This PR introduces a new `ThreadPlanSingleThreadTimeout` that will be
used to address potential deadlock during single-thread stepping.
While debugging a target with a non-trivial number of threads (around
5000 threads in one example target), we noticed that a simple step over
can take as long as 10 seconds. Enabling single-thread stepping mode
significantly reduces the stepping time to around 3 seconds. However,
this can introduce deadlock if we try to step over a method that depends
on other threads to release a lock.
To address this issue, we introduce a new
`ThreadPlanSingleThreadTimeout` that can be controlled by the
`target.process.thread.single-thread-plan-timeout` setting during
single-thread stepping mode. The concept involves counting the elapsed
time since the last internal stop to detect overall stepping progress.
Once a timeout occurs, we assume the target is not making progress due
to a potential deadlock, as mentioned above. We then send a new async
interrupt, resume all threads, and `ThreadPlanSingleThreadTimeout`
completes its task.
To support this design, the major changes made in this PR are:
1. `ThreadPlanSingleThreadTimeout` is popped during every internal stop
and reset (re-pushed) to the top of the stack (as a leaf node) during
resume. This is achieved by always returning `true` from
`ThreadPlanSingleThreadTimeout::DoPlanExplainsStop()` and
`ThreadPlanSingleThreadTimeout::MischiefManaged()`.
2. A new thread-specific async interrupt stop is introduced, which can
be detected/consumed by `ThreadPlanSingleThreadTimeout`.
3. The clearing of branch breakpoints in the range thread plan has been
moved from `DoPlanExplainsStop()` to `ShouldStop()`, as it is not
guaranteed that it will be called.
The detailed design is discussed in the RFC below:
[https://discourse.llvm.org/t/improve-single-thread-stepping/74599](https://discourse.llvm.org/t/improve-single-thread-stepping/74599)
---------
Co-authored-by: jeffreytan81 <jeffreytan@fb.com>
This is an improved attempt to improve the semantics of SupportFile
equivalence, taking into account the feedback from #95606.
Pavel's comment about the lack of a concise name because the concept
isn't trivial made me realize that I don't want to abstract this concept
away behind a helper function. Instead, I opted for a rather verbose
enum that forces the caller to consider exactly what kind of comparison
is appropriate for every call.
Store a SupportFile, rather than a FileSpec, in LineEntry. This commit
works towards having the SourceManageroperate on SupportFiles so that it
can (1) validate the Checksum and (2) materialize the content of inline
source information.
Most of our code was including Log.h even though that is not where the
"lldb" log channel is defined (Log.h defines the generic logging
infrastructure). This worked because Log.h included Logging.h, even
though it should.
After the recent refactor, it became impossible the two files include
each other in this direction (the opposite inclusion is needed), so this
patch removes the workaround that was put in place and cleans up all
files to include the right thing. It also renames the file to LLDBLog to
better reflect its purpose.
Summary:
This patch improves step over performance for the case when we are
stepping over a call with a next-branch-breakpoint (see
https://reviews.llvm.org/D58678), and we encounter a stop during the
call. Currently, this causes the thread plan to step-out //each frame//
until it reaches the step-over range. This is a regression introduced by
https://reviews.llvm.org/D58678 (which did improve other things!). Prior
to that change, the step-over plan would always step-out just once.
With this patch, if we find ourselves stopped in a deeper stack frame
and we already have a next branch breakpoint, we simply return from the
step-over plan's ShouldStop handler without pushing the step out plan.
In my experiments this improved the time of stepping over a call that
loads 12 dlls from 14s to 5s. This was in remote debugging scenario with
10ms RTT, the call in question was Vulkan initialization
(vkCreateInstance), which loads various driver dlls. Loading those dlls
must stop on the rendezvous breakpoint, causing the perf problem
described above.
