Update store_borrow verification in MemoryLifetimeVerifier

- Ensure there are no double end_borrows
- Ensure there are no end_borrows after dealloc_stack of the dest

Author: meg-gupta

lib/SIL/Verifier/MemoryLifetimeVerifier.cpp

@@ -377,6 +377,13 @@ void MemoryLifetimeVerifier::initDataflowInBlock(SILBasicBlock *block,
         }
         break;
       }
+      case SILInstructionKind::EndBorrowInst: {
+        auto *ebi = cast<EndBorrowInst>(&I);
+        if (auto *sbi = dyn_cast<StoreBorrowInst>(ebi->getOperand())) {
+          killBits(state, sbi->getDest());
+        }
+        break;
+      }
       case SILInstructionKind::DestroyAddrInst:
       case SILInstructionKind::DeallocStackInst:
         killBits(state, I.getOperand(0));
@@ -696,8 +703,13 @@ void MemoryLifetimeVerifier::checkBlock(SILBasicBlock *block, Bits &bits) {
         break;
       }
       case SILInstructionKind::EndBorrowInst: {
-        if (SILValue orig = cast<EndBorrowInst>(&I)->getSingleOriginalValue())
-          requireBitsSet(bits, orig, &I);
+        auto *ebi = cast<EndBorrowInst>(&I);
+        if (auto *sbi = dyn_cast<StoreBorrowInst>(ebi->getOperand())) {
+          requireBitsSet(bits, sbi->getDest(), &I);
+          locations.clearBits(bits, sbi->getDest());
+        } else if (auto *lbi = dyn_cast<LoadBorrowInst>(ebi->getOperand())) {
+          requireBitsSet(bits, lbi->getOperand(), &I);
+        }
         break;
       }
       case SILInstructionKind::UncheckedRefCastAddrInst:
@@ -779,11 +791,7 @@ void MemoryLifetimeVerifier::checkBlock(SILBasicBlock *block, Bits &bits) {
       }
       case SILInstructionKind::DeallocStackInst: {
         SILValue opVal = cast<DeallocStackInst>(&I)->getOperand();
-        if (isStoreBorrowLocation(opVal)) {
-          requireBitsSet(bits, opVal, &I);
-        } else {
-          requireBitsClear(bits & nonTrivialLocations, opVal, &I);
-        }
+        requireBitsClear(bits & nonTrivialLocations, opVal, &I);
         // Needed to clear any bits of trivial locations (which are not required
         // to be zero).
         locations.clearBits(bits, opVal);

test/SIL/memory_lifetime_failures.sil

@@ -373,6 +373,17 @@ bb0(%0 :  @guaranteed $Optional<T>):
   return %res : $()
 }
 
+// CHECK: SIL memory lifetime failure in @test_store_borrow_addr_after_dealloc: memory is initialized, but shouldn't be
+sil [ossa] @test_store_borrow_addr_after_dealloc : $@convention(thin) (@guaranteed Optional<T>) -> () {
+bb0(%0 :  @guaranteed $Optional<T>):
+  %s = alloc_stack $Optional<T>
+  %sb = store_borrow %0 to %s : $*Optional<T>
+  dealloc_stack %s : $*Optional<T>
+  end_borrow %sb : $*Optional<T>
+  %res = tuple ()
+  return %res : $()
+}
+
 // CHECK: SIL memory lifetime failure in @test_cast_br_take_always: memory is not initialized, but should be
 sil [ossa] @test_cast_br_take_always : $@convention(thin) <U, V> (@in U) -> () {
 bb0(%0 : $*U):