dwp section overflow checks

[dblaikie]

Summary

This is a rebase to main branch of https://reviews.llvm.org/D144565. In addition to that patch, I added another test, checking debug_str section.

[ayermolo]

This comment was removed by ayermolo.

[dblaikie]

I'm a bit confused - wasn't D144565 already committed? What's this then? Should this patch be abandoned now?

llvm/lib/DWP/DWP.cpp

722–724

(prefer = init over () init where both are valid, the former doesn't allow implicit conversions while the latter does - so seeing = can be easier to read because there's no explicit conversions (which can be more complicated/nuanced) to worry about) - and prefer declaring the variable in the smallest scope, including in the if condition where possible)

[zhuna8616]

Yes. This one should be abandoned.

llvm/lib/DWP/DWP.cpp

 #include "llvm/DWP/DWP.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/MemoryBuffer.h"
+#include "llvm/Support/CommandLine.h"
 #include <limits>
 
 using namespace llvm;
 using namespace llvm::object;
 
 static mc::RegisterMCTargetOptionsFlags MCTargetOptionsFlags;
 
+extern cl::OptionCategory 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));
+
 // Returns the size of debug_str_offsets section headers in bytes.
 static uint64_t debugStrOffsetsHeaderSize(DataExtractor StrOffsetsData,
                                           uint16_t DwarfVersion) {
   if (DwarfVersion <= 4)
     return 0; // There is no header before dwarf 5.
   uint64_t Offset = 0;
   uint64_t Length = StrOffsetsData.getU32(&Offset);
   if (Length == llvm::dwarf::DW_LENGTH_DWARF64)
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
+static Error sectionOverflowErrorOrWarning(
+  uint32_t PrevOffset, uint32_t OverflowedOffset, 
+  StringRef SectionName) {
+  std::string Msg = SectionName.str() + std::string(" Section Contribution Offset overflow 4G. Previous Offset ")
+    + std::to_string(PrevOffset) + std::string(", After overflow offset ") 
+    + std::to_string(OverflowedOffset) + std::string(".");
+  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) {
   Out.switchSection(OutputTypes);
   for (const DWARFUnitIndex::Entry &E : TUIndex.getRows()) {
     auto *I = E.getContributions();
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;
     TypesOffset += C.getLength();
+    if (OldOffset > TypesOffset) {
+      Error Err (sectionOverflowErrorOrWarning(OldOffset, TypesOffset, "Types"));
+      if (Err) {
+        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) {
   for (StringRef Types : TypesSections) {
     Out.switchSection(OutputTypes);
     uint64_t Offset = 0;
     DataExtractor Data(Types, true, 0);
     while (Data.isValidOffset(Offset)) {
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) {
+        Error Err (sectionOverflowErrorOrWarning(OldOffset, TypesOffset, "types"));
+        if (Err) {
+          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();
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 (ContributionOffsets[Index] < OldOffset) {
+        uint32_t SectionIndex = 0;
+        for (auto &Section : Obj.sections()) {
+          if (SectionIndex == Index) {
+            return sectionOverflowErrorOrWarning(
+              OldOffset, ContributionOffsets[Index], *Section.getName());
+          }
+          ++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()) {
+            Error Err (sectionOverflowErrorOrWarning(
+              InfoSectionOffset, InfoSectionOffset + C.getLength32(), "debug_info"));
+            if (Err) {
+              return Err;
+            }
+          }
+            // return make_error<DWPError>(
+            //     "debug information section offset is greater than 4GB");
 
           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 (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.
+        Error Err = 
           addAllTypesFromTypesSection(
             Out, TypeIndexEntries, TypesSection, CurTypesSection, CurEntry,
             ContributionOffsets[getContributionIndex(DW_SECT_EXT_TYPES, 2)]);
+        if (Err) {
+          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,
+      Error Err = addAllTypesFromDWP(Out, TypeIndexEntries, TUIndex, OutSection,
                                     TypeInputSection, CurEntry,
                                     ContributionOffsets[TypesContributionIndex],
                                     TypesContributionIndex);
+      if (Err) {
+        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.s

+  .text
+  .file "hello.c"
+  .globl  hello                           # -- Begin function hello
+  .p2align  4, 0x90
+  .type hello,@function
+hello:                                  # @hello
+.Lfunc_begin0:
+  .file 1 "/data00/home/zhuna.1024/gdb-10.1/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  "/data00/home/zhuna.1024/gdb-10.1/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:

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

+  .text
+  .file "hello.c"
+  .globl  hello                           # -- Begin function hello
+  .p2align  4, 0x90
+  .type hello,@function
+hello:                                  # @hello
+.Lfunc_begin0:
+  .file 1 "/data00/home/zhuna.1024/gdb-10.1/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  "/data00/home/zhuna.1024/gdb-10.1/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
+.Lfill_string:                              # string offset=128
+  .fill   4294967266, 1, 1  # 2^32 - 30
+
+  .section  .debug_str_offsets.dwo,"e",@progbits
+  .long 0
+  .long 6
+  .long 111
+  .long 119
+  .long   128
+  .section  .debug_info.dwo,"e",@progbits
+  .long 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:

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

+  .text
+  .file "main.c"
+  .globl  main                            # -- Begin function main
+  .p2align  4, 0x90
+  .type main,@function
+main:                                   # @main
+.Lfunc_begin0:
+  .file 1 "/data00/home/zhuna.1024/gdb-10.1/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  "/data00/home/zhuna.1024/gdb-10.1/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:

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

+RUN: llvm-mc --triple=x86_64-unknown-linux --filetype=obj --split-dwarf-file=debug_info.dwo -dwarf-version=5 %p/../Inputs/overflow/debug_info.s -o debug_info.o
+RUN: llvm-mc --triple=x86_64-unknown-linux --filetype=obj --split-dwarf-file=main.dwo -dwarf-version=5 %p/../Inputs/overflow/main.s -o main.o
+RUN: not llvm-dwp -e debug_info.o -e main.o -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.test

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

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

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