[llvm-objdump] Fix 'llvm-objdump -dr' for executables with relocations

Print relocations interleaved with disassembled instructions for
executables with relocatable sections, e.g. those built with "-Wl,-q".

Differential Revision: https://reviews.llvm.org/D109016

(cherry picked from commit 6300e4ac5806c9255c68c6fada37b2ce70efc524)
This commit is contained in:
Maksim Panchenko 2021-08-31 11:53:54 -07:00 committed by Tom Stellard
parent 09c230ecec
commit 64f4a52b52
2 changed files with 66 additions and 2 deletions

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@ -0,0 +1,59 @@
## Check that 'llvm-objdump -dr' correctly prints relocations in executables.
# RUN: yaml2obj --docnum=1 %s -o %t
# RUN: llvm-objdump -dr %t | FileCheck %s
# CHECK: 400000: 90 nop
# CHECK-NEXT: 400001: bf 10 00 40 00 movl $4194320, %edi
# CHECK-NEXT: 0000000000400002: R_X86_64_32 .rodata
# CHECK-NEXT: 400006: e8 fc fe ff ff callq 0x3fff07
# CHECK-NEXT: 0000000000400007: R_X86_64_PLT32 puts-0x4
# CHECK-NEXT: 40000b: 90 nop
--- !ELF
FileHeader:
Class: ELFCLASS64
Data: ELFDATA2LSB
Type: ET_EXEC
Machine: EM_X86_64
ProgramHeaders:
- Type: PT_LOAD
Flags: [ PF_X, PF_R ]
FirstSec: .text
LastSec: .rodata
VAddr: 0x400000
Sections:
- Name: .text
Type: SHT_PROGBITS
Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
Address: 0x400000
AddressAlign: 0x10
Content: 90BF10004000E8FCFEFFFF90
- Name: .rodata
Type: SHT_PROGBITS
Flags: [ SHF_ALLOC ]
AddressAlign: 0x8
Content: 00
- Name: .rela.text
Type: SHT_RELA
Flags: [ SHF_INFO_LINK ]
AddressAlign: 0x8
Info: .text
Relocations:
- Offset: 0x400002
Symbol: .rodata
Type: R_X86_64_32
Addend: 0
- Offset: 0x400007
Symbol: puts
Type: R_X86_64_PLT32
Addend: -4
Symbols:
- Name: .rodata
Type: STT_SECTION
Section: .rodata
Value: 0x400628
- Name: puts
Type: STT_FUNC
Binding: STB_GLOBAL
...

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@ -1286,6 +1286,10 @@ static void disassembleObject(const Target *TheTarget, const ObjectFile *Obj,
if (shouldAdjustVA(Section))
VMAAdjustment = AdjustVMA;
// In executable and shared objects, r_offset holds a virtual address.
// Subtract SectionAddr from the r_offset field of a relocation to get
// the section offset.
uint64_t RelAdjustment = Obj->isRelocatableObject() ? 0 : SectionAddr;
uint64_t Size;
uint64_t Index;
bool PrintedSection = false;
@ -1432,7 +1436,8 @@ static void disassembleObject(const Target *TheTarget, const ObjectFile *Obj,
// For --reloc: print zero blocks patched by relocations, so that
// relocations can be shown in the dump.
if (RelCur != RelEnd)
MaxOffset = RelCur->getOffset() - Index;
MaxOffset = std::min(RelCur->getOffset() - RelAdjustment - Index,
MaxOffset);
if (size_t N =
countSkippableZeroBytes(Bytes.slice(Index, MaxOffset))) {
@ -1581,7 +1586,7 @@ static void disassembleObject(const Target *TheTarget, const ObjectFile *Obj,
if (Obj->getArch() != Triple::hexagon) {
// Print relocation for instruction and data.
while (RelCur != RelEnd) {
uint64_t Offset = RelCur->getOffset();
uint64_t Offset = RelCur->getOffset() - RelAdjustment;
// If this relocation is hidden, skip it.
if (getHidden(*RelCur) || SectionAddr + Offset < StartAddress) {
++RelCur;