[lldb] Turn LineEntry into a class and make AddressRange member optional

This patch relaxes the LineEntry validity from requiring a valid
AddressRange to turning the LineEntry `struct` into a `class` and make
the AddressRange member a private optional.

This addresses a problem for when LineEntry are created from the SB API,
because there is no way of adding an address range to an SBLineEntry,
it's always invalid. This becomes a bigger problem when trying to set
the line entry into a SymbolContext object and it discards it after
checking its validity.

This patch is necessary to extend ScriptedFrames ability to create
synthetic frames with invalid addresses and invalid line entries.

Signed-off-by: Med Ismail Bennani <[email protected]>

Author: medismailben

lldb/include/lldb/Breakpoint/BreakpointLocation.h

@@ -308,7 +308,8 @@ class BreakpointLocation
   /// The line entry must have the same start address as the address for this
   /// location.
   bool SetPreferredLineEntry(const LineEntry &line_entry) {
-    if (m_address == line_entry.range.GetBaseAddress()) {
+    if (line_entry.HasValidRange() &&
+        m_address == line_entry.GetRange().GetBaseAddress()) {
       m_preferred_line_entry = line_entry;
       return true;
     }

lldb/include/lldb/Symbol/LineEntry.h

@@ -13,6 +13,7 @@
 #include "lldb/Utility/FileSpec.h"
 #include "lldb/Utility/SupportFile.h"
 #include "lldb/lldb-private.h"
+#include <optional>
 
 namespace lldb_private {
 
@@ -133,8 +134,15 @@ struct LineEntry {
   /// Helper to access the file.
   const FileSpec &GetFile() const { return file_sp->GetSpecOnly(); }
 
-  /// The section offset address range for this line entry.
-  AddressRange range;
+  /// Get the address range for this line entry.
+  /// \return The address range if valid, otherwise an invalid AddressRange.
+  const AddressRange &GetRange() const;
+
+  /// Check if this line entry has a valid address range.
+  bool HasValidRange() const;
+
+  /// Set the address range for this line entry.
+  void SetRange(const AddressRange &range);
 
   /// The source file, possibly mapped by the target.source-map setting.
   SupportFileNSP file_sp;
@@ -167,6 +175,10 @@ struct LineEntry {
   /// Indicates this entry is that of the first byte after the end of a sequence
   /// of target machine instructions.
   uint16_t is_terminal_entry : 1;
+
+private:
+  /// The section offset address range for this line entry (optional).
+  std::optional<AddressRange> m_range;
 };
 
 /// Less than operator.

lldb/source/API/SBLineEntry.cpp

@@ -50,8 +50,8 @@ SBAddress SBLineEntry::GetStartAddress() const {
   LLDB_INSTRUMENT_VA(this);
 
   SBAddress sb_address;
-  if (m_opaque_up)
-    sb_address.SetAddress(m_opaque_up->range.GetBaseAddress());
+  if (m_opaque_up && m_opaque_up->HasValidRange())
+    sb_address.SetAddress(m_opaque_up->GetRange().GetBaseAddress());
 
   return sb_address;
 }
@@ -60,9 +60,9 @@ SBAddress SBLineEntry::GetEndAddress() const {
   LLDB_INSTRUMENT_VA(this);
 
   SBAddress sb_address;
-  if (m_opaque_up) {
-    sb_address.SetAddress(m_opaque_up->range.GetBaseAddress());
-    sb_address.OffsetAddress(m_opaque_up->range.GetByteSize());
+  if (m_opaque_up && m_opaque_up->HasValidRange()) {
+    sb_address.SetAddress(m_opaque_up->GetRange().GetBaseAddress());
+    sb_address.OffsetAddress(m_opaque_up->GetRange().GetByteSize());
   }
   return sb_address;
 }

lldb/source/API/SBThread.cpp

@@ -539,9 +539,14 @@ void SBThread::StepInto(const char *target_name, uint32_t end_line,
   if (frame_sp && frame_sp->HasDebugInformation()) {
     SymbolContext sc(frame_sp->GetSymbolContext(eSymbolContextEverything));
     AddressRange range;
-    if (end_line == LLDB_INVALID_LINE_NUMBER)
-      range = sc.line_entry.range;
-    else {
+    if (end_line == LLDB_INVALID_LINE_NUMBER) {
+      if (sc.line_entry.HasValidRange())
+        range = sc.line_entry.GetRange();
+      else {
+        error = Status::FromErrorString("No valid range for line entry");
+        return;
+      }
+    } else {
       llvm::Error err = sc.GetAddressRangeFromHereToEndLine(end_line, range);
       if (err) {
         error = Status::FromErrorString(llvm::toString(std::move(err)).c_str());
@@ -811,7 +816,7 @@ SBError SBThread::StepOverUntil(lldb::SBFrame &sb_frame,
                                              eSymbolContextLineEntry, sc_list);
     for (const SymbolContext &sc : sc_list) {
       addr_t step_addr =
-          sc.line_entry.range.GetBaseAddress().GetLoadAddress(target);
+          sc.line_entry.GetRange().GetBaseAddress().GetLoadAddress(target);
       if (step_addr != LLDB_INVALID_ADDRESS) {
         AddressRange unused_range;
         if (frame_sc.function->GetRangeContainingLoadAddress(step_addr, *target,

