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
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.
Parsing DWARF expressions currently does not support DW_OPs that are vendor
extensions. With this change expression parsing calls into SymbolFileDWARF for
unknown opcodes, which is the semantically "closest" plugin that we have right
now. Plugins can then extend SymbolFileDWARF to add support for vendor
extensions.
Reviewed By: labath
Differential Revision: https://reviews.llvm.org/D137247
When a process gets restarted TypeSystem objects associated with it
may get deleted, and any CompilerType objects holding on to a
reference to that type system are a use-after-free in waiting. Because
of the SBAPI, we don't have tight control over where CompilerTypes go
and when they are used. This is particularly a problem in the Swift
plugin, where the scratch TypeSystem can be restarted while the
process is still running. The Swift plugin has a lock to prevent
abuse, but where there's a lock there can be bugs.
This patch changes CompilerType to store a std::weak_ptr<TypeSystem>.
Most of the std::weak_ptr<TypeSystem>* uglyness is hidden by
introducing a wrapper class CompilerType::WrappedTypeSystem that has a
dyn_cast_or_null() method. The only sites that need to know about the
weak pointer implementation detail are the ones that deal with
creating TypeSystems.
rdar://101505232
Differential Revision: https://reviews.llvm.org/D136650
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
In split DWARF v5 files, the DWO id is no longer in the DW_AT_GNU_dwo_id
attribute. It's in the CU header instead. This change makes lldb look in
both places.
Differential Revision: https://reviews.llvm.org/D93444
Pavel Labath wrote in D73206:
The internal representation of DebugNames and Apple indexes is fixed by
the relevant (pseudo-)standards, so we can't really change it. The
question is how to efficiently (and cleanly) convert from the internal
representation to some common thing. The conversion from AppleIndex to
DIERef is trivial (which is not surprising as it was the first and the
overall design was optimized for that). With debug_names, the situation
gets more tricky. The internal representation of debug_names uses
CU-relative DIE offsets, but DIERef wants an absolute offset. That means
the index has to do more work to produce the common representation. And
it needs to do that for all results, even though a lot of the index
users are really interested only in a single entry. With the switch to
user_id_t, _all_ indexes would have to do some extra work to encode it,
only for their users to have to immediately decode it back. Having
a iterator/callback based api would allow us to minimize the impact of
that, as it would only need to happen for the entries that are really
used. And /I think/ we could make it interface returns DWARFDies
directly, and each index converts to that using the most direct approach
available.
Jan Kratochvil:
It also makes all the callers shorter as they no longer need to fetch
DWARFDIE from DIERef (and handling if not found by ReportInvalidDIERef)
but the callers are already served DWARFDIE which they need.
In some cases the DWARFDIE had to be fetched both by callee (DWARFIndex
implementation) and caller.
Differential Revision: https://reviews.llvm.org/D77970
The old name was a bit misleading because the functions actually return
contributions to the corresponding sections.
Differential revision: https://reviews.llvm.org/D77302
Change the return value of SymbolFileDWARF::DebugInfo from a pointer to
a reference, and remove all null checks.
Previously, we were not constructing the DebugInfo object when the
debug_info section was empty. Now we always construct the object but
it will return an empty list of dwarf units (a thing which it already
supported).
Summary:
This patch removes the bitrotted SymbolFileDWARF(Dwo)Dwp classes, and
replaces them with dwp support implemented directly inside
SymbolFileDWARFDwo, in a manner mirroring the implementation in llvm.
This patch does:
- add support for the .debug_cu_index section to our DWARFContext
- adds a llvm::DWARFUnitIndex argument to the DWARFUnit constructors.
This argument is used to look up the offsets of the debug_info and
debug_abbrev contributions in the sections of the dwp file.
- makes sure the creation of the DebugInfo object as well as the initial
discovery of DWARFUnits is thread-safe, as we can now call this
concurrently when doing parallel indexing.
This patch does not:
- use the DWARFUnitIndex to search for other kinds of contributions
(debug_loc, debug_ranges, etc.). This means that units which reference
these sections will not work correctly. These will be handled by
follow-up patches, but even the present level of support is sufficient
to enable basic functionality.
