper_canary bundle. Chrome 29 does not support .pexe files produced by earlier versions of the pnacl toolchain (that is, executables compiled with the pepper_28 bundle or earlier).
• To run an application with a PNaCl module, you must launch Chrome 29 with the --enable-pnacl flag (for Chrome apps), or the --enable-nacl flag (for other apps).
• When you launch Chrome with the --enable-pnacl flag, Chrome loads a PNaCl translator in the background. Wait about a minute after you launch Chrome and check chrome://nacl to verify that the translator loaded.
• PNaCl translators are currently available for 32-bit x86, 64-bit x86, and ARM architectures.
• PNaCl applications must use the newlib C library (glibc and dynamic linking are not supported yet).
• The intermediate representation (IR) format may change prior to the release of PNaCl. If so, you will need to recompile your application with the pnacl toolchain in a new SDK bundle.

Pepper 27 (12 April 2013)

The Pepper 27 bundle features a significant number of new libraries that have been incorporated directly into the SDK.

Libraries

• A number of libraries from the naclports project have been incorporated directly into the Native Client SDK. These libraries include:

  • image encoding/decoding: jpeg, tiff, png, webp
  • multimedia: openal, freealut, ogg, vorbis
  • XML parsing: tinyxml, xml2
  • miscellaneous: zlib (general purpose compression), freetype (font rendering), lua (Lua interpreter)

  The libraries are located in ports/lib, and the header files are in ports/include.

• The httpfs filesystem in the nacl_io library now caches content in memory by default; this improves performance considerably.
• For applications compiled with a glibc toolchain, dlopen() can now be used to open shared libraries that are not specified in an application’s Native Client manifest (.nmf) file. This allows applications, for example, to download a shared object and then use dlopen() to access the shared object. The dlopen example has been modified to demonstrate this functionality: reverse.cc is built into a shared object (.so) file, which is downloaded and opened using an httpfs mount.

Examples

• Each example now has a single index.html file, instead of multiple HTML files corresponding to NaCl modules built using different toolchains and configurations. By default, most examples are built using one toolchain (newlib) and one configuration (Debug). If you build an example using multiple toolchains or configurations, you can specify which version to run in Chrome using the query parameters tc and config. For example, assuming you are serving an example from the local server localhost:5103, you can run a version of the example built with the glibc toolchain in the Release configuration by specifying the following URL in Chrome: http://localhost:5103/index.html?tc=glibc&config=Release. For additional information about how different NaCl modules are loaded into index.html, see the common.js file in each example.

Build tools and toolchains

• Common makefiles, including tools/common.mk, can now handle source files located outside of an application’s root directory. For example, a Makefile for an application can specify a source file to compile such as ../../some/other/place.cpp.

Pepper 26 (29 March 2013)

The Pepper 26 bundle includes a new HTTP filesystem type in the nacl_mounts library (which has been renamed nacl_io), changes to the example Makefiles, a simple new 3D example, and a threaded file IO example.

Build tools and toolchains

• Makefiles have been changed significantly:

  • Build commands are now specified in a number of common files (tools/*.mk), which are included in the Makefiles in the examples.
  • By default, make displays a simplified list of build steps (e.g., CC newlib/Debug/hello_world_x86_32.o) rather than the actual build commands. To see the actual build commands, run make V=1.
  • By default, most examples are built using one toolchain (newlib) and one configuration (Debug). To build an example using a different toolchain or configuration, run make with the parameters TOOLCHAIN=<x> or CONFIG=<y>. You can also run make all_versions to build an example with all toolchains.
• Header files have been moved out of the toolchains. All toolchains now share the same set of header files as host builds. Previously host and NaCl builds used different headers, which could cause build problems.

Libraries

• The nacl_mounts library has been renamed nacl_io, and has been expanded with a new type of mount, httpfs, which can be used to read URLs via HTTP. For details see include/nacl_io/nacl_io.h, as well as the hello_nacl_io example.

Examples

• A new example, hello_world_instance3d, has been added to demonstrate a simplified 3D app.
• The file_io example has been rewritten to do all file operations on a thread. The example demonstrates how to use the MessageLoop API and blocking callbacks on a thread.

