[XCOFF][AIX] Use TE storage mapping class when large code model is enabled

[jasonliu]

Summary

Use TE SMC instead of TC SMC in large code model mode,
so that large code model TOC entries could get placed after all
the small code model TOC entries, which reduces the chance of TOC overflow.

[Xiangling_L]

so that code compiled with large code model TOC reference would not
take up spaces from the normal small code model TOC reference.

Probably we need to rephrase the description here.
As my understanding, TE SMC entry is possible to take spaces from the normal small code model TOC reference? But it would let TC SMC entry take up those space first and TE then follows.

llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp

2204

Slightly prefer inline IsLarge since it's used once and also not too long.

[jasonliu]

Address comment.

[Xiangling_L]

LGTM. thanks.

llvm/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h

MCSection *getSectionForConstant(const DataLayout &DL, SectionKind Kind,
                                    const Constant *C,
                                    Align &Alignment) const override;
 
   static XCOFF::StorageClass getStorageClassForGlobal(const GlobalValue *GV);
 
   MCSection *
   getSectionForFunctionDescriptor(const Function *F,
                                   const TargetMachine &TM) const override;
-  MCSection *getSectionForTOCEntry(const MCSymbol *Sym) const override;
+  MCSection *getSectionForTOCEntry(const MCSymbol *Sym,
+                                   const TargetMachine &TM) const override;
 
   /// For external functions, this will always return a function descriptor
   /// csect.
   MCSection *
   getSectionForExternalReference(const GlobalObject *GO,
                                  const TargetMachine &TM) const override;
 
   /// For functions, this will always return a function descriptor symbol.

llvm/include/llvm/Target/TargetLoweringObjectFile.h

public:
   getSectionForFunctionDescriptor(const Function *F,
                                   const TargetMachine &TM) const {
     return nullptr;
   }
 
   /// On targets that support TOC entries, return a section for the entry given
   /// the symbol it refers to.
   /// TODO: Implement this interface for existing ELF targets.
-  virtual MCSection *getSectionForTOCEntry(const MCSymbol *S) const {
+  virtual MCSection *getSectionForTOCEntry(const MCSymbol *S,
+                                           const TargetMachine &TM) const {
     return nullptr;
   }
 
   /// On targets that associate external references with a section, return such
   /// a section for the given external global.
   virtual MCSection *
   getSectionForExternalReference(const GlobalObject *GO,
                                  const TargetMachine &TM) const {

llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp

MCSection *TargetLoweringObjectFileXCOFF::getSectionForFunctionDescriptor(
   SmallString<128> NameStr;
   getNameWithPrefix(NameStr, F, TM);
   return getContext().getXCOFFSection(NameStr, XCOFF::XMC_DS, XCOFF::XTY_SD,
                                       getStorageClassForGlobal(F),
                                       SectionKind::getData());
 }
 
 MCSection *TargetLoweringObjectFileXCOFF::getSectionForTOCEntry(
-    const MCSymbol *Sym) const {
+    const MCSymbol *Sym, const TargetMachine &TM) const {
+  // Use TE storage-mapping class when large code model is enabled so that
+  // the chance of needing -bbigtoc is decreased.
+  const bool IsLarge = TM.getCodeModel() == CodeModel::Large;
   return getContext().getXCOFFSection(
-      cast<MCSymbolXCOFF>(Sym)->getSymbolTableName(), XCOFF::XMC_TC,
-      XCOFF::XTY_SD, XCOFF::C_HIDEXT, SectionKind::getData());
+      cast<MCSymbolXCOFF>(Sym)->getSymbolTableName(),
+      IsLarge ? XCOFF::XMC_TE : XCOFF::XMC_TC, XCOFF::XTY_SD, XCOFF::C_HIDEXT,
+      SectionKind::getData());
 }

llvm/lib/MC/MCSectionXCOFF.cpp

void MCSectionXCOFF::PrintSwitchToSection(const MCAsmInfo &MAI, const Triple &T,
 
   if (getKind().isData()) {
     switch (getMappingClass()) {
     case XCOFF::XMC_RW:
     case XCOFF::XMC_DS:
       printCsectDirective(OS);
       break;
     case XCOFF::XMC_TC:
+    case XCOFF::XMC_TE:
       break;
     case XCOFF::XMC_TC0:
       OS << "\t.toc\n";
       break;
     default:
       report_fatal_error(
           "Unhandled storage-mapping class for .data csect.");
     }

