InitializeVariables.cpp

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Author : Stuart Morgan
Date : 2019-08-14 12:25:12
Hash : 9d737966
Message : Standardize copyright notices to project style For all "ANGLE Project" copyrights, standardize to the format specified by the style guide. Changes: - "Copyright (c)" and "Copyright(c)" changed to just "Copyright". - Removed the second half of date ranges ("Y1Y1-Y2Y2"->"Y1Y1"). - Fixed a small number of files that had no copyright date using the initial commit year from the version control history. - Fixed one instance of copyright being "The ANGLE Project" rather than "The ANGLE Project Authors" These changes are applied both to the copyright of source file, and where applicable to copyright statements that are generated by templates. BUG=angleproject:3811 Change-Id: I973dd65e4ef9deeba232d5be74c768256a0eb2e5 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1754397 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org>
src/compiler/translator/tree_ops/InitializeVariables.cpp
//
// 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.
//

#include "compiler/translator/tree_ops/InitializeVariables.h"

#include "angle_gl.h"
#include "common/debug.h"
#include "compiler/translator/StaticType.h"
#include "compiler/translator/SymbolTable.h"
#include "compiler/translator/tree_util/FindMain.h"
#include "compiler/translator/tree_util/IntermNode_util.h"
#include "compiler/translator/tree_util/IntermTraverse.h"
#include "compiler/translator/util.h"

namespace sh
{

namespace
{

void AddArrayZeroInitSequence(const TIntermTyped *initializedNode,
                              bool canUseLoopsToInitialize,
                              bool highPrecisionSupported,
                              TIntermSequence *initSequenceOut,
                              TSymbolTable *symbolTable);

void AddStructZeroInitSequence(const TIntermTyped *initializedNode,
                               bool canUseLoopsToInitialize,
                               bool highPrecisionSupported,
                               TIntermSequence *initSequenceOut,
                               TSymbolTable *symbolTable);

TIntermBinary *CreateZeroInitAssignment(const TIntermTyped *initializedNode)
{
    TIntermTyped *zero = CreateZeroNode(initializedNode->getType());
    return new TIntermBinary(EOpAssign, initializedNode->deepCopy(), zero);
}

void AddZeroInitSequence(const TIntermTyped *initializedNode,
                         bool canUseLoopsToInitialize,
                         bool highPrecisionSupported,
                         TIntermSequence *initSequenceOut,
                         TSymbolTable *symbolTable)
{
    if (initializedNode->isArray())
    {
        AddArrayZeroInitSequence(initializedNode, canUseLoopsToInitialize, highPrecisionSupported,
                                 initSequenceOut, symbolTable);
    }
    else if (initializedNode->getType().isStructureContainingArrays() ||
             initializedNode->getType().isNamelessStruct())
    {
        AddStructZeroInitSequence(initializedNode, canUseLoopsToInitialize, highPrecisionSupported,
                                  initSequenceOut, symbolTable);
    }
    else
    {
        initSequenceOut->push_back(CreateZeroInitAssignment(initializedNode));
    }
}

void AddStructZeroInitSequence(const TIntermTyped *initializedNode,
                               bool canUseLoopsToInitialize,
                               bool highPrecisionSupported,
                               TIntermSequence *initSequenceOut,
                               TSymbolTable *symbolTable)
{
    ASSERT(initializedNode->getBasicType() == EbtStruct);
    const TStructure *structType = initializedNode->getType().getStruct();
    for (int i = 0; i < static_cast<int>(structType->fields().size()); ++i)
    {
        TIntermBinary *element = new TIntermBinary(EOpIndexDirectStruct,
                                                   initializedNode->deepCopy(), CreateIndexNode(i));
        // Structs can't be defined inside structs, so the type of a struct field can't be a
        // nameless struct.
        ASSERT(!element->getType().isNamelessStruct());
        AddZeroInitSequence(element, canUseLoopsToInitialize, highPrecisionSupported,
                            initSequenceOut, symbolTable);
    }
}

void AddArrayZeroInitStatementList(const TIntermTyped *initializedNode,
                                   bool canUseLoopsToInitialize,
                                   bool highPrecisionSupported,
                                   TIntermSequence *initSequenceOut,
                                   TSymbolTable *symbolTable)
{
    for (unsigned int i = 0; i < initializedNode->getOutermostArraySize(); ++i)
    {
        TIntermBinary *element =
            new TIntermBinary(EOpIndexDirect, initializedNode->deepCopy(), CreateIndexNode(i));
        AddZeroInitSequence(element, canUseLoopsToInitialize, highPrecisionSupported,
                            initSequenceOut, symbolTable);
    }
}

void AddArrayZeroInitForLoop(const TIntermTyped *initializedNode,
                             bool highPrecisionSupported,
                             TIntermSequence *initSequenceOut,
                             TSymbolTable *symbolTable)
{
    ASSERT(initializedNode->isArray());
    const TType *mediumpIndexType = StaticType::Get<EbtInt, EbpMedium, EvqTemporary, 1, 1>();
    const TType *highpIndexType   = StaticType::Get<EbtInt, EbpHigh, EvqTemporary, 1, 1>();
    TVariable *indexVariable =
        CreateTempVariable(symbolTable, highPrecisionSupported ? highpIndexType : mediumpIndexType);

