mib created this revision.
mib added reviewers: jingham, JDevlieghere, bulbazord, aprantl.
mib added a project: LLDB.
Herald added a project: All.
mib requested review of this revision.
Herald added a subscriber: lldb-commits.
If we use a variable watchpoint with a condition using a scope variable,
if we go out-of-scope, the watpoint remains active which can the
expression evaluator to fail to parse the watchpoint condition (because
of the missing varible bindings).
This was discovered after `watchpoint_callback.test` started failing on
the green dragon bot.
This patch should address that issue by setting an internal breakpoint
on the return addresss of the current frame when creating a variable
watchpoint. The breakpoint has a callback that will disable the watchpoint
if the the breakpoint execution context matches the watchpoint execution
context.
This is only enabled for local variables.
This patch also re-enables the failing test following e1086384e584
<https://reviews.llvm.org/rGe1086384e5841e861cd19d5d980394cfcf94ef98>.
rdar://109574319
Signed-off-by: Med Ismail Bennani <ism...@bennani.ma>
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D151366
Files:
lldb/include/lldb/Breakpoint/Watchpoint.h
lldb/source/Breakpoint/Watchpoint.cpp
lldb/source/Commands/CommandObjectWatchpoint.cpp
lldb/test/Shell/ScriptInterpreter/Lua/watchpoint_callback.test
lldb/test/Shell/Watchpoint/Inputs/val.c
lldb/test/Shell/Watchpoint/Inputs/watchpoint.in
lldb/test/Shell/Watchpoint/LocalVariableWatchpointDisabler.test
Index: lldb/test/Shell/Watchpoint/LocalVariableWatchpointDisabler.test
===================================================================
--- /dev/null
+++ lldb/test/Shell/Watchpoint/LocalVariableWatchpointDisabler.test
@@ -0,0 +1,3 @@
+# XFAIL: system-netbsd
+# RUN: %clang_host -x c %S/Inputs/val.c -g -o %t
+# RUN: %lldb -b -s %S/Inputs/watchpoint.in %t 2>&1 | FileCheck %S/Inputs/watchpoint.in
Index: lldb/test/Shell/Watchpoint/Inputs/watchpoint.in
===================================================================
--- /dev/null
+++ lldb/test/Shell/Watchpoint/Inputs/watchpoint.in
@@ -0,0 +1,10 @@
+breakpoint set -p "Break here"
+r
+watchpoint set variable val
+c
+# CHECK: Watchpoint 1 hit:
+# CHECK-NEXT: old value: 0
+# CHECK-NEXT: new value: 10
+# CHECK-NEXT: stop reason = watchpoint 1
+c
+# CHECK: exited with status = 0 (0x00000000)
Index: lldb/test/Shell/Watchpoint/Inputs/val.c
===================================================================
--- /dev/null
+++ lldb/test/Shell/Watchpoint/Inputs/val.c
@@ -0,0 +1,7 @@
+int main() {
+ int val = 0;
+ // Break here
+ val++;
+ val++;
+ return 0;
+}
Index: lldb/test/Shell/ScriptInterpreter/Lua/watchpoint_callback.test
===================================================================
--- lldb/test/Shell/ScriptInterpreter/Lua/watchpoint_callback.test
+++ lldb/test/Shell/ScriptInterpreter/Lua/watchpoint_callback.test
@@ -1,4 +1,4 @@
-# XFAIL: system-netbsd, system-darwin
+# XFAIL: system-netbsd
# RUN: %clang_host -x c %S/Inputs/val.c -g -o %t
# RUN: %lldb -b -s %S/Inputs/watchpoint1.in --script-language lua %t 2>&1 | FileCheck %S/Inputs/watchpoint1.in
# RUN: %lldb -b -s %S/Inputs/watchpoint2.in --script-language lua %t 2>&1 | FileCheck %S/Inputs/watchpoint2.in
Index: lldb/source/Commands/CommandObjectWatchpoint.cpp
===================================================================
--- lldb/source/Commands/CommandObjectWatchpoint.cpp
+++ lldb/source/Commands/CommandObjectWatchpoint.cpp
@@ -9,6 +9,7 @@
#include "CommandObjectWatchpoint.h"
#include "CommandObjectWatchpointCommand.h"
+#include <memory>
#include <vector>
#include "llvm/ADT/StringRef.h"
@@ -20,6 +21,7 @@
#include "lldb/Interpreter/CommandInterpreter.h"
#include "lldb/Interpreter/CommandOptionArgumentTable.h"
#include "lldb/Interpreter/CommandReturnObject.h"
+#include "lldb/Symbol/Function.h"
#include "lldb/Symbol/Variable.h"
#include "lldb/Symbol/VariableList.h"
#include "lldb/Target/StackFrame.h"
@@ -953,11 +955,15 @@
if (watch_sp) {
watch_sp->SetWatchSpec(command.GetArgumentAtIndex(0));
watch_sp->SetWatchVariable(true);
- if (var_sp && var_sp->GetDeclaration().GetFile()) {
- StreamString ss;
- // True to show fullpath for declaration file.
- var_sp->GetDeclaration().DumpStopContext(&ss, true);
- watch_sp->SetDeclInfo(std::string(ss.GetString()));
+ if (var_sp) {
+ if (var_sp->GetDeclaration().GetFile()) {
+ StreamString ss;
+ // True to show fullpath for declaration file.
