[AIX][XCOFF] Support Mergeable2ByteCString and Mergeable4ByteCString

[daltenty]

llvm/test/CodeGen/PowerPC/aix-xcoff-mergeable-str.ll

70

nit: Should we really be matching the memonics column of the objdump output since it's not meaningful here? We really only care about the raw bytes.

[daltenty]

llvm/test/CodeGen/PowerPC/aix-xcoff-mergeable-str.ll

71

These {{.*}}, etc. are redundant. The check-next directives don't require you to consume the whole line of output. Same for all the lines bellow.

[daltenty]

LGTM with minor nit

llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp

if (Kind.isBSSLocal() || Kind.isCommon()) {
     XCOFF::StorageClass SC =
         TargetLoweringObjectFileXCOFF::getStorageClassForGlobal(GO);
     return getContext().getXCOFFSection(
         Name, Kind.isBSSLocal() ? XCOFF::XMC_BS : XCOFF::XMC_RW, XCOFF::XTY_CM,
         SC, Kind, /* BeginSymbolName */ nullptr);
   }
 
   if (Kind.isMergeableCString()) {
-    if (!Kind.isMergeable1ByteCString())
-      report_fatal_error("Unhandled multi-byte mergeable string kind.");
-
     unsigned Align = GO->getParent()->getDataLayout().getPreferredAlignment(
         cast<GlobalVariable>(GO));
 
     unsigned EntrySize = getEntrySizeForKind(Kind);
     std::string SizeSpec = ".rodata.str" + utostr(EntrySize) + ".";
     SmallString<128> Name;
     Name = SizeSpec + utostr(Align);
 

llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp

if (!GV->hasInitializer())
     return;
 
   // Create the symbol, set its storage class.
   MCSymbolXCOFF *GVSym = cast<MCSymbolXCOFF>(getSymbol(GV));
   GVSym->setStorageClass(
       TargetLoweringObjectFileXCOFF::getStorageClassForGlobal(GV));
 
   SectionKind GVKind = getObjFileLowering().getKindForGlobal(GV, TM);
-  if ((!GVKind.isGlobalWriteableData() && !GVKind.isReadOnly()) ||
-      GVKind.isMergeable2ByteCString() || GVKind.isMergeable4ByteCString())
+  if (!GVKind.isGlobalWriteableData() && !GVKind.isReadOnly()) {
     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);
   GVSym->setContainingCsect(Csect);
 
   const DataLayout &DL = GV->getParent()->getDataLayout();

llvm/test/CodeGen/PowerPC/aix-xcoff-mergeable-str.ll

 ; This file tests the codegen of mergeable strings in AIX assembly only.
 ; Once the codegen of mergeable strings for XCOFF object files is supported
 ; the test in this file should be merged into aix-xcoff-data.ll with additional
 ; tests for XCOFF object files.
 
-; RUN: llc -verify-machineinstrs -mcpu=pwr7 \
+; RUN: llc -verify-machineinstrs -mcpu=pwr4 \
 ; RUN:     -mtriple powerpc-ibm-aix-xcoff < %s | FileCheck %s
-; RUN: llc -verify-machineinstrs -mcpu=pwr7 \
+; RUN: llc -verify-machineinstrs -mcpu=pwr4 \
 ; RUN:     -mtriple powerpc64-ibm-aix-xcoff < %s | FileCheck %s
 
-; RUN: llc -verify-machineinstrs -mcpu=pwr7 -mtriple powerpc-ibm-aix-xcoff -filetype=obj -o %t.o < %s
+; RUN: llc -verify-machineinstrs -mcpu=pwr4 -mtriple powerpc-ibm-aix-xcoff -filetype=obj -o %t.o < %s
 ; RUN: llvm-objdump -D %t.o | FileCheck --check-prefix=CHECKOBJ %s
 
+@magic16 = private unnamed_addr constant [4 x i16] [i16 264, i16 272, i16 213, i16 0], align 2
+@magic32 =  private unnamed_addr constant [4 x i32] [i32 464, i32 472, i32 413, i32 0], align 4
 @strA = private unnamed_addr constant [14 x i8] c"hello world!\0A\00", align 1
 @.str = private unnamed_addr constant [9 x i8] c"abcdefgh\00", align 1
 @p = global i8* getelementptr inbounds ([9 x i8], [9 x i8]* @.str, i32 0, i32 0), align 4
 
 ; Function Attrs: noinline nounwind optnone
 define i8 @foo() #0 {
 entry:
   %0 = load i8*, i8** @p, align 4
   %1 = load i8, i8* %0, align 1
   ret i8 %1
 }
 
