#### 9.6.1 Dump setup

A dump_manager class is defined in `dumpfile.h`. Various passes register dumping pass-specific information via `dump_register` in `passes.c`. During the registration, an optimization pass can select its optimization group (see Optimization groups). After that optimization information corresponding to the entire group (presumably from multiple passes) can be output via command-line switches. Note that if a pass does not fit into any of the pre-defined groups, it can select `OPTGROUP_NONE`.

Note that in general, a pass need not know its dump output file name, whether certain flags are enabled, etc. However, for legacy reasons, passes could also call `dump_begin` which returns a stream in case the particular pass has optimization dumps enabled. A pass could call `dump_end` when the dump has ended. These methods should go away once all the passes are converted to use the new dump infrastructure.

The recommended way to setup the dump output is via `dump_start` and `dump_end`.