Add expression complexity and call stack depth limits.

build/common.gypi

@@ -110,6 +110,10 @@
             'LinkIncremental': '2',
           },
         },
+        'xcode_settings': {
+          'COPY_PHASE_STRIP': 'NO',
+          'GCC_OPTIMIZATION_LEVEL': '0',
+        },
       },  # Debug
       'Release': {
         'inherit_from': ['Common'],

include/GLSLANG/ShaderLang.h

@@ -159,7 +159,13 @@ typedef enum {
   // vec234, or mat234 type. The ShArrayIndexClampingStrategy enum,
   // specified in the ShBuiltInResources when constructing the
   // compiler, selects the strategy for the clamping implementation.
-  SH_CLAMP_INDIRECT_ARRAY_BOUNDS = 0x1000
+  SH_CLAMP_INDIRECT_ARRAY_BOUNDS = 0x1000,
+
+  // This flag limits the complexity of an expression.
+  SH_LIMIT_EXPRESSION_COMPLEXITY = 0x2000,
+
+  // This flag limits the depth of the call stack.
+  SH_LIMIT_CALL_STACK_DEPTH = 0x4000,
 } ShCompileOptions;
 
 // Defines alternate strategies for implementing array index clamping.
@@ -222,6 +228,12 @@ typedef struct
     // Selects a strategy to use when implementing array index clamping.
     // Default is SH_CLAMP_WITH_CLAMP_INTRINSIC.
     ShArrayIndexClampingStrategy ArrayIndexClampingStrategy;
+
+    // The maximum complexity an expression can be.
+    int MaxExpressionComplexity;
+
+    // The maximum depth a call stack can be.
+    int MaxCallStackDepth;
 } ShBuiltInResources;
 
 //

src/build_angle.gypi

@@ -72,8 +72,8 @@
         'compiler/ConstantUnion.h',
         'compiler/debug.cpp',
         'compiler/debug.h',
-        'compiler/DetectRecursion.cpp',
-        'compiler/DetectRecursion.h',
+        'compiler/DetectCallDepth.cpp',
+        'compiler/DetectCallDepth.h',
         'compiler/Diagnostics.h',
         'compiler/Diagnostics.cpp',
         'compiler/DirectiveHandler.h',

src/compiler/Compiler.cpp

@@ -5,7 +5,7 @@
 //
 
 #include "compiler/BuiltInFunctionEmulator.h"
-#include "compiler/DetectRecursion.h"
+#include "compiler/DetectCallDepth.h"
 #include "compiler/ForLoopUnroll.h"
 #include "compiler/Initialize.h"
 #include "compiler/InitializeParseContext.h"
@@ -104,6 +104,9 @@ TShHandleBase::~TShHandleBase() {
 TCompiler::TCompiler(ShShaderType type, ShShaderSpec spec)
     : shaderType(type),
       shaderSpec(spec),
+      maxUniformVectors(0),
+      maxExpressionComplexity(0),
+      maxCallStackDepth(0),
       fragmentPrecisionHigh(false),
       clampingStrategy(SH_CLAMP_WITH_CLAMP_INTRINSIC),
       builtInFunctionEmulator(type)
@@ -122,6 +125,8 @@ bool TCompiler::Init(const ShBuiltInResources& resources)
     maxUniformVectors = (shaderType == SH_VERTEX_SHADER) ?
         resources.MaxVertexUniformVectors :
         resources.MaxFragmentUniformVectors;
+    maxExpressionComplexity = resources.MaxExpressionComplexity;
+    maxCallStackDepth = resources.MaxCallStackDepth;
     TScopedPoolAllocator scopedAlloc(&allocator, false);
 
     // Generate built-in symbol table.
@@ -185,7 +190,7 @@ bool TCompiler::compile(const char* const shaderStrings[],
         success = intermediate.postProcess(root);
 
         if (success)
-            success = detectRecursion(root);
+            success = detectCallDepth(root, infoSink, (compileOptions & SH_LIMIT_CALL_STACK_DEPTH) != 0);
 
         if (success && (compileOptions & SH_VALIDATE_LOOP_INDEXING))
             success = validateLimitations(root);
@@ -208,6 +213,10 @@ bool TCompiler::compile(const char* const shaderStrings[],
         if (success && (compileOptions & SH_CLAMP_INDIRECT_ARRAY_BOUNDS))
             arrayBoundsClamper.MarkIndirectArrayBoundsForClamping(root);
 
