The low-level decoder might fall into an infinite decoding loop for
various reasons, the simplest being an infinite direct loop reached due
to wrong handling of self-modified code in the kernel, e.g. it might
reach
```
0x0A: pause
0x0C: jump to 0x0A
```
In this case, all the code is sequential and requires no packets to be
decoded. The low-level decoder would produce an output like the
following
```
0x0A: pause
0x0C: jump to 0x0A
0x0A: pause
0x0C: jump to 0x0A
0x0A: pause
0x0C: jump to 0x0A
... infinite amount of times
```
These cases require stopping the decoder to avoid infinite work and signal this
at least as a trace error.
- Add a check that breaks decoding of a single PSB once 500k instructions have been decoded since the last packet was processed.
- Add a check that looks for infinite loops after certain amount of instructions have been decoded since the last packet was processed.
- Add some `settings` properties for tweaking the thresholds of the checks above. This is also nice because it does the basic work needed for future settings.
- Add an AnomalyDetector class that inspects the DecodedThread and the libipt decoder in search for anomalies. These anomalies are then signaled as fatal errors in the trace.
- Add an ErrorStats class that keeps track of all the errors in a DecodedThread, with a special counter for fatal errors.
- Add an entry for decoded thread errors in the `dump info` command.
Some notes are added in the code and in the documention of the settings,
so please read them.
Besides that, I haven't been unable to create a test case in LLVM style, but
I've found an anomaly in the thread #12 of the trace
72533820-3eb8-4465-b8e4-4e6bf0ccca99 at Meta. We have to figure out how to
artificially create traces with this kind of anomalies in LLVM style.
With this change, that anomalous thread now shows:
```
(lldb)thread trace dump instructions 12 -e -i 23101
thread #12: tid = 8
...missing instructions
23101: (error) anomalous trace: possible infinite loop detected of size 2
vmlinux-5.12.0-0_fbk8_clang_6656_gc85768aa64da`panic_smp_self_stop + 5 [inlined] rep_nop at processor.h:13:2
23100: 0xffffffff81342785 pause
vmlinux-5.12.0-0_fbk8_clang_6656_gc85768aa64da`panic_smp_self_stop + 7 at panic.c:87:2
23099: 0xffffffff81342787 jmp 0xffffffff81342785 ; <+5> [inlined] rep_nop at processor.h:13:2
vmlinux-5.12.0-0_fbk8_clang_6656_gc85768aa64da`panic_smp_self_stop + 5 [inlined] rep_nop at processor.h:13:2
23098: 0xffffffff81342785 pause
vmlinux-5.12.0-0_fbk8_clang_6656_gc85768aa64da`panic_smp_self_stop + 7 at panic.c:87:2
23097: 0xffffffff81342787 jmp 0xffffffff81342785 ; <+5> [inlined] rep_nop at processor.h:13:2
vmlinux-5.12.0-0_fbk8_clang_6656_gc85768aa64da`panic_smp_self_stop + 5 [inlined] rep_nop at processor.h:13:2
23096: 0xffffffff81342785 pause
vmlinux-5.12.0-0_fbk8_clang_6656_gc85768aa64da`panic_smp_self_stop + 7 at panic.c:87:2
23095: 0xffffffff81342787 jmp 0xffffffff81342785 ; <+5> [inlined] rep_nop at processor.h:13:2
```
It used to be in an infinite loop where the decoder never stopped.
Besides that, the dump info command shows
```
(lldb) thread trace dump info 12
Errors:
Number of individual errors: 32
Number of fatal errors: 1
Number of other errors: 31
```
and in json format
```
(lldb) thread trace dump info 12 -j
"errors": {
"totalCount": 32,
"libiptErrors": {},
"fatalErrors": 1,
"otherErrors": 31
}
```
Differential Revision: https://reviews.llvm.org/D136557
The diagnostic events were heavily inspired by the progress events and
several comments incorrectly referenced "progress" rather than
"diagnostic" events.
This reverts commit 0205aa4a02570dfeda5807f66756ebdbb102744b because it
breaks TestArray.py:
a->c = <parent failed to evaluate: parent is NULL>
I decided to revert instead of disable the test because it looks like a
legitimate issue with the patch.
This change fixes two issues in ValueObject::GetExpressionPath method:
1. Accessing members of struct references used to produce expression
paths such as "str.&str.member" (instead of the expected
"str.member"). This is fixed by assigning the flag tha the child
value is a dereference when calling Dereference() on references
and adjusting logic in expression path creation.
2. If the parent of member access is dereference, the produced
expression path was "*(ptr).member". This is incorrect, since it
dereferences the member instead of the pointer. This is fixed by
wrapping dereference expression into parenthesis, resulting with
"(*ptr).member".
