zig-dwarfdump

dwarfdump utility but in Zig.

Why?

Turns out the best way of learning a new file/data format is to write a parser yourself, and so here we are. Perhaps in the future we will be able to use this project as a full substitute for llvm-dwarfdump, but time will tell.

Usage

$ zig-dwarfdump --help
Usage: zig-dwarfdump [options] file

General options:
--debug-info          Display .debug_info section contents (default)
--eh-frame            Display .eh_frame section contents
--llvm-compatibility  Output is formatted exactly like llvm-dwarfdump, with no extra information
--all, -a             Display all debug info sections
--help                Display this help and exit

Example usage (MachO)

$ zig-dwarfdump main.o

__debug_info contents:
0x0000000000000000: Compile Unit: length = 0x00000000000000a1, format = DWARF32, version = 0x0004, abbr_offset = 0x0000000000000000, addr_size = 0x08 (next unit at 0x00000000000000a5)

0x000000000000000b: DW_TAG_compile_unit
                      DW_AT_producer                          (clang version 15.0.0 (git@github.com:ziglang/zig-bootstrap ae458b715c229ee49397c2c156461ababc7ed98c))
                      DW_AT_language                          (c)
                      DW_AT_name                              (main.c)
                      DW_AT_LLVM_sysroot                      (/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.3.sdk)
                      DW_AT_APPLE_sdk                         (MacOSX12.3.sdk)
                      DW_AT_stmt_list                         (0000000000000000)
                      DW_AT_comp_dir                          (/Users/kubkon/dev/zld/examples/hello_c)
                      DW_AT_low_pc                            (0000000000000000)
                      DW_AT_high_pc                           (0000000000000+48)

0x0000000000000032:   DW_TAG_variable
                        DW_AT_type                            (43)
                        DW_AT_decl_file                       (1)
                        DW_AT_decl_line                       (4)
                        DW_AT_location                        ( 3 48 0 0 0 0 0 0 0 )

0x0000000000000043:   DW_TAG_array_type
                        DW_AT_type                            (4f)

0x0000000000000048:     DW_TAG_subrange_type
                          DW_AT_type                          (56)
                          DW_AT_count                         (8)

0x000000000000004e:     NULL

0x000000000000004f:   DW_TAG_base_type
                        DW_AT_name                            (char)
                        DW_AT_encoding                        (6)
                        DW_AT_byte_size                       (1)

0x0000000000000056:   DW_TAG_base_type
                        DW_AT_name                            (__ARRAY_SIZE_TYPE__)
                        DW_AT_byte_size                       (8)
                        DW_AT_encoding                        (7)

0x000000000000005d:   DW_TAG_subprogram
                        DW_AT_low_pc                          (0000000000000000)
                        DW_AT_high_pc                         (0000000000000+48)
                        DW_AT_framebase                       ( 6d )
                        DW_AT_name                            (main)
                        DW_AT_decl_file                       (1)
                        DW_AT_decl_line                       (3)
                        DW_AT_prototyped                      (true)
                        DW_AT_type                            (93)
                        DW_AT_external                        (true)

0x0000000000000076:     DW_TAG_formal_parameter
                          DW_AT_location                      ( 91 78 )
                          DW_AT_name                          (argc)
                          DW_AT_decl_file                     (1)
                          DW_AT_decl_line                     (3)
                          DW_AT_type                          (93)

0x0000000000000084:     DW_TAG_formal_parameter
                          DW_AT_location                      ( 8f 10 )
                          DW_AT_name                          (argv)
                          DW_AT_decl_file                     (1)
                          DW_AT_decl_line                     (3)
                          DW_AT_type                          (9a)

0x0000000000000092:     NULL

0x0000000000000093:   DW_TAG_base_type
                        DW_AT_name                            (int)
                        DW_AT_encoding                        (5)
                        DW_AT_byte_size                       (4)

0x000000000000009a:   DW_TAG_pointer_type
                        DW_AT_type                            (9f)

0x000000000000009f:   DW_TAG_pointer_type
                        DW_AT_type                            (4f)

0x00000000000000a4:   NULL

$ zig-dwarfdump --eh-frame main.o
__TEXT,__eh_frame contents:

CIE:
  Length                        : 16
  Id                            : 0
  Version                       : 1
  Augmentation                  : zR
  Code Alignment Factor         : 1
  Data Alignment Factor         : -8
  Return Address Register       : 30
  Augmentation Length           : 1
  FDE Pointer Encoding          : 16
  LSDA Pointer Encoding         : 0
  Augmentation Data             : 0x10
  Initial Instructions          : 0x0c1f00

FDE:
  Length                        : 32
  CIE Pointer                   : 0x18
  PC Begin                      : 0xffffffffffffffe4
  PC Range                      : 64
  Augmentation Length           : 0
  Instructions                  : 0x440e10780e000000000000

FDE:
  Length                        : 44
  CIE Pointer                   : 0x3c
  PC Begin                      : 0xffffffffffffffc0
  PC Range                      : 56
  Augmentation Length           : 0
  Instructions                  : 0x440e30480c1d109e019d02600c1f30480e00dedd000000

Building

Use latest zig master:

$ git clone https://github.com/kubkon/zig-dwarfdump.git
$ zig build