[llvm-objdump] Fix -R display and support ET_EXEC

[MaskRay]

Summary

• Add a newline before DYNAMIC RELOCATION RECORDS (see D101796)
• Add the missing OFFSET TYPE VALUE line
• Align columns

Note: llvm-readobj/ELFDumper.cpp loadDynamicTable has sophisticated PT_DYNAMIC
code which is unavailable in llvm-objdump.

[Higuoxing]

LGTM.

[jhenderson]

LGTM, with one other suggestion.

llvm/test/tools/llvm-objdump/ELF/dynamic-relocs.test

20–21

It might be interesting to perform one of these runs (or an additional run) with an arbitrary ELF type e.g. 0x1234, to better show that the type doesn't matter at all.

[MaskRay]

use an arbitrary type

lld/test/ELF/got32-i386-pie-rw.s

 
 # CHECK-LABEL: SYMBOL TABLE:
 # REL:  00001180 l       .text  00000000 foo
 # REL:  00002180 g       .foobar  00000000 _start
 # RELA: 00001188 l       .text  00000000 foo
 # RELA: 00002188 g       .foobar  00000000 _start
 
 # CHECK-LABEL: DYNAMIC RELOCATION RECORDS
+# CHECK-NEXT:  OFFSET TYPE           VALUE
 # REL-NEXT:  00002182 R_386_RELATIVE *ABS*{{$}}
 # REL-NEXT:  000031f0 R_386_RELATIVE *ABS*{{$}}
 # RELA-NEXT: 0000218a R_386_RELATIVE *ABS*+0x31f8{{$}}
 # RELA-NEXT: 000031f8 R_386_RELATIVE *ABS*+0x1188{{$}}
 # CHECK-NEXT: Contents of section .foobar:
 # REL-NEXT:   2180 8b1df031 0000
 ##                     ^--- VA of GOT entry (0x31f0)
 # RELA-NEXT:  2188 8b1d0000 0000

