[AIX][TLS] Add ASM portion changes to support TLSGD relocations to XCOFF objects

- Add new variantKinds for the symbol's variable offset and region handle
- Print the proper relocation specifier @gd in the asm streamer when emitting
  the TC Entry for the variable offset for the symbol
- Fix the switch section failure between the TC Entry of variable offset and
  region handle
- Put .__tls_get_addr symbol in the ProgramCodeSects with XTY_ER property

Reviewed by: sfertile

Differential Revision: https://reviews.llvm.org/D100956

Author: VictorHuangIBM

llvm/include/llvm/MC/MCExpr.h

@@ -296,6 +296,8 @@ class MCSymbolRefExpr : public MCExpr {
     VK_PPC_GOT_TLSGD_HI,    // symbol@got@tlsgd@h
     VK_PPC_GOT_TLSGD_HA,    // symbol@got@tlsgd@ha
     VK_PPC_TLSGD,           // symbol@tlsgd
+    VK_PPC_AIX_TLSGD,       // symbol@gd
+    VK_PPC_AIX_TLSGDM,      // symbol@m
     VK_PPC_GOT_TLSLD,       // symbol@got@tlsld
     VK_PPC_GOT_TLSLD_LO,    // symbol@got@tlsld@l
     VK_PPC_GOT_TLSLD_HI,    // symbol@got@tlsld@h

llvm/lib/MC/MCExpr.cpp

@@ -322,6 +322,10 @@ StringRef MCSymbolRefExpr::getVariantKindName(VariantKind Kind) {
   case VK_PPC_GOT_TLSGD_HI: return "got@tlsgd@h";
   case VK_PPC_GOT_TLSGD_HA: return "got@tlsgd@ha";
   case VK_PPC_TLSGD: return "tlsgd";
+  case VK_PPC_AIX_TLSGD:
+    return "gd";
+  case VK_PPC_AIX_TLSGDM:
+    return "m";
   case VK_PPC_GOT_TLSLD: return "got@tlsld";
   case VK_PPC_GOT_TLSLD_LO: return "got@tlsld@l";
   case VK_PPC_GOT_TLSLD_HI: return "got@tlsld@h";

llvm/lib/Target/PowerPC/MCTargetDesc/PPCMCTargetDesc.cpp

@@ -145,11 +145,14 @@ class PPCTargetAsmStreamer : public PPCTargetStreamer {
       MCSymbolXCOFF *TCSym =
           cast<MCSectionXCOFF>(Streamer.getCurrentSectionOnly())
               ->getQualNameSymbol();
-      // If the variant kind is TLSGD the entry represents the region handle for
-      // the symbol, we prefix the name with a dot and we add the @m
-      // relocation specifier.
-      if (Kind == MCSymbolRefExpr::VariantKind::VK_PPC_TLSGD)
-        OS << "\t.tc ." << TCSym->getName() << "," << XSym->getName() << "@m\n";
+      // If the variant kind is VK_PPC_AIX_TLSGDM the entry represents the
+      // region handle for the symbol, we add the relocation specifier @m.
+      // If the variant kind is VK_PPC_AIX_TLSGD the entry represents the
+      // variable offset for the symbol, we add the relocation specifier @gd.
+      if (Kind == MCSymbolRefExpr::VariantKind::VK_PPC_AIX_TLSGD ||
+          Kind == MCSymbolRefExpr::VariantKind::VK_PPC_AIX_TLSGDM)
+        OS << "\t.tc " << TCSym->getName() << "," << XSym->getName() << "@"
+           << MCSymbolRefExpr::getVariantKindName(Kind) << '\n';
       else
         OS << "\t.tc " << TCSym->getName() << "," << XSym->getName() << '\n';
 

llvm/lib/Target/PowerPC/PPC.h

@@ -116,7 +116,8 @@ FunctionPass *createPPCCTRLoops();
     MO_PCREL_OPT_FLAG = 16,
 
     /// MO_TLSGD_FLAG - If this bit is set the symbol reference is relative to
-    /// TLS General Dynamic model.
+    /// TLS General Dynamic model for Linux and the variable offset of TLS
+    /// General Dynamic model for AIX.
     MO_TLSGD_FLAG = 32,
 
     /// MO_TPREL_FLAG - If this bit is set the symbol reference is relative to
@@ -127,6 +128,10 @@ FunctionPass *createPPCCTRLoops();
     /// TLS Local Dynamic model.
     MO_TLSLD_FLAG = 128,
 
