[api-digester] Add '-protocol-requirement-white-list' option to the digester for when diagnosing API breakage in SDKs

This option access a file that lists protocol names that are 'whitelisted' for getting new protocol requirements.
This allows the SDK checker to avoid flagging protocol method additions for protocols that we know are not intended
for user classes to conform to.

Author: akyrtzi

test/api-digester/Inputs/Foo-new-version/foo.h

@@ -9,6 +9,11 @@
   -(void) someOptionalFunctionFromProt;
 @end
 
+@protocol AnotherObjcProt
+  -(void) anotherFunctionFromProt;
+  -(void) anotherFunctionFromProt2;
+@end
+
 @interface ClangInterface: NSObject <ObjcProt>
 - (void)someFunction;
 @end

test/api-digester/Inputs/Foo-prot-whitelist.txt

@@ -0,0 +1 @@
+AnotherObjcProt

test/api-digester/Inputs/Foo/foo.h

@@ -4,6 +4,10 @@
   -(void) someFunctionFromProt;
 @end
 
+@protocol AnotherObjcProt
+  -(void) anotherFunctionFromProt;
+@end
+
 @interface ClangInterface: NSObject <ObjcProt>
 - (void)someFunction;
 @end

test/api-digester/Outputs/clang-module-dump.txt

@@ -3,6 +3,47 @@
   "name": "TopLevel",
   "printedName": "TopLevel",
   "children": [
+    {
+      "kind": "TypeDecl",
+      "name": "AnotherObjcProt",
+      "printedName": "AnotherObjcProt",
+      "children": [
+        {
+          "kind": "Function",
+          "name": "anotherFunctionFromProt",
+          "printedName": "anotherFunctionFromProt()",
+          "children": [
+            {
+              "kind": "TypeNameAlias",
+              "name": "Void",
+              "printedName": "Void",
+              "children": [
+                {
+                  "kind": "TypeNominal",
+                  "name": "Void",
+                  "printedName": "()"
+                }
+              ]
+            }
+          ],
+          "declKind": "Func",
+          "usr": "c:objc(pl)AnotherObjcProt(im)anotherFunctionFromProt",
+          "moduleName": "Foo",
+          "genericSig": "<Self where Self : AnotherObjcProt>",
+          "protocolReq": true,
+          "declAttributes": [
+            "ObjC"
+          ],
+          "funcSelfKind": "NonMutating"
+        }
+      ],
+      "declKind": "Protocol",
+      "usr": "c:objc(pl)AnotherObjcProt",
+      "moduleName": "Foo",
+      "declAttributes": [
+        "ObjC"
+      ]
+    },
     {
       "kind": "TypeDecl",
       "name": "ClangInterface",

test/api-digester/compare-clang-dump.swift

@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t.module-cache)
 // RUN: %api-digester -dump-sdk -module Foo -o %t.dump1.json -module-cache-path %t.module-cache %clang-importer-sdk-nosource -I %S/Inputs/Foo -avoid-location
 // RUN: %api-digester -dump-sdk -module Foo -o %t.dump2.json -module-cache-path %t.module-cache %clang-importer-sdk-nosource -I %S/Inputs/Foo-new-version -avoid-location
-// RUN: %api-digester -diagnose-sdk -print-module --input-paths %t.dump1.json -input-paths %t.dump2.json -o %t.result
+// RUN: %api-digester -diagnose-sdk -protocol-requirement-white-list %S/Inputs/Foo-prot-whitelist.txt -print-module --input-paths %t.dump1.json -input-paths %t.dump2.json -o %t.result
 
 // RUN: %clang -E -P -x c %S/Outputs/Foo-diff.txt -o - | sed '/^\s*$/d' > %t.expected
 // RUN: %clang -E -P -x c %t.result -o - | sed '/^\s*$/d' > %t.result.tmp

tools/swift-api-digester/swift-api-digester.cpp

@@ -63,6 +63,10 @@ static llvm::cl::opt<std::string>
 ModuleList("module-list-file",
            llvm::cl::desc("File containing a new-line separated list of modules"));
 
+static llvm::cl::opt<std::string>
+ProtReqWhiteList("protocol-requirement-white-list",
+           llvm::cl::desc("File containing a new-line separated list of protocol names"));
+
 static llvm::cl::opt<std::string>
 OutputFile("o", llvm::cl::desc("Output file"));
 
@@ -927,6 +931,7 @@ class PrunePass : public MatchedNodeListener, public SDKTreeDiffPass {
 
