[lld-macho][nfc] Move list of section names into InputSection.h

[int3]

Summary

They were previously in SyntheticSections.h, but now there are
a bunch of non-synthetic section names in the list.

Also renamed __functionStarts to __func_starts for uniformity with
other section names + keeps the name under 16 characters (in case we ever
want to write it out as a real section).

[compnerd]

I don't think that LC_FUNCTION_STARTS would create an actual section.

[int3]

I think ld64 has the option of emitting section headers for all hidden sections, probably for debugging purposes. LLD doesn't support that at the moment though

lld/MachO/InputSection.h

inline bool isDebugSection(uint32_t flags) {
   return (flags & llvm::MachO::SECTION_ATTRIBUTES_USR) ==
          llvm::MachO::S_ATTR_DEBUG;
 }
 
 bool isCodeSection(InputSection *);
 
 extern std::vector<InputSection *> inputSections;
 
+namespace section_names {
+
+constexpr const char pageZero[] = "__pagezero";
+constexpr const char common[] = "__common";
+constexpr const char header[] = "__mach_header";
+constexpr const char rebase[] = "__rebase";
+constexpr const char binding[] = "__binding";
+constexpr const char weakBinding[] = "__weak_binding";
+constexpr const char lazyBinding[] = "__lazy_binding";
+constexpr const char export_[] = "__export";
+constexpr const char functionStarts[] = "__func_starts";
+constexpr const char symbolTable[] = "__symbol_table";
+constexpr const char indirectSymbolTable[] = "__ind_sym_tab";
+constexpr const char stringTable[] = "__string_table";
+constexpr const char codeSignature[] = "__code_signature";
+constexpr const char got[] = "__got";
+constexpr const char threadPtrs[] = "__thread_ptrs";
+constexpr const char unwindInfo[] = "__unwind_info";
+constexpr const char compactUnwind[] = "__compact_unwind";
+constexpr const char ehFrame[] = "__eh_frame";
+constexpr const char text[] = "__text";
+constexpr const char stubs[] = "__stubs";
+constexpr const char stubHelper[] = "__stub_helper";
+constexpr const char laSymbolPtr[] = "__la_symbol_ptr";
+constexpr const char data[] = "__data";
+
+} // namespace section_names
+
 } // namespace macho
 
 std::string toString(const macho::InputSection *);
 
 } // namespace lld
 
 #endif

lld/MachO/SyntheticSections.h

 
 namespace llvm {
 class DWARFUnit;
 } // namespace llvm
 
 namespace lld {
 namespace macho {
 
-namespace section_names {
-
-constexpr const char pageZero[] = "__pagezero";
-constexpr const char common[] = "__common";
-constexpr const char header[] = "__mach_header";
-constexpr const char rebase[] = "__rebase";
-constexpr const char binding[] = "__binding";
-constexpr const char weakBinding[] = "__weak_binding";
-constexpr const char lazyBinding[] = "__lazy_binding";
-constexpr const char export_[] = "__export";
-constexpr const char functionStarts_[] = "__functionStarts";
-constexpr const char symbolTable[] = "__symbol_table";
-constexpr const char indirectSymbolTable[] = "__ind_sym_tab";
-constexpr const char stringTable[] = "__string_table";
-constexpr const char codeSignature[] = "__code_signature";
-constexpr const char got[] = "__got";
-constexpr const char threadPtrs[] = "__thread_ptrs";
-constexpr const char unwindInfo[] = "__unwind_info";
-// these are not synthetic, but in service of synthetic __unwind_info
-constexpr const char compactUnwind[] = "__compact_unwind";
-constexpr const char ehFrame[] = "__eh_frame";
-// these are not synthetic, but need to be sorted
-constexpr const char text[] = "__text";
-constexpr const char stubs[] = "__stubs";
-constexpr const char stubHelper[] = "__stub_helper";
-constexpr const char laSymbolPtr[] = "__la_symbol_ptr";
-constexpr const char data[] = "__data";
-
-} // namespace section_names
-
 class Defined;
 class DylibSymbol;
 class LoadCommand;
 class ObjFile;
 
 class SyntheticSection : public OutputSection {
 public:
   SyntheticSection(const char *segname, const char *name);

lld/MachO/SyntheticSections.cpp

for (const Symbol *sym : symtab->getSymbols()) {
     }
   }
   size = trieBuilder.build();
 }
 
 void ExportSection::writeTo(uint8_t *buf) const { trieBuilder.writeTo(buf); }
 
 FunctionStartsSection::FunctionStartsSection()
-    : LinkEditSection(segment_names::linkEdit, section_names::functionStarts_) {
-}
+    : LinkEditSection(segment_names::linkEdit, section_names::functionStarts) {}
 
 void FunctionStartsSection::finalizeContents() {
   raw_svector_ostream os{contents};
   uint64_t addr = in.header->addr;
   for (const Symbol *sym : symtab->getSymbols()) {
     if (const auto *defined = dyn_cast<Defined>(sym)) {
       if (!defined->isec || !isCodeSection(defined->isec))
         continue;