dwp check overflow

[zhuna8616]

This patch checks whether certain section overflows when generating a dwp file. If overflow occurs, llvm-dwp fails fast and dump info on the subject.

This is supposed to backport to branch release/11.x.

[ayermolo]

llvm/tools/llvm-dwp/llvm-dwp.cpp

63

Please make sure this doesn't break https://reviews.llvm.org/D137882
It relies on overflow behavior.

[zhuna8616]

llvm/tools/llvm-dwp/llvm-dwp.cpp

63

When nothing overflows, getLimitedValue simply returns the raw data of this APInt. Since there is an overflow check, this is synonyms to something like getValue.

[steven.zhang]

I didn't see any tests in the PR. Please add one.

llvm/tools/llvm-dwp/llvm-dwp.cpp

59–60

("Section size overflow in " + SectionPair->first()).str() ?

[steven.zhang]

llvm/tools/llvm-dwp/llvm-dwp.cpp

53–60

please don't hard code the 32 here. Maybe, you can use sizeof(ContributionOffsets[Index]) or other api that APInt have.

[zhuna8616]

llvm/tools/llvm-dwp/llvm-dwp.cpp

63

I tried it on your test case in https://reviews.llvm.org/D137882 and passed.

[ayermolo]

llvm/tools/llvm-dwp/llvm-dwp.cpp

63

Sorry wasn't clear. That test doesn't use llvm-dwp, I just pointed to the diff to point out that there is a code in llvm that relies on overflow behavior to reconstruct cu-index.
There is a downstream option for us that changes error for previous check into warning. Forgot I didn't upstream it.
https://github.com/llvm/llvm-project/blob/265ea1c7459da95b7a1d30718ac9f970a3ecc8d1/llvm/lib/DWP/DWP.cpp#L672
(which probably should be removed if check is added here).
Actually now that all the changes have landed in llvm and lldb, maybe there should be an option to turn it into an warning? At least for .debug_info part.

[zhuna8616]

llvm/tools/llvm-dwp/llvm-dwp.cpp

63

This patch is meant to backport llvm/11.x version, where no overflow check exists. The latest implementation checks overflow in debug_info section only. Am I supposed to turn the error introduced in this patch to a warning?

[ayermolo]

llvm/tools/llvm-dwp/llvm-dwp.cpp

63

No. I am proposing adding an option that when it's turned on this becomes a warning, and overflow behavior is preserved.
Also since this patch also checks .debug_info overflow, the other check can be removed.

[zhuna8616]

tests added

[zhuna8616]

no hard code 32

[zhuna8616]

commit squashed && test files added

[zhuna8616]

I added a test case for detecting overflow cases. I will look into the error to warning option presently.

The gist of the test is:

• create 2 simple C code files main.c, hello.c with skeleton functions, one calling the other
• compile them with split-dwarf option on to assembly code
• manually change the section attribute of hello.s .debug_info.dwo, and let the section have size close to 2^32-1
• compile & link the 2 .s files and llvm-dwp the linked result

The last step should produce an error prompt, indicating an overflow.

[zhuna8616]

overflow error to warning option

[ayermolo]

llvm/lib/MC/MCTargetOptionsCommandFlags.cpp

90 ↗

(On Diff #502986)

I don't see a reason why this should be MC layer option. Can you move it to llvm-dwp?

llvm/test/tools/llvm-dwp/X86/overflow-warning.test

4 ↗

(On Diff #502986)

Can you check that overflow behavior is preserved?

llvm/tools/llvm-dwp/llvm-dwp.cpp

53–60

I think this will break the overflow behavior that llvm patch I references relies on.

APInt APInt::uadd_sat(const APInt &RHS) const {
  bool Overflow;
  APInt Res = uadd_ov(RHS, Overflow);
  if (!Overflow)
    return Res;
 
  return APInt::getMaxValue(BitWidth);
}

[ayermolo]

llvm/tools/llvm-dwp/llvm-dwp.cpp

53–60

I think this will break the overflow behavior that llvm patch I references relies on.

APInt APInt::uadd_sat(const APInt &RHS) const {
  bool Overflow;
  APInt Res = uadd_ov(RHS, Overflow);
  if (!Overflow)
    return Res;
 
  return APInt::getMaxValue(BitWidth);
}

53–60

I think this will break the overflow behavior that llvm patch I references relies on.

APInt APInt::uadd_sat(const APInt &RHS) const {
  bool Overflow;
  APInt Res = uadd_ov(RHS, Overflow);
  if (!Overflow)
    return Res;
 
  return APInt::getMaxValue(BitWidth);
}

errr, messeed up APIs. never mind.

[ayermolo]

llvm/lib/MC/MCTargetOptionsCommandFlags.cpp

91 ↗

(On Diff #502986)

For name maybe:

static cl::opt<bool> ContinueOnCuIndexOverflow(

"continue-on-cu-index-overflow",
cl::desc("This turns an error when offset for .debug sections "
         "overfolws into a warning."),

?

[zhuna8616]

llvm/test/tools/llvm-dwp/X86/overflow-warning.test

4 ↗

(On Diff #502986)

Do I check it as in https://reviews.llvm.org/D137882 ? I may have to copy much of the code if I am to check overflow behavior as in this post.

I found a invalid_cu_index.test that goes like:

RUN: not llvm-dwp %p/../Inputs/invalid_cu_index/x.dwp -o %t 2>&1 | FileCheck %s
CHECK: error: failed to parse cu_index

Looks like it's parsing cu index with llvm-dwp directly. I added a similar check and it passed.

RUN: llvm-dwp overflow.dwp -o overflow-warned.dwp

Is this line of code sufficient for verifying overflow behavior? Or should I follow this post https://reviews.llvm.org/D137882 instead?

[zhuna8616]

move warning option to dwp dayer && add check for invalid sequence

[ayermolo]

You might want to rebase this on trunk LLVM. Seems like you are pushing changes from an old version.

llvm/test/tools/llvm-dwp/X86/overflow-warning.test

4 ↗

(On Diff #502986)

Sorry should have been more clear. With option that turns it in to a warning can you check that for sections that overflow have correct reconstructed offset:

# RUN: llvm-dwarfdump --manaully-generate-unit-index --debug-cu-index %t.dwp | FileCheck %s

The test in that diff uses zero
At least locally. The test in comments uses: .zero 0xfffffff0 - 0x2b # 0xfffffff0 is mimimum reserved length
Which actually creates a 4GB file on disk. Don't think we want that in build bots.

[zhuna8616]

We intend this for llvm release/11.x version. Perhaps this can go as a backport?

[ayermolo]

In D144565#4183779, @zhuna8616 wrote:

We intend this for llvm release/11.x version. Perhaps this can go as a backport?

ah my apologies. I thought you were going to push it to trunk, and then backport internally to 11.x. Wrong mental model. :)
TBH I am not sure what the procedure is for pushing just to release branch. Maybe Tom Stellard will know.

[steven.zhang]

In D144565#4183779, @zhuna8616 wrote:

We intend this for llvm release/11.x version. Perhaps this can go as a backport?

Maybe, go into the master first, and then, considering the service line (Patches won't go into those lines except that they are critical bug fixes, as I know)

[zhuna8616]

I made another patch https://reviews.llvm.org/D146289

[zhuna8616]

This comment was removed by zhuna8616.

[zhuna8616]

Also updated here after rebase.

[steven.zhang]

Some minor comments.

llvm/lib/DWP/DWP.cpp

185

Do you format the changes ?

186

I would prefer to use the StringRef to concat them, and then, convert base to std::string.

236

Please remove the {} if there is only one statement in the if clause. The same rule applies in other changes.

727–728

Remove this comments.

llvm/test/tools/llvm-dwp/Inputs/overflow/debug_info.s

79 ↗

(On Diff #506527)

remove such kind of information

llvm/test/tools/llvm-dwp/X86/overflow_debug_info.test

2 ↗

(On Diff #506527)

How about the dwarf 4 ?

[dblaikie]

llvm/lib/DWP/DWP.cpp

236

We'd also usually roll in the initialization to the if condition, and prefer = init over () init (avoids explicit conversions - so it's easier to read without worrying about any more "interesting" conversions happening):

if (Error Err = sectionOverflowErrorOrWarning(...))
  return Err;

[ayermolo]

To clarify https://reviews.llvm.org/D146289 will be going into the trunk right?

[ayermolo]

Don't really have a strong opinion, but maybe other reviewers do. Right now we have two types of checks;
pre condition check:
std::numeric_limits<uint32_t>::max() - InfoSectionOffset <

C.getLength32()

and
post condition check:
OldOffset > TypesOffset

Should this be standardized to one or the other type of check?

llvm/lib/DWP/DWP.cpp

231

Maybe a static_assert that sizeof(OldOffset) == sizeof(TypeOffset)?

686

OldOffset > ContributionOffsets[Index]
Just to keep it consistent with other checks.

llvm/test/tools/llvm-dwp/X86/overflow_debug_info.test

2 ↗

(On Diff #506527)

Actually looking at assembly those are DWARF4 tests.
example:

.short	4                               # DWARF version number

.byte 4 # DW_AT_GNU_dwo_name
.quad -346972125991005518 # DW_AT_GNU_dwo_id

[zhuna8616]

fix comments & added dwarf v4 and v5 checks & removed sensitive info

[zhuna8616]

I removed the debug_str section checks because it seemed redundant.

Also made separate tests for dwarf v4 v5.

llvm/lib/DWP/DWP.cpp

185

done

186

done

231

done

236

done

686

done

727–728

done

llvm/test/tools/llvm-dwp/Inputs/overflow/debug_info.s

79 ↗

(On Diff #506527)

done

[zhuna8616]

removed even more sensitive info

[zhuna8616]

In D144565#4225265, @ayermolo wrote:

To clarify https://reviews.llvm.org/D146289 will be going into the trunk right?

