A trace might contain events traced during the target's execution. For
example, a thread might be paused for some period of time due to context
switches or breakpoints, which actually force a context switch. Not only
that, a trace might be paused because the CPU decides to trace only a
specific part of the target, like the address filtering provided by
intel pt, which will cause pause events. Besides this case, other kinds
of events might exist.
This patch adds the method `TraceCursor::GetEvents()`` that returns the
list of events that happened right before the instruction being pointed
at by the cursor. Some refactors were done to make this change simpler.
Besides this new API, the instruction dumper now supports the -e flag
which shows pause events, like in the following example, where pauses
happened due to breakpoints.
```
thread #1: tid = 2717361
a.out`main + 20 at main.cpp:27:20
0: 0x00000000004023d9 leaq -0x1200(%rbp), %rax
[paused]
1: 0x00000000004023e0 movq %rax, %rdi
[paused]
2: 0x00000000004023e3 callq 0x403a62 ; std::vector<int, std::allocator<int> >::vector at stl_vector.h:391:7
a.out`std::vector<int, std::allocator<int> >::vector() at stl_vector.h:391:7
3: 0x0000000000403a62 pushq %rbp
4: 0x0000000000403a63 movq %rsp, %rbp
```
The `dump info` command has also been updated and now it shows the
number of instructions that have associated events.
Differential Revision: https://reviews.llvm.org/D123982
I'm adding two new classes that can be used to measure the duration of long
tasks as process and thread level, e.g. decoding, fetching data from
lldb-server, etc. In this first patch, I'm using it to measure the time it takes
to decode each thread, which is printed out with the `dump info` command. In a
later patch I'll start adding process-level tasks and I might move these
classes to the upper Trace level, instead of having them in the intel-pt
plugin. I might need to do that anyway in the future when we have to
measure HTR. For now, I want to keep the impact of this change minimal.
With it, I was able to generate the following info of a very big trace:
```
(lldb) thread trace dump info Trace technology: intel-pt
thread #1: tid = 616081
Total number of instructions: 9729366
Memory usage:
Raw trace size: 1024 KiB
Total approximate memory usage (excluding raw trace): 123517.34 KiB
Average memory usage per instruction (excluding raw trace): 13.00 bytes
Timing:
Decoding instructions: 1.62s
Errors:
Number of TSC decoding errors: 0
```
As seen above, it took 1.62 seconds to decode 9.7M instructions. This is great
news, as we don't need to do any optimization work in this area.
Differential Revision: https://reviews.llvm.org/D123357
In order to support quick arbitrary access to instructions in the trace, we need
each instruction to have an id. It could be an index or any other value that the
trace plugin defines.
This will be useful for reverse debugging or for creating callstacks, as each
frame will need an instruction id associated with them.
I've updated the `thread trace dump instructions` command accordingly. It now
prints the instruction id instead of relative offset. I've also added a new --id
argument that allows starting the dump from an arbitrary position.
Differential Revision: https://reviews.llvm.org/D122254
Since the threads/frame view is taking only a small part on the right side
of the screen, only a part of the function name of each frame is visible.
It seems rather wasteful to spell out 'frame' there when it's obvious
that it is a frame, it's better to use the space for more of the function
name.
Differential Revision: https://reviews.llvm.org/D122998
It's rather annoying if it's there after every startup,
and that 'Help (F6)' at the top should be enough to help people
who don't know.
Differential Revision: https://reviews.llvm.org/D122997
A problem that I introduced in the decoder is that I was considering TSC decoding
errors as actual instruction errors, which mean that the trace has a gap. This is
wrong because a TSC decoding error doesn't mean that there's a gap in the trace.
Instead, now I'm just counting how many of these errors happened and I'm using
the `dump info` command to check for this number.
Besides that, I refactored the decoder a little bit to make it simpler, more
readable, and to handle TSCs in a cleaner way.
Differential Revision: https://reviews.llvm.org/D122867
Storing timestamps (TSCs) in a more efficient map at the decoded thread level to speed up TSC lookup, as well as reduce the amount of memory used by each decoded instruction. Also introduced TSC range which keeps the current timestamp valid for all subsequent instructions until the next timestamp is emitted.
Differential Revision: https://reviews.llvm.org/D122603
Protecting against accidental overwriting of commands is good, but
having to pass a flag to overwrite the command when developing your
commands is pretty annoying. This adds a setting to defeat the protection
so you can do this once at the start of your session and not have to
worry about it again.
Differential Revision: https://reviews.llvm.org/D122680
Now the decoded thread has Append methods that provide more flexibility
in terms of the underlying data structure that represents the
instructions. In this case, we are able to represent the sporadic errors
as map and thus reduce the size of each instruction.
