1 files changed, 460 insertions, 0 deletions
diff --git a/contrib/llvm-project/llvm/lib/Target/Hexagon/HexagonTargetObjectFile.cpp b/contrib/llvm-project/llvm/lib/Target/Hexagon/HexagonTargetObjectFile.cpp
new file mode 100644
index 000000000000..cfc8ed813c92
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+++ b/contrib/llvm-project/llvm/lib/Target/Hexagon/HexagonTargetObjectFile.cpp
@@ -0,0 +1,460 @@
+//===-- HexagonTargetObjectFile.cpp ---------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains the declarations of the HexagonTargetAsmInfo properties.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "hexagon-sdata"
+
+#include "HexagonTargetObjectFile.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/BinaryFormat/ELF.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/GlobalObject.h"
+#include "llvm/IR/GlobalValue.h"
+#include "llvm/IR/GlobalVariable.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Type.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/SectionKind.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetMachine.h"
+
+using namespace llvm;
+
+static cl::opt<unsigned> SmallDataThreshold("hexagon-small-data-threshold",
+  cl::init(8), cl::Hidden,
+  cl::desc("The maximum size of an object in the sdata section"));
+
+static cl::opt<bool> NoSmallDataSorting("mno-sort-sda", cl::init(false),
+  cl::Hidden, cl::desc("Disable small data sections sorting"));
+
+static cl::opt<bool> StaticsInSData("hexagon-statics-in-small-data",
+  cl::init(false), cl::Hidden, cl::ZeroOrMore,
+  cl::desc("Allow static variables in .sdata"));
+
+static cl::opt<bool> TraceGVPlacement("trace-gv-placement",
+  cl::Hidden, cl::init(false),
+  cl::desc("Trace global value placement"));
+
+static cl::opt<bool>
+    EmitJtInText("hexagon-emit-jt-text", cl::Hidden, cl::init(false),
+                 cl::desc("Emit hexagon jump tables in function section"));
+
+static cl::opt<bool>
+    EmitLutInText("hexagon-emit-lut-text", cl::Hidden, cl::init(false),
+                 cl::desc("Emit hexagon lookup tables in function section"));
+
+// TraceGVPlacement controls messages for all builds. For builds with assertions
+// (debug or release), messages are also controlled by the usual debug flags
+// (e.g. -debug and -debug-only=globallayout)
+#define TRACE_TO(s, X) s << X
+#ifdef NDEBUG
+#define TRACE(X)                                                               \
+  do {                                                                         \
+    if (TraceGVPlacement) {                                                    \
+      TRACE_TO(errs(), X);                                                     \
+    }                                                                          \
+  } while (false)
+#else
+#define TRACE(X)                                                               \
+  do {                                                                         \
+    if (TraceGVPlacement) {                                                    \
+      TRACE_TO(errs(), X);                                                     \
+    } else {                                                                   \
+      LLVM_DEBUG(TRACE_TO(dbgs(), X));                                         \
+    }                                                                          \
+  } while (false)
+#endif
+
+// Returns true if the section name is such that the symbol will be put
+// in a small data section.
+// For instance, global variables with section attributes such as ".sdata"
+// ".sdata.*", ".sbss", and ".sbss.*" will go into small data.
+static bool isSmallDataSection(StringRef Sec) {
+  // sectionName is either ".sdata" or ".sbss". Looking for an exact match
+  // obviates the need for checks for section names such as ".sdatafoo".
+  if (Sec.equals(".sdata") || Sec.equals(".sbss") || Sec.equals(".scommon"))
+    return true;
+  // If either ".sdata." or ".sbss." is a substring of the section name
+  // then put the symbol in small data.
+  return Sec.find(".sdata.") != StringRef::npos ||
+         Sec.find(".sbss.") != StringRef::npos ||
+         Sec.find(".scommon.") != StringRef::npos;
+}
+
+static const char *getSectionSuffixForSize(unsigned Size) {
+  switch (Size) {
+  default:
+    return "";
+  case 1:
+    return ".1";
+  case 2:
+    return ".2";
+  case 4:
+    return ".4";
+  case 8:
+    return ".8";
+  }
+}
+
+void HexagonTargetObjectFile::Initialize(MCContext &Ctx,
+      const TargetMachine &TM) {
+  TargetLoweringObjectFileELF::Initialize(Ctx, TM);
+
+  SmallDataSection =
+    getContext().getELFSection(".sdata", ELF::SHT_PROGBITS,
+                               ELF::SHF_WRITE | ELF::SHF_ALLOC |
+                               ELF::SHF_HEX_GPREL);
+  SmallBSSSection =
+    getContext().getELFSection(".sbss", ELF::SHT_NOBITS,
+                               ELF::SHF_WRITE | ELF::SHF_ALLOC |
+                               ELF::SHF_HEX_GPREL);
+}
+
+MCSection *HexagonTargetObjectFile::SelectSectionForGlobal(
+    const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
+  TRACE("[SelectSectionForGlobal] GO(" << GO->getName() << ") ");
+  TRACE("input section(" << GO->getSection() << ") ");
+
+  TRACE((GO->hasPrivateLinkage() ? "private_linkage " : "")
+         << (GO->hasLocalLinkage() ? "local_linkage " : "")
+         << (GO->hasInternalLinkage() ? "internal " : "")
+         << (GO->hasExternalLinkage() ? "external " : "")
+         << (GO->hasCommonLinkage() ? "common_linkage " : "")
+         << (GO->hasCommonLinkage() ? "common " : "" )
+         << (Kind.isCommon() ? "kind_common " : "" )
+         << (Kind.isBSS() ? "kind_bss " : "" )
+         << (Kind.isBSSLocal() ? "kind_bss_local " : "" ));
+
+  // If the lookup table is used by more than one function, do not place
+  // it in text section.
