[profiling] Improve error message for raw profile header mismatches

When a user uses a mismatched clang + llvm-profdata, they didn't get a very
informative error message. It would just say "unsupported version".

As a result, users are often confused as to what they are supposed to do and
tend to assume that it's a bug in the profiling runtime.

This patch improves the error message by:

- Adding a new class of error (`raw_profile_version_mismatch`) to make it clear
  that, specifically, the *raw profile* version is unsupported because of a
  tool mismatch.

- Adding an error message that tells the user which raw profile version was
  encountered, which version was expected, and instructs them to align their
  tool versions.

To support this, this patch also updates `InstrProfError::take` to also
propagate the optional error message.

Differential Revision: https://reviews.llvm.org/D149361

diff --git a/clang/lib/CodeGen/CodeGenPGO.cpp b/clang/lib/CodeGen/CodeGenPGO.cpp
index 15a3d74..b803175 100644 (file)
--- a/clang/lib/CodeGen/CodeGenPGO.cpp
+++ b/clang/lib/CodeGen/CodeGenPGO.cpp
@@ -1036,7 +1036,7 @@ void CodeGenPGO::loadRegionCounts(llvm::IndexedInstrProfReader *PGOReader,
   llvm::Expected<llvm::InstrProfRecord> RecordExpected =
       PGOReader->getInstrProfRecord(FuncName, FunctionHash);
   if (auto E = RecordExpected.takeError()) {
-    auto IPE = llvm::InstrProfError::take(std::move(E));
+    auto IPE = std::get<0>(llvm::InstrProfError::take(std::move(E)));
     if (IPE == llvm::instrprof_error::unknown_function)
       CGM.getPGOStats().addMissing(IsInMainFile);
     else if (IPE == llvm::instrprof_error::hash_mismatch)

diff --git a/llvm/include/llvm/ProfileData/InstrProf.h b/llvm/include/llvm/ProfileData/InstrProf.h
index 2a9da23..ef01070 100644 (file)
--- a/llvm/include/llvm/ProfileData/InstrProf.h
+++ b/llvm/include/llvm/ProfileData/InstrProf.h
@@ -330,7 +330,8 @@ enum class instrprof_error {
   compress_failed,
   uncompress_failed,
   empty_raw_profile,
-  zlib_unavailable
+  zlib_unavailable,
+  raw_profile_version_mismatch
 };
 
 /// An ordered list of functions identified by their NameRef found in
@@ -362,15 +363,18 @@ public:
   instrprof_error get() const { return Err; }
   const std::string &getMessage() const { return Msg; }
 
-  /// Consume an Error and return the raw enum value contained within it. The
-  /// Error must either be a success value, or contain a single InstrProfError.
-  static instrprof_error take(Error E) {
+  /// Consume an Error and return the raw enum value contained within it, and
+  /// the optional error message. The Error must either be a success value, or
+  /// contain a single InstrProfError.
+  static std::pair<instrprof_error, std::string> take(Error E) {
     auto Err = instrprof_error::success;
-    handleAllErrors(std::move(E), [&Err](const InstrProfError &IPE) {
+    std::string Msg = "";
+    handleAllErrors(std::move(E), [&Err, &Msg](const InstrProfError &IPE) {
       assert(Err == instrprof_error::success && "Multiple errors encountered");
       Err = IPE.get();
+      Msg = IPE.getMessage();
     });
-    return Err;
+    return {Err, Msg};
   }
 
   static char ID;

diff --git a/llvm/lib/ProfileData/Coverage/CoverageMapping.cpp b/llvm/lib/ProfileData/Coverage/CoverageMapping.cpp
index d6aec27..849ee80 100644 (file)
--- a/llvm/lib/ProfileData/Coverage/CoverageMapping.cpp
+++ b/llvm/lib/ProfileData/Coverage/CoverageMapping.cpp
@@ -249,7 +249,7 @@ Error CoverageMapping::loadFunctionRecord(
   std::vector<uint64_t> Counts;
   if (Error E = ProfileReader.getFunctionCounts(Record.FunctionName,
                                                 Record.FunctionHash, Counts)) {
-    instrprof_error IPE = InstrProfError::take(std::move(E));
+    instrprof_error IPE = std::get<0>(InstrProfError::take(std::move(E)));
     if (IPE == instrprof_error::hash_mismatch) {
       FuncHashMismatches.emplace_back(std::string(Record.FunctionName),
                                       Record.FunctionHash);

diff --git a/llvm/lib/ProfileData/InstrProf.cpp b/llvm/lib/ProfileData/InstrProf.cpp
index d8dbcf1..1dd1ce4 100644 (file)
--- a/llvm/lib/ProfileData/InstrProf.cpp
+++ b/llvm/lib/ProfileData/InstrProf.cpp
@@ -153,6 +153,9 @@ static std::string getInstrProfErrString(instrprof_error Err,
     OS << "profile uses zlib compression but the profile reader was built "
           "without zlib support";
     break;
+  case instrprof_error::raw_profile_version_mismatch:
+    OS << "raw profile version mismatch";
+    break;
   }
 
