[LoongArch] Add relaxDwarfLineAddr and relaxDwarfCFA to handle the mutable label diff in dwarfinfo

llvm/lib/Object/RelocationResolver.cpp

@@ -538,6 +538,8 @@ static bool supportsLoongArch(uint64_t Type) {
   case ELF::R_LARCH_32:
   case ELF::R_LARCH_32_PCREL:
   case ELF::R_LARCH_64:
+  case ELF::R_LARCH_ADD6:
+  case ELF::R_LARCH_SUB6:
   case ELF::R_LARCH_ADD8:
   case ELF::R_LARCH_SUB8:
   case ELF::R_LARCH_ADD16:
@@ -563,6 +565,10 @@ static uint64_t resolveLoongArch(uint64_t Type, uint64_t Offset, uint64_t S,
     return (S + Addend - Offset) & 0xFFFFFFFF;
   case ELF::R_LARCH_64:
     return S + Addend;
+  case ELF::R_LARCH_ADD6:
+    return (LocData & 0xC0) | ((LocData + S + Addend) & 0x3F);
+  case ELF::R_LARCH_SUB6:
+    return (LocData & 0xC0) | ((LocData - (S + Addend)) & 0x3F);
   case ELF::R_LARCH_ADD8:
     return (LocData + (S + Addend)) & 0xFF;
   case ELF::R_LARCH_SUB8:
@@ -879,9 +885,11 @@ uint64_t resolveRelocation(RelocationResolver Resolver, const RelocationRef &R,
 
       if (GetRelSectionType() == ELF::SHT_RELA) {
         Addend = getELFAddend(R);
-        // RISCV relocations use both LocData and Addend.
+        // RISCV, LoongArch relocations use both LocData and Addend.
         if (Obj->getArch() != Triple::riscv32 &&
-            Obj->getArch() != Triple::riscv64)
+            Obj->getArch() != Triple::riscv64 &&
+            Obj->getArch() != Triple::loongarch32 &&
+            Obj->getArch() != Triple::loongarch64)
           LocData = 0;
       }
     }

llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.cpp

@@ -12,12 +12,14 @@
 
 #include "LoongArchAsmBackend.h"
 #include "LoongArchFixupKinds.h"
+#include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MCAsmLayout.h"
 #include "llvm/MC/MCAssembler.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCELFObjectWriter.h"
 #include "llvm/MC/MCValue.h"
 #include "llvm/Support/EndianStream.h"
+#include "llvm/Support/LEB128.h"
 
 #define DEBUG_TYPE "loongarch-asmbackend"
 
@@ -235,6 +237,133 @@ std::pair<bool, bool> LoongArchAsmBackend::relaxLEB128(MCLEBFragment &LF,
   return std::make_pair(true, true);
 }
 