+    /// MO_TLSGDM_FLAG - If this bit is set the symbol reference is relative
+    /// to the region handle of TLS General Dynamic model for AIX.
+    MO_TLSGDM_FLAG = 256,
+
     /// MO_GOT_TLSGD_PCREL_FLAG - A combintaion of flags, if these bits are set
     /// they should produce the relocation @got@tlsgd@pcrel.
     /// Fix up is VK_PPC_GOT_TLSGD_PCREL

llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp

@@ -522,12 +522,20 @@ void PPCAsmPrinter::LowerPATCHPOINT(StackMaps &SM, const MachineInstr &MI) {
     EmitToStreamer(*OutStreamer, MCInstBuilder(PPC::NOP));
 }
 
+/// This helper function creates the TlsGetAddr MCSymbol for AIX. We will
+/// create the csect and use the qual-name symbol instead of creating just the
+/// external symbol.
+static MCSymbol *createMCSymbolForTlsGetAddr(MCContext &Ctx) {
+  return Ctx
+      .getXCOFFSection(".__tls_get_addr", SectionKind::getText(),
+                       XCOFF::CsectProperties(XCOFF::XMC_PR, XCOFF::XTY_ER))
+      ->getQualNameSymbol();
+}
+
 /// EmitTlsCall -- Given a GETtls[ld]ADDR[32] instruction, print a
 /// call to __tls_get_addr to the current output stream.
 void PPCAsmPrinter::EmitTlsCall(const MachineInstr *MI,
                                 MCSymbolRefExpr::VariantKind VK) {
-  StringRef Name = Subtarget->isAIXABI() ? ".__tls_get_addr" : "__tls_get_addr";
-  MCSymbol *TlsGetAddr = OutContext.getOrCreateSymbol(Name);
   MCSymbolRefExpr::VariantKind Kind = MCSymbolRefExpr::VK_None;
   unsigned Opcode = PPC::BL8_NOP_TLS;
 
@@ -558,13 +566,15 @@ void PPCAsmPrinter::EmitTlsCall(const MachineInstr *MI,
     assert(MI->getOperand(2).isReg() &&
            MI->getOperand(2).getReg() == VarOffsetReg &&
            "GETtls[ld]ADDR[32] must read GPR4");
-    MCSymbol *TlsGetAddrA = OutContext.getOrCreateSymbol(Name);
+    MCSymbol *TlsGetAddr = createMCSymbolForTlsGetAddr(OutContext);
     const MCExpr *TlsRef = MCSymbolRefExpr::create(
-        TlsGetAddrA, MCSymbolRefExpr::VK_None, OutContext);
+        TlsGetAddr, MCSymbolRefExpr::VK_None, OutContext);
     EmitToStreamer(*OutStreamer, MCInstBuilder(PPC::BLA).addExpr(TlsRef));
     return;
   }
 
+  MCSymbol *TlsGetAddr = OutContext.getOrCreateSymbol("__tls_get_addr");
+
   if (Subtarget->is32BitELFABI() && isPositionIndependent())
     Kind = MCSymbolRefExpr::VK_PLT;
 
@@ -673,10 +683,12 @@ void PPCAsmPrinter::emitInstruction(const MachineInstr *MI) {
   };
   auto GetVKForMO = [&](const MachineOperand &MO) {
     // For GD TLS access on AIX, we have two TOC entries for the symbol (one for
-    // the offset and the other for the region handle). They are differentiated
-    // by the presence of the PPCII::MO_TLSGD_FLAG.
-    if (IsAIX && (MO.getTargetFlags() & PPCII::MO_TLSGD_FLAG))
-      return MCSymbolRefExpr::VariantKind::VK_PPC_TLSGD;
+    // the variable offset and the other for the region handle). They are
+    // differentiated by MO_TLSGD_FLAG and MO_TLSGDM_FLAG.
+    if (MO.getTargetFlags() & PPCII::MO_TLSGDM_FLAG)
+      return MCSymbolRefExpr::VariantKind::VK_PPC_AIX_TLSGDM;
+    if (MO.getTargetFlags() & PPCII::MO_TLSGD_FLAG)
+      return MCSymbolRefExpr::VariantKind::VK_PPC_AIX_TLSGD;
     return MCSymbolRefExpr::VariantKind::VK_None;
   };
 
