This patch extracts the logic to create a static variable member decl
into a helper. We will use this in an upcoming patch which will need to
call exactly the same logic from a separate part of the DWARF parser.
Changed the recently added `FindConstantOnVariableDefinition` to
not rely on MemberAttributes being non-const.
Original commit message:
"""
This patch removes the Objective-C accessibility workaround added in
5a477cfd90
(rdar://8492646). This allows us to make the local `MemberAttributes`
variable immutable, which is useful for some other work around this
function I was planning on doing.
We don't need the workaround anymore since compiler-support for giving
debuggers access to private ivars was done couple of years later in
d6cb4a858d
(rdar://10997647).
**Testing**
* Test-suite runs cleanly
"""
This patch removes the Objective-C accessibility workaround added in
5a477cfd90
(rdar://8492646). This allows us to make the local `MemberAttributes`
variable immutable, which is useful for some other work around this
function I was planning on doing.
We don't need the workaround anymore since compiler-support for giving
debuggers access to private ivars was done couple of years later in
d6cb4a858d
(rdar://10997647).
**Testing**
* Test-suite runs cleanly
This patch relands https://github.com/llvm/llvm-project/pull/71004 which
was reverted because the clang change it depends on was reverted.
In addition to the original patch, this PR includes a change to
`SymbolFileDWARF::ParseVariableDIE` to support CU-level variable
definitions that don't have locations, but represent a constant value.
Previously, when debug-maps were available, we would assume that a
variable with "static lifetime" (which in this case means "has a linkage
name") has a valid address, which isn't the case for non-locationed
constants. We could omit this additional change if we stopped attaching
linkage names to global non-locationed constants.
Original commit message:
"""
https://github.com/llvm/llvm-project/pull/71780 proposes moving the
`DW_AT_const_value` on inline static members from the declaration DIE to
the definition DIE. This patch makes sure the LLDB's expression
evaluator can continue to support static initialisers even if the
declaration doesn't have a `DW_AT_const_value` anymore.
Previously the expression evaluator would find the constant for a
VarDecl from its declaration `DW_TAG_member` DIE. In cases where the
initialiser was specified out-of-class, LLDB could find it during symbol
resolution.
However, neither of those will work for constants, since we don't have a
constant attribute on the declaration anymore and we don't have
constants in the symbol table.
"""
Depends on:
* https://github.com/llvm/llvm-project/pull/71780
lldb's AppleDWARFIndex is created with a few
`llvm::AppleAcceleratorTable` variables, but they only hold pointers to
the underlying data, which doesn't prevent the data owner (lldb's
DataBufferHeap) from being disposed.
Because of this, an asan build of lldb was showing an error in which a
jitted accelerator table was being fred before read, which made my lldb
fall in an infinite loop trying to parse corrupted accel table data.
This issue only happens when I'm using a jitted execution and not when
debugging a precompiled binary, probably because in the jit case the
underlying data has to necessarily be copied via gdb-remote instead of
mmaping a debug info file.
The correct fix seems to also store the underlying storage along with
the accelerator tables in AppleDWARFIndex.
Read the MD5 checksum from DWARF line tables and store it in the
corresponding support files.
This is a re-land after fixing an off-by-one error in LLDB's
ParseSupportFilesFromPrologue (fixed in #71984).
This fixes a subtle and previously harmless off-by-one bug in
ParseSupportFilesFromPrologue. The function accounts for the start index
being one-based for DWARF v4 and earlier and zero-based for DWARF v5 and
later. However, the same care wasn't taken for the end index.
This bug existed unnoticed because GetFileByIndex gracefully handles an
invalid index. However, the bug manifested itself after #71458, which
added a call to getFileNameEntry which requires the index to be valid.
No test as the bug cannot be observed without the changes from #71458.
Once that PR is merged, this will be covered by all the DWARF v5 tests.
This casued asserts:
llvm/lib/IR/Metadata.cpp:689:
void llvm::MDNode::resolve(): Assertion `isUniqued() && "Expected this to be uniqued"' failed.
