[LLDB][NativePDB] Add local variables with no location info.

[zequanwu]

Summary

If we don't add local variables with no location info, when trying to print it,
lldb won't find it in the its parent DeclContext, which makes lldb to spend more
time to search all the way up in DeclContext hierarchy until found same name
variable or failed. Dwarf plugin also add local vars even if they don't have
location info.

lldb/source/Plugins/SymbolFile/NativePDB/PdbUtil.h

SegmentOffsetLength(uint16_t s, uint32_t o, uint32_t l)
       : so(s, o), length(l) {}
   SegmentOffset so;
   uint32_t length = 0;
 };
 
 struct VariableInfo {
   llvm::StringRef name;
   llvm::codeview::TypeIndex type;
-  llvm::Optional<DWARFExpressionList> location;
+  DWARFExpressionList location;
   bool is_param;
 };
 
 llvm::pdb::PDB_SymType CVSymToPDBSym(llvm::codeview::SymbolKind kind);
 llvm::pdb::PDB_SymType CVTypeToPDBType(llvm::codeview::TypeLeafKind kind);
 
 bool SymbolHasAddress(const llvm::codeview::CVSymbol &sym);
 bool SymbolIsCode(const llvm::codeview::CVSymbol &sym);

lldb/source/Plugins/SymbolFile/NativePDB/PdbUtil.cpp

while (!finished) {
       default:
         finished = true;
         break;
       }
       loc_specifier_id = PdbCompilandSymId(
           loc_specifier_id.modi,
           loc_specifier_id.offset + loc_specifier_cvs.RecordData.size());
     }
-    result.location = DWARFExpressionList();
     for (const auto &entry : location_map) {
       DWARFExpression dwarf_expr =
           entry.data.is_dwarf ? entry.data.expr
                               : MakeEnregisteredLocationExpressionForComposite(
                                     entry.data.offset_to_location,
                                     offset_to_size, type_size, module);
 
-      result.location->AddExpression(entry.GetRangeBase(), entry.GetRangeEnd(),
+      result.location.AddExpression(entry.GetRangeBase(), entry.GetRangeEnd(),
                                      dwarf_expr);
     }
     return result;
   }
   llvm_unreachable("Symbol is not a local variable!");
   return result;
 }
 

lldb/source/Plugins/SymbolFile/NativePDB/SymbolFileNativePDB.cpp

VariableSP SymbolFileNativePDB::CreateLocalVariable(PdbCompilandSymId scope_id,
   Block *func_block = █
   while (func_block->GetParent()) {
     func_block = func_block->GetParent();
   }
   Address addr;
   func_block->GetStartAddress(addr);
   VariableInfo var_info =
       GetVariableLocationInfo(*m_index, var_id, *func_block, module);
-  if (!var_info.location || var_info.location->GetSize() == 0)
-    return nullptr;
   Function *func = func_block->CalculateSymbolContextFunction();
   if (!func)
-    return VariableSP();
-  var_info.location->SetFuncFileAddress(
+    return nullptr;
+  // Use empty dwarf expr if optimized away so that it won't be filtered out
+  // when lookuping local variables in this scope.
+  if (!var_info.location.IsValid())
+    var_info.location = DWARFExpressionList(module, DWARFExpression(), nullptr);
+  var_info.location.SetFuncFileAddress(
       func->GetAddressRange().GetBaseAddress().GetFileAddress());
   CompilandIndexItem *cii = m_index->compilands().GetCompiland(var_id.modi);
   CompUnitSP comp_unit_sp = GetOrCreateCompileUnit(*cii);
   TypeSP type_sp = GetOrCreateType(var_info.type);
   if (!type_sp)
     return nullptr;
   std::string name = var_info.name.str();
   Declaration decl;
   SymbolFileTypeSP sftype =
       std::make_shared<SymbolFileType>(*this, type_sp->GetID());
 
