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

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• Hash : 855d964b
  Author :
  Date : 2017-05-17T14:05:06
  

  Prefix user-defined names in GLSL output
  
  Now user-defined names are prefixed by _u in GLSL output in case name
  hashing is not on. Internal names such as names of temporary variables
  created in AST transformations are written out as such.
  
  This makes handling of internal function names and internal variable
  names consistent. It also removes the possibility of name conflicts
  between user-defined names and internal names in case name hashing is
  not on. In the same vein, it makes it safe to use GLSL reserved words
  that are not reserved in ESSL as variable names in case name hashing
  is not on.
  
  This also makes the GLSL output more consistent with how names are
  handled in HLSL output. Name hashing code is shared between
  VariableInfo and OutputGLSLBase to ensure names are handled
  consistently in both. The name that's used in the shader source for a
  given interface variable is written out to ShaderVariable::mappedName.
  
  An exception needs to be made for identifiers close to the length
  limit, since adding any prefix would take them over the limit. But
  they can be just written out as such, since we don't have any builtins
  or ANGLE internal variables that have as long names and could create a
  conflict.
  
  BUG=angleproject:2139
  BUG=angleproject:2038
  TEST=angle_unittests, angle_end2end_tests, WebGL conformance tests
  
  Change-Id: Id6ed052c4fab2d091227dc9a3668083053b67a38
  Reviewed-on: https://chromium-review.googlesource.com/507647
  Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
  Reviewed-by: Jamie Madill <jmadill@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/IntermNode.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;
  
  static const char *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.
  static const char *kUnhashedNamePrefix              = "_u";
  static const unsigned int kUnhashedNamePrefixLength = 2u;
  
  TString HashName(const TString &name, ShHashFunction64 hashFunction)
  {
      ASSERT(!name.empty());
      ASSERT(hashFunction);
      khronos_uint64_t number = (*hashFunction)(name.c_str(), name.length());
      TStringStream stream;
      stream << kHashedNamePrefix << std::hex << number;
      TString hashedName = stream.str();
      return hashedName;
  }
  
  }  // anonymous namespace
  
  TString HashName(const TName &name, ShHashFunction64 hashFunction, NameMap *nameMap)
  {
      if (name.getString().empty() || name.isInternal())
      {
          return name.getString();
      }
      if (hashFunction == nullptr)
      {
          if (name.getString().length() + kUnhashedNamePrefixLength > 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.getString();
          }
          return kUnhashedNamePrefix + name.getString();
      }
      if (nameMap)
      {
          NameMap::const_iterator it = nameMap->find(name.getString().c_str());
          if (it != nameMap->end())
              return it->second.c_str();
      }
      TString hashedName = HashName(name.getString(), hashFunction);
      if (nameMap)
      {
          (*nameMap)[name.getString().c_str()] = hashedName.c_str();
      }
      return hashedName;
  }
  
  }  // namespace sh
  

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