[LLDB] Add type summaries for MSVC STL strings

Author: Nerixyz

lldb/include/lldb/DataFormatters/StringPrinter.h

@@ -152,6 +152,21 @@ class StringPrinter {
   template <StringElementType element_type>
   static bool
   ReadBufferAndDumpToStream(const ReadBufferAndDumpToStreamOptions &options);
+
+  template <StringElementType element_type>
+  static constexpr uint64_t ElementByteSize() {
+    switch (element_type) {
+    case StringElementType::ASCII:
+    case StringElementType::UTF8:
+      return 1;
+    case StringElementType::UTF16:
+      return 2;
+    case StringElementType::UTF32:
+      return 3;
+    default:
+      return 0;
+    }
+  }
 };
 
 } // namespace formatters

lldb/packages/Python/lldbsuite/test/dotest.py

@@ -831,6 +831,26 @@ def checkLibstdcxxSupport():
     configuration.skip_categories.append("libstdcxx")
 
 
+def canRunMsvcStlTests():
+    from lldbsuite.test import lldbplatformutil
+
+    platform = lldbplatformutil.getPlatform()
+    if platform == "windows":
+        return True, "MSVC STL is present on Windows"
+    return False, f"Don't know how to build with MSVC's STL on {platform}"
+
+
+def checkMsvcStlSupport():
+    result, reason = canRunMsvcStlTests()
+    if result:
+        return  # msvcstl supported
+    if "msvcstl" in configuration.categories_list:
+        return  # msvcstl category explicitly requested, let it run.
+    if configuration.verbose:
+        print(f"msvcstl tests will not be run because: {reason}")
+    configuration.skip_categories.append("msvcstl")
+
+
 def canRunWatchpointTests():
     from lldbsuite.test import lldbplatformutil
 
@@ -1044,6 +1064,7 @@ def run_suite():
 
     checkLibcxxSupport()
     checkLibstdcxxSupport()
+    checkMsvcStlSupport()
     checkWatchpointSupport()
     checkDebugInfoSupport()
     checkDebugServerSupport()

lldb/packages/Python/lldbsuite/test/test_categories.py

@@ -33,6 +33,7 @@
     "lldb-server": "Tests related to lldb-server",
     "lldb-dap": "Tests for the Debug Adapter Protocol with lldb-dap",
     "llgs": "Tests for the gdb-server functionality of lldb-server",
+    "msvcstl": "Test for MSVC STL data formatters",
     "pexpect": "Tests requiring the pexpect library to be available",
     "objc": "Tests related to the Objective-C programming language support",
     "pyapi": "Tests related to the Python API",

lldb/source/Plugins/Language/CPlusPlus/CMakeLists.txt

@@ -32,6 +32,7 @@ add_lldb_library(lldbPluginCPlusPlusLanguage PLUGIN
   LibStdcpp.cpp
   LibStdcppTuple.cpp
   LibStdcppUniquePointer.cpp
+  MsvcStl.cpp
   MSVCUndecoratedNameParser.cpp
 
   LINK_COMPONENTS

lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp

@@ -46,6 +46,7 @@
 #include "LibCxxVariant.h"
 #include "LibStdcpp.h"
 #include "MSVCUndecoratedNameParser.h"
+#include "MsvcStl.h"
 #include "lldb/lldb-enumerations.h"
 
 using namespace lldb;
@@ -1372,6 +1373,56 @@ static void LoadLibCxxFormatters(lldb::TypeCategoryImplSP cpp_category_sp) {
           "${var.__y_} ${var.__m_} ${var.__wdl_}")));
 }
 