See comments on the PR.
This also reverts the dependent follow-up commits, see below.
> When an LLDB user asks for the value of a static data member, LLDB
> starts by searching the Names accelerator table for the corresponding
> variable definition DIE. For static data members with out-of-class
> definitions that works fine, because those get represented as global
> variables with a location and making them eligible to be added to the
> Names table. However, in-class definitions won<E2><80><99>t get indexed because
> we usually don't emit global variables for them. So in DWARF we end
> up with a single `DW_TAG_member` that usually holds the constant
> initializer. But we don't get a corresponding CU-level
> `DW_TAG_variable` like we do for out-of-class definitions.
>
> To make it more convenient for debuggers to get to the value of
> inline static data members, this patch makes sure we emit definitions
> for static variables with constant initializers the same way we do
> for other static variables. This also aligns Clang closer to GCC,
> which produces CU-level definitions for inline statics and also
> emits these into `.debug_pubnames`.
>
> The implementation keeps track of newly created static data members.
> Then in `CGDebugInfo::finalize`, we emit a global `DW_TAG_variable`
> with a `DW_AT_const_value` for any of those declarations that didn't
> end up with a definition in the `DeclCache`.
>
> The newly emitted `DW_TAG_variable` will look as follows:
> ```
> 0x0000007b: DW_TAG_structure_type
> DW_AT_calling_convention (DW_CC_pass_by_value)
> DW_AT_name ("Foo")
> ...
>
> 0x0000008d: DW_TAG_member
> DW_AT_name ("i")
> DW_AT_type (0x00000062 "const int")
> DW_AT_external (true)
> DW_AT_declaration (true)
> DW_AT_const_value (4)
>
> Newly added
> vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
>
> 0x0000009a: DW_TAG_variable
> DW_AT_specification (0x0000008d "i")
> DW_AT_const_value (4)
> DW_AT_linkage_name ("_ZN2t2IiE1iIfEE")
> ```
>
> This patch also drops the `DW_AT_const_value` off of the declaration
> since we now always have it on the definition. This ensures that the
> `DWARFParallelLinker` can type-merge class with static members where
> we couldn't attach the constant on the declaration in some CUs.
This reverts commit 7c3707aea8.
This reverts commit cab0a19467.
This reverts commit 317481b3c8.
This reverts commit 15fc809404.
This reverts commit 470de2bbec.
https://github.com/llvm/llvm-project/pull/70639 proposes moving the
`DW_AT_const_value` on inline static members from the declaration DIE to
the definition DIE. This patch makes sure the LLDB's expression
evaluator can continue to support static initialisers even if the
declaration doesn't have a `DW_AT_const_value` anymore.
Previously the expression evaluator would find the constant for a
VarDecl from its declaration `DW_TAG_member` DIE. In cases where the
initialiser was specified out-of-class, LLDB could find it during symbol
resolution.
However, neither of those will work for constants, since we don't have a
constant attribute on the declaration anymore and we don't have
constants in the symbol table.
**Testing**
* If https://github.com/llvm/llvm-project/pull/70639 were to land
without this patch then most of the `TestConstStaticIntegralMember.py`
would start failing
This reverts commit ef3febadf6.
