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

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• Hash : 4622905b
  Author :
  Date : 2018-12-10T13:31:00
  

  ES31: Add atomic memory functions for SSBO
  
  Due to SSBO is translated to RWByteAddressBuffer in HLSL, the corresponding
  atomic memory functions atomic* will be translated to
  RWByteAddressBuffer.Interlocked*. The translation is like below:
  
  atomicAdd(instanceName.data[0], 5u);
  // becomes
  uint _ssbo_atomicAdd_uint(RWByteAddressBuffer buffer, uint loc, uint value)
  {
      uint original_value;
      buffer.InterlockedAdd(loc, value, original_value);
      return original_value;
  }
  
  _ssbo_atomicAdd_uint(_instanceName, 0 + 16 * 0, 5);
  
  Bug: angleproject:1951
  
  Change-Id: If2af8bedb67a4135b443d2512d43c6058a78888d
  Reviewed-on: https://chromium-review.googlesource.com/c/1370676
  Reviewed-by: Corentin Wallez <cwallez@chromium.org>
  Commit-Queue: Jiajia Qin <jiajia.qin@intel.com>
  

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

• //
  // Copyright (c) 2018 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.
  //
  // Implementation of the function RewriteAtomicFunctionExpressions.
  // See the header for more details.
  
  #include "RewriteAtomicFunctionExpressions.h"
  
  #include "compiler/translator/tree_util/IntermNodePatternMatcher.h"
  #include "compiler/translator/tree_util/IntermNode_util.h"
  #include "compiler/translator/tree_util/IntermTraverse.h"
  #include "compiler/translator/util.h"
  
  namespace sh
  {
  namespace
  {
  // Traverser that simplifies all the atomic function expressions into the ones that can be directly
  // translated into HLSL.
  //
  // case 1 (only for atomicExchange and atomicCompSwap):
  //  original:
  //      atomicExchange(counter, newValue);
  //  new:
  //      tempValue = atomicExchange(counter, newValue);
  //
  // case 2 (atomic function, temporary variable required):
  //  original:
  //      value = atomicAdd(counter, 1) * otherValue;
  //      someArray[atomicAdd(counter, 1)] = someOtherValue;
  //  new:
  //      value = ((tempValue = atomicAdd(counter, 1)), tempValue) * otherValue;
  //      someArray[((tempValue = atomicAdd(counter, 1)), tempValue)] = someOtherValue;
  //
  // case 3 (atomic function used directly initialize a variable):
  //  original:
  //      int value = atomicAdd(counter, 1);
  //  new:
  //      tempValue = atomicAdd(counter, 1);
  //      int value = tempValue;
  //
  class RewriteAtomicFunctionExpressionsTraverser : public TIntermTraverser
  {
    public:
      RewriteAtomicFunctionExpressionsTraverser(TSymbolTable *symbolTable, int shaderVersion);
  
      bool visitAggregate(Visit visit, TIntermAggregate *node) override;
      bool visitBlock(Visit visit, TIntermBlock *node) override;
  
    private:
      static bool IsAtomicExchangeOrCompSwapNoReturnValue(TIntermAggregate *node,
                                                          TIntermNode *parentNode);
      static bool IsAtomicFunctionInsideExpression(TIntermAggregate *node, TIntermNode *parentNode);
  
      void rewriteAtomicFunctionCallNode(TIntermAggregate *oldAtomicFunctionNode);
  
      const TVariable *getTempVariable(const TType *type);
  
      int mShaderVersion;
      TIntermSequence mTempVariables;
  };
  
  RewriteAtomicFunctionExpressionsTraverser::RewriteAtomicFunctionExpressionsTraverser(
      TSymbolTable *symbolTable,
      int shaderVersion)
      : TIntermTraverser(false, false, true, symbolTable), mShaderVersion(shaderVersion)
  {}
  
  void RewriteAtomicFunctionExpressionsTraverser::rewriteAtomicFunctionCallNode(
      TIntermAggregate *oldAtomicFunctionNode)
  {
      ASSERT(oldAtomicFunctionNode);
  
      const TVariable *returnVariable = getTempVariable(&oldAtomicFunctionNode->getType());
  
