The way this code was updated in
dd95877958 meant that if the first module
did not have the symbol, the iteration stopped as returning true means
stop. So only if every module had the symbol would we find it, in the
last module.
Invert the condition to break when we find the first instance, which is
what the previous code did.
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.
This patch fixes the SymbolFilePDBTests::TestMaxMatches(...) by making
it test what it was testing before, see comments in the test case for
details.
It also disables TestUniqueTypes4.py for now until we can debug or fix
why it isn't working.
This patch revives the effort to get this Phabricator patch into
upstream:
https://reviews.llvm.org/D137900
This patch was accepted before in Phabricator but I found some
-gsimple-template-names issues that are fixed in this patch.
A fixed up version of the description from the original patch starts
now.
This patch started off trying to fix Module::FindFirstType() as it
sometimes didn't work. The issue was the SymbolFile plug-ins didn't do
any filtering of the matching types they produced, and they only looked
up types using the type basename. This means if you have two types with
the same basename, your type lookup can fail when only looking up a
single type. We would ask the Module::FindFirstType to lookup "Foo::Bar"
and it would ask the symbol file to find only 1 type matching the
basename "Bar", and then we would filter out any matches that didn't
match "Foo::Bar". So if the SymbolFile found "Foo::Bar" first, then it
would work, but if it found "Baz::Bar" first, it would return only that
type and it would be filtered out.
Discovering this issue lead me to think of the patch Alex Langford did a
few months ago that was done for finding functions, where he allowed
SymbolFile objects to make sure something fully matched before parsing
the debug information into an AST type and other LLDB types. So this
patch aimed to allow type lookups to also be much more efficient.
As LLDB has been developed over the years, we added more ways to to type
lookups. These functions have lots of arguments. This patch aims to make
one API that needs to be implemented that serves all previous lookups:
- Find a single type
- Find all types
- Find types in a namespace
This patch introduces a `TypeQuery` class that contains all of the state
needed to perform the lookup which is powerful enough to perform all of
the type searches that used to be in our API. It contain a vector of
CompilerContext objects that can fully or partially specify the lookup
that needs to take place.
If you just want to lookup all types with a matching basename,
regardless of the containing context, you can specify just a single
CompilerContext entry that has a name and a CompilerContextKind mask of
CompilerContextKind::AnyType.
Or you can fully specify the exact context to use when doing lookups
like: CompilerContextKind::Namespace "std"
CompilerContextKind::Class "foo"
CompilerContextKind::Typedef "size_type"
This change expands on the clang modules code that already used a
vector<CompilerContext> items, but it modifies it to work with
expression type lookups which have contexts, or user lookups where users
query for types. The clang modules type lookup is still an option that
can be enabled on the `TypeQuery` objects.
This mirrors the most recent addition of type lookups that took a
vector<CompilerContext> that allowed lookups to happen for the
expression parser in certain places.
Prior to this we had the following APIs in Module:
```
void
Module::FindTypes(ConstString type_name, bool exact_match, size_t max_matches,
llvm::DenseSet<lldb_private::SymbolFile *> &searched_symbol_files,
TypeList &types);
void
Module::FindTypes(llvm::ArrayRef<CompilerContext> pattern, LanguageSet languages,
llvm::DenseSet<lldb_private::SymbolFile *> &searched_symbol_files,
TypeMap &types);
void Module::FindTypesInNamespace(ConstString type_name,
const CompilerDeclContext &parent_decl_ctx,
size_t max_matches, TypeList &type_list);
```
The new Module API is much simpler. It gets rid of all three above
functions and replaces them with:
```
void FindTypes(const TypeQuery &query, TypeResults &results);
```
The `TypeQuery` class contains all of the needed settings:
- The vector<CompilerContext> that allow efficient lookups in the symbol
file classes since they can look at basename matches only realize fully
matching types. Before this any basename that matched was fully realized
only to be removed later by code outside of the SymbolFile layer which
could cause many types to be realized when they didn't need to.
- If the lookup is exact or not. If not exact, then the compiler context
must match the bottom most items that match the compiler context,
otherwise it must match exactly
- If the compiler context match is for clang modules or not. Clang
modules matches include a Module compiler context kind that allows types
to be matched only from certain modules and these matches are not needed
when d oing user type lookups.
- An optional list of languages to use to limit the search to only
certain languages
The `TypeResults` object contains all state required to do the lookup
and store the results:
- The max number of matches
- The set of SymbolFile objects that have already been searched
- The matching type list for any matches that are found
The benefits of this approach are:
- Simpler API, and only one API to implement in SymbolFile classes
- Replaces the FindTypesInNamespace that used a CompilerDeclContext as a
way to limit the search, but this only worked if the TypeSystem matched
the current symbol file's type system, so you couldn't use it to lookup
a type in another module
- Fixes a serious bug in our FindFirstType functions where if we were
searching for "foo::bar", and we found a "baz::bar" first, the basename
would match and we would only fetch 1 type using the basename, only to
drop it from the matching list and returning no results
This commit factors out the logic building each component of a qualified
name into its own function so that it may be reused by a future commit,
while also simplifying the logic of assembling these pieces together by
using llvm::interleave.
