[MemProf] Write out raw profile bytes in little endian.

[snehasish]

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.

[snehasish]

• [MemProf] Fix FileCheck prefix in the histogram test. #150506
• [MemProf] Write out raw profile bytes in little endian. #150375 👈 (View in Graphite)
• [MemProf] Change histogram storage from uint64_t to uint16_t #147854
• main

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[teresajohnson]

buffer should be Buffer?

[teresajohnson]

alternatively, copy in from Src above in the current direction if little endian, and in reverse order if big endian (rather than copy and swap in the BE case)?

[snehasish]

Done.

[snehasish]

Ptal, thanks.

[snehasish]

Done.

[llvmbot]

@llvm/pr-subscribers-pgo

Author: Snehasish Kumar (snehasish)

Changes

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.

---

Full diff: https://github.com/llvm/llvm-project/pull/150375.diff

2 Files Affected:

• (modified) compiler-rt/lib/memprof/memprof_rawprofile.cpp (+11-6)
• (modified) llvm/lib/ProfileData/MemProfReader.cpp (+33-2)

diff --git a/compiler-rt/lib/memprof/memprof_rawprofile.cpp b/compiler-rt/lib/memprof/memprof_rawprofile.cpp
index f909d78f5f36a..bf04afa679c9c 100644
--- a/compiler-rt/lib/memprof/memprof_rawprofile.cpp
+++ b/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
diff --git a/llvm/lib/ProfileData/MemProfReader.cpp b/llvm/lib/ProfileData/MemProfReader.cpp
index 9db699712d6f3..3fc0dbfd8e69d 100644
--- a/llvm/lib/ProfileData/MemProfReader.cpp
+++ b/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.

[github-actions]

✅ With the latest revision this PR passed the C/C++ code formatter.

[teresajohnson]

lgtm but suggest updating the title and/or description to note this is for MemProf.