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Aug 21, 2019
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[ownership] Refactor linear lifetime checker so that it doesnt requir… #26767

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112 changes: 84 additions & 28 deletions lib/SIL/LinearLifetimeChecker.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -42,8 +42,14 @@ namespace {
using BrPropUserAndBlockPair = std::pair<BranchPropagatedUser, SILBasicBlock *>;

struct State {
/// The value that we are checking.
SILValue value;
/// If we are checking for a specific value, this is that value. This is only
/// used for diagnostic purposes. The algorithm if this is set works on the
/// parent block of the value.
Optional<SILValue> value;

/// The block where the live range begins. If the field value is not None,
/// then this is value->getParentBlock();
SILBasicBlock *beginBlock;

/// The result error object that use to signal either that no errors were
/// found or if errors are found the specific type of error that was found.
Expand Down Expand Up @@ -75,8 +81,15 @@ struct State {
State(SILValue value, SmallPtrSetImpl<SILBasicBlock *> &visitedBlocks,
ErrorBehaviorKind errorBehavior,
SmallVectorImpl<SILBasicBlock *> *leakingBlocks)
: value(value), error(errorBehavior), visitedBlocks(visitedBlocks),
leakingBlocks(leakingBlocks) {}
: value(value), beginBlock(value->getParentBlock()), error(errorBehavior),
visitedBlocks(visitedBlocks), leakingBlocks(leakingBlocks) {}

State(SILBasicBlock *beginBlock,
SmallPtrSetImpl<SILBasicBlock *> &visitedBlocks,
ErrorBehaviorKind errorBehavior,
SmallVectorImpl<SILBasicBlock *> *leakingBlocks)
: value(), beginBlock(beginBlock), error(errorBehavior),
visitedBlocks(visitedBlocks), leakingBlocks(leakingBlocks) {}

void initializeAllNonConsumingUses(
ArrayRef<BranchPropagatedUser> nonConsumingUsers);
Expand Down Expand Up @@ -183,7 +196,7 @@ void State::initializeAllConsumingUses(
// If this user is in the same block as the value, do not visit
// predecessors. We must be extra tolerant here since we allow for
// unreachable code.
if (userBlock == value->getParentBlock())
if (userBlock == beginBlock)
continue;

// Then for each predecessor of this block...
Expand All @@ -203,10 +216,15 @@ void State::initializeConsumingUse(BranchPropagatedUser consumingUser,
return;

error.handleOverConsume([&] {
llvm::errs() << "Function: '" << value->getFunction()->getName() << "'\n"
<< "Found over consume?!\n"
<< "Value: " << *value << "User: " << *consumingUser
<< "Block: bb" << userBlock->getDebugID() << "\n\n";
llvm::errs() << "Function: '" << beginBlock->getParent()->getName() << "'\n"
<< "Found over consume?!\n";
if (auto v = value) {
llvm::errs() << "Value: " << *value;
} else {
llvm::errs() << "Value: N/A\n";
}
llvm::errs() << "User: " << *consumingUser << "Block: bb"
<< userBlock->getDebugID() << "\n\n";
});
}

Expand All @@ -228,10 +246,16 @@ void State::checkForSameBlockUseAfterFree(BranchPropagatedUser consumingUser,
// the cond branch user is in a previous block. So just bail early.
if (consumingUser.isCondBranchUser()) {
error.handleUseAfterFree([&]() {
llvm::errs() << "Function: '" << value->getFunction()->getName() << "'\n"
llvm::errs() << "Function: '" << beginBlock->getParent()->getName()
<< "'\n"
<< "Found use after free?!\n"
<< "Value: " << *value
<< "Consuming User: " << *consumingUser
<< "Value: ";
if (auto v = value) {
llvm::errs() << *v;
} else {
llvm::errs() << "N/A. \n";
}
llvm::errs() << "Consuming User: " << *consumingUser
<< "Non Consuming User: " << *iter->second << "Block: bb"
<< userBlock->getDebugID() << "\n\n";
});
Expand All @@ -255,10 +279,16 @@ void State::checkForSameBlockUseAfterFree(BranchPropagatedUser consumingUser,
return nonConsumingUser == &i;
}) != userBlock->end()) {
error.handleUseAfterFree([&] {
llvm::errs() << "Function: '" << value->getFunction()->getName() << "'\n"
llvm::errs() << "Function: '" << beginBlock->getParent()->getName()
<< "'\n"
<< "Found use after free?!\n"
<< "Value: " << *value
<< "Consuming User: " << *consumingUser
<< "Value: ";
if (auto v = value) {
llvm::errs() << *v;
} else {
llvm::errs() << "N/A. \n";
}
llvm::errs() << "Consuming User: " << *consumingUser
<< "Non Consuming User: " << *iter->second << "Block: bb"
<< userBlock->getDebugID() << "\n\n";
});
Expand Down Expand Up @@ -287,10 +317,17 @@ void State::checkPredsForDoubleConsume(BranchPropagatedUser consumingUser,
}

