The ValueObjectConstResult classes that back expression result variables
play a complicated game with where the data for their values is stored.
They try to make it appear as though they are still tied to the memory
in the target into which their value was written when the expression is
run, but they also keep a copy in the Host which they use after the
value is made (expression results are "history values" so that's how we
make sure they have "the value at the time of the expression".)
However, that means that if you ask them to cast themselves to a value
bigger than their original size, they don't have a way to get more
memory for that purpose. The same thing is true of ValueObjects backed
by DataExtractors, the data extractors don't know how to get more data
than they were made with in general.
The only place where we actually ask ValueObjects to sample outside
their captured bounds is when you do ValueObject::Cast from one
structure type to a bigger structure type. In
https://reviews.llvm.org/D153657 I handled this by just disallowing
casts from one structure value to a larger one. My reasoning at the time
was that the use case for this was to support discriminator based C
inheritance schemes, and you can't directly cast values in C, only
pointers, so this was not a natural way to handle those types. It seemed
logical that since you would have had to start with pointers in the
implementation, that's how you would write your lldb introspection code
as well.
Famous last words...
Turns out there are some heavy users of the SB API's who were relying on
this working, and this is a behavior change, so this patch makes this
work in the cases where it used to work before, while still disallowing
the cases we don't know how to support.
Note that if you had done this Cast operation before with either
expression results or value objects from data extractors, lldb would not
have returned the correct results, so the cases this patch outlaws are
ones that actually produce invalid results. So nobody should be using
Cast in these cases, or if they were, this patch will point out the bug
they hadn't yet noticed.
Change GetNumChildren()/CalculateNumChildren() methods return
llvm::Expected
This is an NFC change that does not yet add any error handling or change
any code to return any errors.
This is the second big change in the patch series started with
https://github.com/llvm/llvm-project/pull/83501
A follow-up PR will wire up error handling.
Change GetNumChildren()/CalculateNumChildren() methods return
llvm::Expected
This is an NFC change that does not yet add any error handling or change
any code to return any errors.
This is the second big change in the patch series started with
https://github.com/llvm/llvm-project/pull/83501
A follow-up PR will wire up error handling.
Adds a comment to indicate intention of a piece of value printing code.
I was initially surprised to see this code (distilled for emphasis):
```cpp
if (str.empty()) {
if (style == eValueObjectRepresentationStyleValue)
str = GetSummaryAsCString();
else if (style == eValueObjectRepresentationStyleSummary)
str = GetValueAsCString();
}
```
My first thought was "is this a bug?", but I realized it was likely intentional. This
change adds a comment to indicate yes, this is intentional.
I get a small but fairly steady stream of crash reports which I can only
explain by ValueObjectPrinter trying to access its m_valobj field, and
finding it NULL. I have never been able to reproduce any of these, and
the reports show a state too long after the fact to know what went
wrong.
I've read through this section of lldb a bunch of times trying to figure
out how this could happen, but haven't ever found anything actually
wrong that could cause this. OTOH, ValueObjectPrinter is somewhat sloppy
about how it handles the ValueObject it is printing.
a) lldb allows you to make a ValueObjectPrinter with a Null incoming
ValueObject. However, there's no affordance to set the ValueObject in
the Printer after the fact, and it doesn't really make sense to do that.
So I change the ValueObjectPrinter API's to take a ValueObject
reference, rather than a pointer. All the places that make
ValueObjectPrinters already check the non-null status of their
ValueObject's before making the ValueObjectPrinter, so sadly, I didn't
find the bug, but this will enforce the intent.
b) The next step in printing the ValueObject is deciding which of the
associated DynamicValue/SyntheticValue we are actually printing (based
on the use_dynamic and use_synthetic settings in the original
ValueObject. This was put in a pointer by GetMostSpecializedValue, but
most of the printer code just accessed the pointer, and it was hard to
reason out whether we were guaranteed to always call this before using
m_valobj. So far as I could see we always do (sigh, didn't find the bug
there either) but this was way too hard to reason about.
In fact, we figure out once which ValueObject we're going to print and
don't change that through the life of the printer. So I changed this to
both set the "most specialized value" in the constructor, and then to
always access it through GetMostSpecializedValue(). That makes it easier
to reason about the use of this ValueObject as well.
This is an NFC change, all it does is make the code easier to reason
about.
