SPVRemapper.h

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//
// Copyright (C) 2015 LunarG, Inc.
//
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#ifndef SPIRVREMAPPER_H
#define SPIRVREMAPPER_H

#include <string>
#include <vector>
#include <cstdlib>
#include <exception>

namespace spv {

// MSVC defines __cplusplus as an older value, even when it supports almost all of 11.
// We handle that here by making our own symbol.
#if __cplusplus >= 201103L || _MSC_VER >= 1700
# define use_cpp11 1
#endif

class spirvbin_base_t
{
public:
 enum Options {
 NONE = 0,
 STRIP = (1<<0),
 MAP_TYPES = (1<<1),
 MAP_NAMES = (1<<2),
 MAP_FUNCS = (1<<3),
 DCE_FUNCS = (1<<4),
 DCE_VARS = (1<<5),
 DCE_TYPES = (1<<6),
 OPT_LOADSTORE = (1<<7),
 OPT_FWD_LS = (1<<8), // EXPERIMENTAL: PRODUCES INVALID SCHEMA-0 SPIRV
 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)
 };
};

} // namespace SPV

#if !defined (use_cpp11)
#include <cstdio>
#include <cstdint>

namespace spv {
class spirvbin_t : public spirvbin_base_t
{
public:
 spirvbin_t(int /*verbose = 0*/) { }

 void remap(std::vector<std::uint32_t>& /*spv*/, unsigned int /*opts = 0*/)
 {
 printf("Tool not compiled for C++11, which is required for SPIR-V remapping.\n");
 exit(5);
 }
};

} // namespace SPV

#else // defined (use_cpp11)

#include <functional>
#include <cstdint>
#include <unordered_map>
#include <unordered_set>
#include <map>
#include <set>
#include <cassert>

#include "spirv.hpp"
#include "spvIR.h"

namespace spv {

// class to hold SPIR-V binary data for remapping, DCE, and debug stripping
class spirvbin_t : public spirvbin_base_t
{
public:
 spirvbin_t(int verbose = 0) : entryPoint(spv::NoResult), largestNewId(0), verbose(verbose), errorLatch(false)
 { }

 virtual ~spirvbin_t() { }

 // remap on 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 lambda fn / functor / etc)
 static void registerErrorHandler(errorfn_t handler) { errorHandler = handler; }
 static void registerLogHandler(logfn_t handler) { logHandler = handler; }

protected:
 // This can be overridden to provide other message behavior if needed
 virtual void msg(int minVerbosity, int indent, const std::string& txt) const;

private:
 // Local to global, or global to local ID map
 typedef std::unordered_map<spv::Id, spv::Id> idmap_t;
 typedef std::unordered_set<spv::Id> idset_t;
 typedef std::unordered_map<spv::Id, int> blockmap_t;

 void remap(std::uint32_t opts = DO_EVERYTHING);

 // Map of names to IDs
 typedef std::unordered_map<std::string, spv::Id> namemap_t;

 typedef std::uint32_t spirword_t;

 typedef std::pair<unsigned, unsigned> range_t;
 typedef std::function<void(spv::Id&)> idfn_t;
 typedef std::function<bool(spv::Op, unsigned start)> instfn_t;

 // Special Values for ID map:
 static const spv::Id unmapped; // unchanged from default value
 static const spv::Id unused; // unused ID
 static const int header_size; // SPIR header = 5 words

 class id_iterator_t;

 // For mapping type entries between different shaders
 typedef std::vector<spirword_t> typeentry_t;
 typedef std::map<spv::Id, typeentry_t> globaltypes_t;

 // A set that preserves position order, and a reverse map
 typedef std::set<int> posmap_t;
 typedef std::unordered_map<spv::Id, int> posmap_rev_t;

 // Maps and ID to the size of its base type, if known.
 typedef std::unordered_map<spv::Id, unsigned> typesize_map_t;

 // handle error
 void error(const std::string& txt) const { errorLatch = true; errorHandler(txt); }

 bool isConstOp(spv::Op opCode) const;
 bool isTypeOp(spv::Op opCode) const;
 bool isStripOp(spv::Op opCode) const;
 bool isFlowCtrl(spv::Op opCode) const;
 range_t literalRange(spv::Op opCode) const;
 range_t typeRange(spv::Op opCode) const;
 range_t constRange(spv::Op opCode) const;
 unsigned typeSizeInWords(spv::Id id) const;
 unsigned idTypeSizeInWords(spv::Id id) const;

 spv::Id& asId(unsigned word) { return spv[word]; }
 const spv::Id& asId(unsigned word) const { return spv[word]; }
 spv::Op asOpCode(unsigned word) const { return opOpCode(spv[word]); }
 std::uint32_t asOpCodeHash(unsigned word);
 spv::Decoration asDecoration(unsigned word) const { return spv::Decoration(spv[word]); }
 unsigned asWordCount(unsigned word) const { return opWordCount(spv[word]); }
 spv::Id asTypeConstId(unsigned word) const { return asId(word + (isTypeOp(asOpCode(word)) ? 1 : 2)); }
 unsigned idPos(spv::Id id) const;

 static unsigned opWordCount(spirword_t data) { return data >> spv::WordCountShift; }
 static spv::Op opOpCode(spirword_t data) { return spv::Op(data & spv::OpCodeMask); }

