Refactor TLiveTraverser from the former reflection traverser, for future use in binding mapping.

This PR factors out the code that knows how to walk just the live parts of the AST.
The traverser in reflect.cpp is renamed to TReflectionTraverser, and inherits from
TLiveTraverser, which will also be used by a future binding offset PR.

The code is now smart about the entry point name (no longer hardcoded to "main").

There is an option to traverse all code (live+dead), because a consumer of the
class may wish to use it for both purposes without wanting a whole separate
class hierarchy.

glslang/CMakeLists.txt

@@ -55,6 +55,7 @@ set(HEADERS
     MachineIndependent/glslang_tab.cpp.h
     MachineIndependent/gl_types.h
     MachineIndependent/Initialize.h
+    MachineIndependent/LiveTraverser.h
     MachineIndependent/localintermediate.h
     MachineIndependent/ParseHelper.h
     MachineIndependent/reflection.h

glslang/MachineIndependent/LiveTraverser.h

@@ -0,0 +1,134 @@
+//
+//Copyright (C) 2016 LunarG, 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:
+//
+//    Redistributions of source code must retain the above copyright
+//    notice, this list of conditions and the following disclaimer.
+//
+//    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.
+//
+//    Neither the name of 3Dlabs Inc. Ltd. nor the names of its
+//    contributors may be used to endorse or promote products derived
+//    from this software without specific prior written permission.
+//
+//THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+//"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 THE
+//COPYRIGHT HOLDERS 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 "../Include/Common.h"
+#include "reflection.h"
+#include "localintermediate.h"
+
+#include "gl_types.h"
+
+#include <list>
+#include <unordered_set>
+
+namespace glslang {
+
+//
+// The traverser: mostly pass through, except
+//  - processing function-call nodes to push live functions onto the stack of functions to process
+//  - processing selection nodes to trim semantically dead code
+//
+// This is in the glslang namespace directly so it can be a friend of TReflection.
+// This can be derived from to implement reflection database traversers or
+// binding mappers: anything that wants to traverse the live subset of the tree.
+//
+
+class TLiveTraverser : public TIntermTraverser {
+public:
+    TLiveTraverser(const TIntermediate& i, bool traverseAll = false) :
+        intermediate(i), traverseAll(traverseAll)
+    { }
+
+    //
+    // Given a function name, find its subroot in the tree, and push it onto the stack of
+    // functions left to process.
+    //
+    void pushFunction(const TString& name)
+    {
+        TIntermSequence& globals = intermediate.getTreeRoot()->getAsAggregate()->getSequence();
+        for (unsigned int f = 0; f < globals.size(); ++f) {
+            TIntermAggregate* candidate = globals[f]->getAsAggregate();
+            if (candidate && candidate->getOp() == EOpFunction && candidate->getName() == name) {
+                functions.push_back(candidate);
+                break;
+            }
+        }
+    }
+
+    typedef std::list<TIntermAggregate*> TFunctionStack;
+    TFunctionStack functions;
+
+protected:
+    // To catch which function calls are not dead, and hence which functions must be visited.
+    virtual bool visitAggregate(TVisit, TIntermAggregate* node)
+    {
+        if (!traverseAll)
+            if (node->getOp() == EOpFunctionCall)
+                addFunctionCall(node);
+
+        return true; // traverse this subtree
+    }
+
+    // To prune semantically dead paths.
+    virtual bool visitSelection(TVisit /* visit */,  TIntermSelection* node)
+    {
+        if (traverseAll)
+            return true; // traverse all code
+
+        TIntermConstantUnion* constant = node->getCondition()->getAsConstantUnion();
+        if (constant) {
+            // cull the path that is dead
+            if (constant->getConstArray()[0].getBConst() == true && node->getTrueBlock())
+                node->getTrueBlock()->traverse(this);
+            if (constant->getConstArray()[0].getBConst() == false && node->getFalseBlock())
+                node->getFalseBlock()->traverse(this);
+
+            return false; // don't traverse any more, we did it all above
+        } else
+            return true; // traverse the whole subtree
+    }
+
+    // Track live functions as well as uniforms, so that we don't visit dead functions
+    // and only visit each function once.
+    void addFunctionCall(TIntermAggregate* call)
+    {
+        // // just use the map to ensure we process each function at most once
+        if (liveFunctions.find(call->getName()) == liveFunctions.end()) {
+            liveFunctions.insert(call->getName());
+            pushFunction(call->getName());
+        }
+    }
+
+    const TIntermediate& intermediate;
+    typedef std::unordered_set<TString> TLiveFunctions;
+    TLiveFunctions liveFunctions;
+    bool traverseAll;
+
+private:
+    // prevent copy & copy construct
+    TLiveTraverser(TLiveTraverser&);
+    TLiveTraverser& operator=(TLiveTraverser&);
+};
+
+} // namespace glslang

