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Diffstat (limited to 'transect/001help.cc')
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diff --git a/transect/001help.cc b/transect/001help.cc deleted file mode 100644 index 3cab06d9..00000000 --- a/transect/001help.cc +++ /dev/null @@ -1,261 +0,0 @@ -//: Everything this project/binary supports. -//: This should give you a sense for what to look forward to in later layers. - -:(before "End Commandline Parsing") -if (argc <= 1 || is_equal(argv[1], "--help")) { - //: this is the functionality later layers will provide - // currently no automated tests for commandline arg parsing - if (argc <= 1) { - cerr << "Please provide a Mu program to run.\n" - << "\n"; - } - cerr << "Usage:\n" - << " mu [options] [test] [files]\n" - << "or:\n" - << " mu [options] [test] [files] -- [ingredients for function/recipe 'main']\n" - << "Square brackets surround optional arguments.\n" - << "\n" - << "Examples:\n" - << " To load files and run 'main':\n" - << " mu file1.mu file2.mu ...\n" - << " To run 'main' and dump a trace of all operations at the end:\n" - << " mu --trace file1.mu file2.mu ...\n" - << " To run all tests:\n" - << " mu test\n" - << " To load files and then run all tests:\n" - << " mu test file1.mu file2.mu ...\n" - << " To run a single Mu scenario:\n" - << " mu test file1.mu file2.mu ... scenario\n" - << " To run a single Mu scenario and dump a trace at the end:\n" - << " mu --trace test file1.mu file2.mu ... scenario\n" - << " To load files and run only the tests in explicitly loaded files (for apps):\n" - << " mu --test-only-app test file1.mu file2.mu ...\n" - << " To load all files with a numeric prefix in a directory:\n" - << " mu directory1 directory2 ...\n" - << " You can test directories just like files.\n" - << " mu test directory1 directory2 ...\n" - << " To pass ingredients to a mu program, provide them after '--':\n" - << " mu file_or_dir1 file_or_dir2 ... -- ingredient1 ingredient2 ...\n" - << " To see where a mu program is spending its time:\n" - << " mu --profile file_or_dir1 file_or_dir2 ...\n" - << " this slices and dices time spent in various profile.* output files\n" - << "\n" - << " To browse a trace generated by a previous run:\n" - << " mu browse-trace file\n" - ; - return 0; -} - -//: Support for option parsing. -//: Options always begin with '--' and are always the first arguments. An -//: option will never follow a non-option. -:(before "End Commandline Parsing") -char** arg = &argv[1]; -while (argc > 1 && starts_with(*arg, "--")) { - if (false) - ; // no-op branch just so any further additions can consistently always start with 'else' - // End Commandline Options(*arg) - else - cerr << "skipping unknown option " << *arg << '\n'; - --argc; ++argv; ++arg; -} - -//:: Helper function used by the above fragment of code (and later layers too, -//:: who knows?). -//: The :(code) directive appends function definitions to the end of the -//: project. Regardless of where functions are defined, we can call them -//: anywhere we like as long as we format the function header in a specific -//: way: put it all on a single line without indent, end the line with ') {' -//: and no trailing whitespace. As long as functions uniformly start this -//: way, our 'build*' scripts contain a little command to automatically -//: generate declarations for them. -:(code) -bool is_equal(char* s, const char* lit) { - return strncmp(s, lit, strlen(lit)) == 0; -} - -bool starts_with(const string& s, const string& pat) { - string::const_iterator a=s.begin(), b=pat.begin(); - for (/*nada*/; a!=s.end() && b!=pat.end(); ++a, ++b) - if (*a != *b) return false; - return b == pat.end(); -} - -//: I'll throw some style conventions here for want of a better place for them. -//: As a rule I hate style guides. Do what you want, that's my motto. But since -//: we're dealing with C/C++, the one big thing we want to avoid is undefined -//: behavior. If a compiler ever encounters undefined behavior it can make -//: your program do anything it wants. -//: -//: For reference, my checklist of undefined behaviors to watch out for: -//: out-of-bounds access -//: uninitialized variables -//: use after free -//: dereferencing invalid pointers: null, a new of size 0, others -//: -//: casting a large number to a type too small to hold it -//: -//: integer overflow -//: division by zero and other undefined expressions -//: left-shift by negative count -//: shifting values by more than or equal to the number of bits they contain -//: bitwise operations on signed numbers -//: -//: Converting pointers to types of different alignment requirements -//: T* -> void* -> T*: defined -//: T* -> U* -> T*: defined if non-function pointers and alignment requirements are same -//: function pointers may be cast to other function pointers -//: -//: Casting a numeric value into a value that can't be represented by the target type (either directly or via static_cast) -//: -//: To guard against these, some conventions: -//: -//: 0. Initialize all primitive variables in functions and constructors. -//: -//: 1. Minimize use of pointers and pointer arithmetic. Avoid 'new' and -//: 'delete' as far as possible. Rely on STL to perform memory management to -//: avoid use-after-free issues (and memory leaks). -//: -//: 2. Avoid naked arrays to avoid out-of-bounds access. Never use operator[] -//: except with map. Use at() with STL vectors and