[swift] Fix EvaluateExpression to use the same process instance for the same stop_id

Author: kateinoigakukun

extensions/cxx_debugging/lib/ApiContext.cc

@@ -6,6 +6,7 @@
 #include "Expressions.h"
 #include "Variables.h"
 #include "WasmModule.h"
+#include "WasmVendorPlugins.h"
 #include "api.h"
 
 #include "lldb/API/SBAddress.h"
@@ -628,9 +629,31 @@ class SBValueArena {
 
 static SBValueArena arena;
 
+llvm::Expected<lldb::ProcessSP> ApiContext::GetProcess(
+    std::string stop_id,
+    std::shared_ptr<WasmModule> module,
+    const api::DebuggerProxy& proxy,
+    size_t frame_offset) {
+  lldb::ProcessSP process;
+  if (last_process_ && last_process_->process &&
+      last_process_->stop_id == stop_id) {
+    process = last_process_->process;
+  } else {
+    auto maybe_process = ::symbols_backend::CreateProcess(*module);
+    if (!maybe_process) {
+      return maybe_process.takeError();
+    }
+    process = maybe_process.get();
+    last_process_ = LastProcessInfo{process, stop_id};
+  }
+  static_cast<WasmProcess*>(process.get())
+      ->SetProxyAndFrameOffset(proxy, frame_offset);
+  return process;
+}
 
 api::EvaluateExpressionResponse ApiContext::EvaluateExpression(
     RawLocation location,
+    std::string stop_id,
     std::string expression,
     emscripten::val debug_proxy) {
   std::string raw_module_id = location.GetRawModuleId();
@@ -640,8 +663,7 @@ api::EvaluateExpressionResponse ApiContext::EvaluateExpression(
         MakeNotFoundError(raw_module_id));
   }
   DebuggerProxy proxy{debug_proxy};
-  auto process = ::symbols_backend::CreateProcess(*module, proxy,
-                                                  location.GetCodeOffset());
+  auto process = GetProcess(stop_id, module, proxy, location.GetCodeOffset());
   if (!process) {
     return api::EvaluateExpressionResponse().SetError(
         MakeError(Error::Code::kEvalError, process.takeError()));
@@ -672,6 +694,12 @@ api::GetValueSummaryResponse ApiContext::GetValueSummary(api::Sbvalue rawValue)
         .SetError(MakeError(Error::Code::kEvalError, "Invalid SBValue passed to GetValueSummary"));
   }
 
+  if (!value.IsInScope()) {
+    return api::GetValueSummaryResponse()
+        .SetDisplayValue(std::nullopt)
+        .SetError(MakeError(Error::Code::kEvalError, "SBValue is not in scope"));
+  }
+
   auto tryStringify = [&](lldb::SBValue value) -> std::optional<std::string> {
     // Use GetSummary() if available.
     if (const char *summary = value.GetSummary()) {
@@ -689,6 +717,11 @@ api::GetValueSummaryResponse ApiContext::GetValueSummary(api::Sbvalue rawValue)
     return api::GetValueSummaryResponse().SetDisplayValue(display_value);
   }
 
+  if (!value.GetError().Success()) {
+    auto err = value.GetError();
+    return api::GetValueSummaryResponse().SetError(MakeError(Error::Code::kInternalError, err.GetCString()));
+  }
+
   // If the value is a pointer or reference, dereference it and try again.
   if (value.GetType().IsPointerType() || value.GetType().IsReferenceType()) {
     if (auto display_value = tryStringify(value.Dereference())) {

extensions/cxx_debugging/lib/ApiContext.h

@@ -93,13 +93,26 @@ class ApiContext : public DWARFSymbolsApi {
 
   EvaluateExpressionResponse EvaluateExpression(
       RawLocation location,
+      std::string stop_id,
       std::string expression,
       emscripten::val debug_proxy) final;
 
  private:
   llvm::StringMap<std::shared_ptr<WasmModule>> modules_;
   llvm::StringMap<lldb_private::CompilerType> types_;
 
+  struct LastProcessInfo {
+    lldb::ProcessSP process;
+    std::string stop_id;
+  };
+  /// The last process and stop id used to evaluate an expression.
+  std::optional<LastProcessInfo> last_process_;
+
+  llvm::Expected<lldb::ProcessSP> GetProcess(std::string stop_id,
+                                             std::shared_ptr<WasmModule> module,
+                                             const api::DebuggerProxy& proxy,
+                                             size_t frame_offset);
+
   std::shared_ptr<WasmModule> AddModule(llvm::StringRef id,
                                         llvm::StringRef path);
   std::shared_ptr<WasmModule> FindModule(llvm::StringRef id) const;

extensions/cxx_debugging/lib/Expressions.cc

@@ -95,9 +95,7 @@ std::optional<llvm::Error> CheckError(lldb::SBValue value) {
   return llvm::createStringError(llvm::inconvertibleErrorCode(), message);
 }
 
