This patch adds a new matching method for data formatters, in addition
to the existing exact typename and regex-based matching. The new method
allows users to specify the name of a Python callback function that
takes a `SBType` object and decides whether the type is a match or not.
Here is an overview of the changes performed:
- Add a new `eFormatterMatchCallback` matching type, and logic to handle
it in `TypeMatcher` and `SBTypeNameSpecifier`.
- Extend `FormattersMatchCandidate` instances with a pointer to the
current `ScriptInterpreter` and the `TypeImpl` corresponding to the
candidate type, so we can run registered callbacks and pass the type
to them. All matcher search functions now receive a
`FormattersMatchCandidate` instead of a type name.
- Add some glue code to ScriptInterpreterPython and the SWIG bindings to
allow calling a formatter matching callback. Most of this code is
modeled after the equivalent code for watchpoint callback functions.
- Add an API test for the new callback-based matching feature.
For more context, please check the RFC thread where this feature was
originally discussed:
https://discourse.llvm.org/t/rfc-python-callback-for-data-formatters-type-matching/64204/11
Differential Revision: https://reviews.llvm.org/D135648
The main aim of this patch is to delete the remaining instances of code
reaching into the internals of `TypeCategoryImpl`. I made the following
changes:
- Add some more methods to `TieredFormatterContainer` and
`TypeCategoryImpl` to expose functionality that is implemented in
`FormattersContainer`.
- Add new overloads of `TypeCategoryImpl::AddTypeXXX` to make it easier
to add formatters to categories without reaching into the internal
`FormattersContainer` objects.
- Remove the `GetTypeXXXContainer` and `GetRegexTypeXXXContainer`
accessors from `TypeCategoryImpl` and update all call sites to use the
new methods instead.
Differential Revision: https://reviews.llvm.org/D135399
`FormatterContainerPair` is (as its name indicates) a very thin wrapper
over two formatter containers, one for exact matches and another one for
regex matches. The logic to decide which subcontainer to access is
replicated everywhere `FormatterContainerPair`s are used.
So, for example, when we look for a formatter there's some adhoc code
that does a lookup in the exact match formatter container, and if it
fails it does a lookup in the regex match formatter container. The same
logic is then copied and pasted for summaries, filters, and synthetic
child providers.
This change introduces a new `TieredFormatterContainer` that has two
main characteristics:
- It generalizes `FormatterContainerPair` from 2 to any number of
subcontainers, that are looked up in priority order.
- It centralizes all the logic to choose which subcontainer to use for
lookups, add/delete, and indexing.
This allows us to have a single copy of the same logic, templatized for
each kind of formatter. It also simplifies the upcoming addition of a
new tier of callback-based matches. See
https://discourse.llvm.org/t/rfc-python-callback-for-data-formatters-type-matching/64204
for more details about this.
The rest of the change is mostly replacing copy-pasted code with calls
to methods of the relevant `TieredFormatterContainer`, and adding some
methods to the `TypeCategoryImpl` class so we can remove some of this
copy-pasted code from `SBTypeCategory`.
Differential Revision: https://reviews.llvm.org/D133910
- Merge pairs like `eFormatCategoryItemSummary` and
`eFormatCategoryItemRegexSummary` into a single value. See explanation
below.
- Rename `eFormatCategoryItemValue` to `eFormatCategoryItemFormat`. This
makes the enum match the names used elsewhere for formatter kinds
(format, summary, filter, synth).
- Delete unused values `eFormatCategoryItemValidator` and
`eFormatCategoryItemRegexValidator`.
This enum is only used to reuse some code in CommandObjectType.cpp. For
example, instead of having separate implementations for `type summary
delete`, `type format delete`, and so on, there's a single generic
implementation that takes an enum value, and then the specific commands
derive from it and set the right flags for the specific kind of
formatter.
Even though the enum distinguishes between regular and regex matches for
every kind of formatter, this distinction is never used: enum values are
always specified in pairs like
`eFormatCategoryItemSummary | eFormatCategoryItemRegexSummary`.
