We occasionally receive bug reports from users of VSCode-go and GoLand.
GoLand has its own way of capturing the packet exchange between itself
and delve but VSCode-go (supposedly) doesn't.
So far this hasn't been a problem since all bug reports were obvious
bugs on the plugin or easy to reproduce without VSCode-go, but it might
be helpful in the future to have a way to log the packet exchange
between dlv and a frontend.
This commit adds a --log-output option to enable logging of all rpc
messages and changes service/rpccommon accordingly.
Displays the return values of the current function when we step out of
it after executing a step, next or stepout command.
Implementation of this feature is tricky: when the function has
returned the return variables are not in scope anymore. Implementing
this feature requires evaluating variables that are out of scope, using
a stack frame that doesn't exist anymore.
We can't calculate the address of these variables when the
next/step/stepout command is initiated either, because between that
point and the time where the stepout breakpoint is actually hit the
goroutine stack could grow and be moved to a different memory address.
Add a new method "Common" to proc.Process that returns a pointer to a
struct that pkg/proc can use to store its things, independently of the
backend.
This is used here to replace the AllGCache typecasts, it will also be
used to store the return values of the stepout breakpoint and the state
for injected function calls.
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.
Go1.11 uses the is_stmt flag of .debug_line to communicate which
assembly instructions are good places for breakpoints, we should
respect this flag.
These changes were introduced by:
* https://go-review.googlesource.com/c/go/+/102435/
Additionally when setting next breakpoints ignore all PC addresses that
belong to the same line as the one currently under at the cursor. This
matches the behavior of gdb and avoids stopping multiple times at the
heading line of a for statement with go1.11.
Change: https://go-review.googlesource.com/c/go/+/110416 adds the
prologue_end flag to the .debug_line section to communicate the end of
the stack-split prologue. We should use it instead of pattern matching
the disassembly when available.
Fixes#550
type of interfaces
'c7cde8b'.
Maps were always loaded with using the default configuration during a
reslice. This is probably a remnant from when we didn't let clients
configure the load parameters.
If dwz binary is available in the system, test delve's ability to find
deduplicated symbols in the DWARF information.
dwzcompression.go contains a small C function (void fortytwo()) which
calls glibc's fprintf with stdin as first argument. Normally, stdin
will be present as a DW_TAG_variable as part of a DW_TAG_compile_unit
named dwzcompression.cgo2.c.
After running dwz on the binary, stdin is moved to a
DW_TAG_partial_unit, which is imported from dwzcompression.cgo2.c with
a DW_TAG_imported_unit.
This test verifies that delve is able to find stdin symbol's type, as a
way to confirm it understands dwz's compressed/deduplicated DWARF
information.
The EnableDWZCompression flag allows tests to request BuildFixture to
run "dwz" on the Fixture's resulting binary to compress/deduplicate its
DWARF sections.
'dwz' is a tool that reduces the size of DWARF sections by
deduplicating symbols. The deduplicated symbols are moved from their
original 'compile unit' to a 'partial unit', which is then referenced
from its original location with an 'imported unit' tag.
In the case of Go binaries, all symbols are located in a single
'compile unit', and the name of each symbol contains a reference to its
package, so 'dwz' is not able to deduplicate them. But still, some C
symbols included in the binary are deduplicated, which also alters the
structure of the DWARF sections, making delve unable to parse them
(crashing in the attempt).
While it would've been possible to simply ignore the C symbols, or
blindly loading all then into BinaryInfo members (packageVars,
Functions...), for correctness sake this change tries to do the right
thing, staging symbols into temporary partialUnit objects, moving them
to BinaryInfo when they are actually requested by a 'imported unit'
tag.
Change the linux verison of proc/native and proc/gdbserial (with
debugserver) so that they let the target process use the terminal when
delve is launched in headless mode.
Windows already worked, proc/gdbserial (with rr) already worked.
I couldn't find a way to make proc/gdbserial (with lldb-server) work.
No tests are added because I can't think of a way to test for
foregroundness of a process.
Fixes#65
Go seems to be generating multiple compilation units that have
the same file. I think this happens for functions that get inlined.
Without this patch, those inlined functions break the ability to set
a breakpoint at other lines in the file. I was able to load the same
binary in gdb and set a breakpoints throughout the file without issue.
```
➜ objdump --dwarf=decodedline automate-gateway | grep handler/users.go
.../handler/users.go:[++]
s/.../handler/users.go 20 0xb6dd88
.../handler/users.go:[++]
s/.../handler/users.go 20 0xb6e50f
.../handler/users.go:[++]
s/automate-gateway/handler/users.go 32 0xb66640
```
Inlined functions are still a little weird. setting a breakpoint on
a function that gets inlined picks the first occurence. That being
said, I think delve should still do something reasonable for the rest
of the lines in the file.
