When quitting LLDB on Windows while a process was still running, LLDB would take unusually long to exit. This was due to a temporary deadlock: The main thread was destroying the processes. In doing so, it iterated over the target list: https://github.com/llvm/llvm-project/blob/88c64f76ed2ca226da99b99f60d316b1519fc7d8/lldb/source/Core/Debugger.cpp#L1095-L1098 This locks the list for the whole iteration. Finalizing the process would eventually lead to `DebuggerThread::StopDebugging`, which terminates the process and waits for it to exit: https://github.com/llvm/llvm-project/blob/88c64f76ed2ca226da99b99f60d316b1519fc7d8/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp#L196 The debugger loop (on a separate thread) would see that the process exited and call [`ProcessWindows::OnExitProcess`](https://github.com/llvm/llvm-project/blob/88c64f76ed2ca226da99b99f60d316b1519fc7d8/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp#L656-L673). This calls the static function [`Process::SetProcessExitStatus`](https://github.com/llvm/llvm-project/blob/0a7a7d56fc882653335beba0d1f8ea9f26089c22/lldb/source/Target/Process.cpp#L1098-L1126). This tries to find the process by its ID from the debugger's target list. Doing so requires locking the list, so the debugger thread would then be stuck on https://github.com/llvm/llvm-project/blob/0a7a7d56fc882653335beba0d1f8ea9f26089c22/lldb/source/Target/TargetList.cpp#L403 After 5s, the main thread would give up waiting. So every exit where the process was still running would be delayed by about 5s. Since `ProcessWindows` would find itself when calling `SetProcessExitStatus`, we can call `SetExitStatus` directly. This can also make some tests run faster. For example, the DIA PDB tests previously took 15s to run on my PC (24 jobs) and now take 5s. For all shell tests, the difference isn't that big (only about 3s), because most don't run into this and the tests run in parallel.
A few files of lldb dir & few other files had duplicate headers included. This patch removes those redundancies. --------- Co-authored-by: Akash Agrawal <akashag@qti.qualcomm.com>
Errors will get "error:" prefixes automatically so this is not needed.
The new test added in https://github.com/llvm/llvm-project/pull/132783 was failing on Windows because it created a new error to say it did not support the feature, but then returned the existing, default constructed error. Which was a success value. This also changes the GDBRemote error message to the same phrasing used in all the other places so we don't have to special case any platform.
This reverts commit https://github.com/llvm/llvm-project/commit/87b7f63a117c340a6d9ca47959335fd7ef6c7ad2, reapplying https://github.com/llvm/llvm-project/commit/7e66cf74fb4e6a103f923e34700a7b6f20ac2a9b with a small (and probably temporary) change to generate more debug info to help with diagnosing buildbot issues.
lldb today has two rules: When a thread stops at a BreakpointSite, we set the thread's StopReason to be "breakpoint hit" (regardless if we've actually hit the breakpoint, or if we've merely stopped *at* the breakpoint instruction/point and haven't tripped it yet). And second, when resuming a process, any thread sitting at a BreakpointSite is silently stepped over the BreakpointSite -- because we've already flagged the breakpoint hit when we stopped there originally. In this patch, I change lldb to only set a thread's stop reason to breakpoint-hit when we've actually executed the instruction/triggered the breakpoint. When we resume, we only silently step past a BreakpointSite that we've registered as hit. We preserve this state across inferior function calls that the user may do while stopped, etc. Also, when a user adds a new breakpoint at $pc while stopped, or changes $pc to be the address of a BreakpointSite, we will silently step past that breakpoint when the process resumes. This is purely a UX call, I don't think there's any person who wants to set a breakpoint at $pc and then hit it immediately on resuming. One non-intuitive UX from this change, butt is necessary: If you're stopped at a BreakpointSite that has not yet executed, you `stepi`, you will hit the breakpoint and the pc will not yet advance. This thread has not completed its stepi, and the ThreadPlanStepInstruction is still on the stack. If you then `continue` the thread, lldb will now stop and say, "instruction step completed", one instruction past the BreakpointSite. You can continue a second time to resume execution. The bugs driving this change are all from lldb dropping the real stop reason for a thread and setting it to breakpoint-hit when that was not the case. Jim hit one where we have an aarch64 watchpoint that triggers one instruction before a BreakpointSite. On this arch we are notified of the watchpoint hit after the instruction has been unrolled -- we disable the watchpoint, instruction step, re-enable the watchpoint and collect the new value. But now we're on a BreakpointSite so the watchpoint-hit stop reason is lost. Another was reported by ZequanWu in https://discourse.llvm.org/t/lldb-unable-to-break-at-start/78282 we attach to/launch a process with the pc at a BreakpointSite and misbehave. Caroline Tice mentioned it is also a problem they've had with putting a breakpoint on _dl_debug_state. The change to each Process plugin that does execution control is that 1. If we've stopped at a BreakpointSite that has not been executed yet, we will call Thread::SetThreadStoppedAtUnexecutedBP(pc) to record that. When the thread resumes, if the pc is still at the same site, we will continue, hit the breakpoint, and stop again. 