   is_param |= var_info.is_param;
   ValueType var_scope =
       is_param ? eValueTypeVariableArgument : eValueTypeVariableLocal;
   bool external = false;
   bool artificial = false;
   bool location_is_constant_data = false;
   bool static_member = false;
   Variable::RangeList scope_ranges;
   VariableSP var_sp = std::make_shared<Variable>(
       toOpaqueUid(var_id), name.c_str(), name.c_str(), sftype, var_scope,
-      &block, scope_ranges, &decl, *var_info.location, external, artificial,
+      &block, scope_ranges, &decl, var_info.location, external, artificial,
       location_is_constant_data, static_member);
   if (!is_param)
     m_ast->GetOrCreateVariableDecl(scope_id, var_id);
-
   m_local_variables[toOpaqueUid(var_id)] = var_sp;
   return var_sp;
 }
 
 VariableSP SymbolFileNativePDB::GetOrCreateLocalVariable(
     PdbCompilandSymId scope_id, PdbCompilandSymId var_id, bool is_param) {
   auto iter = m_local_variables.find(toOpaqueUid(var_id));
   if (iter != m_local_variables.end())

lldb/test/Shell/SymbolFile/NativePDB/inline_sites.test

 
 # CEHCK-LABEL: (lldb) image lookup -a 0x140001004 -v
 # CHECK:       Summary: {{.*}}`main + 4 [inlined] Namespace1::foo at a.h:5
 # CHECK-NEXT:           {{.*}}`main + 4 at a.cpp:3
 # CHECK:       Function: id = {{.*}}, name = "main", range = [0x0000000140001000-0x0000000140001046)
 # CHECK:         Blocks: id = {{.*}}, range = [0x140001000-0x140001046)
 # CHECK-NEXT:            id = {{.*}}, ranges = [0x140001004-0x140001039)[0x14000103f-0x140001046), name = "Namespace1::foo", decl = a.h:4
 # CHECK:       LineEntry: [0x0000000140001004-0x000000014000100c): /tmp/a.h:5
+# CHECK-NEXT:  Variable: id = {{.*}}, name = "x", type = "int", valid ranges = <block>, location = <empty>, decl =
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "foo_local", type = "int", valid ranges = <block>, location = [0x0000000140001004, 0x0000000140001039) -> DW_OP_breg7 RSP+44
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "argc", type = "int", valid ranges = <block>, location = [0x0000000140001000, 0x000000014000102d) -> DW_OP_reg26 XMM9
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "argv", type = "char **", valid ranges = <block>, location = [0x0000000140001000, 0x0000000140001045) -> DW_OP_reg3 RBX
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "main_local", type = "int", valid ranges = <block>, location = [0x0000000140001004, 0x0000000140001046) -> DW_OP_breg7 RSP+48
 
 # CEHCK-LABEL: (lldb) image lookup -a 0x140001010 -v
 # CHECK:       Summary: {{.*}}`main + 16 [inlined] Namespace1::foo + 12 at a.h:7
 # CHECK-NEXT:           {{.*}}`main + 4 at a.cpp:3
 # CHECK:       Function: id = {{.*}}, name = "main", range = [0x0000000140001000-0x0000000140001046)
 # CHECK:         Blocks: id = {{.*}}, range = [0x140001000-0x140001046)
 # CHECK-NEXT:            id = {{.*}}, ranges = [0x140001004-0x140001039)[0x14000103f-0x140001046), name = "Namespace1::foo", decl = a.h:4
 # CHECK:       LineEntry: [0x0000000140001010-0x0000000140001018): /tmp/a.h:7
+# CHECK-NEXT:  Variable: id = {{.*}}, name = "x", type = "int", valid ranges = <block>, location = <empty>, decl =
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "foo_local", type = "int", valid ranges = <block>, location = [0x0000000140001004, 0x0000000140001039) -> DW_OP_breg7 RSP+44
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "argc", type = "int", valid ranges = <block>, location = [0x0000000140001000, 0x000000014000102d) -> DW_OP_reg26 XMM9
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "argv", type = "char **", valid ranges = <block>, location = [0x0000000140001000, 0x0000000140001045) -> DW_OP_reg3 RBX
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "main_local", type = "int", valid ranges = <block>, location = [0x0000000140001004, 0x0000000140001046) -> DW_OP_breg7 RSP+48
 