+template <StringPrinter::StringElementType element_type>
+static bool
+LibstdcppOrMsvcStringSummaryProvider(ValueObject &valobj, Stream &stream,
+                                     const TypeSummaryOptions &options) {
+  ValueObjectSP libstdcpp = valobj.GetChildMemberWithName("_M_dataplus");
+  if (libstdcpp) {
+    ValueObjectSP ptr = libstdcpp->GetChildMemberWithName("_M_p");
+    if (!ptr)
+      return false;
+    return CharTStringSummaryProvider<element_type>(*ptr, stream);
+  }
+  return MsvcStlStringSummaryProvider<element_type>(valobj, stream, options);
+}
+
+static bool
+LibstdcppOrMsvcWStringSummaryProvider(ValueObject &valobj, Stream &stream,
+                                      const TypeSummaryOptions &options) {
+  ValueObjectSP libstdcpp = valobj.GetChildMemberWithName("_M_dataplus");
+  if (libstdcpp) {
+    ValueObjectSP ptr = libstdcpp->GetChildMemberWithName("_M_p");
+    if (!ptr)
+      return false;
+    return WCharStringSummaryProvider(*ptr, stream, options);
+  }
+  return MsvcStlWStringSummaryProvider(valobj, stream, options);
+}
+
+static void RegisterLibstdcppOrMsvcStringSummaryProvider(
+    const lldb::TypeCategoryImplSP &category_sp, llvm::StringRef string_ty,
+    llvm::StringRef char_ty, const lldb::TypeSummaryImplSP &summary_sp) {
+  category_sp->AddTypeSummary(string_ty, eFormatterMatchExact, summary_sp);
+
+  // std::basic_string<char>
+  category_sp->AddTypeSummary(
+      (llvm::Twine("std::basic_string<") + char_ty + ">").str(),
+      eFormatterMatchExact, summary_sp);
+  // std::basic_string<char,std::char_traits<char>,std::allocator<char> >
+  category_sp->AddTypeSummary((llvm::Twine("std::basic_string<") + char_ty +
+                               ",std::char_traits<" + char_ty +
+                               ">,std::allocator<" + char_ty + "> >")
+                                  .str(),
+                              eFormatterMatchExact, summary_sp);
+  // std::basic_string<char, std::char_traits<char>, std::allocator<char> >
+  category_sp->AddTypeSummary((llvm::Twine("std::basic_string<") + char_ty +
+                               ", std::char_traits<" + char_ty +
+                               ">, std::allocator<" + char_ty + "> >")
+                                  .str(),
+                              eFormatterMatchExact, summary_sp);
+}
+
 static void LoadLibStdcppFormatters(lldb::TypeCategoryImplSP cpp_category_sp) {
   if (!cpp_category_sp)
     return;
@@ -1385,26 +1436,20 @@ static void LoadLibStdcppFormatters(lldb::TypeCategoryImplSP cpp_category_sp) {
       .SetShowMembersOneLiner(false)
       .SetHideItemNames(false);
 
-  lldb::TypeSummaryImplSP std_string_summary_sp(
-      new StringSummaryFormat(stl_summary_flags, "${var._M_dataplus._M_p}"));
-
   lldb::TypeSummaryImplSP cxx11_string_summary_sp(new CXXFunctionSummaryFormat(
       stl_summary_flags, LibStdcppStringSummaryProvider,
       "libstdc++ c++11 std::string summary provider"));
   lldb::TypeSummaryImplSP cxx11_wstring_summary_sp(new CXXFunctionSummaryFormat(
       stl_summary_flags, LibStdcppWStringSummaryProvider,
       "libstdc++ c++11 std::wstring summary provider"));
 
-  cpp_category_sp->AddTypeSummary("std::string", eFormatterMatchExact,
-                                  std_string_summary_sp);
-  cpp_category_sp->AddTypeSummary("std::basic_string<char>",
-                                  eFormatterMatchExact, std_string_summary_sp);
-  cpp_category_sp->AddTypeSummary(
-      "std::basic_string<char,std::char_traits<char>,std::allocator<char> >",
-      eFormatterMatchExact, std_string_summary_sp);
-  cpp_category_sp->AddTypeSummary(
-      "std::basic_string<char, std::char_traits<char>, std::allocator<char> >",
-      eFormatterMatchExact, std_string_summary_sp);
+  RegisterLibstdcppOrMsvcStringSummaryProvider(
+      cpp_category_sp, "std::string", "char",
+      lldb::TypeSummaryImplSP(new CXXFunctionSummaryFormat(
+          stl_summary_flags,
+          LibstdcppOrMsvcStringSummaryProvider<
+              StringPrinter::StringElementType::ASCII>,
+          "libstdc++/MSVC STL std::string summary provider")));
 
