SB API clients can describe the failure message in a more natural
way for their UI, this doesn't add information for them.
Differential Revision: https://reviews.llvm.org/D74585
<rdar://problem/49953304>
This reimplements commit 6b2979c123 and updates
the tests to reflect the addition of the alternate symbol attribute.
Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
D73303 was failing on Fedora Linux and so it was disabled by Skip the
AssertFrameRecognizer test for Linux.
I find no easy way how to find out if it gets recognized as
`__assert_fail` or `__GI___assert_fail` as during `Process` ctor
libc.so.6 is not yet loaded by the debuggee.
DWARF symbol `__GI___assert_fail` overrides the ELF symbol `__assert_fail`.
While external debug info (=DWARF) gets disabled for testsuite (D55859)
that sure does not apply for real world usage.
Differential Revision: https://reviews.llvm.org/D74252
This reverts commit cf1046c716.
Reverted: https://reviews.llvm.org/D74252
It fixed testsuite but broke real world functionality where is not used:
settings set symbols.enable-external-lookup false
D73303 was failing on Fedora Linux and so it was disabled by Skip the
AssertFrameRecognizer test for Linux.
On Fedora 30 x86_64 I have:
$ readelf -Ws /lib64/libc.so.6 |grep '^Symbol\|.*assert_fail'
Symbol table '.dynsym' contains 2362 entries:
630: 0000000000030520 70 FUNC GLOBAL DEFAULT 14 __assert_fail@@GLIBC_2.2.5
Symbol table '.symtab' contains 22711 entries:
922: 000000000002275a 15 FUNC LOCAL DEFAULT 14 __assert_fail_base.cold
18044: 0000000000030520 70 FUNC LOCAL DEFAULT 14 __GI___assert_fail
20081: 00000000000303a0 370 FUNC LOCAL DEFAULT 14 __assert_fail_base
21766: 0000000000030520 70 FUNC GLOBAL DEFAULT 14 __assert_fail
The patch should never expect __GI___assert_fail:
.symtab can be present or not but that should not change that
__assert_fail always wins - it is always present from .dynsym and it can
never be overriden by __GI___assert_fail as __GI___assert_fail has only
local binding. Global binding is preferred since D63540.
External debug info symbols do not matter since D55859 (and DWARF should
never be embedded in system libc.so.6).
Differential Revision: https://reviews.llvm.org/D74252
This patch skips the AssertFrameRecognizer test for Linux since it appears to
fail on certain distributions (AFAIK Fedora & ArchLinux).
The failure happen because the thread don't set the current frame to
the most relevant one. So the stopped location doesn't match with what
the test is expecting.
The test will be enabled again after I'll be able to reproduce the failure
on one of those platform and fix the issue.
Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
EXCLUDE_FROM_ALL means something else for add_lit_testsuite as it does
for something like add_executable. Distinguish between the two by
renaming the variable and making it an argument to add_lit_testsuite.
Differential revision: https://reviews.llvm.org/D74168
When a thread stops, this checks depending on the platform if the top frame is
an abort stack frame. If so, it looks for an assert stack frame in the upper
frames and set it as the most relavant frame when found.
To do so, the StackFrameRecognizer class holds a "Most Relevant Frame" and a
"cooked" stop reason description. When the thread is about to stop, it checks
if the current frame is recognized, and if so, it fetches the recognized frame's
attributes and applies them.
rdar://58528686
Differential Revision: https://reviews.llvm.org/D73303
Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
This patch has a couple of outstanding issues. The test is not python3
compatible, and it also seems to fail with python2 (at least under some
circumstances) due to an overambitious assertion.
This reverts the patch as well as subsequent fixup attempts:
014ea93376,
f5f70d1c8f.
4697e701b8.
5c15e8e682.
3ec28da6d6.
When a thread stops, this checks depending on the platform if the top frame is
an abort stack frame. If so, it looks for an assert stack frame in the upper
frames and set it as the most relavant frame when found.
To do so, the StackFrameRecognizer class holds a "Most Relevant Frame" and a
"cooked" stop reason description. When the thread is about to stop, it checks
if the current frame is recognized, and if so, it fetches the recognized frame's
attributes and applies them.
rdar://58528686
Differential Revision: https://reviews.llvm.org/D73303
Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
Value::GetValueByteSize() reports the size of a Value as the size of its
underlying CompilerType. However, a host buffer that backs a Value may
be smaller than GetValueByteSize().