General

• Old bundles (pepper_20 and earlier) have been removed from the Native Client SDK Manifest, and will no longer be updated by the naclsdk command.

Pepper 25 (21 December 2012)

The Pepper 25 bundle features an ARM toolchain to build Native Client modules for ARM devices, two new Pepper APIs (including the MessageLoop API, which lets you make Pepper calls on background threads), two new libraries (nacl_mounts, which provides a virtual file system that you can use with standard C file operations, and ppapi_main, which lets you implement a Native Client module using a simple ppapi_main function), and two new examples that demonstrate how to use the nacl_mounts and ppapi_main libraries.

Build tools and toolchains

• The SDK includes a new toolchain to build Native Client executables (.nexe files) for ARM devices.

  • Currently the ARM toolchain can only be used to compile modules that use the newlib C library. You cannot use the ARM toolchain to compile modules that use the glibc library.
  • The ARM toolchain is in the directory pepper_25/toolchain/<host>_arm_newlib. The bin subdirectory contains the compiler (arm-nacl-gcc), the linker (arm-nacl-g++), and the other tools in the toolchain.
  • Take a look at the hello_world example to see how to use the ARM toolchain. Go to examples/hello_world and run make. When the build finishes, the newlib/Debug and newlib/Release subdirectories will contain .nexe files for the x86-32, x86-64, and ARM target architecutes, and a Native Client manifest (.nmf file) that references those three .nexe files.
• The simple web server included in the SDK, httpd.py, has been moved from the examples/ directory to the tools/ directory. On Windows, you can run httpd.cmd (in the examples/ directory) to start the server.

PPAPI

Pepper 25 includes two new APIs:

• The Console API lets your module log messages to the JavaScript console in the Chrome browser.
• The MessageLoop API lets your module make PPAPI calls on a background thread. Once you’ve created a message loop resource, attached it to a thread, and run it, you can post work to the thread, including completion callbacks for asynchronous operations. For a C++ example of how to use the MessageLoop API, see pepper_25/include/ppapi/utility/threading/simple_thread.h. Note that you cannot make asynchronous PPAPI calls on a background thread without creating and using a message loop.

Libraries

The SDK includes two new libraries:

• The nacl_mounts library provides a virtual file system that your module can “mount” in a given directory tree. The file system can be one of several types:

  • “memfs” is an in-memory file system,
  • “dev” is a file system with various utility nodes (e.g., /dev/null, /dev/console[0-3], /dev/tty), and
  • “html5fs” is a persistent file system.

  Once you’ve mounted a file system in your module, you can use standard C library file operations: fopen, fread, fwrite, fseek, and fclose. How those operations are performed depends on the type of file system (e.g., for html5fs, the operations are performed using the Pepper FileIO API). For a list of the types of file systems you can mount, see include/nacl_mounts/nacl_mounts.h. For an example of how to use nacl_mounts, see examples/hello_nacl_mounts. Note that html5fs is subject to the same constraints as persistent local file IO in Chrome (for example, prior to using an html5fs file system, you must enable local file IO).

• The ppapi_main library simplifies the creation of a NaCl module by providing a familiar C programming environment. With this library, your module can have a simple entry point called ppapi_main(), which is similar to the standard C main() function, complete with argc and argv[] parameters. Your module can also use standard C functions such as printf(), fopen(), and fwrite(). For details see include/ppapi_main/ppapi_main.h. For an example of how to use ppapi_main, see examples/hello_world_stdio.

Header files for the new libraries are in the include/ directory, source files are in the src/ directory, and compiled libraries are in the lib/ directory.

Examples

• The SDK includes two new examples:

  • hello_nacl_mounts illustrates how to use standard C library file operations in a Native Client module through the use of the nacl_mounts library.
  • hello_world_stdio illustrates how to implement a Native Client module with a ppapi_main() function, and how to write to STDOUT and STDERR in a module, through the use of the nacl_mounts and ppapi_main libraries. This example makes it easy for new users to get started with Native Client by letting them start making changes in a familiar C environment.

