[MC][X86] Allow SHT_PROGBITS for .eh_frame on x86-64

[MaskRay]

Summary

GNU as emits SHT_PROGBITS .eh_frame by default for .cfi_* directives.
We follow x86-64 psABI and use SHT_X86_64_UNWIND for .eh_frame

Don't error for SHT_PROGBITS .eh_frame on x86-64.
This keeps compatibility for .section .eh_frame,"a",@progbits in existing assembly files.

See https://groups.google.com/d/msg/x86-64-abi/7sr4E6THl3g/zUU2UPHOAQAJ
for more discussions.

[MaskRay]

Repurpose

[joerg]

This looks much better than the in-tree state, thanks.

[MaskRay]

Fix test. Fix title.

[joerg]

Can you add a variation with .pushsection for @progbits and @nobits? Otherwise LGTM.

[MaskRay]

In D76151#1948225, @joerg wrote:

Can you add a variation with .pushsection for @progbits and @nobits? Otherwise LGTM.

I think a .pushsection test will be redundant as it shares code with .section.

I am waiting for the resolution https://groups.google.com/forum/#!topic/x86-64-abi/7sr4E6THl3g , otherwise I cannot say "x86-64 psABI allows SHT_PROGBITS as an alternative section type" :/

[joerg]

We tend to test push .section and .pushsection in this file, so it would be nice to continue doing that.

[MaskRay]

Mention GNU as but drop mention of x86-64 psABI change (which hasn't happened yet and may not happen)

llvm/lib/MC/MCObjectFileInfo.cpp

case Triple::hexagon:
     FDECFIEncoding =
         PositionIndependent ? dwarf::DW_EH_PE_pcrel : dwarf::DW_EH_PE_absptr;
     break;
   default:
     FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
     break;
   }
 
-  unsigned EHSectionType = T.getArch() == Triple::x86_64
-                               ? ELF::SHT_X86_64_UNWIND
-                               : ELF::SHT_PROGBITS;
-
+  unsigned EHSectionType = ELF::SHT_PROGBITS;
+  unsigned EHSectionFlags = ELF::SHF_ALLOC;
   // Solaris requires different flags for .eh_frame to seemingly every other
   // platform.
-  unsigned EHSectionFlags = ELF::SHF_ALLOC;
-  if (T.isOSSolaris() && T.getArch() != Triple::x86_64)
+  if (T.isOSSolaris()) {
+    if (T.getArch() == Triple::x86_64)
+      EHSectionType = ELF::SHT_X86_64_UNWIND;
+    else
       EHSectionFlags |= ELF::SHF_WRITE;
+  }
 
   // ELF
   BSSSection = Ctx->getELFSection(".bss", ELF::SHT_NOBITS,
                                   ELF::SHF_WRITE | ELF::SHF_ALLOC);
 
   TextSection = Ctx->getELFSection(".text", ELF::SHT_PROGBITS,
                                    ELF::SHF_EXECINSTR | ELF::SHF_ALLOC);
 

llvm/lib/MC/MCParser/ELFAsmParser.cpp

if (const MCSectionELF *Section =
         GroupName = Group->getName();
         Flags |= ELF::SHF_GROUP;
       }
   }
 
   MCSectionELF *Section = getContext().getELFSection(
       SectionName, Type, Flags, Size, GroupName, UniqueID, LinkedToSym);
   getStreamer().SwitchSection(Section, Subsection);
-  if (Section->getType() != Type)
+  // x86-64 psABI used to require .eh_frame to be SHT_X86_64_UNWIND and clang
+  // used to produce SHT_X86_64_UNWIND (since r252300). Special case the
+  // obsoleted type for compatibility with .section .eh_frame,"a",@unwind
+  if (Section->getType() != Type && Type != ELF::SHT_X86_64_UNWIND)
     Error(loc, "changed section type for " + SectionName + ", expected: 0x" +
                    utohexstr(Section->getType()));
   if (Section->getFlags() != Flags)
     Error(loc, "changed section flags for " + SectionName + ", expected: 0x" +
                    utohexstr(Section->getFlags()));
   if (Section->getEntrySize() != Size)
     Error(loc, "changed section entsize for " + SectionName +
                    ", expected: " + Twine(Section->getEntrySize()));

llvm/test/CodeGen/X86/eh_frame.ll

 ; RUN: llc < %s -mtriple x86_64-unknown-linux-gnu | FileCheck -check-prefix=STATIC %s
 ; RUN: llc < %s -mtriple x86_64-unknown-linux-gnu -relocation-model=pic | FileCheck -check-prefix=PIC %s
 
