When a process gets restarted TypeSystem objects associated with it
may get deleted, and any CompilerType objects holding on to a
reference to that type system are a use-after-free in waiting. Because
of the SBAPI, we don't have tight control over where CompilerTypes go
and when they are used. This is particularly a problem in the Swift
plugin, where the scratch TypeSystem can be restarted while the
process is still running. The Swift plugin has a lock to prevent
abuse, but where there's a lock there can be bugs.
This patch changes CompilerType to store a std::weak_ptr<TypeSystem>.
Most of the std::weak_ptr<TypeSystem>* uglyness is hidden by
introducing a wrapper class CompilerType::WrappedTypeSystem that has a
dyn_cast_or_null() method. The only sites that need to know about the
weak pointer implementation detail are the ones that deal with
creating TypeSystems.
rdar://101505232
Differential Revision: https://reviews.llvm.org/D136650
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
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
This can cause a deadlock if other threads use the common pattern of
"lock the StackFrameList, get a frame, lock the StackFrame."
Differential Revision: https://reviews.llvm.org/D130524
The `frame variable` command supports an implicit `this`/`self`, allowing a
user to run `v some_field` instead of `v this->some_field`. However, some
languages have non-pointer `this`/`self` types (for example, Swift).
This change adds support for non-pointer implicit `this`/`self`. This is done
by consulting the type of the instance variable. If the type is known to be
non-pointer, the dot operator is used instead of the arrow operator.
The C language of families each have a pointer instance type, which makes
testing of this difficult. Tests for this feature will be done in the Swift
downstream fork, as Swift's `self` is a non-pointer (reference) type.
rdar://82095148
Reviewed By: aprantl
Differential Revision: https://reviews.llvm.org/D127605
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.
This is a post-review update for D115313, to rephrase source display
warning messages for artificial locations, making them more
understandable for the end-user.
Differential Revision: https://reviews.llvm.org/D115461
Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
It can happen that a line entry reports that some source code is located
at line 0. In DWARF, line 0 is a special location which indicates that
code has no 1-1 mapping with source.
When stopping in one of those artificial locations, lldb doesn't know which
line to display and shows the beginning of the file instead.
This patch mitigates this behaviour by checking if the current symbol context
of the line entry has a matching function, in which case, it slides the
source listing to the start of that function.
This patch also shows the user a warning explaining why lldb couldn't
show sources at that location.
rdar://83118425
Differential Revision: https://reviews.llvm.org/D115313
Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
Commiting this patch for Augusto Noronha who is getting set
up still.
This patch changes Target::ReadMemory so the default behavior
when a read is in a Section that is read-only is to fetch the
data from the local binary image, instead of reading it from
memory. Update all callers to use their old preferences
(the old prefer_file_cache bool) using the new API; we should
revisit these calls and see if they really intend to read
live memory, or if reading from a read-only Section would be
equivalent and important for performance-sensitive cases.
rdar://30634422
Differential revision: https://reviews.llvm.org/D100338
Add calls into LanguageRuntime when finding the unwind method to
use out of the 0th (currently executing) stack frame.
Allow for the LanguageRuntimes to indicate if this stack frames
should be treated like a zeroth-frame -- symbolication should be
done based on the saved pc address, not decremented like normal ABI
function calls.
Add methods to RegisterContext and StackFrame to get a pc value
suitable for symbolication, to reduce the number of places in lldb
where we decrement the saved pc values before symbolication.
<rdar://problem/70398009>
Differential Revision: https://reviews.llvm.org/D97644
In a new Range class was introduced to simplify and the Disassembler API
and reduce duplication. It unintentionally broke the
SBFrame::Disassemble functionality because it unconditionally converts
the number of instructions to a Range{Limit::Instructions,
num_instructions}. This is subtly different from the previous behavior,
where now we're passing a Range and assume it's valid in the callee, the
original code would propagate num_instructions and the callee would
compare the value and decided between disassembling instructions or
bytes.
Unfortunately the existing tests was not particularly strict:
disassembly = frame.Disassemble()
self.assertNotEqual(len(disassembly), 0, "Disassembly was empty.")