+  if (EmitLutInText && GO->getName().startswith("switch.table")) {
+    if (const Function *Fn = getLutUsedFunction(GO))
+      return selectSectionForLookupTable(GO, TM, Fn);
+  }
+
+  if (isGlobalInSmallSection(GO, TM))
+    return selectSmallSectionForGlobal(GO, Kind, TM);
+
+  if (Kind.isCommon()) {
+    // This is purely for LTO+Linker Script because commons don't really have a
+    // section. However, the BitcodeSectionWriter pass will query for the
+    // sections of commons (and the linker expects us to know their section) so
+    // we'll return one here.
+    return BSSSection;
+  }
+
+  TRACE("default_ELF_section\n");
+  // Otherwise, we work the same as ELF.
+  return TargetLoweringObjectFileELF::SelectSectionForGlobal(GO, Kind, TM);
+}
+
+MCSection *HexagonTargetObjectFile::getExplicitSectionGlobal(
+    const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
+  TRACE("[getExplicitSectionGlobal] GO(" << GO->getName() << ") from("
+        << GO->getSection() << ") ");
+  TRACE((GO->hasPrivateLinkage() ? "private_linkage " : "")
+         << (GO->hasLocalLinkage() ? "local_linkage " : "")
+         << (GO->hasInternalLinkage() ? "internal " : "")
+         << (GO->hasExternalLinkage() ? "external " : "")
+         << (GO->hasCommonLinkage() ? "common_linkage " : "")
+         << (GO->hasCommonLinkage() ? "common " : "" )
+         << (Kind.isCommon() ? "kind_common " : "" )
+         << (Kind.isBSS() ? "kind_bss " : "" )
+         << (Kind.isBSSLocal() ? "kind_bss_local " : "" ));
+
+  if (GO->hasSection()) {
+    StringRef Section = GO->getSection();
+    if (Section.find(".access.text.group") != StringRef::npos)
+      return getContext().getELFSection(GO->getSection(), ELF::SHT_PROGBITS,
+                                        ELF::SHF_ALLOC | ELF::SHF_EXECINSTR);
+    if (Section.find(".access.data.group") != StringRef::npos)
+      return getContext().getELFSection(GO->getSection(), ELF::SHT_PROGBITS,
+                                        ELF::SHF_WRITE | ELF::SHF_ALLOC);
+  }
+
+  if (isGlobalInSmallSection(GO, TM))
+    return selectSmallSectionForGlobal(GO, Kind, TM);
+
+  // Otherwise, we work the same as ELF.
+  TRACE("default_ELF_section\n");
+  return TargetLoweringObjectFileELF::getExplicitSectionGlobal(GO, Kind, TM);
+}
+
+/// Return true if this global value should be placed into small data/bss
+/// section.
+bool HexagonTargetObjectFile::isGlobalInSmallSection(const GlobalObject *GO,
+      const TargetMachine &TM) const {
+  bool HaveSData = isSmallDataEnabled(TM);
+  if (!HaveSData)
+    LLVM_DEBUG(dbgs() << "Small-data allocation is disabled, but symbols "
+                         "may have explicit section assignments...\n");
+  // Only global variables, not functions.
+  LLVM_DEBUG(dbgs() << "Checking if value is in small-data, -G"
+                    << SmallDataThreshold << ": \"" << GO->getName() << "\": ");
+  const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GO);
+  if (!GVar) {
+    LLVM_DEBUG(dbgs() << "no, not a global variable\n");
+    return false;
+  }
+
+  // Globals with external linkage that have an original section set must be
+  // emitted to that section, regardless of whether we would put them into
+  // small data or not. This is how we can support mixing -G0/-G8 in LTO.
