[PowerPC][AIX] Adds support for writing the .data section in assembly files

Summary:
Adds support for generating the .data section in assembly files for global variables with a non-zero initialization. The support for writing the .data section in XCOFF object files will be added in a follow-on patch. Any relocations are not included in this patch.

Reviewers: hubert.reinterpretcast, sfertile, jasonliu, daltenty, Xiangling_L

Reviewed by: hubert.reinterpretcast

Subscribers: nemanjai, hiraditya, kbarton, MaskRay, jsji, wuzish, shchenz, DiggerLin, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66154

llvm-svn: 369869

7 files changed, 60 insertions, 13 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 8530174bb6c..220c4758956 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -162,8 +162,9 @@ static gcp_map_type &getGCMap(void *&P) {
 /// getGVAlignmentLog2 - Return the alignment to use for the specified global
 /// value in log2 form.  This rounds up to the preferred alignment if possible
 /// and legal.
-static unsigned getGVAlignmentLog2(const GlobalValue *GV, const DataLayout &DL,
-                                   unsigned InBits = 0) {
+unsigned AsmPrinter::getGVAlignmentLog2(const GlobalValue *GV,
+                                        const DataLayout &DL,
+                                        unsigned InBits) {
   unsigned NumBits = 0;
   if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV))
     NumBits = DL.getPreferredAlignmentLog(GVar);
diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index 1505c9d5e15..653f30a12a2 100644
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -1849,6 +1849,9 @@ MCSection *TargetLoweringObjectFileXCOFF::SelectSectionForGlobal(
   if (Kind.isText())
     return TextSection;
 
+  if (Kind.isData())
+    return DataSection;
+
   report_fatal_error("XCOFF other section types not yet implemented.");
 }
 
diff --git a/llvm/lib/MC/MCAsmInfoXCOFF.cpp b/llvm/lib/MC/MCAsmInfoXCOFF.cpp
index 92dc505c0a1..13939f6a65f 100644
--- a/llvm/lib/MC/MCAsmInfoXCOFF.cpp
+++ b/llvm/lib/MC/MCAsmInfoXCOFF.cpp
@@ -17,4 +17,8 @@ MCAsmInfoXCOFF::MCAsmInfoXCOFF() {
   HasDotTypeDotSizeDirective = false;
   COMMDirectiveAlignmentIsInBytes = false;
   LCOMMDirectiveAlignmentType = LCOMM::Log2Alignment;
+  UseDotAlignForAlignment = true;
+  AsciiDirective = nullptr; // not supported
+  AscizDirective = nullptr; // not supported
+  Data64bitsDirective = "\t.llong\t";
 }
diff --git a/llvm/lib/MC/MCAsmStreamer.cpp b/llvm/lib/MC/MCAsmStreamer.cpp
index e20ba2f96e3..e37bc4a4d70 100644
--- a/llvm/lib/MC/MCAsmStreamer.cpp
+++ b/llvm/lib/MC/MCAsmStreamer.cpp
@@ -1119,6 +1119,16 @@ void MCAsmStreamer::emitFill(const MCExpr &NumValues, int64_t Size,
 void MCAsmStreamer::EmitValueToAlignment(unsigned ByteAlignment, int64_t Value,
                                          unsigned ValueSize,
                                          unsigned MaxBytesToEmit) {
+  if (MAI->useDotAlignForAlignment()) {
+    if (!isPowerOf2_32(ByteAlignment))
+      report_fatal_error("Only power-of-two alignments are supported "
+                         "with .align.");
+    OS << "\t.align\t";
+    OS << Log2_32(ByteAlignment);
+    EmitEOL();
+    return;
+  }
+
   // Some assemblers don't support non-power of two alignments, so we always
   // emit alignments as a power of two if possible.
   if (isPowerOf2_32(ByteAlignment)) {
diff --git a/llvm/lib/MC/MCObjectFileInfo.cpp b/llvm/lib/MC/MCObjectFileInfo.cpp
index d59453aa1ca..861e5013b6b 100644
--- a/llvm/lib/MC/MCObjectFileInfo.cpp
+++ b/llvm/lib/MC/MCObjectFileInfo.cpp
@@ -770,6 +770,10 @@ void MCObjectFileInfo::initXCOFFMCObjectFileInfo(const Triple &T) {
   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());
 }
 
