LLVM  9.0.0svn
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 bool StackProtector::HasAddressTaken(const Instruction *AI) {
161  for (const User *U : AI->users()) {
162  if (const StoreInst *SI = dyn_cast<StoreInst>(U)) {
163  if (AI == SI->getValueOperand())
164  return true;
165  } else if (const PtrToIntInst *SI = dyn_cast<PtrToIntInst>(U)) {
166  if (AI == SI->getOperand(0))
167  return true;
168  } else if (const CallInst *CI = dyn_cast<CallInst>(U)) {
169  // Ignore intrinsics that are not calls. TODO: Use isLoweredToCall().
170  if (!isa<DbgInfoIntrinsic>(CI) && !CI->isLifetimeStartOrEnd())
171  return true;
172  } else if (isa<InvokeInst>(U)) {
173  return true;
174  } else if (const SelectInst *SI = dyn_cast<SelectInst>(U)) {
175  if (HasAddressTaken(SI))
176  return true;
177  } else if (const PHINode *PN = dyn_cast<PHINode>(U)) {
178  // Keep track of what PHI nodes we have already visited to ensure
179  // they are only visited once.
180  if (VisitedPHIs.insert(PN).second)
181  if (HasAddressTaken(PN))
182  return true;
183  } else if (const GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(U)) {
184  if (HasAddressTaken(GEP))
185  return true;
186  } else if (const BitCastInst *BI = dyn_cast<BitCastInst>(U)) {
187  if (HasAddressTaken(BI))
188  return true;
189  }
190  }
191  return false;
192 }
193 
194 /// Search for the first call to the llvm.stackprotector intrinsic and return it
195 /// if present.
197  for (const BasicBlock &BB : F)
198  for (const Instruction &I : BB)
199  if (const CallInst *CI = dyn_cast<CallInst>(&I))
200  if (CI->getCalledFunction() ==
201  Intrinsic::getDeclaration(F.getParent(), Intrinsic::stackprotector))
202  return CI;
203  return nullptr;
204 }
205 
206 /// Check whether or not this function needs a stack protector based
207 /// upon the stack protector level.
208 ///
209 /// We use two heuristics: a standard (ssp) and strong (sspstrong).
210 /// The standard heuristic which will add a guard variable to functions that
211 /// call alloca with a either a variable size or a size >= SSPBufferSize,
212 /// functions with character buffers larger than SSPBufferSize, and functions
213 /// with aggregates containing character buffers larger than SSPBufferSize. The
214 /// strong heuristic will add a guard variables to functions that call alloca
215 /// regardless of size, functions with any buffer regardless of type and size,
216 /// functions with aggregates that contain any buffer regardless of type and
217 /// size, and functions that contain stack-based variables that have had their
218 /// address taken.
219 bool StackProtector::RequiresStackProtector() {
220  bool Strong = false;
221  bool NeedsProtector = false;
222  HasPrologue = findStackProtectorIntrinsic(*F);
223 
224  if (F->hasFnAttribute(Attribute::SafeStack))
225  return false;
226 
227  // We are constructing the OptimizationRemarkEmitter on the fly rather than
228  // using the analysis pass to avoid building DominatorTree and LoopInfo which
229  // are not available this late in the IR pipeline.
231 
232  if (F->hasFnAttribute(Attribute::StackProtectReq)) {
233  ORE.emit([&]() {
234  return OptimizationRemark(DEBUG_TYPE, "StackProtectorRequested", F)
235  << "Stack protection applied to function "
236  << ore::NV("Function", F)
237  << " due to a function attribute or command-line switch";
238  });
239  NeedsProtector = true;
240  Strong = true; // Use the same heuristic as strong to determine SSPLayout
241  } else if (F->hasFnAttribute(Attribute::StackProtectStrong))
242  Strong = true;
243  else if (HasPrologue)
244  NeedsProtector = true;
245  else if (!F->hasFnAttribute(Attribute::StackProtect))
246  return false;
247 
248  for (const BasicBlock &BB : *F) {
249  for (const Instruction &I : BB) {
250  if (const AllocaInst *AI = dyn_cast<AllocaInst>(&I)) {
251  if (AI->isArrayAllocation()) {
252  auto RemarkBuilder = [&]() {
253  return OptimizationRemark(DEBUG_TYPE, "StackProtectorAllocaOrArray",
254  &I)
255  << "Stack protection applied to function "
256  << ore::NV("Function", F)
257  << " due to a call to alloca or use of a variable length "
258  "array";
259  };
260  if (const auto *CI = dyn_cast<ConstantInt>(AI->getArraySize())) {
261  if (CI->getLimitedValue(SSPBufferSize) >= SSPBufferSize) {
262  // A call to alloca with size >= SSPBufferSize requires
263  // stack protectors.
