- if a synthetic child comes from the same hierarchy as its parent object, then it can't be cached by SharedPointer inside the synthetic provider, or it will cause a reference loop;
- but, if a synthetic child is made from whole cloth (e.g. from an expression, a memory region, ...), then it better be cached by SharedPointer, or it will be cleared out and cause an assert() to fail if used at a later point
For most cases of self-rooted synthetic children, we have a flag we set "IsSyntheticChildrenGenerated", but we were not using it to track caching. So, what ended up happening is each provider would set up its own cache, and if it got it wrong, a hard to diagnose crash would ensue
This patch fixes that by centralizing caching in ValueObjectSynthetic - if a provider returns a self-rooted child (as per the flag), then it gets cached centrally by the ValueObject itself
This cache is used only for lifetime management and not later retrieval of child values - a different cache handles that (because we might have a mix of self-rooted and properly nested child values for the same parent, we can't trivially use this lifetime cache for retrieval)
Fixes rdar://26480007
llvm-svn: 274683
However, they also contain fallback logic that - in cases where LLDB can't recognize the specific subclass - actually does run code in order to inspect those objects.
The argument for this logic was that these data types are critical enough that the risk of getting it wrong is outweighed by the advantage of always providing accurate child information.
Practical experience however shows that "po" - a code running data-inspection command - is quite frequently used, and not considered burdensome by users.
As such, this makes the code-running fallback in the data formatters a risk that carries very little actual reward. Also, unlike the time this code was originally written, we now have accurate class information for Objective-C, and thus we are less likely to improperly identify classes.
This commit removes support for the code-running fallback, and aligns the data formatters for NSArray, NSDictionary and NSSet to the general no-code-running behavior of other data formatters.
While it is possible for us to add support for some subclasses that are now no longer covered by static inspection alone, this is beyond the scope of this commit.
llvm-svn: 260664
Introduce the notion of Language-based formatter prefix/suffix
This is meant for languages that share certain data types but present them in syntatically different ways, such that LLDB can now have language-based awareness of which of the syntax variations it has to present to the user when formatting those values
This is goodness for new languages and interoperability, but is NFC for existing languages. As such, existing tests cover this
llvm-svn: 249587
Before we had:
ClangFunction
ClangUtilityFunction
ClangUserExpression
and code all over in lldb that explicitly made Clang-based expressions. This patch adds an Expression
base class, and three pure virtual implementations for the Expression kinds:
FunctionCaller
UtilityFunction
UserExpression
You can request one of these expression types from the Target using the Get<ExpressionType>ForLanguage.
The Target will then consult all the registered TypeSystem plugins, and if the type system that matches
the language can make an expression of that kind, it will do so and return it.
Because all of the real expression types need to communicate with their ExpressionParser in a uniform way,
I also added a ExpressionTypeSystemHelper class that expressions generically can vend, and a ClangExpressionHelper
that encapsulates the operations that the ClangExpressionParser needs to perform on the ClangExpression types.
Then each of the Clang* expression kinds constructs the appropriate helper to do what it needs.
The patch also fixes a wart in the UtilityFunction that to use it you had to create a parallel FunctionCaller
to actually call the function made by the UtilityFunction. Now the UtilityFunction can be asked to vend a
FunctionCaller that will run its function. This cleaned up a lot of boiler plate code using UtilityFunctions.
Note, in this patch all the expression types explicitly depend on the LLVM JIT and IR, and all the common
JIT running code is in the FunctionCaller etc base classes. At some point we could also abstract that dependency
but I don't see us adding another back end in the near term, so I'll leave that exercise till it is actually necessary.
llvm-svn: 247720
Enrico Granata