[llvm] r271748 - [llvm-profdata] Fix use-after-free from discarded MemoryBuffer (NFC)

[Vedant Kumar via llvm-commits]

Author: vedantk
Date: Fri Jun  3 18:12:38 2016
New Revision: 271748

URL: http://llvm.org/viewvc/llvm-project?rev=271748&view=rev
Log:
[llvm-profdata] Fix use-after-free from discarded MemoryBuffer (NFC)

Thanks to Justin Bogner for pointing this out!

Caught by ASAN.

Modified:
    llvm/trunk/tools/llvm-profdata/llvm-profdata.cpp

Modified: llvm/trunk/tools/llvm-profdata/llvm-profdata.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-profdata/llvm-profdata.cpp?rev=271748&r1=271747&r2=271748&view=diff
==============================================================================
--- llvm/trunk/tools/llvm-profdata/llvm-profdata.cpp (original)
+++ llvm/trunk/tools/llvm-profdata/llvm-profdata.cpp Fri Jun  3 18:12:38 2016
@@ -223,16 +223,19 @@ static WeightedFile parseWeightedFile(co
   return WeightedFile(FileName, Weight);
 }
 
-static void parseInputFilenamesFile(const StringRef &InputFilenamesFile,
-                                    WeightedFileVector &WFV) {
+static std::unique_ptr<MemoryBuffer>
+parseInputFilenamesFile(const StringRef &InputFilenamesFile,
+                        WeightedFileVector &WFV) {
   if (InputFilenamesFile == "")
-    return;
+    return {};
 
-  auto Buf = MemoryBuffer::getFileOrSTDIN(InputFilenamesFile);
-  if (!Buf)
-    exitWithErrorCode(Buf.getError(), InputFilenamesFile);
+  auto BufOrError = MemoryBuffer::getFileOrSTDIN(InputFilenamesFile);
+  if (!BufOrError)
+    exitWithErrorCode(BufOrError.getError(), InputFilenamesFile);
+
+  std::unique_ptr<MemoryBuffer> Buffer = std::move(*BufOrError);
+  StringRef Data = Buffer->getBuffer();
 
-  StringRef Data = Buf.get()->getBuffer();
   SmallVector<StringRef, 8> Entries;
   Data.split(Entries, '\n', /*MaxSplit=*/-1, /*KeepEmpty=*/false);
   for (const StringRef &FileWeightEntry : Entries) {
@@ -246,6 +249,8 @@ static void parseInputFilenamesFile(cons
     else
       WFV.emplace_back(parseWeightedFile(SanitizedEntry));
   }
+
+  return Buffer;
 }
 
 static int merge_main(int argc, const char *argv[]) {
@@ -288,7 +293,7 @@ static int merge_main(int argc, const ch
     WeightedInputs.push_back(WeightedFile(Filename, 1));
   for (StringRef WeightedFilename : WeightedInputFilenames)
     WeightedInputs.push_back(parseWeightedFile(WeightedFilename));
-  parseInputFilenamesFile(InputFilenamesFile, WeightedInputs);
+  auto Buf = parseInputFilenamesFile(InputFilenamesFile, WeightedInputs);
 
   if (WeightedInputs.empty())
     exitWithError("No input files specified. See " +