[InstrProf] Emit warnings when correlating lightweight profiles

Emit warnings when `InstrProfCorrelator` finds problems with debug info for lightweight instrumentation profile correlation. To prevent excessive printing, only emit the first 5 warnings.

In addition, remove a diagnostic about missing debug info in `InstrProfiling.cpp`. Some compiler-generated functions, e.g., `__clang_call_terminate`, does not emit debug info and will fail a build if `-Werror` is used. This warning is not actionable by the user and I have not seen non-compiler-generated functions fail this test.

Reviewed By: smeenai

Differential Revision: https://reviews.llvm.org/D156006

Author: ellishg

compiler-rt/test/profile/Linux/instrprof-debug-info-correlate-warnings.c

@@ -0,0 +1,13 @@
+// Disable full debug info and verify that we get warnings during merging
+
+// RUN: %clang_pgogen -o %t -gline-tables-only -mllvm --debug-info-correlate -mllvm --disable-vp=true %S/../Inputs/instrprof-debug-info-correlate-main.cpp %S/../Inputs/instrprof-debug-info-correlate-foo.cpp
+// RUN: env LLVM_PROFILE_FILE=%t.proflite %run %t
+// RUN: llvm-profdata merge -o %t.profdata --debug-info=%t %t.proflite --max-debug-info-correlation-warnings=2 2>&1 >/dev/null | FileCheck %s --check-prefixes=CHECK,LIMIT --implicit-check-not=warning
+// RUN: llvm-profdata merge -o %t.profdata --debug-info=%t %t.proflite --max-debug-info-correlation-warnings=0 2>&1 >/dev/null | FileCheck %s --check-prefixes=CHECK,NOLIMIT --implicit-check-not=warning
+
+// CHECK: warning: Could not find address of function
+// CHECK: warning: Could not find address of function
+// NOLIMIT: warning: Could not find address of function
+// NOLIMIT: warning: Could not find address of function
+// NOLIMIT: warning: Could not find address of function
+// LIMIT: warning: Suppressed 3 additional warnings

llvm/include/llvm/ProfileData/InstrProfCorrelator.h

@@ -36,10 +36,12 @@ class InstrProfCorrelator {
 
   /// Construct a ProfileData vector used to correlate raw instrumentation data
   /// to their functions.
-  virtual Error correlateProfileData() = 0;
+  /// \param MaxWarnings the maximum number of warnings to emit (0 = no limit)
+  virtual Error correlateProfileData(int MaxWarnings) = 0;
 
   /// Process debug info and dump the correlation data.
-  virtual Error dumpYaml(raw_ostream &OS) = 0;
+  /// \param MaxWarnings the maximum number of warnings to emit (0 = no limit)
+  virtual Error dumpYaml(int MaxWarnings, raw_ostream &OS) = 0;
 
   /// Return the number of ProfileData elements.
   std::optional<size_t> getDataSize() const;
@@ -131,11 +133,12 @@ class InstrProfCorrelatorImpl : public InstrProfCorrelator {
 protected:
   std::vector<RawInstrProf::ProfileData<IntPtrT>> Data;
 
-  Error correlateProfileData() override;
+  Error correlateProfileData(int MaxWarnings) override;
   virtual void correlateProfileDataImpl(
+      int MaxWarnings,
       InstrProfCorrelator::CorrelationData *Data = nullptr) = 0;
 
