Add documentation on how to pass arguments to the program generated by
`dlv test`.

Fixes #2458

Check for errors, log them and return early, do not try to allocate
large chunks of memory that we can never possibly read from the file.

Fixes #2449

* go.mod: update google/go-dap to 0.5.0

* Go mod tidy
Co-authored-by: NPolina Sokolova <polinasok@users.noreply.github.com>

* proc: Slightly better version check for gdb server on newer macOS

* Adjusted version to be >= 1200 and <= 1205

The documentation mentions flags that do not exist. Replace them with
the existing, --log-dest flag.

Moves the implementation of Registers.Get out of the backends and into
proc where it can be implemented only once per architecture.

* examinememory: evaluate addr as expression

This makes it easy to read memory locations at an offset of a known
address, e.g.:

x 0xc000046800 + 32

* use feedback from @aarzilli

- expression mode is now enabled via -x flag
- support "-x var", "-x &var" in addition to "-x <addr expr>"
- some refactoring

* add test cases

* deal with double spaces

* update docs

* add new failing test

* fix docs

* simplify implementation, update test & docs

* Fix docs

* service/dap: add go build stderr to error response

* service/dap: add go build stderr to error response

* Skip message check for build errors

* test for flag provided message

Due to variable shadowing the SwitchGoroutine command never failed.

There seems to be a problem where debugserver will leave a zombie
process instead of detaching correctly, we are sending the right
commands, it doesn't seem to be a problem with Delve.

* service/dap: refine teardown logic

* Address review comments + add missing lock/unlock

* Narrow lock scope

* Update comments only

* Remove redundan temp var from stopNoDebugProcess

* Clarify comment

* Set debugger to nil after detach to prevent dup teardown in Stop()
Co-authored-by: NPolina Sokolova <polinasok@users.noreply.github.com>

Rename the launch configuration for specifying the working directory.

* service/dap: annotate shadowed variable names in variables request

In order to distinguish variables that are shadowed, this change
updates the names from 'name' to '(name)'. This is the same syntax
used in the terminal package.

* remove unnecessary comment

* Add todo for evaluate name

* Check the evaluateName result is the unshadowed var

* service/rpcommon: resolve race between Detach and shutdown

Detach will close DisconnectChan causing the server to initiate
shutdown, there is a race between Detach writing its response to the
client and the shutdown terminating the server process.
If Detach loses the race the response to the Detach request is never
sent to the client and the client will report an EOF error instead.

This change delays the start of the shutdown process until after Detach
has written its response.

Fixes an occasional failure of TestContinue.

* service/rpccommon: ignore listener error when shutting down

Ignore the closed listener error when the server is being shut down in
response to a SIGINT signal.

Fixes #1633

* service/dap: add substitutePath configuration

Similar to substitute-path configuration in the dlv cli, substitutePath
in dap allows users to specify path mappings that are applied to the
source files in stacktrace and breakpoint requests.

Updates #2203

* service/dap: refactor the startup of the fixture for attach

Add a helper function for starting up a process to attach to.

* service/dap: update substitute path tests for windows

* service/dap: remove lines that should have been removed in merge

* respond to comments on pr

* move logging to helper functions

* make test comments more clear

* Add comments about absolute paths

* fix log messages

* clarify test comments

* remove comment about absolute paths

Co-authored-by: NPolina Sokolova <polinasok@users.noreply.github.com>

We have some places where we use proc.ErrProcessExited and some places
that use &proc.ErrProcessExited, resulting in checks for process exited
errors occasionally failing on some architectures.
Uniform use of ErrProcessExited to the non-pointer version.

Fixes intermittent failure of TestStepOutPreservesGoroutine.

Co-authored-by: NPolina Sokolova <polinasok@users.noreply.github.com>

When restarting we must take care of setting breakpoint IDs correctly
so that enabled breakpoints do not end up having the same ID as a
disabled breakpoint, also we must make sure that breakpoints created
after restart will not get an ID already used by a disabled breakpoint.

Delete tests for old versions of Go that are no longer run, remove skip
from tests that seemingly work.

Co-authored-by: NPolina Sokolova <polinasok@users.noreply.github.com>

It's expected that users enter invalid expressions through DEBUG
CONSOLE. Pop up for every error is not pleasant.

Co-authored-by: NPolina Sokolova <polinasok@users.noreply.github.com>

- allow a concrete subprogram to be treated as the abstract origin for an inlined call
- allow nameless concrete and abstract subprograms

Fixes #2393

* dap: change how noDebug launch request is served

PR #2400 added support for noDebug launch requests - that was done
by directly starting the target program using os/exec.Cmd and blocking
the launch request indefinitely until the program terminates or
is stopped with a disconnect request (when dlv dap can support it).
Even though the approach seemed to work for user, that adds an extra
control flow and complexity to the codebase.

This change takes a different approach to implement the noDebug
launch feature. Instead of using os/exec.Cmd, this uses the existing
debug launch path, but avoids setting breakpoints. Finally, the program
will start upon receiving onConfigurationDoneRequest and blocks there
until the program terminates. This simplifies the code.

The DAP spec does not explicitly specify what to do about other
requests. It seems like VSCode can issue evaluate requests or other
requests after the configuration done request. Currently they are
blocked because the program is in running state. We can consider checking
s.noDebug and responding with an error in the future if we want/need to.

