diff --git a/compiler-rt/lib/profile/InstrProfilingPlatformLinux.c b/compiler-rt/lib/profile/InstrProfilingPlatformLinux.c
--- a/compiler-rt/lib/profile/InstrProfilingPlatformLinux.c
+++ b/compiler-rt/lib/profile/InstrProfilingPlatformLinux.c
@@ -95,10 +95,13 @@
  * have a fixed length.
  */
 static int WriteOneBinaryId(ProfDataWriter *Writer, uint64_t BinaryIdLen,
-                            const uint8_t *BinaryIdData) {
+                            const uint8_t *BinaryIdData,
+                            uint64_t BinaryIdPadding) {
   ProfDataIOVec BinaryIdIOVec[] = {
       {&BinaryIdLen, sizeof(uint64_t), 1, 0},
-      {BinaryIdData, sizeof(uint8_t), BinaryIdLen, 0}};
+      {BinaryIdData, sizeof(uint8_t), BinaryIdLen, 0},
+      {NULL, sizeof(uint8_t), BinaryIdPadding, 1},
+  };
   if (Writer->Write(Writer, BinaryIdIOVec,
                     sizeof(BinaryIdIOVec) / sizeof(*BinaryIdIOVec)))
     return -1;
@@ -130,11 +133,12 @@
     uint64_t BinaryIdLen = Note->n_descsz;
     const uint8_t *BinaryIdData =
         (const uint8_t *)(NoteName + RoundUp(Note->n_namesz, 4));
-    if (Writer != NULL &&
-        WriteOneBinaryId(Writer, BinaryIdLen, BinaryIdData) == -1)
+    uint8_t BinaryIdPadding = __llvm_profile_get_num_padding_bytes(BinaryIdLen);
+    if (Writer != NULL && WriteOneBinaryId(Writer, BinaryIdLen, BinaryIdData,
+                                           BinaryIdPadding) == -1)
       return -1;
 
-    BinaryIdSize = sizeof(BinaryIdLen) + BinaryIdLen;
+    BinaryIdSize = sizeof(BinaryIdLen) + BinaryIdLen + BinaryIdPadding;
   }
 
   return BinaryIdSize;
diff --git a/llvm/lib/ProfileData/InstrProfReader.cpp b/llvm/lib/ProfileData/InstrProfReader.cpp
--- a/llvm/lib/ProfileData/InstrProfReader.cpp
+++ b/llvm/lib/ProfileData/InstrProfReader.cpp
@@ -367,6 +367,9 @@
     return error(instrprof_error::unsupported_version);
 
   BinaryIdsSize = swap(Header.BinaryIdsSize);
+  if (BinaryIdsSize % sizeof(uint64_t))
+    return error(instrprof_error::malformed);
+
   CountersDelta = swap(Header.CountersDelta);
   NamesDelta = swap(Header.NamesDelta);
   auto DataSize = swap(Header.DataSize);
@@ -520,6 +523,10 @@
   return success();
 }
 
+static size_t RoundUp(size_t size, size_t align) {
+  return (size + align - 1) & ~(align - 1);
+}
+
 template <class IntPtrT>
 Error RawInstrProfReader<IntPtrT>::printBinaryIds(raw_ostream &OS) {
   if (BinaryIdsSize == 0)
@@ -527,8 +534,21 @@
 
   OS << "Binary IDs: \n";
   const uint8_t *BI = BinaryIdsStart;
-  while (BI < BinaryIdsStart + BinaryIdsSize) {
+  const uint8_t *BIEnd = BinaryIdsStart + BinaryIdsSize;
+  while (BI < BIEnd) {
+    size_t Remaining = BIEnd - BI;
+
+    // There should be enough left to read the binary ID size field.
+    if (Remaining < sizeof(uint64_t))
+      return make_error<InstrProfError>(instrprof_error::malformed);
+
     uint64_t BinaryIdLen = swap(*reinterpret_cast<const uint64_t *>(BI));
+
+    // There should be enough left to read the binary ID size field, and the
+    // binary ID.
+    if (Remaining < sizeof(BinaryIdLen) + BinaryIdLen)
+      return make_error<InstrProfError>(instrprof_error::malformed);
+
     // Increment by binary id length data type size.
     BI += sizeof(BinaryIdLen);
     if (BI > (const uint8_t *)DataBuffer->getBufferEnd())
@@ -538,8 +558,9 @@
       OS << format("%02x", BI[I]);
     OS << "\n";
 
-    // Increment by binary id data length.
-    BI += BinaryIdLen;
+    // Increment by binary id data length, rounded to the next 8 bytes. This
+    // accounts for the zero-padding after each build ID.
+    BI += RoundUp(BinaryIdLen, sizeof(uint64_t));
     if (BI > (const uint8_t *)DataBuffer->getBufferEnd())
       return make_error<InstrProfError>(instrprof_error::malformed);
   }