RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-10-19 02:52:53 +02:00
Code Issues Projects Releases Wiki Activity
ad99b95580
llvm-mirror/lib/Target/Hexagon/HexagonTargetObjectFile.cpp
Chandler Carruth ae65e281f3 Update the file headers across all of the LLVM projects in the monorepo 
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00

462 lines
17 KiB
C++
Raw Blame History

//===-- 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/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);
InitializeELF(TM.Options.UseInitArray);
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->getType();
if (PointerType *PT = dyn_cast<PointerType>(GType))
GType = PT->getElementType();
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::VectorTyID: {
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::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->getType()->getElementType();
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);
}
Reference in New Issue View Git Blame Copy Permalink