[ClangImporter] Add various const

`getSelector` now takes a `const clang::IdentifierInfo *` `ArrayRef`.
Sprinkle a bunch of `const`s in.

Author: bnbarham

include/swift/ClangImporter/SwiftAbstractBasicReader.h

@@ -72,7 +72,7 @@ class DataStreamBasicReader
       return clang::Selector();
 
     unsigned numArgs = unsigned(numArgsPlusOne - 1);
-    SmallVector<clang::IdentifierInfo *, 4> chunks;
+    SmallVector<const clang::IdentifierInfo *, 4> chunks;
     for (unsigned i = 0, e = std::max(numArgs, 1U); i != e; ++i)
       chunks.push_back(asImpl().readIdentifier());
 

lib/ClangImporter/ClangImporter.cpp

@@ -1510,18 +1510,18 @@ ClangImporter::create(ASTContext &ctx,
   importer->Impl.objectAtIndexedSubscript
     = clangContext.Selectors.getUnarySelector(
         &clangContext.Idents.get("objectAtIndexedSubscript"));
-  clang::IdentifierInfo *setObjectAtIndexedSubscriptIdents[2] = {
-    &clangContext.Idents.get("setObject"),
-    &clangContext.Idents.get("atIndexedSubscript")
+  const clang::IdentifierInfo *setObjectAtIndexedSubscriptIdents[2] = {
+      &clangContext.Idents.get("setObject"),
+      &clangContext.Idents.get("atIndexedSubscript"),
   };
   importer->Impl.setObjectAtIndexedSubscript
     = clangContext.Selectors.getSelector(2, setObjectAtIndexedSubscriptIdents);
   importer->Impl.objectForKeyedSubscript
     = clangContext.Selectors.getUnarySelector(
         &clangContext.Idents.get("objectForKeyedSubscript"));
-  clang::IdentifierInfo *setObjectForKeyedSubscriptIdents[2] = {
-    &clangContext.Idents.get("setObject"),
-    &clangContext.Idents.get("forKeyedSubscript")
+  const clang::IdentifierInfo *setObjectForKeyedSubscriptIdents[2] = {
+      &clangContext.Idents.get("setObject"),
+      &clangContext.Idents.get("forKeyedSubscript"),
   };
   importer->Impl.setObjectForKeyedSubscript
     = clangContext.Selectors.getSelector(2, setObjectForKeyedSubscriptIdents);
@@ -2882,7 +2882,7 @@ ClangImporter::Implementation::exportSelector(DeclName name,
 
   clang::ASTContext &ctx = getClangASTContext();
 
-  SmallVector<clang::IdentifierInfo *, 8> pieces;
+  SmallVector<const clang::IdentifierInfo *, 8> pieces;
   pieces.push_back(exportName(name.getBaseIdentifier()).getAsIdentifierInfo());
 
   auto argNames = name.getArgumentNames();
@@ -2901,7 +2901,7 @@ ClangImporter::Implementation::exportSelector(DeclName name,
 
 clang::Selector
 ClangImporter::Implementation::exportSelector(ObjCSelector selector) {
-  SmallVector<clang::IdentifierInfo *, 4> pieces;
+  SmallVector<const clang::IdentifierInfo *, 4> pieces;
   for (auto piece : selector.getSelectorPieces())
     pieces.push_back(exportName(piece).getAsIdentifierInfo());
   return getClangASTContext().Selectors.getSelector(selector.getNumArgs(),
@@ -2917,7 +2917,7 @@ isPotentiallyConflictingSetter(const clang::ObjCProtocolDecl *proto,
   if (sel.getNumArgs() != 1)
     return false;
 
-  clang::IdentifierInfo *setterID = sel.getIdentifierInfoForSlot(0);
+  const clang::IdentifierInfo *setterID = sel.getIdentifierInfoForSlot(0);
   if (!setterID || !setterID->getName().starts_with("set"))
     return false;
 

lib/ClangImporter/ImportName.cpp

@@ -1431,7 +1431,7 @@ bool NameImporter::hasErrorMethodNameCollision(
   unsigned numArgs = selector.getNumArgs();
   assert(numArgs > 0);
 
-  SmallVector<clang::IdentifierInfo *, 4> chunks;
+  SmallVector<const clang::IdentifierInfo *, 4> chunks;
   for (unsigned i = 0, e = selector.getNumArgs(); i != e; ++i) {
     chunks.push_back(selector.getIdentifierInfoForSlot(i));
   }

tools/SourceKit/lib/SwiftLang/SwiftSourceDocInfo.cpp

@@ -1351,7 +1351,7 @@ getClangDeclarationName(const clang::NamedDecl *ND, NameTranslatingInfo &Info) {
       return clang::DeclarationName();
 
     ArrayRef<StringRef> Args = llvm::ArrayRef(Info.ArgNames);
-    std::vector<clang::IdentifierInfo *> Pieces;
+    std::vector<const clang::IdentifierInfo *> Pieces;
     for (unsigned i = 0; i < NumPieces; ++i) {
       if (i >= Info.ArgNames.size() || Info.ArgNames[i].empty()) {
         Pieces.push_back(OrigSel.getIdentifierInfoForSlot(i));