This situation arises when the host is only able to partially evaluate a
Value, e.g. because the expression contains DW_OP_piece.
The cleanest fix I've found to this problem is Greg's suggestion, which
is to resize the Value if (after evaluating an expression) it's found to
be too small. I've tried several alternatives which all (in one way or
the other) tried to teach the Value/ValueObjectChild system not to read
past the end of a host buffer, but this was flaky and impractical as it
isn't easy to figure out the host buffer's size (Value::GetScalar() can
point to somewhere /inside/ a host buffer, but you need to walk up the
ValueObject hierarchy to try and find its size).
This fixes an ASan error in lldb seen when debugging a clang binary.
I've added a regression test in test/functionalities/optimized_code. The
point of that test is not specifically to check that DW_OP_piece is
handled a particular way, but rather to check that lldb doesn't crash on
an input that it used to crash on.
Testing: check-lldb, and running the added tests using a sanitized lldb
--
Thanks to Jim for pointing out that an earlier version of this patch,
which simply changed the definition of Value::GetValueByteSize(), would
interact poorly with the ValueObject machinery.
Thanks also to Pavel who suggested a neat way to test this change
(which, incidentally, caught another ASan issue still present in the
original version of this patch).
rdar://58665925
Differential Revision: https://reviews.llvm.org/D73148
The CMakeLists.txt had a typo which meant that check-lldb-repro was
capturing twice instead of capturing and then replaying. This also
uncovered a missing import in lldb-repro.py. This patch fixes both
issues.
This commit adds AVR support to lldb. With this change, it can load a
binary and do basic things like dump a line table.
Not much else has been implemented, that should be done in later
changes.
Differential Revision: https://reviews.llvm.org/D73539
When a thread stops, this checks depending on the platform if the top frame is
an abort stack frame. If so, it looks for an assert stack frame in the upper
frames and set it as the most relavant frame when found.
To do so, the StackFrameRecognizer class holds a "Most Relevant Frame" and a
"cooked" stop reason description. When the thread is about to stop, it checks
if the current frame is recognized, and if so, it fetches the recognized frame's
attributes and applies them.
rdar://58528686
Differential Revision: https://reviews.llvm.org/D73303
Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
This reverts commit 1b12766883 because of
breaking the mac test suite.
I'm not certain this is the cause because of a concurrent build breakage
which masked this problem, but the failure messages are related to
symbol lookup, which makes this very likely.
Summary:
In the spirit of https://reviews.llvm.org/D70846, we only return functions with matching mangled name from Apple/DebugNamesDWARFIndex::GetFunction if eFunctionNameTypeFull is requested.
This speeds up lookup in the presence of large amount of class methods of the same name (a typical examples would be constructors of templates with many instantiations or overloaded operators).
Reviewers: labath
Reviewed By: labath
Subscribers: aprantl, arphaman, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D73191
Explicitly disallow using lldb instead of %lldb in the shell tests. This
is a clever trick that is used by Swift to achieve the same results.
Differential revision: https://reviews.llvm.org/D73289
We were incorrectly parsing the -C argument to breakpoint set as the
column breakpoint, even though according to the help this should be the
breakpoint command. This fixes that by renaming the option to -u, adding
it to help, and adding a test case.
Differential revision: https://reviews.llvm.org/D73284
As explained in Pavel's previous commit message: %lldb is the proper
substitution. Using "lldb" can cause us to execute the system lldb
instead of the one we are testing. This happens at least in standalone
builds.
This causes the toplevel "test-depends" target, which should only build
all the dependencies necessary for running tests, to suddenaly also run
the check-lldb-repro-capture tests.
Instead add check-lldb-repro-capture as a dependency to check-lldb-repro
with a separate explicit add_dependencies call.
This adds a new target check-lldb-repro which runs the shell tests with
the lldb-repo utility. It runs the shell tests twice, once while
capturing a reproducer and then again by replaying that reproducer.
These test are checking for diagnostics printed by the driver. During
replay we only replay the SB API calls made by the driver, so it's
expected that these messages aren't displayed.
The reproducers currently only shadow the command interpreter. It would
be possible to make it work for the Lua interpreter which uses the
IOHandlerEditline under the hood, but the Python one runs a REPL in
Python itself so there's no (straightforward) way to shadow that.