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

 #include "MCTargetDesc/PPCMCAsmInfo.h"
 #include "PPCELFStreamer.h"
 #include "PPCTargetStreamer.h"
 #include "TargetInfo/PowerPCTargetInfo.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/BinaryFormat/ELF.h"
-#include "llvm/MC/MCAssembler.h"
 #include "llvm/MC/MCAsmBackend.h"
+#include "llvm/MC/MCAssembler.h"
 #include "llvm/MC/MCCodeEmitter.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCDwarf.h"
 #include "llvm/MC/MCELFStreamer.h"
 #include "llvm/MC/MCExpr.h"
 #include "llvm/MC/MCInstrInfo.h"
 #include "llvm/MC/MCObjectWriter.h"
 #include "llvm/MC/MCRegisterInfo.h"
+#include "llvm/MC/MCSectionXCOFF.h"
 #include "llvm/MC/MCStreamer.h"
 #include "llvm/MC/MCSubtargetInfo.h"
 #include "llvm/MC/MCSymbol.h"
 #include "llvm/MC/MCSymbolELF.h"
 #include "llvm/MC/MCSymbolXCOFF.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/CodeGen.h"
 #include "llvm/Support/ErrorHandling.h"

 
 public:
   PPCTargetAsmStreamer(MCStreamer &S, formatted_raw_ostream &OS)
       : PPCTargetStreamer(S), OS(OS) {}
 
   void emitTCEntry(const MCSymbol &S) override {
     if (const MCSymbolXCOFF *XSym = dyn_cast<MCSymbolXCOFF>(&S)) {
       MCSymbolXCOFF *TCSym =
-          cast<MCSymbolXCOFF>(Streamer.getContext().getOrCreateSymbol(
-              XSym->getSymbolTableName() + "[TC]"));
+          cast<MCSectionXCOFF>(Streamer.getCurrentSectionOnly())
+              ->getQualNameSymbol();
       OS << "\t.tc " << TCSym->getName() << "," << XSym->getName() << '\n';
 
       if (TCSym->hasRename())
         Streamer.emitXCOFFRenameDirective(TCSym, TCSym->getSymbolTableName());
       return;
     }
 
     OS << "\t.tc " << S.getName() << "[TC]," << S.getName() << '\n';

llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp

void PPCAIXAsmPrinter::emitEndOfAsmFile(Module &M) {
   if (TOCEntriesByteSize > 32767) {
     report_fatal_error("Handling of TOC entry displacement larger than 32767 "
                        "is not yet implemented.");
   }
 
   for (auto &I : TOC) {
     // Setup the csect for the current TC entry.
     MCSectionXCOFF *TCEntry = cast<MCSectionXCOFF>(
-        getObjFileLowering().getSectionForTOCEntry(I.first));
+        getObjFileLowering().getSectionForTOCEntry(I.first, TM));
     OutStreamer->SwitchSection(TCEntry);
 
     OutStreamer->emitLabel(I.second);
     if (TS != nullptr)
       TS->emitTCEntry(*I.first);
   }
 }
 

llvm/test/CodeGen/PowerPC/aix-lower-block-address.ll

 ; RUN: -code-model=small -stop-after=machine-cp < %s | FileCheck \
 ; RUN: --check-prefix=64SMALL-MIR %s
 
 ; RUN: llc -verify-machineinstrs -mcpu=pwr7 -mtriple powerpc64-ibm-aix-xcoff \
 ; RUN: -code-model=large -stop-after=machine-cp < %s | FileCheck \
 ; RUN: --check-prefix=64LARGE-MIR %s
 
