SymbolTable.h

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//
// Copyright (C) 2002-2005 3Dlabs Inc. Ltd.
// Copyright (C) 2013 LunarG, Inc.
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#ifndef _SYMBOL_TABLE_INCLUDED_
#define _SYMBOL_TABLE_INCLUDED_

//
// Symbol table for parsing. Has these design characteristics:
//
// * Same symbol table can be used to compile many shaders, to preserve
// effort of creating and loading with the large numbers of built-in
// symbols.
//
// --> This requires a copy mechanism, so initial pools used to create
// the shared information can be popped. Done through "clone"
// methods.
//
// * Name mangling will be used to give each function a unique name
// so that symbol table lookups are never ambiguous. This allows
// a simpler symbol table structure.
//
// * Pushing and popping of scope, so symbol table will really be a stack
// of symbol tables. Searched from the top, with new inserts going into
// the top.
//
// * Constants: Compile time constant symbols will keep their values
// in the symbol table. The parser can substitute constants at parse
// time, including doing constant folding and constant propagation.
//
// * No temporaries: Temporaries made from operations (+, --, .xy, etc.)
// are tracked in the intermediate representation, not the symbol table.
//

#include "../Include/Common.h"
#include "../Include/intermediate.h"
#include "../Include/InfoSink.h"

namespace glslang {

//
// Symbol base class. (Can build functions or variables out of these...)
//

class TVariable;
class TFunction;
class TAnonMember;

class TSymbol {
public:
 POOL_ALLOCATOR_NEW_DELETE(GetThreadPoolAllocator())
 explicit TSymbol(const TString *n) : name(n), numExtensions(0), extensions(0), writable(true) { }
 virtual TSymbol* clone() const = 0;
 virtual ~TSymbol() { } // rely on all symbol owned memory coming from the pool

 virtual const TString& getName() const { return *name; }
 virtual void changeName(const TString* newName) { name = newName; }
 virtual void addPrefix(const char* prefix)
 {
 TString newName(prefix);
 newName.append(*name);
 changeName(NewPoolTString(newName.c_str()));
 }
 virtual const TString& getMangledName() const { return getName(); }
 virtual TFunction* getAsFunction() { return 0; }
 virtual const TFunction* getAsFunction() const { return 0; }
 virtual TVariable* getAsVariable() { return 0; }
 virtual const TVariable* getAsVariable() const { return 0; }
 virtual const TAnonMember* getAsAnonMember() const { return 0; }
 virtual const TType& getType() const = 0;
 virtual TType& getWritableType() = 0;
 virtual void setUniqueId(int id) { uniqueId = id; }
 virtual int getUniqueId() const { return uniqueId; }
 virtual void setExtensions(int num, const char* const exts[])
 {
 assert(extensions == 0);
 assert(num > 0);
 numExtensions = num;
 extensions = NewPoolObject(exts[0], num);
 for (int e = 0; e < num; ++e)
 extensions[e] = exts[e];
 }
 virtual int getNumExtensions() const { return numExtensions; }
 virtual const char** getExtensions() const { return extensions; }
 virtual void dump(TInfoSink &infoSink) const = 0;

 virtual bool isReadOnly() const { return ! writable; }
 virtual void makeReadOnly() { writable = false; }

protected:
 explicit TSymbol(const TSymbol&);
 TSymbol& operator=(const TSymbol&);

 const TString *name;
 unsigned int uniqueId; // For cross-scope comparing during code generation

 // For tracking what extensions must be present
 // (don't use if correct version/profile is present).
 int numExtensions;
 const char** extensions; // an array of pointers to existing constant char strings

 //
 // N.B.: Non-const functions that will be generally used should assert on this,
 // to avoid overwriting shared symbol-table information.
 //
 bool writable;
};

