[Lldb-commits] [lldb] [lldb] upgrade HandleFrameFormatVariable callees to llvm::Expected (PR #144731)

Charles Zablit via lldb-commits lldb-commits at lists.llvm.org
Thu Jun 19 06:54:38 PDT 2025


https://github.com/charles-zablit updated https://github.com/llvm/llvm-project/pull/144731

>From 3c9a3e5e9af0c9d58783c11490bda473ada84ef3 Mon Sep 17 00:00:00 2001
From: Charles Zablit <c_zablit at apple.com>
Date: Wed, 18 Jun 2025 16:41:40 +0100
Subject: [PATCH 1/5] [lldb] upgrade HandleFrameFormatVariable callees to
 llvm::Expected

---
 .../Language/CPlusPlus/CPlusPlusLanguage.cpp  | 266 ++++++++----------
 1 file changed, 110 insertions(+), 156 deletions(-)

diff --git a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
index 0f18abb47591d..1810c07652a2b 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
@@ -236,199 +236,140 @@ static bool PrettyPrintFunctionNameWithArgs(Stream &out_stream,
   return true;
 }
 
-static std::optional<llvm::StringRef>
-GetDemangledBasename(const SymbolContext &sc) {
+static llvm::Expected<std::pair<llvm::StringRef, DemangledNameInfo>>
+GetAndValidateInfo(const SymbolContext &sc) {
   Mangled mangled = sc.GetPossiblyInlinedFunctionName();
   if (!mangled)
-    return std::nullopt;
+    return llvm::createStringError("Function does not have a mangled name.");
 
   auto demangled_name = mangled.GetDemangledName().GetStringRef();
   if (demangled_name.empty())
-    return std::nullopt;
+    return llvm::createStringError("Function does not have a demangled name.");
 
   const std::optional<DemangledNameInfo> &info = mangled.GetDemangledInfo();
   if (!info)
-    return std::nullopt;
+    return llvm::createStringError("Function does not have demangled info.");
 
   // Function without a basename is nonsense.
   if (!info->hasBasename())
-    return std::nullopt;
+    return llvm::createStringError("Info do not have basename range.");
 
-  return demangled_name.slice(info->BasenameRange.first,
-                              info->BasenameRange.second);
+  return std::make_pair(demangled_name, *info);
 }
 
-static std::optional<llvm::StringRef>
-GetDemangledTemplateArguments(const SymbolContext &sc) {
-  Mangled mangled = sc.GetPossiblyInlinedFunctionName();
-  if (!mangled)
-    return std::nullopt;
+static llvm::Expected<llvm::StringRef>
+GetDemangledBasename(const SymbolContext &sc) {
+  auto info_or_err = GetAndValidateInfo(sc);
+  if (!info_or_err)
+    return info_or_err.takeError();
 
-  auto demangled_name = mangled.GetDemangledName().GetStringRef();
-  if (demangled_name.empty())
-    return std::nullopt;
+  auto [demangled_name, info] = *info_or_err;
 
-  const std::optional<DemangledNameInfo> &info = mangled.GetDemangledInfo();
-  if (!info)
-    return std::nullopt;
+  return demangled_name.slice(info.BasenameRange.first,
+                              info.BasenameRange.second);
+}
 
-  // Function without a basename is nonsense.
-  if (!info->hasBasename())
-    return std::nullopt;
+static llvm::Expected<llvm::StringRef>
+GetDemangledTemplateArguments(const SymbolContext &sc) {
+  auto info_or_err = GetAndValidateInfo(sc);
+  if (!info_or_err)
+    return info_or_err.takeError();
+
+  auto [demangled_name, info] = *info_or_err;
 
-  if (info->ArgumentsRange.first < info->BasenameRange.second)
-    return std::nullopt;
+  if (info.ArgumentsRange.first < info.BasenameRange.second)
+    return llvm::createStringError("Arguments in info are invalid.");
 
