[NFC] Remove UnwindTable dependency on CIE, and FDE (#142520)

amsen20 · web-flow · commit b9d1642423f8 · 2025-06-23T23:15:18.000-07:00
This PR is in the direction of separating Unwind table from FDE, and CIE that depends on llvm/Object. To separate, first the runtime dependencies have to be removed, which this commit does that. This is similar to [1](#140096), [2](#139175), and [3](#139326).
diff --git a/llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h b/llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h
@@ -311,9 +311,6 @@ class UnwindRow {
 
 LLVM_ABI raw_ostream &operator<<(raw_ostream &OS, const UnwindRow &Row);
 
-class CIE;
-class FDE;
-
 /// A class that contains all UnwindRow objects for an FDE or a single unwind
 /// row for a CIE. To unwind an address the rows, which are sorted by start
 /// address, can be searched to find the UnwindRow with the lowest starting
@@ -325,6 +322,8 @@ class UnwindTable {
   using iterator = RowContainer::iterator;
   using const_iterator = RowContainer::const_iterator;
 
+  UnwindTable(RowContainer &&Rows) : Rows(std::move(Rows)) {}
+
   size_t size() const { return Rows.size(); }
   iterator begin() { return Rows.begin(); }
   const_iterator begin() const { return Rows.begin(); }
@@ -339,7 +338,7 @@ class UnwindTable {
   ///
   /// \param OS the stream to use for output.
   ///
-  /// \param MRI register information that helps emit register names insteead
+  /// \param MRI register information that helps emit register names instead
   /// of raw register numbers.
   ///
   /// \param IsEH true if the DWARF Call Frame Information is from .eh_frame
@@ -352,53 +351,57 @@ class UnwindTable {
   LLVM_ABI void dump(raw_ostream &OS, DIDumpOptions DumpOpts,
                      unsigned IndentLevel = 0) const;
 
-  /// Create an UnwindTable from a Common Information Entry (CIE).
-  ///
-  /// \param Cie The Common Information Entry to extract the table from. The
-  /// CFIProgram is retrieved from the \a Cie object and used to create the
-  /// UnwindTable.
-  ///
-  /// \returns An error if the DWARF Call Frame Information opcodes have state
-  /// machine errors, or a valid UnwindTable otherwise.
-  LLVM_ABI static Expected<UnwindTable> create(const CIE *Cie);
-
-  /// Create an UnwindTable from a Frame Descriptor Entry (FDE).
-  ///
-  /// \param Fde The Frame Descriptor Entry to extract the table from. The
-  /// CFIProgram is retrieved from the \a Fde object and used to create the
-  /// UnwindTable.
-  ///
-  /// \returns An error if the DWARF Call Frame Information opcodes have state
-  /// machine errors, or a valid UnwindTable otherwise.
-  LLVM_ABI static Expected<UnwindTable> create(const FDE *Fde);
-
 private:
   RowContainer Rows;
-  /// The end address when data is extracted from a FDE. This value will be
-  /// invalid when a UnwindTable is extracted from a CIE.
-  std::optional<uint64_t> EndAddress;
-
-  /// Parse the information in the CFIProgram and update the CurrRow object
-  /// that the state machine describes.
-  ///
-  /// This is an internal implementation that emulates the state machine
-  /// described in the DWARF Call Frame Information opcodes and will push
-  /// CurrRow onto the Rows container when needed.
-  ///
-  /// \param CFIP the CFI program that contains the opcodes from a CIE or FDE.
-  ///
-  /// \param CurrRow the current row to modify while parsing the state machine.
-  ///
-  /// \param InitialLocs If non-NULL, we are parsing a FDE and this contains
-  /// the initial register locations from the CIE. If NULL, then a CIE's
-  /// opcodes are being parsed and this is not needed. This is used for the
-  /// DW_CFA_restore and DW_CFA_restore_extended opcodes.
-  Error parseRows(const CFIProgram &CFIP, UnwindRow &CurrRow,
-                  const RegisterLocations *InitialLocs);
 };
 
