Merge pull request #63323 from meg-gupta/ptrauthaddrdiversified4

Changes to support imported structs with ptruath qualified field function pointers

Author: meg-gupta

lib/SIL/IR/TypeLowering.cpp

@@ -2292,7 +2292,7 @@ namespace {
       // Classify the type according to its stored properties.
       for (auto field : D->getStoredProperties()) {
         auto pointerAuthQual = field->getPointerAuthQualifier();
-        if (pointerAuthQual && pointerAuthQual.isAddressDiscriminated()) {
+        if (pointerAuthQual.isPresent()) {
           properties.setAddressOnly();
         }
         auto substFieldType =

lib/SIL/Verifier/SILVerifier.cpp

@@ -3286,6 +3286,10 @@ class SILVerifier : public SILVerifierBase<SILVerifier> {
                 EI->getForwardingOwnershipKind() == OwnershipKind::Guaranteed,
             "invalid forwarding ownership kind on tuple_extract instruction");
 
+    require(!EI->getStructDecl()->isNonTrivialPtrAuth(),
+            "Imported structs with ptrauth qualified fields should not be "
+            "promoted to a value");
+
     if (EI->getModule().getStage() != SILStage::Lowered) {
       SILType loweredFieldTy = operandTy.getFieldType(
           EI->getField(), F.getModule(), F.getTypeExpansionContext());
@@ -3333,6 +3337,14 @@ class SILVerifier : public SILVerifierBase<SILVerifier> {
     require(EI->getField()->getDeclContext() == sd,
             "struct_element_addr field is not a member of the struct");
 
+    if (EI->getStructDecl()->isNonTrivialPtrAuth()) {
+      for (auto *use : EI->getUses()) {
+        auto *bai = dyn_cast<BeginAccessInst>(use->getUser());
+        require(bai && bai->getEnforcement() == SILAccessEnforcement::Signed,
+                "Access to ptrauth qualified fields should be scoped with "
+                "begin_access [signed]/end_access");
+      }
+    }
     if (EI->getModule().getStage() != SILStage::Lowered) {
       SILType loweredFieldTy = operandTy.getFieldType(
           EI->getField(), F.getModule(), F.getTypeExpansionContext());

lib/SILOptimizer/Mandatory/AccessMarkerElimination.cpp

@@ -77,8 +77,10 @@ bool AccessMarkerElimination::shouldPreserveAccess(
   switch (enforcement) {
   case SILAccessEnforcement::Static:
   case SILAccessEnforcement::Unsafe:
-  case SILAccessEnforcement::Signed:
     return false;
+  // Signed access should be preserved until IRGen
+  case SILAccessEnforcement::Signed:
+    return true;
   case SILAccessEnforcement::Unknown:
   case SILAccessEnforcement::Dynamic:
     return Mod->getOptions().EnforceExclusivityDynamic;
@@ -100,7 +102,7 @@ AccessMarkerElimination::checkAndEliminateMarker(SILInstruction *inst) {
     if (beginAccess->isFromBuiltin())
       return inst->getIterator();
 
-    // Leave dynamic accesses in place, but delete all others.
+    // Leave dynamic and signed accesses in place, but delete all others.
     if (shouldPreserveAccess(beginAccess->getEnforcement()))
       return inst->getIterator();
 

test/SILGen/ptrauth_field_fptr_import.swift

@@ -48,6 +48,16 @@ func test_field_fn_ptr_swap() {
   ptr_to_secure_struct!.pointee.secure_func_ptr2 = t
 }
 
+// CHECK-LABEL: sil hidden [ossa] @$s25ptrauth_field_fptr_import05test_B12_fn_ptr_temps5Int32VyF :
+// CHECK:   [[STK:%.*]] = alloc_stack $SecureStruct, let, name "struct_with_signed_val"
+// CHECK:   [[FLD:%.*]] = struct_element_addr [[STK]] : $*SecureStruct, #SecureStruct.secure_func_ptr1
+// CHECK:   [[SIGNED:%.*]] = begin_access [read] [signed] [[FLD]] : $*Optional<@convention(c) () -> Int32>
+// CHECK-LABEL: } // end sil function '$s25ptrauth_field_fptr_import05test_B12_fn_ptr_temps5Int32VyF'
+func test_field_fn_ptr_temp() -> Int32 {
+  let struct_with_signed_val = ptr_to_secure_struct.pointee
+  return struct_with_signed_val.secure_func_ptr1()
+}
+
 // CHECK-LABEL: sil hidden [ossa] @$s25ptrauth_field_fptr_import024test_addr_discriminated_B8_fn_reads5Int32VyF :
 // CHECK: [[GLOB:%.*]] = global_addr @ptr_to_addr_discriminated_secure_struct : $*Optional<UnsafeMutablePointer<AddressDiscriminatedSecureStruct>>
 // CHECK: [[A1:%.*]] = begin_access [read] [dynamic] [[GLOB]] : $*Optional<UnsafeMutablePointer<AddressDiscriminatedSecureStruct>>