1 files changed, 112 insertions, 0 deletions
diff --git a/gfx/angle/checkout/src/third_party/compiler/ArrayBoundsClamper.cpp b/gfx/angle/checkout/src/third_party/compiler/ArrayBoundsClamper.cpp
new file mode 100644
index 0000000000..b9bd73418c
--- /dev/null
+++ b/gfx/angle/checkout/src/third_party/compiler/ArrayBoundsClamper.cpp
@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2012 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE, INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE, INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "third_party/compiler/ArrayBoundsClamper.h"
+
+#include "compiler/translator/tree_util/IntermTraverse.h"
+
+// The built-in 'clamp' instruction only accepts floats and returns a float.  I
+// iterated a few times with our driver team who examined the output from our
+// compiler - they said the multiple casts generates more code than a single
+// function call.  An inline ternary operator might have been better, but since
+// the index value might be an expression itself, we'd have to make temporary
+// variables to avoid evaluating the expression multiple times.  And making
+// temporary variables was difficult because ANGLE would then need to make more
+// brutal changes to the expression tree.
+
+const char *kIntClampBegin = "// BEGIN: Generated code for array bounds clamping\n\n";
+const char *kIntClampEnd   = "// END: Generated code for array bounds clamping\n\n";
+const char *kIntClampDefinition =
+    "int webgl_int_clamp(int value, int minValue, int maxValue) { return ((value < minValue) ? "
+    "minValue : ((value > maxValue) ? maxValue : value)); }\n\n";
+
+namespace sh
+{
+
+namespace
+{
+
+class ArrayBoundsClamperMarker : public TIntermTraverser
+{
+  public:
+    ArrayBoundsClamperMarker() : TIntermTraverser(true, false, false), mNeedsClamp(false) {}
+
+    bool visitBinary(Visit visit, TIntermBinary *node) override
+    {
+        if (node->getOp() == EOpIndexIndirect)
+        {
+            TIntermTyped *left = node->getLeft();
+            if (left->isArray() || left->isVector() || left->isMatrix())
+            {
+                node->setAddIndexClamp();
+                mNeedsClamp = true;
+            }
+        }
+        return true;
+    }
+
+    bool GetNeedsClamp() { return mNeedsClamp; }
+
+  private:
+    bool mNeedsClamp;
+};
+
+}  // anonymous namespace
+
+ArrayBoundsClamper::ArrayBoundsClamper()
+    : mClampingStrategy(SH_CLAMP_WITH_CLAMP_INTRINSIC), mArrayBoundsClampDefinitionNeeded(false)
+{}
+
+void ArrayBoundsClamper::SetClampingStrategy(ShArrayIndexClampingStrategy clampingStrategy)
+{
+    mClampingStrategy = clampingStrategy;
+}
+
+void ArrayBoundsClamper::MarkIndirectArrayBoundsForClamping(TIntermNode *root)
+{
+    ASSERT(root);
+
+    ArrayBoundsClamperMarker clamper;
+    root->traverse(&clamper);
+    if (clamper.GetNeedsClamp())
+    {
+        SetArrayBoundsClampDefinitionNeeded();
+    }
+}
+
+void ArrayBoundsClamper::OutputClampingFunctionDefinition(TInfoSinkBase &out) const
+{
+    if (!mArrayBoundsClampDefinitionNeeded)
+    {
+        return;
+    }
+    if (mClampingStrategy != SH_CLAMP_WITH_USER_DEFINED_INT_CLAMP_FUNCTION)
+    {
+        return;
+    }
+    out << kIntClampBegin << kIntClampDefinition << kIntClampEnd;
+}
+
+}  // namespace sh