[compiler-rt] [llvm] [MemProf] Write out raw profile bytes in little endian. (PR #150375)
Snehasish Kumar via llvm-commits
llvm-commits at lists.llvm.org
Wed Jul 30 18:55:26 PDT 2025
https://github.com/snehasish updated https://github.com/llvm/llvm-project/pull/150375
>From d66f282ff103f1aeed7a73aa6cba3b0d257c48d6 Mon Sep 17 00:00:00 2001
From: Snehasish Kumar <snehasishk at google.com>
Date: Thu, 24 Jul 2025 06:10:55 +0000
Subject: [PATCH 1/3] Write out raw profile bytes in little endian.
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.
---
.../lib/memprof/memprof_rawprofile.cpp | 17 +++++----
llvm/lib/ProfileData/MemProfReader.cpp | 35 +++++++++++++++++--
2 files changed, 44 insertions(+), 8 deletions(-)
diff --git a/compiler-rt/lib/memprof/memprof_rawprofile.cpp b/compiler-rt/lib/memprof/memprof_rawprofile.cpp
index f909d78f5f36a..fbcfee3d655eb 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) {
+ Buffer[I] = Src[I];
+ }
+#if defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+ for (size_t i = 0; i < sizeof(T) / 2; ++i) {
+ std::swap(buffer[i], buffer[sizeof(T) - 1 - 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.
>From 69ccfd6931c806d86165c1cf3006c259c0c48066 Mon Sep 17 00:00:00 2001
From: Snehasish Kumar <snehasishk at google.com>
Date: Wed, 30 Jul 2025 00:35:20 +0000
Subject: [PATCH 2/3] Address comment
---
compiler-rt/lib/memprof/memprof_rawprofile.cpp | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/compiler-rt/lib/memprof/memprof_rawprofile.cpp b/compiler-rt/lib/memprof/memprof_rawprofile.cpp
index fbcfee3d655eb..bf04afa679c9c 100644
--- a/compiler-rt/lib/memprof/memprof_rawprofile.cpp
+++ b/compiler-rt/lib/memprof/memprof_rawprofile.cpp
@@ -22,13 +22,13 @@ namespace {
template <class T> char *WriteBytes(const T &Pod, char *Buffer) {
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) {
- Buffer[I] = Src[I];
- }
+
+ for (size_t I = 0; I < sizeof(T); ++I)
#if defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
- for (size_t i = 0; i < sizeof(T) / 2; ++i) {
- std::swap(buffer[i], buffer[sizeof(T) - 1 - i]);
- }
+ // 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);
}
>From a4b7a903578a776ec6c6fa38baaa6a3eb7a16756 Mon Sep 17 00:00:00 2001
From: Snehasish Kumar <snehasishk at google.com>
Date: Wed, 30 Jul 2025 00:40:40 +0000
Subject: [PATCH 3/3] Format.
---
compiler-rt/lib/memprof/memprof_rawprofile.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/compiler-rt/lib/memprof/memprof_rawprofile.cpp b/compiler-rt/lib/memprof/memprof_rawprofile.cpp
index bf04afa679c9c..f579e12b15d0a 100644
--- a/compiler-rt/lib/memprof/memprof_rawprofile.cpp
+++ b/compiler-rt/lib/memprof/memprof_rawprofile.cpp
@@ -25,7 +25,7 @@ template <class T> char *WriteBytes(const T &Pod, char *Buffer) {
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.
+ // Reverse byte order since reader is little-endian.
Buffer[I] = Src[sizeof(T) - 1 - I];
#else
Buffer[I] = Src[I];
More information about the llvm-commits
mailing list