 @__FRAME_END__ = constant [1 x i32] zeroinitializer, section ".eh_frame"
 
 @foo = external global i32
 @bar1 = constant i8* bitcast (i32* @foo to i8*), section "my_bar1", align 8
 
 
-; STATIC: .section  .eh_frame,"a",@unwind
+; STATIC: .section  .eh_frame,"a",@progbits
 ; STATIC: .section  my_bar1,"a",@progbits
 
-; PIC:  .section  .eh_frame,"a",@unwind
+; PIC:  .section  .eh_frame,"a",@progbits
 ; PIC:  .section  my_bar1,"aw",@progbits

llvm/test/MC/ELF/cfi-adjust-cfa-offset.s

.cfi_endproc
         .cfi_startproc
   nop
   .cfi_adjust_cfa_offset 4
   .cfi_endproc
 
 // CHECK:        Section {
 // CHECK:          Index:
 // CHECK:          Name: .eh_frame
-// CHECK-NEXT:     Type: SHT_X86_64_UNWIND
+// CHECK-NEXT:     Type: SHT_PROGBITS
 // CHECK-NEXT:     Flags [
 // CHECK-NEXT:       SHF_ALLOC
 // CHECK-NEXT:     ]
 // CHECK-NEXT:     Address: 0x0
 // CHECK-NEXT:     Offset: 0x50
 // CHECK-NEXT:     Size: 96
 // CHECK-NEXT:     Link: 0
 // CHECK-NEXT:     Info: 0

llvm/test/MC/ELF/cfi-advance-loc2.s

 // RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | llvm-readobj -S --sr --sd | FileCheck %s
 
 // test that this produces a correctly encoded cfi_advance_loc2
 
 f:
   .cfi_startproc
         nop
         .zero 255, 0x90
   .cfi_def_cfa_offset 8
         nop
   .cfi_endproc
 
 // CHECK:        Section {
 // CHECK:          Name: .eh_frame
-// CHECK-NEXT:     Type: SHT_X86_64_UNWIND
+// CHECK-NEXT:     Type: SHT_PROGBITS
 // CHECK-NEXT:     Flags [
 // CHECK-NEXT:       SHF_ALLOC
 // CHECK-NEXT:     ]
 // CHECK-NEXT:     Address: 0x0
 // CHECK-NEXT:     Offset: 0x148
 // CHECK-NEXT:     Size: 48
 // CHECK-NEXT:     Link: 0
 // CHECK-NEXT:     Info: 0

llvm/test/MC/ELF/cfi-def-cfa-offset.s

 // RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | llvm-readobj -S --sr --sd | FileCheck %s
 
 f:
   .cfi_startproc
   subq  $8, %rsp
   .cfi_def_cfa_offset 16
         nop
   addq  $8, %rsp
   .cfi_def_cfa_offset 8
   ret
   .cfi_endproc
 
 // CHECK:        Section {
 // CHECK:          Index:
 // CHECK:          Name: .eh_frame
-// CHECK-NEXT:     Type: SHT_X86_64_UNWIND
+// CHECK-NEXT:     Type: SHT_PROGBITS
 // CHECK-NEXT:     Flags [
 // CHECK-NEXT:       SHF_ALLOC
 // CHECK-NEXT:     ]
 // CHECK-NEXT:     Address: 0x0
 // CHECK-NEXT:     Offset: 0x50
 // CHECK-NEXT:     Size: 48
 // CHECK-NEXT:     Link: 0
 // CHECK-NEXT:     Info: 0

llvm/test/MC/ELF/cfi-def-cfa-register.s

 // RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | llvm-readobj -S --sr --sd | FileCheck %s
 
 f:
   .cfi_startproc
         nop
   .cfi_def_cfa_register 6
         nop
   .cfi_endproc
 
