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57 lines
1.9 KiB
C++
57 lines
1.9 KiB
C++
//===--- Dominance.cpp - SIL basic block dominance analysis ---------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2015 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See http://swift.org/LICENSE.txt for license information
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// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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#include "swift/SIL/SILFunction.h"
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#include "swift/SIL/SILBasicBlock.h"
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#include "swift/SIL/Dominance.h"
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#include "llvm/Support/GenericDomTree.h"
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#include "llvm/Support/GenericDomTreeConstruction.h"
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using namespace swift;
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template class llvm::DominatorTreeBase<SILBasicBlock>;
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template class llvm::DominatorBase<SILBasicBlock>;
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template class llvm::DomTreeNodeBase<SILBasicBlock>;
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/// Compute the immmediate-dominators map.
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DominanceInfo::DominanceInfo(SILFunction *F)
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: DominatorTreeBase(/*isPostDom*/ false) {
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assert(!F->isExternalDeclaration() &&
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"Make sure the function is a definicion and not a declaration.");
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recalculate(*F);
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}
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bool DominanceInfo::properlyDominates(SILInstruction *a, SILInstruction *b) {
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auto aBlock = a->getParent(), bBlock = b->getParent();
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// If the blocks are different, it's as easy as whether A's block
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// dominates B's block.
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if (aBlock != bBlock)
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return properlyDominates(a->getParent(), b->getParent());
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// Otherwise, they're in the same block, and we just need to check
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// whether B comes after A. This is a non-strict computation.
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SILInstruction *f = aBlock->begin();
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while (b != f) {
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b = b->getPrevNode();
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if (a == b) return true;
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}
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return false;
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}
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/// Compute the immmediate-post-dominators map.
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PostDominanceInfo::PostDominanceInfo(SILFunction *F)
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: DominatorTreeBase(/*isPostDom*/ true) {
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recalculate(*F);
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}
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