[Lldb-commits] [lldb] [lldb] Change lldb's breakpoint handling behavior (PR #96260)
Jason Molenda via lldb-commits
lldb-commits at lists.llvm.org
Thu Jun 20 17:56:06 PDT 2024
https://github.com/jasonmolenda created https://github.com/llvm/llvm-project/pull/96260
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, but I'm convinced it 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 thread plan 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. I discussed this with Jim, and trying to paper over this behavior will lead to more complicated scenarios behaving non-intuitively. And mostly it's the testsuite that was trying to instruction step past a breakpoint and getting thrown off -- and I changed those tests to expect the new behavior.
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 (whether we hit it or not), we call Thread::SetThreadStoppedAtBreakpointSite(pc) to record the state at the point when the thread stopped. (so we can detect newly-added breakpoints, or when the pc is changed to an instruction that is a BreakpointSite)
2. When we have actually hit a breakpoint, and it is enabled for this thread, we call Thread::SetThreadHitBreakpointAtAddr(pc) so we know that it should be silently stepped past when we resume execution.
When resuming, we silently step over a breakpoint if we've hit it, or if it is newly added (or the pc was changed to an existing BreakpointSite).
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.
rdar://123942164
>From 9b541e6a035635e26c6a24eca022de8552fa4c17 Mon Sep 17 00:00:00 2001
From: Jason Molenda <jmolenda at apple.com>
Date: Thu, 20 Jun 2024 17:53:17 -0700
Subject: [PATCH] [lldb] Change lldb's breakpoint handling behavior
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, but I'm convinced it 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
thread plan 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. I discussed this with Jim, and trying
to paper over this behavior will lead to more complicated scenarios
behaving non-intuitively. And mostly it's the testsuite that was
trying to instruction step past a breakpoint and getting thrown off
-- and I changed those tests to expect the new behavior.
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 (whether we hit it or not),
we call Thread::SetThreadStoppedAtBreakpointSite(pc) to record the
state at the point when the thread stopped. (so we can detect
newly-added breakpoints, or when the pc is changed to an instruction
that is a BreakpointSite)
2. When we have actually hit a breakpoint, and it is enabled for
this thread, we call Thread::SetThreadHitBreakpointAtAddr(pc) so
we know that it should be silently stepped past when we resume
execution.
When resuming, we silently step over a breakpoint if we've hit it,
or if it is newly added (or the pc was changed to an existing
BreakpointSite).
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.
rdar://123942164
---
lldb/include/lldb/Target/Thread.h | 29 ++
.../Process/Utility/StopInfoMachException.cpp | 296 +++++++-----------
.../Process/Windows/Common/ProcessWindows.cpp | 16 +-
.../Process/gdb-remote/ProcessGDBRemote.cpp | 118 +++----
.../Process/scripted/ScriptedThread.cpp | 9 +
lldb/source/Target/Thread.cpp | 17 +-
.../TestConsecutiveBreakpoints.py | 26 +-
.../TestStepOverBreakpoint.py | 6 +-
8 files changed, 235 insertions(+), 282 deletions(-)
diff --git a/lldb/include/lldb/Target/Thread.h b/lldb/include/lldb/Target/Thread.h
index c17bddf4d98b8..1e1aead896018 100644
--- a/lldb/include/lldb/Target/Thread.h
+++ b/lldb/include/lldb/Target/Thread.h
@@ -128,6 +128,11 @@ class Thread : public std::enable_shared_from_this<Thread>,
register_backup_sp; // You need to restore the registers, of course...
uint32_t current_inlined_depth;
lldb::addr_t current_inlined_pc;
+ lldb::addr_t
+ hit_bp_at_addr; // Set to the address of a breakpoint that we have hit.
+ lldb::addr_t bpsite_at_stop_pc; // Set to the address of a breakpoint
+ // instruction that we have not yet hit, but
+ // will hit when we resume.
};
/// Constructor
@@ -377,6 +382,19 @@ class Thread : public std::enable_shared_from_this<Thread>,
virtual void SetQueueLibdispatchQueueAddress(lldb::addr_t dispatch_queue_t) {}
+ /// When a thread has executed/trapped a breakpoint, set the address of that
+ /// breakpoint so we know it has been hit already, and should be silently
+ /// stepped past on resume.
+ void SetThreadHitBreakpointAtAddr(lldb::addr_t pc) { m_hit_bp_at_addr = pc; }
+
+ /// When a thread stops at a breakpoint instruction/address, but has not yet
+ /// executed/triggered it, record that so we can detect when a user adds a
+ /// breakpoint (or changes a thread to a breakpoint site) and we need to
+ /// silently step past that when resuming.