 // CHECK:        Section {
 // CHECK:          Name: .eh_frame
-// CHECK-NEXT:     Type: SHT_X86_64_UNWIND
+// CHECK-NEXT:     Type: SHT_PROGBITS
 // CHECK-NEXT:     Flags [
 // CHECK-NEXT:       SHF_ALLOC
 // CHECK-NEXT:     ]
 // CHECK-NEXT:     Address: 0x0
 // CHECK-NEXT:     Offset: 0x48
 // CHECK-NEXT:     Size: 48
 // CHECK-NEXT:     Link: 0
 // CHECK-NEXT:     Info: 0

llvm/test/MC/ELF/cfi-def-cfa.s

 // RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | llvm-readobj -S --sr --sd | FileCheck %s
 
 f:
   .cfi_startproc
         nop
   .cfi_def_cfa 7, 8
         nop
   .cfi_endproc
 
 // CHECK:        Section {
 // CHECK:          Name: .eh_frame
-// CHECK-NEXT:     Type: SHT_X86_64_UNWIND
+// CHECK-NEXT:     Type: SHT_PROGBITS
 // CHECK-NEXT:     Flags [
 // CHECK-NEXT:       SHF_ALLOC
 // CHECK-NEXT:     ]
 // CHECK-NEXT:     Address: 0x0
 // CHECK-NEXT:     Offset: 0x48
 // CHECK-NEXT:     Size: 48
 // CHECK-NEXT:     Link: 0
 // CHECK-NEXT:     Info: 0

llvm/test/MC/ELF/cfi-escape.s

 // RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | llvm-readobj -S --sr --sd | FileCheck %s
 
 f:
   .cfi_startproc
         nop
   .cfi_escape 0x15, 7, 0x7f # DW_CFA_val_offset_sf, %esp, 8/-8
         nop
   .cfi_endproc
 
 // CHECK:        Section {
 // CHECK:          Index:
 // CHECK:          Name: .eh_frame
-// CHECK-NEXT:     Type: SHT_X86_64_UNWIND
+// CHECK-NEXT:     Type: SHT_PROGBITS
 // CHECK-NEXT:     Flags [
 // CHECK-NEXT:       SHF_ALLOC
 // CHECK-NEXT:     ]
 // CHECK-NEXT:     Address: 0x0
 // CHECK-NEXT:     Offset: 0x48
 // CHECK-NEXT:     Size: 48
 // CHECK-NEXT:     Link: 0
 // CHECK-NEXT:     Info: 0

llvm/test/MC/ELF/cfi-large-model.s

 // REQUIRES: powerpc-registered-target
 // REQUIRES: x86-registered-target
 // RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu -large-code-model %s \
 // RUN:   -o - | llvm-readobj -S --sd | FileCheck --check-prefix=CHECK-X86 %s
 // RUN: llvm-mc -filetype=obj -triple powerpc64le-linux-gnu -large-code-model %s \
 // RUN:   -o - | llvm-readobj -S --sd | FileCheck --check-prefix=CHECK-PPC %s
 
 
 // CHECK-X86:      Section {
 // CHECK-X86:        Index:
 // CHECK-X86:        Name: .eh_frame
-// CHECK-X86-NEXT:   Type: SHT_X86_64_UNWIND
+// CHECK-X86-NEXT:   Type: SHT_PROGBITS
 // CHECK-X86-NEXT:   Flags [
 // CHECK-X86-NEXT:     SHF_ALLOC
 // CHECK-X86-NEXT:   ]
 // CHECK-X86-NEXT:   Address: 0x0
 // CHECK-X86-NEXT:   Offset: 0x40
 // CHECK-X86-NEXT:   Size: 56
 // CHECK-X86-NEXT:   Link: 0
 // CHECK-X86-NEXT:   Info: 0

llvm/test/MC/ELF/cfi-offset.s

 // RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | llvm-readobj -S --sr --sd | FileCheck %s
 
 f:
   .cfi_startproc
         nop
   .cfi_offset %rbp, -16
         nop
   .cfi_endproc
 
