[llvm] 9670a45 - libDebugInfoDWARF: Don't try to parse loclist[.dwo] headers when parsing debug_info[.dwo]
David Blaikie via llvm-commits
llvm-commits at lists.llvm.org
Tue Oct 13 22:34:32 PDT 2020
Author: David Blaikie
Date: 2020-10-13T22:28:59-07:00
New Revision: 9670a45c980c371c5ece8047a00b8b2abec73823
URL: https://github.com/llvm/llvm-project/commit/9670a45c980c371c5ece8047a00b8b2abec73823
DIFF: https://github.com/llvm/llvm-project/commit/9670a45c980c371c5ece8047a00b8b2abec73823.diff
LOG: libDebugInfoDWARF: Don't try to parse loclist[.dwo] headers when parsing debug_info[.dwo]
There's no way to know whether there's a loclist contribution to parse
if there's no loclistx encoding - and if there is one, there's no need
to walk back from the loclist_base (or, uin the case of
info.dwo/loclist.dwo - starting at 0 in the contribution) to parse the
header, instead rely on the DWARF32/64 and address size in the CU
that's already available.
This would come up in split DWARF (non-split wouldn't try to read a
loclist header in the absence of a loclist_base) when one unit had
location lists and another does not (because the loclists.dwo section
would be non-empty in that case - in the case where it's empty the
parsing would silently skip).
Simplify the testing a bit, rather than needing a whole dwp, etc - by
creating a malformed loclists.dwo section (and use single file Split
DWARF) that would trip up any attempt to parse it - but no attempt
should be made.
Added:
llvm/test/tools/llvm-dwarfdump/X86/debug_loclists_unused_invalid.s
Modified:
llvm/include/llvm/DebugInfo/DWARF/DWARFUnit.h
llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
Removed:
################################################################################
diff --git a/llvm/include/llvm/DebugInfo/DWARF/DWARFUnit.h b/llvm/include/llvm/DebugInfo/DWARF/DWARFUnit.h
index 0b0238f7235e..369cbdc28c2e 100644
--- a/llvm/include/llvm/DebugInfo/DWARF/DWARFUnit.h
+++ b/llvm/include/llvm/DebugInfo/DWARF/DWARFUnit.h
@@ -209,7 +209,6 @@ class DWARFUnit {
const DWARFDebugAbbrev *Abbrev;
const DWARFSection *RangeSection;
uint64_t RangeSectionBase;
- const DWARFSection *LocSection;
uint64_t LocSectionBase;
/// Location table of this unit.
@@ -228,9 +227,6 @@ class DWARFUnit {
/// offsets table (DWARF v5).
Optional<StrOffsetsContributionDescriptor> StringOffsetsTableContribution;
- /// A table of range lists (DWARF v5 and later).
- Optional<DWARFListTableHeader> LoclistTableHeader;
-
mutable const DWARFAbbreviationDeclarationSet *Abbrevs;
llvm::Optional<object::SectionedAddress> BaseAddr;
/// The compile unit debug information entry items.
@@ -318,10 +314,6 @@ class DWARFUnit {
RangeSection = RS;
RangeSectionBase = Base;
}
- void setLocSection(const DWARFSection *LS, uint64_t Base) {
- LocSection = LS;
- LocSectionBase = Base;
- }
uint64_t getLocSectionBase() const {
return LocSectionBase;
@@ -418,14 +410,8 @@ class DWARFUnit {
/// DW_FORM_rnglistx.
Optional<uint64_t> getRnglistOffset(uint32_t Index);
- Optional<uint64_t> getLoclistOffset(uint32_t Index) {
- if (!LoclistTableHeader)
- return None;
- if (Optional<uint64_t> Off =
- LoclistTableHeader->getOffsetEntry(LocTable->getData(), Index))
- return *Off + getLocSectionBase();
- return None;
- }
+ Optional<uint64_t> getLoclistOffset(uint32_t Index);
+
Expected<DWARFAddressRangesVector> collectAddressRanges();
Expected<DWARFLocationExpressionsVector>
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp b/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
index 67066db15b4a..ffd7d1e62c94 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
@@ -181,31 +181,6 @@ DWARFUnit::DWARFUnit(DWARFContext &DC, const DWARFSection &Section,
StringOffsetSection(SOS), AddrOffsetSection(AOS), isLittleEndian(LE),
IsDWO(IsDWO), UnitVector(UnitVector) {
clear();
- if (IsDWO) {
- // If we are reading a package file, we need to adjust the location list
- // data based on the index entries.
