The WatchAddress API includes a flag to indicate if watchpoint should be
for read, modify or both. This API uses 2 booleans, but the 'modify'
flag was ignored and WatchAddress unconditionally watched write
(actually modify).
We now only watch for modify when the modify flag is true.
---
The included test fails prior to this patch and succeeds after. That is
previously specifying `False` for `modify` would still stop on _write_,
but after the patch correctly only stops on _read_
This uses [teyit](https://pypi.org/project/teyit/) to modernize asserts,
as recommended by the [unittest release
notes](https://docs.python.org/3.12/whatsnew/3.12.html#id3).
For example, `assertTrue(a == b)` is replaced with `assertEqual(a, b)`.
This produces better error messages, e.g. `error: unexpectedly found 1
and 2 to be different` instead of `error: False`.
This patch is rearranging code a bit to add WatchpointResources to
Process. A WatchpointResource is meant to represent a hardware
watchpoint register in the inferior process. It has an address, a size,
a type, and a list of Watchpoints that are using this
WatchpointResource.
This current patch doesn't add any of the features of
WatchpointResources that make them interesting -- a user asking to watch
a 24 byte object could watch this with three 8 byte WatchpointResources.
Or a Watchpoint on 1 byte at 0x1002 and a second watchpoint on 1 byte at
0x1003, these must both be served by a single WatchpointResource on that
doubleword at 0x1000 on a 64-bit target, if two hardware watchpoint
registers were used to track these separately, one of them may not be
hit. Or if you have one Watchpoint on a variable with a condition set,
and another Watchpoint on that same variable with a command defined or
different condition, or ignorecount, both of those Watchpoints need to
evaluate their criteria/commands when their WatchpointResource has been
hit.
There's a bit of code movement to rearrange things in the direction I'll
need for implementing this feature, so I want to start with reviewing &
landing this mostly NFC patch and we can focus on the algorithmic
choices about how WatchpointResources are shared and handled as they're
triggeed, separately.
This patch also stops printing "Watchpoint <n> hit: old value: <x>, new
vlaue: <y>" for Read watchpoints. I could make an argument for print
"Watchpoint <n> hit: current value <x>" but the current output doesn't
make any sense, and the user can print the value if they are
particularly interested. Read watchpoints are used primarily to
understand what code is reading a variable.
This patch adds more fallbacks for how to print the objects being
watched if we have types, instead of assuming they are all integral
values, so a struct will print its elements. As large watchpoints are
added, we'll be doing a lot more of those.
To track the WatchpointSP in the WatchpointResources, I changed the
internal API which took a WatchpointSP and devolved it to a Watchpoint*,
which meant touching several different Process files. I removed the
watchpoint code in ProcessKDP which only reported that watchpoints
aren't supported, the base class does that already.
I haven't yet changed how we receive a watchpoint to identify the
WatchpointResource responsible for the trigger, and identify all
Watchpoints that are using this Resource to evaluate their conditions
etc. This is the same work that a BreakpointSite needs to do when it has
been tiggered, where multiple Breakpoints may be at the same address.
There is not yet any printing of the Resources that a Watchpoint is
implemented in terms of ("watchpoint list", or
SBWatchpoint::GetDescription).
"watchpoint set var" and "watchpoint set expression" take a size
argument which was previously 1, 2, 4, or 8 (an enum). I've changed this
to an unsigned int. Most hardware implementations can only watch 1, 2,
4, 8 byte ranges, but with Resources we'll allow a user to ask for
different sized watchpoints and set them in hardware-expressble terms
soon.
I've annotated areas where I know there is work still needed with
LWP_TODO that I'll be working on once this is landed.
I've tested this on aarch64 macOS, aarch64 Linux, and Intel macOS.
https://discourse.llvm.org/t/rfc-large-watchpoint-support-in-lldb/72116
(cherry picked from commit fc6b72523f3d73b921690a713e97a433c96066c6)
...and follow ups.
As it has caused test failures on Linux Arm and AArch64:
https://lab.llvm.org/buildbot/#/builders/96/builds/49126https://lab.llvm.org/buildbot/#/builders/17/builds/45824
```
lldb-shell :: Subprocess/clone-follow-child-wp.test
lldb-shell :: Subprocess/fork-follow-child-wp.test
lldb-shell :: Subprocess/vfork-follow-child-wp.test
```
This reverts commit a6c62bf1a4717accc852463b664cd1012237d334,
commit a0a1ff3ab40e347589b4e27d8fd350c600526735 and commit
fc6b72523f3d73b921690a713e97a433c96066c6.
This patch is rearranging code a bit to add WatchpointResources to
Process. A WatchpointResource is meant to represent a hardware
watchpoint register in the inferior process. It has an address, a size,
a type, and a list of Watchpoints that are using this
WatchpointResource.
