gdb: No struct type named runtime.rtype

[andredasilvapinto]

I'm having an error while trying to manually load runtime-gdb.py on GDB.

go1.4 linux/amd64
gdb 7.8
Ubuntu 14.04.1 LTS

gdb ./collect-jmx.test -d $GOROOT
...
(gdb) source /usr/local/go/src/runtime/runtime-gdb.py 
Loading Go Runtime support.
Traceback (most recent call last):
  File "/usr/local/go/src/runtime/runtime-gdb.py", line 205, in <module>
    _rctp_type = gdb.lookup_type("struct runtime.rtype").pointer()
gdb.error: No struct type named runtime.rtype.

[pnasrat]

Replicated using https://github.com/golang/example/tree/master/stringutil

go test -c .

Using GDB:

gdb -q ./stringutil.test
Reading symbols from ./stringutil.test...done.
(gdb) source /usr/src/go/src/runtime/runtime-gdb.py
Loading Go Runtime support.
Traceback (most recent call last):
  File "/usr/src/go/src/runtime/runtime-gdb.py", line 205, in <module>
    _rctp_type = gdb.lookup_type("struct runtime.rtype").pointer()
gdb.error: No struct type named runtime.rtype.
(gdb) set pagination off
(gdb) set logging on
Copying output to gdb.txt.
(gdb) info types
# much output
(gdb) quit

Examining the types we see

grep runtime gdb.txt   | grep type;

struct []*runtime._type;
typedef struct runtime.iface error;
typedef struct runtime.iface flag.Value;
typedef struct runtime.iface flag.boolFlag;
typedef struct runtime.iface fmt.Formatter;
typedef struct runtime.iface fmt.GoStringer;
typedef struct runtime.iface fmt.Scanner;
typedef struct runtime.iface fmt.Stringer;
typedef struct runtime.iface fmt.runeUnreader;
typedef void (struct runtime.g *) func(*runtime.g);
typedef void (struct runtime.stkframe *, void *, bool *) func(*runtime.stkframe, unsafe.Pointer) bool;
typedef void (struct []runtime.StackRecord, int *, bool *) func([]runtime.StackRecord) (int, bool);
typedef struct runtime.iface interface { runtime.f() };
typedef struct runtime.eface interface {};
typedef struct runtime.iface io.Reader;
typedef struct runtime.iface io.ReaderFrom;
typedef struct runtime.iface io.RuneReader;
typedef struct runtime.iface io.Writer;
typedef struct runtime.iface io.WriterTo;
typedef struct hash<string,*runtime/pprof.Profile> * map[string]*runtime/pprof.Profile;
typedef struct runtime.iface os.FileInfo;
typedef struct runtime.iface os.Signal;
typedef struct runtime.iface reflect.Type;
typedef struct runtime.iface regexp.input;
struct runtime._type;
typedef runtime.bucketType;
struct runtime.chantype;
typedef struct runtime.iface runtime.fInterface;
struct runtime.functype;
struct runtime.interfacetype;
typedef runtime.intptr;
struct runtime.maptype;
typedef runtime.pageID;
struct runtime.ptrtype;
struct runtime.slicetype;
typedef struct runtime.iface runtime.stringer;
struct runtime.typeAlg;
typedef runtime.uintreg;
struct runtime.uncommontype;
typedef struct runtime.iface runtime/pprof.countProfile;
typedef struct runtime.iface sort.Interface;
typedef struct runtime.iface sync.Locker;

[pnasrat]

Looking at the dist source http://golang.org/src/runtime/type.h versus https://github.com/golang/go/blob/master/src/reflect/type.go

It kind of works (there seems to be some issue still) if I change runtime-gdb.py to lookup reflect.rtype. I can set a breakpoint and list and use next.

(gdb) break reverse.go:21
Breakpoint 1 at 0x45a4e0: file /go/src/stringutil/reverse.go, line 21.
Starting program: /go/src/stringutil/stringutil.test



^CPython Exception <class 'KeyboardInterrupt'> Quit:
Breakpoint 1, stringutil.Reverse (s="Hello, world", ~r1=) at /go/src/stringutil/reverse.go:21
21  func Reverse(s string) string {
(gdb) p s
$1 = "Hello, world"

[randall77]

Did you also try runtime._type? That's what runtime.type is now called.

[pnasrat]

@randall77 it's looking for runtime.rtype which was copied from reflect.rtype for gdb not _type

[pnasrat]

Would it be helpful to have some test cases for the python gdb support that could be run?

[ianlancetaylor]

Yes, I think some test cases would be helpful. We couldn't run them in all cases, but perhaps we could run them if a suitable version of gdb was installed.

[pnasrat]

OK I'll take a look at doing this but it may not be until next week.

[hustcat]

+1 When I use gdb to debug docker, and I encountered the same problem.

Linux/CentOS 6.5
golang 1.3
gdb 7.2

[pnasrat]

Change out for review

https://go-review.googlesource.com/#/c/2821/