llvm-mc: Support .zerofill emission.

- I'm still trying to figure out the cleanest way to implement this and match the assembler, currently there are some substantial differences.

llvm-svn: 80347

include/llvm/MC/MCAssembler.h

@@ -33,7 +33,8 @@ public:
     FT_Data,
     FT_Align,
     FT_Fill,
-    FT_Org
+    FT_Org,
+    FT_ZeroFill
   };
 
 private:
@@ -218,6 +219,7 @@ public:
   MCOrgFragment(MCValue _Offset, int8_t _Value, MCSectionData *SD = 0)
     : MCFragment(FT_Org, SD),
       Offset(_Offset), Value(_Value) {}
+
   /// @name Accessors
   /// @{
 
@@ -238,6 +240,40 @@ public:
   static bool classof(const MCOrgFragment *) { return true; }
 };
 
+/// MCZeroFillFragment - Represent data which has a fixed size and alignment,
+/// but requires no physical space in the object file.
+class MCZeroFillFragment : public MCFragment {
+  /// Size - The size of this fragment.
+  uint64_t Size;
+
+  /// Alignment - The alignment for this fragment.
+  unsigned Alignment;
+
+public:
+  MCZeroFillFragment(uint64_t _Size, unsigned _Alignment, MCSectionData *SD = 0)
+    : MCFragment(FT_ZeroFill, SD),
+      Size(_Size), Alignment(_Alignment) {}
+
+  /// @name Accessors
+  /// @{
+
+  uint64_t getMaxFileSize() const {
+    // FIXME: This also doesn't make much sense, this method is misnamed.
+    return ~UINT64_C(0);
+  }
+
+  uint64_t getSize() const { return Size; }
+  
+  unsigned getAlignment() const { return Alignment; }
+
+  /// @}
+
+  static bool classof(const MCFragment *F) { 
+    return F->getKind() == MCFragment::FT_ZeroFill; 
+  }
+  static bool classof(const MCZeroFillFragment *) { return true; }
+};
+
 // FIXME: Should this be a separate class, or just merged into MCSection? Since
 // we anticipate the fast path being through an MCAssembler, the only reason to
 // keep it out is for API abstraction.

lib/MC/MCAssembler.cpp

@@ -28,6 +28,15 @@ STATISTIC(EmittedFragments, "Number of emitted assembler fragments");
 static void WriteFileData(raw_ostream &OS, const MCSectionData &SD,
                           MachObjectWriter &MOW);
 
+/// isVirtualSection - Check if this is a section which does not actually exist
+/// in the object file.
+static bool isVirtualSection(const MCSection &Section) {
+  // FIXME: Lame.
+  const MCSectionMachO &SMO = static_cast<const MCSectionMachO&>(Section);
+  unsigned Type = SMO.getTypeAndAttributes() & MCSectionMachO::SECTION_TYPE;
+  return (Type == MCSectionMachO::S_ZEROFILL);
+}
+
 class MachObjectWriter {
   // See <mach-o/loader.h>.
   enum {
@@ -229,6 +238,12 @@ public:
 
   void WriteSection32(const MCSectionData &SD, uint64_t FileOffset,
                       uint64_t RelocationsStart, unsigned NumRelocations) {
+    // The offset is unused for virtual sections.
+    if (isVirtualSection(SD.getSection())) {
+      assert(SD.getFileSize() == 0 && "Invalid file size!");
+      FileOffset = 0;
+    }
+
     // struct section (68 bytes)
 
     uint64_t Start = OS.tell();
@@ -692,6 +707,9 @@ public:
 
       VMSize = std::max(VMSize, SD.getAddress() + SD.getSize());
 
+      if (isVirtualSection(SD.getSection()))
+        continue;
+
       SectionDataSize = std::max(SectionDataSize,
                                  SD.getAddress() + SD.getSize());
       SectionDataFileSize = std::max(SectionDataFileSize, 
@@ -922,7 +940,7 @@ void MCAssembler::LayoutSection(MCSectionData &SD) {
     case MCFragment::FT_Align: {
       MCAlignFragment &AF = cast<MCAlignFragment>(F);
       
-      uint64_t Size = RoundUpToAlignment(Address, AF.getAlignment()) - Address;
+      uint64_t Size = OffsetToAlignment(Address, AF.getAlignment());
       if (Size > AF.getMaxBytesToEmit())
         AF.setFileSize(0);
       else
@@ -968,6 +986,19 @@ void MCAssembler::LayoutSection(MCSectionData &SD) {
       F.setFileSize(OrgOffset - Offset);
       break;
     }      
+
+    case MCFragment::FT_ZeroFill: {
+      MCZeroFillFragment &ZFF = cast<MCZeroFillFragment>(F);
+
+      // Align the fragment offset; it is safe to adjust the offset freely since
+      // this is only in virtual sections.
+      uint64_t Aligned = RoundUpToAlignment(Address, ZFF.getAlignment());
+      F.setOffset(Aligned - SD.getAddress());
+
+      // FIXME: This is misnamed.
+      F.setFileSize(ZFF.getSize());
+      break;
+    }
     }
 
     Address += F.getFileSize();
@@ -975,6 +1006,9 @@ void MCAssembler::LayoutSection(MCSectionData &SD) {
 
   // Set the section sizes.
   SD.setSize(Address - SD.getAddress());
+  if (isVirtualSection(SD.getSection()))
+    SD.setFileSize(0);
+  else
     SD.setFileSize(Address - SD.getAddress());
 }
 
@@ -1055,6 +1089,11 @@ static void WriteFileData(raw_ostream &OS, const MCFragment &F,
 
     break;
   }
+
+  case MCFragment::FT_ZeroFill: {
+    assert(0 && "Invalid zero fill fragment in concrete section!");
+    break;
+  }
   }
 
   assert(OS.tell() - Start == F.getFileSize());
@@ -1063,6 +1102,12 @@ static void WriteFileData(raw_ostream &OS, const MCFragment &F,
 /// WriteFileData - Write the \arg SD data to the output file.
 static void WriteFileData(raw_ostream &OS, const MCSectionData &SD,
                           MachObjectWriter &MOW) {
+  // Ignore virtual sections.
+  if (isVirtualSection(SD.getSection())) {
+    assert(SD.getFileSize() == 0);
+    return;
+  }
+
   uint64_t Start = OS.tell();
   (void) Start;
       
@@ -1078,12 +1123,16 @@ static void WriteFileData(raw_ostream &OS, const MCSectionData &SD,
 }
 
 void MCAssembler::Finish() {
-  // Layout the sections and fragments.
+  // Layout the concrete sections and fragments.
   uint64_t Address = 0;
   MCSectionData *Prev = 0;
   for (iterator it = begin(), ie = end(); it != ie; ++it) {
     MCSectionData &SD = *it;
 
+    // Skip virtual sections.
+    if (isVirtualSection(SD.getSection()))
+      continue;
+
     // Align this section if necessary by adding padding bytes to the previous
     // section.
     if (uint64_t Pad = OffsetToAlignment(Address, it->getAlignment())) {
@@ -1100,6 +1149,18 @@ void MCAssembler::Finish() {
     Prev = &SD;
   }
 
+  // Layout the virtual sections.
+  for (iterator it = begin(), ie = end(); it != ie; ++it) {
+    MCSectionData &SD = *it;
+
+    if (!isVirtualSection(SD.getSection()))
+      continue;
+
+    SD.setAddress(Address);
+    LayoutSection(SD);
+    Address += SD.getSize();
+  }
+
   // Write the object file.
   MachObjectWriter MOW(OS);
   MOW.WriteObject(*this);

lib/MC/MCMachOStreamer.cpp

@@ -278,7 +278,27 @@ void MCMachOStreamer::EmitCommonSymbol(MCSymbol *Symbol, unsigned Size,
 
 void MCMachOStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
                                    unsigned Size, unsigned Pow2Alignment) {
-  llvm_unreachable("FIXME: Not yet implemented!");
+  unsigned ByteAlignment = 1 << Pow2Alignment;
+  MCSectionData &SectData = getSectionData(*Section);
+
+  // The symbol may not be present, which only creates the section.
+  if (!Symbol)
+    return;
+
+  // FIXME: Assert that this section has the zerofill type.
+
+  assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
+
+  MCSymbolData &SD = getSymbolData(*Symbol);
+
+  MCFragment *F = new MCZeroFillFragment(Size, 1 << Pow2Alignment, &SectData);
+  SD.setFragment(F);
+
+  Symbol->setSection(*Section);
+
+  // Update the maximum alignment on the zero fill section if necessary.
+  if (ByteAlignment > SectData.getAlignment())
+    SectData.setAlignment(ByteAlignment);
 }
 
 void MCMachOStreamer::EmitBytes(const StringRef &Data) {

test/MC/MachO/lcomm-attributes.s

@@ -0,0 +1,136 @@
+// RUN: llvm-mc -triple i386-apple-darwin9 %s -filetype=obj -o - | macho-dump | FileCheck %s
+
+        // Note, this test intentionally mismatches Darwin 'as', which loses the
+	// following global marker.
+        //
+        // FIXME: We should probably warn about our interpretation of this.
+        .globl sym_lcomm_ext_A
+        .lcomm sym_lcomm_ext_A, 4
+        .lcomm sym_lcomm_ext_B, 4
+        .globl sym_lcomm_ext_B
+
+        .globl sym_zfill_ext_A
+        .zerofill __DATA, __bss, sym_zfill_ext_A, 4
+        .zerofill __DATA, __bss, sym_zfill_ext_B, 4
+        .globl sym_zfill_ext_B
+
+// CHECK: ('cputype', 7)
+// CHECK: ('cpusubtype', 3)
+// CHECK: ('filetype', 1)
+// CHECK: ('num_load_commands', 1)
+// CHECK: ('load_commands_size', 296)
+// CHECK: ('flag', 0)
+// CHECK: ('load_commands', [
+// CHECK:   # Load Command 0
+// CHECK:  (('command', 1)
+// CHECK:   ('size', 192)
+// CHECK:   ('segment_name', '\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:   ('vm_addr', 0)
+// CHECK:   ('vm_size', 16)
+// CHECK:   ('file_offset', 324)
+// CHECK:   ('file_size', 0)
+// CHECK:   ('maxprot', 7)
+// CHECK:   ('initprot', 7)
+// CHECK:   ('num_sections', 2)
+// CHECK:   ('flags', 0)
+// CHECK:   ('sections', [
+// CHECK:     # Section 0
+// CHECK:    (('section_name', '__text\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:     ('segment_name', '__TEXT\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:     ('address', 0)
+// CHECK:     ('size', 0)
+// CHECK:     ('offset', 324)
+// CHECK:     ('alignment', 0)
+// CHECK:     ('reloc_offset', 0)
+// CHECK:     ('num_reloc', 0)
+// CHECK:     ('flags', 0x80000000)
+// CHECK:     ('reserved1', 0)
+// CHECK:     ('reserved2', 0)
+// CHECK:    ),
+// CHECK:   ('_relocations', [
+// CHECK:   ])
+// CHECK:     # Section 1
+// CHECK:    (('section_name', '__bss\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:     ('segment_name', '__DATA\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:     ('address', 0)
+// CHECK:     ('size', 16)
+// CHECK:     ('offset', 0)
+// CHECK:     ('alignment', 0)
+// CHECK:     ('reloc_offset', 0)
+// CHECK:     ('num_reloc', 0)
+// CHECK:     ('flags', 0x1)
+// CHECK:     ('reserved1', 0)
+// CHECK:     ('reserved2', 0)
+// CHECK:    ),
+// CHECK:   ('_relocations', [
+// CHECK:   ])
+// CHECK:   ])
+// CHECK:  ),
+// CHECK:   # Load Command 1
+// CHECK:  (('command', 2)
+// CHECK:   ('size', 24)
+// CHECK:   ('symoff', 324)
+// CHECK:   ('nsyms', 4)
+// CHECK:   ('stroff', 372)
+// CHECK:   ('strsize', 68)
+// CHECK:   ('_string_data', '\x00sym_lcomm_ext_A\x00sym_lcomm_ext_B\x00sym_zfill_ext_A\x00sym_zfill_ext_B\x00\x00\x00\x00')
+// CHECK:   ('_symbols', [
+// CHECK:     # Symbol 0
+// CHECK:    (('n_strx', 1)
+// CHECK:     ('n_type', 0xf)
+// CHECK:     ('n_sect', 2)
+// CHECK:     ('n_desc', 0)
+// CHECK:     ('n_value', 0)
+// CHECK:     ('_string', 'sym_lcomm_ext_A')
+// CHECK:    ),
+// CHECK:     # Symbol 1
+// CHECK:    (('n_strx', 17)
+// CHECK:     ('n_type', 0xf)
+// CHECK:     ('n_sect', 2)
+// CHECK:     ('n_desc', 0)
+// CHECK:     ('n_value', 4)
+// CHECK:     ('_string', 'sym_lcomm_ext_B')
+// CHECK:    ),
+// CHECK:     # Symbol 2
+// CHECK:    (('n_strx', 33)
+// CHECK:     ('n_type', 0xf)
+// CHECK:     ('n_sect', 2)
+// CHECK:     ('n_desc', 0)
+// CHECK:     ('n_value', 8)
+// CHECK:     ('_string', 'sym_zfill_ext_A')
+// CHECK:    ),
+// CHECK:     # Symbol 3
+// CHECK:    (('n_strx', 49)
+// CHECK:     ('n_type', 0xf)
+// CHECK:     ('n_sect', 2)
+// CHECK:     ('n_desc', 0)
+// CHECK:     ('n_value', 12)
+// CHECK:     ('_string', 'sym_zfill_ext_B')
+// CHECK:    ),
+// CHECK:   ])
+// CHECK:  ),
+// CHECK:   # Load Command 2
+// CHECK:  (('command', 11)
+// CHECK:   ('size', 80)
+// CHECK:   ('ilocalsym', 0)
+// CHECK:   ('nlocalsym', 0)
+// CHECK:   ('iextdefsym', 0)
+// CHECK:   ('nextdefsym', 4)
+// CHECK:   ('iundefsym', 4)
+// CHECK:   ('nundefsym', 0)
+// CHECK:   ('tocoff', 0)
+// CHECK:   ('ntoc', 0)
+// CHECK:   ('modtaboff', 0)
+// CHECK:   ('nmodtab', 0)
+// CHECK:   ('extrefsymoff', 0)
+// CHECK:   ('nextrefsyms', 0)
+// CHECK:   ('indirectsymoff', 0)
+// CHECK:   ('nindirectsyms', 0)
+// CHECK:   ('extreloff', 0)
+// CHECK:   ('nextrel', 0)
+// CHECK:   ('locreloff', 0)
+// CHECK:   ('nlocrel', 0)
+// CHECK:   ('_indirect_symbols', [
+// CHECK:   ])
+// CHECK:  ),
+// CHECK: ])