This reverts commit d657519838 as it
breaks two dozen tests. The breakages are related to variable path
expression parsing and summary string parsing (possibly the same code).
As I worked through changes to another PR
(https://github.com/llvm/llvm-project/pull/74912), I couldn't help but
rewrite a few methods for readability, maintainability, and possibly
some behavior correctness too.
1. Exiting early instead of nested `if`-statements, which:
- Reduces indentation levels for all subsequent lines
- Treats missing pre-conditions similar to an error
- Clearly indicates that the full length of the method is the "happy
path".
2. Explicitly return empty Value Object shared pointers for those error
(like) situations, which
- Reduces the time it takes a maintainer to figure out what the method
actually returns based on those conditions.
3. Converting a mix of `if` and `if`-`else`-statements around an enum
into one `switch` statement, which:
- Consolidates the former branching logic
- Lets the compiler warn you of a (future) missing enum case
- This one may actually change behavior slightly, because what was an
early test for one enum case, now happens later on in the `switch`.
4. Consolidating near-identical, "copy-pasta" logic into one place,
which:
- Separates the common code to the diverging paths.
- Highlights the differences between the code paths.
rdar://119833526
We only ever call this function once, without relying on the defaulted
`honor_array` parameter, so make it non-defaulted. Also `max_length` is
always set to `0`, so remove it entirely.
This simplifies some upcoming refactoring.
This a follow-up PR from this other one:
https://github.com/llvm/llvm-project/pull/74413
Nothing calls into these two methods, so we (@DavidSpickett,
@adrian-prantl, and I) agreed to remove them once we merged the previous
PR.
This patch replaces uses of StringRef::{starts,ends}with with
StringRef::{starts,ends}_with for consistency with
std::{string,string_view}::{starts,ends}_with in C++20.
I'm planning to deprecate and eventually remove
StringRef::{starts,ends}with.
It's more meaningful and actionable to indicate which element in the
array has an issue by returning that element's index instead of its
value. The value can be ambiguous if at least one other element has the
same value.
The first parameter for these methods is `idxs`, an array of indices
that represent a path from a (root) parent to on of its descendants,
typically though intermediate descendants. When the path leads to a
descendant that doesn't exist, the method is supposed to indicate where
things went wrong by setting an index to `&index_of_error`, the second
parameter.
The problem is the method sets `*index_of_error` to the index of the
most recent parent's child in the hierarchy, which isn't very useful if
there's more one index with the same value in the path.
In this example, each element in the path has a value that's the same as
another element.
```cpp
GetChildAtIndexPath({1, 2, 3, 3, 1, 1, 2}, &index_of_error);
```
Say the the second `1` in the path (the 5th element at `[4]`) doesn't
exist and the code returns a `nullptr`. In that situation, the code sets
`*index_of_error` to `1`, but that's an ambiguous hint can implicate the
1st, 5th, or 6th element (at `[0]`, `[4]`, or `[5]`).
It’s more helpful to set `*index_of_error` to `4` to clearly indicate
which element in `idxs` has the issue.
I received a couple of nullptr-deref crash reports with no line numbers
in this function. The way the function was written it was a bit
diffucult to keep track of when result_sp could be null, so this patch
simplifies the function to make it more obvious when a nullptr can be
contained in the variable.
Add the ability to get a C++ vtable ValueObject from another
ValueObject.
This patch adds the ability to ask a ValueObject for a ValueObject that
represents the virtual function table for a C++ class. If the
ValueObject is not a C++ class with a vtable, a valid ValueObject value
will be returned that contains an appropriate error. If it is successful
a valid ValueObject that represents vtable will be returned. The
ValueObject that is returned will have a name that matches the demangled
value for a C++ vtable mangled name like "vtable for <class-name>". It
will have N children, one for each virtual function pointer. Each
child's value is the function pointer itself, the summary is the
symbolication of this function pointer, and the type will be a valid
function pointer from the debug info if there is debug information
corresponding to the virtual function pointer.
