[MC] Add MCFragment allocation helpers

`allocFragment` might be changed to a placement new when the allocation
strategy changes.

`allocInitialFragment` is to deduplicate the following pattern
```
  auto *F = new MCDataFragment();
  Result->addFragment(*F);
  F->setParent(Result);
```

Pull Request: https://github.com/llvm/llvm-project/pull/95197

1 files changed, 7 insertions, 3 deletions

diff --git a/llvm/lib/MC/MCMachOStreamer.cpp b/llvm/lib/MC/MCMachOStreamer.cpp
index 466aa63..6b2e411 100644
--- a/llvm/lib/MC/MCMachOStreamer.cpp
+++ b/llvm/lib/MC/MCMachOStreamer.cpp
@@ -199,7 +199,7 @@ void MCMachOStreamer::emitLabel(MCSymbol *Symbol, SMLoc Loc) {
   // We have to create a new fragment if this is an atom defining symbol,
   // fragments cannot span atoms.
   if (getAssembler().isSymbolLinkerVisible(*Symbol))
-    insert(new MCDataFragment());
+    insert(getContext().allocFragment<MCDataFragment>());
 
   MCObjectStreamer::emitLabel(Symbol, Loc);
 
@@ -555,7 +555,9 @@ void MCMachOStreamer::finalizeCGProfile() {
   MCSection *CGProfileSection = Asm.getContext().getMachOSection(
       "__LLVM", "__cg_profile", 0, SectionKind::getMetadata());
   Asm.registerSection(*CGProfileSection);
-  auto *Frag = new MCDataFragment(CGProfileSection);
+  auto *Frag = getContext().allocFragment<MCDataFragment>();
+  Frag->setParent(CGProfileSection);
+  CGProfileSection->addFragment(*Frag);
   // For each entry, reserve space for 2 32-bit indices and a 64-bit count.
   size_t SectionBytes =
       Asm.CGProfile.size() * (2 * sizeof(uint32_t) + sizeof(uint64_t));
@@ -595,7 +597,9 @@ void MCMachOStreamer::createAddrSigSection() {
   MCSection *AddrSigSection =
       Asm.getContext().getObjectFileInfo()->getAddrSigSection();
   Asm.registerSection(*AddrSigSection);
-  auto *Frag = new MCDataFragment(AddrSigSection);
+  auto *Frag = getContext().allocFragment<MCDataFragment>();
+  Frag->setParent(AddrSigSection);
+  AddrSigSection->addFragment(*Frag);
   // We will generate a series of pointer-sized symbol relocations at offset
   // 0x0. Set the section size to be large enough to contain a single pointer
   // (instead of emitting a zero-sized section) so these relocations are