test/MC/MachO/zerofill-1.s

@@ -0,0 +1,121 @@
+// RUN: llvm-mc -triple i386-apple-darwin9 %s -filetype=obj -o - | macho-dump --dump-section-data | FileCheck %s
+
+        .text
+        .byte 0                 // Align to 2**3 bytes, not 2**1
+        
+        .zerofill       __DATA, __common, zfill, 2, 1
+        
+        .data
+        .align 3
+
+// CHECK: ('cputype', 7)
+// CHECK: ('cpusubtype', 3)
+// CHECK: ('filetype', 1)
+// CHECK: ('num_load_commands', 1)
+// CHECK: ('load_commands_size', 364)
+// CHECK: ('flag', 0)
+// CHECK: ('load_commands', [
+// CHECK:   # Load Command 0
+// CHECK:  (('command', 1)
+// CHECK:   ('size', 260)
+// CHECK:   ('segment_name', '\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:   ('vm_addr', 0)
+// CHECK:   ('vm_size', 10)
+// CHECK:   ('file_offset', 392)
+// CHECK:   ('file_size', 8)
+// CHECK:   ('maxprot', 7)
+// CHECK:   ('initprot', 7)
+// CHECK:   ('num_sections', 3)
+// CHECK:   ('flags', 0)
+// CHECK:   ('sections', [
+// CHECK:     # Section 0
+// CHECK:    (('section_name', '__text\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:     ('segment_name', '__TEXT\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:     ('address', 0)
+// CHECK:     ('size', 1)
+// CHECK:     ('offset', 392)
+// CHECK:     ('alignment', 0)
+// CHECK:     ('reloc_offset', 0)
+// CHECK:     ('num_reloc', 0)
+// CHECK:     ('flags', 0x80000000)
+// CHECK:     ('reserved1', 0)
+// CHECK:     ('reserved2', 0)
+// CHECK:    ),
+// CHECK:   ('_relocations', [
+// CHECK:   ])
+// CHECK:     # Section 1
+// CHECK:    (('section_name', '__common\x00\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:     ('segment_name', '__DATA\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:     ('address', 8)
+// CHECK:     ('size', 2)
+// CHECK:     ('offset', 0)
+// CHECK:     ('alignment', 1)
+// CHECK:     ('reloc_offset', 0)
+// CHECK:     ('num_reloc', 0)
+// CHECK:     ('flags', 0x1)
+// CHECK:     ('reserved1', 0)
+// CHECK:     ('reserved2', 0)
+// CHECK:    ),
+// CHECK:   ('_relocations', [
+// CHECK:   ])
+// CHECK:     # Section 2
+// CHECK:    (('section_name', '__data\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:     ('segment_name', '__DATA\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:     ('address', 8)
+// CHECK:     ('size', 0)
+// CHECK:     ('offset', 400)
+// CHECK:     ('alignment', 3)
+// CHECK:     ('reloc_offset', 0)
+// CHECK:     ('num_reloc', 0)
+// CHECK:     ('flags', 0x0)
+// CHECK:     ('reserved1', 0)
+// CHECK:     ('reserved2', 0)
+// CHECK:    ),
+// CHECK:   ('_relocations', [
+// CHECK:   ])
+// CHECK:   ])
+// CHECK:  ),
+// CHECK:   # Load Command 1
+// CHECK:  (('command', 2)
+// CHECK:   ('size', 24)
+// CHECK:   ('symoff', 400)
+// CHECK:   ('nsyms', 1)
+// CHECK:   ('stroff', 412)
+// CHECK:   ('strsize', 8)
+// CHECK:   ('_string_data', '\x00zfill\x00\x00')
+// CHECK:   ('_symbols', [
+// CHECK:     # Symbol 0
+// CHECK:    (('n_strx', 1)
+// CHECK:     ('n_type', 0xe)
+// CHECK:     ('n_sect', 2)
+// CHECK:     ('n_desc', 0)
+// CHECK:     ('n_value', 8)
+// CHECK:     ('_string', 'zfill')
+// CHECK:    ),
+// CHECK:   ])
+// CHECK:  ),
+// CHECK:   # Load Command 2
+// CHECK:  (('command', 11)
+// CHECK:   ('size', 80)
+// CHECK:   ('ilocalsym', 0)
+// CHECK:   ('nlocalsym', 1)
+// CHECK:   ('iextdefsym', 1)
+// CHECK:   ('nextdefsym', 0)
+// CHECK:   ('iundefsym', 1)
+// CHECK:   ('nundefsym', 0)
+// CHECK:   ('tocoff', 0)
+// CHECK:   ('ntoc', 0)
+// CHECK:   ('modtaboff', 0)
+// CHECK:   ('nmodtab', 0)
+// CHECK:   ('extrefsymoff', 0)
+// CHECK:   ('nextrefsyms', 0)
+// CHECK:   ('indirectsymoff', 0)
+// CHECK:   ('nindirectsyms', 0)
+// CHECK:   ('extreloff', 0)
+// CHECK:   ('nextrel', 0)
+// CHECK:   ('locreloff', 0)
+// CHECK:   ('nlocrel', 0)
+// CHECK:   ('_indirect_symbols', [
+// CHECK:   ])
+// CHECK:  ),
+// CHECK: ])

test/MC/MachO/zerofill-2.s

@@ -0,0 +1,103 @@
+// RUN: llvm-mc -triple i386-apple-darwin9 %s -filetype=obj -o - | macho-dump --dump-section-data | FileCheck %s
+
+        .byte 0
+
+        // This file has size 2, the tail padding doesn't count.
+        .zerofill       __DATA, __bss, sym_a, 1
+
+// CHECK: ('cputype', 7)
+// CHECK: ('cpusubtype', 3)
+// CHECK: ('filetype', 1)
+// CHECK: ('num_load_commands', 1)
+// CHECK: ('load_commands_size', 296)
+// CHECK: ('flag', 0)
+// CHECK: ('load_commands', [
+// CHECK:   # Load Command 0
+// CHECK:  (('command', 1)
+// CHECK:   ('size', 192)
+// CHECK:   ('segment_name', '\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:   ('vm_addr', 0)
+// CHECK:   ('vm_size', 2)
+// CHECK:   ('file_offset', 324)
+// CHECK:   ('file_size', 1)
+// CHECK:   ('maxprot', 7)
+// CHECK:   ('initprot', 7)
+// CHECK:   ('num_sections', 2)
+// CHECK:   ('flags', 0)
+// CHECK:   ('sections', [
+// CHECK:     # Section 0
+// CHECK:    (('section_name', '__text\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:     ('segment_name', '__TEXT\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:     ('address', 0)
+// CHECK:     ('size', 1)
+// CHECK:     ('offset', 324)
+// CHECK:     ('alignment', 0)
+// CHECK:     ('reloc_offset', 0)
+// CHECK:     ('num_reloc', 0)
+// CHECK:     ('flags', 0x80000000)
+// CHECK:     ('reserved1', 0)
+// CHECK:     ('reserved2', 0)
+// CHECK:    ),
+// CHECK:   ('_relocations', [
+// CHECK:   ])
+// CHECK:     # Section 1
+// CHECK:    (('section_name', '__bss\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:     ('segment_name', '__DATA\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:     ('address', 1)
+// CHECK:     ('size', 1)
+// CHECK:     ('offset', 0)
+// CHECK:     ('alignment', 0)
+// CHECK:     ('reloc_offset', 0)
+// CHECK:     ('num_reloc', 0)
+// CHECK:     ('flags', 0x1)
+// CHECK:     ('reserved1', 0)
+// CHECK:     ('reserved2', 0)
+// CHECK:    ),
+// CHECK:   ('_relocations', [
+// CHECK:   ])
+// CHECK:   ])
+// CHECK:  ),
+// CHECK:   # Load Command 1
+// CHECK:  (('command', 2)
+// CHECK:   ('size', 24)
+// CHECK:   ('symoff', 328)
+// CHECK:   ('nsyms', 1)
+// CHECK:   ('stroff', 340)
+// CHECK:   ('strsize', 8)
+// CHECK:   ('_string_data', '\x00sym_a\x00\x00')
+// CHECK:   ('_symbols', [
+// CHECK:     # Symbol 0
+// CHECK:    (('n_strx', 1)
+// CHECK:     ('n_type', 0xe)
+// CHECK:     ('n_sect', 2)
+// CHECK:     ('n_desc', 0)
+// CHECK:     ('n_value', 1)
+// CHECK:     ('_string', 'sym_a')
+// CHECK:    ),
+// CHECK:   ])
+// CHECK:  ),
+// CHECK:   # Load Command 2
+// CHECK:  (('command', 11)
+// CHECK:   ('size', 80)
+// CHECK:   ('ilocalsym', 0)
+// CHECK:   ('nlocalsym', 1)
+// CHECK:   ('iextdefsym', 1)
+// CHECK:   ('nextdefsym', 0)
+// CHECK:   ('iundefsym', 1)
+// CHECK:   ('nundefsym', 0)
+// CHECK:   ('tocoff', 0)
+// CHECK:   ('ntoc', 0)
+// CHECK:   ('modtaboff', 0)
+// CHECK:   ('nmodtab', 0)
+// CHECK:   ('extrefsymoff', 0)
+// CHECK:   ('nextrefsyms', 0)
+// CHECK:   ('indirectsymoff', 0)
+// CHECK:   ('nindirectsyms', 0)
+// CHECK:   ('extreloff', 0)
+// CHECK:   ('nextrel', 0)
+// CHECK:   ('locreloff', 0)
+// CHECK:   ('nlocrel', 0)
+// CHECK:   ('_indirect_symbols', [
+// CHECK:   ])
+// CHECK:  ),
+// CHECK: ])

test/MC/MachO/zerofill-3.s

@@ -0,0 +1,141 @@
+// RUN: llvm-mc -triple i386-apple-darwin9 %s -filetype=obj -o - | macho-dump --dump-section-data | FileCheck %s
+
+        // FIXME: We don't get the order right currently, the assembler first
+        // orders the symbols, then assigns addresses. :(
+.if 0        
+        .lcomm          sym_lcomm_B, 4
+        .lcomm          sym_lcomm_C, 4, 4 
+        .lcomm          sym_lcomm_A, 4, 3
+        .lcomm          sym_lcomm_D, 4
+        .globl          sym_lcomm_D
+        .globl          sym_lcomm_C
+.else
+        .lcomm          sym_lcomm_C, 4, 4 
+        .lcomm          sym_lcomm_D, 4
+        .globl          sym_lcomm_D
+        .globl          sym_lcomm_C
+        
+        .lcomm          sym_lcomm_A, 4, 3
+        .lcomm          sym_lcomm_B, 4
+.endif
+
+// CHECK: ('cputype', 7)
+// CHECK: ('cpusubtype', 3)
+// CHECK: ('filetype', 1)
+// CHECK: ('num_load_commands', 1)
+// CHECK: ('load_commands_size', 296)
+// CHECK: ('flag', 0)
+// CHECK: ('load_commands', [
+// CHECK:   # Load Command 0
+// CHECK:  (('command', 1)
+// CHECK:   ('size', 192)
+// CHECK:   ('segment_name', '\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:   ('vm_addr', 0)
+// CHECK:   ('vm_size', 16)
+// CHECK:   ('file_offset', 324)
+// CHECK:   ('file_size', 0)
+// CHECK:   ('maxprot', 7)
+// CHECK:   ('initprot', 7)
+// CHECK:   ('num_sections', 2)
+// CHECK:   ('flags', 0)
+// CHECK:   ('sections', [
+// CHECK:     # Section 0
+// CHECK:    (('section_name', '__text\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:     ('segment_name', '__TEXT\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:     ('address', 0)
+// CHECK:     ('size', 0)
+// CHECK:     ('offset', 324)
+// CHECK:     ('alignment', 0)
+// CHECK:     ('reloc_offset', 0)
+// CHECK:     ('num_reloc', 0)
+// CHECK:     ('flags', 0x80000000)
+// CHECK:     ('reserved1', 0)
+// CHECK:     ('reserved2', 0)
+// CHECK:    ),
+// CHECK:   ('_relocations', [
+// CHECK:   ])
+// CHECK:     # Section 1
+// CHECK:    (('section_name', '__bss\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:     ('segment_name', '__DATA\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:     ('address', 0)
+// CHECK:     ('size', 16)
+// CHECK:     ('offset', 0)
+// CHECK:     ('alignment', 4)
+// CHECK:     ('reloc_offset', 0)
+// CHECK:     ('num_reloc', 0)
+// CHECK:     ('flags', 0x1)
+// CHECK:     ('reserved1', 0)
+// CHECK:     ('reserved2', 0)
+// CHECK:    ),
+// CHECK:   ('_relocations', [
+// CHECK:   ])
+// CHECK:   ])
+// CHECK:  ),
+// CHECK:   # Load Command 1
+// CHECK:  (('command', 2)
+// CHECK:   ('size', 24)
+// CHECK:   ('symoff', 324)
+// CHECK:   ('nsyms', 4)
+// CHECK:   ('stroff', 372)
+// CHECK:   ('strsize', 52)
+// CHECK:   ('_string_data', '\x00sym_lcomm_C\x00sym_lcomm_D\x00sym_lcomm_A\x00sym_lcomm_B\x00\x00\x00\x00')
+// CHECK:   ('_symbols', [
+// CHECK:     # Symbol 0
+// CHECK:    (('n_strx', 25)
+// CHECK:     ('n_type', 0xe)
+// CHECK:     ('n_sect', 2)
+// CHECK:     ('n_desc', 0)
+// CHECK:     ('n_value', 8)
+// CHECK:     ('_string', 'sym_lcomm_A')
+// CHECK:    ),
+// CHECK:     # Symbol 1
+// CHECK:    (('n_strx', 37)
+// CHECK:     ('n_type', 0xe)
+// CHECK:     ('n_sect', 2)
+// CHECK:     ('n_desc', 0)
+// CHECK:     ('n_value', 12)
+// CHECK:     ('_string', 'sym_lcomm_B')
+// CHECK:    ),
+// CHECK:     # Symbol 2
+// CHECK:    (('n_strx', 1)
+// CHECK:     ('n_type', 0xf)
+// CHECK:     ('n_sect', 2)
+// CHECK:     ('n_desc', 0)
+// CHECK:     ('n_value', 0)
+// CHECK:     ('_string', 'sym_lcomm_C')
+// CHECK:    ),
+// CHECK:     # Symbol 3
+// CHECK:    (('n_strx', 13)
+// CHECK:     ('n_type', 0xf)
+// CHECK:     ('n_sect', 2)
+// CHECK:     ('n_desc', 0)
+// CHECK:     ('n_value', 4)
+// CHECK:     ('_string', 'sym_lcomm_D')
+// CHECK:    ),
+// CHECK:   ])
+// CHECK:  ),
+// CHECK:   # Load Command 2
+// CHECK:  (('command', 11)
+// CHECK:   ('size', 80)
+// CHECK:   ('ilocalsym', 0)
+// CHECK:   ('nlocalsym', 2)
+// CHECK:   ('iextdefsym', 2)
+// CHECK:   ('nextdefsym', 2)
+// CHECK:   ('iundefsym', 4)
+// CHECK:   ('nundefsym', 0)
+// CHECK:   ('tocoff', 0)
+// CHECK:   ('ntoc', 0)
+// CHECK:   ('modtaboff', 0)
+// CHECK:   ('nmodtab', 0)
+// CHECK:   ('extrefsymoff', 0)
+// CHECK:   ('nextrefsyms', 0)
+// CHECK:   ('indirectsymoff', 0)
+// CHECK:   ('nindirectsyms', 0)
+// CHECK:   ('extreloff', 0)
+// CHECK:   ('nextrel', 0)
+// CHECK:   ('locreloff', 0)
+// CHECK:   ('nlocrel', 0)
+// CHECK:   ('_indirect_symbols', [
+// CHECK:   ])
+// CHECK:  ),
+// CHECK: ])