+  if (GVar->hasSection()) {
+    bool IsSmall = isSmallDataSection(GVar->getSection());
+    LLVM_DEBUG(dbgs() << (IsSmall ? "yes" : "no")
+                      << ", has section: " << GVar->getSection() << '\n');
+    return IsSmall;
+  }
+
+  // If sdata is disabled, stop the checks here.
+  if (!HaveSData) {
+    LLVM_DEBUG(dbgs() << "no, small-data allocation is disabled\n");
+    return false;
+  }
+
+  if (GVar->isConstant()) {
+    LLVM_DEBUG(dbgs() << "no, is a constant\n");
+    return false;
+  }
+
+  bool IsLocal = GVar->hasLocalLinkage();
+  if (!StaticsInSData && IsLocal) {
+    LLVM_DEBUG(dbgs() << "no, is static\n");
+    return false;
+  }
+
+  Type *GType = GVar->getValueType();
+  if (isa<ArrayType>(GType)) {
+    LLVM_DEBUG(dbgs() << "no, is an array\n");
+    return false;
+  }
+
+  // If the type is a struct with no body provided, treat is conservatively.
+  // There cannot be actual definitions of object of such a type in this CU
+  // (only references), so assuming that they are not in sdata is safe. If
+  // these objects end up in the sdata, the references will still be valid.
+  if (StructType *ST = dyn_cast<StructType>(GType)) {
+    if (ST->isOpaque()) {
+      LLVM_DEBUG(dbgs() << "no, has opaque type\n");
+      return false;
+    }
+  }
+
+  unsigned Size = GVar->getParent()->getDataLayout().getTypeAllocSize(GType);
+  if (Size == 0) {
+    LLVM_DEBUG(dbgs() << "no, has size 0\n");
+    return false;
+  }
+  if (Size > SmallDataThreshold) {
+    LLVM_DEBUG(dbgs() << "no, size exceeds sdata threshold: " << Size << '\n');
+    return false;
+  }
+
+  LLVM_DEBUG(dbgs() << "yes\n");
+  return true;
+}
+
+bool HexagonTargetObjectFile::isSmallDataEnabled(const TargetMachine &TM)
+    const {
+  return SmallDataThreshold > 0 && !TM.isPositionIndependent();
+}
+
+unsigned HexagonTargetObjectFile::getSmallDataSize() const {
+  return SmallDataThreshold;
+}
+
+bool HexagonTargetObjectFile::shouldPutJumpTableInFunctionSection(
+    bool UsesLabelDifference, const Function &F) const {
+  return EmitJtInText;
+}
+
+/// Descends any type down to "elementary" components,
+/// discovering the smallest addressable one.
+/// If zero is returned, declaration will not be modified.
+unsigned HexagonTargetObjectFile::getSmallestAddressableSize(const Type *Ty,
+      const GlobalValue *GV, const TargetMachine &TM) const {
+  // Assign the smallest element access size to the highest
+  // value which assembler can handle.
+  unsigned SmallestElement = 8;
+
+  if (!Ty)
+    return 0;
+  switch (Ty->getTypeID()) {
+  case Type::StructTyID: {
+    const StructType *STy = cast<const StructType>(Ty);
+    for (auto &E : STy->elements()) {
+      unsigned AtomicSize = getSmallestAddressableSize(E, GV, TM);
+      if (AtomicSize < SmallestElement)
+        SmallestElement = AtomicSize;
+    }
+    return (STy->getNumElements() == 0) ? 0 : SmallestElement;
+  }
+  case Type::ArrayTyID: {
+    const ArrayType *ATy = cast<const ArrayType>(Ty);
+    return getSmallestAddressableSize(ATy->getElementType(), GV, TM);
+  }
+  case Type::FixedVectorTyID:
+  case Type::ScalableVectorTyID: {
+    const VectorType *PTy = cast<const VectorType>(Ty);
+    return getSmallestAddressableSize(PTy->getElementType(), GV, TM);
+  }
+  case Type::PointerTyID:
+  case Type::HalfTyID:
+  case Type::FloatTyID:
+  case Type::DoubleTyID:
+  case Type::IntegerTyID: {
+    const DataLayout &DL = GV->getParent()->getDataLayout();
+    // It is unfortunate that DL's function take non-const Type*.
+    return DL.getTypeAllocSize(const_cast<Type*>(Ty));
+  }
+  case Type::FunctionTyID:
+  case Type::VoidTyID:
+  case Type::BFloatTyID:
+  case Type::X86_FP80TyID:
+  case Type::FP128TyID:
+  case Type::PPC_FP128TyID:
+  case Type::LabelTyID:
+  case Type::MetadataTyID:
+  case Type::X86_MMXTyID:
+  case Type::TokenTyID:
+    return 0;
+  }
+
+  return 0;
+}
+
+MCSection *HexagonTargetObjectFile::selectSmallSectionForGlobal(
+    const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
+  const Type *GTy = GO->getValueType();
+  unsigned Size = getSmallestAddressableSize(GTy, GO, TM);
+
+  // If we have -ffunction-section or -fdata-section then we should emit the
+  // global value to a unique section specifically for it... even for sdata.
