[AMDGPU] Don’t marke the .note section as ALLOC

[Flakebi]

Summary

Marking a section as ALLOC tells the ELF loader to load the section into memory.
As we do not want to load the notes into VRAM, the flag should not be there.

[arsenm]

Needs test

[Flakebi]

Fix test, I hope the existing test suffices.

I thought about adding a test that checks that the code section is the only section with flags != 0
but this won’t hold when a data section or others get used.

[nhaehnle]

LGTM

llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUTargetStreamer.cpp

void AMDGPUTargetELFStreamer::EmitNote(
     function_ref<void(MCELFStreamer &)> EmitDesc) {
   auto &S = getStreamer();
   auto &Context = S.getContext();
 
   auto NameSZ = Name.size() + 1;
 
   S.PushSection();
   S.SwitchSection(Context.getELFSection(
-    ElfNote::SectionName, ELF::SHT_NOTE, ELF::SHF_ALLOC));
+    ElfNote::SectionName, ELF::SHT_NOTE, 0));
   S.emitIntValue(NameSZ, 4);                                  // namesz
   S.emitValue(DescSZ, 4);                                     // descz
   S.emitIntValue(NoteType, 4);                                // type
   S.emitBytes(Name);                                          // name
   S.emitValueToAlignment(4, 0, 1, 0);                         // padding 0
   EmitDesc(S);                                                // desc
   S.emitValueToAlignment(4, 0, 1, 0);                         // padding 0
   S.PopSection();

llvm/test/CodeGen/AMDGPU/hsa.ll

 ; ELF: Name: .text
 ; ELF: Type: SHT_PROGBITS (0x1)
 ; ELF: Flags [ (0x6)
 ; ELF: SHF_ALLOC (0x2)
 ; ELF: SHF_EXECINSTR (0x4)
 ; ELF: }
 
 ; ELF: SHT_NOTE
-; ELF: Flags [ (0x2)
-; ELF: SHF_ALLOC (0x2)
+; ELF: Flags [ (0x0)
 ; ELF: ]
 ; ELF: SectionData (
 ; ELF: 0000: 04000000 08000000 01000000 414D4400
 ; ELF: 0010: 02000000 01000000 04000000 1B000000
 ; ELF: 0020: 03000000 414D4400 04000700 07000000
 ; ELF: 0030: 00000000 00000000 414D4400 414D4447
 ; ELF: 0040: 50550000
 ; ELF: )