-  Error dumpYaml(raw_ostream &OS) override;
+  Error dumpYaml(int MaxWarnings, raw_ostream &OS) override;
 
   void addProbe(StringRef FunctionName, uint64_t CFGHash, IntPtrT CounterOffset,
                 IntPtrT FunctionPtr, uint32_t NumCounters);
@@ -197,7 +200,10 @@ class DwarfInstrProfCorrelator : public InstrProfCorrelatorImpl<IntPtrT> {
   ///       NULL
   ///     NULL
   /// \endcode
+  /// \param MaxWarnings the maximum number of warnings to emit (0 = no limit)
+  /// \param Data if provided, populate with the correlation data found
   void correlateProfileDataImpl(
+      int MaxWarnings,
       InstrProfCorrelator::CorrelationData *Data = nullptr) override;
 };
 

llvm/lib/ProfileData/InstrProfCorrelator.cpp

@@ -16,6 +16,8 @@
 #include "llvm/DebugInfo/DWARF/DWARFUnit.h"
 #include "llvm/Object/MachO.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/Format.h"
+#include "llvm/Support/WithColor.h"
 #include <optional>
 
 #define DEBUG_TYPE "correlator"
@@ -142,9 +144,9 @@ InstrProfCorrelatorImpl<IntPtrT>::get(
 }
 
 template <class IntPtrT>
-Error InstrProfCorrelatorImpl<IntPtrT>::correlateProfileData() {
+Error InstrProfCorrelatorImpl<IntPtrT>::correlateProfileData(int MaxWarnings) {
   assert(Data.empty() && Names.empty() && NamesVec.empty());
-  correlateProfileDataImpl();
+  correlateProfileDataImpl(MaxWarnings);
   if (Data.empty() || NamesVec.empty())
     return make_error<InstrProfError>(
         instrprof_error::unable_to_correlate_profile,
@@ -180,9 +182,10 @@ template <> struct yaml::SequenceElementTraits<InstrProfCorrelator::Probe> {
 };
 
 template <class IntPtrT>
-Error InstrProfCorrelatorImpl<IntPtrT>::dumpYaml(raw_ostream &OS) {
+Error InstrProfCorrelatorImpl<IntPtrT>::dumpYaml(int MaxWarnings,
+                                                 raw_ostream &OS) {
   InstrProfCorrelator::CorrelationData Data;
-  correlateProfileDataImpl(&Data);
+  correlateProfileDataImpl(MaxWarnings, &Data);
   if (Data.Probes.empty())
     return make_error<InstrProfError>(
         instrprof_error::unable_to_correlate_profile,
@@ -260,7 +263,10 @@ bool DwarfInstrProfCorrelator<IntPtrT>::isDIEOfProbe(const DWARFDie &Die) {
 