lldb/source/Breakpoint/BreakpointResolver.cpp

@@ -273,11 +273,19 @@ void BreakpointResolver::SetSCMatchesByLine(
     }
 
     // Sort by file address.
-    llvm::sort(worklist_begin, worklist_end,
-               [](const SymbolContext &a, const SymbolContext &b) {
-                 return a.line_entry.range.GetBaseAddress().GetFileAddress() <
-                        b.line_entry.range.GetBaseAddress().GetFileAddress();
-               });
+    llvm::sort(
+        worklist_begin, worklist_end,
+        [](const SymbolContext &a, const SymbolContext &b) {
+          auto a_addr =
+              a.line_entry.HasValidRange()
+                  ? a.line_entry.GetRange().GetBaseAddress().GetFileAddress()
+                  : LLDB_INVALID_ADDRESS;
+          auto b_addr =
+              b.line_entry.HasValidRange()
+                  ? b.line_entry.GetRange().GetBaseAddress().GetFileAddress()
+                  : LLDB_INVALID_ADDRESS;
+          return a_addr < b_addr;
+        });
 
     // Go through and see if there are line table entries that are
     // contiguous, and if so keep only the first of the contiguous range.
@@ -307,7 +315,9 @@ void BreakpointResolver::AddLocation(SearchFilter &filter,
                                      bool skip_prologue,
                                      llvm::StringRef log_ident) {
   Log *log = GetLog(LLDBLog::Breakpoints);
-  Address line_start = sc.line_entry.range.GetBaseAddress();
+  Address line_start = sc.line_entry.HasValidRange()
+                           ? sc.line_entry.GetRange().GetBaseAddress()
+                           : Address();
   if (!line_start.IsValid()) {
     LLDB_LOGF(log,
               "error: Unable to set breakpoint %s at file address "

lldb/source/Commands/CommandObjectDisassemble.cpp

@@ -356,8 +356,8 @@ CommandObjectDisassemble::GetCurrentLineRanges() {
 
   LineEntry pc_line_entry(
       frame->GetSymbolContext(eSymbolContextLineEntry).line_entry);
-  if (pc_line_entry.IsValid())
-    return std::vector<AddressRange>{pc_line_entry.range};
+  if (pc_line_entry.IsValid() && pc_line_entry.HasValidRange())
+    return std::vector<AddressRange>{pc_line_entry.GetRange()};
 
   // No line entry, so just disassemble around the current pc
   m_options.show_mixed = false;

lldb/source/Commands/CommandObjectSource.cpp

@@ -1032,9 +1032,11 @@ class CommandObjectSourceList : public CommandObjectParsed {
           bool show_inlined_frames = true;
           const bool show_function_arguments = true;
           const bool show_function_name = true;
+          Address addr = sc.line_entry.HasValidRange()
+                             ? sc.line_entry.GetRange().GetBaseAddress()
+                             : Address();
           sc.DumpStopContext(&result.GetOutputStream(),
-                             m_exe_ctx.GetBestExecutionContextScope(),
-                             sc.line_entry.range.GetBaseAddress(),
+                             m_exe_ctx.GetBestExecutionContextScope(), addr,
                              show_fullpaths, show_module, show_inlined_frames,
                              show_function_arguments, show_function_name);
           result.GetOutputStream().EOL();

lldb/source/Commands/CommandObjectTarget.cpp

@@ -1634,8 +1634,8 @@ static void DumpSymbolContextList(
       strm.EOL();
 
     Address addr;
-    if (sc.line_entry.IsValid())
-      addr = sc.line_entry.range.GetBaseAddress();
+    if (sc.line_entry.IsValid() && sc.line_entry.HasValidRange())
+      addr = sc.line_entry.GetRange().GetBaseAddress();
     else if (sc.block && sc.block->GetContainingInlinedBlock())
       sc.block->GetContainingInlinedBlock()->GetStartAddress(addr);
     else

lldb/source/Commands/CommandObjectThread.cpp

@@ -519,7 +519,7 @@ class CommandObjectThreadStepWithTypeAndScope : public CommandObjectParsed {
               block_range.GetByteSize() - pc_offset_in_block;
           range = AddressRange(pc_address, range_length);
         } else {
-          range = sc.line_entry.range;
+          range = sc.line_entry.GetRange();
         }
 
         new_plan_sp = thread->QueueThreadPlanForStepInRange(
@@ -999,7 +999,7 @@ class CommandObjectThreadUntil : public CommandObjectParsed {
           while (idx < end_func_idx) {
             if (line_idx_ranges.FindEntryIndexThatContains(idx) != UINT32_MAX) {
               addr_t address =
-                  line_entry.range.GetBaseAddress().GetLoadAddress(target);
+                  line_entry.GetRange().GetBaseAddress().GetLoadAddress(target);
               if (address != LLDB_INVALID_ADDRESS)
                 address_list.push_back(address);
             }

lldb/source/Core/AddressResolverFileLine.cpp

@@ -46,8 +46,8 @@ AddressResolverFileLine::SearchCallback(SearchFilter &filter,
   cu->ResolveSymbolContext(m_src_location_spec, eSymbolContextEverything,
                            sc_list);
   for (const SymbolContext &sc : sc_list) {
-    Address line_start = sc.line_entry.range.GetBaseAddress();
-    addr_t byte_size = sc.line_entry.range.GetByteSize();
+    Address line_start = sc.line_entry.GetRange().GetBaseAddress();
+    addr_t byte_size = sc.line_entry.GetRange().GetByteSize();
     if (line_start.IsValid()) {
       AddressRange new_range(line_start, byte_size);
       m_address_ranges.push_back(new_range);