vendor/clang/clang-trunk-r351319

3 files changed, 57 insertions, 13 deletions

diff --git a/lib/Tooling/Core/Diagnostic.cpp b/lib/Tooling/Core/Diagnostic.cpp
index 9e4833f2eff4..e3a33d9a3755 100644
--- a/lib/Tooling/Core/Diagnostic.cpp
+++ b/lib/Tooling/Core/Diagnostic.cpp
@@ -23,10 +23,15 @@ DiagnosticMessage::DiagnosticMessage(llvm::StringRef Message)
 DiagnosticMessage::DiagnosticMessage(llvm::StringRef Message,
                                      const SourceManager &Sources,
                                      SourceLocation Loc)
-    : Message(Message) {
+    : Message(Message), FileOffset(0) {
   assert(Loc.isValid() && Loc.isFileID());
   FilePath = Sources.getFilename(Loc);
-  FileOffset = Sources.getFileOffset(Loc);
+
+  // Don't store offset in the scratch space. It doesn't tell anything to the
+  // user. Moreover, it depends on the history of macro expansions and thus
+  // prevents deduplication of warnings in headers.
+  if (!FilePath.empty())
+    FileOffset = Sources.getFileOffset(Loc);
 }
 
 Diagnostic::Diagnostic(llvm::StringRef DiagnosticName,
diff --git a/lib/Tooling/Core/Lookup.cpp b/lib/Tooling/Core/Lookup.cpp
index 6edf61b8050d..cc448d144e2c 100644
--- a/lib/Tooling/Core/Lookup.cpp
+++ b/lib/Tooling/Core/Lookup.cpp
@@ -14,6 +14,7 @@
 #include "clang/Tooling/Core/Lookup.h"
 #include "clang/AST/Decl.h"
 #include "clang/AST/DeclCXX.h"
+#include "clang/AST/DeclarationName.h"
 using namespace clang;
 using namespace clang::tooling;
 
@@ -114,6 +115,37 @@ static bool isFullyQualified(const NestedNameSpecifier *NNS) {
   return false;
 }
 
+// Returns true if spelling symbol \p QName as \p Spelling in \p UseContext is
+// ambiguous. For example, if QName is "::y::bar" and the spelling is "y::bar"
+// in `UseContext` "a" that contains a nested namespace "a::y", then "y::bar"
+// can be resolved to ::a::y::bar, which can cause compile error.
+// FIXME: consider using namespaces.
+static bool isAmbiguousNameInScope(StringRef Spelling, StringRef QName,
+                                   const DeclContext &UseContext) {
+  assert(QName.startswith("::"));
+  if (Spelling.startswith("::"))
+    return false;
+
+  // Lookup the first component of Spelling in all enclosing namespaces and
+  // check if there is any existing symbols with the same name but in different
+  // scope.
+  StringRef Head = Spelling.split("::").first;
+
+  llvm::SmallVector<const NamespaceDecl *, 4> UseNamespaces =
+      getAllNamedNamespaces(&UseContext);
+  auto &AST = UseContext.getParentASTContext();
+  StringRef TrimmedQName = QName.substr(2);
+  for (const auto *NS : UseNamespaces) {
+    auto LookupRes = NS->lookup(DeclarationName(&AST.Idents.get(Head)));
+    if (!LookupRes.empty()) {
+      for (const NamedDecl *Res : LookupRes)
+        if (!TrimmedQName.startswith(Res->getQualifiedNameAsString()))
+          return true;
+    }
+  }
+  return false;
+}
+
 std::string tooling::replaceNestedName(const NestedNameSpecifier *Use,
                                        const DeclContext *UseContext,
                                        const NamedDecl *FromDecl,
@@ -146,6 +178,14 @@ std::string tooling::replaceNestedName(const NestedNameSpecifier *Use,
   // figure out how good a namespace match we have with our destination type.
   // We work backwards (from most specific possible namespace to least
   // specific).
-  return getBestNamespaceSubstr(UseContext, ReplacementString,
-                                isFullyQualified(Use));
+  StringRef Suggested = getBestNamespaceSubstr(UseContext, ReplacementString,
+                                               isFullyQualified(Use));
+  // Use the fully qualified name if the suggested name is ambiguous.
+  // FIXME: consider re-shortening the name until the name is not ambiguous. We
+  // are not doing this because ambiguity is pretty bad and we should not try to
+  // be clever in handling such cases. Making this noticeable to users seems to
+  // be a better option.
+  return isAmbiguousNameInScope(Suggested, ReplacementString, *UseContext)
+             ? ReplacementString
+             : Suggested;
 }
diff --git a/lib/Tooling/Core/Replacement.cpp b/lib/Tooling/Core/Replacement.cpp
index 67e2dcfd73c1..3b7e39814afa 100644
--- a/lib/Tooling/Core/Replacement.cpp
+++ b/lib/Tooling/Core/Replacement.cpp
@@ -19,7 +19,6 @@
 #include "clang/Basic/FileSystemOptions.h"
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Basic/SourceManager.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Lex/Lexer.h"
 #include "clang/Rewrite/Core/RewriteBuffer.h"
 #include "clang/Rewrite/Core/Rewriter.h"
@@ -29,6 +28,7 @@
 #include "llvm/Support/Error.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Support/raw_ostream.h"
 #include <algorithm>
 #include <cassert>
@@ -483,12 +483,11 @@ Replacements Replacements::merge(const Replacements &ReplacesToMerge) const {
 // Returns a set of non-overlapping and sorted ranges that is equivalent to
 // \p Ranges.
 static std::vector<Range> combineAndSortRanges(std::vector<Range> Ranges) {
-  llvm::sort(Ranges.begin(), Ranges.end(),
-             [](const Range &LHS, const Range &RHS) {
-               if (LHS.getOffset() != RHS.getOffset())
-                 return LHS.getOffset() < RHS.getOffset();
-               return LHS.getLength() < RHS.getLength();
-            });
+  llvm::sort(Ranges, [](const Range &LHS, const Range &RHS) {
+    if (LHS.getOffset() != RHS.getOffset())
+      return LHS.getOffset() < RHS.getOffset();
+    return LHS.getLength() < RHS.getLength();
+  });
   std::vector<Range> Result;
   for (const auto &R : Ranges) {
     if (Result.empty() ||
@@ -584,8 +583,8 @@ llvm::Expected<std::string> applyAllReplacements(StringRef Code,
   if (Replaces.empty())
     return Code.str();
 
-  IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem(
-      new vfs::InMemoryFileSystem);
+  IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem(
+      new llvm::vfs::InMemoryFileSystem);
   FileManager Files(FileSystemOptions(), InMemoryFileSystem);
   DiagnosticsEngine Diagnostics(
       IntrusiveRefCntPtr<DiagnosticIDs>(new DiagnosticIDs),