The class is only used from one place, which is trivial to implement
using the llvm class.
The main difference is that in the new implementation, the ranges are
parsed each time anew (instead of being parsed at startup and cached). I
believe this is fine because:
- this is already how things work with DWARF v5 debug_rnglists
- parsing debug_ranges is fairly fast (definitely faster than rnglists)
- generally, this result will be cached at a higher level anyway.
Browsing the code I did find one instance where that is not the case --
SymbolFileDWARF::ResolveFunctionAndBlock -- which is called each time we
resolve an address (to the block level). However, this function is
already pretty suboptimal: it first traverses the DIE tree (which
involves parsing all the DIE attributes) to find the correct block, then
it parses them again to construct the `lldb_private::Block`
representation, and *then* it uses the ID of the block DIE it found in
the first step to look up the `Block` object. If this turns out to be a
bottleneck, I think there are better ways to optimize it than caching
the debug_ranges parse.
The motiviation for this is that DWARFDebugRanges sorts the block
ranges, even though the order of the ranges is load-bearing (in the
absence of DW_AT_low_pc, the "base address" of a scope is determined by
the first range entry). Delaying the parsing (and sorting) step makes it
easier to access the first entry.
This patch removes all of the Set.* methods from Status.
This cleanup is part of a series of patches that make it harder use the
anti-pattern of keeping a long-lives Status object around and updating
it while dropping any errors it contains on the floor.
This patch is largely NFC, the more interesting next steps this enables
is to:
1. remove Status.Clear()
2. assert that Status::operator=() never overwrites an error
3. remove Status::operator=()
Note that step (2) will bring 90% of the benefits for users, and step
(3) will dramatically clean up the error handling code in various
places. In the end my goal is to convert all APIs that are of the form
` ResultTy DoFoo(Status& error)
`
to
` llvm::Expected<ResultTy> DoFoo()
`
How to read this patch?
The interesting changes are in Status.h and Status.cpp, all other
changes are mostly
` perl -pi -e 's/\.SetErrorString/ = Status::FromErrorString/g' $(git
grep -l SetErrorString lldb/source)
`
plus the occasional manual cleanup.
This PR is in reference to porting LLDB on AIX.
Link to discussions on llvm discourse and github:
1. https://discourse.llvm.org/t/port-lldb-to-ibm-aix/80640
2. #101657
The complete changes for porting are present in this draft PR:
https://github.com/llvm/llvm-project/pull/102601
The changes on this PR are intended to avoid namespace collision for
certain typedefs between lldb and other platforms:
1. tid_t --> lldb::tid_t
2. offset_t --> lldb::offset_t
The only change vs. the first version of the patch is that I've made
DWARFUnit linking thread-safe/unit. This was necessary because, during
the
indexing step, two skeleton units could attempt to associate themselves
with the split unit.
The original commit message was:
I ran into this when LTO completely emptied two compile units, so they
ended up with the same hash (see #100375). Although, ideally, the
compiler would try to ensure we don't end up with a hash collision even
in this case, guaranteeing their absence is practically impossible. This
patch ensures this situation does not bring down lldb.
I ran into this when LTO completely emptied two compile units, so they
ended up with the same hash (see #100375). Although, ideally, the
compiler would try to ensure we don't end up with a hash collision even
in this case, guaranteeing their absence is practically impossible. This
patch ensures this situation does not bring down lldb.
We currently cannot represent abbreviation codes with more than 16 bits,
and we were lldb-asserting if we ever ran into one. While I haven't seen
any real DWARF with these kinds of abbreviations, it is possible to hit
this with handcrafted evil dwarf, due some sort of corruptions, or just
bugs (the addition of PeekDIEName makes these bugs more likely, as the
function blindly dereferences offsets within the debug info section) .
Missing abbreviations were already reporting an error. This patch turns
sure that large abbreviations into an error as well, and adds a test for
both cases.
Dwarf 5 says "There is no requirement that the entries be ordered in any
particular way" in 2.17.3 Non-Contiguous Address Ranges for rnglist.
Some places assume the ranges are already sorted but it's not.
For example, when [parsing function
info](bc8a427620/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp (L922-L927)),
it validates low and hi address of the function: GetMinRangeBase returns
the first range entry base and GetMaxRangeEnd returns the last range
end. If low >= hi, it stops parsing this function. This causes missing
inline stack frames for those functions.