//
// Variable class, meaning a symbol that's not a function.
//
// There could be a separate class hierarchy for Constant variables;
// Only one of int, bool, or float, (or none) is correct for
// any particular use, but it's easy to do this way, and doesn't
// seem worth having separate classes, and "getConst" can't simply return
// different values for different types polymorphically, so this is
// just simple and pragmatic.
//
class TVariable : public TSymbol {
public:
 TVariable(const TString *name, const TType& t, bool uT = false )
 : TSymbol(name),
 userType(uT),
 constSubtree(nullptr),
 anonId(-1) { type.shallowCopy(t); }
 virtual TVariable* clone() const;
 virtual ~TVariable() { }

 virtual TVariable* getAsVariable() { return this; }
 virtual const TVariable* getAsVariable() const { return this; }
 virtual const TType& getType() const { return type; }
 virtual TType& getWritableType() { assert(writable); return type; }
 virtual bool isUserType() const { return userType; }
 virtual const TConstUnionArray& getConstArray() const { return constArray; }
 virtual TConstUnionArray& getWritableConstArray() { assert(writable); return constArray; }
 virtual void setConstArray(const TConstUnionArray& array) { constArray = array; }
 virtual void setConstSubtree(TIntermTyped* subtree) { constSubtree = subtree; }
 virtual TIntermTyped* getConstSubtree() const { return constSubtree; }
 virtual void setAnonId(int i) { anonId = i; }
 virtual int getAnonId() const { return anonId; }

 virtual void dump(TInfoSink &infoSink) const;

protected:
 explicit TVariable(const TVariable&);
 TVariable& operator=(const TVariable&);

 TType type;
 bool userType;
 // we are assuming that Pool Allocator will free the memory allocated to unionArray
 // when this object is destroyed

 // TODO: these two should be a union
 // A variable could be a compile-time constant, or a specialization
 // constant, or neither, but never both.
 TConstUnionArray constArray; // for compile-time constant value
 TIntermTyped* constSubtree; // for specialization constant computation
 int anonId; // the ID used for anonymous blocks: TODO: see if uniqueId could serve a dual purpose
};

//
// The function sub-class of symbols and the parser will need to
// share this definition of a function parameter.
//
struct TParameter {
 TString *name;
 TType* type;
 TIntermTyped* defaultValue;
 void copyParam(const TParameter& param)
 {
 if (param.name)
 name = NewPoolTString(param.name->c_str());
 else
 name = 0;
 type = param.type->clone();
 defaultValue = param.defaultValue;
 }
 TBuiltInVariable getDeclaredBuiltIn() const { return type->getQualifier().declaredBuiltIn; }
};

//
// The function sub-class of a symbol.
//
class TFunction : public TSymbol {
public:
 explicit TFunction(TOperator o) :
 TSymbol(0),
 op(o),
 defined(false), prototyped(false), implicitThis(false), illegalImplicitThis(false), defaultParamCount(0) { }
 TFunction(const TString *name, const TType& retType, TOperator tOp = EOpNull) :
 TSymbol(name),
 mangledName(*name + '('),
 op(tOp),
 defined(false), prototyped(false), implicitThis(false), illegalImplicitThis(false), defaultParamCount(0)
 {
 returnType.shallowCopy(retType);
 declaredBuiltIn = retType.getQualifier().builtIn;
 }
 virtual TFunction* clone() const override;
 virtual ~TFunction();

 virtual TFunction* getAsFunction() override { return this; }
 virtual const TFunction* getAsFunction() const override { return this; }