 // Header access & set methods
 spirword_t magic() const { return spv[0]; } // return magic number
 spirword_t bound() const { return spv[3]; } // return Id bound from header
 spirword_t bound(spirword_t b) { return spv[3] = b; };
 spirword_t genmagic() const { return spv[2]; } // generator magic
 spirword_t genmagic(spirword_t m) { return spv[2] = m; }
 spirword_t schemaNum() const { return spv[4]; } // schema number from header

 // Mapping fns: get
 spv::Id localId(spv::Id id) const { return idMapL[id]; }

 // Mapping fns: set
 inline spv::Id localId(spv::Id id, spv::Id newId);
 void countIds(spv::Id id);

 // Return next unused new local ID.
 // NOTE: boost::dynamic_bitset would be more efficient due to find_next(),
 // which std::vector<bool> doens't have.
 inline spv::Id nextUnusedId(spv::Id id);

 void buildLocalMaps();
 std::string literalString(unsigned word) const; // Return literal as a std::string
 int literalStringWords(const std::string& str) const { return (int(str.size())+4)/4; }

 bool isNewIdMapped(spv::Id newId) const { return isMapped(newId); }
 bool isOldIdUnmapped(spv::Id oldId) const { return localId(oldId) == unmapped; }
 bool isOldIdUnused(spv::Id oldId) const { return localId(oldId) == unused; }
 bool isOldIdMapped(spv::Id oldId) const { return !isOldIdUnused(oldId) && !isOldIdUnmapped(oldId); }
 bool isFunction(spv::Id oldId) const { return fnPos.find(oldId) != fnPos.end(); }

 // bool matchType(const globaltypes_t& globalTypes, spv::Id lt, spv::Id gt) const;
 // spv::Id findType(const globaltypes_t& globalTypes, spv::Id lt) const;
 std::uint32_t hashType(unsigned typeStart) const;

 spirvbin_t& process(instfn_t, idfn_t, unsigned begin = 0, unsigned end = 0);
 int processInstruction(unsigned word, instfn_t, idfn_t);

 void validate() const;
 void mapTypeConst();
 void mapFnBodies();
 void optLoadStore();
 void dceFuncs();
 void dceVars();
 void dceTypes();
 void mapNames();
 void foldIds(); // fold IDs to smallest space
 void forwardLoadStores(); // load store forwarding (EXPERIMENTAL)
 void offsetIds(); // create relative offset IDs

 void applyMap(); // remap per local name map
 void mapRemainder(); // map any IDs we haven't touched yet
 void stripDebug(); // strip all debug info
 void stripDeadRefs(); // strips debug info for now-dead references after DCE
 void strip(); // remove debug symbols

 std::vector<spirword_t> spv; // SPIR words

 namemap_t nameMap; // ID names from OpName

 // Since we want to also do binary ops, we can't use std::vector<bool>. we could use
 // boost::dynamic_bitset, but we're trying to avoid a boost dependency.
 typedef std::uint64_t bits_t;
 std::vector<bits_t> mapped; // which new IDs have been mapped
 static const int mBits = sizeof(bits_t) * 4;

 bool isMapped(spv::Id id) const { return id < maxMappedId() && ((mapped[id/mBits] & (1LL<<(id%mBits))) != 0); }
 void setMapped(spv::Id id) { resizeMapped(id); mapped[id/mBits] |= (1LL<<(id%mBits)); }
 void resizeMapped(spv::Id id) { if (id >= maxMappedId()) mapped.resize(id/mBits+1, 0); }
 size_t maxMappedId() const { return mapped.size() * mBits; }

 // Add a strip range for a given instruction starting at 'start'
 // Note: avoiding brace initializers to please older versions os MSVC.
 void stripInst(unsigned start) { stripRange.push_back(range_t(start, start + asWordCount(start))); }

 // Function start and end. use unordered_map because we'll have
 // many fewer functions than IDs.
 std::unordered_map<spv::Id, range_t> fnPos;

 // Which functions are called, anywhere in the module, with a call count
 std::unordered_map<spv::Id, int> fnCalls;

 posmap_t typeConstPos; // word positions that define types & consts (ordered)
 posmap_rev_t idPosR; // reverse map from IDs to positions
 typesize_map_t idTypeSizeMap; // maps each ID to its type size, if known.

 std::vector<spv::Id> idMapL; // ID {M}ap from {L}ocal to {G}lobal IDs

 spv::Id entryPoint; // module entry point
 spv::Id largestNewId; // biggest new ID we have mapped anything to

 // Sections of the binary to strip, given as [begin,end)
 std::vector<range_t> stripRange;

 // processing options:
 std::uint32_t options;
 int verbose; // verbosity level

 // Error latch: this is set if the error handler is ever executed. It would be better to
 // use a try/catch block and throw, but that's not desired for certain environments, so
 // this is the alternative.
 mutable bool errorLatch;

 static errorfn_t errorHandler;
 static logfn_t logHandler;
};

} // namespace SPV

#endif // defined (use_cpp11)
#endif // SPIRVREMAPPER_H