Given that we already capture any API calls, this isn't super high on my
list of priorities.
%lldb is the proper substitution. Using "lldb" can cause us to execute
the system lldb instead of the one we are testing. This happens at least
in standalone builds.
The Xcode generator does not provide the auto-generated targets where
you can append a folder name to check-lldb. Instead add two custom lit
targets to run just the shell and api tests.
This patch introduces a small new utility (lldb-repro) to transparently
capture and replay debugger sessions through the command line driver.
Its used to test the reproducers by running the test suite twice.
During the first run, it captures a reproducer for every lldb invocation
and saves it to a well-know location derived from the arguments and
current working directory. During the second run, the test suite is run
again but this time every invocation of lldb replays the previously
recorded session.
Differential revision: https://reviews.llvm.org/D72823
Summary:
Normally, on linux we retrieve the process ID from the LinuxProcStatus
stream (which is just the contents of /proc/%d/status pseudo-file).
However, this stream is not strictly required (it's a breakpad
extension), and we are encountering a fair amount of minidumps which do
not have it present. It's not clear whether this is the case with all
these minidumps, but the two known situations where this stream can be
missing are:
- /proc filesystem not mounted (or something to that effect)
- process crashing after exhausting (almost) all file descriptors (so
the minidump writer may not be able to open the /proc file)
Since this is a corner case which will become less and less relevant
(crashpad-generated minidumps should not suffer from this problem), I
work around this problem by hardcoding the PID to 1 in these cases.
The same thing is done by the gdb plugin when talking to a stub which
does not report a process id (e.g. a hardware probe).
Reviewers: jingham, clayborg
Subscribers: markmentovai, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D70238
Summary:
The goal of this patch is two-fold. First, it fixes a use-after-free in
the construction of the llvm DWARFContext. This happened because the
construction code was throwing away the lldb DataExtractors it got while
reading the sections (unlike their llvm counterparts, these are also
responsible for memory ownership). In most cases this did not matter,
because the sections are just slices of the mmapped file data. But this
isn't the case for compressed elf sections, in which case the section is
decompressed into a heap buffer. A similar thing also happen with object
files which are loaded from process memory.
The second goal is to make it explicit which sections go into the llvm
DWARFContext -- any access to the sections through both DWARF parsers
carries a risk of parsing things twice, so it's better if this is a
conscious decision. Also, this avoids loading completely irrelevant
sections (e.g. .text). At present, the only section that needs to be
present in the llvm DWARFContext is the debug_line_str. Using it through
both APIs is not a problem, as there is no parsing involved.
The first goal is achieved by loading the sections through the existing
lldb DWARFContext APIs, which already do the caching. The second by
explicitly enumerating the sections we wish to load.
Reviewers: JDevlieghere, aprantl
Subscribers: lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D72917
These tests used "clang -mllvm -accel-tables=Dwarf" as a way to
guarantee that clang will emit the debug_names table. Unfortunately,
a change it clang made that insufficient (-gpubnames is required now
too), which rendered these tests ineffective. Since lldb automatically
falls back to the manual index, the tests didn't fail and this change
went largely unnoticed.
This patch updates the tests to really use debug_names (-gdwarf-5
-gpubnames) is the combination that works now, and it adds additional
checks to ensure the section is actually emitted.
Fortunately, no regressions crept in while these tests were disabled.
Add a flag which always generates a reproducer when normally it would be
discarded. This is meant for testing purposes to capture a debugger
session without modification the session itself.
Summary:
This is the first in a series of patches to enable LLDB debugging of
WebAssembly targets.
Current versions of Clang emit (partial) DWARF debug information in WebAssembly
modules and we can leverage this debug information to give LLDB the ability to
do source-level debugging of Wasm code that runs in a WebAssembly engine.
A way to do this could be to use the remote debugging functionalities provided
by LLDB via the GDB-remote protocol. Remote debugging can indeed be useful not
only to connect a debugger to a process running on a remote machine, but also to
connect the debugger to a managed VM or script engine that runs locally,
provided that the engine implements a GDB-remote stub that offers the ability to
access the engine runtime internal state.
To make this work, the GDB-remote protocol would need to be extended with a few
Wasm-specific custom query commands, used to access aspects of the Wasm engine
state (like the Wasm memory, Wasm local and global variables, and so on).