 // Install 'p' as the (non-'this') last parameter.
 // Non-'this' parameters are reflected in both the list of parameters and the
 // mangled name.
 virtual void addParameter(TParameter& p)
 {
 assert(writable);
 parameters.push_back(p);
 p.type->appendMangledName(mangledName);

 if (p.defaultValue != nullptr)
 defaultParamCount++;
 }

 // Install 'this' as the first parameter.
 // 'this' is reflected in the list of parameters, but not the mangled name.
 virtual void addThisParameter(TType& type, const char* name)
 {
 TParameter p = { NewPoolTString(name), new TType, nullptr };
 p.type->shallowCopy(type);
 parameters.insert(parameters.begin(), p);
 }

 virtual void addPrefix(const char* prefix) override
 {
 TSymbol::addPrefix(prefix);
 mangledName.insert(0, prefix);
 }

 virtual void removePrefix(const TString& prefix)
 {
 assert(mangledName.compare(0, prefix.size(), prefix) == 0);
 mangledName.erase(0, prefix.size());
 }

 virtual const TString& getMangledName() const override { return mangledName; }
 virtual const TType& getType() const override { return returnType; }
 virtual TBuiltInVariable getDeclaredBuiltInType() const { return declaredBuiltIn; }
 virtual TType& getWritableType() override { return returnType; }
 virtual void relateToOperator(TOperator o) { assert(writable); op = o; }
 virtual TOperator getBuiltInOp() const { return op; }
 virtual void setDefined() { assert(writable); defined = true; }
 virtual bool isDefined() const { return defined; }
 virtual void setPrototyped() { assert(writable); prototyped = true; }
 virtual bool isPrototyped() const { return prototyped; }
 virtual void setImplicitThis() { assert(writable); implicitThis = true; }
 virtual bool hasImplicitThis() const { return implicitThis; }
 virtual void setIllegalImplicitThis() { assert(writable); illegalImplicitThis = true; }
 virtual bool hasIllegalImplicitThis() const { return illegalImplicitThis; }

 // Return total number of parameters
 virtual int getParamCount() const { return static_cast<int>(parameters.size()); }
 // Return number of parameters with default values.
 virtual int getDefaultParamCount() const { return defaultParamCount; }
 // Return number of fixed parameters (without default values)
 virtual int getFixedParamCount() const { return getParamCount() - getDefaultParamCount(); }

 virtual TParameter& operator[](int i) { assert(writable); return parameters[i]; }
 virtual const TParameter& operator[](int i) const { return parameters[i]; }

 virtual void dump(TInfoSink &infoSink) const override;

protected:
 explicit TFunction(const TFunction&);
 TFunction& operator=(const TFunction&);

 typedef TVector<TParameter> TParamList;
 TParamList parameters;
 TType returnType;
 TBuiltInVariable declaredBuiltIn;

 TString mangledName;
 TOperator op;
 bool defined;
 bool prototyped;
 bool implicitThis; // True if this function is allowed to see all members of 'this'
 bool illegalImplicitThis; // True if this function is not supposed to have access to dynamic members of 'this',
 // even if it finds member variables in the symbol table.
 // This is important for a static member function that has member variables in scope,
 // but is not allowed to use them, or see hidden symbols instead.
 int defaultParamCount;
};

//
// Members of anonymous blocks are a kind of TSymbol. They are not hidden in
// the symbol table behind a container; rather they are visible and point to
// their anonymous container. (The anonymous container is found through the
// member, not the other way around.)
//
class TAnonMember : public TSymbol {
public:
 TAnonMember(const TString* n, unsigned int m, const TVariable& a, int an) : TSymbol(n), anonContainer(a), memberNumber(m), anonId(an) { }
 virtual TAnonMember* clone() const;
 virtual ~TAnonMember() { }

 virtual const TAnonMember* getAsAnonMember() const { return this; }
 virtual const TVariable& getAnonContainer() const { return anonContainer; }
 virtual unsigned int getMemberNumber() const { return memberNumber; }

 virtual const TType& getType() const
 {
 const TTypeList& types = *anonContainer.getType().getStruct();
 return *types[memberNumber].type;
 }

 virtual TType& getWritableType()
 {
 assert(writable);
 const TTypeList& types = *anonContainer.getType().getStruct();
 return *types[memberNumber].type;
 }

 virtual int getAnonId() const { return anonId; }
 virtual void dump(TInfoSink &infoSink) const;

