LLVM  8.0.0svn
StackProtector.cpp
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1 //===- StackProtector.cpp - Stack Protector Insertion ---------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This pass inserts stack protectors into functions which need them. A variable
11 // with a random value in it is stored onto the stack before the local variables
12 // are allocated. Upon exiting the block, the stored value is checked. If it's
13 // changed, then there was some sort of violation and the program aborts.
14 //
15 //===----------------------------------------------------------------------===//
16 
18 #include "llvm/ADT/SmallPtrSet.h"
19 #include "llvm/ADT/Statistic.h"
23 #include "llvm/CodeGen/Passes.h"
27 #include "llvm/IR/Attributes.h"
28 #include "llvm/IR/BasicBlock.h"
29 #include "llvm/IR/Constants.h"
30 #include "llvm/IR/DataLayout.h"
31 #include "llvm/IR/DebugInfo.h"
32 #include "llvm/IR/DebugLoc.h"
33 #include "llvm/IR/DerivedTypes.h"
34 #include "llvm/IR/Dominators.h"
35 #include "llvm/IR/Function.h"
36 #include "llvm/IR/IRBuilder.h"
37 #include "llvm/IR/Instruction.h"
38 #include "llvm/IR/Instructions.h"
39 #include "llvm/IR/IntrinsicInst.h"
40 #include "llvm/IR/Intrinsics.h"
41 #include "llvm/IR/MDBuilder.h"
42 #include "llvm/IR/Module.h"
43 #include "llvm/IR/Type.h"
44 #include "llvm/IR/User.h"
45 #include "llvm/Pass.h"
46 #include "llvm/Support/Casting.h"
50 #include <utility>
51 
52 using namespace llvm;
53 
54 #define DEBUG_TYPE "stack-protector"
55 
56 STATISTIC(NumFunProtected, "Number of functions protected");
57 STATISTIC(NumAddrTaken, "Number of local variables that have their address"
58  " taken.");
59 
60 static cl::opt<bool> EnableSelectionDAGSP("enable-selectiondag-sp",
61  cl::init(true), cl::Hidden);
62 
63 char StackProtector::ID = 0;
64 
66  "Insert stack protectors", false, true)
69  "Insert stack protectors", false, true)
70 
71 FunctionPass *llvm::createStackProtectorPass() { return new StackProtector(); }
72 
76 }
77 
79  F = &Fn;
80  M = F->getParent();
82  getAnalysisIfAvailable<DominatorTreeWrapperPass>();
83  DT = DTWP ? &DTWP->getDomTree() : nullptr;
84  TM = &getAnalysis<TargetPassConfig>().getTM<TargetMachine>();
85  Trip = TM->getTargetTriple();
86  TLI = TM->getSubtargetImpl(Fn)->getTargetLowering();
87  HasPrologue = false;
88  HasIRCheck = false;
89 
90  Attribute Attr = Fn.getFnAttribute("stack-protector-buffer-size");
91  if (Attr.isStringAttribute() &&
92  Attr.getValueAsString().getAsInteger(10, SSPBufferSize))
93  return false; // Invalid integer string
94 
95  if (!RequiresStackProtector())
96  return false;
97 
98  // TODO(etienneb): Functions with funclets are not correctly supported now.
99  // Do nothing if this is funclet-based personality.
100  if (Fn.hasPersonalityFn()) {
102  if (isFuncletEHPersonality(Personality))
103  return false;
104  }
105 
106  ++NumFunProtected;
107  return InsertStackProtectors();
108 }
109 
110 /// \param [out] IsLarge is set to true if a protectable array is found and
111 /// it is "large" ( >= ssp-buffer-size). In the case of a structure with
112 /// multiple arrays, this gets set if any of them is large.
113 bool StackProtector::ContainsProtectableArray(Type *Ty, bool &IsLarge,
114  bool Strong,
115  bool InStruct) const {
116  if (!Ty)
117  return false;
118  if (ArrayType *AT = dyn_cast<ArrayType>(Ty)) {
119  if (!AT->getElementType()->isIntegerTy(8)) {
120  // If we're on a non-Darwin platform or we're inside of a structure, don't
121  // add stack protectors unless the array is a character array.