This causes some ugly code duplication in TypeCategory.cpp. In order to
handle every flag combination some code appears 8 times:
{format, summary, synth, filter} x {exact, regex}
Differential Revision: https://reviews.llvm.org/D134244
LLVM contains a helpful function for getting the size of a C-style
array: `llvm::array_lengthof`. This is useful prior to C++17, but not as
helpful for C++17 or later: `std::size` already has support for C-style
arrays.
Change call sites to use `std::size` instead.
Differential Revision: https://reviews.llvm.org/D133501
This removes some error-prone repetition in
FormatManager::GetPossibleMatches, where the same three boolean flags
are passed in a row multiple times as arguments to recursive calls to
GetPossibleMatches.
Instead of:
```
// same flags, but with did_strip_typedef set to true.
GetPossibleMatches(..., did_strip_ptr, did_strip_ref, true);
```
we can now say
```
GetPossibleMatches(..., current_flags.WithStrippedTypedef());
```
which hopefully makes the intent clearer, and more readable in case we
add another flag.
Reviewed by: DavidSpickett, labath
Differential Revision: https://reviews.llvm.org/D131459
This adds a setting (`target.max-children-depth`) that will provide a default value for the `--depth` flag used by `expression` and `frame variable`.
The new setting uses the same default that's currently fixed in source: `UINT32_MAX`.
This provides two purposes:
1. Allowing downstream forks to provide a customized default.
2. Allowing users to set their own default.
Following `target.max-children-count`, a warning is emitted when the max depth is reached. The warning lets users know which flags or settings they can customize. This warning is shown only when the limit is the default value.
rdar://87466495
Differential Revision: https://reviews.llvm.org/D123954
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
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 reverts commit ef82063207.
- It conflicts with the existing llvm::size in STLExtras, which will now
never be called.
- Calling it without llvm:: breaks C++17 compat
They were being applied too narrowly (they didn't cover signed char *,
for instance), and too broadly (they covered SomeTemplate<char[6]>) at
the same time.
Differential Revision: https://reviews.llvm.org/D112709
With arm64e ARMv8.3 pointer authentication, lldb needs to know how
many bits are used for addressing and how many are used for pointer
auth signing. This should be determined dynamically from the inferior
system / corefile, but there are some workflows where it still isn't
recorded and we fall back on a default value that is correct on some
Darwin environments.
This patch also explicitly sets the vendor of mach-o binaries to
Apple, so we select an Apple ABI instead of a random other ABI.
It adds a function pointer formatter for systems where pointer
authentication is in use, and we can strip the ptrauth bits off
of the function pointer address and get a different value that
points to an actual symbol.
Differential Revision: https://reviews.llvm.org/D115431
rdar://84644661
The StringPrinter class was using a Process instance to read memory.
This automatically prevented it from working before starting the
program.
This patch changes the class to use the Target object for reading
memory, as targets are always available. This required moving
ReadStringFromMemory from Process to Target.
This is sufficient to make frame/target variable work, but further
changes are necessary for the expression evaluator. Preliminary analysis
indicates the failures are due to the expression result ValueObjects
failing to provide an address, presumably because we're operating on
file addresses before starting. I haven't looked into what would it take
to make that work.
Differential Revision: https://reviews.llvm.org/D113098
This patch changes the string summaries for vector types by removing the
space between the type and the bracket, conforming to 277623f4d5.
This should also fix TestCompactVectors failure.
Differential Revision: https://reviews.llvm.org/D112340
Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
Based on post-commit review discussion on
2bd8493847 with Richard Smith.
Other uses of forcing HasEmptyPlaceHolder to false seem OK to me -
they're all around pointer/reference types where the pointer/reference
token will appear at the rightmost side of the left side of the type
name, so they make nested types (eg: the "int" in "int *") behave as
though there is a non-empty placeholder (because the "*" is essentially
the placeholder as far as the "int" is concerned).
