forked from OSchip/llvm-project
730 lines
24 KiB
C++
730 lines
24 KiB
C++
//===- StackSafetyAnalysis.cpp - Stack memory safety analysis -------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/StackSafetyAnalysis.h"
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#include "llvm/Analysis/ScalarEvolutionExpressions.h"
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#include "llvm/IR/InstIterator.h"
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#include "llvm/IR/IntrinsicInst.h"
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#include "llvm/InitializePasses.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/raw_ostream.h"
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using namespace llvm;
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#define DEBUG_TYPE "stack-safety"
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static cl::opt<int> StackSafetyMaxIterations("stack-safety-max-iterations",
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cl::init(20), cl::Hidden);
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namespace {
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/// Rewrite an SCEV expression for a memory access address to an expression that
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/// represents offset from the given alloca.
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class AllocaOffsetRewriter : public SCEVRewriteVisitor<AllocaOffsetRewriter> {
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const Value *AllocaPtr;
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public:
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AllocaOffsetRewriter(ScalarEvolution &SE, const Value *AllocaPtr)
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: SCEVRewriteVisitor(SE), AllocaPtr(AllocaPtr) {}
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const SCEV *visit(const SCEV *Expr) {
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// Only re-write the expression if the alloca is used in an addition
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// expression (it can be used in other types of expressions if it's cast to
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// an int and passed as an argument.)
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if (!isa<SCEVAddRecExpr>(Expr) && !isa<SCEVAddExpr>(Expr) &&
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!isa<SCEVUnknown>(Expr))
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return Expr;
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return SCEVRewriteVisitor<AllocaOffsetRewriter>::visit(Expr);
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}
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const SCEV *visitUnknown(const SCEVUnknown *Expr) {
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// FIXME: look through one or several levels of definitions?
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// This can be inttoptr(AllocaPtr) and SCEV would not unwrap
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// it for us.
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if (Expr->getValue() == AllocaPtr)
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return SE.getZero(Expr->getType());
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return Expr;
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}
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};
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/// Describes use of address in as a function call argument.
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struct PassAsArgInfo {
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/// Function being called.
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const GlobalValue *Callee = nullptr;
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/// Index of argument which pass address.
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size_t ParamNo = 0;
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// Offset range of address from base address (alloca or calling function
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// argument).
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// Range should never set to empty-set, that is an invalid access range
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// that can cause empty-set to be propagated with ConstantRange::add
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ConstantRange Offset;
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PassAsArgInfo(const GlobalValue *Callee, size_t ParamNo, ConstantRange Offset)
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: Callee(Callee), ParamNo(ParamNo), Offset(Offset) {}
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StringRef getName() const { return Callee->getName(); }
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};
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raw_ostream &operator<<(raw_ostream &OS, const PassAsArgInfo &P) {
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return OS << "@" << P.getName() << "(arg" << P.ParamNo << ", " << P.Offset
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<< ")";
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}
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/// Describe uses of address (alloca or parameter) inside of the function.
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struct UseInfo {
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// Access range if the address (alloca or parameters).
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// It is allowed to be empty-set when there are no known accesses.
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ConstantRange Range;
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// List of calls which pass address as an argument.
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SmallVector<PassAsArgInfo, 4> Calls;
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explicit UseInfo(unsigned PointerSize) : Range{PointerSize, false} {}
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void updateRange(ConstantRange R) { Range = Range.unionWith(R); }
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};
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raw_ostream &operator<<(raw_ostream &OS, const UseInfo &U) {
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OS << U.Range;
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for (auto &Call : U.Calls)
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OS << ", " << Call;
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return OS;
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}
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struct AllocaInfo {
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AllocaInst *AI = nullptr;
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uint64_t Size = 0;
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UseInfo Use;
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AllocaInfo(unsigned PointerSize, AllocaInst *AI, uint64_t Size)
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: AI(AI), Size(Size), Use(PointerSize) {}
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StringRef getName() const { return AI->getName(); }
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};
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raw_ostream &operator<<(raw_ostream &OS, const AllocaInfo &A) {
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return OS << A.getName() << "[" << A.Size << "]: " << A.Use;
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}
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struct ParamInfo {
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const Argument *Arg = nullptr;
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UseInfo Use;
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explicit ParamInfo(unsigned PointerSize, const Argument *Arg)
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: Arg(Arg), Use(PointerSize) {}
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StringRef getName() const { return Arg ? Arg->getName() : "<N/A>"; }
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};
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raw_ostream &operator<<(raw_ostream &OS, const ParamInfo &P) {
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return OS << P.getName() << "[]: " << P.Use;
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}
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/// Calculate the allocation size of a given alloca. Returns 0 if the
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/// size can not be statically determined.