 void MCObjectFileInfo::InitMCObjectFileInfo(const Triple &TheTriple, bool PIC,
diff --git a/llvm/lib/MC/MCSectionXCOFF.cpp b/llvm/lib/MC/MCSectionXCOFF.cpp
index d00a435b625..db277521db2 100644
--- a/llvm/lib/MC/MCSectionXCOFF.cpp
+++ b/llvm/lib/MC/MCSectionXCOFF.cpp
@@ -28,6 +28,16 @@ void MCSectionXCOFF::PrintSwitchToSection(const MCAsmInfo &MAI, const Triple &T,
     return;
   }
 
+  if (getKind().isData()) {
+    assert(getMappingClass() == XCOFF::XMC_RW &&
+           "Unhandled storage-mapping class for data section.");
+
+    OS << "\t.csect " << getSectionName() << "["
+       << "RW"
+       << "]" << '\n';
+    return;
+  }
+
   if (getKind().isBSSLocal() || getKind().isCommon()) {
     assert((getMappingClass() == XCOFF::XMC_RW ||
             getMappingClass() == XCOFF::XMC_BS) &&
diff --git a/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp b/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
index 8d23238e615..b1d988db839 100644
--- a/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
+++ b/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
@@ -1659,8 +1659,9 @@ void PPCAIXAsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
     report_fatal_error("COMDAT not yet supported by AIX.");
 
   SectionKind GVKind = getObjFileLowering().getKindForGlobal(GV, TM);
-  if (!GVKind.isCommon() && !GVKind.isBSSLocal())
-    report_fatal_error("Only common variables are supported on AIX for now.");
+  if (!GVKind.isCommon() && !GVKind.isBSSLocal() && !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>(
@@ -1668,20 +1669,34 @@ void PPCAIXAsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
   OutStreamer->SwitchSection(CSect);
 
   // Create the symbol, set its storage class, and emit it.
-  MCSymbolXCOFF *XSym = cast<MCSymbolXCOFF>(getSymbol(GV));
-  XSym->setStorageClass(
+  MCSymbolXCOFF *GVSym = cast<MCSymbolXCOFF>(getSymbol(GV));
+  GVSym->setStorageClass(
       TargetLoweringObjectFileXCOFF::getStorageClassForGlobal(GV));
-  XSym->setContainingCsect(CSect);
+  GVSym->setContainingCsect(CSect);
 
   const DataLayout &DL = GV->getParent()->getDataLayout();
-  unsigned Align =
+
+  // Handle common symbols.
+  if (GVKind.isCommon() || GVKind.isBSSLocal()) {
+    unsigned Align =
       GV->getAlignment() ? GV->getAlignment() : DL.getPreferredAlignment(GV);
-  uint64_t Size = DL.getTypeAllocSize(GV->getType()->getElementType());
+    uint64_t Size = DL.getTypeAllocSize(GV->getType()->getElementType());
+
+    if (GVKind.isBSSLocal())
+      OutStreamer->EmitXCOFFLocalCommonSymbol(GVSym, Size, Align);
+    else
+      OutStreamer->EmitCommonSymbol(GVSym, Size, Align);
+    return;
+  }
+
+  // Get the alignment in the log2 form.
+  const unsigned AlignLog = getGVAlignmentLog2(GV, DL);
 
-  if (GVKind.isBSSLocal())
-    OutStreamer->EmitXCOFFLocalCommonSymbol(XSym, Size, Align);
-  else
-    OutStreamer->EmitCommonSymbol(XSym, Size, Align);
+  MCSymbol *EmittedInitSym = GVSym;
+  EmitLinkage(GV, EmittedInitSym);
+  EmitAlignment(AlignLog, GV);
+  OutStreamer->EmitLabel(EmittedInitSym);
+  EmitGlobalConstant(GV->getParent()->getDataLayout(), GV->getInitializer());
 }
 
 /// createPPCAsmPrinterPass - Returns a pass that prints the PPC assembly code