Estimated hours taken: 5
Fix the output of the declarative debugger so that it prints out
something that resembles a bug. Re-enable all the test cases,
and add some new ones. Add an `.exp2' file for each case, so
that tests work in debug grades as well as non-debug grades.
browser/declarative_debugger.m:
Output a text representation of the bug. The output is
rather unpretty, but allows us to check that the bug was
found correctly.
tests/debugger/declarative/Mmakefile:
Enable the new test cases. Re-enable the old ones.
tests/debugger/declarative/app.exp:
tests/debugger/declarative/gcf.exp:
tests/debugger/declarative/if_then_else.exp:
tests/debugger/declarative/oracle_db.exp:
tests/debugger/declarative/propositional.exp:
tests/debugger/declarative/queens.exp:
Update old test case results.
tests/debugger/declarative/app.exp2:
tests/debugger/declarative/gcf.exp2:
tests/debugger/declarative/if_then_else.exp2:
tests/debugger/declarative/oracle_db.exp2:
tests/debugger/declarative/propositional.exp2:
tests/debugger/declarative/queens.exp2:
Alternative results for old test cases.
tests/debugger/declarative/big.{m,inp,exp,exp2}:
tests/debugger/declarative/lpe_example.{m,inp,exp,exp2}:
tests/debugger/declarative/neg_conj.{m,inp,exp,exp2}:
tests/debugger/declarative/negation.{exp,exp2,inp}:
tests/debugger/declarative/small.{m,inp,exp,exp2}:
New test cases.
Estimated hours taken: 120
Implement the new architecture for the front end of the
declarative debugger. Disable declarative debugging if conservative
GC is not being used since this change relies on it. The benefits
of declarative debugging in non-GC grades are not worth the extra
maintenance required to support it, since even small examples require
a large amount of memory.
browser/declarative_analyser.m:
New module which handles the analysis of EDTs, which was
previously done in browser/declarative_debugger.m.
browser/declarative_debugger.m:
- Change the interface according to the new design.
- Export types of the form decl_*, rather than edt_*.
- Move the EDT analysis to the new module.
- Handle the interaction between the analyser and the oracle.
- Don't interact directly with the user, but go via the oracle.
- New diagnoser state type.
- Update the EDT instance to conform to the other changes.
browser/declarative_oracle.m:
- Replace oracle_answer type with oracle_response.
- Allow the oracle to work with a queue of questions rather
than one at a time.
- Add new predicates to manipulate the knowledge base.
browser/declarative_user.m:
- Export the user_state type.
- Handle some user commands in this module.
- Handle questions properly (apart from printing atoms).
browser/browser_library.m:
Add the new module.
trace/mercury_trace_declarative.c:
- Initialise the front end state just once per session.
- Make the step size much larger, since implicit subtrees
are not fully supported yet.
- Correct the types in a format specifier.
trace/mercury_trace_declarative.c:
trace/mercury_trace_internal.c:
trace/mercury_trace_internal.h:
- Disable declarative debugging unless conservative GC is used.
Estimated hours taken: 160
Implement a new data structure for declarative debugging. The
major differences between this and the old implementation are:
- The data structure is implemented in Mercury. The definition
of the type, and procedures for constructing values of that
type, have been moved from trace/mercury_trace_declarative.{c,h}
to browser/declarative_execution.m (which is a new module).
- The front end no longer needs to call the back end via an
indirect pointer---the front end does not call the back end at
all.
- The data structure is not specifically for wrong answer
analysis, it is intended to be used for any sort of analysis.
- The data structure represents execution at a lower level---the
new front end defines a more abstract view in terms of this
data structure.
Implement a test harness for debugging the front end code. This allows
the front end to run as a stand-alone program, which can then be
debugged using `mdb'.
The code in the front end does not currently handle the new structure
very nicely. This is because that code is about to undergo some major
structural changes, so there is little point cleaning it up now.
Consequently:
- Some of the code in the front end is incorrect (eg. the
user interface does not print missing answer nodes
properly).
- The tests have not been reinstated.
These things will be fixed in subsequent changes.
Likewise the compiler still reserves two stack slots, even though
only one is required. After this change the algorithm should be able
to get away with using no stack slots, so modifications to the compiler
will be postponed until then.
browser/declarative_execution.m:
New module. Implement the execution_tree typeclass, which
represents the execution of a Mercury program. Implement
two instances of this typeclass, one for normal use and one for
testing purposes.
browser/declarative_test.m:
New module. A test harness that can be compiled as a
stand-alone program, enabling the front end to be debugged.
trace/mercury_trace_declarative.c:
trace/mercury_trace_declarative.h:
- Remove the definition of the old data structure.
- Add some macros which enable the new Mercury data structure
to be destructively updated by C code.
- Change the interface to this module so that it reflects more
general diagnosis, not just wrong answer analysis.
- Implement the new algorithm.
- Call an alternative front end if in test mode.
- Update comments.
trace/mercury_trace_internal.h:
Add a new mode for debugging the declarative debugger.
trace/mercury_trace_internal.c:
Change the command from `dd_wrong' to `dd', since it is not
specifically for wrong answer analysis. Add a new command
`dd_dd' which calls the alternative front end used for testing.
runtime/mercury_init.h:
runtime/mercury_wrapper.c:
runtime/mercury_wrapper.h:
util/mkinit.c:
Remove any reference to `MR_edt_root_node', since it is no
longer used.
browser/declarative_debugger.m:
- Add a case for missing answer nodes to `edt_node'.