+ void SetThreadStoppedAtBreakpointSite(lldb::addr_t pc) {
+ m_bpsite_at_stop_pc = pc;
+ }
+
/// Whether this Thread already has all the Queue information cached or not
///
/// A Thread may be associated with a libdispatch work Queue at a given
@@ -1311,6 +1329,17 @@ class Thread : public std::enable_shared_from_this<Thread>,
bool m_should_run_before_public_stop; // If this thread has "stop others"
// private work to do, then it will
// set this.
+ lldb::addr_t m_hit_bp_at_addr; // If this thread originally stopped at a
+ // breakpoint instruction, AND HIT IT,
+ // record the address of that breakpoint.
+ // LLDB_INVALID_ADDRESS if this thread did
+ // not stop at a breakpoint insn, or did not
+ // hit it yet.
+ lldb::addr_t m_bpsite_at_stop_pc; // If this thread originally stopped at a
+ // breakpoint site, record the address of
+ // that breakpoint site.
+ // LLDB_INVALID_ADDRESS if this thread did
+ // not stop at a breakpoint site.
const uint32_t m_index_id; ///< A unique 1 based index assigned to each thread
/// for easy UI/command line access.
lldb::RegisterContextSP m_reg_context_sp; ///< The register context for this
diff --git a/lldb/source/Plugins/Process/Utility/StopInfoMachException.cpp b/lldb/source/Plugins/Process/Utility/StopInfoMachException.cpp
index 25cee369d7ee3..8087ef1accde8 100644
--- a/lldb/source/Plugins/Process/Utility/StopInfoMachException.cpp
+++ b/lldb/source/Plugins/Process/Utility/StopInfoMachException.cpp
@@ -488,38 +488,6 @@ const char *StopInfoMachException::GetDescription() {
return m_description.c_str();
}
-static StopInfoSP GetStopInfoForHardwareBP(Thread &thread, Target *target,
- uint32_t exc_data_count,
- uint64_t exc_sub_code,
- uint64_t exc_sub_sub_code) {
- // Try hardware watchpoint.
- if (target) {
- // The exc_sub_code indicates the data break address.
- WatchpointResourceSP wp_rsrc_sp =
- target->GetProcessSP()->GetWatchpointResourceList().FindByAddress(
- (addr_t)exc_sub_code);
- if (wp_rsrc_sp && wp_rsrc_sp->GetNumberOfConstituents() > 0) {
- return StopInfo::CreateStopReasonWithWatchpointID(
- thread, wp_rsrc_sp->GetConstituentAtIndex(0)->GetID());
- }
- }
-
- // Try hardware breakpoint.
- ProcessSP process_sp(thread.GetProcess());
- if (process_sp) {
- // The exc_sub_code indicates the data break address.
- lldb::BreakpointSiteSP bp_sp =
- process_sp->GetBreakpointSiteList().FindByAddress(
- (lldb::addr_t)exc_sub_code);
- if (bp_sp && bp_sp->IsEnabled()) {
- return StopInfo::CreateStopReasonWithBreakpointSiteID(thread,
- bp_sp->GetID());
- }
- }
-
- return nullptr;
-}
-
#if defined(__APPLE__)
const char *
StopInfoMachException::MachException::Name(exception_type_t exc_type) {
@@ -633,171 +601,143 @@ StopInfoSP StopInfoMachException::CreateStopReasonWithMachException(
}
break;
+ // [exc_type, exc_code, exc_sub_code, exc_sub_sub_code]
+ //
+ // Instruction step:
+ // [6, 1, 0]
+ // Intel KDP [6, 3, ??]
+ // armv7 [6, 0x102, <stop-pc>] Same as software breakpoint!
+ //
+ // Software breakpoint:
+ // x86 [6, 2, 0]
+ // Intel KDP [6, 2, <bp-addr + 1>]
+ // arm64 [6, 1, <bp-addr>]
+ // armv7 [6, 0x102, <bp-addr>] Same as instruction step!
+ //
+ // Hardware breakpoint:
+ // x86 [6, 1, <bp-addr>, 0]
+ // x86/Rosetta not implemented, see software breakpoint
+ // arm64 [6, 1, <bp-addr>]
+ // armv7 not implemented, see software breakpoint
+ //
+ // Hardware watchpoint:
+ // x86 [6, 1, <accessed-addr>, 0] (both Intel hw and Rosetta)
+ // arm64 [6, 0x102, <accessed-addr>, 0]
+ // armv7 [6, 0x102, <accessed-addr>, 0]
+ //
+ // arm64 BRK instruction (imm arg not reflected in the ME)
+ // [ 6, 1, <addr-of-BRK-insn>]
+ //
+ // In order of codes mach exceptions:
+ // [6, 1, 0] - instruction step
+ // [6, 1, <bp-addr>] - hardware breakpoint or watchpoint
+ //
+ // [6, 2, 0] - software breakpoint
+ // [6, 2, <bp-addr + 1>] - software breakpoint
+ //
+ // [6, 3] - instruction step
+ //
+ // [6, 0x102, <stop-pc>] armv7 instruction step
+ // [6, 0x102, <bp-addr>] armv7 software breakpoint
+ // [6, 0x102, <accessed-addr>, 0] arm64/armv7 watchpoint
case 6: // EXC_BREAKPOINT
{
- bool is_actual_breakpoint = false;
- bool is_trace_if_actual_breakpoint_missing = false;
- switch (cpu) {
- case llvm::Triple::x86:
- case llvm::Triple::x86_64:
- if (exc_code == 1) // EXC_I386_SGL
- {
- if (!exc_sub_code) {
- // This looks like a plain trap.