This post is rebased to main so D146289 is obsolete. This one can goto trunk.

[zhuna8616]

diff again master

[ayermolo]

For. your assembly tests. Can you add comment(s) for parts that you have modified to make the overflow happen.
Also maybe add what c/c++ was used to generate it.
For. your tests please add description of what they are doing.

llvm/lib/DWP/DWP.cpp

232

I don't think this is the same as sizeof(OldOffset) == sizeof(TypesOffset)

861

Is this because of tabs?

[zhuna8616]

llvm/lib/DWP/DWP.cpp

232

Err... typos... My bad

861

Is this a format issue? Should I make it like this:

if (Error Err = addAllTypesFromDWP(Out, TypeIndexEntries, TUIndex, OutSection,
                                   TypeInputSection, CurEntry,
                                   ContributionOffsets[TypesContributionIndex],
                                   TypesContributionIndex))

Or should I add a tab to the left of addAllTypesFromDWP?

[ayermolo]

llvm/lib/DWP/DWP.cpp

861

Just wondering if you have tab enabled in your IDE. From what I remember at least on windows VS it's the default, and you need to change it to 4 spaces.

[ayermolo]

llvm/lib/DWP/DWP.cpp

232

To be clear I think it's still a good idea to have the static_assert since you are relying on both being same type in your check.
static_assert(sizeof(OldOffset) == sizeof(TypesOffset)));

[zhuna8616]

• fix tabs & static_assert & added comments to tests

[steven.zhang]

LGTM now with one minor comment. But please hold on to see if ayermolo has other comments.

llvm/test/tools/llvm-dwp/Inputs/overflow/main_v4.s

6

-c here is not needed.

[zhuna8616]

format & remove minor changes

• remove -c
• format

[zhuna8616]

gentle ping

[zhuna8616]

gentle ping @ayermolo

[ayermolo]

My apologies, it's been a busy last couple of weeks.
Looks fine to me.
I would add static_assert(sizeof(OldOffset) == sizeof(TypesOffset)); checks for other places where you do similar > comparisons.
@dblaikie do you have any comments? :)

[ayermolo]

Also looks like one of your pre-merge checks has failed with build error:

ld.lld: error: undefined symbol: DwpCategory

referenced by CommandLine.h:473 (/var/lib/buildkite-agent/builds/llvm-project/llvm/include/llvm/Support/CommandLine.h:473)

DWP.cpp.o:(_GLOBAL__sub_I_DWP.cpp) in archive lib/libLLVMDWP.a

[dblaikie]

Could this have a more verbose/explicit description? I thought there was already some overflow checking in llvm-dwp - so it'd be good to describe in more detail which cases this is intended to add.

[zhuna8616]

This patch is intended to add overflow checks to all dwo sections. Previous versions check whether debug_info section overflows, ignoring other sections.

This patch also adds tests for overflow cases, verifying that new code does report overflow when it happens.

[zhuna8616]

• format
• move ContinueOnCuIndexOverflow option decl

[dblaikie]

llvm/test/tools/llvm-dwp/Inputs/overflow/debug_info_v5.s

4–5

This is going to create rather large files on test machines, which is a bit concerning...

Is there precedent for this/maybe it needs some broader discussion? (or maybe we leave these tests around but with manual repro steps/some way to opt-in to them with an env variable or lit flag or something)

[zhuna8616]

Perhaps @ayermolo can shed some light on a precedent case.

[ayermolo]

Well when I added a check I had a local test and posted it as part of a review, but not committed. I think there was the same concern about the size. Although I did it with explict .zero op.

[dblaikie]

Yeah, I wouldn't mind the tests being included somewhere off by default in some way. I don't think it's feasible to have single tests create 4GB+ of temp/output files.

[zhuna8616]

We have to make huge files, or overflow won't happen. Perhaps we can disable the related test by default in lit, making it run on demand?

[steven.zhang]

I think, this warning is quite important. Without it, we will silently generate a bad dwp, And it will crash the gdb or report something like: invalid dwarf version, which is really confusion and hard to address the root cause. Maybe, we can remove such tests if the size of the test output is the concern. What do you think ? @ayermolo @dblaikie

[dblaikie]

Yeah. Please submit this without any tests that produce 4GB/large amount sof data on test machines.Either include those tests with some sort of "manual" marking (eg: with "manual" as a suffix so they don't get picked up by the usual lit test globs) or perhaps omitting them entirely (they'll still be here in the code review history). Awkward either way.

If you happen to be up for looking around to see if there's any precedent/other manual tests in LLVM - maybe this patch can be consistent with however those are annotated

[lizhengxian.123]

• rename overflow tests with manual suffix

[zhuna8616]

• rename overflow tests with manual suffix

[zhuna8616]

Sorry about the name hazard... @lizhengxian.123 this guy's git config somehow overwrote everyone's.

[zhuna8616]

I do not have commit access. Perhaps someone else should commit this.

[zhuna8616]

This comment was removed by zhuna8616.

[ayermolo]

Looks like pre-merge check clang-format is failing.

[zhuna8616]

This is weird. I am unable to reproduce clang-format error locally.

These are the steps to reproduce according to https://buildkite.com/llvm-project/premerge-checks/builds/154962#01885cac-1fac-4352-af57-3fc9634f6010.

rm -rf build
mkdir build
cd build
export CC="clang"
export CXX="clang++"
export LD="LLD"
cmake ../llvm -D LLVM_ENABLE_PROJECTS="libc;flang;polly;lld;llvm;clang;bolt;mlir;compiler-rt;clang-tools-extra" -G Ninja -D CMAKE_BUILD_TYPE=Release -D LLVM_ENABLE_ASSERTIONS=ON -D LLVM_BUILD_EXAMPLES=ON -D COMPILER_RT_BUILD_LIBFUZZER=OFF -D LLVM_LIT_ARGS="-v --xunit-xml-output test-results.xml" -D LLVM_ENABLE_LLD=ON -D CMAKE_CXX_FLAGS=-gmlt -DBOLT_CLANG_EXE=/usr/bin/clang
# ^note that compiler cache arguments are omitted
ln -s $PWD/compile_commands.json ../compile_commands.json
ninja check-all check-clang-tools check-polly check-clang check-llvm check-flang check-mlir check-lld check-libc check-bolt
cd ..
git-clang-format HEAD~1

I executed them and got.

no modified files to format

Is there anything more to it before executing git-clang-format?

[ayermolo]

In D144565#4377842, @zhuna8616 wrote:

This is weird. I am unable to reproduce clang-format error locally.

These are the steps to reproduce according to https://buildkite.com/llvm-project/premerge-checks/builds/154962#01885cac-1fac-4352-af57-3fc9634f6010.

rm -rf build
mkdir build
cd build
export CC="clang"
export CXX="clang++"
export LD="LLD"
cmake ../llvm -D LLVM_ENABLE_PROJECTS="libc;flang;polly;lld;llvm;clang;bolt;mlir;compiler-rt;clang-tools-extra" -G Ninja -D CMAKE_BUILD_TYPE=Release -D LLVM_ENABLE_ASSERTIONS=ON -D LLVM_BUILD_EXAMPLES=ON -D COMPILER_RT_BUILD_LIBFUZZER=OFF -D LLVM_LIT_ARGS="-v --xunit-xml-output test-results.xml" -D LLVM_ENABLE_LLD=ON -D CMAKE_CXX_FLAGS=-gmlt -DBOLT_CLANG_EXE=/usr/bin/clang
# ^note that compiler cache arguments are omitted
ln -s $PWD/compile_commands.json ../compile_commands.json
ninja check-all check-clang-tools check-polly check-clang check-llvm check-flang check-mlir check-lld check-libc check-bolt
cd ..
git-clang-format HEAD~1

I executed them and got.

no modified files to format

Is there anything more to it before executing git-clang-format?

try git-clang-format --commit HEAD~

[zhuna8616]

• format

[zhuna8616]

• format squashed

[zhuna8616]

Now that there is no problem. Perhaps we can finally commit?

[steven.zhang]

I will commit it for you.

llvm/include/llvm/DWP/DWP.h

 };
 
 struct CompileUnitIdentifiers {
   uint64_t Signature = 0;
   const char *Name = "";
   const char *DWOName = "";
 };
 
-Error write(MCStreamer &Out, ArrayRef<std::string> Inputs);
+Error write(MCStreamer &Out, ArrayRef<std::string> Inputs,
+            bool ContinueOnCuIndexOverflow);
 
 unsigned getContributionIndex(DWARFSectionKind Kind, uint32_t IndexVersion);
 
 Error handleSection(
     const StringMap<std::pair<MCSection *, DWARFSectionKind>> &KnownSections,
     const MCSection *StrSection, const MCSection *StrOffsetSection,
     const MCSection *TypesSection, const MCSection *CUIndexSection,
     const MCSection *TUIndexSection, const MCSection *InfoSection,

llvm/lib/DWP/DWP.cpp

 //===-- llvm-dwp.cpp - Split DWARF merging tool for llvm ------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
 // A utility for merging DWARF 5 Split DWARF .dwo files into .dwp (DWARF
 // package files).
 //
 //===----------------------------------------------------------------------===//
 #include "llvm/DWP/DWP.h"
+#include "llvm/ADT/Twine.h"
 #include "llvm/DWP/DWPError.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCObjectFileInfo.h"
 #include "llvm/MC/MCTargetOptionsCommandFlags.h"
 #include "llvm/Object/Decompressor.h"
 #include "llvm/Object/ELFObjectFile.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include <limits>
 
 using namespace llvm;
 using namespace llvm::object;
 
 static mc::RegisterMCTargetOptionsFlags MCTargetOptionsFlags;
 
static StringRef getSubsection(StringRef Section,
                                const DWARFUnitIndex::Entry &Entry,
                                DWARFSectionKind Kind) {
   const auto *Off = Entry.getContribution(Kind);
   if (!Off)
     return StringRef();
   return Section.substr(Off->getOffset(), Off->getLength());
 }
 