This change fixes it and updates the test
`lldb/test/Shell/SymbolFile/DWARF/x86/debug_rnglists.s` so that two
ranges in `.debug_rnglists` are out of order and `image lookup -v -s
lookup_rnglists` is still able to produce sorted ranges for the inner
block.
Updates:
- The previous patch changed the default behavior to not load dwos in
`DWARFUnit`
~~`SymbolFileDWARFDwo *GetDwoSymbolFile(bool load_all_debug_info =
false);`~~
`SymbolFileDWARFDwo *GetDwoSymbolFile(bool load_all_debug_info = true);`
- This broke some lldb-shell tests (see
https://green.lab.llvm.org/green/view/LLDB/job/as-lldb-cmake/16273/)
- TestDebugInfoSize.py
- with symbol on-demand, by default statistics dump only reports
skeleton debug info size
- `statistics dump -f` will load all dwos. debug info = skeleton debug
info + all dwo debug info
Currently running `statistics dump` will trigger lldb to load debug info
that's not yet loaded (eg. dwo files). Resulted in a delay in the
command return, which, can be interrupting.
This patch also added a new option `--load-all-debug-info` asking
statistics to dump all possible debug info, which will force loading all
debug info available if not yet loaded.
Currently running `statistics dump` will trigger lldb to load debug info
that's not yet loaded (eg. dwo files). Resulted in a delay in the
command return, which, can be interrupting.
This patch also added a new option `--load-all-debug-info` asking
statistics to dump all possible debug info, which will force loading all
debug info available if not yet loaded.
When using split DWARF with .dwp files we had an issue where sometimes
the DWO file within the .dwp file would be parsed _before_ the skeleton
compile unit. The DWO file expects to be able to always be able to get a
link back to the skeleton compile unit. Prior to this fix, the only time
the skeleton compile unit backlink would get set, was if the unit
headers for the main executable have been parsed _and_ if the unit DIE
was parsed in that DWARFUnit. This patch ensures that we can always get
the skeleton compile unit for a DWO file by adding a function:
```
DWARFCompileUnit *DWARFUnit::GetSkeletonUnit();
```
Prior to this fix DWARFUnit had some unsafe accessors that were used to
store two different things:
```
void *DWARFUnit::GetUserData() const;
void DWARFUnit::SetUserData(void *d);
```
This was used by SymbolFileDWARF to cache the `lldb_private::CompileUnit
*` for a SymbolFileDWARF and was also used to store the `DWARFUnit *`
for SymbolFileDWARFDwo. This patch clears up this unsafe usage by adding
two separate accessors and ivars for this:
```
lldb_private::CompileUnit *DWARFUnit::GetLLDBCompUnit() const { return m_lldb_cu; }
void DWARFUnit::SetLLDBCompUnit(lldb_private::CompileUnit *cu) { m_lldb_cu = cu; }
DWARFCompileUnit *DWARFUnit::GetSkeletonUnit();
void DWARFUnit::SetSkeletonUnit(DWARFUnit *skeleton_unit);
```
This will stop anyone from calling `void *DWARFUnit::GetUserData()
const;` and casting the value to an incorrect value.
A crash could occur in `SymbolFileDWARF::GetCompUnitForDWARFCompUnit()`
when the `non_dwo_cu`, which is a backlink to the skeleton compile unit,
was not set and was NULL. There is an assert() in the code, and then the
code just will kill the program if the assert isn't enabled because the
code looked like:
```
if (dwarf_cu.IsDWOUnit()) {
DWARFCompileUnit *non_dwo_cu =
static_cast<DWARFCompileUnit *>(dwarf_cu.GetUserData());
assert(non_dwo_cu);
return non_dwo_cu->GetSymbolFileDWARF().GetCompUnitForDWARFCompUnit(
*non_dwo_cu);
}
```
This is now fixed by calling the `DWARFUnit::GetSkeletonUnit()` which
will correctly always get the skeleton compile uint for a DWO file
regardless of if the skeleton unit headers have been parse or if the
skeleton unit DIE wasn't parsed yet.