   // If optional error message is not empty, append it to the message.

diff --git a/llvm/lib/ProfileData/InstrProfReader.cpp b/llvm/lib/ProfileData/InstrProfReader.cpp
index 47c0a57..4160f7e 100644 (file)
--- a/llvm/lib/ProfileData/InstrProfReader.cpp
+++ b/llvm/lib/ProfileData/InstrProfReader.cpp
@@ -532,7 +532,13 @@ Error RawInstrProfReader<IntPtrT>::readHeader(
     const RawInstrProf::Header &Header) {
   Version = swap(Header.Version);
   if (GET_VERSION(Version) != RawInstrProf::Version)
-    return error(instrprof_error::unsupported_version);
+    return error(instrprof_error::raw_profile_version_mismatch,
+                 ("Profile uses raw profile format version = " +
+                  Twine(GET_VERSION(Version)) +
+                  "; expected version = " + Twine(RawInstrProf::Version) +
+                  "\nPLEASE update this tool to version in the raw profile, or "
+                  "regenerate raw profile with expected version.")
+                     .str());
   if (useDebugInfoCorrelate() && !Correlator)
     return error(instrprof_error::missing_debug_info_for_correlation);
   if (!useDebugInfoCorrelate() && Correlator)
@@ -1199,7 +1205,8 @@ InstrProfSymtab &IndexedInstrProfReader::getSymtab() {
 
   std::unique_ptr<InstrProfSymtab> NewSymtab = std::make_unique<InstrProfSymtab>();
   if (Error E = Index->populateSymtab(*NewSymtab)) {
-    consumeError(error(InstrProfError::take(std::move(E))));
+    auto [ErrCode, Msg] = InstrProfError::take(std::move(E));
+    consumeError(error(ErrCode, Msg));
   }
 
   Symtab = std::move(NewSymtab);

diff --git a/llvm/test/tools/llvm-profdata/mismatched-raw-profile-header.test b/llvm/test/tools/llvm-profdata/mismatched-raw-profile-header.test
new file mode 100644 (file)
index 0000000..24f3f56
--- /dev/null
+++ b/llvm/test/tools/llvm-profdata/mismatched-raw-profile-header.test
@@ -0,0 +1,19 @@
+// Magic
+RUN: printf '\377lprofr\201' > %t
+// Version
+RUN: printf '\0\01\0\0\0\0\0\10' >> %t
+// The rest of the header needs to be there to prevent a broken header error.
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t
+RUN: printf '\0\0\0\0\0\0\0\2' >> %t
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t
+RUN: printf '\0\0\0\0\0\0\0\3' >> %t
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t
+RUN: printf '\0\0\0\0\0\0\0\20' >> %t
+RUN: printf '\0\0\0\1\0\4\0\0' >> %t
+RUN: printf '\0\0\0\2\0\4\0\0' >> %t
+RUN: printf '\0\0\0\0\0\0\0\0' >> %t
+
+RUN: not llvm-profdata show %t -o /dev/null 2>&1 | FileCheck %s
+
+CHECK: raw profile version mismatch: Profile uses raw profile format version = 281474976710664; expected version = {{[0-9]+}}
+CHECK-NEXT: PLEASE update this tool to version in the raw profile, or regenerate raw profile with expected version.

diff --git a/llvm/tools/llvm-profdata/llvm-profdata.cpp b/llvm/tools/llvm-profdata/llvm-profdata.cpp
index 3db5479..e14bfd8 100644 (file)
--- a/llvm/tools/llvm-profdata/llvm-profdata.cpp
+++ b/llvm/tools/llvm-profdata/llvm-profdata.cpp
@@ -233,9 +233,10 @@ static void overlapInput(const std::string &BaseFilename,
   auto ReaderOrErr = InstrProfReader::create(TestFilename, *FS);
   if (Error E = ReaderOrErr.takeError()) {
     // Skip the empty profiles by returning sliently.
-    instrprof_error IPE = InstrProfError::take(std::move(E));
-    if (IPE != instrprof_error::empty_raw_profile)
-      WC->Errors.emplace_back(make_error<InstrProfError>(IPE), TestFilename);
+    auto [ErrorCode, Msg] = InstrProfError::take(std::move(E));
+    if (ErrorCode != instrprof_error::empty_raw_profile)
+      WC->Errors.emplace_back(make_error<InstrProfError>(ErrorCode, Msg),
+                              TestFilename);
     return;
   }
 