264  Layout.insert(std::make_pair(AI,
266  ORE.emit(RemarkBuilder);
267  NeedsProtector = true;
268  } else if (Strong) {
269  // Require protectors for all alloca calls in strong mode.
270  Layout.insert(std::make_pair(AI,
272  ORE.emit(RemarkBuilder);
273  NeedsProtector = true;
274  }
275  } else {
276  // A call to alloca with a variable size requires protectors.
277  Layout.insert(std::make_pair(AI,
279  ORE.emit(RemarkBuilder);
280  NeedsProtector = true;
281  }
282  continue;
283  }
284 
285  bool IsLarge = false;
286  if (ContainsProtectableArray(AI->getAllocatedType(), IsLarge, Strong)) {
287  Layout.insert(std::make_pair(AI, IsLarge
290  ORE.emit([&]() {
291  return OptimizationRemark(DEBUG_TYPE, "StackProtectorBuffer", &I)
292  << "Stack protection applied to function "
293  << ore::NV("Function", F)
294  << " due to a stack allocated buffer or struct containing a "
295  "buffer";
296  });
297  NeedsProtector = true;
298  continue;
299  }
300 
301  if (Strong && HasAddressTaken(AI)) {
302  ++NumAddrTaken;
303  Layout.insert(std::make_pair(AI, MachineFrameInfo::SSPLK_AddrOf));
304  ORE.emit([&]() {
305  return OptimizationRemark(DEBUG_TYPE, "StackProtectorAddressTaken",
306  &I)
307  << "Stack protection applied to function "
308  << ore::NV("Function", F)
309  << " due to the address of a local variable being taken";
310  });
311  NeedsProtector = true;
312  }
313  }
314  }
315  }
316 
317  return NeedsProtector;
318 }
319 
320 /// Create a stack guard loading and populate whether SelectionDAG SSP is
321 /// supported.
323  IRBuilder<> &B,
324  bool *SupportsSelectionDAGSP = nullptr) {
325  if (Value *Guard = TLI->getIRStackGuard(B))
326  return B.CreateLoad(Guard, true, "StackGuard");
327 
328  // Use SelectionDAG SSP handling, since there isn't an IR guard.
329  //
330  // This is more or less weird, since we optionally output whether we
331  // should perform a SelectionDAG SP here. The reason is that it's strictly
332  // defined as !TLI->getIRStackGuard(B), where getIRStackGuard is also
333  // mutating. There is no way to get this bit without mutating the IR, so
334  // getting this bit has to happen in this right time.
335  //
336  // We could have define a new function TLI::supportsSelectionDAGSP(), but that
337  // will put more burden on the backends' overriding work, especially when it
338  // actually conveys the same information getIRStackGuard() already gives.
339  if (SupportsSelectionDAGSP)
340  *SupportsSelectionDAGSP = true;
341  TLI->insertSSPDeclarations(*M);
342  return B.CreateCall(Intrinsic::getDeclaration(M, Intrinsic::stackguard));
343 }
344 
345 /// Insert code into the entry block that stores the stack guard
346 /// variable onto the stack:
347 ///
348 /// entry:
349 /// StackGuardSlot = alloca i8*
350 /// StackGuard = <stack guard>
351 /// call void @llvm.stackprotector(StackGuard, StackGuardSlot)
352 ///
353 /// Returns true if the platform/triple supports the stackprotectorcreate pseudo
354 /// node.
355 static bool CreatePrologue(Function *F, Module *M, ReturnInst *RI,
356  const TargetLoweringBase *TLI, AllocaInst *&AI) {
357  bool SupportsSelectionDAGSP = false;
358  IRBuilder<> B(&F->getEntryBlock().front());
359  PointerType *PtrTy = Type::getInt8PtrTy(RI->getContext());
360  AI = B.CreateAlloca(PtrTy, nullptr, "StackGuardSlot");
361 
362  Value *GuardSlot = getStackGuard(TLI, M, B, &SupportsSelectionDAGSP);
363  B.CreateCall(Intrinsic::getDeclaration(M, Intrinsic::stackprotector),
364  {GuardSlot, AI});
365  return SupportsSelectionDAGSP;
366 }
367 
368 /// InsertStackProtectors - Insert code into the prologue and epilogue of the
369 /// function.