- StringRef Data = Header.getVersion() >= 5
- ? Context.getDWARFObj().getLoclistsDWOSection().Data
- : LocSection->Data;
- if (auto *IndexEntry = Header.getIndexEntry())
- if (const auto *C = IndexEntry->getContribution(
- Header.getVersion() >= 5 ? DW_SECT_LOCLISTS : DW_SECT_EXT_LOC))
- Data = Data.substr(C->Offset, C->Length);
-
- DWARFDataExtractor DWARFData(Data, isLittleEndian, getAddressByteSize());
- LocTable =
- std::make_unique<DWARFDebugLoclists>(DWARFData, Header.getVersion());
- } else if (Header.getVersion() >= 5) {
- LocTable = std::make_unique<DWARFDebugLoclists>(
- DWARFDataExtractor(Context.getDWARFObj(),
- Context.getDWARFObj().getLoclistsSection(),
- isLittleEndian, getAddressByteSize()),
- Header.getVersion());
- } else {
- LocTable = std::make_unique<DWARFDebugLoc>(
- DWARFDataExtractor(Context.getDWARFObj(), *LocSection, isLittleEndian,
- getAddressByteSize()));
- }
}
DWARFUnit::~DWARFUnit() = default;
@@ -492,8 +467,8 @@ Error DWARFUnit::tryExtractDIEsIfNeeded(bool CUDieOnly) {
// describe address ranges.
if (getVersion() >= 5) {
// In case of DWP, the base offset from the index has to be added.
- uint64_t ContributionBaseOffset = 0;
if (IsDWO) {
+ uint64_t ContributionBaseOffset = 0;
if (auto *IndexEntry = Header.getIndexEntry())
if (auto *Contrib = IndexEntry->getContribution(DW_SECT_RNGLISTS))
ContributionBaseOffset = Contrib->Offset;
@@ -506,42 +481,33 @@ Error DWARFUnit::tryExtractDIEsIfNeeded(bool CUDieOnly) {
toSectionOffset(UnitDie.find(DW_AT_rnglists_base),
DWARFListTableHeader::getHeaderSize(
Header.getFormat())));
+ }
- // In a split dwarf unit, there is no DW_AT_loclists_base attribute.
- // Setting LocSectionBase to point past the table header.
- if (IsDWO) {
- auto &DWOSection = Context.getDWARFObj().getLoclistsDWOSection();
- if (DWOSection.Data.empty())
- return Error::success();
- setLocSection(&DWOSection,
- DWARFListTableHeader::getHeaderSize(Header.getFormat()));
- } else if (auto X = UnitDie.find(DW_AT_loclists_base)) {
- setLocSection(&Context.getDWARFObj().getLoclistsSection(),
- toSectionOffset(X, 0));
- } else {
- return Error::success();
- }
+ if (IsDWO) {
+ // If we are reading a package file, we need to adjust the location list
+ // data based on the index entries.
+ StringRef Data = Header.getVersion() >= 5
+ ? Context.getDWARFObj().getLoclistsDWOSection().Data
+ : Context.getDWARFObj().getLocDWOSection().Data;
+ if (auto *IndexEntry = Header.getIndexEntry())
+ if (const auto *C = IndexEntry->getContribution(
+ Header.getVersion() >= 5 ? DW_SECT_LOCLISTS : DW_SECT_EXT_LOC))
+ Data = Data.substr(C->Offset, C->Length);
- if (LocSection) {
- if (IsDWO)
- LoclistTableHeader.emplace(".debug_loclists.dwo", "locations");
- else
- LoclistTableHeader.emplace(".debug_loclists", "locations");
-
- uint64_t HeaderSize = DWARFListTableHeader::getHeaderSize(Header.getFormat());
- uint64_t Offset = getLocSectionBase();
- const DWARFDataExtractor &Data = LocTable->getData();
- if (Offset < HeaderSize)
- return createStringError(errc::invalid_argument,
- "did not detect a valid"
- " list table with base = 0x%" PRIx64 "\n",
- Offset);
- Offset -= HeaderSize;
- if (Error E = LoclistTableHeader->extract(Data, &Offset))
- return createStringError(errc::invalid_argument,
- "parsing a loclist table: " +
- toString(std::move(E)));
- }
+ DWARFDataExtractor DWARFData(Data, isLittleEndian, getAddressByteSize());
+ LocTable =
+ std::make_unique<DWARFDebugLoclists>(DWARFData, Header.getVersion());
+ LocSectionBase = DWARFListTableHeader::getHeaderSize(Header.getFormat());
+ } else if (getVersion() >= 5) {
+ LocTable = std::make_unique<DWARFDebugLoclists>(
+ DWARFDataExtractor(Context.getDWARFObj(),
+ Context.getDWARFObj().getLoclistsSection(),
+ isLittleEndian, getAddressByteSize()),
+ getVersion());
+ } else {
+ LocTable = std::make_unique<DWARFDebugLoc>(DWARFDataExtractor(
+ Context.getDWARFObj(), Context.getDWARFObj().getLocSection(),
