Stubs out TLOF for AIX and add support for common vars in assembly output.

Stubs out a TargetLoweringObjectFileXCOFF class, implementing only
SelectSectionForGlobal for common symbols. Also adds an override of
EmitGlobalVariable in PPCAIXAsmPrinter which adds a number of defensive errors
and adds support for emitting common globals.

llvm-svn: 366727

4 files changed, 21 insertions, 4 deletions

diff --git a/llvm/lib/MC/MCAsmInfoXCOFF.cpp b/llvm/lib/MC/MCAsmInfoXCOFF.cpp
index 74c21f0c9e6..6a9bef6adff 100644
--- a/llvm/lib/MC/MCAsmInfoXCOFF.cpp
+++ b/llvm/lib/MC/MCAsmInfoXCOFF.cpp
@@ -15,4 +15,5 @@ void MCAsmInfoXCOFF::anchor() {}
 MCAsmInfoXCOFF::MCAsmInfoXCOFF() {
   IsLittleEndian = false;
   HasDotTypeDotSizeDirective = false;
+  COMMDirectiveAlignmentIsInBytes = false;
 }
diff --git a/llvm/lib/MC/MCContext.cpp b/llvm/lib/MC/MCContext.cpp
index 0dc2e2d37ca..ecd12fdc689 100644
--- a/llvm/lib/MC/MCContext.cpp
+++ b/llvm/lib/MC/MCContext.cpp
@@ -531,6 +531,7 @@ MCSectionWasm *MCContext::getWasmSection(const Twine &Section, SectionKind Kind,
 
 MCSectionXCOFF *MCContext::getXCOFFSection(StringRef Section,
                                            XCOFF::StorageMappingClass SMC,
+                                           XCOFF::SymbolType Type,
                                            SectionKind Kind,
                                            const char *BeginSymName) {
   // Do the lookup. If we have a hit, return it.
@@ -548,7 +549,7 @@ MCSectionXCOFF *MCContext::getXCOFFSection(StringRef Section,
     Begin = createTempSymbol(BeginSymName, false);
 
   MCSectionXCOFF *Result = new (XCOFFAllocator.Allocate())
-      MCSectionXCOFF(CachedName, SMC, Kind, Begin);
+      MCSectionXCOFF(CachedName, SMC, Type, Kind, Begin);
   Entry.second = Result;
 
   auto *F = new MCDataFragment();
diff --git a/llvm/lib/MC/MCObjectFileInfo.cpp b/llvm/lib/MC/MCObjectFileInfo.cpp
index 9f555abe140..6dc0e38e8e8 100644
--- a/llvm/lib/MC/MCObjectFileInfo.cpp
+++ b/llvm/lib/MC/MCObjectFileInfo.cpp
@@ -767,8 +767,9 @@ void MCObjectFileInfo::initXCOFFMCObjectFileInfo(const Triple &T) {
   // get placed into this csect. The choice of csect name is not a property of
   // the ABI or object file format. For example, the XL compiler uses an unnamed
   // csect for program code.
-  TextSection = Ctx->getXCOFFSection(
-      ".text", XCOFF::StorageMappingClass::XMC_PR, SectionKind::getText());
+  TextSection =
+      Ctx->getXCOFFSection(".text", XCOFF::StorageMappingClass::XMC_PR,
+                           XCOFF::XTY_SD, SectionKind::getText());
 }
 
 void MCObjectFileInfo::InitMCObjectFileInfo(const Triple &TheTriple, bool PIC,
diff --git a/llvm/lib/MC/MCSectionXCOFF.cpp b/llvm/lib/MC/MCSectionXCOFF.cpp
index d1a63734502..740365f0476 100644
--- a/llvm/lib/MC/MCSectionXCOFF.cpp
+++ b/llvm/lib/MC/MCSectionXCOFF.cpp
@@ -19,15 +19,29 @@ void MCSectionXCOFF::PrintSwitchToSection(const MCAsmInfo &MAI, const Triple &T,
                                           raw_ostream &OS,
                                           const MCExpr *Subsection) const {
   if (getKind().isText()) {
+    if (getMappingClass() != XCOFF::XMC_PR)
+      llvm_unreachable("Unsupported storage-mapping class for .text csect");
+
     OS << "\t.csect " << getSectionName() << "["
        << "PR"
        << "]" << '\n';
     return;
   }
 
+  if (getKind().isCommon()) {
+    if (getMappingClass() != XCOFF::XMC_RW)
+      llvm_unreachable("Unsupported storage-mapping class for common csect");
+    if (getCSectType() != XCOFF::XTY_CM)
+      llvm_unreachable("wrong csect type for common csect");
+    // Don't have to print a directive for switching to section for commons.
+    // '.comm' and '.lcomm' directives for the variable will create the needed
+    // csect.
+    return;
+  }
+
   report_fatal_error("Printing for this SectionKind is unimplemented.");
 }
 
 bool MCSectionXCOFF::UseCodeAlign() const { return getKind().isText(); }
 
-bool MCSectionXCOFF::isVirtualSection() const { return !getKind().isCommon(); }
+bool MCSectionXCOFF::isVirtualSection() const { return XCOFF::XTY_CM == Type; }