[PowerPC][XCOFF] Add assembly support for zero initalized global values.

[jasonliu]

This patch is going to have conflict with D67125. Depending on which patch is going to go land first, the test case is likely need to get modified.

I would propose to let D67125 be the parent and add object file generation test in this patch.

[sfertile]

In D69528#1724277, @jasonliu wrote:

This patch is going to have conflict with D67125. Depending on which patch is going to go land first, the test case is likely need to get modified.

I would propose to let D67125 be the parent and add object file generation test in this patch.

Sure. That is pretty reasonable.

[sfertile]

Rebased to pick up test changes from D67125

[daltenty]

LGTM

[DiggerLin]

LGTM

[DiggerLin]

llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp

1861

how about the Kind.isBSSExternal() ?

[DiggerLin]

llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp

1861

I read the code again, the Kind.isBSS() include the BSSExternal
bool isBSS() const { return K == BSS || K == BSSLocal || K == BSSExtern; }

[DiggerLin]

llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp

1861

The BSSLocal will be put in the .bss section.

Here I think it maybe better(more clear) to change to
if (Kind.isBSS() && !kind.isBSSLocal())

keep current code, it is OK, for the code in the line 1842 , it deal with the Kind.isBSSLocal() first before it go to line 1861.
if (Kind.isBSSLocal() || Kind.isCommon()) {

[xingxue]

Test file aix-xcoff-data.ll needs a rebase.

llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp

MCSection *TargetLoweringObjectFileXCOFF::SelectSectionForGlobal(
   }
 
   if (Kind.isText())
     return TextSection;
 
   if (Kind.isData())
     return DataSection;
 
+  // Zero initialized data must be emitted to the .data section because external
+  // linkage control sections that get mapped to the .bss section will be linked
+  // as tentative defintions, which is only appropriate for SectionKind::Common.
+  if (Kind.isBSS())
+    return DataSection;
+
   report_fatal_error("XCOFF other section types not yet implemented.");
 }
 
 bool TargetLoweringObjectFileXCOFF::shouldPutJumpTableInFunctionSection(
     bool UsesLabelDifference, const Function &F) const {
   report_fatal_error("TLOF XCOFF not yet implemented.");
 }
 

llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp

void PPCAIXAsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
 
   if (GV->hasSection())
     report_fatal_error("Custom section for Data not yet supported.");
 
   if (GV->hasComdat())
     report_fatal_error("COMDAT not yet supported by AIX.");
 
   SectionKind GVKind = getObjFileLowering().getKindForGlobal(GV, TM);
-  if (!GVKind.isCommon() && !GVKind.isBSSLocal() && !GVKind.isData())
+  if (!GVKind.isCommon() && !GVKind.isBSS() && !GVKind.isData())
     report_fatal_error("Encountered a global variable kind that is "
                        "not supported yet.");
 
   // Create the containing csect and switch to it.
   MCSectionXCOFF *CSect = cast<MCSectionXCOFF>(
       getObjFileLowering().SectionForGlobal(GV, GVKind, TM));
   OutStreamer->SwitchSection(CSect);
 

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

 @ivar = local_unnamed_addr global i32 35, align 4
 @llvar = local_unnamed_addr global i64 36, align 8
 @svar = local_unnamed_addr global i16 37, align 2
 @fvar = local_unnamed_addr global float 8.000000e+02, align 4
 @dvar = local_unnamed_addr global double 9.000000e+02, align 8
 @over_aligned = local_unnamed_addr global double 9.000000e+02, align 32
 @chrarray = local_unnamed_addr global [4 x i8] c"abcd", align 1
 @dblarr = local_unnamed_addr global [4 x double] [double 1.000000e+00, double 2.000000e+00, double 3.000000e+00, double 4.000000e+00], align 8
+@d_0 = global double 0.000000e+00, align 8
+@s_0 = global i16 0, align 2
+@f_0 = global float 0.000000e+00, align 4
 
 @a = common global i32 0, align 4
 @b = common global i64 0, align 8
 @c = common global i16 0, align 2
 
 ; CHECK:      .csect .data[RW]
 ; CHECK-NEXT: .globl  ivar
 ; CHECK-NEXT: .align  2

