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Diffstat (limited to 'src/3rdparty/angle/src/compiler/translator/DeferGlobalInitializers.cpp')
-rw-r--r-- | src/3rdparty/angle/src/compiler/translator/DeferGlobalInitializers.cpp | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/src/3rdparty/angle/src/compiler/translator/DeferGlobalInitializers.cpp b/src/3rdparty/angle/src/compiler/translator/DeferGlobalInitializers.cpp new file mode 100644 index 0000000000..67d51ea87b --- /dev/null +++ b/src/3rdparty/angle/src/compiler/translator/DeferGlobalInitializers.cpp @@ -0,0 +1,147 @@ +// +// 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 separate +// function that is called 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. Note that it's important that the function definition +// is at the end of the shader, as some globals may be declared after main(). +// +// It can also initialize all uninitialized globals. +// + +#include "compiler/translator/DeferGlobalInitializers.h" + +#include "compiler/translator/FindMain.h" +#include "compiler/translator/InitializeVariables.h" +#include "compiler/translator/IntermNode.h" +#include "compiler/translator/IntermNode_util.h" +#include "compiler/translator/SymbolTable.h" + +namespace sh +{ + +namespace +{ + +void GetDeferredInitializers(TIntermDeclaration *declaration, + bool initializeUninitializedGlobals, + bool canUseLoopsToInitialize, + TIntermSequence *deferredInitializersOut, + TSymbolTable *symbolTable) +{ + // SeparateDeclarations should have already been run. + ASSERT(declaration->getSequence()->size() == 1); + + TIntermNode *declarator = declaration->getSequence()->back(); + TIntermBinary *init = declarator->getAsBinaryNode(); + if (init) + { + TIntermSymbol *symbolNode = init->getLeft()->getAsSymbolNode(); + ASSERT(symbolNode); + TIntermTyped *expression = init->getRight(); + + if ((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. + + // 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) + { + symbolNode->getTypePointer()->setQualifier(EvqGlobal); + } + + TIntermBinary *deferredInit = + new TIntermBinary(EOpAssign, symbolNode->deepCopy(), init->getRight()); + deferredInitializersOut->push_back(deferredInit); + + // Remove the initializer from the global scope and just declare the global instead. + declaration->replaceChildNode(init, symbolNode); + } + } + else if (initializeUninitializedGlobals) + { + TIntermSymbol *symbolNode = declarator->getAsSymbolNode(); + ASSERT(symbolNode); + + // Ignore ANGLE internal variables. + if (symbolNode->getName().isInternal()) + return; + + if (symbolNode->getQualifier() == EvqGlobal && symbolNode->getSymbol() != "") + { + TIntermSequence *initCode = + CreateInitCode(symbolNode, canUseLoopsToInitialize, symbolTable); + deferredInitializersOut->insert(deferredInitializersOut->end(), initCode->begin(), + initCode->end()); + } + } +} + +void InsertInitCallToMain(TIntermBlock *root, + TIntermSequence *deferredInitializers, + TSymbolTable *symbolTable) +{ + TIntermBlock *initGlobalsBlock = new TIntermBlock(); + initGlobalsBlock->getSequence()->swap(*deferredInitializers); + + TSymbolUniqueId initGlobalsFunctionId(symbolTable); + + const char *kInitGlobalsFunctionName = "initGlobals"; + + TIntermFunctionPrototype *initGlobalsFunctionPrototype = + CreateInternalFunctionPrototypeNode(TType(), kInitGlobalsFunctionName, initGlobalsFunctionId); + root->getSequence()->insert(root->getSequence()->begin(), initGlobalsFunctionPrototype); + TIntermFunctionDefinition *initGlobalsFunctionDefinition = CreateInternalFunctionDefinitionNode( + TType(), kInitGlobalsFunctionName, initGlobalsBlock, initGlobalsFunctionId); + root->appendStatement(initGlobalsFunctionDefinition); + + TIntermAggregate *initGlobalsCall = CreateInternalFunctionCallNode( + TType(), kInitGlobalsFunctionName, initGlobalsFunctionId, new TIntermSequence()); + + TIntermBlock *mainBody = FindMainBody(root); + mainBody->getSequence()->insert(mainBody->getSequence()->begin(), initGlobalsCall); +} + +} // namespace + +void DeferGlobalInitializers(TIntermBlock *root, + bool initializeUninitializedGlobals, + bool canUseLoopsToInitialize, + TSymbolTable *symbolTable) +{ + TIntermSequence *deferredInitializers = new TIntermSequence(); + + // Loop over all global statements and process the declarations. This is simpler than using a + // traverser. + for (TIntermNode *statement : *root->getSequence()) + { + TIntermDeclaration *declaration = statement->getAsDeclarationNode(); + if (declaration) + { + GetDeferredInitializers(declaration, initializeUninitializedGlobals, + canUseLoopsToInitialize, deferredInitializers, symbolTable); + } + } + + // Add the function with initialization and the call to that. + if (!deferredInitializers->empty()) + { + InsertInitCallToMain(root, deferredInitializers, symbolTable); + } +} + +} // namespace sh |