 # CEHCK-LABEL: (lldb) image lookup -a 0x14000101c -v
 # CHECK:       Summary: {{.*}}`main + 28 [inlined] Class1::bar at b.h:5
 # CHECK-NEXT:           {{.*}}`main + 28 [inlined] Namespace1::foo + 24 at a.h:9
 # CHECK-NEXT:           {{.*}}`main + 4 at a.cpp:3
 # CHECK:       Function: id = {{.*}}, name = "main", range = [0x0000000140001000-0x0000000140001046)
 # CHECK:         Blocks: id = {{.*}}, range = [0x140001000-0x140001046)
 # CHECK-NEXT:            id = {{.*}}, ranges = [0x140001004-0x140001039)[0x14000103f-0x140001046), name = "Namespace1::foo", decl = a.h:4
 # CHECK-NEXT:            id = {{.*}}, range = [0x14000101c-0x140001039), name = "Class1::bar", decl = b.h:4
 # CHECK:       LineEntry: [0x000000014000101c-0x0000000140001022): /tmp/b.h:5
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "x", type = "int", valid ranges = <block>, location = [0x000000014000101c, 0x000000014000101e) -> DW_OP_reg24 XMM7
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "bar_local", type = "int", valid ranges = <block>, location = [0x000000014000101c, 0x0000000140001039) -> DW_OP_breg7 RSP+52
+# CHECK-NEXT:  Variable: id = {{.*}}, name = "x", type = "int", valid ranges = <block>, location = <empty>, decl =
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "foo_local", type = "int", valid ranges = <block>, location = [0x0000000140001004, 0x0000000140001039) -> DW_OP_breg7 RSP+44
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "argc", type = "int", valid ranges = <block>, location = [0x0000000140001000, 0x000000014000102d) -> DW_OP_reg26 XMM9
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "argv", type = "char **", valid ranges = <block>, location = [0x0000000140001000, 0x0000000140001045) -> DW_OP_reg3 RBX
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "main_local", type = "int", valid ranges = <block>, location = [0x0000000140001004, 0x0000000140001046) -> DW_OP_breg7 RSP+48
 
 # CEHCK-LABEL: (lldb) image lookup -a 0x14000102a -v
 # CHECK:       Summary: {{.*}}`main + 42 [inlined] Namespace2::Class2::func at c.h:5
 # CHECK-NEXT:           {{.*}}`main + 42 [inlined] Class1::bar + 14 at b.h:7
 # CHECK-NEXT:           {{.*}}`main + 28 [inlined] Namespace1::foo + 24 at a.h:9
 # CHECK-NEXT:           {{.*}}`main + 4 at a.cpp:3
 # CHECK:       Function: id = {{.*}}, name = "main", range = [0x0000000140001000-0x0000000140001046)
 # CHECK:         Blocks: id = {{.*}}, range = [0x140001000-0x140001046)
 # CHECK-NEXT:            id = {{.*}}, ranges = [0x140001004-0x140001039)[0x14000103f-0x140001046), name = "Namespace1::foo", decl = a.h:4
 # CHECK-NEXT:            id = {{.*}}, range = [0x14000101c-0x140001039), name = "Class1::bar", decl = b.h:4
 # CHECK-NEXT:            id = {{.*}}, range = [0x14000102a-0x140001039), name = "Namespace2::Class2::func", decl = c.h:4
 # CHECK:       LineEntry: [0x000000014000102a-0x0000000140001031): /tmp/c.h:5
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "x", type = "int", valid ranges = <block>, location = [0x000000014000102a, 0x0000000140001039) -> DW_OP_reg24 XMM7
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "func_local", type = "int", valid ranges = <block>, location = [0x000000014000102a, 0x0000000140001039) -> DW_OP_breg7 RSP+48
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "bar_local", type = "int", valid ranges = <block>, location = [0x000000014000101c, 0x0000000140001039) -> DW_OP_breg7 RSP+52
+# CHECK-NEXT:  Variable: id = {{.*}}, name = "x", type = "int", valid ranges = <block>, location = <empty>, decl =
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "foo_local", type = "int", valid ranges = <block>, location = [0x0000000140001004, 0x0000000140001039) -> DW_OP_breg7 RSP+44
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "argc", type = "int", valid ranges = <block>, location = [0x0000000140001000, 0x000000014000102d) -> DW_OP_reg26 XMM9
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "argv", type = "char **", valid ranges = <block>, location = [0x0000000140001000, 0x0000000140001045) -> DW_OP_reg3 RBX
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "main_local", type = "int", valid ranges = <block>, location = [0x0000000140001004, 0x0000000140001046) -> DW_OP_breg7 RSP+48
 