- Make the llvm::DWARFContext thread-safe. Right now, it just avoids this
problem by ensuring everything is initialized ahead of time. However,
this is something we will run into more often as we try to use more of
llvm, and so I plan to start looking into our options here.
Reviewers: JDevlieghere, aprantl, clayborg
Subscribers: mgorny, mgrang, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D73783
This is the second dwp preparatory patch. When a SymbolFileDWARFDwo will
hold more than one split unit, it will not be able to be uniquely owned
by a single DWARFUnit. I achieve this by changing the
unique_ptr<SymbolFileDWARFDwo> member of DWARFUnit to
shared_ptr<DWARFUnit>. The shared_ptr points to a DWARFUnit, but it is
in fact holding the entire SymbolFileDWARFDwo alive. This is the same
method used by llvm DWARFUnit (except that is uses the DWARFContext
class).
Differential Revision: https://reviews.llvm.org/D73782
Summary:
This is a preparatory patch to re-enable DWP support in lldb (we already
have code claiming to do that, but it has been completely broken for a
while now).
The idea of the new approach is to make the SymbolFileDWARFDwo class
handle both dwo and dwo files, similar to how llvm uses one DWARFContext
to handle the two.
The first step is to remove the assumption that a SymbolFileDWARFDwo
holds just a single compile unit, i.e. the GetBaseCompileUnit method.
This requires changing the way how we reach the skeleton compile unit
(and the lldb_private::CompileUnit) from a dwo unit, which was
previously done via GetSymbolFile()->GetBaseCompileUnit() (and some
virtual dispatch).
The new approach reuses the "user data" mechanism of DWARFUnits, which
was used to link dwarf units (both skeleton and split) to their
lldb_private counterparts. Now, this is done only for non-dwo units, and
instead of that, the dwo units holds a pointer to the relevant skeleton
unit.
Reviewers: JDevlieghere, aprantl, clayborg
Reviewed By: JDevlieghere, clayborg
Subscribers: arphaman, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D73781
Summary:
A *.cpp file header in LLDB (and in LLDB) should like this:
```
//===-- TestUtilities.cpp -------------------------------------------------===//
```
However in LLDB most of our source files have arbitrary changes to this format and
these changes are spreading through LLDB as folks usually just use the existing
source files as templates for their new files (most notably the unnecessary
editor language indicator `-*- C++ -*-` is spreading and in every review
someone is pointing out that this is wrong, resulting in people pointing out that this
is done in the same way in other files).
This patch removes most of these inconsistencies including the editor language indicators,
all the different missing/additional '-' characters, files that center the file name, missing
trailing `===//` (mostly caused by clang-format breaking the line).
Reviewers: aprantl, espindola, jfb, shafik, JDevlieghere
Reviewed By: JDevlieghere
Subscribers: dexonsmith, wuzish, emaste, sdardis, nemanjai, kbarton, MaskRay, atanasyan, arphaman, jfb, abidh, jsji, JDevlieghere, usaxena95, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D73258
Summary:
Our code was expecting that a single (symbol) file contains only one
kind of location lists. This is not correct (on non-apple platforms, at
least) as a file can compile units with different dwarf versions.
This patch moves the deteremination of location list flavour down to the
compile unit level, fixing this problem. I have also tried to rougly
align the code with the llvm DWARFUnit. Fully matching the API is not
possible because of how lldb's DWARFExpression lives separately from the
rest of the DWARF code, but this is at least a step in the right
direction.
Reviewers: JDevlieghere, aprantl, clayborg
Subscribers: dblaikie, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D71751
Summary:
The last responsibility of the SymbolVendor was to hold an owning
reference to the object file (in case symbols are being read from a
different file than the main module). As SymbolFile classes already hold
a non-owning reference to the object file, we can easily remove this
responsibility of the SymbolVendor by making the SymbolFile reference
owning.
