[AST/index] Introduce an option 'SuppressTemplateArgsInCXXConstructors' in printing policy.

Enable it for USRs and names when indexing.
Forward references can have different template argument names; including them
makes USRs and names unstable, since the name depends on whether we saw a forward reference or not.

llvm-svn: 260866

2 files changed, 25 insertions, 1 deletions

diff --git a/clang/lib/Index/IndexSymbol.cpp b/clang/lib/Index/IndexSymbol.cpp
index 95ae9776826..010ccd42a4a 100644
--- a/clang/lib/Index/IndexSymbol.cpp
+++ b/clang/lib/Index/IndexSymbol.cpp
@@ -11,6 +11,7 @@
 #include "clang/AST/DeclCXX.h"
 #include "clang/AST/DeclObjC.h"
 #include "clang/AST/DeclTemplate.h"
+#include "clang/AST/PrettyPrinter.h"
 
 using namespace clang;
 using namespace clang::index;
@@ -234,6 +235,24 @@ void index::printSymbolRoles(SymbolRoleSet Roles, raw_ostream &OS) {
   });
 }
 
+bool index::printSymbolName(const Decl *D, const LangOptions &LO,
+                            raw_ostream &OS) {
+  if (auto *ND = dyn_cast<NamedDecl>(D)) {
+    PrintingPolicy Policy(LO);
+    // Forward references can have different template argument names. Suppress
+    // the template argument names in constructors to make their name more
+    // stable.
+    Policy.SuppressTemplateArgsInCXXConstructors = true;
+    DeclarationName DeclName = ND->getDeclName();
+    if (DeclName.isEmpty())
+      return true;
+    DeclName.print(OS, Policy);
+    return false;
+  } else {
+    return true;
+  }
+}
+
 StringRef index::getSymbolKindString(SymbolKind K) {
   switch (K) {
   case SymbolKind::Unknown: return "<unknown>";
diff --git a/clang/lib/Index/USRGeneration.cpp b/clang/lib/Index/USRGeneration.cpp
index 3b2954f9770..c15838c76c6 100644
--- a/clang/lib/Index/USRGeneration.cpp
+++ b/clang/lib/Index/USRGeneration.cpp
@@ -210,7 +210,12 @@ void USRGenerator::VisitFunctionDecl(const FunctionDecl *D) {
     VisitTemplateParameterList(FunTmpl->getTemplateParameters());
   } else
     Out << "@F@";
-  D->printName(Out);
+
+  PrintingPolicy Policy(Context->getLangOpts());
+  // Forward references can have different template argument names. Suppress the
+  // template argument names in constructors to make their USR more stable.
+  Policy.SuppressTemplateArgsInCXXConstructors = true;
+  D->getDeclName().print(Out, Policy);
 
   ASTContext &Ctx = *Context;
   if (!Ctx.getLangOpts().CPlusPlus || D->isExternC())