[ownership] Update devirtualization utilities for ownership.

I discovered this due to the mandatory inliner doing devirtualization. I ported
all of the relevant SIL tests to increase code coverage of this code when
ownership is enabled.

Author: gottesmm

include/swift/SIL/InstructionUtils.h

@@ -44,6 +44,10 @@ SILValue stripCasts(SILValue V);
 /// mark_dependence) from the current SILValue.
 SILValue stripCastsWithoutMarkDependence(SILValue V);
 
+/// Return the underlying SILValue after stripping off all copy_value and
+/// begin_borrow instructions.
+SILValue stripOwnershipInsts(SILValue v);
+
 /// Return the underlying SILValue after stripping off all upcasts from the
 /// current SILValue.
 SILValue stripUpCasts(SILValue V);

include/swift/SIL/SILBuilder.h

@@ -2179,6 +2179,13 @@ class SILBuilderWithScope : public SILBuilder {
     : SILBuilder(I, I->getDebugScope(), C)
   {}
 
+  /// Build instructions before the given insertion point, inheriting the debug
+  /// location and using the context from the passed in builder.
+  ///
+  /// Clients should prefer this constructor.
+  SILBuilderWithScope(SILInstruction *I, SILBuilder &B)
+      : SILBuilder(I, I->getDebugScope(), B.getBuilderContext()) {}
+
   explicit SILBuilderWithScope(
       SILInstruction *I,
       SmallVectorImpl<SILInstruction *> *InsertedInstrs = nullptr)

lib/SIL/InstructionUtils.cpp

@@ -22,15 +22,30 @@
 
 using namespace swift;
 
+SILValue swift::stripOwnershipInsts(SILValue v) {
+  while (true) {
+    switch (v->getKind()) {
+    default:
+      return v;
+    case ValueKind::CopyValueInst:
+    case ValueKind::BeginBorrowInst:
+      v = cast<SingleValueInstruction>(v)->getOperand(0);
+    }
+  }
+}
+
 /// Strip off casts/indexing insts/address projections from V until there is
 /// nothing left to strip.
 /// FIXME: Why don't we strip projections after stripping indexes?
-SILValue swift::getUnderlyingObject(SILValue V) {
+SILValue swift::getUnderlyingObject(SILValue v) {
   while (true) {
-    SILValue V2 = stripIndexingInsts(stripAddressProjections(stripCasts(V)));
-    if (V2 == V)
-      return V2;
-    V = V2;
+    SILValue v2 = stripCasts(v);
+    v2 = stripAddressProjections(v2);
+    v2 = stripIndexingInsts(v2);
+    v2 = stripOwnershipInsts(v2);
+    if (v2 == v)
+      return v2;
+    v = v2;
   }
 }
 
@@ -56,12 +71,15 @@ SILValue swift::getUnderlyingAddressRoot(SILValue V) {
 }
 
 
-SILValue swift::getUnderlyingObjectStopAtMarkDependence(SILValue V) {
+SILValue swift::getUnderlyingObjectStopAtMarkDependence(SILValue v) {
   while (true) {
-    SILValue V2 = stripIndexingInsts(stripAddressProjections(stripCastsWithoutMarkDependence(V)));
-    if (V2 == V)
-      return V2;
-    V = V2;
+    SILValue v2 = stripCastsWithoutMarkDependence(v);
+    v2 = stripAddressProjections(v2);
+    v2 = stripIndexingInsts(v2);
+    v2 = stripOwnershipInsts(v2);
+    if (v2 == v)
+      return v2;
+    v = v2;
   }
 }
 
@@ -138,47 +156,68 @@ SILValue swift::stripCastsWithoutMarkDependence(SILValue V) {
   }
 }
 
-SILValue swift::stripCasts(SILValue V) {
+SILValue swift::stripCasts(SILValue v) {
   while (true) {
-    V = stripSinglePredecessorArgs(V);
+    v = stripSinglePredecessorArgs(v);
 
-    auto K = V->getKind();
-    if (isRCIdentityPreservingCast(K)
-        || K == ValueKind::UncheckedTrivialBitCastInst
-        || K == ValueKind::MarkDependenceInst) {
-      V = cast<SingleValueInstruction>(V)->getOperand(0);
+    auto k = v->getKind();
+    if (isRCIdentityPreservingCast(k)
+        || k == ValueKind::UncheckedTrivialBitCastInst
+        || k == ValueKind::MarkDependenceInst) {
+      v = cast<SingleValueInstruction>(v)->getOperand(0);
       continue;
     }
-    
-    return V;
+
+    SILValue v2 = stripOwnershipInsts(v);
+    if (v2 != v) {
+      v = v2;
+      continue;
+    }
+
+    return v;
   }
 }
 
-SILValue swift::stripUpCasts(SILValue V) {
-  assert(V->getType().isClassOrClassMetatype() &&
+SILValue swift::stripUpCasts(SILValue v) {
+  assert(v->getType().isClassOrClassMetatype() &&
          "Expected class or class metatype!");
 
-  V = stripSinglePredecessorArgs(V);
-  
-  while (auto upcast = dyn_cast<UpcastInst>(V))
-    V = stripSinglePredecessorArgs(upcast->getOperand());
+  v = stripSinglePredecessorArgs(v);
 
-  return V;
+  while (true) {
+    if (auto *ui = dyn_cast<UpcastInst>(v)) {
+      v = ui->getOperand();
+      continue;
+    }
+
+    SILValue v2 = stripSinglePredecessorArgs(v);
+    v2 = stripOwnershipInsts(v2);
+    if (v2 == v) {
+      return v2;
+    }
+    v = v2;
+  }
 }
 
-SILValue swift::stripClassCasts(SILValue V) {
+SILValue swift::stripClassCasts(SILValue v) {
   while (true) {
-    if (auto *UI = dyn_cast<UpcastInst>(V)) {
-      V = UI->getOperand();
+    if (auto *ui = dyn_cast<UpcastInst>(v)) {
+      v = ui->getOperand();
       continue;
     }
 
-    if (auto *UCCI = dyn_cast<UnconditionalCheckedCastInst>(V)) {
-      V = UCCI->getOperand();
+    if (auto *ucci = dyn_cast<UnconditionalCheckedCastInst>(v)) {
+      v = ucci->getOperand();
       continue;
     }
-    
-    return V;
+
+    SILValue v2 = stripOwnershipInsts(v);
+    if (v2 != v) {
+      v = v2;
+      continue;
+    }
+
+    return v;
   }
 }