read/macho: support Go's compression format

[ajwerner]

This PR adds support in the object crate for Go's format to compress Mach-O debug info sections. It contains two changes:

• The MachOFile now can match section names which contain both the __ and __z prefix instead of a ..
• The MachOSection now detects the presence of the __z prefix and attempts to offer decompression when it detects the section is compressed using the Go compression scheme.

A third commit adds testing. This third commit will need to be rebased to update the testfiles commit once gimli-rs/object-testfiles#14 is merged into the upstream.

Fixes #696.

[ajwerner]

TFTR!

I also manually tried this out with gimli's dwarfdump and it works.

Before:

$  cargo run --bin dwarfdump -- ../object-testfiles/macho/go-x86_64
.debug_info

.debug_types

.debug_pubnames

.debug_aranges

.debug_pubtypes

After:

$ git diff
diff --git a/Cargo.toml b/Cargo.toml
index 8eed4b2..491566f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
diff --git a/Cargo.toml b/Cargo.toml
index 8eed4b2..05faeb6 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -59,3 +59,6 @@ split-debuginfo = "packed"
 members = ["crates/examples"]
 default-members = [".", "crates/examples"]
 resolver = "2"
+
+[patch.crates-io]
+object = { path = "/Users/ajwerner/src/github.com/gimli-rs/object" }

$ cargo run --bin dwarfdump -- ../object-testfiles/macho/go-x86_64


.debug_info

UNIT<.debug_info+0x00000000>: length = 0xc99, format = Dwarf32, version = 4, address_size = 8, abbrev_offset = 0x0
< 0><0x0000000b>  DW_TAG_compile_unit
                    DW_AT_name                  internal/fmtsort
                    DW_AT_language              DW_LANG_Go
                    DW_AT_stmt_list             <.debug_line+0x00000000>
                    DW_AT_low_pc                0x01074de0
                    DW_AT_ranges                <rnglist at .debug_ranges+0x00000000>
                        [ 0] <offset-pair 0x00000000, 0x0000178c> [0x01074de0, 0x0107656c]
                    DW_AT_comp_dir              .
                    DW_AT_producer              Go cmd/compile go1.22.4; -shared regabi
                    Unknown DwAt: 10501         fmtsort
< 1><0x00000060>    DW_TAG_subprogram
                      DW_AT_name                  reflect.Value.MapRange
                      DW_AT_inline                DW_INL_inlined
                      DW_AT_decl_line             0x000007f5
                      DW_AT_external              yes
< 2><0x0000007c>      DW_TAG_formal_parameter
                        DW_AT_name                  v
                        DW_AT_variable_parameter    no
                        DW_AT_type                  <.debug_info+0x000928d2>
< 2><0x00000084>      DW_TAG_null

[ajwerner]

TFTR!

[ajwerner]

Thanks for the review!

[philipc]

I think this is good to merge after a cargo fmt.

[ajwerner]

I think this is good to merge after a cargo fmt.

Sorry for the delay, done. Thank you for the reviews.