 # CEHCK-LABEL: (lldb) image lookup -a 0x140001039 -v
 # CHECK:       Summary: {{.*}}`main + 57 at a.cpp:3
 # CHECK:       Function: id = {{.*}}, name = "main", range = [0x0000000140001000-0x0000000140001046)
 # CHECK:         Blocks: id = {{.*}}, range = [0x140001000-0x140001046)
 # CHECK:       LineEntry: [0x0000000140001039-0x000000014000103d): /tmp/a.cpp:3
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "argv", type = "char **", valid ranges = <block>, location = [0x0000000140001000, 0x0000000140001045) -> DW_OP_reg3 RBX
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "main_local", type = "int", valid ranges = <block>, location = [0x0000000140001004, 0x0000000140001046) -> DW_OP_breg7 RSP+48
 
 # CEHCK-LABEL: (lldb) image lookup -a 0x140001044 -v
 # CHECK:       Summary: {{.*}}`main + 68 [inlined] Namespace1::foo + 5 at a.h:8
 # CHECK-NEXT:           {{.*}}`main + 63 at a.cpp:3
 # CHECK:       Function: id = {{.*}}, name = "main", range = [0x0000000140001000-0x0000000140001046)
 # CHECK:         Blocks: id = {{.*}}, range = [0x140001000-0x140001046)
 # CHECK-NEXT:            id = {{.*}}, ranges = [0x140001004-0x140001039)[0x14000103f-0x140001046), name = "Namespace1::foo", decl = a.h:4
 # CHECK:       LineEntry: [0x0000000140001044-0x0000000140001046): /tmp/a.h:8
+# CHECK-NEXT:  Variable: id = {{.*}}, name = "x", type = "int", valid ranges = <block>, location = <empty>, decl =
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "foo_local", type = "int", valid ranges = <block>, location = [0x0000000140001044, 0x0000000140001046) -> DW_OP_breg7 RSP+44
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "argc", type = "int", valid ranges = <block>, location = [0x0000000140001044, 0x0000000140001045) -> DW_OP_reg26 XMM9
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "argv", type = "char **", valid ranges = <block>, location = [0x0000000140001000, 0x0000000140001045) -> DW_OP_reg3 RBX
 # CHECK-NEXT:  Variable: id = {{.*}}, name = "main_local", type = "int", valid ranges = <block>, location = [0x0000000140001004, 0x0000000140001046) -> DW_OP_breg7 RSP+48
 
 # CHECK-LABEL: (lldb) target modules dump ast
 # CHECK-NEXT:  Dumping clang ast for 1 modules.
 # CHECK-NEXT:  TranslationUnitDecl {{.*}} <undeserialized declarations>