122  // However, in strong mode any array, regardless of type and size,
123  // triggers a protector.
124  if (!Strong && (InStruct || !Trip.isOSDarwin()))
125  return false;
126  }
127 
128  // If an array has more than SSPBufferSize bytes of allocated space, then we
129  // emit stack protectors.
130  if (SSPBufferSize <= M->getDataLayout().getTypeAllocSize(AT)) {
131  IsLarge = true;
132  return true;
133  }
134 
135  if (Strong)
136  // Require a protector for all arrays in strong mode
137  return true;
138  }
139 
140  const StructType *ST = dyn_cast<StructType>(Ty);
141  if (!ST)
142  return false;
143 
144  bool NeedsProtector = false;
146  E = ST->element_end();
147  I != E; ++I)
148  if (ContainsProtectableArray(*I, IsLarge, Strong, true)) {
149  // If the element is a protectable array and is large (>= SSPBufferSize)
150  // then we are done. If the protectable array is not large, then
151  // keep looking in case a subsequent element is a large array.
152  if (IsLarge)
153  return true;
154  NeedsProtector = true;
155  }
156 
157  return NeedsProtector;
158 }
159 
160 static bool isLifetimeInst(const Instruction *I) {
161  if (const auto Intrinsic = dyn_cast<IntrinsicInst>(I)) {
162  const auto Id = Intrinsic->getIntrinsicID();
163  return Id == Intrinsic::lifetime_start || Id == Intrinsic::lifetime_end;
164  }
165  return false;
166 }
167 
168 bool StackProtector::HasAddressTaken(const Instruction *AI) {
169  for (const User *U : AI->users()) {
170  if (const StoreInst *SI = dyn_cast<StoreInst>(U)) {
171  if (AI == SI->getValueOperand())
172  return true;
173  } else if (const PtrToIntInst *SI = dyn_cast<PtrToIntInst>(U)) {
174  if (AI == SI->getOperand(0))
175  return true;
176  } else if (const CallInst *CI = dyn_cast<CallInst>(U)) {
177  // Ignore intrinsics that are not calls. TODO: Use isLoweredToCall().
178  if (!isa<DbgInfoIntrinsic>(CI) && !isLifetimeInst(CI))
179  return true;
180  } else if (isa<InvokeInst>(U)) {
181  return true;
182  } else if (const SelectInst *SI = dyn_cast<SelectInst>(U)) {
183  if (HasAddressTaken(SI))
184  return true;
185  } else if (const PHINode *PN = dyn_cast<PHINode>(U)) {
186  // Keep track of what PHI nodes we have already visited to ensure
187  // they are only visited once.
188  if (VisitedPHIs.insert(PN).second)
189  if (HasAddressTaken(PN))
190  return true;
191  } else if (const GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(U)) {
192  if (HasAddressTaken(GEP))
193  return true;
194  } else if (const BitCastInst *BI = dyn_cast<BitCastInst>(U)) {
195  if (HasAddressTaken(BI))
196  return true;
197  }
198  }
199  return false;
200 }
201 
202 /// Check whether or not this function needs a stack protector based
203 /// upon the stack protector level.
204 ///
205 /// We use two heuristics: a standard (ssp) and strong (sspstrong).
206 /// The standard heuristic which will add a guard variable to functions that
207 /// call alloca with a either a variable size or a size >= SSPBufferSize,
208 /// functions with character buffers larger than SSPBufferSize, and functions
209 /// with aggregates containing character buffers larger than SSPBufferSize. The
210 /// strong heuristic will add a guard variables to functions that call alloca
211 /// regardless of size, functions with any buffer regardless of type and size,
212 /// functions with aggregates that contain any buffer regardless of type and
213 /// size, and functions that contain stack-based variables that have had their
214 /// address taken.
215 bool StackProtector::RequiresStackProtector() {
216  bool Strong = false;
217  bool NeedsProtector = false;
218  for (const BasicBlock &BB : *F)
219  for (const Instruction &I : BB)
220  if (const CallInst *CI = dyn_cast<CallInst>(&I))
221  if (CI->getCalledFunction() ==
222  Intrinsic::getDeclaration(F->getParent(),
223  Intrinsic::stackprotector))
224  HasPrologue = true;
225 
226  if (F->hasFnAttribute(Attribute::SafeStack))
227  return false;
228 
229  // We are constructing the OptimizationRemarkEmitter on the fly rather than
230  // using the analysis pass to avoid building DominatorTree and LoopInfo which
231  // are not available this late in the IR pipeline.