Furthermore, the DWARF format would need to be enriched with a few Wasm-specific
extensions, here detailed: https://yurydelendik.github.io/webassembly-dwarf.
This CL introduce classes **ObjectFileWasm**, a file plugin to represent a Wasm
module loaded in a debuggee process. It knows how to parse Wasm modules and
store the Code section and the DWARF-specific sections.
Reviewers: jasonmolenda, clayborg, labath
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D71575
These are the last sections not managed by the DWARFContext object. I
also introduce separate SectionType enums for dwo section variants, as
this is necessary for proper handling of single-file split dwarf.
Summary:
This change is connected with
https://reviews.llvm.org/D69843
In large codebases, we sometimes see Module::FindFunctions (when called from
ClangExpressionDeclMap::FindExternalVisibleDecls) returning huge amounts of
functions.
In current fix I trying to return only function_fullnames from ManualDWARFIndex::GetFunctions when eFunctionNameTypeFull is passed as argument.
Reviewers: labath, jarin, aprantl
Reviewed By: labath
Subscribers: shafik, clayborg, teemperor, arphaman, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D70846
This fixes a failing testcase on Fedora 30 x86_64 (regression Fedora 29->30):
PASS:
./bin/lldb ./lldb-test-build.noindex/functionalities/unwind/noreturn/TestNoreturnUnwind.test_dwarf/a.out -o 'settings set symbols.enable-external-lookup false' -o r -o bt -o quit
* frame #0: 0x00007ffff7aa6e75 libc.so.6`__GI_raise + 325
frame #1: 0x00007ffff7a91895 libc.so.6`__GI_abort + 295
frame #2: 0x0000000000401140 a.out`func_c at main.c:12:2
frame #3: 0x000000000040113a a.out`func_b at main.c:18:2
frame #4: 0x0000000000401134 a.out`func_a at main.c:26:2
frame #5: 0x000000000040112e a.out`main(argc=<unavailable>, argv=<unavailable>) at main.c:32:2
frame #6: 0x00007ffff7a92f33 libc.so.6`__libc_start_main + 243
frame #7: 0x000000000040106e a.out`_start + 46
vs.
FAIL - unrecognized abort() function:
./bin/lldb ./lldb-test-build.noindex/functionalities/unwind/noreturn/TestNoreturnUnwind.test_dwarf/a.out -o 'settings set symbols.enable-external-lookup false' -o r -o bt -o quit
* frame #0: 0x00007ffff7aa6e75 libc.so.6`.annobin_raise.c + 325
frame #1: 0x00007ffff7a91895 libc.so.6`.annobin_loadmsgcat.c_end.unlikely + 295
frame #2: 0x0000000000401140 a.out`func_c at main.c:12:2
frame #3: 0x000000000040113a a.out`func_b at main.c:18:2
frame #4: 0x0000000000401134 a.out`func_a at main.c:26:2
frame #5: 0x000000000040112e a.out`main(argc=<unavailable>, argv=<unavailable>) at main.c:32:2
frame #6: 0x00007ffff7a92f33 libc.so.6`.annobin_libc_start.c + 243
frame #7: 0x000000000040106e a.out`.annobin_init.c.hot + 46
The extra ELF symbols are there due to Annobin (I did not investigate why this
problem happened specifically since F-30 and not since F-28).
It is due to:
Symbol table '.dynsym' contains 2361 entries:
Valu e Size Type Bind Vis Name
0000000000022769 5 FUNC LOCAL DEFAULT _nl_load_domain.cold
000000000002276e 0 NOTYPE LOCAL HIDDEN .annobin_abort.c.unlikely
...
000000000002276e 0 NOTYPE LOCAL HIDDEN .annobin_loadmsgcat.c_end.unlikely
...
000000000002276e 0 NOTYPE LOCAL HIDDEN .annobin_textdomain.c_end.unlikely
000000000002276e 548 FUNC GLOBAL DEFAULT abort
000000000002276e 548 FUNC GLOBAL DEFAULT abort@@GLIBC_2.2.5
000000000002276e 548 FUNC LOCAL DEFAULT __GI_abort
0000000000022992 0 NOTYPE LOCAL HIDDEN .annobin_abort.c_end.unlikely
GDB has some more complicated preferences between overlapping and/or sharing
address symbols, I have made here so far the most simple fix for this case.
