================
@@ -461,6 +463,162 @@ bool PreISelIntrinsicLowering::expandMemIntrinsicUses(
return Changed;
}
+namespace {
+
+enum class PointerEncoding {
+ Rotate,
+ PACCopyable,
+ PACNonCopyable,
+};
+
+bool expandProtectedFieldPtr(Function &Intr) {
+ Module &M = *Intr.getParent();
+
+ SmallPtrSet<GlobalValue *, 2> DSsToDeactivate;
+ SmallPtrSet<Instruction *, 2> LoadsStores;
+
+ Type *Int8Ty = Type::getInt8Ty(M.getContext());
+ Type *Int64Ty = Type::getInt64Ty(M.getContext());
+ PointerType *PtrTy = PointerType::get(M.getContext(), 0);
+
+ Function *SignIntr =
+ Intrinsic::getOrInsertDeclaration(&M, Intrinsic::ptrauth_sign, {});
+ Function *AuthIntr =
+ Intrinsic::getOrInsertDeclaration(&M, Intrinsic::ptrauth_auth, {});
+
+ auto *EmuFnTy = FunctionType::get(Int64Ty, {Int64Ty, Int64Ty}, false);
+ FunctionCallee EmuSignIntr = M.getOrInsertFunction("__emupac_pacda",
EmuFnTy);
+ FunctionCallee EmuAuthIntr = M.getOrInsertFunction("__emupac_autda",
EmuFnTy);
+
+ auto CreateSign = [&](IRBuilder<> &B, Value *Val, Value *Disc,
+ OperandBundleDef DSBundle) {
+ Function *F = B.GetInsertBlock()->getParent();
+ Attribute FSAttr = F->getFnAttribute("target-features");
+ if (FSAttr.isValid() && FSAttr.getValueAsString().contains("+pauth"))
+ return B.CreateCall(SignIntr, {Val, B.getInt32(2), Disc}, DSBundle);
+ return B.CreateCall(EmuSignIntr, {Val, Disc}, DSBundle);
+ };
+
+ auto CreateAuth = [&](IRBuilder<> &B, Value *Val, Value *Disc,
+ OperandBundleDef DSBundle) {
+ Function *F = B.GetInsertBlock()->getParent();
+ Attribute FSAttr = F->getFnAttribute("target-features");
+ if (FSAttr.isValid() && FSAttr.getValueAsString().contains("+pauth"))
+ return B.CreateCall(AuthIntr, {Val, B.getInt32(2), Disc}, DSBundle);
+ return B.CreateCall(EmuAuthIntr, {Val, Disc}, DSBundle);
+ };
+
+ auto GetDeactivationSymbol = [&](CallInst *Call) -> GlobalValue * {
+ if (auto Bundle =
+ Call->getOperandBundle(LLVMContext::OB_deactivation_symbol))
+ return cast<GlobalValue>(Bundle->Inputs[0]);
+ return nullptr;
+ };
+
+ for (User *U : Intr.users()) {
+ auto *Call = cast<CallInst>(U);
+ auto *DS = GetDeactivationSymbol(Call);
+
+ for (Use &U : Call->uses()) {
+ if (auto *LI = dyn_cast<LoadInst>(U.getUser())) {
+ if (isa<PointerType>(LI->getType())) {
+ LoadsStores.insert(LI);
+ continue;
+ }
+ }
+ if (auto *SI = dyn_cast<StoreInst>(U.getUser())) {
+ if (U.getOperandNo() == 1 &&
+ isa<PointerType>(SI->getValueOperand()->getType())) {
+ LoadsStores.insert(SI);
+ continue;
+ }
+ }
+ // Comparisons against null cannot be used to recover the original
+ // pointer so we allow them.
+ if (auto *CI = dyn_cast<ICmpInst>(U.getUser())) {
+ if (auto *Op = dyn_cast<Constant>(CI->getOperand(0)))
+ if (Op->isNullValue())
+ continue;
+ if (auto *Op = dyn_cast<Constant>(CI->getOperand(1)))
+ if (Op->isNullValue())
+ continue;
+ }
+ if (DS)
+ DSsToDeactivate.insert(DS);
+ }
+ }
+
+ for (Instruction *I : LoadsStores) {
+ auto *PointerOperand = isa<StoreInst>(I)
+ ? cast<StoreInst>(I)->getPointerOperand()
+ : cast<LoadInst>(I)->getPointerOperand();
+ auto *Call = cast<CallInst>(PointerOperand);
+
+ auto *Disc = Call->getArgOperand(1);
+ bool UseHWEncoding =
cast<ConstantInt>(Call->getArgOperand(2))->getZExtValue();
+
+ GlobalValue *DS = GetDeactivationSymbol(Call);
+ OperandBundleDef DSBundle("deactivation-symbol", DS);
+
+ if (auto *LI = dyn_cast<LoadInst>(I)) {
+ IRBuilder<> B(LI->getNextNode());
+ auto *LIInt = cast<Instruction>(B.CreatePtrToInt(LI, B.getInt64Ty()));
+ Value *Auth;
+ if (UseHWEncoding) {
+ Auth = CreateAuth(B, LIInt, Disc, DSBundle);
+ } else {
+ Auth = B.CreateAdd(LIInt, Disc);
+ Auth = B.CreateIntrinsic(
+ Auth->getType(), Intrinsic::fshr,
+ {Auth, Auth, ConstantInt::get(Auth->getType(), 16)});
+ }
+ LI->replaceAllUsesWith(B.CreateIntToPtr(Auth, B.getPtrTy()));
+ LIInt->setOperand(0, LI);
+ } else {
+ auto *SI = cast<StoreInst>(I);
+ IRBuilder<> B(SI);
+ auto *SIValInt =
+ B.CreatePtrToInt(SI->getValueOperand(), B.getInt64Ty());
+ Value *Sign;
+ if (UseHWEncoding) {
+ Sign = CreateSign(B, SIValInt, Disc, DSBundle);
+ } else {
+ Sign = B.CreateIntrinsic(
+ SIValInt->getType(), Intrinsic::fshl,
+ {SIValInt, SIValInt, ConstantInt::get(SIValInt->getType(), 16)});
+ Sign = B.CreateSub(Sign, Disc);
+ }
+ SI->setOperand(0, B.CreateIntToPtr(Sign, B.getPtrTy()));
+ }
+ }
+
+ for (User *U : llvm::make_early_inc_range(Intr.users())) {
+ auto *Call = cast<CallInst>(U);
+ auto *Pointer = Call->getArgOperand(0);
+
+ Call->replaceAllUsesWith(Pointer);
+ Call->eraseFromParent();
+ }
+
+ if (!DSsToDeactivate.empty()) {
+ Constant *Nop =
+ ConstantExpr::getIntToPtr(ConstantInt::get(Int64Ty, 0xd503201f),
PtrTy);
----------------
nikic wrote:
What's this magic constant?
https://github.com/llvm/llvm-project/pull/151647
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