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
an issue with the way the UnwindLLDB was handing out RegisterContexts: it
was making shared pointers to register contexts and then handing out just
the pointers (which would get put into shared pointers in the thread and
stack frame classes) and cause double free issues. MallocScribble helped to
find these issues after I did some other cleanup. To help avoid any
RegisterContext issue in the future, all code that deals with them now
returns shared pointers to the register contexts so we don't end up with
multiple deletions. Also now that the RegisterContext class doesn't require
a stack frame, we patched a memory leak where a StackFrame object was being
created and leaked.
Made the RegisterContext class not have a pointer to a StackFrame object as
one register context class can be used for N inlined stack frames so there is
not a 1 - 1 mapping. Updates the ExecutionContextScope part of the
RegisterContext class to never return a stack frame to indicate this when it
is asked to recreate the execution context. Now register contexts point to the
concrete frame using a concrete frame index. Concrete frames are all of the
frames that are actually formed on the stack of a thread. These concrete frames
can be turned into one or more user visible frames due to inlining. Each
inlined stack frame has the exact same register context (shared via shared
pointers) as any parent inlined stack frames all the way up to the concrete
frame itself.
So now the stack frames and the register contexts should behave much better.
llvm-svn: 122976
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
adding methods to C++ and objective C classes. In order to make methods, we
need the function prototype which means we need the arguments. Parsing these
could cause a circular reference that caused an assertion.
Added a new typedef for the clang opaque types which are just void pointers:
lldb::clang_type_t. This appears in lldb-types.h.
This was fixed by enabling struct, union, class, and enum types to only get
a forward declaration when we make the clang opaque qual type for these
types. When they need to actually be resolved, lldb_private::Type will call
a new function in the SymbolFile protocol to resolve a clang type when it is
not fully defined (clang::TagDecl::getDefinition() returns NULL). This allows
us to be a lot more lazy when parsing clang types and keeps down the amount
of data that gets parsed into the ASTContext for each module.
Getting the clang type from a "lldb_private::Type" object now takes a boolean
that indicates if a forward declaration is ok:
clang_type_t lldb_private::Type::GetClangType (bool forward_decl_is_ok);
So function prototypes that define parameters that are "const T&" can now just
parse the forward declaration for type 'T' and we avoid circular references in
the type system.
llvm-svn: 115012
defines that are in "llvm/Support/MachO.h". This should allow ObjectFileMachO
and ObjectContainerUniversalMachO to be able to be cross compiled in Linux.
Also did some cleanup on the ASTType by renaming it to ClangASTType and
renaming the header file. Moved a lot of "AST * + opaque clang type *"
functionality from lldb_private::Type over into ClangASTType.
llvm-svn: 109046
