Incorporated BSD-licensed changes implementing array bounds clamping.

BUG=none
TEST=ran associated WebKit layout tests in Chromium
Review URL: https://codereview.appspot.com/6999052

git-svn-id: https://angleproject.googlecode.com/svn/branches/dx11proto@1701 736b8ea6-26fd-11df-bfd4-992fa37f6226

AUTHORS

@@ -12,6 +12,7 @@ TransGaming Inc.
 3DLabs Inc. Ltd.
 
 Adobe Systems Inc.
+Apple Inc.
 Autodesk, Inc.
 Cloud Party, Inc.
 Intel Corporation

include/GLSLANG/ShaderLang.h

@@ -151,7 +151,13 @@ typedef enum {
   SH_DEPENDENCY_GRAPH = 0x0400,
 
   // Enforce the GLSL 1.017 Appendix A section 7 packing restrictions.
-  SH_ENFORCE_PACKING_RESTRICTIONS = 0x0800
+  SH_ENFORCE_PACKING_RESTRICTIONS = 0x0800,
+
+  // This flag ensures all indirect (expression-based) array indexing
+  // is clamped to the bounds of the array. This ensures, for example,
+  // that you cannot read off the end of a uniform, whether an array
+  // vec234, or mat234 type.
+  SH_CLAMP_INDIRECT_ARRAY_BOUNDS = 0x1000
 } ShCompileOptions;
 
 //

src/build_angle.gypi

@@ -60,6 +60,8 @@
         'COMPILER_IMPLEMENTATION',
       ],
       'sources': [
+        'compiler/ArrayBoundsClamper.cpp',
+        'compiler/ArrayBoundsClamper.h',
         'compiler/BaseTypes.h',
         'compiler/BuiltInFunctionEmulator.cpp',
         'compiler/BuiltInFunctionEmulator.h',

src/compiler/ArrayBoundsClamper.cpp

@@ -0,0 +1,88 @@
+/*
+ * 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 "compiler/ArrayBoundsClamper.h"
+
+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 {
+
+class ArrayBoundsClamperMarker : public TIntermTraverser {
+public:
+    ArrayBoundsClamperMarker()
+        : mNeedsClamp(false)
+   {
+   }
+
+   virtual bool visitBinary(Visit visit, TIntermBinary* node)
+   {
+       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()
+    : mArrayBoundsClampDefinitionNeeded(false)
+{
+}
+
+void ArrayBoundsClamper::OutputClampingFunctionDefinition(TInfoSinkBase& out) const
+{
+    if (!mArrayBoundsClampDefinitionNeeded)
+    {
+        return;
+    }
+    out << kIntClampBegin << kIntClampDefinition << kIntClampEnd;
+}
+
+void ArrayBoundsClamper::MarkIndirectArrayBoundsForClamping(TIntermNode* root)
+{
+    ASSERT(root);
+
+    ArrayBoundsClamperMarker clamper;
+    root->traverse(&clamper);
+    if (clamper.GetNeedsClamp())
+    {
+        SetArrayBoundsClampDefinitionNeeded();
+    }
+}
+

src/compiler/ArrayBoundsClamper.h

@@ -0,0 +1,57 @@
+/*
+ * 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.
+ */
+
+#ifndef COMPILER_ARRAY_BOUNDS_CLAMPER_H_
+#define COMPILER_ARRAY_BOUNDS_CLAMPER_H_
+
+#include "GLSLANG/ShaderLang.h"
+
+#include "compiler/InfoSink.h"
+#include "compiler/intermediate.h"
+
+class ArrayBoundsClamper {
+public:
+    ArrayBoundsClamper();
+
+    // Output array clamp function source into the shader source.
+    void OutputClampingFunctionDefinition(TInfoSinkBase& out) const;
+
+    // Marks nodes in the tree that index arrays indirectly as
+    // requiring clamping.
+    void MarkIndirectArrayBoundsForClamping(TIntermNode* root);
+
+    void Cleanup()
+    {
+        mArrayBoundsClampDefinitionNeeded = false;
+    }
+
+private:
+    bool GetArrayBoundsClampDefinitionNeeded() const { return mArrayBoundsClampDefinitionNeeded; }
+    void SetArrayBoundsClampDefinitionNeeded() { mArrayBoundsClampDefinitionNeeded = true; }
+    
+    bool mArrayBoundsClampDefinitionNeeded;
+};
+
+#endif // COMPILER_ARRAY_BOUNDS_CLAMPER_H_

