1 files changed, 368 insertions, 0 deletions
diff --git a/gfx/angle/checkout/src/compiler/translator/ValidateVaryingLocations.cpp b/gfx/angle/checkout/src/compiler/translator/ValidateVaryingLocations.cpp
new file mode 100644
index 0000000000..3c2eeeb5bc
--- /dev/null
+++ b/gfx/angle/checkout/src/compiler/translator/ValidateVaryingLocations.cpp
@@ -0,0 +1,368 @@
+//
+// 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.
+//
+// The ValidateVaryingLocations function checks if there exists location conflicts on shader
+// varyings.
+//
+
+#include "ValidateVaryingLocations.h"
+
+#include "compiler/translator/Diagnostics.h"
+#include "compiler/translator/SymbolTable.h"
+#include "compiler/translator/tree_util/IntermTraverse.h"
+#include "compiler/translator/util.h"
+
+namespace sh
+{
+
+namespace
+{
+
+void error(const TIntermSymbol &symbol, const char *reason, TDiagnostics *diagnostics)
+{
+    diagnostics->error(symbol.getLine(), reason, symbol.getName().data());
+}
+
+int GetStructLocationCount(const TStructure *structure);
+
+int GetFieldLocationCount(const TField *field)
+{
+    int field_size         = 0;
+    const TType *fieldType = field->type();
+
+    if (fieldType->getStruct() != nullptr)
+    {
+        field_size = GetStructLocationCount(fieldType->getStruct());
+    }
+    else if (fieldType->isMatrix())
+    {
+        field_size = fieldType->getNominalSize();
+    }
+    else
+    {
+        ASSERT(fieldType->getSecondarySize() == 1);
+        field_size = 1;
+    }
+
+    if (fieldType->isArray())
+    {
+        field_size *= fieldType->getArraySizeProduct();
+    }
+
+    return field_size;
+}
+
+int GetStructLocationCount(const TStructure *structure)
+{
+    int totalLocation = 0;
+    for (const TField *field : structure->fields())
+    {
+        totalLocation += GetFieldLocationCount(field);
+    }
+    return totalLocation;
+}
+
+int GetInterfaceBlockLocationCount(const TType &varyingType, bool ignoreVaryingArraySize)
+{
+    int totalLocation = 0;
+    for (const TField *field : varyingType.getInterfaceBlock()->fields())
+    {
+        totalLocation += GetFieldLocationCount(field);
+    }
+
+    if (!ignoreVaryingArraySize && varyingType.isArray())
+    {
+        totalLocation *= varyingType.getArraySizeProduct();
+    }
+    return totalLocation;
+}
+
+int GetLocationCount(const TType &varyingType, bool ignoreVaryingArraySize)
+{
+    ASSERT(!varyingType.isInterfaceBlock());
+
+    if (varyingType.getStruct() != nullptr)
+    {
+        int totalLocation = 0;
+        for (const TField *field : varyingType.getStruct()->fields())
+        {
+            const TType *fieldType = field->type();
+            ASSERT(fieldType->getStruct() == nullptr && !fieldType->isArray());
+
+            totalLocation += GetFieldLocationCount(field);
+        }
+        return totalLocation;
+    }
+
+    ASSERT(varyingType.isMatrix() || varyingType.getSecondarySize() == 1);
+    int elementLocationCount = varyingType.isMatrix() ? varyingType.getNominalSize() : 1;
+
+    // [GL_EXT_shader_io_blocks SPEC Chapter 4.4.1]
+    // Geometry shader inputs, tessellation control shader inputs and outputs, and tessellation
+    // evaluation inputs all have an additional level of arrayness relative to other shader inputs
+    // and outputs. This outer array level is removed from the type before considering how many
+    // locations the type consumes.
+    if (ignoreVaryingArraySize)
+    {
+        // Array-of-arrays cannot be inputs or outputs of a geometry shader.