Reviewers: clayborg, labath, jingham
Reviewed By: jingham
Subscribers: lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D76216
Summary:
A *.cpp file header in LLDB (and in LLDB) should like this:
```
//===-- TestUtilities.cpp -------------------------------------------------===//
```
However in LLDB most of our source files have arbitrary changes to this format and
these changes are spreading through LLDB as folks usually just use the existing
source files as templates for their new files (most notably the unnecessary
editor language indicator `-*- C++ -*-` is spreading and in every review
someone is pointing out that this is wrong, resulting in people pointing out that this
is done in the same way in other files).
This patch removes most of these inconsistencies including the editor language indicators,
all the different missing/additional '-' characters, files that center the file name, missing
trailing `===//` (mostly caused by clang-format breaking the line).
Reviewers: aprantl, espindola, jfb, shafik, JDevlieghere
Reviewed By: JDevlieghere
Subscribers: dexonsmith, wuzish, emaste, sdardis, nemanjai, kbarton, MaskRay, atanasyan, arphaman, jfb, abidh, jsji, JDevlieghere, usaxena95, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D73258
Summary:
Yet another step on the long road towards getting rid of lldb's Stream class.
We probably should just make this some kind of member of Address/AddressRange, but it seems quite often we just push
in random integers in there and this is just about getting rid of Stream and not improving arbitrary APIs.
I had to rename another `DumpAddress` function in FormatEntity that is dumping the content of an address to make Clang happy.
Reviewers: labath
Reviewed By: labath
Subscribers: JDevlieghere, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D71052
This patch replaces explicit calls to log::Printf with the new LLDB_LOGF
macro. The macro is similar to LLDB_LOG but supports printf-style format
strings, instead of formatv-style format strings.
So instead of writing:
if (log)
log->Printf("%s\n", str);
You'd write:
LLDB_LOG(log, "%s\n", str);
This change was done mechanically with the command below. I replaced the
spurious if-checks with vim, since I know how to do multi-line
replacements with it.
find . -type f -name '*.cpp' -exec \
sed -i '' -E 's/log->Printf\(/LLDB_LOGF\(log, /g' "{}" +
Differential revision: https://reviews.llvm.org/D65128
llvm-svn: 366936
A lot of comments in LLDB are surrounded by an ASCII line to delimit the
begging and end of the comment.
Its use is not really consistent across the code base, sometimes the
lines are longer, sometimes they are shorter and sometimes they are
omitted. Furthermore, it looks kind of weird with the 80 column limit,
where the comment actually extends past the line, but not by much.
Furthermore, when /// is used for Doxygen comments, it looks
particularly odd. And when // is used, it incorrectly gives the
impression that it's actually a Doxygen comment.
I assume these lines were added to improve distinguishing between
comments and code. However, given that todays editors and IDEs do a
great job at highlighting comments, I think it's worth to drop this for
the sake of consistency. The alternative is fixing all the
inconsistencies, which would create a lot more churn.
Differential revision: https://reviews.llvm.org/D60508
llvm-svn: 358135
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
This patch simplifies boolean expressions acorss LLDB. It was generated
using clang-tidy with the following command:
run-clang-tidy.py -checks='-*,readability-simplify-boolean-expr' -format -fix $PWD
Differential revision: https://reviews.llvm.org/D55584
llvm-svn: 349215
When debugging read-only memory we cannot use software breakpoint. We
already have support for hardware breakpoints and users can specify them
with `-H`. However, there's no option to force LLDB to use hardware
breakpoints internally, for example while stepping.
This patch adds a setting target.require-hardware-breakpoint that forces
LLDB to always use hardware breakpoints. Because hardware breakpoints
are a limited resource and can fail to resolve, this patch also extends
error handling in thread plans, where breakpoints are used for stepping.
Differential revision: https://reviews.llvm.org/D54221
llvm-svn: 346920
This patch removes the comments grouping header includes. They were
added after running IWYU over the LLDB codebase. However they add little
value, are often outdates and burdensome to maintain.
llvm-svn: 346626
This is intended as a clean up after the big clang-format commit
(r280751), which unfortunately resulted in many of the comment
paragraphs in LLDB being very hard to read.
