[llvm] [memprof] Make HeapProfileRecords optional (PR #155671)

[Kazu Hirata via llvm-commits]

https://github.com/kazutakahirata updated https://github.com/llvm/llvm-project/pull/155671

>From f4650c962a227d010e20ab78ef4bfb55d7178396 Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Wed, 27 Aug 2025 10:43:07 -0700
Subject: [PATCH 1/2] [memprof] Make HeapProfileRecords optional

memprof::AllMemProfData has become home to multiple types of memprof
data -- heap profile and static data profile.  When we write test
cases for static data profile in YAML, we do not want to include empty
heap profile.  That would just add visual clutter.

This patch makes HeapProfileRecords optional.
---
 llvm/include/llvm/ProfileData/MemProfYAML.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/llvm/include/llvm/ProfileData/MemProfYAML.h b/llvm/include/llvm/ProfileData/MemProfYAML.h
index ad5d7c0e22751..87e2f0ea14487 100644
--- a/llvm/include/llvm/ProfileData/MemProfYAML.h
+++ b/llvm/include/llvm/ProfileData/MemProfYAML.h
@@ -263,7 +263,8 @@ template <> struct MappingTraits<memprof::YamlDataAccessProfData> {
 
 template <> struct MappingTraits<memprof::AllMemProfData> {
   static void mapping(IO &Io, memprof::AllMemProfData &Data) {
-    Io.mapRequired("HeapProfileRecords", Data.HeapProfileRecords);
+    if (!Io.outputting() || !Data.HeapProfileRecords.empty())
+      Io.mapOptional("HeapProfileRecords", Data.HeapProfileRecords);
     // Map data access profiles if reading input, or if writing output &&
     // the struct is populated.
     if (!Io.outputting() || !Data.YamlifiedDataAccessProfiles.isEmpty())

>From 1040cdd6e0efa56fc1ad5c764c39c604360a3a95 Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Wed, 27 Aug 2025 12:30:50 -0700
Subject: [PATCH 2/2] Address a comment.

---
 .../include/llvm/ProfileData/DataAccessProf.h |  4 +++
 .../tools/llvm-profdata/memprof-yaml.test     | 34 +++++++++++++++++++
 llvm/tools/llvm-profdata/llvm-profdata.cpp    |  3 +-
 3 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/llvm/include/llvm/ProfileData/DataAccessProf.h b/llvm/include/llvm/ProfileData/DataAccessProf.h
index f410096d83f5e..7065689d544d4 100644
--- a/llvm/include/llvm/ProfileData/DataAccessProf.h
+++ b/llvm/include/llvm/ProfileData/DataAccessProf.h
@@ -185,6 +185,10 @@ class DataAccessProfData {
   ArrayRef<uint64_t> getKnownColdHashes() const {
     return KnownColdHashes.getArrayRef();
   }
+  [[nodiscard]] bool empty() const {
+    return Records.empty() && KnownColdSymbols.empty() &&
+           KnownColdHashes.empty();
+  }
 
 private:
   /// Serialize the symbol strings into the output stream.
diff --git a/llvm/test/tools/llvm-profdata/memprof-yaml.test b/llvm/test/tools/llvm-profdata/memprof-yaml.test
index 2e52b796ceedc..18b073c44531b 100644
--- a/llvm/test/tools/llvm-profdata/memprof-yaml.test
+++ b/llvm/test/tools/llvm-profdata/memprof-yaml.test
@@ -18,6 +18,11 @@
 ; RUN: llvm-profdata show --memory %t/memprof-out.indexed > %t/memprof-out-no-dap.yaml
 ; RUN: diff -b %t/memprof-in-no-dap.yaml %t/memprof-out-no-dap.yaml
 
+; memprof-in-no-heap.yaml has empty heap access profiles.
+; RUN: llvm-profdata merge --memprof-version=4 %t/memprof-in-no-heap.yaml -o %t/memprof-out-no-heap.indexed
+; RUN: llvm-profdata show --memory %t/memprof-out-no-heap.indexed > %t/memprof-out-no-heap.yaml
+; RUN: diff -b %t/memprof-in-no-heap.yaml %t/memprof-out-no-heap.yaml
+
 ;--- memprof-in.yaml
 ---
 # MemProfSummary:
@@ -151,3 +156,32 @@ HeapProfileRecords:
         - { Function: 0x8888888888888888, LineOffset: 88, Column: 80, IsInlineFrame: false }
         CalleeGuids: [ 0x300 ]
 ...
+;--- memprof-in-no-heap.yaml
+---
+# MemProfSummary:
+#   Total contexts: 0
+#   Total cold contexts: 0
+#   Total hot contexts: 0
+#   Maximum cold context total size: 0
+#   Maximum warm context total size: 0
+#   Maximum hot context total size: 0
+---
+DataAccessProfiles:
+  SampledRecords:
+    - Symbol:          abcde
+      AccessCount:     100
+      Locations:
+      - FileName:      file2.h
+        Line:          123
+      - FileName:      file3.cpp
+        Line:          456
+    - Hash:            101010
+      AccessCount:     200
+      Locations:
+        - FileName:        file.cpp
+          Line:            233
+  KnownColdSymbols:
+    - foo
+    - bar
+  KnownColdStrHashes: [ 999, 1001 ]
+...
diff --git a/llvm/tools/llvm-profdata/llvm-profdata.cpp b/llvm/tools/llvm-profdata/llvm-profdata.cpp
index 8fe0887c59774..d658ea99ab1b9 100644
--- a/llvm/tools/llvm-profdata/llvm-profdata.cpp
+++ b/llvm/tools/llvm-profdata/llvm-profdata.cpp
@@ -760,7 +760,8 @@ loadInput(const WeightedFile &Input, SymbolRemapper *Remapper,
     auto DataAccessProfData = Reader->takeDataAccessProfData();
 
     // Check for the empty input in case the YAML file is invalid.
-    if (MemProfData.Records.empty()) {
+    if (MemProfData.Records.empty() &&
+        (!DataAccessProfData || DataAccessProfData->empty())) {
       WC->Errors.emplace_back(
           make_error<StringError>("The profile is empty.", std::error_code()),
           Filename);