---

yaml
---
r: 343743
b: refs/heads/master-rebranch
c: 3d0b12e
h: refs/heads/master
i:
  343741: 813f4b6
  343739: 2b80fed
  343735: 96cbea2
  343727: 0380443
  343711: 1432671
  343679: 7aebf3b

Author: eeckstein

[refs]

@@ -1455,7 +1455,7 @@ refs/tags/swift-DEVELOPMENT-SNAPSHOT-2019-08-02-a: ddd2b2976aa9bfde5f20fe37f6bd2
 refs/tags/swift-DEVELOPMENT-SNAPSHOT-2019-08-03-a: 171cc166f2abeb5ca2a4003700a8a78a108bd300
 refs/heads/benlangmuir-patch-1: baaebaf39d52f3bf36710d4fe40cf212e996b212
 refs/heads/i-do-redeclare: 8c4e6d5de5c1e3f0a2cedccf319df713ea22c48e
-refs/heads/master-rebranch: 33011bb6c9d4c5721669b8f44159fb8bea10c5a2
+refs/heads/master-rebranch: 3d0b12e7bc07e518d2bb9e13ae6460c46fd2877c
 refs/heads/rdar-53901732: 9bd06af3284e18a109cdbf9aa59d833b24eeca7b
 refs/heads/revert-26776-subst-always-returns-a-type: 1b8e18fdd391903a348970a4c848995d4cdd789c
 refs/heads/tensorflow-merge: 8b854f62f80d4476cb383d43c4aac2001dde3cec

branches/master-rebranch/docs/SIL.rst

@@ -2525,7 +2525,9 @@ except that ``destroy_addr`` may be used even if ``%0`` is of an
 address-only type.  This does not deallocate memory; it only destroys the
 pointed-to value, leaving the memory uninitialized.
 
-If ``T`` is a trivial type, then ``destroy_addr`` is a no-op.
+If ``T`` is a trivial type, then ``destroy_addr`` is a no-op. However, even a
+memory location ``%a`` with a trivial type must not be accessed after a
+``destroy_addr %a``.
 
 index_addr
 ``````````

branches/master-rebranch/include/swift/SIL/MemoryLifetime.h

@@ -131,12 +131,23 @@ class MemoryLocations {
     /// \endcode
     int parentIdx;
 
+  private:
+    friend class MemoryLocations;
+
     /// Used to decide if a location is completely covered by its sub-locations.
     ///
     /// -1 means: not yet initialized.
     int numFieldsNotCoveredBySubfields = -1;
 
+    /// The same as ``numFieldsNotCoveredBySubfields``, just for non-trivial
+    /// fields.
+    ///
+    /// -1 means: not yet initialized.
+    int numNonTrivialFieldsNotCovered = -1;
+
     Location(SILValue val, unsigned index, int parentIdx = -1);
+
+    void updateFieldCounters(SILType ty, int increment);
   };
 
 private:
@@ -156,6 +167,9 @@ class MemoryLocations {
   /// small. They can be handled separately with handleSingleBlockLocations().
   llvm::SmallVector<SingleValueInstruction *, 16> singleBlockLocations;
 
+  /// The bit-set of locations for which numNonTrivialFieldsNotCovered is > 0.
+  Bits nonTrivialLocations;
+
 public:
   MemoryLocations() {}
 
@@ -220,6 +234,10 @@ class MemoryLocations {
   void handleSingleBlockLocations(
                        std::function<void (SILBasicBlock *block)> handlerFunc);
 
+  /// Returns the set of locations for which have non trivial fields which are
+  /// not covered by sub-fields.
+  const Bits &getNonTrivialLocations();
+
   /// Debug dump the MemoryLifetime internals.
   void dump() const;
 
@@ -249,11 +267,6 @@ class MemoryLocations {
 
   /// Calculates Location::numFieldsNotCoveredBySubfields
   void initFieldsCounter(Location &loc);
-
-  /// Only memory locations which store a non-trivial type are considered.
-  bool shouldTrackLocation(SILType type, SILFunction *inFunction) {
-    return !type.isTrivial(*inFunction);
-  }
 };
 
 /// The MemoryDataflow utility calculates global dataflow of memory locations.

branches/master-rebranch/lib/AST/ASTMangler.cpp

@@ -736,9 +736,9 @@ void ASTMangler::appendOpaqueDeclName(const OpaqueTypeDecl *opaqueDecl) {
   if (canSymbolicReference(opaqueDecl)) {
     appendSymbolicReference(opaqueDecl);
   } else if (auto namingDecl = opaqueDecl->getNamingDecl()) {
-    llvm::SaveAndRestore<CanGenericSignature> savedSignature(
-        CurGenericSignature);
+    CanGenericSignature savedSignature = CurGenericSignature;
     appendEntity(namingDecl);
+    CurGenericSignature = savedSignature;
     appendOperator("QO");
   } else {
     llvm_unreachable("todo: independent opaque type decls");
@@ -2667,11 +2667,11 @@ void ASTMangler::appendConcreteProtocolConformance(
             opaqueSignature->getConformanceAccessPath(opaqueTypeParam, proto);
 
         // Append the conformance access path with the signature of the opaque type.
-        {
-          llvm::SaveAndRestore<CanGenericSignature> savedSignature(
-              CurGenericSignature, opaqueSignature->getCanonicalSignature());
-          appendDependentProtocolConformance(conformanceAccessPath);
-        }
+        CanGenericSignature savedSignature = CurGenericSignature;
+        CurGenericSignature = opaqueSignature->getCanonicalSignature();
+        appendDependentProtocolConformance(conformanceAccessPath);
+        CurGenericSignature = savedSignature;
+
         appendType(canType);
         appendOperator("HO");
       } else {