+ isLittleEndian, getAddressByteSize()));
}
// Don't fall back to DW_AT_GNU_ranges_base: it should be ignored for
@@ -981,3 +947,10 @@ Optional<uint64_t> DWARFUnit::getRnglistOffset(uint32_t Index) {
return *Off + RangeSectionBase;
return None;
}
+
+Optional<uint64_t> DWARFUnit::getLoclistOffset(uint32_t Index) {
+ if (Optional<uint64_t> Off = llvm::DWARFListTableHeader::getOffsetEntry(
+ LocTable->getData(), LocSectionBase, getFormat(), Index))
+ return *Off + LocSectionBase;
+ return None;
+}
diff --git a/llvm/test/tools/llvm-dwarfdump/X86/debug_loclists_unused_invalid.s b/llvm/test/tools/llvm-dwarfdump/X86/debug_loclists_unused_invalid.s
new file mode 100644
index 000000000000..5a8c9886829d
--- /dev/null
+++ b/llvm/test/tools/llvm-dwarfdump/X86/debug_loclists_unused_invalid.s
@@ -0,0 +1,230 @@
+# REQUIRES: x86-registered-target
+
+# RUN: rm -rf %t
+# RUN: mkdir %t
+# RUN: cd %t
+# RUN: llvm-mc %s -dwarf-version=5 -filetype obj -triple x86_64-pc-linux -o main.o
+# RUN: llvm-dwarfdump main.o 2>&1 | FileCheck %s
+
+# CHECK: .debug_info.dwo contents:
+# CHECK-NEXT: Compile Unit:
+# CHECK-EMPTY:
+# CHECK-NEXT: compile_unit
+
+ .text
+ .file "main.cpp"
+ .globl main # -- Begin function main
+ .p2align 4, 0x90
+ .type main, at function
+main: # @main
+.Lfunc_begin0:
+ .file 0 "/usr/local/google/home/blaikie/dev/scratch" "main.cpp" md5 0x277b2d67900f5d0f46c9638ad2528ff1
+ .loc 0 1 0 # main.cpp:1:0
+ .cfi_startproc
+# %bb.0: # %entry
+ pushq %rbp
+ .cfi_def_cfa_offset 16
+ .cfi_offset %rbp, -16
+ movq %rsp, %rbp
+ .cfi_def_cfa_register %rbp
+ xorl %eax, %eax
+.Ltmp0:
+ .loc 0 2 1 prologue_end # main.cpp:2:1
+ popq %rbp
+ .cfi_def_cfa %rsp, 8
+ retq
+.Ltmp1:
+.Lfunc_end0:
+ .size main, .Lfunc_end0-main
+ .cfi_endproc
+ # -- End function
+ .section .debug_abbrev,"", at 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,"", at 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 6318074710904753300
+ .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,"", at progbits
+ .long 12 # Length of String Offsets Set
+ .short 5
+ .short 0
+.Lstr_offsets_base0:
+ .section .debug_str,"MS", at progbits,1
+.Lskel_string0:
+ .asciz "" # string offset=0
+.Lskel_string1:
+ .asciz "main.o" # string offset=43
+ .section .debug_str_offsets,"", at progbits
+ .long .Lskel_string0
+ .long .Lskel_string1
+ .section .debug_str_offsets.dwo,"e", at progbits
+ .long 24 # Length of String Offsets Set
+ .short 5
+ .short 0
+ .section .debug_str.dwo,"eMS", at progbits,1
+.Linfo_string0:
+ .asciz "main" # string offset=0
+.Linfo_string1:
+ .asciz "int" # string offset=5
+.Linfo_string2:
+ .asciz "clang version 12.0.0 (git at github.com:llvm/llvm-project.git 9a33f027ac7d73e14ae287e78ab554142d1cbc8f)" # string offset=9
+.Linfo_string3:
+ .asciz "main.cpp" # string offset=110
+.Linfo_string4:
+ .asciz "main.s" # string offset=119
+ .section .debug_str_offsets.dwo,"e", at progbits
+ .long 0
+ .long 5
+ .long 9
+ .long 110
+ .long 119
+ .section .debug_info.dwo,"e", at 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 6318074710904753300
+ .byte 1 # Abbrev [1] 0x14:0x1a DW_TAG_compile_unit
+ .byte 2 # DW_AT_producer
+ .short 33 # 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 1 # 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
+.Ldebug_info_dwo_end0:
+ .section .debug_abbrev.dwo,"e", at 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,"", at 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,"", at 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,"", at 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 12.0.0 (git at github.com:llvm/llvm-project.git 9a33f027ac7d73e14ae287e78ab554142d1cbc8f)"
+ .section ".note.GNU-stack","", at progbits
+ .addrsig
+ .section .debug_line,"", at progbits
+.Lline_table_start0:
+ .section .debug_loclists.dwo,"e", at progbits
+ .byte 0
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