This would pass because without this patch we'd disassemble zero
instructions, resulting in an error:
(lldb) script print(lldb.frame.Disassemble())
error: error reading data from section __text
Differential revision: https://reviews.llvm.org/D89925
This cleanup patch unifies all methods called GetByteSize() in the
ValueObject hierarchy to return an optional, like the methods in
CompilerType do. This means fewer magic 0 values, which could fix bugs
down the road in languages where types can have a size of zero, such
as Swift and C (but not C++).
Differential Revision: https://reviews.llvm.org/D84285
This re-lands the patch with bogus :m_byte_size(0) initalizations removed.
This cleanup patch unifies all methods called GetByteSize() in the
ValueObject hierarchy to return an optional, like the methods in
CompilerType do. This means fewer magic 0 values, which could fix bugs
down the road in languages where types can have a size of zero, such
as Swift and C (but not C++).
Differential Revision: https://reviews.llvm.org/D84285
Summary:
Currently the frame recognizers are stored in a global list (the list in the
StackFrameRecognizersManagerImpl singleton to be precise). All commands and
plugins that modify the list are just modifying that global list of recognizers
which is shared by all Target and Debugger instances.
This is clearly against the idea of LLDB being usable as a library and it also
leads to some very obscure errors as now multiple tests are sharing the used
frame recognizers. For example D83400 is currently failing as it reorders some
test_ functions which permanently changes the frame recognizers of all
debuggers/targets. As all frame recognizers are also initialized in a 'once'
guard, it's also impossible to every restore back the original frame recognizers
once they are deleted in a process.
This patch just moves the frame recognizers into the current target. This seems
the way everyone assumes the system works as for example the assert frame
recognizers is using the current target to find the function/so-name to look for
(which only works if the recognizers are stored in the target).
Reviewers: jingham, mib
Reviewed By: jingham, mib
Subscribers: MrHate, JDevlieghere
Differential Revision: https://reviews.llvm.org/D83757
Summary:
This fixes a bug where
frame var a[0]+5
returns the value a[0] without any warning because the current logic simply ignores everything after ']' as long as there is no '.', '-' or '[' in the rest of the string.
The fix simplifies the termination condition of the expression path parsing loop to check if have a non-empty remaining string to parse. Previously, the condition checked if a separator was found. That condition coincided with the remaining string-to-parse condition except for the buggy indexed case where non-empty string was left ("+5" in the example above), but the separator index was 'npos'.
Reviewed By: teemperor, labath
Differential Revision: https://reviews.llvm.org/D79404
Fix to code from https://reviews.llvm.org/D64993.
Field StackFrame::m_behaves_like_zeroth_frame was introduced in commit
[1], however that commit hasn't added a copying of the field to
UpdatePreviousFrameFromCurrentFrame, therefore the value wouldn't change
when updating frames to reflect the current situation.
The particular scenario, where this matters is following. Assume we have
function main that invokes function func1. We set breakpoint at
func1 entry and in main after the func1 call, and do not stop at
the main entry. Therefore, when debugger stops for the first time,
func1 is frame#0, while main is frame#1, thus
m_behaves_like_zeroth_frame is set to 0 for main frame. Execution is
resumed, and stops now in main, where it is now frame#0. However while
updating the frame object, m_behaves_like_zeroth_frame remains false.
This field plays an important role when calculating line information for
backtrace: for frame#0, PC is the current line, therefore line
information is retrieved for PC, however for all other frames this is
not the case - calculated PC is a return-PC, i.e. instruction after the
function call line, therefore for those frames LLDB needs to step back
by one instruction. Initial implementation did this strictly for frames
that have index != 0 (and index is updated properly in
UpdatePreviousFrameFromCurrentFrame), but m_behaves_like_zeroth_frame
added a capability for middle-of-stack frames to behave in a similar
manner. But because current code now doesn't check frame idx,
m_behaves_like_zeroth_frame must be set to true for frames with 0 index,
not only for frame that behave like one. In the described test case,
after stopping in main, LLDB would still consider frame#0 as
non-zeroth, and would subtract instruction from the PC, and would report
previous like as current line.