The vtable SBValue will have the following:
- SBValue::GetName() returns "vtable for <class>"
- SBValue::GetValue() returns a string representation of the vtable
address
- SBValue::GetSummary() returns NULL
- SBValue::GetType() returns a type appropriate for a uintptr_t type for
the current process
- SBValue::GetLoadAddress() returns the address of the vtable adderess
- SBValue::GetValueAsUnsigned(...) returns the vtable address
- SBValue::GetNumChildren() returns the number of virtual function
pointers in the vtable
- SBValue::GetChildAtIndex(...) returns a SBValue that represents a
virtual function pointer
The child SBValue objects that represent a virtual function pointer has
the following values:
- SBValue::GetName() returns "[%u]" where %u is the vtable function
pointer index
- SBValue::GetValue() returns a string representation of the virtual
function pointer
- SBValue::GetSummary() returns a symbolicated respresentation of the
virtual function pointer
- SBValue::GetType() returns the function prototype type if there is
debug info, or a generic funtion prototype if there is no debug info
- SBValue::GetLoadAddress() returns the address of the virtual function
pointer
- SBValue::GetValueAsUnsigned(...) returns the virtual function pointer
- SBValue::GetNumChildren() returns 0
- SBValue::GetChildAtIndex(...) returns invalid SBValue for any index
Examples of using this API via python:
```
(lldb) script vtable = lldb.frame.FindVariable("shape_ptr").GetVTable()
(lldb) script vtable
vtable for Shape = 0x0000000100004088 {
[0] = 0x0000000100003d20 a.out`Shape::~Shape() at main.cpp:3
[1] = 0x0000000100003e4c a.out`Shape::~Shape() at main.cpp:3
[2] = 0x0000000100003e7c a.out`Shape::area() at main.cpp:4
[3] = 0x0000000100003e3c a.out`Shape::optional() at main.cpp:7
}
(lldb) script c = vtable.GetChildAtIndex(0)
(lldb) script c
(void ()) [0] = 0x0000000100003d20 a.out`Shape::~Shape() at main.cpp:3
```
Value::ResolveValue calls Value::GetValueAsData as part of its
implementation. The latter can receive an optional Module pointer, which
is always null when called from the former. Allow threading in the
Module in Value::ResolveValue.
rdar://115021869
- Allow the definition of synthetic formatters in C++ even when LLDB is built without python scripting support.
- Fix linking problems with the CXXSyntheticChildren
Differential Revision: https://reviews.llvm.org/D158010
Existing callers of `GetChildAtIndex` pass true for can_create. This change
makes true the default value, callers don't have to pass an opaque true.
See also D151966 for the same change to `GetChildMemberWithName`.
Differential Revision: https://reviews.llvm.org/D152031
It turns out all existing callers of `GetChildMemberWithName` pass true for `can_create`.
This change makes `true` the default value, callers don't have to pass an opaque true.
Differential Revision: https://reviews.llvm.org/D151966
Following D151810, this changes `GetChildAtNamePath` to take a path of `StringRef`
values instead of `ConstString`.
Differential Revision: https://reviews.llvm.org/D151813
As with D151615, which changed `GetIndexOfChildMemberWithName` to take a `StringRef`
instead of a `ConstString`, this change does the same for `GetIndexOfChildWithName`.
Differential Revision: https://reviews.llvm.org/D151811
`GetChildMemberWithName` does not need a `ConstString`. This change makes the function
take a `StringRef` instead, which alleviates the need for callers to construct a
`ConstString`. I don't expect this change to improve performance, only ergonomics.
This is in support of Alex's effort to replace `ConstString` where appropriate.
There are related `ValueObject` functions that can also be changed, if this is accepted.
Differential Revision: https://reviews.llvm.org/D151615
This is a user facing action, it is meant to focus the user's attention on
something other than the 0th frame when you stop somewhere where that's
helpful. For instance, stopping in pthread_kill after an assert will select
the assert frame.
This is not something you want to have happen internally in lldb, both
because internally you really don't want the selected frame changing out
from under you, and because the recognizers can do arbitrary work, and that
can cause deadlocks or other unexpected behavior.
However, it's not something that the current code does
explicitly after a stop has been delivered, it's expected to happen implicitly
as part of stopping. I changing this to call SMRF explicitly after a user
stop, but that got pretty ugly quickly.
So I added a bool to control whether to run this and audited all the current
uses to determine whether we're returning to the user or not.
Differential Revision: https://reviews.llvm.org/D148863
We used to make a dynamic value that "pretended to be its parent"
but that's hard for some of the more complex ValueObject types, and
it's better in this case just to return no dynamic value.
Differential Revision: https://reviews.llvm.org/D145629
Reverting because Xcode requires this to be handled elsewhere.
The global variable list gets constructed using the SBAPI
This reverts commit de10c1a824.