 // CHECK:        Section {
 // CHECK:          Name: .eh_frame
-// CHECK-NEXT:     Type: SHT_X86_64_UNWIND
+// CHECK-NEXT:     Type: SHT_PROGBITS
 // CHECK-NEXT:     Flags [
 // CHECK-NEXT:       SHF_ALLOC
 // CHECK-NEXT:     ]
 // CHECK-NEXT:     Address: 0x0
 // CHECK-NEXT:     Offset: 0x48
 // CHECK-NEXT:     Size: 48
 // CHECK-NEXT:     Link: 0
 // CHECK-NEXT:     Info: 0

llvm/test/MC/ELF/cfi-register.s

 // RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | llvm-readobj -S --sr --sd | FileCheck %s
 
 f:
   .cfi_startproc
         nop
   .cfi_register %rbp, %rax
         nop
   .cfi_endproc
 
 // CHECK:        Section {
 // CHECK:          Index:
 // CHECK:          Name: .eh_frame
-// CHECK-NEXT:     Type: SHT_X86_64_UNWIND
+// CHECK-NEXT:     Type: SHT_PROGBITS
 // CHECK-NEXT:     Flags [
 // CHECK-NEXT:       SHF_ALLOC
 // CHECK-NEXT:     ]
 // CHECK-NEXT:     Address: 0x0
 // CHECK-NEXT:     Offset: 0x48
 // CHECK-NEXT:     Size: 48
 // CHECK-NEXT:     Link: 0
 // CHECK-NEXT:     Info: 0

llvm/test/MC/ELF/cfi-rel-offset.s

.cfi_startproc
         .cfi_def_cfa_offset 16
         nop
         .cfi_rel_offset 6,0
   .cfi_endproc
 
 // CHECK:        Section {
 // CHECK:          Index:
 // CHECK:          Name: .eh_frame
-// CHECK-NEXT:     Type: SHT_X86_64_UNWIND
+// CHECK-NEXT:     Type: SHT_PROGBITS
 // CHECK-NEXT:     Flags [
 // CHECK-NEXT:       SHF_ALLOC
 // CHECK-NEXT:     ]
 // CHECK-NEXT:     Address: 0x0
 // CHECK-NEXT:     Offset: 0x48
 // CHECK-NEXT:     Size: 64
 // CHECK-NEXT:     Link: 0
 // CHECK-NEXT:     Info: 0

llvm/test/MC/ELF/cfi-rel-offset2.s

 // RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | llvm-readobj -S --sr --sd | FileCheck %s
 
 f:
   .cfi_startproc
         nop
         .cfi_rel_offset 6,16
   .cfi_endproc
 
 // CHECK:        Section {
 // CHECK:          Index:
 // CHECK:          Name: .eh_frame
-// CHECK-NEXT:     Type: SHT_X86_64_UNWIND
+// CHECK-NEXT:     Type: SHT_PROGBITS
 // CHECK-NEXT:     Flags [
 // CHECK-NEXT:       SHF_ALLOC
 // CHECK-NEXT:     ]
 // CHECK-NEXT:     Address: 0x0
 // CHECK-NEXT:     Offset: 0x48
 // CHECK-NEXT:     Size: 48
 // CHECK-NEXT:     Link: 0
 // CHECK-NEXT:     Info: 0

llvm/test/MC/ELF/cfi-remember.s

 // RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | llvm-readobj -S --sr --sd | FileCheck %s
 
 f:
   .cfi_startproc
         nop
   .cfi_remember_state
         nop
   .cfi_restore_state
         nop
   .cfi_endproc
 
