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| 1 # Introduction |
| 2 |
| 3 Eclipse can be used on Linux (and probably Windows and Mac) as an IDE for develo
ping Chromium. It's unpolished, but here's what works: |
| 4 |
| 5 * Editing code works well (especially if you're used to it or Visual Studio). |
| 6 * Navigating around the code works well. There are multiple ways to do this (F
3, control-click, outlines). |
| 7 * Building works fairly well and it does a decent job of parsing errors so tha
t you can click and jump to the problem spot. |
| 8 * Debugging is hit & miss. You can set breakpoints and view variables. STL con
tainers give it (and gdb) a bit of trouble. Also, the debugger can get into a ba
d state occasionally and eclipse will need to be restarted. |
| 9 * Refactoring seems to work in some instances, but be afraid of refactors that
touch a lot of files. |
| 10 |
| 11 # Setup |
| 12 |
| 13 ## Get & Configure Eclipse |
| 14 |
| 15 Eclipse 4.3 (Kepler) is known to work with Chromium for Linux. |
| 16 * Download the distribution appropriate for your OS. For example, for Linux 64
-bit/Java 64-bit, use the Linux 64 bit package from http://www.eclipse.org/downl
oads/ (Eclipse Packages Tab -> Linux 64 bit (link in bottom right)). |
| 17 * Tip: The packaged version of eclipse in distros may not work correctly wit
h the latest CDT plugin (installed below). Best to get them all from the same so
urce. |
| 18 * Googlers: The version installed on Goobuntu works fine. The UI will be muc
h more responsive if you do not install the google3 plug-ins. Just uncheck all
the boxes at first launch. |
| 19 * Unpack the distribution and edit the eclipse/eclipse.ini to increase the hea
p available to java. For instance: |
| 20 * Change -Xms40m to -Xms1024m (minimum heap) and -Xmx256m to -Xmx3072m (maxi
mum heap). |
| 21 * Googlers: Edit ~/.eclipse/init.sh to add this: |
| 22 ``` |
| 23 export ECLIPSE_MEM_START="1024M" |
| 24 export ECLIPSE_MEM_MAX="3072M" |
| 25 ``` |
| 26 The large heap size prevents out of memory errors if you include many Chrome sub
projects that Eclipse is maintaining code indices for. |
| 27 * Turn off Hyperlink detection in the Eclipse preferences. (Window -> Preferen
ces, search for "Hyperlinking, and uncheck "Enable on demand hyperlink style nav
igation"). |
| 28 |
| 29 Pressing the control key on (for keyboard shortcuts such as copy/paste) can trig
ger the hyperlink detector. This occurs on the UI thread and can result in the r
eading of jar files on the Eclipse classpath, which can tie up the editor due to
the size of the classpath in Chromium. |
| 30 |
| 31 ## A short word about paths |
| 32 |
| 33 Before you start setting up your work space - here are a few hints: |
| 34 * Don't put your checkout on a remote file system (e.g. NFS filer). It's too
slow both for building and for Eclipse. |
| 35 * Make sure there is no file system link in your source path because Ninja wil
l resolve it for a faster build and Eclipse / GDB will get confused. (Note: This
means that the source will possibly not reside in your user directory since it
would require a link from filer to your local repository.) |
| 36 * You may want to start Eclipse from the source root. To do this you can add a
n icon to your task bar as launcher. It should point to a shell script which wil
l set the current path to your source base, and then start Eclipse. The result w
ould probably look like this: |
| 37 ``` |
| 38 ~/.bashrc |
| 39 cd /usr/local/google/chromium/src |
| 40 export PATH=/home/skuhne/depot_tools:/usr/local/google/goma/goma:/opt/eclipse:/u
sr/local/symlinks:/usr/local/scripts:/usr/local/sbin:/usr/local/bin:/usr/sbin:/u
sr/bin:/sbin:/bin |
| 41 /opt/eclipse/eclipse -vm /usr/bin/java |
| 42 ``` |
| 43 |
| 44 (Note: Things work fine for me without launching Eclipse from a special director
y. jamescook@chromium.org 2012-06-1) |
| 45 |
