tor-browser

SymbolTable.h (13489B)

---

//
// Copyright 2002 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//

#ifndef COMPILER_TRANSLATOR_SYMBOLTABLE_H_
#define COMPILER_TRANSLATOR_SYMBOLTABLE_H_

//
// 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.
//
// * 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 <limits>
#include <memory>
#include <set>

#include "common/angleutils.h"
#include "compiler/translator/ExtensionBehavior.h"
#include "compiler/translator/ImmutableString.h"
#include "compiler/translator/InfoSink.h"
#include "compiler/translator/IntermNode.h"
#include "compiler/translator/Symbol.h"
#include "compiler/translator/SymbolTable_autogen.h"

enum class Shader : uint8_t
{
   ALL,
   FRAGMENT,             // GL_FRAGMENT_SHADER
   VERTEX,               // GL_VERTEX_SHADER
   COMPUTE,              // GL_COMPUTE_SHADER
   GEOMETRY,             // GL_GEOMETRY_SHADER
   GEOMETRY_EXT,         // GL_GEOMETRY_SHADER_EXT
   TESS_CONTROL_EXT,     // GL_TESS_CONTROL_SHADER_EXT
   TESS_EVALUATION_EXT,  // GL_TESS_EVALUATION_SHADER_EXT
   NOT_COMPUTE
};

namespace sh
{

struct UnmangledBuiltIn
{
   constexpr UnmangledBuiltIn(TExtension extension) : extension(extension) {}

   TExtension extension;
};

using VarPointer        = TSymbol *(TSymbolTableBase::*);
using ValidateExtension = int ShBuiltInResources::*;

enum class Spec : uint8_t
{
   GLSL,
   ESSL
};

constexpr uint16_t kESSL1Only = 100;
// Some built-ins from backend shader languages are made available internally to ESSL for use in
// tree transformations.  This (invalid) shader version is used to select those built-ins.  This
// value needs to be larger than all other shader versions.
constexpr uint16_t kESSLInternalBackendBuiltIns = 0x3FFF;

// The version assigned to |kESSLInternalBackendBuiltIns| should be good until OpenGL 20.0!
static_assert(kESSLInternalBackendBuiltIns > 2000,
             "Accidentally exposing internal backend built-ins in OpenGL");

static_assert(offsetof(ShBuiltInResources, OES_standard_derivatives) != 0,
             "Update SymbolTable extension logic");

#define EXT_INDEX(Ext) (offsetof(ShBuiltInResources, Ext) / sizeof(int))

class SymbolRule
{
 public:
   const TSymbol *get(ShShaderSpec shaderSpec,
                      int shaderVersion,
                      sh::GLenum shaderType,
                      const ShBuiltInResources &resources,
                      const TSymbolTableBase &symbolTable) const;

   template <Spec spec, int version, Shader shaders, size_t extensionIndex, typename T>
   constexpr static SymbolRule Get(T value);

 private:
   constexpr SymbolRule(Spec spec,
                        int version,
                        Shader shaders,
                        size_t extensionIndex,
                        const TSymbol *symbol);

   constexpr SymbolRule(Spec spec,
                        int version,
                        Shader shaders,
                        size_t extensionIndex,
                        VarPointer resourceVar);

   union SymbolOrVar
   {
       constexpr SymbolOrVar(const TSymbol *symbolIn) : symbol(symbolIn) {}
       constexpr SymbolOrVar(VarPointer varIn) : var(varIn) {}

       const TSymbol *symbol;
       VarPointer var;
   };

   uint16_t mIsDesktop : 1;
   uint16_t mIsVar : 1;
   uint16_t mVersion : 14;
   uint8_t mShaders;
   uint8_t mExtensionIndex;
   SymbolOrVar mSymbolOrVar;
};

constexpr SymbolRule::SymbolRule(Spec spec,
                                int version,
                                Shader shaders,
                                size_t extensionIndex,
                                const TSymbol *symbol)
   : mIsDesktop(spec == Spec::GLSL ? 1u : 0u),
     mIsVar(0u),
     mVersion(static_cast<uint16_t>(version)),
     mShaders(static_cast<uint8_t>(shaders)),
     mExtensionIndex(extensionIndex),
     mSymbolOrVar(symbol)
{}