- // Have to check if there is a breakpoint here as well. When you
- // single-step onto a trap, the single step stops you not to trap.
- // Since we also do that check below, let's just use that logic.
- is_actual_breakpoint = true;
- is_trace_if_actual_breakpoint_missing = true;
- } else {
- if (StopInfoSP stop_info =
- GetStopInfoForHardwareBP(thread, target, exc_data_count,
- exc_sub_code, exc_sub_sub_code))
- return stop_info;
- }
- } else if (exc_code == 2 || // EXC_I386_BPT
- exc_code == 3) // EXC_I386_BPTFLT
- {
- // KDP returns EXC_I386_BPTFLT for trace breakpoints
- if (exc_code == 3)
- is_trace_if_actual_breakpoint_missing = true;
-
- is_actual_breakpoint = true;
- if (!pc_already_adjusted)
- pc_decrement = 1;
- }
- break;
+ bool stopped_by_hitting_breakpoint = false;
+ bool stopped_by_completing_stepi = false;
+ bool stopped_watchpoint = false;
+ std::optional<addr_t> value;
+
+ // exc_code 1
+ if (exc_code == 1 && exc_sub_code == 0)
+ stopped_by_completing_stepi = true;
+ if (exc_code == 1 && exc_sub_code != 0) {
+ stopped_by_hitting_breakpoint = true;
+ stopped_watchpoint = true;
+ value = exc_sub_code;
+ }
- case llvm::Triple::arm:
- case llvm::Triple::thumb:
- if (exc_code == 0x102) // EXC_ARM_DA_DEBUG
- {
- // LWP_TODO: We need to find the WatchpointResource that matches
- // the address, and evaluate its Watchpoints.
-
- // It's a watchpoint, then, if the exc_sub_code indicates a
- // known/enabled data break address from our watchpoint list.
- lldb::WatchpointSP wp_sp;
- if (target)
- wp_sp = target->GetWatchpointList().FindByAddress(
- (lldb::addr_t)exc_sub_code);
- if (wp_sp && wp_sp->IsEnabled()) {
- return StopInfo::CreateStopReasonWithWatchpointID(thread,
- wp_sp->GetID());
- } else {
- is_actual_breakpoint = true;
- is_trace_if_actual_breakpoint_missing = true;
- }
- } else if (exc_code == 1) // EXC_ARM_BREAKPOINT
- {
- is_actual_breakpoint = true;
- is_trace_if_actual_breakpoint_missing = true;
- } else if (exc_code == 0) // FIXME not EXC_ARM_BREAKPOINT but a kernel
- // is currently returning this so accept it
- // as indicating a breakpoint until the
- // kernel is fixed
- {
- is_actual_breakpoint = true;
- is_trace_if_actual_breakpoint_missing = true;
- }
- break;
+ // exc_code 2
+ if (exc_code == 2 && exc_sub_code == 0)
+ stopped_by_hitting_breakpoint = true;
+ if (exc_code == 2 && exc_sub_code != 0) {
+ stopped_by_hitting_breakpoint = true;
+ // Intel KDP software breakpoint
+ if (!pc_already_adjusted)
+ pc_decrement = 1;
+ }
- case llvm::Triple::aarch64_32:
- case llvm::Triple::aarch64: {
- // xnu describes three things with type EXC_BREAKPOINT:
- //
- // exc_code 0x102 [EXC_ARM_DA_DEBUG], exc_sub_code addr-of-insn
- // Watchpoint access. exc_sub_code is the address of the
- // instruction which trigged the watchpoint trap.
- // debugserver may add the watchpoint number that was triggered
- // in exc_sub_sub_code.
- //
- // exc_code 1 [EXC_ARM_BREAKPOINT], exc_sub_code 0
- // Instruction step has completed.
- //
- // exc_code 1 [EXC_ARM_BREAKPOINT], exc_sub_code address-of-instruction
- // Software breakpoint instruction executed.
-
- if (exc_code == 1 && exc_sub_code == 0) // EXC_ARM_BREAKPOINT
- {
- // This is hit when we single instruction step aka MDSCR_EL1 SS bit 0
- // is set
- is_actual_breakpoint = true;
- is_trace_if_actual_breakpoint_missing = true;
- if (thread.GetTemporaryResumeState() != eStateStepping)
- not_stepping_but_got_singlestep_exception = true;
- }
- if (exc_code == 0x102) // EXC_ARM_DA_DEBUG
- {
- // LWP_TODO: We need to find the WatchpointResource that matches
- // the address, and evaluate its Watchpoints.
-
- // It's a watchpoint, then, if the exc_sub_code indicates a
- // known/enabled data break address from our watchpoint list.
- lldb::WatchpointSP wp_sp;
- if (target)
- wp_sp = target->GetWatchpointList().FindByAddress(
- (lldb::addr_t)exc_sub_code);
- if (wp_sp && wp_sp->IsEnabled()) {
- return StopInfo::CreateStopReasonWithWatchpointID(thread,
- wp_sp->GetID());
- }
- // EXC_ARM_DA_DEBUG seems to be reused for EXC_BREAKPOINT as well as
- // EXC_BAD_ACCESS
- if (thread.GetTemporaryResumeState() == eStateStepping)
- return StopInfo::CreateStopReasonToTrace(thread);
+ // exc_code 3
+ if (exc_code == 3)
+ stopped_by_completing_stepi = true;
+
+ // exc_code 0x102
+ if (exc_code == 0x102 && exc_sub_code != 0) {
+ if (cpu == llvm::Triple::arm || cpu == llvm::Triple::thumb) {
+ stopped_by_hitting_breakpoint = true;
+ stopped_by_completing_stepi = true;
}
- // It looks like exc_sub_code has the 4 bytes of the instruction that
- // triggered the exception, i.e. our breakpoint opcode
- is_actual_breakpoint = exc_code == 1;
- break;
+ stopped_watchpoint = true;
+ value = exc_sub_code;
}
- default:
- break;
- }
+ // Go through the reasons why we stopped, starting
+ // with the easiest to detect unambiguously. We
+ // may have multiple possible reasons set.
- if (is_actual_breakpoint) {
+ if (stopped_by_hitting_breakpoint) {
+ ProcessSP process_sp(thread.GetProcess());
RegisterContextSP reg_ctx_sp(thread.GetRegisterContext());
- addr_t pc = reg_ctx_sp->GetPC() - pc_decrement;
-
- ProcessSP process_sp(thread.CalculateProcess());
-
- lldb::BreakpointSiteSP bp_site_sp;
- if (process_sp)
+ BreakpointSiteSP bp_site_sp;
+ addr_t pc = LLDB_INVALID_ADDRESS;
+ if (reg_ctx_sp)
+ pc = reg_ctx_sp->GetPC() - pc_decrement;
+ else if (value)
+ pc = *value;
+
+ if (value)
+ bp_site_sp = process_sp->GetBreakpointSiteList().FindByAddress(*value);
+ if (!bp_site_sp && reg_ctx_sp) {
bp_site_sp = process_sp->GetBreakpointSiteList().FindByAddress(pc);
+ }
if (bp_site_sp && bp_site_sp->IsEnabled()) {
- // Update the PC if we were asked to do so, but only do so if we find
- // a breakpoint that we know about cause this could be a trap
- // instruction in the code
- if (pc_decrement > 0 && adjust_pc_if_needed)
- reg_ctx_sp->SetPC(pc);
-
- // If the breakpoint is for this thread, then we'll report the hit,
- // but if it is for another thread, we can just report no reason. We
- // don't need to worry about stepping over the breakpoint here, that
- // will be taken care of when the thread resumes and notices that
- // there's a breakpoint under the pc. If we have an operating system
- // plug-in, we might have set a thread specific breakpoint using the
- // operating system thread ID, so we can't make any assumptions about
- // the thread ID so we must always report the breakpoint regardless
- // of the thread.
+ // If we have an operating system plug-in, we might have set a thread
+ // specific breakpoint using the operating system thread ID, so we
+ // can't make any assumptions about the thread ID so we must always
+ // report the breakpoint regardless of the thread.
if (bp_site_sp->ValidForThisThread(thread) ||
- thread.GetProcess()->GetOperatingSystem() != nullptr)
+ thread.GetProcess()->GetOperatingSystem() != nullptr) {
+ // Update the PC if we were asked to do so, but only do so if we find
+ // a breakpoint that we know about cause this could be a trap
+ // instruction in the code
+ if (pc_decrement > 0 && adjust_pc_if_needed && reg_ctx_sp)
+ reg_ctx_sp->SetPC(pc);
+ thread.SetThreadHitBreakpointAtAddr(pc);
return StopInfo::CreateStopReasonWithBreakpointSiteID(
thread, bp_site_sp->GetID());
- else if (is_trace_if_actual_breakpoint_missing)
- return StopInfo::CreateStopReasonToTrace(thread);
- else
+ } else {
+ thread.SetThreadHitBreakpointAtAddr(pc);
return StopInfoSP();
+ }
}
+ }
- // Don't call this a trace if we weren't single stepping this thread.