+        // Disallow expressions deemed too complex.
+        if (success && (compileOptions & SH_LIMIT_EXPRESSION_COMPLEXITY))
+            success = limitExpressionComplexity(root);
+
         // Call mapLongVariableNames() before collectAttribsUniforms() so in
         // collectAttribsUniforms() we already have the mapped symbol names and
         // we could composite mapped and original variable names.
@@ -267,24 +276,27 @@ void TCompiler::clearResults()
     nameMap.clear();
 }
 
-bool TCompiler::detectRecursion(TIntermNode* root)
+bool TCompiler::detectCallDepth(TIntermNode* root, TInfoSink& infoSink, bool limitCallStackDepth)
 {
-    DetectRecursion detect;
+    DetectCallDepth detect(infoSink, limitCallStackDepth, maxCallStackDepth);
     root->traverse(&detect);
-    switch (detect.detectRecursion()) {
-        case DetectRecursion::kErrorNone:
+    switch (detect.detectCallDepth()) {
+        case DetectCallDepth::kErrorNone:
             return true;
-        case DetectRecursion::kErrorMissingMain:
+        case DetectCallDepth::kErrorMissingMain:
             infoSink.info.prefix(EPrefixError);
             infoSink.info << "Missing main()";
             return false;
-        case DetectRecursion::kErrorRecursion:
+        case DetectCallDepth::kErrorRecursion:
             infoSink.info.prefix(EPrefixError);
             infoSink.info << "Function recursion detected";
             return false;
+        case DetectCallDepth::kErrorMaxDepthExceeded:
+            infoSink.info.prefix(EPrefixError);
+            infoSink.info << "Function call stack too deep";
+            return false;
         default:
             UNREACHABLE();
-            return false;
     }
 }
 
@@ -326,6 +338,28 @@ bool TCompiler::enforceTimingRestrictions(TIntermNode* root, bool outputGraph)
     }
 }
 
+bool TCompiler::limitExpressionComplexity(TIntermNode* root)
+{
+    TIntermTraverser traverser;
+    root->traverse(&traverser);
+    TDependencyGraph graph(root);
+
+    for (TFunctionCallVector::const_iterator iter = graph.beginUserDefinedFunctionCalls();
+         iter != graph.endUserDefinedFunctionCalls();
+         ++iter)
+    {
+        TGraphFunctionCall* samplerSymbol = *iter;
+        TDependencyGraphTraverser graphTraverser;
+        samplerSymbol->traverse(&graphTraverser);
+    }
+
+    if (traverser.getMaxDepth() > maxExpressionComplexity) {
+        infoSink.info << "Expression too complex.";
+        return false;
+    }
+    return true;
+}
+
 bool TCompiler::enforceFragmentShaderTimingRestrictions(const TDependencyGraph& graph)
 {
     RestrictFragmentShaderTiming restrictor(infoSink.info);

src/compiler/DetectRecursion.cpp → src/compiler/DetectCallDepth.cpp

@@ -4,21 +4,24 @@
 // found in the LICENSE file.
 //
 
-#include "compiler/DetectRecursion.h"
+#include "compiler/DetectCallDepth.h"
+#include "compiler/InfoSink.h"
 
-DetectRecursion::FunctionNode::FunctionNode(const TString& fname)
+const int DetectCallDepth::FunctionNode::kInfiniteCallDepth;
+
+DetectCallDepth::FunctionNode::FunctionNode(const TString& fname)
     : name(fname),
       visit(PreVisit)
 {
 }
 
-const TString& DetectRecursion::FunctionNode::getName() const
+const TString& DetectCallDepth::FunctionNode::getName() const
 {
     return name;
 }
 
-void DetectRecursion::FunctionNode::addCallee(
-    DetectRecursion::FunctionNode* callee)
+void DetectCallDepth::FunctionNode::addCallee(
+    DetectCallDepth::FunctionNode* callee)
 {
     for (size_t i = 0; i < callees.size(); ++i) {
         if (callees[i] == callee)
@@ -27,21 +30,31 @@ void DetectRecursion::FunctionNode::addCallee(
     callees.push_back(callee);
 }
 
