ValidateMultiviewWebGL.cpp

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Author : Olli Etuaho
Date : 2017-07-05 14:50:54
Hash : cccf2b00
Message : Reorganize AST traversal utility code Define TIntermTraverser and TIntermLValueTrackingTraverser in a separate header file. hash() function is moved out from TIntermTraverser as it is not related to the core functionality of traversing and transforming ASTs. Also reorganize some traversers to follow common conventions: - Intermediate output is now in OutputTree.h/.cpp - Max tree depth check is now in IsASTDepthBelowLimit.h/.cpp BUG=angleproject:1490 TEST=angle_unittests Change-Id: Id4968aa9d4e24d0c5bac90dc147fc9f310de0184 Reviewed-on: https://chromium-review.googlesource.com/559531 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Corentin Wallez <cwallez@chromium.org> Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
src/compiler/translator/ValidateMultiviewWebGL.cpp
//
// Copyright (c) 2002-2016 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.
//
// ValidateMultiviewWebGL.cpp:
//   Validate the AST according to rules in the WEBGL_multiview extension spec. Only covers those
//   rules not already covered in ParseContext.
//

#include "compiler/translator/ValidateMultiviewWebGL.h"

#include <array>

#include "angle_gl.h"
#include "compiler/translator/Diagnostics.h"
#include "compiler/translator/FindSymbolNode.h"
#include "compiler/translator/IntermTraverse.h"
#include "compiler/translator/SymbolTable.h"

namespace sh
{

namespace
{

class ValidateMultiviewTraverser : public TIntermTraverser
{
  public:
    // Check for errors and write error messages to diagnostics. Returns true if there are no
    // errors.
    static bool validate(TIntermBlock *root,
                         GLenum shaderType,
                         const TSymbolTable &symbolTable,
                         int shaderVersion,
                         bool multiview2,
                         TDiagnostics *diagnostics);

    bool isValid() { return mValid; }

  protected:
    void visitSymbol(TIntermSymbol *node) override;
    bool visitBinary(Visit visit, TIntermBinary *node) override;
    bool visitUnary(Visit visit, TIntermUnary *node) override;
    bool visitIfElse(Visit visit, TIntermIfElse *node) override;
    bool visitAggregate(Visit visit, TIntermAggregate *node) override;

  private:
    ValidateMultiviewTraverser(GLenum shaderType,
                               const TSymbolTable &symbolTable,
                               int shaderVersion,
                               bool multiview2,
                               TDiagnostics *diagnostics);

    static bool IsGLPosition(TIntermNode *node);
    static bool IsGLViewIDOVR(TIntermNode *node);
    static bool IsSimpleAssignmentToGLPositionX(TIntermBinary *node);
    static bool IsSimpleAssignmentToGLPosition(TIntermBinary *node);

    void validateAndTraverseViewIDConditionalBlock(TIntermBlock *block, const char *token);

    bool mValid;
    bool mMultiview2;
    GLenum mShaderType;
    const TSymbolTable &mSymbolTable;
    const int mShaderVersion;

    bool mInsideViewIDConditional;  // Only set if mMultiview2 is false.
    bool mInsideRestrictedAssignment;
    bool mGLPositionAllowed;
    bool mViewIDOVRAllowed;

    TDiagnostics *mDiagnostics;
};

bool ValidateMultiviewTraverser::validate(TIntermBlock *root,
                                          GLenum shaderType,
                                          const TSymbolTable &symbolTable,
                                          int shaderVersion,
                                          bool multiview2,
                                          TDiagnostics *diagnostics)
{
    ValidateMultiviewTraverser validate(shaderType, symbolTable, shaderVersion, multiview2,
                                        diagnostics);
    ASSERT(root);
    root->traverse(&validate);
    return validate.isValid();
}

