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llvm-project/llvm/lib/Target/X86/X86Subtarget.cpp

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//===-- X86Subtarget.cpp - X86 Subtarget Information ----------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the X86 specific subclass of TargetSubtargetInfo.
//
//===----------------------------------------------------------------------===//
#include "X86Subtarget.h"
#include "X86InstrInfo.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/Host.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#if defined(_MSC_VER)
#include <intrin.h>
#endif
using namespace llvm;
#define DEBUG_TYPE "subtarget"
#define GET_SUBTARGETINFO_TARGET_DESC
#define GET_SUBTARGETINFO_CTOR
#include "X86GenSubtargetInfo.inc"
// Temporary option to control early if-conversion for x86 while adding machine
// models.
static cl::opt<bool>
X86EarlyIfConv("x86-early-ifcvt", cl::Hidden,
cl::desc("Enable early if-conversion on X86"));
/// ClassifyBlockAddressReference - Classify a blockaddress reference for the
/// current subtarget according to how we should reference it in a non-pcrel
/// context.
unsigned char X86Subtarget::ClassifyBlockAddressReference() const {
if (isPICStyleGOT()) // 32-bit ELF targets.
return X86II::MO_GOTOFF;
if (isPICStyleStubPIC()) // Darwin/32 in PIC mode.
return X86II::MO_PIC_BASE_OFFSET;
// Direct static reference to label.
return X86II::MO_NO_FLAG;
}
/// ClassifyGlobalReference - Classify a global variable reference for the
/// current subtarget according to how we should reference it in a non-pcrel
/// context.
unsigned char X86Subtarget::
ClassifyGlobalReference(const GlobalValue *GV, const TargetMachine &TM) const {
// DLLImport only exists on windows, it is implemented as a load from a
// DLLIMPORT stub.
if (GV->hasDLLImportStorageClass())
return X86II::MO_DLLIMPORT;
// Determine whether this is a reference to a definition or a declaration.
// Materializable GVs (in JIT lazy compilation mode) do not require an extra
// load from stub.
bool isDecl = GV->hasAvailableExternallyLinkage();
if (GV->isDeclaration() && !GV->isMaterializable())
isDecl = true;
// X86-64 in PIC mode.
if (isPICStyleRIPRel()) {
// Large model never uses stubs.
if (TM.getCodeModel() == CodeModel::Large)
return X86II::MO_NO_FLAG;
if (isTargetDarwin()) {
// If symbol visibility is hidden, the extra load is not needed if
// target is x86-64 or the symbol is definitely defined in the current
// translation unit.
if (GV->hasDefaultVisibility() &&
(isDecl || GV->isWeakForLinker()))
return X86II::MO_GOTPCREL;
} else if (!isTargetWin64()) {
assert(isTargetELF() && "Unknown rip-relative target");
// Extra load is needed for all externally visible.
if (!GV->hasLocalLinkage() && GV->hasDefaultVisibility())
return X86II::MO_GOTPCREL;
}
return X86II::MO_NO_FLAG;
}
if (isPICStyleGOT()) { // 32-bit ELF targets.
// Extra load is needed for all externally visible.
if (GV->hasLocalLinkage() || GV->hasHiddenVisibility())
return X86II::MO_GOTOFF;
return X86II::MO_GOT;
}
if (isPICStyleStubPIC()) { // Darwin/32 in PIC mode.
// Determine whether we have a stub reference and/or whether the reference
// is relative to the PIC base or not.
// If this is a strong reference to a definition, it is definitely not
// through a stub.
if (!isDecl && !GV->isWeakForLinker())
return X86II::MO_PIC_BASE_OFFSET;
// Unless we have a symbol with hidden visibility, we have to go through a
// normal $non_lazy_ptr stub because this symbol might be resolved late.
if (!GV->hasHiddenVisibility()) // Non-hidden $non_lazy_ptr reference.
return X86II::MO_DARWIN_NONLAZY_PIC_BASE;
// If symbol visibility is hidden, we have a stub for common symbol
// references and external declarations.
if (isDecl || GV->hasCommonLinkage()) {
// Hidden $non_lazy_ptr reference.
return X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE;
}
// Otherwise, no stub.
return X86II::MO_PIC_BASE_OFFSET;
}
if (isPICStyleStubNoDynamic()) { // Darwin/32 in -mdynamic-no-pic mode.
