[lldb] (Begin to) support discontinuous lldb_private::Functions (#115730)

labath · web-flow · commit 2a3c08f620fc · 2024-11-12T09:34:53.000+01:00
This is the beginning of a different, more fundamental approach to
handling. This PR tries to tries to minimize functional changes. It only
makes sure that we store the true set of ranges inside the function
object, so that subsequent patches can make use of it.
diff --git a/lldb/include/lldb/Symbol/Function.h b/lldb/include/lldb/Symbol/Function.h
@@ -428,7 +428,7 @@ class Function : public UserID, public SymbolContextScope {
   ///     The section offset based address for this function.
   Function(CompileUnit *comp_unit, lldb::user_id_t func_uid,
            lldb::user_id_t func_type_uid, const Mangled &mangled,
-           Type *func_type, const AddressRange &range);
+           Type *func_type, AddressRanges ranges);
 
   /// Destructor.
   ~Function() override;
@@ -649,8 +649,12 @@ class Function : public UserID, public SymbolContextScope {
   /// All lexical blocks contained in this function.
   Block m_block;
 
+  /// List of address ranges belonging to the function.
+  AddressRanges m_ranges;
+
   /// The function address range that covers the widest range needed to contain
-  /// all blocks
+  /// all blocks. DEPRECATED: do not use this field in new code as the range may
+  /// include addresses belonging to other functions.
   AddressRange m_range;
 
   /// The frame base expression for variables that are relative to the frame
diff --git a/lldb/source/Plugins/SymbolFile/Breakpad/SymbolFileBreakpad.cpp b/lldb/source/Plugins/SymbolFile/Breakpad/SymbolFileBreakpad.cpp
@@ -255,7 +255,7 @@ FunctionSP SymbolFileBreakpad::GetOrCreateFunction(CompileUnit &comp_unit) {
           section_sp, address - section_sp->GetFileAddress(), record->Size);
       // Use the CU's id because every CU has only one function inside.
       func_sp = std::make_shared<Function>(&comp_unit, id, 0, func_name,
-                                           nullptr, func_range);
+                                           nullptr, AddressRanges{func_range});
       comp_unit.AddFunction(func_sp);
     }
   }
diff --git a/lldb/source/Plugins/SymbolFile/CTF/SymbolFileCTF.cpp b/lldb/source/Plugins/SymbolFile/CTF/SymbolFileCTF.cpp
@@ -829,7 +829,7 @@ size_t SymbolFileCTF::ParseFunctions(CompileUnit &cu) {
       lldb::user_id_t func_uid = m_functions.size();
       FunctionSP function_sp = std::make_shared<Function>(
           &cu, func_uid, function_type_uid, symbol->GetMangled(), type_sp.get(),
-          func_range);
+          AddressRanges{func_range});
       m_functions.emplace_back(function_sp);
       cu.AddFunction(function_sp);
     }
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParser.h b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParser.h
@@ -42,7 +42,7 @@ class DWARFASTParser {
 
   virtual Function *ParseFunctionFromDWARF(CompileUnit &comp_unit,
                                            const DWARFDIE &die,
-                                           const AddressRange &range) = 0;
+                                           AddressRanges ranges) = 0;
 
   virtual bool CompleteTypeFromDWARF(const DWARFDIE &die, Type *type,
                                      const CompilerType &compiler_type) = 0;
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
@@ -2340,12 +2340,9 @@ DWARFASTParserClang::ConstructDemangledNameFromDWARF(const DWARFDIE &die) {
   return ConstString(sstr.GetString());
 }
 
-Function *
-DWARFASTParserClang::ParseFunctionFromDWARF(CompileUnit &comp_unit,
-                                            const DWARFDIE &die,
-                                            const AddressRange &func_range) {
-  assert(func_range.GetBaseAddress().IsValid());
-  DWARFRangeList func_ranges;
+Function *DWARFASTParserClang::ParseFunctionFromDWARF(
+    CompileUnit &comp_unit, const DWARFDIE &die, AddressRanges func_ranges) {
+  DWARFRangeList unused_func_ranges;
   const char *name = nullptr;
   const char *mangled = nullptr;
   std::optional<int> decl_file;
@@ -2361,9 +2358,9 @@ DWARFASTParserClang::ParseFunctionFromDWARF(CompileUnit &comp_unit,
   if (tag != DW_TAG_subprogram)
     return nullptr;
 