ValidateMultiviewTraverser::ValidateMultiviewTraverser(GLenum shaderType,
                                                       const TSymbolTable &symbolTable,
                                                       int shaderVersion,
                                                       bool multiview2,
                                                       TDiagnostics *diagnostics)
    : TIntermTraverser(true, true, true),
      mValid(true),
      mMultiview2(multiview2),
      mShaderType(shaderType),
      mSymbolTable(symbolTable),
      mShaderVersion(shaderVersion),
      mInsideViewIDConditional(false),
      mInsideRestrictedAssignment(false),
      mGLPositionAllowed(multiview2),
      mViewIDOVRAllowed(multiview2),
      mDiagnostics(diagnostics)
{
}

bool ValidateMultiviewTraverser::IsGLPosition(TIntermNode *node)
{
    TIntermSymbol *symbolNode = node->getAsSymbolNode();
    return (symbolNode && symbolNode->getName().getString() == "gl_Position");
}

bool ValidateMultiviewTraverser::IsGLViewIDOVR(TIntermNode *node)
{
    TIntermSymbol *symbolNode = node->getAsSymbolNode();
    return (symbolNode && symbolNode->getName().getString() == "gl_ViewID_OVR");
}

bool ValidateMultiviewTraverser::IsSimpleAssignmentToGLPositionX(TIntermBinary *node)
{
    if (node->getOp() == EOpAssign)
    {
        TIntermSwizzle *leftAsSwizzle = node->getLeft()->getAsSwizzleNode();
        if (leftAsSwizzle && IsGLPosition(leftAsSwizzle->getOperand()) &&
            leftAsSwizzle->offsetsMatch(0))
        {
            return true;
        }
        TIntermBinary *leftAsBinary = node->getLeft()->getAsBinaryNode();
        if (leftAsBinary && leftAsBinary->getOp() == EOpIndexDirect &&
            IsGLPosition(leftAsBinary->getLeft()) &&
            leftAsBinary->getRight()->getAsConstantUnion()->getIConst(0) == 0)
        {
            return true;
        }
    }
    return false;
}

bool ValidateMultiviewTraverser::IsSimpleAssignmentToGLPosition(TIntermBinary *node)
{
    if (node->getOp() == EOpAssign)
    {
        if (IsGLPosition(node->getLeft()))
        {
            return true;
        }
        TIntermSwizzle *leftAsSwizzle = node->getLeft()->getAsSwizzleNode();
        if (leftAsSwizzle && IsGLPosition(leftAsSwizzle->getOperand()))
        {
            return true;
        }
        TIntermBinary *leftAsBinary = node->getLeft()->getAsBinaryNode();
        if (leftAsBinary && leftAsBinary->getOp() == EOpIndexDirect &&
            IsGLPosition(leftAsBinary->getLeft()))
        {
            return true;
        }
    }
    return false;
}

void ValidateMultiviewTraverser::visitSymbol(TIntermSymbol *node)
{
    if (IsGLPosition(node) && !mGLPositionAllowed)
    {
        ASSERT(!mMultiview2);
        mDiagnostics->error(node->getLine(),
                            "Disallowed use of gl_Position when using OVR_multiview",
                            "gl_Position");
        mValid = false;
    }
    else if (IsGLViewIDOVR(node) && !mViewIDOVRAllowed)
    {
        ASSERT(!mMultiview2);
        mDiagnostics->error(node->getLine(),
                            "Disallowed use of gl_ViewID_OVR when using OVR_multiview",
                            "gl_ViewID_OVR");
        mValid = false;
    }
    else if (!mMultiview2 && mShaderType == GL_FRAGMENT_SHADER)
    {
        std::array<const char *, 3> disallowedFragmentShaderSymbols{
            {"gl_FragCoord", "gl_PointCoord", "gl_FrontFacing"}};
        for (auto disallowedSymbol : disallowedFragmentShaderSymbols)
        {
            if (node->getSymbol() == disallowedSymbol)
            {
                mDiagnostics->error(
                    node->getLine(),
                    "Disallowed use of a built-in variable when using OVR_multiview",
                    disallowedSymbol);
                mValid = false;
            }
        }
    }
}

