Building with static checking

In addition to the normal errors and warnings provided by C++ compiler, there are often code patterns in Mozilla which are legal C++ but are nevertheless incorrect in various ways. Mozilla can now use a tool called Dehydra GCC to detect incorrect code and provide authors with instant feedback during the compile process.

Using Static Checking

Follow these steps to use static checking:

• Build GCC with plugin support (see instructions on the Dehydra GCC page)
• Build Dehydra GCC
• Add the following line to your .mozconfig file:

CXX=/path/to/gcc-with-plugin-support/bin/g++
ac_add_options --with-static-checking=/path/to/gcc_treehydra.so

As each C++ file in Mozilla is built, g++ will pass compilation information to config/static-checking.js. This script will perform Mozilla-specific code checking.

To change the analyses that are run, edit config/static-checking-config.mk.

Annotations

The following macros are currently used to annotate classes:

• NS_STACK_CLASS
• NS_FINAL_CLASS

The following macros are currently used to annotate methods:

• NS_OVERRIDE