#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/IR/Dominators.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/InstVisitor.h"
#include "llvm/Support/SpecialCaseList.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Local.h"
+#include <algorithm>
#include <iterator>
+#include <set>
+#include <utility>
using namespace llvm;
std::unique_ptr<SpecialCaseList> SCL;
public:
- DFSanABIList(SpecialCaseList *SCL) : SCL(SCL) {}
+ DFSanABIList(std::unique_ptr<SpecialCaseList> SCL) : SCL(std::move(SCL)) {}
/// Returns whether either this function or its source file are listed in the
/// given category.
- bool isIn(const Function &F, const StringRef Category) const {
+ bool isIn(const Function &F, StringRef Category) const {
return isIn(*F.getParent(), Category) ||
SCL->inSection("fun", F.getName(), Category);
}
///
/// If GA aliases a function, the alias's name is matched as a function name
/// would be. Similarly, aliases of globals are matched like globals.
- bool isIn(const GlobalAlias &GA, const StringRef Category) const {
+ bool isIn(const GlobalAlias &GA, StringRef Category) const {
if (isIn(*GA.getParent(), Category))
return true;
}
/// Returns whether this module is listed in the given category.
- bool isIn(const Module &M, const StringRef Category) const {
+ bool isIn(const Module &M, StringRef Category) const {
return SCL->inSection("src", M.getModuleIdentifier(), Category);
}
};
FunctionType *DFSanSetLabelFnTy;
FunctionType *DFSanNonzeroLabelFnTy;
Constant *DFSanUnionFn;
+ Constant *DFSanCheckedUnionFn;
Constant *DFSanUnionLoadFn;
Constant *DFSanUnimplementedFn;
Constant *DFSanSetLabelFn;
struct DFSanFunction {
DataFlowSanitizer &DFS;
Function *F;
+ DominatorTree DT;
DataFlowSanitizer::InstrumentedABI IA;
bool IsNativeABI;
Value *ArgTLSPtr;
DenseMap<AllocaInst *, AllocaInst *> AllocaShadowMap;
std::vector<std::pair<PHINode *, PHINode *> > PHIFixups;
DenseSet<Instruction *> SkipInsts;
- DenseSet<Value *> NonZeroChecks;
+ std::vector<Value *> NonZeroChecks;
+ bool AvoidNewBlocks;
+
+ struct CachedCombinedShadow {
+ BasicBlock *Block;
+ Value *Shadow;
+ };
+ DenseMap<std::pair<Value *, Value *>, CachedCombinedShadow>
+ CachedCombinedShadows;
+ DenseMap<Value *, std::set<Value *>> ShadowElements;
DFSanFunction(DataFlowSanitizer &DFS, Function *F, bool IsNativeABI)
: DFS(DFS), F(F), IA(DFS.getInstrumentedABI()),
IsNativeABI(IsNativeABI), ArgTLSPtr(nullptr), RetvalTLSPtr(nullptr),
- LabelReturnAlloca(nullptr) {}
+ LabelReturnAlloca(nullptr) {
+ DT.recalculate(*F);
+ // FIXME: Need to track down the register allocator issue which causes poor
+ // performance in pathological cases with large numbers of basic blocks.