- if (is_trace_if_actual_breakpoint_missing &&
- thread.GetTemporaryResumeState() == eStateStepping) {
- return StopInfo::CreateStopReasonToTrace(thread);
+ if (stopped_watchpoint && value) {
+ WatchpointResourceSP wp_rsrc_sp =
+ target->GetProcessSP()->GetWatchpointResourceList().FindByAddress(
+ *value);
+ if (wp_rsrc_sp && wp_rsrc_sp->GetNumberOfConstituents() > 0) {
+ return StopInfo::CreateStopReasonWithWatchpointID(
+ thread, wp_rsrc_sp->GetConstituentAtIndex(0)->GetID());
}
}
+
+ if (stopped_by_completing_stepi) {
+ if (thread.GetTemporaryResumeState() != eStateStepping)
+ not_stepping_but_got_singlestep_exception = true;
+ else
+ return StopInfo::CreateStopReasonToTrace(thread);
+ }
+
} break;
case 7: // EXC_SYSCALL
diff --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp
index f383b3d40a4f3..c4005a1f51150 100644
--- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp
@@ -382,19 +382,8 @@ void ProcessWindows::RefreshStateAfterStop() {
RegisterContextSP register_context = stop_thread->GetRegisterContext();
const uint64_t pc = register_context->GetPC();
BreakpointSiteSP site(GetBreakpointSiteList().FindByAddress(pc));
- if (site && site->ValidForThisThread(*stop_thread)) {
- LLDB_LOG(log,
- "Single-stepped onto a breakpoint in process {0} at "
- "address {1:x} with breakpoint site {2}",
- m_session_data->m_debugger->GetProcess().GetProcessId(), pc,
- site->GetID());
- stop_info = StopInfo::CreateStopReasonWithBreakpointSiteID(*stop_thread,
- site->GetID());
- stop_thread->SetStopInfo(stop_info);
-
- return;
- }
-
+ if (site)
+ stop_thread->SetThreadStoppedAtBreakpointSite(pc);
auto *reg_ctx = static_cast<RegisterContextWindows *>(
stop_thread->GetRegisterContext().get());
uint32_t slot_id = reg_ctx->GetTriggeredHardwareBreakpointSlotId();
@@ -462,6 +451,7 @@ void ProcessWindows::RefreshStateAfterStop() {
stop_info = StopInfo::CreateStopReasonWithBreakpointSiteID(
*stop_thread, site->GetID());
register_context->SetPC(pc);
+ stop_thread->SetThreadHitBreakpointAtAddr(pc);
} else {
LLDB_LOG(log,
"Breakpoint site {0} is not valid for this thread, "
diff --git a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
index a5a731981299f..bad42d44503fd 100644
--- a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
@@ -1598,29 +1598,8 @@ bool ProcessGDBRemote::CalculateThreadStopInfo(ThreadGDBRemote *thread) {
// that have stop reasons, and if there is no entry for a thread, then it
// has no stop reason.
thread->GetRegisterContext()->InvalidateIfNeeded(true);
- if (!GetThreadStopInfoFromJSON(thread, m_jstopinfo_sp)) {
- // If a thread is stopped at a breakpoint site, set that as the stop
- // reason even if it hasn't executed the breakpoint instruction yet.
- // We will silently step over the breakpoint when we resume execution
- // and miss the fact that this thread hit the breakpoint.
- const size_t num_thread_ids = m_thread_ids.size();
- for (size_t i = 0; i < num_thread_ids; i++) {
- if (m_thread_ids[i] == thread->GetID() && m_thread_pcs.size() > i) {
- addr_t pc = m_thread_pcs[i];
- lldb::BreakpointSiteSP bp_site_sp =
- thread->GetProcess()->GetBreakpointSiteList().FindByAddress(pc);
- if (bp_site_sp) {
- if (bp_site_sp->ValidForThisThread(*thread)) {
- thread->SetStopInfo(
- StopInfo::CreateStopReasonWithBreakpointSiteID(
- *thread, bp_site_sp->GetID()));
- return true;
- }
- }
- }
- }
+ if (!GetThreadStopInfoFromJSON(thread, m_jstopinfo_sp))
thread->SetStopInfo(StopInfoSP());
- }
return true;
}
@@ -1729,6 +1708,12 @@ ThreadSP ProcessGDBRemote::SetThreadStopInfo(
if (ThreadSP memory_thread_sp = m_thread_list.GetBackingThread(thread_sp))
thread_sp = memory_thread_sp;
+ addr_t pc = thread_sp->GetRegisterContext()->GetPC();
+ BreakpointSiteSP bp_site_sp =
+ thread_sp->GetProcess()->GetBreakpointSiteList().FindByAddress(pc);
+ if (bp_site_sp)
+ thread_sp->SetThreadStoppedAtBreakpointSite(pc);
+
if (exc_type != 0) {
const size_t exc_data_size = exc_data.size();
@@ -1745,23 +1730,11 @@ ThreadSP ProcessGDBRemote::SetThreadStopInfo(
// to no reason.
if (!reason.empty() && reason != "none") {
if (reason == "trace") {
- addr_t pc = thread_sp->GetRegisterContext()->GetPC();
- lldb::BreakpointSiteSP bp_site_sp =
- thread_sp->GetProcess()->GetBreakpointSiteList().FindByAddress(
- pc);
-
- // If the current pc is a breakpoint site then the StopInfo should be
- // set to Breakpoint Otherwise, it will be set to Trace.