 // CHECK:        Section {
 // CHECK:          Index:
 // CHECK:          Name: .eh_frame
-// CHECK-NEXT:     Type: SHT_X86_64_UNWIND
+// CHECK-NEXT:     Type: SHT_PROGBITS
 // CHECK-NEXT:     Flags [
 // CHECK-NEXT:       SHF_ALLOC
 // CHECK-NEXT:     ]
 // CHECK-NEXT:     Address: 0x0
 // CHECK-NEXT:     Offset: 0x48
 // CHECK-NEXT:     Size: 48
 // CHECK-NEXT:     Link: 0
 // CHECK-NEXT:     Info: 0

llvm/test/MC/ELF/cfi-restore.s

 // RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | llvm-readobj -S --sr --sd | FileCheck %s
 
 f:
   .cfi_startproc
         nop
   .cfi_restore %rbp
         nop
   .cfi_endproc
 
 // CHECK:        Section {
 // CHECK:          Index:
 // CHECK:          Name: .eh_frame
-// CHECK-NEXT:     Type: SHT_X86_64_UNWIND
+// CHECK-NEXT:     Type: SHT_PROGBITS
 // CHECK-NEXT:     Flags [
 // CHECK-NEXT:       SHF_ALLOC
 // CHECK-NEXT:     ]
 // CHECK-NEXT:     Address: 0x0
 // CHECK-NEXT:     Offset: 0x48
 // CHECK-NEXT:     Size: 48
 // CHECK-NEXT:     Link: 0
 // CHECK-NEXT:     Info: 0

llvm/test/MC/ELF/cfi-same-value.s

 // RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | llvm-readobj -S --sr --sd | FileCheck %s
 
 f:
   .cfi_startproc
         nop
         .cfi_same_value 6
         nop
   .cfi_endproc
 
 // CHECK:        Section {
 // CHECK:          Index:
 // CHECK:          Name: .eh_frame
-// CHECK-NEXT:     Type: SHT_X86_64_UNWIND
+// CHECK-NEXT:     Type: SHT_PROGBITS
 // CHECK-NEXT:     Flags [
 // CHECK-NEXT:       SHF_ALLOC
 // CHECK-NEXT:     ]
 // CHECK-NEXT:     Address: 0x0
 // CHECK-NEXT:     Offset: 0x48
 // CHECK-NEXT:     Size: 48
 // CHECK-NEXT:     Link: 0
 // CHECK-NEXT:     Info: 0

llvm/test/MC/ELF/cfi-signal-frame.s

 // RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | llvm-readobj -S --sd | FileCheck %s
 
 f:
         .cfi_startproc
         .cfi_signal_frame
         .cfi_endproc
 
 g:
         .cfi_startproc
         .cfi_endproc
 
 // CHECK:        Section {
 // CHECK:          Name: .eh_frame
-// CHECK-NEXT:     Type: SHT_X86_64_UNWIND
+// CHECK-NEXT:     Type: SHT_PROGBITS
 // CHECK-NEXT:     Flags [
 // CHECK-NEXT:       SHF_ALLOC
 // CHECK-NEXT:     ]
 // CHECK-NEXT:     Address: 0x0
 // CHECK-NEXT:     Offset: 0x40
 // CHECK-NEXT:     Size: 88
 // CHECK-NEXT:     Link: 0
 // CHECK-NEXT:     Info: 0

llvm/test/MC/ELF/cfi-undefined.s

 // RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | llvm-readobj -S --sr --sd | FileCheck %s
 
 f:
   .cfi_startproc
         nop
   .cfi_undefined %rbp
         nop
   .cfi_endproc
 
 // CHECK:        Section {
 // CHECK:          Index:
 // CHECK:          Name: .eh_frame
-// CHECK-NEXT:     Type: SHT_X86_64_UNWIND
+// CHECK-NEXT:     Type: SHT_PROGBITS
 // CHECK-NEXT:     Flags [
 // CHECK-NEXT:       SHF_ALLOC
 // CHECK-NEXT:     ]
 // CHECK-NEXT:     Address: 0x0
 // CHECK-NEXT:     Offset: 0x48
 // CHECK-NEXT:     Size: 48
 // CHECK-NEXT:     Link: 0
 // CHECK-NEXT:     Info: 0

llvm/test/MC/ELF/cfi-window-save.s

 // RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | llvm-readobj -S --sr --sd | FileCheck %s
 
