RewriteTexelFetchOffset.cpp

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Author : Shahbaz Youssefi
Date : 2019-08-19 16:32:13
Hash : 472c74c6
Message : Translator: Allow tree validation in children of TCompiler This is to be able to perform validation inside TranslatorVulkan, even if it's through ASSERTs. Additionally, every transformation is changed such that they do their validation themselves. TIntermTraverser::updateTree() performs the validation, which indirectly validates many of three tree transformations. Some of the more ancient transformations that don't use this function directly call TCompiler::validateAST. Bug: angleproject:2733 Change-Id: Ie4af029d34e053c5ad1dc8c2c2568eecd625d344 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1761149 Reviewed-by: Geoff Lang <geofflang@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>

src/compiler/translator/tree_ops/RewriteTexelFetchOffset.cpp

//
// Copyright 2016 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.
//
// Implementation of texelFetchOffset translation issue workaround.
// See header for more info.

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

#include "common/angleutils.h"
#include "compiler/translator/SymbolTable.h"
#include "compiler/translator/tree_util/IntermNode_util.h"
#include "compiler/translator/tree_util/IntermTraverse.h"

namespace sh
{

namespace
{

class Traverser : public TIntermTraverser
{
  public:
    ANGLE_NO_DISCARD static bool Apply(TCompiler *compiler,
                                       TIntermNode *root,
                                       const TSymbolTable &symbolTable,
                                       int shaderVersion);

  private:
    Traverser(const TSymbolTable &symbolTable, int shaderVersion);
    bool visitAggregate(Visit visit, TIntermAggregate *node) override;
    void nextIteration();

    const TSymbolTable *symbolTable;
    const int shaderVersion;
    bool mFound = false;
};

Traverser::Traverser(const TSymbolTable &symbolTable, int shaderVersion)
    : TIntermTraverser(true, false, false), symbolTable(&symbolTable), shaderVersion(shaderVersion)
{}

// static
bool Traverser::Apply(TCompiler *compiler,
                      TIntermNode *root,
                      const TSymbolTable &symbolTable,
                      int shaderVersion)
{
    Traverser traverser(symbolTable, shaderVersion);
    do
    {
        traverser.nextIteration();
        root->traverse(&traverser);
        if (traverser.mFound)
        {
            if (!traverser.updateTree(compiler, root))
            {
                return false;
            }
        }
    } while (traverser.mFound);

    return true;
}

void Traverser::nextIteration()
{
    mFound = false;
}

bool Traverser::visitAggregate(Visit visit, TIntermAggregate *node)
{
    if (mFound)
    {
        return false;
    }

    // Decide if the node represents the call of texelFetchOffset.
    if (node->getOp() != EOpCallBuiltInFunction)
    {
        return true;
    }

    ASSERT(node->getFunction()->symbolType() == SymbolType::BuiltIn);
    if (node->getFunction()->name() != "texelFetchOffset")
    {
        return true;
    }

    // Potential problem case detected, apply workaround.
    const TIntermSequence *sequence = node->getSequence();
    ASSERT(sequence->size() == 4u);

    // Decide if the sampler is a 2DArray sampler. In that case position is ivec3 and offset is
    // ivec2.
    bool is2DArray = sequence->at(1)->getAsTyped()->getNominalSize() == 3 &&
                     sequence->at(3)->getAsTyped()->getNominalSize() == 2;

    // Create new node that represents the call of function texelFetch.
    // Its argument list will be: texelFetch(sampler, Position+offset, lod).

    TIntermSequence *texelFetchArguments = new TIntermSequence();

    // sampler
    texelFetchArguments->push_back(sequence->at(0));

    // Position
    TIntermTyped *texCoordNode = sequence->at(1)->getAsTyped();
    ASSERT(texCoordNode);

    // offset
    TIntermTyped *offsetNode = nullptr;
    ASSERT(sequence->at(3)->getAsTyped());
    if (is2DArray)
    {
        // For 2DArray samplers, Position is ivec3 and offset is ivec2;
        // So offset must be converted into an ivec3 before being added to Position.
        TIntermSequence *constructOffsetIvecArguments = new TIntermSequence();
        constructOffsetIvecArguments->push_back(sequence->at(3)->getAsTyped());

        TIntermTyped *zeroNode = CreateZeroNode(TType(EbtInt));
        constructOffsetIvecArguments->push_back(zeroNode);

        offsetNode = TIntermAggregate::CreateConstructor(texCoordNode->getType(),
                                                         constructOffsetIvecArguments);
        offsetNode->setLine(texCoordNode->getLine());
    }
    else
    {
        offsetNode = sequence->at(3)->getAsTyped();
    }

    // Position+offset
    TIntermBinary *add = new TIntermBinary(EOpAdd, texCoordNode, offsetNode);
    add->setLine(texCoordNode->getLine());
    texelFetchArguments->push_back(add);

    // lod
    texelFetchArguments->push_back(sequence->at(2));

    ASSERT(texelFetchArguments->size() == 3u);

    TIntermTyped *texelFetchNode = CreateBuiltInFunctionCallNode("texelFetch", texelFetchArguments,
                                                                 *symbolTable, shaderVersion);
    texelFetchNode->setLine(node->getLine());

    // Replace the old node by this new node.
    queueReplacement(texelFetchNode, OriginalNode::IS_DROPPED);
    mFound = true;
    return false;
}

}  // anonymous namespace

bool RewriteTexelFetchOffset(TCompiler *compiler,
                             TIntermNode *root,
                             const TSymbolTable &symbolTable,
                             int shaderVersion)
{
    // texelFetchOffset is only valid in GLSL 3.0 and later.
    if (shaderVersion < 300)
        return true;

    return Traverser::Apply(compiler, root, symbolTable, shaderVersion);
}

}  // namespace sh

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

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