- if (bp_site_sp && bp_site_sp->ValidForThisThread(*thread_sp)) {
- thread_sp->SetStopInfo(
- StopInfo::CreateStopReasonWithBreakpointSiteID(
- *thread_sp, bp_site_sp->GetID()));
- } else
- thread_sp->SetStopInfo(
- StopInfo::CreateStopReasonToTrace(*thread_sp));
+ thread_sp->SetStopInfo(StopInfo::CreateStopReasonToTrace(*thread_sp));
handled = true;
} else if (reason == "breakpoint") {
addr_t pc = thread_sp->GetRegisterContext()->GetPC();
+ thread_sp->SetThreadHitBreakpointAtAddr(pc);
lldb::BreakpointSiteSP bp_site_sp =
thread_sp->GetProcess()->GetBreakpointSiteList().FindByAddress(
pc);
@@ -1776,6 +1749,7 @@ ThreadSP ProcessGDBRemote::SetThreadStopInfo(
thread_sp->SetStopInfo(
StopInfo::CreateStopReasonWithBreakpointSiteID(
*thread_sp, bp_site_sp->GetID()));
+ thread_sp->SetThreadHitBreakpointAtAddr(pc);
} else {
StopInfoSP invalid_stop_info_sp;
thread_sp->SetStopInfo(invalid_stop_info_sp);
@@ -1880,60 +1854,40 @@ ThreadSP ProcessGDBRemote::SetThreadStopInfo(
StopInfo::CreateStopReasonVForkDone(*thread_sp));
handled = true;
}
- } else if (!signo) {
- addr_t pc = thread_sp->GetRegisterContext()->GetPC();
- lldb::BreakpointSiteSP bp_site_sp =
- thread_sp->GetProcess()->GetBreakpointSiteList().FindByAddress(pc);
-
- // If a thread is stopped at a breakpoint site, set that as the stop
- // reason even if it hasn't executed the breakpoint instruction yet.
- // We will silently step over the breakpoint when we resume execution
- // and miss the fact that this thread hit the breakpoint.
- if (bp_site_sp && bp_site_sp->ValidForThisThread(*thread_sp)) {
- thread_sp->SetStopInfo(StopInfo::CreateStopReasonWithBreakpointSiteID(
- *thread_sp, bp_site_sp->GetID()));
- handled = true;
- }
}
if (!handled && signo && !did_exec) {
if (signo == SIGTRAP) {
// Currently we are going to assume SIGTRAP means we are either
// hitting a breakpoint or hardware single stepping.
- handled = true;
- addr_t pc =
- thread_sp->GetRegisterContext()->GetPC() + m_breakpoint_pc_offset;
- lldb::BreakpointSiteSP bp_site_sp =
- thread_sp->GetProcess()->GetBreakpointSiteList().FindByAddress(
- pc);
- if (bp_site_sp) {
- // If the breakpoint is for this thread, then we'll report the hit,
- // but if it is for another thread, we can just report no reason.
- // We don't need to worry about stepping over the breakpoint here,
- // that will be taken care of when the thread resumes and notices
- // that there's a breakpoint under the pc.
- if (bp_site_sp->ValidForThisThread(*thread_sp)) {
- if (m_breakpoint_pc_offset != 0)
- thread_sp->GetRegisterContext()->SetPC(pc);
- thread_sp->SetStopInfo(
- StopInfo::CreateStopReasonWithBreakpointSiteID(
- *thread_sp, bp_site_sp->GetID()));
- } else {
- StopInfoSP invalid_stop_info_sp;
- thread_sp->SetStopInfo(invalid_stop_info_sp);
- }
+ // If we were stepping then assume the stop was the result of the
+ // trace.
+ if (thread_sp->GetTemporaryResumeState() == eStateStepping) {
+ thread_sp->SetStopInfo(
+ StopInfo::CreateStopReasonToTrace(*thread_sp));
+ handled = true;
} else {
- // If we were stepping then assume the stop was the result of the
- // trace. If we were not stepping then report the SIGTRAP.
- // FIXME: We are still missing the case where we single step over a
- // trap instruction.