   SDKContext &Ctx;
   UpdatedNodesMap &UpdateMap;
+  llvm::StringSet<> ProtocolReqWhitelist;
 
   static void printSpaces(llvm::raw_ostream &OS, SDKNode *N) {
     assert(N);
@@ -959,6 +964,10 @@ class PrunePass : public MatchedNodeListener, public SDKTreeDiffPass {
 
 public:
   PrunePass(SDKContext &Ctx): Ctx(Ctx), UpdateMap(Ctx.getNodeUpdateMap()) {}
+  PrunePass(SDKContext &Ctx, llvm::StringSet<> prWhitelist):
+    Ctx(Ctx),
+    UpdateMap(Ctx.getNodeUpdateMap()),
+    ProtocolReqWhitelist(std::move(prWhitelist)) {}
 
   void foundMatch(NodePtr Left, NodePtr Right, NodeMatchReason Reason) override {
     if (options::Verbose)
@@ -985,6 +994,12 @@ class PrunePass : public MatchedNodeListener, public SDKTreeDiffPass {
             if (ATD->getDefault())
               ShouldComplain = false;
           }
+          if (ShouldComplain &&
+              ProtocolReqWhitelist.count(D->getParent()->getAs<SDKNodeDecl>()->getFullyQualifiedName())) {
+            // Ignore protocol requirement additions if the protocol has been added
+            // to the whitelist.
+            ShouldComplain = false;
+          }
           if (ShouldComplain)
             Ctx.getDiags().diagnose(SourceLoc(), diag::protocol_req_added,
                                     D->getScreenInfo());
@@ -2027,7 +2042,8 @@ static void findTypeMemberDiffs(NodePtr leftSDKRoot, NodePtr rightSDKRoot,
 
 static int diagnoseModuleChange(StringRef LeftPath, StringRef RightPath,
                                 StringRef OutputPath,
-                                CheckerOptions Opts) {
+                                CheckerOptions Opts,
+                                llvm::StringSet<> ProtocolReqWhitelist) {
   if (!fs::exists(LeftPath)) {
     llvm::errs() << LeftPath << " does not exist\n";
     return 1;
@@ -2055,7 +2071,7 @@ static int diagnoseModuleChange(StringRef LeftPath, StringRef RightPath,
   auto RightModule = RightCollector.getSDKRoot();
   TypeAliasDiffFinder(LeftModule, RightModule,
                       Ctx.getTypeAliasUpdateMap()).search();
-  PrunePass Prune(Ctx);
+  PrunePass Prune(Ctx, std::move(ProtocolReqWhitelist));
   Prune.pass(LeftModule, RightModule);
   ChangeRefinementPass RefinementPass(Ctx.getNodeUpdateMap());
   RefinementPass.pass(LeftModule, RightModule);
@@ -2182,7 +2198,7 @@ static int compareSDKs(StringRef LeftPath, StringRef RightPath,
 static int readFileLineByLine(StringRef Path, llvm::StringSet<> &Lines) {
   auto FileBufOrErr = llvm::MemoryBuffer::getFile(Path);
   if (!FileBufOrErr) {
-    llvm::errs() << "error opening file: "
+    llvm::errs() << "error opening file '" << Path << "': "
       << FileBufOrErr.getError().message() << '\n';
     return 1;
   }
@@ -2347,19 +2363,26 @@ int main(int argc, char *argv[]) {
     return (prepareForDump(argv[0], InitInvok, Modules)) ? 1 :
       dumpSDKContent(InitInvok, Modules, options::OutputFile, Opts);
   case ActionType::CompareSDKs:
-  case ActionType::DiagnoseSDKs:
+  case ActionType::DiagnoseSDKs: {
     if (options::SDKJsonPaths.size() != 2) {
       llvm::errs() << "Only two SDK versions can be compared\n";
       llvm::cl::PrintHelpMessage();
       return 1;
     }
+    llvm::StringSet<> protocolWhitelist;
+    if (!options::ProtReqWhiteList.empty()) {
+      if (readFileLineByLine(options::ProtReqWhiteList, protocolWhitelist))
+          return 1;
+    }
     if (options::Action == ActionType::CompareSDKs)
       return compareSDKs(options::SDKJsonPaths[0], options::SDKJsonPaths[1],
                          options::OutputFile, IgnoredUsrs, Opts);
     else
       return diagnoseModuleChange(options::SDKJsonPaths[0],
                                   options::SDKJsonPaths[1],
-                                  options::OutputFile, Opts);
+                                  options::OutputFile, Opts,
+                                  std::move(protocolWhitelist));
+  }
   case ActionType::DeserializeSDK:
   case ActionType::DeserializeDiffItems: {
     if (options::SDKJsonPaths.size() != 1) {