// // Various compiling-to-JS parameters. These are simply variables present when the // JS compiler runs. To set them, do something like // // emcc -s OPTION1=VALUE1 -s OPTION2=VALUE2 [..other stuff..] // // See https://github.com/kripken/emscripten/wiki/Code-Generation-Modes/ // // Note that the values here are the defaults in -O0, that is, unoptimized // mode. See apply_opt_level in tools/shared.py for how -O1,2,3 affect these // flags. // // Tuning var QUANTUM_SIZE = 4; // This is the size of an individual field in a structure. 1 would // lead to e.g. doubles and chars both taking 1 memory address. This // is a form of 'compressed' memory, with shrinking and stretching // according to the type, when compared to C/C++. On the other hand // the normal value of 4 means all fields take 4 memory addresses, // as per the norm on a 32-bit machine. // // Changing this from the default of 4 is deprecated. var TARGET_X86 = 0; // For i386-pc-linux-gnu var TARGET_LE32 = 1; // For le32-unknown-nacl. 1 is normal, 2 is for the fastcomp llvm // backend using pnacl abi simplification var CORRECT_SIGNS = 1; // Whether we make sure to convert unsigned values to signed values. // Decreases performance with additional runtime checks. Might not be // needed in some kinds of code. // If equal to 2, done on a line-by-line basis according to // CORRECT_SIGNS_LINES, correcting only the specified lines. // If equal to 3, correcting all *but* the specified lines var CHECK_SIGNS = 0; // Runtime errors for signing issues that need correcting. // It is recommended to use this in // order to find if your code needs CORRECT_SIGNS. If you can get your // code to run without CORRECT_SIGNS, it will run much faster var ASSERTIONS = 1; // Whether we should add runtime assertions, for example to // check that each allocation to the stack does not // exceed it's size, whether all allocations (stack and static) are // of positive size, etc., whether we should throw if we encounter a bad __label__, i.e., // if code flow runs into a fault // ASSERTIONS == 2 gives even more runtime checks var VERBOSE = 0; // When set to 1, will generate more verbose output during compilation. var INVOKE_RUN = 1; // Whether we will run the main() function. Disable if you embed the generated // code in your own, and will call main() yourself at the right time (which you // can do with Module.callMain(), with an optional parameter of commandline args). var INIT_HEAP = 0; // Whether to initialize memory anywhere other than the stack to 0. var TOTAL_STACK = 5*1024*1024; // The total stack size. There is no way to enlarge the stack, so this // value must be large enough for the program's requirements. If // assertions are on, we will assert on not exceeding this, otherwise, // it will fail silently. var TOTAL_MEMORY = 16777216; // The total amount of memory to use. Using more memory than this will // cause us to expand the heap, which can be costly with typed arrays: // we need to copy the old heap into a new one in that case. var FAST_MEMORY = 2*1024*1024; // The amount of memory to initialize to 0. This ensures it will be // in a flat array. This only matters in non-typed array builds. var ALLOW_MEMORY_GROWTH = 0; // If false, we abort with an error if we try to allocate more memory than // we can (TOTAL_MEMORY). If true, we will grow the memory arrays at // runtime, seamlessly and dynamically. This has a performance cost though, // both during the actual growth and in general (the latter is because in // that case we must be careful about optimizations, in particular the // eliminator). Note that memory growth is only supported with typed // arrays. var MAX_SETJMPS = 20; // size of setjmp table allocated in each function invocation (that has setjmp) // Code embetterments var MICRO_OPTS = 1; // Various micro-optimizations, like nativizing variables var RELOOP = 0; // Recreate js native loops from llvm data var RELOOPER = 'relooper.js'; // Loads the relooper from this path relative to compiler.js var RELOOPER_BUFFER_SIZE = 20*1024*1024; // The internal relooper buffer size. Increase if you see assertions // on OutputBuffer. var USE_TYPED_ARRAYS = 2; // Use typed arrays for the heap. See https://github.com/kripken/emscripten/wiki/Code-Generation-Modes/ // 0 means no typed arrays are used. This mode disallows LLVM optimizations // 1 has two heaps, IHEAP (int32) and FHEAP (double), // and addresses there are a match for normal addresses. This mode disallows LLVM optimizations. // 2 is a single heap, accessible through views as int8, int32, etc. This is // the recommended mode both for performance and for