Commit Graph

10 Commits

Author SHA1 Message Date
Alessandro Arzilli
1a75095286 godwarf: fix nil pointer reading recursive types involving an array (#1582)
Fixes #1578
2019-06-12 17:35:00 -07:00
Alessandro Arzilli
f3b149bda7 proc: support debugging plugins (#1414)
This change splits the BinaryInfo object into a slice of Image objects
containing information about the base executable and each loaded shared
library (note: go plugins are shared libraries).

Delve backens are supposed to call BinaryInfo.AddImage whenever they
detect that a new shared library has been loaded.

Member fields of BinaryInfo that are used to speed up access to dwarf
(Functions, packageVars, consts, etc...) remain part of BinaryInfo and
are updated to reference the correct image object. This simplifies this
change.

This approach has a few shortcomings:

1. Multiple shared libraries can define functions or globals with the
   same name and we have no way to disambiguate between them.

2. We don't have a way to handle library unloading.

Both of those affect C shared libraries much more than they affect go
plugins. Go plugins can't be unloaded at all and a lot of name
collisions are prevented by import paths.

There's only one problem that is concerning: if two plugins both import
the same package they will end up with multiple definition for the same
function.
For example if two plugins use fmt.Printf the final in-memory image
(and therefore our BinaryInfo object) will end up with two copies of
fmt.Printf at different memory addresses. If a user types
  break fmt.Printf
a breakpoint should be created at *both* locations.
Allowing this is a relatively complex change that should be done in a
different PR than this.

For this reason I consider this approach an acceptable and sustainable
stopgap.

Updates #865
2019-05-08 14:06:38 -07:00
aarzilli
7e86d6749f dwarf/godwarf: tolerate cyclical type DIEs
As specified in line dwarf/godwarf/type.go:507 the typeCache entry
should always be set before recursive calls to readType to avoid infite
recursion.
Most code in readType already does this but some of the code added
later to handle Go types was wrong.
Fix this bug and also fix the String and Size methods of Type so that
they handle recursive types "correctly" (i.e. they don't recur
forever).

No test is added for this since all legitimate uses of cyclical types
were already handled correctly and the malformed types emitted by the
go compiler will probably be removed in 1.12.
See: https://github.com/golang/go/issues/29264

Fixes #1444
2019-01-04 14:52:28 -08:00
Derek Parker
4c9a72e486 *: Update import name to github.com/go-delve/delve
The repository is being switched from the personal account
github.com/derekparker/delve to the organization account
github.com/go-delve/delve. This patch updates imports and docs, while
preserving things which should not be changed such as my name in the
CHANGELOG and in TODO comments.
2019-01-04 19:43:13 +01:00
aarzilli
d2904322fa proc: add flag to disable escape checking in function calls
Fix escape checking in function calls  and add a flag to disable it.
2018-10-15 09:31:35 -07:00
aarzilli
12a3f8bb97 proc: change (*Variable).setValue for use in CallFunction
Changes (*Variable).setValue so that it can be used in CallFunction to
set up the argument frame for the function call, adding the ability to:
- nil nillable types
- set strings to the empty string
- copy from one structure to another (including strings and slices)
- convert any interface type to interface{}
- convert pointer shaped types (map, chan, pointers, and structs
  consisting of a single pointer field) to interface{}

This covers all cases where an assignment statement can be evaluated
without allocating memory or calling functions in the target process.
2018-08-15 10:29:16 -07:00
aarzilli
440b440562 proc: support GNU compressed debug sections (go1.11 support)
Go1.11 switched to the zlib-gnu compression format for debug sections.
Change proc and and a test in dwarf/line to support this change.

Also deletes some dead code from pkg/proc/bininfo.go that hadn't been
used in a long time.
2018-06-22 11:20:38 -07:00
aarzilli
8bbccb3e66 proc: use new extended attribute to resolve concrete type of interfaces
go1.11 adds a new extended attribute to all type DIEs containing the
address of the corresponding runtime._type struct, use this attribute
to find the DIE of the concrete type of interface variables when
available.
2018-06-11 11:09:02 -07:00
aarzilli
f098915192 proc/tests: testing apparatus for complex location expressions 2017-11-21 11:51:02 -08:00
aarzilli
1e3ff49610 pkg/dwarf/godwarf: split out type parsing from x/debug/dwarf
Splits out type parsing and go-specific Type hierarchy from
x/debug/dwarf, replace x/debug/dwarf with debug/dwarf everywhere,
remove x/debug/dwarf from vendoring.
2017-08-01 11:20:25 -06:00