StackProtector.cpp File Reference

#include "llvm/CodeGen/StackProtector.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/BranchProbabilityInfo.h"
#include "llvm/Analysis/MemoryLocation.h"
#include "llvm/Analysis/OptimizationRemarkEmitter.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/CodeGen/TargetPassConfig.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/EHPersonalities.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/User.h"
#include "llvm/InitializePasses.h"
#include "llvm/Pass.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include <optional>
#include <utility>

Include dependency graph for StackProtector.cpp:

Go to the source code of this file.

Macros
#define	DEBUG_TYPE   "stack-protector"

Functions
	STATISTIC (NumFunProtected, "Number of functions protected")
	STATISTIC (NumAddrTaken, "Number of local variables that have their address" " taken.")
	INITIALIZE_PASS_BEGIN (StackProtector, DEBUG_TYPE, "Insert stack protectors", false, true) INITIALIZE_PASS_END(StackProtector
static bool	ContainsProtectableArray (Type *Ty, Module *M, unsigned SSPBufferSize, bool &IsLarge, bool Strong, bool InStruct)
static bool	HasAddressTaken (const Instruction *AI, TypeSize AllocSize, Module *M, SmallPtrSet< const PHINode *, 16 > &VisitedPHIs)
	Check whether a stack allocation has its address taken.
static const CallInst *	findStackProtectorIntrinsic (Function &F)
	Search for the first call to the llvm.stackprotector intrinsic and return it if present.
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.
static bool	CreatePrologue (Function *F, Module *M, Instruction *CheckLoc, const TargetLoweringBase *TLI, AllocaInst *&AI)
	Insert code into the entry block that stores the stack guard variable onto the stack:

Variables
static cl::opt< bool >	EnableSelectionDAGSP ("enable-selectiondag-sp", cl::init(true), cl::Hidden)
static cl::opt< bool >	DisableCheckNoReturn ("disable-check-noreturn-call", cl::init(false), cl::Hidden)
	DEBUG_TYPE
Insert stack	protectors
Insert stack	false

Macro Definition Documentation

DEBUG_TYPE

#define DEBUG_TYPE   "stack-protector"

Definition at line 55 of file StackProtector.cpp.

Function Documentation

ContainsProtectableArray()

static bool ContainsProtectableArray ( Type *  Ty, Module *  M, unsigned  SSPBufferSize, bool &  IsLarge, bool  Strong, bool  InStruct  )

static

Parameters

[out]

IsLarge

is set to true if a protectable array is found and it is "large" ( >= ssp-buffer-size). In the case of a structure with multiple arrays, this gets set if any of them is large.

Definition at line 124 of file StackProtector.cpp.

References ContainsProtectableArray(), and llvm::Triple::isOSDarwin().

Referenced by ContainsProtectableArray(), and llvm::StackProtector::requiresStackProtector().

CreatePrologue()

static bool CreatePrologue ( Function *  F, Module *  M, Instruction *  CheckLoc, const TargetLoweringBase *  TLI, AllocaInst *&  AI  )

static

Insert code into the entry block that stores the stack guard variable onto the stack:

entry: StackGuardSlot = alloca i8* StackGuard = <stack guard> call void @llvm.stackprotector(StackGuard, StackGuardSlot)

Returns true if the platform/triple supports the stackprotectorcreate pseudo node.

Definition at line 450 of file StackProtector.cpp.

References B, F, llvm::Value::getContext(), llvm::Intrinsic::getDeclaration(), llvm::Type::getInt8PtrTy(), and getStackGuard().

findStackProtectorIntrinsic()

static const CallInst * findStackProtectorIntrinsic ( Function &  F )

static

Search for the first call to the llvm.stackprotector intrinsic and return it if present.

Definition at line 265 of file StackProtector.cpp.

References F, and I.

getStackGuard()

static Value * getStackGuard ( const TargetLoweringBase *  TLI, Module *  M, IRBuilder<> &  B, bool *  SupportsSelectionDAGSP = nullptr  )

static

Create a stack guard loading and populate whether SelectionDAG SSP is supported.

Definition at line 415 of file StackProtector.cpp.

References B, llvm::StringRef::empty(), llvm::Intrinsic::getDeclaration(), llvm::TargetLoweringBase::getIRStackGuard(), and llvm::TargetLoweringBase::insertSSPDeclarations().

Referenced by CreatePrologue().

HasAddressTaken()

static bool HasAddressTaken ( const Instruction *  AI, TypeSize  AllocSize, Module *  M, SmallPtrSet< const PHINode *, 16 > &  VisitedPHIs  )

static

Check whether a stack allocation has its address taken.

Definition at line 170 of file StackProtector.cpp.

References DL, llvm::TypeSize::Fixed(), GEP, llvm::TypeSize::getFixed(), llvm::details::FixedOrScalableQuantity< LeafTy, ValueTy >::getKnownMinValue(), llvm::MemoryLocation::getOrNone(), HasAddressTaken(), I, llvm::SmallPtrSetImpl< PtrType >::insert(), llvm::details::FixedOrScalableQuantity< TypeSize, uint64_t >::isKnownGE(), llvm::details::FixedOrScalableQuantity< TypeSize, uint64_t >::isKnownGT(), llvm::Offset, and llvm::Value::users().

Referenced by HasAddressTaken(), and llvm::StackProtector::requiresStackProtector().

INITIALIZE_PASS_BEGIN()

INITIALIZE_PASS_BEGIN	(	StackProtector	,
		DEBUG_TYPE	,
		"Insert stack protectors"	,
		false	,
		true
	)

STATISTIC() [1/2]

STATISTIC	(	NumAddrTaken	,
		"Number of local variables that have their address" " taken."
	)

STATISTIC() [2/2]

STATISTIC	(	NumFunProtected	,
		"Number of functions protected"
	)

Variable Documentation

DEBUG_TYPE

DEBUG_TYPE

Definition at line 76 of file StackProtector.cpp.

DisableCheckNoReturn

cl::opt< bool > DisableCheckNoReturn("disable-check-noreturn-call", cl::init(false), cl::Hidden) ( "disable-check-noreturn-call"  , cl::init(false)  , cl::Hidden    )

static

EnableSelectionDAGSP

cl::opt< bool > EnableSelectionDAGSP("enable-selectiondag-sp", cl::init(true), cl::Hidden) ( "enable-selectiondag-sp"  , cl::init(true)  , cl::Hidden    )

static

false

Insert stack false

Definition at line 77 of file StackProtector.cpp.

protectors

Insert stack protectors

Definition at line 77 of file StackProtector.cpp.