compatibility. var USE_FHEAP = 1; // Relevant in USE_TYPED_ARRAYS == 1. If this is disabled, only IHEAP will be used, and FHEAP // not generated at all. This is useful if your code is 100% ints without floats or doubles var DOUBLE_MODE = 1; // How to load and store 64-bit doubles. Without typed arrays or in typed array mode 1, // this doesn't matter - these values are just values like any other. In typed array mode 2, // a potential risk is that doubles may be only 32-bit aligned. Forcing 64-bit alignment // in Clang itself should be able to solve that, or as a workaround in DOUBLE_MODE 1 we // will carefully load in parts, in a way that requires only 32-bit alignment. In DOUBLE_MODE // 0 we will simply store and load doubles as 32-bit floats, so when they are stored/loaded // they will truncate from 64 to 32 bits, and lose precision. This is faster, and might // work for some code (but probably that code should just use floats and not doubles anyhow). // Note that a downside of DOUBLE_MODE 1 is that we currently store the double in parts, // then load it aligned, and that load-store will make JS engines alter it if it is being // stored to a typed array for security reasons. That will 'fix' the number from being a // NaN or an infinite number. var UNALIGNED_MEMORY = 0; // If enabled, all memory accesses are assumed to be unaligned. (This only matters in // typed arrays mode 2 where alignment is relevant.) In unaligned memory mode, you // can run nonportable code that typically would break in JS (or on ARM for that // matter, which also cannot do unaligned reads/writes), at the cost of slowness var FORCE_ALIGNED_MEMORY = 0; // If enabled, assumes all reads and writes are fully aligned for the type they // use. This is true in proper C code (no undefined behavior), but is sadly // common enough that we can't do it by default. See SAFE_HEAP and CHECK_HEAP_ALIGN // for ways to help find places in your code where unaligned reads/writes are done - // you might be able to refactor your codebase to prevent them, which leads to // smaller and faster code, or even the option to turn this flag on. var PRECISE_I64_MATH = 1; // If enabled, i64 addition etc. is emulated - which is slow but precise. If disabled, // we use the 'double trick' which is fast but incurs rounding at high values. // Note that we do not catch 32-bit multiplication by default (which must be done in // 64 bits for high values for full precision) - you must manually set PRECISE_I32_MUL // for that. // If set to 2, we always include the i64 math code, which is necessary in the case // that we can't know at compile time that 64-bit math is needed. For example, if you // print 64-bit values with printf, but never add them, we can't know at compile time // and you need to set this to 2. var PRECISE_I32_MUL = 1; // If enabled, i32 multiplication is done with full precision, which means it is // correct even if the value exceeds the JS double-integer limit of ~52 bits (otherwise, // rounding will occur above that range). var PRECISE_F32 = 0; // 0: Use JS numbers for floating-point values. These are 64-bit and do not model C++ // floats exactly, which are 32-bit. // 1: Model C++ floats precisely, using Math.fround, polyfilling when necessary. This // can be slow if the polyfill is used on heavy float32 computation. // 2: Model C++ floats precisely using Math.fround if available in the JS engine, otherwise // use an empty polyfill. This will have less of a speed penalty than using the full // polyfill in cases where engine support is not present. var CLOSURE_ANNOTATIONS = 0; // If set, the generated code will be annotated for the closure // compiler. This potentially lets closure optimize the code better. var SKIP_STACK_IN_SMALL = 1; // When enabled, does not push/pop the stack at all in // functions that have no basic stack usage. But, they // may allocate stack later, and in a loop, this can be // very bad. In particular, when debugging, printf()ing // a lot can exhaust the stack very fast, with this option. // In particular, be careful with the autodebugger! (We do turn // this off automatically in that case, though.) var INLINE_LIBRARY_FUNCS = 1; // Will inline library functions that have __inline defined var INLINING_LIMIT = 0; // A limit on inlining. If 0, we will inline normally in LLVM and // closure. If greater than 0, we will *not* inline in LLVM, and // we will prevent inlining of functions of this size or larger // in closure. 