| 46 ## Run Eclipse & Set your workspace |
| 47 |
| 48 Run eclipse/eclipse in a way that your regular build environment (export CC, CXX
, etc...) will be visible to the eclipse process. |
| 49 |
| 50 Set the Workspace to be a directory on a local disk (e.g. /work/workspaces/chrom
e). Placing it on an NFS share is not recommended -- it's too slow and Eclipse
will block on access. Don't put the workspace in the same directory as your che
ckout. |
| 51 |
| 52 ## Install the C Development Tools ("CDT") |
| 53 |
| 54 1. From the Help menu, select Install New Software... |
| 55 1. Select the URL for the CDT, http://download.eclipse.org/tools/cdt/release
s/kepler |
| 56 1. If it's not there you can click Add... and add it. |
| 57 1. Googlers: We have a local mirror, but be sure you run prodaccess before t
rying to use it. |
| 58 1. Select & install the Main and Optional features. |
| 59 1. Restart Eclipse |
| 60 1. Go to Window > Open Perspective > Other... > C/C++ to switch to the C++ per
spective (window layout). |
| 61 1. Right-click on the "Java" perspective in the top-right corner and select "C
lose" to remove it. |
| 62 |
| 63 ## Create your project(s) |
| 64 |
| 65 First, turn off automatic workspace refresh and automatic building, as Eclipse t
ries to do these too often and gets confused: |
| 66 |
| 67 1. Open Window > Preferences |
| 68 1. Search for "workspace" |
| 69 1. Turn off "Build automatically" |
| 70 1. Turn off "Refresh using native hooks or polling" |
| 71 1. Click "Apply" |
| 72 |
| 73 Create a single Eclipse project for everything: |
| 74 |
| 75 1. From the File menu, select New > Project... |
| 76 1. Select C/C++ Project > Makefile Project with Existing Code |
| 77 1. Name the project the exact name of the directory: "src" |
| 78 1. Provide a path to the code, like /work/chromium/src |
| 79 1. Select toolchain: Linux GCC |
| 80 1. Click Finish. |
| 81 |
| 82 Chromium has a huge amount of code, enough that Eclipse can take a very long tim
e to perform operations like "go to definition" and "open resource". You need t
o set it up to operate on a subset of the code. |
| 83 |
| 84 In the Project Explorer on the left side: |
| 85 |
| 86 1. Right-click on "src" and select "Properties..." |
| 87 1. Open Resource > Resource Filters |
| 88 1. Click "Add..." |
| 89 1. Add the following filter: |
| 90 * Include only |
| 91 * Files, all children (recursive) |
| 92 * Name matches `.*\.(c|cc|cpp|h|mm|inl|idl|js|json|css|html|gyp|gypi|grd|grd
p|gn)` regular expression |
| 93 1. Add another filter: |
| 94 * Exclude all |
| 95 * Folders |
| 96 * Name matches `out_.*|\.git|\.svn|LayoutTests` regular expression |
| 97 * If you aren't working on WebKit, adding `|WebKit` will remove more files |
| 98 1. Click "OK" |
| 99 |
| 100 Don't exclude the primary "out" directory, as it contains generated header files
for things like string resources and Eclipse will miss a lot of symbols if you
do. |
| 101 |
| 102 Eclipse will refresh the workspace and start indexing your code. It won't find
most header files, however. Give it more help finding them: |
| 103 |
| 104 1. Open Window > Preferences |
| 105 1. Search for "Indexer" |
| 106 1. Turn on "Allow heuristic resolution of includes" |
| 107 1. Select "Use active build configuration" |
| 108 1. Set Cache limits > Index database > Limit relative... to 20% |
| 109 1. Set Cache limits > Index database > Absolute limit to 256 MB |
| 110 1. Click "OK" |
| 111 |
| 112 Now the indexer will find many more include files, regardless of which approach
you take below. |
| 113 |
| 114 ### Optional: Manual header paths and symbols |
| 115 You can manually tell Eclipse where to find header files, which will allow it to
create the source code index before you do a real build. |
| 116 |
| 117 1. Right-click on "src" and select "Properties..." |
| 118 * Open C++ General > Paths and Symbols > Includes |
| 119 * Click "GNU C++" |
