Hash :
b779b12c
Author :
Date :
2018-06-20T11:46:43
Add kEmptyImmutableString.
We can use this instead of ImmutableString("").
Bug: angleproject:2665
Change-Id: I8b3d5d3075838b9f2caa1627071202e48a5fdc83
Reviewed-on: https://chromium-review.googlesource.com/1108085
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Luc Ferron <lucferron@chromium.org>
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//
// 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
{
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 kEmptyImmutableString;
}
if (symbol->symbolType() == SymbolType::AngleInternal ||
symbol->symbolType() == SymbolType::BuiltIn)
{
return symbol->name();
}
return HashName(symbol->name(), hashFunction, nameMap);
}
} // namespace sh