1 //===-- X86Subtarget.cpp - X86 Subtarget Information ----------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements the X86 specific subclass of TargetSubtargetInfo.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #define DEBUG_TYPE "subtarget"
15 #include "X86Subtarget.h"
16 #include "X86InstrInfo.h"
17 #include "llvm/IR/Attributes.h"
18 #include "llvm/IR/Function.h"
19 #include "llvm/IR/GlobalValue.h"
20 #include "llvm/Support/Debug.h"
21 #include "llvm/Support/ErrorHandling.h"
22 #include "llvm/Support/Host.h"
23 #include "llvm/Support/raw_ostream.h"
24 #include "llvm/Target/TargetMachine.h"
25 #include "llvm/Target/TargetOptions.h"
26
27 #define GET_SUBTARGETINFO_TARGET_DESC
28 #define GET_SUBTARGETINFO_CTOR
29 #include "X86GenSubtargetInfo.inc"
30
31 using namespace llvm;
32
33 #if defined(_MSC_VER)
34 #include <intrin.h>
35 #endif
36
37 /// ClassifyBlockAddressReference - Classify a blockaddress reference for the
38 /// current subtarget according to how we should reference it in a non-pcrel
39 /// context.
ClassifyBlockAddressReference() const40 unsigned char X86Subtarget::ClassifyBlockAddressReference() const {
41 if (isPICStyleGOT()) // 32-bit ELF targets.
42 return X86II::MO_GOTOFF;
43
44 if (isPICStyleStubPIC()) // Darwin/32 in PIC mode.
45 return X86II::MO_PIC_BASE_OFFSET;
46
47 // Direct static reference to label.
48 return X86II::MO_NO_FLAG;
49 }
50
51 /// ClassifyGlobalReference - Classify a global variable reference for the
52 /// current subtarget according to how we should reference it in a non-pcrel
53 /// context.
54 unsigned char X86Subtarget::
ClassifyGlobalReference(const GlobalValue * GV,const TargetMachine & TM) const55 ClassifyGlobalReference(const GlobalValue *GV, const TargetMachine &TM) const {
56 // DLLImport only exists on windows, it is implemented as a load from a
57 // DLLIMPORT stub.
58 if (GV->hasDLLImportLinkage())
59 return X86II::MO_DLLIMPORT;
60
61 // Determine whether this is a reference to a definition or a declaration.
62 // Materializable GVs (in JIT lazy compilation mode) do not require an extra
63 // load from stub.
64 bool isDecl = GV->hasAvailableExternallyLinkage();
65 if (GV->isDeclaration() && !GV->isMaterializable())
66 isDecl = true;
67
68 // X86-64 in PIC mode.
69 if (isPICStyleRIPRel()) {
70 // Large model never uses stubs.
71 if (TM.getCodeModel() == CodeModel::Large)
72 return X86II::MO_NO_FLAG;
73
74 if (isTargetDarwin()) {
75 // If symbol visibility is hidden, the extra load is not needed if
76 // target is x86-64 or the symbol is definitely defined in the current
77 // translation unit.
78 if (GV->hasDefaultVisibility() &&
79 (isDecl || GV->isWeakForLinker()))
80 return X86II::MO_GOTPCREL;
81 } else if (!isTargetWin64()) {
82 assert(isTargetELF() && "Unknown rip-relative target");
83
84 // Extra load is needed for all externally visible.
85 if (!GV->hasLocalLinkage() && GV->hasDefaultVisibility())
86 return X86II::MO_GOTPCREL;
87 }
88
89 return X86II::MO_NO_FLAG;
90 }
91
92 if (isPICStyleGOT()) { // 32-bit ELF targets.
93 // Extra load is needed for all externally visible.
94 if (GV->hasLocalLinkage() || GV->hasHiddenVisibility())
95 return X86II::MO_GOTOFF;
96 return X86II::MO_GOT;
97 }
98
99 if (isPICStyleStubPIC()) { // Darwin/32 in PIC mode.
