kc3-lang/angle/src/compiler/translator/tree_util/RunAtTheEndOfShader.cpp

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• Hash : f0286e63
  Author :
  Date : 2021-01-19T12:38:46
  

  Translator: Stop allocating TIntermSequence
  
  The functions that take a TIntermSequence always copy out / Swap the
  contents away.  This change makes all TIntermSequences live on the stack
  instead of being newed.
  
  Bug: angleproject:5535
  Change-Id: I942f1c5e57b00199d5308183f71bd9e18b0608bd
  Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2636679
  Reviewed-by: Jamie Madill <jmadill@chromium.org>
  Reviewed-by: Tim Van Patten <timvp@google.com>
  Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
  

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• src/compiler/translator/tree_util/RunAtTheEndOfShader.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.
  //
  // RunAtTheEndOfShader.cpp: Add code to be run at the end of the shader. In case main() contains a
  // return statement, this is done by replacing the main() function with another function that calls
  // the old main, like this:
  //
  // void main() { body }
  // =>
  // void main0() { body }
  // void main()
  // {
  //     main0();
  //     codeToRun
  // }
  //
  // This way the code will get run even if the return statement inside main is executed.
  //
  
  #include "compiler/translator/tree_util/RunAtTheEndOfShader.h"
  
  #include "compiler/translator/Compiler.h"
  #include "compiler/translator/IntermNode.h"
  #include "compiler/translator/StaticType.h"
  #include "compiler/translator/SymbolTable.h"
  #include "compiler/translator/tree_util/FindMain.h"
  #include "compiler/translator/tree_util/IntermNode_util.h"
  #include "compiler/translator/tree_util/IntermTraverse.h"
  
  namespace sh
  {
  
  namespace
  {
  
  constexpr const ImmutableString kMainString("main");
  
  class ContainsReturnTraverser : public TIntermTraverser
  {
    public:
      ContainsReturnTraverser() : TIntermTraverser(true, false, false), mContainsReturn(false) {}
  
      bool visitBranch(Visit visit, TIntermBranch *node) override
      {
          if (node->getFlowOp() == EOpReturn)
          {
              mContainsReturn = true;
          }
          return false;
      }
  
      bool containsReturn() { return mContainsReturn; }
  
    private:
      bool mContainsReturn;
  };
  
  bool ContainsReturn(TIntermNode *node)
  {
      ContainsReturnTraverser traverser;
      node->traverse(&traverser);
      return traverser.containsReturn();
  }
  
  void WrapMainAndAppend(TIntermBlock *root,
                         TIntermFunctionDefinition *main,
                         TIntermNode *codeToRun,
                         TSymbolTable *symbolTable)
  {
      // Replace main() with main0() with the same body.
      TFunction *oldMain =
          new TFunction(symbolTable, kEmptyImmutableString, SymbolType::AngleInternal,
                        StaticType::GetBasic<EbtVoid>(), false);
      TIntermFunctionDefinition *oldMainDefinition =
          CreateInternalFunctionDefinitionNode(*oldMain, main->getBody());
  
      bool replaced = root->replaceChildNode(main, oldMainDefinition);
      ASSERT(replaced);
  
      // void main()
      TFunction *newMain = new TFunction(symbolTable, kMainString, SymbolType::UserDefined,
                                         StaticType::GetBasic<EbtVoid>(), false);
      TIntermFunctionPrototype *newMainProto = new TIntermFunctionPrototype(newMain);
  
      // {
      //     main0();
      //     codeToRun
      // }
      TIntermBlock *newMainBody = new TIntermBlock();
      TIntermSequence emptySequence;
      TIntermAggregate *oldMainCall = TIntermAggregate::CreateFunctionCall(*oldMain, &emptySequence);
      newMainBody->appendStatement(oldMainCall);
      newMainBody->appendStatement(codeToRun);
  
      // Add the new main() to the root node.
      TIntermFunctionDefinition *newMainDefinition =
          new TIntermFunctionDefinition(newMainProto, newMainBody);
      root->appendStatement(newMainDefinition);
  }
  
  }  // anonymous namespace
  
  bool RunAtTheEndOfShader(TCompiler *compiler,
                           TIntermBlock *root,
                           TIntermNode *codeToRun,
                           TSymbolTable *symbolTable)
  {
      TIntermFunctionDefinition *main = FindMain(root);
      if (!ContainsReturn(main))
      {
          main->getBody()->appendStatement(codeToRun);
      }
      else
      {
          WrapMainAndAppend(root, main, codeToRun, symbolTable);
      }
  
      return compiler->validateAST(root);
  }
  
  }  // namespace sh
  

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