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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.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "subtarget"
#include "X86Subtarget.h"
#include "X86InstrInfo.h"
#include "llvm/GlobalValue.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Support/Host.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/ADT/SmallVector.h"
#define GET_SUBTARGETINFO_TARGET_DESC
#define GET_SUBTARGETINFO_CTOR
#include "X86GenSubtargetInfo.inc"
using namespace llvm;
#if defined(_MSC_VER)
#include <intrin.h>
#endif
/// 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->hasDLLImportLinkage())
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 0;
}
/// IsLegalToCallImmediateAddr - Return true if the subtarget allows calls
/// to immediate address.
bool X86Subtarget::IsLegalToCallImmediateAddr(const TargetMachine &TM) const {
if (In64BitMode)
return false;
return isTargetELF() || TM.getRelocationModel() == Reloc::Static;
}
/// getSpecialAddressLatency - For targets where it is beneficial to
/// backschedule instructions that compute addresses, return a value
/// indicating the number of scheduling cycles of backscheduling that
/// should be attempted.
unsigned X86Subtarget::getSpecialAddressLatency() const {
// For x86 out-of-order targets, back-schedule address computations so
// that loads and stores aren't blocked.
// This value was chosen arbitrarily.
return 200;
}
void X86Subtarget::AutoDetectSubtargetFeatures() {
unsigned EAX = 0, EBX = 0, ECX = 0, EDX = 0;
unsigned MaxLevel;
union {
unsigned u[3];
char c[12];
} text;
if (X86_MC::GetCpuIDAndInfo(0, &MaxLevel, text.u+0, text.u+2, text.u+1) ||
MaxLevel < 1)
return;
X86_MC::GetCpuIDAndInfo(0x1, &EAX, &EBX, &ECX, &EDX);
if ((EDX >> 15) & 1) { HasCMov = true; ToggleFeature(X86::FeatureCMOV); }
if ((EDX >> 23) & 1) { X86SSELevel = MMX; ToggleFeature(X86::FeatureMMX); }
if ((EDX >> 25) & 1) { X86SSELevel = SSE1; ToggleFeature(X86::FeatureSSE1); }
if ((EDX >> 26) & 1) { X86SSELevel = SSE2; ToggleFeature(X86::FeatureSSE2); }
if (ECX & 0x1) { X86SSELevel = SSE3; ToggleFeature(X86::FeatureSSE3); }
if ((ECX >> 9) & 1) { X86SSELevel = SSSE3; ToggleFeature(X86::FeatureSSSE3);}
if ((ECX >> 19) & 1) { X86SSELevel = SSE41; ToggleFeature(X86::FeatureSSE41);}
if ((ECX >> 20) & 1) { X86SSELevel = SSE42; ToggleFeature(X86::FeatureSSE42);}
// FIXME: AVX codegen support is not ready.
//if ((ECX >> 28) & 1) { HasAVX = true; ToggleFeature(X86::FeatureAVX); }
bool IsIntel = memcmp(text.c, "GenuineIntel", 12) == 0;
bool IsAMD = !IsIntel && memcmp(text.c, "AuthenticAMD", 12) == 0;
if (IsIntel && ((ECX >> 1) & 0x1)) {
HasCLMUL = true;
ToggleFeature(X86::FeatureCLMUL);
}
if (IsIntel && ((ECX >> 12) & 0x1)) {
HasFMA3 = true;
ToggleFeature(X86::FeatureFMA3);
}
if (IsIntel && ((ECX >> 22) & 0x1)) {
HasMOVBE = true;
ToggleFeature(X86::FeatureMOVBE);
}
if (IsIntel && ((ECX >> 23) & 0x1)) {
HasPOPCNT = true;
ToggleFeature(X86::FeaturePOPCNT);
}
if (IsIntel && ((ECX >> 25) & 0x1)) {
HasAES = true;
ToggleFeature(X86::FeatureAES);
}
if (IsIntel && ((ECX >> 29) & 0x1)) {
HasF16C = true;
ToggleFeature(X86::FeatureF16C);
}
if (IsIntel && ((ECX >> 30) & 0x1)) {
HasRDRAND = true;
ToggleFeature(X86::FeatureRDRAND);
}
if ((ECX >> 13) & 0x1) {
HasCmpxchg16b = true;
ToggleFeature(X86::FeatureCMPXCHG16B);
}
if (IsIntel || IsAMD) {
// Determine if bit test memory instructions are slow.
unsigned Family = 0;
unsigned Model = 0;
X86_MC::DetectFamilyModel(EAX, Family, Model);
if (IsAMD || (Family == 6 && Model >= 13)) {
IsBTMemSlow = true;
ToggleFeature(X86::FeatureSlowBTMem);
}
// If it's Nehalem, unaligned memory access is fast.