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uint64_t getStaticAllocaAllocationSize(const AllocaInst *AI) {
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const DataLayout &DL = AI->getModule()->getDataLayout();
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TypeSize TS = DL.getTypeAllocSize(AI->getAllocatedType());
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if (TS.isScalable())
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return 0;
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uint64_t Size = TS.getFixedSize();
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if (AI->isArrayAllocation()) {
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auto C = dyn_cast<ConstantInt>(AI->getArraySize());
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if (!C)
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return 0;
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Size *= C->getZExtValue();
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}
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return Size;
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}
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} // end anonymous namespace
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/// Describes uses of allocas and parameters inside of a single function.
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struct StackSafetyInfo::FunctionInfo {
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// May be a Function or a GlobalAlias
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const GlobalValue *GV = nullptr;
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// Informations about allocas uses.
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SmallVector<AllocaInfo, 4> Allocas;
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// Informations about parameters uses.
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SmallVector<ParamInfo, 4> Params;
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// TODO: describe return value as depending on one or more of its arguments.
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// StackSafetyDataFlowAnalysis counter stored here for faster access.
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int UpdateCount = 0;
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FunctionInfo(const StackSafetyInfo &SSI) : FunctionInfo(*SSI.Info) {}
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explicit FunctionInfo(const Function *F) : GV(F){};
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// Creates FunctionInfo that forwards all the parameters to the aliasee.
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explicit FunctionInfo(const GlobalAlias *A);
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FunctionInfo(FunctionInfo &&) = default;
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bool IsDSOLocal() const { return GV->isDSOLocal(); };
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bool IsInterposable() const { return GV->isInterposable(); };
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StringRef getName() const { return GV->getName(); }
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void print(raw_ostream &O) const {
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// TODO: Consider different printout format after
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// StackSafetyDataFlowAnalysis. Calls and parameters are irrelevant then.
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O << " @" << getName() << (IsDSOLocal() ? "" : " dso_preemptable")
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<< (IsInterposable() ? " interposable" : "") << "\n";
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O << " args uses:\n";
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for (auto &P : Params)
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O << " " << P << "\n";
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O << " allocas uses:\n";
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for (auto &AS : Allocas)
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O << " " << AS << "\n";
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}
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private:
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FunctionInfo(const FunctionInfo &) = default;
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};
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StackSafetyInfo::FunctionInfo::FunctionInfo(const GlobalAlias *A) : GV(A) {
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unsigned PointerSize = A->getParent()->getDataLayout().getPointerSizeInBits();
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const GlobalObject *Aliasee = A->getBaseObject();
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const FunctionType *Type = cast<FunctionType>(Aliasee->getValueType());
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// 'Forward' all parameters to this alias to the aliasee
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for (unsigned ArgNo = 0; ArgNo < Type->getNumParams(); ArgNo++) {
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Params.emplace_back(PointerSize, nullptr);
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UseInfo &US = Params.back().Use;
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US.Calls.emplace_back(Aliasee, ArgNo, ConstantRange(APInt(PointerSize, 0)));
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}
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}
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namespace {
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class StackSafetyLocalAnalysis {
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Function &F;
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const DataLayout &DL;
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ScalarEvolution &SE;
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unsigned PointerSize = 0;
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const ConstantRange UnknownRange;
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ConstantRange offsetFromAlloca(Value *Addr, const Value *AllocaPtr);
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ConstantRange getAccessRange(Value *Addr, const Value *AllocaPtr,
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ConstantRange SizeRange);
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ConstantRange getAccessRange(Value *Addr, const Value *AllocaPtr,
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TypeSize Size);
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ConstantRange getMemIntrinsicAccessRange(const MemIntrinsic *MI, const Use &U,
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const Value *AllocaPtr);
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bool analyzeAllUses(const Value *Ptr, UseInfo &AS);
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ConstantRange getRange(uint64_t Lower, uint64_t Upper) const {
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return ConstantRange(APInt(PointerSize, Lower), APInt(PointerSize, Upper));
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}
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public:
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StackSafetyLocalAnalysis(Function &F, ScalarEvolution &SE)
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: F(F), DL(F.getParent()->getDataLayout()), SE(SE),
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PointerSize(DL.getPointerSizeInBits()),
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UnknownRange(PointerSize, true) {}
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// Run the transformation on the associated function.