100 // Determine whether we have a stub reference and/or whether the reference
101 // is relative to the PIC base or not.
102
103 // If this is a strong reference to a definition, it is definitely not
104 // through a stub.
105 if (!isDecl && !GV->isWeakForLinker())
106 return X86II::MO_PIC_BASE_OFFSET;
107
108 // Unless we have a symbol with hidden visibility, we have to go through a
109 // normal $non_lazy_ptr stub because this symbol might be resolved late.
110 if (!GV->hasHiddenVisibility()) // Non-hidden $non_lazy_ptr reference.
111 return X86II::MO_DARWIN_NONLAZY_PIC_BASE;
112
113 // If symbol visibility is hidden, we have a stub for common symbol
114 // references and external declarations.
115 if (isDecl || GV->hasCommonLinkage()) {
116 // Hidden $non_lazy_ptr reference.
117 return X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE;
118 }
119
120 // Otherwise, no stub.
121 return X86II::MO_PIC_BASE_OFFSET;
122 }
123
124 if (isPICStyleStubNoDynamic()) { // Darwin/32 in -mdynamic-no-pic mode.
125 // Determine whether we have a stub reference.
126
127 // If this is a strong reference to a definition, it is definitely not
128 // through a stub.
129 if (!isDecl && !GV->isWeakForLinker())
130 return X86II::MO_NO_FLAG;
131
132 // Unless we have a symbol with hidden visibility, we have to go through a
133 // normal $non_lazy_ptr stub because this symbol might be resolved late.
134 if (!GV->hasHiddenVisibility()) // Non-hidden $non_lazy_ptr reference.
135 return X86II::MO_DARWIN_NONLAZY;
136
137 // Otherwise, no stub.
138 return X86II::MO_NO_FLAG;
139 }
140
141 // Direct static reference to global.
142 return X86II::MO_NO_FLAG;
143 }
144
145
146 /// getBZeroEntry - This function returns the name of a function which has an
147 /// interface like the non-standard bzero function, if such a function exists on
148 /// the current subtarget and it is considered prefereable over memset with zero
149 /// passed as the second argument. Otherwise it returns null.
getBZeroEntry() const150 const char *X86Subtarget::getBZeroEntry() const {
151 // Darwin 10 has a __bzero entry point for this purpose.
152 if (getTargetTriple().isMacOSX() &&
153 !getTargetTriple().isMacOSXVersionLT(10, 6))
154 return "__bzero";
155
156 return 0;
157 }
158
hasSinCos() const159 bool X86Subtarget::hasSinCos() const {
160 return getTargetTriple().isMacOSX() &&
161 !getTargetTriple().isMacOSXVersionLT(10, 9) &&
162 is64Bit();
163 }
164
165 /// IsLegalToCallImmediateAddr - Return true if the subtarget allows calls
166 /// to immediate address.
IsLegalToCallImmediateAddr(const TargetMachine & TM) const167 bool X86Subtarget::IsLegalToCallImmediateAddr(const TargetMachine &TM) const {
168 if (In64BitMode)
169 return false;
170 return isTargetELF() || TM.getRelocationModel() == Reloc::Static;
171 }
172
OSHasAVXSupport()173 static bool OSHasAVXSupport() {
174 #if defined(i386) || defined(__i386__) || defined(__x86__) || defined(_M_IX86)\
175 || defined(__x86_64__) || defined(_M_AMD64) || defined (_M_X64)
176 #if defined(__GNUC__)
177 // Check xgetbv; this uses a .byte sequence instead of the instruction
178 // directly because older assemblers do not include support for xgetbv and
179 // there is no easy way to conditionally compile based on the assembler used.