-  if (die.GetDIENamesAndRanges(name, mangled, func_ranges, decl_file, decl_line,
-                               decl_column, call_file, call_line, call_column,
-                               &frame_base)) {
+  if (die.GetDIENamesAndRanges(name, mangled, unused_func_ranges, decl_file,
+                               decl_line, decl_column, call_file, call_line,
+                               call_column, &frame_base)) {
     Mangled func_name;
     if (mangled)
       func_name.SetValue(ConstString(mangled));
@@ -2395,11 +2392,10 @@ DWARFASTParserClang::ParseFunctionFromDWARF(CompileUnit &comp_unit,
     assert(func_type == nullptr || func_type != DIE_IS_BEING_PARSED);
 
     const user_id_t func_user_id = die.GetID();
-    func_sp =
-        std::make_shared<Function>(&comp_unit,
-                                   func_user_id, // UserID is the DIE offset
-                                   func_user_id, func_name, func_type,
-                                   func_range); // first address range
+    func_sp = std::make_shared<Function>(
+        &comp_unit,
+        func_user_id, // UserID is the DIE offset
+        func_user_id, func_name, func_type, std::move(func_ranges));
 
     if (func_sp.get() != nullptr) {
       if (frame_base.IsValid())
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h
@@ -59,7 +59,7 @@ class DWARFASTParserClang : public lldb_private::plugin::dwarf::DWARFASTParser {
   lldb_private::Function *
   ParseFunctionFromDWARF(lldb_private::CompileUnit &comp_unit,
                          const lldb_private::plugin::dwarf::DWARFDIE &die,
-                         const lldb_private::AddressRange &func_range) override;
+                         lldb_private::AddressRanges func_ranges) override;
 
   bool CompleteTypeFromDWARF(
       const lldb_private::plugin::dwarf::DWARFDIE &die,
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
@@ -918,32 +918,20 @@ Function *SymbolFileDWARF::ParseFunction(CompileUnit &comp_unit,
   if (!dwarf_ast)
     return nullptr;
 
-  DWARFRangeList ranges = die.GetDIE()->GetAttributeAddressRanges(
-      die.GetCU(), /*check_hi_lo_pc=*/true);
-  if (ranges.IsEmpty())
-    return nullptr;
-
-  // Union of all ranges in the function DIE (if the function is
-  // discontiguous)
-  lldb::addr_t lowest_func_addr = ranges.GetMinRangeBase(0);
-  lldb::addr_t highest_func_addr = ranges.GetMaxRangeEnd(0);
-  if (lowest_func_addr == LLDB_INVALID_ADDRESS ||
-      lowest_func_addr >= highest_func_addr ||
-      lowest_func_addr < m_first_code_address)
-    return nullptr;
-
+  AddressRanges ranges;
   ModuleSP module_sp(die.GetModule());
-  AddressRange func_range;
-  func_range.GetBaseAddress().ResolveAddressUsingFileSections(
-      lowest_func_addr, module_sp->GetSectionList());
-  if (!func_range.GetBaseAddress().IsValid())
-    return nullptr;
-
-  func_range.SetByteSize(highest_func_addr - lowest_func_addr);
-  if (!FixupAddress(func_range.GetBaseAddress()))
+  for (const auto &range : die.GetDIE()->GetAttributeAddressRanges(
+           die.GetCU(), /*check_hi_lo_pc=*/true)) {
+    if (range.base < m_first_code_address)
+      continue;
+    if (Address base_addr(range.base, module_sp->GetSectionList());
+        base_addr.IsValid() && FixupAddress(base_addr))
+      ranges.emplace_back(std::move(base_addr), range.size);
+  }
+  if (ranges.empty())
     return nullptr;
 
-  return dwarf_ast->ParseFunctionFromDWARF(comp_unit, die, func_range);
+  return dwarf_ast->ParseFunctionFromDWARF(comp_unit, die, std::move(ranges));
 }
 
 ConstString
diff --git a/lldb/source/Plugins/SymbolFile/NativePDB/SymbolFileNativePDB.cpp b/lldb/source/Plugins/SymbolFile/NativePDB/SymbolFileNativePDB.cpp
@@ -504,7 +504,7 @@ lldb::FunctionSP SymbolFileNativePDB::CreateFunction(PdbCompilandSymId func_id,
   Mangled mangled(proc.Name);
   FunctionSP func_sp = std::make_shared<Function>(
       &comp_unit, toOpaqueUid(func_id), toOpaqueUid(sig_id), mangled,
-      func_type.get(), func_range);
+      func_type.get(), AddressRanges{func_range});
 
   comp_unit.AddFunction(func_sp);
 
diff --git a/lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp b/lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp
@@ -310,9 +310,9 @@ SymbolFilePDB::ParseCompileUnitFunctionForPDBFunc(const PDBSymbolFunc &pdb_func,
 
   Mangled mangled = GetMangledForPDBFunc(pdb_func);
 
-  FunctionSP func_sp =
-      std::make_shared<Function>(&comp_unit, pdb_func.getSymIndexId(),
-                                 func_type_uid, mangled, func_type, func_range);
+  FunctionSP func_sp = std::make_shared<Function>(
+      &comp_unit, pdb_func.getSymIndexId(), func_type_uid, mangled, func_type,
+      AddressRanges{func_range});
 
   comp_unit.AddFunction(func_sp);
 
diff --git a/lldb/source/Plugins/SymbolFile/Symtab/SymbolFileSymtab.cpp b/lldb/source/Plugins/SymbolFile/Symtab/SymbolFileSymtab.cpp
@@ -186,7 +186,7 @@ size_t SymbolFileSymtab::ParseFunctions(CompileUnit &comp_unit) {
                                                // for this function
                              curr_symbol->GetMangled(), // Linker/mangled name
                              nullptr, // no return type for a code symbol...
-                             func_range)); // first address range
+                             AddressRanges{func_range}));
 
             if (func_sp.get() != nullptr) {
               comp_unit.AddFunction(func_sp);
diff --git a/lldb/source/Symbol/Function.cpp b/lldb/source/Symbol/Function.cpp
@@ -254,12 +254,32 @@ Function *IndirectCallEdge::GetCallee(ModuleList &images,
 
