From: Pete Cooper <peter_cooper@apple.com>
Date: Fri, 29 May 2015 17:19:11 +0000 (+0000)
Subject: Fix crash in MCExpr::print.
X-Git-Tag: android-x86-7.1-r4~47574
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=b2faffd63aa29617402aad745d8aabbd60f67a96;p=android-x86%2Fexternal-llvm.git

Fix crash in MCExpr::print.

Symbols are no longer required to be named, but this leads to a crash here if an
unnamed symbol checks that its first character is '$'.

Change the code to first check for a name, then check its first character.

No test case i'm afraid as this is debugging code, but any test case with temp labels
and 'llc --debug --filetype=obj' would have crashed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238579 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/MC/MCExpr.cpp b/lib/MC/MCExpr.cpp
index 1c0dc3f703a..1b328ac436f 100644
--- a/lib/MC/MCExpr.cpp
+++ b/lib/MC/MCExpr.cpp
@@ -43,7 +43,7 @@ void MCExpr::print(raw_ostream &OS) const {
     const MCSymbol &Sym = SRE.getSymbol();
     // Parenthesize names that start with $ so that they don't look like
     // absolute names.
-    bool UseParens = Sym.getName()[0] == '$';
+    bool UseParens = !Sym.getName().empty() && Sym.getName()[0] == '$';
     if (UseParens)
       OS << '(' << Sym << ')';
     else