+        // (GL_EXT_geometry_shader SPEC issues(5))
+        ASSERT(!varyingType.isArrayOfArrays());
+        return elementLocationCount;
+    }
+
+    return elementLocationCount * varyingType.getArraySizeProduct();
+}
+
+bool ShouldIgnoreVaryingArraySize(TQualifier qualifier, GLenum shaderType)
+{
+    bool isVaryingIn = IsShaderIn(qualifier) && qualifier != EvqPatchIn;
+
+    switch (shaderType)
+    {
+        case GL_GEOMETRY_SHADER:
+        case GL_TESS_EVALUATION_SHADER:
+            return isVaryingIn;
+        case GL_TESS_CONTROL_SHADER:
+            return (IsShaderOut(qualifier) && qualifier != EvqPatchOut) || isVaryingIn;
+        default:
+            return false;
+    }
+}
+
+struct SymbolAndField
+{
+    const TIntermSymbol *symbol;
+    const TField *field;
+};
+using LocationMap = std::map<int, SymbolAndField>;
+
+void MarkVaryingLocations(TDiagnostics *diagnostics,
+                          const TIntermSymbol *varying,
+                          const TField *field,
+                          int location,
+                          int elementCount,
+                          LocationMap *locationMap)
+{
+    for (int elementIndex = 0; elementIndex < elementCount; ++elementIndex)
+    {
+        const int offsetLocation = location + elementIndex;
+        auto conflict            = locationMap->find(offsetLocation);
+        if (conflict != locationMap->end())
+        {
+            std::stringstream strstr = sh::InitializeStream<std::stringstream>();
+            strstr << "'" << varying->getName();
+            if (field)
+            {
+                strstr << "." << field->name();
+            }
+            strstr << "' conflicting location with '" << conflict->second.symbol->getName();
+            if (conflict->second.field)
+            {
+                strstr << "." << conflict->second.field->name();
+            }
+            strstr << "'";
+            error(*varying, strstr.str().c_str(), diagnostics);
+        }
+        else
+        {
+            (*locationMap)[offsetLocation] = {varying, field};
+        }
+    }
+}
+
+using VaryingVector = std::vector<const TIntermSymbol *>;
+
+void ValidateShaderInterfaceAndAssignLocations(TDiagnostics *diagnostics,
+                                               const VaryingVector &varyingVector,
+                                               GLenum shaderType)
+{
+    // Location conflicts can only happen when there are two or more varyings in varyingVector.
+    if (varyingVector.size() <= 1)
+    {
+        return;
+    }
+
+    LocationMap locationMap;
+    for (const TIntermSymbol *varying : varyingVector)
+    {
+        const TType &varyingType = varying->getType();
+        const int location       = varyingType.getLayoutQualifier().location;
+        ASSERT(location >= 0);
+
+        bool ignoreVaryingArraySize =
+            ShouldIgnoreVaryingArraySize(varying->getQualifier(), shaderType);
+
+        // A varying is either:
+        //
+        // - A vector or matrix, which can take a number of contiguous locations
+        // - A struct, which also takes a number of contiguous locations
+        // - An interface block.
+        //
+        // Interface blocks can assign arbitrary locations to their fields, for example:
+        //
+        //     layout(location = 4) in block {
+        //         vec4 a;                         // gets location 4
+        //         vec4 b;                         // gets location 5
+        //         layout(location = 7) vec4 c;    // gets location 7
+        //         vec4 d;                         // gets location 8
+        //         layout (location = 1) vec4 e;   // gets location 1
+        //         vec4 f;                         // gets location 2
+        //     };
+        //
+        // The following code therefore takes two paths.  For non-interface-block types, the number
+        // of locations for the varying is calculated (elementCount), and all locations in
+        // [location, location + elementCount) are marked as occupied.
+        //
+        // For interface blocks, a similar algorithm is implemented except each field is
+        // individually marked with the location either advancing automatically or taking its value
+        // from the field's layout qualifier.
+
+        if (varyingType.isInterfaceBlock())
+        {
+            int currentLocation       = location;
+            bool anyFieldWithLocation = false;
+
+            for (const TField *field : varyingType.getInterfaceBlock()->fields())
+            {
+                const int fieldLocation = field->type()->getLayoutQualifier().location;
+                if (fieldLocation >= 0)
+                {
+                    currentLocation      = fieldLocation;
+                    anyFieldWithLocation = true;
+                }
+
+                const int fieldLocationCount = GetFieldLocationCount(field);
+                MarkVaryingLocations(diagnostics, varying, field, currentLocation,
+                                     fieldLocationCount, &locationMap);
+
+                currentLocation += fieldLocationCount;
+            }
+
+            // Array interface blocks can't have location qualifiers on fields.