 template <class IntPtrT>
 void DwarfInstrProfCorrelator<IntPtrT>::correlateProfileDataImpl(
-    InstrProfCorrelator::CorrelationData *Data) {
+    int MaxWarnings, InstrProfCorrelator::CorrelationData *Data) {
+  bool UnlimitedWarnings = (MaxWarnings == 0);
+  // -N suppressed warnings means we can emit up to N (unsuppressed) warnings
+  int NumSuppressedWarnings = -MaxWarnings;
   auto maybeAddProbe = [&](DWARFDie Die) {
     if (!isDIEOfProbe(Die))
       return;
@@ -297,28 +303,30 @@ void DwarfInstrProfCorrelator<IntPtrT>::correlateProfileDataImpl(
       }
     }
     if (!FunctionName || !CFGHash || !CounterPtr || !NumCounters) {
-      LLVM_DEBUG(dbgs() << "Incomplete DIE for probe\n\tFunctionName: "
-                        << FunctionName << "\n\tCFGHash: " << CFGHash
-                        << "\n\tCounterPtr: " << CounterPtr
-                        << "\n\tNumCounters: " << NumCounters);
-      LLVM_DEBUG(Die.dump(dbgs()));
+      if (UnlimitedWarnings || ++NumSuppressedWarnings < 1) {
+        WithColor::warning()
+            << "Incomplete DIE for function " << FunctionName
+            << ": CFGHash=" << CFGHash << "  CounterPtr=" << CounterPtr
+            << "  NumCounters=" << NumCounters << "\n";
+        LLVM_DEBUG(Die.dump(dbgs()));
+      }
       return;
     }
     uint64_t CountersStart = this->Ctx->CountersSectionStart;
     uint64_t CountersEnd = this->Ctx->CountersSectionEnd;
     if (*CounterPtr < CountersStart || *CounterPtr >= CountersEnd) {
-      LLVM_DEBUG(
-          dbgs() << "CounterPtr out of range for probe\n\tFunction Name: "
-                 << FunctionName << "\n\tExpected: [0x"
-                 << Twine::utohexstr(CountersStart) << ", 0x"
-                 << Twine::utohexstr(CountersEnd) << ")\n\tActual: 0x"
-                 << Twine::utohexstr(*CounterPtr));
-      LLVM_DEBUG(Die.dump(dbgs()));
+      if (UnlimitedWarnings || ++NumSuppressedWarnings < 1) {
+        WithColor::warning()
+            << format("CounterPtr out of range for function %s: Actual=0x%x "
+                      "Expected=[0x%x, 0x%x)\n",
+                      *FunctionName, *CounterPtr, CountersStart, CountersEnd);
+        LLVM_DEBUG(Die.dump(dbgs()));
+      }
       return;
     }
-    if (!FunctionPtr) {
-      LLVM_DEBUG(dbgs() << "Could not find address of " << *FunctionName
-                        << "\n");
+    if (!FunctionPtr && (UnlimitedWarnings || ++NumSuppressedWarnings < 1)) {
+      WithColor::warning() << format("Could not find address of function %s\n",
+                                     *FunctionName);
       LLVM_DEBUG(Die.dump(dbgs()));
     }
     IntPtrT CounterOffset = *CounterPtr - CountersStart;
@@ -348,4 +356,8 @@ void DwarfInstrProfCorrelator<IntPtrT>::correlateProfileDataImpl(
   for (auto &CU : DICtx->dwo_units())
     for (const auto &Entry : CU->dies())
       maybeAddProbe(DWARFDie(CU.get(), &Entry));
+
+  if (!UnlimitedWarnings && NumSuppressedWarnings > 0)
+    WithColor::warning() << format("Suppressed %d additional warnings\n",
+                                   NumSuppressedWarnings);
 }

llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp

@@ -1056,12 +1056,6 @@ InstrProfiling::getOrCreateRegionCounters(InstrProfInstBase *Inc) {
           Annotations);
       CounterPtr->addDebugInfo(DICounter);
       DB.finalize();
-    } else {
-      std::string Msg = ("Missing debug info for function " + Fn->getName() +
-                         "; required for profile correlation.")
-                            .str();
-      Ctx.diagnose(
-          DiagnosticInfoPGOProfile(M->getName().data(), Msg, DS_Warning));
     }
   }
 

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

@@ -407,8 +407,8 @@ static void
 mergeInstrProfile(const WeightedFileVector &Inputs, StringRef DebugInfoFilename,
                   SymbolRemapper *Remapper, StringRef OutputFilename,
                   ProfileFormat OutputFormat, uint64_t TraceReservoirSize,
-                  uint64_t MaxTraceLength, bool OutputSparse,
-                  unsigned NumThreads, FailureMode FailMode,
+                  uint64_t MaxTraceLength, int MaxDbgCorrelationWarnings,
+                  bool OutputSparse, unsigned NumThreads, FailureMode FailMode,
                   const StringRef ProfiledBinary) {
   if (OutputFormat == PF_Compact_Binary)
     exitWithError("Compact Binary is deprecated");
@@ -421,7 +421,7 @@ mergeInstrProfile(const WeightedFileVector &Inputs, StringRef DebugInfoFilename,
     if (auto Err =
             InstrProfCorrelator::get(DebugInfoFilename).moveInto(Correlator))
       exitWithError(std::move(Err), DebugInfoFilename);
-    if (auto Err = Correlator->correlateProfileData())
+    if (auto Err = Correlator->correlateProfileData(MaxDbgCorrelationWarnings))
       exitWithError(std::move(Err), DebugInfoFilename);
   }
 