// Determine whether we have a stub reference.
// If this is a strong reference to a definition, it is definitely not
// through a stub.
if (!isDecl && !GV->isWeakForLinker())
return X86II::MO_NO_FLAG;
// Unless we have a symbol with hidden visibility, we have to go through a
// normal $non_lazy_ptr stub because this symbol might be resolved late.
if (!GV->hasHiddenVisibility()) // Non-hidden $non_lazy_ptr reference.
return X86II::MO_DARWIN_NONLAZY;
// Otherwise, no stub.
return X86II::MO_NO_FLAG;
}
// Direct static reference to global.
return X86II::MO_NO_FLAG;
}
/// getBZeroEntry - This function returns the name of a function which has an
/// interface like the non-standard bzero function, if such a function exists on
/// the current subtarget and it is considered prefereable over memset with zero
/// passed as the second argument. Otherwise it returns null.
const char *X86Subtarget::getBZeroEntry() const {
// Darwin 10 has a __bzero entry point for this purpose.
if (getTargetTriple().isMacOSX() &&
!getTargetTriple().isMacOSXVersionLT(10, 6))
return "__bzero";
return nullptr;
}
bool X86Subtarget::hasSinCos() const {
return getTargetTriple().isMacOSX() &&
!getTargetTriple().isMacOSXVersionLT(10, 9) &&
is64Bit();
}
/// IsLegalToCallImmediateAddr - Return true if the subtarget allows calls
/// to immediate address.
bool X86Subtarget::IsLegalToCallImmediateAddr(const TargetMachine &TM) const {
// FIXME: I386 PE/COFF supports PC relative calls using IMAGE_REL_I386_REL32
// but WinCOFFObjectWriter::RecordRelocation cannot emit them. Once it does,
// the following check for Win32 should be removed.
if (In64BitMode || isTargetWin32())
return false;
return isTargetELF() || TM.getRelocationModel() == Reloc::Static;
}
void X86Subtarget::resetSubtargetFeatures(const MachineFunction *MF) {
AttributeSet FnAttrs = MF->getFunction()->getAttributes();
Attribute CPUAttr =
FnAttrs.getAttribute(AttributeSet::FunctionIndex, "target-cpu");
Attribute FSAttr =
FnAttrs.getAttribute(AttributeSet::FunctionIndex, "target-features");
std::string CPU =
!CPUAttr.hasAttribute(Attribute::None) ? CPUAttr.getValueAsString() : "";
std::string FS =
!FSAttr.hasAttribute(Attribute::None) ? FSAttr.getValueAsString() : "";
if (!FS.empty()) {
initializeEnvironment();
resetSubtargetFeatures(CPU, FS);
}
}
void X86Subtarget::resetSubtargetFeatures(StringRef CPU, StringRef FS) {
std::string CPUName = CPU;
if (CPUName.empty())
CPUName = "generic";
// Make sure 64-bit features are available in 64-bit mode. (But make sure
// SSE2 can be turned off explicitly.)
std::string FullFS = FS;
if (In64BitMode) {
if (!FullFS.empty())
FullFS = "+64bit,+sse2," + FullFS;
else
FullFS = "+64bit,+sse2";
}
// If feature string is not empty, parse features string.
ParseSubtargetFeatures(CPUName, FullFS);
// Make sure the right MCSchedModel is used.
InitCPUSchedModel(CPUName);
InstrItins = getInstrItineraryForCPU(CPUName);
// It's important to keep the MCSubtargetInfo feature bits in sync with
// target data structure which is shared with MC code emitter, etc.
if (In64BitMode)
ToggleFeature(X86::Mode64Bit);
else if (In32BitMode)
ToggleFeature(X86::Mode32Bit);
else if (In16BitMode)
ToggleFeature(X86::Mode16Bit);
else
llvm_unreachable("Not 16-bit, 32-bit or 64-bit mode!");
DEBUG(dbgs() << "Subtarget features: SSELevel " << X86SSELevel
<< ", 3DNowLevel " << X863DNowLevel
<< ", 64bit " << HasX86_64 << "\n");
assert((!In64BitMode || HasX86_64) &&
"64-bit code requested on a subtarget that doesn't support it!");
// Stack alignment is 16 bytes on Darwin, Linux and Solaris (both
// 32 and 64 bit) and for all 64-bit targets.
