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[stackprotector] Refactor the StackProtector pass from a single .cpp file into StackProtector.h and StackProtector.cpp.

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No functionality change.  Future patches will add analysis which will be used
in other passes (PEI, StackSlot).  The end goal is to support ssp-strong stack
layout rules.

WIP.

Differential Revision: http://llvm-reviews.chandlerc.com/D1521


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191570 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Josh Magee 2013-09-27 21:58:43 +00:00
parent 29552222c2
commit 18ebd48960
2 changed files with 98 additions and 70 deletions
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97
include/llvm/CodeGen/StackProtector.h Normal file
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@ -0,0 +1,97 @@
//===-- StackProtector.h - Stack Protector Insertion ----------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This pass inserts stack protectors into functions which need them. A variable
// with a random value in it is stored onto the stack before the local variables
// are allocated. Upon exiting the block, the stored value is checked. If it's
// changed, then there was some sort of violation and the program aborts.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_STACKPROTECTOR_H
#define LLVM_CODEGEN_STACKPROTECTOR_H
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/Triple.h"
#include "llvm/Pass.h"
#include "llvm/Target/TargetLowering.h"
namespace llvm {
class DominatorTree;
class Function;
class Module;
class PHINode;
class StackProtector : public FunctionPass {
const TargetMachine *TM;
/// TLI - Keep a pointer of a TargetLowering to consult for determining
/// target type sizes.
const TargetLoweringBase *TLI;
const Triple Trip;
Function *F;
Module *M;
DominatorTree *DT;
/// \brief The minimum size of buffers that will receive stack smashing
/// protection when -fstack-protection is used.
unsigned SSPBufferSize;
/// VisitedPHIs - The set of PHI nodes visited when determining
/// if a variable's reference has been taken. This set
/// is maintained to ensure we don't visit the same PHI node multiple
/// times.
SmallPtrSet<const PHINode*, 16> VisitedPHIs;
/// InsertStackProtectors - Insert code into the prologue and epilogue of
/// the function.
///
/// - The prologue code loads and stores the stack guard onto the stack.
/// - The epilogue checks the value stored in the prologue against the
/// original value. It calls __stack_chk_fail if they differ.
bool InsertStackProtectors();
/// CreateFailBB - Create a basic block to jump to when the stack protector
/// check fails.
BasicBlock *CreateFailBB();
/// ContainsProtectableArray - Check whether the type either is an array or
/// contains an array of sufficient size so that we need stack protectors
/// for it.
bool ContainsProtectableArray(Type *Ty, bool Strong = false,
bool InStruct = false) const;
/// \brief Check whether a stack allocation has its address taken.
bool HasAddressTaken(const Instruction *AI);
/// RequiresStackProtector - Check whether or not this function needs a
/// stack protector based upon the stack protector level.
bool RequiresStackProtector();
public:
static char ID; // Pass identification, replacement for typeid.
StackProtector() : FunctionPass(ID), TM(0), TLI(0), SSPBufferSize(0) {
initializeStackProtectorPass(*PassRegistry::getPassRegistry());
}
StackProtector(const TargetMachine *TM)
: FunctionPass(ID), TM(TM), TLI(0), Trip(TM->getTargetTriple()),
SSPBufferSize(8) {
initializeStackProtectorPass(*PassRegistry::getPassRegistry());
}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addPreserved<DominatorTree>();
}
virtual bool runOnFunction(Function &Fn);
};
} // end namespace llvm
#endif // LLVM_CODEGEN_STACKPROTECTOR_H

71
lib/CodeGen/StackProtector.cpp
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@ -15,11 +15,11 @@
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "stack-protector"
#include "llvm/CodeGen/StackProtector.h"
#include "llvm/CodeGen/Analysis.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/Triple.h"
#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/Attributes.h"
@ -34,9 +34,7 @@
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/Module.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Target/TargetLowering.h"
#include <cstdlib>
using namespace llvm;
@ -48,73 +46,6 @@ static cl::opt<bool>
EnableSelectionDAGSP("enable-selectiondag-sp", cl::init(true),
cl::Hidden);
namespace {
class StackProtector : public FunctionPass {
const TargetMachine *TM;
/// TLI - Keep a pointer of a TargetLowering to consult for determining
/// target type sizes.
const TargetLoweringBase *TLI;
const Triple Trip;
Function *F;
Module *M;
DominatorTree *DT;
/// \brief The minimum size of buffers that will receive stack smashing
/// protection when -fstack-protection is used.
unsigned SSPBufferSize;
/// VisitedPHIs - The set of PHI nodes visited when determining
/// if a variable's reference has been taken. This set
/// is maintained to ensure we don't visit the same PHI node multiple
/// times.
SmallPtrSet<const PHINode*, 16> VisitedPHIs;
/// InsertStackProtectors - Insert code into the prologue and epilogue of
/// the function.
///
/// - The prologue code loads and stores the stack guard onto the stack.
/// - The epilogue checks the value stored in the prologue against the
/// original value. It calls __stack_chk_fail if they differ.
bool InsertStackProtectors();
/// CreateFailBB - Create a basic block to jump to when the stack protector
/// check fails.
BasicBlock *CreateFailBB();
/// ContainsProtectableArray - Check whether the type either is an array or
/// contains an array of sufficient size so that we need stack protectors
/// for it.
bool ContainsProtectableArray(Type *Ty, bool Strong = false,
bool InStruct = false) const;
/// \brief Check whether a stack allocation has its address taken.
bool HasAddressTaken(const Instruction *AI);
/// RequiresStackProtector - Check whether or not this function needs a
/// stack protector based upon the stack protector level.
bool RequiresStackProtector();
public:
static char ID; // Pass identification, replacement for typeid.
StackProtector() : FunctionPass(ID), TM(0), TLI(0), SSPBufferSize(0) {
initializeStackProtectorPass(*PassRegistry::getPassRegistry());
}
StackProtector(const TargetMachine *TM)
: FunctionPass(ID), TM(TM), TLI(0), Trip(TM->getTargetTriple()),
SSPBufferSize(8) {
initializeStackProtectorPass(*PassRegistry::getPassRegistry());
}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addPreserved<DominatorTree>();
}
virtual bool runOnFunction(Function &Fn);
};
} // end anonymous namespace
char StackProtector::ID = 0;
INITIALIZE_PASS(StackProtector, "stack-protector",
"Insert stack protectors", false, false)