protected:
 explicit TAnonMember(const TAnonMember&);
 TAnonMember& operator=(const TAnonMember&);

 const TVariable& anonContainer;
 unsigned int memberNumber;
 int anonId;
};

class TSymbolTableLevel {
public:
 POOL_ALLOCATOR_NEW_DELETE(GetThreadPoolAllocator())
 TSymbolTableLevel() : defaultPrecision(0), anonId(0), thisLevel(false) { }
 ~TSymbolTableLevel();

 bool insert(TSymbol& symbol, bool separateNameSpaces)
 {
 //
 // returning true means symbol was added to the table with no semantic errors
 //
 const TString& name = symbol.getName();
 if (name == "") {
 symbol.getAsVariable()->setAnonId(anonId++);
 // An empty name means an anonymous container, exposing its members to the external scope.
 // Give it a name and insert its members in the symbol table, pointing to the container.
 char buf[20];
 snprintf(buf, 20, "%s%d", AnonymousPrefix, symbol.getAsVariable()->getAnonId());
 symbol.changeName(NewPoolTString(buf));

 return insertAnonymousMembers(symbol, 0);
 } else {
 // Check for redefinition errors:
 // - STL itself will tell us if there is a direct name collision, with name mangling, at this level
 // - additionally, check for function-redefining-variable name collisions
 const TString& insertName = symbol.getMangledName();
 if (symbol.getAsFunction()) {
 // make sure there isn't a variable of this name
 if (! separateNameSpaces && level.find(name) != level.end())
 return false;

 // insert, and whatever happens is okay
 level.insert(tLevelPair(insertName, &symbol));

 return true;
 } else
 return level.insert(tLevelPair(insertName, &symbol)).second;
 }
 }

 // Add more members to an already inserted aggregate object
 bool amend(TSymbol& symbol, int firstNewMember)
 {
 // See insert() for comments on basic explanation of insert.
 // This operates similarly, but more simply.
 // Only supporting amend of anonymous blocks so far.
 if (IsAnonymous(symbol.getName()))
 return insertAnonymousMembers(symbol, firstNewMember);
 else
 return false;
 }

 bool insertAnonymousMembers(TSymbol& symbol, int firstMember)
 {
 const TTypeList& types = *symbol.getAsVariable()->getType().getStruct();
 for (unsigned int m = firstMember; m < types.size(); ++m) {
 TAnonMember* member = new TAnonMember(&types[m].type->getFieldName(), m, *symbol.getAsVariable(), symbol.getAsVariable()->getAnonId());
 if (! level.insert(tLevelPair(member->getMangledName(), member)).second)
 return false;
 }

 return true;
 }

 TSymbol* find(const TString& name) const
 {
 tLevel::const_iterator it = level.find(name);
 if (it == level.end())
 return 0;
 else
 return (*it).second;
 }

 void findFunctionNameList(const TString& name, TVector<const TFunction*>& list)
 {
 size_t parenAt = name.find_first_of('(');
 TString base(name, 0, parenAt + 1);

 tLevel::const_iterator begin = level.lower_bound(base);
 base[parenAt] = ')'; // assume ')' is lexically after '('
 tLevel::const_iterator end = level.upper_bound(base);
 for (tLevel::const_iterator it = begin; it != end; ++it)
 list.push_back(it->second->getAsFunction());
 }

 // See if there is already a function in the table having the given non-function-style name.
 bool hasFunctionName(const TString& name) const
 {
 tLevel::const_iterator candidate = level.lower_bound(name);
 if (candidate != level.end()) {
 const TString& candidateName = (*candidate).first;
 TString::size_type parenAt = candidateName.find_first_of('(');
 if (parenAt != candidateName.npos && candidateName.compare(0, parenAt, name) == 0)