+/// Parse the information in the CFIProgram and update the CurrRow object
+/// that the state machine describes.
+///
+/// This function emulates the state machine described in the DWARF Call Frame
+/// Information opcodes and will push CurrRow onto a RowContainer when needed.
+///
+/// \param CFIP the CFI program that contains the opcodes from a CIE or FDE.
+///
+/// \param CurrRow the current row to modify while parsing the state machine.
+///
+/// \param InitialLocs If non-NULL, we are parsing a FDE and this contains
+/// the initial register locations from the CIE. If NULL, then a CIE's
+/// opcodes are being parsed and this is not needed. This is used for the
+/// DW_CFA_restore and DW_CFA_restore_extended opcodes.
+///
+/// \returns An error if the DWARF Call Frame Information opcodes have state
+/// machine errors, or the accumulated rows otherwise.
+LLVM_ABI Expected<UnwindTable::RowContainer>
+parseRows(const CFIProgram &CFIP, UnwindRow &CurrRow,
+          const RegisterLocations *InitialLocs);
+
 LLVM_ABI raw_ostream &operator<<(raw_ostream &OS, const UnwindTable &Rows);
 
+class CIE;
+
+/// Create an UnwindTable from a Common Information Entry (CIE).
+///
+/// \param Cie The Common Information Entry to extract the table from. The
+/// CFIProgram is retrieved from the \a Cie object and used to create the
+/// UnwindTable.
+///
+/// \returns An error if the DWARF Call Frame Information opcodes have state
+/// machine errors, or a valid UnwindTable otherwise.
+LLVM_ABI Expected<UnwindTable> createUnwindTable(const CIE *Cie);
+
+class FDE;
+
+/// Create an UnwindTable from a Frame Descriptor Entry (FDE).
+///
+/// \param Fde The Frame Descriptor Entry to extract the table from. The
+/// CFIProgram is retrieved from the \a Fde object and used to create the
+/// UnwindTable.
+///
+/// \returns An error if the DWARF Call Frame Information opcodes have state
+/// machine errors, or a valid UnwindTable otherwise.
+LLVM_ABI Expected<UnwindTable> createUnwindTable(const FDE *Fde);
+
 /// An entry in either debug_frame or eh_frame. This entry can be a CIE or an
 /// FDE.
 class FrameEntry {
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFDebugFrame.cpp b/llvm/lib/DebugInfo/DWARF/DWARFDebugFrame.cpp
@@ -19,6 +19,7 @@
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/DataExtractor.h"
 #include "llvm/Support/Errc.h"
+#include "llvm/Support/Error.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/raw_ostream.h"
@@ -204,7 +205,7 @@ raw_ostream &llvm::dwarf::operator<<(raw_ostream &OS, const UnwindTable &Rows) {
   return OS;
 }
 
-Expected<UnwindTable> UnwindTable::create(const FDE *Fde) {
+Expected<UnwindTable> llvm::dwarf::createUnwindTable(const FDE *Fde) {
   const CIE *Cie = Fde->getLinkedCIE();
   if (Cie == nullptr)
     return createStringError(errc::invalid_argument,
@@ -213,46 +214,56 @@ Expected<UnwindTable> UnwindTable::create(const FDE *Fde) {
 
   // Rows will be empty if there are no CFI instructions.
   if (Cie->cfis().empty() && Fde->cfis().empty())
-    return UnwindTable();
+    return UnwindTable({});
 
-  UnwindTable UT;
+  UnwindTable::RowContainer CieRows;
   UnwindRow Row;
   Row.setAddress(Fde->getInitialLocation());
-  UT.EndAddress = Fde->getInitialLocation() + Fde->getAddressRange();
-  if (Error CieError = UT.parseRows(Cie->cfis(), Row, nullptr))
+  if (Error CieError = parseRows(Cie->cfis(), Row, nullptr).moveInto(CieRows))
     return std::move(CieError);
   // We need to save the initial locations of registers from the CIE parsing
   // in case we run into DW_CFA_restore or DW_CFA_restore_extended opcodes.
+  UnwindTable::RowContainer FdeRows;
   const RegisterLocations InitialLocs = Row.getRegisterLocations();
-  if (Error FdeError = UT.parseRows(Fde->cfis(), Row, &InitialLocs))
+  if (Error FdeError =
+          parseRows(Fde->cfis(), Row, &InitialLocs).moveInto(FdeRows))
     return std::move(FdeError);
+
+  UnwindTable::RowContainer AllRows;
+  AllRows.insert(AllRows.end(), CieRows.begin(), CieRows.end());
+  AllRows.insert(AllRows.end(), FdeRows.begin(), FdeRows.end());
+
   // May be all the CFI instructions were DW_CFA_nop amd Row becomes empty.
   // Do not add that to the unwind table.
   if (Row.getRegisterLocations().hasLocations() ||
       Row.getCFAValue().getLocation() != UnwindLocation::Unspecified)
-    UT.Rows.push_back(Row);
-  return UT;
+    AllRows.push_back(Row);
+  return UnwindTable(std::move(AllRows));
 }
 
