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

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  • Author : Mohan Maiya
    Date : 2021-02-24 09:49:42
    Hash : 550f2a3e
    Message : Vulkan: Shader support for EXT_shader_framebuffer_fetch_non_coherent Translator can accept gl_LastFragData and 'inout' variable to gain access to framebuffer attachment data. The Vulkan translator replaces it with the SubpassInput type variable. Note that this works only for the noncoherent version of the extension. Bug: angleproject:5454 Test: *EXTShaderFramebufferFetchNoncoherent*.* Change-Id: I392f84ee3ad3eb9fbd09d0b7ff83731a9a3f33f6 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2598060 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Mohan Maiya <m.maiya@samsung.com>

  • src/compiler/translator/HashNames.cpp
  • //
    // Copyright 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_");
    
    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;
    }
    
    void AddToNameMapIfNotMapped(const ImmutableString &name,
                                 const ImmutableString &hashedName,
                                 NameMap *nameMap)
    {
        if (nameMap)
        {
            NameMap::const_iterator it = nameMap->find(name.data());
            if (it != nameMap->end())
            {
                // (How bout returning?)
                return;
            }
            (*nameMap)[name.data()] = hashedName.data();
        }
    }
    
    }  // anonymous namespace
    
    ImmutableString HashName(const ImmutableString &name,
                             ShHashFunction64 hashFunction,
                             NameMap *nameMap)
    {
        const ImmutableString kUnhashedNamePrefix(kUserDefinedNamePrefix);
    
        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;
            }
            if (name == "gl_ClipDistance" || name == "gl_CullDistance" || name == "gl_LastFragData")
            {
                // NOTE(hqle): When gl_ClipDistance is re-declared, it will become an UserDefined
                // symbol. Normally, UserDefined symbols will have "_u" prefix added to their names by
                // ANGLE. However, gl_ClipDistance is an exception. If we add "_u" to its name, the
                // backend won't be able to handle it properly. So for gl_ClipDistance, we won't add
                // "_u" prefix, instead we return it original name.
                //
                // The other way is treating gl_ClipDistance as an AngleInternal symbol when a
                // re-declaration occurs. AngleInternal symbols will have their name intact. However,
                // the issue is that the current code put a lot of restrictions on AngleInternal
                // symbols. For examples:
                //  - CollectVariables.cpp will not consider AngleInternal as varying output variables.
                //  - SymbolTable.cpp will throw an exception if AngleInternal symbols are declared by
                //  users. In this case, it would be gl_ClipDistance. This is because
                //  TSymbolTable::declare() only accepts an UserDefined symbol.
                //  - And potentially many other places that have some assumptions that haven't been
                //  discovered yet.
                //
                // If re-declared gl_ClipDistance was to be an AngleInternal symbol, a special "if (name
                // == "gl_ClipDistance")" handling would have to be put into all the above mentioned
                // cases. TParseContext::declareVariable() function would also have to be modified in
                // order to assign AngleInternal symbol type to the re-declared gl_ClipDistance
                // variable.
                // Compare to only this place has to be handled if re-declared gl_ClipDistance is
                // treated as an UserDefined symbol.
                //
                // Also, gl_LastFragData should be added.
                //
                return name;
            }
            ImmutableStringBuilder prefixedName(kUnhashedNamePrefix.length() + name.length());
            prefixedName << kUnhashedNamePrefix << name;
            ImmutableString res = prefixedName;
            AddToNameMapIfNotMapped(name, res, nameMap);
            return res;
        }
    
        // Has a hash function
        ImmutableString hashedName = HashName(name, hashFunction);
        AddToNameMapIfNotMapped(name, hashedName, nameMap);
        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