Add deactivation symbol operand to ConstantPtrAuth.

Deactivation symbol operands are supported in the code generator by
building on the previously added support for IRELATIVE relocations.

Reviewers: ojhunt, fmayer, ahmedbougacha, nikic, efriedma-quic

Reviewed By: fmayer

Pull Request: #133537

Author: pcc

clang/lib/CodeGen/CGPointerAuth.cpp

@@ -440,9 +440,10 @@ CodeGenModule::getConstantSignedPointer(llvm::Constant *Pointer, unsigned Key,
     IntegerDiscriminator = llvm::ConstantInt::get(Int64Ty, 0);
   }
 
-  return llvm::ConstantPtrAuth::get(Pointer,
-                                    llvm::ConstantInt::get(Int32Ty, Key),
-                                    IntegerDiscriminator, AddressDiscriminator);
+  return llvm::ConstantPtrAuth::get(
+      Pointer, llvm::ConstantInt::get(Int32Ty, Key), IntegerDiscriminator,
+      AddressDiscriminator,
+      /*DeactivationSymbol=*/llvm::Constant::getNullValue(DefaultPtrTy));
 }
 
 /// Does a given PointerAuthScheme require us to sign a value

llvm/docs/LangRef.rst

@@ -3234,6 +3234,8 @@ A "convergencectrl" operand bundle is only valid on a ``convergent`` operation.
 When present, the operand bundle must contain exactly one value of token type.
 See the :doc:`ConvergentOperations` document for details.
 
+.. _deactivationsymbol:
+
 Deactivation Symbol Operand Bundles
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
@@ -5300,7 +5302,7 @@ need to refer to the actual function body.
 Pointer Authentication Constants
 --------------------------------
 
-``ptrauth (ptr CST, i32 KEY[, i64 DISC[, ptr ADDRDISC]?]?)``
+``ptrauth (ptr CST, i32 KEY[, i64 DISC[, ptr ADDRDISC[, ptr DS]?]?]?)``
 
 A '``ptrauth``' constant represents a pointer with a cryptographic
 authentication signature embedded into some bits, as described in the
@@ -5329,6 +5331,11 @@ Otherwise, the expression is equivalent to:
     %tmp2 = call i64 @llvm.ptrauth.sign(i64 ptrtoint (ptr CST to i64), i32 KEY, i64 %tmp1)
     %val = inttoptr i64 %tmp2 to ptr
 
+If the deactivation symbol operand ``DS`` has a non-null value,
+the semantics are as if a :ref:`deactivation-symbol operand bundle
+<deactivationsymbol>` were added to the ``llvm.ptrauth.sign`` intrinsic
+calls above, with ``DS`` as the only operand.
+
 .. _constantexprs:
 
 Constant Expressions

llvm/include/llvm/Bitcode/LLVMBitCodes.h

@@ -437,6 +437,8 @@ enum ConstantsCodes {
   CST_CODE_CE_GEP_WITH_INRANGE = 31,  // [opty, flags, range, n x operands]
   CST_CODE_CE_GEP = 32,               // [opty, flags, n x operands]
   CST_CODE_PTRAUTH = 33,              // [ptr, key, disc, addrdisc]
+  CST_CODE_PTRAUTH2 = 34,             // [ptr, key, disc, addrdisc,
+                                      //  deactivation_symbol]
 };
 
 /// CastOpcodes - These are values used in the bitcode files to encode which

llvm/include/llvm/IR/Constants.h

@@ -1033,10 +1033,10 @@ class ConstantPtrAuth final : public Constant {
   friend struct ConstantPtrAuthKeyType;
   friend class Constant;
 
-  constexpr static IntrusiveOperandsAllocMarker AllocMarker{4};
+  constexpr static IntrusiveOperandsAllocMarker AllocMarker{5};
 