Differential revision: https://reviews.llvm.org/D63540
lld in 2bfee35 started emitting relocations for some intra-section jumps
between global symbols. This shifted the code around a bit, invalidating
text expectations.
Change the symbols to local to keep the previous behavior.
The Python script interpreter makes the current debugger, target,
process, thread and frame available to interactive scripting sessions
through convenience variables. This patch does the same for Lua.
Differential revision: https://reviews.llvm.org/D71801
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
In TestConvenienceVariables I changed %t from a file to a directory.
This tripped up mkdir which can't deal with an existing file at the
given location. In order to solve this issue on the bots I added an
`rm -rf %t` statement, but now the Windows bot complains that "This
function is not supported on this system".
If you never ran the test suite wit this temporary workaround, the test
might fail. If this happens please remove what %t expands to in the lit
output and rerun the test.
This test was passing even when the output of lldb.target was empty.
I've made the test more strict by checking explicitly for the target
name and by using CHECK-NEXT lines.
The test was being skipped on the Windwos bot because it requires Python
which was silently disabled because of a configuration issue. Now that
the test runs, this fails as expected.
This bit of code is trying to strip everything up to the first colon
from all debug info paths, as dwarf2 recommends this syntax for storing
the compilation host name. However, this code was too eager, and it
ended up stripping the entire compilation directory, if it did not
contain a forward slash (or a "x:\").
Normally this does not matter, as all absolute paths will contain one of
these patterns, but this does not have to be the case in case the debug
info is produced by "clang -fdebug-compilation-dir", which can end up
producing a relative compilation directory with no slashes (this is one
of the techniques for producing "relocatable" debug info).
This ensures that breakpoint command honors the scripting language
passed with `-s`. Currently the argument ignores the actual language and
only uses it to differentiate between lldb and script commands.
Don't create a new lua state on every operation. Share a single state
across the lifetime of the script interpreter. Add simple locking to
prevent two threads from modifying the state concurrently.
D71372 introduced: `Unwind/thread-step-out-ret-addr-check.test` failing on
Fedora 30 Linux x86_64.
[lldb] Add additional validation on return address in 'thread step-out'
https://reviews.llvm.org/D71372
One problem is the underscored `_nonstandard_stub` in the `.s` file but not in
the LLDB command:
(lldb) breakpoint set -n nonstandard_stub
Breakpoint 1: no locations (pending).
WARNING: Unable to resolve breakpoint to any actual locations.
(lldb) process launch
Process 21919 exited with status = 0 (0x00000000)
Process 21919 launched: '/home/jkratoch/redhat/llvm-monorepo-clangassert/tools/lldb/test/Unwind/Output/thread-step-out-ret-addr-check.test.tmp' (x86_64)
(lldb) thread step-out
error: invalid thread
(lldb) _
Another problem is that Fedora Linux has executable stack by default and all
programs indicate non-executable stack by `PT_GNU_STACK`, after fixing the
underscore I was getting:
(lldb) thread step-out
Process 22294 exited with status = 0 (0x00000000)
(lldb) _
A different approach was tried as:
[lldb] Refactor thread-step-out-ret-addr-check test to use .data instead of stack variable
https://reviews.llvm.org/D71789
Differential revision: https://reviews.llvm.org/D71784
This implements a very elementary Lua script interpreter. It supports
running a single command as well as running interactively. It uses
editline if available. It's still missing a bunch of stuff though. Some
things that I intentionally ingored for now are that I/O isn't properly
hooked up (so every print goes to stdout) and the non-editline support
which is not handling a bunch of corner cases. The latter is a matter of
reusing existing code in the Python interpreter.
Discussion on the mailing list:
http://lists.llvm.org/pipermail/lldb-dev/2019-December/015812.html
Differential revision: https://reviews.llvm.org/D71234
Previously, if the current function had a nonstandard stack layout/ABI, and had a valid
data pointer in the location where the return address is usually located, data corruption
would occur when the breakpoint was written. This could lead to an incorrectly reported
crash or silent corruption of the program's state. Now, if the above check fails, the command safely aborts.