Reviewers: JDevlieghere, clayborg, jingham
Subscribers: lldb-commits
Differential Revision: https://reviews.llvm.org/D65401
llvm-svn: 367392
Summary:
This commit achieves the following:
- Functions used to return a `TypeSystem *` return an
`llvm::Expected<TypeSystem *>` now. This means that the result of a call
is always checked, forcing clients to move more carefully.
- `TypeSystemMap::GetTypeSystemForLanguage` will either return an Error or a
non-null pointer to a TypeSystem.
Reviewers: JDevlieghere, davide, compnerd
Subscribers: jdoerfert, lldb-commits
Differential Revision: https://reviews.llvm.org/D65122
llvm-svn: 367360
Summary:
With the last round of refactors, supporting type units in dwo files
becomes almost trivial. This patch contains a couple of small fixes,
which taken as a whole make type units work in the split dwarf scenario
(both DWARF4 and DWARF5):
- DWARFContext: make sure we actually read the debug_types.dwo section
- DWARFUnit: set string offsets base on all units in the dwo file, not
just the main CU
- ManualDWARFIndex: index all units in the file
- SymbolFileDWARFDwo: Search for the single compile unit in the file, as
we can no longer assume it will be the first one
The last part makes it obvious that there is still some work to be done
here, namely that we do not support dwo files with multiple compile
units. That is something that should be easier after the DIERef
refactors, but it still requires more work.
Tests are added for the type units+split dwarf + dwarf4/5 scenarios, as
well as a test that checks we behave reasonably in the presence of dwo
files with multiple CUs.
Reviewers: clayborg, JDevlieghere, aprantl
Subscribers: arphaman, lldb-commits
Differential Revision: https://reviews.llvm.org/D63643
llvm-svn: 364274
Summary:
When dwo support was introduced, it used a trick where debug info
entries were referenced by the offset of the compile unit in the main
file, but the die offset was relative to the dwo file. Although there
was some elegance to it, this representation was starting to reach its
breaking point:
- the fact that the skeleton compile unit owned the DWO file meant that
it was impossible (or at least hard and unintuitive) to support DWO
files containing more than one compile unit. These kinds of files are
produced by LTO for example.
- it made it impossible to reference any DIEs in the skeleton compile
unit (although the skeleton units are generally empty, clang still
puts some info into them with -fsplit-dwarf-inlining).
- (current motivation) it made it very hard to support type units placed
in DWO files, as type units don't have any skeleton units which could
be referenced in the main file
This patch addresses this problem by introducing an new
"dwo_num" field to the DIERef class, whose purpose is to identify the
dwo file. It's kind of similar to the dwo_id field in DWARF5 unit
headers, but while this is a 64bit hash whose main purpose is to catch
file mismatches, this is just a smaller integer used to indentify a
loaded dwo file. Currently, this is based on the index of the skeleton
compile unit which owns the dwo file, but it is intended to be
eventually independent of that (to support the LTO use case).
Simultaneously the cu_offset is dropped to conserve space, as it is no
longer necessary. This means we can remove the "BaseObjectOffset" field
from the DWARFUnit class. It also means we can remove some of the
workarounds put in place to support the skeleton-unit+dwo-die combo.
More work is needed to remove all of them, which is out of scope of this
patch.
Reviewers: JDevlieghere, clayborg, aprantl
Subscribers: mehdi_amini, dexonsmith, arphaman, lldb-commits
Differential Revision: https://reviews.llvm.org/D63428
llvm-svn: 364009
Summary:
Instead of accessing the fields directly, use accessor functions to
provide access to the DIERef components. This allows us to decouple the
external interface, from the internal representation. The external
interface can use llvm::Optional and similar goodies, while the data can
still be stored internally in a more compact representation.
I also document the purpose of the existing DIERef fields.
The main motivation for this change is a need to introduce an additional
field to the DIERef class, but I believe the change has its own merit.
Reviewers: JDevlieghere, aprantl, clayborg
Subscribers: arphaman, lldb-commits
Differential Revision: https://reviews.llvm.org/D63400
llvm-svn: 363910
Previously it was storing a *pointer*, which left open the possibility
of this pointer being null. We never made use of that possibility (it
does not make sense), and most of the code was already assuming that.