 ; CHECK:      .globl  dblarr
 ; CHECK-NEXT: .align  3
 ; CHECK-NEXT: dblarr:
 ; CHECK-NEXT: .llong  4607182418800017408
 ; CHECK-NEXT: .llong  4611686018427387904
 ; CHECK-NEXT: .llong  4613937818241073152
 ; CHECK-NEXT: .llong  4616189618054758400
 
+; CHECK:      .globl  d_0
+; CHECK-NEXT: .align 3
+; CHECK-NEXT: d_0:
+; CHECK-NEXT: .llong 0
+
+; CHECK:      .globl  s_0
+; CHECK-NEXT: .align  1
+; CHECK-NEXT: s_0:
+; CHECK-NEXT: .short 0
+
+; CHECK:      .globl f_0
+; CHECK-NEXT: .align 2
+; CHECK-NEXT: f_0:
+; CHECK-NEXT: .long 0
+
 ; CHECK:      .comm   a,4,2
 ; CHECK-NEXT: .comm   b,8,3
 ; CHECK-NEXT: .comm   c,2,1
 
 ; OBJ:      File: {{.*}}aix-xcoff-data.ll.tmp.o
 ; OBJ-NEXT: Format: aixcoff-rs6000
 ; OBJ-NEXT: Arch: powerpc
 ; OBJ-NEXT: AddressSize: 32bit

 ; OBJ-NEXT:     Type: STYP_TEXT (0x20)
 ; OBJ-NEXT:   }
 
 ; OBJ:        Section {
 ; OBJ-NEXT:     Index: 2
 ; OBJ-NEXT:     Name: .data
 ; OBJ-NEXT:     PhysicalAddress: 0x0
 ; OBJ-NEXT:     VirtualAddress: 0x0
-; OBJ-NEXT:     Size: 0x50
+; OBJ-NEXT:     Size: 0x60
 ; OBJ-NEXT:     RawDataOffset: 0x8C
 ; OBJ-NEXT:     RelocationPointer: 0x0
 ; OBJ-NEXT:     LineNumberPointer: 0x0
 ; OBJ-NEXT:     NumberOfRelocations: 0
 ; OBJ-NEXT:     NumberOfLineNumbers: 0
 ; OBJ-NEXT:     Type: STYP_DATA (0x40)
 ; OBJ-NEXT:   }
 
 ; OBJ:        Section {
 ; OBJ-NEXT:     Index: 3
 ; OBJ-NEXT:     Name: .bss
-; OBJ-NEXT:     PhysicalAddress: 0x50
-; OBJ-NEXT:     VirtualAddress: 0x50
+; OBJ-NEXT:     PhysicalAddress: 0x60
+; OBJ-NEXT:     VirtualAddress: 0x60
 ; OBJ-NEXT:     Size: 0x14
 ; OBJ-NEXT:     RawDataOffset: 0x0
 ; OBJ-NEXT:     RelocationPointer: 0x0
 ; OBJ-NEXT:     LineNumberPointer: 0x0
 ; OBJ-NEXT:     NumberOfRelocations: 0
 ; OBJ-NEXT:     NumberOfLineNumbers: 0
 ; OBJ-NEXT:     Type: STYP_BSS (0x80)
 ; OBJ-NEXT:   }

 ; OBJ-NEXT:     Name: .data
 ; OBJ-NEXT:     Value (RelocatableAddress): 0x0
 ; OBJ-NEXT:     Section: .data
 ; OBJ-NEXT:     Type: 0x0
 ; OBJ-NEXT:     StorageClass: C_HIDEXT (0x6B)
 ; OBJ-NEXT:     NumberOfAuxEntries: 1
 ; OBJ-NEXT:     CSECT Auxiliary Entry {
 ; OBJ-NEXT:       Index: [[#INDX+3]]
-; OBJ-NEXT:       SectionLen: 80
+; OBJ-NEXT:       SectionLen: 96
 ; OBJ-NEXT:       ParameterHashIndex: 0x0
 ; OBJ-NEXT:       TypeChkSectNum: 0x0
 ; OBJ-NEXT:       SymbolAlignmentLog2: 5
 ; OBJ-NEXT:       SymbolType: XTY_SD (0x1)
 ; OBJ-NEXT:       StorageMappingClass: XMC_RW (0x5)
 ; OBJ-NEXT:       StabInfoIndex: 0x0
 ; OBJ-NEXT:       StabSectNum: 0x0
 ; OBJ-NEXT:     }