+bool LoongArchAsmBackend::relaxDwarfLineAddr(MCDwarfLineAddrFragment &DF,
+                                             MCAsmLayout &Layout,
+                                             bool &WasRelaxed) const {
+  MCContext &C = Layout.getAssembler().getContext();
+
+  int64_t LineDelta = DF.getLineDelta();
+  const MCExpr &AddrDelta = DF.getAddrDelta();
+  SmallVectorImpl<char> &Data = DF.getContents();
+  SmallVectorImpl<MCFixup> &Fixups = DF.getFixups();
+  size_t OldSize = Data.size();
+
+  int64_t Value;
+  if (AddrDelta.evaluateAsAbsolute(Value, Layout))
+    return false;
+  bool IsAbsolute = AddrDelta.evaluateKnownAbsolute(Value, Layout);
+  assert(IsAbsolute && "CFA with invalid expression");
+  (void)IsAbsolute;
+
+  Data.clear();
+  Fixups.clear();
+  raw_svector_ostream OS(Data);
+
+  // INT64_MAX is a signal that this is actually a DW_LNE_end_sequence.
+  if (LineDelta != INT64_MAX) {
+    OS << uint8_t(dwarf::DW_LNS_advance_line);
+    encodeSLEB128(LineDelta, OS);
+  }
+
+  unsigned Offset;
+  std::pair<MCFixupKind, MCFixupKind> FK;
+
+  // According to the DWARF specification, the `DW_LNS_fixed_advance_pc` opcode
+  // takes a single unsigned half (unencoded) operand. The maximum encodable
+  // value is therefore 65535.  Set a conservative upper bound for relaxation.
+  if (Value > 60000) {
+    unsigned PtrSize = C.getAsmInfo()->getCodePointerSize();
+
+    OS << uint8_t(dwarf::DW_LNS_extended_op);
+    encodeULEB128(PtrSize + 1, OS);
+
+    OS << uint8_t(dwarf::DW_LNE_set_address);
+    Offset = OS.tell();
+    assert((PtrSize == 4 || PtrSize == 8) && "Unexpected pointer size");
+    FK = getRelocPairForSize(PtrSize == 4 ? 32 : 64);
+    OS.write_zeros(PtrSize);
+  } else {
+    OS << uint8_t(dwarf::DW_LNS_fixed_advance_pc);
+    Offset = OS.tell();
+    FK = getRelocPairForSize(16);
+    support::endian::write<uint16_t>(OS, 0, llvm::endianness::little);
+  }
+
+  const MCBinaryExpr &MBE = cast<MCBinaryExpr>(AddrDelta);
+  Fixups.push_back(MCFixup::create(Offset, MBE.getLHS(), std::get<0>(FK)));
+  Fixups.push_back(MCFixup::create(Offset, MBE.getRHS(), std::get<1>(FK)));
+
+  if (LineDelta == INT64_MAX) {
+    OS << uint8_t(dwarf::DW_LNS_extended_op);
+    OS << uint8_t(1);
+    OS << uint8_t(dwarf::DW_LNE_end_sequence);
+  } else {
+    OS << uint8_t(dwarf::DW_LNS_copy);
+  }
+
+  WasRelaxed = OldSize != Data.size();
+  return true;
+}
+
+bool LoongArchAsmBackend::relaxDwarfCFA(MCDwarfCallFrameFragment &DF,
+                                        MCAsmLayout &Layout,
+                                        bool &WasRelaxed) const {
+  const MCExpr &AddrDelta = DF.getAddrDelta();
+  SmallVectorImpl<char> &Data = DF.getContents();
+  SmallVectorImpl<MCFixup> &Fixups = DF.getFixups();
+  size_t OldSize = Data.size();
+
+  int64_t Value;
+  if (AddrDelta.evaluateAsAbsolute(Value, Layout))
+    return false;
+  bool IsAbsolute = AddrDelta.evaluateKnownAbsolute(Value, Layout);
+  assert(IsAbsolute && "CFA with invalid expression");
+  (void)IsAbsolute;
+
+  Data.clear();
+  Fixups.clear();
+  raw_svector_ostream OS(Data);
+
+  assert(
+      Layout.getAssembler().getContext().getAsmInfo()->getMinInstAlignment() ==
+          1 &&
+      "expected 1-byte alignment");
+  if (Value == 0) {
+    WasRelaxed = OldSize != Data.size();
+    return true;
+  }
+
+  auto AddFixups = [&Fixups,
+                    &AddrDelta](unsigned Offset,
+                                std::pair<MCFixupKind, MCFixupKind> FK) {
+    const MCBinaryExpr &MBE = cast<MCBinaryExpr>(AddrDelta);
+    Fixups.push_back(MCFixup::create(Offset, MBE.getLHS(), std::get<0>(FK)));
+    Fixups.push_back(MCFixup::create(Offset, MBE.getRHS(), std::get<1>(FK)));
+  };
+
+  if (isUIntN(6, Value)) {
+    OS << uint8_t(dwarf::DW_CFA_advance_loc);
+    AddFixups(0, getRelocPairForSize(6));
+  } else if (isUInt<8>(Value)) {
+    OS << uint8_t(dwarf::DW_CFA_advance_loc1);
+    support::endian::write<uint8_t>(OS, 0, llvm::endianness::little);
+    AddFixups(1, getRelocPairForSize(8));
+  } else if (isUInt<16>(Value)) {
+    OS << uint8_t(dwarf::DW_CFA_advance_loc2);
+    support::endian::write<uint16_t>(OS, 0, llvm::endianness::little);
+    AddFixups(1, getRelocPairForSize(16));
+  } else if (isUInt<32>(Value)) {
+    OS << uint8_t(dwarf::DW_CFA_advance_loc4);
+    support::endian::write<uint32_t>(OS, 0, llvm::endianness::little);
+    AddFixups(1, getRelocPairForSize(32));
+  } else {
+    llvm_unreachable("unsupported CFA encoding");
+  }
+
+  WasRelaxed = OldSize != Data.size();
+  return true;
+}
+
 bool LoongArchAsmBackend::writeNopData(raw_ostream &OS, uint64_t Count,
                                        const MCSubtargetInfo *STI) const {
   // We mostly follow binutils' convention here: align to 4-byte boundary with a

llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.h

@@ -69,6 +69,11 @@ class LoongArchAsmBackend : public MCAsmBackend {
   std::pair<bool, bool> relaxLEB128(MCLEBFragment &LF, MCAsmLayout &Layout,
                                     int64_t &Value) const override;
 
+  bool relaxDwarfLineAddr(MCDwarfLineAddrFragment &DF, MCAsmLayout &Layout,
+                          bool &WasRelaxed) const override;
+  bool relaxDwarfCFA(MCDwarfCallFrameFragment &DF, MCAsmLayout &Layout,
+                     bool &WasRelaxed) const override;
+
   bool writeNopData(raw_ostream &OS, uint64_t Count,
                     const MCSubtargetInfo *STI) const override;
 

llvm/test/DebugInfo/LoongArch/dwarf-loongarch-relocs.ll

@@ -0,0 +1,128 @@
+; RUN: llc --filetype=obj --mtriple=loongarch64 --mattr=-relax %s -o %t.o
+; RUN: llvm-readobj -r %t.o | FileCheck -check-prefixes=RELOCS-BOTH,RELOCS-NORL %s
+; RUN: llvm-objdump --source %t.o | FileCheck --check-prefix=SOURCE %s
+; RUN: llvm-dwarfdump --debug-info --debug-line %t.o | FileCheck -check-prefix=DWARF %s
+
+; RUN: llc --filetype=obj --mtriple=loongarch64 --mattr=+relax %s -o %t.r.o
+; RUN: llvm-readobj -r %t.r.o | FileCheck -check-prefixes=RELOCS-BOTH,RELOCS-ENRL %s
+; RUN: llvm-objdump --source %t.r.o | FileCheck --check-prefix=SOURCE %s
+; RUN: llvm-dwarfdump --debug-info --debug-line %t.r.o | FileCheck -check-prefix=DWARF %s
+
+; RELOCS-BOTH:       Relocations [
+; RELOCS-BOTH-NEXT:    Section ({{.*}}) .rela.text {
+; RELOCS-BOTH-NEXT:      0x14 R_LARCH_PCALA_HI20 sym 0x0
+; RELOCS-ENRL-NEXT:      0x14 R_LARCH_RELAX - 0x0
+; RELOCS-BOTH-NEXT:      0x18 R_LARCH_PCALA_LO12 sym 0x0
+; RELOCS-ENRL-NEXT:      0x18 R_LARCH_RELAX - 0x0
+; RELOCS-BOTH-NEXT:    }
+; RELOCS-BOTH:         Section ({{.*}}) .rela.debug_frame {
+; RELOCS-NORL-NEXT:      0x1C R_LARCH_32 .debug_frame 0x0
+; RELOCS-NORL-NEXT:      0x20 R_LARCH_64 .text 0x0
+; RELOCS-ENRL-NEXT:      0x1C R_LARCH_32 <null> 0x0
+; RELOCS-ENRL-NEXT:      0x20 R_LARCH_64 <null> 0x0
+; RELOCS-ENRL-NEXT:      0x28 R_LARCH_ADD64 <null> 0x0
+; RELOCS-ENRL-NEXT:      0x28 R_LARCH_SUB64 <null> 0x0
+; RELOCS-ENRL-NEXT:      0x3F R_LARCH_ADD6 <null> 0x0
+; RELOCS-ENRL-NEXT:      0x3F R_LARCH_SUB6 <null> 0x0
+; RELOCS-BOTH-NEXT:    }
+; RELOCS-BOTH:         Section ({{.*}}) .rela.debug_line {
+; RELOCS-BOTH-NEXT:      0x22 R_LARCH_32 .debug_line_str 0x0
+; RELOCS-BOTH-NEXT:      0x31 R_LARCH_32 .debug_line_str 0x2
+; RELOCS-BOTH-NEXT:      0x46 R_LARCH_32 .debug_line_str 0x1B
+; RELOCS-NORL-NEXT:      0x4F R_LARCH_64 .text 0x0
+; RELOCS-ENRL-NEXT:      0x4F R_LARCH_64 <null> 0x0
+; RELOCS-ENRL-NEXT:      0x5F R_LARCH_ADD16 <null> 0x0
+; RELOCS-ENRL-NEXT:      0x5F R_LARCH_SUB16 <null> 0x0
+; RELOCS-BOTH-NEXT:    }
+; RELOCS-BOTH-NEXT:  ]
+
+; SOURCE:  0000000000000000 <foo>:
+; SOURCE:  ; {
+; SOURCE:  ;   asm volatile(
+; SOURCE:  ;   return 0;
+
+; DWARF:       DW_AT_producer ("clang")
+; DWARF:       DW_AT_name ("dwarf-loongarch-relocs.c")
+; DWARF:       DW_AT_comp_dir (".")
+; DWARF:       DW_AT_name ("foo")
+; DWARF-NEXT:  DW_AT_decl_file ("{{.*}}dwarf-loongarch-relocs.c")
+; DWARF-NEXT:  DW_AT_decl_line (1)
+; DWARF-NEXT:  DW_AT_type (0x00000032 "int")
+; DWARF:       DW_AT_name ("int")
+; DWARF-NEXT:  DW_AT_encoding (DW_ATE_signed)
+; DWARF-NEXT:  DW_AT_byte_size (0x04)
+; DWARF:       .debug_line contents:
+; DWARF-NEXT:  debug_line[0x00000000]
+; DWARF-NEXT:  Line table prologue:
+; DWARF-NEXT:      total_length: {{.*}}
+; DWARF-NEXT:            format: DWARF32
+; DWARF-NEXT:           version: 5
+; DWARF-NEXT:      address_size: 8
+; DWARF-NEXT:   seg_select_size: 0
+; DWARF-NEXT:   prologue_length: 0x0000003e
+; DWARF-NEXT:   min_inst_length: 1
+; DWARF-NEXT:  max_ops_per_inst: 1
+; DWARF-NEXT:   default_is_stmt: 1
+; DWARF-NEXT:         line_base: -5
+; DWARF-NEXT:        line_range: 14
+; DWARF-NEXT:       opcode_base: 13
+; DWARF-NEXT:  standard_opcode_lengths[DW_LNS_copy] = 0
+; DWARF-NEXT:  standard_opcode_lengths[DW_LNS_advance_pc] = 1
+; DWARF-NEXT:  standard_opcode_lengths[DW_LNS_advance_line] = 1
+; DWARF-NEXT:  standard_opcode_lengths[DW_LNS_set_file] = 1
+; DWARF-NEXT:  standard_opcode_lengths[DW_LNS_set_column] = 1
+; DWARF-NEXT:  standard_opcode_lengths[DW_LNS_negate_stmt] = 0
+; DWARF-NEXT:  standard_opcode_lengths[DW_LNS_set_basic_block] = 0
+; DWARF-NEXT:  standard_opcode_lengths[DW_LNS_const_add_pc] = 0
+; DWARF-NEXT:  standard_opcode_lengths[DW_LNS_fixed_advance_pc] = 1
+; DWARF-NEXT:  standard_opcode_lengths[DW_LNS_set_prologue_end] = 0
+; DWARF-NEXT:  standard_opcode_lengths[DW_LNS_set_epilogue_begin] = 0
+; DWARF-NEXT:  standard_opcode_lengths[DW_LNS_set_isa] = 1
+; DWARF-NEXT:  include_directories[  0] = "."
+; DWARF-NEXT:  file_names[  0]:
+; DWARF-NEXT:             name: "dwarf-loongarch-relocs.c"
+; DWARF-NEXT:        dir_index: 0
+; DWARF-NEXT:     md5_checksum: f44d6d71bc4da58b4abe338ca507c007
+; DWARF-NEXT:           source: "{{.*}}"
+; DWARF-EMPTY:
+; DWARF-NEXT:  Address            Line   Column File   ISA Discriminator OpIndex Flags
+; DWARF-NEXT:  ------------------ ------ ------ ------ --- ------------- ------- -------------