370 ///
371 /// - The prologue code loads and stores the stack guard onto the stack.
372 /// - The epilogue checks the value stored in the prologue against the original
373 /// value. It calls __stack_chk_fail if they differ.
374 bool StackProtector::InsertStackProtectors() {
375  // If the target wants to XOR the frame pointer into the guard value, it's
376  // impossible to emit the check in IR, so the target *must* support stack
377  // protection in SDAG.
378  bool SupportsSelectionDAGSP =
379  TLI->useStackGuardXorFP() ||
382  AllocaInst *AI = nullptr; // Place on stack that stores the stack guard.
383 
384  for (Function::iterator I = F->begin(), E = F->end(); I != E;) {
385  BasicBlock *BB = &*I++;
387  if (!RI)
388  continue;
389 
390  // Generate prologue instrumentation if not already generated.
391  if (!HasPrologue) {
392  HasPrologue = true;
393  SupportsSelectionDAGSP &= CreatePrologue(F, M, RI, TLI, AI);
394  }
395 
396  // SelectionDAG based code generation. Nothing else needs to be done here.
397  // The epilogue instrumentation is postponed to SelectionDAG.
398  if (SupportsSelectionDAGSP)
399  break;
400 
401  // Find the stack guard slot if the prologue was not created by this pass
402  // itself via a previous call to CreatePrologue().
403  if (!AI) {
404  const CallInst *SPCall = findStackProtectorIntrinsic(*F);
405  assert(SPCall && "Call to llvm.stackprotector is missing");
406  AI = cast<AllocaInst>(SPCall->getArgOperand(1));
407  }
408 
409  // Set HasIRCheck to true, so that SelectionDAG will not generate its own
410  // version. SelectionDAG called 'shouldEmitSDCheck' to check whether
411  // instrumentation has already been generated.
412  HasIRCheck = true;
413 
414  // Generate epilogue instrumentation. The epilogue intrumentation can be
415  // function-based or inlined depending on which mechanism the target is
416  // providing.
417  if (Value* GuardCheck = TLI->getSSPStackGuardCheck(*M)) {
418  // Generate the function-based epilogue instrumentation.
419  // The target provides a guard check function, generate a call to it.
420  IRBuilder<> B(RI);
421  LoadInst *Guard = B.CreateLoad(AI, true, "Guard");
422  CallInst *Call = B.CreateCall(GuardCheck, {Guard});
423  llvm::Function *Function = cast<llvm::Function>(GuardCheck);
424  Call->setAttributes(Function->getAttributes());
425  Call->setCallingConv(Function->getCallingConv());
426  } else {
427  // Generate the epilogue with inline instrumentation.
428  // If we do not support SelectionDAG based tail calls, generate IR level
429  // tail calls.
430  //
431  // For each block with a return instruction, convert this:
432  //
433  // return:
434  // ...
435  // ret ...
436  //
437  // into this:
438  //
439  // return:
440  // ...
441  // %1 = <stack guard>
442  // %2 = load StackGuardSlot
443  // %3 = cmp i1 %1, %2
444  // br i1 %3, label %SP_return, label %CallStackCheckFailBlk
445  //
446  // SP_return:
447  // ret ...
448  //
449  // CallStackCheckFailBlk:
450  // call void @__stack_chk_fail()
451  // unreachable
452 
453  // Create the FailBB. We duplicate the BB every time since the MI tail
454  // merge pass will merge together all of the various BB into one including
455  // fail BB generated by the stack protector pseudo instruction.
456  BasicBlock *FailBB = CreateFailBB();
457 
458  // Split the basic block before the return instruction.
459  BasicBlock *NewBB = BB->splitBasicBlock(RI->getIterator(), "SP_return");
460 
461  // Update the dominator tree if we need to.
462  if (DT && DT->isReachableFromEntry(BB)) {
463  DT->addNewBlock(NewBB, BB);
464  DT->addNewBlock(FailBB, BB);
465  }
466 
467  // Remove default branch instruction to the new BB.
469 
470  // Move the newly created basic block to the point right after the old
471  // basic block so that it's in the "fall through" position.
472  NewBB->moveAfter(BB);
473 
474  // Generate the stack protector instructions in the old basic block.
