[clang-tools-extra] r353821 - [clangd] Fix use-after-free in XRefs

[Sam McCall via cfe-commits]

Author: sammccall
Date: Tue Feb 12 02:38:45 2019
New Revision: 353821

URL: http://llvm.org/viewvc/llvm-project?rev=353821&view=rev
Log:
[clangd] Fix use-after-free in XRefs

Modified:
    clang-tools-extra/trunk/clangd/XRefs.cpp

Modified: clang-tools-extra/trunk/clangd/XRefs.cpp
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clangd/XRefs.cpp?rev=353821&r1=353820&r2=353821&view=diff
==============================================================================
--- clang-tools-extra/trunk/clangd/XRefs.cpp (original)
+++ clang-tools-extra/trunk/clangd/XRefs.cpp Tue Feb 12 02:38:45 2019
@@ -92,19 +92,18 @@ SymbolLocation toIndexLocation(const Loc
 
 // Returns the preferred location between an AST location and an index location.
 SymbolLocation getPreferredLocation(const Location &ASTLoc,
-                                    const SymbolLocation &IdxLoc) {
+                                    const SymbolLocation &IdxLoc,
+                                    std::string &Scratch) {
   // Also use a dummy symbol for the index location so that other fields (e.g.
   // definition) are not factored into the preferrence.
   Symbol ASTSym, IdxSym;
   ASTSym.ID = IdxSym.ID = SymbolID("dummy_id");
-  std::string URIStore;
-  ASTSym.CanonicalDeclaration = toIndexLocation(ASTLoc, URIStore);
+  ASTSym.CanonicalDeclaration = toIndexLocation(ASTLoc, Scratch);
   IdxSym.CanonicalDeclaration = IdxLoc;
   auto Merged = mergeSymbol(ASTSym, IdxSym);
   return Merged.CanonicalDeclaration;
 }
 
-
 struct MacroDecl {
   llvm::StringRef Name;
   const MacroInfo *Info;
@@ -352,6 +351,7 @@ std::vector<LocatedSymbol> locateSymbolA
     LookupRequest QueryRequest;
     for (auto It : ResultIndex)
       QueryRequest.IDs.insert(It.first);
+    std::string Scratch;
     Index->lookup(QueryRequest, [&](const Symbol &Sym) {
       auto &R = Result[ResultIndex.lookup(Sym.ID)];
 
@@ -367,10 +367,10 @@ std::vector<LocatedSymbol> locateSymbolA
           // Use merge logic to choose AST or index declaration.
           // We only do this for declarations as definitions from AST
           // is generally preferred (e.g. definitions in main file).
-          if (auto Loc =
-                  toLSPLocation(getPreferredLocation(R.PreferredDeclaration,
-                                                     Sym.CanonicalDeclaration),
-                                *MainFilePath))
+          if (auto Loc = toLSPLocation(
+                  getPreferredLocation(R.PreferredDeclaration,
+                                       Sym.CanonicalDeclaration, Scratch),
+                  *MainFilePath))
             R.PreferredDeclaration = *Loc;
         }
       }