 # Should use SPARC as the target to test this. However, SPARC does not
 # use MC yet.
 
 f:
         .cfi_startproc
         nop
         .cfi_window_save
         nop
         .cfi_endproc
 
 // CHECK:        Section {
 // CHECK:          Name: .eh_frame
-// CHECK-NEXT:     Type: SHT_X86_64_UNWIND
+// CHECK-NEXT:     Type: SHT_PROGBITS
 // CHECK-NEXT:     Flags [
 // CHECK-NEXT:       SHF_ALLOC
 // CHECK-NEXT:     ]
 // CHECK-NEXT:     Address: 0x0
 // CHECK-NEXT:     Offset: 0x48
 // CHECK-NEXT:     Size: 48
 // CHECK-NEXT:     Link: 0
 // CHECK-NEXT:     Info: 0

llvm/test/MC/ELF/cfi-zero-addr-delta.s

f:
   .cfi_def_cfa_offset 8
         nop
   .cfi_restore_state
         nop
   .cfi_endproc
 
 // CHECK:        Section {
 // CHECK:          Name: .eh_frame
-// CHECK-NEXT:     Type: SHT_X86_64_UNWIND
+// CHECK-NEXT:     Type: SHT_PROGBITS
 // CHECK-NEXT:     Flags [
 // CHECK-NEXT:       SHF_ALLOC
 // CHECK-NEXT:     ]
 // CHECK-NEXT:     Address: 0x0
 // CHECK-NEXT:     Offset: 0x48
 // CHECK-NEXT:     Size: 56
 // CHECK-NEXT:     Link: 0
 // CHECK-NEXT:     Info: 0

llvm/test/MC/ELF/cfi.s

 f37:
         .cfi_startproc simple
         nop
         .cfi_endproc
 
 // CHECK:        Section {
 // CHECK:          Index:
 // CHECK:          Name: .eh_frame
-// CHECK-NEXT:     Type: SHT_X86_64_UNWIND
+// CHECK-NEXT:     Type: SHT_PROGBITS
 // CHECK-NEXT:     Flags [
 // CHECK-NEXT:       SHF_ALLOC
 // CHECK-NEXT:     ]
 // CHECK-NEXT:     Address: 0x0
 // CHECK-NEXT:     Offset: 0x68
 // CHECK-NEXT:     Size: 1776
 // CHECK-NEXT:     Link: 0
 // CHECK-NEXT:     Info: 0

llvm/test/MC/ELF/section-type-changed.s

 # RUN: not llvm-mc -triple=x86_64 %s -o /dev/null 2>&1 | FileCheck %s --implicit-check-not=error:
 
 .section .foo,"a",@progbits
 
 # CHECK: {{.*}}.s:[[# @LINE+1]]:1: error: changed section type for .foo, expected: 0x1
 .section .foo,"a",@init_array
 
 # CHECK: {{.*}}.s:[[# @LINE+1]]:1: error: changed section type for .foo, expected: 0x1
 .pushsection .foo,"a",@nobits
 
+# clang used to produce SHT_X86_64_UNWIND for .eh_frame . We don't want to
+# error on them. For simplicity, we allow all sections names.
+.pushsection .foo,"a",@unwind
+
 .pushsection .foo,"a",@progbits

llvm/test/MC/ELF/section.s

 .section        .text.bar,"axMG",@progbits,42,bar,comdat
 
 // Test that the default values are not used
 
 .section .eh_frame,"a",@unwind
 
 // CHECK:        Section {
 // CHECK:          Name: .eh_frame
-// CHECK-NEXT:     Type: SHT_X86_64_UNWIND
+// CHECK-NEXT:     Type: SHT_PROGBITS
 // CHECK-NEXT:     Flags [
 // CHECK-NEXT:       SHF_ALLOC
 // CHECK-NEXT:     ]
 // CHECK-NEXT:     Address: 0x0
 // CHECK-NEXT:     Offset:
 // CHECK-NEXT:     Size: 0
 // CHECK-NEXT:     Link: 0
 // CHECK-NEXT:     Info: 0