Add CtxSplitLayout support for text mode (for manual inspection only)

Fixed wordings refering to this flag, Previously it is described as
"samples with/out context", which confuses with CSSPGO. Now they are
called "samples/functions with/out inlined functions"

Author: huangjd

llvm/docs/CommandGuide/llvm-profdata.rst

@@ -162,7 +162,7 @@ OPTIONS
  coverage for the optimized target. This option can only be used with
  sample-based profile in extbinary format.
 
-.. option:: --split_layout=[true|false]
+.. option:: --split-layout=[true|false]
 
  Split the profile data section to two with one containing sample profiles with
  inlined functions and the other not. This option can only be used with

llvm/include/llvm/ProfileData/SampleProfWriter.h

@@ -28,9 +28,9 @@ namespace sampleprof {
 
 enum SectionLayout {
   DefaultLayout,
-  // The layout splits profile with context information from profile without
-  // context information. When Thinlto is enabled, ThinLTO postlink phase only
-  // has to load profile with context information and can skip the other part.
+  // The layout splits profile with inlined functions from profile without
+  // inlined functions. When Thinlto is enabled, ThinLTO postlink phase only
+  // has to load profile with inlined functions and can skip the other part.
   CtxSplitLayout,
   NumOfLayout,
 };
@@ -128,7 +128,7 @@ class SampleProfileWriter {
   virtual void setToCompressAllSections() {}
   virtual void setUseMD5() {}
   virtual void setPartialProfile() {}
-  virtual void resetSecLayout(SectionLayout SL) {}
+  virtual void setUseCtxSplitLayout() {}
 
 protected:
   SampleProfileWriter(std::unique_ptr<raw_ostream> &OS)
@@ -176,12 +176,22 @@ class SampleProfileWriterText : public SampleProfileWriter {
     return sampleprof_error::success;
   }
 
+  void setUseCtxSplitLayout() override {
+    MarkFlatProfiles = true;
+  }
+
 private:
   /// Indent level to use when writing.
   ///
   /// This is used when printing inlined callees.
   unsigned Indent = 0;
 
+  /// If set, writes metadata "!Flat" to functions without inlined functions.
+  /// This flag is for manual inspection only, it has no effect for the profile
+  /// reader because a text sample profile is read sequentially and functions
+  /// cannot be skipped.
+  bool MarkFlatProfiles = false;
+
   friend ErrorOr<std::unique_ptr<SampleProfileWriter>>
   SampleProfileWriter::create(std::unique_ptr<raw_ostream> &OS,
                               SampleProfileFormat Format);
@@ -242,11 +252,11 @@ const std::array<SmallVector<SecHdrTableEntry, 8>, NumOfLayout>
         // CtxSplitLayout
         SmallVector<SecHdrTableEntry, 8>({{SecProfSummary, 0, 0, 0, 0},
                                           {SecNameTable, 0, 0, 0, 0},
-                                          // profile with context
+                                          // profile with inlined functions
                                           // for next two sections
                                           {SecFuncOffsetTable, 0, 0, 0, 0},
                                           {SecLBRProfile, 0, 0, 0, 0},
-                                          // profile without context
+                                          // profile without inlined functions
                                           // for next two sections
                                           {SecFuncOffsetTable, 0, 0, 0, 0},
                                           {SecLBRProfile, 0, 0, 0, 0},
@@ -283,7 +293,11 @@ class SampleProfileWriterExtBinaryBase : public SampleProfileWriterBinary {
     ProfSymList = PSL;
   };
 
-  void resetSecLayout(SectionLayout SL) override {
+  void setUseCtxSplitLayout() override {
+    resetSecLayout(SectionLayout::CtxSplitLayout);
+  }
+
+  void resetSecLayout(SectionLayout SL) {
     verifySecLayout(SL);
 #ifndef NDEBUG
     // Make sure resetSecLayout is called before any flag setting.

llvm/lib/ProfileData/SampleProfReader.cpp

@@ -223,6 +223,11 @@ static bool ParseLine(const StringRef &Input, LineType &LineTy, uint32_t &Depth,
 
   if (Input[Depth] == '!') {
     LineTy = LineType::Metadata;
+    // This metadata is only for manual inspection only. We already created a
+    // FunctionSamples and put it in the profile map, so there is no point
+    // to skip profiles even they have no use for ThinLTO.
+    if (Input == StringRef(" !Flat"))
+      return true;
     return parseMetadata(Input.substr(Depth), FunctionHash, Attributes);
   }
 