-bool DetectRecursion::FunctionNode::detectRecursion()
+int DetectCallDepth::FunctionNode::detectCallDepth(DetectCallDepth* detectCallDepth, int depth)
 {
     ASSERT(visit == PreVisit);
+    ASSERT(detectCallDepth);
+
+    int maxDepth = depth;
     visit = InVisit;
     for (size_t i = 0; i < callees.size(); ++i) {
         switch (callees[i]->visit) {
             case InVisit:
                 // cycle detected, i.e., recursion detected.
-                return true;
+                return kInfiniteCallDepth;
             case PostVisit:
                 break;
             case PreVisit: {
-                bool recursion = callees[i]->detectRecursion();
-                if (recursion)
-                    return true;
+                // Check before we recurse so we don't go too depth
+                if (detectCallDepth->checkExceedsMaxDepth(depth))
+                    return depth;
+                int callDepth = callees[i]->detectCallDepth(detectCallDepth, depth + 1);
+                // Check after we recurse so we can exit immediately and provide info.
+                if (detectCallDepth->checkExceedsMaxDepth(callDepth)) {
+                    detectCallDepth->getInfoSink().info << "<-" << callees[i]->getName();
+                    return callDepth;
+                }
+                maxDepth = std::max(callDepth, maxDepth);
                 break;
             }
             default:
@@ -50,21 +63,29 @@ bool DetectRecursion::FunctionNode::detectRecursion()
         }
     }
     visit = PostVisit;
-    return false;
+    return maxDepth;
 }
 
-DetectRecursion::DetectRecursion()
-    : currentFunction(NULL)
+void DetectCallDepth::FunctionNode::reset()
 {
+    visit = PreVisit;
 }
 
-DetectRecursion::~DetectRecursion()
+DetectCallDepth::DetectCallDepth(TInfoSink& infoSink, bool limitCallStackDepth, int maxCallStackDepth)
+    : TIntermTraverser(true, false, true, false),
+      currentFunction(NULL),
+      infoSink(infoSink),
+      maxDepth(limitCallStackDepth ? maxCallStackDepth : FunctionNode::kInfiniteCallDepth)
+{
+}
+
+DetectCallDepth::~DetectCallDepth()
 {
     for (size_t i = 0; i < functions.size(); ++i)
         delete functions[i];
 }
 
-bool DetectRecursion::visitAggregate(Visit visit, TIntermAggregate* node)
+bool DetectCallDepth::visitAggregate(Visit visit, TIntermAggregate* node)
 {
     switch (node->getOp())
     {
@@ -81,19 +102,21 @@ bool DetectRecursion::visitAggregate(Visit visit, TIntermAggregate* node)
                     currentFunction = new FunctionNode(node->getName());
                     functions.push_back(currentFunction);
                 }
+            } else if (visit == PostVisit) {
+                currentFunction = NULL;
             }
             break;
         }
         case EOpFunctionCall: {
             // Function call.
             if (visit == PreVisit) {
-                ASSERT(currentFunction != NULL);
                 FunctionNode* func = findFunctionByName(node->getName());
                 if (func == NULL) {
                     func = new FunctionNode(node->getName());
                     functions.push_back(func);
                 }
-                currentFunction->addCallee(func);
+                if (currentFunction)
+                    currentFunction->addCallee(func);
             }
             break;
         }
@@ -103,17 +126,56 @@ bool DetectRecursion::visitAggregate(Visit visit, TIntermAggregate* node)
     return true;
 }
 
-DetectRecursion::ErrorCode DetectRecursion::detectRecursion()
+bool DetectCallDepth::checkExceedsMaxDepth(int depth)
+{
+    return depth >= maxDepth;
+}
+
+void DetectCallDepth::resetFunctionNodes()
+{
+    for (size_t i = 0; i < functions.size(); ++i) {
+        functions[i]->reset();
+    }
+}
+
+DetectCallDepth::ErrorCode DetectCallDepth::detectCallDepthForFunction(FunctionNode* func)
 {
-    FunctionNode* main = findFunctionByName("main(");
-    if (main == NULL)
-        return kErrorMissingMain;
-    if (main->detectRecursion())
+    currentFunction = NULL;
+    resetFunctionNodes();
+
+    int maxCallDepth = func->detectCallDepth(this, 1);
+
+    if (maxCallDepth == FunctionNode::kInfiniteCallDepth)
         return kErrorRecursion;
+
+    if (maxCallDepth >= maxDepth)
+        return kErrorMaxDepthExceeded;
+
+    return kErrorNone;
+}
+
+DetectCallDepth::ErrorCode DetectCallDepth::detectCallDepth()
+{
+    if (maxDepth != FunctionNode::kInfiniteCallDepth) {
+        // Check all functions because the driver may fail on them
+        // TODO: Before detectingRecursion, strip unused functions.
+        for (size_t i = 0; i < functions.size(); ++i) {
+            ErrorCode error = detectCallDepthForFunction(functions[i]);
+            if (error != kErrorNone)
+                return error;
+        }
+    } else {
+        FunctionNode* main = findFunctionByName("main(");
+        if (main == NULL)
+            return kErrorMissingMain;
+
+        return detectCallDepthForFunction(main);
+    }
+
     return kErrorNone;
 }
 
