1 files changed, 109 insertions, 0 deletions
diff --git a/gfx/angle/checkout/src/compiler/translator/BuiltinsWorkaroundGLSL.cpp b/gfx/angle/checkout/src/compiler/translator/BuiltinsWorkaroundGLSL.cpp
new file mode 100644
index 0000000000..6409f85c3c
--- /dev/null
+++ b/gfx/angle/checkout/src/compiler/translator/BuiltinsWorkaroundGLSL.cpp
@@ -0,0 +1,109 @@
+//
+// Copyright 2019 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/BuiltinsWorkaroundGLSL.h"
+
+#include "angle_gl.h"
+#include "compiler/translator/Symbol.h"
+#include "compiler/translator/SymbolTable.h"
+#include "compiler/translator/tree_util/BuiltIn.h"
+
+namespace sh
+{
+
+namespace
+{
+constexpr const ImmutableString kGlInstanceIDString("gl_InstanceID");
+constexpr const ImmutableString kGlVertexIDString("gl_VertexID");
+
+class TBuiltinsWorkaroundGLSL : public TIntermTraverser
+{
+  public:
+    TBuiltinsWorkaroundGLSL(TSymbolTable *symbolTable, const ShCompileOptions &options);
+
+    void visitSymbol(TIntermSymbol *node) override;
+    bool visitDeclaration(Visit, TIntermDeclaration *node) override;
+
+  private:
+    void ensureVersionIsAtLeast(int version);
+
+    const ShCompileOptions &mCompileOptions;
+
+    bool isBaseInstanceDeclared = false;
+};
+
+TBuiltinsWorkaroundGLSL::TBuiltinsWorkaroundGLSL(TSymbolTable *symbolTable,
+                                                 const ShCompileOptions &options)
+    : TIntermTraverser(true, false, false, symbolTable), mCompileOptions(options)
+{}
+
+void TBuiltinsWorkaroundGLSL::visitSymbol(TIntermSymbol *node)
+{
+    if (node->variable().symbolType() == SymbolType::BuiltIn)
+    {
+        if (node->getName() == kGlInstanceIDString)
+        {
+            TIntermSymbol *instanceIndexRef =
+                new TIntermSymbol(BuiltInVariable::gl_InstanceIndex());
+
+            if (isBaseInstanceDeclared)
+            {
+                TIntermSymbol *baseInstanceRef =
+                    new TIntermSymbol(BuiltInVariable::angle_BaseInstance());
+
+                TIntermBinary *subBaseInstance =
+                    new TIntermBinary(EOpSub, instanceIndexRef, baseInstanceRef);
+                queueReplacement(subBaseInstance, OriginalNode::IS_DROPPED);
+            }
+            else
+            {
+                queueReplacement(instanceIndexRef, OriginalNode::IS_DROPPED);
+            }
+        }
+        else if (node->getName() == kGlVertexIDString)
+        {
+            TIntermSymbol *vertexIndexRef = new TIntermSymbol(BuiltInVariable::gl_VertexIndex());
+            queueReplacement(vertexIndexRef, OriginalNode::IS_DROPPED);
+        }
+    }
+}
+
+bool TBuiltinsWorkaroundGLSL::visitDeclaration(Visit, TIntermDeclaration *node)
+{
+    const TIntermSequence &sequence = *(node->getSequence());
+    ASSERT(!sequence.empty());
+
+    for (TIntermNode *variableNode : sequence)
+    {
+        TIntermSymbol *variable = variableNode->getAsSymbolNode();
+        if (variable && variable->variable().symbolType() == SymbolType::BuiltIn)
+        {
+            if (variable->getName() == "angle_BaseInstance")
+            {
+                isBaseInstanceDeclared = true;
+            }
+        }
+    }
+    return true;
+}
+
+}  // anonymous namespace
+
+[[nodiscard]] bool ShaderBuiltinsWorkaround(TCompiler *compiler,
+                                            TIntermBlock *root,
+                                            TSymbolTable *symbolTable,
+                                            const ShCompileOptions &compileOptions)
+{
+    TBuiltinsWorkaroundGLSL builtins(symbolTable, compileOptions);
+    root->traverse(&builtins);
+    if (!builtins.updateTree(compiler, root))
+    {
+        return false;
+    }
+    return true;
+}
+
+}  // namespace sh