[lldb] Refactor GetPreferredAsanModule() to also return the HistoryPCType

Author: yln

lldb/source/Plugins/InstrumentationRuntime/Utility/ReportRetriever.cpp

@@ -83,7 +83,7 @@ ReportRetriever::RetrieveReportData(const ProcessSP process_sp) {
   options.SetAutoApplyFixIts(false);
   options.SetLanguage(eLanguageTypeObjC_plus_plus);
 
-  if (auto m = GetPreferredAsanModule(process_sp->GetTarget())) {
+  if (auto [m, _] = GetPreferredAsanModule(process_sp->GetTarget()); m) {
     SymbolContextList sc_list;
     sc_list.Append(SymbolContext(std::move(m)));
     options.SetPreferredSymbolContexts(std::move(sc_list));

lldb/source/Plugins/InstrumentationRuntime/Utility/Utility.cpp

@@ -13,10 +13,12 @@
 
 namespace lldb_private {
 
-lldb::ModuleSP GetPreferredAsanModule(const Target &target) {
-  // Currently only supported on Darwin.
+std::tuple<lldb::ModuleSP, HistoryPCType>
+GetPreferredAsanModule(const Target &target) {
+  // Currently only Darwin provides ASan runtime support as part of the OS
+  // (libsanitizers).
   if (!target.GetArchitecture().GetTriple().isOSDarwin())
-    return nullptr;
+    return {nullptr, HistoryPCType::Calls};
 
   lldb::ModuleSP module;
   llvm::Regex pattern(R"(libclang_rt\.asan_.*_dynamic\.dylib)");
@@ -29,7 +31,16 @@ lldb::ModuleSP GetPreferredAsanModule(const Target &target) {
     return IterationAction::Continue;
   });
 
-  return module;
+  // `Calls` - The ASan compiler-rt runtime already massages the return
+  //   addresses into call addresses, so we don't want LLDB's unwinder to try to
+  //   locate the previous instruction again as this might lead to us reporting
+  //   a different line.
+  // `ReturnsNoZerothFrame` - Darwin, but not ASan compiler-rt implies
+  //   libsanitizers which collects return addresses.  It also discards a few
+  //   non-user frames at the top of the stack.
+  auto pc_type =
+      (module ? HistoryPCType::Calls : HistoryPCType::ReturnsNoZerothFrame);
+  return {module, pc_type};
 }
 
 } // namespace lldb_private

lldb/source/Plugins/InstrumentationRuntime/Utility/Utility.h

@@ -9,18 +9,20 @@
 #ifndef LLDB_SOURCE_PLUGINS_INSTRUMENTATIONRUNTIME_UTILITY_UTILITY_H
 #define LLDB_SOURCE_PLUGINS_INSTRUMENTATIONRUNTIME_UTILITY_UTILITY_H
 
+#include <tuple>
+
 #include "lldb/lldb-forward.h"
+#include "lldb/lldb-private-enumerations.h"
 
 namespace lldb_private {
 
-class Target;
-
 /// On Darwin, if LLDB loaded libclang_rt, it's coming from a locally built
 /// compiler-rt, and we should prefer it in favour of the system sanitizers
 /// when running InstrumentationRuntime utility expressions that use symbols
 /// from the sanitizer libraries. This helper searches the target for such a
 /// dylib. Returns nullptr if no such dylib was found.
-lldb::ModuleSP GetPreferredAsanModule(const Target &target);
+std::tuple<lldb::ModuleSP, HistoryPCType>
+GetPreferredAsanModule(const Target &target);
 
 } // namespace lldb_private
 

lldb/source/Plugins/MemoryHistory/asan/MemoryHistoryASan.cpp

@@ -170,24 +170,11 @@ HistoryThreads MemoryHistoryASan::GetHistoryThreads(lldb::addr_t address) {
   options.SetAutoApplyFixIts(false);
   options.SetLanguage(eLanguageTypeObjC_plus_plus);
 
-  // The ASan compiler-rt runtime already massages the return addresses into
-  // call addresses, so we don't want LLDB's unwinder to try to locate the
-  // previous instruction again as this might lead to us reporting a different
-  // line.
-  auto pc_type = HistoryPCType::Calls;
-
-  if (auto m = GetPreferredAsanModule(process_sp->GetTarget())) {
+  auto [m, pc_type] = GetPreferredAsanModule(process_sp->GetTarget());
+  if (m) {
     SymbolContextList sc_list;
     sc_list.Append(SymbolContext(std::move(m)));
     options.SetPreferredSymbolContexts(std::move(sc_list));
-  } else if (process_sp->GetTarget()
-                 .GetArchitecture()
-                 .GetTriple()
-                 .isOSDarwin()) {
-    // Darwin, but not ASan compiler-rt implies libsanitizers which collects
-    // return addresses.  It also discards a few non-user frames at the top of
-    // the stack.
-    pc_type = HistoryPCType::ReturnsNoZerothFrame;
   }
 
   ExpressionResults expr_result = UserExpression::Evaluate(