233 
234  if (F->hasFnAttribute(Attribute::StackProtectReq)) {
235  ORE.emit([&]() {
236  return OptimizationRemark(DEBUG_TYPE, "StackProtectorRequested", F)
237  << "Stack protection applied to function "
238  << ore::NV("Function", F)
239  << " due to a function attribute or command-line switch";
240  });
241  NeedsProtector = true;
242  Strong = true; // Use the same heuristic as strong to determine SSPLayout
243  } else if (F->hasFnAttribute(Attribute::StackProtectStrong))
244  Strong = true;
245  else if (HasPrologue)
246  NeedsProtector = true;
247  else if (!F->hasFnAttribute(Attribute::StackProtect))
248  return false;
249 
250  for (const BasicBlock &BB : *F) {
251  for (const Instruction &I : BB) {
252  if (const AllocaInst *AI = dyn_cast<AllocaInst>(&I)) {
253  if (AI->isArrayAllocation()) {
254  auto RemarkBuilder = [&]() {
255  return OptimizationRemark(DEBUG_TYPE, "StackProtectorAllocaOrArray",
256  &I)
257  << "Stack protection applied to function "
258  << ore::NV("Function", F)
259  << " due to a call to alloca or use of a variable length "
260  "array";
261  };
262  if (const auto *CI = dyn_cast<ConstantInt>(AI->getArraySize())) {
263  if (CI->getLimitedValue(SSPBufferSize) >= SSPBufferSize) {
264  // A call to alloca with size >= SSPBufferSize requires
265  // stack protectors.
266  Layout.insert(std::make_pair(AI,
268  ORE.emit(RemarkBuilder);
269  NeedsProtector = true;
270  } else if (Strong) {
271  // Require protectors for all alloca calls in strong mode.
272  Layout.insert(std::make_pair(AI,
274  ORE.emit(RemarkBuilder);
275  NeedsProtector = true;
276  }
277  } else {
278  // A call to alloca with a variable size requires protectors.
279  Layout.insert(std::make_pair(AI,
281  ORE.emit(RemarkBuilder);
282  NeedsProtector = true;
283  }
284  continue;
285  }
286 
287  bool IsLarge = false;
288  if (ContainsProtectableArray(AI->getAllocatedType(), IsLarge, Strong)) {
289  Layout.insert(std::make_pair(AI, IsLarge
292  ORE.emit([&]() {
293  return OptimizationRemark(DEBUG_TYPE, "StackProtectorBuffer", &I)
294  << "Stack protection applied to function "
295  << ore::NV("Function", F)
296  << " due to a stack allocated buffer or struct containing a "
297  "buffer";
298  });
299  NeedsProtector = true;
300  continue;
301  }
302 
303  if (Strong && HasAddressTaken(AI)) {
304  ++NumAddrTaken;
305  Layout.insert(std::make_pair(AI, MachineFrameInfo::SSPLK_AddrOf));
306  ORE.emit([&]() {
307  return OptimizationRemark(DEBUG_TYPE, "StackProtectorAddressTaken",
308  &I)
309  << "Stack protection applied to function "
310  << ore::NV("Function", F)
311  << " due to the address of a local variable being taken";
312  });
313  NeedsProtector = true;
314  }
315  }
316  }
317  }
318 
319  return NeedsProtector;
320 }
321 
322 /// Create a stack guard loading and populate whether SelectionDAG SSP is
323 /// supported.
325  IRBuilder<> &B,
326  bool *SupportsSelectionDAGSP = nullptr) {
327  if (Value *Guard = TLI->getIRStackGuard(B))
328  return B.CreateLoad(Guard, true, "StackGuard");
329 
330  // Use SelectionDAG SSP handling, since there isn't an IR guard.