This current patch doesn't add any of the features of
WatchpointResources that make them interesting -- a user asking to watch
a 24 byte object could watch this with three 8 byte WatchpointResources.
Or a Watchpoint on 1 byte at 0x1002 and a second watchpoint on 1 byte at
0x1003, these must both be served by a single WatchpointResource on that
doubleword at 0x1000 on a 64-bit target, if two hardware watchpoint
registers were used to track these separately, one of them may not be
hit. Or if you have one Watchpoint on a variable with a condition set,
and another Watchpoint on that same variable with a command defined or
different condition, or ignorecount, both of those Watchpoints need to
evaluate their criteria/commands when their WatchpointResource has been
hit.
There's a bit of code movement to rearrange things in the direction I'll
need for implementing this feature, so I want to start with reviewing &
landing this mostly NFC patch and we can focus on the algorithmic
choices about how WatchpointResources are shared and handled as they're
triggeed, separately.
This patch also stops printing "Watchpoint <n> hit: old value: <x>, new
vlaue: <y>" for Read watchpoints. I could make an argument for print
"Watchpoint <n> hit: current value <x>" but the current output doesn't
make any sense, and the user can print the value if they are
particularly interested. Read watchpoints are used primarily to
understand what code is reading a variable.
This patch adds more fallbacks for how to print the objects being
watched if we have types, instead of assuming they are all integral
values, so a struct will print its elements. As large watchpoints are
added, we'll be doing a lot more of those.
To track the WatchpointSP in the WatchpointResources, I changed the
internal API which took a WatchpointSP and devolved it to a Watchpoint*,
which meant touching several different Process files. I removed the
watchpoint code in ProcessKDP which only reported that watchpoints
aren't supported, the base class does that already.
I haven't yet changed how we receive a watchpoint to identify the
WatchpointResource responsible for the trigger, and identify all
Watchpoints that are using this Resource to evaluate their conditions
etc. This is the same work that a BreakpointSite needs to do when it has
been tiggered, where multiple Breakpoints may be at the same address.
There is not yet any printing of the Resources that a Watchpoint is
implemented in terms of ("watchpoint list", or
SBWatchpoint::GetDescription).
"watchpoint set var" and "watchpoint set expression" take a size
argument which was previously 1, 2, 4, or 8 (an enum). I've changed this
to an unsigned int. Most hardware implementations can only watch 1, 2,
4, 8 byte ranges, but with Resources we'll allow a user to ask for
different sized watchpoints and set them in hardware-expressble terms
soon.
I've annotated areas where I know there is work still needed with
LWP_TODO that I'll be working on once this is landed.
I've tested this on aarch64 macOS, aarch64 Linux, and Intel macOS.
https://discourse.llvm.org/t/rfc-large-watchpoint-support-in-lldb/72116
The Watchpoint and Breakpoint objects try to track the hardware index
that was used for them, if they are hardware wp/bp's. The majority of
our debugging goes over the gdb remote serial protocol, and when we set
the watchpoint/breakpoint, there is no (standard) way for the remote
stub to communicate to lldb which hardware index was used. We have an
lldb-extension packet to query the total number of watchpoint registers.
When a watchpoint is hit, there is an lldb extension to the stop reply
packet (documented in lldb-gdb-remote.txt) to describe the watchpoint
including its actual hardware index,
<addr within wp range> <wp hw index> <actual accessed address>
(the third field is specifically needed for MIPS). At this point, if the
stub reported these three fields (the stub is only required to provide
the first), we can know the actual hardware index for this watchpoint.
Breakpoints are worse; there's never any way for us to be notified about
which hardware index was used. Breakpoints got this as a side effect of
inherting from StoppointSite with Watchpoints.
We expose the watchpoint hardware index through "watchpoint list -v" and
through SBWatchpoint::GetHardwareIndex.
With my large watchpoint support, there is no *single* hardware index
that may be used for a watchpoint, it may need multiple resources. Also
I don't see what a user is supposed to do with this information, or an
IDE. Knowing the total number of watchpoint registers on the target, and
knowing how many Watchpoint Resources are currently in use, is helpful.
Knowing how many Watchpoint Resources
a single user-specified watchpoint needed to be implemented is useful.
But knowing which registers were used is an implementation detail and
not available until we hit the watchpoint when using gdb remote serial
protocol.
So given all that, I'm removing watchpoint hardware index numbers. I'm
changing the SB API to always return -1.
This reverts commit a7b78cac9a77e3ef6bbbd8ab1a559891dc693401.
With updates to the tests.
