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e25cd8860c
This change is needed for the next update to ToT LLVM. It can be put
into place now without breaking anything so I am committing it now.
The churn upstream on ilist_node is neccessary to remove undefined
behavior. Rather than updating the different ilist_node patches for the
hacky change required to not use iterators, just use iterators and keep
everything as ilist_nodes. Upstream they want to eventually do this, so
it makes sense for us to just do it now.
Please do not introduce new invocations of
ilist_node::get{Next,Prev}Node() into the tree.
116 lines
3.4 KiB
C++
116 lines
3.4 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 - 2016 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 immediate-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 definition 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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auto aIter = a->getIterator();
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auto bIter = b->getIterator();
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auto fIter = aBlock->begin();
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while (bIter != fIter) {
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--bIter;
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if (aIter == bIter)
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return true;
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}
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return false;
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}
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void DominanceInfo::verify() const {
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// Recompute.
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auto *F = getRoot()->getParent();
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DominanceInfo OtherDT(F);
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// And compare.
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if (errorOccurredOnComparison(OtherDT)) {
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llvm::errs() << "DominatorTree is not up to date!\nComputed:\n";
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print(llvm::errs());
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llvm::errs() << "\nActual:\n";
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OtherDT.print(llvm::errs());
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abort();
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}
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}
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/// Compute the immediate-post-dominators map.
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PostDominanceInfo::PostDominanceInfo(SILFunction *F)
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: DominatorTreeBase(/*isPostDom*/ true) {
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assert(!F->isExternalDeclaration() &&
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"Cannot construct a post dominator tree for a declaration");
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recalculate(*F);
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}
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bool
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PostDominanceInfo::
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properlyDominates(SILInstruction *I1, SILInstruction *I2) {
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SILBasicBlock *BB1 = I1->getParent(), *BB2 = I2->getParent();
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// If the blocks are different, it's as easy as whether BB1 post dominates
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// BB2.
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if (BB1 != BB2)
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return properlyDominates(BB1, BB2);
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// Otherwise, they're in the same block, and we just need to check
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// whether A comes after B.
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for (auto II = I1->getIterator(), IE = BB1->end(); II != IE; ++II) {
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if (&*II == I2) {
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return false;
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}
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}
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return true;
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}
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void PostDominanceInfo::verify() const {
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// Recompute.
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//
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// Even though at the SIL level we have "one" return function, we can have
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// multiple exits provided by no-return functions.
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auto *F = getRoots()[0]->getParent();
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PostDominanceInfo OtherDT(F);
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// And compare.
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if (errorOccurredOnComparison(OtherDT)) {
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llvm::errs() << "PostDominatorTree is not up to date!\nComputed:\n";
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print(llvm::errs());
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llvm::errs() << "\nActual:\n";
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OtherDT.print(llvm::errs());
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abort();
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}
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}
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