331  //
332  // This is more or less weird, since we optionally output whether we
333  // should perform a SelectionDAG SP here. The reason is that it's strictly
334  // defined as !TLI->getIRStackGuard(B), where getIRStackGuard is also
335  // mutating. There is no way to get this bit without mutating the IR, so
336  // getting this bit has to happen in this right time.
337  //
338  // We could have define a new function TLI::supportsSelectionDAGSP(), but that
339  // will put more burden on the backends' overriding work, especially when it
340  // actually conveys the same information getIRStackGuard() already gives.
341  if (SupportsSelectionDAGSP)
342  *SupportsSelectionDAGSP = true;
343  TLI->insertSSPDeclarations(*M);
344  return B.CreateCall(Intrinsic::getDeclaration(M, Intrinsic::stackguard));
345 }
346 
347 /// Insert code into the entry block that stores the stack guard
348 /// variable onto the stack:
349 ///
350 /// entry:
351 /// StackGuardSlot = alloca i8*
352 /// StackGuard = <stack guard>
353 /// call void @llvm.stackprotector(StackGuard, StackGuardSlot)
354 ///
355 /// Returns true if the platform/triple supports the stackprotectorcreate pseudo
356 /// node.
357 static bool CreatePrologue(Function *F, Module *M, ReturnInst *RI,
358  const TargetLoweringBase *TLI, AllocaInst *&AI) {
359  bool SupportsSelectionDAGSP = false;
360  IRBuilder<> B(&F->getEntryBlock().front());
361  PointerType *PtrTy = Type::getInt8PtrTy(RI->getContext());
362  AI = B.CreateAlloca(PtrTy, nullptr, "StackGuardSlot");
363 
364  Value *GuardSlot = getStackGuard(TLI, M, B, &SupportsSelectionDAGSP);
365  B.CreateCall(Intrinsic::getDeclaration(M, Intrinsic::stackprotector),
366  {GuardSlot, AI});
367  return SupportsSelectionDAGSP;
368 }
369 
370 /// InsertStackProtectors - Insert code into the prologue and epilogue of the
371 /// function.
372 ///
373 /// - The prologue code loads and stores the stack guard onto the stack.
374 /// - The epilogue checks the value stored in the prologue against the original
375 /// value. It calls __stack_chk_fail if they differ.
376 bool StackProtector::InsertStackProtectors() {
377  // If the target wants to XOR the frame pointer into the guard value, it's
378  // impossible to emit the check in IR, so the target *must* support stack
379  // protection in SDAG.
380  bool SupportsSelectionDAGSP =
381  TLI->useStackGuardXorFP() ||
383  AllocaInst *AI = nullptr; // Place on stack that stores the stack guard.
384 
385  for (Function::iterator I = F->begin(), E = F->end(); I != E;) {
386  BasicBlock *BB = &*I++;
388  if (!RI)
389  continue;
390 
391  // Generate prologue instrumentation if not already generated.
392  if (!HasPrologue) {
393  HasPrologue = true;
394  SupportsSelectionDAGSP &= CreatePrologue(F, M, RI, TLI, AI);
395  }
396 
397  // SelectionDAG based code generation. Nothing else needs to be done here.
398  // The epilogue instrumentation is postponed to SelectionDAG.
399  if (SupportsSelectionDAGSP)
400  break;
401 
402  // Set HasIRCheck to true, so that SelectionDAG will not generate its own
403  // version. SelectionDAG called 'shouldEmitSDCheck' to check whether
404  // instrumentation has already been generated.
405  HasIRCheck = true;
406 
407  // Generate epilogue instrumentation. The epilogue intrumentation can be
408  // function-based or inlined depending on which mechanism the target is
409  // providing.
410  if (Value* GuardCheck = TLI->getSSPStackGuardCheck(*M)) {
411  // Generate the function-based epilogue instrumentation.
412  // The target provides a guard check function, generate a call to it.
413  IRBuilder<> B(RI);
414  LoadInst *Guard = B.CreateLoad(AI, true, "Guard");
415  CallInst *Call = B.CreateCall(GuardCheck, {Guard});
416  llvm::Function *Function = cast<llvm::Function>(GuardCheck);
417  Call->setAttributes(Function->getAttributes());
418  Call->setCallingConv(Function->getCallingConv());
419  } else {
420  // Generate the epilogue with inline instrumentation.