Reviewed By: werat, clayborg
Differential Revision: https://reviews.llvm.org/D132734
Making it easier to understand and harder to misuse.
This only applies to the ReadRegister(const RegisterInfo ®_info) variant.
Depends on D135671
Reviewed By: clayborg
Differential Revision: https://reviews.llvm.org/D135672
Familiar story, callers are either checking upfront that the pointer
wasn't null or not checking at all. SetValueFromData itself didn't
check either.
So make the parameter a ref and fixup the few places where a nullptr
check seems needed.
Depends on D135668
Reviewed By: clayborg
Differential Revision: https://reviews.llvm.org/D135670
WriteRegister and WriteRegisterUnsigned were never pased nullptr,
and only one of them appeared to handle it. Switch to ref to make
the intent clear.
Depends on D134962
Reviewed By: clayborg
Differential Revision: https://reviews.llvm.org/D134963
ReadRegister and ReadRegisterAsUnsigned are always passed valid pointers,
so the parameter should be a ref to make the intent clear.
Reviewed By: clayborg
Differential Revision: https://reviews.llvm.org/D134962
This change fixes two issues in ValueObject::GetExpressionPath method:
1. Accessing members of struct references used to produce expression
paths such as "str.&str.member" (instead of the expected
"str.member"). This is fixed by assigning the flag tha the child
value is a dereference when calling Dereference() on references
and adjusting logic in expression path creation.
2. If the parent of member access is dereference, the produced
expression path was "*(ptr).member". This is incorrect, since it
dereferences the member instead of the pointer. This is fixed by
wrapping dereference expression into parenthesis, resulting with
"(*(ptr)).member".
Reviewed By: werat, clayborg
Differential Revision: https://reviews.llvm.org/D132734
All callers have been converted to the optional version.
Depends on D134540
Reviewed By: clayborg
Differential Revision: https://reviews.llvm.org/D134541
We have some 500 ish uses of the bool plus ref version
so changing them all at once isn't a great idea.
This adds an overload that doesn't take a RegisterInfo&
and returns an optional.
Once I'm done switching all the existing callers I'll
remove the original function.
Benefits of optional over bool plus ref:
* The intent of the function is clear from the prototype.
* It's harder to forget to check if the return is valid,
and if you do you'll get an assert.
* You don't hide ununsed variables, which happens because
passing by ref marks a variable used.
* You can't forget to reset the RegisterInfo in between
calls.
Reviewed By: clayborg
Differential Revision: https://reviews.llvm.org/D134536
This is the first step to being able to handle non
trivial types in the union.
info_type effects the lifetime of the objects in the union,
so making it private means we know you have to call one of the
Set<...> functions to change it.
Reviewed By: clayborg
Differential Revision: https://reviews.llvm.org/D134039
Add support for recognizing a platform binary in the ObjectFileMachO
method that parses the "load binary" LC_NOTEs in a corefile.
A bit of reorganization to ProcessMachCore::DoLoadCore to separate
all of the unrelated things being done in that method into their own
separate methods, as well as small fixes to improve the handling of
a corefile with multiple kernel images in the corefile.
Differential Revision: https://reviews.llvm.org/D133680
rdar://98754861
Modify `SBTypeNameSpecifier` and `lldb_private::TypeMatcher` so they
have an enum value for the type of matching to perform instead of an
`m_is_regex` boolean value.
This change paves the way for introducing formatter matching based on
the result of a python callback in addition to the existing name-based
matching. See the RFC thread at
https://discourse.llvm.org/t/rfc-python-callback-for-data-formatters-type-matching/64204
for more details.
Differential Revision: https://reviews.llvm.org/D133240
I went over the output of the following mess of a command:
(ulimit -m 2000000; ulimit -v 2000000; git ls-files -z | parallel
--xargs -0 cat | aspell list --mode=none --ignore-case | grep -E
'^[A-Za-z][a-z]*$' | sort | uniq -c | sort -n | grep -vE '.{25}' |
aspell pipe -W3 | grep : | cut -d' ' -f2 | less)
and proceeded to spend a few days looking at it to find probable typos
and fixed a few hundred of them in all of the llvm project (note, the
ones I found are not anywhere near all of them, but it seems like a
good start).
Differential revision: https://reviews.llvm.org/D131122
Summary:
Many times when debugging variables might not be available even though a user can successfully set breakpoints and stops somewhere. Letting the user know will help users fix these kinds of issues and have a better debugging experience.
