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[llvm-readelf] - Do not omit a zero symbol value when printing relocations.

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Previously we only printed a symbol value when it has a non-empty name
or non-zero value.

This patch changes the behavior. Now we only omit a symbols value when
a relocation does not reference a symbol (i.e. symbol index == 0).

Seems it is what GNU readelf does, looking on its output.

Differential revision: https://reviews.llvm.org/D81842
This commit is contained in:
Georgii Rymar 2020-06-15 15:18:29 +03:00
parent 245b299edc
commit cdd7f24c3a
2 changed files with 31 additions and 12 deletions
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39
llvm/test/tools/llvm-readobj/ELF/reloc-zero-name-or-value.test
View file

@ -1,30 +1,33 @@
# Show that the value field is omitted if a symbol has no name or value, but is
# printed if one is present. Test for both static and dynamic relocation
# printing.
## Show that the value field is omitted when a relocation does not reference a symbol.
## In other cases, particularly when a symbol has a zero value or when it has an empty
## name, we print it. Test for both static and dynamic relocation printing.
# RUN: yaml2obj %s -o %t
# RUN: llvm-readelf --relocations --dyn-relocations %t | FileCheck %s
# CHECK: Relocation section '.rela.text' at offset {{.*}} contains 4 entries:
# CHECK: Relocation section '.rela.text' at offset {{.*}} contains 5 entries:
# CHECK-NEXT: Offset Info Type Symbol's Value Symbol's Name + Addend
# CHECK-NEXT: 0000000000000000 0000000000000000 R_X86_64_NONE 1
# CHECK-NEXT: 0000000000000000 0000000100000000 R_X86_64_NONE 0000000000000000 sym + 1
# CHECK-NEXT: 0000000000000000 0000000200000000 R_X86_64_NONE 0000000000000123 456
# CHECK-NEXT: 0000000000000000 0000000300000000 R_X86_64_NONE 678
# CHECK-NEXT: 0000000000000000 0000000300000000 R_X86_64_NONE 0000000000000000 678
# CHECK-NEXT: 0000000000000000 0000000400000000 R_X86_64_NONE 0000000000000000 2
# CHECK: Relocation section '.rela.dyn' at offset {{.*}} contains 4 entries:
# CHECK: Relocation section '.rela.dyn' at offset {{.*}} contains 5 entries:
# CHECK-NEXT: Offset Info Type Symbol's Value Symbol's Name + Addend
# CHECK-NEXT: 0000000000000000 0000000000000000 R_X86_64_NONE 1
# CHECK-NEXT: 0000000000000000 0000000100000000 R_X86_64_NONE 0000000000000000 sym + 1
# CHECK-NEXT: 0000000000000000 0000000200000000 R_X86_64_NONE 0000000000000123 456
# CHECK-NEXT: 0000000000000000 0000000300000000 R_X86_64_NONE 678
# CHECK-NEXT: 0000000000000000 0000000300000000 R_X86_64_NONE 0000000000000000 678
# CHECK-NEXT: 0000000000000000 0000000400000000 R_X86_64_NONE 0000000000000000 2
# CHECK: 'RELA' relocation section at offset {{.*}} contains 96 bytes:
# CHECK: 'RELA' relocation section at offset {{.*}} contains 120 bytes:
# CHECK-NEXT: Offset Info Type Symbol's Value Symbol's Name + Addend
# CHECK-NEXT: 0000000000000000 0000000000000000 R_X86_64_NONE 1
# CHECK-NEXT: 0000000000000000 0000000100000000 R_X86_64_NONE 0000000000000000 sym + 1
# CHECK-NEXT: 0000000000000000 0000000200000000 R_X86_64_NONE 0000000000000123 456
# CHECK-NEXT: 0000000000000000 0000000300000000 R_X86_64_NONE 678
# CHECK-NEXT: 0000000000000000 0000000300000000 R_X86_64_NONE 0000000000000000 678
# CHECK-NEXT: 0000000000000000 0000000400000000 R_X86_64_NONE 0000000000000000 2
--- !ELF
FileHeader:
@ -56,6 +59,11 @@ Sections:
Addend: 0x678
Type: R_X86_64_NONE
Symbol: 3
## References a symbol with a zero value and an empty name.
- Offset: 0
Type: R_X86_64_NONE
Addend: 2
Symbol: 4
- Name: .dynamic
Type: SHT_DYNAMIC
Flags: [SHF_ALLOC]
@ -65,7 +73,7 @@ Sections:
- Tag: DT_RELA
Value: 0x1100
- Tag: DT_RELASZ
Value: 96
Value: 120
- Tag: DT_RELAENT
Value: 24
- Tag: DT_NULL
@ -92,6 +100,11 @@ Sections:
Addend: 0x678
Type: R_X86_64_NONE
Symbol: 3
## References a symbol with a zero value and an empty name.
- Offset: 0
Type: R_X86_64_NONE
Addend: 2
Symbol: 4
Symbols:
- Name: sym
Value: 0
@ -102,6 +115,9 @@ Symbols:
Binding: STB_GLOBAL
- Type: STT_SECTION
Index: 0
- Value: 0x0
Section: .text
Binding: STB_GLOBAL
DynamicSymbols:
- Name: sym
Value: 0
@ -112,6 +128,9 @@ DynamicSymbols:
Binding: STB_GLOBAL
- Type: STT_SECTION
Index: 0
- Value: 0x0
Section: .text
Binding: STB_GLOBAL
ProgramHeaders:
- Type: PT_LOAD
VAddr: 0x1000

4
llvm/tools/llvm-readobj/ELFDumper.cpp
View file

@ -3519,7 +3519,7 @@ void GNUStyle<ELFT>::printRelocation(const ELFO *Obj, const Elf_Sym *Sym,
Obj->getRelocationTypeName(R.getType(Obj->isMips64EL()), RelocName);
Fields[2].Str = RelocName.c_str();
if (Sym && (!SymbolName.empty() || Sym->getValue() != 0))
if (Sym)
Fields[3].Str = to_string(format_hex_no_prefix(Sym->getValue(), Width));
Fields[4].Str = std::string(SymbolName);
@ -4312,7 +4312,7 @@ RelSymbol<ELFT> getSymbolForReloc(const ELFFile<ELFT> *Obj, StringRef FileName,
if (!ErrOrName)
return WarnAndReturn(Sym, toString(ErrOrName.takeError()));
return {Sym, maybeDemangle(*ErrOrName)};
return {Sym == FirstSym ? nullptr : Sym, maybeDemangle(*ErrOrName)};
}
} // namespace