@@ -1026,7 +1031,7 @@ std::error_code SampleProfileReaderExtBinaryBase::readImpl() {
     if (!Entry.Size)
       continue;
 
-    // Skip sections without context when SkipFlatProf is true.
+    // Skip sections without inlined functions when SkipFlatProf is true.
     if (SkipFlatProf && hasSecFlag(Entry, SecCommonFlags::SecFlagFlat))
       continue;
 

llvm/lib/ProfileData/SampleProfWriter.cpp

@@ -624,6 +624,9 @@ std::error_code SampleProfileWriterText::writeSample(const FunctionSamples &S) {
     LineCount++;
   }
 
+  if (Indent == 0 && MarkFlatProfiles && S.getCallsiteSamples().size() == 0)
+    OS << " !Flat\n";
+
   return sampleprof_error::success;
 }
 

llvm/test/tools/llvm-profdata/sample-split-layout.test

@@ -1,2 +1,22 @@
-RUN: llvm-profdata merge --sample --extbinary --split_layout %p/Inputs/sample-profile.proftext -o %t-output
+RUN: llvm-profdata merge --sample --extbinary --split-layout %p/Inputs/sample-profile.proftext -o %t-output
 RUN: diff %t-output %p/Inputs/split-layout.profdata
+
+RUN: llvm-profdata merge --sample --text --split-layout %t-output | FileCheck %s
+CHECK: main:184019:0
+CHECK-NEXT:  4: 534
+CHECK-NEXT:  4.2: 534
+CHECK-NEXT:  5: 1075
+CHECK-NEXT:  5.1: 1075
+CHECK-NEXT:  6: 2080
+CHECK-NEXT:  7: 534
+CHECK-NEXT:  9: 2064 _Z3bari:1471 _Z3fooi:631
+CHECK-NEXT:  10: inline1:1000
+CHECK-NEXT:   1: 1000
+CHECK-NEXT:  10: inline2:2000
+CHECK-NEXT:   1: 2000
+CHECK-NEXT: _Z3bari:20301:1437
+CHECK-NEXT:  1: 1437
+CHECK-NEXT:  !Flat
+CHECK-NEXT: _Z3fooi:7711:610
+CHECK-NEXT:  1: 610
+CHECK-NEXT:  !Flat

llvm/tools/llvm-profdata/llvm-profdata.cpp

@@ -208,10 +208,10 @@ cl::opt<bool> GenPartialProfile(
     cl::sub(MergeSubcommand),
     cl::desc("Generate a partial profile (only meaningful for -extbinary)"));
 cl::opt<bool> SplitLayout(
-    "split_layout", cl::init(false), cl::Hidden,
+    "split-layout", cl::init(false), cl::Hidden,
     cl::sub(MergeSubcommand),
     cl::desc("Split the profile to two sections with one containing sample "
-             "profiles with inlined functions and the another not (only "
+             "profiles with inlined functions and the other without (only "
              "meaningful for -extbinary)"));
 cl::opt<std::string> SupplInstrWithSample(
     "supplement-instr-with-sample", cl::init(""), cl::Hidden,
@@ -1473,6 +1473,13 @@ static void handleExtBinaryWriter(sampleprof::SampleProfileWriter &Writer,
                                   sampleprof::ProfileSymbolList &WriterList,
                                   bool CompressAllSections, bool UseMD5,
                                   bool GenPartialProfile) {
+  if (SplitLayout) {
+    if (OutputFormat == PF_Binary)
+      warn("-split-layout is ignored. Specify -extbinary to enable it");
+    else
+      Writer.setUseCtxSplitLayout();
+  }
+
   populateProfileSymbolList(Buffer, WriterList);
   if (WriterList.size() > 0 && OutputFormat != PF_Ext_Binary)
     warn("Profile Symbol list is not empty but the output format is not "
@@ -1498,12 +1505,6 @@ static void handleExtBinaryWriter(sampleprof::SampleProfileWriter &Writer,
     else
       Writer.setPartialProfile();
   }
-  if (SplitLayout) {
-    if (OutputFormat != PF_Ext_Binary)
-      warn("-split-layout is ignored. Specify -extbinary to enable it");
-    else
-      Writer.resetSecLayout(SectionLayout::CtxSplitLayout);
-  }
 }
 
 static void mergeSampleProfile(const WeightedFileVector &Inputs,