diff options
| -rw-r--r-- | documentation/mega-manual/figures/cross-development-toolchains.png | bin | 0 -> 59275 bytes | |||
| -rw-r--r-- | documentation/ref-manual/figures/cross-development-toolchains.png | bin | 0 -> 59275 bytes | |||
| -rw-r--r-- | documentation/ref-manual/technical-details.xml | 174 |
3 files changed, 174 insertions, 0 deletions
diff --git a/documentation/mega-manual/figures/cross-development-toolchains.png b/documentation/mega-manual/figures/cross-development-toolchains.png new file mode 100644 index 0000000000..d36670a198 --- /dev/null +++ b/documentation/mega-manual/figures/cross-development-toolchains.png | |||
| Binary files differ | |||
diff --git a/documentation/ref-manual/figures/cross-development-toolchains.png b/documentation/ref-manual/figures/cross-development-toolchains.png new file mode 100644 index 0000000000..d36670a198 --- /dev/null +++ b/documentation/ref-manual/figures/cross-development-toolchains.png | |||
| Binary files differ | |||
diff --git a/documentation/ref-manual/technical-details.xml b/documentation/ref-manual/technical-details.xml index 0634f5702d..f17291f2cb 100644 --- a/documentation/ref-manual/technical-details.xml +++ b/documentation/ref-manual/technical-details.xml | |||
| @@ -153,6 +153,180 @@ | |||
| 153 | </section> | 153 | </section> |
| 154 | </section> | 154 | </section> |
| 155 | 155 | ||
| 156 | <section id="cross-development-toolchain-generation"> | ||
| 157 | <title>Cross-Development Toolchain Generation</title> | ||
| 158 | |||
| 159 | <para> | ||
| 160 | The Yocto Project does most of the work for you when it comes to | ||
| 161 | creating | ||
| 162 | <ulink url='&YOCTO_DOCS_DEV_URL;#cross-development-toolchain'>cross-development toolchains</ulink>. | ||
| 163 | This section provides some technical background information on how | ||
| 164 | cross-development toolchains are created and used. | ||
| 165 | For more information on these toolchain, you can also see the | ||
| 166 | <ulink url='&YOCTO_DOCS_ADT_URL;'>the Yocto Project Application Developer's Guide</ulink>. | ||
| 167 | </para> | ||
| 168 | |||
| 169 | <para> | ||
| 170 | In the Yocto Project development environment, cross-development | ||
| 171 | toolchains are used to build the image and applications that run on the | ||
| 172 | target hardware. | ||
| 173 | With just a few commands, the OpenEmbedded build system creates | ||
| 174 | these necessary toolchains for you. | ||
| 175 | </para> | ||
| 176 | |||
| 177 | <para> | ||
| 178 | The following figure shows a high-level build environment regarding | ||
| 179 | toolchain construction and use. | ||
| 180 | </para> | ||
| 181 | |||
| 182 | <para> | ||
| 183 | <imagedata fileref="figures/cross-development-toolchains.png" width="8in" depth="6in" align="center" /> | ||
| 184 | </para> | ||
| 185 | |||
| 186 | <para> | ||
| 187 | Most of the work occurs on the Build Host. | ||
| 188 | This is the machine used to build images and generally work within the | ||
| 189 | the Yocto Project environment. | ||
| 190 | When you run BitBake to create an image, the OpenEmbedded build system | ||
| 191 | uses the host <filename>gcc</filename> compiler to bootstrap a | ||
| 192 | cross-compiler named <filename>gcc-cross</filename>. | ||
| 193 | The <filename>gcc-cross</filename> compiler is what BitBake uses to | ||
| 194 | compile source files when creating the target image. | ||
| 195 | You can think of <filename>gcc-cross</filename> simply as an | ||
