kc3-lang/angle/src/compiler/translator/DeferGlobalInitializers.cpp

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• Hash : fe48632f
  Author :
  Date : 2017-03-21T09:30:54
  

  Prefer identifying functions by using symbol ids
  
  The shader translator code is now structured in a way that ensures
  that all function definition, function prototype and function call
  nodes store the integer symbol id for the function. This is guaranteed
  regardless of whether the function node is added while parsing or as a
  result of an AST transformation. TIntermAggregate nodes, which include
  function calls and constructors can now only be created by calling one
  of the TIntermAggregate::Create*() functions to ensure they have all
  the necessary properties.
  
  This makes it possible to keep track of functions using integer ids
  instead of their mangled name strings when generating the call graph
  and when using TLValueTrackingTraverser.
  
  This commit includes a few other small cleanups to the CallDAG class
  as well.
  
  BUG=angleproject:1490
  TEST=angle_unittests, angle_end2end_tests
  
  Change-Id: Idd1013506cbe4c3380e20d90524a9cd09b890259
  Reviewed-on: https://chromium-review.googlesource.com/459603
  Reviewed-by: Corentin Wallez <cwallez@chromium.org>
  Reviewed-by: Geoff Lang <geofflang@chromium.org>
  Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
  

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• src/compiler/translator/DeferGlobalInitializers.cpp

• //
  // Copyright (c) 2016 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.
  //
  // DeferGlobalInitializers is an AST traverser that moves global initializers into a function, and
  // adds a function call to that function in the beginning of main().
  // This enables initialization of globals with uniforms or non-constant globals, as allowed by
  // the WebGL spec. Some initializers referencing non-constants may need to be unfolded into if
  // statements in HLSL - this kind of steps should be done after DeferGlobalInitializers is run.
  //
  
  #include "compiler/translator/DeferGlobalInitializers.h"
  
  #include "compiler/translator/IntermNode.h"
  #include "compiler/translator/SymbolTable.h"
  
  namespace sh
  {
  
  namespace
  {
  
  class DeferGlobalInitializersTraverser : public TIntermTraverser
  {
    public:
      DeferGlobalInitializersTraverser();
  
      bool visitBinary(Visit visit, TIntermBinary *node) override;
  
      void insertInitFunction(TIntermBlock *root);
  
    private:
      TIntermSequence mDeferredInitializers;
  };
  
  DeferGlobalInitializersTraverser::DeferGlobalInitializersTraverser()
      : TIntermTraverser(true, false, false)
  {
  }
  
  bool DeferGlobalInitializersTraverser::visitBinary(Visit visit, TIntermBinary *node)
  {
      if (node->getOp() == EOpInitialize)
      {
          TIntermSymbol *symbolNode = node->getLeft()->getAsSymbolNode();
          ASSERT(symbolNode);
          TIntermTyped *expression = node->getRight();
  
          if (mInGlobalScope && (expression->getQualifier() != EvqConst ||
                                 (expression->getAsConstantUnion() == nullptr &&
                                  !expression->isConstructorWithOnlyConstantUnionParameters())))
          {
              // For variables which are not constant, defer their real initialization until
              // after we initialize uniforms.
              // Deferral is done also in any cases where the variable has not been constant folded,
              // since otherwise there's a chance that HLSL output will generate extra statements
              // from the initializer expression.
              TIntermBinary *deferredInit =
                  new TIntermBinary(EOpAssign, symbolNode->deepCopy(), node->getRight());
              mDeferredInitializers.push_back(deferredInit);
  
              // Change const global to a regular global if its initialization is deferred.
              // This can happen if ANGLE has not been able to fold the constant expression used
              // as an initializer.
              ASSERT(symbolNode->getQualifier() == EvqConst ||
                     symbolNode->getQualifier() == EvqGlobal);
              if (symbolNode->getQualifier() == EvqConst)
              {
                  // All of the siblings in the same declaration need to have consistent qualifiers.
                  auto *siblings = getParentNode()->getAsDeclarationNode()->getSequence();
                  for (TIntermNode *siblingNode : *siblings)
                  {
                      TIntermBinary *siblingBinary = siblingNode->getAsBinaryNode();
                      if (siblingBinary)
                      {
                          ASSERT(siblingBinary->getOp() == EOpInitialize);
                          siblingBinary->getLeft()->getTypePointer()->setQualifier(EvqGlobal);
                      }
                      siblingNode->getAsTyped()->getTypePointer()->setQualifier(EvqGlobal);
                  }
                  // This node is one of the siblings.
                  ASSERT(symbolNode->getQualifier() == EvqGlobal);
              }
              // Remove the initializer from the global scope and just declare the global instead.
              queueReplacement(node, symbolNode, OriginalNode::IS_DROPPED);
          }
      }
      return false;
  }
  
  void DeferGlobalInitializersTraverser::insertInitFunction(TIntermBlock *root)
  {
      if (mDeferredInitializers.empty())
      {
          return;
      }
      TSymbolUniqueId initFunctionId;
  
      const char *functionName = "initializeDeferredGlobals";
  
      // Add function prototype to the beginning of the shader
      TIntermFunctionPrototype *functionPrototypeNode =
          CreateInternalFunctionPrototypeNode(TType(EbtVoid), functionName, initFunctionId);
      root->getSequence()->insert(root->getSequence()->begin(), functionPrototypeNode);
  
      // Add function definition to the end of the shader
      TIntermBlock *functionBodyNode = new TIntermBlock();
      TIntermSequence *functionBody  = functionBodyNode->getSequence();
      for (const auto &deferredInit : mDeferredInitializers)
      {
          functionBody->push_back(deferredInit);
      }
      TIntermFunctionDefinition *functionDefinition = CreateInternalFunctionDefinitionNode(
          TType(EbtVoid), functionName, functionBodyNode, initFunctionId);
      root->getSequence()->push_back(functionDefinition);
  
      // Insert call into main function
      for (TIntermNode *node : *root->getSequence())
      {
          TIntermFunctionDefinition *nodeFunction = node->getAsFunctionDefinition();
          if (nodeFunction != nullptr && nodeFunction->getFunctionSymbolInfo()->isMain())
          {
              TIntermAggregate *functionCallNode = CreateInternalFunctionCallNode(
                  TType(EbtVoid), functionName, initFunctionId, nullptr);
  
              TIntermBlock *mainBody = nodeFunction->getBody();
              ASSERT(mainBody != nullptr);
              mainBody->getSequence()->insert(mainBody->getSequence()->begin(), functionCallNode);
          }
      }
  }
  
  }  // namespace
  
  void DeferGlobalInitializers(TIntermBlock *root)
  {
      DeferGlobalInitializersTraverser traverser;
      root->traverse(&traverser);
  
      // Replace the initializers of the global variables.
      traverser.updateTree();
  
      // Add the function with initialization and the call to that.
      traverser.insertInitFunction(root);
  }
  
  }  // namespace sh
  

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