llvm/test/tools/llvm-objdump/ELF/dynamic-relocs.test

+## Show that llvm-objdump can dump dynamic relocations.
+## Specifically, we are checking that the tags DT_RELA, DT_REL and DT_JMPREL
+## properly identify relocation tables.
+
+# RUN: yaml2obj --docnum=1 %s -o %t.empty
+# RUN: not llvm-objdump -R %t.empty 2>&1 | FileCheck %s --check-prefix=NO-DYNAMIC
+
+# NO-DYNAMIC: error: '{{.*}}': not a dynamic object
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_DYN
+
+# RUN: yaml2obj --docnum=2 -DTYPE=ET_EXEC %s -o %t1
+# RUN: llvm-objdump --dynamic-reloc %t1 | FileCheck %s --strict-whitespace --match-full-lines
+
+## e_type doesn't matter at all.
+# RUN: yaml2obj --docnum=2 -DTYPE=0x1234 %s -o %t2
+# RUN: llvm-objdump -R %t2 | FileCheck %s --strict-whitespace --match-full-lines
+
+#      CHECK:{{.*}}file format elf64-x86-64
+#CHECK-EMPTY:
+# CHECK-NEXT:DYNAMIC RELOCATION RECORDS
+# CHECK-NEXT:OFFSET           TYPE                     VALUE
+# CHECK-NEXT:0000000000000000 R_X86_64_RELATIVE        *ABS*
+# CHECK-NEXT:0000000000000000 R_X86_64_JUMP_SLOT       bar
+# CHECK-NEXT:0000000000000008 R_X86_64_NONE            foo
+#CHECK-EMPTY:
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    [[TYPE]]
+  Machine: EM_X86_64
+Sections:
+  - Name:         .foo
+    Type:         SHT_PROGBITS
+    Size:         16
+    Flags:        [SHF_ALLOC]
+    Address:      0x100000
+    AddressAlign: 0x100
+  - Name:         .got.plt
+    Type:         SHT_PROGBITS
+    Flags:        [SHF_WRITE, SHF_ALLOC]
+    Address:      0x100100
+    AddressAlign: 0x1000
+  - Name:         .rela.dyn
+    Type:         SHT_RELA
+    Address:      0x100200
+    AddressAlign: 0x100
+    Info:         .foo
+    Link:         .dynsym
+    Flags:        [SHF_ALLOC]
+    Relocations:
+      - Offset: 0
+        Type:   R_X86_64_RELATIVE
+        Addend: 0
+  - Name:         .rela.plt
+    Type:         SHT_RELA
+    Address:      0x100300
+    AddressAlign: 0x100
+    Info:         .got.plt
+    Link:         .dynsym
+    Flags:        [SHF_ALLOC]
+    Relocations:
+      - Offset: 0
+        Symbol: bar
+        Type:   R_X86_64_JUMP_SLOT
+  - Name:         .rel.dyn
+    Type:         SHT_REL
+    Address:      0x100400
+    AddressAlign: 0x100
+    Info:         .foo
+    Link:         .dynsym
+    Flags:        [SHF_ALLOC]
+    Relocations:
+      - Offset: 8
+        Symbol: foo
+        Type:   R_X86_64_NONE
+  - Name:         .dynamic
+    Type:         SHT_DYNAMIC
+    Address:      0x100500
+    AddressAlign: 0x100
+    Link:         .dynstr
+    Flags:        [SHF_ALLOC]
+    Entries:
+      - Tag: DT_RELA
+        Value: 0x100200
+      - Tag: DT_RELASZ
+        Value: 24
+      - Tag: DT_RELAENT
+        Value: 24
+      - Tag: DT_JMPREL
+        Value: 0x100300
+      - Tag: DT_PLTREL
+        Value: 7
+      - Tag: DT_PLTRELSZ
+        Value: 24
+      - Tag: DT_REL
+        Value: 0x100400
+      - Tag: DT_RELSZ
+        Value: 16
+      - Tag: DT_RELENT
+        Value: 16
+      - Tag: DT_NULL
+        Value: 0
+ProgramHeaders:
+  - Type:     PT_LOAD
+    VAddr:    0x100000
+    Align:    0x100
+    FirstSec: .foo
+    LastSec:  .dynamic
+  - Type:     PT_DYNAMIC
+    VAddr:    0x100500
+    Align:    0x100
+    FirstSec: .dynamic
+    LastSec:  .dynamic
+DynamicSymbols:
+  - Name:    foo
+    Section: .foo
+    Binding: STB_GLOBAL
+  - Name:    bar
+    Type:    STT_FUNC
+    Binding: STB_GLOBAL
+
+## Test a 32-bit object.
+# RUN: yaml2obj --docnum=3 %s -o %t.i386
+# RUN: llvm-objdump -R %t.i386 | FileCheck %s --check-prefix=I386 --strict-whitespace --match-full-lines
+
+#      I386:{{.*}}file format elf32-i386
+#I386-EMPTY:
+# I386-NEXT:DYNAMIC RELOCATION RECORDS
+# I386-NEXT:OFFSET   TYPE                     VALUE
+# I386-NEXT:00000030 R_386_RELATIVE           *ABS*
+# I386-NEXT:00000010 R_386_NONE               foo
+#I386-EMPTY:
+
+--- !ELF
+FileHeader:
+  Class:           ELFCLASS32
+  Data:            ELFDATA2LSB
+  Type:            ET_DYN
+  Machine:         EM_386
+ProgramHeaders:
+  - Type:     PT_LOAD
+    FirstSec: .rel.dyn
+    LastSec:  .data
+  - Type:     PT_DYNAMIC
+    VAddr:    0x10
+    FirstSec: .dynamic
+    LastSec:  .dynamic
+Sections:
+  - Name:            .rel.dyn
+    Type:            SHT_REL
+    Link:            .dynsym
+    Flags:           [ SHF_ALLOC ]
+    AddressAlign:    0x4
+    Relocations:
+      - Offset:          0x30
+        Type:            R_386_RELATIVE
+      - Offset:          0x10
+        Symbol:          foo
+        Type:            R_386_NONE
+  - Name:            .dynamic
+    Type:            SHT_DYNAMIC
+    Flags:           [ SHF_ALLOC ]
+    Link:            .dynstr
+    AddressAlign:    0x4
+    Entries:
+      - Tag:             DT_REL
+        Value:           0x0
+      - Tag:             DT_RELSZ
+        Value:           0x10
+      - Tag:             DT_RELENT
+        Value:           0x8
+      - Tag:             DT_RELCOUNT
+        Value:           0x1
+      - Tag:             DT_NULL
+        Value:           0x0
+  - Name:            .data
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_WRITE, SHF_ALLOC ]
+    AddressAlign:    0x4
+    Content:         '80110000'
+DynamicSymbols:
+  - Name:    foo
+    Section: .data

