[llvm-readobj] Solve the misalignment problem caused by RISCV_ATTRIBUTES

[achieveartificialintelligence]

Summary

RISCV_ATTRIBUTES causes the number of columns in Type to be insufficient

before

There are 12 section headers, starting at offset 0x4e0:

Section Headers:
  [Nr] Name              Type            Address          Off    Size   ES Flg Lk Inf Al
  [ 0]                   NULL            0000000000000000 000000 000000 00      0   0  0
  [ 1] .strtab           STRTAB          0000000000000000 0003fc 0000dd 00      0   0  1
  [ 2] .text             PROGBITS        0000000000000000 000040 000070 00  AX  0   0  4
  [ 3] .rela.text        RELA            0000000000000000 000260 000198 18   I 11   2  8
  [ 4] .sdata            PROGBITS        0000000000000000 0000b0 000008 00  WA  0   0  4
  [ 5] .rodata.str1.1    PROGBITS        0000000000000000 0000b8 000004 01 AMS  0   0  1
  [ 6] .sbss             NOBITS          0000000000000000 0000bc 000008 00  WA  0   0  4
  [ 7] .comment          PROGBITS        0000000000000000 0000bc 00006a 01  MS  0   0  1
  [ 8] .note.GNU-stack   PROGBITS        0000000000000000 000126 000000 00      0   0  1
  [ 9] .riscv.attributes RISCV_ATTRIBUTES 0000000000000000 000126 000047 00      0   0  1
  [10] .llvm_addrsig     LLVM_ADDRSIG    0000000000000000 0003f8 000004 00   E 11   0  1
  [11] .symtab           SYMTAB          0000000000000000 000170 0000f0 18      1   5  8

after

There are 12 section headers, starting at offset 0x4e0:

Section Headers:
  [Nr] Name              Type             Address          Off    Size   ES Flg Lk Inf Al
  [ 0]                   NULL             0000000000000000 000000 000000 00      0   0  0
  [ 1] .strtab           STRTAB           0000000000000000 0003fc 0000dd 00      0   0  1
  [ 2] .text             PROGBITS         0000000000000000 000040 000070 00  AX  0   0  4
  [ 3] .rela.text        RELA             0000000000000000 000260 000198 18   I 11   2  8
  [ 4] .sdata            PROGBITS         0000000000000000 0000b0 000008 00  WA  0   0  4
  [ 5] .rodata.str1.1    PROGBITS         0000000000000000 0000b8 000004 01 AMS  0   0  1
  [ 6] .sbss             NOBITS           0000000000000000 0000bc 000008 00  WA  0   0  4
  [ 7] .comment          PROGBITS         0000000000000000 0000bc 00006a 01  MS  0   0  1
  [ 8] .note.GNU-stack   PROGBITS         0000000000000000 000126 000000 00      0   0  1
  [ 9] .riscv.attributes RISCV_ATTRIBUTES 0000000000000000 000126 000047 00      0   0  1
  [10] .llvm_addrsig     LLVM_ADDRSIG     0000000000000000 0003f8 000004 00   E 11   0  1
  [11] .symtab           SYMTAB           0000000000000000 000170 0000f0 18      1   5  8

[achieveartificialintelligence]

update tests

[jrtc27]

llvm-readelf currently almost exactly matches the output of GNU readelf -W, and field widths for -S is one of the ways they currently match. I'm unconvinced this is worthwhile; .note.gnu.build-id already spills over into the Type column for any architecture, so this is not a new problem, and it's not really a problem either.

[achieveartificialintelligence]

In D116360#3212564, @jrtc27 wrote:

llvm-readelf currently almost exactly matches the output of GNU readelf -W, and field widths for -S is one of the ways they currently match. I'm unconvinced this is worthwhile; .note.gnu.build-id already spills over into the Type column for any architecture, so this is not a new problem, and it's not really a problem either.

Thanks, I'll close this.

llvm/test/tools/llvm-readobj/ELF/gnu-sections.test

 ## In this test case we check how we print section and flag descriptions for different targets.
 
 ## EM_NONE is a target that does not have any processor and OS specific flags,
 ## we use it to show how the default flag key is printed.
 
 # RUN: yaml2obj -DBITS=32 %s -o %t-default.o
 # RUN: llvm-readelf -S %t-default.o | FileCheck %s --check-prefix=ELF32 --strict-whitespace --match-full-lines
 