src/compiler/Compiler.cpp

@@ -4,6 +4,7 @@
 // found in the LICENSE file.
 //
 
+#include "compiler/ArrayBoundsClamper.h"
 #include "compiler/BuiltInFunctionEmulator.h"
 #include "compiler/DetectRecursion.h"
 #include "compiler/ForLoopUnroll.h"
@@ -192,6 +193,10 @@ bool TCompiler::compile(const char* const shaderStrings[],
         if (success && (compileOptions & SH_EMULATE_BUILT_IN_FUNCTIONS))
             builtInFunctionEmulator.MarkBuiltInFunctionsForEmulation(root);
 
+        // Clamping uniform array bounds needs to happen after validateLimitations pass.
+        if (success && (compileOptions & SH_CLAMP_INDIRECT_ARRAY_BOUNDS))
+            arrayBoundsClamper.MarkIndirectArrayBoundsForClamping(root);
+
         // Call mapLongVariableNames() before collectAttribsUniforms() so in
         // collectAttribsUniforms() we already have the mapped symbol names and
         // we could composite mapped and original variable names.
@@ -237,6 +242,7 @@ bool TCompiler::InitBuiltInSymbolTable(const ShBuiltInResources& resources)
 
 void TCompiler::clearResults()
 {
+    arrayBoundsClamper.Cleanup();
     infoSink.info.erase();
     infoSink.obj.erase();
     infoSink.debug.erase();
@@ -353,3 +359,9 @@ const BuiltInFunctionEmulator& TCompiler::getBuiltInFunctionEmulator() const
 {
     return builtInFunctionEmulator;
 }
+
+const ArrayBoundsClamper& TCompiler::getArrayBoundsClamper() const
+{
+    return arrayBoundsClamper;
+}
+

src/compiler/OutputGLSLBase.cpp

@@ -212,9 +212,38 @@ bool TOutputGLSLBase::visitBinary(Visit visit, TIntermBinary* node)
             break;
 
         case EOpIndexDirect:
-        case EOpIndexIndirect:
             writeTriplet(visit, NULL, "[", "]");
             break;
+        case EOpIndexIndirect:
+            if (node->getAddIndexClamp())
+            {
+                if (visit == InVisit)
+                {
+                    out << "[webgl_int_clamp(";
+                }
+                else if (visit == PostVisit)
+                {
+                    int maxSize;
+                    TIntermTyped *left = node->getLeft();
+                    TType leftType = left->getType();
+
+                    if (left->isArray())
+                    {
+                        // The shader will fail validation if the array length is not > 0.
+                        maxSize = leftType.getArraySize() - 1;
+                    }
+                    else
+                    {
+                        maxSize = leftType.getNominalSize() - 1;
+                    }
+                    out << ", 0, " << maxSize << ")]";
+                }
+            }
+            else
+            {
+                writeTriplet(visit, NULL, "[", "]");
+            }
+            break;
         case EOpIndexDirectStruct:
             if (visit == InVisit)
             {

src/compiler/ShHandle.h

@@ -16,6 +16,7 @@
 
 #include "GLSLANG/ShaderLang.h"
 
+#include "compiler/ArrayBoundsClamper.h"
 #include "compiler/BuiltInFunctionEmulator.h"
 #include "compiler/ExtensionBehavior.h"
 #include "compiler/HashNames.h"
@@ -108,6 +109,7 @@ protected:
     // Get built-in extensions with default behavior.
     const TExtensionBehavior& getExtensionBehavior() const;
 