constexpr SymbolRule::SymbolRule(Spec spec,
                                int version,
                                Shader shaders,
                                size_t extensionIndex,
                                VarPointer resourceVar)
   : mIsDesktop(spec == Spec::GLSL ? 1u : 0u),
     mIsVar(1u),
     mVersion(static_cast<uint16_t>(version)),
     mShaders(static_cast<uint8_t>(shaders)),
     mExtensionIndex(extensionIndex),
     mSymbolOrVar(resourceVar)
{}

template <Spec spec, int version, Shader shaders, size_t extensionIndex, typename T>
// static
constexpr SymbolRule SymbolRule::Get(T value)
{
   static_assert(version < 0x4000u, "version OOR");
   static_assert(static_cast<uint8_t>(shaders) < 0xFFu, "shaders OOR");
   static_assert(static_cast<uint8_t>(extensionIndex) < 0xFF, "extensionIndex OOR");
   return SymbolRule(spec, version, shaders, extensionIndex, value);
}

const TSymbol *FindMangledBuiltIn(ShShaderSpec shaderSpec,
                                 int shaderVersion,
                                 sh::GLenum shaderType,
                                 const ShBuiltInResources &resources,
                                 const TSymbolTableBase &symbolTable,
                                 const SymbolRule *rules,
                                 uint16_t startIndex,
                                 uint16_t endIndex);

class UnmangledEntry
{
 public:
   template <size_t ESSLExtCount>
   constexpr UnmangledEntry(const char *name,
                            const std::array<TExtension, ESSLExtCount> &esslExtensions,
                            TExtension glslExtension,
                            int esslVersion,
                            int glslVersion,
                            Shader shaderType);

   bool matches(const ImmutableString &name,
                ShShaderSpec shaderSpec,
                int shaderVersion,
                sh::GLenum shaderType,
                const TExtensionBehavior &extensions) const;

 private:
   const char *mName;
   std::array<TExtension, 2u> mESSLExtensions;
   TExtension mGLSLExtension;
   uint8_t mShaderType;
   uint16_t mESSLVersion;
   uint16_t mGLSLVersion;
};

template <size_t ESSLExtCount>
constexpr UnmangledEntry::UnmangledEntry(const char *name,
                                        const std::array<TExtension, ESSLExtCount> &esslExtensions,
                                        TExtension glslExtension,
                                        int esslVersion,
                                        int glslVersion,
                                        Shader shaderType)
   : mName(name),
     mESSLExtensions{(ESSLExtCount >= 1) ? esslExtensions[0] : TExtension::UNDEFINED,
                     (ESSLExtCount >= 2) ? esslExtensions[1] : TExtension::UNDEFINED},
     mGLSLExtension(glslExtension),
     mShaderType(static_cast<uint8_t>(shaderType)),
     mESSLVersion(esslVersion < 0 ? std::numeric_limits<uint16_t>::max()
                                  : static_cast<uint16_t>(esslVersion)),
     mGLSLVersion(glslVersion < 0 ? std::numeric_limits<uint16_t>::max()
                                  : static_cast<uint16_t>(glslVersion))
{}

class TSymbolTable : angle::NonCopyable, TSymbolTableBase
{
 public:
   TSymbolTable();
   // To start using the symbol table after construction:
   // * initializeBuiltIns() needs to be called.
   // * push() needs to be called to push the global level.

   ~TSymbolTable();

   bool isEmpty() const;
   bool atGlobalLevel() const;

   void push();
   void pop();

   // Declare a non-function symbol at the current scope. Return true in case the declaration was
   // successful, and false if the declaration failed due to redefinition.
   bool declare(TSymbol *symbol);

   // Only used to declare internal variables.
   bool declareInternal(TSymbol *symbol);

   // Functions are always declared at global scope.
   void declareUserDefinedFunction(TFunction *function, bool insertUnmangledName);