-static void
-addAllTypesFromDWP(MCStreamer &Out,
-                   MapVector<uint64_t, UnitIndexEntry> &TypeIndexEntries,
-                   const DWARFUnitIndex &TUIndex, MCSection *OutputTypes,
-                   StringRef Types, const UnitIndexEntry &TUEntry,
-                   uint32_t &TypesOffset, unsigned TypesContributionIndex) {
+static Error sectionOverflowErrorOrWarning(uint32_t PrevOffset,
+                                           uint32_t OverflowedOffset,
+                                           StringRef SectionName,
+                                           bool ContinueOnCuIndexOverflow) {
+  std::string Msg =
+      (SectionName +
+       Twine(" Section Contribution Offset overflow 4G. Previous Offset ") +
+       Twine(PrevOffset) + Twine(", After overflow offset ") +
+       Twine(OverflowedOffset) + Twine("."))
+          .str();
+  if (ContinueOnCuIndexOverflow) {
+    WithColor::defaultWarningHandler(make_error<DWPError>(Msg));
+    return Error::success();
+  }
+  return make_error<DWPError>(Msg);
+}
+
+static Error addAllTypesFromDWP(
+    MCStreamer &Out, MapVector<uint64_t, UnitIndexEntry> &TypeIndexEntries,
+    const DWARFUnitIndex &TUIndex, MCSection *OutputTypes, StringRef Types,
+    const UnitIndexEntry &TUEntry, uint32_t &TypesOffset,
+    unsigned TypesContributionIndex, bool ContinueOnCuIndexOverflow) {
   Out.switchSection(OutputTypes);
   for (const DWARFUnitIndex::Entry &E : TUIndex.getRows()) {
     auto *I = E.getContributions();
     if (!I)
       continue;
     auto P = TypeIndexEntries.insert(std::make_pair(E.getSignature(), TUEntry));
     if (!P.second)
       continue;
for (auto Kind : TUIndex.getColumnKinds()) {
       ++I;
     }
     auto &C = Entry.Contributions[TypesContributionIndex];
     Out.emitBytes(Types.substr(
         C.getOffset() -
             TUEntry.Contributions[TypesContributionIndex].getOffset(),
         C.getLength()));
     C.setOffset(TypesOffset);
+    uint32_t OldOffset = TypesOffset;
+    static_assert(sizeof(OldOffset) == sizeof(TypesOffset));
     TypesOffset += C.getLength();
+    if (OldOffset > TypesOffset) {
+      if (Error Err = sectionOverflowErrorOrWarning(
+              OldOffset, TypesOffset, "Types", ContinueOnCuIndexOverflow))
+        return Err;
+    }
   }
+  return Error::success();
 }
 
-static void addAllTypesFromTypesSection(
+static Error addAllTypesFromTypesSection(
     MCStreamer &Out, MapVector<uint64_t, UnitIndexEntry> &TypeIndexEntries,
     MCSection *OutputTypes, const std::vector<StringRef> &TypesSections,
-    const UnitIndexEntry &CUEntry, uint32_t &TypesOffset) {
+    const UnitIndexEntry &CUEntry, uint32_t &TypesOffset,
+    bool ContinueOnCuIndexOverflow) {
   for (StringRef Types : TypesSections) {
     Out.switchSection(OutputTypes);
     uint64_t Offset = 0;
     DataExtractor Data(Types, true, 0);
     while (Data.isValidOffset(Offset)) {
       UnitIndexEntry Entry = CUEntry;
       // Zero out the debug_info contribution
       Entry.Contributions[0] = {};
while (Data.isValidOffset(Offset)) {
       auto Signature = Data.getU64(&Offset);
       Offset = PrevOffset + C.getLength32();
 
       auto P = TypeIndexEntries.insert(std::make_pair(Signature, Entry));
       if (!P.second)
         continue;
 
       Out.emitBytes(Types.substr(PrevOffset, C.getLength32()));
+      uint32_t OldOffset = TypesOffset;
       TypesOffset += C.getLength32();
+      if (OldOffset > TypesOffset) {
+        if (Error Err = sectionOverflowErrorOrWarning(
+                OldOffset, TypesOffset, "types", ContinueOnCuIndexOverflow))
+          return Err;
       }
     }
   }
+  return Error::success();
+}
 
 static std::string buildDWODescription(StringRef Name, StringRef DWPName,
                                        StringRef DWOName) {
   std::string Text = "\'";
   Text += Name;
   Text += '\'';
   bool HasDWO = !DWOName.empty();
   bool HasDWP = !DWPName.empty();
else if (OutSection == InfoSection)
     CurInfoSection.push_back(Contents);
   else {
     Out.switchSection(OutSection);
     Out.emitBytes(Contents);
   }
   return Error::success();
 }
 
-Error write(MCStreamer &Out, ArrayRef<std::string> Inputs) {
+Error write(MCStreamer &Out, ArrayRef<std::string> Inputs,
+            bool ContinueOnCuIndexOverflow) {
   const auto &MCOFI = *Out.getContext().getObjectFileInfo();
   MCSection *const StrSection = MCOFI.getDwarfStrDWOSection();
   MCSection *const StrOffsetSection = MCOFI.getDwarfStrOffDWOSection();
   MCSection *const TypesSection = MCOFI.getDwarfTypesDWOSection();
   MCSection *const CUIndexSection = MCOFI.getDwarfCUIndexSection();
   MCSection *const TUIndexSection = MCOFI.getDwarfTUIndexSection();
   MCSection *const InfoSection = MCOFI.getDwarfInfoDWOSection();
   const StringMap<std::pair<MCSection *, DWARFSectionKind>> KnownSections = {
for (const auto &Input : Inputs) {
 
     writeStringsAndOffsets(Out, Strings, StrOffsetSection, CurStrSection,
                            CurStrOffsetSection, Header.Version);
 
     for (auto Pair : SectionLength) {
       auto Index = getContributionIndex(Pair.first, IndexVersion);
       CurEntry.Contributions[Index].setOffset(ContributionOffsets[Index]);
       CurEntry.Contributions[Index].setLength(Pair.second);
+      uint32_t OldOffset = ContributionOffsets[Index];
       ContributionOffsets[Index] += CurEntry.Contributions[Index].getLength32();
+      if (OldOffset > ContributionOffsets[Index]) {
+        uint32_t SectionIndex = 0;
+        for (auto &Section : Obj.sections()) {
+          if (SectionIndex == Index) {
+            return sectionOverflowErrorOrWarning(
+                OldOffset, ContributionOffsets[Index], *Section.getName(),
+                ContinueOnCuIndexOverflow);
+          }
+          ++SectionIndex;
+        }
+      }
     }
 
     uint32_t &InfoSectionOffset =
         ContributionOffsets[getContributionIndex(DW_SECT_INFO, IndexVersion)];
     if (CurCUIndexSection.empty()) {
       bool FoundCUUnit = false;
       Out.switchSection(InfoSection);
       for (StringRef Info : CurInfoSection) {
         uint64_t UnitOffset = 0;
         while (Info.size() > UnitOffset) {
           Expected<InfoSectionUnitHeader> HeaderOrError =
               parseInfoSectionUnitHeader(Info.substr(UnitOffset, Info.size()));
           if (!HeaderOrError)
             return HeaderOrError.takeError();
           InfoSectionUnitHeader &Header = *HeaderOrError;
 
           UnitIndexEntry Entry = CurEntry;
           auto &C = Entry.Contributions[getContributionIndex(DW_SECT_INFO,
                                                              IndexVersion)];
           C.setOffset(InfoSectionOffset);
           C.setLength(Header.Length + 4);
 
           if (std::numeric_limits<uint32_t>::max() - InfoSectionOffset <
-              C.getLength32())
-            return make_error<DWPError>(
-                "debug information section offset is greater than 4GB");
+              C.getLength32()) {
+            if (Error Err = sectionOverflowErrorOrWarning(
+                    InfoSectionOffset, InfoSectionOffset + C.getLength32(),
+                    "debug_info", ContinueOnCuIndexOverflow))
+              return Err;
+          }
 
           UnitOffset += C.getLength32();
           if (Header.Version < 5 ||
               Header.UnitType == dwarf::DW_UT_split_compile) {
             Expected<CompileUnitIdentifiers> EID = getCUIdentifiers(
                 Header, AbbrevSection,
                 Info.substr(UnitOffset - C.getLength32(), C.getLength32()),
                 CurStrOffsetSection, CurStrSection);
 
             if (!EID)
               return createFileError(Input, EID.takeError());
if (CurCUIndexSection.empty()) {
         }
       }
 
       if (!FoundCUUnit)
         return make_error<DWPError>("no compile unit found in file: " + Input);
 
       if (IndexVersion == 2) {
         // Add types from the .debug_types section from DWARF < 5.
-        addAllTypesFromTypesSection(
+        if (Error Err = addAllTypesFromTypesSection(
                 Out, TypeIndexEntries, TypesSection, CurTypesSection, CurEntry,
-            ContributionOffsets[getContributionIndex(DW_SECT_EXT_TYPES, 2)]);
+                ContributionOffsets[getContributionIndex(DW_SECT_EXT_TYPES, 2)],
+                ContinueOnCuIndexOverflow))
+          return Err;
       }
       continue;
     }
 
     if (CurInfoSection.size() != 1)
       return make_error<DWPError>("expected exactly one occurrence of a debug "
                                   "info section in a .dwp file");
     StringRef DwpSingleInfoSection = CurInfoSection.front();
if (!CurTUIndexSection.empty()) {
         return make_error<DWPError>("failed to parse tu_index");
       if (TUIndex.getVersion() != IndexVersion)
         return make_error<DWPError>("incompatible tu_index versions, found " +
                                     utostr(TUIndex.getVersion()) +
                                     " and expecting " + utostr(IndexVersion));
 
       unsigned TypesContributionIndex =
           getContributionIndex(TUSectionKind, IndexVersion);
-      addAllTypesFromDWP(Out, TypeIndexEntries, TUIndex, OutSection,
-                         TypeInputSection, CurEntry,
-                         ContributionOffsets[TypesContributionIndex],
-                         TypesContributionIndex);
+      if (Error Err = addAllTypesFromDWP(
+              Out, TypeIndexEntries, TUIndex, OutSection, TypeInputSection,
+              CurEntry, ContributionOffsets[TypesContributionIndex],
+              TypesContributionIndex, ContinueOnCuIndexOverflow))
+        return Err;
     }
   }
 
   if (Version < 5) {
     // Lie about there being no info contributions so the TU index only includes
     // the type unit contribution for DWARF < 5. In DWARFv5 the TU index has a
     // contribution to the info section, so we do not want to lie about it.
     ContributionOffsets[0] = 0;

llvm/test/tools/llvm-dwp/Inputs/overflow/debug_info_v4.s

+# Note: This file is compiled from the following code, for 
+#     the purpose of creating an overflowed dwo section.
+#       After being compiled from source, section `.debug_info.dwo`
+#       is changed to have length (2^32 - 30) Bytes, and added 
+#       padding with `.fill` directive, so it is likely to 
+#       overflow when packed with other files.
+# 
+# clang -g -S -gsplit-dwarf -gdwarf-4 hello.c
+#
+# #include <stdio.h>
+# void hello() {
+#     printf("hello\n");
+# }
+
+  .text
+  .file "hello.c"
+  .globl  hello                           # -- Begin function hello
+  .p2align  4, 0x90
+  .type hello,@function
+hello:                                  # @hello
+.Lfunc_begin0:
+  .file 1 "/xxxxxx/xxxx/xxxxxxxxxx/xxxxxxxx/hello" "hello.c"
+  .loc  1 3 0                           # hello.c:3:0
+  .cfi_startproc
+# %bb.0:
+  pushq %rbp
+  .cfi_def_cfa_offset 16
+  .cfi_offset %rbp, -16
+  movq  %rsp, %rbp
+  .cfi_def_cfa_register %rbp
+.Ltmp0:
+  .loc  1 4 5 prologue_end              # hello.c:4:5
+  movabsq $.L.str, %rdi
+  movb  $0, %al
+  callq printf
+  .loc  1 5 1                           # hello.c:5:1
+  popq  %rbp
+  .cfi_def_cfa %rsp, 8
+  retq
+.Ltmp1:
+.Lfunc_end0:
+  .size hello, .Lfunc_end0-hello
+  .cfi_endproc
+                                        # -- End function
+  .type .L.str,@object                  # @.str
+  .section  .rodata.str1.1,"aMS",@progbits,1
+.L.str:
+  .asciz  "hello\n"
+  .size .L.str, 7
+
+  .section  .debug_abbrev,"",@progbits
+  .byte 1                               # Abbreviation Code
+  .byte 17                              # DW_TAG_compile_unit
+  .byte 0                               # DW_CHILDREN_no
+  .byte 16                              # DW_AT_stmt_list
+  .byte 23                              # DW_FORM_sec_offset
+  .byte 27                              # DW_AT_comp_dir
+  .byte 14                              # DW_FORM_strp
+  .ascii  "\264B"                         # DW_AT_GNU_pubnames
+  .byte 25                              # DW_FORM_flag_present
+  .ascii  "\260B"                         # DW_AT_GNU_dwo_name
+  .byte 14                              # DW_FORM_strp
+  .ascii  "\261B"                         # DW_AT_GNU_dwo_id
+  .byte 7                               # DW_FORM_data8
+  .byte 17                              # DW_AT_low_pc
+  .byte 1                               # DW_FORM_addr
+  .byte 18                              # DW_AT_high_pc
+  .byte 6                               # DW_FORM_data4
+  .ascii  "\263B"                         # DW_AT_GNU_addr_base
+  .byte 23                              # DW_FORM_sec_offset
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 0                               # EOM(3)
+  .section  .debug_info,"",@progbits
+.Lcu_begin0:
+  # .long 4294967295   # 2^32 - 1    #44                              # Length of Unit
+  .long 44                              # Length of Unit
+  .short  4                               # DWARF version number
+  .long .debug_abbrev                   # Offset Into Abbrev. Section
+  .byte 8                               # Address Size (in bytes)
+  .byte 1                               # Abbrev [1] 0xb:0x25 DW_TAG_compile_unit
+  .long .Lline_table_start0             # DW_AT_stmt_list
+  .long .Lskel_string0                  # DW_AT_comp_dir
+                                        # DW_AT_GNU_pubnames
+  .long .Lskel_string1                  # DW_AT_GNU_dwo_name
+  .quad -94954012350180462              # DW_AT_GNU_dwo_id
+  .quad .Lfunc_begin0                   # DW_AT_low_pc
+  .long .Lfunc_end0-.Lfunc_begin0       # DW_AT_high_pc
+  .long .Laddr_table_base0              # DW_AT_GNU_addr_base
+  # .fill   4294967251   # = 2^32 - 1 - 44
+  .section  .debug_str,"MS",@progbits,1
+.Lskel_string0:
+  .asciz  "/xxxxxx/xxxx/xxxxxxxxxx/xxxxxxxx/hello" # string offset=0
+.Lskel_string1:
+  .asciz  "hello.dwo"                     # string offset=39
+  .section  .debug_str.dwo,"eMS",@progbits,1
+.Linfo_string0:
+  .asciz  "hello"                         # string offset=0
+.Linfo_string1:
+  .asciz  "clang version 11.1.0 (https://github.com/llvm/llvm-project.git 173544ee3d09cdce8665f2097f677c31e1f1a9a1)" # string offset=6
+.Linfo_string2:
+  .asciz  "hello.c"                       # string offset=111
+.Linfo_string3:
+  .asciz  "hello.dwo"                     # string offset=119
+  .section  .debug_str_offsets.dwo,"e",@progbits
+  .long 0
+  .long 6
+  .long 111
+  .long 119
+  .section  .debug_info.dwo,"e",@progbits
+  .long 4294967266   # 2^32 - 30        #33                              # Length of Unit
+  .short  4                               # DWARF version number
+  .long 0                               # Offset Into Abbrev. Section
+  .byte 8                               # Address Size (in bytes)
+  .byte 1                               # Abbrev [1] 0xb:0x1a DW_TAG_compile_unit
+  .byte 1                               # DW_AT_producer
+  .short  12                              # DW_AT_language
+  .byte 2                               # DW_AT_name
+  .byte 3                               # DW_AT_GNU_dwo_name
+  .quad -94954012350180462              # DW_AT_GNU_dwo_id
+  .byte 2                               # Abbrev [2] 0x19:0xb DW_TAG_subprogram
+  .byte 0                               # DW_AT_low_pc
+  .long .Lfunc_end0-.Lfunc_begin0       # DW_AT_high_pc
+  .byte 1                               # DW_AT_frame_base
+  .byte 86
+  .byte 0                               # DW_AT_name
+  .byte 1                               # DW_AT_decl_file
+  .byte 3                               # DW_AT_decl_line
+                                        # DW_AT_external
+  .byte 0                               # End Of Children Mark
+  .fill   4294967233  # 2^32 - 30 - 33
+  .section  .debug_abbrev.dwo,"e",@progbits
+  .byte 1                               # Abbreviation Code
+  .byte 17                              # DW_TAG_compile_unit
+  .byte 1                               # DW_CHILDREN_yes
+  .byte 37                              # DW_AT_producer
+  .ascii  "\202>"                         # DW_FORM_GNU_str_index
+  .byte 19                              # DW_AT_language
+  .byte 5                               # DW_FORM_data2
+  .byte 3                               # DW_AT_name
+  .ascii  "\202>"                         # DW_FORM_GNU_str_index
+  .ascii  "\260B"                         # DW_AT_GNU_dwo_name
+  .ascii  "\202>"                         # DW_FORM_GNU_str_index
+  .ascii  "\261B"                         # DW_AT_GNU_dwo_id
+  .byte 7                               # DW_FORM_data8
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 2                               # Abbreviation Code
+  .byte 46                              # DW_TAG_subprogram
+  .byte 0                               # DW_CHILDREN_no
+  .byte 17                              # DW_AT_low_pc
+  .ascii  "\201>"                         # DW_FORM_GNU_addr_index
+  .byte 18                              # DW_AT_high_pc
+  .byte 6                               # DW_FORM_data4
+  .byte 64                              # DW_AT_frame_base
+  .byte 24                              # DW_FORM_exprloc
+  .byte 3                               # DW_AT_name
+  .ascii  "\202>"                         # DW_FORM_GNU_str_index
+  .byte 58                              # DW_AT_decl_file
+  .byte 11                              # DW_FORM_data1
+  .byte 59                              # DW_AT_decl_line
+  .byte 11                              # DW_FORM_data1
+  .byte 63                              # DW_AT_external
+  .byte 25                              # DW_FORM_flag_present
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 0                               # EOM(3)
+  .section  .debug_addr,"",@progbits
+.Laddr_table_base0:
+  .quad .Lfunc_begin0
+  .section  .debug_gnu_pubnames,"",@progbits
+  .long .LpubNames_end0-.LpubNames_begin0 # Length of Public Names Info
+.LpubNames_begin0:
+  .short  2                               # DWARF Version
+  .long .Lcu_begin0                     # Offset of Compilation Unit Info
+  .long 48                              # Compilation Unit Length
+  .long 25                              # DIE offset
+  .byte 48                              # Attributes: FUNCTION, EXTERNAL
+  .asciz  "hello"                         # External Name
+  .long 0                               # End Mark
+.LpubNames_end0:
+  .section  .debug_gnu_pubtypes,"",@progbits
+  .long .LpubTypes_end0-.LpubTypes_begin0 # Length of Public Types Info
+.LpubTypes_begin0:
+  .short  2                               # DWARF Version
+  .long .Lcu_begin0                     # Offset of Compilation Unit Info
+  .long 48                              # Compilation Unit Length
+  .long 0                               # End Mark
+.LpubTypes_end0:
+  .ident  "clang version 11.1.0 (https://github.com/llvm/llvm-project.git 173544ee3d09cdce8665f2097f677c31e1f1a9a1)"
+  .section  ".note.GNU-stack","",@progbits
+  .addrsig
+  .addrsig_sym printf
+  .section  .debug_line,"",@progbits
+.Lline_table_start0:
 No newline at end of file

llvm/test/tools/llvm-dwp/Inputs/overflow/debug_info_v5.s

+# Note: This file is compiled from the following code, for 
+#     the purpose of creating an overflowed dwo section.
+#       After being compiled from source, section `.debug_info.dwo`
+#       is changed to have length (2^32 - 30) Bytes, and added 
+#       padding with `.fill` directive, so it is likely to 
+#       overflow when packed with other files.
+# 
+# clang -g -S -gsplit-dwarf -gdwarf-5 hello.c
+#
+# #include <stdio.h>
+# void hello() {
+#     printf("hello\n");
+# }
+
+  .text
+  .file "hello.c"
+  .globl  hello                           # -- Begin function hello
+  .p2align  4, 0x90
+  .type hello,@function
+hello:                                  # @hello
+.Lfunc_begin0:
+  .file 0 "/xxxx/xxxxxxxxxx/xxxxxxxx/hello" "hello.c" md5 0x0b447232502f439981a2fe9f11255f42
+  .loc  0 3 0                           # hello.c:3:0
+  .cfi_startproc
+# %bb.0:                                # %entry
+  pushq %rbp
+  .cfi_def_cfa_offset 16
+  .cfi_offset %rbp, -16
+  movq  %rsp, %rbp
+  .cfi_def_cfa_register %rbp
+.Ltmp0:
+  .loc  0 4 5 prologue_end              # hello.c:4:5
+  movabsq $.L.str, %rdi
+  movb  $0, %al
+  callq printf
+  .loc  0 5 1                           # hello.c:5:1
+  popq  %rbp
+  .cfi_def_cfa %rsp, 8
+  retq
+.Ltmp1:
+.Lfunc_end0:
+  .size hello, .Lfunc_end0-hello
+  .cfi_endproc
+                                        # -- End function
+  .type .L.str,@object                  # @.str
+  .section  .rodata.str1.1,"aMS",@progbits,1
+.L.str:
+  .asciz  "hello\n"
+  .size .L.str, 7
+
+  .section  .debug_abbrev,"",@progbits
+  .byte 1                               # Abbreviation Code
+  .byte 74                              # DW_TAG_skeleton_unit
+  .byte 0                               # DW_CHILDREN_no
+  .byte 16                              # DW_AT_stmt_list
+  .byte 23                              # DW_FORM_sec_offset
+  .byte 114                             # DW_AT_str_offsets_base
+  .byte 23                              # DW_FORM_sec_offset
+  .byte 27                              # DW_AT_comp_dir
+  .byte 37                              # DW_FORM_strx1
+  .ascii  "\264B"                         # DW_AT_GNU_pubnames
+  .byte 25                              # DW_FORM_flag_present
+  .byte 118                             # DW_AT_dwo_name
+  .byte 37                              # DW_FORM_strx1
+  .byte 17                              # DW_AT_low_pc
+  .byte 27                              # DW_FORM_addrx
+  .byte 18                              # DW_AT_high_pc
+  .byte 6                               # DW_FORM_data4
+  .byte 115                             # DW_AT_addr_base
+  .byte 23                              # DW_FORM_sec_offset
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 0                               # EOM(3)
+  .section  .debug_info,"",@progbits
+.Lcu_begin0:
+  .long .Ldebug_info_end0-.Ldebug_info_start0 # Length of Unit
+.Ldebug_info_start0:
+  .short  5                               # DWARF version number
+  .byte 4                               # DWARF Unit Type
+  .byte 8                               # Address Size (in bytes)
+  .long .debug_abbrev                   # Offset Into Abbrev. Section
+  .quad -94954012350180462
+  .byte 1                               # Abbrev [1] 0x14:0x14 DW_TAG_skeleton_unit
+  .long .Lline_table_start0             # DW_AT_stmt_list
+  .long .Lstr_offsets_base0             # DW_AT_str_offsets_base
+  .byte 0                               # DW_AT_comp_dir
+                                        # DW_AT_GNU_pubnames
+  .byte 1                               # DW_AT_dwo_name
+  .byte 0                               # DW_AT_low_pc
+  .long .Lfunc_end0-.Lfunc_begin0       # DW_AT_high_pc
+  .long .Laddr_table_base0              # DW_AT_addr_base
+.Ldebug_info_end0:
+  .section  .debug_str_offsets,"",@progbits
+  .long 12
+  .short  5
+  .short  0
+.Lstr_offsets_base0:
+  .section  .debug_str,"MS",@progbits,1
+.Lskel_string0:
+  .asciz  "/xxxx/xxxxxxxxxx/xxxxxxxx/hello" # string offset=0
+.Lskel_string1:
+  .asciz  "hello.dwo"                     # string offset=32
+  .section  .debug_str_offsets,"",@progbits
+  .long .Lskel_string0
+  .long .Lskel_string1
+  .section  .debug_str_offsets.dwo,"e",@progbits
+  .long 20
+  .short  5
+  .short  0
+  .section  .debug_str.dwo,"eMS",@progbits,1
+.Linfo_string0:
+  .asciz  "hello"                         # string offset=0
+.Linfo_string1:
+  .asciz  "clang version 11.1.0 (https://github.com/llvm/llvm-project.git 1a0dc1e010bf5c8034bd4a53340fc0dc3e90549a)" # string offset=6
+.Linfo_string2:
+  .asciz  "hello.c"                       # string offset=111
+.Linfo_string3:
+  .asciz  "hello.dwo"                     # string offset=119
+  .section  .debug_str_offsets.dwo,"e",@progbits
+  .long 0
+  .long 6
+  .long 111
+  .long 119
+  .section  .debug_info.dwo,"e",@progbits
+  .long .Ldebug_info_dwo_end0-.Ldebug_info_dwo_start0 # Length of Unit
+.Ldebug_info_dwo_start0:
+  .short  5                               # DWARF version number
+  .byte 5                               # DWARF Unit Type
+  .byte 8                               # Address Size (in bytes)
+  .long 0                               # Offset Into Abbrev. Section
+  .quad -94954012350180462
+  .byte 1                               # Abbrev [1] 0x14:0x12 DW_TAG_compile_unit
+  .byte 1                               # DW_AT_producer
+  .short  12                              # DW_AT_language
+  .byte 2                               # DW_AT_name
+  .byte 3                               # DW_AT_dwo_name
+  .byte 2                               # Abbrev [2] 0x1a:0xb DW_TAG_subprogram
+  .byte 0                               # DW_AT_low_pc
+  .long .Lfunc_end0-.Lfunc_begin0       # DW_AT_high_pc
+  .byte 1                               # DW_AT_frame_base
+  .byte 86
+  .byte 0                               # DW_AT_name
+  .byte 0                               # DW_AT_decl_file
+  .byte 3                               # DW_AT_decl_line
+                                        # DW_AT_external
+  .byte 0                               # End Of Children Mark
+  .fill   4294967233
+.Ldebug_info_dwo_end0:
+  .section  .debug_abbrev.dwo,"e",@progbits
+  .byte 1                               # Abbreviation Code
+  .byte 17                              # DW_TAG_compile_unit
+  .byte 1                               # DW_CHILDREN_yes
+  .byte 37                              # DW_AT_producer
+  .byte 37                              # DW_FORM_strx1
+  .byte 19                              # DW_AT_language
+  .byte 5                               # DW_FORM_data2
+  .byte 3                               # DW_AT_name
+  .byte 37                              # DW_FORM_strx1
+  .byte 118                             # DW_AT_dwo_name
+  .byte 37                              # DW_FORM_strx1
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 2                               # Abbreviation Code
+  .byte 46                              # DW_TAG_subprogram
+  .byte 0                               # DW_CHILDREN_no
+  .byte 17                              # DW_AT_low_pc
+  .byte 27                              # DW_FORM_addrx
+  .byte 18                              # DW_AT_high_pc
+  .byte 6                               # DW_FORM_data4
+  .byte 64                              # DW_AT_frame_base
+  .byte 24                              # DW_FORM_exprloc
+  .byte 3                               # DW_AT_name
+  .byte 37                              # DW_FORM_strx1
+  .byte 58                              # DW_AT_decl_file
+  .byte 11                              # DW_FORM_data1
+  .byte 59                              # DW_AT_decl_line
+  .byte 11                              # DW_FORM_data1
+  .byte 63                              # DW_AT_external
+  .byte 25                              # DW_FORM_flag_present
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 0                               # EOM(3)
+  .section  .debug_addr,"",@progbits
+  .long .Ldebug_addr_end0-.Ldebug_addr_start0 # Length of contribution
+.Ldebug_addr_start0:
+  .short  5                               # DWARF version number
+  .byte 8                               # Address size
+  .byte 0                               # Segment selector size
+.Laddr_table_base0:
+  .quad .Lfunc_begin0
+.Ldebug_addr_end0:
+  .section  .debug_gnu_pubnames,"",@progbits
+  .long .LpubNames_end0-.LpubNames_begin0 # Length of Public Names Info
+.LpubNames_begin0:
+  .short  2                               # DWARF Version
+  .long .Lcu_begin0                     # Offset of Compilation Unit Info
+  .long 40                              # Compilation Unit Length
+  .long 26                              # DIE offset
+  .byte 48                              # Attributes: FUNCTION, EXTERNAL
+  .asciz  "hello"                         # External Name
+  .long 0                               # End Mark
+.LpubNames_end0:
+  .section  .debug_gnu_pubtypes,"",@progbits
+  .long .LpubTypes_end0-.LpubTypes_begin0 # Length of Public Types Info
+.LpubTypes_begin0:
+  .short  2                               # DWARF Version
+  .long .Lcu_begin0                     # Offset of Compilation Unit Info
+  .long 40                              # Compilation Unit Length
+  .long 0                               # End Mark
+.LpubTypes_end0:
+  .ident  "clang version 11.1.0 (https://github.com/llvm/llvm-project.git 1a0dc1e010bf5c8034bd4a53340fc0dc3e90549a)"
+  .section  ".note.GNU-stack","",@progbits
+  .addrsig
+  .addrsig_sym printf
+  .section  .debug_line,"",@progbits
+.Lline_table_start0:

llvm/test/tools/llvm-dwp/Inputs/overflow/main_v4.s

+# Note: This file is compiled from the following code, for 
+#     the purpose of creating an overflowed dwo section.
+#       The code is not further modified after being compiled.
+# 
+# clang -g -S -gsplit-dwarf -gdwarf-4 main.c
+#
+# #include <stdio.h>
+# 
+# void hello();
+# 
+# int main() {
+#     hello();
+#     return 0;
+# }
+
+  .text
+  .file "main.c"
+  .globl  main                            # -- Begin function main
+  .p2align  4, 0x90
+  .type main,@function
+main:                                   # @main
+.Lfunc_begin0:
+  .file 1 "/xxxxxx/xxxx/xxxxxxxxxx/xxxxxxxx/hello" "main.c"
+  .loc  1 5 0                           # main.c:5:0
+  .cfi_startproc
+# %bb.0:
+  pushq %rbp
+  .cfi_def_cfa_offset 16
+  .cfi_offset %rbp, -16
+  movq  %rsp, %rbp
+  .cfi_def_cfa_register %rbp
+  subq  $16, %rsp
+  movl  $0, -4(%rbp)
+.Ltmp0:
+  .loc  1 6 5 prologue_end              # main.c:6:5
+  movb  $0, %al
+  callq hello
+  xorl  %eax, %eax
+  .loc  1 7 5                           # main.c:7:5
+  addq  $16, %rsp
+  popq  %rbp
+  .cfi_def_cfa %rsp, 8
+  retq
+.Ltmp1:
+.Lfunc_end0:
+  .size main, .Lfunc_end0-main
+  .cfi_endproc
+                                        # -- End function
+  .section  .debug_abbrev,"",@progbits
+  .byte 1                               # Abbreviation Code
+  .byte 17                              # DW_TAG_compile_unit
+  .byte 0                               # DW_CHILDREN_no
+  .byte 16                              # DW_AT_stmt_list
+  .byte 23                              # DW_FORM_sec_offset
+  .byte 27                              # DW_AT_comp_dir
+  .byte 14                              # DW_FORM_strp
+  .ascii  "\264B"                         # DW_AT_GNU_pubnames
+  .byte 25                              # DW_FORM_flag_present
+  .ascii  "\260B"                         # DW_AT_GNU_dwo_name
+  .byte 14                              # DW_FORM_strp
+  .ascii  "\261B"                         # DW_AT_GNU_dwo_id
+  .byte 7                               # DW_FORM_data8
+  .byte 17                              # DW_AT_low_pc
+  .byte 1                               # DW_FORM_addr
+  .byte 18                              # DW_AT_high_pc
+  .byte 6                               # DW_FORM_data4
+  .ascii  "\263B"                         # DW_AT_GNU_addr_base
+  .byte 23                              # DW_FORM_sec_offset
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 0                               # EOM(3)
+  .section  .debug_info,"",@progbits
+.Lcu_begin0:
+  .long .Ldebug_info_end0-.Ldebug_info_start0 # Length of Unit
+.Ldebug_info_start0:
+  .short  4                               # DWARF version number
+  .long .debug_abbrev                   # Offset Into Abbrev. Section
+  .byte 8                               # Address Size (in bytes)
+  .byte 1                               # Abbrev [1] 0xb:0x25 DW_TAG_compile_unit
+  .long .Lline_table_start0             # DW_AT_stmt_list
+  .long .Lskel_string0                  # DW_AT_comp_dir
+                                        # DW_AT_GNU_pubnames
+  .long .Lskel_string1                  # DW_AT_GNU_dwo_name
+  .quad -346972125991005518             # DW_AT_GNU_dwo_id
+  .quad .Lfunc_begin0                   # DW_AT_low_pc
+  .long .Lfunc_end0-.Lfunc_begin0       # DW_AT_high_pc
+  .long .Laddr_table_base0              # DW_AT_GNU_addr_base
+.Ldebug_info_end0:
+  .section  .debug_str,"MS",@progbits,1
+.Lskel_string0:
+  .asciz  "/xxxxxx/xxxx/xxxxxxxxxx/xxxxxxxx/hello" # string offset=0
+.Lskel_string1:
+  .asciz  "main.dwo"                      # string offset=39
+  .section  .debug_str.dwo,"eMS",@progbits,1
+.Linfo_string0:
+  .asciz  "main"                          # string offset=0
+.Linfo_string1:
+  .asciz  "int"                           # string offset=5
+.Linfo_string2:
+  .asciz  "clang version 11.1.0 (https://github.com/llvm/llvm-project.git ed8f312fb1ca0bf525676906c7841db0cefcf5a7)" # string offset=9
+.Linfo_string3:
+  .asciz  "main.c"                        # string offset=114
+.Linfo_string4:
+  .asciz  "main.dwo"                      # string offset=121
+  .section  .debug_str_offsets.dwo,"e",@progbits
+  .long 0
+  .long 5
+  .long 9
+  .long 114
+  .long 121
+  .section  .debug_info.dwo,"e",@progbits
+  .long .Ldebug_info_dwo_end0-.Ldebug_info_dwo_start0 # Length of Unit
+.Ldebug_info_dwo_start0:
+  .short  4                               # DWARF version number
+  .long 0                               # Offset Into Abbrev. Section
+  .byte 8                               # Address Size (in bytes)
+  .byte 1                               # Abbrev [1] 0xb:0x22 DW_TAG_compile_unit
+  .byte 2                               # DW_AT_producer
+  .short  12                              # DW_AT_language
+  .byte 3                               # DW_AT_name
+  .byte 4                               # DW_AT_GNU_dwo_name
+  .quad -346972125991005518             # DW_AT_GNU_dwo_id
+  .byte 2                               # Abbrev [2] 0x19:0xf DW_TAG_subprogram
+  .byte 0                               # DW_AT_low_pc
+  .long .Lfunc_end0-.Lfunc_begin0       # DW_AT_high_pc
+  .byte 1                               # DW_AT_frame_base
+  .byte 86
+  .byte 0                               # DW_AT_name
+  .byte 1                               # DW_AT_decl_file
+  .byte 5                               # DW_AT_decl_line
+  .long 40                              # DW_AT_type
+                                        # DW_AT_external
+  .byte 3                               # Abbrev [3] 0x28:0x4 DW_TAG_base_type
+  .byte 1                               # DW_AT_name
+  .byte 5                               # DW_AT_encoding
+  .byte 4                               # DW_AT_byte_size
+  .byte 0                               # End Of Children Mark
+.Ldebug_info_dwo_end0:
+  .section  .debug_abbrev.dwo,"e",@progbits
+  .byte 1                               # Abbreviation Code
+  .byte 17                              # DW_TAG_compile_unit
+  .byte 1                               # DW_CHILDREN_yes
+  .byte 37                              # DW_AT_producer
+  .ascii  "\202>"                         # DW_FORM_GNU_str_index
+  .byte 19                              # DW_AT_language
+  .byte 5                               # DW_FORM_data2
+  .byte 3                               # DW_AT_name
+  .ascii  "\202>"                         # DW_FORM_GNU_str_index
+  .ascii  "\260B"                         # DW_AT_GNU_dwo_name
+  .ascii  "\202>"                         # DW_FORM_GNU_str_index
+  .ascii  "\261B"                         # DW_AT_GNU_dwo_id
+  .byte 7                               # DW_FORM_data8
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 2                               # Abbreviation Code
+  .byte 46                              # DW_TAG_subprogram
+  .byte 0                               # DW_CHILDREN_no
+  .byte 17                              # DW_AT_low_pc
+  .ascii  "\201>"                         # DW_FORM_GNU_addr_index
+  .byte 18                              # DW_AT_high_pc
+  .byte 6                               # DW_FORM_data4
+  .byte 64                              # DW_AT_frame_base
+  .byte 24                              # DW_FORM_exprloc
+  .byte 3                               # DW_AT_name
+  .ascii  "\202>"                         # DW_FORM_GNU_str_index
+  .byte 58                              # DW_AT_decl_file
+  .byte 11                              # DW_FORM_data1
+  .byte 59                              # DW_AT_decl_line
+  .byte 11                              # DW_FORM_data1
+  .byte 73                              # DW_AT_type
+  .byte 19                              # DW_FORM_ref4
+  .byte 63                              # DW_AT_external
+  .byte 25                              # DW_FORM_flag_present
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 3                               # Abbreviation Code
+  .byte 36                              # DW_TAG_base_type
+  .byte 0                               # DW_CHILDREN_no
+  .byte 3                               # DW_AT_name
+  .ascii  "\202>"                         # DW_FORM_GNU_str_index
+  .byte 62                              # DW_AT_encoding
+  .byte 11                              # DW_FORM_data1
+  .byte 11                              # DW_AT_byte_size
+  .byte 11                              # DW_FORM_data1
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 0                               # EOM(3)
+  .section  .debug_addr,"",@progbits
+.Laddr_table_base0:
+  .quad .Lfunc_begin0
+  .section  .debug_gnu_pubnames,"",@progbits
+  .long .LpubNames_end0-.LpubNames_begin0 # Length of Public Names Info
+.LpubNames_begin0:
+  .short  2                               # DWARF Version
+  .long .Lcu_begin0                     # Offset of Compilation Unit Info
+  .long 48                              # Compilation Unit Length
+  .long 25                              # DIE offset
+  .byte 48                              # Attributes: FUNCTION, EXTERNAL
+  .asciz  "main"                          # External Name
+  .long 0                               # End Mark
+.LpubNames_end0:
+  .section  .debug_gnu_pubtypes,"",@progbits
+  .long .LpubTypes_end0-.LpubTypes_begin0 # Length of Public Types Info
+.LpubTypes_begin0:
+  .short  2                               # DWARF Version
+  .long .Lcu_begin0                     # Offset of Compilation Unit Info
+  .long 48                              # Compilation Unit Length
+  .long 40                              # DIE offset
+  .byte 144                             # Attributes: TYPE, STATIC
+  .asciz  "int"                           # External Name
+  .long 0                               # End Mark
+.LpubTypes_end0:
+  .ident  "clang version 11.1.0 (https://github.com/llvm/llvm-project.git ed8f312fb1ca0bf525676906c7841db0cefcf5a7)"
+  .section  ".note.GNU-stack","",@progbits
+  .addrsig
+  .addrsig_sym hello
+  .section  .debug_line,"",@progbits
+.Lline_table_start0:
 No newline at end of file