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StackSafetyInfo run();
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};
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ConstantRange
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StackSafetyLocalAnalysis::offsetFromAlloca(Value *Addr,
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const Value *AllocaPtr) {
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if (!SE.isSCEVable(Addr->getType()))
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return UnknownRange;
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AllocaOffsetRewriter Rewriter(SE, AllocaPtr);
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const SCEV *Expr = Rewriter.visit(SE.getSCEV(Addr));
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ConstantRange Offset = SE.getUnsignedRange(Expr).zextOrTrunc(PointerSize);
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assert(!Offset.isEmptySet());
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return Offset;
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}
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ConstantRange
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StackSafetyLocalAnalysis::getAccessRange(Value *Addr, const Value *AllocaPtr,
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ConstantRange SizeRange) {
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// Zero-size loads and stores do not access memory.
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if (SizeRange.isEmptySet())
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return ConstantRange::getEmpty(PointerSize);
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if (!SE.isSCEVable(Addr->getType()))
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return UnknownRange;
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AllocaOffsetRewriter Rewriter(SE, AllocaPtr);
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const SCEV *Expr = Rewriter.visit(SE.getSCEV(Addr));
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ConstantRange AccessStartRange =
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SE.getUnsignedRange(Expr).zextOrTrunc(PointerSize);
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ConstantRange AccessRange = AccessStartRange.add(SizeRange);
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assert(!AccessRange.isEmptySet());
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return AccessRange;
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}
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ConstantRange StackSafetyLocalAnalysis::getAccessRange(Value *Addr,
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const Value *AllocaPtr,
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TypeSize Size) {
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ConstantRange SizeRange = Size.isScalable()
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? ConstantRange::getFull(PointerSize)
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: getRange(0, Size.getFixedSize());
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return getAccessRange(Addr, AllocaPtr, SizeRange);
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}
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ConstantRange StackSafetyLocalAnalysis::getMemIntrinsicAccessRange(
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const MemIntrinsic *MI, const Use &U, const Value *AllocaPtr) {
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if (auto MTI = dyn_cast<MemTransferInst>(MI)) {
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if (MTI->getRawSource() != U && MTI->getRawDest() != U)
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return getRange(0, 1);
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} else {
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if (MI->getRawDest() != U)
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return getRange(0, 1);
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}
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const auto *Len = dyn_cast<ConstantInt>(MI->getLength());
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// Non-constant size => unsafe. FIXME: try SCEV getRange.
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if (!Len)
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return UnknownRange;
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ConstantRange AccessRange =
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getAccessRange(U, AllocaPtr, getRange(0, Len->getZExtValue()));
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return AccessRange;
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}
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/// The function analyzes all local uses of Ptr (alloca or argument) and
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/// calculates local access range and all function calls where it was used.
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bool StackSafetyLocalAnalysis::analyzeAllUses(const Value *Ptr, UseInfo &US) {
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SmallPtrSet<const Value *, 16> Visited;
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SmallVector<const Value *, 8> WorkList;
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WorkList.push_back(Ptr);
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// A DFS search through all uses of the alloca in bitcasts/PHI/GEPs/etc.
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while (!WorkList.empty()) {
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const Value *V = WorkList.pop_back_val();
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for (const Use &UI : V->uses()) {
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auto I = cast<const Instruction>(UI.getUser());
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assert(V == UI.get());
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switch (I->getOpcode()) {
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case Instruction::Load: {
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US.updateRange(
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getAccessRange(UI, Ptr, DL.getTypeStoreSize(I->getType())));
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break;
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}
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case Instruction::VAArg:
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// "va-arg" from a pointer is safe.
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break;
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case Instruction::Store: {
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if (V == I->getOperand(0)) {
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// Stored the pointer - conservatively assume it may be unsafe.
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US.updateRange(UnknownRange);
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return false;
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}
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US.updateRange(getAccessRange(
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UI, Ptr, DL.getTypeStoreSize(I->getOperand(0)->getType())));
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break;
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}
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case Instruction::Ret:
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// Information leak.