-  return demangled_name.slice(info->BasenameRange.second,
-                              info->ArgumentsRange.first);
+  return demangled_name.slice(info.BasenameRange.second,
+                              info.ArgumentsRange.first);
 }
 
-static std::optional<llvm::StringRef>
+static llvm::Expected<llvm::StringRef>
 GetDemangledReturnTypeLHS(const SymbolContext &sc) {
-  Mangled mangled = sc.GetPossiblyInlinedFunctionName();
-  if (!mangled)
-    return std::nullopt;
+  auto info_or_err = GetAndValidateInfo(sc);
+  if (!info_or_err)
+    return info_or_err.takeError();
 
-  auto demangled_name = mangled.GetDemangledName().GetStringRef();
-  if (demangled_name.empty())
-    return std::nullopt;
+  auto [demangled_name, info] = *info_or_err;
 
-  const std::optional<DemangledNameInfo> &info = mangled.GetDemangledInfo();
-  if (!info)
-    return std::nullopt;
+  if (info.ScopeRange.first >= demangled_name.size())
+    return llvm::createStringError("Scope range is invalid.");
 
-  // Function without a basename is nonsense.
-  if (!info->hasBasename())
-    return std::nullopt;
-
-  if (info->ScopeRange.first >= demangled_name.size())
-    return std::nullopt;
-
-  return demangled_name.substr(0, info->ScopeRange.first);
+  return demangled_name.substr(0, info.ScopeRange.first);
 }
 
-static std::optional<llvm::StringRef>
+static llvm::Expected<llvm::StringRef>
 GetDemangledFunctionQualifiers(const SymbolContext &sc) {
-  Mangled mangled = sc.GetPossiblyInlinedFunctionName();
-  if (!mangled)
-    return std::nullopt;
+  auto info_or_err = GetAndValidateInfo(sc);
+  if (!info_or_err)
+    return info_or_err.takeError();
 
-  auto demangled_name = mangled.GetDemangledName().GetStringRef();
-  if (demangled_name.empty())
-    return std::nullopt;
+  auto [demangled_name, info] = *info_or_err;
 
-  const std::optional<DemangledNameInfo> &info = mangled.GetDemangledInfo();
-  if (!info)
-    return std::nullopt;
-
-  // Function without a basename is nonsense.
-  if (!info->hasBasename())
-    return std::nullopt;
+  if (info.QualifiersRange.second < info.QualifiersRange.first)
+    return llvm::createStringError("Qualifiers range is invalid.");
 
-  if (info->QualifiersRange.second < info->QualifiersRange.first)
-    return std::nullopt;
-
-  return demangled_name.slice(info->QualifiersRange.first,
-                              info->QualifiersRange.second);
+  return demangled_name.slice(info.QualifiersRange.first,
+                              info.QualifiersRange.second);
 }
 
-static std::optional<llvm::StringRef>
+static llvm::Expected<llvm::StringRef>
 GetDemangledReturnTypeRHS(const SymbolContext &sc) {
-  Mangled mangled = sc.GetPossiblyInlinedFunctionName();
-  if (!mangled)
-    return std::nullopt;
-
-  auto demangled_name = mangled.GetDemangledName().GetStringRef();
-  if (demangled_name.empty())
-    return std::nullopt;
+  auto info_or_err = GetAndValidateInfo(sc);
+  if (!info_or_err)
+    return info_or_err.takeError();
 
-  const std::optional<DemangledNameInfo> &info = mangled.GetDemangledInfo();
-  if (!info)
-    return std::nullopt;
-
-  // Function without a basename is nonsense.
-  if (!info->hasBasename())
-    return std::nullopt;
+  auto [demangled_name, info] = *info_or_err;
 
-  if (info->QualifiersRange.first < info->ArgumentsRange.second)
-    return std::nullopt;
+  if (info.QualifiersRange.first < info.ArgumentsRange.second)
+    return llvm::createStringError("Qualifiers range is invalid.");
 