 ; OBJ-NEXT:       TypeChkSectNum: 0x0
 ; OBJ-NEXT:       SymbolAlignmentLog2: 0
 ; OBJ-NEXT:       SymbolType: XTY_LD (0x2)
 ; OBJ-NEXT:       StorageMappingClass: XMC_RW (0x5)
 ; OBJ-NEXT:       StabInfoIndex: 0x0
 ; OBJ-NEXT:       StabSectNum: 0x0
 ; OBJ-NEXT:     }
 ; OBJ-NEXT:   }
+
+; OBJ:        Symbol {
+; OBJ-NEXT:     Index: [[#INDX+20]]
+; OBJ-NEXT:     Name: d_0
+; OBJ-NEXT:     Value (RelocatableAddress): 0x50
+; OBJ-NEXT:     Section: .data
+; OBJ-NEXT:     Type: 0x0
+; OBJ-NEXT:     StorageClass: C_EXT (0x2)
+; OBJ-NEXT:     NumberOfAuxEntries: 1
+; OBJ-NEXT:     CSECT Auxiliary Entry {
+; OBJ-NEXT:       Index: [[#INDX+21]]
+; OBJ-NEXT:       ContainingCsectSymbolIndex: [[#INDX+2]]
+; OBJ-NEXT:       ParameterHashIndex: 0x0
+; OBJ-NEXT:       TypeChkSectNum: 0x0
+; OBJ-NEXT:       SymbolAlignmentLog2: 0
+; OBJ-NEXT:       SymbolType: XTY_LD (0x2)
+; OBJ-NEXT:       StorageMappingClass: XMC_RW (0x5)
+; OBJ-NEXT:       StabInfoIndex: 0x0
+; OBJ-NEXT:       StabSectNum: 0x0
+; OBJ-NEXT:     }
+; OBJ-NEXT:   }
+
+; OBJ:        Symbol {
+; OBJ-NEXT:     Index: [[#INDX+22]]
+; OBJ-NEXT:     Name: s_0
+; OBJ-NEXT:     Value (RelocatableAddress): 0x58
+; OBJ-NEXT:     Section: .data
+; OBJ-NEXT:     Type: 0x0
+; OBJ-NEXT:     StorageClass: C_EXT (0x2)
+; OBJ-NEXT:     NumberOfAuxEntries: 1
+; OBJ-NEXT:     CSECT Auxiliary Entry {
+; OBJ-NEXT:       Index: [[#INDX+23]]
+; OBJ-NEXT:       ContainingCsectSymbolIndex: [[#INDX+2]]
+; OBJ-NEXT:       ParameterHashIndex: 0x0
+; OBJ-NEXT:       TypeChkSectNum: 0x0
+; OBJ-NEXT:       SymbolAlignmentLog2: 0
+; OBJ-NEXT:       SymbolType: XTY_LD (0x2)
+; OBJ-NEXT:       StorageMappingClass: XMC_RW (0x5)
+; OBJ-NEXT:       StabInfoIndex: 0x0
+; OBJ-NEXT:       StabSectNum: 0x0
+; OBJ-NEXT:     }
+; OBJ-NEXT:   }
+
+; OBJ:        Symbol {
+; OBJ-NEXT:     Index: [[#INDX+24]]
+; OBJ-NEXT:     Name: f_0
+; OBJ-NEXT:     Value (RelocatableAddress): 0x5C
+; OBJ-NEXT:     Section: .data
+; OBJ-NEXT:     Type: 0x0
+; OBJ-NEXT:     StorageClass: C_EXT (0x2)
+; OBJ-NEXT:     NumberOfAuxEntries: 1
+; OBJ-NEXT:     CSECT Auxiliary Entry {
+; OBJ-NEXT:       Index: [[#INDX+25]]
+; OBJ-NEXT:       ContainingCsectSymbolIndex: [[#INDX+2]]
+; OBJ-NEXT:       ParameterHashIndex: 0x0
+; OBJ-NEXT:       TypeChkSectNum: 0x0
+; OBJ-NEXT:       SymbolAlignmentLog2: 0
+; OBJ-NEXT:       SymbolType: XTY_LD (0x2)
+; OBJ-NEXT:       StorageMappingClass: XMC_RW (0x5)
+; OBJ-NEXT:       StabInfoIndex: 0x0
+; OBJ-NEXT:       StabSectNum: 0x0
+; OBJ-NEXT:     }
+; OBJ-NEXT:   }
+
 ; OBJ:      ]