if (StackAlignOverride)
stackAlignment = StackAlignOverride;
else if (isTargetDarwin() || isTargetLinux() || isTargetSolaris() ||
In64BitMode)
stackAlignment = 16;
}
void X86Subtarget::initializeEnvironment() {
X86SSELevel = NoMMXSSE;
X863DNowLevel = NoThreeDNow;
HasCMov = false;
HasX86_64 = false;
HasPOPCNT = false;
HasSSE4A = false;
HasAES = false;
HasPCLMUL = false;
HasFMA = false;
HasFMA4 = false;
HasXOP = false;
HasTBM = false;
HasMOVBE = false;
HasRDRAND = false;
HasF16C = false;
HasFSGSBase = false;
HasLZCNT = false;
HasBMI = false;
HasBMI2 = false;
HasRTM = false;
HasHLE = false;
HasERI = false;
HasCDI = false;
HasPFI = false;
HasDQI = false;
HasBWI = false;
HasVLX = false;
HasADX = false;
HasSHA = false;
HasPRFCHW = false;
HasRDSEED = false;
IsBTMemSlow = false;
IsSHLDSlow = false;
IsUAMemFast = false;
HasVectorUAMem = false;
HasCmpxchg16b = false;
UseLeaForSP = false;
HasSlowDivide = false;
PadShortFunctions = false;
CallRegIndirect = false;
LEAUsesAG = false;
SlowLEA = false;
SlowIncDec = false;
stackAlignment = 4;
// FIXME: this is a known good value for Yonah. How about others?
MaxInlineSizeThreshold = 128;
}
static std::string computeDataLayout(const X86Subtarget &ST) {
// X86 is little endian
std::string Ret = "e";
Ret += DataLayout::getManglingComponent(ST.getTargetTriple());
// X86 and x32 have 32 bit pointers.
if (ST.isTarget64BitILP32() || !ST.is64Bit())
Ret += "-p:32:32";
// Some ABIs align 64 bit integers and doubles to 64 bits, others to 32.
if (ST.is64Bit() || ST.isOSWindows() || ST.isTargetNaCl())
Ret += "-i64:64";
else
Ret += "-f64:32:64";
// Some ABIs align long double to 128 bits, others to 32.
if (ST.isTargetNaCl())
; // No f80
else if (ST.is64Bit() || ST.isTargetDarwin())
Ret += "-f80:128";
else
Ret += "-f80:32";
// The registers can hold 8, 16, 32 or, in x86-64, 64 bits.
if (ST.is64Bit())
Ret += "-n8:16:32:64";
else
Ret += "-n8:16:32";
// The stack is aligned to 32 bits on some ABIs and 128 bits on others.
if (!ST.is64Bit() && ST.isOSWindows())
Ret += "-S32";
else
Ret += "-S128";
return Ret;
}
X86Subtarget &X86Subtarget::initializeSubtargetDependencies(StringRef CPU,
StringRef FS) {
initializeEnvironment();
resetSubtargetFeatures(CPU, FS);
return *this;
}
X86Subtarget::X86Subtarget(const std::string &TT, const std::string &CPU,
const std::string &FS, X86TargetMachine &TM,
unsigned StackAlignOverride)
: X86GenSubtargetInfo(TT, CPU, FS), X86ProcFamily(Others),
PICStyle(PICStyles::None), TargetTriple(TT),
StackAlignOverride(StackAlignOverride),
In64BitMode(TargetTriple.getArch() == Triple::x86_64),
In32BitMode(TargetTriple.getArch() == Triple::x86 &&
TargetTriple.getEnvironment() != Triple::CODE16),
In16BitMode(TargetTriple.getArch() == Triple::x86 &&
TargetTriple.getEnvironment() == Triple::CODE16),
DL(computeDataLayout(*this)), TSInfo(DL),
InstrInfo(initializeSubtargetDependencies(CPU, FS)), TLInfo(TM),
FrameLowering(TargetFrameLowering::StackGrowsDown, getStackAlignment(),
is64Bit() ? -8 : -4),
JITInfo(hasSSE1()) {}
bool X86Subtarget::enableEarlyIfConversion() const {
return hasCMov() && X86EarlyIfConv;
}
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