To implement the ability to get the skeleton compile units, I added code
the DWARFDebugInfo.cpp/.h that make a map of DWO ID -> skeleton
DWARFUnit * that gets filled in for DWARF5 when the unit headers are
parsed. The `DWARFUnit::GetSkeletonUnit()` will end up parsing the unit
headers of the main executable to fill in this map if it already hasn't
been done. For DWARF4 and earlier we maintain a separate map that gets
filled in only for any DWARF4 compile units that have a DW_AT_dwo_id or
DW_AT_gnu_dwo_id attributes. This is more expensive, so this is done
lazily and in a thread safe manor. This allows us to be as efficient as
possible when using DWARF5 and also be backward compatible with DWARF4 +
split DWARF.
There was also an issue that stopped type lookups from succeeding in
`DWARFDIE SymbolFileDWARF::GetDIE(const DIERef &die_ref)` where it
directly was accessing the `m_dwp_symfile` ivar without calling the
accessor function that could end up needing to locate and load the .dwp
file. This was fixed by calling the
`SymbolFileDWARF::GetDwpSymbolFile()` accessor to ensure we always get a
valid value back if we can find the .dwp file. Prior to this fix it was
down which APIs were called and if any APIs were called that loaded the
.dwp file, it worked fine, but it might not if no APIs were called that
did cause it to get loaded.
When we have valid debug info indexes and when the lldb index cache was
enabled, this would cause this issue to show up more often.
I modified an existing test case to test that all of this works
correctly and doesn't crash.
This patch replaces uses of StringRef::{starts,ends}with with
StringRef::{starts,ends}_with for consistency with
std::{string,string_view}::{starts,ends}_with in C++20.
I'm planning to deprecate and eventually remove
StringRef::{starts,ends}with.
As a followup of https://github.com/llvm/llvm-project/pull/67851, I'm
defining a new namespace `lldb_plugin::dwarf` for the classes in this
Plugins/SymbolFile/DWARF folder. This change is very NFC and helped me
with exporting the necessary symbols for my out-of-tree language plugin.
The only class that I didn't change is ClangDWARFASTParser, because that
shouldn't be in the same namespace as the generic language-agnostic
dwarf parser.
It would be a good idea if other plugins follow the same namespace
scheme.
I plan on replacing LLDB's DWARFUnitHeader implementation with LLVM's.
LLVM's DWARFUnitHeader::extract applies the DWARFUnitIndex::Entry to a
given DWARFUnitHeader outside of the extraction because the index entry
is only relevant to one place where we may parse DWARFUnitHeaders
(specifically when we're creating a DWARFUnit in a DWO context). To ease
the transition, I've reshaped LLDB's implementation to look closer to
LLVM's.
Reviewed By: aprantl, fdeazeve
Differential Revision: https://reviews.llvm.org/D151919
LLDB's implementation of DWARFDataExtractor has a method that returns a
llvm::DWARFDataExtractor. In some cases, like DebugNamesDWARFIndex::Create, we
were passing an LLVM::DWARFDataExtractor to a function that expects a
LLVM:DataExtractor by value. This is causing slicing of the derived class.
While slicing is not inherently bad, it can be dangerous if the constructor of
the derived class mutates the base class in a way that leaves it in an invalid
state after slicing.
Differential Revision: https://reviews.llvm.org/D153913
lldb's and llvm's implementations of DWARFAbbreviationDeclarationSet are
now close enough (almost the same, actually) to replace lldb's with
llvm's wholesale. llvm's is also tested against the same kinds of
scenarios that lldb's is tested against so we can remove lldb's tests
here. (see: llvm/unittests/DebugInfo/DWARF/DWARFDebugAbbrevTest.cpp).
Differential Revision: https://reviews.llvm.org/D152476
The purpose of this method is to get the list of attributes of a
DebugInfoEntry. Prior to this change we were passing in a mutable
reference to a DWARFAttributes object and having the method fill it in
for us while returning the size of the filled out list. But
instead of doing that, we can just return a `DWARFAttributes` object
ourselves since every caller creates a new list before calling
GetAttributes.
Differential Revision: https://reviews.llvm.org/D150402
Similar to dw_form_t, dw_attr_t is typedef'd to be a uint16_t. LLVM
defines their type `llvm::dwarf::Attribute` as an enum backed by a
uint16_t. Switching to the LLVM type buys us type checking and the
requirement of explicit casts.
Differential Revision: https://reviews.llvm.org/D150299
Most of the code changed here dates back to 2010, when LLDB was first
introduced upstream, as such it benefits from a slight cleanup.