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// FIXME: Process parameters correctly. This is a leak only if we return
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// alloca.
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US.updateRange(UnknownRange);
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return false;
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case Instruction::Call:
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case Instruction::Invoke: {
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const auto &CB = cast<CallBase>(*I);
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if (I->isLifetimeStartOrEnd())
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break;
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if (const MemIntrinsic *MI = dyn_cast<MemIntrinsic>(I)) {
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US.updateRange(getMemIntrinsicAccessRange(MI, UI, Ptr));
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break;
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}
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// FIXME: consult devirt?
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// Do not follow aliases, otherwise we could inadvertently follow
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// dso_preemptable aliases or aliases with interposable linkage.
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const GlobalValue *Callee =
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dyn_cast<GlobalValue>(CB.getCalledOperand()->stripPointerCasts());
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if (!Callee) {
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US.updateRange(UnknownRange);
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return false;
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}
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assert(isa<Function>(Callee) || isa<GlobalAlias>(Callee));
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auto B = CB.arg_begin(), E = CB.arg_end();
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for (auto A = B; A != E; ++A) {
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if (A->get() == V) {
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ConstantRange Offset = offsetFromAlloca(UI, Ptr);
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US.Calls.emplace_back(Callee, A - B, Offset);
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}
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}
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break;
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}
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default:
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if (Visited.insert(I).second)
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WorkList.push_back(cast<const Instruction>(I));
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}
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}
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}
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return true;
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}
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StackSafetyInfo StackSafetyLocalAnalysis::run() {
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StackSafetyInfo::FunctionInfo Info(&F);
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assert(!F.isDeclaration() &&
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"Can't run StackSafety on a function declaration");
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LLVM_DEBUG(dbgs() << "[StackSafety] " << F.getName() << "\n");
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for (auto &I : instructions(F)) {
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if (auto AI = dyn_cast<AllocaInst>(&I)) {
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Info.Allocas.emplace_back(PointerSize, AI,
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getStaticAllocaAllocationSize(AI));
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AllocaInfo &AS = Info.Allocas.back();
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analyzeAllUses(AI, AS.Use);
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}
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}
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for (const Argument &A : make_range(F.arg_begin(), F.arg_end())) {
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Info.Params.emplace_back(PointerSize, &A);
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ParamInfo &PS = Info.Params.back();
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analyzeAllUses(&A, PS.Use);
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}
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LLVM_DEBUG(dbgs() << "[StackSafety] done\n");
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LLVM_DEBUG(Info.print(dbgs()));
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return StackSafetyInfo(std::move(Info));
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}
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class StackSafetyDataFlowAnalysis {
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using FunctionMap =
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std::map<const GlobalValue *, StackSafetyInfo::FunctionInfo>;
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FunctionMap Functions;
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// Callee-to-Caller multimap.
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DenseMap<const GlobalValue *, SmallVector<const GlobalValue *, 4>> Callers;
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SetVector<const GlobalValue *> WorkList;
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unsigned PointerSize = 0;
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const ConstantRange UnknownRange;
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ConstantRange getArgumentAccessRange(const GlobalValue *Callee,
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unsigned ParamNo) const;
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bool updateOneUse(UseInfo &US, bool UpdateToFullSet);
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void updateOneNode(const GlobalValue *Callee,
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StackSafetyInfo::FunctionInfo &FS);
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void updateOneNode(const GlobalValue *Callee) {
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updateOneNode(Callee, Functions.find(Callee)->second);
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}
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void updateAllNodes() {
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for (auto &F : Functions)
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updateOneNode(F.first, F.second);
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}
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void runDataFlow();
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#ifndef NDEBUG
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void verifyFixedPoint();
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#endif
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public:
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StackSafetyDataFlowAnalysis(
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Module &M, std::function<const StackSafetyInfo &(Function &)> FI);
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StackSafetyGlobalInfo run();
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};
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StackSafetyDataFlowAnalysis::StackSafetyDataFlowAnalysis(
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Module &M, std::function<const StackSafetyInfo &(Function &)> FI)
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: PointerSize(M.getDataLayout().getPointerSizeInBits()),
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UnknownRange(PointerSize, true) {
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// Without ThinLTO, run the local analysis for every function in the TU and
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// then run the DFA.