Revert while I investigate two CI bot failures;
the more important is the lldb-arm-ubuntu where
the FixAddress is removing the 0th bit so we're
adding the `actual=` decorator on a string pointer,
```
Got output:
(char *) strptr = 0x00400817 (actual=0x400816) ptr = [{ },{H}]
```
in TestDataFormatterSmartArray.py line 229.
This reverts commit 4d635be2db.
On target where metadata is stored in bits that aren't used for
virtual addressing -- AArch64 Top Byte Ignore and pointer authentication
are two examples -- an SBValue object representing a pointer will
return the address with metadata for SBValue::GetValueAsUnsigned.
Users may want to get the virtual address without the metadata;
this new method gives them a way to do this.
Differential Revision: https://reviews.llvm.org/D142792
hold an error should:
(a) return false for IsValid, since that's the current behavior and is
a convenient way to check "should I get the value for this".
(b) preserve the error when an SBValue is made from it, and print the
error in the ValueObjectPrinter.
Make that happen.
Differential Revision: https://reviews.llvm.org/D144664
-flimit-debug-info and other compiler options might end up removing debug info that is needed for debugging. LLDB marks these types as being forcefully completed in the metadata in the TypeSystem. These types should have been complete in the debug info but were not because the compiler omitted them to save space. When we can't find a suitable replacement for the type, we should let the user know that these types are incomplete to indicate there was an issue instead of just showing nothing for a type.
The solution is to display presented in this patch is to display "<incomplete type>" as the summary for any incomplete types. If there is a summary string or function that is provided for a type, but the type is currently forcefully completed, the installed summary will be ignored and we will display "<incomplete type>". This patch also exposes the ability to ask a SBType if it was forcefully completed with:
bool SBType::IsTypeForcefullyCompleted();
This will allow the user interface for a debugger to also detect this issue and possibly mark the variable display up on some way to indicate to the user the type is incomplete.
To show how this is diplayed, we can look at the existing output first for the example source file from the file: lldb/test/API/functionalities/limit-debug-info/main.cpp
(lldb) frame variable inherits_from_one inherits_from_two one_as_member two_as_member array_of_one array_of_two shadowed_one
(InheritsFromOne) ::inherits_from_one = (member = 47)
(InheritsFromTwo) ::inherits_from_two = (member = 47)
(OneAsMember) ::one_as_member = (one = member::One @ 0x0000000100008028, member = 47)
(TwoAsMember) ::two_as_member = (two = member::Two @ 0x0000000100008040, member = 47)
(array::One [3]) ::array_of_one = ([0] = array::One @ 0x0000000100008068, [1] = array::One @ 0x0000000100008069, [2] = array::One @ 0x000000010000806a)
(array::Two [3]) ::array_of_two = ([0] = array::Two @ 0x0000000100008098, [1] = array::Two @ 0x0000000100008099, [2] = array::Two @ 0x000000010000809a)
(ShadowedOne) ::shadowed_one = (member = 47)
(lldb) frame variable --show-types inherits_from_one inherits_from_two one_as_member two_as_member array_of_one array_of_two shadowed_one
(InheritsFromOne) ::inherits_from_one = {
(int) member = 47
}
(InheritsFromTwo) ::inherits_from_two = {
(int) member = 47
}
(OneAsMember) ::one_as_member = {
(member::One) one = {}
(int) member = 47
}
(TwoAsMember) ::two_as_member = {
(member::Two) two = {}
(int) member = 47
}
(array::One [3]) ::array_of_one = {
(array::One) [0] = {}
(array::One) [1] = {}
(array::One) [2] = {}
}
(array::Two [3]) ::array_of_two = {
(array::Two) [0] = {}
(array::Two) [1] = {}
(array::Two) [2] = {}
}
(ShadowedOne) ::shadowed_one = {
(int) member = 47
}
With this patch in place we can now see any classes that were forcefully completed to let us know that we are missing information:
(lldb) frame variable inherits_from_one inherits_from_two one_as_member two_as_member array_of_one array_of_two shadowed_one
(InheritsFromOne) ::inherits_from_one = (One = <incomplete type>, member = 47)
(InheritsFromTwo) ::inherits_from_two = (Two = <incomplete type>, member = 47)
(OneAsMember) ::one_as_member = (one = <incomplete type>, member = 47)