475  IRBuilder<> B(BB);
476  Value *Guard = getStackGuard(TLI, M, B);
477  LoadInst *LI2 = B.CreateLoad(AI, true);
478  Value *Cmp = B.CreateICmpEQ(Guard, LI2);
479  auto SuccessProb =
481  auto FailureProb =
483  MDNode *Weights = MDBuilder(F->getContext())
484  .createBranchWeights(SuccessProb.getNumerator(),
485  FailureProb.getNumerator());
486  B.CreateCondBr(Cmp, NewBB, FailBB, Weights);
487  }
488  }
489 
490  // Return if we didn't modify any basic blocks. i.e., there are no return
491  // statements in the function.
492  return HasPrologue;
493 }
494 
495 /// CreateFailBB - Create a basic block to jump to when the stack protector
496 /// check fails.
497 BasicBlock *StackProtector::CreateFailBB() {
499  BasicBlock *FailBB = BasicBlock::Create(Context, "CallStackCheckFailBlk", F);
500  IRBuilder<> B(FailBB);
502  if (Trip.isOSOpenBSD()) {
503  Constant *StackChkFail =
504  M->getOrInsertFunction("__stack_smash_handler",
505  Type::getVoidTy(Context),
506  Type::getInt8PtrTy(Context));
507 
508  B.CreateCall(StackChkFail, B.CreateGlobalStringPtr(F->getName(), "SSH"));
509  } else {
510  Constant *StackChkFail =
511  M->getOrInsertFunction("__stack_chk_fail", Type::getVoidTy(Context));
512 
513  B.CreateCall(StackChkFail, {});
514  }
515  B.CreateUnreachable();
516  return FailBB;
517 }
518 
520  return HasPrologue && !HasIRCheck && dyn_cast<ReturnInst>(BB.getTerminator());
521 }
522 
524  if (Layout.empty())
525  return;
526 
527  for (int I = 0, E = MFI.getObjectIndexEnd(); I != E; ++I) {
528  if (MFI.isDeadObjectIndex(I))
529  continue;
530 
531  const AllocaInst *AI = MFI.getObjectAllocation(I);
532  if (!AI)
533  continue;
534 
535  SSPLayoutMap::const_iterator LI = Layout.find(AI);
536  if (LI == Layout.end())
537  continue;
538 
539  MFI.setObjectSSPLayout(I, LI->second);
540  }
541 }
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:475
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
This class represents lattice values for constants.
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:144
LoadInst * CreateLoad(Type *Ty, Value *Ptr, const char *Name)
Provided to resolve &#39;CreateLoad(Ty, Ptr, "...")&#39; correctly, instead of converting the string to &#39;bool...
Definition: IRBuilder.h:1357
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:65
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:705
bool hasFnAttribute(Attribute::AttrKind Kind) const
Return true if the function has the attribute.
Definition: Function.h:321
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
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: ...
Value * getArgOperand(unsigned i) const
Definition: InstrTypes.h:1135
std::pair< iterator, bool > insert(const std::pair< KeyT, ValueT > &KV)
Definition: DenseMap.h:221
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
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:321
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:1020
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:176
unsigned EnableGlobalISel
EnableGlobalISel - This flag enables global instruction selection.
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:854
initializer< Ty > init(const Ty &Val)
Definition: CommandLine.h:423
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:978
DISubprogram * getSubprogram() const
Get the attached subprogram.
Definition: Metadata.cpp:1508
bool isOSOpenBSD() const
Definition: Triple.h:487
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:281
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
void setCallingConv(CallingConv::ID CC)
Definition: InstrTypes.h:1229
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:1839
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:193
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
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
static const CallInst * findStackProtectorIntrinsic(Function &F)
Search for the first call to the llvm.stackprotector intrinsic and return it if present.
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:1642
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:214
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:109
void setAttributes(AttributeList A)
Set the parameter attributes for this call.
Definition: InstrTypes.h:1248
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
CallInst * CreateCall(FunctionType *FTy, Value *Callee, ArrayRef< Value *> Args=None, const Twine &Name="", MDNode *FPMathTag=nullptr)
Definition: IRBuilder.h:1974
BasicBlock * splitBasicBlock(iterator I, const Twine &BBName="")
Split the basic block into two basic blocks at the specified instruction.
Definition: BasicBlock.cpp:408
LLVM_NODISCARD bool empty() const
Definition: DenseMap.h:123
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
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:1299
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