From 251da88db88aba0393470694a1a2739f0daf3182 Mon Sep 17 00:00:00 2001
From: Alexey Samsonov <vonosmas@gmail.com>
Date: Tue, 2 Sep 2014 17:25:29 +0000
Subject: [PATCH] Fix left shifts by too large exponents in MCParser (which
happened only on error recovery path).
This bug was reported by UBSan.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216915 91177308-0d34-0410-b5e6-96231b3b80d8
---
lib/MC/MCParser/AsmParser.cpp | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/lib/MC/MCParser/AsmParser.cpp b/lib/MC/MCParser/AsmParser.cpp
index a1b469d6797..388d2fc3452 100644
--- a/lib/MC/MCParser/AsmParser.cpp
+++ b/lib/MC/MCParser/AsmParser.cpp
@@ -2601,13 +2601,14 @@ bool AsmParser::parseDirectiveFill() {
if (!isUInt<32>(FillExpr) && FillSize > 4)
Warning(ExprLoc, "'.fill' directive pattern has been truncated to 32-bits");
- int64_t NonZeroFillSize = FillSize > 4 ? 4 : FillSize;
- FillExpr &= ~0ULL >> (64 - NonZeroFillSize * 8);
-
- for (uint64_t i = 0, e = NumValues; i != e; ++i) {
- getStreamer().EmitIntValue(FillExpr, NonZeroFillSize);
- if (NonZeroFillSize < FillSize)
- getStreamer().EmitIntValue(0, FillSize - NonZeroFillSize);
+ if (NumValues > 0) {
+ int64_t NonZeroFillSize = FillSize > 4 ? 4 : FillSize;
+ FillExpr &= ~0ULL >> (64 - NonZeroFillSize * 8);
+ for (uint64_t i = 0, e = NumValues; i != e; ++i) {
+ getStreamer().EmitIntValue(FillExpr, NonZeroFillSize);
+ if (NonZeroFillSize < FillSize)
+ getStreamer().EmitIntValue(0, FillSize - NonZeroFillSize);
+ }
}
return false;