Refactoring: make tracking parent block position in AST traversal reusable

src/compiler/translator/IntermNode.h

@@ -629,6 +629,10 @@ class TIntermTraverser : angle::NonCopyable
         return mPath.size() == 0 ? NULL : mPath.back();
     }
 
+    void pushParentBlock(TIntermAggregate *node);
+    void incrementParentBlockPos();
+    void popParentBlock();
+
     // Return the original name if hash function pointer is NULL;
     // otherwise return the hashed name.
     static TString hash(const TString& name, ShHashFunction64 hashFunction);
@@ -704,6 +708,28 @@ class TIntermTraverser : angle::NonCopyable
     std::vector<NodeUpdateEntry> mReplacements;
     std::vector<NodeReplaceWithMultipleEntry> mMultiReplacements;
     std::vector<NodeInsertMultipleEntry> mInsertions;
+
+    // Helper to insert statements in the parent block (sequence) of the node currently being traversed.
+    // The statements will be inserted before the node being traversed once updateTree is called.
+    // Should only be called during PreVisit or PostVisit from sequence nodes.
+    // Note that inserting more than one set of nodes to the same parent node on a single updateTree call is not
+    // supported.
+    void insertStatementsInParentBlock(const TIntermSequence &insertions);
+
+  private:
+    struct ParentBlock
+    {
+        ParentBlock(TIntermAggregate *nodeIn, TIntermSequence::size_type posIn)
+            : node(nodeIn),
+              pos(posIn)
+        {
+        }
+
+        TIntermAggregate *node;
+        TIntermSequence::size_type pos;
+    };
+    // All the code blocks from the root to the current node's parent during traversal.
+    std::vector<ParentBlock> mParentBlockStack;
 };
 
 //

src/compiler/translator/IntermTraverse.cpp

@@ -6,6 +6,35 @@
 
 #include "compiler/translator/IntermNode.h"
 
+void TIntermTraverser::pushParentBlock(TIntermAggregate *node)
+{
+    if (rightToLeft)
+        mParentBlockStack.push_back(ParentBlock(node, node->getSequence()->size() - 1));
+    else
+        mParentBlockStack.push_back(ParentBlock(node, 0));
+}
+
+void TIntermTraverser::incrementParentBlockPos()
+{
+    if (rightToLeft)
+        --mParentBlockStack.back().pos;
+    else
+        ++mParentBlockStack.back().pos;
+}
+
+void TIntermTraverser::popParentBlock()
+{
+    ASSERT(!mParentBlockStack.empty());
+    mParentBlockStack.pop_back();
+}
+
+void TIntermTraverser::insertStatementsInParentBlock(const TIntermSequence &insertions)
+{
+    ASSERT(!mParentBlockStack.empty());
+    NodeInsertMultipleEntry insert(mParentBlockStack.back().node, mParentBlockStack.back().pos, insertions);
+    mInsertions.push_back(insert);
+}
+
 //
 // Traverse the intermediate representation tree, and
 // call a node type specific function for each node.
@@ -119,6 +148,9 @@ void TIntermAggregate::traverse(TIntermTraverser *it)
 
     if (visit)
     {
+        if (mOp == EOpSequence)
+            it->pushParentBlock(this);
+
         it->incrementDepth(this);
 
         if (it->rightToLeft)
@@ -133,6 +165,10 @@ void TIntermAggregate::traverse(TIntermTraverser *it)
                     if (*sit != mSequence.front())
                         visit = it->visitAggregate(InVisit, this);
                 }
+                if (mOp == EOpSequence)
+                {
+                    it->incrementParentBlockPos();
+                }
             }
         }
         else
@@ -147,10 +183,17 @@ void TIntermAggregate::traverse(TIntermTraverser *it)
                     if (*sit != mSequence.back())
                         visit = it->visitAggregate(InVisit, this);
                 }
+                if (mOp == EOpSequence)
+                {
+                    it->incrementParentBlockPos();
+                }
             }
         }
 
         it->decrementDepth();
+
+        if (mOp == EOpSequence)
+            it->popParentBlock();
     }
 
     if (visit && it->postVisit)

src/compiler/translator/UnfoldShortCircuitToIf.cpp

@@ -37,19 +37,6 @@ class UnfoldShortCircuitTraverser : public TIntermTraverser
     // After that, no more unfolding is performed on that traversal.
     bool mFoundShortCircuit;
 