   ConstantPtrAuth(Constant *Ptr, ConstantInt *Key, ConstantInt *Disc,
-                  Constant *AddrDisc);
+                  Constant *AddrDisc, Constant *DeactivationSymbol);
 
   void *operator new(size_t s) { return User::operator new(s, AllocMarker); }
 
@@ -1046,7 +1046,8 @@ class ConstantPtrAuth final : public Constant {
 public:
   /// Return a pointer signed with the specified parameters.
   LLVM_ABI static ConstantPtrAuth *get(Constant *Ptr, ConstantInt *Key,
-                                       ConstantInt *Disc, Constant *AddrDisc);
+                                       ConstantInt *Disc, Constant *AddrDisc,
+                                       Constant *DeactivationSymbol);
 
   /// Produce a new ptrauth expression signing the given value using
   /// the same schema as is stored in one.
@@ -1078,6 +1079,10 @@ class ConstantPtrAuth final : public Constant {
     return !getAddrDiscriminator()->isNullValue();
   }
 
+  Constant *getDeactivationSymbol() const {
+    return cast<Constant>(Op<4>().get());
+  }
+
   /// A constant value for the address discriminator which has special
   /// significance to ctors/dtors lowering. Regular address discrimination can't
   /// be applied for them since uses of llvm.global_{c|d}tors are disallowed
@@ -1106,7 +1111,7 @@ class ConstantPtrAuth final : public Constant {
 
 template <>
 struct OperandTraits<ConstantPtrAuth>
-    : public FixedNumOperandTraits<ConstantPtrAuth, 4> {};
+    : public FixedNumOperandTraits<ConstantPtrAuth, 5> {};
 
 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(ConstantPtrAuth, Constant)
 

llvm/include/llvm/SandboxIR/Constant.h

@@ -1363,7 +1363,8 @@ class ConstantPtrAuth final : public Constant {
 public:
   /// Return a pointer signed with the specified parameters.
   LLVM_ABI static ConstantPtrAuth *get(Constant *Ptr, ConstantInt *Key,
-                                       ConstantInt *Disc, Constant *AddrDisc);
+                                       ConstantInt *Disc, Constant *AddrDisc,
+                                       Constant *DeactivationSymbol);
   /// The pointer that is signed in this ptrauth signed pointer.
   LLVM_ABI Constant *getPointer() const;
 
@@ -1378,6 +1379,8 @@ class ConstantPtrAuth final : public Constant {
   /// the only global-initializer user of the ptrauth signed pointer.
   LLVM_ABI Constant *getAddrDiscriminator() const;
 
+  Constant *getDeactivationSymbol() const;
+
   /// Whether there is any non-null address discriminator.
   bool hasAddressDiscriminator() const {
     return cast<llvm::ConstantPtrAuth>(Val)->hasAddressDiscriminator();

llvm/lib/AsmParser/LLParser.cpp

@@ -4250,11 +4250,13 @@ bool LLParser::parseValID(ValID &ID, PerFunctionState *PFS, Type *ExpectedTy) {
   }
   case lltok::kw_ptrauth: {
     // ValID ::= 'ptrauth' '(' ptr @foo ',' i32 <key>
-    //                         (',' i64 <disc> (',' ptr addrdisc)? )? ')'
+    //                         (',' i64 <disc> (',' ptr addrdisc (',' ptr ds)?
+    //                         )? )? ')'
     Lex.Lex();
 
     Constant *Ptr, *Key;
-    Constant *Disc = nullptr, *AddrDisc = nullptr;
+    Constant *Disc = nullptr, *AddrDisc = nullptr,
+             *DeactivationSymbol = nullptr;
 