-; CHECK:      .csect .rodata.str1.1[RO]
+; CHECK:   .csect .rodata.str2.2[RO]
+; CHECK-NEXT:   .align  1
+; CHECK-NEXT: .Lmagic16:
+; CHECK-NEXT:   .short  264                     # 0x108
+; CHECK-NEXT:   .short  272                     # 0x110
+; CHECK-NEXT:   .short  213                     # 0xd5
+; CHECK-NEXT:   .short  0                       # 0x0
+; CHECK-NEXT:   .csect .rodata.str4.4[RO]
+; CHECK-NEXT:   .align  2
+; CHECK-NEXT: .Lmagic32:
+; CHECK-NEXT:   .long   464                     # 0x1d0
+; CHECK-NEXT:   .long   472                     # 0x1d8
+; CHECK-NEXT:   .long   413                     # 0x19d
+; CHECK-NEXT:   .long   0                       # 0x0
+; CHECK-NEXT:   .csect .rodata.str1.1[RO]
 ; CHECK-NEXT: .LstrA:
 ; CHECK-NEXT: .byte   104
 ; CHECK-NEXT: .byte   101
 ; CHECK-NEXT: .byte   108
 ; CHECK-NEXT: .byte   108
 ; CHECK-NEXT: .byte   111
 ; CHECK-NEXT: .byte   32
 ; CHECK-NEXT: .byte   119

 ; CHECK-NEXT: .byte   99
 ; CHECK-NEXT: .byte   100
 ; CHECK-NEXT: .byte   101
 ; CHECK-NEXT: .byte   102
 ; CHECK-NEXT: .byte   103
 ; CHECK-NEXT: .byte   104
 ; CHECK-NEXT: .byte   0
 
-; CHECKOBJ: 00000010 .rodata.str1.1:
-; CHECKOBJ-NEXT:       10: 68 65 6c 6c                   xori 5, 3, 27756
-; CHECKOBJ-NEXT:       14: 6f 20 77 6f                   xoris 0, 25, 30575
-; CHECKOBJ-NEXT:       18: 72 6c 64 21                   andi. 12, 19, 25633
-; CHECKOBJ-NEXT:       1c: 0a 00 61 62                   tdlti   0, 24930{{[[:space:]] *}}
-; CHECKOBJ-NEXT: 0000001e .L.str:
-; CHECKOBJ-NEXT:       1e: 61 62 63 64                   ori 2, 11, 25444
-; CHECKOBJ-NEXT:       22: 65 66 67 68                   oris 6, 11, 26472
-; CHECKOBJ-NEXT:       26: 00                            <unknown>
-; CHECKOBJ-NEXT:       27: 00                            <unknown>
+; CHECKOBJ:     00000010 .rodata.str2.2:
+; CHECKOBJ-NEXT:       10: 01 08 01 10                          <unknown>
+; CHECKOBJ-NEXT:       14: 00 d5 00 00                          <unknown>{{[[:space:]] *}}
+; CHECKOBJ-NEXT: 00000018 .rodata.str4.4:
+; CHECKOBJ-NEXT:       18: 00 00 01 d0                          <unknown>
+; CHECKOBJ-NEXT:       1c: 00 00 01 d8                          <unknown>
+; CHECKOBJ-NEXT:       20: 00 00 01 9d                          <unknown>
+; CHECKOBJ-NEXT:       24: 00 00 00 00                          <unknown>{{[[:space:]] *}}
+; CHECKOBJ-NEXT: 00000028 .rodata.str1.1:
+; CHECKOBJ-NEXT:       28: 68 65 6c 6c                          xori 5, 3, 27756
+; CHECKOBJ-NEXT:       2c: 6f 20 77 6f                          xoris 0, 25, 30575
+; CHECKOBJ-NEXT:       30: 72 6c 64 21                          andi. 12, 19, 25633
+; CHECKOBJ-NEXT:       34: 0a 00 61 62                          tdlti   0, 24930{{[[:space:]] *}}
+; CHECKOBJ-NEXT: 00000036 .L.str:
+; CHECKOBJ-NEXT:       36: 61 62 63 64                          ori 2, 11, 25444
+; CHECKOBJ-NEXT:       3a: 65 66 67 68                          oris 6, 11, 26472
+; CHECKOBJ-NEXT:       3e: 00                                   <unknown>
+; CHECKOBJ-NEXT:       3f: 00                                   <unknown>
+