Differential Revision: https://reviews.llvm.org/D71372
Summary:
Fixes PR41237 - SIGSEGV on call expression evaluation when debugging clang
When linking multiple compilation units that define the same functions,
the functions is merged but their debug info is not. This ignores debug
info entries for functions in a non-executable sections; those are
functions that were definitely dropped by the linker.
Reviewers: spyffe, clayborg, jasonmolenda
Reviewed By: clayborg
Subscribers: labath, aprantl, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D71487
Create a new test for lldb launched without a script interpreter and
move it under a new `ScriptInterpreter` directory. Also move
crashlog.test there for consistency.
Summary:
Add `function.mangled-name` key for FormatEntity to show the mangled
function names in backtraces.
rdar://54088244
Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
Subscribers: lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D71237
Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
Summary:
This enables us to display the contents of atomic structs. Calling the
removal of _Atomic "desugaring" is not fully correct as it does more
than remove sugar, but it is the right thing to do for most of the
things that we care about. We can change this back once we decide to
support atomic types more comprehensively.
Reviewers: teemperor, shafik
Subscribers: jfb, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D71262
Summary:
This adds support for DWARF5 location lists which are specified
indirectly, via an index into the debug_loclists offset table. This
includes parsing the DW_AT_loclists_base attribute which determines the
location of this offset table, and support for new form DW_FORM_loclistx
which is used in conjuction with DW_AT_location to refer to the location
lists in this way.
The code uses the llvm class to parse the offset information, and I've
also tried to structure it similarly to how the relevant llvm
functionality works.
Reviewers: JDevlieghere, aprantl, clayborg
Subscribers: lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D71268
When running the test suite with always capture on, a handful of tests
are failing because they have multiple targets and therefore multiple
GDB remote connections. The current reproducer infrastructure is capable
of dealing with that.
This patch reworks the GDB remote provider to support multiple GDB
remote connections, similar to how the reproducers support shadowing
multiple command interpreter inputs. The provider now keeps a list of
packet recorders which deal with a single GDB remote connection. During
replay we rely on the order of creation to match the number of packets
to the GDB remote connection.
Differential revision: https://reviews.llvm.org/D71105
Summary:
This patch deletes the lldb location list parser and teaches the
DWARFExpression class to use the parser in llvm instead. I have
centralized all the places doing the parsing into a single
GetLocationExpression function.
In theory the the actual location list parsing should be covered by llvm
tests, and this glue code by our existing location list tests, but since
we don't have that many location list tests, I've tried to extend the
coverage a bit by adding some explicit dwarf5 loclist handling and a
test of the dumping code.
For DWARF4 location lists this should be NFC (modulo small differences
in error handling which should only show up on invalid inputs). In case
of DWARF5, this fixes various missing bits of functionality, most
notably, the lack of support for DW_LLE_offset_pair.
Reviewers: JDevlieghere, aprantl, clayborg
Subscribers: lldb-commits, dblaikie
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D71003
Summary:
Lldb support base address selection entries in location lists was broken
for a long time. This wasn't noticed until llvm started producing these
kinds of entries more frequently with r374600.
In r374769, I made a quick patch which added sufficient support for them
to get the test suite to pass. However, I did not fully understand how
this code operates, and so the fix was not complete. Specifically, what
was lacking was the ability to handle modules which were not loaded at
their preferred load address (for instance, due to ASLR).
Now that I better understand how this code works, I've come to the
conclusion that the current setup does not provide enough information
to correctly process these entries. In the current setup the location
lists were parameterized by two addresses:
- the distance of the function start from the start of the compile unit.
The purpose of this was to make the location ranges relative to the
start of the function.
- the actual address where the function was loaded at. With this the
function-start-relative ranges can be translated to actual memory
locations.
The reason for the two values, instead of just one (the load bias) is (I
think) MachO, where the debug info in the object files will appear to be
relative to the address zero, but the actual code it refers to
can be moved and reordered by the linker. This means that the location
lists need to be "linked" to reflect the locations in the actual linked
file.
These two bits of information were enough to correctly process location
lists which do not contain base address selection entries (and so all
entries are relative to the CU base). However, they don't work with
them because, in theory two base address can be completely unrelated (as
can happen for instace with hot/cold function splitting, where the
linker can reorder the two pars arbitrarily).
To fix that, I split the first parameter into two:
- the compile unit base address
- the function start address, as is known in the object file
The new algorithm becomes:
- the location lists are processed as they were meant to be processed.
