[Lldb-commits] [lldb] c314f5e - ObjectFileELF: Test whether reloc_header is non-null instead of asserting.
Peter Collingbourne via lldb-commits
lldb-commits at lists.llvm.org
Thu Feb 11 15:05:43 PST 2021
Author: Peter Collingbourne
Date: 2021-02-11T15:05:18-08:00
New Revision: c314f5ede8249ef20fff1de45c2c31156b1950d4
URL: https://github.com/llvm/llvm-project/commit/c314f5ede8249ef20fff1de45c2c31156b1950d4
DIFF: https://github.com/llvm/llvm-project/commit/c314f5ede8249ef20fff1de45c2c31156b1950d4.diff
LOG: ObjectFileELF: Test whether reloc_header is non-null instead of asserting.
It is possible for the GetSectionHeaderByIndex lookup to fail because
the previous FindSectionContainingFileAddress lookup found a segment
instead of a section. This is possible if the binary does not have
a PLT (which means that lld will in some circumstances set DT_JMPREL
to 0, which is typically an address that is part of the ELF headers
and not in a section) and may also be possible if the section headers
have been stripped. To handle this possibility, replace the assert
with an if.
Differential Revision: https://reviews.llvm.org/D93438
Added:
lldb/test/Shell/ObjectFile/ELF/null-jmprel.yaml
Modified:
lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
Removed:
################################################################################
diff --git a/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp b/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
index cad9ce218b10..df0586367832 100644
--- a/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
+++ b/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
@@ -2770,14 +2770,14 @@ Symtab *ObjectFileELF::GetSymtab() {
user_id_t reloc_id = reloc_section->GetID();
const ELFSectionHeaderInfo *reloc_header =
GetSectionHeaderByIndex(reloc_id);
- assert(reloc_header);
+ if (reloc_header) {
+ if (m_symtab_up == nullptr)
+ m_symtab_up =
+ std::make_unique<Symtab>(reloc_section->GetObjectFile());
- if (m_symtab_up == nullptr)
- m_symtab_up =
- std::make_unique<Symtab>(reloc_section->GetObjectFile());
-
- ParseTrampolineSymbols(m_symtab_up.get(), symbol_id, reloc_header,
- reloc_id);
+ ParseTrampolineSymbols(m_symtab_up.get(), symbol_id, reloc_header,
+ reloc_id);
+ }
}
}
diff --git a/lldb/test/Shell/ObjectFile/ELF/null-jmprel.yaml b/lldb/test/Shell/ObjectFile/ELF/null-jmprel.yaml
new file mode 100644
index 000000000000..ae151ba8cdc1
--- /dev/null
+++ b/lldb/test/Shell/ObjectFile/ELF/null-jmprel.yaml
@@ -0,0 +1,148 @@
+# RUN: yaml2obj %s -o %t
+# RUN: lldb-test symbols %t | FileCheck %s
+
+# CHECK: _DYNAMIC
+# CHECK: _start
+
+--- !ELF
+FileHeader:
+ Class: ELFCLASS64
+ Data: ELFDATA2LSB
