[XCOFF][AIX] Fix incorrect alignment for function descriptor csect

Summary:
Function descriptor csect on AIX should be 4 byte align instead of 1 byte align.

Reviewer: daltenty

Differential Revision: https://reviews.llvm.org/D74974

Author: jasonliudev

llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp

@@ -1547,9 +1547,10 @@ void PPCLinuxAsmPrinter::emitFunctionBodyEnd() {
 void PPCAIXAsmPrinter::SetupMachineFunction(MachineFunction &MF) {
   // Get the function descriptor symbol.
   CurrentFnDescSym = getSymbol(&MF.getFunction());
-  // Set the containing csect.
+  // Set the alignment and the containing csect.
   MCSectionXCOFF *FnDescSec = cast<MCSectionXCOFF>(
       getObjFileLowering().getSectionForFunctionDescriptor(CurrentFnDescSym));
+  FnDescSec->setAlignment(Align(Subtarget->isPPC64() ? 8 : 4));
   cast<MCSymbolXCOFF>(CurrentFnDescSym)->setContainingCsect(FnDescSec);
 
   return AsmPrinter::SetupMachineFunction(MF);

llvm/test/CodeGen/PowerPC/aix-func-dsc-gen.ll

@@ -63,7 +63,7 @@ entry:
 ; CHECK-NEXT:       SectionLen: 12
 ; CHECK-NEXT:       ParameterHashIndex: 0x0
 ; CHECK-NEXT:       TypeChkSectNum: 0x0
-; CHECK-NEXT:       SymbolAlignmentLog2: 0
+; CHECK-NEXT:       SymbolAlignmentLog2: 2
 ; CHECK-NEXT:       SymbolType: XTY_SD (0x1)
 ; CHECK-NEXT:       StorageMappingClass: XMC_DS (0xA)
 ; CHECK-NEXT:       StabInfoIndex: 0x0

llvm/test/CodeGen/PowerPC/aix-xcoff-reloc.ll

@@ -318,7 +318,7 @@ declare i32 @bar(i32)
 ; SYM-NEXT:       SectionLen: 12
 ; SYM-NEXT:       ParameterHashIndex: 0x0
 ; SYM-NEXT:       TypeChkSectNum: 0x0
-; SYM-NEXT:       SymbolAlignmentLog2: 0
+; SYM-NEXT:       SymbolAlignmentLog2: 2
 ; SYM-NEXT:       SymbolType: XTY_SD (0x1)
 ; SYM-NEXT:       StorageMappingClass: XMC_DS (0xA)
 ; SYM-NEXT:       StabInfoIndex: 0x0