To make this work this patch extends LLDB to:
- Explicitly track the link_map address for each module. This is effectively the module handle, not sure why it wasn't already being stored off anywhere. As an extension later, it would be nice if someone were to add support for printing this as part of the modules list.
- Allow reading the per-thread data pointer via ptrace. I have added support for Linux here. I'll be happy to add support for FreeBSD once this is reviewed. OS X does not appear to have __thread variables, so maybe we don't need it there. Windows support should eventually be workable along the same lines.
- Make DWARF expressions track which module they originated from.
- Add support for the DW_OP_GNU_push_tls_address DWARF opcode, as generated by gcc and recent versions of clang. Earlier versions of clang (such as 3.2, which is default on Ubuntu right now) do not generate TLS debug info correctly so can not be supported here.
- Understand the format of the pthread DTV block. This is where it gets tricky. We have three basic options here:
1) Call "dlinfo" or "__tls_get_addr" on the inferior and ask it directly. However this won't work on core dumps, and generally speaking it's not a good idea for the debugger to call functions itself, as it has the potential to not work depending on the state of the target.
2) Use libthread_db. This is what GDB does. However this option requires having a version of libthread_db on the host cross-compiled for each potential target. This places a large burden on the user, and would make it very hard to cross-debug from Windows to Linux, for example. Trying to build a library intended exclusively for one OS on a different one is not pleasant. GDB sidesteps the problem and asks the user to figure it out.
3) Parse the DTV structure ourselves. On initial inspection this seems to be a bad option, as the DTV structure (the format used by the runtime to manage TLS data) is not in fact a kernel data structure, it is implemented entirely in useerland in libc. Therefore the layout of it's fields are version and OS dependent, and are not standardized.
However, it turns out not to be such a problem. All OSes use basically the same algorithm (a per-module lookup table) as detailed in Ulrich Drepper's TLS ELF ABI document, so we can easily write code to decode it ourselves. The only question therefore is the exact field layouts required. Happily, the implementors of libpthread expose the structure of the DTV via metadata exported as symbols from the .so itself, designed exactly for this kind of thing. So this patch simply reads that metadata in, and re-implements libthread_db's algorithm itself. We thereby get cross-platform TLS lookup without either requiring third-party libraries, while still being independent of the version of libpthread being used.
Test case included.
llvm-svn: 192922
1 - looking up the type basename in the type index
2 - iterate through all matches and look for decl contexts (namespace/class hierarchy) that match
The issue was the decl context matching wasn't watching for DW_TAG_class_type/DW_TAG_structure_type mismatches, and it wasn't also getting the name for DIE's that didn't have a DW_AT_name, but did have a DW_AT_specification that had a name.
llvm-svn: 186347
Major fixed to allow reading files that are over 4GB. The main problems were that the DataExtractor was using 32 bit offsets as a data cursor, and since we mmap all of our object files we could run into cases where if we had a very large core file that was over 4GB, we were running into the 4GB boundary.
So I defined a new "lldb::offset_t" which should be used for all file offsets.
After making this change, I enabled warnings for data loss and for enexpected implicit conversions temporarily and found a ton of things that I fixed.
Any functions that take an index internally, should use "size_t" for any indexes and also should return "size_t" for any sizes of collections.
llvm-svn: 173463
Fixed an issue that would happen when using debug map with DWARF in the .o files where we wouldn't ever track down the actual definition for a type when things were in namespaces. We now serialize the decl context information into an intermediate format which allows us to track down the correct definition for a type regardless of which DWARF symbol file it comes from. We do this by creating a "DWARFDeclContext" object that contains the DW_TAG + name for each item in a decl context which we can then use to veto potential accelerator table matches. For example, the accelerator tables store the basename of the type, so if you have "std::vector<int>", we would end up with an accelerator table entry for the type that contained "vector<int>", which we would then search for using a DWARFDeclContext object that contained:
[0] DW_TAG_class_type "vector<int>"
[1] DW_TAG_namespace "std"
This is currently used to track down forward declarations for things like "class a:🅱️:Foo;".
llvm-svn: 155488
a type when we have a forward declaration. We always have found a
type by basename, but now we also compare the decl context of the
die we are trying to complete with the matches we find from the accelerator
tables to ensure we get the right one.
llvm-svn: 149593
so that we don't have "fprintf (stderr, ...)" calls sprinkled everywhere.
Changed all needed locations over to using this.
For non-darwin, we log to stderr only. On darwin, we log to stderr _and_
to ASL (Apple System Log facility). This will allow GUI apps to have a place
for these error and warning messages to go, and also allows the command line
apps to log directly to the terminal.
llvm-svn: 147596
Be better at detecting when DWARF changes and handle this more
gracefully than asserting and exiting.
Also fixed up a bunch of system calls that weren't properly checking
for EINTR.
llvm-svn: 147559
to launch a process for debugging. Since this isn't supported on all platforms,
we need to do what we used to do if this isn't supported. I added:
bool
Platform::CanDebugProcess ();
This will get checked before trying to launch a process for debugging and then
fall back to launching the process through the current host debugger. This
should solve the issue for linux and keep the platform code clean.
Centralized logging code for logging errors, warnings and logs when reporting
things for modules or symbol files. Both lldb_private::Module and
lldb_private::SymbolFile now have the following member functions:
void
LogMessage (Log *log, const char *format, ...);
void
ReportWarning (const char *format, ...);
void
ReportError (const char *format, ...);
These will all output the module name and object (if any) such as:
"error: lldb.so ...."
"warning: my_archive.a(foo.o) ...."