+ Type: ET_DYN
+ Machine: EM_X86_64
+ Entry: 0x1000
+ProgramHeaders:
+ - Type: PT_PHDR
+ Flags: [ PF_R ]
+ VAddr: 0x40
+ Align: 0x8
+ - Type: PT_LOAD
+ Flags: [ PF_R ]
+ FirstSec: .dynsym
+ LastSec: .dynstr
+ Align: 0x1000
+ - Type: PT_LOAD
+ Flags: [ PF_X, PF_R ]
+ FirstSec: .text
+ LastSec: .text
+ VAddr: 0x1000
+ Align: 0x1000
+ - Type: PT_LOAD
+ Flags: [ PF_W, PF_R ]
+ FirstSec: .data
+ LastSec: .bss
+ VAddr: 0x2000
+ Align: 0x1000
+ - Type: PT_DYNAMIC
+ Flags: [ PF_W, PF_R ]
+ FirstSec: .data
+ LastSec: .dynamic
+ VAddr: 0x2000
+ Align: 0x8
+ - Type: PT_GNU_RELRO
+ Flags: [ PF_R ]
+ FirstSec: .data
+ LastSec: .bss
+ VAddr: 0x2000
+ - Type: PT_GNU_STACK
+ Flags: [ PF_W, PF_R ]
+ Align: 0x0
+Sections:
+ - Name: .dynsym
+ Type: SHT_DYNSYM
+ Flags: [ SHF_ALLOC ]
+ Address: 0x1C8
+ Link: .dynstr
+ AddressAlign: 0x8
+ EntSize: 0x18
+ - Name: .gnu.hash
+ Type: SHT_GNU_HASH
+ Flags: [ SHF_ALLOC ]
+ Address: 0x1F8
+ Link: .dynsym
+ AddressAlign: 0x8
+ Header:
+ SymNdx: 0x1
+ Shift2: 0x6
+ BloomFilter: [ 0x4000000000100 ]
+ HashBuckets: [ 0x1 ]
+ HashValues: [ 0xEDDB6233 ]
+ - Name: .hash
+ Type: SHT_HASH
+ Flags: [ SHF_ALLOC ]
+ Address: 0x218
+ Link: .dynsym
+ AddressAlign: 0x4
+ Bucket: [ 1, 0 ]
+ Chain: [ 0, 0 ]
+ - Name: .dynstr
+ Type: SHT_STRTAB
+ Flags: [ SHF_ALLOC ]
+ Address: 0x230
+ AddressAlign: 0x1
+ - Name: .text
+ Type: SHT_PROGBITS
+ Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
+ Address: 0x1000
+ AddressAlign: 0x1
+ Offset: 0x1000
+ Content: C3
+ - Name: .data
+ Type: SHT_PROGBITS
+ Flags: [ SHF_WRITE, SHF_ALLOC ]
+ Address: 0x2000
+ AddressAlign: 0x1
+ Offset: 0x2000
+ - Name: .dynamic
+ Type: SHT_DYNAMIC
+ Flags: [ SHF_WRITE, SHF_ALLOC ]
+ Address: 0x2000
+ Link: .dynstr
+ AddressAlign: 0x8
+ Entries:
+ - Tag: DT_SYMTAB
+ Value: 0x1C8
+ - Tag: DT_SYMENT
+ Value: 0x18
+ - Tag: DT_STRTAB
+ Value: 0x230
+ - Tag: DT_STRSZ
+ Value: 0x8
+ - Tag: DT_GNU_HASH
+ Value: 0x1F8
+ - Tag: DT_HASH
+ Value: 0x218
+ - Tag: DT_JMPREL
+ Value: 0x0
+ - Tag: DT_PLTRELSZ
+ Value: 0x0
+ - Tag: DT_NULL
+ Value: 0x0
+ - Name: .bss
+ Type: SHT_NOBITS
+ Flags: [ SHF_WRITE, SHF_ALLOC ]
+ Address: 0x3000
+ AddressAlign: 0x1
+ - Name: .comment
+ Type: SHT_PROGBITS
+ Flags: [ SHF_MERGE, SHF_STRINGS ]
+ AddressAlign: 0x1
+ EntSize: 0x1
+ Content: 4C696E6B65723A204C4C4420372E302E3000
+Symbols:
+ - Name: _DYNAMIC
+ Section: .dynamic
+ Value: 0x2000
+ Other: [ STV_HIDDEN ]
+ - Name: _start
+ Type: STT_FUNC
+ Section: .text
+ Binding: STB_GLOBAL
+ Value: 0x1000
+DynamicSymbols:
+ - Name: _start
+ Type: STT_FUNC
+ Section: .text
+ Binding: STB_GLOBAL
+ Value: 0x1000
+...
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