[lld-macho] Ensure .tbss sections are also considered as ZeroFilled

[int3]

Summary

This diff makes the behavior in D80859: [lld-macho] Ensure __bss sections we output have file offset of zero and D81888: [lld-macho] Make sure ZeroFill sections are at the end of their segments apply to
thread-local ZeroFill sections too. I realized this was necessary whie
trying to implement thread-local variables.

[MaskRay]

Looks great!

lld/MachO/InputSection.h

39

If you using namespace llvm then you can omit llvm::

[int3]

lld/MachO/InputSection.h

39

I think we should avoid using namespace inside header files...

[MaskRay]

lld/MachO/InputSection.h

39

You're right. Did not notice this is a .h......... my bad

lld/MachO/InputSection.h

struct Reloc {
   uint32_t offset;
   // Adding this offset to the address of the target symbol or subsection gives
   // the destination that this relocation refers to.
   uint64_t addend;
   llvm::PointerUnion<Symbol *, InputSection *> target;
 };
 
 inline bool isZeroFill(uint8_t flags) {
-  return (flags & llvm::MachO::SECTION_TYPE) == llvm::MachO::S_ZEROFILL;
+  return llvm::MachO::isVirtualSection(flags & llvm::MachO::SECTION_TYPE);
+}
 }
 
 class InputSection {
 public:
   virtual ~InputSection() = default;
   virtual uint64_t getSize() const { return data.size(); }
   virtual uint64_t getFileSize() const {
     return isZeroFill(flags) ? 0 : getSize();
   }
   uint64_t getFileOffset() const;
   uint64_t getVA() const;
 
   virtual void writeTo(uint8_t *buf);
 
   InputFile *file = nullptr;
   StringRef name;
   StringRef segname;
 
   OutputSection *parent = nullptr;
   uint64_t outSecOff = 0;
   uint64_t outSecFileOff = 0;
 
   uint32_t align = 1;
   uint32_t flags = 0;
 
   ArrayRef<uint8_t> data;
   std::vector<Reloc> relocs;
 };
 
 extern std::vector<InputSection *> inputSections;
 
 } // namespace macho
 } // namespace lld
 
 #endif

lld/test/MachO/bss.s

 # CHECK-NEXT:   Reserved1: 0x0
 # CHECK-NEXT:   Reserved2: 0x0
 # CHECK-NEXT:   Reserved3: 0x0
 
 # CHECK:        Index: 2
 # CHECK-NEXT:   Name: __bss
 # CHECK-NEXT:   Segment: __DATA
 # CHECK-NEXT:   Address:
-# CHECK-NEXT:   Size: 0x4
+# CHECK-NEXT:   Size: 0x8
 # CHECK-NEXT:   Offset: 0
 # CHECK-NEXT:   Alignment: 0
 # CHECK-NEXT:   RelocationOffset: 0x0
 # CHECK-NEXT:   RelocationCount: 0
 # CHECK-NEXT:   Type: ZeroFill (0x1)
 # CHECK-NEXT:   Attributes [ (0x0)
 # CHECK-NEXT:   ]
 # CHECK-NEXT:   Reserved1: 0x0
 # CHECK-NEXT:   Reserved2: 0x0
 # CHECK-NEXT:   Reserved3: 0x0
 
+# CHECK:        Index: 3
+# CHECK-NEXT:   Name: __thread_bss
+# CHECK-NEXT:   Segment: __DATA
+# CHECK-NEXT:   Address: 0x100001010
+# CHECK-NEXT:   Size: 0x4
+# CHECK-NEXT:   Offset: 0
+# CHECK-NEXT:   Alignment: 0
+# CHECK-NEXT:   RelocationOffset: 0x0
+# CHECK-NEXT:   RelocationCount: 0
+# CHECK-NEXT:   Type: ThreadLocalZerofill (0x12)
+# CHECK-NEXT:   Attributes [ (0x0)
+# CHECK-NEXT:   ]
+# CHECK-NEXT:   Reserved1: 0x0
+# CHECK-NEXT:   Reserved2: 0x0
+# CHECK-NEXT:   Reserved3: 0x0
+
 # CHECK:      Name: __DATA
 # CHECK-NEXT: Size:
 # CHECK-NEXT: vmaddr:
-# CHECK-NEXT: vmsize: 0xC
+# CHECK-NEXT: vmsize: 0x14
 # CHECK-NEXT: fileoff:
 # CHECK-NEXT: filesize: 8
 
 .globl _main
 
 .text
 _main:
   movq $0, %rax
   retq
 
 .bss
 .zero 4
 
+.tbss _foo, 4
+.zero 4
+
 .data
 .quad 0x1234