+ AvoidNewBlocks = F->size() > 1000;
+ }
Value *getArgTLSPtr();
Value *getArgTLS(unsigned Index, Instruction *Pos);
Value *getRetvalTLS();
DFSanSetLabelFnTy = FunctionType::get(Type::getVoidTy(*Ctx),
DFSanSetLabelArgs, /*isVarArg=*/false);
DFSanNonzeroLabelFnTy = FunctionType::get(
- Type::getVoidTy(*Ctx), ArrayRef<Type *>(), /*isVarArg=*/false);
+ Type::getVoidTy(*Ctx), None, /*isVarArg=*/false);
if (GetArgTLSPtr) {
Type *ArgTLSTy = ArrayType::get(ShadowTy, 64);
return WK_Functional;
if (ABIList.isIn(*F, "discard"))
return WK_Discard;
- if (ABIList.isIn(*F, "custom"))
+ if (ABIList.isIn(*F, "custom") && !F->isVarArg())
return WK_Custom;
return WK_Warning;
DFSanUnionFn = Mod->getOrInsertFunction("__dfsan_union", DFSanUnionFnTy);
if (Function *F = dyn_cast<Function>(DFSanUnionFn)) {
+ F->addAttribute(AttributeSet::FunctionIndex, Attribute::NoUnwind);
+ F->addAttribute(AttributeSet::FunctionIndex, Attribute::ReadNone);
+ F->addAttribute(AttributeSet::ReturnIndex, Attribute::ZExt);
+ F->addAttribute(1, Attribute::ZExt);
+ F->addAttribute(2, Attribute::ZExt);
+ }
+ DFSanCheckedUnionFn = Mod->getOrInsertFunction("dfsan_union", DFSanUnionFnTy);
+ if (Function *F = dyn_cast<Function>(DFSanCheckedUnionFn)) {
+ F->addAttribute(AttributeSet::FunctionIndex, Attribute::NoUnwind);
F->addAttribute(AttributeSet::FunctionIndex, Attribute::ReadNone);
F->addAttribute(AttributeSet::ReturnIndex, Attribute::ZExt);
F->addAttribute(1, Attribute::ZExt);
DFSanUnionLoadFn =
Mod->getOrInsertFunction("__dfsan_union_load", DFSanUnionLoadFnTy);
if (Function *F = dyn_cast<Function>(DFSanUnionLoadFn)) {
+ F->addAttribute(AttributeSet::FunctionIndex, Attribute::NoUnwind);
F->addAttribute(AttributeSet::FunctionIndex, Attribute::ReadOnly);
F->addAttribute(AttributeSet::ReturnIndex, Attribute::ZExt);
}
for (Module::iterator i = M.begin(), e = M.end(); i != e; ++i) {
if (!i->isIntrinsic() &&
i != DFSanUnionFn &&
+ i != DFSanCheckedUnionFn &&
i != DFSanUnionLoadFn &&
i != DFSanUnimplementedFn &&
i != DFSanSetLabelFn &&
// yet). To make our life easier, do this work in a pass after the main
// instrumentation.
if (ClDebugNonzeroLabels) {
- for (DenseSet<Value *>::iterator i = DFSF.NonZeroChecks.begin(),
- e = DFSF.NonZeroChecks.end();
- i != e; ++i) {
+ for (Value *V : DFSF.NonZeroChecks) {
Instruction *Pos;
- if (Instruction *I = dyn_cast<Instruction>(*i))
+ if (Instruction *I = dyn_cast<Instruction>(V))
Pos = I->getNextNode();
else
Pos = DFSF.F->getEntryBlock().begin();
while (isa<PHINode>(Pos) || isa<AllocaInst>(Pos))
Pos = Pos->getNextNode();
IRBuilder<> IRB(Pos);
- Value *Ne = IRB.CreateICmpNE(*i, DFSF.DFS.ZeroShadow);
+ Value *Ne = IRB.CreateICmpNE(V, DFSF.DFS.ZeroShadow);
BranchInst *BI = cast<BranchInst>(SplitBlockAndInsertIfThen(
Ne, Pos, /*Unreachable=*/false, ColdCallWeights));
IRBuilder<> ThenIRB(BI);
break;
}
}
- NonZeroChecks.insert(Shadow);
+ NonZeroChecks.push_back(Shadow);
} else {
Shadow = DFS.ZeroShadow;
}
return V1;
if (V1 == V2)
return V1;
+
+ auto V1Elems = ShadowElements.find(V1);
+ auto V2Elems = ShadowElements.find(V2);
+ if (V1Elems != ShadowElements.end() && V2Elems != ShadowElements.end()) {