180 int rEAX, rEDX;
181 __asm__ (".byte 0x0f, 0x01, 0xd0" : "=a" (rEAX), "=d" (rEDX) : "c" (0));
182 #elif defined(_MSC_FULL_VER) && defined(_XCR_XFEATURE_ENABLED_MASK)
183 unsigned long long rEAX = _xgetbv(_XCR_XFEATURE_ENABLED_MASK);
184 #else
185 int rEAX = 0; // Ensures we return false
186 #endif
187 return (rEAX & 6) == 6;
188 #else
189 return false;
190 #endif
191 }
192
AutoDetectSubtargetFeatures()193 void X86Subtarget::AutoDetectSubtargetFeatures() {
194 unsigned EAX = 0, EBX = 0, ECX = 0, EDX = 0;
195 unsigned MaxLevel;
196 union {
197 unsigned u[3];
198 char c[12];
199 } text;
200
201 if (X86_MC::GetCpuIDAndInfo(0, &MaxLevel, text.u+0, text.u+2, text.u+1) ||
202 MaxLevel < 1)
203 return;
204
205 X86_MC::GetCpuIDAndInfo(0x1, &EAX, &EBX, &ECX, &EDX);
206
207 if ((EDX >> 15) & 1) { HasCMov = true; ToggleFeature(X86::FeatureCMOV); }
208 if ((EDX >> 23) & 1) { X86SSELevel = MMX; ToggleFeature(X86::FeatureMMX); }
209 if ((EDX >> 25) & 1) { X86SSELevel = SSE1; ToggleFeature(X86::FeatureSSE1); }
210 if ((EDX >> 26) & 1) { X86SSELevel = SSE2; ToggleFeature(X86::FeatureSSE2); }
211 if (ECX & 0x1) { X86SSELevel = SSE3; ToggleFeature(X86::FeatureSSE3); }
212 if ((ECX >> 9) & 1) { X86SSELevel = SSSE3; ToggleFeature(X86::FeatureSSSE3);}
213 if ((ECX >> 19) & 1) { X86SSELevel = SSE41; ToggleFeature(X86::FeatureSSE41);}
214 if ((ECX >> 20) & 1) { X86SSELevel = SSE42; ToggleFeature(X86::FeatureSSE42);}
215 if (((ECX >> 27) & 1) && ((ECX >> 28) & 1) && OSHasAVXSupport()) {
216 X86SSELevel = AVX; ToggleFeature(X86::FeatureAVX);
217 }
218
219 bool IsIntel = memcmp(text.c, "GenuineIntel", 12) == 0;
220 bool IsAMD = !IsIntel && memcmp(text.c, "AuthenticAMD", 12) == 0;
221
222 if ((ECX >> 1) & 0x1) {
223 HasPCLMUL = true;
224 ToggleFeature(X86::FeaturePCLMUL);
225 }
226 if ((ECX >> 12) & 0x1) {
227 HasFMA = true;
228 ToggleFeature(X86::FeatureFMA);
229 }
230 if (IsIntel && ((ECX >> 22) & 0x1)) {
231 HasMOVBE = true;
232 ToggleFeature(X86::FeatureMOVBE);
233 }
234 if ((ECX >> 23) & 0x1) {
235 HasPOPCNT = true;
236 ToggleFeature(X86::FeaturePOPCNT);
237 }
238 if ((ECX >> 25) & 0x1) {
239 HasAES = true;
240 ToggleFeature(X86::FeatureAES);
241 }
242 if ((ECX >> 29) & 0x1) {
243 HasF16C = true;
244 ToggleFeature(X86::FeatureF16C);
245 }
246 if (IsIntel && ((ECX >> 30) & 0x1)) {
247 HasRDRAND = true;
248 ToggleFeature(X86::FeatureRDRAND);
249 }
250
251 if ((ECX >> 13) & 0x1) {
252 HasCmpxchg16b = true;
253 ToggleFeature(X86::FeatureCMPXCHG16B);
254 }
255
256 if (IsIntel || IsAMD) {
257 // Determine if bit test memory instructions are slow.