   cpp_category_sp->AddTypeSummary("std::__cxx11::string", eFormatterMatchExact,
                                   cxx11_string_summary_sp);
@@ -1418,22 +1463,11 @@ static void LoadLibStdcppFormatters(lldb::TypeCategoryImplSP cpp_category_sp) {
                                   eFormatterMatchExact,
                                   cxx11_string_summary_sp);
 
-  // making sure we force-pick the summary for printing wstring (_M_p is a
-  // wchar_t*)
-  lldb::TypeSummaryImplSP std_wstring_summary_sp(
-      new StringSummaryFormat(stl_summary_flags, "${var._M_dataplus._M_p%S}"));
-
-  cpp_category_sp->AddTypeSummary("std::wstring", eFormatterMatchExact,
-                                  std_wstring_summary_sp);
-  cpp_category_sp->AddTypeSummary("std::basic_string<wchar_t>",
-                                  eFormatterMatchExact, std_wstring_summary_sp);
-  cpp_category_sp->AddTypeSummary("std::basic_string<wchar_t,std::char_traits<"
-                                  "wchar_t>,std::allocator<wchar_t> >",
-                                  eFormatterMatchExact, std_wstring_summary_sp);
-  cpp_category_sp->AddTypeSummary(
-      "std::basic_string<wchar_t, std::char_traits<wchar_t>, "
-      "std::allocator<wchar_t> >",
-      eFormatterMatchExact, std_wstring_summary_sp);
+  RegisterLibstdcppOrMsvcStringSummaryProvider(
+      cpp_category_sp, "std::wstring", "wchar_t",
+      lldb::TypeSummaryImplSP(new CXXFunctionSummaryFormat(
+          stl_summary_flags, LibstdcppOrMsvcWStringSummaryProvider,
+          "libstdc++/MSVC STL std::wstring summary provider")));
 
   cpp_category_sp->AddTypeSummary("std::__cxx11::wstring", eFormatterMatchExact,
                                   cxx11_wstring_summary_sp);
@@ -1442,6 +1476,28 @@ static void LoadLibStdcppFormatters(lldb::TypeCategoryImplSP cpp_category_sp) {
       "std::allocator<wchar_t> >",
       eFormatterMatchExact, cxx11_wstring_summary_sp);
 
+  RegisterLibstdcppOrMsvcStringSummaryProvider(
+      cpp_category_sp, "std::u8string", "char8_t",
+      lldb::TypeSummaryImplSP(new CXXFunctionSummaryFormat(
+          stl_summary_flags,
+          LibstdcppOrMsvcStringSummaryProvider<
+              StringPrinter::StringElementType::UTF8>,
+          "libstdc++/MSVC STL std::u8string summary provider")));
+  RegisterLibstdcppOrMsvcStringSummaryProvider(
+      cpp_category_sp, "std::u16string", "char16_t",
+      lldb::TypeSummaryImplSP(new CXXFunctionSummaryFormat(
+          stl_summary_flags,
+          LibstdcppOrMsvcStringSummaryProvider<
+              StringPrinter::StringElementType::UTF16>,
+          "libstdc++/MSVC STL std::u16string summary provider")));
+  RegisterLibstdcppOrMsvcStringSummaryProvider(
+      cpp_category_sp, "std::u32string", "char32_t",
+      lldb::TypeSummaryImplSP(new CXXFunctionSummaryFormat(
+          stl_summary_flags,
+          LibstdcppOrMsvcStringSummaryProvider<
+              StringPrinter::StringElementType::UTF32>,
+          "libstdc++/MSVC STL std::u32string summary provider")));
+
   SyntheticChildren::Flags stl_synth_flags;
   stl_synth_flags.SetCascades(true).SetSkipPointers(false).SetSkipReferences(
       false);