However, there were a couple of null-checks scattered around the code.
This patch replaces the reference with a pointer, making the
non-null-ness explicit, and removes the remaining null-checks.
llvm-svn: 363381
Summary:
Type units don't represent actual compilations and a lot of the
operations that we do with lldb compile units (getting their line
tables, variables, etc.) don't make sense for them. There is also a lot
more of them (sometimes over 100x), so making them more lightweight pays
off.
The main change in this patch is that we stop creating lldb CompileUnits
for DWARF type units. The trickiest part here is that the SymbolFile
interface requires that we assign consecutive sequence IDs to the
compile units we create. As DWARF type and compile units can come in any
order (in v5), this means we can no longer use 1-1 mapping between DWARF
and lldb compile units. Instead I build a translation table between the
two indices. To avoid pessimizing the case where there are no type
units, I build the translation table only in case we have at least one
type unit.
Additionaly, I also tried to strenghted type safete by replacing
DWARFUnit with DWARFCompileUnit where applicable. Though that was not
stricly necessary, I found it a good way to ensure that the
transformations I am doing here make sense. In the places where I was
changing the function signatures, and where it was obvious that the
objects being handled were not null, I also replaced pointers with
references.
There shouldn't be any major functional change with this patch. The only
change I observed is that now the types in the type units will not be
parsed when one calls Module::ParseAllDebugSymbols, unless they are
referenced from other compile units. This makes sense, given how
ParseAllDebugSymbols is implemented (it iterates over all compile
units), and it only matters for one hand-writted test where I did not
bother to reference the types from the compile units (which I now do).
Reviewers: clayborg, JDevlieghere, aprantl
Subscribers: jdoerfert, lldb-commits
Differential Revision: https://reviews.llvm.org/D63005
llvm-svn: 363250
These variables were useful when looking up the compile unit index
required a binary search. Now that we can look up a compile unit index
in constant time, they are no longer needed.
llvm-svn: 361754
This moves the sections from SymbolFileDWARF to DWARFContext, where it
was trivial to do so. A couple of sections are still left in
SymbolFileDWARF. These will be handled by separate patches.
llvm-svn: 361127
Summary:
The previous attempt and moving section handling over to DWARFContext
(D59611) failed because it did not take into account the dwo sections
correctly. All DWARFContexts (even those in SymbolFileDWARFDwo) used the
main module for loading the sections, but in the dwo scenario some
sections should come from the dwo file.
This patch fixes that by making the DWARFContext aware of whether it a
dwo context or a regular one. A dwo context gets two sections lists, and
it knows where to look for a particular type of a section. This isn't
fully consistent with how the llvm DWARFContext behaves, because that
one leaves it up to the user to know whether it should ask for a dwo
section or not. However, for the time being, it seems useful to have a
single entity which knows how to peice together the debug info in dwo
and non-dwo scenarios. The rough roadmap for the future is:
- port over the rest of the sections to DWARFContext
- find a way to get rid of SymbolFileDWARFDwo/Dwp/DwpDwo. This will
likely involve adding the ability for the DWARFContext to spawn
dwo sub-contexts, similarly to how it's done in llvm.
- get rid of the special handling of the "dwo" contexts by making
sure everything knows whether it should ask for the .dwo version of
the section or not (similarly to how llvm's DWARFUnits do that)
To demonstrate how the DWARFContext should behave in this new world, I
port the debug_info section (which is debug_info.dwo in the dwo file)
handling to DWARFContext. The rest of the sections will come in
subsequent patches.
Reviewers: aprantl, clayborg, JDevlieghere
Subscribers: zturner, lldb-commits
Differential Revision: https://reviews.llvm.org/D62012
llvm-svn: 361000
Summary:
This patch adds the ability to precisely address debug info in
situations when a single file can have more than one debug-info-bearing
sections (as is the case with type units in DWARF v4).
The changes here can be classified into roughly three categories:
- the code which addresses a debug info by offset gets an additional
argument, which specifies the section one should look into.