+ var_sp->GetDeclaration().DumpStopContext(&ss, true);
+ watch_sp->SetDeclInfo(std::string(ss.GetString()));
+ }
+ if (var_sp->GetScope() == eValueTypeVariableLocal)
+ watch_sp->SetupVariableWatchpointDisabler(m_exe_ctx.GetFrameSP());
}
output_stream.Printf("Watchpoint created: ");
watch_sp->GetDescription(&output_stream, lldb::eDescriptionLevelFull);
Index: lldb/source/Breakpoint/Watchpoint.cpp
===================================================================
--- lldb/source/Breakpoint/Watchpoint.cpp
+++ lldb/source/Breakpoint/Watchpoint.cpp
@@ -83,6 +83,94 @@
SendWatchpointChangedEvent(eWatchpointEventTypeCommandChanged);
}
+bool Watchpoint::SetupVariableWatchpointDisabler(StackFrameSP frame_sp) const {
+ ThreadSP thread_sp = frame_sp->GetThread();
+ if (!thread_sp)
+ return false;
+
+ uint32_t return_frame_index =
+ thread_sp->GetSelectedFrameIndex(DoNoSelectMostRelevantFrame) + 1;
+ if (return_frame_index >= LLDB_INVALID_FRAME_ID)
+ return false;
+
+ StackFrameSP return_frame_sp(
+ thread_sp->GetStackFrameAtIndex(return_frame_index));
+ if (!return_frame_sp)
+ return false;
+
+ ExecutionContext exe_ctx(return_frame_sp);
+ TargetSP target_sp = exe_ctx.GetTargetSP();
+ if (!target_sp)
+ return false;
+
+ Address return_address(return_frame_sp->GetFrameCodeAddress());
+ lldb::addr_t return_addr = return_address.GetLoadAddress(target_sp.get());
+ if (return_addr == LLDB_INVALID_ADDRESS)
+ return false;
+
+ BreakpointSP bp_sp = target_sp->CreateBreakpoint(
+ return_addr, /*internal=*/true, /*request_hardware=*/false);
+ if (!bp_sp || !bp_sp->HasResolvedLocations())
+ return false;
+
+ auto wvc_up = std::make_unique<WatchpointVariableContext>(GetID(), exe_ctx);
+ auto baton_sp = std::make_shared<WatchpointVariableBaton>(std::move(wvc_up));
+ bp_sp->SetCallback(VariableWatchpointDisabler, baton_sp);
+ bp_sp->SetOneShot(true);
+ bp_sp->SetBreakpointKind("variable watchpoint disabler");
+ return true;
+}
+
+bool Watchpoint::VariableWatchpointDisabler(void *baton,
+ StoppointCallbackContext *context,
+ user_id_t break_id,
+ user_id_t break_loc_id) {
+ assert(baton && "null baton");
+ if (!baton)
+ return false;
+
+ if (!context)
+ return false;
+
+ Log *log = GetLog(LLDBLog::Watchpoints);
+
+ WatchpointVariableContext *wvc =
+ static_cast<WatchpointVariableContext *>(baton);
+
+ LLDB_LOGF(log, "Watchpoint::%s called by breakpoint %" PRIu64 ".%" PRIu64,
+ __FUNCTION__, break_id, break_loc_id);
+
+ if (wvc->watch_id == LLDB_INVALID_WATCH_ID)
+ return false;
+
+ TargetSP target_sp = context->exe_ctx_ref.GetTargetSP();
+ if (!target_sp)
+ return false;
+
+ ProcessSP process_sp = target_sp->GetProcessSP();
+ if (!process_sp)
+ return true;
+
+ WatchpointSP watch_sp =
+ target_sp->GetWatchpointList().FindByID(wvc->watch_id);
+ if (!watch_sp)
+ return false;
+
+ if (wvc->exe_ctx == context->exe_ctx_ref) {
+ LLDB_LOGF(log,
+ "Watchpoint::%s callback for watchpoint %" PRId32
+ " matched internal breakpoint execution context",
+ __FUNCTION__, watch_sp->GetID());
+ process_sp->DisableWatchpoint(watch_sp.get());
+ return false;
+ }
+ LLDB_LOGF(log,
+ "Watchpoint::%s callback for watchpoint %" PRId32
+ " didn't match internal breakpoint execution context",
+ __FUNCTION__, watch_sp->GetID());
+ return false;
+}
+
void Watchpoint::ClearCallback() {
m_options.ClearCallback();
SendWatchpointChangedEvent(eWatchpointEventTypeCommandChanged);
Index: lldb/include/lldb/Breakpoint/Watchpoint.h
===================================================================
--- lldb/include/lldb/Breakpoint/Watchpoint.h
+++ lldb/include/lldb/Breakpoint/Watchpoint.h
@@ -90,6 +90,28 @@
void SetWatchVariable(bool val);
bool CaptureWatchedValue(const ExecutionContext &exe_ctx);
+ struct WatchpointVariableContext {
+ WatchpointVariableContext(lldb::watch_id_t watch_id,
+ ExecutionContext exe_ctx)
+ : watch_id(watch_id), exe_ctx(exe_ctx) {}
+ lldb::watch_id_t watch_id;
+ ExecutionContext exe_ctx;
+ };
+
+ class WatchpointVariableBaton : public TypedBaton<WatchpointVariableContext> {
+ public:
+ WatchpointVariableBaton(std::unique_ptr<WatchpointVariableContext> Data)
+ : TypedBaton(std::move(Data)) {}
+ };
+
+ bool SetupVariableWatchpointDisabler(lldb::StackFrameSP frame_sp) const;
+
+ /// Callback routine which disable the watchpoint set on a variable when it
+ /// goes out of scope.
+ static bool VariableWatchpointDisabler(
+ void *baton, lldb_private::StoppointCallbackContext *context,
+ lldb::user_id_t break_id, lldb::user_id_t break_loc_id);
+
void GetDescription(Stream *s, lldb::DescriptionLevel level);
void Dump(Stream *s) const override;
void DumpSnapshots(Stream *s, const char *prefix = nullptr) const;
_______________________________________________
lldb-commits mailing list
lldb-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