 ; RUN: llc -verify-machineinstrs -mcpu=pwr7 -mtriple powerpc-ibm-aix-xcoff \
-; RUN: -code-model=small < %s | FileCheck --check-prefixes=32SMALL-ASM,CHECK %s
+; RUN: -code-model=small < %s | FileCheck --check-prefixes=32SMALL-ASM,SMALL-ASM %s
 
 ; RUN: llc -verify-machineinstrs -mcpu=pwr7 -mtriple powerpc-ibm-aix-xcoff \
-; RUN: -code-model=large < %s | FileCheck --check-prefixes=32LARGE-ASM,CHECK %s
+; RUN: -code-model=large < %s | FileCheck --check-prefixes=32LARGE-ASM,LARGE-ASM %s
 
 ; RUN: llc -verify-machineinstrs -mcpu=pwr7 -mtriple powerpc64-ibm-aix-xcoff \
-; RUN: -code-model=small < %s | FileCheck --check-prefixes=64SMALL-ASM,CHECK %s
+; RUN: -code-model=small < %s | FileCheck --check-prefixes=64SMALL-ASM,SMALL-ASM %s
 
 ; RUN: llc -verify-machineinstrs -mcpu=pwr7 -mtriple powerpc64-ibm-aix-xcoff \
-; RUN: -code-model=large < %s | FileCheck --check-prefixes=64LARGE-ASM,CHECK %s
+; RUN: -code-model=large < %s | FileCheck --check-prefixes=64LARGE-ASM,LARGE-ASM %s
 
 define void @foo() {
 entry:
   %tmp = alloca i64
   br label %__here
 
 __here:
   store i64 ptrtoint (i8* blockaddress(@foo, %__here) to i64), i64* %tmp

 ; 64SMALL-ASM:         ld [[REG1:[0-9]+]], L..C0(2)
 
 ; 64LARGE-ASM-LABEL: foo
 ; 64LARGE-ASM: .foo:
 ; 64LARGE-ASM: L..tmp0:
 ; 64LARGE-ASM:         addis [[REG1:[0-9]+]], L..C0@u(2)
 ; 64LARGE-ASM:         ld [[REG2:[0-9]+]], L..C0@l([[REG1]])
 
-; CHECK: .toc
-; CHECK: .tc L..tmp0[TC],L..tmp0
+; SMALL-ASM: .toc
+; SMALL-ASM: .tc L..tmp0[TC],L..tmp0
+
+; LARGE-ASM: .toc
+; LARGE-ASM: .tc L..tmp0[TE],L..tmp0

llvm/test/CodeGen/PowerPC/aix-lower-constant-pool-index.ll

 ; RUN: -code-model=small -stop-after=machine-cp < %s | FileCheck \
 ; RUN: --check-prefix=64SMALL-MIR %s
 
 ; RUN: llc -verify-machineinstrs -mcpu=pwr7 -mtriple powerpc64-ibm-aix-xcoff \
 ; RUN: -code-model=large -stop-after=machine-cp < %s | FileCheck \
 ; RUN: --check-prefix=64LARGE-MIR %s
 
 ; RUN: llc -verify-machineinstrs -mcpu=pwr7 -mtriple powerpc-ibm-aix-xcoff \
-; RUN: -code-model=small < %s | FileCheck --check-prefixes=32SMALL-ASM,CHECK %s
+; RUN: -code-model=small < %s | FileCheck --check-prefixes=32SMALL-ASM,SMALL-ASM %s
 
 ; RUN: llc -verify-machineinstrs -mcpu=pwr7 -mtriple powerpc-ibm-aix-xcoff \
-; RUN: -code-model=large < %s | FileCheck --check-prefixes=32LARGE-ASM,CHECK %s
+; RUN: -code-model=large < %s | FileCheck --check-prefixes=32LARGE-ASM,LARGE-ASM %s
 
