Fix arg-order bug and add assertions. (Windows manifested.)

Author: David Ungar

include/swift/AST/FineGrainedDependencies.h

@@ -390,17 +390,6 @@ template <typename NodeT> class InterfaceAndImplementationPair {
 
   InterfaceAndImplementationPair(NodeT *interface, NodeT *implementation)
       : interface(interface), implementation(implementation) {
-
-    if (!interface->getKey().isInterface()) {
-      llvm::errs() << "interface key is wrong: \n";
-      interface->dump();
-    }
-    if (!implementation->getKey().isImplementation()) {
-        llvm::errs() << "implementation key is wrong: \n";
-        implementation->dump();
-    }
-
-
     assert(
         interface->getKey().isInterface() &&
         implementation->getKey().isImplementation() &&
@@ -725,8 +714,29 @@ class SourceFileDepGraphNode : public DepGraphNode {
   bool verify() const {
     DepGraphNode::verify();
     assert(getIsProvides() || isDepends());
+    assert(verifySequenceNumber());
     return true;
   }
+
+  bool verifySequenceNumber() const {
+    const auto &k = getKey();
+    if (k.getKind() != NodeKind::sourceFileProvide)
+      return true;
+    switch (k.getAspect()) {
+    case DeclAspect::interface:
+      assert(getSequenceNumber() == sourceFileProvidesInterfaceSequenceNumber);
+      return true;
+    case DeclAspect::implementation:
+      assert(getSequenceNumber() ==
+             sourceFileProvidesImplementationSequenceNumber);
+      return true;
+    default:
+      llvm_unreachable("neither interface nor implementation");
+    }
+  }
+  static constexpr const size_t sourceFileProvidesInterfaceSequenceNumber = 0;
+  static constexpr const size_t sourceFileProvidesImplementationSequenceNumber =
+      1;
 };
 
 //==============================================================================
@@ -849,14 +859,14 @@ class SourceFileDepGraph {
   /// Ensure that when read, the graph is the same as what was written.
   bool verifyReadsWhatIsWritten(StringRef path) const;
 
+  bool verifySequenceNumber() const;
+
 private:
   void addNode(SourceFileDepGraphNode *n) {
     n->setSequenceNumber(allNodes.size());
-    assert(allNodes.size() < 2 ==
-               (n->getKey().getKind() == NodeKind::sourceFileProvide) &&
-           "First two and only first two nodes should be sourceFileProvide "
-           "nodes.");
     allNodes.push_back(n);
+    assert(n->verifySequenceNumber() &&
+           "Certain nodes must be in certain places");
   }
 };
 

lib/AST/FineGrainedDependencies.cpp

@@ -49,12 +49,11 @@ SourceFileDepGraph::getNode(size_t sequenceNumber) const {
 
 InterfaceAndImplementationPair<SourceFileDepGraphNode>
 SourceFileDepGraph::getSourceFileNodePair() const {
-  assert(getNode(0)->getKey().getKind() == NodeKind::sourceFileProvide &&
-         "First node must be sourceFileProvide.");
-  assert(getNode(1)->getKey().getKind() == NodeKind::sourceFileProvide &&
-         "Second node must be sourceFileProvide.");
-  return InterfaceAndImplementationPair<SourceFileDepGraphNode>(getNode(0),
-                                                                getNode(1));
+  return InterfaceAndImplementationPair<SourceFileDepGraphNode>(
+      getNode(
+          SourceFileDepGraphNode::sourceFileProvidesInterfaceSequenceNumber),
+      getNode(SourceFileDepGraphNode::
+                  sourceFileProvidesImplementationSequenceNumber));
 }
 
 StringRef SourceFileDepGraph::getSwiftDepsOfJobThatProducedThisGraph() const {
@@ -82,13 +81,16 @@ SourceFileDepGraph::findExistingNodePairOrCreateAndAddIfNew(
   const std::string &name = std::get<1>(contextNameFingerprint);
   const Optional<std::string> &fingerprint =
       std::get<2>(contextNameFingerprint);
+  auto *interfaceNode = findExistingNodeOrCreateIfNew(
+      DependencyKey(k, DeclAspect::interface, context, name), fingerprint,
+      true /* = isProvides */);
+  auto *implementationNode = findExistingNodeOrCreateIfNew(
+      DependencyKey(k, DeclAspect::implementation, context, name), fingerprint,
+      true /* = isProvides */);
+
   InterfaceAndImplementationPair<SourceFileDepGraphNode> nodePair{
-      findExistingNodeOrCreateIfNew(
-          DependencyKey(k, DeclAspect::interface, context, name), fingerprint,
-          true /* = isProvides */),
-      findExistingNodeOrCreateIfNew(
-          DependencyKey(k, DeclAspect::implementation, context, name),
-          fingerprint, true /* = isProvides */)};
+      interfaceNode, implementationNode};
+
   // if interface changes, have to rebuild implementation.
   // This dependency used to be represented by
   // addArc(nodePair.getInterface(), nodePair.getImplementation());