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::bad_header);
+
   CountersDelta = swap(Header.CountersDelta);
   NamesDelta = swap(Header.NamesDelta);
   auto DataSize = swap(Header.DataSize);
@@ -402,6 +405,10 @@
   NamesStart = Start + NamesOffset;
   ValueDataStart = reinterpret_cast<const uint8_t *>(Start + ValueDataOffset);
 
+  const uint8_t *BufferEnd = (const uint8_t *)DataBuffer->getBufferEnd();
+  if (BinaryIdsStart + BinaryIdsSize > BufferEnd)
+    return error(instrprof_error::bad_header);
+
   std::unique_ptr<InstrProfSymtab> NewSymtab = std::make_unique<InstrProfSymtab>();
   if (Error E = createSymtab(*NewSymtab.get()))
     return E;
@@ -520,6 +527,10 @@
   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 +538,21 @@
 
   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 +562,9 @@
       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);
   }
diff --git a/llvm/test/tools/llvm-profdata/binary-ids-padding.test b/llvm/test/tools/llvm-profdata/binary-ids-padding.test
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/llvm-profdata/binary-ids-padding.test
@@ -0,0 +1,72 @@
+// Header
+//
+// INSTR_PROF_RAW_HEADER(uint64_t, Magic, __llvm_profile_get_magic())
+// INSTR_PROF_RAW_HEADER(uint64_t, Version, __llvm_profile_get_version())
+// INSTR_PROF_RAW_HEADER(uint64_t, BinaryIdsSize, __llvm_write_binary_ids(NULL))
+// INSTR_PROF_RAW_HEADER(uint64_t, DataSize, DataSize)
+// INSTR_PROF_RAW_HEADER(uint64_t, CountersSize, CountersSize)
+// INSTR_PROF_RAW_HEADER(uint64_t, NamesSize,  NamesSize)
+// INSTR_PROF_RAW_HEADER(uint64_t, CountersDelta, (uintptr_t)CountersBegin)
+// INSTR_PROF_RAW_HEADER(uint64_t, NamesDelta, (uintptr_t)NamesBegin)
+// INSTR_PROF_RAW_HEADER(uint64_t, ValueKindLast, IPVK_Last)
+
+RUN: printf '\201rforpl\377' > %t.profraw
+RUN: printf '\7\0\0\0\0\0\0\0' >> %t.profraw
+// There will be 2 20-byte binary IDs, so the total Binary IDs size will be 64 bytes.
+//   2 * 8  binary ID sizes
+// + 2 * 20 binary IDs (of size 20)
+// + 2 * 4  binary ID paddings
+// --------
+// = 64     bytes
+RUN: printf '\100\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\2\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\3\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\20\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\4\0\1\0\0\0' >> %t.profraw
+RUN: printf '\0\0\4\0\2\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+
+// Binary IDs - There are only two in this case that are 20 bytes.