bool ValidateMultiviewTraverser::visitBinary(Visit visit, TIntermBinary *node)
{
    if (!mMultiview2 && mShaderType == GL_VERTEX_SHADER)
    {
        if (visit == PreVisit)
        {
            ASSERT(!mInsideViewIDConditional || mInsideRestrictedAssignment);
            if (node->isAssignment())
            {
                if (mInsideRestrictedAssignment)
                {
                    mDiagnostics->error(node->getLine(),
                                        "Disallowed assignment inside assignment to gl_Position.x "
                                        "when using OVR_multiview",
                                        GetOperatorString(node->getOp()));
                    mValid = false;
                }
                else if (IsSimpleAssignmentToGLPositionX(node) &&
                         FindSymbolNode(node->getRight(), "gl_ViewID_OVR", EbtUInt))
                {
                    if (!getParentNode()->getAsBlock())
                    {
                        mDiagnostics->error(node->getLine(),
                                            "Disallowed use of assignment to gl_Position.x "
                                            "when using OVR_multiview",
                                            "=");
                        mValid = false;
                    }
                    mInsideRestrictedAssignment = true;
                    mViewIDOVRAllowed           = true;
                    node->getRight()->traverse(this);
                    mInsideRestrictedAssignment = false;
                    mViewIDOVRAllowed           = false;
                    return false;
                }
                else if (IsSimpleAssignmentToGLPosition(node))
                {
                    node->getRight()->traverse(this);
                    return false;
                }
            }
        }
    }
    return true;
}

bool ValidateMultiviewTraverser::visitUnary(Visit visit, TIntermUnary *node)
{
    if (visit == PreVisit && !mMultiview2 && mInsideRestrictedAssignment)
    {
        if (node->isAssignment())
        {
            mDiagnostics->error(node->getLine(),
                                "Disallowed unary operator inside assignment to gl_Position.x when "
                                "using OVR_multiview",
                                GetOperatorString(node->getOp()));
            mValid = false;
        }
    }
    return true;
}

void ValidateMultiviewTraverser::validateAndTraverseViewIDConditionalBlock(TIntermBlock *block,
                                                                           const char *token)
{
    if (block->getSequence()->size() > 1)
    {
        mDiagnostics->error(block->getLine(),
                            "Only one assignment to gl_Position allowed inside if block dependent "
                            "on gl_ViewID_OVR when using OVR_multiview",
                            token);
        mValid = false;
    }
    else if (block->getSequence()->size() == 1)
    {
        TIntermBinary *assignment = block->getSequence()->at(0)->getAsBinaryNode();
        if (assignment && IsSimpleAssignmentToGLPositionX(assignment))
        {
            mInsideRestrictedAssignment = true;
            assignment->getRight()->traverse(this);
            mInsideRestrictedAssignment = false;
        }
        else
        {
            mDiagnostics->error(block->getLine(),
                                "Only one assignment to gl_Position.x allowed inside if block "
                                "dependent on gl_ViewID_OVR when using OVR_multiview",
                                token);
            mValid = false;
        }
    }
}

bool ValidateMultiviewTraverser::visitIfElse(Visit visit, TIntermIfElse *node)
{
    if (!mMultiview2 && mShaderType == GL_VERTEX_SHADER)
    {
        ASSERT(visit == PreVisit);