+ if (std::includes(V1Elems->second.begin(), V1Elems->second.end(),
+ V2Elems->second.begin(), V2Elems->second.end())) {
+ return V1;
+ } else if (std::includes(V2Elems->second.begin(), V2Elems->second.end(),
+ V1Elems->second.begin(), V1Elems->second.end())) {
+ return V2;
+ }
+ } else if (V1Elems != ShadowElements.end()) {
+ if (V1Elems->second.count(V2))
+ return V1;
+ } else if (V2Elems != ShadowElements.end()) {
+ if (V2Elems->second.count(V1))
+ return V2;
+ }
+
+ auto Key = std::make_pair(V1, V2);
+ if (V1 > V2)
+ std::swap(Key.first, Key.second);
+ CachedCombinedShadow &CCS = CachedCombinedShadows[Key];
+ if (CCS.Block && DT.dominates(CCS.Block, Pos->getParent()))
+ return CCS.Shadow;
+
IRBuilder<> IRB(Pos);
- BasicBlock *Head = Pos->getParent();
- Value *Ne = IRB.CreateICmpNE(V1, V2);
- BranchInst *BI = cast<BranchInst>(SplitBlockAndInsertIfThen(
- Ne, Pos, /*Unreachable=*/false, DFS.ColdCallWeights, &DT));
- IRBuilder<> ThenIRB(BI);
- CallInst *Call = ThenIRB.CreateCall2(DFS.DFSanUnionFn, V1, V2);
- Call->addAttribute(AttributeSet::ReturnIndex, Attribute::ZExt);
- Call->addAttribute(1, Attribute::ZExt);
- Call->addAttribute(2, Attribute::ZExt);
-
- BasicBlock *Tail = BI->getSuccessor(0);
- PHINode *Phi = PHINode::Create(DFS.ShadowTy, 2, "", Tail->begin());
- Phi->addIncoming(Call, Call->getParent());
- Phi->addIncoming(V1, Head);
- return Phi;
+ if (AvoidNewBlocks) {
+ CallInst *Call = IRB.CreateCall2(DFS.DFSanCheckedUnionFn, V1, V2);
+ Call->addAttribute(AttributeSet::ReturnIndex, Attribute::ZExt);
+ Call->addAttribute(1, Attribute::ZExt);
+ Call->addAttribute(2, Attribute::ZExt);
+
+ CCS.Block = Pos->getParent();
+ CCS.Shadow = Call;
+ } else {
+ BasicBlock *Head = Pos->getParent();
+ Value *Ne = IRB.CreateICmpNE(V1, V2);
+ BranchInst *BI = cast<BranchInst>(SplitBlockAndInsertIfThen(
+ Ne, Pos, /*Unreachable=*/false, DFS.ColdCallWeights, &DT));
+ IRBuilder<> ThenIRB(BI);
+ CallInst *Call = ThenIRB.CreateCall2(DFS.DFSanUnionFn, V1, V2);
+ Call->addAttribute(AttributeSet::ReturnIndex, Attribute::ZExt);
+ Call->addAttribute(1, Attribute::ZExt);
+ Call->addAttribute(2, Attribute::ZExt);
+
+ BasicBlock *Tail = BI->getSuccessor(0);
+ PHINode *Phi = PHINode::Create(DFS.ShadowTy, 2, "", Tail->begin());
+ Phi->addIncoming(Call, Call->getParent());
+ Phi->addIncoming(V1, Head);
+
+ CCS.Block = Tail;
+ CCS.Shadow = Phi;
+ }
+
+ std::set<Value *> UnionElems;
+ if (V1Elems != ShadowElements.end()) {
+ UnionElems = V1Elems->second;
+ } else {
+ UnionElems.insert(V1);
+ }
+ if (V2Elems != ShadowElements.end()) {
+ UnionElems.insert(V2Elems->second.begin(), V2Elems->second.end());
+ } else {
+ UnionElems.insert(V2);
+ }
+ ShadowElements[CCS.Shadow] = std::move(UnionElems);
+
+ return CCS.Shadow;
}
// A convenience function which folds the shadows of each of the operands
IRB.CreateAlignedLoad(ShadowAddr1, ShadowAlign), Pos);
}
}
- if (Size % (64 / DFS.ShadowWidth) == 0) {
+ if (!AvoidNewBlocks && Size % (64 / DFS.ShadowWidth) == 0) {
// Fast path for the common case where each byte has identical shadow: load
// shadow 64 bits at a time, fall out to a __dfsan_union_load call if any
// shadow is non-equal.