 #       ELF32:There are 9 section headers, starting at offset 0x9c:
 # ELF32-EMPTY:
 # ELF32-NEXT:Section Headers:
-# ELF32-NEXT:  [Nr] Name              Type            Address  Off    Size   ES Flg Lk Inf Al
-# ELF32-NEXT:  [ 0]                   NULL            00000000 000000 000000 00      0   0  0
-# ELF32-NEXT:  [ 1] .text             PROGBITS        00000000 000034 000001 00  AX  0   0  4
-# ELF32-NEXT:  [ 2] .rel.text         REL             00000000 000038 000000 08      6   1  4
-# ELF32-NEXT:  [ 3] .rela.text        RELA            00000000 000038 000000 18      6   1  8
-# ELF32-NEXT:  [ 4] .data             PROGBITS        00000000 000038 000000 00  WA  0   0  4
-# ELF32-NEXT:  [ 5] .bss              NOBITS          00000000 000038 000000 00  WA  0   0  4
-# ELF32-NEXT:  [ 6] .symtab           SYMTAB          00000000 000038 000020 10      7   2  8
-# ELF32-NEXT:  [ 7] .strtab           STRTAB          00000000 000058 000007 00      0   0  1
-# ELF32-NEXT:  [ 8] .shstrtab         STRTAB          00000000 00005f 00003b 00      0   0  1
+# ELF32-NEXT:  [Nr] Name              Type             Address  Off    Size   ES Flg Lk Inf Al
+# ELF32-NEXT:  [ 0]                   NULL             00000000 000000 000000 00      0   0  0
+# ELF32-NEXT:  [ 1] .text             PROGBITS         00000000 000034 000001 00  AX  0   0  4
+# ELF32-NEXT:  [ 2] .rel.text         REL              00000000 000038 000000 08      6   1  4
+# ELF32-NEXT:  [ 3] .rela.text        RELA             00000000 000038 000000 18      6   1  8
+# ELF32-NEXT:  [ 4] .data             PROGBITS         00000000 000038 000000 00  WA  0   0  4
+# ELF32-NEXT:  [ 5] .bss              NOBITS           00000000 000038 000000 00  WA  0   0  4
+# ELF32-NEXT:  [ 6] .symtab           SYMTAB           00000000 000038 000020 10      7   2  8
+# ELF32-NEXT:  [ 7] .strtab           STRTAB           00000000 000058 000007 00      0   0  1
+# ELF32-NEXT:  [ 8] .shstrtab         STRTAB           00000000 00005f 00003b 00      0   0  1
 # ELF32-NEXT:Key to Flags:
 # ELF32-NEXT:  W (write), A (alloc), X (execute), M (merge), S (strings), I (info),
 # ELF32-NEXT:  L (link order), O (extra OS processing required), G (group), T (TLS),
 # ELF32-NEXT:  C (compressed), x (unknown), o (OS specific), E (exclude),
 # ELF32-NEXT:  R (retain), p (processor specific)
 
 --- !ELF
 FileHeader:

 # RUN:   | FileCheck %s --check-prefix=ELF64
 # RUN: llvm-readobj -W --sections %t-x64.o --elf-output-style=GNU \
 # RUN:   | FileCheck %s --check-prefix=ELF64
 # RUN: llvm-readelf -W -S %t-x64.o | FileCheck %s --check-prefix=ELF64
 
 #       ELF64:There are 9 section headers, starting at offset 0xc0:
 # ELF64-EMPTY:
 # ELF64-NEXT:Section Headers:
-# ELF64-NEXT:  [Nr] Name              Type            Address          Off    Size   ES Flg Lk Inf Al
-# ELF64-NEXT:  [ 0]                   NULL            0000000000000000 000000 000000 00      0   0  0
-# ELF64-NEXT:  [ 1] .text             PROGBITS        0000000000000000 000040 000001 00  AX  0   0  4
-# ELF64-NEXT:  [ 2] .rel.text         REL             0000000000000000 000044 000000 08      6   1  4
-# ELF64-NEXT:  [ 3] .rela.text        RELA            0000000000000000 000048 000000 18      6   1  8
-# ELF64-NEXT:  [ 4] .data             PROGBITS        0000000000000000 000048 000000 00  WA  0   0  4
-# ELF64-NEXT:  [ 5] .bss              NOBITS          0000000000000000 000048 000000 00  WA  0   0  4
-# ELF64-NEXT:  [ 6] .symtab           SYMTAB          0000000000000000 000048 000030 18      7   2  8
-# ELF64-NEXT:  [ 7] .strtab           STRTAB          0000000000000000 000078 000007 00      0   0  1
-# ELF64-NEXT:  [ 8] .shstrtab         STRTAB          0000000000000000 00007f 00003b 00      0   0  1
+# ELF64-NEXT:  [Nr] Name              Type             Address          Off    Size   ES Flg Lk Inf Al
+# ELF64-NEXT:  [ 0]                   NULL             0000000000000000 000000 000000 00      0   0  0
+# ELF64-NEXT:  [ 1] .text             PROGBITS         0000000000000000 000040 000001 00  AX  0   0  4
+# ELF64-NEXT:  [ 2] .rel.text         REL              0000000000000000 000044 000000 08      6   1  4
+# ELF64-NEXT:  [ 3] .rela.text        RELA             0000000000000000 000048 000000 18      6   1  8
+# ELF64-NEXT:  [ 4] .data             PROGBITS         0000000000000000 000048 000000 00  WA  0   0  4
+# ELF64-NEXT:  [ 5] .bss              NOBITS           0000000000000000 000048 000000 00  WA  0   0  4
+# ELF64-NEXT:  [ 6] .symtab           SYMTAB           0000000000000000 000048 000030 18      7   2  8
+# ELF64-NEXT:  [ 7] .strtab           STRTAB           0000000000000000 000078 000007 00      0   0  1
+# ELF64-NEXT:  [ 8] .shstrtab         STRTAB           0000000000000000 00007f 00003b 00      0   0  1
 # ELF64-NEXT:Key to Flags:
 # ELF64-NEXT:  W (write), A (alloc), X (execute), M (merge), S (strings), I (info),
 # ELF64-NEXT:  L (link order), O (extra OS processing required), G (group), T (TLS),
 # ELF64-NEXT:  C (compressed), x (unknown), o (OS specific), E (exclude),
 # ELF64-NEXT:  R (retain), l (large), p (processor specific)
 