See the log below for a typical DAP request/response sequence:

2021-03-29T01:42:53-04:00 debug layer=dap building binary at /Users/hakim/projects/s/__debug_bin
2021-03-29T01:42:55-04:00 info layer=debugger launching process with args: [/Users/hakim/projects/s/__debug_bin]
2021-03-29T01:42:55-04:00 debug layer=dap [-> to client]{"seq":0,"type":"event","event":"initialized"}
2021-03-29T01:42:55-04:00 debug layer=dap [-> to client]{"seq":0,"type":"response","request_seq":2,"success":true,"command":"launch"}
2021-03-29T01:42:55-04:00 debug layer=dap [<- from client]{"seq":3,"type":"request","command":"setBreakpoints","arguments":{"source":{"name":"main.go","path":"/Users/hakim/projects/s/main.go"},"breakpoints":[{"line":9}],"lines":[9]}}
2021-03-29T01:42:55-04:00 error layer=dap Unable to set or clear breakpoints: running in noDebug mode
2021-03-29T01:42:55-04:00 debug layer=dap [-> to client]{"seq":0,"type":"response","request_seq":3,"success":false,"command":"setBreakpoints","message":"Unable to set or clear breakpoints","body":{"error":{"id":2002,"format":"Unable to set or clear breakpoints: running in noDebug mode"}}}
2021-03-29T01:42:55-04:00 debug layer=dap [<- from client]{"seq":4,"type":"request","command":"configurationDone","arguments":{}}
2021-03-29T01:42:55-04:00 debug layer=dap [-> to client]{"seq":0,"type":"response","request_seq":4,"success":true,"command":"configurationDone"}
2021-03-29T01:42:55-04:00 debug layer=debugger continuing
Hello
2021-03-29T01:43:00-04:00 debug layer=dap [-> to client]{"seq":0,"type":"event","event":"terminated","body":{}}
2021-03-29T01:43:00-04:00 debug layer=dap [<- from client]{"seq":5,"type":"request","command":"threads"}
2021-03-29T01:43:00-04:00 debug layer=dap [-> to client]{"seq":0,"type":"response","request_seq":5,"success":true,"command":"threads","body":{"threads":null}}
2021-03-29T01:43:00-04:00 debug layer=dap [<- from client]{"seq":6,"type":"request","command":"disconnect","arguments":{}}
2021-03-29T01:43:00-04:00 debug layer=dap [-> to client]{"seq":0,"type":"response","request_seq":6,"success":true,"command":"disconnect"}
2021-03-29T01:43:00-04:00 debug layer=debugger halting
2021-03-29T01:43:00-04:00 error layer=dap Process 27219 has exited with status 0
2021-03-29T01:43:00-04:00 debug layer=debugger detaching

Updates https://github.com/golang/vscode-go/issues/1111

* service/dap: address polina's comments for noDebug logic

Reworked so the noDebug launch request again blocks launch request
handler after responding with the launch response. By skipping
the initialized event, it should prevent well-behaving clients from
sending any further requests. Currently, doesn't matter because
the handler goroutine will be blocked until the program termination
anyway.

Placed mutex back, since I noticed that's the only way to prevent
racing between Stop and the handler goroutine. The synchronization
lotic (in particular, during teardown) should be revisited after
asynchronous request support work is done.

* dap: address more comments

Remove unnecessary conditionally compiled files introduced with the
darwin/arm64 port.

Some users seem to need to do this in order to use a debugger.

* service/dap: switch goroutine before stepping

The correct goroutine needs to be selected when stepping in order
for the step to execute to the correct location.

* handle next in progress while stepping

* Add tests for steps when switching goroutine

* remove nextInProgress handling

* add new step out test and review debug state check

* update text of stopped event and set goroutine id

Error level logging shows up in the users' consoles/terminals
so be more conservative when logging. Move the followings to
Debug logging.

- DAP error reponses caused by invalid requests.
They are application level errors and DAP clients should handle them.
- Errors reported when debugee already exited.

Fixes golang/vscode-go#1392

Changes print so a format argument can be specified by using '%' as
prefix. For example:

    print %x d

will print variable 'd' in hexadecimal. The interpretarion of the
format argument is the same as that of fmt's package.

Fixes #1038
Fixes #1800
Fixes #2159

* Truncate long compound map keys and use address suffix only for those

* Remove test typo that causes failures
Co-authored-by: NPolina Sokolova <polinasok@users.noreply.github.com>

* Add logging and comments to clarify relative output path treatement

* Use absolute output path in one of the unittests
Co-authored-by: NPolina Sokolova <polinasok@users.noreply.github.com>

If the launch requests has noDebug attribute set, run the built
binary directly. The launch request handler will block until
the binary terminates, so the editor won't send additional requests
like breakpoint setting etc. Still disconnect or restart requests
can flow in though and they should trigger killing of the target
process if it's still running.

In order to run the binary using os/exec on windows, the target
binary has to have .exe as its extension. So, add .exe to the default
output name if it is on windows. I am not sure though yet we want
to modify the user-specified output or not yet. Considering how
go commands behave (not automatically append .exe for 'go build -o')
I think respecting what user specified is right, but the failure
(file not exist) may be mysterious.

* service/dap: use specified working directory for launch requests

If a user specifies a working directory in the launch request,
then the process should use that working directory. This may
affect how the program runs and the user should be able to have
control over this.

* service/dap: add tests for launch with working dir

Added tests to make sure the working directory is set correctly.

* service/dap: fix TestWorkingDir on windows

* service/dap: use %q to print quoted string

* cmd/dlv: update dap warning about working dir

* service/dap: change the launch argument to be wd`

* update warning to specify only launch request