BasicBlock *Head = Pos->getParent();
BasicBlock *Tail = Head->splitBasicBlock(Pos);
+
+ if (DomTreeNode *OldNode = DT.getNode(Head)) {
+ std::vector<DomTreeNode *> Children(OldNode->begin(), OldNode->end());
+
+ DomTreeNode *NewNode = DT.addNewBlock(Tail, Head);
+ for (auto Child : Children)
+ DT.changeImmediateDominator(Child, NewNode);
+ }
+
// In the following code LastBr will refer to the previous basic block's
// conditional branch instruction, whose true successor is fixed up to point
// to the next block during the loop below or to the tail after the final
// iteration.
BranchInst *LastBr = BranchInst::Create(FallbackBB, FallbackBB, ShadowsEq);
ReplaceInstWithInst(Head->getTerminator(), LastBr);
+ DT.addNewBlock(FallbackBB, Head);
for (uint64_t Ofs = 64 / DFS.ShadowWidth; Ofs != Size;
Ofs += 64 / DFS.ShadowWidth) {
BasicBlock *NextBB = BasicBlock::Create(*DFS.Ctx, "", F);
+ DT.addNewBlock(NextBB, LastBr->getParent());
IRBuilder<> NextIRB(NextBB);
WideAddr = NextIRB.CreateGEP(WideAddr, ConstantInt::get(DFS.IntptrTy, 1));
Value *NextWideShadow = NextIRB.CreateAlignedLoad(WideAddr, ShadowAlign);
void DFSanVisitor::visitLoadInst(LoadInst &LI) {
uint64_t Size = DFSF.DFS.DL->getTypeStoreSize(LI.getType());
+ if (Size == 0) {
+ DFSF.setShadow(&LI, DFSF.DFS.ZeroShadow);
+ return;
+ }
+
uint64_t Align;
if (ClPreserveAlignment) {
Align = LI.getAlignment();
Shadow = DFSF.combineShadows(Shadow, PtrShadow, &LI);
}
if (Shadow != DFSF.DFS.ZeroShadow)
- DFSF.NonZeroChecks.insert(Shadow);
+ DFSF.NonZeroChecks.push_back(Shadow);
DFSF.setShadow(&LI, Shadow);
}
void DFSanVisitor::visitStoreInst(StoreInst &SI) {
uint64_t Size =
DFSF.DFS.DL->getTypeStoreSize(SI.getValueOperand()->getType());
+ if (Size == 0)
+ return;
+
uint64_t Align;
if (ClPreserveAlignment) {
Align = SI.getAlignment();
LoadInst *LI = NextIRB.CreateLoad(DFSF.getRetvalTLS());
DFSF.SkipInsts.insert(LI);
DFSF.setShadow(CS.getInstruction(), LI);
- DFSF.NonZeroChecks.insert(LI);
+ DFSF.NonZeroChecks.push_back(LI);
}
}
ExtractValueInst::Create(NewCS.getInstruction(), 1, "", Next);
DFSF.SkipInsts.insert(ExShadow);
DFSF.setShadow(ExVal, ExShadow);
- DFSF.NonZeroChecks.insert(ExShadow);
+ DFSF.NonZeroChecks.push_back(ExShadow);
CS.getInstruction()->replaceAllUsesWith(ExVal);
}
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