-DetectRecursion::FunctionNode* DetectRecursion::findFunctionByName(
+DetectCallDepth::FunctionNode* DetectCallDepth::findFunctionByName(
     const TString& name)
 {
     for (size_t i = 0; i < functions.size(); ++i) {

src/compiler/DetectRecursion.h → src/compiler/DetectCallDepth.h

@@ -9,28 +9,36 @@
 
 #include "GLSLANG/ShaderLang.h"
 
+#include <limits.h>
 #include "compiler/intermediate.h"
 #include "compiler/VariableInfo.h"
 
+class TInfoSink;
+
 // Traverses intermediate tree to detect function recursion.
-class DetectRecursion : public TIntermTraverser {
+class DetectCallDepth : public TIntermTraverser {
 public:
     enum ErrorCode {
         kErrorMissingMain,
         kErrorRecursion,
+        kErrorMaxDepthExceeded,
         kErrorNone
     };
 
-    DetectRecursion();
-    ~DetectRecursion();
+    DetectCallDepth(TInfoSink& infoSync, bool limitCallStackDepth, int maxCallStackDepth);
+    ~DetectCallDepth();
 
     virtual bool visitAggregate(Visit, TIntermAggregate*);
 
-    ErrorCode detectRecursion();
+    bool checkExceedsMaxDepth(int depth);
+
+    ErrorCode detectCallDepth();
 
 private:
     class FunctionNode {
     public:
+        static const int kInfiniteCallDepth = INT_MAX;
+
         FunctionNode(const TString& fname);
 
         const TString& getName() const;
@@ -38,8 +46,11 @@ private:
         // If a function is already in the callee list, this becomes a no-op.
         void addCallee(FunctionNode* callee);
 
-        // Return true if recursive function calls are detected.
-        bool detectRecursion();
+        // Returns kInifinityCallDepth if recursive function calls are detected.
+        int detectCallDepth(DetectCallDepth* detectCallDepth, int depth);
+
+        // Reset state.
+        void reset();
 
     private:
         // mangled function name is unique.
@@ -51,10 +62,19 @@ private:
         Visit visit;
     };
 
+    ErrorCode detectCallDepthForFunction(FunctionNode* func);
     FunctionNode* findFunctionByName(const TString& name);
+    void resetFunctionNodes();
+
+    TInfoSink& getInfoSink() { return infoSink; }
 
     TVector<FunctionNode*> functions;
     FunctionNode* currentFunction;
+    TInfoSink& infoSink;
+    int maxDepth;
+
+    DetectCallDepth(const DetectCallDepth&);
+    void operator=(const DetectCallDepth&);
 };
 
 #endif  // COMPILER_DETECT_RECURSION_H_

src/compiler/ShHandle.h

@@ -81,8 +81,8 @@ protected:
     bool InitBuiltInSymbolTable(const ShBuiltInResources& resources);
     // Clears the results from the previous compilation.
     void clearResults();
-    // Return true if function recursion is detected.
-    bool detectRecursion(TIntermNode* root);
+    // Return true if function recursion is detected or call depth exceeded.
+    bool detectCallDepth(TIntermNode* root, TInfoSink& infoSink, bool limitCallStackDepth);
     // Rewrites a shader's intermediate tree according to the CSS Shaders spec.
     void rewriteCSSShader(TIntermNode* root);
     // Returns true if the given shader does not exceed the minimum
@@ -104,6 +104,8 @@ protected:
     // Returns true if the shader does not use sampler dependent values to affect control 
     // flow or in operations whose time can depend on the input values.
     bool enforceFragmentShaderTimingRestrictions(const TDependencyGraph& graph);
+    // Return true if the maximum expression complexity below the limit.
+    bool limitExpressionComplexity(TIntermNode* root);
     // Get built-in extensions with default behavior.
     const TExtensionBehavior& getExtensionBehavior() const;
 