• With a few exceptions, the Makefile for each example now builds the following versions of each example:

  • glibc toolchain: 32-bit and 64-bit .nexes for the x86 target architecture
  • newlib toolchain: 32-bit and 64-bit .nexes for the x86 target architecture, and ARM .nexe for the ARM architecture
  • pnacl toolchain: .pexe (which is subsequently tranlsated to .nexes for the x86-32, x86-64, and ARM architectures)
  • hosted toolchain: .so or .dll (to be executed as a Pepper plug-in in Chrome)
• Additionally, each version is built in both a Debug and a Release configuration.
• The Makefile for each example includes two new targets: make RUN and make LAUNCH. These targets, which are interchangeable, launch a local server and an instance of Chrome to run an example. When the instance of Chrome is closed, the local server is shut down as well.
• The hello_world_stdio example includes a simplified Makefile that only lists source dependencies, and invokes the build rules in a separate file (common.mk).

Pepper 24 (5 December 2012)

The Pepper 24 bundle features a new, experimental toolchain called PNaCl (short for “Portable Native Client”), a new library (pthreads-win32) for the Windows SDK, and an expanded list of attributes for Pepper 3D contexts that lets applications specify a GPU preference for low power or performance.

Build tools and toolchains

• The SDK includes a new, experimental toolchain called PNaCl (pronounced “pinnacle”). The PNaCl toolchain produces architecture-independent executable files (.pexe files). Chrome doesn’t yet support .pexe files directly, but if you want to experiment with this early preview of PNaCl, the toolchain includes a tool to translate .pexe files into architecture-specific .nexe files. Take a look at the hello_world example to see how to build a .pexe file and translate it into multiple .nexe files. Note that PNaCl is currently restricted to the newlib C standard library – if your application uses glibc, you can’t build it with PNaCl.
• The create_nmf.py script uses ELF headers (rather than file names) to determine the architecture of .nexe files. That means you can change the names of your .nexe files and create_nmf.py will still be able to generate the appropriate Native Client manifest file for your application.

Examples

• The SDK examples now build with four toolchains: the glibc and newlib toolchains, the experimental PNaCl toolchain, and the hosted toolchain on your development machine. Within each toolchain build, each example also builds both a debug and a release version.
• The example Makefiles use dependency (.d) files to enable incremental builds.
• The pong example has been cleaned up and modified to run more smoothly. The drawing function is now set up as the Flush() callback, which allows 2D drawing to occur as quickly as possible.

PPAPI

• When creating a 3D rendering context, the attribute list for the context can specify whether to prefer low power or performance for the GPU. Contexts with a low power preference may be created on an integrated GPU; contexts with a performance preference may be created on a discrete GPU.

Windows SDK

• The Windows SDK includes the pthreads-win32 library to assist in porting from win32 code. You can use this library when developing your module as a Pepper plug-in (.dll). See pepper_24/include/win/pthread.h and pepper_24/src/pthread/README for additional information.
• The update utility naclsdk.bat works when it is run from a path with spaces.

Pepper 23 (15 October 2012)

The Pepper 23 bundle includes support for the nacl-gdb debugger on Mac and 32-bit Windows, resources to enable hosted development on Linux, and changes to make the SDK examples compliant with version 2 of the Chrome Web Store manifest file format.

Tools

• The nacl-gdb debugger now works on all systems (Mac, Windows, and Linux).
• The output of the SDK update utility has been simplified. When you run the command naclsdk list, the utility displays one line for each available bundle, annotated with an “I” if the bundle is already installed on your system, and a “*” if the bundle has an update available. To see full information about a bundle, use the command naclsdk info <bundle> (for example, naclsdk info pepper_28).

Linux SDK

• Developers using the Linux SDK now have resources, including pre-built libraries and example Makefiles, that make it easier to build a module as a Pepper plugin (sometimes called a “trusted” or “in-process” plugin) using the native C/C++ compiler on their development system. In essence this makes developing a Native Client module a two-step process:

  1. Build the module into a shared library (.so file) using your system’s C/C++ compiler. Test and debug the .so file using the tools in your normal development environment.
  2. Build the module into a .nexe file using the compiler from one of the Native Client toolchains in the SDK (nacl-gcc or nacl-g++). Test and debug the .nexe file using nacl-gdb.