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for (auto &F : M.functions())
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if (!F.isDeclaration())
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Functions.emplace(&F, FI(F));
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for (auto &A : M.aliases())
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if (isa<Function>(A.getBaseObject()))
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Functions.emplace(&A, StackSafetyInfo::FunctionInfo(&A));
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}
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ConstantRange
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StackSafetyDataFlowAnalysis::getArgumentAccessRange(const GlobalValue *Callee,
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unsigned ParamNo) const {
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auto IT = Functions.find(Callee);
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// Unknown callee (outside of LTO domain or an indirect call).
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if (IT == Functions.end())
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return UnknownRange;
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const StackSafetyInfo::FunctionInfo &FS = IT->second;
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// The definition of this symbol may not be the definition in this linkage
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// unit.
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if (!FS.IsDSOLocal() || FS.IsInterposable())
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return UnknownRange;
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if (ParamNo >= FS.Params.size()) // possibly vararg
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return UnknownRange;
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return FS.Params[ParamNo].Use.Range;
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}
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bool StackSafetyDataFlowAnalysis::updateOneUse(UseInfo &US,
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bool UpdateToFullSet) {
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bool Changed = false;
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for (auto &CS : US.Calls) {
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assert(!CS.Offset.isEmptySet() &&
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"Param range can't be empty-set, invalid offset range");
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ConstantRange CalleeRange = getArgumentAccessRange(CS.Callee, CS.ParamNo);
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CalleeRange = CalleeRange.add(CS.Offset);
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if (!US.Range.contains(CalleeRange)) {
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Changed = true;
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if (UpdateToFullSet)
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US.Range = UnknownRange;
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else
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US.Range = US.Range.unionWith(CalleeRange);
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}
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}
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return Changed;
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}
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void StackSafetyDataFlowAnalysis::updateOneNode(
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const GlobalValue *Callee, StackSafetyInfo::FunctionInfo &FS) {
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bool UpdateToFullSet = FS.UpdateCount > StackSafetyMaxIterations;