        // Check if the if statement refers to gl_ViewID_OVR and if it does so correctly
        TIntermBinary *binaryCondition              = node->getCondition()->getAsBinaryNode();
        bool conditionIsAllowedComparisonWithViewID = false;
        if (binaryCondition && binaryCondition->getOp() == EOpEqual)
        {
            conditionIsAllowedComparisonWithViewID =
                IsGLViewIDOVR(binaryCondition->getLeft()) &&
                binaryCondition->getRight()->getAsConstantUnion() &&
                binaryCondition->getRight()->getQualifier() == EvqConst;
            if (!conditionIsAllowedComparisonWithViewID)
            {
                conditionIsAllowedComparisonWithViewID =
                    IsGLViewIDOVR(binaryCondition->getRight()) &&
                    binaryCondition->getLeft()->getAsConstantUnion() &&
                    binaryCondition->getLeft()->getQualifier() == EvqConst;
            }
        }
        if (conditionIsAllowedComparisonWithViewID)
        {
            mInsideViewIDConditional = true;
            if (node->getTrueBlock())
            {
                validateAndTraverseViewIDConditionalBlock(node->getTrueBlock(), "if");
            }
            else
            {
                mDiagnostics->error(node->getLine(), "Expected assignment to gl_Position.x", "if");
            }
            if (node->getFalseBlock())
            {
                validateAndTraverseViewIDConditionalBlock(node->getFalseBlock(), "else");
            }
            mInsideViewIDConditional = false;
        }
        else
        {
            node->getCondition()->traverse(this);
            if (node->getTrueBlock())
            {
                node->getTrueBlock()->traverse(this);
            }
            if (node->getFalseBlock())
            {
                node->getFalseBlock()->traverse(this);
            }
        }
        return false;
    }
    return true;
}

bool ValidateMultiviewTraverser::visitAggregate(Visit visit, TIntermAggregate *node)
{
    if (visit == PreVisit && !mMultiview2 && mInsideRestrictedAssignment)
    {
        // Check if the node is an user-defined function call or if an l-value is required, or if
        // there are possible visible side effects, such as image writes.
        if (node->getOp() == EOpCallFunctionInAST)
        {
            mDiagnostics->error(node->getLine(),
                                "Disallowed user defined function call inside assignment to "
                                "gl_Position.x when using OVR_multiview",
                                GetOperatorString(node->getOp()));
            mValid = false;
        }
        else if (node->getOp() == EOpCallBuiltInFunction &&
                 node->getFunctionSymbolInfo()->getName() == "imageStore")
        {
            // TODO(oetuaho@nvidia.com): Record which built-in functions have side effects in
            // the symbol info instead.
            mDiagnostics->error(node->getLine(),
                                "Disallowed function call with side effects inside assignment "
                                "to gl_Position.x when using OVR_multiview",
                                GetOperatorString(node->getOp()));
            mValid = false;
        }
        else if (!node->isConstructor())
        {
            TFunction *builtInFunc = static_cast<TFunction *>(
                mSymbolTable.findBuiltIn(node->getSymbolTableMangledName(), mShaderVersion));
            for (size_t paramIndex = 0u; paramIndex < builtInFunc->getParamCount(); ++paramIndex)
            {
                TQualifier qualifier = builtInFunc->getParam(paramIndex).type->getQualifier();
                if (qualifier == EvqOut || qualifier == EvqInOut)
                {
                    mDiagnostics->error(node->getLine(),
                                        "Disallowed use of a function with an out parameter inside "
                                        "assignment to gl_Position.x when using OVR_multiview",
                                        GetOperatorString(node->getOp()));
                    mValid = false;
                }
            }
        }
    }
    return true;
}

}  // anonymous namespace

bool ValidateMultiviewWebGL(TIntermBlock *root,
                            GLenum shaderType,
                            const TSymbolTable &symbolTable,
                            int shaderVersion,
                            bool multiview2,
                            TDiagnostics *diagnostics)
{
    if (shaderType == GL_VERTEX_SHADER && !FindSymbolNode(root, "gl_ViewID_OVR", EbtUInt))
    {
        return true;
    }
    return ValidateMultiviewTraverser::validate(root, shaderType, symbolTable, shaderVersion,
                                                multiview2, diagnostics);
}

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

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