This was originally committed in 277623f4d5
Reverted in f9ad1d1c77 due to breakages
outside of clang - lldb seems to have some strange/strong dependence on
"char [N]" versus "char[N]" when printing strings (not due to that name
appearing in DWARF, but probably due to using clang to stringify type
names) that'll need to be addressed, plus a few other odds and ends in
other subprojects (clang-tools-extra, compiler-rt, etc).
lldb_private::DataExtractor contains DataBufferSP m_data_sp which is
relatively expensive to copy (due to multi-threading locking).
llvm::DataExtractor does not have this problem as it uses StringRef
instead.
The copy constructor is explicit as otherwise it is easy to make
unintended modification of a local copy instead of a caller's instance
(D107470 but that is llvm::DataExtractor).
Reviewed By: clayborg
Differential Revision: https://reviews.llvm.org/D107485
This converts a default constructor's member initializers into C++11
default member initializers. This patch was automatically generated with
clang-tidy and the modernize-use-default-member-init check.
$ run-clang-tidy.py -header-filter='lldb' -checks='-*,modernize-use-default-member-init' -fix
This is a mass-refactoring patch and this commit will be added to
.git-blame-ignore-revs.
Differential revision: https://reviews.llvm.org/D103483
The C headers are deprecated so as requested in D102845, this is replacing them
all with their (not deprecated) C++ equivalent.
Reviewed By: shafik
Differential Revision: https://reviews.llvm.org/D103084
ValueObject inherits from UserID which is just a bad idea:
* The inheritance gives ValueObject some member functions that are at best
misleading (such as `Clear()` which doesn't clear any value beside `id`).
* It allows passing ValueObject to the overloaded operators for UserID (such as
`==` or `<<` which won't actually compare or print anything in the ValueObject).
* It exposes the `SetID` and `Clear` which both allow users to change the
internal id value.
Similar to D91699 which did the same for Process
Reviewed By: #lldb, JDevlieghere
Differential Revision: https://reviews.llvm.org/D97205
The comment for ValueType claims that all values <1 are errors, but
not all switch statements take this into account. This patch
introduces an explicit Error case and deletes all default: cases, so
we get warned about incomplete switch coverage.
https://reviews.llvm.org/D96537
Several data formatters assume their types are in the Target's scratch AST and
build new types from that scratch AST instance. However, types from different
ASTs shouldn't be mixed, so this (unchecked) assumption may lead to problems if
we ever have more than one scratch AST or someone somehow invokes data
formatters on a type that are not in the scratch AST.
Instead we can use in all the formatters just the TypeSystem of the type we're
formatting. That's much simpler and avoids all the headache of finding the right
TypeSystem that matches the one of the formatted type.
Right now LLDB only has one scratch TypeSystemClang instance and we format only
types that are in the scratch AST, so this doesn't change anything in the
current way LLDB works. The intention here is to allow follow up refactorings
that introduce multiple scratch ASTs with the same Target.
Differential Revision: https://reviews.llvm.org/D92757
Display null pointer as `nullptr`, `nil` and `NULL` for C++,
Objective-C/Objective-C++ and C respectively. The original motivation
for this patch was to display a null std::string pointer as nullptr
instead of "", but the fix seemed generic enough to be done for all
summary providers.
Differential revision: https://reviews.llvm.org/D77153
Summary:
FormattersContainer.h has two containers: FormatMap and FormattersContainer
itself. FormatMap is essentially just a SetVector with a listener interface that
is aspiring to be thread-safe as most of its functions lock its member mutex.
FormattersContainer is for the most part just calling the matching functions of
internal FormatMap instance and essentially acts as a wrapper class with some
minor formatter search functionality on top. The only difference is that the
FormattersContainer's public `Get` function is actually searching formatters in
the list of formatters (and for example doing regex-matching) while FormatMap's
`Get` function is just looking up a a format by the type matcher string.
This patch deletes `FormatMap` by just renaming it to `FormattersContainer` and
pulling in the two `Get` functions from the original `FormattersContainer`
class.
The only other user of `FormatMap` was the `NamedSummariesMap` in the
`FormatManager` which I migrated by just making it also a `FormattersContainer`
and replaced the only call to the `Get` function (which now has new semantics)
with `GetExact` (which is FormattersContainer's function that has the semantics
of FormatMap's `Get`). As `NamedSummariesMap` only stores non-regex-based
formatters, both `Get` and `GetExact` would have worked, so this was mostly to
clarify that this is supposed to be NFC.