The method "dump" is not used anywhere nor is it tested, so this commit removes
it.
The "findRanges" method returns a boolean which is never checked and indicates
whether the method found anything/assigned a range map to the out parameter.
This commit folds the out parameter into the return type of the method.
A handful of typedefs were also never used and therefore removed.
Differential Revision: https://reviews.llvm.org/D150363
Add MSP430 to the list of available targets, implement MSP430 ABI, add support for debugging targets with 16-bit address size.
The update is intended for use with MSPDebug, a GDB server implementation for MSP430.
Reviewed By: bulbazord, DavidSpickett
Differential Revision: https://reviews.llvm.org/D146965
Add MSP430 to the list of available targets, implement MSP430 ABI, add support for debugging targets with 16-bit address size.
The update is intended for use with MSPDebug, a GDB server implementation for MSP430.
Reviewed By: bulbazord, DavidSpickett
Differential Revision: https://reviews.llvm.org/D146965
This came out of from https://discourse.llvm.org/t/dwarf-dwp-4gb-limit/63902
With big binaries we can have .dwp files where .debug_info.dwo section can grow
beyond 4GB. We would like to support this in LLVM and in LLDB.
The plan is to enable manual parsing of cu/tu index in DWARF library
(https://reviews.llvm.org/D137882), and then
switch internal index data structure to 64 bit.
For the second part is to enable 64bit offset support in LLDB with
this patch.
Reviewed By: labath
Differential Revision: https://reviews.llvm.org/D138618
This came out of from https://discourse.llvm.org/t/dwarf-dwp-4gb-limit/63902
With big binaries we can have .dwp files where .debug_info.dwo section can grow
beyond 4GB. We would like to support this in LLVM and in LLDB.
The plan is to enable manual parsing of cu/tu index in DWARF library
(https://reviews.llvm.org/D137882), and then
switch internal index data structure to 64 bit.
For the second part is to enable 64bit offset support in LLDB with
this patch.
Depends on D139955
Reviewed By: labath
Differential Revision: https://reviews.llvm.org/D138618
This came out of from https://discourse.llvm.org/t/dwarf-dwp-4gb-limit/63902
With big binaries we can have .dwp files where .debug_info.dwo section can grow
beyond 4GB. We would like to support this in LLVM and in LLDB.
The plan is to enable manual parsing of cu/tu index in DWARF library
(https://reviews.llvm.org/D137882), and then
switch internal index data structure to 64 bit.
For the second part is to enable 64bit offset support in LLDB with
this patch.
Depends on D139955
Reviewed By: labath
Differential Revision: https://reviews.llvm.org/D138618
Changed contribution data structure to 64 bit. I added the 32bit and 64bit
accessors to make it explicit where we use 32bit and where we use 64bit. Also to
make sure sure we catch all the cases where this data structure is used.
Reviewed By: dblaikie
Differential Revision: https://reviews.llvm.org/D139379
Changed contribution data structure to 64 bit. I added the 32bit and 64bit
accessors to make it explicit where we use 32bit and where we use 64bit. Also to
make sure sure we catch all the cases where this data structure is used.
Reviewed By: dblaikie
Differential Revision: https://reviews.llvm.org/D139379
In preparation for eanbling 64bit support in LLDB switching to use llvm::formatv
instead of format MACROs.
Reviewed By: labath, JDevlieghere
Differential Revision: https://reviews.llvm.org/D139955
Summary:
Changed contribution data structure to 64 bit. I added the 32bit and 64bit
accessors to make it explicit where we use 32bit and where we use 64bit. Also to
make sure sure we catch all the cases where this data structure is used.
Profiles show that `DWARFUnit::ExtractUnitDIENoDwoIfNeeded` is both high firing (tens of thousands of calls) and fast running (15 µs mean).
Timers like this are noise and load for profiling systems, and can be removed.
rdar://100326595
Differential Revision: https://reviews.llvm.org/D134920
When debugging using Fission (-gsplit-dwarf), we can sometimes have issues loading .dwo files if they are missing or if the path was relative and we were unable to locate the file. We can also skip loading due to DWO ID mismatch or if a .dwp file doesn't contain a matching .dwo file. Also .dwo files could be updated due to a recompile and if the user debugs an executable that was linked against the old .dwo file, it could fail to load the information.
