SourceMgr diagnotics printing: fix a bug where printing a fixit for a source

range that includes a tab character will cause out-of-bounds access to the
fixit string.

llvm-svn: 191563

2 files changed, 13 insertions, 1 deletions

diff --git a/llvm/lib/Support/SourceMgr.cpp b/llvm/lib/Support/SourceMgr.cpp
index fbcd8f980c1..d4b94f8cd5d 100644
--- a/llvm/lib/Support/SourceMgr.cpp
+++ b/llvm/lib/Support/SourceMgr.cpp
@@ -470,7 +470,7 @@ void SMDiagnostic::print(const char *ProgName, raw_ostream &S,
   if (FixItInsertionLine.empty())
     return;
   
-  for (size_t i = 0, e = FixItInsertionLine.size(), OutCol = 0; i != e; ++i) {
+  for (size_t i = 0, e = FixItInsertionLine.size(), OutCol = 0; i < e; ++i) {
     if (i >= LineContents.size() || LineContents[i] != '\t') {
       S << FixItInsertionLine[i];
       ++OutCol;
diff --git a/llvm/unittests/Support/SourceMgrTest.cpp b/llvm/unittests/Support/SourceMgrTest.cpp
index 9bc0cf67b75..2b69fe98444 100644
--- a/llvm/unittests/Support/SourceMgrTest.cpp
+++ b/llvm/unittests/Support/SourceMgrTest.cpp
@@ -160,3 +160,15 @@ TEST_F(SourceMgrTest, BasicFixit) {
             Output);
 }
 
+TEST_F(SourceMgrTest, FixitForTab) {
+  setMainBuffer("aaa\tbbb\nccc ddd\n", "file.in");
+  printMessage(getLoc(3), SourceMgr::DK_Error, "message", None,
+               makeArrayRef(SMFixIt(getRange(3, 1), "zzz")));
+
+  EXPECT_EQ("file.in:1:4: error: message\n"
+            "aaa     bbb\n"
+            "   ^^^^^\n"
+            "   zzz\n",
+            Output);
+}
+