TestWatchTaggedAddress.py: Updated the expected watchpoint types,
though I'm not sure there should be a differnt default for the two
ways of setting them, that needs to be confirmed.
TestStepOverWatchpoint.py: Skipped this everywhere because I think
what used to happen is you couldn't put 2 watchpoints on the same
address (after alignment). I guess that this is now allowed because
modify watchpoints aren't accounted for, but likely should be.
Needs investigating.
This reverts commit 933ad5c897ee366759a54869b35b2d7285a92137.
This caused 1 test failure and an unexpected pass on AArch64 Linux:
https://lab.llvm.org/buildbot/#/builders/96/builds/45765
Wasn't reported because the bot was already red at the time.
Watchpoints in lldb can be either 'read', 'write', or 'read/write'. This
is exposing the actual behavior of hardware watchpoints. gdb has a
different behavior: a "write" type watchpoint only stops when the
watched memory region *changes*.
A user is using a watchpoint for one of three reasons:
1. Want to find what is changing/corrupting this memory.
2. Want to find what is writing to this memory.
3. Want to find what is reading from this memory.
I believe (1) is the most common use case for watchpoints, and it
currently can't be done in lldb -- the user needs to continue every time
the same value is written to the watched-memory manually. I think gdb's
behavior is the correct one. There are some use cases where a developer
wants to find every function that writes/reads to/from a memory region,
regardless of value, I want to still allow that functionality.
This is also a bit of groundwork for my large watchpoint support
proposal
https://discourse.llvm.org/t/rfc-large-watchpoint-support-in-lldb/72116
where I will be adding support for AArch64 MASK watchpoints which watch
power-of-2 memory regions. A user might ask to watch 24 bytes, and a
MASK watchpoint stub can do this with a 32-byte MASK watchpoint if it is
properly aligned. And we need to ignore writes to the final 8 bytes of
that watched region, and not show those hits to the user.
This patch adds a new 'modify' watchpoint type and it is the default.
Re-landing this patch after addressing testsuite failures found in CI on
Linux, Intel machines, and windows.
rdar://108234227
Watchpoints in lldb can be either 'read', 'write', or 'read/write'. This
is exposing the actual behavior of hardware watchpoints. gdb has a
different behavior: a "write" type watchpoint only stops when the
watched memory region *changes*.
A user is using a watchpoint for one of three reasons:
1. Want to find what is changing/corrupting this memory.
2. Want to find what is writing to this memory.
3. Want to find what is reading from this memory.
I believe (1) is the most common use case for watchpoints, and it
currently can't be done in lldb -- the user needs to continue every time
the same value is written to the watched-memory manually. I think gdb's
behavior is the correct one. There are some use cases where a developer
wants to find every function that writes/reads to/from a memory region,
regardless of value, I want to still allow that functionality.
This is also a bit of groundwork for my large watchpoint support
proposal
https://discourse.llvm.org/t/rfc-large-watchpoint-support-in-lldb/72116
where I will be adding support for AArch64 MASK watchpoints which watch
power-of-2 memory regions. A user might ask to watch 24 bytes, and a
MASK watchpoint stub can do this with a 32-byte MASK watchpoint if it is
properly aligned. And we need to ignore writes to the final 8 bytes of
that watched region, and not show those hits to the user.
This patch adds a new 'modify' watchpoint type and it is the default.
rdar://108234227
This is an ongoing series of commits that are reformatting our Python
code. Reformatting is done with `black` (23.1.0).
If you end up having problems merging this commit because you have made
changes to a python file, the best way to handle that is to run `git
checkout --ours <yourfile>` and then reformat it with black.
RFC: https://discourse.llvm.org/t/rfc-document-and-standardize-python-code-style
Differential revision: https://reviews.llvm.org/D151460
Add suport for MASK style watchpoints on AArch64 in debugserver
on Darwin systems, for watching power-of-2 sized memory ranges.
More work needed in lldb before this can be exposed to the user
(because they will often try watching memory ranges that are not
exactly power-of-2 in size/alignment) but this is the first part
of adding that capability.
Differential Revision: https://reviews.llvm.org/D149792
rdar://108233371
This patch adds the following methods:
* `GetType()`
* `GetWatchValueKind()`
* `GetWatchSpec()`
* `IsWatchingReads()`
* `IsWatchingWrites()`
These mostly expose methods that `lldb_private::Watchpoint` already
had. Tests are included that exercise these new methods.
The motivation for exposing these are as follows:
* `GetType()` - With this information and the address from a watchpoint
it is now possible to construct an SBValue from an SBWatchpoint.
Previously this wasn't possible. The included test case illustrates
doing this.