+; DWARF-NEXT:  0x0000000000000000      2      0      0   0             0       0  is_stmt
+; DWARF-NEXT:  0x0000000000000010      3      3      0   0             0       0  is_stmt prologue_end
+; DWARF-NEXT:  0x0000000000000020     10      3      0   0             0       0  is_stmt
+; DWARF-NEXT:  0x000000000000002c     10      3      0   0             0       0  epilogue_begin
+; DWARF-NEXT:  0x0000000000000034     10      3      0   0             0       0  end_sequence
+
+; ModuleID = 'dwarf-loongarch-relocs.c'
+source_filename = "dwarf-loongarch-relocs.c"
+target datalayout = "e-m:e-p:64:64-i64:64-i128:128-n64-S128"
+target triple = "loongarch64"
+
+; Function Attrs: noinline nounwind optnone
+define dso_local signext i32 @foo() #0 !dbg !8 {
+  call void asm sideeffect ".cfi_remember_state\0A\09.cfi_adjust_cfa_offset 16\0A\09nop\0A\09la.pcrel $$t0, sym\0A\09nop\0A\09.cfi_restore_state\0A\09", ""() #1, !dbg !12, !srcloc !13
+  ret i32 0, !dbg !14
+}
+
+attributes #0 = { noinline nounwind optnone "frame-pointer"="all" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="loongarch64" "target-features"="+64bit,+d,+f,+ual" }
+attributes #1 = { nounwind }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!2, !3, !4, !5, !6}
+!llvm.ident = !{!7}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C11, file: !1, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None)
+!1 = !DIFile(filename: "dwarf-loongarch-relocs.c", directory: ".", checksumkind: CSK_MD5, checksum: "f44d6d71bc4da58b4abe338ca507c007", source: "int foo()\0A{\0A  asm volatile(\0A    \22.cfi_remember_state\\n\\t\22\0A    \22.cfi_adjust_cfa_offset 16\\n\\t\22\0A    \22nop\\n\\t\22\0A    \22la.pcrel $t0, sym\\n\\t\22\0A    \22nop\\n\\t\22\0A    \22.cfi_restore_state\\n\\t\22);\0A  return 0;\0A}\0A")
+!2 = !{i32 7, !"Dwarf Version", i32 5}
+!3 = !{i32 2, !"Debug Info Version", i32 3}
+!4 = !{i32 1, !"wchar_size", i32 4}
+!5 = !{i32 7, !"direct-access-external-data", i32 0}
+!6 = !{i32 7, !"frame-pointer", i32 2}
+!7 = !{!"clang"}
+!8 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 1, type: !9, scopeLine: 2, spFlags: DISPFlagDefinition, unit: !0)
+!9 = !DISubroutineType(types: !10)
+!10 = !{!11}
+!11 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!12 = !DILocation(line: 3, column: 3, scope: !8)
+!13 = !{i64 34, i64 56, i64 92, i64 106, i64 134, i64 148, i64 177}
+!14 = !DILocation(line: 10, column: 3, scope: !8)

llvm/test/DebugInfo/LoongArch/lit.local.cfg

@@ -0,0 +1,2 @@
+if not "LoongArch" in config.root.targets:
+    config.unsupported = True