  This two step development process has many benefits—in particular, you can use the compilers, debuggers, profilers, and other tools that you’re already familiar with. But there are a few potential issues to keep in mind:

  • Chrome uses different threading models for trusted plugins and Native Client modules.
  • Certain operations such as platform-specific library calls and system calls may succeed during trusted development, but fail in Native Client.

  Here are the resources you can use to build your module into a Pepper plugin:

  • header files are in pepper_23/include
  • source files are in pepper_23/src
  • pre-built libraries are in pepper_23/lib

  You can now build and run most of the examples in the SDK as Pepper plugins.

  • Look at the example Makefiles or run make in the example directories to see the commands and flags used to build modules as Pepper plugins.
  • Run make LAUNCH in the example directories to see how to use the --register-pepper-plugins argument to load a Pepper plugin in Chrome. Note that you must set the CHROME_PATH environment variable and start a local server prior to running this command.

Examples

• On Linux and Windows systems, most of the examples now build with three toolchains: the Native Client glibc and newlib toolchains, and the native toolchain on the host system. Modules built with the native toolchain on the host system can only run as Pepper plugins.
• All examples in the SDK now comply with version 2 of the Chrome Web Store manifest file format. By default, applications that use version 2 of the manifest file format apply a strict content security policy, which includes a restriction against inline JavaScript. This restriction prohibits both inline <script> blocks and inline event handlers (e.g., <button onclick="...">). See Manifest Version for a list of changes between version 1 and version 2 of the manifest file format, and a support schedule for applications that use version 1.

PPAPI

• PP_InputEvent_Modifier has two new enum values (_ISLEFT and _ISRIGHT).
• The memory leak in the WebSocket API has been fixed.

Pepper 22 (22 August 2012)

The Pepper 22 bundle includes a command-line debugger, resources to enable hosted development on Windows, and changes to the example Makefiles (each example now builds both a debug and a release version).

Tools

• The SDK now includes a command-line debugger that you can use to debug Native Client modules. See Debugging with nacl-gdb for instructions on how to use this debugger. For now, nacl-gdb only works on 64-bit Windows, 64-bit Linux, and 32-bit Linux systems. Support for Mac and 32-bit Windows systems will be added soon.

Windows SDK

• Developers using the Windows SDK can now build a module as a Pepper plugin (sometimes called a “trusted” or “in-process” plugin) using the native C/C++ compiler on their development system. In essence this makes developing a Native Client module a two-step process:

  1. Build the module into a DLL using your system’s C/C++ compiler. Test and debug the DLL using the tools in your normal development environment.
  2. Build the module into a .nexe using the compiler from one of the Native Client toolchains in the SDK (nacl-gcc or nacl-g++). Test and debug the .nexe using nacl-gdb.

  This two step development process has many benefits—in particular, you can use the compilers, debuggers, profilers, and other tools that you’re already familiar with. But there are a few potential issues to keep in mind:

  • Some libraries that are commonly used with Native Client may not build easily on Windows.
  • You may need to put in extra effort to get source code to compile with multiple compilers, e.g., Microsoft Visual Studio and GCC.
  • Chrome uses different threading models for trusted plugins and Native Client modules.
  • Certain operations such as platform-specific library calls and system calls may succeed during trusted development, but fail in Native Client.

  Here are the resources you can use to build your module into a DLL:

  • header files are in pepper_22\include
  • source files are in pepper_22\src
  • pre-built libraries are in pepper_22\lib
• A Visual Studio add-in will be available in the near future with configurations that include platforms for both Pepper plugins and NaCl modules.

Examples

• Each example in the SDK now builds both a debug and a release version. As before, most examples also build newlib and glibc versions, which means that there are now four versions for each example. Take a look at the Makefiles in the examples to see the compiler flags that are used for debug and release versions. For a description of those flags, see Compile flags for different development scenarios.
• Comments have been added to common.js, which is used in all the examples. The JavaScript in common.js inserts an <embed> element that loads the NaCl module in each example’s web page, attaches event listeners to monitor the loading of the module, and implements handleMessage() to respond to messages sent from the NaCl module to the JavaScript side of the application

PPAPI

• The CompletionCallbackFactory class template now takes a thread traits class as its second parameter. For details see the CompletionCallbackFactory class template reference.