@@ -2232,9 +2244,22 @@ void PPCAIXAsmPrinter::emitEndOfAsmFile(Module &M) {
       static_cast<PPCTargetStreamer *>(OutStreamer->getTargetStreamer());
 
   for (auto &I : TOC) {
-    // Setup the csect for the current TC entry.
-    MCSectionXCOFF *TCEntry = cast<MCSectionXCOFF>(
-        getObjFileLowering().getSectionForTOCEntry(I.first.first, TM));
+    MCSectionXCOFF *TCEntry;
+    // Setup the csect for the current TC entry. If the variant kind is
+    // VK_PPC_AIX_TLSGDM the entry represents the region handle, we create a
+    // new symbol to prefix the name with a dot.
+    if (I.first.second == MCSymbolRefExpr::VariantKind::VK_PPC_AIX_TLSGDM) {
+      SmallString<128> Name;
+      StringRef Prefix = ".";
+      Name += Prefix;
+      Name += I.first.first->getName();
+      MCSymbol *S = OutContext.getOrCreateSymbol(Name);
+      TCEntry = cast<MCSectionXCOFF>(
+          getObjFileLowering().getSectionForTOCEntry(S, TM));
+    } else {
+      TCEntry = cast<MCSectionXCOFF>(
+          getObjFileLowering().getSectionForTOCEntry(I.first.first, TM));
+    }
     OutStreamer->SwitchSection(TCEntry);
 
     OutStreamer->emitLabel(I.second);
@@ -2317,7 +2342,7 @@ void PPCAIXAsmPrinter::emitInstruction(const MachineInstr *MI) {
   case PPC::GETtlsADDR32AIX: {
     // The reference to .__tls_get_addr is unknown to the assembler
     // so we need to emit an external symbol reference.
-    MCSymbol *TlsGetAddr = OutContext.getOrCreateSymbol(".__tls_get_addr");
+    MCSymbol *TlsGetAddr = createMCSymbolForTlsGetAddr(OutContext);
     ExtSymSDNodeSymbols.insert(TlsGetAddr);
     break;
   }

llvm/lib/Target/PowerPC/PPCISelLowering.cpp

@@ -3146,11 +3146,12 @@ SDValue PPCTargetLowering::LowerGlobalTLSAddressAIX(SDValue Op,
   // all the GlobalTLSAddress nodes are lowered with this model.
   // We need to generate two TOC entries, one for the variable offset, one for
   // the region handle. The global address for the TOC entry of the region
-  // handle is created with the MO_TLSGD_FLAG flag so we can easily identify
-  // this entry and add the right relocation.
-  SDValue VariableOffsetTGA = DAG.getTargetGlobalAddress(GV, dl, PtrVT, 0, 0);
-  SDValue RegionHandleTGA =
+  // handle is created with the MO_TLSGDM_FLAG flag and the global address
+  // for the TOC entry of the variable offset is created with MO_TLSGD_FLAG.
+  SDValue VariableOffsetTGA =
       DAG.getTargetGlobalAddress(GV, dl, PtrVT, 0, PPCII::MO_TLSGD_FLAG);
+  SDValue RegionHandleTGA =
+      DAG.getTargetGlobalAddress(GV, dl, PtrVT, 0, PPCII::MO_TLSGDM_FLAG);
   SDValue VariableOffset = getTOCEntry(DAG, dl, VariableOffsetTGA);
   SDValue RegionHandle = getTOCEntry(DAG, dl, RegionHandleTGA);
   return DAG.getNode(PPCISD::TLSGD_AIX, dl, PtrVT, VariableOffset,

llvm/lib/Target/PowerPC/PPCInstrInfo.cpp

@@ -2893,6 +2893,7 @@ PPCInstrInfo::getSerializableBitmaskMachineOperandTargetFlags() const {
       {MO_TLSGD_FLAG, "ppc-tlsgd"},
       {MO_TLSLD_FLAG, "ppc-tlsld"},
       {MO_TPREL_FLAG, "ppc-tprel"},
+      {MO_TLSGDM_FLAG, "ppc-tlsgdm"},
       {MO_GOT_TLSGD_PCREL_FLAG, "ppc-got-tlsgd-pcrel"},
       {MO_GOT_TLSLD_PCREL_FLAG, "ppc-got-tlsld-pcrel"},
       {MO_GOT_TPREL_PCREL_FLAG, "ppc-got-tprel-pcrel"}};