 /// @}
 
+AddressRange CollapseRanges(llvm::ArrayRef<AddressRange> ranges) {
+  if (ranges.empty())
+    return AddressRange();
+  if (ranges.size() == 1)
+    return ranges[0];
+
+  Address lowest_addr = ranges[0].GetBaseAddress();
+  addr_t highest_addr = lowest_addr.GetFileAddress() + ranges[0].GetByteSize();
+  for (const AddressRange &range : ranges.drop_front()) {
+    Address range_begin = range.GetBaseAddress();
+    addr_t range_end = range_begin.GetFileAddress() + range.GetByteSize();
+    if (range_begin.GetFileAddress() < lowest_addr.GetFileAddress())
+      lowest_addr = range_begin;
+    if (range_end > highest_addr)
+      highest_addr = range_end;
+  }
+  return AddressRange(lowest_addr, highest_addr - lowest_addr.GetFileAddress());
+}
+
 //
 Function::Function(CompileUnit *comp_unit, lldb::user_id_t func_uid,
                    lldb::user_id_t type_uid, const Mangled &mangled, Type *type,
-                   const AddressRange &range)
+                   AddressRanges ranges)
     : UserID(func_uid), m_comp_unit(comp_unit), m_type_uid(type_uid),
-      m_type(type), m_mangled(mangled), m_block(func_uid), m_range(range),
+      m_type(type), m_mangled(mangled), m_block(func_uid),
+      m_ranges(std::move(ranges)), m_range(CollapseRanges(m_ranges)),
       m_frame_base(), m_flags(), m_prologue_byte_size(0) {
   m_block.SetParentScope(this);
   assert(comp_unit != nullptr);
@@ -406,14 +426,13 @@ void Function::GetDescription(Stream *s, lldb::DescriptionLevel level,
     llvm::interleaveComma(decl_context, *s, [&](auto &ctx) { ctx.Dump(*s); });
     *s << "}";
   }
-  *s << ", range = ";
-  Address::DumpStyle fallback_style;
-  if (level == eDescriptionLevelVerbose)
-    fallback_style = Address::DumpStyleModuleWithFileAddress;
-  else
-    fallback_style = Address::DumpStyleFileAddress;
-  GetAddressRange().Dump(s, target, Address::DumpStyleLoadAddress,
-                         fallback_style);
+  *s << ", range" << (m_ranges.size() > 1 ? "s" : "") << " = ";
+  Address::DumpStyle fallback_style =
+      level == eDescriptionLevelVerbose
+          ? Address::DumpStyleModuleWithFileAddress
+          : Address::DumpStyleFileAddress;
+  for (const AddressRange &range : m_ranges)
+    range.Dump(s, target, Address::DumpStyleLoadAddress, fallback_style);
 }
 
 void Function::Dump(Stream *s, bool show_context) const {
diff --git a/lldb/test/Shell/SymbolFile/DWARF/x86/discontinuous-function.s b/lldb/test/Shell/SymbolFile/DWARF/x86/discontinuous-function.s

Original file line number	Diff line number	Diff line change
`@@ -255,7 +255,7 @@ FunctionSP SymbolFileBreakpad::GetOrCreateFunction(CompileUnit &comp_unit) {`
`255`	`255`	`section_sp, address - section_sp->GetFileAddress(), record->Size);`
`256`	`256`	`// Use the CU's id because every CU has only one function inside.`
`257`	`257`	`func_sp = std::make_shared<Function>(&comp_unit, id, 0, func_name,`
`258`		`- nullptr, func_range);`
	`258`	`+ nullptr, AddressRanges{func_range});`
`259`	`259`	`comp_unit.AddFunction(func_sp);`
`260`	`260`	`}`
`261`	`261`	`}`
Original file line number	Diff line number	Diff line change
`@@ -829,7 +829,7 @@ size_t SymbolFileCTF::ParseFunctions(CompileUnit &cu) {`
`829`	`829`	`lldb::user_id_t func_uid = m_functions.size();`
`830`	`830`	`FunctionSP function_sp = std::make_shared<Function>(`
`831`	`831`	`&cu, func_uid, function_type_uid, symbol->GetMangled(), type_sp.get(),`
`832`		`- func_range);`
	`832`	`+ AddressRanges{func_range});`
`833`	`833`	`m_functions.emplace_back(function_sp);`
`834`	`834`	`cu.AddFunction(function_sp);`
`835`	`835`	`}`