+    const ArrayBoundsClamper& getArrayBoundsClamper() const;
     const BuiltInFunctionEmulator& getBuiltInFunctionEmulator() const;
 
 private:
@@ -122,6 +124,7 @@ private:
     // Built-in extensions with default behavior.
     TExtensionBehavior extensionBehavior;
 
+    ArrayBoundsClamper arrayBoundsClamper;
     BuiltInFunctionEmulator builtInFunctionEmulator;
 
     // Results of compilation.

src/compiler/TranslatorESSL.cpp

@@ -22,6 +22,9 @@ void TranslatorESSL::translate(TIntermNode* root) {
     getBuiltInFunctionEmulator().OutputEmulatedFunctionDefinition(
         sink, getShaderType() == SH_FRAGMENT_SHADER);
 
+    // Write array bounds clamping emulation if needed.
+    getArrayBoundsClamper().OutputClampingFunctionDefinition(sink);
+
     // Write translated shader.
     TOutputESSL outputESSL(sink, getHashFunction(), getNameMap(), getSymbolTable());
     root->traverse(&outputESSL);

src/compiler/TranslatorGLSL.cpp

@@ -35,6 +35,9 @@ void TranslatorGLSL::translate(TIntermNode* root) {
     getBuiltInFunctionEmulator().OutputEmulatedFunctionDefinition(
         sink, false);
 
+    // Write array bounds clamping emulation if needed.
+    getArrayBoundsClamper().OutputClampingFunctionDefinition(sink);
+
     // Write translated shader.
     TOutputGLSL outputGLSL(sink, getHashFunction(), getNameMap(), getSymbolTable());
     root->traverse(&outputGLSL);

src/compiler/intermOut.cpp

@@ -42,7 +42,7 @@ TString TType::getCompleteString() const
     if (qualifier != EvqTemporary && qualifier != EvqGlobal)
         stream << getQualifierString() << " " << getPrecisionString() << " ";
     if (array)
-        stream << "array of ";
+        stream << "array[" << getArraySize() << "] of ";
     if (matrix)
         stream << size << "X" << size << " matrix of ";
     else if (size > 1)

src/compiler/intermediate.h

@@ -395,7 +395,7 @@ protected:
 //
 class TIntermBinary : public TIntermOperator {
 public:
-    TIntermBinary(TOperator o) : TIntermOperator(o) {}
+    TIntermBinary(TOperator o) : TIntermOperator(o), addIndexClamp(false) {}
 
     virtual TIntermBinary* getAsBinaryNode() { return this; }
     virtual void traverse(TIntermTraverser*);
@@ -406,9 +406,15 @@ public:
     TIntermTyped* getRight() const { return right; }
     bool promote(TInfoSink&);
 
+    void setAddIndexClamp() { addIndexClamp = true; }
+    bool getAddIndexClamp() { return addIndexClamp; }
+
 protected:
     TIntermTyped* left;
     TIntermTyped* right;
+
+    // If set to true, wrap any EOpIndexIndirect with a clamp to bounds.
+    bool addIndexClamp;
 };
 
 //

src/compiler/translator_common.vcxproj

@@ -138,6 +138,7 @@
     </ClCompile>
   </ItemDefinitionGroup>
   <ItemGroup>
+    <ClCompile Include="ArrayBoundsClamper.cpp" />
     <ClCompile Include="BuiltInFunctionEmulator.cpp" />
     <ClCompile Include="Compiler.cpp" />
     <ClCompile Include="debug.cpp" />
@@ -225,6 +226,7 @@
     </CustomBuild>
   </ItemGroup>
   <ItemGroup>
+    <ClInclude Include="ArrayBoundsClamper.h" />
     <ClInclude Include="BaseTypes.h" />
     <ClInclude Include="BuiltInFunctionEmulator.h" />
     <ClInclude Include="Common.h" />
@@ -279,4 +281,4 @@
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
   </ImportGroup>
-</Project>
+</Project>