| 120 * Click "Add..." |
| 121 * Add /path/to/chromium/src |
| 122 * Check "Add to all configurations" and "Add to all languages" |
| 123 1. Repeat the above for: |
| 124 * /path/to/chromium/src/testing/gtest/include |
| 125 |
| 126 You may also find it helpful to define some symbols. |
| 127 |
| 128 1. Add OS\_LINUX: |
| 129 * Select the "Symbols" tab |
| 130 * Click "GNU C++" |
| 131 * Click "Add..." |
| 132 * Add name OS\_LINUX with value 1 |
| 133 * Click "Add to all configurations" and "Add to all languages" |
| 134 1. Repeat for ENABLE\_EXTENSIONS 1 |
| 135 1. Repeat for HAS\_OUT\_OF\_PROC\_TEST\_RUNNER 1 |
| 136 1. Click "OK". |
| 137 1. Eclipse will ask if you want to rebuild the index. Click "Yes". |
| 138 |
| 139 Let the C++ indexer run. It will take a while (10s of minutes). |
| 140 |
| 141 ## Optional: Building inside Eclipse |
| 142 This allows Eclipse to automatically discover include directories and symbols.
If you use gold or ninja (both recommended) you'll need to tell Eclipse about yo
ur path. |
| 143 |
| 144 1. echo $PATH from a shell and copy it to the clipboard |
| 145 1. Open Window > Preferences > C/C++ > Build > Environment |
| 146 1. Select "Replace native environment with specified one" (since gold and ninj
a must be at the start of your path) |
| 147 1. Click "Add..." |
| 148 1. For name, enter `PATH` |
| 149 1. For value, paste in your path with the ninja and gold directories. |
| 150 1. Click "OK" |
| 151 |
| 152 To create a Make target: |
| 153 |
| 154 1. From the Window menu, select Show View > Make Target |
| 155 1. In the Make Target view, right-click on the project and select New... |
| 156 1. name the target (e.g. base\_unittests) |
| 157 1. Unclick the Build Command: Use builder Settings and type whatever build com
mand you would use to build this target (e.g. "ninja -C out/Debug base\_unittest
s"). |
| 158 1. Return to the project properties page a under the C/C++ Build, change the B
uild Location/Build Directory to be /path/to/chromium/src |
| 159 1. In theory ${workspace\_loc} should work, but it doesn't for me. |
| 160 1. If you put your workspace in /path/to/chromium, then ${workspace\_loc:/sr
c} will work too. |
| 161 1. Now in the Make Targets view, select the target and click the hammer icon (
Build Make Target). |
| 162 |
| 163 You should see the build proceeding in the Console View and errors will be parse
d and appear in the Problems View. (Note that sometimes multi-line compiler erro
rs only show up partially in the Problems view and you'll want to look at the fu
ll error in the Console). |
| 164 |
| 165 (Eclipse 3.8 has a bug where the console scrolls too slowly if you're doing a fa
st build, e.g. with goma. To work around, go to Window > Preferences and search
for "console". Under C/C++ console, set "Limit console output" to 2147483647,
the maximum value.) |
| 166 |
| 167 ## Optional: Multiple build targets |
| 168 If you want to build multiple different targets in Eclipse (chrome, unit\_tests,
etc.): |
| 169 |
| 170 1. Window > Show Toolbar (if you had it off) |
| 171 1. Turn on special toolbar menu item (hammer) or menu bar item (Project > Buil
d configurations > Set Active > ...) |
| 172 1. Window > Customize Perspective... > "Command Groups Availability" |
| 173 1. Check "Build configuration" |
| 174 1. Add more Build targets |
| 175 1. Project > Properties > C/C++ Build > Manage Configurations |
| 176 1. Select "New..." |
| 177 1. Duplicate from current and give it a name like "Unit tests". |
| 178 1. Change under “Behavior” > Build > the target to e.g. “unit\_tests”. |
| 179 |
| 180 You can also drag the toolbar to the bottom of your window to save vertical spac
e. |
| 181 |
| 182 ## Optional: Debugging |
| 183 |
| 184 1. From the toolbar at the top, click the arrow next to the debug icon and sel
ect Debug Configurations... |
| 185 1. Select C/C++ Application and click the New Launch Configuration icon. This
