Debugging Legate Programs#

Pretty Printing#

To easily inspect some Legate objects, Legate provides pretty printers for GDB and LLDB. The source code for these printers is in the share/legate/gdb and share/legate/lldb directories, respectively.

Note

Pretty printers for GDB on Darwin/macOS are not currently supported.

The pretty printers support the following types: - legate::detail::SmallVector

Usage#

Commands to load these printers are provided in the .gdbinit and .lldbinit files at the root of the Legate repository. To load these printers automatically when running your debugger at the project root, GDB and LLDB must be given permission to load these init files automatically.

This can be done by adding the following to ~/.gdbinit:

set auto-load safe-path /path/to/legate/dir

and the following to ~/.lldbinit:

settings set target.load-cwd-lldbinit true

When running your debugger at project root, you can validate the printers are loaded in GDB by running info pretty-printer and seeing the legate printers are listed under the legate category:

(gdb) info pretty-printer
global pretty-printers:
  ...
  legate
    SmallVector
  ...

Similarly, you can validate the printers are loaded in LLDB by running type summary list and type synthetic list and seeing the Legate types are listed under the default category:

(lldb) type synthetic list
-----------------------
Category: default
-----------------------
legate::detail::SmallVector<.*>:  Python class legate_formatters.SmallVectorChildrenProvider

To confirm the pretty printers are working, you can create a Legate object and print it:

(gdb) p small_vec_var
$1 = legate::detail::SmallVector<unsigned long, 6> of size=3, mode=small = {0, 1, 2}

(lldb) p small_vec_var
(legate::detail::SmallVector<unsigned long>) size=2 mode=small {
  [0] = 0
  [1] = 1
  [2] = 2
}
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