- Change the `evaluation_tree' typeclass into `mercury_edt'
typeclass. This is to make it more distinct from the new
`execution_tree' typeclass, which is a lower level concept.
- New interface to the diagnoser: types `diagnoser_response'
and `diagnoser_state', and procedure `diagnosis'.
- Define an instance of `mercury_edt' from an instance of
`execution_tree'.
- Updates to the analyser to get it to compile---further changes
will be forthcoming.
browser/declarative_user.m:
- Updates to the user interface to get it to compile---further
changes will be forthcoming.
browser/browser_library.m:
Import the new module (declarative_execution.m).
browser/debugger_interface.m:
browser/util.m:
Move the definitions of trace_port_type and goal_path_string
to browser/util.m, since they are now used by more than just
the external debugger.
browser/Mmakefile:
Add the test harness as a `depend' target.
browser/browse_test.m:
Use the correct interface to the browser.
Estimated hours taken: 55
This change adds a more sophisticated oracle to the declarative
debugger. The oracle now tries to remember previous answers and uses
them if available, and only asks the user if there is no other
information.
browser/declarative_oracle.m:
- Add the type "oracle_assumption", which identifies an
internal assumption of the oracle.
- Add the type "oracle_answer", which the oracle returns to the
caller. This holds either the truth value, or a reason why
the truth value cannot be given yet.
- Implement a knowledge base to store the previous answers.
This data structure is designed to be able to store arbitrary
assertions, although at this stage only one kind of assertion
is used.
- Where possible, use the KB to answer questions, instead of
asking the user.
- Update comments.
browser/declarative_debugger.m:
- Use the new interface to the oracle. Handle "don't know"
answers in a simple way: either save the question and ask it
later or return without finding any bug.
- Move the debugger_command type to this module.
- Move the UI stuff to a new module.
browser/declarative_user.m:
New module to handle interaction between the debugger/oracle
and the user.
tests/debugger/declarative/Mmakefile:
tests/debugger/declarative/oracle_db.{m,inp,exp}
Add a test case for the new feature.
Estimated hours taken: 12
Clean up the declarative debugger.
browser/declarative_debugger.m:
browser/declarative_oracle.m:
- Add a new type, oracle_data, to store the oracle database.
- Thread an oracle database through a single call to the
front end.
- Replace `unknown' with a less overloaded name in
some type definitions.
trace/mercury_trace_declarative.c:
trace/mercury_trace_declarative.h:
browser/declarative_debugger.m:
- Improve documentation.
browser/declarative_debugger.m:
- Export new type, edt_truth.
- Improve the interface to the oracle.
- Add a new typeclass, evaluation_tree, and update the
previous interface to reflect this.
- Make declarative_bug a polymorphic type, and change the
constructor for buggy nodes from `wrong' to `e_bug'.
Estimated hours taken: 2
Add the option `--enable-decl-debug' to configure, which enables
declarative debugging support in the internal debugger.
configure.in:
Add the option to configure.
browser/declarative_debugger.m:
runtime/mercury_wrapper.c:
Avoid using MR_address_of_edt_root_node unless configured
for declarative debugging.
runtime/mercury_conf.h.in:
runtime/mercury_conf_param.h:
Move the configuration macro to mercury_conf.h.in.
trace/mercury_trace_declarative.c:
Define MR_edt_root_node only if configured for declarative
debugging, thereby undoing a previous change.
Estimated hours taken: 3
Fix a bug causing the debugger tests to get link errors.
browser/declarative_debugger.m:
Call MR_edt_root_node indirectly via MR_address_of_edt_root_node.
runtime/mercury_wrapper.{c,h}:
Add a global function pointer, MR_address_of_edt_root_node.
util/mkinit.c:
Make sure MR_address_of_edt_root_node is initialized.
trace/mercury_trace_declarative.c:
Define MR_edt_root_node even if the declarative debugger is not
used.
Estimated hours taken: 80
Add a front end to the declarative debugger, written in Mercury. Modify
the back end to call this whenever an EDT is built. Also, various
bug fixes and improvements.
browser/declarative_debugger.m:
New module. This is a first implementation of the front end of
the declarative debugger. It uses a simple top-down algorithm
to search the EDT for a buggy node. The results are printed
in a simple format to the output stream. It is called from the
back end, in trace/mercury_trace_declarative.c.
browser/declarative_oracle.m:
New module. This is a first implementation of an oracle for the
declarative debugger. It simply passes all queries directly
on to the user.
browser/browser_library.m:
Import the new modules.
trace/mercury_trace_declarative.c:
- Various fixes/improvements of comments.
- Fix bugs where `int' is used instead of `Unsigned'.
- Pass the event_info structure to MR_trace_decl_update_path,
rather than passing various components of it.
- Use the copy of MR_trace_event_number in the event_info structure
rather than referring to the global variable directly.
- Remove the EDT printing functions, as they have been superseded by
the new front end. Call the new front end instead of these old
functions.
- Provide an interface to the EDT nodes that is imported by the
front end.
- Ensure that, after diagnosis, we end up at the same event we
started at.
- Fix a bug where it was assumed all procedures had at least one
argument.
- Ensure that the user is notified if the dd_wrong operation cannot
be started due to MR_trace_retry failing.
trace/mercury_trace_declarative.h:
- Move a #include to the correct place.
- Declare the interface to the EDT nodes.
trace/mercury_trace_internal.c:
Fix a bug introduced earlier.
runtime/mercury_conf_param.h:
Add a new configuration macro, MR_DEBUG_DD_BACK_END. When defined
this causes information about the declarative debugger back end
to be printed out during operation.