421  // If we do not support SelectionDAG based tail calls, generate IR level
422  // tail calls.
423  //
424  // For each block with a return instruction, convert this:
425  //
426  // return:
427  // ...
428  // ret ...
429  //
430  // into this:
431  //
432  // return:
433  // ...
434  // %1 = <stack guard>
435  // %2 = load StackGuardSlot
436  // %3 = cmp i1 %1, %2
437  // br i1 %3, label %SP_return, label %CallStackCheckFailBlk
438  //
439  // SP_return:
440  // ret ...
441  //
442  // CallStackCheckFailBlk:
443  // call void @__stack_chk_fail()
444  // unreachable
445 
446  // Create the FailBB. We duplicate the BB every time since the MI tail
447  // merge pass will merge together all of the various BB into one including
448  // fail BB generated by the stack protector pseudo instruction.
449  BasicBlock *FailBB = CreateFailBB();
450 
451  // Split the basic block before the return instruction.
452  BasicBlock *NewBB = BB->splitBasicBlock(RI->getIterator(), "SP_return");
453 
454  // Update the dominator tree if we need to.
455  if (DT && DT->isReachableFromEntry(BB)) {
456  DT->addNewBlock(NewBB, BB);
457  DT->addNewBlock(FailBB, BB);
458  }
459 
460  // Remove default branch instruction to the new BB.
462 
463  // Move the newly created basic block to the point right after the old
464  // basic block so that it's in the "fall through" position.
465  NewBB->moveAfter(BB);
466 
467  // Generate the stack protector instructions in the old basic block.
468  IRBuilder<> B(BB);
469  Value *Guard = getStackGuard(TLI, M, B);
470  LoadInst *LI2 = B.CreateLoad(AI, true);
471  Value *Cmp = B.CreateICmpEQ(Guard, LI2);
472  auto SuccessProb =
474  auto FailureProb =
476  MDNode *Weights = MDBuilder(F->getContext())
477  .createBranchWeights(SuccessProb.getNumerator(),
478  FailureProb.getNumerator());
479  B.CreateCondBr(Cmp, NewBB, FailBB, Weights);
480  }
481  }
482 
483  // Return if we didn't modify any basic blocks. i.e., there are no return
484  // statements in the function.
485  return HasPrologue;
486 }
487 
488 /// CreateFailBB - Create a basic block to jump to when the stack protector
489 /// check fails.
490 BasicBlock *StackProtector::CreateFailBB() {
492  BasicBlock *FailBB = BasicBlock::Create(Context, "CallStackCheckFailBlk", F);
493  IRBuilder<> B(FailBB);
495  if (Trip.isOSOpenBSD()) {
496  Constant *StackChkFail =
497  M->getOrInsertFunction("__stack_smash_handler",
498  Type::getVoidTy(Context),
499  Type::getInt8PtrTy(Context));
500 
501  B.CreateCall(StackChkFail, B.CreateGlobalStringPtr(F->getName(), "SSH"));
502  } else {
503  Constant *StackChkFail =
504  M->getOrInsertFunction("__stack_chk_fail", Type::getVoidTy(Context));
505 
506  B.CreateCall(StackChkFail, {});
507  }
508  B.CreateUnreachable();
509  return FailBB;
510 }
511 
513  return HasPrologue && !HasIRCheck && dyn_cast<ReturnInst>(BB.getTerminator());
514 }
515 
517  if (Layout.empty())
518  return;
519 
520  for (int I = 0, E = MFI.getObjectIndexEnd(); I != E; ++I) {
521  if (MFI.isDeadObjectIndex(I))
522  continue;
523 
524  const AllocaInst *AI = MFI.getObjectAllocation(I);
525  if (!AI)
526  continue;
527 
528  SSPLayoutMap::const_iterator LI = Layout.find(AI);
529  if (LI == Layout.end())
530  continue;
531 
532  MFI.setObjectSSPLayout(I, LI->second);
533  }
534 }
Return a value (possibly void), from a function.
bool isOSDarwin() const
isOSDarwin - Is this a "Darwin" OS (OS X, iOS, or watchOS).