      TIntermBinary *rewrittenNode = new TIntermBinary(
          TOperator::EOpAssign, CreateTempSymbolNode(returnVariable), oldAtomicFunctionNode);
  
      auto *parentNode = getParentNode();
  
      auto *parentBinary = parentNode->getAsBinaryNode();
      if (parentBinary && parentBinary->getOp() == EOpInitialize)
      {
          insertStatementInParentBlock(rewrittenNode);
          queueReplacement(CreateTempSymbolNode(returnVariable), OriginalNode::IS_DROPPED);
      }
      else
      {
          // As all atomic function assignment will be converted to the last argument of an
          // interlocked function, if we need the return value, assignment needs to be wrapped with
          // the comma operator and the temporary variables.
          if (!parentNode->getAsBlock())
          {
              rewrittenNode = TIntermBinary::CreateComma(
                  rewrittenNode, new TIntermSymbol(returnVariable), mShaderVersion);
          }
  
          queueReplacement(rewrittenNode, OriginalNode::IS_DROPPED);
      }
  }
  
  const TVariable *RewriteAtomicFunctionExpressionsTraverser::getTempVariable(const TType *type)
  {
      TIntermDeclaration *variableDeclaration;
      TVariable *returnVariable =
          DeclareTempVariable(mSymbolTable, type, EvqTemporary, &variableDeclaration);
      mTempVariables.push_back(variableDeclaration);
      return returnVariable;
  }
  
  bool RewriteAtomicFunctionExpressionsTraverser::IsAtomicExchangeOrCompSwapNoReturnValue(
      TIntermAggregate *node,
      TIntermNode *parentNode)
  {
      ASSERT(node);
      return (node->getOp() == EOpAtomicExchange || node->getOp() == EOpAtomicCompSwap) &&
             parentNode && parentNode->getAsBlock();
  }
  
  bool RewriteAtomicFunctionExpressionsTraverser::IsAtomicFunctionInsideExpression(
      TIntermAggregate *node,
      TIntermNode *parentNode)
  {
      ASSERT(node);
      // We only need to handle atomic functions with a parent that it is not block nodes. If the
      // parent node is block, it means that the atomic function is not inside an expression.
      if (!IsAtomicFunction(node->getOp()) || parentNode->getAsBlock())
      {
          return false;
      }
  
      auto *parentAsBinary = parentNode->getAsBinaryNode();
      // Assignments are handled in OutputHLSL
      return !parentAsBinary || parentAsBinary->getOp() != EOpAssign;
  }
  
  bool RewriteAtomicFunctionExpressionsTraverser::visitAggregate(Visit visit, TIntermAggregate *node)
  {
      ASSERT(visit == PostVisit);
      // Skip atomic memory functions for SSBO. They will be processed in the OutputHLSL traverser.
      if (IsAtomicFunction(node->getOp()) &&
          IsInShaderStorageBlock((*node->getSequence())[0]->getAsTyped()))
      {
          return false;
      }
  
      TIntermNode *parentNode = getParentNode();
      if (IsAtomicExchangeOrCompSwapNoReturnValue(node, parentNode) ||
          IsAtomicFunctionInsideExpression(node, parentNode))
      {
          rewriteAtomicFunctionCallNode(node);
      }
  
      return true;
  }
  
  bool RewriteAtomicFunctionExpressionsTraverser::visitBlock(Visit visit, TIntermBlock *node)
  {
      ASSERT(visit == PostVisit);
  
      if (!mTempVariables.empty() && getParentNode()->getAsFunctionDefinition())
      {
          insertStatementsInBlockAtPosition(node, 0, mTempVariables, TIntermSequence());
          mTempVariables.clear();
      }
  
      return true;
  }
  
  }  // anonymous namespace
  
  void RewriteAtomicFunctionExpressions(TIntermNode *root,
                                        TSymbolTable *symbolTable,
                                        int shaderVersion)
  {
      RewriteAtomicFunctionExpressionsTraverser traverser(symbolTable, shaderVersion);
      traverser.traverse(root);
      traverser.updateTree();
  }
  }  // namespace sh

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