will create a new run/debug configuration under the C/C++ Application header. |
| 186 1. Name it something useful (e.g. base\_unittests). |
| 187 1. Under the Main Tab, enter the path to the executable (e.g. .../out/Debug/ba
se\_unittests) |
| 188 1. Select the Debugger Tab, select Debugger: gdb and unclick "Stop on startup
in (main)" unless you want this. |
| 189 1. Set a breakpoint somewhere in your code and click the debug icon to start d
ebugging. |
| 190 |
| 191 ## Optional: Accurate symbol information |
| 192 |
| 193 If setup properly, Eclipse can do a great job of semantic navigation of C++ code
(showing type hierarchies, finding all references to a particular method even w
hen other classes have methods of the same name, etc.). But doing this well req
uires the Eclipse knows correct include paths and pre-processor definitions. Af
ter fighting with with a number of approaches, I've found the below to work best
for me. |
| 194 |
| 195 1. From a shell in your src directory, run GYP\_GENERATORS=ninja,eclipse build
/gyp\_chromium |
| 196 1. This generates <project root>/out/Debug/eclipse-cdt-settings.xml which is
used below. |
| 197 1. This creates a single list of include directories and preprocessor defini
tions to be used for all source files, and so is a little inaccurate. Here are
some tips for compensating for the limitations: |
| 198 1. Use `-R <target>` to restrict the output to considering only certain ta
rgets (avoiding unnecessary includes that are likely to cause trouble). Eg. for
a blink project, use `-R blink`. |
| 199 1. If you care about blink, move 'third\_party/Webkit/Source' to the top o
f the list to better resolve ambiguous include paths (eg. 'config.h'). |
| 200 1. Import paths and symbols |
| 201 1. Right click on the project and select Properties > C/C++ General > Paths
and Symbols |
| 202 1. Click Restore Defaults to clear any old settings |
| 203 1. Click Import Settings... > Browse... and select <project root>/out/Debug/
eclipse-cdt-settings.xml |
| 204 1. Click the Finish button. The entire preferences dialog should go away. |
| 205 1. Right click on the project and select Index > Rebuild |
| 206 |
| 207 ## Alternative: Per-file accurate include/pre-processor information |
| 208 |
| 209 Instead of generating a fixed list of include paths and pre-processor definition
s for a project (above), it is also possible to have Eclipse determine the corre
ct setting on a file-by-file basis using a built output parser. I (rbyers) used
this successfully for a long time, but it doesn't seem much better in practice
than the simpler (and less bug-prone) approach above. |
| 210 |
| 211 1. Install the latest version of Eclipse IDE for C/C++ developers ([Juno SR1](
http://www.eclipse.org/downloads/packages/eclipse-ide-cc-developers/junosr1) at
the time of this writing) |
| 212 1. Setup build to generate a build log that includes the g++ command lines for
the files you want to index: |
| 213 1. Project Properties -> C/C++ Build |
| 214 1. Uncheck "Use default build command" |
| 215 1. Enter your build command, eg: ninja -v |
| 216 1. Note that for better performance, you can use a command that doesn't
actually builds, just prints the commands that would be run. For ninja/make thi
s means adding -n. This only prints the compile commands for changed files (so b
e sure to move your existing out directory out of the way temporarily to force a
full "build"). ninja also supports "-t commands" which will print all build com
mands for the specified target and runs even faster as it doesn't have to check
file timestamps. |
| 217 1. Build directory: your build path including out/Debug |
| 218 1. Note that for the relative paths to be parsed correctly you can't use
ninja's ` '-C <dir>' ` to change directories as you might from the command line
. |
| 219 1. Build: potentially change "all" to the target you want to analyze, eg.