- the DIERef class also gets an additional member variable specifying
the section. This way, code dealing with DIERefs can know which
section is the object referring to.
- the user_id_t encoding steals one bit from the dwarf_id field to store
the section. This means the total number of separate object files
(apple .o, or normal .dwo) is limited to 2 billion, but that is fine
as it's not possible to hit that number without switching to DWARF64
anyway.
This patch is functionally equivalent to (and inspired by) the two
patches (D61503 and D61504) by Jan Kratochvil, but there are differences
in the implementation:
- it uses an enum instead of a bool flag to differentiate the sections
- it increases the size of DIERef struct instead of reducing the amount
of addressable debug info
- it sets up DWARFDebugInfo to store the units in a single vector
instead of two. This sets us up for the future in which type units can
also live in the debug_info section, and I believe it's cleaner
because there's no need for unit index remapping
There are no tests with this patch as this is essentially NFC until
we start parsing type units from the debug_types section.
Reviewers: JDevlieghere, clayborg, aprantl
Subscribers: arphaman, jankratochvil, lldb-commits
Differential Revision: https://reviews.llvm.org/D61908
llvm-svn: 360872
Summary:
Instead of using the offset of the contained compile unit, we use it's
ID. The goal of this change is two-fold:
- free up space in the user_id_t representation to enable storing the
debug-info-carrying section (debug_types/debug_info) without
decreasing the amount of debug info we can address (as would be the
case with D61503).
- be a step towards supporting DWO files containing more than one unit
(important for debug_types+dwo, but can also happen with regular
dwo+lto). For this part to fully work we'd still need to add a way to
lookup the SymbolFileDWO without going through GetCompileUnitAtIndex,
but making sure things don't accidentally work because the SymbolFile
ID is the same as compile unit offset is a step towards that.
Reviewers: JDevlieghere, clayborg, aprantl
Subscribers: mehdi_amini, dexonsmith, tberghammer, jankratochvil, lldb-commits
Differential Revision: https://reviews.llvm.org/D61783
llvm-svn: 360565
D42892 changed a lot of code to use superclass DWARFUnit instead of its
subclass DWARFCompileUnit.
Finish this change more thoroughly for any *CompileUnit* -> *Unit* names.
Later patch will introduce DWARFTypeUnit which needs to be sometimes different
from DWARFCompileUnit and it would be confusing without this renaming.
Differential Revision: https://reviews.llvm.org/D61501
llvm-svn: 360443
This reverts commit r356682 because it breaks the DWO flavours of some
tests:
lldb-Suite :: lang/c/const_variables/TestConstVariables.py
lldb-Suite :: lang/c/local_variables/TestLocalVariables.py
lldb-Suite :: lang/c/vla/TestVLA.py
llvm-svn: 356773
This is mostly mechanical, and just moves the remaining non-DWO
related sections over to DWARFContext.
Differential Revision: https://reviews.llvm.org/D59611
llvm-svn: 356682
LLVM's DWARF parsing library has a class called DWARFContext which holds
all of the various DWARF data sections and lots of other information.
LLDB's on the other hand stores all of this directly in SymbolFileDWARF
/ SymbolFileDWARFDwo and passes this interface around through the
parsing library. Obviously this is incompatible with a world where the
low level interface does not depend on the high level interface, so we
need to move towards a model similar to LLVM's - i.e. all of the context
needed for low level parsing should be in a single class, and that class
gets passed around.
This patch is a small incremental step towards achieving this. The
interface and internals deviate from LLVM's for technical reasons, but
the high level idea is the same. The goal is, eventually, to remove all
occurrences of SymbolFileDWARF from the low level parsing code.
For now I've chosen a very simple section - the .debug_aranges section
to move into DWARFContext while leaving everything else unchanged. In
the short term this is a bit confusing because now the information you
need might come from either of 2 different locations. But it's a huge
refactor to do this all at once and runs a much higher risk of breaking
things. So I think it would be wise to do this in very small pieces.
TL;DR - No functional change
Differential Revision: https://reviews.llvm.org/D59562
llvm-svn: 356612