(TwoAsMember) ::two_as_member = (two = <incomplete type>, member = 47)
(array::One[3]) ::array_of_one = ([0] = <incomplete type>, [1] = <incomplete type>, [2] = <incomplete type>)
(array::Two[3]) ::array_of_two = ([0] = <incomplete type>, [1] = <incomplete type>, [2] = <incomplete type>)
(ShadowedOne) ::shadowed_one = (func_shadow::One = <incomplete type>, member = 47)
(lldb) frame variable --show-types inherits_from_one inherits_from_two one_as_member two_as_member array_of_one array_of_two shadowed_one
(InheritsFromOne) ::inherits_from_one = {
(One) One = <incomplete type> {}
(int) member = 47
}
(InheritsFromTwo) ::inherits_from_two = {
(Two) Two = <incomplete type> {}
(int) member = 47
}
(OneAsMember) ::one_as_member = {
(member::One) one = <incomplete type> {}
(int) member = 47
}
(TwoAsMember) ::two_as_member = {
(member::Two) two = <incomplete type> {}
(int) member = 47
}
(array::One[3]) ::array_of_one = {
(array::One) [0] = <incomplete type> {}
(array::One) [1] = <incomplete type> {}
(array::One) [2] = <incomplete type> {}
}
(array::Two[3]) ::array_of_two = {
(array::Two) [0] = <incomplete type> {}
(array::Two) [1] = <incomplete type> {}
(array::Two) [2] = <incomplete type> {}
}
(ShadowedOne) ::shadowed_one = {
(func_shadow::One) func_shadow::One = <incomplete type> {}
(int) member = 47
}
Differential Revision: https://reviews.llvm.org/D138259
After D134378, we started seeing crashes with incomplete types (in the
context of shared libraries).
When trying to print a `std::vector<int> &` with only debug info for a
declaration, we now try to use the formatter after D134378. With an
incomplete type, this somehow goes into infinite recursion with the
frames
```
lldb_private::ValueObject::Dereference
lldb_private::ValueObjectSynthetic::CreateSynthFilter
lldb_private::ValueObjectSynthetic::ValueObjectSynthetic
lldb_private::ValueObject::CalculateSyntheticValue
lldb_private::ValueObject::HasSyntheticValue
```
This has to do with `FrontEndWantsDereference` that some STL formatters
set, causing recursion between the formatter (which tries to dereference),
and dereferencing (which wants to know if there's a formatter to avoid dereferencing).
The reason this only started appearing after D134378 was because
previously with incomplete types, for names with `<`, lldb would attempt
to parse template parameter DIEs, which were empty, then create an empty
`ClassTemplateSpecializationDecl` which overrode the name used to lookup
a formatter in `FormattersMatchData()` to not include template
parameters (e.g. `std::vector<> &`). After D134378 we don't create a
`ClassTemplateSpecializationDecl` when there are no template parameters
and the name to lookup a formatter is the original name (e.g.
`std::vector<int> &`).
The code to try harder with incomplete child compiler types was added in
D79554 for ObjC purposes.
Reviewed By: labath
Differential Revision: https://reviews.llvm.org/D137983
This reverts commit 0205aa4a02 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
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
Currently, all data buffers are assumed to be writable. This is a
problem on macOS where it's not allowed to load unsigned binaries in
memory as writable. To be more precise, MAP_RESILIENT_CODESIGN and
MAP_RESILIENT_MEDIA need to be set for mapped (unsigned) binaries on our
platform.
Binaries are mapped through FileSystem::CreateDataBuffer which returns a
DataBufferLLVM. The latter is backed by a llvm::WritableMemoryBuffer
because every DataBuffer in LLDB is considered to be writable. In order
to use a read-only llvm::MemoryBuffer I had to split our abstraction
around it.
This patch distinguishes between a DataBuffer (read-only) and
WritableDataBuffer (read-write) and updates LLDB to use the appropriate
one.
rdar://74890607
Differential revision: https://reviews.llvm.org/D122856
Applied modernize-use-default-member-init clang-tidy check over LLDB.
It appears in many files we had already switched to in class member init but
never updated the constructors to reflect that. This check is already present in
the lldb/.clang-tidy config.
Differential Revision: https://reviews.llvm.org/D121481
Embedded nul characters are still printed, and they don't terminate the
string. See also D111634.
Differential Revision: https://reviews.llvm.org/D120803
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.