-  return demangled_name.slice(info->ArgumentsRange.second,
-                              info->QualifiersRange.first);
+  return demangled_name.slice(info.ArgumentsRange.second,
+                              info.QualifiersRange.first);
 }
 
-static std::optional<llvm::StringRef>
+static llvm::Expected<llvm::StringRef>
 GetDemangledScope(const SymbolContext &sc) {
-  Mangled mangled = sc.GetPossiblyInlinedFunctionName();
-  if (!mangled)
-    return std::nullopt;
-
-  auto demangled_name = mangled.GetDemangledName().GetStringRef();
-  if (demangled_name.empty())
-    return std::nullopt;
+  auto info_or_err = GetAndValidateInfo(sc);
+  if (!info_or_err)
+    return info_or_err.takeError();
 
-  const std::optional<DemangledNameInfo> &info = mangled.GetDemangledInfo();
-  if (!info)
-    return std::nullopt;
-
-  // Function without a basename is nonsense.
-  if (!info->hasBasename())
-    return std::nullopt;
+  auto [demangled_name, info] = *info_or_err;
 
-  if (info->ScopeRange.second < info->ScopeRange.first)
-    return std::nullopt;
+  if (info.ScopeRange.second < info.ScopeRange.first)
+    return llvm::createStringError("Info do not have basename range.");
 
-  return demangled_name.slice(info->ScopeRange.first, info->ScopeRange.second);
+  return demangled_name.slice(info.ScopeRange.first, info.ScopeRange.second);
 }
 
 /// Handles anything printed after the FunctionEncoding ItaniumDemangle
 /// node. Most notably the DotSUffix node.
-static std::optional<llvm::StringRef>
+static llvm::Expected<llvm::StringRef>
 GetDemangledFunctionSuffix(const SymbolContext &sc) {
-  Mangled mangled = sc.GetPossiblyInlinedFunctionName();
-  if (!mangled)
-    return std::nullopt;
+  auto info_or_err = GetAndValidateInfo(sc);
+  if (!info_or_err)
+    return info_or_err.takeError();
 
-  auto demangled_name = mangled.GetDemangledName().GetStringRef();
-  if (demangled_name.empty())
-    return std::nullopt;
+  auto [demangled_name, info] = *info_or_err;
 
-  const std::optional<DemangledNameInfo> &info = mangled.GetDemangledInfo();
-  if (!info)
-    return std::nullopt;
-
-  // Function without a basename is nonsense.
-  if (!info->hasBasename())
-    return std::nullopt;
-
-  return demangled_name.slice(info->SuffixRange.first,
-                              info->SuffixRange.second);
+  return demangled_name.slice(info.SuffixRange.first, info.SuffixRange.second);
 }
 
 static bool PrintDemangledArgumentList(Stream &s, const SymbolContext &sc) {
   assert(sc.symbol);
 
-  Mangled mangled = sc.GetPossiblyInlinedFunctionName();
-  if (!mangled)
-    return false;
-
-  auto demangled_name = mangled.GetDemangledName().GetStringRef();
-  if (demangled_name.empty())
-    return false;
-
-  const std::optional<DemangledNameInfo> &info = mangled.GetDemangledInfo();
-  if (!info)
-    return false;
-
-  // Function without a basename is nonsense.
-  if (!info->hasBasename())
+  auto info_or_err = GetAndValidateInfo(sc);
+  if (!info_or_err) {
+    info_or_err.takeError();
     return false;
+  }
+  auto [demangled_name, info] = *info_or_err;
 
-  if (info->ArgumentsRange.second < info->ArgumentsRange.first)
+  if (info.ArgumentsRange.second < info.ArgumentsRange.first)
     return false;
 