I also added the missing mutex lock in the `GetCount` function which was
previously missing in the `FormatMap` implementation. Technically not "NFC" but
I anyway had to change the function...
Reviewers: labath, mib
Reviewed By: labath
Subscribers: abidh, JDevlieghere
Differential Revision: https://reviews.llvm.org/D84296
This was originally reverted because the m_valid member in TypeMatcher was
unused in builds with disabled asserts. Now the member is gone and the default
constructor is deleted (thanks Eric for the idea!).
Summary:
FormattersContainer stores LLDB's formatters. It's implemented as a templated
map-like data structures that supports any kind of value type and only allows
ConstString and RegularExpression as the key types. The keys are used for
matching type names (e.g., the ConstString key `std::vector` matches the type
with the same name while RegularExpression keys match any type where the
RegularExpression instance matches).
The fact that a single FormattersContainer can only match either by string
comparison or regex matching (depending on the KeyType) causes us to always have
two FormatterContainer instances in all the formatting code. This also leads to
us having every type name matching logic in LLDB twice. For example,
TypeCategory has to implement every method twice (one string matching one, one
regex matching one).
This patch changes FormattersContainer to instead have a single `TypeMatcher`
key that wraps the logic for string-based and regex-based type matching and is
now the only possible KeyType for the FormattersContainer. This means that a
single FormattersContainer can now match types with both regex and string
comparison.
To summarize the changes in this patch:
* Remove all the `*_Impl` methods from `FormattersContainer`
* Instead call the FormatMap functions from `FormattersContainer` with a
`TypeMatcher` type that does the respective matching.
* Replace `ConstString` with `TypeMatcher` in the few places that directly
interact with `FormattersContainer`.
I'm working on some follow up patches that I split up because they deserve their
own review:
* Unify FormatMap and FormattersContainer (they are nearly identical now).
* Delete the duplicated half of all the type matching code that can now use one
interface.
* Propagate TypeMatcher through all the formatter code interfaces instead of
always offering two functions for everything.
There is one ugly design part that I couldn't get rid of yet and that is that we
have to support getting back the string used to construct a `TypeMatcher` later
on. The reason for this is that LLDB only supports referencing existing type
matchers by just typing their respective input string again (without even
supplying if it's a regex or not).
Reviewers: davide, mib
Reviewed By: mib
Subscribers: mgorny, JDevlieghere
Differential Revision: https://reviews.llvm.org/D84151
This patch has no effect for C and C++. In more dynamic languages,
such as Objective-C and Swift GetByteSize() needs to call into the
language runtime, so it's important to pass one in where possible. My
primary motivation for this is some work I'm doing on the Swift
branch, however, it looks like we are also seeing warnings in
Objective-C that this may resolve. Everything in the SymbolFile
hierarchy still passes in nullptrs, because we don't have an execution
context in SymbolFile, since SymbolFile transcends processes.
Differential Revision: https://reviews.llvm.org/D84267
This was originally reverted because the Linux bots were red after this landed,
but it seems that was actually caused by a different commit. I double checked
that this works on Linux, so let's reland this on Linux.
Summary:
FormattersContainer stores LLDB's formatters. It's implemented as a templated
map-like data structures that supports any kind of value type and only allows
ConstString and RegularExpression as the key types. The keys are used for
matching type names (e.g., the ConstString key `std::vector` matches the type
with the same name while RegularExpression keys match any type where the
RegularExpression instance matches).
The fact that a single FormattersContainer can only match either by string
comparison or regex matching (depending on the KeyType) causes us to always have
two FormatterContainer instances in all the formatting code. This also leads to
us having every type name matching logic in LLDB twice. For example,
TypeCategory has to implement every method twice (one string matching one, one
regex matching one).
This patch changes FormattersContainer to instead have a single `TypeMatcher`
key that wraps the logic for string-based and regex-based type matching and is
now the only possible KeyType for the FormattersContainer. This means that a
single FormattersContainer can now match types with both regex and string
comparison.
