[pr17595] Fix a use after free.

Destroying the codegen also frees the path of the created object. Copy the
path to a std::string.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192787 91177308-0d34-0410-b5e6-96231b3b80d8

tools/gold/gold-plugin.cpp

@@ -427,9 +427,14 @@ static ld_plugin_status all_symbols_read_hook(void) {
       exit(0);
     }
   }
-  const char *objPath;
-  if (lto_codegen_compile_to_file(code_gen, &objPath)) {
-    (*message)(LDPL_ERROR, "Could not produce a combined object file\n");
+
+  std::string ObjPath;
+  {
+    const char *Temp;
+    if (lto_codegen_compile_to_file(code_gen, &Temp)) {
+      (*message)(LDPL_ERROR, "Could not produce a combined object file\n");
+    }
+    ObjPath = Temp;
   }
 
   lto_codegen_dispose(code_gen);
@@ -441,9 +446,9 @@ static ld_plugin_status all_symbols_read_hook(void) {
     }
   }
 
-  if ((*add_input_file)(objPath) != LDPS_OK) {
+  if ((*add_input_file)(ObjPath.c_str()) != LDPS_OK) {
     (*message)(LDPL_ERROR, "Unable to add .o file to the link.");
-    (*message)(LDPL_ERROR, "File left behind in: %s", objPath);
+    (*message)(LDPL_ERROR, "File left behind in: %s", ObjPath.c_str());
     return LDPS_ERR;
   }
 
@@ -454,7 +459,7 @@ static ld_plugin_status all_symbols_read_hook(void) {
   }
 
   if (options::obj_path.empty())
-    Cleanup.push_back(objPath);
+    Cleanup.push_back(ObjPath);
 
   return LDPS_OK;
 }