// FIXME: Nehalem is family 6. Also include Westmere and later processors?
if (Family == 15 && Model == 26) {
IsUAMemFast = true;
ToggleFeature(X86::FeatureFastUAMem);
}
unsigned MaxExtLevel;
X86_MC::GetCpuIDAndInfo(0x80000000, &MaxExtLevel, &EBX, &ECX, &EDX);
if (MaxExtLevel >= 0x80000001) {
X86_MC::GetCpuIDAndInfo(0x80000001, &EAX, &EBX, &ECX, &EDX);
if ((EDX >> 29) & 0x1) {
HasX86_64 = true;
ToggleFeature(X86::Feature64Bit);
}
if ((ECX >> 5) & 0x1) {
HasLZCNT = true;
ToggleFeature(X86::FeatureLZCNT);
}
if (IsAMD && ((ECX >> 6) & 0x1)) {
HasSSE4A = true;
ToggleFeature(X86::FeatureSSE4A);
}
if (IsAMD && ((ECX >> 16) & 0x1)) {
HasFMA4 = true;
ToggleFeature(X86::FeatureFMA4);
}
}
}
if (IsIntel && MaxLevel >= 7) {
if (!X86_MC::GetCpuIDAndInfoEx(0x7, 0x0, &EAX, &EBX, &ECX, &EDX)) {
if (EBX & 0x1) {
HasFSGSBase = true;
ToggleFeature(X86::FeatureFSGSBase);
}
if ((EBX >> 3) & 0x1) {
HasBMI = true;
ToggleFeature(X86::FeatureBMI);
}
// FIXME: AVX2 codegen support is not ready.
//if ((EBX >> 5) & 0x1) {
// HasAVX2 = true;
// ToggleFeature(X86::FeatureAVX2);
//}
if ((EBX >> 8) & 0x1) {
HasBMI2 = true;
ToggleFeature(X86::FeatureBMI2);
}
}
}
}
X86Subtarget::X86Subtarget(const std::string &TT, const std::string &CPU,
const std::string &FS,
unsigned StackAlignOverride, bool is64Bit)
: X86GenSubtargetInfo(TT, CPU, FS)
, PICStyle(PICStyles::None)
, X86SSELevel(NoMMXSSE)
, X863DNowLevel(NoThreeDNow)
, HasCMov(false)
, HasX86_64(false)
, HasPOPCNT(false)
, HasSSE4A(false)
, HasAVX(false)
, HasAVX2(false)
, HasAES(false)
, HasCLMUL(false)
, HasFMA3(false)
, HasFMA4(false)
, HasMOVBE(false)
, HasRDRAND(false)
, HasF16C(false)
, HasFSGSBase(false)
, HasLZCNT(false)
, HasBMI(false)
, HasBMI2(false)
, IsBTMemSlow(false)
, IsUAMemFast(false)
, HasVectorUAMem(false)
, HasCmpxchg16b(false)
, stackAlignment(8)
// FIXME: this is a known good value for Yonah. How about others?
, MaxInlineSizeThreshold(128)
, TargetTriple(TT)
, In64BitMode(is64Bit) {
// Determine default and user specified characteristics
if (!FS.empty() || !CPU.empty()) {
std::string CPUName = CPU;
if (CPUName.empty()) {
#if defined (__x86_64__) || defined(__i386__)
CPUName = sys::getHostCPUName();
#else
CPUName = "generic";
#endif
}
// 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);
} else {
// Otherwise, use CPUID to auto-detect feature set.
AutoDetectSubtargetFeatures();
// Make sure 64-bit features are available in 64-bit mode.
if (In64BitMode) {
HasX86_64 = true; ToggleFeature(X86::Feature64Bit);
HasCMov = true; ToggleFeature(X86::FeatureCMOV);
if (!HasAVX && X86SSELevel < SSE2) {
X86SSELevel = SSE2;
ToggleFeature(X86::FeatureSSE1);
ToggleFeature(X86::FeatureSSE2);
}
}
}
// 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);
if (HasAVX)
X86SSELevel = NoMMXSSE;
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!");
if(EnableSegmentedStacks && !isTargetELF())
report_fatal_error("Segmented stacks are only implemented on ELF.");
// Stack alignment is 16 bytes on Darwin, FreeBSD, Linux and Solaris (both
// 32 and 64 bit) and for all 64-bit targets.
if (StackAlignOverride)
stackAlignment = StackAlignOverride;
else if (isTargetDarwin() || isTargetFreeBSD() || isTargetLinux() ||
isTargetSolaris() || In64BitMode)
stackAlignment = 16;
}
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