Definition: Triple.h:474
SymbolTableList< Instruction >::iterator eraseFromParent()
This method unlinks &#39;this&#39; from the containing basic block and deletes it.
Definition: Instruction.cpp:68
BranchInst * CreateCondBr(Value *Cond, BasicBlock *True, BasicBlock *False, MDNode *BranchWeights=nullptr, MDNode *Unpredictable=nullptr)
Create a conditional &#39;br Cond, TrueDest, FalseDest&#39; instruction.
Definition: IRBuilder.h:854
AnalysisUsage & addPreserved()
Add the specified Pass class to the set of analyses preserved by this pass.
DILocation * get() const
Get the underlying DILocation.
Definition: DebugLoc.cpp:22
LLVMContext & Context
DiagnosticInfoOptimizationBase::Argument NV
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
Constant * getOrInsertFunction(StringRef Name, FunctionType *T, AttributeList AttributeList)
Look up the specified function in the module symbol table.
Definition: Module.cpp:143
unsigned EnableFastISel
EnableFastISel - This flag enables fast-path instruction selection which trades away generated code q...
A Module instance is used to store all the information related to an LLVM module. ...
Definition: Module.h:64
iterator end()
Definition: Function.h:658
bool isDeadObjectIndex(int ObjectIdx) const
Returns true if the specified index corresponds to a dead object.
This class represents a function call, abstracting a target machine&#39;s calling convention.
virtual const TargetLowering * getTargetLowering() const
void copyToMachineFrameInfo(MachineFrameInfo &MFI) const
LLVMContext & getContext() const
All values hold a context through their type.
Definition: Value.cpp:714
STATISTIC(NumFunctions, "Total number of functions")
Metadata node.
Definition: Metadata.h:864
block Block Frequency true
An instruction for reading from memory.
Definition: Instructions.h:168
static bool isLifetimeInst(const Instruction *I)
Hexagon Common GEP
const Instruction * getTerminator() const LLVM_READONLY
Returns the terminator instruction if the block is well formed or null if the block is not well forme...
Definition: BasicBlock.cpp:138
bool isReachableFromEntry(const Use &U) const
Provide an overload for a Use.
Definition: Dominators.cpp:300
static bool CreatePrologue(Function *F, Module *M, ReturnInst *RI, const TargetLoweringBase *TLI, AllocaInst *&AI)
Insert code into the entry block that stores the stack guard variable onto the stack: ...
std::pair< iterator, bool > insert(const std::pair< KeyT, ValueT > &KV)
Definition: DenseMap.h:196
AnalysisUsage & addRequired()
#define INITIALIZE_PASS_DEPENDENCY(depName)
Definition: PassSupport.h:51
This class represents the LLVM &#39;select&#39; instruction.
bool isStringAttribute() const
Return true if the attribute is a string (target-dependent) attribute.
Definition: Attributes.cpp:170
Class to represent struct types.
Definition: DerivedTypes.h:201
static cl::opt< bool > EnableSelectionDAGSP("enable-selectiondag-sp", cl::init(true), cl::Hidden)
The address of this allocation is exposed and triggered protection.
This provides a uniform API for creating instructions and inserting them into a basic block: either a...
Definition: IRBuilder.h:743
This file contains the simple types necessary to represent the attributes associated with functions a...
The MachineFrameInfo class represents an abstract stack frame until prolog/epilog code is inserted...
DominatorTree & getDomTree()
Definition: Dominators.h:270
Target-Independent Code Generator Pass Configuration Options.
This class represents a cast from a pointer to an integer.
Class to represent array types.
Definition: DerivedTypes.h:369
void setAttributes(AttributeList A)
Set the parameter attributes for this call.
This class represents a no-op cast from one type to another.
int getObjectIndexEnd() const
Return one past the maximum frame object index.
AttributeList getAttributes() const
Return the attribute list for this Function.
Definition: Function.h:224
An instruction for storing to memory.
Definition: Instructions.h:310
bool hasPersonalityFn() const
Check whether this function has a personality function.
Definition: Function.h:702
void SetCurrentDebugLocation(DebugLoc L)
Set location information used by debugging information.