@@ -280,8 +281,9 @@ static void loadInput(const WeightedFile &Input, SymbolRemapper *Remapper,
     }
 
     auto MemProfError = [&](Error E) {
-      instrprof_error IPE = InstrProfError::take(std::move(E));
-      WC->Errors.emplace_back(make_error<InstrProfError>(IPE), Filename);
+      auto [ErrorCode, Msg] = InstrProfError::take(std::move(E));
+      WC->Errors.emplace_back(make_error<InstrProfError>(ErrorCode, Msg),
+                              Filename);
     };
 
     // Add the frame mappings into the writer context.
@@ -306,9 +308,10 @@ static void loadInput(const WeightedFile &Input, SymbolRemapper *Remapper,
   auto ReaderOrErr = InstrProfReader::create(Input.Filename, *FS, Correlator);
   if (Error E = ReaderOrErr.takeError()) {
     // Skip the empty profiles by returning silently.
-    instrprof_error IPE = InstrProfError::take(std::move(E));
-    if (IPE != instrprof_error::empty_raw_profile)
-      WC->Errors.emplace_back(make_error<InstrProfError>(IPE), Filename);
+    auto [ErrCode, Msg] = InstrProfError::take(std::move(E));
+    if (ErrCode != instrprof_error::empty_raw_profile)
+      WC->Errors.emplace_back(make_error<InstrProfError>(ErrCode, Msg),
+                              Filename);
     return;
   }
 
@@ -335,11 +338,11 @@ static void loadInput(const WeightedFile &Input, SymbolRemapper *Remapper,
       }
       Reported = true;
       // Only show hint the first time an error occurs.
-      instrprof_error IPE = InstrProfError::take(std::move(E));
+      auto [ErrCode, Msg] = InstrProfError::take(std::move(E));
       std::unique_lock<std::mutex> ErrGuard{WC->ErrLock};
-      bool firstTime = WC->WriterErrorCodes.insert(IPE).second;
-      handleMergeWriterError(make_error<InstrProfError>(IPE), Input.Filename,
-                             FuncName, firstTime);
+      bool firstTime = WC->WriterErrorCodes.insert(ErrCode).second;
+      handleMergeWriterError(make_error<InstrProfError>(ErrCode, Msg),
+                             Input.Filename, FuncName, firstTime);
     });
   }
 
@@ -370,11 +373,11 @@ static void mergeWriterContexts(WriterContext *Dst, WriterContext *Src) {
     exitWithError(std::move(E));
 
   Dst->Writer.mergeRecordsFromWriter(std::move(Src->Writer), [&](Error E) {
-    instrprof_error IPE = InstrProfError::take(std::move(E));
+    auto [ErrorCode, Msg] = InstrProfError::take(std::move(E));
     std::unique_lock<std::mutex> ErrGuard{Dst->ErrLock};
-    bool firstTime = Dst->WriterErrorCodes.insert(IPE).second;
+    bool firstTime = Dst->WriterErrorCodes.insert(ErrorCode).second;
     if (firstTime)
-      warn(toString(make_error<InstrProfError>(IPE)));
+      warn(toString(make_error<InstrProfError>(ErrorCode, Msg)));
   });
 }
 

diff --git a/llvm/unittests/ProfileData/InstrProfTest.cpp b/llvm/unittests/ProfileData/InstrProfTest.cpp
index 3ed2176..d7b9d73 100644 (file)
--- a/llvm/unittests/ProfileData/InstrProfTest.cpp
+++ b/llvm/unittests/ProfileData/InstrProfTest.cpp
@@ -869,7 +869,9 @@ TEST_P(MaybeSparseInstrProfTest, get_icall_data_merge1_saturation) {
   const uint64_t MaxEdgeCount = getInstrMaxCountValue();
 
   instrprof_error Result;
-  auto Err = [&](Error E) { Result = InstrProfError::take(std::move(E)); };
+  auto Err = [&](Error E) {
+    Result = std::get<0>(InstrProfError::take(std::move(E)));
+  };
   Result = instrprof_error::success;
   Writer.addRecord({"foo", 0x1234, {1}}, Err);
   ASSERT_EQ(Result, instrprof_error::success);