Stub simplifying array assignment for HLSL output

src/compiler.gypi

@@ -153,6 +153,8 @@
             'compiler/translator/RemoveSwitchFallThrough.h',
             'compiler/translator/RewriteElseBlocks.cpp',
             'compiler/translator/RewriteElseBlocks.h',
+            'compiler/translator/SimplifyArrayAssignment.cpp',
+            'compiler/translator/SimplifyArrayAssignment.h',
             'compiler/translator/StructureHLSL.cpp',
             'compiler/translator/StructureHLSL.h',
             'compiler/translator/TranslatorHLSL.cpp',

src/compiler/translator/SimplifyArrayAssignment.cpp

+//
+// Copyright (c) 2002-2015 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/SimplifyArrayAssignment.h"
+
+bool SimplifyArrayAssignment::visitBinary(Visit visit, TIntermBinary *node)
+{
+    switch (node->getOp())
+    {
+      case EOpAssign:
+        {
+            TIntermNode *parent = getParentNode();
+            if (node->getLeft()->isArray() && parent != nullptr)
+            {
+                TIntermAggregate *parentAgg = parent->getAsAggregate();
+                if (parentAgg != nullptr && parentAgg->getOp() == EOpSequence)
+                {
+                    // This case is fine, the result of the assignment is not used.
+                    break;
+                }
+
+                // The result of the assignment needs to be stored into a temporary variable,
+                // the assignment needs to be replaced with a reference to the temporary variable,
+                // and the temporary variable needs to finally be assigned to the target variable.
+
+                // This also needs to interact correctly with unfolding short circuiting operators.
+                UNIMPLEMENTED();
+            }
+        }
+        break;
+      default:
+        break;
+    }
+    return true;
+}

src/compiler/translator/SimplifyArrayAssignment.h

+//
+// Copyright (c) 2002-2015 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.
+//
+// SimplifyArrayAssignment is an AST traverser to replace statements where
+// the return value of array assignment is used with statements where
+// the return value of array assignment is not used.
+//
+
+#ifndef COMPILER_TRANSLATOR_SIMPLIFYARRAYASSIGNMENT_H_
+#define COMPILER_TRANSLATOR_SIMPLIFYARRAYASSIGNMENT_H_
+
+#include "common/angleutils.h"
+#include "compiler/translator/IntermNode.h"
+
+class SimplifyArrayAssignment : public TIntermTraverser
+{
+  public:
+    SimplifyArrayAssignment() { }
+
+    virtual bool visitBinary(Visit visit, TIntermBinary *node);
+};
+
+#endif  // COMPILER_TRANSLATOR_SIMPLIFYARRAYASSIGNMENT_H_

src/compiler/translator/TranslatorHLSL.cpp

@@ -7,6 +7,7 @@
 #include "compiler/translator/TranslatorHLSL.h"
 
 #include "compiler/translator/OutputHLSL.h"
+#include "compiler/translator/SimplifyArrayAssignment.h"
 
 TranslatorHLSL::TranslatorHLSL(sh::GLenum type, ShShaderSpec spec, ShShaderOutput output)
     : TCompiler(type, spec, output)
@@ -18,6 +19,9 @@ void TranslatorHLSL::translate(TIntermNode *root, int compileOptions)
     const ShBuiltInResources &resources = getResources();
     int numRenderTargets = resources.EXT_draw_buffers ? resources.MaxDrawBuffers : 1;
 
+    SimplifyArrayAssignment simplify;
+    root->traverse(&simplify);
+
     sh::OutputHLSL outputHLSL(getShaderType(), getShaderVersion(), getExtensionBehavior(),
         getSourcePath(), getOutputType(), numRenderTargets, getUniforms(), compileOptions);