dep: Add glslang

dep/glslang/README-spirv-remap.txt

@@ -0,0 +1,137 @@
+
+VERSION
+--------------------------------------------------------------------------------
+spirv-remap 0.97
+
+INTRO:
+--------------------------------------------------------------------------------
+spirv-remap is a utility to improve compression of SPIR-V binary files via
+entropy reduction, plus optional stripping of debug information and
+load/store optimization.  It transforms SPIR-V to SPIR-V, remapping IDs.  The
+resulting modules have an increased ID range (IDs are not as tightly packed
+around zero), but will compress better when multiple modules are compressed
+together, since compressor's dictionary can find better cross module
+commonality.
+
+Remapping is accomplished via canonicalization.  Thus, modules can be
+compressed one at a time with no loss of quality relative to operating on
+many modules at once.  The command line tool operates on multiple modules
+only in the trivial repetition sense, for ease of use.  The remapper API
+only accepts a single module at a time.
+
+There are two modes of use: command line, and a C++11 API.  Both are
+described below.
+
+spirv-remap is currently in an alpha state.  Although there are no known
+remapping defects, it has only been exercised on one real world game shader
+workload.
+
+
+FEEDBACK
+--------------------------------------------------------------------------------
+Report defects, enhancements requests, code improvements, etc to:
+   spvremapper@lunarg.com
+
+
+COMMAND LINE USAGE:
+--------------------------------------------------------------------------------
+Examples are given with a verbosity of one (-v), but more verbosity can be
+had via -vv, -vvv, etc, or an integer parameter to --verbose, such as
+"--verbose 4".  With no verbosity, the command is silent and returns 0 on
+success, and a positive integer error on failure.
+
+Pre-built binaries for several OSs are available.  Examples presented are
+for Linux.  Command line arguments can be provided in any order.
+
+1. Basic ID remapping
+
+Perform ID remapping on all shaders in "*.spv", writing new files with
+the same basenames to /tmp/out_dir.
+
+  spirv-remap -v --map all --input *.spv --output /tmp/out_dir
+
+2. Perform all possible size reductions
+
+  spirv-remap-linux-64 -v --do-everything --input *.spv --output /tmp/out_dir
+
+Note that --do-everything is a synonym for:
+
+  --map all --dce all --opt all --strip all
+
+API USAGE:
+--------------------------------------------------------------------------------
+
+The public interface to the remapper is defined in SPIRV/SPVRemapper.h as follows:
+
+namespace spv {
+
+class spirvbin_t
+{
+public:
+   enum Options { ... };
+   spirvbin_t(int verbose = 0);  // construct
+
+   // remap an existing binary in memory
+   void remap(std::vector<std::uint32_t>& spv, std::uint32_t opts = DO_EVERYTHING);
+
+   // Type for error/log handler functions
+   typedef std::function<void(const std::string&)> errorfn_t;
+   typedef std::function<void(const std::string&)> logfn_t;
+
+   // Register error/log handling functions (can be c/c++ fn, lambda fn, or functor)
+   static void registerErrorHandler(errorfn_t handler) { errorHandler = handler; }
+   static void registerLogHandler(logfn_t handler)     { logHandler   = handler; }
+};
+
+} // namespace spv
+
+The class definition is in SPVRemapper.cpp.
+
+remap() accepts an std::vector of SPIR-V words, modifies them per the
+request given in 'opts', and leaves the 'spv' container with the result.
+It is safe to instantiate one spirvbin_t per thread and process a different
+SPIR-V in each.
+
+The "opts" parameter to remap() accepts a bit mask of desired remapping
+options.  See REMAPPING AND OPTIMIZATION OPTIONS.
+
+On error, the function supplied to registerErrorHandler() will be invoked.
+This can be a standard C/C++ function, a lambda function, or a functor.
+The default handler simply calls exit(5); The error handler is a static
+member, so need only be set up once, not once per spirvbin_t instance.
+
+Log messages are supplied to registerLogHandler().  By default, log
+messages are eaten silently.  The log handler is also a static member.
+
+BUILD DEPENDENCIES:
+--------------------------------------------------------------------------------
+ 1. C++11 compatible compiler
+ 2. cmake
+ 3. glslang
+
+
+BUILDING
+--------------------------------------------------------------------------------
+The standalone remapper is built along side glslangValidator through its
+normal build process.
+
+
+REMAPPING AND OPTIMIZATION OPTIONS
+--------------------------------------------------------------------------------
+API:
+   These are bits defined under spv::spirvbin_t::, and can be
+   bitwise or-ed together as desired.
+
+   MAP_TYPES      = canonicalize type IDs
+   MAP_NAMES      = canonicalize named data
+   MAP_FUNCS      = canonicalize function bodies
+   DCE_FUNCS      = remove dead functions
+   DCE_VARS       = remove dead variables
+   DCE_TYPES      = remove dead types
+   OPT_LOADSTORE  = optimize unneeded load/stores
+   MAP_ALL        = (MAP_TYPES | MAP_NAMES | MAP_FUNCS)
+   DCE_ALL        = (DCE_FUNCS | DCE_VARS | DCE_TYPES)
+   OPT_ALL        = (OPT_LOADSTORE)
+   ALL_BUT_STRIP  = (MAP_ALL | DCE_ALL | OPT_ALL)
+   DO_EVERYTHING  = (STRIP | ALL_BUT_STRIP)
+