[AST] Extract Decl::printNestedNameSpecifier helper from Decl::printQualifiedName

Summary:
To be used in clangd, e.g. in D66647.
Currently the alternative to this function is doing string manipulation on results of `printQualifiedName`, which is
hard-to-impossible to get right in presence of template arguments.

Reviewers: kadircet, aaron.ballman

Reviewed By: kadircet, aaron.ballman

Subscribers: aaron.ballman, usaxena95, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D67825

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@372863 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 58 insertions, 12 deletions

diff --git a/unittests/AST/NamedDeclPrinterTest.cpp b/unittests/AST/NamedDeclPrinterTest.cpp
index a50626517f..a5c3e19055 100644
--- a/unittests/AST/NamedDeclPrinterTest.cpp
+++ b/unittests/AST/NamedDeclPrinterTest.cpp
@@ -16,9 +16,12 @@
 //===----------------------------------------------------------------------===//
 
 #include "clang/AST/ASTContext.h"
+#include "clang/AST/Decl.h"
+#include "clang/AST/PrettyPrinter.h"
 #include "clang/ASTMatchers/ASTMatchFinder.h"
 #include "clang/Tooling/Tooling.h"
 #include "llvm/ADT/SmallString.h"
+#include "llvm/Support/raw_ostream.h"
 #include "gtest/gtest.h"
 
 using namespace clang;
@@ -30,11 +33,12 @@ namespace {
 class PrintMatch : public MatchFinder::MatchCallback {
   SmallString<1024> Printed;
   unsigned NumFoundDecls;
-  bool SuppressUnwrittenScope;
+  std::function<void(llvm::raw_ostream &OS, const NamedDecl *)> Printer;
 
 public:
-  explicit PrintMatch(bool suppressUnwrittenScope)
-    : NumFoundDecls(0), SuppressUnwrittenScope(suppressUnwrittenScope) {}
+  explicit PrintMatch(
+      std::function<void(llvm::raw_ostream &OS, const NamedDecl *)> Printer)
+      : NumFoundDecls(0), Printer(std::move(Printer)) {}
 
   void run(const MatchFinder::MatchResult &Result) override {
     const NamedDecl *ND = Result.Nodes.getNodeAs<NamedDecl>("id");
@@ -45,9 +49,7 @@ public:
       return;
 
     llvm::raw_svector_ostream Out(Printed);
-    PrintingPolicy Policy = Result.Context->getPrintingPolicy();
-    Policy.SuppressUnwrittenScope = SuppressUnwrittenScope;
-    ND->printQualifiedName(Out, Policy);
+    Printer(Out, ND);
   }
 
   StringRef getPrinted() const {
@@ -59,12 +61,12 @@ public:
   }
 };
 
-::testing::AssertionResult
-PrintedNamedDeclMatches(StringRef Code, const std::vector<std::string> &Args,
-                        bool SuppressUnwrittenScope,
-                        const DeclarationMatcher &NodeMatch,
-                        StringRef ExpectedPrinted, StringRef FileName) {
-  PrintMatch Printer(SuppressUnwrittenScope);
+::testing::AssertionResult PrintedDeclMatches(
+    StringRef Code, const std::vector<std::string> &Args,
+    const DeclarationMatcher &NodeMatch, StringRef ExpectedPrinted,
+    StringRef FileName,
+    std::function<void(llvm::raw_ostream &, const NamedDecl *)> Print) {
+  PrintMatch Printer(std::move(Print));
   MatchFinder Finder;
   Finder.addMatcher(NodeMatch, &Printer);
   std::unique_ptr<FrontendActionFactory> Factory =
@@ -92,6 +94,21 @@ PrintedNamedDeclMatches(StringRef Code, const std::vector<std::string> &Args,
 }
 
 ::testing::AssertionResult
+PrintedNamedDeclMatches(StringRef Code, const std::vector<std::string> &Args,
+                        bool SuppressUnwrittenScope,
+                        const DeclarationMatcher &NodeMatch,
+                        StringRef ExpectedPrinted, StringRef FileName) {
+  return PrintedDeclMatches(Code, Args, NodeMatch, ExpectedPrinted, FileName,
+                            [=](llvm::raw_ostream &Out, const NamedDecl *ND) {
+                              auto Policy =
+                                  ND->getASTContext().getPrintingPolicy();
+                              Policy.SuppressUnwrittenScope =
+                                  SuppressUnwrittenScope;
+                              ND->printQualifiedName(Out, Policy);
+                            });
+}
+
+::testing::AssertionResult
 PrintedNamedDeclCXX98Matches(StringRef Code, StringRef DeclName,
                              StringRef ExpectedPrinted) {
   std::vector<std::string> Args(1, "-std=c++98");
@@ -127,6 +144,17 @@ PrintedWrittenPropertyDeclObjCMatches(StringRef Code, StringRef DeclName,
                                  "input.m");
 }
 
+::testing::AssertionResult
+PrintedNestedNameSpecifierMatches(StringRef Code, StringRef DeclName,
+                                  StringRef ExpectedPrinted) {
+  std::vector<std::string> Args{"-std=c++11"};
+  return PrintedDeclMatches(Code, Args, namedDecl(hasName(DeclName)).bind("id"),
+                            ExpectedPrinted, "input.cc",
+                            [](llvm::raw_ostream &Out, const NamedDecl *D) {
+                              D->printNestedNameSpecifier(Out);
+                            });
+}
+
 } // unnamed namespace
 
 TEST(NamedDeclPrinter, TestNamespace1) {
@@ -223,3 +251,21 @@ R"(
     "property",
     "Obj::property"));
 }
+
+TEST(NamedDeclPrinter, NestedNameSpecifierSimple) {
+  const char *Code =
+      R"(
+  namespace foo { namespace bar { void func(); }  }
+)";
+  ASSERT_TRUE(PrintedNestedNameSpecifierMatches(Code, "func", "foo::bar::"));
+}
+
+TEST(NamedDeclPrinter, NestedNameSpecifierTemplateArgs) {
+  const char *Code =
+      R"(
+        template <class T> struct vector;
+        template <> struct vector<int> { int method(); };
+)";
+  ASSERT_TRUE(
+      PrintedNestedNameSpecifierMatches(Code, "method", "vector<int>::"));
+}