BoundsChecking.cpp File Reference

#include "llvm/Transforms/Instrumentation/BoundsChecking.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Analysis/MemoryBuiltins.h"
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Analysis/TargetFolder.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InstIterator.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/Value.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include <cstdint>
#include <utility>

Go to the source code of this file.

Macros
#define	DEBUG_TYPE   "bounds-checking"

Typedefs
using	BuilderTy = IRBuilder< TargetFolder >

Functions
	STATISTIC (ChecksAdded, "Bounds checks added")
	STATISTIC (ChecksSkipped, "Bounds checks skipped")
	STATISTIC (ChecksUnable, "Bounds checks unable to add")
static Value *	getBoundsCheckCond (Value *Ptr, Value *InstVal, const DataLayout &DL, TargetLibraryInfo &TLI, ObjectSizeOffsetEvaluator &ObjSizeEval, BuilderTy &IRB, ScalarEvolution &SE)
	Gets the conditions under which memory accessing instructions will overflow.
template<typename GetTrapBBT >
static void	insertBoundsCheck (Value *Or, BuilderTy &IRB, GetTrapBBT GetTrapBB)
	Adds run-time bounds checks to memory accessing instructions.
static bool	addBoundsChecking (Function &F, TargetLibraryInfo &TLI, ScalarEvolution &SE)

Variables
static cl::opt< bool >	SingleTrapBB ("bounds-checking-single-trap", cl::desc("Use one trap block per function"))
static cl::opt< bool >	DebugTrapBB ("bounds-checking-unique-traps", cl::desc("Always use one trap per check"))

Macro Definition Documentation

DEBUG_TYPE

#define DEBUG_TYPE   "bounds-checking"

Definition at line 35 of file BoundsChecking.cpp.

Typedef Documentation

BuilderTy

using BuilderTy = IRBuilder<TargetFolder>

Definition at line 47 of file BoundsChecking.cpp.

Function Documentation

addBoundsChecking()

static bool addBoundsChecking ( Function &  F, TargetLibraryInfo &  TLI, ScalarEvolution &  SE  )

static

Definition at line 142 of file BoundsChecking.cpp.

References llvm::BasicBlock::Create(), DebugTrapBB, DL, llvm::SmallVectorBase< Size_T >::empty(), llvm::ObjectSizeOpts::EvalMode, F, getBoundsCheckCond(), llvm::Function::getContext(), llvm::Intrinsic::getDeclaration(), llvm::GlobalValue::getParent(), llvm::ilist_detail::node_parent_access< NodeTy, ParentTy >::getParent(), I, insertBoundsCheck(), instructions, llvm::Or, llvm::SmallVectorTemplateBase< T, bool >::push_back(), llvm::ObjectSizeOpts::RoundToAlign, llvm::Instruction::setDebugLoc(), llvm::CallBase::setDoesNotReturn(), llvm::CallBase::setDoesNotThrow(), SingleTrapBB, and llvm::Function::size().

Referenced by llvm::BoundsCheckingPass::run().

getBoundsCheckCond()

static Value * getBoundsCheckCond ( Value *  Ptr, Value *  InstVal, const DataLayout &  DL, TargetLibraryInfo &  TLI, ObjectSizeOffsetEvaluator &  ObjSizeEval, BuilderTy &  IRB, ScalarEvolution &  SE  )

static

Gets the conditions under which memory accessing instructions will overflow.

Ptr is the pointer that will be read/written, and InstVal is either the result from the load or the value being stored. It is used to determine the size of memory block that is touched.

Returns the condition under which the access will overflow.

Definition at line 56 of file BoundsChecking.cpp.

References llvm::SizeOffsetType< T, C >::bothKnown(), llvm::ObjectSizeOffsetEvaluator::compute(), llvm::IRBuilderBase::CreateICmpSLT(), llvm::IRBuilderBase::CreateICmpULT(), llvm::IRBuilderBase::CreateOr(), llvm::IRBuilderBase::CreateSub(), llvm::IRBuilderBase::CreateTypeSize(), llvm::dbgs(), DL, llvm::ConstantInt::getFalse(), llvm::ScalarEvolution::getSCEV(), llvm::Value::getType(), llvm::ScalarEvolution::getUnsignedRange(), llvm::ConstantInt::getValue(), LLVM_DEBUG, llvm::SizeOffsetType< T, C >::Offset, llvm::Offset, llvm::Or, Ptr, llvm::SizeOffsetType< T, C >::Size, Size, and llvm::APInt::slt().

Referenced by addBoundsChecking().

insertBoundsCheck()

template<typename GetTrapBBT >

static void insertBoundsCheck ( Value *  Or, BuilderTy &  IRB, GetTrapBBT  GetTrapBB  )

static

Adds run-time bounds checks to memory accessing instructions.

Or is the condition that should guard the trap.

GetTrapBB is a callable that returns the trap BB to use on failure.

Definition at line 114 of file BoundsChecking.cpp.

References llvm::CallingConv::C, llvm::BranchInst::Create(), llvm::Instruction::eraseFromParent(), llvm::IRBuilderBase::GetInsertPoint(), llvm::BasicBlock::getParent(), llvm::BasicBlock::getTerminator(), llvm::Or, and llvm::BasicBlock::splitBasicBlock().

Referenced by addBoundsChecking().

STATISTIC() [1/3]

STATISTIC	(	ChecksAdded	,
		"Bounds checks added"
	)

STATISTIC() [2/3]

STATISTIC	(	ChecksSkipped	,
		"Bounds checks skipped"
	)

STATISTIC() [3/3]

STATISTIC	(	ChecksUnable	,
		"Bounds checks unable to add"
	)

Variable Documentation

DebugTrapBB

cl::opt< bool > DebugTrapBB("bounds-checking-unique-traps", cl::desc("Always use one trap per check")) ( "bounds-checking-unique-traps"  , cl::desc("Always use one trap per check")    )

static

Referenced by addBoundsChecking().

SingleTrapBB

cl::opt< bool > SingleTrapBB("bounds-checking-single-trap", cl::desc("Use one trap block per function")) ( "bounds-checking-single-trap"  , cl::desc("Use one trap block per function")    )

static

Referenced by addBoundsChecking().