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[stackprotector] Refactored ssp prologue creation code into its own helper function.

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No functionality change.

rdar://13935163

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186868 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Michael Gottesman 2013-07-22 20:44:11 +00:00
parent fdd16bb918
commit c03d5ec320
1 changed files with 41 additions and 35 deletions
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76
lib/CodeGen/StackProtector.cpp
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@ -265,6 +265,46 @@ bool StackProtector::RequiresStackProtector() {
return false;
}
/// Insert code into the entry block that stores the __stack_chk_guard
/// variable onto the stack:
///
/// entry:
/// StackGuardSlot = alloca i8*
/// StackGuard = load __stack_chk_guard
/// call void @llvm.stackprotect.create(StackGuard, StackGuardSlot)
///
static void CreatePrologue(Function *F, Module *M, ReturnInst *RI,
const TargetLoweringBase *TLI, const Triple &Trip,
AllocaInst *&AI, Value *&StackGuardVar) {
PointerType *PtrTy = Type::getInt8PtrTy(RI->getContext());
unsigned AddressSpace, Offset;
if (TLI->getStackCookieLocation(AddressSpace, Offset)) {
Constant *OffsetVal =
ConstantInt::get(Type::getInt32Ty(RI->getContext()), Offset);
StackGuardVar = ConstantExpr::getIntToPtr(OffsetVal,
PointerType::get(PtrTy,
AddressSpace));
} else if (Trip.getOS() == llvm::Triple::OpenBSD) {
StackGuardVar = M->getOrInsertGlobal("__guard_local", PtrTy);
cast<GlobalValue>(StackGuardVar)
->setVisibility(GlobalValue::HiddenVisibility);
} else {
StackGuardVar = M->getOrInsertGlobal("__stack_chk_guard", PtrTy);
}
BasicBlock &Entry = F->getEntryBlock();
Instruction *InsPt = &Entry.front();
AI = new AllocaInst(PtrTy, "StackGuardSlot", InsPt);
LoadInst *LI = new LoadInst(StackGuardVar, "StackGuard", false, InsPt);
Value *Args[] = { LI, AI };
CallInst::
Create(Intrinsic::getDeclaration(M, Intrinsic::stackprotector),
Args, "", InsPt);
}
/// InsertStackProtectors - Insert code into the prologue and epilogue of the
/// function.
///
@ -283,41 +323,7 @@ bool StackProtector::InsertStackProtectors() {
if (!RI) continue;
if (!FailBB) {
// Insert code into the entry block that stores the __stack_chk_guard
// variable onto the stack:
//
// entry:
// StackGuardSlot = alloca i8*
// StackGuard = load __stack_chk_guard
// call void @llvm.stackprotect.create(StackGuard, StackGuardSlot)
//
PointerType *PtrTy = Type::getInt8PtrTy(RI->getContext());
unsigned AddressSpace, Offset;
if (TLI->getStackCookieLocation(AddressSpace, Offset)) {
Constant *OffsetVal =
ConstantInt::get(Type::getInt32Ty(RI->getContext()), Offset);
StackGuardVar = ConstantExpr::getIntToPtr(OffsetVal,
PointerType::get(PtrTy, AddressSpace));
} else if (Trip.getOS() == llvm::Triple::OpenBSD) {
StackGuardVar = M->getOrInsertGlobal("__guard_local", PtrTy);
cast<GlobalValue>(StackGuardVar)
->setVisibility(GlobalValue::HiddenVisibility);
} else {
StackGuardVar = M->getOrInsertGlobal("__stack_chk_guard", PtrTy);
}
BasicBlock &Entry = F->getEntryBlock();
Instruction *InsPt = &Entry.front();
AI = new AllocaInst(PtrTy, "StackGuardSlot", InsPt);
LoadInst *LI = new LoadInst(StackGuardVar, "StackGuard", false, InsPt);
Value *Args[] = { LI, AI };
CallInst::
Create(Intrinsic::getDeclaration(M, Intrinsic::stackprotector),
Args, "", InsPt);
CreatePrologue(F, M, RI, TLI, Trip, AI, StackGuardVar);
// Create the basic block to jump to when the guard check fails.
FailBB = CreateFailBB();
}