 ## For an EM_ARM target we print "y" for the SHF_ARM_PURECODE section flag.
 ## Check we mention it in the flag key.

llvm/test/tools/llvm-readobj/ELF/sections-no-section-header-string-table.test

 ## Check what --sections prints when there is no section header string table.
 
 # RUN: yaml2obj %s -o %t
 # RUN: llvm-readelf --sections %t \
 # RUN:   | FileCheck %s --strict-whitespace --match-full-lines --check-prefix=GNU
 # RUN: llvm-readobj --sections %t 2>&1 \
 # RUN:   | FileCheck %s -DFILE=%t --check-prefix=LLVM
 
 #      GNU:Section Headers:
-# GNU-NEXT:  [Nr] Name              Type            Address          Off    Size   ES Flg Lk Inf Al
-# GNU-NEXT:  [ 0] <no-strings>      NULL            0000000000000000 000000 000000 00      0   0  0
-# GNU-NEXT:  [ 1] <no-strings>      PROGBITS        0000000000000000 000040 000000 00      0   0  0
-# GNU-NEXT:  [ 2] <no-strings>      PROGBITS        0000000000000000 000040 000000 00      0   0  0
-# GNU-NEXT:  [ 3] <no-strings>      STRTAB          0000000000000000 000040 000001 00      0   0  1
-# GNU-NEXT:  [ 4] <no-strings>      STRTAB          0000000000000000 000041 00001d 00      0   0  1
+# GNU-NEXT:  [Nr] Name              Type             Address          Off    Size   ES Flg Lk Inf Al
+# GNU-NEXT:  [ 0] <no-strings>      NULL             0000000000000000 000000 000000 00      0   0  0
+# GNU-NEXT:  [ 1] <no-strings>      PROGBITS         0000000000000000 000040 000000 00      0   0  0
+# GNU-NEXT:  [ 2] <no-strings>      PROGBITS         0000000000000000 000040 000000 00      0   0  0
+# GNU-NEXT:  [ 3] <no-strings>      STRTAB           0000000000000000 000040 000001 00      0   0  1
+# GNU-NEXT:  [ 4] <no-strings>      STRTAB           0000000000000000 000041 00001d 00      0   0  1
 
 # LLVM:      Sections [
 # LLVM-NEXT:   Section {
 # LLVM-NEXT:     Index: 0
 # LLVM-NEXT:     Name:  (0)
 # LLVM-NEXT:     Type: SHT_NULL (0x0)
 # LLVM-NEXT:     Flags [ (0x0)
 # LLVM-NEXT:     ]

llvm/tools/llvm-readobj/ELFDumper.cpp

template <class ELFT> void GNUELFDumper<ELFT>::printSectionHeaders() {
   unsigned Bias = ELFT::Is64Bits ? 0 : 8;
   ArrayRef<Elf_Shdr> Sections = cantFail(this->Obj.sections());
   OS << "There are " << to_string(Sections.size())
      << " section headers, starting at offset "
      << "0x" << to_hexString(this->Obj.getHeader().e_shoff, false) << ":\n\n";
   OS << "Section Headers:\n";
   Field Fields[11] = {
       {"[Nr]", 2},        {"Name", 7},        {"Type", 25},
-      {"Address", 41},    {"Off", 58 - Bias}, {"Size", 65 - Bias},
-      {"ES", 72 - Bias},  {"Flg", 75 - Bias}, {"Lk", 79 - Bias},
-      {"Inf", 82 - Bias}, {"Al", 86 - Bias}};
+      {"Address", 42},    {"Off", 59 - Bias}, {"Size", 66 - Bias},
+      {"ES", 73 - Bias},  {"Flg", 76 - Bias}, {"Lk", 80 - Bias},
+      {"Inf", 83 - Bias}, {"Al", 87 - Bias}};
   for (const Field &F : Fields)
     printField(F);
   OS << "\n";
 
   StringRef SecStrTable;
   if (Expected<StringRef> SecStrTableOrErr =
           this->Obj.getSectionStringTable(Sections, this->WarningHandler))
     SecStrTable = *SecStrTableOrErr;