    TIntermSymbol *indexSymbolNode = CreateTempSymbolNode(indexVariable);
    TIntermDeclaration *indexInit =
        CreateTempInitDeclarationNode(indexVariable, CreateZeroNode(indexVariable->getType()));
    TIntermConstantUnion *arraySizeNode = CreateIndexNode(initializedNode->getOutermostArraySize());
    TIntermBinary *indexSmallerThanSize =
        new TIntermBinary(EOpLessThan, indexSymbolNode->deepCopy(), arraySizeNode);
    TIntermUnary *indexIncrement =
        new TIntermUnary(EOpPreIncrement, indexSymbolNode->deepCopy(), nullptr);

    TIntermBlock *forLoopBody       = new TIntermBlock();
    TIntermSequence *forLoopBodySeq = forLoopBody->getSequence();

    TIntermBinary *element = new TIntermBinary(EOpIndexIndirect, initializedNode->deepCopy(),
                                               indexSymbolNode->deepCopy());
    AddZeroInitSequence(element, true, highPrecisionSupported, forLoopBodySeq, symbolTable);

    TIntermLoop *forLoop =
        new TIntermLoop(ELoopFor, indexInit, indexSmallerThanSize, indexIncrement, forLoopBody);
    initSequenceOut->push_back(forLoop);
}

void AddArrayZeroInitSequence(const TIntermTyped *initializedNode,
                              bool canUseLoopsToInitialize,
                              bool highPrecisionSupported,
                              TIntermSequence *initSequenceOut,
                              TSymbolTable *symbolTable)
{
    // The array elements are assigned one by one to keep the AST compatible with ESSL 1.00 which
    // doesn't have array assignment. We'll do this either with a for loop or just a list of
    // statements assigning to each array index. Note that it is important to have the array init in
    // the right order to workaround http://crbug.com/709317
    bool isSmallArray = initializedNode->getOutermostArraySize() <= 1u ||
                        (initializedNode->getBasicType() != EbtStruct &&
                         !initializedNode->getType().isArrayOfArrays() &&
                         initializedNode->getOutermostArraySize() <= 3u);
    if (initializedNode->getQualifier() == EvqFragData ||
        initializedNode->getQualifier() == EvqFragmentOut || isSmallArray ||
        !canUseLoopsToInitialize)
    {
        // Fragment outputs should not be indexed by non-constant indices.
        // Also it doesn't make sense to use loops to initialize very small arrays.
        AddArrayZeroInitStatementList(initializedNode, canUseLoopsToInitialize,
                                      highPrecisionSupported, initSequenceOut, symbolTable);
    }
    else
    {
        AddArrayZeroInitForLoop(initializedNode, highPrecisionSupported, initSequenceOut,
                                symbolTable);
    }
}

void InsertInitCode(TIntermSequence *mainBody,
                    const InitVariableList &variables,
                    TSymbolTable *symbolTable,
                    int shaderVersion,
                    const TExtensionBehavior &extensionBehavior,
                    bool canUseLoopsToInitialize,
                    bool highPrecisionSupported)
{
    for (const auto &var : variables)
    {
        // Note that tempVariableName will reference a short-lived char array here - that's fine
        // since we're only using it to find symbols.
        ImmutableString tempVariableName(var.name.c_str(), var.name.length());

        TIntermTyped *initializedSymbol = nullptr;
        if (var.isBuiltIn())
        {
            initializedSymbol =
                ReferenceBuiltInVariable(tempVariableName, *symbolTable, shaderVersion);
            if (initializedSymbol->getQualifier() == EvqFragData &&
                !IsExtensionEnabled(extensionBehavior, TExtension::EXT_draw_buffers))
            {
                // If GL_EXT_draw_buffers is disabled, only the 0th index of gl_FragData can be
                // written to.
                // TODO(oetuaho): This is a bit hacky and would be better to remove, if we came up
                // with a good way to do it. Right now "gl_FragData" in symbol table is initialized
                // to have the array size of MaxDrawBuffers, and the initialization happens before
                // the shader sets the extensions it is using.
                initializedSymbol =
                    new TIntermBinary(EOpIndexDirect, initializedSymbol, CreateIndexNode(0));
            }
        }
        else
        {
            initializedSymbol = ReferenceGlobalVariable(tempVariableName, *symbolTable);
        }
        ASSERT(initializedSymbol != nullptr);