Examples of this include:
- enabling -gline-tables-only and being able to set file and line breakpoints and yet see no variables
- unable to open object file for DWARF in .o file debugging for darwin targets due to modification time mismatch or not being able to locate the N_OSO file.
This patch adds an new API to SBValueList:
lldb::SBError lldb::SBValueList::GetError();
object so that if you request a stack frame's variables using SBValueList SBFrame::GetVariables(...), you can get an error the describes why the variables were not available.
This patch adds the ability to get an error back when requesting variables from a lldb_private::StackFrame when calling GetVariableList.
It also now shows an error in response to "frame variable" if we have debug info and are unable to get varialbes due to an error as mentioned above:
(lldb) frame variable
error: "a.o" object from the "/tmp/libfoo.a" archive: either the .o file doesn't exist in the archive or the modification time (0x63111541) of the .o file doesn't match
Reviewers: labath JDevlieghere aadsm yinghuitan jdoerfert sscalpone
Subscribers:
Differential Revision: https://reviews.llvm.org/D133164
This patch adds new SBDebugger::GetSetting() API which
enables client to access settings as SBStructedData.
Implementation wise, a new ToJSON() virtual function is added to OptionValue
class so that each concrete child class can override and provides its
own JSON representation. This patch aims to define the APIs and implement
a common set of OptionValue child classes, leaving the remaining for
future patches.
This patch is used later by auto deduce source map from source line breakpoint
feature for testing generated source map entries.
Differential Revision: https://reviews.llvm.org/D133038
Many times when debugging variables might not be available even though a user can successfully set breakpoints and stops somewhere. Letting the user know will help users fix these kinds of issues and have a better debugging experience.
Examples of this include:
- enabling -gline-tables-only and being able to set file and line breakpoints and yet see no variables
- unable to open object file for DWARF in .o file debugging for darwin targets due to modification time mismatch or not being able to locate the N_OSO file.
This patch adds an new API to SBValueList:
lldb::SBError lldb::SBValueList::GetError();
object so that if you request a stack frame's variables using SBValueList SBFrame::GetVariables(...), you can get an error the describes why the variables were not available.
This patch adds the ability to get an error back when requesting variables from a lldb_private::StackFrame when calling GetVariableList.
It also now shows an error in response to "frame variable" if we have debug info and are unable to get varialbes due to an error as mentioned above:
(lldb) frame variable
error: "a.o" object from the "/tmp/libfoo.a" archive: either the .o file doesn't exist in the archive or the modification time (0x63111541) of the .o file doesn't match
Differential Revision: https://reviews.llvm.org/D133164
Complete support of the binary-addresses key in the qProcessInfo packet
in ProcessGDBRemote, for detecting if one of the binaries needs to be
handled by a Platform plugin, and can be used to set the Process'
DynamicLoader plugin and the Target's Platform plugin.
Implement this method in PlatformDarwinKernel to recognize a kernel
fileset at that address, find the actual kernel address in the
fileset, set DynamicLoaderDarwinKernel and PlatformDarwinKernel
in the Process/Target; register the kernel address with the dynamic
loader so it will be loaded later during attach.
This patch only addresses the live debug scenario with a gdb remote
serial protocol connection. I'll handle corefiles in a subsequent
patch that builds on this.
Differential Revision: https://reviews.llvm.org/D133534
rdar://98754861
The Read function could end up blocking if data (or EOF) arrived just as
it was about to start waiting for the events. This was only discovered
now, because we did not have unit tests for this functionality before.
We need to check for data *after* we start listening for incoming
events. There were no changes to the read thread code needed, as we
already use this pattern in SynchronizeWithReadThread, so I just updated
the comments to make it clear that it is used for reading as well.
Differential Revision: https://reviews.llvm.org/D133410
Split the read thread support from Communication into a dedicated
ThreadedCommunication subclass. The read thread support is used only
by a subset of Communication consumers, and it adds a lot of complexity
to the base class. Furthermore, having a dedicated subclass makes it
clear whether a particular consumer needs to account for the possibility
of read thread being running or not.
The modules currently calling `StartReadThread()` are updated to use
`ThreadedCommunication`. The remaining modules use the simplified
`Communication` class.
`SBCommunication` is changed to use `ThreadedCommunication` in order
to avoid changing the public API.
`CommunicationKDP` is updated in order to (hopefully) compile with
the new code. However, I do not have a Darwin box to test it, so I've
limited the changes to the bare minimum.
`GDBRemoteCommunication` is updated to become a `Broadcaster` directly.
Since it does not inherit from `ThreadedCommunication`, its event
support no longer collides with the one used for read thread and can
be implemented cleanly. The support for
`eBroadcastBitReadThreadDidExit` is removed from the code -- since
the read thread was not used, this event was never reported.
