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
Profiles show that `SymbolFileDWARF::FindFunctions` is both high firing (many thousands of calls) and fast running (35 µs mean).
Timers like this are noise and load for profiling systems, and can be removed.
rdar://100326595
Differential Revision: https://reviews.llvm.org/D134922
Now that we display an error when users try to get variables, but something in the debug info is preventing variables from showing up, track this with a new bool in each module's statistic information named "debugInfoHadVariableErrors".
This patch modifies the code to track when we have variable errors in a module and adds accessors to get/set this value. This value is used in the module statistics and we added a test to verify this value gets set correctly.
Differential Revision: https://reviews.llvm.org/D134508
Currently funciton lookup in the expression evaluator
fails to disambiguate member functions the are overloaded
on lvalue/rvalue reference-qualifiers. This happens because
we unconditionally set a `FunctionPrototype`s
`ExtProtoInfo::RefQualifier` to `RQ_None`. We lose
the ref-qualifiers in the synthesized AST and `clang::Sema`
fails to pick a correct overload candidate.
DWARF emits information about a function's ref-qualifiers
in the form of a boolean `DW_AT_rvalue_reference` (for rvalues)
and `DW_AT_reference` (for lvalues).
This patch sets the `FunctionPrototype::ExtProtoInfo::RefQualifier`
based on the DWARF attributes above.
**Testing**
* Added API test
llvm/llvm-project issue #57866
Differential Revision: https://reviews.llvm.org/D134661
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
This check was put in place to prevent static functions
from translation units outside the one that the current
expression is evaluated from taking precedence over functions
in the global namespace. However, this is really a different
bug. LLDB lumps functions from all CUs into a single AST and
ends up picking the file-static even when C++ context rules
wouldn't allow that to happen.
This patch removes the check so we apply the AsmLabel to all
FunctionDecls we create from DWARF if we have a linkage name
available. This makes the code-path easier to reason about and
allows calling static functions in contexts where we previously
would've chosen the wrong function.
We also flip the XFAILs in the API test to reflect what effect
this change has.
**Testing**
* Fixed API tests and added XFAIL
Differential Revision: https://reviews.llvm.org/D132231
When resolving symbols during IR execution, lldb makes a last effort attempt
to resolve external symbols from object files by approximate name matching.
It currently uses `CPlusPlusNameParser` to parse the demangled function name
and arguments for the unresolved symbol and its candidates. However, this
hand-rolled C++ parser doesn’t support ABI tags which, depending on the demangler,
get demangled into `[abi:tag]`. This lack of parsing support causes lldb to never
consider a candidate mangled function name that has ABI tags.
The issue reproduces by calling an ABI-tagged template function from the
expression evaluator. This is particularly problematic with the recent
addition of ABI tags to numerous libcxx APIs.
The issue stems from the fact that `clang::CodeGen` emits function
function calls using the mangled name inferred from the `FunctionDecl`
LLDB constructs from DWARF. Debug info often lacks information for
us to construct a perfect FunctionDecl resulting in subtle mangled
name inaccuracies.
This patch side-steps the problem of inaccurate `FunctionDecl`s by
attaching an `asm()` label to each `FunctionDecl` LLDB creates from DWARF.
`clang::CodeGen` consults this label to get the mangled name as one of
the first courses of action when emitting a function call.
LLDB already does this for C++ member functions as of
[675767a591](https://reviews.llvm.org/D40283)
**Testing**
* Added API tests
Differential Revision: https://reviews.llvm.org/D131974
This reverts commit 967df65a36.
This fixes test/Shell/SymbolFile/NativePDB/find-functions.cpp. When
looking up functions with the PDB plugins, if we are looking for a
full function name, we should use `GetName` to populate the `name`
field instead of `GetLookupName` since `GetName` has the more
complete information.
Context:
When setting a breakpoint by name, we invoke Module::FindFunctions to
find the function(s) in question. However, we use a Module::LookupInfo
to first process the user-provided name and figure out exactly what
we're looking for. When we actually perform the function lookup, we
search for the basename. After performing the search, we then filter out
the results using Module::LookupInfo::Prune. For example, given
a:🅱️:foo we would first search for all instances of foo and then filter
out the results to just names that have a:🅱️:foo in them. As one can
imagine, this involves a lot of debug info processing that we do not
necessarily need to be doing. Instead of doing one large post-processing
step after finding each instance of `foo`, we can filter them as we go
to save time.