+  bool EmitUniquedSection = TM.getDataSections();
+
+  TRACE("Small data. Size(" << Size << ")");
+  // Handle Small Section classification here.
+  if (Kind.isBSS() || Kind.isBSSLocal()) {
+    // If -mno-sort-sda is not set, find out smallest accessible entity in
+    // declaration and add it to the section name string.
+    // Note. It does not track the actual usage of the value, only its de-
+    // claration. Also, compiler adds explicit pad fields to some struct
+    // declarations - they are currently counted towards smallest addres-
+    // sable entity.
+    if (NoSmallDataSorting) {
+      TRACE(" default sbss\n");
+      return SmallBSSSection;
+    }
+
+    StringRef Prefix(".sbss");
+    SmallString<128> Name(Prefix);
+    Name.append(getSectionSuffixForSize(Size));
+
+    if (EmitUniquedSection) {
+      Name.append(".");
+      Name.append(GO->getName());
+    }
+    TRACE(" unique sbss(" << Name << ")\n");
+    return getContext().getELFSection(Name.str(), ELF::SHT_NOBITS,
+                ELF::SHF_WRITE | ELF::SHF_ALLOC | ELF::SHF_HEX_GPREL);
+  }
+
+  if (Kind.isCommon()) {
+    // This is purely for LTO+Linker Script because commons don't really have a
+    // section. However, the BitcodeSectionWriter pass will query for the
+    // sections of commons (and the linker expects us to know their section) so
+    // we'll return one here.
+    if (NoSmallDataSorting)
+      return BSSSection;
+
+    Twine Name = Twine(".scommon") + getSectionSuffixForSize(Size);
+    TRACE(" small COMMON (" << Name << ")\n");
+
+    return getContext().getELFSection(Name.str(), ELF::SHT_NOBITS,
+                                      ELF::SHF_WRITE | ELF::SHF_ALLOC |
+                                      ELF::SHF_HEX_GPREL);
+  }
+
+  // We could have changed sdata object to a constant... in this
+  // case the Kind could be wrong for it.
+  if (Kind.isMergeableConst()) {
+    TRACE(" const_object_as_data ");
+    const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GO);
+    if (GVar->hasSection() && isSmallDataSection(GVar->getSection()))
+      Kind = SectionKind::getData();
+  }
+
+  if (Kind.isData()) {
+    if (NoSmallDataSorting) {
+      TRACE(" default sdata\n");
+      return SmallDataSection;
+    }
+
+    StringRef Prefix(".sdata");
+    SmallString<128> Name(Prefix);
+    Name.append(getSectionSuffixForSize(Size));
+
+    if (EmitUniquedSection) {
+      Name.append(".");
+      Name.append(GO->getName());
+    }
+    TRACE(" unique sdata(" << Name << ")\n");
+    return getContext().getELFSection(Name.str(), ELF::SHT_PROGBITS,
+                ELF::SHF_WRITE | ELF::SHF_ALLOC | ELF::SHF_HEX_GPREL);
+  }
+
+  TRACE("default ELF section\n");
+  // Otherwise, we work the same as ELF.
+  return TargetLoweringObjectFileELF::SelectSectionForGlobal(GO, Kind, TM);
+}
+
+// Return the function that uses the lookup table. If there are more
+// than one live function that uses this look table, bail out and place
+// the lookup table in default section.
+const Function *
+HexagonTargetObjectFile::getLutUsedFunction(const GlobalObject *GO) const {
+  const Function *ReturnFn = nullptr;
+  for (auto U : GO->users()) {
+    // validate each instance of user to be a live function.
+    auto *I = dyn_cast<Instruction>(U);
+    if (!I)
+      continue;
+    auto *Bb = I->getParent();
+    if (!Bb)
+      continue;
+    auto *UserFn = Bb->getParent();
+    if (!ReturnFn)
+      ReturnFn = UserFn;
+    else if (ReturnFn != UserFn)
+      return nullptr;
+  }
+  return ReturnFn;
+}
+
+MCSection *HexagonTargetObjectFile::selectSectionForLookupTable(
+    const GlobalObject *GO, const TargetMachine &TM, const Function *Fn) const {
+
+  SectionKind Kind = SectionKind::getText();
+  // If the function has explicit section, place the lookup table in this
+  // explicit section.
+  if (Fn->hasSection())
+    return getExplicitSectionGlobal(Fn, Kind, TM);
+
+  const auto *FuncObj = dyn_cast<GlobalObject>(Fn);
+  return SelectSectionForGlobal(FuncObj, Kind, TM);
+}