To summarize the changes in this patch:
* Remove all the `*_Impl` methods from `FormattersContainer`
* Instead call the FormatMap functions from `FormattersContainer` with a
`TypeMatcher` type that does the respective matching.
* Replace `ConstString` with `TypeMatcher` in the few places that directly
interact with `FormattersContainer`.
I'm working on some follow up patches that I split up because they deserve their
own review:
* Unify FormatMap and FormattersContainer (they are nearly identical now).
* Delete the duplicated half of all the type matching code that can now use one
interface.
* Propagate TypeMatcher through all the formatter code interfaces instead of
always offering two functions for everything.
There is one ugly design part that I couldn't get rid of yet and that is that we
have to support getting back the string used to construct a `TypeMatcher` later
on. The reason for this is that LLDB only supports referencing existing type
matchers by just typing their respective input string again (without even
supplying if it's a regex or not).
Reviewers: davide, mib
Reviewed By: mib
Subscribers: mgorny, JDevlieghere
Differential Revision: https://reviews.llvm.org/D84151
Summary:
FormattersContainer stores LLDB's formatters. It's implemented as a templated
map-like data structures that supports any kind of value type and only allows
ConstString and RegularExpression as the key types. The keys are used for
matching type names (e.g., the ConstString key `std::vector` matches the type
with the same name while RegularExpression keys match any type where the
RegularExpression instance matches).
The fact that a single FormattersContainer can only match either by string
comparison or regex matching (depending on the KeyType) causes us to always have
two FormatterContainer instances in all the formatting code. This also leads to
us having every type name matching logic in LLDB twice. For example,
TypeCategory has to implement every method twice (one string matching one, one
regex matching one).
This patch changes FormattersContainer to instead have a single `TypeMatcher`
key that wraps the logic for string-based and regex-based type matching and is
now the only possible KeyType for the FormattersContainer. This means that a
single FormattersContainer can now match types with both regex and string
comparison.
To summarize the changes in this patch:
* Remove all the `*_Impl` methods from `FormattersContainer`
* Instead call the FormatMap functions from `FormattersContainer` with a
`TypeMatcher` type that does the respective matching.
* Replace `ConstString` with `TypeMatcher` in the few places that directly
interact with `FormattersContainer`.
I'm working on some follow up patches that I split up because they deserve their
own review:
* Unify FormatMap and FormattersContainer (they are nearly identical now).
* Delete the duplicated half of all the type matching code that can now use one
interface.
* Propagate TypeMatcher through all the formatter code interfaces instead of
always offering two functions for everything.
There is one ugly design part that I couldn't get rid of yet and that is that we
have to support getting back the string used to construct a `TypeMatcher` later
on. The reason for this is that LLDB only supports referencing existing type
matchers by just typing their respective input string again (without even
supplying if it's a regex or not).
Reviewers: davide, mib
Reviewed By: mib
Subscribers: mgorny, JDevlieghere
Differential Revision: https://reviews.llvm.org/D84151
Summary:
FormattersContainer currently has an unused `m_name` member. Usually LLDB allows
giving objects names, but for the FormattersContainer it seems excessive. There
are only 4 FormattersContainer variables in LLDB and they are not usually passed
around, so one can always just go up a few frames when debugging to find out
which FormattersContainer you're dealing with.
Reviewers: mib, davide
Reviewed By: mib
Subscribers: JDevlieghere
Differential Revision: https://reviews.llvm.org/D84154
Support printing strings which contain invalid utf8 sub-sequences, e.g.
strings like "hello world \xfe", instead of bailing out with "Summary
Unavailable".
I took the opportunity here to delete some hand-rolled utf8 -> utf32
conversion code and replace it with calls into llvm's Support library.
rdar://61554346
Summary:
Languages can have different ways of formatting special characters.
E.g. when debugging C++ code a string might look like "\b", but when
debugging Swift code the same string would look like "\u{8}".
To make this work, plugins override GetStringPrinterEscapingHelper.
However, because there's a large amount of subtly divergent work done in
each override, we end up with large amounts of duplicated code. And all
the memory smashers fixed in one copy of the logic (see D73860) don't
get fixed in the others.