Previously to 4e177bb99acc511897f9cdbfc6cbc50d92ae4725 it was possible
to use --log without arguments to enable logging, this commit reenables
that use case.
The new functionality of the --log flag moved to a new flag name
--logx.
Fixes#1188
Caching the frame in variablesByTag is problematic:
1. accounting for variables that are (partially) stored in registers is
complicated (see issue #1106)
2. for some types (strings, interfaces...) simply creating the Variable
object reads memory, which therefore happens before we can do any
caching.
Instead cache the entire frame when the EvalScope object is created.
The cached range is between the SP value of the current frame and the
CFA of the preceeding frame, if available, or the CFA of the current
frame otherwise.
Fixes#1106
Change memCache so that the preloaded memory is not read immediately
but only after the actual read to the preloaded range.
This allows us to request caching the entire stack frame every time we
create an eval scope and no unnecessary reads will be made even if the
user is just trying to evaluate a global variable.
Vet found the following errors:
pkg/proc/moduledata.go:152: namedata[1] (8 bits) too small for shift of 8
pkg/proc/moduledata.go:170: taglendata[0] (8 bits) too small for shift of 8
The fix is to convert before shifting.
I've seen TestFrameEvaluation fail in CI in the past. It's been a while
since the last time and I couldn't reproduce it locally at all. I'd
like to have some instrumentation in case it happens again.
printcontext should use SelectedGoroutine instead of trusting that the
goroutine running on current thread matches the SelectedGoroutine.
When the user switches to a parked goroutine CurrentThread and
SelectedGoroutine will diverge.
Almost all calls to printcontext are safe, they happen after a continue
command returns when SelectedGoroutine and CurrentThread always agree,
but the calls in frameCommand and listCommand are wrong.
Additionally we should stop reporting an error when the debugger is
stopped on an unknown PC address.
When gdbserial can not find debugserver or lldb-server the error
message is always the same and it complains about lldb-server not being
found.
This is fine on linux (where the backend is unnecessary) but incomplete
on macOS (where the backend is actually used).
Make the error message clearer so that users who do not bother reading
install instructions are not confused.
I found this issue (https://github.com/derekparker/delve/issues/514) where user alexbrainman gave a very helpful answer. Adding this to the official install-guide might help a lot of users.
Go 1.10 added inlined calls to debug_info, this commit adds support
for DW_TAG_inlined_call to delve, both for stack traces (where
inlined calls will appear as normal stack frames) and to correct
the behavior of next, step and stepout.
The calls to Next and Frame of stackIterator continue to work
unchanged and only return real stack frames, after reading each line
appendInlinedCalls is called to unpacked all the inlined calls that
involve the current PC.
The fake stack frames produced by appendInlinedCalls are
distinguished from real stack frames by having the Inlined attribute
set to true. Also their Current and Call locations are treated
differently. The Call location will be changed to represent the
position inside the inlined call, while the Current location will
always reference the real stack frame. This is done because:
* next, step and stepout need to access the debug_info entry of
the real function they are stepping through
* we are already manipulating Call in different ways while Current
is just what we read from the call stack
The strategy remains mostly the same, we disassemble the function
and we set a breakpoint on each instruction corresponding to a
different file:line. The function in question will be the one
corresponding to the first real (i.e. non-inlined) stack frame.
* If the current function contains inlined calls, 'next' will not
set any breakpoints on instructions that belong to inlined calls. We
do not do this for 'step'.
* If we are inside an inlined call that makes other inlined
functions, 'next' will not set any breakpoints that belong to
inlined calls that are children of the current inlined call.
* If the current function is inlined the breakpoint on the return
address won't be set, because inlined frames don't have a return
address.
* The code we use for stepout doesn't work at all if we are inside
an inlined call, instead we call 'next' but instruct it to remove
all PCs belonging to the current inlined call.
* Extend the "frame" command to set the current frame.
Command
frame 3
sets up so that subsequent "print", "set", "whatis" command
will operate on frame 3.
frame 3 print foo
continues to work.
Added "up", "down". They move the current frame up or down.
Implementation note:
This changes removes "scopePrefix" mode from the terminal/command.go and instead
have the command examine the goroutine/frame value to see if it is invoked in a
scoped context.
* Rename Command.Frame -> Command.frame.
updates vendored version of x86asm, adds a symbol lookup function to
pass to the disassembler.
This will show global symbol names in the disassembly like go tool
objdump does.
Registers XMM1 and XMM2 get sometimes clobbered between the time we set
them and the panic. There is no guarantee that they won't in the go
spec so we shouldn't expect any register to keep its value. However
since this seems to only affect 1 and 2 let's try to use 9 and 10
instead.