- if (thread_sp->GetTemporaryResumeState() == eStateStepping)
- thread_sp->SetStopInfo(
- StopInfo::CreateStopReasonToTrace(*thread_sp));
- else
- thread_sp->SetStopInfo(StopInfo::CreateStopReasonWithSignal(
- *thread_sp, signo, description.c_str()));
+ addr_t pc = thread_sp->GetRegisterContext()->GetPC() +
+ m_breakpoint_pc_offset;
+ lldb::BreakpointSiteSP bp_site_sp =
+ thread_sp->GetProcess()->GetBreakpointSiteList().FindByAddress(
+ pc);
+
+ if (bp_site_sp) {
+ // If the breakpoint is for this thread, then we'll report the
+ // hit, but if it is for another thread, we can just report no
+ // reason.
+ if (bp_site_sp->ValidForThisThread(*thread_sp)) {
+ if (m_breakpoint_pc_offset != 0)
+ thread_sp->GetRegisterContext()->SetPC(pc);
+ thread_sp->SetStopInfo(
+ StopInfo::CreateStopReasonWithBreakpointSiteID(
+ *thread_sp, bp_site_sp->GetID()));
+ thread_sp->SetThreadHitBreakpointAtAddr(pc);
+ handled = true;
+ }
+ }
}
}
if (!handled)
diff --git a/lldb/source/Plugins/Process/scripted/ScriptedThread.cpp b/lldb/source/Plugins/Process/scripted/ScriptedThread.cpp
index 88a4ca3b0389f..8e60e5ed827f6 100644
--- a/lldb/source/Plugins/Process/scripted/ScriptedThread.cpp
+++ b/lldb/source/Plugins/Process/scripted/ScriptedThread.cpp
@@ -254,6 +254,8 @@ bool ScriptedThread::CalculateStopInfo() {
LLDB_INVALID_BREAK_ID);
stop_info_sp =
StopInfo::CreateStopReasonWithBreakpointSiteID(*this, break_id);
+ if (RegisterContextSP reg_ctx_sp = GetRegisterContext())
+ SetThreadHitBreakpointAtAddr(reg_ctx_sp->GetPC());
} break;
case lldb::eStopReasonSignal: {
uint32_t signal;
@@ -319,6 +321,13 @@ bool ScriptedThread::CalculateStopInfo() {
.str(),
error, LLDBLog::Thread);
}
+ if (RegisterContextSP reg_ctx_sp = GetRegisterContext()) {
+ addr_t pc = reg_ctx_sp->GetPC();
+ if (BreakpointSiteSP bp_site_sp =
+ GetProcess()->GetBreakpointSiteList().FindByAddress(pc)) {
+ SetThreadStoppedAtBreakpointSite(pc);
+ }
+ }
if (!stop_info_sp)
return false;
diff --git a/lldb/source/Target/Thread.cpp b/lldb/source/Target/Thread.cpp
index e75f5a356cec2..4f9d958648e27 100644
--- a/lldb/source/Target/Thread.cpp
+++ b/lldb/source/Target/Thread.cpp
@@ -217,6 +217,8 @@ Thread::Thread(Process &process, lldb::tid_t tid, bool use_invalid_index_id)
m_process_wp(process.shared_from_this()), m_stop_info_sp(),
m_stop_info_stop_id(0), m_stop_info_override_stop_id(0),
m_should_run_before_public_stop(false),
+ m_hit_bp_at_addr(LLDB_INVALID_ADDRESS),
+ m_bpsite_at_stop_pc(LLDB_INVALID_ADDRESS),
m_index_id(use_invalid_index_id ? LLDB_INVALID_INDEX32
: process.GetNextThreadIndexID(tid)),
m_reg_context_sp(), m_state(eStateUnloaded), m_state_mutex(),
@@ -519,6 +521,8 @@ bool Thread::CheckpointThreadState(ThreadStateCheckpoint &saved_state) {
saved_state.current_inlined_depth = GetCurrentInlinedDepth();
saved_state.m_completed_plan_checkpoint =
GetPlans().CheckpointCompletedPlans();
+ saved_state.hit_bp_at_addr = m_hit_bp_at_addr;
+ saved_state.bpsite_at_stop_pc = m_bpsite_at_stop_pc;
return true;
}
@@ -554,6 +558,8 @@ void Thread::RestoreThreadStateFromCheckpoint(
saved_state.current_inlined_depth);
GetPlans().RestoreCompletedPlanCheckpoint(
saved_state.m_completed_plan_checkpoint);
+ m_hit_bp_at_addr = saved_state.hit_bp_at_addr;
+ m_bpsite_at_stop_pc = saved_state.bpsite_at_stop_pc;
}
StateType Thread::GetState() const {
@@ -622,7 +628,12 @@ void Thread::SetupForResume() {
const addr_t thread_pc = reg_ctx_sp->GetPC();
BreakpointSiteSP bp_site_sp =
GetProcess()->GetBreakpointSiteList().FindByAddress(thread_pc);
- if (bp_site_sp) {
+ // Only step over a breakpoint if the thread stopped by hitting the
+ // BreakpointSite at this pc value, or if we're at a breakpoint site
+ // that was added at this pc while stopped/we jumped to a breakpoint
+ // site.
