go/src/debug/dwarf/testdata, branch makepkg

debug/dwarf: fix problem with DWARF 5 and Seek method

2025-03-10T16:05:58Z

When clients use debug/dwarf to examine DWARF 5 binaries, we can run into problems when the Seek() method is used to skip ahead from a DIE in one compilation unit to a DIE in another unit. The problem here is that it is common for DWARF 5 comp units to have attributes (ex: DW_AT_addr_base) whose value must be applied as an offset when reading certain forms (ex: DW_FORM_addrx) within that unit. The existing implementation didn't have a good way to recover these attrs following the Seek call, and had to essentially punt in this case, resulting in incorrect attr values. This patch adds new support for reading and caching the key comp unit DIE attributes (DW_AT_addr_base, DW_AT_loclists_base, etc) prior to visiting any of the DIE entries in a unit, storing the cache values of these attrs the main table of units. This base attribute reading/caching behavior also happens (where needed) after Seek calls. Should resolve delve issue 3861. Supercedes Go pull request 70400. Updates #26379. Fixes #57046. Change-Id: I536a57e2ba4fc55132d91c7f36f67a91ac408dc3 Reviewed-on: https://go-review.googlesource.com/c/go/+/655976 Reviewed-by: Alessandro Arzilli Reviewed-by: Cherry Mui Reviewed-by: Ian Lance Taylor LUCI-TryBot-Result: Go LUCI

debug/elf: support zstd compression

2023-04-18T20:34:36Z

Test cases added to debug/dwarf because that is where it matters in practice. The new test binary line-gcc-zstd.elf built with gcc -g -no-pie -Wl,--compress-debug-sections=zstd line[12].c using gcc (Debian 12.2.0-10) 12.2.0 with a development version of the GNU binutils. Fixes #55107 Change-Id: I48507c96902e1f83a174e5647b5cc403d965b52b Reviewed-on: https://go-review.googlesource.com/c/go/+/473256 TryBot-Result: Gopher Robot Reviewed-by: Ian Lance Taylor Run-TryBot: Ian Lance Taylor Run-TryBot: Ian Lance Taylor Auto-Submit: Ian Lance Taylor Reviewed-by: Than McIntosh

debug/dwarf: fix problems with handling of bit offsets for bitfields

2022-01-28T20:07:54Z

This patch reworks the handling of the DWARF DW_AT_bit_offset and DW_AT_data_bit_offset attributes to resolve problems arising from a previous related change (CL 328709). In CL 328709 the DWARF type reader was updated to look for and use the DW_AT_data_bit_offset attribute for structure fields, handling the value of the attribute in the same way as for DW_AT_bit_offset. This caused problems for clients, since the two attributes have very different semantics. This CL effectively reverts CL 328709 and moves to a scheme in which we detect and report the two attributes separately/independently. This patch also corrects a problem in the DWARF type reader in the code that detects and fixes up the type of struct fields corresponding to zero-length arrays; the code in question was testing the DW_AT_bit_offset attribute value but assuming DW_AT_data_bit_offset semantics, meaning that it would fail to fix up cases such as typedef struct another_struct { unsigned short quix; int xyz[0]; unsigned x:1; long long array[40]; } t; The code in question has been changed to avoid using BitOffset and instead consider only ByteOffset and BitSize. Fixes #50685. Updates #46784. Change-Id: Ic15ce01c851af38ebd81af827973ec49badcab6f Reviewed-on: https://go-review.googlesource.com/c/go/+/380714 Trust: Than McIntosh Run-TryBot: Than McIntosh TryBot-Result: Gopher Robot Reviewed-by: Ian Lance Taylor

debug/dwarf: check for DWARFv4 AttrDataBitOffset value

2021-09-02T19:56:24Z

AttrBitOffset is deprecated (but reserved) in DWARFv4. This fix adds logic to check the new AttrDataBitOffset attribute if AttrBitOffset attribute is not present. Fixes #46784 Change-Id: I7406dcaa4c98e95df72361fd4462c39e6be8879d GitHub-Last-Rev: 5aa10d04910a09538320b4de8fbd8a1f5fd8c17d GitHub-Pull-Request: golang/go#46790 Reviewed-on: https://go-review.googlesource.com/c/go/+/328709 Run-TryBot: Than McIntosh TryBot-Result: Go Bot Reviewed-by: Ian Lance Taylor Trust: Michael Knyszek

debug/dwarf: support DW_FORM_rnglistx aka formRnglistx

2021-03-17T00:54:09Z

Change-Id: I7df915978af3488f46a27595a1b04d0d33f81f7b Reviewed-on: https://go-review.googlesource.com/c/go/+/302369 Trust: Ian Lance Taylor Run-TryBot: Ian Lance Taylor TryBot-Result: Go Bot Reviewed-by: Than McIntosh

