[lldb-dap] Protect SetBreakpoint with the API mutex (llvm#134030) (backport)

Protect the various SetBreakpoint functions with the API mutex. This
fixes a race condition between the breakpoint being created and the DAP
label getting added. This was causing `TestDAP_breakpointEvents.py` to
be flaky.

Fixes llvm#131242.

Author: JDevlieghere

lldb/tools/lldb-dap/Breakpoint.cpp

@@ -7,14 +7,17 @@
 //===----------------------------------------------------------------------===//
 
 #include "Breakpoint.h"
+#include "DAP.h"
 #include "JSONUtils.h"
 #include "lldb/API/SBAddress.h"
 #include "lldb/API/SBBreakpointLocation.h"
 #include "lldb/API/SBLineEntry.h"
+#include "lldb/API/SBMutex.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Support/JSON.h"
 #include <cstddef>
 #include <cstdint>
+#include <mutex>
 #include <string>
 
 using namespace lldb_dap;
@@ -72,6 +75,9 @@ void Breakpoint::CreateJsonObject(llvm::json::Object &object) {
 bool Breakpoint::MatchesName(const char *name) { return bp.MatchesName(name); }
 
 void Breakpoint::SetBreakpoint() {
+  lldb::SBMutex lock = dap.GetAPIMutex();
+  std::lock_guard<lldb::SBMutex> guard(lock);
+
   // See comments in BreakpointBase::GetBreakpointLabel() for details of why
   // we add a label to our breakpoints.
   bp.AddName(GetBreakpointLabel());

lldb/tools/lldb-dap/DAP.h

@@ -24,6 +24,7 @@
 #include "lldb/API/SBFile.h"
 #include "lldb/API/SBFormat.h"
 #include "lldb/API/SBFrame.h"
+#include "lldb/API/SBMutex.h"
 #include "lldb/API/SBTarget.h"
 #include "lldb/API/SBThread.h"
 #include "lldb/API/SBValue.h"
@@ -362,6 +363,8 @@ struct DAP {
 
   InstructionBreakpoint *GetInstructionBPFromStopReason(lldb::SBThread &thread);
 
+  lldb::SBMutex GetAPIMutex() const { return target.GetAPIMutex(); }
+
 private:
   // Send the JSON in "json_str" to the "out" stream. Correctly send the
   // "Content-Length:" field followed by the length, followed by the raw

lldb/tools/lldb-dap/ExceptionBreakpoint.cpp

@@ -9,7 +9,9 @@
 #include "ExceptionBreakpoint.h"
 #include "BreakpointBase.h"
 #include "DAP.h"
+#include "lldb/API/SBMutex.h"
 #include "lldb/API/SBTarget.h"
+#include <mutex>
 
 namespace lldb_dap {
 
@@ -26,6 +28,9 @@ void ExceptionBreakpoint::SetBreakpoint() {
 }
 
 void ExceptionBreakpoint::ClearBreakpoint() {
+  lldb::SBMutex lock = dap.GetAPIMutex();
+  std::lock_guard<lldb::SBMutex> guard(lock);
+
   if (!bp.IsValid())
     return;
   dap.target.BreakpointDelete(bp.GetID());

lldb/tools/lldb-dap/FunctionBreakpoint.cpp

@@ -9,13 +9,18 @@
 #include "FunctionBreakpoint.h"
 #include "DAP.h"
 #include "JSONUtils.h"
+#include "lldb/API/SBMutex.h"
+#include <mutex>
 
 namespace lldb_dap {
 
 FunctionBreakpoint::FunctionBreakpoint(DAP &d, const llvm::json::Object &obj)
     : Breakpoint(d, obj), functionName(std::string(GetString(obj, "name"))) {}
 
 void FunctionBreakpoint::SetBreakpoint() {
+  lldb::SBMutex lock = dap.GetAPIMutex();
+  std::lock_guard<lldb::SBMutex> guard(lock);
+
   if (functionName.empty())
     return;
   bp = dap.target.BreakpointCreateByName(functionName.c_str());

lldb/tools/lldb-dap/InstructionBreakpoint.cpp

@@ -11,8 +11,10 @@
 #include "DAP.h"
 #include "JSONUtils.h"
 #include "lldb/API/SBBreakpoint.h"
+#include "lldb/API/SBMutex.h"
 #include "lldb/API/SBTarget.h"
 #include "llvm/ADT/StringRef.h"
+#include <mutex>
 
 namespace lldb_dap {
 
@@ -27,6 +29,9 @@ InstructionBreakpoint::InstructionBreakpoint(DAP &d,
 }
 
 void InstructionBreakpoint::SetBreakpoint() {
+  lldb::SBMutex lock = dap.GetAPIMutex();
+  std::lock_guard<lldb::SBMutex> guard(lock);
+
   bp = dap.target.BreakpointCreateByAddress(instructionAddressReference);
   Breakpoint::SetBreakpoint();
 }

lldb/tools/lldb-dap/SourceBreakpoint.cpp

@@ -13,13 +13,15 @@
 #include "lldb/API/SBBreakpoint.h"
 #include "lldb/API/SBFileSpecList.h"
 #include "lldb/API/SBFrame.h"
+#include "lldb/API/SBMutex.h"
 #include "lldb/API/SBTarget.h"
 #include "lldb/API/SBThread.h"
 #include "lldb/API/SBValue.h"
 #include "lldb/lldb-enumerations.h"
 #include <cassert>
 #include <cctype>
 #include <cstdlib>
+#include <mutex>
 #include <utility>
 
 namespace lldb_dap {
@@ -31,6 +33,9 @@ SourceBreakpoint::SourceBreakpoint(DAP &dap, const llvm::json::Object &obj)
 }
 
 void SourceBreakpoint::SetBreakpoint(const llvm::StringRef source_path) {
+  lldb::SBMutex lock = dap.GetAPIMutex();
+  std::lock_guard<lldb::SBMutex> guard(lock);
+
   lldb::SBFileSpecList module_list;
   bp = dap.target.BreakpointCreateByLocation(source_path.str().c_str(), line,
                                              column, 0, module_list);