This caused an LLDB test failure on Linux for `lang/cpp/symbols/TestSymbols.test_dwo`:
```
make: Leaving directory '/home/worker/2.0.1/lldb-x86_64-debian/build/lldb-test-build.noindex/lang/cpp/symbols/TestSymbols.test_dwo'
runCmd: expression -- D::i
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0. HandleCommand(command = "expression -- D::i")
1. <user expression 0>:1:4: current parser token 'i'
2. <lldb wrapper prefix>:44:1: parsing function body '$__lldb_expr'
3. <lldb wrapper prefix>:44:1: in compound statement ('{}')
Stack dump without symbol names (ensure you have llvm-symbolizer in your PATH or set the environment var `LLVM_SYMBOLIZER_PATH` to point to it):
0 _lldb.cpython-39-x86_64-linux-gnu.so 0x00007fbcfcb08b87
1 _lldb.cpython-39-x86_64-linux-gnu.so 0x00007fbcfcb067ae
2 _lldb.cpython-39-x86_64-linux-gnu.so 0x00007fbcfcb0923f
3 libpthread.so.0 0x00007fbd07ab7140
```
And a failure in `TestCallStdStringFunction.py` on Linux aarch64:
```
--
Exit Code: -11
Command Output (stdout):
--
lldb version 18.0.0git (https://github.com/llvm/llvm-project.git revision ef3febadf6)
clang revision ef3febadf6
llvm revision ef3febadf6
--
Command Output (stderr):
--
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0. HandleCommand(command = "expression str")
1. <lldb wrapper prefix>:45:34: current parser token ';'
2. <lldb wrapper prefix>:44:1: parsing function body '$__lldb_expr'
3. <lldb wrapper prefix>:44:1: in compound statement ('{}')
#0 0x0000ffffb72a149c llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/lib/python3.8/site-packages/lldb/_[lldb.cpython-38-aarch64-linux-gnu.so](http://lldb.cpython-38-aarch64-linux-gnu.so/)+0x58c749c)
#1 0x0000ffffb729f458 llvm::sys::RunSignalHandlers() (/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/lib/python3.8/site-packages/lldb/_[lldb.cpython-38-aarch64-linux-gnu.so](http://lldb.cpython-38-aarch64-linux-gnu.so/)+0x58c5458)
#2 0x0000ffffb72a1bd0 SignalHandler(int) (/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/lib/python3.8/site-packages/lldb/_[lldb.cpython-38-aarch64-linux-gnu.so](http://lldb.cpython-38-aarch64-linux-gnu.so/)+0x58c7bd0)
#3 0x0000ffffbdd9e7dc (linux-vdso.so.1+0x7dc)
#4 0x0000ffffb71799d8 lldb_private::plugin::dwarf::SymbolFileDWARF::FindGlobalVariables(lldb_private::ConstString, lldb_private::CompilerDeclContext const&, unsigned int, lldb_private::VariableList&) (/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/lib/python3.8/site-packages/lldb/_[lldb.cpython-38-aarch64-linux-gnu.so](http://lldb.cpython-38-aarch64-linux-gnu.so/)+0x579f9d8)
#5 0x0000ffffb7197508 DWARFASTParserClang::FindConstantOnVariableDefinition(lldb_private::plugin::dwarf::DWARFDIE) (/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/lib/python3.8/site-packages/lldb/_[lldb.cpython-38-aarch64-linux-gnu.so](http://lldb.cpython-38-aarch64-linux-gnu.so/)+0x57bd508)
```
https://github.com/llvm/llvm-project/pull/70639 proposes moving the
`DW_AT_const_value` on inline static members from the declaration DIE to
the definition DIE. This patch makes sure the LLDB's expression
evaluator can continue to support static initialisers even if the
declaration doesn't have a `DW_AT_const_value` anymore.
Previously the expression evaluator would find the constant for a
VarDecl from its declaration `DW_TAG_member` DIE. In cases where the
initialiser was specified out-of-class, LLDB could find it during symbol
resolution.
However, neither of those will work for constants, since we don't have a
constant attribute on the declaration anymore and we don't have
constants in the symbol table.
**Testing**
* If https://github.com/llvm/llvm-project/pull/70639 were to land
without this patch then most of the `TestConstStaticIntegralMember.py`
would start failing
This completes the conversion of LocateSymbolFile into a SymbolLocator
plugin. The only remaining function is DownloadSymbolFileAsync which
doesn't really fit into the plugin model, and therefore moves into the
SymbolLocator class, while still relying on the plugins to do the
underlying work.
Often, we only care about the split-dwarf files that have failed to
load. This can be useful when diagnosing binaries with many separate
debug info files where only some have errors.