+            ASSERT(ignoreVaryingArraySize || !anyFieldWithLocation || !varyingType.isArray());
+
+            if (!ignoreVaryingArraySize && varyingType.isArray())
+            {
+                // This is only reached if the varying is an array of interface blocks, with only a
+                // layout qualifier on the block itself, for example:
+                //
+                //     layout(location = 4) in block {
+                //         vec4 a;
+                //         vec4 b;
+                //         vec4 c;
+                //         vec4 d;
+                //     } instance[N];
+                //
+                // The locations for instance[0] are already marked by the above code, so we need to
+                // further mark locations occupied by instances [1, N).  |currentLocation| is
+                // already just past the end of instance[0], which is the beginning of instance[1].
+                //
+                int remainingLocations = currentLocation * (varyingType.getArraySizeProduct() - 1);
+                MarkVaryingLocations(diagnostics, varying, nullptr, currentLocation,
+                                     remainingLocations, &locationMap);
+            }
+        }
+        else
+        {
+            const int elementCount = GetLocationCount(varying->getType(), ignoreVaryingArraySize);
+            MarkVaryingLocations(diagnostics, varying, nullptr, location, elementCount,
+                                 &locationMap);
+        }
+    }
+}
+
+class ValidateVaryingLocationsTraverser : public TIntermTraverser
+{
+  public:
+    ValidateVaryingLocationsTraverser(GLenum shaderType);
+    void validate(TDiagnostics *diagnostics);
+
+  private:
+    bool visitDeclaration(Visit visit, TIntermDeclaration *node) override;
+    bool visitFunctionDefinition(Visit visit, TIntermFunctionDefinition *node) override;
+
+    VaryingVector mInputVaryingsWithLocation;
+    VaryingVector mOutputVaryingsWithLocation;
+    GLenum mShaderType;
+};
+
+ValidateVaryingLocationsTraverser::ValidateVaryingLocationsTraverser(GLenum shaderType)
+    : TIntermTraverser(true, false, false), mShaderType(shaderType)
+{}
+
+bool ValidateVaryingLocationsTraverser::visitDeclaration(Visit visit, TIntermDeclaration *node)
+{
+    const TIntermSequence &sequence = *(node->getSequence());
+    ASSERT(!sequence.empty());
+
+    const TIntermSymbol *symbol = sequence.front()->getAsSymbolNode();
+    if (symbol == nullptr)
+    {
+        return false;
+    }
+
+    if (symbol->variable().symbolType() == SymbolType::Empty)
+    {
+        return false;
+    }
+
+    // Collect varyings that have explicit 'location' qualifiers.
+    const TQualifier qualifier = symbol->getQualifier();
+    if (symbol->getType().getLayoutQualifier().location != -1)
+    {
+        if (IsVaryingIn(qualifier))
+        {
+            mInputVaryingsWithLocation.push_back(symbol);
+        }
+        else if (IsVaryingOut(qualifier))
+        {
+            mOutputVaryingsWithLocation.push_back(symbol);
+        }
+    }
+
+    return false;
+}
+
+bool ValidateVaryingLocationsTraverser::visitFunctionDefinition(Visit visit,
+                                                                TIntermFunctionDefinition *node)
+{
+    // We stop traversing function definitions because varyings cannot be defined in a function.
+    return false;
+}
+
+void ValidateVaryingLocationsTraverser::validate(TDiagnostics *diagnostics)
+{
+    ASSERT(diagnostics);
+
+    ValidateShaderInterfaceAndAssignLocations(diagnostics, mInputVaryingsWithLocation, mShaderType);
+    ValidateShaderInterfaceAndAssignLocations(diagnostics, mOutputVaryingsWithLocation,
+                                              mShaderType);
+}
+
+}  // anonymous namespace
+
+unsigned int CalculateVaryingLocationCount(const TType &varyingType, GLenum shaderType)
+{
+    const TQualifier qualifier        = varyingType.getQualifier();
+    const bool ignoreVaryingArraySize = ShouldIgnoreVaryingArraySize(qualifier, shaderType);
+
+    if (varyingType.isInterfaceBlock())
+    {
+        return GetInterfaceBlockLocationCount(varyingType, ignoreVaryingArraySize);
+    }
+
+    return GetLocationCount(varyingType, ignoreVaryingArraySize);
+}
+
+bool ValidateVaryingLocations(TIntermBlock *root, TDiagnostics *diagnostics, GLenum shaderType)
+{
+    ValidateVaryingLocationsTraverser varyingValidator(shaderType);
+    root->traverse(&varyingValidator);
+    int numErrorsBefore = diagnostics->numErrors();
+    varyingValidator.validate(diagnostics);
+    return (diagnostics->numErrors() == numErrorsBefore);
+}
+
+}  // namespace sh