50 is a reasonable setting if you do not want // inlining var OUTLINING_LIMIT = 0; // A function size above which we try to automatically break up // functions into smaller ones, to avoid the downsides of very // large functions (JS engines often compile them very slowly, // compile them with lower optimizations, or do not optimize them // at all). If 0, we do not perform outlining at all. // To see which funcs are large, you can inspect the source // in a debug build (-g2 or -g for example), and can run // tools/find_bigfuncs.py on that to get a sorted list by size. // Another possibility is to look in the web console in firefox, // which will note slowly-compiling functions. // You will probably want to experiment with various values to // see the impact on compilation time, code size and runtime // throughput. It is hard to say what values to start testing // with, but something around 20,000 to 100,000 might make sense. // (The unit size is number of AST nodes.) // Generated code debugging options var SAFE_HEAP = 0; // Check each write to the heap, for example, this will give a clear // error on what would be segfaults in a native build (like deferencing // 0). See preamble.js for the actual checks performed. // If equal to 2, done on a line-by-line basis according to // SAFE_HEAP_LINES, checking only the specified lines. // If equal to 3, checking all *but* the specified lines. Note // that 3 is the option you usually want here. var SAFE_HEAP_LOG = 0; // Log out all SAFE_HEAP operations var CHECK_HEAP_ALIGN = 0; // Check heap accesses for alignment, but don't do as // near extensive (or slow) checks as SAFE_HEAP. var SAFE_DYNCALLS = 0; // Show stack traces on missing function pointer/virtual method calls var RESERVED_FUNCTION_POINTERS = 0; // In asm.js mode, we cannot simply add function pointers to // function tables, so we reserve some slots for them. var ALIASING_FUNCTION_POINTERS = 0; // Whether to allow function pointers to alias if they have // a different type. This can greatly decrease table sizes // in asm.js, but can break code that compares function // pointers across different types. var FUNCTION_POINTER_ALIGNMENT = 2; // Byte alignment of function pointers - we will fill the // tables with zeros on aligned values. 1 means all values // are aligned and all will be used (which is optimal). // Sadly 1 breaks on &Class::method function pointer calls, // which llvm assumes have the lower bit zero (see // test_polymorph and issue #1692). var ASM_HEAP_LOG = 0; // Simple heap logging, like SAFE_HEAP_LOG but cheaper, and in asm.js var CORRUPTION_CHECK = 0; // When enabled, will emit a buffer area at the beginning and // end of each allocation on the heap, filled with canary // values that can be checked later. Corruption is checked for // at the end of each at each free() (see jsifier to add more, and you // can add more manual checks by calling CorruptionChecker.checkAll). // 0 means not enabled, higher values mean the size of the // buffer areas as a multiple of the allocated area (so // 1 means 100%, or buffer areas equal to allocated area, // both before and after). This must be an integer. var LABEL_DEBUG = 0; // 1: Print out functions as we enter them // 2: Also print out each label as we enter it var LABEL_FUNCTION_FILTERS = []; // Filters for function label debug. // The items for this array will be used // as filters for function names. Only the // labels of functions that is equaled to // one of the filters are printed out // When the array is empty, the filter is disabled. var EXCEPTION_DEBUG = 0; // Print out exceptions in emscriptened code. Does not work in asm.js mode var LIBRARY_DEBUG = 0; // Print out when we enter a library call (library*.js). You can also unset // Runtime.debug at runtime for logging to cease, and can set it when you // want it back. A simple way to set it in C++ is // emscripten_run_script("Runtime.debug = ...;"); var SOCKET_DEBUG = 0; // Log out socket/network data transfer. var SOCKET_WEBRTC = 0; // Select socket backend, either webrtc or websockets. var OPENAL_DEBUG = 0; // Print out debugging information from our OpenAL implementation. var GL_ASSERTIONS = 0; // Adds extra checks for error situations in the GL library. Can impact performance. var GL_DEBUG = 0; // Print out all calls into WebGL. As with LIBRARY_DEBUG, you can set a runtime // option, in this case GL.debug. var GL_TESTING = 0; // When enabled, sets preserveDrawingBuffer in the context, to allow tests to work (but adds overhead) var GL_MAX_TEMP_BUFFER_SIZE = 2097152; // How large GL emulation temp buffers are var GL_UNSAFE_OPTS = 1; // Enables some potentially-unsafe optimizations in GL emulation code var FULL_ES2 = 0; // Forces support for all GLES2 features, not just the WebGL-friendly