[InstrProf][correlation] Read DWARFv5 `OP_addrx` location

[ellis]

Summary

Correctly read OP_addrx type encodings for DWARFv5 locations.

[ellis]

The original crash is here https://github.com/llvm/llvm-project/issues/53387

[dblaikie]

llvm/lib/ProfileData/InstrProfCorrelator.cpp

130–133

This should probably be committed separately & ideally with a test case.

178–184

Could you use DWARFUnit::getAddrOffsetSectionItem, perhaps?

(& I guess this would be committed along with an additional test case that covers DWARFv5 or swapping back the temporary change for the existing test case (probably should keep some v4 coverage too, for the DW_OP_addr case above))

[ellis]

Simplify code and add test

[ellis]

llvm/lib/ProfileData/InstrProfCorrelator.cpp

178–184

Ah thanks, that makes the code much simpler!

[dblaikie]

Looks good, thanks!

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

 // REQUIRES: zlib
 
 // Value profiling is currently not supported in lightweight mode.
-// RUN: %clang_pgogen -o %t -g -gdwarf-4 -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
-
 // RUN: %clang_pgogen -o %t.normal -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.profraw %run %t.normal
 // RUN: llvm-profdata merge -o %t.normal.profdata %t.profraw
 
+// RUN: %clang_pgogen -o %t.d4 -g -gdwarf-4 -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.d4.proflite %run %t.d4
+// RUN: llvm-profdata merge -o %t.d4.profdata --debug-info=%t.d4 %t.d4.proflite
+
+// RUN: diff %t.normal.profdata %t.d4.profdata
+
+// RUN: %clang_pgogen -o %t -g -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
+
 // RUN: diff %t.normal.profdata %t.profdata

llvm/lib/ProfileData/InstrProfCorrelator.cpp

InstrProfCorrelatorImpl<IntPtrT>::get(
   }
   return make_error<InstrProfError>(instrprof_error::unsupported_debug_format);
 }
 
 template <class IntPtrT>
 Error InstrProfCorrelatorImpl<IntPtrT>::correlateProfileData() {
   assert(Data.empty() && CompressedNames.empty() && Names.empty());
   correlateProfileDataImpl();
   auto Result =
       collectPGOFuncNameStrings(Names, /*doCompression=*/true, CompressedNames);
   CounterOffsets.clear();
   Names.clear();
   return Result;
 }
 
 template <class IntPtrT>
 void InstrProfCorrelatorImpl<IntPtrT>::addProbe(StringRef FunctionName,
                                                 uint64_t CFGHash,
                                                 IntPtrT CounterOffset,
                                                 IntPtrT FunctionPtr,

 llvm::Optional<uint64_t>
 DwarfInstrProfCorrelator<IntPtrT>::getLocation(const DWARFDie &Die) const {
   auto Locations = Die.getLocations(dwarf::DW_AT_location);
   if (!Locations) {
     consumeError(Locations.takeError());
     return {};
   }
   auto &DU = *Die.getDwarfUnit();
-  for (auto &Location : *Locations) {
-    auto AddressSize = DU.getAddressByteSize();
+  for (auto &Location : *Locations) {
     DataExtractor Data(Location.Expr, DICtx->isLittleEndian(), AddressSize);
     DWARFExpression Expr(Data, AddressSize);
-    for (auto &Op : Expr)
-      if (Op.getCode() == dwarf::DW_OP_addr)
+    for (auto &Op : Expr) {
+      if (Op.getCode() == dwarf::DW_OP_addr) {
         return Op.getRawOperand(0);
+      } else if (Op.getCode() == dwarf::DW_OP_addrx) {
+        uint64_t Index = Op.getRawOperand(0);
+        if (auto SA = DU.getAddrOffsetSectionItem(Index))
+          return SA->Address;
+      }
+    }
   }
   return {};
 }
 
 template <class IntPtrT>
 bool DwarfInstrProfCorrelator<IntPtrT>::isDIEOfProbe(const DWARFDie &Die) {
   const auto &ParentDie = Die.getParent();
   if (!Die.isValid() || !ParentDie.isValid() || Die.isNULL())
     return false;
   if (Die.getTag() != dwarf::DW_TAG_variable)