 return true;
 }

 return false;
 }

 // See if there is a variable at this level having the given non-function-style name.
 // Return true if name is found, and set variable to true if the name was a variable.
 bool findFunctionVariableName(const TString& name, bool& variable) const
 {
 tLevel::const_iterator candidate = level.lower_bound(name);
 if (candidate != level.end()) {
 const TString& candidateName = (*candidate).first;
 TString::size_type parenAt = candidateName.find_first_of('(');
 if (parenAt == candidateName.npos) {
 // not a mangled name
 if (candidateName == name) {
 // found a variable name match
 variable = true;
 return true;
 }
 } else {
 // a mangled name
 if (candidateName.compare(0, parenAt, name) == 0) {
 // found a function name match
 variable = false;
 return true;
 }
 }
 }

 return false;
 }

 // Use this to do a lazy 'push' of precision defaults the first time
 // a precision statement is seen in a new scope. Leave it at 0 for
 // when no push was needed. Thus, it is not the current defaults,
 // it is what to restore the defaults to when popping a level.
 void setPreviousDefaultPrecisions(const TPrecisionQualifier *p)
 {
 // can call multiple times at one scope, will only latch on first call,
 // as we're tracking the previous scope's values, not the current values
 if (defaultPrecision != 0)
 return;

 defaultPrecision = new TPrecisionQualifier[EbtNumTypes];
 for (int t = 0; t < EbtNumTypes; ++t)
 defaultPrecision[t] = p[t];
 }

 void getPreviousDefaultPrecisions(TPrecisionQualifier *p)
 {
 // can be called for table level pops that didn't set the
 // defaults
 if (defaultPrecision == 0 || p == 0)
 return;

 for (int t = 0; t < EbtNumTypes; ++t)
 p[t] = defaultPrecision[t];
 }

 void relateToOperator(const char* name, TOperator op);
 void setFunctionExtensions(const char* name, int num, const char* const extensions[]);
 void dump(TInfoSink &infoSink) const;
 TSymbolTableLevel* clone() const;
 void readOnly();

 void setThisLevel() { thisLevel = true; }
 bool isThisLevel() const { return thisLevel; }

protected:
 explicit TSymbolTableLevel(TSymbolTableLevel&);
 TSymbolTableLevel& operator=(TSymbolTableLevel&);

 typedef std::map<TString, TSymbol*, std::less<TString>, pool_allocator<std::pair<const TString, TSymbol*> > > tLevel;
 typedef const tLevel::value_type tLevelPair;
 typedef std::pair<tLevel::iterator, bool> tInsertResult;

 tLevel level; // named mappings
 TPrecisionQualifier *defaultPrecision;
 int anonId;
 bool thisLevel; // True if this level of the symbol table is a structure scope containing member function
 // that are supposed to see anonymous access to member variables.
};

class TSymbolTable {
public:
 TSymbolTable() : uniqueId(0), noBuiltInRedeclarations(false), separateNameSpaces(false), adoptedLevels(0)
 {
 //
 // This symbol table cannot be used until push() is called.
 //
 }
 ~TSymbolTable()
 {
 // this can be called explicitly; safest to code it so it can be called multiple times

 // don't deallocate levels passed in from elsewhere
 while (table.size() > adoptedLevels)
 pop(0);
 }

 void adoptLevels(TSymbolTable& symTable)
 {
 for (unsigned int level = 0; level < symTable.table.size(); ++level) {
 table.push_back(symTable.table[level]);
 ++adoptedLevels;
 }
 uniqueId = symTable.uniqueId;
 noBuiltInRedeclarations = symTable.noBuiltInRedeclarations;
 separateNameSpaces = symTable.separateNameSpaces;
 }