* `GetWatchValueKind()` - This allows the caller to determine whether the
watchpoint is a variable watchpoint or an expression watchpoint. A new
enum (`WatchpointValueKind`) has been introduced to represent the
return values. Unfortunately the name `WatchpointKind` was already
taken.
* `GetWatchSpec()` - This allows (at least for variable watchpoints)
to use a sensible name for SBValues created from an SBWatchpoint.
* `IsWatchingReads()` - This allow checking if a watchpoint is
monitoring read accesses.
* `IsWatchingWRites()` - This allow checking if a watchpoint is
monitoring write accesses.
rdar://105606978
Reviewers: jingham, mib, bulbazord, jasonmolenda, JDevlieghere
Differential Revision: https://reviews.llvm.org/D144937
Eliminate boilerplate of having each test manually assign to `mydir` by calling
`compute_mydir` in lldbtest.py.
Differential Revision: https://reviews.llvm.org/D128077
Skip all watchpoint hit-count/ignore-count tests for multithreaded
API tests for now on arm64 Darwin.
On AArch64, insns that trigger a WP are rolled back and we are
notified. lldb needs to disable the WP, insn step, re-enable it,
then report it to the user. lldb only does this full step action
for the "selected thread", and so when a program stops with
multiple threads hitting a stop reason, some of them watchpoints,
any non-selected-thread will not be completed in this way. But
all threads with the initial watchpoint exception will have their
hit-count/ignore-counts updated. When we resume execution, the
other threads sitting at the instruction will again execute &
trigger the WP exceptoin again, repeating until we've gone through
all of the threads.
This bug is being tracked in llvm.org/pr49433 and inside apple
in rdar://93863107
There is a .categories file in the python_api directory that makes all nested tests
belong to the category "pyapi". The decorator is unnecessary for these tests.
Convert `assertTrue(a == b)` to `assertEqual(a, b)` to produce better failure messages.
These were mostly done via regex search & replace, with some manual fixes.
Differential Revision: https://reviews.llvm.org/D95813
Make category-specifying files visible. There is really no good reason
to keep them hidden, and having them visible increases the chances
that someone will actually spot them.
Differential Revision: https://reviews.llvm.org/D91065
Summary:
Around a third of our test sources have LLVM license headers. This patch removes those headers from all test
sources and also fixes any tests that depended on the length of the license header.
The reasons for this are:
* A few tests verify line numbers and will start failing if the number of lines in the LLVM license header changes. Once I landed my patch for valid SourceLocations in debug info we will probably have even more tests that verify line numbers.
* No other LLVM project is putting license headers in its test files to my knowledge.
* They make the test sources much more verbose than they have to be. Several tests have longer license headers than the actual test source.
For the record, the following tests had their line numbers changed to pass with the removal of the license header:
lldb-api :: functionalities/breakpoint/breakpoint_by_line_and_column/TestBreakpointByLineAndColumn.py
lldb-shell :: Reproducer/TestGDBRemoteRepro.test
lldb-shell :: Reproducer/TestMultipleTargets.test
lldb-shell :: Reproducer/TestReuseDirectory.test
lldb-shell :: ExecControl/StopHook/stop-hook-threads.test
lldb-shell :: ExecControl/StopHook/stop-hook.test
lldb-api :: lang/objc/exceptions/TestObjCExceptions.py
Reviewers: #lldb, espindola, JDevlieghere
Reviewed By: #lldb, JDevlieghere
Subscribers: emaste, aprantl, arphaman, JDevlieghere, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D74839
Summary: Moves lldbsuite tests to lldb/test/API.
This is a largely mechanical change, moved with the following steps:
```
rm lldb/test/API/testcases
mkdir -p lldb/test/API/{test_runner/test,tools/lldb-{server,vscode}}
mv lldb/packages/Python/lldbsuite/test/test_runner/test lldb/test/API/test_runner
for d in $(find lldb/packages/Python/lldbsuite/test/* -maxdepth 0 -type d | egrep -v "make|plugins|test_runner|tools"); do mv $d lldb/test/API; done
for d in $(find lldb/packages/Python/lldbsuite/test/tools/lldb-vscode -maxdepth 1 -mindepth 1 | grep -v ".py"); do mv $d lldb/test/API/tools/lldb-vscode; done
for d in $(find lldb/packages/Python/lldbsuite/test/tools/lldb-server -maxdepth 1 -mindepth 1 | egrep -v "gdbremote_testcase.py|lldbgdbserverutils.py|socket_packet_pump.py"); do mv $d lldb/test/API/tools/lldb-server; done
```
lldb/packages/Python/lldbsuite/__init__.py and lldb/test/API/lit.cfg.py were also updated with the new directory structure.
Reviewers: labath, JDevlieghere
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D71151
