[lld] Partially revert "Always emit symbol table when dwarf section exists in COFF"

This reverts part of commit 44363f2.

Fixup for NO symbol table test has been reserved.

Reviewed By: wxiao3

Differential Revision: https://reviews.llvm.org/D151417

Author: HaohaiWen

lld/COFF/Writer.cpp

@@ -1266,9 +1266,7 @@ void Writer::createSymbolAndStringTable() {
   // solution where discardable sections have long names preserved and
   // non-discardable sections have their names truncated, to ensure that any
   // section which is mapped at runtime also has its name mapped at runtime.
-  bool HasDwarfSection = false;
   for (OutputSection *sec : ctx.outputSections) {
-    HasDwarfSection |= sec->name.startswith(".debug_");
     if (sec->name.size() <= COFF::NameSize)
       continue;
     if ((sec->header.Characteristics & IMAGE_SCN_MEM_DISCARDABLE) == 0)
@@ -1281,7 +1279,7 @@ void Writer::createSymbolAndStringTable() {
     sec->setStringTableOff(addEntryToStringTable(sec->name));
   }
 
-  if (ctx.config.debugDwarf || ctx.config.debugSymtab || HasDwarfSection) {
+  if (ctx.config.debugDwarf || ctx.config.debugSymtab) {
     for (ObjFile *file : ctx.objFileInstances) {
       for (Symbol *b : file->getSymbols()) {
         auto *d = dyn_cast_or_null<Defined>(b);

lld/test/COFF/symtab.test

@@ -8,8 +8,6 @@
 
 # RUN: lld-link /debug /out:%t.exe /entry:main %t.obj %p/Inputs/std64.lib
 # RUN: llvm-readobj --symbols %t.exe | FileCheck -check-prefix=NO %s
-# RUN: lld-link /debug /merge:.blank=.debug_info /out:%t.exe /entry:main %t.obj %p/Inputs/std64.lib
-# RUN: llvm-readobj --symbols %t.exe | FileCheck %s
 
 # CHECK:      Symbols [
 # CHECK-NEXT:   Symbol {
@@ -144,10 +142,6 @@ sections:
     Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ, IMAGE_SCN_MEM_WRITE ]
     Alignment:       4
     SectionData:     48656C6C6F0048656C6C6F20576F726C6400
-  - Name:            .blank
-    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_DISCARDABLE, IMAGE_SCN_MEM_READ ]
-    Alignment:       1
-    SectionData:     0000
 symbols:
   - Name:            "@comp.id"
     Value:           10394907