glslang/MachineIndependent/reflection.cpp

@@ -1,5 +1,5 @@
 //
-//Copyright (C) 2013 LunarG, Inc.
+//Copyright (C) 2013-2016 LunarG, Inc.
 //
 //All rights reserved.
 //
@@ -35,6 +35,7 @@
 
 #include "../Include/Common.h"
 #include "reflection.h"
+#include "LiveTraverser.h"
 #include "localintermediate.h"
 
 #include "gl_types.h"
@@ -62,37 +63,26 @@
 // there wasn't exactly one entry point.
 //
 
+   
 namespace glslang {
 
 //
 // The traverser: mostly pass through, except
-//  - processing function-call nodes to push live functions onto the stack of functions to process
 //  - processing binary nodes to see if they are dereferences of an aggregates to track
 //  - processing symbol nodes to see if they are non-aggregate objects to track
-//  - processing selection nodes to trim semantically dead code
+//
+// This ignores semantically dead code by using TLiveTraverser.
 //
 // This is in the glslang namespace directly so it can be a friend of TReflection.
 //
 
-class TLiveTraverser : public TIntermTraverser {
+class TReflectionTraverser : public TLiveTraverser {
 public:
-    TLiveTraverser(const TIntermediate& i, TReflection& r) : intermediate(i), reflection(r) { }
+    TReflectionTraverser(const TIntermediate& i, TReflection& r) :
+         TLiveTraverser(i), reflection(r) { }
 
-    virtual bool visitAggregate(TVisit, TIntermAggregate* node);
     virtual bool visitBinary(TVisit, TIntermBinary* node);
     virtual void visitSymbol(TIntermSymbol* base);
-    virtual bool visitSelection(TVisit, TIntermSelection* node);
-
-    // Track live functions as well as uniforms, so that we don't visit dead functions
-    // and only visit each function once.
-    void addFunctionCall(TIntermAggregate* call)
-    {
-        // just use the map to ensure we process each function at most once
-        if (reflection.nameToIndex.find(call->getName()) == reflection.nameToIndex.end()) {
-            reflection.nameToIndex[call->getName()] = -1;
-            pushFunction(call->getName());
-        }
-    }
 
     // Add a simple reference to a uniform variable to the uniform database, no dereference involved.
     // However, no dereference doesn't mean simple... it could be a complex aggregate.
@@ -358,21 +348,6 @@ public:
         return blockIndex;
     }
 
-    //
-    // Given a function name, find its subroot in the tree, and push it onto the stack of
-    // functions left to process.
-    //
-    void pushFunction(const TString& name)
-    {
-        TIntermSequence& globals = intermediate.getTreeRoot()->getAsAggregate()->getSequence();
-        for (unsigned int f = 0; f < globals.size(); ++f) {
-            TIntermAggregate* candidate = globals[f]->getAsAggregate();
-            if (candidate && candidate->getOp() == EOpFunction && candidate->getName() == name) {
-                functions.push_back(candidate);
-                break;
-            }
-        }
-    }
 