error.handleOverConsume([&] {
llvm::errs() << "Function: '" << value->getFunction()->getName() << "'\n"
llvm::errs() << "Function: '" << beginBlock->getParent()->getName() << "'\n"
<< "Found over consume?!\n"
<< "Value: " << *value << "User: " << *consumingUser
<< "Block: bb" << userBlock->getDebugID() << "\n\n";
<< "Value: ";
if (auto v = value) {
llvm::errs() << *v;
} else {
llvm::errs() << "N/A. \n";
}

llvm::errs() << "User: " << *consumingUser << "Block: bb"
<< userBlock->getDebugID() << "\n\n";
});
}

Expand All @@ -310,10 +347,16 @@ void State::checkPredsForDoubleConsume(SILBasicBlock *userBlock) {
}

error.handleOverConsume([&] {
llvm::errs() << "Function: '" << value->getFunction()->getName() << "'\n"
llvm::errs() << "Function: '" << beginBlock->getParent()->getName() << "'\n"
<< "Found over consume?!\n"
<< "Value: " << *value << "Block: bb"
<< userBlock->getDebugID() << "\n\n";
<< "Value: ";
if (auto v = value) {
llvm::errs() << *v;
} else {
llvm::errs() << "N/A. \n";
}

llvm::errs() << "Block: bb" << userBlock->getDebugID() << "\n\n";
});
}

Expand Down Expand Up @@ -370,7 +413,7 @@ void State::performDataflow(DeadEndBlocks &deBlocks) {
// further to do since we do not want to visit the predecessors of our
// dominating block. On the other hand, we do want to add its successors to
// the successorBlocksThatMustBeVisited set.
if (block == value->getParentBlock())
if (block == beginBlock)
continue;

// Then for each predecessor of this block:
Expand Down Expand Up @@ -405,11 +448,16 @@ void State::checkDataflowEndState(DeadEndBlocks &deBlocks) {

// If we are supposed to error on leaks, do so now.
error.handleLeak([&] {
llvm::errs() << "Function: '" << value->getFunction()->getName() << "'\n"
llvm::errs() << "Function: '" << beginBlock->getParent()->getName()
<< "'\n"
<< "Error! Found a leak due to a consuming post-dominance "
"failure!\n"
<< " Value: " << *value
<< " Post Dominating Failure Blocks:\n";
"failure!\n";
if (auto v = value) {
llvm::errs() << "Value: " << *value;
} else {
llvm::errs() << "Value: N/A\n";
}
llvm::errs() << " Post Dominating Failure Blocks:\n";
for (auto *succBlock : successorBlocksThatMustBeVisited) {
llvm::errs() << " bb" << succBlock->getDebugID();
}
Expand All @@ -434,10 +482,18 @@ void State::checkDataflowEndState(DeadEndBlocks &deBlocks) {
}

error.handleUseAfterFree([&] {
llvm::errs() << "Function: '" << value->getFunction()->getName() << "'\n"
llvm::errs() << "Function: '" << beginBlock->getParent()->getName()
<< "'\n"
<< "Found use after free due to unvisited non lifetime "
"ending uses?!\n"
<< "Value: " << *value << " Remaining Users:\n";
<< "Value: ";
if (auto v = value) {
llvm::errs() << *v;
} else {
llvm::errs() << "N/A. \n";
}

llvm::errs() << " Remaining Users:\n";
for (auto &pair : blocksWithNonConsumingUses) {
llvm::errs() << "User:" << *pair.second << "Block: bb"
<< pair.first->getDebugID() << "\n";
Expand Down