IMO the GetStringPrinterEscapingHelper is overly general and hard to
use. I propose deleting it and replacing it with an EscapeStyle enum,
which can be set as needed by each plugin.
A fix for some swift-lldb memory smashers falls out fairly naturally
from this deletion (https://github.com/apple/llvm-project/pull/1046). As
the swift logic becomes really tiny, I propose moving it upstream as
part of this change. I've added unit tests to cover it.
rdar://61419673
Reviewers: JDevlieghere, davide
Subscribers: mgorny, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D77843
Summary:
The formatters code has a lot of 'reason' or 'why' values that we keep or-ing FormatterChoiceCriterion
enum values into. These values are only read by a single log statement and don't have any functional
purpose. It also seems the implementation is not finished (for example, display names and type
names don't have any dedicated enum values). Also everything is of course not tested or documented.
Let's just remove all of this.
Reviewers: labath, JDevlieghere, jingham, davide, vsk
Reviewed By: labath, vsk
Subscribers: JDevlieghere
Differential Revision: https://reviews.llvm.org/D77968
Summary:
These two variables are only incremented under LLDB_CONFIGURATION_DEBUG but their
value is always logged when verbose lldb formatter logging is enabled, which causes that our
cache hit/miss log looks like this in non-Debug builds:
```
Cache hits: 0 - Cache Misses: 0
...
Cache hits: 0 - Cache Misses: 0
...
Cache hits: 0 - Cache Misses: 0
```
This just always increments those two counters independent of build mode.
Reviewers: JDevlieghere
Reviewed By: JDevlieghere
Differential Revision: https://reviews.llvm.org/D76687
This adds a formatter for libc++ std::unique_ptr.
I also refactored GetValueOfCompressedPair(...) out of LibCxxList.cpp since I need the same functionality and it made sense to share it.
Differential Revision: https://reviews.llvm.org/D76476
(This is D68010 but I also set the new parameter in LibStdcpp.cpp to fix
the Debian tests).
Summary:
Printing a summary for an empty NSPathStore2 string currently prints random bytes behind the empty string pointer from memory (rdar://55575888).
It seems the reason for this is that the SourceSize parameter in the `ReadStringAndDumpToStreamOptions` - which is supposed to contain the string
length - actually uses the length 0 as a magic value for saying "read as much as possible from the buffer" which is clearly wrong for empty strings.
This patch adds another flag that indicates if we have know the string length or not and makes this behaviour dependent on that (which seemingly
was the original purpose of this magic value).
Reviewers: aprantl, JDevlieghere, shafik
Reviewed By: aprantl
Subscribers: christof, abidh, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D68010
This reverts commit 939ca455e7.
This failed on the debian bot for some reason:
File "/home/worker/lldb-x86_64-debian/lldb-x86_64-debian/llvm-project/lldb/test/API/functionalities/data-formatter/data-formatter-stl/libstdcpp/string/TestDataFormatterStdString.py", line 67, in test_with_run_command
"s summary wrong")
AssertionError: 'L"hello world! מזל טוב!\\0!\\0!!!!\\0\\0A\\0\\U0000fffd\\U0000fffd\\U0000fffd\\ [truncated]... != 'L"hello world! מזל טוב!"'
Diff is 2156 characters long. Set self.maxDiff to None to see it. : s summary wrong
Summary:
Printing a summary for an empty NSPathStore2 string currently prints random bytes behind the empty string pointer from memory (rdar://55575888).
It seems the reason for this is that the SourceSize parameter in the `ReadStringAndDumpToStreamOptions` - which is supposed to contain the string
length - actually uses the length 0 as a magic value for saying "read as much as possible from the buffer" which is clearly wrong for empty strings.
This patch adds another flag that indicates if we have know the string length or not and makes this behaviour dependent on that (which seemingly
was the original purpose of this magic value).
Reviewers: aprantl, JDevlieghere, shafik
Reviewed By: aprantl
Subscribers: christof, abidh, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D68010
Jorge Gorbe Moya