| 196 | automatically generated cross-compiler that is used internally within | ||
| 197 | BitBake only. | ||
| 198 | </para> | ||
| 199 | |||
| 200 | <para> | ||
| 201 | The chain of events that occurs when <filename>gcc-cross</filename> is | ||
| 202 | bootstrapped is as follows: | ||
| 203 | <literallayout class='monospaced'> | ||
| 204 | gcc -> binutils-cross -> gcc-cross-initial -> linux_libc-headers -> eglibc-initial -> eglibc -> gcc-cross -> gcc-runtime | ||
| 205 | </literallayout> | ||
| 206 | <itemizedlist> | ||
| 207 | <listitem><para><filename>gcc</filename>: | ||
| 208 | The build host's GNU Compiler Collection (GCC). | ||
| 209 | </para></listitem> | ||
| 210 | <listitem><para><filename>binutils-cross</filename>: | ||
| 211 | The bare minimum binary utilities needed in order to run | ||
| 212 | the <filename>gcc-cross-initial</filename> phase of the | ||
| 213 | bootstrap operation. | ||
| 214 | </para></listitem> | ||
| 215 | <listitem><para><filename>gcc-cross-initial</filename>: | ||
| 216 | An early stage of the bootstrap process for creating | ||
| 217 | the cross-compiler. | ||
| 218 | This stage builds enough of the <filename>gcc-cross</filename>, | ||
| 219 | the C library, and other pieces needed to finish building the | ||
| 220 | final cross-compiler in later stages. | ||
| 221 | This tool is a "native" package (i.e. it is designed to run on | ||
| 222 | the build host). | ||
| 223 | </para></listitem> | ||
| 224 | <listitem><para><filename>linux_libc-headers</filename>: | ||
| 225 | Headers needed for the cross-compiler. | ||
| 226 | </para></listitem> | ||
| 227 | <listitem><para><filename>eglibc-initial</filename>: | ||
| 228 | An initial version of the Embedded GLIBC needed to bootstrap | ||
| 229 | <filename>eglibc</filename>. | ||
| 230 | </para></listitem> | ||
| 231 | <listitem><para><filename>gcc-cross</filename>: | ||
| 232 | The final stage of the bootstrap process for the | ||
| 233 | cross-compiler. | ||
| 234 | This stage results in the actual cross-compiler that | ||
| 235 | BitBake uses when it builds an image for a targeted | ||
| 236 | device. | ||
| 237 | <note> | ||
| 238 | If you are replacing this cross compiler toolchain | ||
| 239 | with a custom version, you must replace | ||
| 240 | <filename>gcc-cross</filename>. | ||
| 241 | </note> | ||
| 242 | This tool is also a "native" package (i.e. it is | ||
| 243 | designed to run on the build host). | ||
| 244 | </para></listitem> | ||
| 245 | <listitem><para><filename>gcc-runtime</filename>: | ||
| 246 | Runtime libraries resulting from the toolchain bootstrapping | ||
| 247 | process. | ||
| 248 | This tool produces a binary that consists of the | ||
| 249 | runtime libraries need for the targeted device. | ||
| 250 | </para></listitem> | ||
| 251 | </itemizedlist> | ||
| 252 | </para> | ||
| 253 | |||
| 254 | <para> | ||
| 255 | You can use the OpenEmbedded build system to build an installer for | ||
| 256 | the relocatable SDK used to develop applications. | ||
| 257 | When you run the installer, it installs the toolchain, which contains | ||
| 258 | the development tools (e.g., the | ||
| 259 | <filename>gcc-cross-canadian</filename>), | ||
| 260 | <filename>binutils-cross-canadian</filename>, and other | ||
| 261 | <filename>nativesdk-*</filename> tools you need to cross-compile and | ||
| 262 | test your software. | ||
| 263 | The figure shows the commands you use to easily build out this | ||
| 264 | toolchain. | ||
| 265 | This cross-development toolchain is built to execute on the | ||