2. When we've actually hit a breakpoint (enabled for this thread or not), the Process plugin should call Thread::SetThreadHitBreakpointSite(). When we go to resume the thread, we will push a step-over-breakpoint ThreadPlan before resuming. The biggest set of changes is to StopInfoMachException where we translate a Mach Exception into a stop reason. The Mach exception codes differ in a few places depending on the target (unambiguously), and I didn't want to duplicate the new code for each target so I've tested what mach exceptions we get for each action on each target, and reorganized StopInfoMachException::CreateStopReasonWithMachException to document these possible values, and handle them without specializing based on the target arch. I first landed this patch in July 2024 via https://github.com/llvm/llvm-project/pull/96260 but the CI bots and wider testing found a number of test case failures that needed to be updated, I reverted it. I've fixed all of those issues in separate PRs and this change should run cleanly on all the CI bots now. rdar://123942164
This reverts commit 7e66cf74fb4e6a103f923e34700a7b6f20ac2a9b. Breaking green dragon: https://green.lab.llvm.org/job/llvm.org/view/LLDB/job/as-lldb-cmake/19569/testReport/junit/lldb-api/functionalities_reverse-execution/TestReverseContinueWatchpoints_py/
This reverts commit a774de807e56c1147d4630bfec3110c11d41776e. This is the same changes as last time, plus: * We load the binary into the target object so that on Windows, we can resolve the locations of the functions. * We now assert that each required breakpoint has at least 1 location, to prevent an issue like that in the future. * We are less strict about the unsupported error message, because it prints "error: windows" on Windows instead of "error: gdb-remote".
Reverts llvm/llvm-project#123945 Has failed on the Windows on Arm buildbot: https://lab.llvm.org/buildbot/#/builders/141/builds/5865 ``` ******************** Unresolved Tests (2): lldb-api :: functionalities/reverse-execution/TestReverseContinueBreakpoints.py lldb-api :: functionalities/reverse-execution/TestReverseContinueWatchpoints.py ******************** Failed Tests (1): lldb-api :: functionalities/reverse-execution/TestReverseContinueNotSupported.py ``` Reverting while I reproduce locally.
This reverts commit 22561cfb443267905d4190f0e2a738e6b412457f and fixes b7b9ccf44988edf49886743ae5c3cf4184db211f (#112079). The problem is that x86_64 and Arm 32-bit have memory regions above the stack that are readable but not writeable. First Arm: ``` (lldb) memory region --all <...> [0x00000000fffcf000-0x00000000ffff0000) rw- [stack] [0x00000000ffff0000-0x00000000ffff1000) r-x [vectors] [0x00000000ffff1000-0xffffffffffffffff) --- ``` Then x86_64: ``` $ cat /proc/self/maps <...> 7ffdcd148000-7ffdcd16a000 rw-p 00000000 00:00 0 [stack] 7ffdcd193000-7ffdcd196000 r--p 00000000 00:00 0 [vvar] 7ffdcd196000-7ffdcd197000 r-xp 00000000 00:00 0 [vdso] ffffffffff600000-ffffffffff601000 --xp 00000000 00:00 0 [vsyscall] ``` Compare this to AArch64 where the test did pass: ``` $ cat /proc/self/maps <...> ffffb87dc000-ffffb87dd000 r--p 00000000 00:00 0 [vvar] ffffb87dd000-ffffb87de000 r-xp 00000000 00:00 0 [vdso] ffffb87de000-ffffb87e0000 r--p 0002a000 00:3c 76927217 /usr/lib/aarch64-linux-gnu/ld-linux-aarch64.so.1 ffffb87e0000-ffffb87e2000 rw-p 0002c000 00:3c 76927217 /usr/lib/aarch64-linux-gnu/ld-linux-aarch64.so.1 fffff4216000-fffff4237000 rw-p 00000000 00:00 0 [stack] ``` To solve this, look up the memory region of the stack pointer (using https://lldb.llvm.org/resources/lldbgdbremote.html#qmemoryregioninfo-addr) and constrain the read to within that region. Since we know the stack is all readable and writeable. I have also added skipIfRemote to the tests, since getting them working in that context is too complex to be worth it. Memory write failures now display the range they tried to write, and register write errors will show the name of the register where possible. The patch also includes a workaround for a an issue where the test code could mistake an `x` response that happens to begin with an `O` for an output packet (stdout). This workaround will not be necessary one we start using the [new implementation](https://discourse.llvm.org/t/rfc-fixing-incompatibilties-of-the-x-packet-w-r-t-gdb/84288) of the `x` packet. --------- Co-authored-by: Pavel Labath <pavel@labath.sk>