DI: Add an assertion tracking stores to the 'self' box

Author: slavapestov

lib/SILOptimizer/Mandatory/DIMemoryUseCollectorOwnership.cpp

@@ -1059,6 +1059,10 @@ void ElementUseCollector::collectClassSelfUses() {
     return;
   }
 
+  // The number of stores of the initial 'self' argument into the self box
+  // that we saw.
+  unsigned StoresOfArgumentToSelf = 0;
+
   // Okay, given that we have a proper setup, we walk the use chains of the self
   // box to find any accesses to it. The possible uses are one of:
   //
@@ -1076,9 +1080,12 @@ void ElementUseCollector::collectClassSelfUses() {
       if (Op->getOperandNumber() == 1) {
         // The initial store of 'self' into the box at the start of the
         // function. Ignore it.
-        if (auto *Arg = dyn_cast<SILArgument>(SI->getSrc()))
-          if (Arg->getParent() == MUI->getParent())
+        if (auto *Arg = dyn_cast<SILArgument>(SI->getSrc())) {
+          if (Arg->getParent() == MUI->getParent()) {
+            StoresOfArgumentToSelf++;
             continue;
+          }
+        }
 
         // A store of a load from the box is ignored.
         // FIXME: SILGen should not emit these.
@@ -1121,6 +1128,9 @@ void ElementUseCollector::collectClassSelfUses() {
     // and super.init must be called.
     trackUse(DIMemoryUse(User, DIUseKind::Load, 0, TheMemory.NumElements));
   }
+
+  assert(StoresOfArgumentToSelf == 1 &&
+         "The 'self' argument should have been stored into the box exactly once");
 }
 
 static bool isSuperInitUse(SILInstruction *User) {
@@ -1430,6 +1440,10 @@ void DelegatingInitElementUseCollector::collectClassInitSelfUses() {
   assert(TheMemory.NumElements == 1 && "delegating inits only have 1 bit");
   auto *MUI = cast<MarkUninitializedInst>(TheMemory.MemoryInst);
 
+  // The number of stores of the initial 'self' argument into the self box
+  // that we saw.
+  unsigned StoresOfArgumentToSelf = 0;
+
   // We walk the use chains of the self MUI to find any accesses to it.  The
   // possible uses are:
   //   1) The initialization store.
@@ -1451,9 +1465,12 @@ void DelegatingInitElementUseCollector::collectClassInitSelfUses() {
       if (Op->getOperandNumber() == 1) {
         // The initial store of 'self' into the box at the start of the
         // function. Ignore it.
-        if (auto *Arg = dyn_cast<SILArgument>(SI->getSrc()))
-          if (Arg->getParent() == MUI->getParent())
+        if (auto *Arg = dyn_cast<SILArgument>(SI->getSrc())) {
+          if (Arg->getParent() == MUI->getParent()) {
+            StoresOfArgumentToSelf++;
             continue;
+          }
+        }
 
         // A store of a load from the box is ignored.
         // FIXME: SILGen should not emit these.
@@ -1524,6 +1541,14 @@ void DelegatingInitElementUseCollector::collectClassInitSelfUses() {
     UseInfo.trackUse(DIMemoryUse(User, DIUseKind::Escape, 0, 1));
   }
 
+  if (TheMemory.isClassInitSelf()) {
+    assert(StoresOfArgumentToSelf == 1 &&
+           "The 'self' argument should have been stored into the box exactly once");
+  } else {
+    assert(StoresOfArgumentToSelf == 0 &&
+           "Initializing constructor for class-constrained protocol extension?");
+  }
+
   // The MUI must be used on an alloc_box or alloc_stack instruction. If we have
   // an alloc_stack, there is nothing further to do.
   if (isa<AllocStackInst>(MUI->getOperand()))

test/SILOptimizer/definite_init_markuninitialized_delegatingself.sil

@@ -203,13 +203,14 @@ class MyClass3 {
 sil @selfinit_myclass3 : $@convention(thin) (@owned MyClass3) -> @owned MyClass3
 
 // CHECK-LABEL: sil hidden @test_conditional_destroy_class_delegating_init
-sil hidden @test_conditional_destroy_class_delegating_init : $@convention(thin) (Builtin.Int1) -> () {
-bb0(%0 : @trivial $Builtin.Int1):
+sil hidden @test_conditional_destroy_class_delegating_init : $@convention(thin) (Builtin.Int1, @owned MyClass3) -> () {
+bb0(%0 : @trivial $Builtin.Int1, %1 : @owned $MyClass3):
 // CHECK:  [[CONTROL:%[0-9]+]] = alloc_stack $Builtin.Int2
 // CHECK-NEXT: [[SELF_BOX:%[0-9]+]] = alloc_stack $MyClass3
 
   %2 = alloc_stack $MyClass3
   %3 = mark_uninitialized [delegatingself] %2 : $*MyClass3
+  store %1 to [init] %3 : $*MyClass3
 
 // CHECK:  cond_br %0, [[SUCCESS:bb[0-9]+]], [[EXIT:bb[0-9]+]]
   cond_br %0, bb1, bb2