The CU base address is used as the initial base address value. Base
address selection entries can set a new base.
- the difference between the "file" and "load" function start addresses
is used to compute the load bias. This value is added to the final
ranges to get the actual memory location.
This algorithm is correct for non-MachO debug info, as there the
location lists correctly describe the code in the final executable, and
the dynamic linker can just move the entire module, not pieces of it. It
will also be correct for MachO if the static linker preserves relative
positions of the various parts of the location lists -- I don't know
whether it actually does that, but judging by the lack of base address
selection support in dsymutil and lldb, this isn't something that has
come up in the past.
I add a test case which simulates the ASLR scenario and demonstrates
that base address selection entries now work correctly here.
Reviewers: JDevlieghere, aprantl, clayborg
Subscribers: dblaikie, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D70532
Summary:
This patch adds support for atomic types (DW_TAG_atomic_type) to LLDB. It's mostly just filling out all the switch-statements that didn't implement Atomic case with the usual boilerplate.
Thanks Pavel for writing the test case.
Reviewers: labath, aprantl, shafik
Reviewed By: labath
Subscribers: jfb, abidh, JDevlieghere, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D71183
In DWARF5 DW_AT_low_pc (and DW_AT_entry_pc, and possibly others) can use
DW_FORM_addrx to refer to the address indirectly. This means we need to
have processed the DW_AT_addr_base attribute before we can do anything
with these.
Since we were processing the unit attributes serially, this created a
problem in cases where the DW_AT_addr_base comes after DW_AT_low_pc --
we would end up computing the wrong unit base address, which also
corrupted any values which later depended on that (for instance range
lists). Clang currently always emits DW_AT_addr_base last.
The fix is simple -- process DW_AT_addr_base first, regardless of its
position in the attribute list.
the value of DW_AT_rnglists_base of the skeleton unit is for that unit
alone (e.g. used in DW_AT_ranges of the unit DIE) and should not apply
to the split unit.
The split unit has a hardcoded range list base value -- we should
initialize range list code whenever we detect a nonempty
debug_rnglists.dwo section.
Summary:
Our rnglist support was working only for the trivial cases (one CU),
because we only ever parsed one contribution out of the debug_rnglists
section. This means we were never able to resolve range lists for the
second and subsequent units (DW_FORM_sec_offset references came out
blang, and DW_FORM_rnglistx references always used the ranges lists from
the first unit).
Since both llvm and lldb rnglist parsers are sufficiently
self-contained, and operate similarly, we can fix this problem by
switching to the llvm parser instead. Besides the changes which are due
to variations in the interface, the main thing is that now the range
list object is a member of the DWARFUnit, instead of the entire symbol
file. This ensures that each unit can get it's own private set of range
list indices, and is consistent with how llvm's DWARFUnit does it
(overall, I've tried to structure the code the same way as the llvm
version).
I've also added a test case for the two unit scenario.
Reviewers: JDevlieghere, aprantl, clayborg
Subscribers: dblaikie, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D71021
Summary:
Lldb's "format-independent" debug info made use of the fact that DWARF
(<=4) did not use the file index zero, and reused the support file index
zero for storing the compile unit name.
While this provided some convenience for DWARF<=4, it meant that the PDB
plugin needed to artificially remap file indices in order to free up
index 0. Furthermore, DWARF v5 make file index 0 legal, which meant that
similar remapping would be needed in the dwarf plugin too.
What this patch does instead is remove the requirement of having the
compile unit name in the index 0. It is not that useful since the name
can always be fetched from the CompileUnit object. Remapping code in the
pdb plugin(s) has been removed or simplified.
DWARF plugin has started inserting an empty FileSpec at index 0 to
ensure the indices keep matching up (in case of DWARF<=4). For DWARF5,
we insert the file 0 from the line table.
I add a test to ensure we can correctly lookup line table entries
referencing file 0, and in particular the case where the file 0 is also
duplicated in another file entry, as this is how clang produces line
tables in some circumstances (see pr44170). Though this is probably a
bug in clang, this is not forbidden by DWARF, and lldb already has
support for that in some (but not all) cases -- this adds a test for the
code path which was not fixed in this patch.
Reviewers: clayborg, JDevlieghere, jdoerfert
Subscribers: aprantl, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D70954
Jason Molenda