subset. var LEGACY_GL_EMULATION = 0; // Includes code to emulate various desktop GL features. Incomplete but useful // in some cases, see https://github.com/kripken/emscripten/wiki/OpenGL-support var GL_FFP_ONLY = 0; // If you specified LEGACY_GL_EMULATION = 1 and only use fixed function pipeline in your code, // you can also set this to 1 to signal the GL emulation layer that it can perform extra // optimizations by knowing that the user code does not use shaders at all. If // LEGACY_GL_EMULATION = 0, this setting has no effect. var STB_IMAGE = 0; // Enables building of stb-image, a tiny public-domain library for decoding images, allowing // decoding of images without using the browser's built-in decoders. The benefit is that this // can be done synchronously, however, it will not be as fast as the browser itself. // When enabled, stb-image will be used automatically from IMG_Load and IMG_Load_RW. You // can also call the stbi_* functions directly yourself. var DISABLE_EXCEPTION_CATCHING = 0; // Disables generating code to actually catch exceptions. If the code you // are compiling does not actually rely on catching exceptions (but the // compiler generates code for it, maybe because of stdlibc++ stuff), // then this can make it much faster. If an exception actually happens, // it will not be caught and the program will halt (so this will not // introduce silent failures, which is good). // DISABLE_EXCEPTION_CATCHING = 0 - generate code to actually catch exceptions // DISABLE_EXCEPTION_CATCHING = 1 - disable exception catching at all // DISABLE_EXCEPTION_CATCHING = 2 - disable exception catching, but enables // catching in whitelist // TODO: Make this also remove cxa_begin_catch etc., optimize relooper // for it, etc. (perhaps do all of this as preprocessing on .ll?) var EXCEPTION_CATCHING_WHITELIST = []; // Enables catching exception in listed functions if // DISABLE_EXCEPTION_CATCHING = 2 set var EXECUTION_TIMEOUT = -1; // Throw an exception after X seconds - useful to debug infinite loops var CHECK_OVERFLOWS = 0; // Add code that checks for overflows in integer math operations. // There is currently not much to do to handle overflows if they occur. // We can add code to simulate i32/i64 overflows in JS, but that would // be very slow. It probably makes more sense to avoid overflows in // C/C++ code. For example, if you have an int that you multiply by // some factor, in order to get 'random' hash values - by taking // that |value & hash_table_size| - then multiplying enough times will overflow. // But instead, you can do |value = value & 30_BITS| in each iteration. var CHECK_SIGNED_OVERFLOWS = 0; // Whether to allow *signed* overflows - our correction for overflows generates signed // values (since we use &). This means that we correct some things are not strictly overflows, // and we cause them to be signed (which may lead to unnecessary unSign()ing later). // With this enabled, we check signed overflows for CHECK_OVERFLOWS var CORRECT_OVERFLOWS = 1; // Experimental code that tries to prevent unexpected JS overflows in integer // mathops, by doing controlled overflows (sort of parallel to a CPU). // Note that as mentioned above in CHECK_OVERFLOWS, the best thing is to // not rely on overflows in your C/C++ code, as even if this option works, // it slows things down. // // If equal to 2, done on a line-by-line basis according to // CORRECT_OVERFLOWS_LINES, correcting only the specified lines. // If equal to 3, correcting all *but* the specified lines // // NOTE: You can introduce signing issues by using this option. If you // take a large enough 32-bit value, and correct it for overflows, // you may get a negative number, as JS & operations are signed. var CORRECT_ROUNDINGS = 1; // C rounds to 0 (-5.5 to -5, +5.5 to 5), while JS has no direct way to do that: // Math.floor is to negative, ceil to positive. With CORRECT_ROUNDINGS, // we will do slow but correct C rounding operations. var FS_LOG = 0; // Log all FS operations. This is especially helpful when you're porting // a new project and want to see a list of file system operations happening // so that you can create a virtual file system with all of the required files. var CASE_INSENSITIVE_FS = 0; // If set to nonzero, the provided virtual filesystem if treated case-insensitive, like // Windows and OSX do. If set to 0, the VFS is case-sensitive, like on Linux. var USE_BSS = 1; // https://en.wikipedia.org/wiki/.bss // When enabled, 0-initialized globals are sorted to the end of the globals list, // enabling us to not explicitly store the initialization value for each 0 byte. // This