llvm/test/tools/llvm-objdump/X86/elf-dynamic-relocs-rel.test

-## Show that llvm-objdump can dump dynamic relocations for Elf_Rel relocations
-## where the relocation references a symbol and where it does not.
-
-# RUN: yaml2obj %s -o %t
-# RUN: llvm-objdump --dynamic-reloc %t | FileCheck %s
-# RUN: llvm-objdump -R %t | FileCheck %s
-
-# CHECK:      DYNAMIC RELOCATION RECORDS
-# CHECK-NEXT: 00000030 R_386_RELATIVE *ABS*
-# CHECK-NEXT: 00000010 R_386_NONE foo
-# CHECK-EMPTY:
-
---- !ELF
-FileHeader:
-  Class:           ELFCLASS32
-  Data:            ELFDATA2LSB
-  Type:            ET_DYN
-  Machine:         EM_386
-ProgramHeaders:
-  - Type:     PT_LOAD
-    FirstSec: .rel.dyn
-    LastSec:  .data
-  - Type:     PT_DYNAMIC
-    VAddr:    0x10
-    FirstSec: .dynamic
-    LastSec:  .dynamic
-Sections:
-  - Name:            .rel.dyn
-    Type:            SHT_REL
-    Link:            .dynsym
-    Flags:           [ SHF_ALLOC ]
-    AddressAlign:    0x4
-    Relocations:
-      - Offset:          0x30
-        Type:            R_386_RELATIVE
-      - Offset:          0x10
-        Symbol:          foo
-        Type:            R_386_NONE
-  - Name:            .dynamic
-    Type:            SHT_DYNAMIC
-    Flags:           [ SHF_ALLOC ]
-    Link:            .dynstr
-    AddressAlign:    0x4
-    Entries:
-      - Tag:             DT_REL
-        Value:           0x0
-      - Tag:             DT_RELSZ
-        Value:           0x10
-      - Tag:             DT_RELENT
-        Value:           0x8
-      - Tag:             DT_RELCOUNT
-        Value:           0x1
-      - Tag:             DT_NULL
-        Value:           0x0
-  - Name:            .data
-    Type:            SHT_PROGBITS
-    Flags:           [ SHF_WRITE, SHF_ALLOC ]
-    AddressAlign:    0x4
-    Content:         '80110000'
-DynamicSymbols:
-  - Name:    foo
-    Section: .data

