1 files changed, 132 insertions, 0 deletions
diff --git a/chromium/third_party/angle/src/compiler/translator/RewriteElseBlocks.cpp b/chromium/third_party/angle/src/compiler/translator/RewriteElseBlocks.cpp
new file mode 100644
index 00000000000..46e510c31b9
--- /dev/null
+++ b/chromium/third_party/angle/src/compiler/translator/RewriteElseBlocks.cpp
@@ -0,0 +1,132 @@
+//
+// Copyright (c) 2014 The ANGLE Project Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// RewriteElseBlocks.cpp: Implementation for tree transform to change
+//   all if-else blocks to if-if blocks.
+//
+
+#include "compiler/translator/RewriteElseBlocks.h"
+#include "compiler/translator/NodeSearch.h"
+#include "compiler/translator/SymbolTable.h"
+
+namespace sh
+{
+
+TIntermSymbol *MakeNewTemporary(const TString &name, TBasicType type)
+{
+    TType variableType(type, EbpHigh, EvqInternal);
+    return new TIntermSymbol(-1, name, variableType);
+}
+
+TIntermBinary *MakeNewBinary(TOperator op, TIntermTyped *left, TIntermTyped *right, const TType &resultType)
+{
+    TIntermBinary *binary = new TIntermBinary(op);
+    binary->setLeft(left);
+    binary->setRight(right);
+    binary->setType(resultType);
+    return binary;
+}
+
+TIntermUnary *MakeNewUnary(TOperator op, TIntermTyped *operand)
+{
+    TIntermUnary *unary = new TIntermUnary(op, operand->getType());
+    unary->setOperand(operand);
+    return unary;
+}
+
+ElseBlockRewriter::ElseBlockRewriter()
+    : TIntermTraverser(true, false, true, false),
+      mTemporaryIndex(0),
+      mFunctionType(NULL)
+{}
+
+bool ElseBlockRewriter::visitAggregate(Visit visit, TIntermAggregate *node)
+{
+    switch (node->getOp())
+    {
+      case EOpSequence:
+        if (visit == PostVisit)
+        {
+            for (size_t statementIndex = 0; statementIndex != node->getSequence().size(); statementIndex++)
+            {
+                TIntermNode *statement = node->getSequence()[statementIndex];
+                TIntermSelection *selection = statement->getAsSelectionNode();
+                if (selection && selection->getFalseBlock() != NULL)
+                {
+                    // Check for if / else if
+                    TIntermSelection *elseIfBranch = selection->getFalseBlock()->getAsSelectionNode();
+                    if (elseIfBranch)
+                    {
+                        selection->replaceChildNode(elseIfBranch, rewriteSelection(elseIfBranch));
+                        delete elseIfBranch;
+                    }
+
+                    node->getSequence()[statementIndex] = rewriteSelection(selection);
+                    delete selection;
+                }
+            }
+        }
+        break;
+
+      case EOpFunction:
+        // Store the current function context (see comment below)
+        mFunctionType = ((visit == PreVisit) ? &node->getType() : NULL);
+        break;
+
+      default: break;
+    }
+
+    return true;
+}
+
+TIntermNode *ElseBlockRewriter::rewriteSelection(TIntermSelection *selection)
+{
+    ASSERT(selection->getFalseBlock() != NULL);
+
+    TString temporaryName = "cond_" + str(mTemporaryIndex++);
+    TIntermTyped *typedCondition = selection->getCondition()->getAsTyped();
+    TType resultType(EbtBool, EbpUndefined);
+    TIntermSymbol *conditionSymbolA = MakeNewTemporary(temporaryName, EbtBool);
+    TIntermSymbol *conditionSymbolB = MakeNewTemporary(temporaryName, EbtBool);
+    TIntermSymbol *conditionSymbolC = MakeNewTemporary(temporaryName, EbtBool);
+    TIntermBinary *storeCondition = MakeNewBinary(EOpInitialize, conditionSymbolA,
+                                                  typedCondition, resultType);
+    TIntermUnary *negatedCondition = MakeNewUnary(EOpLogicalNot, conditionSymbolB);
+    TIntermNode *negatedElse = NULL;
+
+    // crbug.com/346463
+    // D3D generates error messages claiming a function has no return value, when rewriting
+    // an if-else clause that returns something non-void in a function. By appending dummy
+    // returns (that are unreachable) we can silence this compile error.
+    if (mFunctionType && mFunctionType->getBasicType() != EbtVoid)
+    {
+        TString typeString = mFunctionType->getStruct() ? mFunctionType->getStruct()->name() :
+            mFunctionType->getBasicString();
+        TString rawText = "return (" + typeString + ")0";
+        negatedElse = new TIntermRaw(*mFunctionType, rawText);
+    }
+
+    TIntermSelection *falseBlock = new TIntermSelection(negatedCondition,
+                                                        selection->getFalseBlock(), negatedElse);
+    TIntermSelection *newIfElse = new TIntermSelection(conditionSymbolC,
+                                                       selection->getTrueBlock(), falseBlock);
+
+    TIntermAggregate *declaration = new TIntermAggregate(EOpDeclaration);
+    declaration->getSequence().push_back(storeCondition);
+
+    TIntermAggregate *block = new TIntermAggregate(EOpSequence);
+    block->getSequence().push_back(declaration);
+    block->getSequence().push_back(newIfElse);
+
+    return block;
+}
+
+void RewriteElseBlocks(TIntermNode *node)
+{
+    ElseBlockRewriter rewriter;
+    node->traverse(&rewriter);
+}
+
+}