-Expected<UnwindTable> UnwindTable::create(const CIE *Cie) {
+Expected<UnwindTable> llvm::dwarf::createUnwindTable(const CIE *Cie) {
   // Rows will be empty if there are no CFI instructions.
   if (Cie->cfis().empty())
-    return UnwindTable();
+    return UnwindTable({});
 
-  UnwindTable UT;
+  UnwindTable::RowContainer Rows;
   UnwindRow Row;
-  if (Error CieError = UT.parseRows(Cie->cfis(), Row, nullptr))
+  if (Error CieError = parseRows(Cie->cfis(), Row, nullptr).moveInto(Rows))
     return std::move(CieError);
   // May be all the CFI instructions were DW_CFA_nop amd Row becomes empty.
   // Do not add that to the unwind table.
   if (Row.getRegisterLocations().hasLocations() ||
       Row.getCFAValue().getLocation() != UnwindLocation::Unspecified)
-    UT.Rows.push_back(Row);
-  return UT;
+    Rows.push_back(Row);
+  return UnwindTable(std::move(Rows));
 }
 
-Error UnwindTable::parseRows(const CFIProgram &CFIP, UnwindRow &Row,
-                             const RegisterLocations *InitialLocs) {
+Expected<UnwindTable::RowContainer>
+llvm::dwarf::parseRows(const CFIProgram &CFIP, UnwindRow &Row,
+                       const RegisterLocations *InitialLocs) {
+  // All the unwinding rows parsed during processing of the CFI program.
+  UnwindTable::RowContainer Rows;
+
   // State consists of CFA value and register locations.
   std::vector<std::pair<UnwindLocation, RegisterLocations>> States;
   for (const CFIProgram::Instruction &Inst : CFIP) {
@@ -554,7 +565,7 @@ Error UnwindTable::parseRows(const CFIProgram &CFIP, UnwindRow &Row,
       break;
     }
   }
-  return Error::success();
+  return Rows;
 }
 
 // Returns the CIE identifier to be used by the requested format.
@@ -607,7 +618,7 @@ void CIE::dump(raw_ostream &OS, DIDumpOptions DumpOpts) const {
                   /*InitialLocation=*/{});
   OS << "\n";
 
-  if (Expected<UnwindTable> RowsOrErr = UnwindTable::create(this))
+  if (Expected<UnwindTable> RowsOrErr = createUnwindTable(this))
     RowsOrErr->dump(OS, DumpOpts, 1);
   else {
     DumpOpts.RecoverableErrorHandler(joinErrors(
@@ -635,7 +646,7 @@ void FDE::dump(raw_ostream &OS, DIDumpOptions DumpOpts) const {
   printCFIProgram(CFIs, OS, DumpOpts, /*IndentLevel=*/1, InitialLocation);
   OS << "\n";
 
-  if (Expected<UnwindTable> RowsOrErr = UnwindTable::create(this))
+  if (Expected<UnwindTable> RowsOrErr = createUnwindTable(this))
     RowsOrErr->dump(OS, DumpOpts, 1);
   else {
     DumpOpts.RecoverableErrorHandler(joinErrors(
diff --git a/llvm/unittests/DebugInfo/DWARF/DWARFDebugFrameTest.cpp b/llvm/unittests/DebugInfo/DWARF/DWARFDebugFrameTest.cpp