The error doesn't manifest itself in LLDB interpreter though - it can be
reproduced through LLDB-MI and when using SB API, but not when we
interpreter command "continue" is executed. Honestly, I didn't fully
understand why it works in interpreter, I did found that bug "fixes"
itself if I enable DEBUG_STACK_FRAMES in StackFrameList.cpp, because
that calls StackFrame::Dump and that calls
GetSymbolContext(eSymbolContextEverything), which fills the context of
frame on the first breakpoint, therefore it doesn't have to be
recalculated (improperly) on a second frame. However, on first
breakpoint symbol context is calculated for the "call" line, not the
next one, therefore it should be recalculated anyway on a second
breakpoint, and it is done correctly, even though
m_behaves_like_zeroth_frame is still incorrect, as long as
GetSymbolContext(eSymbolContextEverything) has been called.
[1] 31e6dbe1c6 Fix PC adjustment in StackFrame::GetSymbolContext
Differential Revision: https://reviews.llvm.org/D75975
Patch by Anton Kolesov <Anton.Kolesov@synopsys.com>
Summary:
The class has two pairs of functions whose functionalities differ in
only how one specifies how much he wants to disasseble. One limits the
process by the size of the input memory region. The other based on the
total amount of instructions disassembled. They also differ in various
features (like error reporting) that were only added to one of the
versions.
There are various ways in which this could be addressed. This patch
does it by introducing a helper struct called "Limit", which is
effectively a pair specifying the value that you want to limit, and the
actual limit itself.
Reviewers: JDevlieghere
Subscribers: sdardis, jrtc27, atanasyan, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D75730
Some functions in this file only use the "target" component of an
execution context. Adjust the argument lists to reflect that.
This avoids some defensive null checks and simplifies most of the
callers.
I previously removed the code in ValueObject::GetExpressionPath that
took advantage of the parameter `qualify_cxx_base_classes`. As a result,
this is now unused and can be removed.
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:
Adds support for doing range-based for-loops on LLDB's VariableList and
modernises all the index-based for-loops in LLDB where possible.
Reviewers: labath, jdoerfert
Reviewed By: labath
Subscribers: JDevlieghere, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D70668
Summary:
Update StackFrame::GetSymbolContext to mirror the logic in
RegisterContextLLDB::InitializeNonZerothFrame that knows not to do the
pc decrement when the given frame is a signal trap handler frame or the
parent of one, because the pc may not follow a call in these frames.
Accomplish this by adding a behaves_like_zeroth_frame field to
lldb_private::StackFrame, set to true for the zeroth frame, for
signal handler frames, and for parents of signal handler frames.
Also add logic to propagate the signal handler flag from UnwindPlan to
the FrameType on the RegisterContextLLDB it generates, and factor out a
helper to resolve symbol and address range for an Address now that we
need to invoke it in four places.
Reviewers: jasonmolenda, clayborg, jfb
Reviewed By: jasonmolenda
Subscribers: labath, dexonsmith, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D64993
llvm-svn: 367691
Summary:
This commit achieves the following:
- Functions used to return a `TypeSystem *` return an
`llvm::Expected<TypeSystem *>` now. This means that the result of a call
is always checked, forcing clients to move more carefully.
- `TypeSystemMap::GetTypeSystemForLanguage` will either return an Error or a
non-null pointer to a TypeSystem.
Reviewers: JDevlieghere, davide, compnerd
Subscribers: jdoerfert, lldb-commits
Differential Revision: https://reviews.llvm.org/D65122
llvm-svn: 367360
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
There was a crash that would happen if an IDE would ask for a child of a shared pointer via any SB API call that ends up calling StackFrame::GetValueForVariableExpressionPath(). The previous code expects an error to be set describing why the synthetic child of a type was not able to be found, but we have some synthetic child providers that weren't setting the error and returning an empty value object shared pointer. This fixes that to ensure we don't lose our debug session by crashing, fully tests GetValueForVariableExpressionPath functionality, and ensures we don't crash on GetValueForVariableExpressionPath() in the future.