significantly lowers the memory initialization array size. var NAMED_GLOBALS = 0; // If 1, we use global variables for globals. Otherwise // they are referred to by a base plus an offset (called an indexed global), // saving global variables but adding runtime overhead. var EXPORTED_FUNCTIONS = ['_main', '_malloc']; // Functions that are explicitly exported. These functions are kept alive // through LLVM dead code elimination, and also made accessible outside of // the generated code even after running closure compiler (on "Module"). // Note the necessary prefix of "_". var EXPORT_ALL = 0; // If true, we export all the symbols. Note that this does *not* affect LLVM, so it can // still eliminate functions as dead. This just exports them on the Module object. var EXPORT_BINDINGS = 0; // Export all bindings generator functions (prefixed with emscripten_bind_). This // is necessary to use the bindings generator with asm.js // JS library functions (C functions implemented in JS) // that we include by default. If you want to make sure // something is included by the JS compiler, add it here. // For example, if you do not use some emscripten_* // C API call from C, but you want to call it from JS, // add it here (and in EXPORTED FUNCTIONS with prefix // "_", for closure). var DEFAULT_LIBRARY_FUNCS_TO_INCLUDE = ['memcpy', 'memset', 'malloc', 'free', 'strlen', '$Browser']; var LIBRARY_DEPS_TO_AUTOEXPORT = ['memcpy']; // This list is also used to determine // auto-exporting of library dependencies (i.e., functions that // might be dependencies of JS library functions, that if // so we must export so that if they are implemented in C // they will be accessible, in ASM_JS mode). var IGNORED_FUNCTIONS = []; // Functions that we should not generate, neither a stub nor a complete function. // This is useful if your project code includes a function, and you want to replace // that in the compiled code with your own handwritten JS. (Of course even without // this option, you could just override the generated function at runtime. However, // JS engines might optimize better if the function is defined once in a single // place in your code.) var EXPORTED_GLOBALS = []; // Global non-function variables that are explicitly // exported, so they are guaranteed to be // accessible outside of the generated code. var INCLUDE_FULL_LIBRARY = 0; // Whether to include the whole library rather than just the // functions used by the generated code. This is needed when // dynamically loading modules that make use of runtime // library functions that are not used in the main module. // Note that this includes js libraries but *not* C. You will // need the main file to include all needed C libraries. For // example, if a library uses malloc or new, you will need // to use those in the main file too to link in dlmalloc. var SHELL_FILE = 0; // set this to a string to override the shell file used var SHOW_LABELS = 0; // Show labels in the generated code var PRINT_SPLIT_FILE_MARKER = 0; // Prints markers in Javascript generation to split the file later on. See emcc --split option. var MAIN_MODULE = 0; // A main module is a file compiled in a way that allows us to link it to // a side module using emlink.py. var SIDE_MODULE = 0; // Corresponds to MAIN_MODULE var BUILD_AS_SHARED_LIB = 0; // Whether to build the code as a shared library // 0 here means this is not a shared lib: It is a main file. // 1 means this is a normal shared lib, load it with dlopen() // 2 means this is a shared lib that will be linked at runtime, // which means it will insert its functions into // the global namespace. See STATIC_LIBS_TO_LOAD. // // Value 2 is currently deprecated. var RUNTIME_LINKED_LIBS = []; // If this is a main file (BUILD_AS_SHARED_LIB == 0), then // we will link these at runtime. They must have been built with // BUILD_AS_SHARED_LIB == 2. // NOTE: LLVM optimizations run separately on the main file and // linked libraries can break things. var BUILD_AS_WORKER = 0; // If set to 1, this is a worker library, a special kind of library // that is run in a worker. See emscripten.h var PROXY_TO_WORKER = 0; // If set to 1, we build the project into a js file that will run // in a worker, and generate an html file that proxies input and // output to/from it. var LINKABLE = 0; // If set to 1, this file can be linked with others, either as a shared // library or as the main file that calls a shared library. To enable that, // we will not internalize all symbols and cull the unused ones, in other // words, we will not remove unused functions and globals, which might be // used by another module we are linked