@@ -1270,6 +1270,11 @@ static int merge_main(int argc, const char *argv[]) {
   cl::opt<std::string> DebugInfoFilename(
       "debug-info", cl::init(""),
       cl::desc("Use the provided debug info to correlate the raw profile."));
+  cl::opt<unsigned> MaxDbgCorrelationWarnings(
+      "max-debug-info-correlation-warnings",
+      cl::desc("The maximum number of warnings to emit when correlating "
+               "profile from debug info (0 = no limit)"),
+      cl::init(5));
   cl::opt<std::string> ProfiledBinary(
       "profiled-binary", cl::init(""),
       cl::desc("Path to binary from which the profile was collected."));
@@ -1331,8 +1336,8 @@ static int merge_main(int argc, const char *argv[]) {
     mergeInstrProfile(WeightedInputs, DebugInfoFilename, Remapper.get(),
                       OutputFilename, OutputFormat,
                       TemporalProfTraceReservoirSize,
-                      TemporalProfMaxTraceLength, OutputSparse, NumThreads,
-                      FailureMode, ProfiledBinary);
+                      TemporalProfMaxTraceLength, MaxDbgCorrelationWarnings,
+                      OutputSparse, NumThreads, FailureMode, ProfiledBinary);
   else
     mergeSampleProfile(WeightedInputs, Remapper.get(), OutputFilename,
                        OutputFormat, ProfileSymbolListFile, CompressAllSections,
@@ -2877,19 +2882,20 @@ static int showMemProfProfile(const std::string &Filename,
 static int showDebugInfoCorrelation(const std::string &Filename,
                                     bool ShowDetailedSummary,
                                     bool ShowProfileSymbolList,
+                                    int MaxDbgCorrelationWarnings,
                                     ShowFormat SFormat, raw_fd_ostream &OS) {
   if (SFormat == ShowFormat::Json)
     exitWithError("JSON output is not supported for debug info correlation");
   std::unique_ptr<InstrProfCorrelator> Correlator;
   if (auto Err = InstrProfCorrelator::get(Filename).moveInto(Correlator))
     exitWithError(std::move(Err), Filename);
   if (SFormat == ShowFormat::Yaml) {
-    if (auto Err = Correlator->dumpYaml(OS))
+    if (auto Err = Correlator->dumpYaml(MaxDbgCorrelationWarnings, OS))
       exitWithError(std::move(Err), Filename);
     return 0;
   }
 
-  if (auto Err = Correlator->correlateProfileData())
+  if (auto Err = Correlator->correlateProfileData(MaxDbgCorrelationWarnings))
     exitWithError(std::move(Err), Filename);
 
   InstrProfSymtab Symtab;
@@ -2989,6 +2995,11 @@ static int show_main(int argc, const char *argv[]) {
       "debug-info", cl::init(""),
       cl::desc("Read and extract profile metadata from debug info and show "
                "the functions it found."));
+  cl::opt<unsigned> MaxDbgCorrelationWarnings(
+      "max-debug-info-correlation-warnings",
+      cl::desc("The maximum number of warnings to emit when correlating "
+               "profile from debug info (0 = no limit)"),
+      cl::init(5));
   cl::opt<bool> ShowCovered(
       "covered", cl::init(false),
       cl::desc("Show only the functions that have been executed."));
@@ -3022,7 +3033,8 @@ static int show_main(int argc, const char *argv[]) {
 
   if (!DebugInfoFilename.empty())
     return showDebugInfoCorrelation(DebugInfoFilename, ShowDetailedSummary,
-                                    ShowProfileSymbolList, SFormat, OS);
+                                    ShowProfileSymbolList,
+                                    MaxDbgCorrelationWarnings, SFormat, OS);
 
   if (ProfileKind == instr)
     return showInstrProfile(