@@ -116,6 +118,8 @@ private:
     ShShaderSpec shaderSpec;
 
     int maxUniformVectors;
+    int maxExpressionComplexity;
+    int maxCallStackDepth;
 
     // Built-in symbol table for the given language, spec, and resources.
     // It is preserved from compile-to-compile.

src/compiler/intermediate.h

@@ -18,6 +18,7 @@
 
 #include "GLSLANG/ShaderLang.h"
 
+#include <algorithm>
 #include "compiler/Common.h"
 #include "compiler/Types.h"
 #include "compiler/ConstantUnion.h"
@@ -542,7 +543,8 @@ public:
             inVisit(inVisit),
             postVisit(postVisit),
             rightToLeft(rightToLeft),
-            depth(0) {}
+            depth(0),
+            maxDepth(0) {}
     virtual ~TIntermTraverser() {};
 
     virtual void visitSymbol(TIntermSymbol*) {}
@@ -554,7 +556,8 @@ public:
     virtual bool visitLoop(Visit visit, TIntermLoop*) {return true;}
     virtual bool visitBranch(Visit visit, TIntermBranch*) {return true;}
 
-    void incrementDepth() {depth++;}
+    int getMaxDepth() const {return maxDepth;}
+    void incrementDepth() {depth++; maxDepth = std::max(maxDepth, depth); }
     void decrementDepth() {depth--;}
 
     // Return the original name if hash function pointer is NULL;
@@ -568,6 +571,7 @@ public:
 
 protected:
     int depth;
+    int maxDepth;
 };
 
 #endif // __INTERMEDIATE_H

src/compiler/translator_common.vcxproj

@@ -141,7 +141,7 @@
     <ClCompile Include="BuiltInFunctionEmulator.cpp" />
     <ClCompile Include="Compiler.cpp" />
     <ClCompile Include="debug.cpp" />
-    <ClCompile Include="DetectRecursion.cpp" />
+    <ClCompile Include="DetectCallDepth.cpp" />
     <ClCompile Include="Diagnostics.cpp" />
     <ClCompile Include="DirectiveHandler.cpp" />
     <ClCompile Include="ForLoopUnroll.cpp" />
@@ -231,7 +231,7 @@
     <ClInclude Include="Common.h" />
     <ClInclude Include="ConstantUnion.h" />
     <ClInclude Include="debug.h" />
-    <ClInclude Include="DetectRecursion.h" />
+    <ClInclude Include="DetectCallDepth.h" />
     <ClInclude Include="Diagnostics.h" />
     <ClInclude Include="DirectiveHandler.h" />
     <ClInclude Include="ForLoopUnroll.h" />

src/compiler/translator_common.vcxproj.filters

@@ -38,7 +38,7 @@
     <ClCompile Include="debug.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
-    <ClCompile Include="DetectRecursion.cpp">
+    <ClCompile Include="DetectCallDepth.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
     <ClCompile Include="Diagnostics.cpp">
@@ -151,7 +151,7 @@
     <ClInclude Include="debug.h">
       <Filter>Header Files</Filter>
     </ClInclude>
-    <ClInclude Include="DetectRecursion.h">
+    <ClInclude Include="DetectCallDepth.h">
       <Filter>Header Files</Filter>
     </ClInclude>
     <ClInclude Include="Diagnostics.h">

tests/build_tests.gyp

@@ -67,7 +67,7 @@
       'target_name': 'compiler_tests',
       'type': 'executable',
       'dependencies': [
-        '../src/build_angle.gyp:translator_common',
+        '../src/build_angle.gyp:translator_glsl',
         'gtest',
         'gmock',
       ],
@@ -79,6 +79,7 @@
       ],
       'sources': [
         '../third_party/googlemock/src/gmock_main.cc',
+        'compiler_tests/ExpressionLimit_test.cpp',
         'compiler_tests/VariablePacker_test.cpp',
       ],
     },