[LLDB] Add type summaries for MSVC STL strings (#143177)

This PR adds type summaries for
`std::{string,wstring,u8string,u16string,u32string}` from the MSVC STL.

See https://github.com/llvm/llvm-project/issues/24834 for the MSVC STL
issue.

The following changes were made:

- `dotest.py` now detects if the MSVC STL is available. It does so by
looking at the target triple, which is an additional argument passed
from Lit. It specifically checks for `windows-msvc` to not match on
`windows-gnu` (i.e. MinGW/Cygwin).
- (The main part): Added support for summarizing `std::(w)string` from
MSVC's STL. Because the type names from the libstdc++ (pre C++ 11)
string types are the same as on MSVC's STL, `CXXCompositeSummaryFormat`
is used with two entries, one for MSVC's STL and one for libstdc++.
With MSVC's STL, `std::u{8,16,32}string` is also handled. These aren't
handled for libstdc++, so I put them in `LoadMsvcStlFormatters`.

1 files changed, 109 insertions, 29 deletions

diff --git a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
index e64b3eb..17963c0 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
+++ b/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;
@@ -1331,6 +1332,37 @@ static void LoadLibCxxFormatters(lldb::TypeCategoryImplSP cpp_category_sp) {
           "${var.__y_} ${var.__m_} ${var.__wdl_}")));
 }
 
+static void RegisterStdStringSummaryProvider(
+    const lldb::TypeCategoryImplSP &category_sp, llvm::StringRef string_ty,
+    llvm::StringRef char_ty, lldb::TypeSummaryImplSP summary_sp) {
+  auto makeSpecifier = [](llvm::StringRef name) {
+    return std::make_shared<lldb_private::TypeNameSpecifierImpl>(
+        name, eFormatterMatchExact);
+  };
+
+  category_sp->AddTypeSummary(makeSpecifier(string_ty), summary_sp);
+
+  // std::basic_string<char>
+  category_sp->AddTypeSummary(
+      makeSpecifier(llvm::formatv("std::basic_string<{}>", char_ty).str()),
+      summary_sp);
+  // std::basic_string<char,std::char_traits<char>,std::allocator<char> >
+  category_sp->AddTypeSummary(
+      makeSpecifier(llvm::formatv("std::basic_string<{0},std::char_traits<{0}>,"
+                                  "std::allocator<{0}> >",
+                                  char_ty)
+                        .str()),
+      summary_sp);
+  // std::basic_string<char, std::char_traits<char>, std::allocator<char> >
+  category_sp->AddTypeSummary(
+      makeSpecifier(
+          llvm::formatv("std::basic_string<{0}, std::char_traits<{0}>, "
+                        "std::allocator<{0}> >",
+                        char_ty)
+              .str()),
+      summary_sp);
+}
+
 static void LoadLibStdcppFormatters(lldb::TypeCategoryImplSP cpp_category_sp) {
   if (!cpp_category_sp)
     return;
@@ -1347,18 +1379,6 @@ static void LoadLibStdcppFormatters(lldb::TypeCategoryImplSP cpp_category_sp) {
   lldb::TypeSummaryImplSP string_summary_sp(new CXXFunctionSummaryFormat(
       stl_summary_flags, LibStdcppStringSummaryProvider,
       "libstdc++ std::(w)string summary provider"));
-
-  cpp_category_sp->AddTypeSummary("std::string", eFormatterMatchExact,
-                                  string_summary_sp);
-  cpp_category_sp->AddTypeSummary("std::basic_string<char>",
-                                  eFormatterMatchExact, string_summary_sp);
-  cpp_category_sp->AddTypeSummary(
-      "std::basic_string<char,std::char_traits<char>,std::allocator<char> >",
-      eFormatterMatchExact, string_summary_sp);
-  cpp_category_sp->AddTypeSummary(
-      "std::basic_string<char, std::char_traits<char>, std::allocator<char> >",
-      eFormatterMatchExact, string_summary_sp);
-
   cpp_category_sp->AddTypeSummary("std::__cxx11::string", eFormatterMatchExact,
                                   string_summary_sp);
   cpp_category_sp->AddTypeSummary(
@@ -1370,23 +1390,6 @@ static void LoadLibStdcppFormatters(lldb::TypeCategoryImplSP cpp_category_sp) {
                                   "std::allocator<unsigned char> >",
                                   eFormatterMatchExact, 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, "${var._M_dataplus._M_p%S}"));
-
-  cpp_category_sp->AddTypeSummary("std::wstring", eFormatterMatchExact,
-                                  std_wstring_summary_sp);
-  cpp_category_sp->AddTypeSummary("std::basic_string<wchar_t>",
-                                  eFormatterMatchExact, std_wstring_summary_sp);
-  cpp_category_sp->AddTypeSummary("std::basic_string<wchar_t,std::char_traits<"
-                                  "wchar_t>,std::allocator<wchar_t> >",
-                                  eFormatterMatchExact, std_wstring_summary_sp);
-  cpp_category_sp->AddTypeSummary(
-      "std::basic_string<wchar_t, std::char_traits<wchar_t>, "
-      "std::allocator<wchar_t> >",
-      eFormatterMatchExact, std_wstring_summary_sp);
-
   cpp_category_sp->AddTypeSummary("std::__cxx11::wstring", eFormatterMatchExact,
                                   string_summary_sp);
   cpp_category_sp->AddTypeSummary(
@@ -1595,6 +1598,81 @@ static void LoadLibStdcppFormatters(lldb::TypeCategoryImplSP cpp_category_sp) {
                 "^std::optional<.+>(( )?&)?$", stl_summary_flags, true);
 }
 