-llvm::Expected<lldb::ProcessSP> CreateProcess(const WasmModule& module,
-                                             const api::DebuggerProxy& proxy,
-                                             size_t frame_offset) {
+llvm::Expected<lldb::ProcessSP> CreateProcess(const WasmModule& module) {
   auto target = module.Target()->shared_from_this();
   lldb::ListenerSP listener = lldb_private::Listener::MakeListener("wasm32");
 
@@ -112,8 +110,6 @@ llvm::Expected<lldb::ProcessSP> CreateProcess(const WasmModule& module,
           lldb::eSectionTypeCode, false);
   target->SetSectionLoadAddress(code_section, 0);
 
-  static_cast<WasmProcess*>(process.get())
-      ->SetProxyAndFrameOffset(proxy, frame_offset);
   process->UpdateThreadListIfNeeded();
   process->GetThreadList().SetSelectedThreadByID(0);
   return process;
@@ -136,8 +132,10 @@ llvm::Expected<ExpressionResult> InterpretExpression(
   WasmValueLoaderContext loader(proxy, *llvm::cast<SymbolFileWasmDWARF>(
                                            module.Module()->GetSymbolFile()));
 
+  lldb::SBFrame frame = thread->GetFrame();
+
   auto sm = lldb_eval::SourceManager::Create(expression.str());
-  auto ctx = lldb_eval::Context::Create(sm, lldb::SBFrame{thread->GetFrame()});
+  auto ctx = lldb_eval::Context::Create(sm, frame);
   lldb_eval::Parser parser(ctx);
   lldb_eval::Error e;
   auto tree = parser.Run(e);

extensions/cxx_debugging/lib/Expressions.h

@@ -41,9 +41,7 @@ struct ExpressionResult {
   std::optional<lldb::SBValue> value_object = std::nullopt;
 };
 
-llvm::Expected<lldb::ProcessSP> CreateProcess(const WasmModule& module,
-                                             const api::DebuggerProxy& proxy,
-                                             size_t frame_offset);
+llvm::Expected<lldb::ProcessSP> CreateProcess(const WasmModule& module);
 
 llvm::Expected<ExpressionResult> InterpretExpression(
     const WasmModule& module,

extensions/cxx_debugging/lib/api.h

@@ -715,6 +715,7 @@ class DWARFSymbolsApi {
 
   virtual EvaluateExpressionResponse EvaluateExpression(
     RawLocation location,
+    std::string stop_id,
     std::string expression,
     emscripten::val debug_proxy
   ) = 0;

extensions/cxx_debugging/src/DWARFSymbols.ts

@@ -404,7 +404,7 @@ export class DWARFLanguageExtensionPlugin implements Chrome.DevTools.LanguageExt
       const wasm = new Formatters.HostWasmInterface(this.hostInterface, stopId);
       const proxy = new Formatters.DebuggerProxy(wasm, moduleInfo.backend);
       const typeInfoResult =
-          manage(moduleInfo.dwarfSymbolsPlugin.EvaluateExpression(apiRawLocation, expression, proxy));
+          manage(moduleInfo.dwarfSymbolsPlugin.EvaluateExpression(apiRawLocation, String(stopId), expression, proxy));
       const error = manage(typeInfoResult.error);
       if (error) {
         if (error.code === moduleInfo.backend.ErrorCode.MODULE_NOT_FOUND_ERROR) {

extensions/cxx_debugging/src/SymbolsBackend.d.ts

@@ -166,7 +166,7 @@ export interface DWARFSymbolsPlugin extends EmbindObject {
   GetValueSummary(value: Sbvalue): GetValueSummaryResponse;
   GetValueInfo(value: Sbvalue): GetValueInfoResponse;
   GetValueChildren(value: Sbvalue): GetValueChildrenResponse;
-  EvaluateExpression(location: RawLocation,expression: string,debugProxy: unknown): EvaluateExpressionResponse;
+  EvaluateExpression(location: RawLocation,stopId: string,expression: string,debugProxy: unknown): EvaluateExpressionResponse;
 }
 
 export interface Module extends EmscriptenModule {

extensions/cxx_debugging/tools/api.pdl

@@ -245,6 +245,7 @@ domain symbols_backend
   command evaluateExpression
     parameters
       RawLocation location
+      string stopId
       string expression
       object debugProxy
     returns