Differential Revision: https://reviews.llvm.org/D122293
There's a bug caused when a process is relaunched: the target, which
doesn't change, keeps the Trace object from the previous process, which
is already defunct, and causes segmentation faults when it's attempted
to be used.
A fix is to clean up the Trace object when the target is disposing of
the previous process during relaunches.
A way to reproduce this:
```
lldb a.out
b main
r
process trace start
c
r
process trace start
```
Differential Revision: https://reviews.llvm.org/D122176
Added a line to `thread trace dump info` results which shows total number of instructions executed until now.
Differential Revision: https://reviews.llvm.org/D122076
Minor fixes needed and now `./bin/lldb-dotest -p TestTrace` passes
correctly.
- There was an incorrect iteration.
- Some error messages changed.
- The way repeat commands are handled changed a bit, so I had to create
a new --continue arg in "thread trace dump instructions" to handle this
correctly.
Differential Revision: https://reviews.llvm.org/D122023
Add a --exists/-e flag to `settings set` that sets the setting if it
exists, but doesn't print an error otherwise. This is useful for example
when setting options in your ~/.lldbinit that might not exist in older
versions of lldb.
Differential revision: https://reviews.llvm.org/D121155
The old command wrote to CWD, which doesn't always work, and if it
didn't, there was no workaround (and it crashed on failure). This
patch changed the setting to provide a directory to save the objects
to.
Differential Revision: https://reviews.llvm.org/D121036
lldb reports (and lldbutil.continue_to_breakpoint returns) a stop reason
even for suspended threads. Fix the test to expect that.
This was making the test flaky, as most of the time, the two threads
stop simultaneously, and the synchronization code is not executed.
One of the tests in this test setup was copied from a more complex test, and I didn't know
if the setup or the subsequent parts of the test were the ones that fail on Linux. Looks
like it was the latter, so let's mark this succeeding.
This way if you have a long stack, you can issue "thread backtrace --count 10"
and then subsequent <Return>-s will page you through the stack.
This took a little more effort than just adding the repeat command, since
the GetRepeatCommand API was returning a "const char *". That meant the command
had to keep the repeat string alive, which is inconvenient. The original
API returned either a nullptr, or a const char *, so I changed the private API to
return an llvm::Optional<std::string>. Most of the patch is propagating that change.
Also, there was a little thinko in fetching the repeat command. We don't
fetch repeat commands for commands that aren't being added to history, which
is in general reasonable. And we don't add repeat commands to the history -
also reasonable. But we do want the repeat command to be able to generate
the NEXT repeat command. So I adjusted the logic in HandleCommand to work
that way.
Differential Revision: https://reviews.llvm.org/D119046
Replace forms of `assertTrue(err.Success())` with `assertSuccess(err)` (added in D82759).
* `assertSuccess` prints out the error's message
* `assertSuccess` expresses explicit higher level semantics, both to the reader and for test failure output
* `assertSuccess` seems not to be well known, using it where possible will help spread knowledge
* `assertSuccess` statements are more succinct
Differential Revision: https://reviews.llvm.org/D119616
This mainly affects Darwin targets (macOS, iOS, tvOS and watchOS) when these targets don't use dSYM files and the debug info was in the .o files. All modules, including the .o files that are loaded by the debug maps, were in the global module list. This was great because it allows us to see each .o file and how much it contributes. There were virtual functions on the SymbolFile class to fetch the symtab/debug info parse and index times, and also the total debug info size. So the main executable would add all of the .o file's stats together and report them as its own data. Then the "totalDebugInfoSize" and many other "totalXXX" top level totals were all being added together. This stems from the fact that my original patch only emitted the modules for a target at the start of the patch, but as comments from the reviews came in, we switched to emitting all of the modules from the global module list.
So this patch fixes it so when we have a SymbolFileDWARFDebugMap that loads .o files, the main executable will have no debug info size or symtab/debug info parse/index times, but each .o file will have its own data as a separate module. Also, to be able to tell when/if we have a dSYM file I have added a "symbolFilePath" if the SymbolFile for the main modules path doesn't match that of the main executable. We also include a "symbolFileModuleIdentifiers" key in each module if the module does have multiple lldb_private::Module objects that contain debug info so that you can track down the information for a module and add up the contributions of all of the .o files.
Tests were added that are labeled with @skipUnlessDarwin and @no_debug_info_test that test all of this functionality so it doesn't regress.