-  s << demangled_name.slice(info->ArgumentsRange.first,
-                            info->ArgumentsRange.second);
+  s << demangled_name.slice(info.ArgumentsRange.first,
+                            info.ArgumentsRange.second);
 
   return true;
 }
@@ -1954,32 +1895,37 @@ bool CPlusPlusLanguage::HandleFrameFormatVariable(
     FormatEntity::Entry::Type type, Stream &s) {
   switch (type) {
   case FormatEntity::Entry::Type::FunctionScope: {
-    std::optional<llvm::StringRef> scope = GetDemangledScope(sc);
-    if (!scope)
+    auto scope_or_err = GetDemangledScope(sc);
+    if (!scope_or_err) {
+      llvm::consumeError(scope_or_err.takeError());
       return false;
+    }
 
-    s << *scope;
+    s << *scope_or_err;
 
     return true;
   }
 
   case FormatEntity::Entry::Type::FunctionBasename: {
-    std::optional<llvm::StringRef> name = GetDemangledBasename(sc);
-    if (!name)
+    auto name_or_err = GetDemangledBasename(sc);
+    if (!name_or_err) {
+      llvm::consumeError(name_or_err.takeError());
       return false;
+    }
 
-    s << *name;
+    s << *name_or_err;
 
     return true;
   }
 
   case FormatEntity::Entry::Type::FunctionTemplateArguments: {
-    std::optional<llvm::StringRef> template_args =
-        GetDemangledTemplateArguments(sc);
-    if (!template_args)
+    auto template_args_or_err = GetDemangledTemplateArguments(sc);
+    if (!template_args_or_err) {
+      llvm::consumeError(template_args_or_err.takeError());
       return false;
+    }
 
-    s << *template_args;
+    s << *template_args_or_err;
 
     return true;
   }
@@ -2008,38 +1954,46 @@ bool CPlusPlusLanguage::HandleFrameFormatVariable(
     return true;
   }
   case FormatEntity::Entry::Type::FunctionReturnRight: {
-    std::optional<llvm::StringRef> return_rhs = GetDemangledReturnTypeRHS(sc);
-    if (!return_rhs)
+    auto return_rhs_or_err = GetDemangledReturnTypeRHS(sc);
+    if (!return_rhs_or_err) {
+      llvm::consumeError(return_rhs_or_err.takeError());
       return false;
+    }
 
-    s << *return_rhs;
+    s << *return_rhs_or_err;
 
     return true;
   }
   case FormatEntity::Entry::Type::FunctionReturnLeft: {
-    std::optional<llvm::StringRef> return_lhs = GetDemangledReturnTypeLHS(sc);
-    if (!return_lhs)
+    auto return_lhs_or_err = GetDemangledReturnTypeLHS(sc);
+    if (!return_lhs_or_err) {
+      llvm::consumeError(return_lhs_or_err.takeError());
       return false;
+    }
 
-    s << *return_lhs;
+    s << *return_lhs_or_err;
 
     return true;
   }
   case FormatEntity::Entry::Type::FunctionQualifiers: {
-    std::optional<llvm::StringRef> quals = GetDemangledFunctionQualifiers(sc);
-    if (!quals)
+    auto quals_or_err = GetDemangledFunctionQualifiers(sc);
+    if (!quals_or_err) {
+      llvm::consumeError(quals_or_err.takeError());
       return false;
+    }
 
-    s << *quals;
+    s << *quals_or_err;
 
     return true;
   }
   case FormatEntity::Entry::Type::FunctionSuffix: {
-    std::optional<llvm::StringRef> suffix = GetDemangledFunctionSuffix(sc);
-    if (!suffix)
+    auto suffix_or_err = GetDemangledFunctionSuffix(sc);
+    if (!suffix_or_err) {
+      llvm::consumeError(suffix_or_err.takeError());
       return false;
+    }
 
-    s << *suffix;
+    s << *suffix_or_err;
 
     return true;
   }

>From 9000c4d889aa815ea06042f3aab7118c624c9d16 Mon Sep 17 00:00:00 2001
From: Charles Zablit <c_zablit at apple.com>
Date: Wed, 18 Jun 2025 16:55:49 +0100
Subject: [PATCH 2/5] fixup! [lldb] upgrade HandleFrameFormatVariable callees
 to llvm::Expected

