Files
swift-mirror/lib/SIL/Utils/Dominance.cpp
Michael Gottesman e1a19e4173 [sil] Split library into subfolders, while still building as a single library still.
Specifically, I split it into 3 initial categories: IR, Utils, Verifier. I just
did this quickly, we can always split it more later if we want.

I followed the model that we use in SILOptimizer: ./lib/SIL/CMakeLists.txt vends
 a macro (sil_register_sources) to the sub-folders that register the sources of
 the subdirectory with a global state variable that ./lib/SIL/CMakeLists.txt
 defines. Then after including those subdirs, the parent cmake declares the SIL
 library. So the output is the same, but we have the flexibility of having
 subdirectories to categorize source files.
2020-03-30 11:01:00 -07:00

134 lines
4.0 KiB
C++

//===--- Dominance.cpp - SIL basic block dominance analysis ---------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
#include "swift/SIL/SILFunction.h"
#include "swift/SIL/SILBasicBlock.h"
#include "swift/SIL/SILArgument.h"
#include "swift/SIL/Dominance.h"
#include "llvm/Support/GenericDomTreeConstruction.h"
using namespace swift;
template class llvm::DominatorTreeBase<SILBasicBlock, false>;
template class llvm::DominatorTreeBase<SILBasicBlock, true>;
template class llvm::DomTreeNodeBase<SILBasicBlock>;
namespace llvm {
namespace DomTreeBuilder {
template void Calculate<SILDomTree>(SILDomTree &DT);
template void Calculate<SILPostDomTree>(SILPostDomTree &DT);
} // namespace DomTreeBuilder
} // namespace llvm
/// Compute the immediate-dominators map.
DominanceInfo::DominanceInfo(SILFunction *F)
: DominatorTreeBase() {
assert(!F->isExternalDeclaration() &&
"Make sure the function is a definition and not a declaration.");
recalculate(*F);
}
bool DominanceInfo::properlyDominates(SILInstruction *a, SILInstruction *b) {
auto aBlock = a->getParent(), bBlock = b->getParent();
// If the blocks are different, it's as easy as whether A's block
// dominates B's block.
if (aBlock != bBlock)
return properlyDominates(a->getParent(), b->getParent());
// Otherwise, they're in the same block, and we just need to check
// whether B comes after A. This is a non-strict computation.
auto aIter = a->getIterator();
auto bIter = b->getIterator();
auto fIter = aBlock->begin();
while (bIter != fIter) {
--bIter;
if (aIter == bIter)
return true;
}
return false;
}
/// Does value A properly dominate instruction B?
bool DominanceInfo::properlyDominates(SILValue a, SILInstruction *b) {
if (auto *Inst = a->getDefiningInstruction()) {
return properlyDominates(Inst, b);
}
if (auto *Arg = dyn_cast<SILArgument>(a)) {
return dominates(Arg->getParent(), b->getParent());
}
return false;
}
void DominanceInfo::verify() const {
// Recompute.
auto *F = getRoot()->getParent();
DominanceInfo OtherDT(F);
// And compare.
if (errorOccurredOnComparison(OtherDT)) {
llvm::errs() << "DominatorTree is not up to date!\nComputed:\n";
print(llvm::errs());
llvm::errs() << "\nActual:\n";
OtherDT.print(llvm::errs());
abort();
}
}
/// Compute the immediate-post-dominators map.
PostDominanceInfo::PostDominanceInfo(SILFunction *F)
: PostDominatorTreeBase() {
assert(!F->isExternalDeclaration() &&
"Cannot construct a post dominator tree for a declaration");
recalculate(*F);
}
bool
PostDominanceInfo::
properlyDominates(SILInstruction *I1, SILInstruction *I2) {
SILBasicBlock *BB1 = I1->getParent(), *BB2 = I2->getParent();
// If the blocks are different, it's as easy as whether BB1 post dominates
// BB2.
if (BB1 != BB2)
return properlyDominates(BB1, BB2);
// Otherwise, they're in the same block, and we just need to check
// whether A comes after B.
for (auto II = I1->getIterator(), IE = BB1->end(); II != IE; ++II) {
if (&*II == I2) {
return false;
}
}
return true;
}
void PostDominanceInfo::verify() const {
// Recompute.
//
// Even though at the SIL level we have "one" return function, we can have
// multiple exits provided by no-return functions.
auto *F = getRoots()[0]->getParent();
PostDominanceInfo OtherDT(F);
// And compare.
if (errorOccurredOnComparison(OtherDT)) {
llvm::errs() << "PostDominatorTree is not up to date!\nComputed:\n";
print(llvm::errs());
llvm::errs() << "\nActual:\n";
OtherDT.print(llvm::errs());
abort();
}
}