delta/go-git.git/src/debug/dwarf, branch dev.link

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

2020-10-24T04:11:41+00:00

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: speed up SkipChildren for compilation units

2020-09-21T20:14:27+00:00

For a common pattern of iterating only over top-level compilation units (CU)
Reader.SkipChildren has decode and meterialize all CU subentries just
to skip them, because DW_TAG_compile_unit does not have DW_AT_sibling.
However, CUs have total size encoded before the unit and we already parse them
and know all unit sizes.
Optimize Reader.SkipChildren to use that size when skipping CUs children.

This speeds up iteration over a 1.3GB object file from 7.5s to 0.73s.

Change-Id: I2a8f00955159b4bd13571409f4817805f934cb69
Reviewed-on: https://go-review.googlesource.com/c/go/+/256217
Run-TryBot: Dmitry Vyukov 
TryBot-Result: Go Bot 
Reviewed-by: Than McIntosh 
Reviewed-by: Ian Lance Taylor 
Trust: Than McIntosh

debug/dwarf: call strings.EqualFold instead of calling Lower twice

2019-10-26T02:36:26+00:00

Change-Id: I8dcb425c37a067277549ba3bda6a21206459890a
GitHub-Last-Rev: dc51b9b425ca51cd0a4ac494d4c7a3c0e2306951
GitHub-Pull-Request: golang/go#35132
Reviewed-on: https://go-review.googlesource.com/c/go/+/203097
Run-TryBot: Ian Lance Taylor 
TryBot-Result: Gobot Gobot 
Reviewed-by: Ian Lance Taylor

debug/dwarf: optimize buf.string

2019-09-20T08:55:30+00:00

(*buf).string previously manually searched
through its underlying byte slice until we
encountered a '0'. This change instead uses
bytes.IndexByte that results in a speed up:

$ benchstat before.txt after.txt

name         old time/op    new time/op    delta
BufString-8     257ns ± 1%     174ns ± 1%  -32.37%  (p=0.000 n=9+8)

name         old speed      new speed      delta
BufString-8   495MB/s ± 1%   732MB/s ± 1%  +47.76%  (p=0.000 n=10+8)

name         old alloc/op   new alloc/op   delta
BufString-8      162B ± 0%      162B ± 0%     ~     (all equal)

name         old allocs/op  new allocs/op  delta
BufString-8      3.00 ± 0%      3.00 ± 0%     ~     (all equal)

Change-Id: I7cf241742cc091d5d30d987a168b02d83955b1cf
Reviewed-on: https://go-review.googlesource.com/c/go/+/196657
Run-TryBot: Emmanuel Odeke 
TryBot-Result: Gobot Gobot 
Reviewed-by: Tobias Klauser

debug/dwarf: expose file name table from line table reader

2019-09-18T19:09:02+00:00

Currently, the line table reader keeps the file name table internal.
However, there are various attributes like AttrDeclFile and
AttrCallFile whose value is an index into this table. Hence, in order
to interpret these attributes, we need access to the file name table.

This CL adds a method to LineReader that exposes the file table of the
current compilation unit in order to allow consumers to interpret
attributes that index into this table.

Change-Id: I6b64b815f23b3b0695036ddabe1a67c3954867dd
Reviewed-on: https://go-review.googlesource.com/c/go/+/192699
Run-TryBot: Austin Clements 
TryBot-Result: Gobot Gobot 
Reviewed-by: Than McIntosh 
Reviewed-by: Ian Lance Taylor

debug/dwarf: expose CU byte order

2019-09-18T19:08:45+00:00

Currently, dwarf.Reader exposes the current compilation unit's address
size, but doesn't expose its byte order. Both are important for
decoding many attributes. For example, location descriptions include
addresses that are encoded in native form for the CU.

This CL exposes the byte order of the compilation unit in the same way
we already expose its address size, which makes it possible to decode
attributes containing native addresses.

Change-Id: I92f156818fe92b049d1dfc1613816bb1689cfadf
Reviewed-on: https://go-review.googlesource.com/c/go/+/192698
Run-TryBot: Austin Clements 
TryBot-Result: Gobot Gobot 
Reviewed-by: Ian Lance Taylor

src: gofmt -s

2019-09-09T18:57:05+00:00

Change-Id: I56d7eeaf777ac30886ee77428ca1ac72b77fbf7d
Reviewed-on: https://go-review.googlesource.com/c/go/+/193849
Run-TryBot: Dave Cheney 
TryBot-Result: Gobot Gobot 
Reviewed-by: Brad Fitzpatrick

debug/dwarf: better handling for DW_FORM_indirect

2019-09-03T18:35:32+00:00

Fix a buglet in abbrev processing related to DW_FORM_indirect. When
reading an abbrev entry if we encounter an attribute with form
DW_FORM_indirect, leave the class as ClassUnknown, then when the
abbrev is walked during the reading of the DIE fill in the class based
on the value read at that point (code for handling DW_FORM_indirect
seems to be already partially in place in the DIE reader).

Updates #33488.

Change-Id: I9dc89abf5cc8d7ea96824c0011bef979de0540bf
Reviewed-on: https://go-review.googlesource.com/c/go/+/190158
Run-TryBot: Than McIntosh 
TryBot-Result: Gobot Gobot 
Reviewed-by: David Chase

debug/dwarf, debug/elf: support DWARF 5

2019-09-03T17:37:24+00:00

Change-Id: I6e9d47865c198299d497911c58235cd40f775e34
Reviewed-on: https://go-review.googlesource.com/c/go/+/175138
Run-TryBot: Ian Lance Taylor 
TryBot-Result: Gobot Gobot 
Reviewed-by: Than McIntosh

debug/dwarf: add new constants defined in DWARF 5

2019-09-03T17:32:37+00:00

Also add a few other missing constants.

Also rerun current version of stringer.

Change-Id: I004ef27f6b40fe2cab64c52d169255dfea43fa01
Reviewed-on: https://go-review.googlesource.com/c/go/+/175137
Run-TryBot: Ian Lance Taylor 
TryBot-Result: Gobot Gobot 
Reviewed-by: Austin Clements