---
 lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
index 1810c07652a2b..5859f07659297 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
@@ -360,7 +360,7 @@ static bool PrintDemangledArgumentList(Stream &s, const SymbolContext &sc) {
 
   auto info_or_err = GetAndValidateInfo(sc);
   if (!info_or_err) {
-    info_or_err.takeError();
+    llvm::consumeError(info_or_err.takeError());
     return false;
   }
   auto [demangled_name, info] = *info_or_err;

>From b0e4f74f4adb3e578a968d3ae9ee0809b80c6d46 Mon Sep 17 00:00:00 2001
From: Charles Zablit <c_zablit at apple.com>
Date: Wed, 18 Jun 2025 18:16:51 +0100
Subject: [PATCH 3/5] log the error instead of just consuming it

---
 .../Language/CPlusPlus/CPlusPlusLanguage.cpp  | 25 +++++++++++++------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
index 5859f07659297..20ecac44eafd2 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
@@ -360,7 +360,8 @@ static bool PrintDemangledArgumentList(Stream &s, const SymbolContext &sc) {
 
   auto info_or_err = GetAndValidateInfo(sc);
   if (!info_or_err) {
-    llvm::consumeError(info_or_err.takeError());
+    LLDB_LOG_ERROR(GetLog(LLDBLog::Language), info_or_err.takeError(),
+                   "Failed to retrieve demangled info: {0}");
     return false;
   }
   auto [demangled_name, info] = *info_or_err;
@@ -1897,7 +1898,8 @@ bool CPlusPlusLanguage::HandleFrameFormatVariable(
   case FormatEntity::Entry::Type::FunctionScope: {
     auto scope_or_err = GetDemangledScope(sc);
     if (!scope_or_err) {
-      llvm::consumeError(scope_or_err.takeError());
+      LLDB_LOG_ERROR(GetLog(LLDBLog::Language), scope_or_err.takeError(),
+                     "Failed to retrieve scope: {0}");
       return false;
     }
 
@@ -1909,7 +1911,8 @@ bool CPlusPlusLanguage::HandleFrameFormatVariable(
   case FormatEntity::Entry::Type::FunctionBasename: {
     auto name_or_err = GetDemangledBasename(sc);
     if (!name_or_err) {
-      llvm::consumeError(name_or_err.takeError());
+      LLDB_LOG_ERROR(GetLog(LLDBLog::Language), name_or_err.takeError(),
+                     "Failed to retrieve basename: {0}");
       return false;
     }
 
@@ -1921,7 +1924,9 @@ bool CPlusPlusLanguage::HandleFrameFormatVariable(
   case FormatEntity::Entry::Type::FunctionTemplateArguments: {
     auto template_args_or_err = GetDemangledTemplateArguments(sc);
     if (!template_args_or_err) {
-      llvm::consumeError(template_args_or_err.takeError());
+      LLDB_LOG_ERROR(GetLog(LLDBLog::Language),
+                     template_args_or_err.takeError(),
+                     "Failed to retrieve template arguments: {0}");
       return false;
     }
 
@@ -1956,7 +1961,8 @@ bool CPlusPlusLanguage::HandleFrameFormatVariable(
   case FormatEntity::Entry::Type::FunctionReturnRight: {
     auto return_rhs_or_err = GetDemangledReturnTypeRHS(sc);
     if (!return_rhs_or_err) {
-      llvm::consumeError(return_rhs_or_err.takeError());
+      LLDB_LOG_ERROR(GetLog(LLDBLog::Language), return_rhs_or_err.takeError(),
+                     "Failed to retrieve RHS return type: {0}");
       return false;
     }
 
@@ -1967,7 +1973,8 @@ bool CPlusPlusLanguage::HandleFrameFormatVariable(
   case FormatEntity::Entry::Type::FunctionReturnLeft: {
     auto return_lhs_or_err = GetDemangledReturnTypeLHS(sc);
     if (!return_lhs_or_err) {
-      llvm::consumeError(return_lhs_or_err.takeError());
+      LLDB_LOG_ERROR(GetLog(LLDBLog::Language), return_lhs_or_err.takeError(),
+                     "Failed to retrieve LHS return type: {0}");
       return false;
     }
 