Some numbers:
Debugging LLDB and placing a breakpoint on
llvm::itanium_demangle::StringView::begin without this change takes
approximately 70 seconds and resolves 31,920 DIEs. With this change,
placing the breakpoint takes around 30 seconds and resolves 8 DIEs.
Differential Revision: https://reviews.llvm.org/D129682
Fixing potential int overflow and uninitialized variables.
These were found by Coverity static code inspection.
Differential Revision: https://reviews.llvm.org/D130795
Resubmission of https://reviews.llvm.org/D130309 with the 2 patches that fixed the linux buildbot, and new windows fixes.
The FileSpec APIs allow users to modify instance variables directly by getting a non const reference to the directory and filename instance variables. This makes it impossible to control all of the times the FileSpec object is modified so we can clear cached member variables like m_resolved and with an upcoming patch caching if the file is relative or absolute. This patch modifies the APIs of FileSpec so no one can modify the directory or filename instance variables directly by adding set accessors and by removing the get accessors that are non const.
Many clients were using FileSpec::GetCString(...) which returned a unique C string from a ConstString'ified version of the result of GetPath() which returned a std::string. This caused many locations to use this convenient function incorrectly and could cause many strings to be added to the constant string pool that didn't need to. Most clients were converted to using FileSpec::GetPath().c_str() when possible. Other clients were modified to use the newly renamed version of this function which returns an actualy ConstString:
ConstString FileSpec::GetPathAsConstString(bool denormalize = true) const;
This avoids the issue where people were getting an already uniqued "const char *" that came from a ConstString only to put the "const char *" back into a "ConstString" object. By returning the ConstString instead of a "const char *" clients can be more efficient with the result.
The patch:
- Removes the non const GetDirectory() and GetFilename() get accessors
- Adds set accessors to replace the above functions: SetDirectory() and SetFilename().
- Adds ClearDirectory() and ClearFilename() to replace usage of the FileSpec::GetDirectory().Clear()/FileSpec::GetFilename().Clear() call sites
- Fixed all incorrect usage of FileSpec::GetCString() to use FileSpec::GetPath().c_str() where appropriate, and updated other call sites that wanted a ConstString to use the newly returned ConstString appropriately and efficiently.
Differential Revision: https://reviews.llvm.org/D130549
Teach libDebugInfo (llvm-dwarfdump) and lldb about DWARF tags and
attributes for pointer authentication. These values have been emitted by
Apple clang for several releases. Although upstream LLVM doesn't emit
these values yet, we hope to upstream that part sometime soon.
Differential revision: https://reviews.llvm.org/D130215
The FileSpect APIs allow users to modify instance variables directly by getting a non const reference to the directory and filename instance variables. This makes it impossibly to control all of the times the FileSpec object is modified so we can clear the cache. This patch modifies the APIs of FileSpec so no one can modify the directory or filename directly by adding set accessors and by removing the get accessors that are non const.
Many clients were using FileSpec::GetCString(...) which returned a unique C string from a ConstString'ified version of the result of GetPath() which returned a std::string. This caused many locations to use this convenient function incorrectly and could cause many strings to be added to the constant string pool that didn't need to. Most clients were converted to using FileSpec::GetPath().c_str() when possible. Other clients were modified to use the newly renamed version of this function which returns an actualy ConstString:
ConstString FileSpec::GetPathAsConstString(bool denormalize = true) const;
This avoids the issue where people were getting an already uniqued "const char *" that came from a ConstString only to put the "const char *" back into a "ConstString" object. By returning the ConstString instead of a "const char *" clients can be more efficient with the result.
The patch:
- Removes the non const GetDirectory() and GetFilename() get accessors
- Adds set accessors to replace the above functions: SetDirectory() and SetFilename().
- Adds ClearDirectory() and ClearFilename() to replace usage of the FileSpec::GetDirectory().Clear()/FileSpec::GetFilename().Clear() call sites
- Fixed all incorrect usage of FileSpec::GetCString() to use FileSpec::GetPath().c_str() where appropriate, and updated other call sites that wanted a ConstString to use the newly returned ConstString appropriately and efficiently.