with. // BUILD_AS_SHARED_LIB > 0 implies this, so it is only important to set this to 1 // when building the main file, and *if* that main file has symbols that // the library it will open will then access through an extern. // LINKABLE of 0 is very useful in that we can reduce the size of the // generated code very significantly, by removing everything not actually used. var DLOPEN_SUPPORT = 0; // Full support for dlopen. This is necessary for asm.js and for all code // modes for dlopen(NULL, ...). Note that you must use EMSCRIPTEN_KEEPALIVE // to ensure that functions and globals can be accessed through dlsym, // otherwise LLVM may optimize them out. var RUNTIME_TYPE_INFO = 0; // Whether to expose type info to the script at run time. This // increases the size of the generated script, but allows you // to more easily perform operations from handwritten JS on // objects with structures etc. var FAKE_X86_FP80 = 1; // Replaces x86_fp80 with double. This loses precision. It is better, // if you can, to get the original source code to build without x86_fp80 // (which is nonportable anyhow). var GC_SUPPORT = 1; // Enables GC, see gc.h (this does not add overhead, so it is on by default) var WARN_ON_UNDEFINED_SYMBOLS = 1; // If set to 1, we will warn on any undefined symbols that // are not resolved by the library_*.js files. Note that // it is common in large projects to // not implement everything, when you know what is not // going to actually be called (and don't want to mess with // the existing buildsystem), and functions might be // implemented later on, say in --pre-js, so you may // want to build with -s WARN_ON_UNDEFINED_SYMBOLS=0 to // disable the warnings if they annoy you. // See also ERROR_ON_UNDEFINED_SYMBOLS var ERROR_ON_UNDEFINED_SYMBOLS = 0; // If set to 1, we will give a compile-time error on any // undefined symbols (see WARN_ON_UNDEFINED_SYMBOLS). var SMALL_XHR_CHUNKS = 0; // Use small chunk size for binary synchronous XHR's in Web Workers. // Used for testing. // See test_chunked_synchronous_xhr in runner.py and library.js. var HEADLESS = 0; // If 1, will include shim code that tries to 'fake' a browser // environment, in order to let you run a browser program (say, // using SDL) in the shell. Obviously nothing is rendered, but // this can be useful for benchmarking and debugging if actual // rendering is not the issue. Note that the shim code is // very partial - it is hard to fake a whole browser! - so // keep your expectations low for this to work. var BENCHMARK = 0; // If 1, will just time how long main() takes to execute, and not // print out anything at all whatsoever. This is useful for benchmarking. var ASM_JS = 0; // If 1, generate code in asm.js format. If 2, emits the same code except // for omitting 'use asm' var PGO = 0; // Enables profile-guided optimization in the form of runtime checks for // which functions are actually called. Emits a list during shutdown that you // can pass to DEAD_FUNCTIONS (you can also emit the list manually by // calling PGOMonitor.dump()); var DEAD_FUNCTIONS = []; // Functions on this list are not converted to JS, and calls to // them are turned into abort()s. This is potentially useful for // reducing code size. // If a dead function is actually called, you will get a runtime // error. // This can affect both functions in compiled code, and system // library functions (e.g., you can use this to kill printf). // TODO: options to lazily load such functions var EXPLICIT_ZEXT = 0; // If 1, generate an explicit conversion of zext i1 to i32, using ?: var NECESSARY_BLOCKADDRS = []; // List of (function, block) for all block addresses that are taken. var JS_CHUNK_SIZE = 10240; // Used as a maximum size before breaking up expressions and lines into smaller pieces var EXPORT_NAME = 'Module'; // Global variable to export the module as for environments without a standardized module // loading system (e.g. the browser and SM shell). var RUNNING_JS_OPTS = 0; // whether js opts will be run, after the main compiler var COMPILER_ASSERTIONS = 0; // costly (slow) compile-time assertions var COMPILER_FASTPATHS = 1; // use fast-paths to speed up compilation // Compiler debugging options var DEBUG_TAGS_SHOWING = []; // Some useful items: // framework // frameworkLines // gconst // types // vars // relooping // unparsedFunctions // metadata // legalizer // The list of defines (C_DEFINES) was moved into struct_info.json in the same directory. // That file is automatically parsed by tools/gen_struct_info.py. // If you modify the headers, just clear your cache and emscripten libc should see // the new values.