llvm/test/tools/llvm-objdump/X86/elf-dynamic-relocs.test

-## Show that llvm-objdump can dump dynamic relocations.
-## Specifically, we are checking that the tags DT_RELA, DT_REL and DT_JMPREL
-## properly identify relocation tables.
-
-# RUN: yaml2obj %s -o %t
-# RUN: llvm-objdump --dynamic-reloc %t | FileCheck %s
-# RUN: llvm-objdump -R %t | FileCheck %s
-
-# CHECK:      DYNAMIC RELOCATION RECORDS
-# CHECK-NEXT: 0000000000000000 R_X86_64_RELATIVE *ABS*
-# CHECK-NEXT: 0000000000000000 R_X86_64_JUMP_SLOT bar
-# CHECK-NEXT: 0000000000000008 R_X86_64_NONE foo
-# CHECK-EMPTY:
-
---- !ELF
-FileHeader:
-  Class:   ELFCLASS64
-  Data:    ELFDATA2LSB
-  Type:    ET_DYN
-  Machine: EM_X86_64
-Sections:
-  - Name:         .foo
-    Type:         SHT_PROGBITS
-    Size:         16
-    Flags:        [SHF_ALLOC]
-    Address:      0x100000
-    AddressAlign: 0x100
-  - Name:         .got.plt
-    Type:         SHT_PROGBITS
-    Flags:        [SHF_WRITE, SHF_ALLOC]
-    Address:      0x100100
-    AddressAlign: 0x1000
-  - Name:         .rela.dyn
-    Type:         SHT_RELA
-    Address:      0x100200
-    AddressAlign: 0x100
-    Info:         .foo
-    Link:         .dynsym
-    Flags:        [SHF_ALLOC]
-    Relocations:
-      - Offset: 0
-        Type:   R_X86_64_RELATIVE
-        Addend: 0
-  - Name:         .rela.plt
-    Type:         SHT_RELA
-    Address:      0x100300
-    AddressAlign: 0x100
-    Info:         .got.plt
-    Link:         .dynsym
-    Flags:        [SHF_ALLOC]
-    Relocations:
-      - Offset: 0
-        Symbol: bar
-        Type:   R_X86_64_JUMP_SLOT
-  - Name:         .rel.dyn
-    Type:         SHT_REL
-    Address:      0x100400
-    AddressAlign: 0x100
-    Info:         .foo
-    Link:         .dynsym
-    Flags:        [SHF_ALLOC]
-    Relocations:
-      - Offset: 8
-        Symbol: foo
-        Type:   R_X86_64_NONE
-  - Name:         .dynamic
-    Type:         SHT_DYNAMIC
-    Address:      0x100500
-    AddressAlign: 0x100
-    Link:         .dynstr
-    Flags:        [SHF_ALLOC]
-    Entries:
-      - Tag: DT_RELA
-        Value: 0x100200
-      - Tag: DT_RELASZ
-        Value: 24
-      - Tag: DT_RELAENT
-        Value: 24
-      - Tag: DT_JMPREL
-        Value: 0x100300
-      - Tag: DT_PLTREL
-        Value: 7
-      - Tag: DT_PLTRELSZ
-        Value: 24
-      - Tag: DT_REL
-        Value: 0x100400
-      - Tag: DT_RELSZ
-        Value: 16
-      - Tag: DT_RELENT
-        Value: 16
-      - Tag: DT_NULL
-        Value: 0
-ProgramHeaders:
-  - Type:     PT_LOAD
-    VAddr:    0x100000
-    Align:    0x100
-    FirstSec: .foo
-    LastSec:  .dynamic
-  - Type:     PT_DYNAMIC
-    VAddr:    0x100500
-    Align:    0x100
-    FirstSec: .dynamic
-    LastSec:  .dynamic
-DynamicSymbols:
-  - Name:    foo
-    Section: .foo
-    Binding: STB_GLOBAL
-  - Name:    bar
-    Type:    STT_FUNC
-    Binding: STB_GLOBAL

llvm/tools/llvm-objdump/llvm-objdump.cpp

 }
 
 void objdump::printDynamicRelocations(const ObjectFile *Obj) {
   // For the moment, this option is for ELF only
   if (!Obj->isELF())
     return;
 
   const auto *Elf = dyn_cast<ELFObjectFileBase>(Obj);
-  if (!Elf || Elf->getEType() != ELF::ET_DYN) {
+  if (!Elf || !any_of(Elf->sections(), [](const ELFSectionRef Sec) {
+        return Sec.getType() == ELF::SHT_DYNAMIC;
+      })) {
     reportError(Obj->getFileName(), "not a dynamic object");
     return;
   }
 
   std::vector<SectionRef> DynRelSec = Obj->dynamic_relocation_sections();
   if (DynRelSec.empty())
     return;
 
-  outs() << "DYNAMIC RELOCATION RECORDS\n";
+  outs() << "\nDYNAMIC RELOCATION RECORDS\n";
+  const uint32_t OffsetPadding = (Obj->getBytesInAddress() > 4 ? 16 : 8);
+  const uint32_t TypePadding = 24;
+  outs() << left_justify("OFFSET", OffsetPadding) << ' '
+         << left_justify("TYPE", TypePadding) << " VALUE\n";
+
   StringRef Fmt = Obj->getBytesInAddress() > 4 ? "%016" PRIx64 : "%08" PRIx64;
   for (const SectionRef &Section : DynRelSec)
     for (const RelocationRef &Reloc : Section.relocations()) {
       uint64_t Address = Reloc.getOffset();
       SmallString<32> RelocName;
       SmallString<32> ValueStr;
       Reloc.getTypeName(RelocName);
       if (Error E = getRelocationValueString(Reloc, ValueStr))
         reportError(std::move(E), Obj->getFileName());
-      outs() << format(Fmt.data(), Address) << " " << RelocName << " "
-             << ValueStr << "\n";
+      outs() << format(Fmt.data(), Address) << ' '
+             << left_justify(RelocName, TypePadding) << ' ' << ValueStr << '\n';
     }
 }
 
 // Returns true if we need to show LMA column when dumping section headers. We
 // show it only when the platform is ELF and either we have at least one section
 // whose VMA and LMA are different and/or when --show-lma flag is used.
 static bool shouldDisplayLMA(const ObjectFile *Obj) {
   if (!Obj->isELF())