258 unsigned Family = 0;
259 unsigned Model = 0;
260 X86_MC::DetectFamilyModel(EAX, Family, Model);
261 if (IsAMD || (Family == 6 && Model >= 13)) {
262 IsBTMemSlow = true;
263 ToggleFeature(X86::FeatureSlowBTMem);
264 }
265
266 // If it's an Intel chip since Nehalem and not an Atom chip, unaligned
267 // memory access is fast. We hard code model numbers here because they
268 // aren't strictly increasing for Intel chips it seems.
269 if (IsIntel &&
270 ((Family == 6 && Model == 0x1E) || // Nehalem: Clarksfield, Lynnfield,
271 // Jasper Froest
272 (Family == 6 && Model == 0x1A) || // Nehalem: Bloomfield, Nehalem-EP
273 (Family == 6 && Model == 0x2E) || // Nehalem: Nehalem-EX
274 (Family == 6 && Model == 0x25) || // Westmere: Arrandale, Clarksdale
275 (Family == 6 && Model == 0x2C) || // Westmere: Gulftown, Westmere-EP
276 (Family == 6 && Model == 0x2F) || // Westmere: Westmere-EX
277 (Family == 6 && Model == 0x2A) || // SandyBridge
278 (Family == 6 && Model == 0x2D) || // SandyBridge: SandyBridge-E*
279 (Family == 6 && Model == 0x3A))) {// IvyBridge
280 IsUAMemFast = true;
281 ToggleFeature(X86::FeatureFastUAMem);
282 }
283
284 // Set processor type. Currently only Atom is detected.
285 if (Family == 6 &&
286 (Model == 28 || Model == 38 || Model == 39
287 || Model == 53 || Model == 54)) {
288 X86ProcFamily = IntelAtom;
289
290 UseLeaForSP = true;
291 ToggleFeature(X86::FeatureLeaForSP);
292 }
293
294 unsigned MaxExtLevel;
295 X86_MC::GetCpuIDAndInfo(0x80000000, &MaxExtLevel, &EBX, &ECX, &EDX);
296
297 if (MaxExtLevel >= 0x80000001) {
298 X86_MC::GetCpuIDAndInfo(0x80000001, &EAX, &EBX, &ECX, &EDX);
299 if ((EDX >> 29) & 0x1) {
300 HasX86_64 = true;
301 ToggleFeature(X86::Feature64Bit);
302 }
303 if ((ECX >> 5) & 0x1) {
304 HasLZCNT = true;
305 ToggleFeature(X86::FeatureLZCNT);
306 }
307 if (IsIntel && ((ECX >> 8) & 0x1)) {
308 HasPRFCHW = true;
309 ToggleFeature(X86::FeaturePRFCHW);
310 }
311 if (IsAMD) {
312 if ((ECX >> 6) & 0x1) {
313 HasSSE4A = true;
314 ToggleFeature(X86::FeatureSSE4A);
315 }
316 if ((ECX >> 11) & 0x1) {
317 HasXOP = true;
318 ToggleFeature(X86::FeatureXOP);
319 }
320 if ((ECX >> 16) & 0x1) {
321 HasFMA4 = true;
322 ToggleFeature(X86::FeatureFMA4);
323 }
324 }
325 }
326 }
327
328 if (MaxLevel >= 7) {
329 if (!X86_MC::GetCpuIDAndInfoEx(0x7, 0x0, &EAX, &EBX, &ECX, &EDX)) {
330 if (IsIntel && (EBX & 0x1)) {
331 HasFSGSBase = true;
332 ToggleFeature(X86::FeatureFSGSBase);
333 }
334 if ((EBX >> 3) & 0x1) {
335 HasBMI = true;
336 ToggleFeature(X86::FeatureBMI);
337 }
338 if ((EBX >> 4) & 0x1) {
339 HasHLE = true;
340 ToggleFeature(X86::FeatureHLE);
341 }
342 if (IsIntel && ((EBX >> 5) & 0x1)) {
343 X86SSELevel = AVX2;
344 ToggleFeature(X86::FeatureAVX2);
