debugger stops in assembler code file

[XSven]

What did you do? (required: The issue will be closed when not provided)

I have opened a golang source code file. The package is main. I am at a statement line. I am starting the debugger using

GoDebugStart . -url=http://somewhere -n=10 -c=20

The arguments that I have passed are application specific and should not matter. A breakpoint seems to be automatically created at the start of the debugger. I am pressing <F5> (:GoDebugContinue).

What did you expect to happen?

The debugger stops at the given breakpoint.

What happened instead?

When pressing <F5> (:GoDebugContinue) the debugger stops in the file /usr/lib/golang/src/runtime/rt0_linux_amd64.s

This is the vim-go debug output

"main.go" 40L, 641B
vim-go: job command: ['/home/sven.willenbuecher/go/bin/gopls', '-remote=auto']
vim-go: shell command: '/usr/bin/go' 'env' 'GOMOD'
vim-go: shell command: '/usr/bin/go' 'env' 'GOMOD'
vim-go: initializing gopls
vim-go: initialized gopls
vim-go: Finished loading packages.
vim-go: shell command: '/usr/bin/go' 'list'
vim-go: [debug] dispatched
vim-go: job command: ['/home/sven.willenbuecher/go/bin/dlv', 'debug', 'github.com/XSven/hit_project/cmd/hit', '--output', '/tmp/vSahZ1J/8', '--headless', '--api-version', '2', '--listen', '127.0.0.1:8181', '--log', '--log-output', 'debugger,rpc', '--', '-url=http://somewhere', '-n=10', '-c=20']
vim-go: sending to dlv RPCServer.Command
vim-go: sending to dlv RPCServer.ListBreakpoints
vim-go: sending to dlv RPCServer.CreateBreakpoint
vim-go: sending to dlv RPCServer.Command
vim-go: sending to dlv RPCServer.ListBreakpoints
vim-go: sending to dlv RPCServer.LastModified
vim-go: sending to dlv RPCServer.State
vim-go: sending to dlv RPCServer.Stacktrace
vim-go: sending to dlv RPCServer.ListLocalVars
vim-go: sending to dlv RPCServer.ListFunctionArgs
vim-go: sending to dlv RPCServer.ListRegisters
vim-go: current goroutine not found...
vim-go: sending to dlv RPCServer.ListGoroutines
vim-go: No Goroutines Running Now...

Configuration (MUST fill this out):

vim-go version:

1401b57 - 2023-10-02 11:13:19 -0700 (HEAD -> master, origin/master, origin/HEAD) update CHANGELOG.md for #3587 (Billie Cleek <bhcleek@gmail.com>)

vimrc you used to reproduce:

vimrc

Vim version (first three lines from :version):

VIM - Vi IMproved 8.2 (2019 Dec 12, compiled Feb 09 2023 00:00:00)
Included patches: 1-2637
Modified by bugzilla@redhat.com

Go version (go version):

go version go1.20.6 linux/amd64

Go environment

go env Output:

GO111MODULE=""
GOARCH="amd64"
GOBIN="/home/sven.willenbuecher/go/bin"
GOCACHE="/home/sven.willenbuecher/.cache/go-build"
GOENV="/home/sven.willenbuecher/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/sven.willenbuecher/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/sven.willenbuecher/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/lib/golang"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/lib/golang/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="go1.20.6"
GCCGO="gccgo"
GOAMD64="v1"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/sven.willenbuecher/go/src/github.com/XSven/hit_project/go.mod"
GOWORK=""
CGO_CFLAGS="-O2 -g"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-O2 -g"
CGO_FFLAGS="-O2 -g"
CGO_LDFLAGS="-O2 -g"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build3323771479=/tmp/go-build -gno-record-gcc-switches"

gopls version

gopls version Output:

golang.org/x/tools/gopls v0.14.2
    golang.org/x/tools/gopls@v0.14.2 h1:sIw6vjZiuQ9S7s0auUUkHlWgsCkKZFWDHmrge8LYsnc=

[bhcleek]

Is your application an http server that's waiting for a request?

[XSven]

No it is a experiment that teaches me how to use the flag package to parse command-line options and how to coerce strings into other types. This is very basic stuff and no tricky networking.

[bhcleek]

What line is the breakpoint being created on? Can you give me more explicit replication steps?

[XSven]

I have opened the main.go file and went to line 30. Then I have started the debugger. This already creates the breakpoint at line 30. Then I have pressed <F5>

    1 package main
    2
    3 import (
    4         "fmt"
    5         "os"
    6         "runtime"
    7 )
    8
    9 const (
   10         bannerText = `
   11 __ __ __ ______
   12 /\ \_\ \ /\ \ /\__ _\
   13 \ \ __ \ \ \ \ \/_/\ \/
   14  \ \_\ \_\ \ \_\ \ \_\
   15  \/_/\/_/ \/_/ \/_/
   16 `
   17         usageText = `
   18 Usage:
   19 -url
   20  HTTP server URL to make requests (required)
   21 -n
   22  Number of requests to make
   23 -c
   24  Concurrency level`
   25 )
   26
   27 func banner() string { return bannerText[1:] }
   28 func usage() string  { return usageText[1:] }
   29 func main() {
>  30         f := &flags{
   31                 n: 100,
   32                 c: runtime.NumCPU(),
   33         }
   34         if err := f.parse(); err != nil {
   35                 os.Exit(1)
   36         }
   37         fmt.Println(banner())
   38         fmt.Printf("Making %d requests to %s with a concurrency level of %d.\n",
   39                 f.n, f.url, f.c)
   40 }

[bhcleek]

I'm not able to duplicate the behavior you're seeing, but that could be because I'm using a mac. Can you try again after :GoUpdateBinaries dlv?

What breakpoint are you expecting it to break on? You're already on line 30 and said there was a breakpoint there and it breaks on that. Is your concern that it's breaking after that?

The behavior you're seeing where it breaks in rt0_linux_amd64.s seems like it's yielding to the OS. Can you try :GoDebugContinue instead of using <F5>? I'm wondering if your <F5> is somehow bound to :GoDebugStep or :GoDebugNext.

I'm also interested to know what happens if you :GoDebugNext through each line - on which line does the :GoDebugNext cause the debugger to break in rt0_linux_amd64.s?

Also, can you put a breakpoint on line 34? It's ok to still have the first breakpoint at line 30. If that works, then let's try making the breakpoint on line 34 the only breakpoint.

[XSven]

• Updating dlv has changed nothing. It was already the latest one.
• There was already a breakpoint at line 30 because that was the cursor position when I have started the debugger. I don't know if this is an on purpose of by accident behaviour?!
• I have used :GoDebugContinue instead of <F5>, the strange behaviour was the same.
• Amazingly :GoDebugNext is unknown: E492: Not an editor command: GoDebugNext
• To create an additional breakpoint at line 34 using <F9> was possible, but nothing else has changed: <F5> yields to the OS and :GoDebugNext is still unknown.

By the way my oS is CentOS9-stream and I am running this in a WSL context.

[bhcleek]

Can you debug successfully with the delve CLI?

[XSven]

I don't know how this works, but I was able to debug successfully using VSCode using the standard Go extension that as far as I know uses delve too. By the way the vim-go debug output that I have provided initially does not tell you anything, correct?

[bhcleek]

By the way the vim-go debug output that I have provided initially does not tell you anything, correct?

That's right. It's useful, but doesn't pinpoint the problem.