   // These return the TFunction pointer to keep using to refer to this function.
   const TFunction *markFunctionHasPrototypeDeclaration(const ImmutableString &mangledName,
                                                        bool *hadPrototypeDeclarationOut) const;
   const TFunction *setFunctionParameterNamesFromDefinition(const TFunction *function,
                                                            bool *wasDefinedOut) const;

   // Return false if the gl_in array size has already been initialized with a mismatching value.
   bool setGlInArraySize(unsigned int inputArraySize);
   TVariable *getGlInVariableWithArraySize() const;

   const TVariable *gl_FragData() const;
   const TVariable *gl_SecondaryFragDataEXT() const;

   void markStaticRead(const TVariable &variable);
   void markStaticWrite(const TVariable &variable);

   // Note: Should not call this for constant variables.
   bool isStaticallyUsed(const TVariable &variable) const;

   // find() is guaranteed not to retain a reference to the ImmutableString, so an ImmutableString
   // with a reference to a short-lived char * is fine to pass here.
   const TSymbol *find(const ImmutableString &name, int shaderVersion) const;

   const TSymbol *findUserDefined(const ImmutableString &name) const;

   TFunction *findUserDefinedFunction(const ImmutableString &name) const;

   const TSymbol *findGlobal(const ImmutableString &name) const;
   const TSymbol *findGlobalWithConversion(const std::vector<ImmutableString> &names) const;

   const TSymbol *findBuiltIn(const ImmutableString &name, int shaderVersion) const;
   const TSymbol *findBuiltInWithConversion(const std::vector<ImmutableString> &names,
                                            int shaderVersion) const;

   void setDefaultPrecision(TBasicType type, TPrecision prec);

   // Searches down the precisionStack for a precision qualifier
   // for the specified TBasicType
   TPrecision getDefaultPrecision(TBasicType type) const;

   // This records invariant varyings declared through "invariant varying_name;".
   void addInvariantVarying(const TVariable &variable);

   // If this returns false, the varying could still be invariant if it is set as invariant during
   // the varying variable declaration - this piece of information is stored in the variable's
   // type, not here.
   bool isVaryingInvariant(const TVariable &variable) const;

   void setGlobalInvariant(bool invariant);

   const TSymbolUniqueId nextUniqueId() { return TSymbolUniqueId(this); }

   // Gets the built-in accessible by a shader with the specified version, if any.
   bool isUnmangledBuiltInName(const ImmutableString &name,
                               int shaderVersion,
                               const TExtensionBehavior &extensions) const;

   void initializeBuiltIns(sh::GLenum type,
                           ShShaderSpec spec,
                           const ShBuiltInResources &resources);
   void clearCompilationResults();

   ShShaderSpec getShaderSpec() const { return mShaderSpec; }

 private:
   friend class TSymbolUniqueId;

   struct VariableMetadata
   {
       VariableMetadata();
       bool staticRead;
       bool staticWrite;
       bool invariant;
   };

   int nextUniqueIdValue();

   class TSymbolTableLevel;

   void initSamplerDefaultPrecision(TBasicType samplerType);

   void initializeBuiltInVariables(sh::GLenum shaderType,
                                   ShShaderSpec spec,
                                   const ShBuiltInResources &resources);

   VariableMetadata *getOrCreateVariableMetadata(const TVariable &variable);

   std::vector<std::unique_ptr<TSymbolTableLevel>> mTable;

   // There's one precision stack level for predefined precisions and then one level for each scope
   // in table.
   typedef TMap<TBasicType, TPrecision> PrecisionStackLevel;
   std::vector<std::unique_ptr<PrecisionStackLevel>> mPrecisionStack;

   bool mGlobalInvariant;

   int mUniqueIdCounter;

   static const int kLastBuiltInId;

   sh::GLenum mShaderType;
   ShShaderSpec mShaderSpec;
   ShBuiltInResources mResources;

   // Indexed by unique id. Map instead of vector since the variables are fairly sparse.
   std::map<int, VariableMetadata> mVariableMetadata;

   // Store gl_in variable with its array size once the array size can be determined. The array
   // size can also be checked against latter input primitive type declaration.
   TVariable *mGlInVariableWithArraySize;
};

}  // namespace sh

#endif  // COMPILER_TRANSLATOR_SYMBOLTABLE_H_