| 266 | <filename>SDKMACHINE</filename>, which might or might not be the same | ||
| 267 | machine as the Build Host. | ||
| 268 | <note> | ||
| 269 | If your target architecture is supported by the Yocto Project, | ||
| 270 | you can take advantage of pre-built images that ship with the | ||
| 271 | Yocto Project and already contain cross-development toolchain | ||
| 272 | installers. | ||
| 273 | </note> | ||
| 274 | </para> | ||
| 275 | |||
| 276 | <para> | ||
| 277 | Here is the bootstrap process for the relocatable toolchain: | ||
| 278 | <literallayout class='monospaced'> | ||
| 279 | gcc -> binutils-crosssdk -> gcc-crosssdk-initial -> linux_libc-headers -> eglibc-initial -> nativesdk-eglibc -> gcc-crosssdk -> gcc-cross-canadian | ||
| 280 | </literallayout> | ||
| 281 | <itemizedlist> | ||
| 282 | <listitem><para><filename>gcc</filename>: | ||
| 283 | The build host's GNU Compiler Collection (GCC). | ||
| 284 | </para></listitem> | ||
| 285 | <listitem><para><filename>binutils-crosssdk</filename>: | ||
| 286 | The bare minimum binary utilities needed in order to run | ||
| 287 | the <filename>gcc-crosssdk-initial</filename> phase of the | ||
| 288 | bootstrap operation. | ||
| 289 | </para></listitem> | ||
| 290 | <listitem><para><filename>gcc-crosssdk-initial</filename>: | ||
| 291 | An early stage of the bootstrap process for creating | ||
| 292 | the cross-compiler. | ||
| 293 | This stage builds enough of the | ||
| 294 | <filename>gcc-crosssdk</filename> and supporting pieces so that | ||
| 295 | the final stage of the bootstrap process can produce the | ||
| 296 | finished cross-compiler. | ||
| 297 | This tool is a "native" binary that runs on the build host. | ||
| 298 | </para></listitem> | ||
| 299 | <listitem><para><filename>linux_libc-headers</filename>: | ||
| 300 | Headers needed for the cross-compiler. | ||
| 301 | </para></listitem> | ||
| 302 | <listitem><para><filename>eglibc-initial</filename>: | ||
| 303 | An initial version of the Embedded GLIBC needed to bootstrap | ||
| 304 | <filename>nativesdk-eglibc</filename>. | ||
| 305 | </para></listitem> | ||
| 306 | <listitem><para><filename>nativesdk-eglibc</filename>: | ||
| 307 | The Embedded GLIBC needed to bootstrap the | ||
| 308 | <filename>gcc-crosssdk</filename>. | ||
| 309 | </para></listitem> | ||
| 310 | <listitem><para><filename>gcc-crosssdk</filename>: | ||
| 311 | The final stage of the bootstrap process for the | ||
| 312 | relocatable cross-compiler. | ||
| 313 | The <filename>gcc-crosssdk</filename> is a transitory compiler | ||
| 314 | and never leaves the build host. | ||
| 315 | Its purpose is to help in the bootstrap process to create the | ||
| 316 | eventual relocatable <filename>gcc-cross-canadian</filename> | ||
| 317 | compiler, which is relocatable. | ||
| 318 | This tool is also a "native" package (i.e. it is | ||
| 319 | designed to run on the build host). | ||
| 320 | </para></listitem> | ||
| 321 | <listitem><para><filename>gcc-cross-canadian</filename>: | ||
| 322 | The final relocatable cross-compiler. | ||
| 323 | When run on the <filename>SDKMACHINE</filename>, this tool | ||
| 324 | produces executable code that runs on the target device. | ||
| 325 | </para></listitem> | ||
| 326 | </itemizedlist> | ||
| 327 | </para> | ||
| 328 | </section> | ||
| 329 | |||
| 156 | <section id="shared-state-cache"> | 330 | <section id="shared-state-cache"> |
| 157 | <title>Shared State Cache</title> | 331 | <title>Shared State Cache</title> |
| 158 | 332 | ||