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D133251
Ensure that the ConnectionStatus and Status from
Communication::ReadThread() is correctly passed to ::Read() in order
to fix further discrepancies between ::Read() calls in non-threaded
and threaded modes.
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D132577
Previously, depending on how you constructed a UUID from data or a
StringRef, an input value of all zeros was valid (e.g. setFromData)
or not (e.g. setFromOptionalData). Since there was no way to tell
which interpretation to use, it was done somewhat inconsistently.
This standardizes the meaning of a UUID of all zeros to Not Valid,
and removes all the Optional methods and their uses, as well as the
static factories that supported them.
Differential Revision: https://reviews.llvm.org/D132191
This patch teaches LLDB about Mach-O filesets. Filsets are Mach-O files
that contain a bunch of other Mach-O files. Unlike universal binaries,
which have a different header, Filesets use load commands to describe
the different entries it contains.
Differential revision: https://reviews.llvm.org/D132433
Harmonize the status and error values of Communication::Read() when
running with and without read thread. Prior to this change, Read()
would return eConnectionStatusSuccess if read thread was enabled
and the read timed out or reached end-of-file, rather than
the respective states that are returned if read thread was disabled.
Now, it correctly returns eConnectionStatusTimedOut
and eConnectionStatusEndOfFile, and sets the error respectively.
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D132217
On macOS, LLDB uses the DebugSymbols.framework to locate symbol rich
dSYM bundles. [1] The framework uses a variety of methods, one of them
calling into a binary or shell script to locate (and download) dSYMs.
Internally at Apple, that tool is called dsymForUUID and for simplicity
I'm just going to refer to it that way here too, even though it can be
be an arbitrary executable.
The most common use case for dsymForUUID is to fetch symbols from the
network. This can take a long time, and because the calls to the
DebugSymbols.framework are blocking, it takes a while to launch the
process. This is expected and therefore many people don't use this
functionality, but instead use add-dsym when they want symbols for a
given frame, backtrace or module. This is a little faster because you're
only fetching symbols for the module you care about, but it's still a
slow, blocking operation.
This patch introduces a hybrid approach between the two. When
symbols.enable-background-lookup is enabled, lldb will do the equivalent
of add-dsym in the background for every module that shows up in the
backtrace but doesn't have symbols for. From the user's perspective
there is no slowdown, because the process launches immediately, with
whatever symbols are available. Meanwhile, more symbol information is
added over time as the background fetching completes.
[1] https://lldb.llvm.org/use/symbols.html
rdar://76241471
Differential revision: https://reviews.llvm.org/D131328
Use the Initialize/Terminate pattern for the global thread pool to make
sure it gets flushed during teardown.
Differential revision: https://reviews.llvm.org/D131407
Currently a FileSpecList::FindFileIndex(...) will only match the specified FileSpec if:
- it has filename and directory and both match exactly
- if has a filename only and any filename in the list matches
Because of this, we modify our breakpoint resolving so it can handle relative paths by doing some extra code that removes the directory from the FileSpec when searching if the path is relative.
This patch is intended to fix breakpoints so they work as users expect them to by adding the following features:
- allow matches to relative paths in the file list to match as long as the relative path is at the end of the specified path at valid directory delimiters
- allow matches to paths to match if the specified path is relative and shorter than the file paths in the list
This allows us to remove the extra logic from BreakpointResolverFileLine.cpp that added support for setting breakpoints with relative paths.
This means we can still set breakpoints with relative paths when the debug info contains full paths. We add the ability to set breakpoints with full paths when the debug info contains relative paths.
Debug info contains "./a/b/c/main.cpp", the following will set breakpoints successfully:
- /build/a/b/c/main.cpp
- a/b/c/main.cpp
- b/c/main.cpp
- c/main.cpp
- main.cpp
- ./c/main.cpp
- ./a/b/c/main.cpp
- ./b/c/main.cpp
- ./main.cpp
This also ensures that we won't match partial directory names, if a relative path is in the list or is used for the match, things must match at the directory level.
The breakpoint resolving code will now use the new FileSpecList::FindCompatibleIndex(...) function to allow this fuzzy matching to work for breakpoints.
Differential Revision: https://reviews.llvm.org/D130401
This reverts commit 967df65a3610f98a3bc0ec0f2303641d7bad176c.
This fixes test/Shell/SymbolFile/NativePDB/find-functions.cpp. When
looking up functions with the PDB plugins, if we are looking for a
full function name, we should use `GetName` to populate the `name`
field instead of `GetLookupName` since `GetName` has the more
complete information.