Differential Revision: https://reviews.llvm.org/D130309
Reland 486787210d which broke tests on Arm and Windows.
* Windows -- on Windows const static data members with no out-of-class
definition do have valid addresses, in constract to other platforms
(Linux, macos) where they don't. Adjusted the test to expect success
on Windows and failure on other platforms.
* Arm -- `int128` is not available on 32-bit ARM, so disable the test
for this architecture.
This adds support for using const static integral data members as described by C++11 [class.static.data]p3
to LLDB's expression evaluator.
So far LLDB treated these data members are normal static variables. They already work as intended when they are declared in the class definition and then defined in a namespace scope. However, if they are declared and initialised in the class definition but never defined in a namespace scope, all LLDB expressions that use them will fail to link when LLDB can't find the respective symbol for the variable.
The reason for this is that the data members which are only declared in the class are not emitted into any object file so LLDB can never resolve them. Expressions that use these variables are expected to directly use their constant value if possible. Clang can do this for us during codegen, but it requires that we add the constant value to the VarDecl we generate for these data members.
This patch implements this by:
* parsing the constant values from the debug info and adding it to variable declarations we encounter.
* ensuring that LLDB doesn't implicitly try to take the address of expressions that might be an lvalue that points to such a special data member.
The second change is caused by LLDB's way of storing lvalues in the expression parser. When LLDB parses an expression, it tries to keep the result around via two mechanisms:
1. For lvalues, LLDB generates a static pointer variable and stores the address of the last expression in it: `T *$__lldb_expr_result_ptr = &LastExpression`
2. For everything else, LLDB generates a static variable of the same type as the last expression and then direct initialises that variable: `T $__lldb_expr_result(LastExpression)`
If we try to print a special const static data member via something like `expr Class::Member`, then LLDB will try to take the address of this expression as it's an lvalue. This means LLDB will try to take the address of the variable which causes that Clang can't replace the use with the constant value. There isn't any good way to detect this case (as there a lot of different expressions that could yield an lvalue that points to such a data member), so this patch also changes that we only use the first way of capturing the result if the last expression does not have a type that could potentially indicate it's coming from such a special data member.
This change shouldn't break most workflows for users. The only observable side effect I could find is that the implicit persistent result variables for const int's now have their own memory address:
Before this change:
```
(lldb) p i
(const int) $0 = 123
(lldb) p &$0
(const int *) $1 = 0x00007ffeefbff8e8
(lldb) p &i
(const int *) $2 = 0x00007ffeefbff8e8
```
After this change we capture `i` by value so it has its own value.
```
(lldb) p i
(const int) $0 = 123
(lldb) p &$0
(const int *) $1 = 0x0000000100155320
(lldb) p &i
(const int *) $2 = 0x00007ffeefbff8e8
```
Reviewed By: Michael137
Differential Revision: https://reviews.llvm.org/D81471
The case comes out of how BOLT handles transformation of
DW_AT_low_pc/DW_AT_high_pc into DW_AT_low_pc/DW_AT_high_pc
with latter being 0.
Reviewed By: clayborg
Differential Revision: https://reviews.llvm.org/D127889
This patch renames DW_ACCESS_to_AccessType function and move it to the abstract
DWARFASTParser, since there is no clang-specific code there. This is useful for
plugins other than Clang.
Reviewed By: shafik, bulbazord
Differential Revision: https://reviews.llvm.org/D114719
This patch moves ParseChildArrayInfo out of DWARFASTParserClang in order
to decouple Clang-specific logic from DWARFASTParser.
Reviewed By: clayborg
Differential Revision: https://reviews.llvm.org/D114668
Signed-off-by: Luís Ferreira <contact@lsferreira.net>
See [[ https://github.com/llvm/llvm-project/issues/55040 | issue 55040 ]] where static members of classes declared in the anonymous namespace are incorrectly returned as member fields from lldb::SBType::GetFieldAtIndex(). It appears that attrs.member_byte_offset contains a sentinel value for members that don't have a DW_AT_data_member_location.
