[LLDB][NativePDB] Create functions with mangled name (#149701)

Before, functions created using the NativePDB plugin would not know
about their mangled name. This showed when printing a stacktrace. There,
only the function name was shown. For
https://github.com/llvm/llvm-project/issues/143149, the mangled function
name is required to separate different parts.

This PR adds that name if available.

The Clang AST nodes also take in a mangled name, which was previously
unset. I don't think this unblocks anything further, because Clang can
mangle the function anyway.

1 files changed, 28 insertions, 1 deletions

diff --git a/lldb/source/Plugins/SymbolFile/NativePDB/SymbolFileNativePDB.cpp b/lldb/source/Plugins/SymbolFile/NativePDB/SymbolFileNativePDB.cpp
index 8b3d775afc16..fcb2e8d0dc99 100644
--- a/lldb/source/Plugins/SymbolFile/NativePDB/SymbolFileNativePDB.cpp
+++ b/lldb/source/Plugins/SymbolFile/NativePDB/SymbolFileNativePDB.cpp
@@ -501,7 +501,9 @@ lldb::FunctionSP SymbolFileNativePDB::CreateFunction(PdbCompilandSymId func_id,
     return nullptr;
 
   PdbTypeSymId sig_id(proc.FunctionType, false);
-  Mangled mangled(proc.Name);
+  std::optional<llvm::StringRef> mangled_opt =
+      FindMangledSymbol(SegmentOffset(proc.Segment, proc.CodeOffset));
+  Mangled mangled(mangled_opt.value_or(proc.Name));
   FunctionSP func_sp = std::make_shared<Function>(
       &comp_unit, toOpaqueUid(func_id), toOpaqueUid(sig_id), mangled,
       func_type.get(), func_addr,
@@ -2662,6 +2664,31 @@ SymbolFileNativePDB::GetContextForType(TypeIndex ti) {
   return ctx;
 }
 
+std::optional<llvm::StringRef>
+SymbolFileNativePDB::FindMangledFunctionName(PdbCompilandSymId func_id) {
+  const CompilandIndexItem *cci =
+      m_index->compilands().GetCompiland(func_id.modi);
+  if (!cci)
+    return std::nullopt;
+
+  CVSymbol sym_record = cci->m_debug_stream.readSymbolAtOffset(func_id.offset);
+  if (sym_record.kind() != S_LPROC32 && sym_record.kind() != S_GPROC32)
+    return std::nullopt;
+
+  ProcSym proc(static_cast<SymbolRecordKind>(sym_record.kind()));
+  cantFail(SymbolDeserializer::deserializeAs<ProcSym>(sym_record, proc));
+  return FindMangledSymbol(SegmentOffset(proc.Segment, proc.CodeOffset));
+}
+
+std::optional<llvm::StringRef>
+SymbolFileNativePDB::FindMangledSymbol(SegmentOffset so) {
+  auto symbol = m_index->publics().findByAddress(m_index->symrecords(),
+                                                 so.segment, so.offset);
+  if (!symbol)
+    return std::nullopt;
+  return symbol->first.Name;
+}
+
 void SymbolFileNativePDB::CacheUdtDeclarations() {
   for (CVType cvt : m_index->ipi().typeArray()) {
     switch (cvt.kind()) {