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bool Changed = false;
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for (auto &AS : FS.Allocas)
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Changed |= updateOneUse(AS.Use, UpdateToFullSet);
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|
for (auto &PS : FS.Params)
|
|
Changed |= updateOneUse(PS.Use, UpdateToFullSet);
|
|
|
|
if (Changed) {
|
|
LLVM_DEBUG(dbgs() << "=== update [" << FS.UpdateCount
|
|
<< (UpdateToFullSet ? ", full-set" : "") << "] "
|
|
<< FS.getName() << "\n");
|
|
// Callers of this function may need updating.
|
|
for (auto &CallerID : Callers[Callee])
|
|
WorkList.insert(CallerID);
|
|
|
|
++FS.UpdateCount;
|
|
}
|
|
}
|
|
|
|
void StackSafetyDataFlowAnalysis::runDataFlow() {
|
|
Callers.clear();
|
|
WorkList.clear();
|
|
|
|
SmallVector<const GlobalValue *, 16> Callees;
|
|
for (auto &F : Functions) {
|
|
Callees.clear();
|
|
StackSafetyInfo::FunctionInfo &FS = F.second;
|
|
for (auto &AS : FS.Allocas)
|
|
for (auto &CS : AS.Use.Calls)
|
|
Callees.push_back(CS.Callee);
|
|
for (auto &PS : FS.Params)
|
|
for (auto &CS : PS.Use.Calls)
|
|
Callees.push_back(CS.Callee);
|
|
|
|
llvm::sort(Callees);
|
|
Callees.erase(std::unique(Callees.begin(), Callees.end()), Callees.end());
|
|
|
|
for (auto &Callee : Callees)
|
|
Callers[Callee].push_back(F.first);
|
|
}
|
|
|
|
updateAllNodes();
|
|
|
|
while (!WorkList.empty()) {
|
|
const GlobalValue *Callee = WorkList.back();
|
|
WorkList.pop_back();
|
|
updateOneNode(Callee);
|
|
}
|
|
}
|
|
|
|
#ifndef NDEBUG
|
|
void StackSafetyDataFlowAnalysis::verifyFixedPoint() {
|
|
WorkList.clear();
|
|
updateAllNodes();
|
|
assert(WorkList.empty());
|
|
}
|
|
#endif
|
|
|
|
StackSafetyGlobalInfo StackSafetyDataFlowAnalysis::run() {
|
|
runDataFlow();
|
|
LLVM_DEBUG(verifyFixedPoint());
|
|
|
|
StackSafetyGlobalInfo SSI;
|
|
for (auto &F : Functions)
|
|
SSI.emplace(F.first, std::move(F.second));
|
|
return SSI;
|
|
}
|
|
|
|
void print(const StackSafetyGlobalInfo &SSI, raw_ostream &O, const Module &M) {
|
|
size_t Count = 0;
|
|
for (auto &F : M.functions())
|
|
if (!F.isDeclaration()) {
|
|
SSI.find(&F)->second.print(O);
|
|
O << "\n";
|
|
++Count;
|
|
}
|
|
for (auto &A : M.aliases()) {
|
|
SSI.find(&A)->second.print(O);
|
|
O << "\n";
|
|
++Count;
|
|
}
|
|
assert(Count == SSI.size() && "Unexpected functions in the result");
|
|
}
|
|
|
|
} // end anonymous namespace
|
|
|
|
StackSafetyInfo::StackSafetyInfo() = default;
|
|
StackSafetyInfo::StackSafetyInfo(StackSafetyInfo &&) = default;
|
|
StackSafetyInfo &StackSafetyInfo::operator=(StackSafetyInfo &&) = default;
|
|
|
|
StackSafetyInfo::StackSafetyInfo(FunctionInfo &&Info)
|
|
: Info(new FunctionInfo(std::move(Info))) {}
|
|
|
|
StackSafetyInfo::~StackSafetyInfo() = default;
|
|
|
|
void StackSafetyInfo::print(raw_ostream &O) const { Info->print(O); }
|
|
|
|
AnalysisKey StackSafetyAnalysis::Key;
|
|
|
|
StackSafetyInfo StackSafetyAnalysis::run(Function &F,
|
|
FunctionAnalysisManager &AM) {
|
|
StackSafetyLocalAnalysis SSLA(F, AM.getResult<ScalarEvolutionAnalysis>(F));
|
|
return SSLA.run();
|
|
}
|
|
|
|
PreservedAnalyses StackSafetyPrinterPass::run(Function &F,
|
|
FunctionAnalysisManager &AM) {
|
|
OS << "'Stack Safety Local Analysis' for function '" << F.getName() << "'\n";
|
|
AM.getResult<StackSafetyAnalysis>(F).print(OS);
|
|
return PreservedAnalyses::all();
|
|
}
|
|
|
|
char StackSafetyInfoWrapperPass::ID = 0;
|
|
|
|
StackSafetyInfoWrapperPass::StackSafetyInfoWrapperPass() : FunctionPass(ID) {
|
|
initializeStackSafetyInfoWrapperPassPass(*PassRegistry::getPassRegistry());
|
|
}
|
|
|
|
void StackSafetyInfoWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
|
|
AU.addRequired<ScalarEvolutionWrapperPass>();
|
|
AU.setPreservesAll();
|
|
}
|
|
|
|
