From c4a3768bd227fb4433e32e17bab699eabf7cc793 Mon Sep 17 00:00:00 2001
From: Richard Trieu <rtrieu@google.com>
Date: Sat, 4 Jan 2014 01:57:42 +0000
Subject: [PATCH] Ignore qualified templated functions for
 -Winfinite-recursion.  This treats functions like Foo<5>::run() the same way
 as run<5>() for this warning.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@198470 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Sema/AnalysisBasedWarnings.cpp       | 12 ++++++++++++
 test/SemaCXX/warn-infinite-recursion.cpp | 23 +++++++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/lib/Sema/AnalysisBasedWarnings.cpp b/lib/Sema/AnalysisBasedWarnings.cpp
index 57c0ac311c..72f8ee1d29 100644
--- a/lib/Sema/AnalysisBasedWarnings.cpp
+++ b/lib/Sema/AnalysisBasedWarnings.cpp
@@ -116,6 +116,18 @@ static void checkForFunctionCall(Sema &S, const FunctionDecl *FD,
       const CallExpr *CE = dyn_cast<CallExpr>(I->getAs<CFGStmt>()->getStmt());
       if (CE && CE->getCalleeDecl() &&
           CE->getCalleeDecl()->getCanonicalDecl() == FD) {
+
+        // Skip function calls which are qualified with a templated class.
+        if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(
+                CE->getCallee()->IgnoreParenImpCasts())) {
+          if (NestedNameSpecifier *NNS = DRE->getQualifier()) {
+            if (NNS->getKind() == NestedNameSpecifier::TypeSpec &&
+                isa<TemplateSpecializationType>(NNS->getAsType())) {
+               continue;
+            }
+          }
+        }
+
         if (const CXXMemberCallExpr *MCE = dyn_cast<CXXMemberCallExpr>(CE)) {
           if (isa<CXXThisExpr>(MCE->getImplicitObjectArgument()) ||
               !MCE->getMethodDecl()->isVirtual()) {
diff --git a/test/SemaCXX/warn-infinite-recursion.cpp b/test/SemaCXX/warn-infinite-recursion.cpp
index 088d4ba3de..e1b7c5412e 100644
--- a/test/SemaCXX/warn-infinite-recursion.cpp
+++ b/test/SemaCXX/warn-infinite-recursion.cpp
@@ -127,3 +127,26 @@ int DoStuff() {
   return 0;
 }
 int stuff = DoStuff<0, 1>();
+
+template<int x>
+struct Wrapper {
+  static int run() {
+    // Similar to the above, Wrapper<0>::run() will discard the if statement.
+    if (x == 1)
+      return 0;
+    return Wrapper<x/2>::run();
+  }
+  static int run2() {  // expected-warning{{call itself}}
+    return run2();
+  }
+};
+
+template <int x>
+int test_wrapper() {
+  if (x != 0)
+    return Wrapper<x>::run() +
+           Wrapper<x>::run2();  // expected-note{{instantiation}}
+  return 0;
+}
+
+int wrapper_sum = test_wrapper<2>();  // expected-note{{instantiation}}
-- 
2.40.0