+/// Load formatters that are formatting types from more than one STL
+static void LoadCommonStlFormatters(lldb::TypeCategoryImplSP cpp_category_sp) {
+  if (!cpp_category_sp)
+    return;
+
+  TypeSummaryImpl::Flags stl_summary_flags;
+  stl_summary_flags.SetCascades(true)
+      .SetSkipPointers(false)
+      .SetSkipReferences(false)
+      .SetDontShowChildren(true)
+      .SetDontShowValue(false)
+      .SetShowMembersOneLiner(false)
+      .SetHideItemNames(false);
+  using StringElementType = StringPrinter::StringElementType;
+
+  RegisterStdStringSummaryProvider(
+      cpp_category_sp, "std::string", "char",
+      std::make_shared<CXXFunctionSummaryFormat>(
+          stl_summary_flags,
+          [](ValueObject &valobj, Stream &stream,
+             const TypeSummaryOptions &options) {
+            if (IsMsvcStlStringType(valobj))
+              return MsvcStlStringSummaryProvider<StringElementType::ASCII>(
+                  valobj, stream, options);
+            return LibStdcppStringSummaryProvider(valobj, stream, options);
+          },
+          "MSVC STL/libstdc++ std::string summary provider"));
+  RegisterStdStringSummaryProvider(
+      cpp_category_sp, "std::wstring", "wchar_t",
+      std::make_shared<CXXFunctionSummaryFormat>(
+          stl_summary_flags,
+          [](ValueObject &valobj, Stream &stream,
+             const TypeSummaryOptions &options) {
+            if (IsMsvcStlStringType(valobj))
+              return MsvcStlWStringSummaryProvider(valobj, stream, options);
+            return LibStdcppStringSummaryProvider(valobj, stream, options);
+          },
+          "MSVC STL/libstdc++ std::wstring summary provider"));
+}
+
+static void LoadMsvcStlFormatters(lldb::TypeCategoryImplSP cpp_category_sp) {
+  if (!cpp_category_sp)
+    return;
+
+  TypeSummaryImpl::Flags stl_summary_flags;
+  stl_summary_flags.SetCascades(true)
+      .SetSkipPointers(false)
+      .SetSkipReferences(false)
+      .SetDontShowChildren(true)
+      .SetDontShowValue(false)
+      .SetShowMembersOneLiner(false)
+      .SetHideItemNames(false);
+
+  using StringElementType = StringPrinter::StringElementType;
+
+  RegisterStdStringSummaryProvider(
+      cpp_category_sp, "std::u8string", "char8_t",
+      std::make_shared<CXXFunctionSummaryFormat>(
+          stl_summary_flags,
+          MsvcStlStringSummaryProvider<StringElementType::UTF8>,
+          "MSVC STL std::u8string summary provider"));
+  RegisterStdStringSummaryProvider(
+      cpp_category_sp, "std::u16string", "char16_t",
+      std::make_shared<CXXFunctionSummaryFormat>(
+          stl_summary_flags,
+          MsvcStlStringSummaryProvider<StringElementType::UTF16>,
+          "MSVC STL std::u16string summary provider"));
+  RegisterStdStringSummaryProvider(
+      cpp_category_sp, "std::u32string", "char32_t",
+      std::make_shared<CXXFunctionSummaryFormat>(
+          stl_summary_flags,
+          MsvcStlStringSummaryProvider<StringElementType::UTF32>,
+          "MSVC STL std::u32string summary provider"));
+}
+
 static void LoadSystemFormatters(lldb::TypeCategoryImplSP cpp_category_sp) {
   if (!cpp_category_sp)
     return;
@@ -1709,6 +1787,8 @@ lldb::TypeCategoryImplSP CPlusPlusLanguage::GetFormatters() {
       // LLDB prioritizes the last loaded matching formatter.
       LoadLibCxxFormatters(g_category);
       LoadLibStdcppFormatters(g_category);
+      LoadMsvcStlFormatters(g_category);
+      LoadCommonStlFormatters(g_category);
       LoadSystemFormatters(g_category);
     }
   });