Definition: IRBuilder.h:151
iterator begin()
Definition: Function.h:656
Type::subtype_iterator element_iterator
Definition: DerivedTypes.h:301
Function * getDeclaration(Module *M, ID id, ArrayRef< Type *> Tys=None)
Create or insert an LLVM Function declaration for an intrinsic, and return it.
Definition: Function.cpp:1021
Class to represent pointers.
Definition: DerivedTypes.h:467
bool runOnFunction(Function &Fn) override
runOnFunction - Virtual method overriden by subclasses to do the per-function processing of the pass...
#define DEBUG_TYPE
void setObjectSSPLayout(int ObjectIdx, SSPLayoutKind Kind)
Array or nested array >= SSP-buffer-size.
void getAnalysisUsage(AnalysisUsage &AU) const override
getAnalysisUsage - This function should be overriden by passes that need analysis information to do t...
iterator find(const_arg_type_t< KeyT > Val)
Definition: DenseMap.h:151
const BasicBlock & getEntryBlock() const
Definition: Function.h:640
virtual Value * getIRStackGuard(IRBuilder<> &IRB) const
If the target has a standard location for the stack protector guard, returns the address of that loca...
an instruction for type-safe pointer arithmetic to access elements of arrays and structs ...
Definition: Instructions.h:843
LoadInst * CreateLoad(Value *Ptr, const char *Name)
Provided to resolve &#39;CreateLoad(Ptr, "...")&#39; correctly, instead of converting the string to &#39;bool&#39; fo...
Definition: IRBuilder.h:1317
initializer< Ty > init(const Ty &Val)
Definition: CommandLine.h:410
static GCRegistry::Add< OcamlGC > B("ocaml", "ocaml 3.10-compatible GC")
LLVM Basic Block Representation.
Definition: BasicBlock.h:58
The instances of the Type class are immutable: once they are created, they are never changed...
Definition: Type.h:46
This is an important class for using LLVM in a threaded context.
Definition: LLVMContext.h:69
UnreachableInst * CreateUnreachable()
Definition: IRBuilder.h:938
DISubprogram * getSubprogram() const
Get the attached subprogram.
Definition: Metadata.cpp:1508
bool isOSOpenBSD() const
Definition: Triple.h:486
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
This is an important base class in LLVM.
Definition: Constant.h:42
This file contains the declarations for the subclasses of Constant, which represent the different fla...
const Instruction & front() const
Definition: BasicBlock.h:275
Diagnostic information for applied optimization remarks.
element_iterator element_end() const
Definition: DerivedTypes.h:304
EHPersonality classifyEHPersonality(const Value *Pers)
See if the given exception handling personality function is one that we understand.
Represent the analysis usage information of a pass.
static Type * getVoidTy(LLVMContext &C)
Definition: Type.cpp:161
FunctionPass class - This class is used to implement most global optimizations.
Definition: Pass.h:285
const Triple & getTargetTriple() const
static BasicBlock * Create(LLVMContext &Context, const Twine &Name="", Function *Parent=nullptr, BasicBlock *InsertBefore=nullptr)
Creates a new BasicBlock.
Definition: BasicBlock.h:100
Value * CreateICmpEQ(Value *LHS, Value *RHS, const Twine &Name="")
Definition: IRBuilder.h:1748
self_iterator getIterator()
Definition: ilist_node.h:82
FunctionPass * createStackProtectorPass()
createStackProtectorPass - This pass adds stack protectors to functions.
LLVMContext & getContext() const
getContext - Return a reference to the LLVMContext associated with this function. ...
Definition: Function.cpp:194
static PointerType * getInt8PtrTy(LLVMContext &C, unsigned AS=0)
Definition: Type.cpp:220
virtual bool useStackGuardXorFP() const
If this function returns true, stack protection checks should XOR the frame pointer (or whichever poi...
INITIALIZE_PASS_END(RegBankSelect, DEBUG_TYPE, "Assign register bank of generic virtual registers", false, false) RegBankSelect
void setCallingConv(CallingConv::ID CC)
This base class for TargetLowering contains the SelectionDAG-independent parts that can be used from ...
std::enable_if< std::numeric_limits< T >::is_signed, bool >::type getAsInteger(unsigned Radix, T &Result) const
Parse the current string as an integer of the specified radix.