```
(lldb) help image dump separate-debug-info
List the separate debug info symbol files for one or more target modules.
Syntax: target modules dump separate-debug-info <cmd-options> [<filename> [<filename> [...]]]
Command Options Usage:
target modules dump separate-debug-info [-ej] [<filename> [<filename> [...]]]
-e ( --errors-only )
Filter to show only debug info files with errors.
-j ( --json )
Output the details in JSON format.
This command takes options and free-form arguments. If your arguments
resemble option specifiers (i.e., they start with a - or --), you must use
' -- ' between the end of the command options and the beginning of the
arguments.
'image' is an abbreviation for 'target modules'
```
I updated the following tests
```
# on Linux
bin/lldb-dotest -p TestDumpDwo
# on Mac
bin/lldb-dotest -p TestDumpOso
```
This change applies to both the table and JSON outputs.
---------
Co-authored-by: Tom Yang <toyang@fb.com>
During the recent refactoring (b120fe8d32) this enum was moved out of `RecordDecl`. During post-commit review it was found out that its association with `RecordDecl` should be expressed in the name.
This effectively moves a few functions from protected to public. In any
case, for the sake of having a cleaner SymbolFileDWARF API, it's better
if it's not a friend of a one of its consumers, DWARFASTParserClang.
Another effect of this change is that I can use SymbolFileDWARF for the
out-of-tree mojo dwarf parser, which relies on pretty much the same
functions that DWARFASTParserClang needs from SymbolFileDWARF.
While using dwarf5 `.debug_names` in internal large targets, we noticed
a performance issue (around 10 seconds delay) while `lldb-vscode` tries
to show `scopes` for a compile unit. Profiling shows the bottleneck is
inside `DebugNamesDWARFIndex::GetGlobalVariables` which linearly search
all index entries belongs to a compile unit.
This patch improves the performance by using the compile units list to
filter first before checking index entries. This significantly improves
the performance (drops from 10 seconds => under 1 second) in the split
dwarf situation because each compile unit has its own named index.
---------
Co-authored-by: jeffreytan81 <jeffreytan@fb.com>
When moving the GetTypeForDIE function from DWARFASTParserClang to
DWARFASTParser, I kept the signature as-is. To match the rest of the
function signatures in DWARFASTParser, remove the full name
(lldb_private::plugin::dwarf::DWARFDIE -> DWARFDIE) in the signature of
DWARFASTParser::GetTypeForDIE.
The "protected" was accidentally removed during refactoring of
SymbolFileDWARF. Reintroduce it and also make DWARFASTParser a friend
class since 040c4f4d98f3306e068521e3c218bdbc170f81f3 was merged and
won't build without it, as it dependeds on a method which was made
public by accident.
When the debug info refers to a dwo with relative `DW_AT_comp_dir` and
`DW_AT_dwo_name`, we only print the `DW_AT_comp_dir` in our error
message if we can't find it. This often isn't very helpful, especially
when the `DW_AT_comp_dir` is ".":
```
(lldb) fr v
error: unable to locate .dwo debug file "." for skeleton DIE 0x000000000000003c
```
I'm updating the error message to include both `DW_AT_comp_dir` (if it
exists) and `DW_AT_dwo_name` when the `DW_AT_dwo_name` is relative. The
behavior when `DW_AT_dwo_name` is absolute should be the same.
The method DWARFDebugInfoEntry::Extract needs to skip over all the data
in the debug_info / debug_types section for each DIE. It had the logic
to do so hardcoded inside a loop, when it already exists in a neatly
isolated function.
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.
**Background**
Prior to DWARFv4, there was no clear normative text on how to handle
static data members. Non-normative text suggested that compilers should
use `DW_AT_external` to mark static data members of structrues/unions.
Clang does this consistently. However, GCC doesn't, e.g., when the
structure/union is in an anonymous namespace (which is C++ standard
conformant). Additionally, GCC never emits `DW_AT_data_member_location`s
for union members (regardless of storage linkage and storage duration).