void StackSafetyInfoWrapperPass::print(raw_ostream &O, const Module *M) const {
|
|
SSI.print(O);
|
|
}
|
|
|
|
bool StackSafetyInfoWrapperPass::runOnFunction(Function &F) {
|
|
StackSafetyLocalAnalysis SSLA(
|
|
F, getAnalysis<ScalarEvolutionWrapperPass>().getSE());
|
|
SSI = StackSafetyInfo(SSLA.run());
|
|
return false;
|
|
}
|
|
|
|
AnalysisKey StackSafetyGlobalAnalysis::Key;
|
|
|
|
StackSafetyGlobalInfo
|
|
StackSafetyGlobalAnalysis::run(Module &M, ModuleAnalysisManager &AM) {
|
|
FunctionAnalysisManager &FAM =
|
|
AM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
|
|
|
|
StackSafetyDataFlowAnalysis SSDFA(
|
|
M, [&FAM](Function &F) -> const StackSafetyInfo & {
|
|
return FAM.getResult<StackSafetyAnalysis>(F);
|
|
});
|
|
return SSDFA.run();
|
|
}
|
|
|
|
PreservedAnalyses StackSafetyGlobalPrinterPass::run(Module &M,
|
|
ModuleAnalysisManager &AM) {
|
|
OS << "'Stack Safety Analysis' for module '" << M.getName() << "'\n";
|
|
print(AM.getResult<StackSafetyGlobalAnalysis>(M), OS, M);
|
|
return PreservedAnalyses::all();
|
|
}
|
|
|
|
static bool SetStackSafetyMetadata(Module &M,
|
|
const StackSafetyGlobalInfo &SSGI) {
|
|
bool Changed = false;
|
|
unsigned Width = M.getDataLayout().getPointerSizeInBits();
|
|
for (auto &F : M.functions()) {
|
|
if (F.isDeclaration() || F.hasOptNone())
|
|
continue;
|
|
auto Iter = SSGI.find(&F);
|
|
if (Iter == SSGI.end())
|
|
continue;
|
|
StackSafetyInfo::FunctionInfo *Summary = Iter->second.getInfo();
|
|
for (auto &AS : Summary->Allocas) {
|
|
ConstantRange AllocaRange{APInt(Width, 0), APInt(Width, AS.Size)};
|
|
if (AllocaRange.contains(AS.Use.Range)) {
|
|
AS.AI->setMetadata(M.getMDKindID("stack-safe"),
|
|
MDNode::get(M.getContext(), None));
|
|
Changed = true;
|
|
}
|
|
}
|
|
}
|
|
return Changed;
|
|
}
|
|
|
|
PreservedAnalyses
|
|
StackSafetyGlobalAnnotatorPass::run(Module &M, ModuleAnalysisManager &AM) {
|
|
auto &SSGI = AM.getResult<StackSafetyGlobalAnalysis>(M);
|
|
(void)SetStackSafetyMetadata(M, SSGI);
|
|
return PreservedAnalyses::all();
|
|
}
|
|
|
|
char StackSafetyGlobalInfoWrapperPass::ID = 0;
|
|
|
|
StackSafetyGlobalInfoWrapperPass::StackSafetyGlobalInfoWrapperPass(bool SetMetadata)
|
|
: ModulePass(ID), SetMetadata(SetMetadata) {
|
|
initializeStackSafetyGlobalInfoWrapperPassPass(
|
|
*PassRegistry::getPassRegistry());
|
|
}
|
|
|
|
void StackSafetyGlobalInfoWrapperPass::print(raw_ostream &O,
|
|
const Module *M) const {
|
|
::print(SSGI, O, *M);
|
|
}
|
|
|
|
void StackSafetyGlobalInfoWrapperPass::getAnalysisUsage(
|
|
AnalysisUsage &AU) const {
|
|
AU.addRequired<StackSafetyInfoWrapperPass>();
|
|
}
|
|
|
|
bool StackSafetyGlobalInfoWrapperPass::runOnModule(Module &M) {
|
|
StackSafetyDataFlowAnalysis SSDFA(
|
|
M, [this](Function &F) -> const StackSafetyInfo & {
|
|
return getAnalysis<StackSafetyInfoWrapperPass>(F).getResult();
|
|
});
|
|
SSGI = SSDFA.run();
|
|
return SetMetadata ? SetStackSafetyMetadata(M, SSGI) : false;
|
|
}
|
|
|
|
ModulePass *llvm::createStackSafetyGlobalInfoWrapperPass(bool SetMetadata) {
|
|
return new StackSafetyGlobalInfoWrapperPass(SetMetadata);
|
|
}
|
|
|
|
static const char LocalPassArg[] = "stack-safety-local";
|
|
static const char LocalPassName[] = "Stack Safety Local Analysis";
|
|
INITIALIZE_PASS_BEGIN(StackSafetyInfoWrapperPass, LocalPassArg, LocalPassName,
|
|
false, true)
|
|
INITIALIZE_PASS_DEPENDENCY(ScalarEvolutionWrapperPass)
|
|
INITIALIZE_PASS_END(StackSafetyInfoWrapperPass, LocalPassArg, LocalPassName,
|
|
false, true)
|
|
|
|
static const char GlobalPassName[] = "Stack Safety Analysis";
|
|
INITIALIZE_PASS_BEGIN(StackSafetyGlobalInfoWrapperPass, DEBUG_TYPE,
|
|
GlobalPassName, false, false)
|
|
INITIALIZE_PASS_DEPENDENCY(StackSafetyInfoWrapperPass)
|
|
INITIALIZE_PASS_END(StackSafetyGlobalInfoWrapperPass, DEBUG_TYPE,
|
|
GlobalPassName, false, false)
|