FYI, the script I used was:
import textwrap
import commands
import os
import sys
import re
tmp = "%s.tmp"%sys.argv[1]
out = open(tmp, "w+")
with open(sys.argv[1], "r") as f:
header = ""
text = ""
comment = re.compile(r'^( *//) ([^ ].*)$')
special = re.compile(r'^((([A-Z]+[: ])|([0-9]+ )).*)|(.*;)$')
for line in f:
match = comment.match(line)
if match and not special.match(match.group(2)):
# skip intentionally short comments.
if not text and len(match.group(2)) < 40:
out.write(line)
continue
if text:
text += " " + match.group(2)
else:
header = match.group(1)
text = match.group(2)
continue
if text:
filled = textwrap.wrap(text, width=(78-len(header)),
break_long_words=False)
for l in filled:
out.write(header+" "+l+'\n')
text = ""
out.write(line)
os.rename(tmp, sys.argv[1])
Differential Revision: https://reviews.llvm.org/D46144
llvm-svn: 331197
All references to Host and Core have been removed, so this
class can now safely be lowered into Utility.
Differential Revision: https://reviews.llvm.org/D30559
llvm-svn: 296909
This moves the following classes from Core -> Utility.
ConstString
Error
RegularExpression
Stream
StreamString
The goal here is to get lldbUtility into a state where it has
no dependendencies except on itself and LLVM, so it can be the
starting point at which to start untangling LLDB's dependencies.
These are all low level and very widely used classes, and
previously lldbUtility had dependencies up to lldbCore in order
to use these classes. So moving then down to lldbUtility makes
sense from both the short term and long term perspective in
solving this problem.
Differential Revision: https://reviews.llvm.org/D29427
llvm-svn: 293941
Summary:
Fix step-over when SymbolContext.function is missing and symbol is present.
With targets from our build configuration,
ThreadPlanStepOverRange::IsEquivalentContext fails to fire for relevant frames,
leading to ShouldStop() returning true prematurely.
The frame's SymbolContext, and m_addr_context have:
- comp_unit set and matching
- function = nullptr
- symbol set and matching (but this is never checked)
My naive guess is that the context should be equivalent in this case :-)
Reviewers: jingham
Subscribers: lldb-commits
Differential Revision: https://reviews.llvm.org/D26804
llvm-svn: 287274
This is a large API change that removes the two functions from
StreamString that return a std::string& and a const std::string&,
and instead provide one function which returns a StringRef.
Direct access to the underlying buffer violates the concept of
a "stream" which is intended to provide forward only access,
and makes porting to llvm::raw_ostream more difficult in the
future.
Differential Revision: https://reviews.llvm.org/D26698
llvm-svn: 287152
*** to conform to clang-format’s LLVM style. This kind of mass change has
*** two obvious implications:
Firstly, merging this particular commit into a downstream fork may be a huge
effort. Alternatively, it may be worth merging all changes up to this commit,
performing the same reformatting operation locally, and then discarding the
merge for this particular commit. The commands used to accomplish this
reformatting were as follows (with current working directory as the root of
the repository):
find . \( -iname "*.c" -or -iname "*.cpp" -or -iname "*.h" -or -iname "*.mm" \) -exec clang-format -i {} +
find . -iname "*.py" -exec autopep8 --in-place --aggressive --aggressive {} + ;
The version of clang-format used was 3.9.0, and autopep8 was 1.2.4.
Secondly, “blame” style tools will generally point to this commit instead of
a meaningful prior commit. There are alternatives available that will attempt
to look through this change and find the appropriate prior commit. YMMV.
llvm-svn: 280751
frame to another was triggering an early stop when stepping back out to a
real frame. Check that we're doing this only for inlined frames.
<rdar://problem/26482931>
llvm-svn: 277185
Summary:
The "file" variable in a LineEntry was mapped using target.source-map, except when stepping through inlined code. This patch adds a new variable to LineEntry, "original_file", that contains the original file from the debug info. "file" will continue to (possibly) be mapped.
Some code has been changed to use "original_file". This is code dealing with symbols. Code dealing with source files will still use "file". Reviewers, please confirm that these particular changes are correct.
Tests run on Ubuntu 12.04 show no regression.