There was duplicated (and complex) code querying whether tags were
type-like tags (i.e. class or struct); this has been factored out into a
helper function.
There was also a comment about not comparing identical DIEs without ever
performing that check; this comment has been removed. It was likely a
result of copy paste from another function in this same file which
actually does that check.
This commit reverts the changes in
https://github.com/llvm/llvm-project/pull/71780 and all of its follow-up
patches.
We got reports of the `.debug_names/.debug_gnu_pubnames/gdb_index/etc.`
sections growing by a non-trivial amount for some large projects. While
GCC emits definitions for static data member constants into the Names
index, they do so *only* for explicitly `constexpr` members. We were
indexing *all* constant-initialized const-static members, which is
likely where the significant size difference comes from. However, only
emitting explicitly `constexpr` variables into the index doesn't seem
like a good way forward, since from clang's perspective `const`-static
integrals are `constexpr` too, and that shouldn't be any different in
the debug-info component. Also, as new code moves to `constexpr` instead
of `const` static for constants, such solution would just delay the
growth of the Names index.
To prevent the size regression we revert to not emitting definitions for
static data-members that have no location.
To support access to such constants from LLDB we'll most likely have to
have to make LLDB find the constants by looking at the containing class
first.
The function FindDefinitionTypeForDWARFDeclContext loops over all DIEs
corresponding to types with a certain name and compares the context of
each found DIE with the context of a target DIE. However, the target DIE
never changes throughout this search, and yet we recompute its
DeclContext on every iteration of the search. This is wasteful because
the method is not exactly free (see
DWARFDebugInfoEntry::GetDWARFDeclContextStatic).
I've plumbed the LLVM DebugInfoD client into LLDB, and added automatic
downloading of DWP files to the SymbolFileDWARF.cpp plugin. If you have
DEBUGINFOD_URLS set to a space delimited set of web servers, LLDB will
try to use them as a last resort when searching for DWP files. If you do
*not* have that environment variable set, nothing should be changed.
There's also a setting, per @clayborg 's suggestion, that will override
the environment variable, or can be used instead of the environment
variable. The setting is why I also needed to add an API to the
llvm-debuginfod library
### Test Plan:
Suggestions are welcome here. I should probably have some positive and
negative tests, but I wanted to get the diff up for people who have a
clue what they're doing to rip it to pieces before spending too much
time validating the initial implementation.
---------
Co-authored-by: Kevin Frei <freik@meta.com>
Co-authored-by: Alex Langford <nirvashtzero@gmail.com>
A previous patch to llvm allowed the DWARFUnitIndex class to handle
.debug_info.dwo and .debug_types.dwo sections to go over 4GB by checking
for this case and fixing up the DWARFUnitIndex. LLDB's DWARF parser
tries to use the llvm's DWARF parser when it can, and LLDB's DWARF
parser uses the llvm::DWARFUnitIndex which should allow us to load large
.dwp files, but there were a few things missing on the LLDB front:
- support for parsing DWARFUnit objects when the offset exceeds 4GB due
to a 32 bit truncation issue
- not populating the required DWARF sections when we call
DWARFContext::GetAsLLVM() which didn't allow the fixups to happen as the
data was missing.
This patch fixes these issues and now allows LLDB to parse large .dwp
files without issues. The issue was discovered when running the "target
modules dump separate-debug-info" command on one of these binaries that
used a large .dwp file.
This is unfortunately hard to test without creating a huge .dwp file, so
there are currently no tests for this that I can think of adding that
wouldn't cause disk space constraints or making testing times longer by
producing a huge .dwp file.
This is a follow up patch after .debug_names can now emit local type
unit entries when we compile with type units + DWARF5 + .debug_names.
The pull request that added this functionality was:
https://github.com/llvm/llvm-project/pull/70515
This patch makes sure that the DebugNamesDWARFIndex in LLDB will not
manually need to parse type units if they have a valid index. It also
fixes the index to be able to correctly extract name entries that
reference type unit DIEs. Added a test to verify things work as
expected.
Part of fixes for #72913.
clang emits `DW_AT_alignment` attribute, however LLDB didn't respect it,
resulting in incorrect RecordDecls built by lldb.
This only fixes non-inheritance cases. The inheritance case will be
handled in a follow-up patch.
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.