@@ -1978,7 +1985,8 @@ bool CPlusPlusLanguage::HandleFrameFormatVariable(
   case FormatEntity::Entry::Type::FunctionQualifiers: {
     auto quals_or_err = GetDemangledFunctionQualifiers(sc);
     if (!quals_or_err) {
-      llvm::consumeError(quals_or_err.takeError());
+      LLDB_LOG_ERROR(GetLog(LLDBLog::Language), quals_or_err.takeError(),
+                     "Failed to retrieve function qualifiers: {0}");
       return false;
     }
 
@@ -1989,7 +1997,8 @@ bool CPlusPlusLanguage::HandleFrameFormatVariable(
   case FormatEntity::Entry::Type::FunctionSuffix: {
     auto suffix_or_err = GetDemangledFunctionSuffix(sc);
     if (!suffix_or_err) {
-      llvm::consumeError(suffix_or_err.takeError());
+      LLDB_LOG_ERROR(GetLog(LLDBLog::Language), suffix_or_err.takeError(),
+                     "Failed to retrieve suffix: {0}");
       return false;
     }
 

>From 68d8d5a699a53097351e45a46854563bf85544c2 Mon Sep 17 00:00:00 2001
From: Charles Zablit <c_zablit at apple.com>
Date: Thu, 19 Jun 2025 12:27:44 +0100
Subject: [PATCH 4/5] improve error messages

---
 .../Language/CPlusPlus/CPlusPlusLanguage.cpp  | 66 ++++++++++++-------
 1 file changed, 44 insertions(+), 22 deletions(-)

diff --git a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
index 20ecac44eafd2..95cd2e8ea87c5 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
@@ -244,15 +244,20 @@ GetAndValidateInfo(const SymbolContext &sc) {
 
   auto demangled_name = mangled.GetDemangledName().GetStringRef();
   if (demangled_name.empty())
-    return llvm::createStringError("Function does not have a demangled name.");
+    return llvm::createStringError(
+        "Function '%s' does not have a demangled name.",
+        mangled.GetMangledName().AsCString(""));
 
   const std::optional<DemangledNameInfo> &info = mangled.GetDemangledInfo();
   if (!info)
-    return llvm::createStringError("Function does not have demangled info.");
+    return llvm::createStringError(
+        "Function '%s' does not have demangled info.", demangled_name.data());
 
   // Function without a basename is nonsense.
   if (!info->hasBasename())
-    return llvm::createStringError("Info do not have basename range.");
+    return llvm::createStringError(
+        "DemangledInfo for '%s does not have basename range.",
+        demangled_name.data());
 
   return std::make_pair(demangled_name, *info);
 }
@@ -278,7 +283,8 @@ GetDemangledTemplateArguments(const SymbolContext &sc) {
   auto [demangled_name, info] = *info_or_err;
 
   if (info.ArgumentsRange.first < info.BasenameRange.second)
-    return llvm::createStringError("Arguments in info are invalid.");
+    return llvm::createStringError("Arguments range for '%s' is invalid.",
+                                   demangled_name.data());
 
   return demangled_name.slice(info.BasenameRange.second,
                               info.ArgumentsRange.first);
@@ -293,7 +299,9 @@ GetDemangledReturnTypeLHS(const SymbolContext &sc) {
   auto [demangled_name, info] = *info_or_err;
 
   if (info.ScopeRange.first >= demangled_name.size())
-    return llvm::createStringError("Scope range is invalid.");
+    return llvm::createStringError(
+        "Scope range for '%s' LHS return type is invalid.",
+        demangled_name.data());
 
   return demangled_name.substr(0, info.ScopeRange.first);
 }
@@ -307,7 +315,8 @@ GetDemangledFunctionQualifiers(const SymbolContext &sc) {
   auto [demangled_name, info] = *info_or_err;
 
   if (info.QualifiersRange.second < info.QualifiersRange.first)
-    return llvm::createStringError("Qualifiers range is invalid.");
+    return llvm::createStringError("Qualifiers range for '%s' is invalid.",
+                                   demangled_name.data());
 
   return demangled_name.slice(info.QualifiersRange.first,
                               info.QualifiersRange.second);
@@ -321,8 +330,12 @@ GetDemangledReturnTypeRHS(const SymbolContext &sc) {
 
   auto [demangled_name, info] = *info_or_err;
 