+ if (bp_site_sp &&
+ (thread_pc == m_hit_bp_at_addr || thread_pc != m_bpsite_at_stop_pc)) {
// Note, don't assume there's a ThreadPlanStepOverBreakpoint, the
// target may not require anything special to step over a breakpoint.
@@ -711,6 +722,8 @@ bool Thread::ShouldResume(StateType resume_state) {
if (need_to_resume) {
ClearStackFrames();
+ m_hit_bp_at_addr = LLDB_INVALID_ADDRESS;
+ m_bpsite_at_stop_pc = LLDB_INVALID_ADDRESS;
// Let Thread subclasses do any special work they need to prior to resuming
WillResume(resume_state);
}
@@ -1894,6 +1907,8 @@ Unwind &Thread::GetUnwinder() {
void Thread::Flush() {
ClearStackFrames();
m_reg_context_sp.reset();
+ m_hit_bp_at_addr = LLDB_INVALID_ADDRESS;
+ m_bpsite_at_stop_pc = LLDB_INVALID_ADDRESS;
}
bool Thread::IsStillAtLastBreakpointHit() {
diff --git a/lldb/test/API/functionalities/breakpoint/consecutive_breakpoints/TestConsecutiveBreakpoints.py b/lldb/test/API/functionalities/breakpoint/consecutive_breakpoints/TestConsecutiveBreakpoints.py
index 73de4a294388b..ecea28c6e1f6d 100644
--- a/lldb/test/API/functionalities/breakpoint/consecutive_breakpoints/TestConsecutiveBreakpoints.py
+++ b/lldb/test/API/functionalities/breakpoint/consecutive_breakpoints/TestConsecutiveBreakpoints.py
@@ -2,7 +2,6 @@
Test that we handle breakpoints on consecutive instructions correctly.
"""
-
import lldb
from lldbsuite.test.decorators import *
from lldbsuite.test.lldbtest import *
@@ -64,20 +63,30 @@ def test_single_step(self):
"""Test that single step stops at the second breakpoint."""
self.prepare_test()
+ # Instruction step to the next instruction
+ # We haven't executed breakpoint2 yet, we're sitting at it now.
+ step_over = False
+ self.thread.StepInstruction(step_over)
+
step_over = False
self.thread.StepInstruction(step_over)
+ # We've now hit the breakpoint and this StepInstruction has
+ # been interrupted, it is still sitting on the thread plan stack.
+
self.assertState(self.process.GetState(), lldb.eStateStopped)
self.assertEqual(
self.thread.GetFrameAtIndex(0).GetPCAddress().GetLoadAddress(self.target),
self.bkpt_address.GetLoadAddress(self.target),
)
- self.thread = lldbutil.get_one_thread_stopped_at_breakpoint(
- self.process, self.breakpoint2
- )
- self.assertIsNotNone(
- self.thread, "Expected one thread to be stopped at breakpoint 2"
- )
+
+ # One more instruction to complete the Step that was interrupted
+ # earlier.
+ self.thread.StepInstruction(step_over)
+ strm = lldb.SBStream()
+ self.thread.GetDescription(strm)
+ self.assertIn("instruction step into", strm.GetData())
+ self.assertIsNotNone(self.thread, "Expected to see that step-in had completed")
self.finish_test()
@@ -106,4 +115,7 @@ def test_single_step_thread_specific(self):
"Stop reason should be 'plan complete'",
)
+ # Hit our second breakpoint
+ self.process.Continue()
+
self.finish_test()
diff --git a/lldb/test/API/functionalities/breakpoint/step_over_breakpoint/TestStepOverBreakpoint.py b/lldb/test/API/functionalities/breakpoint/step_over_breakpoint/TestStepOverBreakpoint.py
index 3a7440a31677a..1315288b35c55 100644
--- a/lldb/test/API/functionalities/breakpoint/step_over_breakpoint/TestStepOverBreakpoint.py
+++ b/lldb/test/API/functionalities/breakpoint/step_over_breakpoint/TestStepOverBreakpoint.py
@@ -5,7 +5,6 @@
and eStopReasonPlanComplete when breakpoint's condition fails.
"""
-
import lldb
from lldbsuite.test.decorators import *
from lldbsuite.test.lldbtest import *
@@ -90,6 +89,11 @@ def test_step_instruction(self):
self.assertGreaterEqual(step_count, steps_expected)
break
+ # We did a `stepi` when we hit our last breakpoint, and the stepi was not
+ # completed yet, so when we resume it will complete (running process.Continue()
+ # would have the same result - we step one instruction and stop again when
+ # our interrupted stepi completes).
+ self.thread.StepInstruction(True)
# Run the process until termination
self.process.Continue()
self.assertState(self.process.GetState(), lldb.eStateExited)
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