the way LLDB lazily gets complete definitions for types within the debug info.
When we run across a class/struct/union definition in the DWARF, we will only
parse the full definition if we need to. This works fine for top level types
that are assigned directly to variables and arguments, but when we have a
variable with a class, lets say "A" for this example, that has a member:
"B *m_b". Initially we don't need to hunt down a definition for this class
unless we are ever asked to do something with it ("expr m_b->getDecl()" for
example). With my previous approach to lazy type completion, we would be able
to take a "A *a" and get a complete type for it, but we wouldn't be able to
then do an "a->m_b->getDecl()" unless we always expanded all types within a
class prior to handing out the type. Expanding everything is very costly and
it would be great if there were a better way.
A few months ago I worked with the llvm/clang folks to have the
ExternalASTSource class be able to complete classes if there weren't completed
yet:
class ExternalASTSource {
....
virtual void
CompleteType (clang::TagDecl *Tag);
virtual void
CompleteType (clang::ObjCInterfaceDecl *Class);
};
This was great, because we can now have the class that is producing the AST
(SymbolFileDWARF and SymbolFileDWARFDebugMap) sign up as external AST sources
and the object that creates the forward declaration types can now also
complete them anywhere within the clang type system.
This patch makes a few major changes:
- lldb_private::Module classes now own the AST context. Previously the TypeList
objects did.
- The DWARF parsers now sign up as an external AST sources so they can complete
types.
- All of the pure clang type system wrapper code we have in LLDB (ClangASTContext,
ClangASTType, and more) can now be iterating through children of any type,
and if a class/union/struct type (clang::RecordType or ObjC interface)
is found that is incomplete, we can ask the AST to get the definition.
- The SymbolFileDWARFDebugMap class now will create and use a single AST that
all child SymbolFileDWARF classes will share (much like what happens when
we have a complete linked DWARF for an executable).
We will need to modify some of the ClangUserExpression code to take more
advantage of this completion ability in the near future. Meanwhile we should
be better off now that we can be accessing any children of variables through
pointers and always be able to resolve the clang type if needed.
llvm-svn: 123613
values or persistent expression variables. Now if an expression consists of
a value that is a child of a variable, or of a persistent variable only, we
will create a value object for it and make a ValueObjectConstResult from it to
freeze the value (for program variables only, not persistent variables) and
avoid running JITed code. For everything else we still parse up and JIT code
and run it in the inferior.
There was also a lot of clean up in the expression code. I made the
ClangExpressionVariables be stored in collections of shared pointers instead
of in collections of objects. This will help stop a lot of copy constructors on
these large objects and also cleans up the code considerably. The persistent
clang expression variables were moved over to the Target to ensure they persist
across process executions.
Added the ability for lldb_private::Target objects to evaluate expressions.
We want to evaluate expressions at the target level in case we aren't running
yet, or we have just completed running. We still want to be able to access the
persistent expression variables between runs, and also evaluate constant
expressions.
Added extra logging to the dynamic loader plug-in for MacOSX. ModuleList objects
can now dump their contents with the UUID, arch and full paths being logged with
appropriate prefix values.
Thread hardened the Communication class a bit by making the connection auto_ptr
member into a shared pointer member and then making a local copy of the shared
pointer in each method that uses it to make sure another thread can't nuke the
connection object while it is being used by another thread.
Added a new file to the lldb/test/load_unload test that causes the test a.out file
to link to the libd.dylib file all the time. This will allow us to test using
the DYLD_LIBRARY_PATH environment variable after moving libd.dylib somewhere else.
llvm-svn: 121745
cases when getting the clang type:
- need only a forward declaration
- need a clang type that can be used for layout (members and args/return types)
- need a full clang type
This allows us to partially parse the clang types and be as lazy as possible.
The first case is when we just need to declare a type and we will complete it
later. The forward declaration happens only for class/union/structs and enums.
The layout type allows us to resolve the full clang type _except_ if we have
any modifiers on a pointer or reference (both R and L value). In this case
when we are adding members or function args or return types, we only need to
know how the type will be laid out and we can defer completing the pointee
type until we later need it. The last type means we need a full definition for
the clang type.
Did some renaming of some enumerations to get rid of the old "DC" prefix (which
stands for DebugCore which is no longer around).
Modified the clang namespace support to be almost ready to be fed to the
expression parser. I made a new ClangNamespaceDecl class that can carry around
the AST and the namespace decl so we can copy it into the expression AST. I
modified the symbol vendor and symbol file plug-ins to use this new class.
llvm-svn: 118976
debug information and you evaluated an expression, a crash would occur as a
result of an unchecked pointer.
Added the ability to get the expression path for a ValueObject. For a rectangle
point child "x" the expression path would be something like: "rect.top_left.x".
This will allow GUI and command lines to get ahold of the expression path for
a value object without having to explicitly know about the hierarchy. This
means the ValueObject base class now has a "ValueObject *m_parent;" member.
All ValueObject subclasses now correctly track their lineage and are able
to provide value expression paths as well.
Added a new "--flat" option to the "frame variable" to allow for flat variable
output. An example of the current and new outputs:
(lldb) frame variable
argc = 1
argv = 0x00007fff5fbffe80
pt = {
x = 2
y = 3
}
rect = {
bottom_left = {
x = 1
y = 2
}
top_right = {
x = 3
y = 4
}
}
(lldb) frame variable --flat
argc = 1
argv = 0x00007fff5fbffe80
pt.x = 2
pt.y = 3
rect.bottom_left.x = 1
rect.bottom_left.y = 2
rect.top_right.x = 3
rect.top_right.y = 4
As you can see when there is a lot of hierarchy it can help flatten things out.
Also if you want to use a member in an expression, you can copy the text from
the "--flat" output and not have to piece it together manually. This can help
when you want to use parts of the STL in expressions:
(lldb) frame variable --flat
argc = 1
argv = 0x00007fff5fbffea8
hello_world._M_dataplus._M_p = 0x0000000000000000
(lldb) expr hello_world._M_dataplus._M_p[0] == '\0'
llvm-svn: 116532
bool ValueObject::GetIsConstant() const;
void ValueObject::SetIsConstant();
This will stop anything from being re-evaluated within the value object so
that constant result value objects can maintain their frozen values without
anything being updated or changed within the value object.
Made it so the ValueObjectConstResult can be constructed with an
lldb_private::Error object to allow for expression results to have errors.
Since ValueObject objects contain error objects, I changed the expression
evaluation in ClangUserExpression from
static Error
ClangUserExpression::Evaluate (ExecutionContext &exe_ctx,
const char *expr_cstr,
lldb::ValueObjectSP &result_valobj_sp);
to:
static lldb::ValueObjectSP
Evaluate (ExecutionContext &exe_ctx, const char *expr_cstr);
Even though expression parsing is borked right now (pending fixes coming from
Sean Callanan), I filled in the implementation for:
SBValue SBFrame::EvaluateExpression (const char *expr);
Modified all expression code to deal with the above changes.
llvm-svn: 115589
results. The clang opaque type for the expression result will be added to the
Target's ASTContext, and the bytes will be stored in a DataBuffer inside
the new object. The class is named: ValueObjectConstResult
Now after an expression is evaluated, we can get a ValueObjectSP back that
contains a ValueObjectConstResult object.
Relocated the value object dumping code into a static function within
the ValueObject class instead of being in the CommandObjectFrame.cpp file
which is what contained the code to dump variables ("frame variables").
llvm-svn: 115578
Greg Clayton