-  if (info.QualifiersRange.first < info.ArgumentsRange.second)
-    return llvm::createStringError("Qualifiers range is invalid.");
+  if (info.QualifiersRange.first <
+      info.ArgumentsRange.second) // TODO: Replace with .hasArgumentsRange()
+                                  // once #144549 lands.
+    return llvm::createStringError(
+        "Qualifiers range for '%s' RHS return type  is invalid.",
+        demangled_name.data());
 
   return demangled_name.slice(info.ArgumentsRange.second,
                               info.QualifiersRange.first);
@@ -337,7 +350,8 @@ GetDemangledScope(const SymbolContext &sc) {
   auto [demangled_name, info] = *info_or_err;
 
   if (info.ScopeRange.second < info.ScopeRange.first)
-    return llvm::createStringError("Info do not have basename range.");
+    return llvm::createStringError("Scope range for '%s' is invalid.",
+                                   demangled_name.data());
 
   return demangled_name.slice(info.ScopeRange.first, info.ScopeRange.second);
 }
@@ -360,8 +374,9 @@ static bool PrintDemangledArgumentList(Stream &s, const SymbolContext &sc) {
 
   auto info_or_err = GetAndValidateInfo(sc);
   if (!info_or_err) {
-    LLDB_LOG_ERROR(GetLog(LLDBLog::Language), info_or_err.takeError(),
-                   "Failed to retrieve demangled info: {0}");
+    LLDB_LOG_ERROR(
+        GetLog(LLDBLog::Language), info_or_err.takeError(),
+        "Failed to handle ${function.basename} frame-format variable: {0}");
     return false;
   }
   auto [demangled_name, info] = *info_or_err;
@@ -1898,8 +1913,9 @@ bool CPlusPlusLanguage::HandleFrameFormatVariable(
   case FormatEntity::Entry::Type::FunctionScope: {
     auto scope_or_err = GetDemangledScope(sc);
     if (!scope_or_err) {
-      LLDB_LOG_ERROR(GetLog(LLDBLog::Language), scope_or_err.takeError(),
-                     "Failed to retrieve scope: {0}");
+      LLDB_LOG_ERROR(
+          GetLog(LLDBLog::Language), scope_or_err.takeError(),
+          "Failed to handle ${function.scope} frame-format variable: {0}");
       return false;
     }
 
@@ -1911,8 +1927,9 @@ bool CPlusPlusLanguage::HandleFrameFormatVariable(
   case FormatEntity::Entry::Type::FunctionBasename: {
     auto name_or_err = GetDemangledBasename(sc);
     if (!name_or_err) {
-      LLDB_LOG_ERROR(GetLog(LLDBLog::Language), name_or_err.takeError(),
-                     "Failed to retrieve basename: {0}");
+      LLDB_LOG_ERROR(
+          GetLog(LLDBLog::Language), name_or_err.takeError(),
+          "Failed to handle ${function.basename} frame-format variable: {0}");
       return false;
     }
 
@@ -1926,7 +1943,8 @@ bool CPlusPlusLanguage::HandleFrameFormatVariable(
     if (!template_args_or_err) {
       LLDB_LOG_ERROR(GetLog(LLDBLog::Language),
                      template_args_or_err.takeError(),
-                     "Failed to retrieve template arguments: {0}");
+                     "Failed to handle ${function.template-arguments} "
+                     "frame-format variable: {0}");
       return false;
     }
 