"chrome" |
| 220 1. Deselect 'clean' |
| 221 1. If you're using Ninja, you need to teach eclipse to ignore the prefix it
adds (eg. [10/1234] to each line in build output): |
| 222 1. Project properties -> C/C++ General -> Preprocessor includes |
| 223 1. Providers -> CDT GCC Build Output Parser -> Compiler command pattern |
| 224 1. ` (\[.*\] )?((gcc)|([gc]\+\+)|(clang(\+\+)?)) ` |
| 225 1. Note that there appears to be a bug with "Share setting entries between
projects" - it will keep resetting to off. I suggest using per-project setting
s and using the "folder" as the container to keep discovered entries ("file" may
work as well). |
| 226 1. Eclipse / GTK has bugs where lots of output to the build console can slow
down the UI dramatically and cause it to hang (basically spends all it's time t
rying to position the cursor correctly in the build console window). To avoid t
his, close the console window and disable automatically opening it on build: |
| 227 1. Preferences->C/C++->Build->Console -> Uncheck "Open console when buildi
ng" |
| 228 1. note you can still see the build log in ` <workspace>/.metadata/.plugin
s/org.eclipse.cdt.ui ` |
| 229 1. Now build the project (select project, click on hammer). If all went well: |
| 230 1. Right click on a cpp file -> properties -> C/C++ general -> Preprocessor
includes -> GNU C++ -> CDT GCC Build output Parser |
| 231 1. You will be able to expand and see all the include paths and pre-processo
r definitions used for this file |
| 232 1. Rebuild index (right-click on project, index, rebuild). If all went well: |
| 233 1. Open a CPP file and look at problems windows |
| 234 1. Should be no (or very few) errors |
| 235 1. Should be able to hit F3 on most symbols and jump to their definitioin |
| 236 1. CDT has some issues with complex C++ syntax like templates (eg. PassOwnPt
r functions) |
| 237 1. See [this page](http://wiki.eclipse.org/CDT/User/FAQ#Why_does_Open_Declar
ation_.28F3.29_not_work.3F_.28also_applies_to_other_functions_using_the_indexer.
29) for more information. |
| 238 |
| 239 ## Optional: static code and style guide analysis using cpplint.py |
| 240 |
| 241 1. From the toolbar at the top, click the Project -> Properties and go to C/C+
+Build. |
| 242 1. Click on the right side of the pop up windows, "Manage Configurations..."
, then on New, and give it a name, f.i. "Lint current file", and close the small
window, then select it in the Configuration drop down list. |
| 243 1. Under Builder settings tab, unclick "Use default build command" and type
as build command the full path to your depot\_tools/cpplint.py |
| 244 1. Under behaviour tab, unselect Clean, select Build(incremental build) and
in Make build target, add `--verbose=0 ${selected_resource_loc} ` |
| 245 1. Go back to the left side of the current window, and to C/C++Build -> Sett
ings, and click on error parsers tab, make sure CDT GNU C/C++ Error Parser, CDT
pushd/popd CWD Locator are set, then click Apply and OK. |
| 246 1. Select a file and click on the hammer icon drop down triangle next to it, a
nd make sure the build configuration is selected "Lint current file", then click
on the hammer. |
| 247 1. Note: If you get the cpplint.py help output, make sure you have selected a
file, by clicking inside the editor window or on its tab header, and make sure t
he editor is not maximized inside Eclipse, i.e. you should see more subwindows a
round. |
| 248 |
| 249 ## Additional tips |
| 250 1. Mozilla's [Eclipse CDT guide](https://developer.mozilla.org/en-US/docs/Ecli
pse_CDT) is helpful: |
| 251 1. For improved performance, I use medium-granularity projects (eg. one for We
bKit/Source) instead of putting all of 'src/' in one project. |
| 252 1. For working in Blink (which uses WebKit code style), feel free to use [this
](https://drive.google.com/file/d/0B2LVVIKSxUVYM3R6U0tUa1dmY0U/view?usp=sharing)
code-style formatter XML profile |
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