 ; RUN: llc -verify-machineinstrs -mcpu=pwr7 -mtriple powerpc64-ibm-aix-xcoff \
-; RUN: -code-model=small < %s | FileCheck --check-prefixes=64SMALL-ASM,CHECK %s
+; RUN: -code-model=small < %s | FileCheck --check-prefixes=64SMALL-ASM,SMALL-ASM %s
 
 ; RUN: llc -verify-machineinstrs -mcpu=pwr7 -mtriple powerpc64-ibm-aix-xcoff \
-; RUN: -code-model=large < %s | FileCheck --check-prefixes=64LARGE-ASM,CHECK %s
+; RUN: -code-model=large < %s | FileCheck --check-prefixes=64LARGE-ASM,LARGE-ASM %s
 
 define float @test_float() {
 entry:
   ret float 5.500000e+00
 }
 
 ; 32SMALL-MIR: renamable $r[[REG1:[0-9]+]] = LWZtoc %const.0, $r2 :: (load 4 from got)
 ; 32SMALL-MIR: renamable $f[[REG2:[0-9]+]] = LFS 0, killed renamable $r[[REG1]] :: (load 4 from constant-pool)

 ; 64LARGE-ASM: L..CPI0_0:
 ; 64LARGE-ASM:         .vbyte 4, 0x40b00000
 ; 64LARGE-ASM: .test_float:
 ; 64LARGE-ASM:         addis [[REG1:[0-9]+]], L..C0@u(2)
 ; 64LARGE-ASM:         ld [[REG2:[0-9]+]], L..C0@l([[REG1]])
 ; 64LARGE-ASM:         lfs 1, 0([[REG2]])
 ; 64LARGE-ASM:         blr
 
-; CHECK: .toc
-; CHECK: .tc L..CPI0_0[TC],L..CPI0_0
+; SMALL-ASM: .toc
+; SMALL-ASM: .tc L..CPI0_0[TC],L..CPI0_0
+
+; LARGE-ASM: .toc
+; LARGE-ASM: .tc L..CPI0_0[TE],L..CPI0_0

llvm/test/CodeGen/PowerPC/aix-lower-jump-table.ll

 ; RUN: -code-model=small -stop-after=machine-cp < %s | FileCheck \
 ; RUN: --check-prefix=64SMALL-MIR %s
 
 ; RUN: llc -verify-machineinstrs -mcpu=pwr7 -mtriple powerpc64-ibm-aix-xcoff \
 ; RUN: -code-model=large -stop-after=machine-cp < %s | FileCheck \
 ; RUN: --check-prefix=64LARGE-MIR %s
 
 ; RUN: llc -mtriple powerpc-ibm-aix-xcoff -code-model=small < %s | FileCheck \
-; RUN: --check-prefixes=32SMALL-ASM,CHECK %s
+; RUN: --check-prefixes=32SMALL-ASM,SMALL-ASM %s
 
 ; RUN: llc -mtriple powerpc-ibm-aix-xcoff -code-model=large < %s | FileCheck \
-; RUN: --check-prefixes=32LARGE-ASM,CHECK %s
+; RUN: --check-prefixes=32LARGE-ASM,LARGE-ASM %s
 
 ; RUN: llc -mtriple powerpc64-ibm-aix-xcoff -code-model=small < %s | FileCheck \
-; RUN: --check-prefixes=64SMALL-ASM,CHECK %s
+; RUN: --check-prefixes=64SMALL-ASM,SMALL-ASM %s
 
 ; RUN: llc -mtriple powerpc64-ibm-aix-xcoff -code-model=large < %s | FileCheck \
-; RUN: --check-prefixes=64LARGE-ASM,CHECK %s
+; RUN: --check-prefixes=64LARGE-ASM,LARGE-ASM %s
 
   define i32 @jump_table(i32 %a) {
   entry:
     switch i32 %a, label %sw.epilog [
       i32 1, label %sw.bb
       i32 2, label %sw.bb1
       i32 3, label %sw.bb2
       i32 4, label %sw.bb3

