kc3-lang/angle/src/compiler/translator/HashNames.cpp

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• Hash : fbb1c792
  Author :
  Date : 2018-01-19T16:26:59
  

  Store symbol names as a ImmutableString
  
  This will enable compile-time initialization of built-in symbols as
  well as reducing copying strings.
  
  Most of the code that deals with names is changed to use
  ImmutableString where it makes sense to avoid conversions.
  
  The lexer/parser now allocate const char pointers into pool memory
  instead of allocating TStrings. These are then converted to
  ImmutableString upon entering TParseContext.
  
  BUG=angleproject:2267
  TEST=angle_unittests, angle_end2end_tests
  
  Change-Id: I244d6271ea1ecf7150d4f89dfa388a7745a1150c
  Reviewed-on: https://chromium-review.googlesource.com/881561
  Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
  Reviewed-by: Corentin Wallez <cwallez@chromium.org>
  

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• src/compiler/translator/HashNames.cpp

• //
  // Copyright (c) 2017 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.
  //
  
  #include "compiler/translator/HashNames.h"
  
  #include "compiler/translator/ImmutableString.h"
  #include "compiler/translator/ImmutableStringBuilder.h"
  #include "compiler/translator/IntermNode.h"
  #include "compiler/translator/Symbol.h"
  
  namespace sh
  {
  
  namespace
  {
  
  // GLSL ES 3.00.6 section 3.9: the maximum length of an identifier is 1024 characters.
  static const unsigned int kESSLMaxIdentifierLength = 1024u;
  
  constexpr const ImmutableString kHashedNamePrefix("webgl_");
  
  // Can't prefix with just _ because then we might introduce a double underscore, which is not safe
  // in GLSL (ESSL 3.00.6 section 3.8: All identifiers containing a double underscore are reserved for
  // use by the underlying implementation). u is short for user-defined.
  constexpr const ImmutableString kUnhashedNamePrefix("_u");
  
  ImmutableString HashName(const ImmutableString &name, ShHashFunction64 hashFunction)
  {
      ASSERT(!name.empty());
      ASSERT(hashFunction);
      khronos_uint64_t number = (*hashFunction)(name.data(), name.length());
  
      // Build the hashed name in place.
      static const unsigned int kHexStrMaxLength = sizeof(number) * 2;
      static const size_t kHashedNameMaxLength   = kHashedNamePrefix.length() + kHexStrMaxLength;
  
      ImmutableStringBuilder hashedName(kHashedNameMaxLength);
      hashedName << kHashedNamePrefix;
  
      hashedName.appendHex(number);
  
      return hashedName;
  }
  
  }  // anonymous namespace
  
  ImmutableString HashName(const ImmutableString &name,
                           ShHashFunction64 hashFunction,
                           NameMap *nameMap)
  {
      if (hashFunction == nullptr)
      {
          if (name.length() + kUnhashedNamePrefix.length() > kESSLMaxIdentifierLength)
          {
              // If the identifier length is already close to the limit, we can't prefix it. This is
              // not a problem since there are no builtins or ANGLE's internal variables that would
              // have as long names and could conflict.
              return name;
          }
          ImmutableStringBuilder prefixedName(kUnhashedNamePrefix.length() + name.length());
          prefixedName << kUnhashedNamePrefix << name;
          return prefixedName;
      }
      if (nameMap)
      {
          NameMap::const_iterator it = nameMap->find(name.data());
          if (it != nameMap->end())
          {
              // TODO(oetuaho): Would be nice if we didn't need to allocate a string here.
              return ImmutableString(it->second);
          }
      }
      ImmutableString hashedName = HashName(name, hashFunction);
      if (nameMap)
      {
          (*nameMap)[name.data()] = hashedName.data();
      }
      return hashedName;
  }
  
  ImmutableString HashName(const TSymbol *symbol, ShHashFunction64 hashFunction, NameMap *nameMap)
  {
      if (symbol->symbolType() == SymbolType::Empty)
      {
          return ImmutableString("");
      }
      if (symbol->symbolType() == SymbolType::AngleInternal ||
          symbol->symbolType() == SymbolType::BuiltIn)
      {
          return symbol->name();
      }
      return HashName(symbol->name(), hashFunction, nameMap);
  }
  
  }  // namespace sh
  

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