[MemProf] Write out raw profile bytes in little endian. (#150375)

Instead of writing out in native endian, write out the raw profile bytes
in little endian. Also update the MIB data in little endian. Also clean
up some lint and unused includes in rawprofile.cpp.

Author: snehasish

compiler-rt/lib/memprof/memprof_rawprofile.cpp

@@ -7,10 +7,7 @@
 #include "sanitizer_common/sanitizer_allocator_internal.h"
 #include "sanitizer_common/sanitizer_array_ref.h"
 #include "sanitizer_common/sanitizer_common.h"
-#include "sanitizer_common/sanitizer_linux.h"
-#include "sanitizer_common/sanitizer_procmaps.h"
 #include "sanitizer_common/sanitizer_stackdepot.h"
-#include "sanitizer_common/sanitizer_stackdepotbase.h"
 #include "sanitizer_common/sanitizer_stacktrace.h"
 #include "sanitizer_common/sanitizer_vector.h"
 
@@ -23,7 +20,16 @@ using ::llvm::memprof::encodeHistogramCount;
 
 namespace {
 template <class T> char *WriteBytes(const T &Pod, char *Buffer) {
-  *(T *)Buffer = Pod;
+  static_assert(is_trivially_copyable<T>::value, "T must be POD");
+  const uint8_t *Src = reinterpret_cast<const uint8_t *>(&Pod);
+
+  for (size_t I = 0; I < sizeof(T); ++I)
+#if defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+    // Reverse byte order since reader is little-endian.
+    Buffer[I] = Src[sizeof(T) - 1 - I];
+#else
+    Buffer[I] = Src[I];
+#endif
   return Buffer + sizeof(T);
 }
 
@@ -33,7 +39,6 @@ void RecordStackId(const uptr Key, UNUSED LockedMemInfoBlock *const &MIB,
   auto *StackIds = reinterpret_cast<Vector<u64> *>(Arg);
   StackIds->PushBack(Key);
 }
-} // namespace
 
 u64 SegmentSizeBytes(ArrayRef<LoadedModule> Modules) {
   u64 NumSegmentsToRecord = 0;
@@ -184,6 +189,7 @@ void SerializeMIBInfoToBuffer(MIBMapTy &MIBMap, const Vector<u64> &StackIds,
   CHECK(ExpectedNumBytes >= static_cast<u64>(Ptr - Buffer) &&
         "Expected num bytes != actual bytes written");
 }
+} // namespace
 
 // Format
 // ---------- Header
@@ -288,5 +294,4 @@ u64 SerializeToRawProfile(MIBMapTy &MIBMap, ArrayRef<LoadedModule> Modules,
 
   return TotalSizeBytes;
 }
-
 } // namespace __memprof

llvm/lib/ProfileData/MemProfReader.cpp

@@ -146,8 +146,39 @@ readMemInfoBlocksCommon(const char *Ptr, bool IsHistogramEncoded = false) {
     const uint64_t Id =
         endian::readNext<uint64_t, llvm::endianness::little, unaligned>(Ptr);
 
-    MemInfoBlock MIB = *reinterpret_cast<const MemInfoBlock *>(Ptr);
-    Ptr += sizeof(MemInfoBlock);
+    MemInfoBlock MIB;
+#define READ_MIB_FIELD(FIELD)                                                  \
+  MIB.FIELD = endian::readNext<decltype(MIB.FIELD), llvm::endianness::little,  \
+                               unaligned>(Ptr)
+
+    READ_MIB_FIELD(AllocCount);
+    READ_MIB_FIELD(TotalAccessCount);
+    READ_MIB_FIELD(MinAccessCount);
+    READ_MIB_FIELD(MaxAccessCount);
+    READ_MIB_FIELD(TotalSize);
+    READ_MIB_FIELD(MinSize);
+    READ_MIB_FIELD(MaxSize);
+    READ_MIB_FIELD(AllocTimestamp);
+    READ_MIB_FIELD(DeallocTimestamp);
+    READ_MIB_FIELD(TotalLifetime);
+    READ_MIB_FIELD(MinLifetime);
+    READ_MIB_FIELD(MaxLifetime);
+    READ_MIB_FIELD(AllocCpuId);
+    READ_MIB_FIELD(DeallocCpuId);
+    READ_MIB_FIELD(NumMigratedCpu);
+    READ_MIB_FIELD(NumLifetimeOverlaps);
+    READ_MIB_FIELD(NumSameAllocCpu);
+    READ_MIB_FIELD(NumSameDeallocCpu);
+    READ_MIB_FIELD(DataTypeId);
+    READ_MIB_FIELD(TotalAccessDensity);
+    READ_MIB_FIELD(MinAccessDensity);
+    READ_MIB_FIELD(MaxAccessDensity);
+    READ_MIB_FIELD(TotalLifetimeAccessDensity);
+    READ_MIB_FIELD(MinLifetimeAccessDensity);
+    READ_MIB_FIELD(MaxLifetimeAccessDensity);
+    READ_MIB_FIELD(AccessHistogramSize);
+    READ_MIB_FIELD(AccessHistogram);
+#undef READ_MIB_FIELD
 
     if (MIB.AccessHistogramSize > 0) {
       // The in-memory representation uses uint64_t for histogram entries.