Reviewers: clayborg, jingham
Subscribers: lldb-commits
Differential Revision: http://reviews.llvm.org/D20135
llvm-svn: 269250
with the one change that ThreadPlanStepOut::ThreadPlanStepOut
will now only advance the return address breakpoint to
the end of a source line, if we have source line debug information.
It will not advance to the end of a Symbol if we lack source line
information. This, or the recognition of the LEAVE instruction
in r257209, would have fixed the regression that Siva was seeing.
Both were good changes, so I've made both.
Original commit message:
Performance improvement: Change lldb so that it puts a breakpoint
on the first branch instruction after a function return (or the end
of a source line), instead of a breakpoint on the return address,
to skip an extra stop & start of the inferior process.
I changed Process::AdvanceAddressToNextBranchInstruction to not
take an optional InstructionList argument - no callers are providing
a cached InstructionList today, and if this function was going to
do that, the right thing to do would be to fill out / use a
DisassemblerSP which is a disassembler with the InstructionList for
this address range.
http://reviews.llvm.org/D15708
<rdar://problem/23309838>
llvm-svn: 257210
puts a breakpoint" it is causing a regression in the TestStepNoDebug
test case on ubuntu 14.04 with gcc 4.9.2. Thanks for the email
Siva. I'll recommit when I've figured out the regression.
llvm-svn: 257138
on the first branch instruction after a function return (or the end
of a source line), instead of a breakpoint on the return address,
to skip an extra stop & start of the inferior process.
I changed Process::AdvanceAddressToNextBranchInstruction to not
take an optional InstructionList argument - no callers are providing
a cached InstructionList today, and if this function was going to
do that, the right thing to do would be to fill out / use a
DisassemblerSP which is a disassembler with the InstructionList for
this address range.
http://reviews.llvm.org/D15708
<rdar://problem/23309838>
llvm-svn: 257117
but that wasn't added to the list of reasons they don't explain. That
would mean we keep stepping after hitting the AsanDie breakpoint rather
than stopping when the Asan event occurred.
<rdar://problem/21925479>
llvm-svn: 243035
So that we don't have to update every single #include in the entire
codebase to #include this new header (which used to get included by
lldb-private-log.h, we automatically #include "Logging.h" from
within "Log.h".
llvm-svn: 232653
the user level. It adds the ability to invent new stepping modes implemented by python classes,
and to view the current thread plan stack and to some extent alter it.
I haven't gotten to documentation or tests yet. But this should not cause any behavior changes
if you don't use it, so its safe to check it in now and work on it incrementally.
llvm-svn: 218642
the same parent frame, but different current frame - e.g. when
you step past a tail call exit from a function. Apply the same
"avoid-no-debug" rules to this case as for a "step-in".
<rdar://problem/16189225>
llvm-svn: 214946
for customizing "step-in" behavior (e.g. step-in doesn't step into code with no debug info), but also
the behavior of step-in/step-out and step-over when they step out of the frame they started in.
I also added as a proof of concept of this reworking a mode for stepping where stepping out of a frame
into a frame with no debug information will continue stepping out till it arrives at a frame that does
have debug information. This is useful when you are debugging callback based code where the callbacks
are separated from the code that initiated them by some library glue you don't care about, among other
things.
llvm-svn: 203747
pure virtual base class and made StackFrame a subclass of that. As
I started to build on top of that arrangement today, I found that it
wasn't working out like I intended. Instead I'll try sticking with
the single StackFrame class -- there's too much code duplication to
make a more complicated class hierarchy sensible I think.
llvm-svn: 193983
defines a protocol that all subclasses will implement. StackFrame
is currently the only subclass and the methods that Frame vends are
nearly identical to StackFrame's old methods.
Update all callers to use Frame*/Frame& instead of pointers to
StackFrames.
This is almost entirely a mechanical change that touches a lot of
the code base so I'm committing it alone. No new functionality is
added with this patch, no new subclasses of Frame exist yet.
I'll probably need to tweak some of the separation, possibly moving
some of StackFrame's methods up in to Frame, but this is a good
starting point.