     if (parseToken(lltok::lparen,
                    "expected '(' in constant ptrauth expression") ||
@@ -4263,11 +4265,14 @@ bool LLParser::parseValID(ValID &ID, PerFunctionState *PFS, Type *ExpectedTy) {
                    "expected comma in constant ptrauth expression") ||
         parseGlobalTypeAndValue(Key))
       return true;
-    // If present, parse the optional disc/addrdisc.
-    if (EatIfPresent(lltok::comma))
-      if (parseGlobalTypeAndValue(Disc) ||
-          (EatIfPresent(lltok::comma) && parseGlobalTypeAndValue(AddrDisc)))
-        return true;
+    // If present, parse the optional disc/addrdisc/ds.
+    if (EatIfPresent(lltok::comma) && parseGlobalTypeAndValue(Disc))
+      return true;
+    if (EatIfPresent(lltok::comma) && parseGlobalTypeAndValue(AddrDisc))
+      return true;
+    if (EatIfPresent(lltok::comma) &&
+        parseGlobalTypeAndValue(DeactivationSymbol))
+      return true;
     if (parseToken(lltok::rparen,
                    "expected ')' in constant ptrauth expression"))
       return true;
@@ -4298,7 +4303,15 @@ bool LLParser::parseValID(ValID &ID, PerFunctionState *PFS, Type *ExpectedTy) {
       AddrDisc = ConstantPointerNull::get(PointerType::get(Context, 0));
     }
 
-    ID.ConstantVal = ConstantPtrAuth::get(Ptr, KeyC, DiscC, AddrDisc);
+    if (!DeactivationSymbol)
+      DeactivationSymbol =
+          ConstantPointerNull::get(PointerType::get(Context, 0));
+    if (!DeactivationSymbol->getType()->isPointerTy())
+      return error(ID.Loc,
+                   "constant ptrauth deactivation symbol must be a pointer");
+
+    ID.ConstantVal =
+        ConstantPtrAuth::get(Ptr, KeyC, DiscC, AddrDisc, DeactivationSymbol);
     ID.Kind = ValID::t_Constant;
     return false;
   }

llvm/lib/Bitcode/Reader/BitcodeReader.cpp

@@ -1609,7 +1609,16 @@ Expected<Value *> BitcodeReader::materializeValue(unsigned StartValID,
           if (!Disc)
             return error("ptrauth disc operand must be ConstantInt");
 
-          C = ConstantPtrAuth::get(ConstOps[0], Key, Disc, ConstOps[3]);
+          Constant *DeactivationSymbol =
+              ConstOps.size() > 4 ? ConstOps[4]
+                                  : ConstantPointerNull::get(cast<PointerType>(
+                                        ConstOps[3]->getType()));
+          if (!DeactivationSymbol->getType()->isPointerTy())
+            return error(
+                "ptrauth deactivation symbol operand must be a pointer");
+
+          C = ConstantPtrAuth::get(ConstOps[0], Key, Disc, ConstOps[3],
+                                   DeactivationSymbol);
           break;
         }
         case BitcodeConstant::NoCFIOpcode: {
@@ -3813,6 +3822,16 @@ Error BitcodeReader::parseConstants() {
                                    (unsigned)Record[2], (unsigned)Record[3]});
       break;
     }
+    case bitc::CST_CODE_PTRAUTH2: {
+      if (Record.size() < 5)
+        return error("Invalid ptrauth record");
+      // Ptr, Key, Disc, AddrDisc, DeactivationSymbol
+      V = BitcodeConstant::create(
+          Alloc, CurTy, BitcodeConstant::ConstantPtrAuthOpcode,
+          {(unsigned)Record[0], (unsigned)Record[1], (unsigned)Record[2],
+           (unsigned)Record[3], (unsigned)Record[4]});
+      break;
+    }
     }
 
     assert(V->getType() == getTypeByID(CurTyID) && "Incorrect result type ID");

llvm/lib/Bitcode/Writer/BitcodeWriter.cpp

@@ -3030,11 +3030,12 @@ void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
       Record.push_back(VE.getTypeID(NC->getGlobalValue()->getType()));
       Record.push_back(VE.getValueID(NC->getGlobalValue()));
     } else if (const auto *CPA = dyn_cast<ConstantPtrAuth>(C)) {
-      Code = bitc::CST_CODE_PTRAUTH;
+      Code = bitc::CST_CODE_PTRAUTH2;
       Record.push_back(VE.getValueID(CPA->getPointer()));
       Record.push_back(VE.getValueID(CPA->getKey()));
       Record.push_back(VE.getValueID(CPA->getDiscriminator()));
       Record.push_back(VE.getValueID(CPA->getAddrDiscriminator()));
+      Record.push_back(VE.getValueID(CPA->getDeactivationSymbol()));
     } else {
 #ifndef NDEBUG
       C->dump();

llvm/lib/IR/AsmWriter.cpp

@@ -1674,12 +1674,14 @@ static void writeConstantInternal(raw_ostream &Out, const Constant *CV,
   if (const auto *CPA = dyn_cast<ConstantPtrAuth>(CV)) {
     Out << "ptrauth (";
 