 //
 // While level adopting is generic, the methods below enact a the following
 // convention for levels:
 // 0: common built-ins shared across all stages, all compiles, only one copy for all symbol tables
 // 1: per-stage built-ins, shared across all compiles, but a different copy per stage
 // 2: built-ins specific to a compile, like resources that are context-dependent, or redeclared built-ins
 // 3: user-shader globals
 //
protected:
 static const int globalLevel = 3;
 bool isSharedLevel(int level) { return level <= 1; } // exclude all per-compile levels
 bool isBuiltInLevel(int level) { return level <= 2; } // exclude user globals
 bool isGlobalLevel(int level) { return level <= globalLevel; } // include user globals
public:
 bool isEmpty() { return table.size() == 0; }
 bool atBuiltInLevel() { return isBuiltInLevel(currentLevel()); }
 bool atGlobalLevel() { return isGlobalLevel(currentLevel()); }

 void setNoBuiltInRedeclarations() { noBuiltInRedeclarations = true; }
 void setSeparateNameSpaces() { separateNameSpaces = true; }

 void push()
 {
 table.push_back(new TSymbolTableLevel);
 }

 // Make a new symbol-table level to represent the scope introduced by a structure
 // containing member functions, such that the member functions can find anonymous
 // references to member variables.
 //
 // 'thisSymbol' should have a name of "" to trigger anonymous structure-member
 // symbol finds.
 void pushThis(TSymbol& thisSymbol)
 {
 assert(thisSymbol.getName().size() == 0);
 table.push_back(new TSymbolTableLevel);
 table.back()->setThisLevel();
 insert(thisSymbol);
 }

 void pop(TPrecisionQualifier *p)
 {
 table[currentLevel()]->getPreviousDefaultPrecisions(p);
 delete table.back();
 table.pop_back();
 }

 //
 // Insert a visible symbol into the symbol table so it can
 // be found later by name.
 //
 // Returns false if the was a name collision.
 //
 bool insert(TSymbol& symbol)
 {
 symbol.setUniqueId(++uniqueId);

 // make sure there isn't a function of this variable name
 if (! separateNameSpaces && ! symbol.getAsFunction() && table[currentLevel()]->hasFunctionName(symbol.getName()))
 return false;

 // check for not overloading or redefining a built-in function
 if (noBuiltInRedeclarations) {
 if (atGlobalLevel() && currentLevel() > 0) {
 if (table[0]->hasFunctionName(symbol.getName()))
 return false;
 if (currentLevel() > 1 && table[1]->hasFunctionName(symbol.getName()))
 return false;
 }
 }

 return table[currentLevel()]->insert(symbol, separateNameSpaces);
 }

 // Add more members to an already inserted aggregate object
 bool amend(TSymbol& symbol, int firstNewMember)
 {
 // See insert() for comments on basic explanation of insert.
 // This operates similarly, but more simply.
 return table[currentLevel()]->amend(symbol, firstNewMember);
 }

 //
 // To allocate an internal temporary, which will need to be uniquely
 // identified by the consumer of the AST, but never need to
 // found by doing a symbol table search by name, hence allowed an
 // arbitrary name in the symbol with no worry of collision.
 //
 void makeInternalVariable(TSymbol& symbol)
 {
 symbol.setUniqueId(++uniqueId);
 }

 //
 // Copy a variable or anonymous member's structure from a shared level so that
 // it can be added (soon after return) to the symbol table where it can be
 // modified without impacting other users of the shared table.
 //
 TSymbol* copyUpDeferredInsert(TSymbol* shared)
 {
 if (shared->getAsVariable()) {
 TSymbol* copy = shared->clone();
 copy->setUniqueId(shared->getUniqueId());
 return copy;
 } else {
 const TAnonMember* anon = shared->getAsAnonMember();
 assert(anon);
 TVariable* container = anon->getAnonContainer().clone();
 container->changeName(NewPoolTString(""));
 container->setUniqueId(anon->getAnonContainer().getUniqueId());
 return container;
 }
 }

 TSymbol* copyUp(TSymbol* shared)
 {
 TSymbol* copy = copyUpDeferredInsert(shared);
 table[globalLevel]->insert(*copy, separateNameSpaces);
 if (shared->getAsVariable())
 return copy;
 else {
 // return the copy of the anonymous member
 return table[globalLevel]->find(shared->getName());
 }
 }