+RUN: printf '\24\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\1\2\3\4\5\6\7' >> %t.profraw
+RUN: printf '\0\1\2\3\4\5\6\7' >> %t.profraw
+RUN: printf '\0\1\2\3\0\0\0\0' >> %t.profraw
+RUN: printf '\24\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\1\1\1\1\1\1\1\1' >> %t.profraw
+RUN: printf '\2\2\2\2\2\2\2\2' >> %t.profraw
+RUN: printf '\3\3\3\3\0\0\0\0' >> %t.profraw
+
+// Data Section
+//
+// struct ProfData {
+// #define INSTR_PROF_DATA(Type, LLVMType, Name, Initializer) \
+//    Type Name;
+// #include "llvm/ProfileData/InstrProfData.inc"
+// };
+
+RUN: printf '\254\275\030\333\114\302\370\134' >> %t.profraw
+RUN: printf '\1\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\4\0\1\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\1\0\0\0\0\0\0\0' >> %t.profraw
+
+RUN: printf '\067\265\035\031\112\165\023\344' >> %t.profraw
+RUN: printf '\02\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\xd8\xff\3\0\1\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\02\0\0\0\0\0\0\0' >> %t.profraw
+
+RUN: printf '\023\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\067\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\101\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\7\0foo\1bar\0\0\0\0\0\0\0' >> %t.profraw
+
+// RUN: llvm-profdata show --binary-ids  %t.profraw | FileCheck %s
+// CHECK: Instrumentation level: Front-end
+// CHECK: Binary IDs:
+// CHECK-NEXT: 0001020304050607000102030405060700010203
+// CHECK-NEXT: 0101010101010101020202020202020203030303
diff --git a/llvm/test/tools/llvm-profdata/insufficient-binary-ids-size.test b/llvm/test/tools/llvm-profdata/insufficient-binary-ids-size.test
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/llvm-profdata/insufficient-binary-ids-size.test
@@ -0,0 +1,20 @@
+RUN: printf '\201rforpl\377' > %t.profraw
+RUN: printf '\7\0\0\0\0\0\0\0' >> %t.profraw
+// We should fail on this because the data buffer (profraw file) is not long
+// enough to hold this binary IDs size. NOTE that this (combined with the 8-byte
+// alignment requirement for binary IDs size) will ensure we can at least read one
+// 8-byte size if the binary IDs are provided.
+RUN: printf '\8\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+
+RUN: printf '\0\0\0\0\0\0\0' >> %t.profraw
+
+// RUN: not llvm-profdata show --binary-ids  %t.profraw 2>&1 | FileCheck %s
+// CHECK: invalid instrumentation profile data (file header is corrupt)
diff --git a/llvm/test/tools/llvm-profdata/large-binary-id-size.test b/llvm/test/tools/llvm-profdata/large-binary-id-size.test
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/llvm-profdata/large-binary-id-size.test
@@ -0,0 +1,20 @@
+RUN: printf '\201rforpl\377' > %t.profraw
+RUN: printf '\7\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\40\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+
+// Check for a corrupted size being too large past the end of the file.
+RUN: printf '\7\7\7\7\7\7\7\7' >> %t.profraw
+RUN: printf '\0\1\2\3\4\5\6\7' >> %t.profraw
+RUN: printf '\0\1\2\3\4\5\6\7' >> %t.profraw
+RUN: printf '\0\1\2\3\0\0\0\0' >> %t.profraw
+
+// RUN: not llvm-profdata show --binary-ids  %t.profraw 2>&1 | FileCheck %s
+// CHECK: malformed instrumentation profile data
diff --git a/llvm/test/tools/llvm-profdata/misaligned-binary-ids-size.test b/llvm/test/tools/llvm-profdata/misaligned-binary-ids-size.test
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/llvm-profdata/misaligned-binary-ids-size.test
@@ -0,0 +1,25 @@
+RUN: printf '\201rforpl\377' > %t.profraw
+RUN: printf '\7\0\0\0\0\0\0\0' >> %t.profraw
+// We should fail on this because the binary IDs is not a multiple of 8 bytes.
+RUN: printf '\77\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t.profraw
+
+// Binary IDs - There are only two in this case that are 20 bytes.
+RUN: printf '\24\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\0\1\2\3\4\5\6\7' >> %t.profraw
+RUN: printf '\0\1\2\3\4\5\6\7' >> %t.profraw
+RUN: printf '\0\1\2\3\0\0\0\0' >> %t.profraw
+RUN: printf '\24\0\0\0\0\0\0\0' >> %t.profraw
+RUN: printf '\1\1\1\1\1\1\1\1' >> %t.profraw
+RUN: printf '\2\2\2\2\2\2\2\2' >> %t.profraw
+RUN: printf '\3\3\3\3\0\0\0\0' >> %t.profraw
+
+// RUN: not llvm-profdata show --binary-ids  %t.profraw 2>&1 | FileCheck %s
+// CHECK: invalid instrumentation profile data (file header is corrupt)