This patch adds a m_dwo_error to DWARFUnit that can be get/set and will cause "frame variable" to show errors when there are .dwo/.dwp issues informing the user about the error.
Differential Revision: https://reviews.llvm.org/D134252
D131437 caused heap-use-after-free failures when testing TestCreateAfterAttach.py in asan mode, and "regular" crashes outside of asan.
This appears to be due to a mismatch in a couple places where we choose to clear the DIEs. When we clear the DIE of a skeleton unit, we unconditionally clear the DIE of the DWO unit if it exists. However, `~ScopedExtractDIEs()` only looks at the skeleton unit when deciding to clear. If we decide to clear the skeleton unit because it is now unused, we end up clearing the DWO unit that _is_ used. This change adds a guard by checking `m_cancel_scopes` to prevent clearing the DWO unit.
This is 100% reproducible by running TestCreateAfterAttach.py in asan mode, although it only seems to reproduce in our internal build, so no test case is added here. If someone has suggestions on how to write one, I can add it.
Reviewed By: labath
Differential Revision: https://reviews.llvm.org/D133790
Summary:
Many times when debugging variables might not be available even though a user can successfully set breakpoints and stops somewhere. Letting the user know will help users fix these kinds of issues and have a better debugging experience.
Examples of this include:
- enabling -gline-tables-only and being able to set file and line breakpoints and yet see no variables
- unable to open object file for DWARF in .o file debugging for darwin targets due to modification time mismatch or not being able to locate the N_OSO file.
This patch adds an new API to SBValueList:
lldb::SBError lldb::SBValueList::GetError();
object so that if you request a stack frame's variables using SBValueList SBFrame::GetVariables(...), you can get an error the describes why the variables were not available.
This patch adds the ability to get an error back when requesting variables from a lldb_private::StackFrame when calling GetVariableList.
It also now shows an error in response to "frame variable" if we have debug info and are unable to get varialbes due to an error as mentioned above:
(lldb) frame variable
error: "a.o" object from the "/tmp/libfoo.a" archive: either the .o file doesn't exist in the archive or the modification time (0x63111541) of the .o file doesn't match
Reviewers: labath JDevlieghere aadsm yinghuitan jdoerfert sscalpone
Subscribers:
Differential Revision: https://reviews.llvm.org/D133164
Many times when debugging variables might not be available even though a user can successfully set breakpoints and stops somewhere. Letting the user know will help users fix these kinds of issues and have a better debugging experience.
Examples of this include:
- enabling -gline-tables-only and being able to set file and line breakpoints and yet see no variables
- unable to open object file for DWARF in .o file debugging for darwin targets due to modification time mismatch or not being able to locate the N_OSO file.
This patch adds an new API to SBValueList:
lldb::SBError lldb::SBValueList::GetError();
object so that if you request a stack frame's variables using SBValueList SBFrame::GetVariables(...), you can get an error the describes why the variables were not available.
This patch adds the ability to get an error back when requesting variables from a lldb_private::StackFrame when calling GetVariableList.
It also now shows an error in response to "frame variable" if we have debug info and are unable to get varialbes due to an error as mentioned above:
(lldb) frame variable
error: "a.o" object from the "/tmp/libfoo.a" archive: either the .o file doesn't exist in the archive or the modification time (0x63111541) of the .o file doesn't match
Differential Revision: https://reviews.llvm.org/D133164
When fission is enabled, we were indexing the skeleton CU _and_ the .dwo CU. Issues arise when users enable compiler options that add extra data to the skeleton CU (like -fsplit-dwarf-inlining) and there can end up being types in the skeleton CU due to template parameters. We never want to index this information since the .dwo file has the real definition, and we really don't want function prototypes from this info since all parameters are removed. The index doesn't work correctly if it does index the skeleton CU as the DIE offset will assume it is from the .dwo file, so even if we do index the skeleton CU, the index entries will try and grab information from the .dwo file using the wrong DIE offset which can cause errors to be displayed or even worse, if the DIE offsets is valid in the .dwo CU, the wrong DIE will be used.
We also fix DWO ID detection to use llvm::Optional<uint64_t> to make sure we can load a .dwo file with a DWO ID of zero.
Differential Revision: https://reviews.llvm.org/D131437
Fixing potential int overflow and uninitialized variables.
These were found by Coverity static code inspection.
Differential Revision: https://reviews.llvm.org/D130795