 // Normal find of a symbol, that can optionally say whether the symbol was found
 // at a built-in level or the current top-scope level.
 TSymbol* find(const TString& name, bool* builtIn = 0, bool* currentScope = 0, int* thisDepthP = 0)
 {
 int level = currentLevel();
 TSymbol* symbol;
 int thisDepth = 0;
 do {
 if (table[level]->isThisLevel())
 ++thisDepth;
 symbol = table[level]->find(name);
 --level;
 } while (symbol == nullptr && level >= 0);
 level++;
 if (builtIn)
 *builtIn = isBuiltInLevel(level);
 if (currentScope)
 *currentScope = isGlobalLevel(currentLevel()) || level == currentLevel(); // consider shared levels as "current scope" WRT user globals
 if (thisDepthP != nullptr) {
 if (! table[level]->isThisLevel())
 thisDepth = 0;
 *thisDepthP = thisDepth;
 }

 return symbol;
 }

 // Find of a symbol that returns how many layers deep of nested
 // structures-with-member-functions ('this' scopes) deep the symbol was
 // found in.
 TSymbol* find(const TString& name, int& thisDepth)
 {
 int level = currentLevel();
 TSymbol* symbol;
 thisDepth = 0;
 do {
 if (table[level]->isThisLevel())
 ++thisDepth;
 symbol = table[level]->find(name);
 --level;
 } while (symbol == 0 && level >= 0);

 if (! table[level + 1]->isThisLevel())
 thisDepth = 0;

 return symbol;
 }

 bool isFunctionNameVariable(const TString& name) const
 {
 if (separateNameSpaces)
 return false;

 int level = currentLevel();
 do {
 bool variable;
 bool found = table[level]->findFunctionVariableName(name, variable);
 if (found)
 return variable;
 --level;
 } while (level >= 0);

 return false;
 }

 void findFunctionNameList(const TString& name, TVector<const TFunction*>& list, bool& builtIn)
 {
 // For user levels, return the set found in the first scope with a match
 builtIn = false;
 int level = currentLevel();
 do {
 table[level]->findFunctionNameList(name, list);
 --level;
 } while (list.empty() && level >= globalLevel);

 if (! list.empty())
 return;

 // Gather across all built-in levels; they don't hide each other
 builtIn = true;
 do {
 table[level]->findFunctionNameList(name, list);
 --level;
 } while (level >= 0);
 }

 void relateToOperator(const char* name, TOperator op)
 {
 for (unsigned int level = 0; level < table.size(); ++level)
 table[level]->relateToOperator(name, op);
 }

 void setFunctionExtensions(const char* name, int num, const char* const extensions[])
 {
 for (unsigned int level = 0; level < table.size(); ++level)
 table[level]->setFunctionExtensions(name, num, extensions);
 }

 void setVariableExtensions(const char* name, int num, const char* const extensions[])
 {
 TSymbol* symbol = find(TString(name));
 if (symbol)
 symbol->setExtensions(num, extensions);
 }

 int getMaxSymbolId() { return uniqueId; }
 void dump(TInfoSink &infoSink) const;
 void copyTable(const TSymbolTable& copyOf);

 void setPreviousDefaultPrecisions(TPrecisionQualifier *p) { table[currentLevel()]->setPreviousDefaultPrecisions(p); }

 void readOnly()
 {
 for (unsigned int level = 0; level < table.size(); ++level)
 table[level]->readOnly();
 }

protected:
 TSymbolTable(TSymbolTable&);
 TSymbolTable& operator=(TSymbolTableLevel&);

 int currentLevel() const { return static_cast<int>(table.size()) - 1; }

 std::vector<TSymbolTableLevel*> table;
 int uniqueId; // for unique identification in code generation
 bool noBuiltInRedeclarations;
 bool separateNameSpaces;
 unsigned int adoptedLevels;
};

} // end namespace glslang

#endif // _SYMBOL_TABLE_INCLUDED_