Add read-only data assembly writing

[DiggerLin]

Summary

the patch is based on Jason Liu's implement of Adding read-only data assembly writing.

[Xiangling_L]

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

51 ↗

(On Diff #229095)

Please remove this extra blank line.

[daltenty]

llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp

1752

The extra parenthesis around this expression are unnecessary

[DiggerLin]

llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp

1752

deleted the parenthesis of (GVKind.isMergeableCString() || GVKind.isMergeableConst()) , I prefer to keep the parenthesis of (!GVKind.isCommon() && !GVKind.isBSS() && !GVKind.isData() &&

!GVKind.isReadOnly())  for readable reason.

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

51 ↗

(On Diff #229095)

deleted ,thanks

[DiggerLin]

address comment

[daltenty]

LGTM

[jasonliu]

Test case is missing when the change is landed. Please add it back.

llvm/lib/BinaryFormat/XCOFF.cpp

StringRef XCOFF::getMappingClassString(XCOFF::StorageMappingClass SMC) {
   case XCOFF::XMC_RW:
     return "RW";
   case XCOFF::XMC_PR:
     return "PR";
   case XCOFF::XMC_TC0:
     return "TC0";
   case XCOFF::XMC_BS:
     return "BS";
+  case XCOFF::XMC_RO:
+    return "RO";
   default:
     report_fatal_error("Unhandled storage-mapping class.");
   }
 }

llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp

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;
 
+  if (Kind.isReadOnly() && !Kind.isMergeableConst() &&
+      !Kind.isMergeableCString())
+    return ReadOnlySection;
+
   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/MC/MCObjectFileInfo.cpp

void MCObjectFileInfo::initXCOFFMCObjectFileInfo(const Triple &T) {
   // csect for program code.
   TextSection = Ctx->getXCOFFSection(
       ".text", XCOFF::StorageMappingClass::XMC_PR, XCOFF::XTY_SD,
       XCOFF::C_HIDEXT, SectionKind::getText());
 
   DataSection = Ctx->getXCOFFSection(
       ".data", XCOFF::StorageMappingClass::XMC_RW, XCOFF::XTY_SD,
       XCOFF::C_HIDEXT, SectionKind::getData());
+
+  ReadOnlySection = Ctx->getXCOFFSection(
+      ".rodata", XCOFF::StorageMappingClass::XMC_RO, XCOFF::XTY_SD,
+      XCOFF::C_HIDEXT, SectionKind::getReadOnly());
 }
 
 void MCObjectFileInfo::InitMCObjectFileInfo(const Triple &TheTriple, bool PIC,
                                             MCContext &ctx,
                                             bool LargeCodeModel) {
   PositionIndependent = PIC;
   Ctx = &ctx;
 

llvm/lib/MC/MCSectionXCOFF.cpp

void MCSectionXCOFF::PrintSwitchToSection(const MCAsmInfo &MAI, const Triple &T,
   if (getKind().isText()) {
     if (getMappingClass() != XCOFF::XMC_PR)
       report_fatal_error("Unhandled storage-mapping class for .text csect");
 
     OS << "\t.csect " << QualName->getName() << '\n';
     return;
   }
 
+  if (getKind().isReadOnly()) {
+    if (getMappingClass() != XCOFF::XMC_RO)
+      report_fatal_error("Unhandled storage-mapping class for .rodata csect.");
+    OS << "\t.csect " << QualName->getName() << '\n';
+    return;
+  }
+
   if (getKind().isData()) {
     switch (getMappingClass()) {
     case XCOFF::XMC_RW:
     case XCOFF::XMC_DS:
       OS << "\t.csect " << QualName->getName() << '\n';
       break;
     case XCOFF::XMC_TC0:
       OS << "\t.toc\n";

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.isBSS() && !GVKind.isData())
+  if ((!GVKind.isCommon() && !GVKind.isBSS() && !GVKind.isData() &&
+       !GVKind.isReadOnly()) ||
+      GVKind.isMergeableCString() || GVKind.isMergeableConst())
     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);