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Estimated hours taken: 60 Branches: main Implement coverage testing. The output format is a bit crude, but people have been asking for this capability. The main problem tackled in this diff is that coverage testing requires gathering information from a lot of program executions, and the execution count files for all these executions require a huge amount of disk space. We now therefore put a limit on the number of files we keep; when this limit is exceeded, the program execution that reaches the limit will automatically summarize all these files back into a single file before it exits. This diff also tackles the same problem along a different axis by changing the format of execution count files to make them smaller. One way is to factor out and represent just once some information that is common to many procedures: the file name and the module name. Another is to abbreviate some keywords, e.g. "fproc" instead of "proc function". The third is not to write out the defining module's name unless it differs from the declaring module's name, which it almost never does. (The two differ only when the compiler is invoked with intermodule optimization, and creates a specialized version of a predicate in a module other than its home module.) Since we are changing the trace count file format anyway, make another change useful for coverage testing: record the entire provenance of the trace counts in the file, including the name of the program and what files went into unions and diffs of trace count files. When doing coverage testing of the compiler, the compiler *must* be in a debug grade. However, the tools for summarizing trace files, invoked from the compiler executable when the compiler is being coverage tested, *cannot* be in debug grade, because debug grade disables tail recursion, and without tail recursion the summarization program runs out of stack space. This diff therefore arranges for the slice directory to not be affected by the parameters applying to the rest of the workspace (including the top level Mmake.params). Mmakefile: Don't apply the top level mmake's parameters to recursive mmakes in the slice directory. Factor out some common code. configure.in: Require that the installed compiler contain the renamed standard library function names installed by my diff on Sep 20, since the slice directory needs them, and cannot get them from the workspace. mdbcomp/trace_counts.m: Update the parsing code to parse the new format for trace count files, and update the code for writing out trace counts to generate the new format. Replace the proc_label_and_filename type with the proc_label_in_context type, which makes it easier to keep track of the current module as well as the current file (this is required by the new, more compact format for trace count files). When considering the union of multiple trace counts files, keep track of whether they contained all counts or just the nonzero counts. This requires keeping track of this info for single files as well. Provide ways to represent and to compute differences between trace count files, to support the new program in slice/mtc_diff.m. mdbcomp/slice_and_dice.m: Reformat to conform to our Mercury style guide. Conform to the change to trace_counts.m. compiler/tupling.m: Conform to the change to mdbcomp. runtime/mercury_wrapper.c: Implement the new option values used to implement coverage testing. These allow control of the limit on the number of execution count files, and collecting execution counts only from a specified executable. Add MR_ prefixes. runtime/mercury_trace_base.[ch]: Provide the mechanism for summarizing execution counts when we reach the limit on the number of execution counts files. Update the code that writes out trace counts files to generate the new format for trace counts files. Make this code take the boolean that says whether to include labels with zero counts in the output as an explicit parameter, not as a global variable. Break up an excessively large function. scripts/mtc: Add the options needed to control the process of automatic summarization of trace counts files. slice/.mgnuc_copts: slice/.mgnuc_opts: slice/SLICE_FLAGS.in: Make these files empty, since we don't want to refer to the rest of the workspace. (We could delete them as well, but CVS doesn't handle resurrection of deleted files very well, and we don't want to burn any bridges.) slice/Mmakefile: Add the new executables, and make the code in this directory independent of the other directories in the workspace. Since we need the code of the modules in the mdbcomp directory but don't want to link to the object files in that directory (since the grades may differ), make copies of those modules in this directory. slice/mcov.m: Add this module, the code for the Mercury coverage test tool. slice/mtc_diff.m: Add this module, the code for computing the diff between two trace counts files. The intended use is to compare two trace counts files dumped at different stages of execution. (Since foreign_procs can be used to invoke the C functions in the runtime that write out the trace counts files in the middle of a program's execution, not just the end.) slice/mdice.m: slice/mslice.m: slice/mtc_union.m: Convert to four space indentation. tools/bootcheck: Since the slice directory's grade is independent of the grade of the other directories, don't copy it to the stage2 and stage3 by default. If it is copied, then still compile it (and otherwise handle it) separate from the other directories. Add an option for gathering coverage test data during bootchecking.
Mercury 0.13 may not work on Solaris 10 (SunOS 5.10) due to incompatibilities with the version of Boehm GC shipped with that version of Mercury. (The above problem has been fixed in post-0.13 versions of Mercury.) Also, note that `--linkage static' is not supported on Solaris. Executables produced using this option will cause a segmentation fault.