-    // ptrauth (ptr CST, i32 KEY[, i64 DISC[, ptr ADDRDISC]?]?)
+    // ptrauth (ptr CST, i32 KEY[, i64 DISC[, ptr ADDRDISC[, ptr DS]?]?]?)
     unsigned NumOpsToWrite = 2;
     if (!CPA->getOperand(2)->isNullValue())
       NumOpsToWrite = 3;
     if (!CPA->getOperand(3)->isNullValue())
       NumOpsToWrite = 4;
+    if (!CPA->getOperand(4)->isNullValue())
+      NumOpsToWrite = 5;
 
     ListSeparator LS;
     for (unsigned i = 0, e = NumOpsToWrite; i != e; ++i) {

llvm/lib/IR/Constants.cpp

@@ -2081,28 +2081,33 @@ Value *NoCFIValue::handleOperandChangeImpl(Value *From, Value *To) {
 //
 
 ConstantPtrAuth *ConstantPtrAuth::get(Constant *Ptr, ConstantInt *Key,
-                                      ConstantInt *Disc, Constant *AddrDisc) {
-  Constant *ArgVec[] = {Ptr, Key, Disc, AddrDisc};
+                                      ConstantInt *Disc, Constant *AddrDisc,
+                                      Constant *DeactivationSymbol) {
+  Constant *ArgVec[] = {Ptr, Key, Disc, AddrDisc, DeactivationSymbol};
   ConstantPtrAuthKeyType MapKey(ArgVec);
   LLVMContextImpl *pImpl = Ptr->getContext().pImpl;
   return pImpl->ConstantPtrAuths.getOrCreate(Ptr->getType(), MapKey);
 }
 
 ConstantPtrAuth *ConstantPtrAuth::getWithSameSchema(Constant *Pointer) const {
-  return get(Pointer, getKey(), getDiscriminator(), getAddrDiscriminator());
+  return get(Pointer, getKey(), getDiscriminator(), getAddrDiscriminator(),
+             getDeactivationSymbol());
 }
 
 ConstantPtrAuth::ConstantPtrAuth(Constant *Ptr, ConstantInt *Key,
-                                 ConstantInt *Disc, Constant *AddrDisc)
+                                 ConstantInt *Disc, Constant *AddrDisc,
+                                 Constant *DeactivationSymbol)
     : Constant(Ptr->getType(), Value::ConstantPtrAuthVal, AllocMarker) {
   assert(Ptr->getType()->isPointerTy());
   assert(Key->getBitWidth() == 32);
   assert(Disc->getBitWidth() == 64);
   assert(AddrDisc->getType()->isPointerTy());
+  assert(DeactivationSymbol->getType()->isPointerTy());
   setOperand(0, Ptr);
   setOperand(1, Key);
   setOperand(2, Disc);
   setOperand(3, AddrDisc);
+  setOperand(4, DeactivationSymbol);
 }
 
 /// Remove the constant from the constant table.
@@ -2150,6 +2155,11 @@ bool ConstantPtrAuth::hasSpecialAddressDiscriminator(uint64_t Value) const {
 bool ConstantPtrAuth::isKnownCompatibleWith(const Value *Key,
                                             const Value *Discriminator,
                                             const DataLayout &DL) const {
+  // This function may only be validly called to analyze a ptrauth operation
+  // with no deactivation symbol, so if we have one it isn't compatible.
+  if (!getDeactivationSymbol()->isNullValue())
+    return false;
+
   // If the keys are different, there's no chance for this to be compatible.
   if (getKey() != Key)
     return false;