@@ -1962,7 +1980,8 @@ bool CPlusPlusLanguage::HandleFrameFormatVariable(
     auto return_rhs_or_err = GetDemangledReturnTypeRHS(sc);
     if (!return_rhs_or_err) {
       LLDB_LOG_ERROR(GetLog(LLDBLog::Language), return_rhs_or_err.takeError(),
-                     "Failed to retrieve RHS return type: {0}");
+                     "Failed to handle ${function.return-right} frame-format "
+                     "variable: {0}");
       return false;
     }
 
@@ -1974,7 +1993,8 @@ bool CPlusPlusLanguage::HandleFrameFormatVariable(
     auto return_lhs_or_err = GetDemangledReturnTypeLHS(sc);
     if (!return_lhs_or_err) {
       LLDB_LOG_ERROR(GetLog(LLDBLog::Language), return_lhs_or_err.takeError(),
-                     "Failed to retrieve LHS return type: {0}");
+                     "Failed to handle ${function.return-left} frame-format "
+                     "variable: {0}");
       return false;
     }
 
@@ -1985,8 +2005,9 @@ bool CPlusPlusLanguage::HandleFrameFormatVariable(
   case FormatEntity::Entry::Type::FunctionQualifiers: {
     auto quals_or_err = GetDemangledFunctionQualifiers(sc);
     if (!quals_or_err) {
-      LLDB_LOG_ERROR(GetLog(LLDBLog::Language), quals_or_err.takeError(),
-                     "Failed to retrieve function qualifiers: {0}");
+      LLDB_LOG_ERROR(
+          GetLog(LLDBLog::Language), quals_or_err.takeError(),
+          "Failed to handle ${function.qualifiers} frame-format variable: {0}");
       return false;
     }
 
@@ -1997,8 +2018,9 @@ bool CPlusPlusLanguage::HandleFrameFormatVariable(
   case FormatEntity::Entry::Type::FunctionSuffix: {
     auto suffix_or_err = GetDemangledFunctionSuffix(sc);
     if (!suffix_or_err) {
-      LLDB_LOG_ERROR(GetLog(LLDBLog::Language), suffix_or_err.takeError(),
-                     "Failed to retrieve suffix: {0}");
+      LLDB_LOG_ERROR(
+          GetLog(LLDBLog::Language), suffix_or_err.takeError(),
+          "Failed to handle ${function.suffix} frame-format variable: {0}");
       return false;
     }
 

>From 6d8e8c077729a7c540ed6b2090f8b08c7a0e56d9 Mon Sep 17 00:00:00 2001
From: Charles Zablit <c_zablit at apple.com>
Date: Thu, 19 Jun 2025 14:54:04 +0100
Subject: [PATCH 5/5] switch to `has` methods

---
 .../source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
index 95cd2e8ea87c5..0a816ef8eeaa7 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
@@ -314,7 +314,7 @@ GetDemangledFunctionQualifiers(const SymbolContext &sc) {
 
   auto [demangled_name, info] = *info_or_err;
 
-  if (info.QualifiersRange.second < info.QualifiersRange.first)
+  if (!info.hasQualifiers())
     return llvm::createStringError("Qualifiers range for '%s' is invalid.",
                                    demangled_name.data());
 
@@ -349,7 +349,7 @@ GetDemangledScope(const SymbolContext &sc) {
 
   auto [demangled_name, info] = *info_or_err;
 
-  if (info.ScopeRange.second < info.ScopeRange.first)
+  if (!info.hasScope())
     return llvm::createStringError("Scope range for '%s' is invalid.",
                                    demangled_name.data());
 
@@ -381,7 +381,7 @@ static bool PrintDemangledArgumentList(Stream &s, const SymbolContext &sc) {
   }
   auto [demangled_name, info] = *info_or_err;
 
-  if (info.ArgumentsRange.second < info.ArgumentsRange.first)
+  if (!info.hasArguments())
     return false;
 
   s << demangled_name.slice(info.ArgumentsRange.first,



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