Since DWARFv5 (issue 161118.1), static data members get emitted as
`DW_TAG_variable`.
LLDB used to differentiate between static and non-static members by
checking the `DW_AT_external` flag and the absence of
`DW_AT_data_member_location`. With
[D18008](https://reviews.llvm.org/D18008) LLDB started to pretend that
union members always have a `0` `DW_AT_data_member_location` by default
(because GCC never emits these locations).
In [D124409](https://reviews.llvm.org/D124409) LLDB stopped checking the
`DW_AT_external` flag to account for the case where GCC doesn't emit the
flag for types in anonymous namespaces; instead we only check for
presence of `DW_AT_data_member_location`s.
The combination of these changes then meant that LLDB would never
correctly detect that a union has static data members.
**Solution**
Instead of unconditionally initializing the `member_byte_offset` to `0`
specifically for union members, this patch proposes to check for both
the absence of `DW_AT_data_member_location` and `DW_AT_declaration`,
which consistently gets emitted for static data members on GCC and
Clang.
We initialize the `member_byte_offset` to `0` anyway if we determine it
wasn't a static. So removing the special case for unions makes this code
simpler to reason about.
Long-term, we should just use DWARFv5's new representation for static
data members.
Fixes#68135
Currently this non-trivial calculation is repeated multiple times,
making it hard to reason about when the
`byte_offset`/`member_byte_offset` is being set or not.
This patch simply moves all those instances of the same calculation into
a helper function.
We return an optional to remain an NFC patch. Default initializing the
offset would make sense but requires further analysis and can be done in
a follow-up patch.
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
The LLVM implementation of DWARFDebugAbbrev does not have a way of
listing all the DW_FORM values that have been parsed but are unsupported
or otherwise unknown. AFAICT this functionality does not exist in LLVM
at all. Since my primary goal is to unify the implementations and not
judge the usefulness or completeness of this functionality, I decided to
move it out of LLDB's implementation of DWARFDebugAbbrev for the time
being.
I want to work towards unifying the implementations. It would be a lot
easier to do if LLDB's DWARFDebugAbbrev looked more similar to LLVM's
implementation, so this change moves in that direction.
This reverts commit dc3f758ddc.
Lit decided to show me the least interesting part of the
test output, but from what I gather on Mac OS the DWARF
stays in the object files (https://stackoverflow.com/a/12827463).
So either split DWARF options do nothing or they produce
files I don't know the name of that aren't .dwo, so I'm
skipping these tests on Darwin.
Fixes#28667
There's a bunch of ways to end up building split DWARF where the
DWO file is not next to the program file. On top of that you may
distribute the program in various ways, move files about, switch
machines, flatten the directories, etc.
This change adds a few more strategies to find DWO files:
* Appending the DW_AT_COMP_DIR and DWO name to all the debug
search paths.
* Appending the same to the binary's dir.
* Appending the DWO name (e.g. a/b/foo.dwo) to all the debug
search paths.
* Appending the DWO name to the binary's location.
* Appending the DWO filename (e.g. foo.dwo) to the debug
search paths.
* Appending the DWO filename to the binary's location.
They are applied in that order and some will be skipped
if the DW_AT_COMP_DIR is relative or absolute, same for
the DWO name (though that seems to always be relative).
This uses the setting target.debug-file-search-paths, which
is used for DWP files already.
The added tests likely do not cover every part of the
strategies listed, it's a best effort.
Reviewed By: clayborg
Differential Revision: https://reviews.llvm.org/D157609
ConstString can be implicitly converted into a llvm::StringRef. This is
very useful in many places, but it also hides places where we are
creating a ConstString only to use it as a StringRef for the entire
lifespan of the ConstString object.
I locally removed the implicit conversion and found some of the places we
were doing this.
Differential Revision: https://reviews.llvm.org/D159237
ConstStrings are super cheap to copy around. It is often more expensive
to pass a pointer and potentially dereference it than just to always copy it.
Differential Revision: https://reviews.llvm.org/D158043