        TIntermSequence *initCode = CreateInitCode(initializedSymbol, canUseLoopsToInitialize,
                                                   highPrecisionSupported, symbolTable);
        mainBody->insert(mainBody->begin(), initCode->begin(), initCode->end());
    }
}

class InitializeLocalsTraverser : public TIntermTraverser
{
  public:
    InitializeLocalsTraverser(int shaderVersion,
                              TSymbolTable *symbolTable,
                              bool canUseLoopsToInitialize,
                              bool highPrecisionSupported)
        : TIntermTraverser(true, false, false, symbolTable),
          mShaderVersion(shaderVersion),
          mCanUseLoopsToInitialize(canUseLoopsToInitialize),
          mHighPrecisionSupported(highPrecisionSupported)
    {}

  protected:
    bool visitDeclaration(Visit visit, TIntermDeclaration *node) override
    {
        for (TIntermNode *declarator : *node->getSequence())
        {
            if (!mInGlobalScope && !declarator->getAsBinaryNode())
            {
                TIntermSymbol *symbol = declarator->getAsSymbolNode();
                ASSERT(symbol);
                if (symbol->variable().symbolType() == SymbolType::Empty)
                {
                    continue;
                }

                // Arrays may need to be initialized one element at a time, since ESSL 1.00 does not
                // support array constructors or assigning arrays.
                bool arrayConstructorUnavailable =
                    (symbol->isArray() || symbol->getType().isStructureContainingArrays()) &&
                    mShaderVersion == 100;
                // Nameless struct constructors can't be referred to, so they also need to be
                // initialized one element at a time.
                // TODO(oetuaho): Check if it makes sense to initialize using a loop, even if we
                // could use an initializer. It could at least reduce code size for very large
                // arrays, but could hurt runtime performance.
                if (arrayConstructorUnavailable || symbol->getType().isNamelessStruct())
                {
                    // SimplifyLoopConditions should have been run so the parent node of this node
                    // should not be a loop.
                    ASSERT(getParentNode()->getAsLoopNode() == nullptr);
                    // SeparateDeclarations should have already been run, so we don't need to worry
                    // about further declarators in this declaration depending on the effects of
                    // this declarator.
                    ASSERT(node->getSequence()->size() == 1);
                    insertStatementsInParentBlock(
                        TIntermSequence(), *CreateInitCode(symbol, mCanUseLoopsToInitialize,
                                                           mHighPrecisionSupported, mSymbolTable));
                }
                else
                {
                    TIntermBinary *init =
                        new TIntermBinary(EOpInitialize, symbol, CreateZeroNode(symbol->getType()));
                    queueReplacementWithParent(node, symbol, init, OriginalNode::BECOMES_CHILD);
                }
            }
        }
        return false;
    }

  private:
    int mShaderVersion;
    bool mCanUseLoopsToInitialize;
    bool mHighPrecisionSupported;
};

}  // namespace

TIntermSequence *CreateInitCode(const TIntermTyped *initializedSymbol,
                                bool canUseLoopsToInitialize,
                                bool highPrecisionSupported,
                                TSymbolTable *symbolTable)
{
    TIntermSequence *initCode = new TIntermSequence();
    AddZeroInitSequence(initializedSymbol, canUseLoopsToInitialize, highPrecisionSupported,
                        initCode, symbolTable);
    return initCode;
}

void InitializeUninitializedLocals(TIntermBlock *root,
                                   int shaderVersion,
                                   bool canUseLoopsToInitialize,
                                   bool highPrecisionSupported,
                                   TSymbolTable *symbolTable)
{
    InitializeLocalsTraverser traverser(shaderVersion, symbolTable, canUseLoopsToInitialize,
                                        highPrecisionSupported);
    root->traverse(&traverser);
    traverser.updateTree();
}

void InitializeVariables(TIntermBlock *root,
                         const InitVariableList &vars,
                         TSymbolTable *symbolTable,
                         int shaderVersion,
                         const TExtensionBehavior &extensionBehavior,
                         bool canUseLoopsToInitialize,
                         bool highPrecisionSupported)
{
    TIntermBlock *body = FindMainBody(root);
    InsertInitCode(body->getSequence(), vars, symbolTable, shaderVersion, extensionBehavior,
                   canUseLoopsToInitialize, highPrecisionSupported);
}

}  // namespace sh
kc3-lang/angle/src/compiler/translator/tree_ops/InitializeVariables.cpp

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kc3-lang/angle /src/compiler/translator/tree_ops/InitializeVariables.cpp
