commit 333ac7989785f95735b5b36affdd341fbd3b769b
author Sam McCall <sam.mccall@gmail.com> Tue Feb 12 10:38:45 2019 +0000
committer Sam McCall <sam.mccall@gmail.com> Tue Feb 12 10:38:45 2019 +0000
tree 757eb0ba9200a59464a8fd96979da26492fbb416
parent 43a715d3a5b1592c67a40d3404bc5fed2ca5e67b

[clangd] Fix use-after-free in XRefs

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@353821 91177308-0d34-0410-b5e6-96231b3b80d8

clangd/XRefs.cpp

diff --git a/clangd/XRefs.cpp b/clangd/XRefs.cpp
index 5c97c6a..b296a05 100644
--- a/clangd/XRefs.cpp
+++ b/clangd/XRefs.cpp
@@ -92,19 +92,18 @@
 
 // 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 @@
     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 @@
           // 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;
         }
       }