DataExtractor: Fix integer truncation issues in LEB128 extraction.

llvm-svn: 162201

2 files changed, 12 insertions, 3 deletions

diff --git a/llvm/lib/Support/DataExtractor.cpp b/llvm/lib/Support/DataExtractor.cpp
index dc21155a062..3d5cce05358 100644
--- a/llvm/lib/Support/DataExtractor.cpp
+++ b/llvm/lib/Support/DataExtractor.cpp
@@ -139,7 +139,7 @@ uint64_t DataExtractor::getULEB128(uint32_t *offset_ptr) const {
 
   while (isValidOffset(offset)) {
     byte = Data[offset++];
-    result |= (byte & 0x7f) << shift;
+    result |= uint64_t(byte & 0x7f) << shift;
     shift += 7;
     if ((byte & 0x80) == 0)
       break;
@@ -160,7 +160,7 @@ int64_t DataExtractor::getSLEB128(uint32_t *offset_ptr) const {
 
   while (isValidOffset(offset)) {
     byte = Data[offset++];
-    result |= (byte & 0x7f) << shift;
+    result |= uint64_t(byte & 0x7f) << shift;
     shift += 7;
     if ((byte & 0x80) == 0)
       break;
@@ -168,7 +168,7 @@ int64_t DataExtractor::getSLEB128(uint32_t *offset_ptr) const {
 
   // Sign bit of byte is 2nd high order bit (0x40)
   if (shift < 64 && (byte & 0x40))
-    result |= -(1 << shift);
+    result |= -(1ULL << shift);
 
   *offset_ptr = offset;
   return result;
diff --git a/llvm/unittests/Support/DataExtractorTest.cpp b/llvm/unittests/Support/DataExtractorTest.cpp
index 9813e465f7e..ec8bd3d18c8 100644
--- a/llvm/unittests/Support/DataExtractorTest.cpp
+++ b/llvm/unittests/Support/DataExtractorTest.cpp
@@ -16,6 +16,7 @@ namespace {
 const char numberData[] = "\x80\x90\xFF\xFF\x80\x00\x00\x00";
 const char stringData[] = "hellohello\0hello";
 const char leb128data[] = "\xA6\x49";
+const char bigleb128data[] = "\xAA\xA9\xFF\xAA\xFF\xAA\xFF\x4A";
 
 TEST(DataExtractorTest, OffsetOverflow) {
   DataExtractor DE(StringRef(numberData, sizeof(numberData)-1), false, 8);
@@ -106,6 +107,14 @@ TEST(DataExtractorTest, LEB128) {
   offset = 0;
   EXPECT_EQ(-7002LL, DE.getSLEB128(&offset));
   EXPECT_EQ(2U, offset);
+
+  DataExtractor BDE(StringRef(bigleb128data, sizeof(bigleb128data)-1), false,8);
+  offset = 0;
+  EXPECT_EQ(42218325750568106ULL, BDE.getULEB128(&offset));
+  EXPECT_EQ(8U, offset);
+  offset = 0;
+  EXPECT_EQ(-29839268287359830LL, BDE.getSLEB128(&offset));
+  EXPECT_EQ(8U, offset);
 }
 
 }