This will keep the output consistent and stop a lot of logging calls from
having to try and output all of the information that uniquely identifies
a module or symbol file. Many places in the code were grabbing the path to the
object file manually and if the module represented a .o file in an archive, we
would see log messages like:
error: foo.a - some error happened
llvm-svn: 145219
to 30% of memory. The size doubling was killing us and we ended up with up to
just under 50% of empty capacity. Cleaning this up saves us a ton of memory.
llvm-svn: 145086
1 - the DIE collections no longer have the NULL tags which saves up to 25%
of the memory on typical C++ code
2 - faster parsing by not having to run the SetDIERelations() function anymore
it is done when parsing the DWARF very efficiently.
llvm-svn: 144983
we say that the vectors of DWARFDebugInfoEntry objects were the highest on the
the list.
With these changes we cut our memory usage by 40%!!! I did this by reducing
the size of the DWARFDebugInfoEntry from a previous:
uint32_t offset
uint32_t parent_idx
uint32_t sibling_idx
Abbrev * abbrev_ptr
which was 20 bytes, but rounded up to 24 bytes due to alignment. Now we have:
uint32_t offset
uint32_t parent_idx
uint32_t sibling_idx
uint32_t abbr_idx:15, // 32767 possible abbreviation codes
has_children:1, // 0 = no children, 1 = has children
tag:16; // DW_TAG_XXX value
This gets us down to 16 bytes per DIE. I tested some VERY large DWARF files
(900MB) and found there were only ~700 unique abbreviations, so 32767 should
be enough for any sane compiler. If it isn't there are built in assertions
that will fire off and tell us.
llvm-svn: 144975
stdarg formats to use __attribute__ format so the compiler can flag
incorrect uses. Fix all incorrect uses. Most of these are innocuous,
a few were resulting in crashes.
llvm-svn: 140185
Address ranges are now split up into two different tables:
- one in DWARFDebugInfo that is compile unit specific
- one in each DWARFCompileUnit that has exact function DIE offsets
This helps keep the size of the aranges down since the main table will get
uniqued and sorted and have consecutive ranges merged. We then only parse the
compile unit one on demand once we have determined that a compile unit contains
the address in question. We also now use the .debug_aranges section if there
is one instead of always indexing the DWARF manually.
NameToDIE now uses a UniqueCStringMap<dw_offset> map instead of a std::map.
std::map is very bulky as each node has 3 pointers and the key and value types.
This gets our NameToDIE entry down to 12 bytes each instead of 48 which saves
us a lot of memory when we have very large DWARF.
DWARFDebugAranges now has a smaller footprint for each range it contains to
save on memory.
llvm-svn: 139557
was failing if the DWARF was laid out in a certain way. The way
we detect C++ classes is now more robust so that a class method
can be defined outside of the class and refer to a definition inside
the class with a DW_AT_specification or DW_AT_abstract_origin attribute.
Fixed a case in Thread.cpp where we were looking up info in the frame
when we didn't need to. This was from some changes to support external
editors. Now the info is only looked up if needed.
llvm-svn: 137436
Fixed the DWARF plug-in such that when it gets all attributes for a DIE, that
it omits the DW_AT_sibling and DW_AT_declaration when getting attributes
from a DW_AT_abstract_origin or DW_AT_specification DIE.
llvm-svn: 118654
all of the calls inlined in the header file for better performance.
Fixed the summary for C string types (array of chars (with any combo if
modifiers), and pointers to chars) work in all cases.
Fixed an issue where a forward declaration to a clang type could cause itself
to resolve itself more than once if, during the resolving of the type itself
it caused something to try and resolve itself again. We now remove the clang
type from the forward declaration map in the DWARF parser when we start to
resolve it and avoid this additional call. This should stop any duplicate
members from appearing and throwing all the alignment of structs, unions and
classes.
llvm-svn: 117437
find the hotspots in our code when indexing the DWARF. A combination of
using SmallVector to avoid collection allocations, using fixed form
sizes when possible, and optimizing the hot loops contributed to the
speedup.
llvm-svn: 113961
debug map showed that the location lists in the .o files needed some
refactoring in order to work. The case that was failing was where a function
that was in the "__TEXT.__textcoal_nt" in the .o file, and in the
"__TEXT.__text" section in the main executable. This made symbol lookup fail
due to the way we were finding a real address in the debug map which was
by finding the section that the function was in in the .o file and trying to
find this in the main executable. Now the section list supports finding a
linked address in a section or any child sections. After fixing this, we ran
into issue that were due to DWARF and how it represents locations lists.
DWARF makes a list of address ranges and expressions that go along with those
address ranges. The location addresses are expressed in terms of a compile
unit address + offset. This works fine as long as nothing moves around. When
stuff moves around and offsets change between the remapped compile unit base
address and the new function address, then we can run into trouble. To deal
with this, we now store supply a location list slide amount to any location
list expressions that will allow us to make the location list addresses into
zero based offsets from the object that owns the location list (always a
function in our case).
With these fixes we can now re-link random address ranges inside the debugger
for use with our DWARF + debug map, incremental linking, and more.
Another issue that arose when doing the DWARF in the .o files was that GCC
4.2 emits a ".debug_aranges" that only mentions functions that are externally
visible. This makes .debug_aranges useless to us and we now generate a real
address range lookup table in the DWARF parser at the same time as we index
the name tables (that are needed because .debug_pubnames is just as useless).
llvm-gcc doesn't generate a .debug_aranges section, though this could be
fixed, we aren't going to rely upon it.
Renamed a bunch of "UINT_MAX" to "UINT32_MAX".
llvm-svn: 113829
Richard Mitton