<rdar://problem/15314068>
llvm-svn: 193907
- searches frames beginning from the current frame, stops when an equivalent context is found
- not using GetStackFrameCount() for performance reasons
- fixes TestInlineStepping (clang/gcc buildbots)
llvm-svn: 190868
From Jim's post on the lldb-dev mailing list:
This code is there as a backstop for when the unwinder drops a frame at
the beginning of new function/trampoline or whatever.
In the (older_ctx_is_equivalent == false) case we will see if we are at
a trampoline function that somebody knows how to get out of, and
otherwise we will stop.
llvm-svn: 190149
plan providers from a "ThreadPlan *" to a "lldb::ThreadPlanSP". That was needed to fix
a bug where the ThreadPlanStepInRange wasn't checking with its sub-plans to make sure they
succeed before trying to proceed further. If the sub-plan failed and as a result didn't make
any progress, you could end up retrying the same failing algorithm in an infinite loop.
<rdar://problem/14043602>
llvm-svn: 186618
value. This fixes problems, for instance, with the StepRange plans, where they know that
they explained the stop because they were at their "run to here" breakpoint, then deleted
that breakpoint, so when they got asked again, doh! I had done this for a couple of plans
in an ad hoc fashion, this just formalizes it.
Also add a "ResumeRequested" in Process so that the code in the completion handlers can
tell the ShouldStop logic they want to resume rather than just directly resuming. That allows
us to handle resuming in a more controlled fashion.
Also, SetPublicState can take a "restarted" flag, so that it doesn't drop the run lock when
the target was immediately restarted.
--This line, and those below , will be ignored--
M test/lang/objc/objc-dynamic-value/TestObjCDynamicValue.py
M include/lldb/Target/ThreadList.h
M include/lldb/Target/ThreadPlanStepOut.h
M include/lldb/Target/Thread.h
M include/lldb/Target/ThreadPlanBase.h
M include/lldb/Target/ThreadPlanStepThrough.h
M include/lldb/Target/ThreadPlanStepInstruction.h
M include/lldb/Target/ThreadPlanStepInRange.h
M include/lldb/Target/ThreadPlanStepOverBreakpoint.h
M include/lldb/Target/ThreadPlanStepUntil.h
M include/lldb/Target/StopInfo.h
M include/lldb/Target/Process.h
M include/lldb/Target/ThreadPlanRunToAddress.h
M include/lldb/Target/ThreadPlan.h
M include/lldb/Target/ThreadPlanCallFunction.h
M include/lldb/Target/ThreadPlanStepOverRange.h
M source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleThreadPlanStepThroughObjCTrampoline.h
M source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleThreadPlanStepThroughObjCTrampoline.cpp
M source/Target/StopInfo.cpp
M source/Target/Process.cpp
M source/Target/ThreadPlanRunToAddress.cpp
M source/Target/ThreadPlan.cpp
M source/Target/ThreadPlanCallFunction.cpp
M source/Target/ThreadPlanStepOverRange.cpp
M source/Target/ThreadList.cpp
M source/Target/ThreadPlanStepOut.cpp
M source/Target/Thread.cpp
M source/Target/ThreadPlanBase.cpp
M source/Target/ThreadPlanStepThrough.cpp
M source/Target/ThreadPlanStepInstruction.cpp
M source/Target/ThreadPlanStepInRange.cpp
M source/Target/ThreadPlanStepOverBreakpoint.cpp
M source/Target/ThreadPlanStepUntil.cpp
M lldb.xcodeproj/xcshareddata/xcschemes/Run Testsuite.xcscheme
llvm-svn: 181381
LLDB is crashing when logging is enabled from lldb-perf-clang. This has to do with the global destructor chain as the process and its threads are being torn down.
All logging channels now make one and only one instance that is kept in a global pointer which is never freed. This guarantees that logging can correctly continue as the process tears itself down.
llvm-svn: 178191
hitting auto-continue signals while running a thread plan would cause us to lose control of the debug
session.
<rdar://problem/12993641>
llvm-svn: 174793