so on. -//: -//: 3. Valgrind all the things. -//: -//: 4. Avoid unsigned numbers. Not strictly an undefined-behavior issue, but -//: the extra range doesn't matter, and it's one less confusing category of -//: interaction gotchas to worry about. -//: -//: Corollary: don't use the size() method on containers, since it returns an -//: unsigned and that'll cause warnings about mixing signed and unsigned, -//: yadda-yadda. Instead use this macro below to perform an unsafe cast to -//: signed. We'll just give up immediately if a container's ever too large. -//: Basically, Mu is not concerned about this being a little slower than it -//: could be. (https://gist.github.com/rygorous/e0f055bfb74e3d5f0af20690759de5a7) -//: -//: Addendum to corollary: We're going to uniformly use int everywhere, to -//: indicate that we're oblivious to number size, and since Clang on 32-bit -//: platforms doesn't yet support multiplication over 64-bit integers, and -//: since multiplying two integers seems like a more common situation to end -//: up in than integer overflow. -:(before "End Includes") -#define SIZE(X) (assert((X).size() < (1LL<<(sizeof(int)*8-2))), static_cast<int>((X).size())) - -//: 5. Integer overflow is guarded against at runtime using the -ftrapv flag -//: to the compiler, supported by Clang (GCC version only works sometimes: -//: http://stackoverflow.com/questions/20851061/how-to-make-gcc-ftrapv-work). -:(before "atexit(reset)") -initialize_signal_handlers(); // not always necessary, but doesn't hurt -//? cerr << INT_MAX+1 << '\n'; // test overflow -//? assert(false); // test SIGABRT -:(code) -// based on https://spin.atomicobject.com/2013/01/13/exceptions-stack-traces-c -void initialize_signal_handlers() { - struct sigaction action; - bzero(&action, sizeof(action)); - action.sa_sigaction = dump_and_exit; - sigemptyset(&action.sa_mask); - sigaction(SIGABRT, &action, NULL); // assert() failure or integer overflow on linux (with -ftrapv) - sigaction(SIGILL, &action, NULL); // integer overflow on OS X (with -ftrapv) -} -void dump_and_exit(int sig, siginfo_t* /*unused*/, void* /*unused*/) { - switch (sig) { - case SIGABRT: - #ifndef __APPLE__ - cerr << "SIGABRT: might be an integer overflow if it wasn't an assert() failure or exception\n"; - _Exit(1); - #endif - break; - case SIGILL: - #ifdef __APPLE__ - cerr << "SIGILL: most likely caused by integer overflow\n"; - _Exit(1); - #endif - break; - default: - break; - } -} -:(before "End Includes") -#include <signal.h> - -//: For good measure we'll also enable SIGFPE. -:(before "atexit(reset)") -feenableexcept(FE_OVERFLOW | FE_UNDERFLOW); -//? assert(sizeof(int) == 4 && sizeof(float) == 4); -//? // | exp | mantissa -//? int smallest_subnormal = 0b00000000000000000000000000000001; -//? float smallest_subnormal_f = *reinterpret_cast<float*>(&smallest_subnormal); -//? cerr << "ε: " << smallest_subnormal_f << '\n'; -//? cerr << "ε/2: " << smallest_subnormal_f/2 << " (underflow)\n"; // test SIGFPE -:(before "End Includes") -#include <fenv.h> -:(code) -#ifdef __APPLE__ -// Public domain polyfill for feenableexcept on OS X -// http://www-personal.umich.edu/~williams/archive/computation/fe-handling-example.c -int feenableexcept(unsigned int excepts) { - static fenv_t fenv; - unsigned int new_excepts = excepts & FE_ALL_EXCEPT; - unsigned int old_excepts; - if (fegetenv(&fenv)) return -1; - old_excepts = fenv.__control & FE_ALL_EXCEPT; - fenv.__control &= ~new_excepts; - fenv.__mxcsr &= ~(new_excepts << 7); - return fesetenv(&fenv) ? -1 : old_excepts; -} -#endif - -//: 6. Map's operator[] being non-const is fucking evil. -:(before "Globals") // can't generate prototypes for these -// from http://stackoverflow.com/questions/152643/idiomatic-c-for-reading-from-a-const-map -template<typename T> typename T::mapped_type& get(T& map, typename T::key_type const& key) { - typename T::iterator iter(map.find(key)); - assert(iter != map.end()); - return iter->second; -} -template<typename T> typename T::mapped_type const& get(const T& map, typename T::key_type const& key) { - typename T::const_iterator iter(map.find(key)); - assert(iter != map.end()); - return iter->second; -} -template<typename T> typename T::mapped_type const& put(T& map, typename T::key_type const& key, typename T::mapped_type const& value) { - // map[key] requires mapped_type to have a zero-arg (default) constructor - map.insert(std::make_pair(key, value)).first->second = value; - return value; -} -template<typename T> bool contains_key(T& map, typename T::key_type const& key) { - return map.find(key) != map.end(); -} -template<typename T> typename T::mapped_type& get_or_insert(T& map, typename T::key_type const& key) { - return map[key]; -} -//: The contract: any container that relies on get_or_insert should never call -//: contains_key. - -//: 7. istreams are a royal pain in the arse. You have to be careful about -//: what subclass you try to putback into. You have to watch out for the pesky -//: failbit and badbit. Just avoid eof() and use this helper instead. -:(code) -bool has_data(istream& in) { - return in && !in.eof(); -} - -:(before "End Includes") -#include <assert.h> - -#include <iostream> -using std::istream; -using std::ostream; -using std::iostream; -using std::cin; -using std::cout; -using std::cerr; -#include <iomanip> - -#include <string.h> -#include <string> -using std::string; - -#include <algorithm> -using std::min; -using std::max; |