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Diffstat (limited to 'docs/users_guide/debug-info.rst')
| -rw-r--r-- | docs/users_guide/debug-info.rst | 27 |
1 files changed, 19 insertions, 8 deletions
diff --git a/docs/users_guide/debug-info.rst b/docs/users_guide/debug-info.rst index 6a34431c84..ecda4afc6c 100644 --- a/docs/users_guide/debug-info.rst +++ b/docs/users_guide/debug-info.rst @@ -7,13 +7,19 @@ useable by most UNIX debugging tools. .. ghc-flag:: -g -g⟨n⟩ + :shortdesc: Produce DWARF debug information in compiled object files. + ⟨n⟩ can be 0, 1, or 2, with higher numbers producing richer + output. If ⟨n⟩ is omitted, level 2 is assumed. + :type: dynamic + :category: debugging :since: 7.10, numeric levels since 8.0 Emit debug information in object code. Currently only DWARF debug information is supported on x86-64 and i386. Currently debug levels 0 - through 3 are accepted, with 0 disabling debug information production. - Levels 1 through 3 are functionally equivalent. + through 3 are accepted, with 0 disabling debug information production + and higher numbers producing richer output. If ⟨n⟩ is omitted, level 2 + is assumed. Tutorial @@ -180,16 +186,21 @@ Stack trace functionality is exposed for use by Haskell programs in the :base-ref:`GHC.ExecutionStack.` module. See the Haddock documentation in this module for details regarding usage. -Requesting a stack trace with ``SIGUSR2`` +.. _backtrace-signal: + +Requesting a stack trace with ``SIGQUIT`` ----------------------------------------- On POSIX-compatible platforms GHC's runtime system (when built with ``libdw`` -support) will produce a stack trace on ``stderr`` when a ``SIGUSR2`` signal is -received. For instance (using the same ``fib.hs`` as above), +support) will produce a stack trace on ``stderr`` when a ``SIGQUIT`` signal is +received (on many systems this signal can be sent using :kbd:`Ctrl-\\`). For +instance (using the same ``fib.hs`` as above), .. code-block:: sh - $ ./fib & killall -SIGUSR2 fib + $ ./fib & killall -SIGQUIT fib + + Caught SIGQUIT; Backtrace: 0x7f3176b15dd8 dwfl_thread_getframes (/usr/lib/x86_64-linux-gnu/libdw-0.163.so) 0x7f3176b1582f (null) (/usr/lib/x86_64-linux-gnu/libdw-0.163.so) 0x7f3176b15b57 dwfl_getthreads (/usr/lib/x86_64-linux-gnu/libdw-0.163.so) @@ -258,10 +269,10 @@ GHC may produce the following standard DIEs in the ``.debug_info`` section, Represents a compilation unit (e.g. a Haskell module). ``DW_TAG_subprogram`` - Represents a C-- top-level basic block. + Represents a C-\\- top-level basic block. ``DW_TAG_lexical_block`` - Represents a C-- basic block. Note that this is a slight departure from the + Represents a C-\\- basic block. Note that this is a slight departure from the intended meaning of this DIE type as it does not necessarily reflect lexical scope in the source program. |