For a module with a dSYM file, we can see the "symbolFilePath" is included:
```
"modules": [
{
"debugInfoByteSize": 1070,
"debugInfoIndexLoadedFromCache": false,
"debugInfoIndexSavedToCache": false,
"debugInfoIndexTime": 0,
"debugInfoParseTime": 0,
"identifier": 4873280600,
"path": "/Users/gclayton/Documents/src/lldb/main/Debug/lldb-test-build.noindex/commands/statistics/basic/TestStats.test_dsym_binary_has_symfile_in_stats/a.out",
"symbolFilePath": "/Users/gclayton/Documents/src/lldb/main/Debug/lldb-test-build.noindex/commands/statistics/basic/TestStats.test_dsym_binary_has_symfile_in_stats/a.out.dSYM/Contents/Resources/DWARF/a.out",
"symbolTableIndexTime": 7.9999999999999996e-06,
"symbolTableLoadedFromCache": false,
"symbolTableParseTime": 7.8999999999999996e-05,
"symbolTableSavedToCache": false,
"triple": "arm64-apple-macosx12.0.0",
"uuid": "E1F7D85B-3A42-321E-BF0D-29B103F5F2E3"
},
```
And for the DWARF in .o file case we can see the "symbolFileModuleIdentifiers" in the executable's module stats:
```
"modules": [
{
"debugInfoByteSize": 0,
"debugInfoIndexLoadedFromCache": false,
"debugInfoIndexSavedToCache": false,
"debugInfoIndexTime": 0,
"debugInfoParseTime": 0,
"identifier": 4603526968,
"path": "/Users/gclayton/Documents/src/lldb/main/Debug/lldb-test-build.noindex/commands/statistics/basic/TestStats.test_no_dsym_binary_has_symfile_identifiers_in_stats/a.out",
"symbolFileModuleIdentifiers": [
4604429832
],
"symbolTableIndexTime": 7.9999999999999996e-06,
"symbolTableLoadedFromCache": false,
"symbolTableParseTime": 0.000112,
"symbolTableSavedToCache": false,
"triple": "arm64-apple-macosx12.0.0",
"uuid": "57008BF5-A726-3DE9-B1BF-3A9AD3EE8569"
},
```
And the .o file for 4604429832 looks like:
```
{
"debugInfoByteSize": 1028,
"debugInfoIndexLoadedFromCache": false,
"debugInfoIndexSavedToCache": false,
"debugInfoIndexTime": 0,
"debugInfoParseTime": 6.0999999999999999e-05,
"identifier": 4604429832,
"path": "/Users/gclayton/Documents/src/lldb/main/Debug/lldb-test-build.noindex/commands/statistics/basic/TestStats.test_no_dsym_binary_has_symfile_identifiers_in_stats/main.o",
"symbolTableIndexTime": 0,
"symbolTableLoadedFromCache": false,
"symbolTableParseTime": 0,
"symbolTableSavedToCache": false,
"triple": "arm64-apple-macosx"
}
```
Differential Revision: https://reviews.llvm.org/D119400
Add statistics about the memory usage of the string pool. I'm
particularly interested in the memory used by the allocator, i.e. the
number of bytes actually used by the allocator it self as well as the
number of bytes allocated through the allocator.
Differential revision: https://reviews.llvm.org/D117914
Allow users to create aliases for aliases to raw input commands. That probably
sounds convoluted, so here's an example:
```
command alias some-setup env SOMEVAR=SOMEVALUE
```
This an alias based on `env`, which itself is an alias for `_regex-env`.
`_regex-env` is a `command regex` command, which takes raw input.
The above `some-setup` alias fails with:
```
error: Unable to create requested alias.
```
This change allows such aliases to be created. lldb already supports aliases to
aliases for parsed commands.
Differential Revision: https://reviews.llvm.org/D117259
"shell" is an alias to "platform shell -h --". Previously you would get this
help text:
(lldb) help shell
Run a shell command on the host. Expects 'raw' input (see 'help raw-input'.)
Syntax: shell <shell-command>
Command Options Usage:
'shell' is an abbreviation for 'platform shell -h --'
Since the code doesn't handle the base command having options
but the alias removing them. With these changes you get:
(lldb) help shell
Run a shell command on the host. Expects 'raw' input (see 'help raw-input'.)
Syntax: shell <shell-command>
'shell' is an abbreviation for 'platform shell -h --'
Note that we already handle a non-alias command having no options,
for example "quit":
(lldb) help quit
Quit the LLDB debugger.
Syntax: quit [exit-code]
Reviewed By: JDevlieghere, jingham
Differential Revision: https://reviews.llvm.org/D117004
Fixes incomplete command names in `apropos` results.
The full command names given by `apropos` have come from command name string
literals given to `CommandObject` constructors. For most commands, this has
been accurate, but some commands have incorrect strings. This results in
`apropos` output that doesn't tell the user the full command name they might
want learn more about. These strings can be fixed.