debug/dwarf: don't try to parse addr/rnglists header

2020-12-14T18:06:06Z

In an executable, the debug_addr and debug_rnglists sections are assembled by concatenating the input sections, and each input section has a header, and each header may have different attributes. So just parsing the single header isn't right. Parsing the header is not necessary to handle offsets into these sections which is all we do. Looking at the header is also problematic because GCC with -gsplit-dwarf when using DWARF versions 2 through 4 emits a .debug_addr section, but it has no header. The header was only added for DWARF 5. So we can't parse the header at all for that case, and we can't even detect that case in general. This CL also fixes SeekPC with addrx and strx formats, by not using the wrong compilation unit to find the address or string base. To make that work when parsing the compilation unit itself, we add support for delay the resolution of those values until we know the base. New test binaries built with gcc -gdwarf-5 -no-pie debug/dwarf/testdata/line[12].c (gcc (Debian 10.2.0-15) 10.2.0) clang -gdwarf-5 -no-pie debug/dwarf/testdata/line[12].c (clang version 9.0.1-14) Change-Id: I66783e0eded629bf80c467767f781164d344a54d Reviewed-on: https://go-review.googlesource.com/c/go/+/277233 Trust: Ian Lance Taylor Reviewed-by: Than McIntosh

debug/dwarf: add support for DWARFv5 to (*Data).Ranges

2020-10-24T04:11:41Z

Updates the (*Data).Ranges method to work with DWARFv5 which uses the new debug_rnglists section instead of debug_ranges. This does not include supporting DW_FORM_rnglistx. General support for DWARFv5 was added by CL 175138. Change-Id: I01f919a865616a3ff12f5bf649c2c9abf89fcf52 Reviewed-on: https://go-review.googlesource.com/c/go/+/236657 Run-TryBot: Ian Lance Taylor TryBot-Result: Go Bot Reviewed-by: Ian Lance Taylor Trust: Emmanuel Odeke

debug/dwarf: more graceful handling of unsupported types

2019-03-15T17:33:46Z

Enhance the type decoder to do a better job handling unknown type tags. DWARF has a number of type DIEs that this package doesn't handle (things like "pointer to member" types in C++); avoid crashing for such types, but instead return a placeholder "UnsupportedType" object (this idea suggested by Austin). This provides a compromise between implementing the entire kitchen sink and simply returning an error outright on any unknown type DIE. Fixes #29601. Change-Id: I2eeffa094c86ef3a2c358ee42e8e629d74cec2ed Reviewed-on: https://go-review.googlesource.com/c/go/+/158797 Reviewed-by: Brad Fitzpatrick Run-TryBot: Brad Fitzpatrick TryBot-Result: Gobot Gobot

debug/dwarf: heuristically handle both UNIX and Windows paths

2017-05-26T14:35:20Z

Currently debug/dwarf assumes all paths in line tables will be UNIX-style paths, which obviously isn't the case for binaries built on Windows. However, we can't simply switch from the path package to the filepath package because we don't know that we're running on the same host type that built the binary and we want this to work even if we're not. This is essentially the approach taken by GDB, which treats paths in accordance with the system GDB itself is compiled for. In fact, we can't even guess the compilation system from the type of the binary because it may have been cross-compiled. We fix this by heuristically determining whether paths are UNIX-style or DOS-style by looking for a drive letter or UNC path. If we see a DOS-style path, we use appropriate logic for determining whether the path is absolute and for joining two paths. This is helped by the fact that we should basically always be starting with an absolute path. However, it could mistake a relative UNIX-style path that begins with a directory like "C:" for an absolute DOS-style path. There doesn't seem to be any way around this. Fixes #19784. Change-Id: Ie13b546d2f1dcd8b02e668583a627b571b281588 Reviewed-on: https://go-review.googlesource.com/44017 Run-TryBot: Austin Clements TryBot-Result: Gobot Gobot Reviewed-by: Ian Lance Taylor Reviewed-by: Alex Brainman

debug/dwarf: add Reader.SeekPC and Data.Ranges

2016-03-22T14:06:09Z

These new methods help find the compilation unit to pass to the LineReader method in order to find the line information for a PC. The Ranges method also helps identify the specific function for a PC, needed to determine the function name. This uses the .debug.ranges section if necessary, and changes the object file format packages to pass in the section contents if available. Change-Id: I5ebc3d27faaf1a126ffb17a1e6027efdf64af836 Reviewed-on: https://go-review.googlesource.com/20769 Reviewed-by: Austin Clements Run-TryBot: Ian Lance Taylor TryBot-Result: Gobot Gobot