Revert "MC: Allocate initial fragment and define section symbol in changeSection" (#150736)

Reverts llvm/llvm-project#150574

This is causing a test failure on AArch64 MacOS bots:
https://lab.llvm.org/buildbot/#/builders/190/builds/24187

1 files changed, 8 insertions, 4 deletions

diff --git a/llvm/lib/MC/MCStreamer.cpp b/llvm/lib/MC/MCStreamer.cpp
index 899a7df..e14a32f5 100644
--- a/llvm/lib/MC/MCStreamer.cpp
+++ b/llvm/lib/MC/MCStreamer.cpp
@@ -1314,10 +1314,8 @@ void MCStreamer::emitZerofill(MCSection *, MCSymbol *, uint64_t, Align, SMLoc) {
 }
 void MCStreamer::emitTBSSSymbol(MCSection *Section, MCSymbol *Symbol,
                                 uint64_t Size, Align ByteAlignment) {}
-void MCStreamer::changeSection(MCSection *Sec, uint32_t) {
-  CurFrag = &Sec->getDummyFragment();
-  if (auto *Sym = Sec->getBeginSymbol())
-    Sym->setFragment(&Sec->getDummyFragment());
+void MCStreamer::changeSection(MCSection *Section, uint32_t) {
+  CurFrag = &Section->getDummyFragment();
 }
 void MCStreamer::emitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) {}
 void MCStreamer::emitBytes(StringRef Data) {}
@@ -1360,6 +1358,9 @@ void MCStreamer::switchSection(MCSection *Section, uint32_t Subsection) {
     changeSection(Section, Subsection);
     SectionStack.back().first = MCSectionSubPair(Section, Subsection);
     assert(!Section->hasEnded() && "Section already ended");
+    MCSymbol *Sym = Section->getBeginSymbol();
+    if (Sym && !Sym->isInSection())
+      emitLabel(Sym);
   }
 }
 
@@ -1386,6 +1387,9 @@ void MCStreamer::switchSectionNoPrint(MCSection *Section) {
   SectionStack.back().second = SectionStack.back().first;
   SectionStack.back().first = MCSectionSubPair(Section, 0);
   changeSection(Section, 0);
+  MCSymbol *Sym = Section->getBeginSymbol();
+  if (Sym && !Sym->isInSection())
+    emitLabel(Sym);
 }
 
 MCSymbol *MCStreamer::endSection(MCSection *Section) {