Differential Revision: https://reviews.llvm.org/D59200
llvm-svn: 355850
Unlike std::make_unique, which is only available since C++14,
std::make_shared is available since C++11. Not only is std::make_shared
a lot more readable compared to ::reset(new), it also performs a single
heap allocation for the object and control block.
Differential revision: https://reviews.llvm.org/D57990
llvm-svn: 353764
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
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 patch introduces a concept of "frame recognizer" and "recognized frame". This should be an extensible mechanism that retrieves information about special frames based on ABI, arguments or other special properties of that frame, even without source code. A few examples where that could be useful could be 1) objc_exception_throw, where we'd like to get the current exception, 2) terminate_with_reason and extracting the current terminate string, 3) recognizing Objective-C frames and automatically extracting the receiver+selector, or perhaps all arguments (based on selector).
Differential Revision: https://reviews.llvm.org/D44603
llvm-svn: 345693
This patch introduces a concept of "frame recognizer" and "recognized frame". This should be an extensible mechanism that retrieves information about special frames based on ABI, arguments or other special properties of that frame, even without source code. A few examples where that could be useful could be 1) objc_exception_throw, where we'd like to get the current exception, 2) terminate_with_reason and extracting the current terminate string, 3) recognizing Objective-C frames and automatically extracting the receiver+selector, or perhaps all arguments (based on selector).
Differential Revision: https://reviews.llvm.org/D44603
llvm-svn: 345686
This patch introduces a concept of "frame recognizer" and "recognized frame". This should be an extensible mechanism that retrieves information about special frames based on ABI, arguments or other special properties of that frame, even without source code. A few examples where that could be useful could be 1) objc_exception_throw, where we'd like to get the current exception, 2) terminate_with_reason and extracting the current terminate string, 3) recognizing Objective-C frames and automatically extracting the receiver+selector, or perhaps all arguments (based on selector).
Differential Revision: https://reviews.llvm.org/D44603
llvm-svn: 345678
When we get the `resolve_scope` parameter from the SB API, it's a
`uint32_t`. We then pass it through all of LLDB this way, as a uint32.
This is unfortunate, because it means the user of an API never actually
knows what they're dealing with. We can call it something like
`resolve_scope` and have comments saying "this is a value from the
`SymbolContextItem` enumeration, but it makes more sense to just have it
actually *be* the correct type in the actual C++ type system to begin
with. This way the person reading the code just knows what it is.
The reason to use integers instead of enumerations for flags is because
when you do bitwise operations on enumerations they get promoted to
integers, so it makes it tedious to constantly be casting them back
to the enumeration types, so I've introduced a macro to make this
happen magically. By writing LLDB_MARK_AS_BITMASK_ENUM after defining
an enumeration, it will define overloaded operators so that the
returned type will be the original enum. This should address all
the mechanical issues surrounding using rich enum types directly.
This way, we get a better debugger experience, and new users to
the codebase can get more easily acquainted with the codebase because
their IDE features can help them understand what the types mean.
Differential Revision: https://reviews.llvm.org/D53597
llvm-svn: 345313
This patch teaches lldb to detect when there are missing frames in a
backtrace due to a sequence of tail calls, and to fill in the backtrace
with artificial tail call frames when this happens. This is only done
when the execution history can be determined from the call graph and
from the return PC addresses of calls on the stack. Ambiguous sequences
of tail calls (e.g anything involving tail calls and recursion) are
detected and ignored.
Depends on D49887.
Differential Revision: https://reviews.llvm.org/D50478
llvm-svn: 343900
These three classes have no external dependencies, but they are used
from various low-level APIs. Moving them down to Utility improves
overall code layering (although it still does not break any particular
dependency completely).
The XCode project will need to be updated after this change.
Differential Revision: https://reviews.llvm.org/D49740
llvm-svn: 339127
Adrian Prantl