llvm/test/tools/llvm-dwp/Inputs/overflow/main_v5.s

+# Note: This file is compiled from the following code, for 
+#     the purpose of creating an overflowed dwo section.
+#       The code is not further modified after being compiled.
+# 
+# clang -g -S -gsplit-dwarf -gdwarf-5 main.c
+#
+# #include <stdio.h>
+# 
+# void hello();
+# 
+# int main() {
+#     hello();
+#     return 0;
+# }
+
+  .text
+  .file "main.c"
+  .globl  main                            # -- Begin function main
+  .p2align  4, 0x90
+  .type main,@function
+main:                                   # @main
+.Lfunc_begin0:
+  .file 0 "/xxxx/xxxxxxxxxx/xxxxxxxx/hello" "main.c" md5 0x77ee8a574e83e137b0f31f877848b7ec
+  .loc  0 5 0                           # main.c:5:0
+  .cfi_startproc
+# %bb.0:                                # %entry
+  pushq %rbp
+  .cfi_def_cfa_offset 16
+  .cfi_offset %rbp, -16
+  movq  %rsp, %rbp
+  .cfi_def_cfa_register %rbp
+  subq  $16, %rsp
+  movl  $0, -4(%rbp)
+.Ltmp0:
+  .loc  0 6 5 prologue_end              # main.c:6:5
+  movb  $0, %al
+  callq hello
+  xorl  %eax, %eax
+  .loc  0 7 5                           # main.c:7:5
+  addq  $16, %rsp
+  popq  %rbp
+  .cfi_def_cfa %rsp, 8
+  retq
+.Ltmp1:
+.Lfunc_end0:
+  .size main, .Lfunc_end0-main
+  .cfi_endproc
+                                        # -- End function
+  .section  .debug_abbrev,"",@progbits
+  .byte 1                               # Abbreviation Code
+  .byte 74                              # DW_TAG_skeleton_unit
+  .byte 0                               # DW_CHILDREN_no
+  .byte 16                              # DW_AT_stmt_list
+  .byte 23                              # DW_FORM_sec_offset
+  .byte 114                             # DW_AT_str_offsets_base
+  .byte 23                              # DW_FORM_sec_offset
+  .byte 27                              # DW_AT_comp_dir
+  .byte 37                              # DW_FORM_strx1
+  .ascii  "\264B"                         # DW_AT_GNU_pubnames
+  .byte 25                              # DW_FORM_flag_present
+  .byte 118                             # DW_AT_dwo_name
+  .byte 37                              # DW_FORM_strx1
+  .byte 17                              # DW_AT_low_pc
+  .byte 27                              # DW_FORM_addrx
+  .byte 18                              # DW_AT_high_pc
+  .byte 6                               # DW_FORM_data4
+  .byte 115                             # DW_AT_addr_base
+  .byte 23                              # DW_FORM_sec_offset
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 0                               # EOM(3)
+  .section  .debug_info,"",@progbits
+.Lcu_begin0:
+  .long .Ldebug_info_end0-.Ldebug_info_start0 # Length of Unit
+.Ldebug_info_start0:
+  .short  5                               # DWARF version number
+  .byte 4                               # DWARF Unit Type
+  .byte 8                               # Address Size (in bytes)
+  .long .debug_abbrev                   # Offset Into Abbrev. Section
+  .quad -346972125991005518
+  .byte 1                               # Abbrev [1] 0x14:0x14 DW_TAG_skeleton_unit
+  .long .Lline_table_start0             # DW_AT_stmt_list
+  .long .Lstr_offsets_base0             # DW_AT_str_offsets_base
+  .byte 0                               # DW_AT_comp_dir
+                                        # DW_AT_GNU_pubnames
+  .byte 1                               # DW_AT_dwo_name
+  .byte 0                               # DW_AT_low_pc
+  .long .Lfunc_end0-.Lfunc_begin0       # DW_AT_high_pc
+  .long .Laddr_table_base0              # DW_AT_addr_base
+.Ldebug_info_end0:
+  .section  .debug_str_offsets,"",@progbits
+  .long 12
+  .short  5
+  .short  0
+.Lstr_offsets_base0:
+  .section  .debug_str,"MS",@progbits,1
+.Lskel_string0:
+  .asciz  "/xxxx/xxxxxxxxxx/xxxxxxxx/hello" # string offset=0
+.Lskel_string1:
+  .asciz  "main.dwo"                      # string offset=32
+  .section  .debug_str_offsets,"",@progbits
+  .long .Lskel_string0
+  .long .Lskel_string1
+  .section  .debug_str_offsets.dwo,"e",@progbits
+  .long 24
+  .short  5
+  .short  0
+  .section  .debug_str.dwo,"eMS",@progbits,1
+.Linfo_string0:
+  .asciz  "main"                          # string offset=0
+.Linfo_string1:
+  .asciz  "int"                           # string offset=5
+.Linfo_string2:
+  .asciz  "clang version 11.1.0 (https://github.com/llvm/llvm-project.git 1a0dc1e010bf5c8034bd4a53340fc0dc3e90549a)" # string offset=9
+.Linfo_string3:
+  .asciz  "main.c"                        # string offset=114
+.Linfo_string4:
+  .asciz  "main.dwo"                      # string offset=121
+  .section  .debug_str_offsets.dwo,"e",@progbits
+  .long 0
+  .long 5
+  .long 9
+  .long 114
+  .long 121
+  .section  .debug_info.dwo,"e",@progbits
+  .long .Ldebug_info_dwo_end0-.Ldebug_info_dwo_start0 # Length of Unit
+.Ldebug_info_dwo_start0:
+  .short  5                               # DWARF version number
+  .byte 5                               # DWARF Unit Type
+  .byte 8                               # Address Size (in bytes)
+  .long 0                               # Offset Into Abbrev. Section
+  .quad -346972125991005518
+  .byte 1                               # Abbrev [1] 0x14:0x1a DW_TAG_compile_unit
+  .byte 2                               # DW_AT_producer
+  .short  12                              # DW_AT_language
+  .byte 3                               # DW_AT_name
+  .byte 4                               # DW_AT_dwo_name
+  .byte 2                               # Abbrev [2] 0x1a:0xf DW_TAG_subprogram
+  .byte 0                               # DW_AT_low_pc
+  .long .Lfunc_end0-.Lfunc_begin0       # DW_AT_high_pc
+  .byte 1                               # DW_AT_frame_base
+  .byte 86
+  .byte 0                               # DW_AT_name
+  .byte 0                               # DW_AT_decl_file
+  .byte 5                               # DW_AT_decl_line
+  .long 41                              # DW_AT_type
+                                        # DW_AT_external
+  .byte 3                               # Abbrev [3] 0x29:0x4 DW_TAG_base_type
+  .byte 1                               # DW_AT_name
+  .byte 5                               # DW_AT_encoding
+  .byte 4                               # DW_AT_byte_size
+  .byte 0                               # End Of Children Mark
+  .fill   4294967233
+.Ldebug_info_dwo_end0:
+  .section  .debug_abbrev.dwo,"e",@progbits
+  .byte 1                               # Abbreviation Code
+  .byte 17                              # DW_TAG_compile_unit
+  .byte 1                               # DW_CHILDREN_yes
+  .byte 37                              # DW_AT_producer
+  .byte 37                              # DW_FORM_strx1
+  .byte 19                              # DW_AT_language
+  .byte 5                               # DW_FORM_data2
+  .byte 3                               # DW_AT_name
+  .byte 37                              # DW_FORM_strx1
+  .byte 118                             # DW_AT_dwo_name
+  .byte 37                              # DW_FORM_strx1
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 2                               # Abbreviation Code
+  .byte 46                              # DW_TAG_subprogram
+  .byte 0                               # DW_CHILDREN_no
+  .byte 17                              # DW_AT_low_pc
+  .byte 27                              # DW_FORM_addrx
+  .byte 18                              # DW_AT_high_pc
+  .byte 6                               # DW_FORM_data4
+  .byte 64                              # DW_AT_frame_base
+  .byte 24                              # DW_FORM_exprloc
+  .byte 3                               # DW_AT_name
+  .byte 37                              # DW_FORM_strx1
+  .byte 58                              # DW_AT_decl_file
+  .byte 11                              # DW_FORM_data1
+  .byte 59                              # DW_AT_decl_line
+  .byte 11                              # DW_FORM_data1
+  .byte 73                              # DW_AT_type
+  .byte 19                              # DW_FORM_ref4
+  .byte 63                              # DW_AT_external
+  .byte 25                              # DW_FORM_flag_present
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 3                               # Abbreviation Code
+  .byte 36                              # DW_TAG_base_type
+  .byte 0                               # DW_CHILDREN_no
+  .byte 3                               # DW_AT_name
+  .byte 37                              # DW_FORM_strx1
+  .byte 62                              # DW_AT_encoding
+  .byte 11                              # DW_FORM_data1
+  .byte 11                              # DW_AT_byte_size
+  .byte 11                              # DW_FORM_data1
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 0                               # EOM(3)
+  .section  .debug_addr,"",@progbits
+  .long .Ldebug_addr_end0-.Ldebug_addr_start0 # Length of contribution
+.Ldebug_addr_start0:
+  .short  5                               # DWARF version number
+  .byte 8                               # Address size
+  .byte 0                               # Segment selector size
+.Laddr_table_base0:
+  .quad .Lfunc_begin0
+.Ldebug_addr_end0:
+  .section  .debug_gnu_pubnames,"",@progbits
+  .long .LpubNames_end0-.LpubNames_begin0 # Length of Public Names Info
+.LpubNames_begin0:
+  .short  2                               # DWARF Version
+  .long .Lcu_begin0                     # Offset of Compilation Unit Info
+  .long 40                              # Compilation Unit Length
+  .long 26                              # DIE offset
+  .byte 48                              # Attributes: FUNCTION, EXTERNAL
+  .asciz  "main"                          # External Name
+  .long 0                               # End Mark
+.LpubNames_end0:
+  .section  .debug_gnu_pubtypes,"",@progbits
+  .long .LpubTypes_end0-.LpubTypes_begin0 # Length of Public Types Info
+.LpubTypes_begin0:
+  .short  2                               # DWARF Version
+  .long .Lcu_begin0                     # Offset of Compilation Unit Info
+  .long 40                              # Compilation Unit Length
+  .long 41                              # DIE offset
+  .byte 144                             # Attributes: TYPE, STATIC
+  .asciz  "int"                           # External Name
+  .long 0                               # End Mark
+.LpubTypes_end0:
+  .ident  "clang version 11.1.0 (https://github.com/llvm/llvm-project.git 1a0dc1e010bf5c8034bd4a53340fc0dc3e90549a)"
+  .section  ".note.GNU-stack","",@progbits
+  .addrsig
+  .addrsig_sym hello
+  .section  .debug_line,"",@progbits
+.Lline_table_start0:

llvm/test/tools/llvm-dwp/X86/overflow_debug_info_v4.test.manual

+RUN: llvm-mc --triple=x86_64-unknown-linux --filetype=obj --split-dwarf-file=debug_info_v4.dwo -dwarf-version=4 %p/../Inputs/overflow/debug_info_v4.s -o debug_info_v4.o
+RUN: llvm-mc --triple=x86_64-unknown-linux --filetype=obj --split-dwarf-file=main_v4.dwo -dwarf-version=4 %p/../Inputs/overflow/main_v4.s -o main_v4.o
+RUN: not llvm-dwp debug_info_v4.dwo main_v4.dwo -o overflow.dwp 2>&1 | FileCheck %s
+CHECK: error: {{.*}} Section Contribution Offset overflow 4G. Previous Offset {{.*}}, After overflow offset {{.*}}.

llvm/test/tools/llvm-dwp/X86/overflow_debug_info_v5.test.manual

+RUN: llvm-mc --triple=x86_64-unknown-linux --filetype=obj --split-dwarf-file=debug_info_v5.dwo -dwarf-version=5 %p/../Inputs/overflow/debug_info_v5.s -o debug_info_v5.o
+RUN: llvm-mc --triple=x86_64-unknown-linux --filetype=obj --split-dwarf-file=main_v5.dwo -dwarf-version=5 %p/../Inputs/overflow/main_v5.s -o main_v5.o
+RUN: not llvm-dwp debug_info_v5.dwo main_v5.dwo -o overflow.dwp 2>&1 | FileCheck %s
+CHECK: error: {{.*}} Section Contribution Offset overflow 4G. Previous Offset {{.*}}, After overflow offset {{.*}}.

llvm/test/tools/llvm-dwp/X86/overflow_debug_info_warning_v4.test.manual

+RUN: llvm-mc --triple=x86_64-unknown-linux --filetype=obj --split-dwarf-file=debug_info_v4.dwo -dwarf-version=4 %p/../Inputs/overflow/debug_info_v4.s -o debug_info_v4.o
+RUN: llvm-mc --triple=x86_64-unknown-linux --filetype=obj --split-dwarf-file=main_v4.dwo -dwarf-version=4 %p/../Inputs/overflow/main_v4.s -o main_v4.o
+RUN: llvm-dwp debug_info_v4.dwo main_v4.dwo -continue-on-cu-index-overflow -o overflow_v4.dwp 2>&1 | FileCheck %s
+RUN: llvm-dwp overflow_v4.dwp -o overflow_warned_v4.dwp
+CHECK: warning: {{.*}} Section Contribution Offset overflow 4G. Previous Offset {{.*}}, After overflow offset {{.*}}.

llvm/test/tools/llvm-dwp/X86/overflow_debug_info_warning_v5.test.manual

+RUN: llvm-mc --triple=x86_64-unknown-linux --filetype=obj --split-dwarf-file=debug_info_v5.dwo -dwarf-version=5 %p/../Inputs/overflow/debug_info_v5.s -o debug_info_v5.o
+RUN: llvm-mc --triple=x86_64-unknown-linux --filetype=obj --split-dwarf-file=main_v5.dwo -dwarf-version=5 %p/../Inputs/overflow/main_v5.s -o main_v5.o
+RUN: llvm-dwp debug_info_v5.dwo main_v5.dwo -continue-on-cu-index-overflow -o overflow_v5.dwp 2>&1 | FileCheck %s
+RUN: llvm-dwp overflow_v5.dwp -o overflow_warned_v5.dwp
+CHECK: warning: {{.*}} Section Contribution Offset overflow 4G. Previous Offset {{.*}}, After overflow offset {{.*}}.

llvm/tools/llvm-dwp/llvm-dwp.cpp

static cl::list<std::string> ExecFilenames(
     cl::desc(
         "Specify the executable/library files to get the list of *.dwo from"),
     cl::value_desc("filename"), cl::cat(DwpCategory));
 
 static cl::opt<std::string> OutputFilename(cl::Required, "o",
                                            cl::desc("Specify the output file."),
                                            cl::value_desc("filename"),
                                            cl::cat(DwpCategory));
 
+static cl::opt<bool> ContinueOnCuIndexOverflow(
+    "continue-on-cu-index-overflow",
+    cl::desc("This turns an error when offset for .debug_*.dwo sections "
+             "overfolws into a warning."),
+    cl::cat(DwpCategory));
+
 static Expected<SmallVector<std::string, 16>>
 getDWOFilenames(StringRef ExecFilename) {
   auto ErrOrObj = object::ObjectFile::createObjectFile(ExecFilename);
   if (!ErrOrObj)
     return ErrOrObj.takeError();
 
   const ObjectFile &Obj = *ErrOrObj.get().getBinary();
   std::unique_ptr<DWARFContext> DWARFCtx = DWARFContext::create(Obj);
 
   SmallVector<std::string, 16> DWOPaths;
   for (const auto &CU : DWARFCtx->compile_units()) {
     const DWARFDie &Die = CU->getUnitDIE();
int main(int argc, char **argv) {
   std::unique_ptr<MCStreamer> MS(TheTarget->createMCObjectStreamer(
       *ErrOrTriple, MC, std::unique_ptr<MCAsmBackend>(MAB),
       MAB->createObjectWriter(*OS), std::unique_ptr<MCCodeEmitter>(MCE), *MSTI,
       MCOptions.MCRelaxAll, MCOptions.MCIncrementalLinkerCompatible,
       /*DWARFMustBeAtTheEnd*/ false));
   if (!MS)
     return error("no object streamer for target " + TripleName, Context);
 
-  if (auto Err = write(*MS, DWOFilenames)) {
+  if (auto Err = write(*MS, DWOFilenames, ContinueOnCuIndexOverflow)) {
     logAllUnhandledErrors(std::move(Err), WithColor::error());
     return 1;
   }
 
   MS->finish();
   OutFile.keep();
   return 0;
 }