[DebugInfo] Add a test for dumping DWARF64 CIEs and FDEs (8/8).

This adds a test to check that Length and CIE_id/CIE_pointer fields in
.debug_frame section are printed as 16-digit hex values if the records
are in the DWARF64 format.

Differential Revision: https://reviews.llvm.org/D79997

Author: igorkudrin

llvm/test/DebugInfo/X86/debug-frame-dwarf64.s

@@ -0,0 +1,40 @@
+# RUN: llvm-mc -triple x86_64 %s -filetype=obj -o - | \
+# RUN:   llvm-dwarfdump -debug-frame - | \
+# RUN:   FileCheck %s
+
+# CHECK:      00000000 0000000000000010 ffffffffffffffff CIE
+# CHECK-NEXT:   Version:               4
+# CHECK-NEXT:   Augmentation:          ""
+# CHECK-NEXT:   Address size:          8
+# CHECK-NEXT:   Segment desc size:     0
+# CHECK-NEXT:   Code alignment factor: 1
+# CHECK-NEXT:   Data alignment factor: -8
+# CHECK-NEXT:   Return address column: 16
+# CHECK-EMPTY:
+# CHECK-NEXT:   DW_CFA_nop:
+
+# CHECK:      0000001c 0000000000000018 0000000000000000 FDE cie=00000000 pc=00112233...00122233
+
+    .section .debug_frame, "", @progbits
+.LCIE:
+    .long 0xffffffff            # DWARF64 mark
+    .quad .LCIEend-.LCIEid      # Length
+.LCIEid:
+    .quad 0xffffffffffffffff    # CIE id
+    .byte 4                     # Version
+    .asciz ""                   # Augmentation
+    .byte 8                     # Address size
+    .byte 0                     # Segment selector size
+    .uleb128 1                  # Code alignment factor
+    .sleb128 -8                 # Data alignment factor
+    .uleb128 16                 # Return address register
+    .byte 0                     # DW_CFA_nop
+.LCIEend:
+.LFDE:
+    .long 0xffffffff            # DWARF64 mark
+    .quad .LFDEend-.LFDEcieptr  # Length
+.LFDEcieptr:
+    .quad .LCIE-.debug_frame    # CIE pointer
+    .quad 0x00112233            # Initial location
+    .quad 0x00010000            # Address range
+.LFDEend: