[lld][WebAssembly][NFC] Move getOutputSegmentName to InputChunk methods

[kateinoigakukun]

Summary

This patch is extracted from the https://reviews.llvm.org/D126950.
It renames getOutputDataSegmentName static function to getOutputSegmentName, and also place it in InputChunk to reuse it while GCing sections.

[sbc100]

lld/wasm/InputChunks.cpp

531

Actually, looking at this code and looking at how ELF does this.. I think you can just use getName in the other patch and maybe this patch is not actually needed?

None of these combined segments return true for isValidCIdentifier so I think you can just to what ELF in its MakeLive.cpp and use the intput section name.

[kateinoigakukun]

lld/wasm/InputChunks.cpp

531

Ah, it makes sense to me.

[sbc100]

I guess we can abandon this?

lld/wasm/InputChunks.h

public:
   // the parent merged chunk.  For other chunk types this is no-op and we just
   // return unmodified offset.
   uint64_t getChunkOffset(uint64_t offset) const;
   uint64_t getVA(uint64_t offset = 0) const;
 
   uint32_t getComdat() const { return comdat; }
   StringRef getComdatName() const;
   uint32_t getInputSectionOffset() const { return inputSectionOffset; }
+  StringRef getOutputSegmentName() const;
 
   size_t getNumRelocations() const { return relocations.size(); }
   void writeRelocations(llvm::raw_ostream &os) const;
   void generateRelocationCode(raw_ostream &os) const;
 
   bool isTLS() const { return flags & llvm::wasm::WASM_SEG_FLAG_TLS; }
 
   ObjFile *file;

lld/wasm/InputChunks.cpp

uint64_t InputSection::getTombstoneForSection(StringRef name) {
   // will just use the addend.
   if (!name.startswith(".debug_"))
     return 0;
   if (name.equals(".debug_ranges") || name.equals(".debug_loc"))
     return UINT64_C(-2);
   return UINT64_C(-1);
 }
 
+StringRef InputChunk::getOutputSegmentName() const {
+  // We always merge .tbss and .tdata into a single TLS segment so all TLS
+  // symbols are be relative to single __tls_base.
+  if (isTLS())
+    return ".tdata";
+  StringRef name = getName();
+  if (!config->mergeDataSegments)
+    return name;
+  if (name.startswith(".text."))
+    return ".text";
+  if (name.startswith(".data."))
+    return ".data";
+  if (name.startswith(".bss."))
+    return ".bss";
+  if (name.startswith(".rodata."))
+    return ".rodata";
+  return name;
+}
+
 } // namespace wasm
 } // namespace lld

lld/wasm/Writer.cpp

void Writer::assignIndexes() {
 
   for (InputTable *table : symtab->syntheticTables)
     out.tableSec->addTable(table);
 
   out.globalSec->assignIndexes();
   out.tableSec->assignIndexes();
 }
 
-static StringRef getOutputDataSegmentName(const InputChunk &seg) {
-  // We always merge .tbss and .tdata into a single TLS segment so all TLS
-  // symbols are be relative to single __tls_base.
-  if (seg.isTLS())
-    return ".tdata";
-  StringRef name = seg.getName();
-  if (!config->mergeDataSegments)
-    return name;
-  if (name.startswith(".text."))
-    return ".text";
-  if (name.startswith(".data."))
-    return ".data";
-  if (name.startswith(".bss."))
-    return ".bss";
-  if (name.startswith(".rodata."))
-    return ".rodata";
-  return name;
-}
-
 OutputSegment *Writer::createOutputSegment(StringRef name) {
   LLVM_DEBUG(dbgs() << "new segment: " << name << "\n");
   OutputSegment *s = make<OutputSegment>(name);
   if (config->sharedMemory)
     s->initFlags = WASM_DATA_SEGMENT_IS_PASSIVE;
   if (!config->relocatable && name.startswith(".bss"))
     s->isBss = true;
   segments.push_back(s);
   return s;
 }
 
 void Writer::createOutputSegments() {
   for (ObjFile *file : symtab->objectFiles) {
     for (InputChunk *segment : file->segments) {
       if (!segment->live)
         continue;
-      StringRef name = getOutputDataSegmentName(*segment);
+      StringRef name = segment->getOutputSegmentName();
       OutputSegment *s = nullptr;
       // When running in relocatable mode we can't merge segments that are part
       // of comdat groups since the ultimate linker needs to be able exclude or
       // include them individually.
       if (config->relocatable && !segment->getComdatName().empty()) {
         s = createOutputSegment(name);
       } else {
         if (segmentMap.count(name) == 0)