Definition: StringRef.h:497
Iterator for intrusive lists based on ilist_node.
void moveAfter(BasicBlock *MovePos)
Unlink this basic block from its current function and insert it right after MovePos in the function M...
Definition: BasicBlock.cpp:128
void emit(DiagnosticInfoOptimizationBase &OptDiag)
Output the remark via the diagnostic handler and to the optimization record file. ...
bool isFuncletEHPersonality(EHPersonality Pers)
Returns true if this is a personality function that invokes handler funclets (which must return to it...
Insert stack protectors
CallingConv::ID getCallingConv() const
getCallingConv()/setCallingConv(CC) - These method get and set the calling convention of this functio...
Definition: Function.h:213
Module.h This file contains the declarations for the Module class.
virtual const TargetSubtargetInfo * getSubtargetImpl(const Function &) const
Virtual method implemented by subclasses that returns a reference to that target&#39;s TargetSubtargetInf...
Constant * CreateGlobalStringPtr(StringRef Str, const Twine &Name="", unsigned AddressSpace=0)
Same as CreateGlobalString, but return a pointer with "i8*" type instead of a pointer to array of i8...
Definition: IRBuilder.h:1551
iterator_range< user_iterator > users()
Definition: Value.h:400
element_iterator element_begin() const
Definition: DerivedTypes.h:303
virtual Value * getSSPStackGuardCheck(const Module &M) const
If the target has a standard stack protection check function that performs validation and error handl...
const AllocaInst * getObjectAllocation(int ObjectIdx) const
Return the underlying Alloca of the specified stack object if it exists.
INITIALIZE_PASS_BEGIN(StackProtector, DEBUG_TYPE, "Insert stack protectors", false, true) INITIALIZE_PASS_END(StackProtector
StringRef getValueAsString() const
Return the attribute&#39;s value as a string.
Definition: Attributes.cpp:195
StringRef getName() const
Return a constant reference to the value&#39;s name.
Definition: Value.cpp:224
TargetOptions Options
Definition: TargetMachine.h:97
#define I(x, y, z)
Definition: MD5.cpp:58
DomTreeNodeBase< NodeT > * addNewBlock(NodeT *BB, NodeT *DomBB)
Add a new node to the dominator tree information.
iterator end()
Definition: DenseMap.h:84
LLVM_NODISCARD std::enable_if<!is_simple_type< Y >::value, typename cast_retty< X, const Y >::ret_type >::type dyn_cast(const Y &Val)
Definition: Casting.h:323
BasicBlock * splitBasicBlock(iterator I, const Twine &BBName="")
Split the basic block into two basic blocks at the specified instruction.
Definition: BasicBlock.cpp:402
LLVM_NODISCARD bool empty() const
Definition: DenseMap.h:98
Module * getParent()
Get the module that this global value is contained inside of...
Definition: GlobalValue.h:566
LLVM Value Representation.
Definition: Value.h:73
Constant * getPersonalityFn() const
Get the personality function associated with this function.
Definition: Function.cpp:1302
Array or nested array < SSP-buffer-size.
virtual void insertSSPDeclarations(Module &M) const
Inserts necessary declarations for SSP (stack protection) purpose.
Attribute getFnAttribute(Attribute::AttrKind Kind) const
Return the attribute for the given attribute kind.
Definition: Function.h:331
Legacy analysis pass which computes a DominatorTree.
Definition: Dominators.h:260
static Value * getStackGuard(const TargetLoweringBase *TLI, Module *M, IRBuilder<> &B, bool *SupportsSelectionDAGSP=nullptr)
Create a stack guard loading and populate whether SelectionDAG SSP is supported.
bool shouldEmitSDCheck(const BasicBlock &BB) const
The optimization diagnostic interface.
static BranchProbability getBranchProbStackProtector(bool IsLikely)
This file describes how to lower LLVM code to machine code.
an instruction to allocate memory on the stack
Definition: Instructions.h:60
CallInst * CreateCall(Value *Callee, ArrayRef< Value *> Args=None, const Twine &Name="", MDNode *FPMathTag=nullptr)
Definition: IRBuilder.h:1883