kc3-lang/angle/src/compiler/translator/tree_ops/WrapSwitchStatementsInBlocks.cpp

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• Hash : 472c74c6
  Author :
  Date : 2019-08-19T16:32:13
  

  Translator: Allow tree validation in children of TCompiler
  
  This is to be able to perform validation inside TranslatorVulkan, even
  if it's through ASSERTs.
  
  Additionally, every transformation is changed such that they do their
  validation themselves.  TIntermTraverser::updateTree() performs the
  validation, which indirectly validates many of three tree
  transformations.  Some of the more ancient transformations that don't
  use this function directly call TCompiler::validateAST.
  
  Bug: angleproject:2733
  Change-Id: Ie4af029d34e053c5ad1dc8c2c2568eecd625d344
  Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1761149
  Reviewed-by: Geoff Lang <geofflang@chromium.org>
  Reviewed-by: Jamie Madill <jmadill@chromium.org>
  Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
  

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• src/compiler/translator/tree_ops/WrapSwitchStatementsInBlocks.cpp

• //
  // Copyright 2017 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.
  //
  // WrapSwitchStatementsInBlocks.cpp: Wrap switch statements in blocks and declare all switch-scoped
  // variables there to make the AST compatible with HLSL output.
  //
  // switch (init)
  // {
  //     case 0:
  //         float f;
  //     default:
  //         f = 1.0;
  // }
  //
  // becomes
  //
  // {
  //     float f;
  //     switch (init)
  //     {
  //         case 0:
  //         default:
  //             f = 1.0;
  //     }
  // }
  
  #include "compiler/translator/tree_ops/WrapSwitchStatementsInBlocks.h"
  
  #include "compiler/translator/IntermNode.h"
  #include "compiler/translator/tree_util/IntermTraverse.h"
  
  namespace sh
  {
  
  namespace
  {
  
  class WrapSwitchStatementsInBlocksTraverser : public TIntermTraverser
  {
    public:
      WrapSwitchStatementsInBlocksTraverser() : TIntermTraverser(true, false, false) {}
  
      bool visitSwitch(Visit visit, TIntermSwitch *node) override;
  };
  
  bool WrapSwitchStatementsInBlocksTraverser::visitSwitch(Visit, TIntermSwitch *node)
  {
      std::vector<TIntermDeclaration *> declarations;
      TIntermSequence *statementList = node->getStatementList()->getSequence();
      for (TIntermNode *statement : *statementList)
      {
          TIntermDeclaration *asDeclaration = statement->getAsDeclarationNode();
          if (asDeclaration)
          {
              declarations.push_back(asDeclaration);
          }
      }
      if (declarations.empty())
      {
          // We don't need to wrap the switch if it doesn't contain declarations as its direct
          // descendants.
          return true;
      }
  
      TIntermBlock *wrapperBlock = new TIntermBlock();
      for (TIntermDeclaration *declaration : declarations)
      {
          // SeparateDeclarations should have already been run.
          ASSERT(declaration->getSequence()->size() == 1);
  
          TIntermDeclaration *declarationInBlock = new TIntermDeclaration();
          TIntermSymbol *declaratorAsSymbol = declaration->getSequence()->at(0)->getAsSymbolNode();
          if (declaratorAsSymbol)
          {
              // This is a simple declaration like: "float f;"
              // Remove the declaration from inside the switch and put it in the wrapping block.
              TIntermSequence emptyReplacement;
              mMultiReplacements.push_back(NodeReplaceWithMultipleEntry(
                  node->getStatementList(), declaration, emptyReplacement));
  
              declarationInBlock->appendDeclarator(declaratorAsSymbol->deepCopy());
              // The declaration can't be the last statement inside the switch since unused variables
              // should already have been pruned.
              ASSERT(declaration != statementList->back());
          }
          else
          {
              // This is an init declaration like: "float f = 0.0;"
              // Change the init declaration inside the switch into an assignment and put a plain
              // declaration in the wrapping block.
              TIntermBinary *declaratorAsBinary =
                  declaration->getSequence()->at(0)->getAsBinaryNode();
              ASSERT(declaratorAsBinary);
  
              TIntermBinary *initAssignment = new TIntermBinary(
                  EOpAssign, declaratorAsBinary->getLeft(), declaratorAsBinary->getRight());
  
              queueReplacementWithParent(node->getStatementList(), declaration, initAssignment,
                                         OriginalNode::IS_DROPPED);
  
              declarationInBlock->appendDeclarator(declaratorAsBinary->getLeft()->deepCopy());
          }
          wrapperBlock->appendStatement(declarationInBlock);
      }
  
      wrapperBlock->appendStatement(node);
      queueReplacement(wrapperBlock, OriginalNode::BECOMES_CHILD);
  
      // Should be fine to process multiple switch statements, even nesting ones in the same
      // traversal.
      return true;
  }
  
  }  // anonymous namespace
  
  // Wrap switch statements in the AST into blocks when needed.
  bool WrapSwitchStatementsInBlocks(TCompiler *compiler, TIntermBlock *root)
  {
      WrapSwitchStatementsInBlocksTraverser traverser;
      root->traverse(&traverser);
      return traverser.updateTree(compiler, root);
  }
  
  }  // namespace sh
  

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