-    struct ParentBlock
-    {
-        ParentBlock(TIntermAggregate *_node, TIntermSequence::size_type _pos)
-            : node(_node),
-              pos(_pos)
-        {
-        }
-
-        TIntermAggregate *node;
-        TIntermSequence::size_type pos;
-    };
-    std::vector<ParentBlock> mParentBlockStack;
-
     TIntermSymbol *createTempSymbol(const TType &type);
     TIntermAggregate *createTempInitDeclaration(const TType &type, TIntermTyped *initializer);
     TIntermBinary *createTempAssignment(const TType &type, TIntermTyped *rightNode);
@@ -131,8 +118,7 @@ bool UnfoldShortCircuitTraverser::visitBinary(Visit visit, TIntermBinary *node)
             TIntermSelection *ifNode = new TIntermSelection(notTempSymbol, assignRightBlock, nullptr);
             insertions.push_back(ifNode);
 
-            NodeInsertMultipleEntry insert(mParentBlockStack.back().node, mParentBlockStack.back().pos, insertions);
-            mInsertions.push_back(insert);
+            insertStatementsInParentBlock(insertions);
 
             NodeUpdateEntry replaceVariable(getParentNode(), node, createTempSymbol(boolType), false);
             mReplacements.push_back(replaceVariable);
@@ -155,8 +141,7 @@ bool UnfoldShortCircuitTraverser::visitBinary(Visit visit, TIntermBinary *node)
             TIntermSelection *ifNode = new TIntermSelection(createTempSymbol(boolType), assignRightBlock, nullptr);
             insertions.push_back(ifNode);
 
-            NodeInsertMultipleEntry insert(mParentBlockStack.back().node, mParentBlockStack.back().pos, insertions);
-            mInsertions.push_back(insert);
+            insertStatementsInParentBlock(insertions);
 
             NodeUpdateEntry replaceVariable(getParentNode(), node, createTempSymbol(boolType), false);
             mReplacements.push_back(replaceVariable);
@@ -194,8 +179,7 @@ bool UnfoldShortCircuitTraverser::visitSelection(Visit visit, TIntermSelection *
         TIntermSelection *ifNode = new TIntermSelection(node->getCondition()->getAsTyped(), trueBlock, falseBlock);
         insertions.push_back(ifNode);
 
-        NodeInsertMultipleEntry insert(mParentBlockStack.back().node, mParentBlockStack.back().pos, insertions);
-        mInsertions.push_back(insert);
+        insertStatementsInParentBlock(insertions);
 
         TIntermSymbol *ternaryResult = createTempSymbol(node->getType());
         NodeUpdateEntry replaceVariable(getParentNode(), node, ternaryResult, false);
@@ -211,23 +195,7 @@ bool UnfoldShortCircuitTraverser::visitAggregate(Visit visit, TIntermAggregate *
     if (visit == PreVisit && mFoundShortCircuit)
         return false; // No need to traverse further
 
-    if (node->getOp() == EOpSequence)
-    {
-        if (visit == PreVisit)
-        {
-            mParentBlockStack.push_back(ParentBlock(node, 0));
-        }
-        else if (visit == InVisit)
-        {
-            ++mParentBlockStack.back().pos;
-        }
-        else
-        {
-            ASSERT(visit == PostVisit);
-            mParentBlockStack.pop_back();
-        }
-    }
-    else if (node->getOp() == EOpComma)
+    if (node->getOp() == EOpComma)
     {
         ASSERT(visit != PreVisit || !mFoundShortCircuit);
 
@@ -255,8 +223,8 @@ bool UnfoldShortCircuitTraverser::visitAggregate(Visit visit, TIntermAggregate *
                 ++i;
             }
 
-            NodeInsertMultipleEntry insert(mParentBlockStack.back().node, mParentBlockStack.back().pos, insertions);
-            mInsertions.push_back(insert);
+            insertStatementsInParentBlock(insertions);
+
             NodeUpdateEntry replaceVariable(getParentNode(), node, (*seq)[i], false);
             mReplacements.push_back(replaceVariable);
         }