Reviewed By: labath
Differential Revision: https://reviews.llvm.org/D124409
IIUC, the purpose of CopyUniqueClassMethodTypes is to link together
class definitions in two compile units so that we only have a single
definition of a class. It does this by adding entries to the die_to_type
and die_to_decl_ctx maps.
However, the direction of the linking seems to be reversed. It is taking
entries from the class that has not yet been parsed, and copying them to
the class which has been parsed already -- i.e., it is a very
complicated no-op.
Changing the linking order allows us to revert the changes in D13224
(while keeping the associated test case passing), and is sufficient to
fix PR54761, which was caused by an undesired interaction with that
patch.
Differential Revision: https://reviews.llvm.org/D124370
As a preparation for parallelizing loading of symbols (D122975),
it is necessary to use just one thread pool to avoid using
a thread pool from inside a task of another thread pool.
Differential Revision: https://reviews.llvm.org/D123226
UniqueCStringMap<T> objects are a std::vector<UniqueCStringMap::Entry> objects where the Entry object contains a ConstString + T. The values in the vector are sorted first by ConstString and then by the T value. ConstString objects are simply uniqued "const char *" values and when we compare we use the actual string pointer as the value we sort by. This caused a problem when we saved the symbol table name indexes and debug info indexes to disk in one process when they were sorted, and then loaded them into another process when decoding them from the cache files. Why? Because the order in which the ConstString objects were created are now completely different and the string pointers will no longer be sorted in the new process the cache was loaded into.
The unit tests created for the initial patch didn't catch the encoding and decoding issues of UniqueCStringMap<T> because they were happening in the same process and encoding and decoding would end up createing sorted UniqueCStringMap<T> objects due to the constant string pool being exactly the same.
This patch does the sort and also reserves the right amount of entries in the UniqueCStringMap::m_map prior to adding them all to avoid doing multiple allocations.
Added a unit test that loads an object file from yaml, and then I created a cache file for the original file and removed the cache file's signature mod time check since we will generate an object file from the YAML, and use that as the object file for the Symtab object. Then we load the cache data from the array of symtab cache bytes so that the ConstString "const char *" values will not match the current process, and verify we can lookup the 4 names from the object file in the symbol table.
Differential Revision: https://reviews.llvm.org/D124572
Rather than looking up by offset - actually use the hash table to
perform faster lookup where possible. (for DWARFv4 DWP compilation units
the hash isn't in the header - it's in the root DIE, but to parse the
DIE you need the abbrev section and to get the abbrev section you need
the index - so in that case lookup by offset is required)
This diff introduces a new symbol on-demand which skips
loading a module's debug info unless explicitly asked on
demand. This provides significant performance improvement
for application with dynamic linking mode which has large
number of modules.
The feature can be turned on with:
"settings set symbols.load-on-demand true"
The feature works by creating a new SymbolFileOnDemand class for
each module which wraps the actual SymbolFIle subclass as member
variable. By default, most virtual methods on SymbolFileOnDemand are
skipped so that it looks like there is no debug info for that module.
But once the module's debug info is explicitly requested to
be enabled (in the conditions mentioned below) SymbolFileOnDemand
will allow all methods to pass through and forward to the actual SymbolFile
which would hydrate module's debug info on-demand.
In an internal benchmark, we are seeing more than 95% improvement
for a 3000 modules application.
Currently we are providing several ways to on demand hydrate
a module's debug info:
* Source line breakpoint: matching in supported files
* Stack trace: resolving symbol context for an address
* Symbolic breakpoint: symbol table match guided promotion
* Global variable: symbol table match guided promotion
In all above situations the module's debug info will be on-demand
parsed and indexed.
Some follow-ups for this feature:
* Add a command that allows users to load debug info explicitly while using a
new or existing command when this feature is enabled
* Add settings for "never load any of these executables in Symbols On Demand"
that takes a list of globs
* Add settings for "always load the the debug info for executables in Symbols
On Demand" that takes a list of globs
* Add a new column in "image list" that shows up by default when Symbols On
Demand is enable to show the status for each shlib like "not enabled for
this", "debug info off" and "debug info on" (with a single character to
short string, not the ones I just typed)
Differential Revision: https://reviews.llvm.org/D121631
Dave Lee