 ; 64LARGE-ASM:      .csect .rodata[RO],2
 ; 64LARGE-ASM:      .align  2
 ; 64LARGE-ASM: L..JTI0_0:
 ; 64LARGE-ASM:      .vbyte  4, L..BB0_2-L..JTI0_0
 ; 64LARGE-ASM:      .vbyte  4, L..BB0_3-L..JTI0_0
 ; 64LARGE-ASM:      .vbyte  4, L..BB0_4-L..JTI0_0
 ; 64LARGE-ASM:      .vbyte  4, L..BB0_5-L..JTI0_0
 
-; CHECK: .toc
-; CHECK: .tc L..JTI0_0[TC],L..JTI0_0
+; SMALL-ASM: .toc
+; SMALL-ASM: .tc L..JTI0_0[TC],L..JTI0_0
+
+; LARGE-ASM: .toc
+; LARGE-ASM: .tc L..JTI0_0[TE],L..JTI0_0

llvm/test/CodeGen/PowerPC/lower-globaladdr32-aix-asm.ll

 ; RUN: llc -verify-machineinstrs -mcpu=pwr7 -mtriple powerpc-ibm-aix-xcoff \
-; RUN: -code-model=small < %s | FileCheck %s --check-prefixes=CHECK,SMALL
+; RUN: -code-model=small < %s | FileCheck %s --check-prefix=SMALL
 
 ; RUN: llc -verify-machineinstrs -mcpu=pwr7 -mtriple powerpc-ibm-aix-xcoff \
-; RUN: -code-model=large < %s | FileCheck %s --check-prefixes=CHECK,LARGE
+; RUN: -code-model=large < %s | FileCheck %s --check-prefix=LARGE
 
 @a = common global i32 0
 
 define i32 @test_load() {
 entry:
   %0 = load i32, i32* @a
   ret i32 %0
 }

 ; SMALL: blr
 
 ; LARGE-LABEL: .test_store:{{$}}
 ; LARGE: addis [[REG1:[0-9]+]], L..C1@u(2)
 ; LARGE: lwz [[REG2:[0-9]+]], L..C1@l([[REG1]])
 ; LARGE: stw [[REG3:[0-9]+]], 0([[REG2]])
 ; LARGE: blr
 
-; CHECK: .tc a[TC],a
-; CHECK: .tc b[TC],b
+; SMALL: .tc a[TC],a
+; SMALL: .tc b[TC],b
+
+; LARGE: .tc a[TE],a
+; LARGE: .tc b[TE],b

llvm/test/CodeGen/PowerPC/lower-globaladdr64-aix-asm.ll

 ; RUN: llc -verify-machineinstrs -mcpu=pwr7 -mtriple powerpc64-ibm-aix-xcoff \
-; RUN: -code-model=small < %s | FileCheck %s --check-prefixes=CHECK,SMALL
+; RUN: -code-model=small < %s | FileCheck %s --check-prefix=SMALL
 
 ; RUN: llc -verify-machineinstrs -mcpu=pwr7 -mtriple powerpc64-ibm-aix-xcoff \
-; RUN: -code-model=large < %s | FileCheck %s --check-prefixes=CHECK,LARGE
+; RUN: -code-model=large < %s | FileCheck %s --check-prefix=LARGE
 
 @a = common global i32 0
 
 define zeroext i32 @test_load() {
 entry:
   %0 = load i32, i32* @a
   ret i32 %0
 }

 ; SMALL: blr
 
 ; LARGE-LABEL: .test_store:{{$}}
 ; LARGE: addis [[REG1:[0-9]+]], L..C1@u(2)
 ; LARGE: ld [[REG2:[0-9]+]], L..C1@l([[REG1]])
 ; LARGE: stw [[REG3:[0-9]+]], 0([[REG2]])
 ; LARGE: blr
 
-; CHECK: .tc a[TC],a
-; CHECK: .tc b[TC],b
+; SMALL: .tc a[TC],a
+; SMALL: .tc b[TC],b
+
+; LARGE: .tc a[TE],a
+; LARGE: .tc b[TE],b