There's a seperate issue that can't be fixed as easily: plugin commands. With
the way they're implemented, plugin commands have to exclude the root command
from their command name string. To illustrate, the `language objc` subcommand
has to set its command name string to "objc", which results in apropos printing
results as `objc ...` instead of `language objc ...`.
To fix both of these issues, this commit changes `FindCommandsForApropos` to
derive the fully qualified command name using the keys of subcommand maps.
Differential Revision: https://reviews.llvm.org/D116491
(cherry picked from commit b3bfd595a548cd85b12e4e83729436cb73b26f29)
Unlike the rest of our SB objects, SBEvent and SBCommandReturnObject
have the ability to hold non-owning pointers to their non-SB
counterparts. This makes it hard to ensure the SB objects do not become
dangling once their backing object goes away.
While we could make these two objects behave like others, that would
require plubming even more shared pointers through our internal code
(Event objects are mostly prepared for it, CommandReturnObject are not).
Doing so seems unnecessarily disruptive, given that (unlike for some of
the other objects) I don't see any good reason why would someone want to
hold onto these objects after the function terminates.
For that reason, this patch implements a different approach -- the SB
objects will still hold non-owning pointers, but they will be reset to
the empty/default state as soon as the function terminates. This python
code will not crash if the user decides to store these objects -- but
the objects themselves will be useless/empty.
Differential Revision: https://reviews.llvm.org/D116162
This patch add the ability to cache the manual DWARF indexing results to disk for faster subsequent debug sessions. Manual DWARF indexing is time consuming and causes all DWARF to be fully parsed and indexed each time you debug a binary that doesn't have an acceptable accelerator table. Acceptable accelerator tables include .debug_names in DWARF5 or Apple accelerator tables.
This patch breaks up testing by testing all of the encoding and decoding of required C++ objects in a gtest unit test, and then has a test to verify the debug info cache is generated correctly.
This patch also adds the ability to track when a symbol table or DWARF index is loaded or saved to the cache in the "statistics dump" command. This is essential to know in statistics as it can help explain why a debug session was slower or faster than expected.
Reviewed By: labath, wallace
Differential Revision: https://reviews.llvm.org/D115951
This starts to fix the other half of the lifetime problems in this code
-- dangling references. SB objects created on the stack will go away
when the function returns, which is a problem if the python code they
were meant for stashes a reference to them somewhere. Most of the time
this goes by unnoticed, as the code rarely has a reason to store these,
but in case it does, we shouldn't respond by crashing.
This patch fixes the management for a couple of SB objects (Debugger,
Frame, Thread). The SB objects are now created on the heap, and
their ownership is immediately passed on to SWIG, which will ensure they
are destroyed when the last python reference goes away. I will handle
the other objects in separate patches.
I include one test which demonstrates the lifetime issue for SBDebugger.
Strictly speaking, one should create a test case for each of these
objects and each of the contexts they are being used. That would require
figuring out how to persist (and later access) each of these objects.
Some of those may involve a lot of hoop-jumping (we can run python code
from within a frame-format string). I don't think that is
necessary/worth it since the new wrapper functions make it very hard to
get this wrong.
Differential Revision: https://reviews.llvm.org/D115925
Also add tests to check that we print the warning in the right
circumstances.
Reviewed By: labath
Differential Revision: https://reviews.llvm.org/D114877
Certain commands like 'memory write', 'register read' etc all use
the OptionGroupFormat options but the help usage text for those
options is not customized to those commands.
One such example is:
(lldb) help memory read
-s <byte-size> ( --size <byte-size> )
The size in bytes to use when displaying with the selected format.
(lldb) help memory write
-s <byte-size> ( --size <byte-size> )
The size in bytes to use when displaying with the selected format.
This patch allows such commands to overwrite the help text for the options
in the OptionGroupFormat group as needed and fixes help text of memory write.
llvm.org/pr49018.
Reviewed By: DavidSpickett
Differential Revision: https://reviews.llvm.org/D114448
Currently the 'memory write' command allows specifying the values when
writing the file contents to memory but the values are actually ignored. This
patch fixes that by erroring out when values are specified in such cases.
Reviewed By: DavidSpickett
Differential Revision: https://reviews.llvm.org/D114544
It is great to know how many times the target has stopped over its lifetime as each time the target stops, and possibly resumes without the user seeing it for things like shared library loading and signals that are not notified and auto continued, to help explain why a debug session might be slow. This is now included as "stopCount" inside each target JSON.
Differential Revision: https://reviews.llvm.org/D113810
D112976 changed the layout and 0d62e31c45 andjusted the test
expectations to match.
This patch changes the tests to expect both versions, so that one can
run the test suite against older libc++ versions as well.
D112976 moved most of the guts of __vector_base into vector, this broke
some LLDB tests by changing the result types that LLDB sees. This updates
the test to reflect the new structure.