     // Are we at a level in a dereference chain at which individual active uniform queries are made?
     bool isReflectionGranularity(const TType& type)
@@ -639,33 +614,21 @@ public:
         return type.isArray() ? type.getOuterArraySize() : 1;
     }
 
-    typedef std::list<TIntermAggregate*> TFunctionStack;
-    TFunctionStack functions;
-    const TIntermediate& intermediate;
     TReflection& reflection;
     std::set<const TIntermNode*> processedDerefs;
 
 protected:
-    TLiveTraverser(TLiveTraverser&);
+    TReflectionTraverser(TReflectionTraverser&);
-    TLiveTraverser& operator=(TLiveTraverser&);
+    TReflectionTraverser& operator=(TReflectionTraverser&);
 };
 
 //
 // Implement the traversal functions of interest.
 //
 
-// To catch which function calls are not dead, and hence which functions must be visited.
-bool TLiveTraverser::visitAggregate(TVisit /* visit */, TIntermAggregate* node)
-{
-    if (node->getOp() == EOpFunctionCall)
-        addFunctionCall(node);
-
-    return true; // traverse this subtree
-}
-
 // To catch dereferenced aggregates that must be reflected.
 // This catches them at the highest level possible in the tree.
-bool TLiveTraverser::visitBinary(TVisit /* visit */, TIntermBinary* node)
+bool TReflectionTraverser::visitBinary(TVisit /* visit */, TIntermBinary* node)
 {
     switch (node->getOp()) {
     case EOpIndexDirect:
@@ -683,7 +646,7 @@ bool TLiveTraverser::visitBinary(TVisit /* visit */, TIntermBinary* node)
 }
 
 // To reflect non-dereferenced objects.
-void TLiveTraverser::visitSymbol(TIntermSymbol* base)
+void TReflectionTraverser::visitSymbol(TIntermSymbol* base)
 {
     if (base->getQualifier().storage == EvqUniform)
         addUniform(*base);
@@ -692,21 +655,6 @@ void TLiveTraverser::visitSymbol(TIntermSymbol* base)
         addAttribute(*base);
 }
 
-// To prune semantically dead paths.
-bool TLiveTraverser::visitSelection(TVisit /* visit */,  TIntermSelection* node)
-{
-    TIntermConstantUnion* constant = node->getCondition()->getAsConstantUnion();
-    if (constant) {
-        // cull the path that is dead
-        if (constant->getConstArray()[0].getBConst() == true && node->getTrueBlock())
-            node->getTrueBlock()->traverse(this);
-        if (constant->getConstArray()[0].getBConst() == false && node->getFalseBlock())
-            node->getFalseBlock()->traverse(this);
-
-        return false; // don't traverse any more, we did it all above
-    } else
-        return true; // traverse the whole subtree
-}
 
 //
 // Implement TReflection methods.
@@ -720,7 +668,7 @@ bool TReflection::addStage(EShLanguage, const TIntermediate& intermediate)
     if (intermediate.getNumEntryPoints() != 1 || intermediate.isRecursive())
         return false;
 
-    TLiveTraverser it(intermediate, *this);
+    TReflectionTraverser it(intermediate, *this);
 
     // put the entry point on functions to process
     it.pushFunction("main(");

glslang/MachineIndependent/reflection.h

@@ -49,7 +49,7 @@ namespace glslang {
 
 class TIntermediate;
 class TIntermAggregate;
-class TLiveTraverser;
+class TReflectionTraverser;
 
 // Data needed for just a single object at the granularity exchanged by the reflection API
 class TObjectReflection {
@@ -116,7 +116,7 @@ public:
     void dump();
 
 protected:
-    friend class glslang::TLiveTraverser;
+    friend class glslang::TReflectionTraverser;
 
     // Need a TString hash: typedef std::unordered_map<TString, int> TNameToIndex;
     typedef std::map<TString, int> TNameToIndex;