345 }
346 if (IsIntel && ((EBX >> 8) & 0x1)) {
347 HasBMI2 = true;
348 ToggleFeature(X86::FeatureBMI2);
349 }
350 if (IsIntel && ((EBX >> 11) & 0x1)) {
351 HasRTM = true;
352 ToggleFeature(X86::FeatureRTM);
353 }
354 if (IsIntel && ((EBX >> 19) & 0x1)) {
355 HasADX = true;
356 ToggleFeature(X86::FeatureADX);
357 }
358 if (IsIntel && ((EBX >> 18) & 0x1)) {
359 HasRDSEED = true;
360 ToggleFeature(X86::FeatureRDSEED);
361 }
362 }
363 }
364 }
365
resetSubtargetFeatures(const MachineFunction * MF)366 void X86Subtarget::resetSubtargetFeatures(const MachineFunction *MF) {
367 AttributeSet FnAttrs = MF->getFunction()->getAttributes();
368 Attribute CPUAttr = FnAttrs.getAttribute(AttributeSet::FunctionIndex,
369 "target-cpu");
370 Attribute FSAttr = FnAttrs.getAttribute(AttributeSet::FunctionIndex,
371 "target-features");
372 std::string CPU =
373 !CPUAttr.hasAttribute(Attribute::None) ?CPUAttr.getValueAsString() : "";
374 std::string FS =
375 !FSAttr.hasAttribute(Attribute::None) ? FSAttr.getValueAsString() : "";
376 if (!FS.empty()) {
377 initializeEnvironment();
378 resetSubtargetFeatures(CPU, FS);
379 }
380 }
381
resetSubtargetFeatures(StringRef CPU,StringRef FS)382 void X86Subtarget::resetSubtargetFeatures(StringRef CPU, StringRef FS) {
383 std::string CPUName = CPU;
384 if (!FS.empty() || !CPU.empty()) {
385 if (CPUName.empty()) {
386 #if defined(i386) || defined(__i386__) || defined(__x86__) || defined(_M_IX86)\
387 || defined(__x86_64__) || defined(_M_AMD64) || defined (_M_X64)
388 CPUName = sys::getHostCPUName();
389 #else
390 CPUName = "generic";
391 #endif
392 }
393
394 // Make sure 64-bit features are available in 64-bit mode. (But make sure
395 // SSE2 can be turned off explicitly.)
396 std::string FullFS = FS;
397 if (In64BitMode) {
398 if (!FullFS.empty())
399 FullFS = "+64bit,+sse2," + FullFS;
400 else
401 FullFS = "+64bit,+sse2";
402 }
403
404 // If feature string is not empty, parse features string.
405 ParseSubtargetFeatures(CPUName, FullFS);
406 } else {
407 if (CPUName.empty()) {
408 #if defined (__x86_64__) || defined(__i386__)
409 CPUName = sys::getHostCPUName();
410 #else
411 CPUName = "generic";
412 #endif
413 }
414 // Otherwise, use CPUID to auto-detect feature set.
415 AutoDetectSubtargetFeatures();
416
417 // Make sure 64-bit features are available in 64-bit mode.
418 if (In64BitMode) {
419 HasX86_64 = true; ToggleFeature(X86::Feature64Bit);
420 HasCMov = true; ToggleFeature(X86::FeatureCMOV);
421
422 if (X86SSELevel < SSE2) {
423 X86SSELevel = SSE2;
424 ToggleFeature(X86::FeatureSSE1);
425 ToggleFeature(X86::FeatureSSE2);
426 }
427 }
428 }
429
430 // CPUName may have been set by the CPU detection code. Make sure the
431 // new MCSchedModel is used.
