Step disassembles the current instruction, if it is a CALL sets a
temp breakpoint inside the called function, after the prologue and
calls Continue.
Fixes#332
- Unlike FunctionEntryToFirstLine can skip the prologue on functions
that are defined on a single line, either because they weren't
formatted or because they were autogenerated
- Can skip the prologue on most functions when setting a breakpoint
with the filename:line syntax
Fixes#396
1. A running goroutine is by definition not parked waiting for a
chan recv
2. The FDE end address is intended to be exclusive, the code
interpreted as inclusive and sometimes ended up setting a breakpoint
on a function other than the current one.
Typedefs that resolve to slices are not recorded in DWARF as typedefs
but instead as structs in a way that there is no way to know they
are really slices using debug/dwarf.
Using golang.org/x/debug/dwarf instead this problem is solved and
as a bonus some types are printed with a nicer names: (struct string
→ string, struct []int → []int, etc)
Fixes#356 and #293
Prefetch the entire memory of structs and arrays and cache it instead
of issuing readMemory calls only when we get down to primitive types.
This reduces the number of system calls to ptrace that variables makes.
Improves performance in general, greatly improving it in some
particular cases (involving large structs).
Benchmarks without prefetching:
BenchmarkArray-4 10 132189944 ns/op 0.06 MB/s
BenchmarkArrayPointer-4 5 202538503 ns/op 0.04 MB/s
BenchmarkMap-4 500 3804336 ns/op 0.27 MB/s
BenchmarkGoroutinesInfo-4 10 126397104 ns/op
BenchmarkLocalVariables-4 500 2494846 ns/op
Benchmarks with prefetching:
BenchmarkArray-4 200 10719087 ns/op 0.76 MB/s
BenchmarkArrayPointer-4 100 11931326 ns/op 0.73 MB/s
BenchmarkMap-4 1000 1466479 ns/op 0.70 MB/s
BenchmarkGoroutinesInfo-4 10 103407004 ns/op
BenchmarkLocalVariables-4 1000 1530395 ns/op
Improvement factors:
BenchmarkArray 12.33x
BenchmarkArrayPointer 16.97x
BenchmarkMap 2.59x
BenchmarkGoroutinesInfo 1.22x
BenchmarkLocalVariables 1.63x
Sometimes after PtraceSingleStep the thread does not advance of a
single instruction but is, instead, blocked immediately by a SIGSTOP
Made singleStep repeat the process until a SIGTRAP is observed.
Unsure where the SIGSTOP comes from.
Next sets its temporary breakpoints with the condition that they
must only activate on the current goroutine, and then calls Continue
When Continue encounters a temporary breakpoint it clears all
the breakpoint.
User visible changes: breakpoints that get hit while executing Next
are not ignored.
This commit does not implement full conditional breakpoints
functionality, the only condition that can be set is on the
goroutine id.
Fixes race conditions in Next affecting TestNextConcurrent.
Breakpoints are skipped either because:
1. when multiple breakpoints are hit simultaneously only one is
processed
2. a thread hits a breakpoint while another thread is being
singlestepped over the breakpoint.
Additionally fixed a race condition between Continue and tracee
termination.
Supported operators:
- All (binary and unary) operators between basic types except <-,
++ and -- (includes & to take the address of an expression)
- Comparison operators between supported compound types
- Typecast of integer constants into pointer types
- struct members
- indexing of arrays, slices and strings
- slicing of arrays, slices and strings
- pointer dereferencing
- true, false and nil constants
Implements #116, #117 and #251
Instead of trying to be clever and make an 'educated guess' as to where
the flow of control may go next, simple do the more naive, yet correct,
approach of setting a breakpoint everywhere we can in the function and
seeing where we end up. On top of this we were already setting a
breakpoint at the return address and deferred functions, so that remains
the same.
This removes a lot of gnarly, hard to maintain code and takes all the
guesswork out of this command.
Fixes#281
Only use software breakpoints for now. The reasoning is because it
complicates the code without justification, and is only supported on
Linux. Eventually, once watchpoints are properly implemented we will
revive some of this code. Also, if it is ever necessary to actually set
a hw breakpoint we can revive that code as well.
All future versions of this code will include support for OSX before
being merged back in.
Support multiple file / directory tables for multiple compilation units.
- added a type DebugLines that can hold number of DebugLineInfo
- added a supporting attribute to DebugLineInfo called 'Lookup' which is to be
used to quickly lookup if file exists in FileNames slice
- added supporting methods to lookup and return corresponding DebugLineInfo
- changed the debug_line parsing behavior to read all the available tables and
push them to DebugLines
- since Process.lineInfo is now a slice, it was breaking AllPCsBetween as well
- updated that function's definition to accept a new filename parameter to be
able to extract related DebugLineInfo
- updated calls to AllPCsBetween
- fixed tests that were broken due to attribute type change in Process
- updated _fixtures/cgotest program to include stdio.h, so that it updates
.debug_line header
- added a test to check 'next' in a cgo binary
- OSX - 1.4 does not support cgo, handle that in new testcase
This patch aims to improve how Delve tracks the current goroutine,
especially in very highly parallel programs. The main spirit of this
patch is to ensure that even in situations where the goroutine we care
about is not executing (common for len(g) > len(m)) we still end up back
on that goroutine as a result of executing the 'next' command.
We accomplish this by tracking our original goroutine id, and any time a
breakpoint is hit or a threads stops, we examine the stopped threads and
see if any are executing the goroutine we care about. If not, we set
'next' breakpoint for them again and continue them. This is done so that
one of those threads can eventually pick up the goroutine we care about
and begin executing it again.
Breakpoints, tracepoints, etc.. take a location spec as input. This
patch improves the expressiveness of that API. It allows:
* Breakpoint at line
* Breakpoint at function (handling package / receiver smoothing)
* Breakpoint at address
* Breakpoint at file:line
* Setting breakpoint based off regexp
the entry point of a function is the beginning of the prologue, which can be run multiple times for each invocation of a function if the stack needs to be expanded or the scheduler needs to be run.
