From 5e3fa81ba51e6c674cf00eb1116314255d8ba83f Mon Sep 17 00:00:00 2001
From: Ivan Donchevskii <ivan.donchevskii@qt.io>
Date: Wed, 3 Jan 2018 10:04:37 +0000
Subject: [libclang] Fix cursors for functions with trailing return type

For the function declaration

auto foo5(Foo) -> Foo;
the parameter tokens were mapped to cursors representing the
FunctionDecl:

Keyword: "auto" [1:1 - 1:5] FunctionDecl=test5:1:6
Identifier: "test5" [1:6 - 1:11] FunctionDecl=test5:1:6
Punctuation: "(" [1:11 - 1:12] FunctionDecl=test5:1:6
Identifier: "X" [1:12 - 1:13] FunctionDecl=test5:1:6 // Ops, not a TypeRef
Punctuation: ")" [1:13 - 1:14] FunctionDecl=test5:1:6
Punctuation: "->" [1:15 - 1:17] FunctionDecl=test5:1:6
Identifier: "X" [1:18 - 1:19] TypeRef=struct X:7:8
Punctuation: ";" [1:19 - 1:20]

Fix this by ensuring that the trailing return type is not visited as
first.

Patch by Nikolai Kosjar.

Differential Revision: https://reviews.llvm.org/D40561

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@321698 91177308-0d34-0410-b5e6-96231b3b80d8
---
 tools/libclang/CIndex.cpp | 70 +++++++++++++++++++++++++++++------------------
 1 file changed, 43 insertions(+), 27 deletions(-)

(limited to 'tools')

diff --git a/tools/libclang/CIndex.cpp b/tools/libclang/CIndex.cpp
index 70bccc7eea..f73706dee1 100644
--- a/tools/libclang/CIndex.cpp
+++ b/tools/libclang/CIndex.cpp
@@ -782,12 +782,22 @@ bool CursorVisitor::VisitDeclaratorDecl(DeclaratorDecl *DD) {
     if (VisitNestedNameSpecifierLoc(QualifierLoc))
       return true;
 
-  return false;
-}
-
-/// \brief Compare two base or member initializers based on their source order.
-static int CompareCXXCtorInitializers(CXXCtorInitializer *const *X,
-                                      CXXCtorInitializer *const *Y) {
+  return false;
+}
+
+static bool HasTrailingReturnType(FunctionDecl *ND) {
+  const QualType Ty = ND->getType();
+  if (const FunctionType *AFT = Ty->getAs<FunctionType>()) {
+    if (const FunctionProtoType *FT = dyn_cast<FunctionProtoType>(AFT))
+      return FT->hasTrailingReturn();
+  }
+
+  return false;
+}
+
+/// \brief Compare two base or member initializers based on their source order.
+static int CompareCXXCtorInitializers(CXXCtorInitializer *const *X,
+                                      CXXCtorInitializer *const *Y) {
   return (*X)->getSourceOrder() - (*Y)->getSourceOrder();
 }
 
@@ -801,20 +811,22 @@ bool CursorVisitor::VisitFunctionDecl(FunctionDecl *ND) {
 
   if (TypeSourceInfo *TSInfo = ND->getTypeSourceInfo()) {
     // Visit the function declaration's syntactic components in the order
-    // written. This requires a bit of work.
-    TypeLoc TL = TSInfo->getTypeLoc().IgnoreParens();
-    FunctionTypeLoc FTL = TL.getAs<FunctionTypeLoc>();
-    
-    // If we have a function declared directly (without the use of a typedef),
-    // visit just the return type. Otherwise, just visit the function's type
-    // now.
-    if ((FTL && !isa<CXXConversionDecl>(ND) && Visit(FTL.getReturnLoc())) ||
-        (!FTL && Visit(TL)))
-      return true;
-    
-    // Visit the nested-name-specifier, if present.
-    if (NestedNameSpecifierLoc QualifierLoc = ND->getQualifierLoc())
-      if (VisitNestedNameSpecifierLoc(QualifierLoc))
+    // written. This requires a bit of work.
+    TypeLoc TL = TSInfo->getTypeLoc().IgnoreParens();
+    FunctionTypeLoc FTL = TL.getAs<FunctionTypeLoc>();
+    const bool HasTrailingRT = HasTrailingReturnType(ND);
+    
+    // If we have a function declared directly (without the use of a typedef),
+    // visit just the return type. Otherwise, just visit the function's type
+    // now.
+    if ((FTL && !isa<CXXConversionDecl>(ND) && !HasTrailingRT &&
+         Visit(FTL.getReturnLoc())) ||
+        (!FTL && Visit(TL)))
+      return true;
+
+    // Visit the nested-name-specifier, if present.
+    if (NestedNameSpecifierLoc QualifierLoc = ND->getQualifierLoc())
+      if (VisitNestedNameSpecifierLoc(QualifierLoc))
         return true;
     
     // Visit the declaration name.
@@ -824,13 +836,17 @@ bool CursorVisitor::VisitFunctionDecl(FunctionDecl *ND) {
     
     // FIXME: Visit explicitly-specified template arguments!
     
-    // Visit the function parameters, if we have a function type.
-    if (FTL && VisitFunctionTypeLoc(FTL, true))
-      return true;
-    
-    // FIXME: Attributes?
-  }
-  
+    // Visit the function parameters, if we have a function type.
+    if (FTL && VisitFunctionTypeLoc(FTL, true))
+      return true;
+
+    // Visit the function's trailing return type.
+    if (FTL && HasTrailingRT && Visit(FTL.getReturnLoc()))
+      return true;
+
+    // FIXME: Attributes?
+  }
+  
   if (ND->doesThisDeclarationHaveABody() && !ND->isLateTemplateParsed()) {
     if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(ND)) {
       // Find the initializers that were written in the source.
-- 
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