432 InitMCProcessorInfo(CPUName, FS);
433
434 if (X86ProcFamily == IntelAtom)
435 PostRAScheduler = true;
436
437 InstrItins = getInstrItineraryForCPU(CPUName);
438
439 // It's important to keep the MCSubtargetInfo feature bits in sync with
440 // target data structure which is shared with MC code emitter, etc.
441 if (In64BitMode)
442 ToggleFeature(X86::Mode64Bit);
443
444 DEBUG(dbgs() << "Subtarget features: SSELevel " << X86SSELevel
445 << ", 3DNowLevel " << X863DNowLevel
446 << ", 64bit " << HasX86_64 << "\n");
447 assert((!In64BitMode || HasX86_64) &&
448 "64-bit code requested on a subtarget that doesn't support it!");
449
450 // Stack alignment is 16 bytes on Darwin, Linux and Solaris (both
451 // 32 and 64 bit) and for all 64-bit targets.
452 if (StackAlignOverride)
453 stackAlignment = StackAlignOverride;
454 else if (isTargetDarwin() || isTargetLinux() || isTargetSolaris() ||
455 In64BitMode)
456 stackAlignment = 16;
457 }
458
initializeEnvironment()459 void X86Subtarget::initializeEnvironment() {
460 X86SSELevel = NoMMXSSE;
461 X863DNowLevel = NoThreeDNow;
462 HasCMov = false;
463 HasX86_64 = false;
464 HasPOPCNT = false;
465 HasSSE4A = false;
466 HasAES = false;
467 HasPCLMUL = false;
468 HasFMA = false;
469 HasFMA4 = false;
470 HasXOP = false;
471 HasMOVBE = false;
472 HasRDRAND = false;
473 HasF16C = false;
474 HasFSGSBase = false;
475 HasLZCNT = false;
476 HasBMI = false;
477 HasBMI2 = false;
478 HasRTM = false;
479 HasHLE = false;
480 HasERI = false;
481 HasCDI = false;
482 HasPFI=false;
483 HasADX = false;
484 HasPRFCHW = false;
485 HasRDSEED = false;
486 IsBTMemSlow = false;
487 IsUAMemFast = false;
488 HasVectorUAMem = false;
489 HasCmpxchg16b = false;
490 UseLeaForSP = false;
491 HasSlowDivide = false;
492 PostRAScheduler = false;
493 PadShortFunctions = false;
494 CallRegIndirect = false;
495 LEAUsesAG = false;
496 stackAlignment = 4;
497 // FIXME: this is a known good value for Yonah. How about others?
498 MaxInlineSizeThreshold = 128;
499 }
500
X86Subtarget(const std::string & TT,const std::string & CPU,const std::string & FS,unsigned StackAlignOverride,bool is64Bit)501 X86Subtarget::X86Subtarget(const std::string &TT, const std::string &CPU,
502 const std::string &FS,
503 unsigned StackAlignOverride, bool is64Bit)
504 : X86GenSubtargetInfo(TT, CPU, FS)
505 , X86ProcFamily(Others)
506 , PICStyle(PICStyles::None)
507 , TargetTriple(TT)
508 , StackAlignOverride(StackAlignOverride)
509 , In64BitMode(is64Bit) {
510 initializeEnvironment();
511 resetSubtargetFeatures(CPU, FS);
512 }
513
enablePostRAScheduler(CodeGenOpt::Level OptLevel,TargetSubtargetInfo::AntiDepBreakMode & Mode,RegClassVector & CriticalPathRCs) const514 bool X86Subtarget::enablePostRAScheduler(
515 CodeGenOpt::Level OptLevel,
516 TargetSubtargetInfo::AntiDepBreakMode& Mode,
517 RegClassVector& CriticalPathRCs) const {
518 Mode = TargetSubtargetInfo::ANTIDEP_CRITICAL;
519 CriticalPathRCs.clear();
520 return PostRAScheduler && OptLevel >= CodeGenOpt::Default;
521 }
522