If the last entry of the package path contains a '.' the corresponding
DIEs for its types will replace the '.' character with '%2e'. We must
do the same when resolving the package path of the concrete type of an
interface variable.

Fixes #1137

Fixes a bug where the 'go' statement that created a goroutine was
incorrectly reported.

Fixes #1135

Previously the file handle for the newly created default config was
being closed and thrown away as opposed to returned to the caller to
finish setting up config for the rest of the process. This patch changes
to return a handle to the newly created config so setup can happen as
normal. This fixes a bug where Delve can crash on first run when a
config is not present on the system.

Fixes #1129

Add new version to CHANGELOG and update internal version.

debug_info entries can use DW_AT_abstract_origin to inherit the
attributes of another entry, supporting this attribute is necessary to
support DW_TAG_inlined_subroutine.

Go, starting with 1.10, emits DW_TAG_inlined_subroutine entries when
inlining is enabled.

* Handle race between fork and task_for_pid

On macOS a call to fork and a subsequent call to task_for_pid will race each other. This is because the macOS kernel assigns a new proc_t structure early but the new task, thread and uthread come much later. The function exec_mach_imgact in the XNU sources contains this logic.

In a system under load or one with delays in fork processing (i.e. various security software), task_for_pid as currently called by Delve often returns the parent task. This can be seen by printing out the task number around line 86. In a normal system we would see three calls:

-> ~/go/bin/dlv --listen=localhost:59115 --headless=true --api-version=2 --backend=native exec ./___main_go -- 
Task: 9731
Task: 9731
Task: 9731
API server listening at: 127.0.0.1:59115

This is the result on a system where the race is lost:

-> ~/go/bin/dlv --listen=localhost:59115 --headless=true --api-version=2 --backend=native exec ./___main_go -- 
Task: 8707
Task: 10499
Task: 10499
could not launch process: could not get thread count

In this latter case, task 8707 is the parent task. The child task of 10499 was desired and hence the error.

This code change checks to make sure the returned task is not that of the parent. If it is, it retries. It's possible other macOS reported Delve issues are the result of this failed race.

* proc: correct formatting

Our current frame caching strategy doesn't handle extended locations
expressions correctly, disable it on variables that don't have a simple
address.

Fixes #1088

Fixes #1090

Document how to pass flags to the cli program being debugged.

* core_test: fix TestCoreFpRegisters on go1.9

It was broken by 7bec20e5

* travis-ci: switch to VM builders for linux

Much like the bug in issue #1031 and commit
f6f6f0bf pointers can also escape to
the heap and then have a zero address (and no children) when we
autodereference.

1. Mark autodereferenced escaped variables with a 0 address as
   unreadable.
2. Add guards to the pretty printers for unsafe.Pointer and pointers.

Fixes #1075

Depending on how the runtime schedules our goroutines we can get
unlucky and have the first call to runtime.newstack we intercept be for
a different goroutine (usually the garbage collector).
Only check stacktraces that happen on the same goroutine that executed
main.main.

Help out those of us habituated to pdb. <:^)

https://docs.python.org/3/library/pdb.html

* command/terminal: allow restart to change process args

Add -args flag to "restart" command. For example, "restart -args a b c" will
pass args a b c to the new process.

Add "-c" flag to pass the checkpoint name. This is needed to disambiguate the
checkpoint name and arglist.

Reverted unnecessary changes.

* Applied reviewer comments.

Vendored argv.

Change the syntax of restart. When the target is is in recording mode, it always
interprets the args as a checkpoint. Otherwise, it interprets the args as
commandline args. The flag "-args" is still there, to handle the case in which
the user wants to pass an empty args on restart.

* Add restartargs.go.

Change "restart -args" to "restart -noargs" to clarify that this flag is used to
start a process with an empty arg.

The runtime calls into g0 in many places, not necessarily using
runtime.systemstack or runtime.asmcgocall.
One example of this is the call to runtime.newstack inside
runtime.morestack.

If we stop the process while one goroutine is executing
runtime.newstack we would be unable to fully scan its stack because we
don't know that we have to switch back to the goroutine stack after
runtime.newstack.

Instead of tracking down every possible way that the runtime switches
to g0 we switch to the goroutine stack immediately after the top of the
stack, unless cgo is being executed on the systemstack.

Fixes #1066

The rr backend doesn't report the exit status (the argument of the W
packet seems to always be 0).

Fixes #1067

Improve the link ordering for the main README and add a
"Getting Started" doc with basic usage information for new users.

I saw a test failure related to this in Travis-CI, if it happens again
I would like to know what's causing it.

Fixes #1052

Adds a configuration option (show-location-expr) that when activated
will cause the whatis command to also print the DWARF location
expression for a variable.

As of Go 1.8, allows empty GOPATH environment variable.

Sometimes delve on Appveyor can't remove the built binary before
exiting and gets an "Access is denied" error when trying.
See: https://ci.appveyor.com/project/derekparker/delve/build/1527

The last entry of the debug_line table is supposed to be valid for
every PC address greater than its address.

So far we have evaluated the locspec "+0" the same way we evaluate all
"+n" locspecs, this means that we turn the current PC into a file:line
pair, then we turn back the file:line into a PC address.

Normally this is harmless, however all autogenerated code returns the
source position "<autogenerated>:1" which resolves back to the very
first autogenerated instruction in the code.

This messes up the behaviour of the "disassemble" command which uses
the locspec "+0" to figure out what code to disassemble if no arguments
are passed.

We should make +0 always resolve to the current PC (of the given scope)
so that clients can use +0 as a default locspec.

Go 1.10 new method of caching packages means that there is no need to
specify 1.10.