This reverts commit befa77e59a7760d8c4fdd177b234e4a59500f61c.
Looks like this broke a SymbolFileNativePDB test. I'll investigate and
resubmit with a fix soon.
Context:
When setting a breakpoint by name, we invoke Module::FindFunctions to
find the function(s) in question. However, we use a Module::LookupInfo
to first process the user-provided name and figure out exactly what
we're looking for. When we actually perform the function lookup, we
search for the basename. After performing the search, we then filter out
the results using Module::LookupInfo::Prune. For example, given
a:🅱️:foo we would first search for all instances of foo and then filter
out the results to just names that have a:🅱️:foo in them. As one can
imagine, this involves a lot of debug info processing that we do not
necessarily need to be doing. Instead of doing one large post-processing
step after finding each instance of `foo`, we can filter them as we go
to save time.
Some numbers:
Debugging LLDB and placing a breakpoint on
llvm::itanium_demangle::StringView::begin without this change takes
approximately 70 seconds and resolves 31,920 DIEs. With this change,
placing the breakpoint takes around 30 seconds and resolves 8 DIEs.
Differential Revision: https://reviews.llvm.org/D129682
It may be useful to search symbol table entries by mangled instead
of demangled names. Add this optional functionality in the SymbolTable
functions.
Differential Revision: https://reviews.llvm.org/D130803
Add support to Mach-O corefiles and to live gdb remote serial protocol
connections for the corefile/remote stub to provide a list of load
addresses of binaries that should be found & loaded by lldb, and nothing
else. lldb will try to parse the binary out of memory, and if it can
find a UUID, try to find a binary & its debug information based on the
UUID, falling back to using the memory image if it must.
A bit of code unification from three parts of lldb that were loading
individual binaries already, so there is a shared method in
DynamicLoader to handle all of the variations they were doing.
Re-landing this with a uuid_is_null() implementation added to
Utility/UuidCompatibility.h for non-Darwin systems.
Differential Revision: https://reviews.llvm.org/D130813
rdar://94249937
rdar://94249384
This reverts commit d8879fba8825b9799166ba0ea552d4027bfb8ad1.
Debian bot failure; I included <uuid/uuid.h> to get uuid_is_null() but
don't get it there. Will memcmp or whatever & recommit.
Add support to Mach-O corefiles and to live gdb remote serial protocol
connections for the corefile/remote stub to provide a list of load
addresses of binaries that should be found & loaded by lldb, and nothing
else. lldb will try to parse the binary out of memory, and if it can
find a UUID, try to find a binary & its debug information based on the
UUID, falling back to using the memory image if it must.
A bit of code unification from three parts of lldb that were loading
individual binaries already, so there is a shared method in
DynamicLoader to handle all of the variations they were doing.
Differential Revision: https://reviews.llvm.org/D130813
rdar://94249937
rdar://94249384
Resubmission of https://reviews.llvm.org/D130309 with the 2 patches that fixed the linux buildbot, and new windows fixes.
The FileSpec APIs allow users to modify instance variables directly by getting a non const reference to the directory and filename instance variables. This makes it impossible to control all of the times the FileSpec object is modified so we can clear cached member variables like m_resolved and with an upcoming patch caching if the file is relative or absolute. This patch modifies the APIs of FileSpec so no one can modify the directory or filename instance variables directly by adding set accessors and by removing the get accessors that are non const.
Many clients were using FileSpec::GetCString(...) which returned a unique C string from a ConstString'ified version of the result of GetPath() which returned a std::string. This caused many locations to use this convenient function incorrectly and could cause many strings to be added to the constant string pool that didn't need to. Most clients were converted to using FileSpec::GetPath().c_str() when possible. Other clients were modified to use the newly renamed version of this function which returns an actualy ConstString:
ConstString FileSpec::GetPathAsConstString(bool denormalize = true) const;
This avoids the issue where people were getting an already uniqued "const char *" that came from a ConstString only to put the "const char *" back into a "ConstString" object. By returning the ConstString instead of a "const char *" clients can be more efficient with the result.
The patch:
- Removes the non const GetDirectory() and GetFilename() get accessors
- Adds set accessors to replace the above functions: SetDirectory() and SetFilename().
- Adds ClearDirectory() and ClearFilename() to replace usage of the FileSpec::GetDirectory().Clear()/FileSpec::GetFilename().Clear() call sites
- Fixed all incorrect usage of FileSpec::GetCString() to use FileSpec::GetPath().c_str() where appropriate, and updated other call sites that wanted a ConstString to use the newly returned ConstString appropriately and efficiently.
Differential Revision: https://reviews.llvm.org/D130549
