DWARFDebugLoclists: Make it possible to read relocated addresses

Summary:
Handling relocations was not needed when the loclists section was a
DWO-only thing. But since DWARF5, it is possible to use it in regular
objects too, and the standard permits embedding addresses into the
section directly. These addresses need to be relocated in unlinked
files.

Reviewers: JDevlieghere, dblaikie, probinson

Subscribers: aprantl, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68271

1 files changed, 120 insertions, 0 deletions

diff --git a/llvm/test/tools/llvm-dwarfdump/X86/debug_loclists.s b/llvm/test/tools/llvm-dwarfdump/X86/debug_loclists.s
new file mode 100644
index 00000000000..a44080eb994
--- /dev/null
+++ b/llvm/test/tools/llvm-dwarfdump/X86/debug_loclists.s
@@ -0,0 +1,120 @@
+# RUN: llvm-mc %s -filetype obj -triple x86_64-pc-linux -o %t
+# RUN: llvm-dwarfdump %t | FileCheck %s
+
+
+# CHECK:          DW_AT_location        (0x0000000c
+# CHECK-NEXT:        Addr idx 0 (w/ length 1): DW_OP_reg0 RAX
+# CHECK-NEXT:        [0x0000000000000001, 0x0000000000000002): DW_OP_reg1 RDX
+# CHECK-NEXT:        [0x0000000000000002, 0x0000000000000003): DW_OP_reg2 RCX
+# CHECK-NEXT:        [0x0000000000000003, 0x0000000000000004): DW_OP_reg3 RBX
+# CHECK-NEXT:        Addr idx 57005 (w/ length 1): DW_OP_reg4 RSI)
+
+
+        .text
+f:                                      # @f
+.Lf0:
+        nop
+.Lf1:
+        nop
+.Lf2:
+        nop
+.Lf3:
+        nop
+.Lf4:
+.Lfend:
+                                        # -- End function
+        .section        .debug_loclists,"",@progbits
+        .long   .Ldebug_loclist_table_end0-.Ldebug_loclist_table_start0 # Length
+.Ldebug_loclist_table_start0:
+        .short  5                       # Version
+        .byte   8                       # Address size
+        .byte   0                       # Segment selector size
+        .long   0                       # Offset entry count
+.Lloclists_table_base0:
+.Ldebug_loc0:
+        .byte   3                       # DW_LLE_startx_length
+        .uleb128 0                      #   start idx
+        .uleb128 .Lf1-.Lf0              #   length
+        .byte   1                       # Loc expr size
+        .byte   80                      # super-register DW_OP_reg0
+        .byte   4                       # DW_LLE_offset_pair
+        .uleb128 .Lf1-.Lf0              #   starting offset
+        .uleb128 .Lf2-.Lf0              #   ending offset
+        .byte   1                       # Loc expr size
+        .byte   81                      # super-register DW_OP_reg1
+        .byte   8                       # DW_LLE_start_length
+        .quad   .Lf2                    #   starting offset
+        .uleb128 .Lf3-.Lf2              #   length
+        .byte   1                       # Loc expr size
+        .byte   82                      # super-register DW_OP_reg2
+        .byte   6                       # DW_LLE_base_address
+        .quad   .Lf3                    #   base address
+        .byte   4                       # DW_LLE_offset_pair
+        .uleb128 .Lf3-.Lf3              #   starting offset
+        .uleb128 .Lf4-.Lf3              #   ending offset
+        .byte   1                       # Loc expr size
+        .byte   83                      # super-register DW_OP_reg3
+        .byte   3                       # DW_LLE_startx_length
+        .uleb128 0xdead                 #   start idx
+        .uleb128 .Lf1-.Lf0              #   length
+        .byte   1                       # Loc expr size
+        .byte   84                      # super-register DW_OP_reg4
+        .byte   0                       # DW_LLE_end_of_list
+.Ldebug_loclist_table_end0:
+
+        .section        .debug_abbrev,"",@progbits
+        .byte   1                       # Abbreviation Code
+        .byte   17                      # DW_TAG_compile_unit
+        .byte   1                       # DW_CHILDREN_yes
+        .byte   115                     # DW_AT_addr_base
+        .byte   23                      # DW_FORM_sec_offset
+        .ascii  "\214\001"              # DW_AT_loclists_base
+        .byte   23                      # DW_FORM_sec_offset
+        .byte   0                       # EOM(1)
+        .byte   0                       # EOM(2)
+        .byte   2                       # Abbreviation Code
+        .byte   46                      # DW_TAG_subprogram
+        .byte   1                       # DW_CHILDREN_yes
+        .byte   17                      # DW_AT_low_pc
+        .byte   27                      # DW_FORM_addrx
+        .byte   18                      # DW_AT_high_pc
+        .byte   6                       # DW_FORM_data4
+        .byte   0                       # EOM(1)
+        .byte   0                       # EOM(2)
+        .byte   3                       # Abbreviation Code
+        .byte   5                       # DW_TAG_formal_parameter
+        .byte   0                       # DW_CHILDREN_no
+        .byte   2                       # DW_AT_location
+        .byte   23                      # DW_FORM_sec_offset
+        .byte   0                       # EOM(1)
+        .byte   0                       # EOM(2)
+        .byte   0                       # EOM(3)
+        .section        .debug_info,"",@progbits
+.Lcu_begin0:
+        .long   .Ldebug_info_end0-.Ldebug_info_start0 # Length of Unit
+.Ldebug_info_start0:
+        .short  5                       # DWARF version number
+        .byte   1                       # DWARF Unit Type
+        .byte   8                       # Address Size (in bytes)
+        .long   .debug_abbrev           # Offset Into Abbrev. Section
+        .byte   1                       # Abbrev [1] 0xc:0x3c DW_TAG_compile_unit
+        .long   .Laddr_table_base0      # DW_AT_addr_base
+        .long   .Lloclists_table_base0  # DW_AT_loclists_base
+        .byte   2                       # Abbrev [2] 0x27:0x1c DW_TAG_subprogram
+        .byte   0                       # DW_AT_low_pc
+        .long   .Lfend-.Lf0             # DW_AT_high_pc
+        .byte   3                       # Abbrev [3] 0x36:0xc DW_TAG_formal_parameter
+        .long   .Ldebug_loc0            # DW_AT_location
+        .byte   0                       # End Of Children Mark
+        .byte   0                       # End Of Children Mark
+.Ldebug_info_end0:
+
+        .section        .debug_addr,"",@progbits
+        .long   .Ldebug_addr_end0-.Ldebug_addr_start0 # Length of contribution
+.Ldebug_addr_start0:
+        .short  5                       # DWARF version number
+        .byte   8                       # Address size
+        .byte   0                       # Segment selector size
+.Laddr_table_base0:
+        .quad   .Lf0
+.Ldebug_addr_end0: