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 #include "X86Subtarget.h"
15 #include "X86InstrInfo.h"
16 #include "X86TargetMachine.h"
17 #include "llvm/IR/Attributes.h"
18 #include "llvm/IR/Function.h"
19 #include "llvm/IR/GlobalValue.h"
20 #include "llvm/Support/CommandLine.h"
21 #include "llvm/Support/Debug.h"
22 #include "llvm/Support/ErrorHandling.h"
23 #include "llvm/Support/Host.h"
24 #include "llvm/Support/raw_ostream.h"
25 #include "llvm/Target/TargetMachine.h"
26 #include "llvm/Target/TargetOptions.h"
27
28 #if defined(_MSC_VER)
29 #include <intrin.h>
30 #endif
31
32 using namespace llvm;
33
34 #define DEBUG_TYPE "subtarget"
35
36 #define GET_SUBTARGETINFO_TARGET_DESC
37 #define GET_SUBTARGETINFO_CTOR
38 #include "X86GenSubtargetInfo.inc"
39
40 // Temporary option to control early if-conversion for x86 while adding machine
41 // models.
42 static cl::opt<bool>
43 X86EarlyIfConv("x86-early-ifcvt", cl::Hidden,
44 cl::desc("Enable early if-conversion on X86"));
45
46
47 /// ClassifyBlockAddressReference - Classify a blockaddress reference for the
48 /// current subtarget according to how we should reference it in a non-pcrel
49 /// context.
ClassifyBlockAddressReference() const50 unsigned char X86Subtarget::ClassifyBlockAddressReference() const {
51 if (isPICStyleGOT()) // 32-bit ELF targets.
52 return X86II::MO_GOTOFF;
53
54 if (isPICStyleStubPIC()) // Darwin/32 in PIC mode.
55 return X86II::MO_PIC_BASE_OFFSET;
56
57 // Direct static reference to label.
58 return X86II::MO_NO_FLAG;
59 }
60
61 /// ClassifyGlobalReference - Classify a global variable reference for the
62 /// current subtarget according to how we should reference it in a non-pcrel
63 /// context.
64 unsigned char X86Subtarget::
ClassifyGlobalReference(const GlobalValue * GV,const TargetMachine & TM) const65 ClassifyGlobalReference(const GlobalValue *GV, const TargetMachine &TM) const {
66 // DLLImport only exists on windows, it is implemented as a load from a
67 // DLLIMPORT stub.
68 if (GV->hasDLLImportStorageClass())
69 return X86II::MO_DLLIMPORT;
70
71 bool isDecl = GV->isDeclarationForLinker();
72
73 // X86-64 in PIC mode.
74 if (isPICStyleRIPRel()) {
75 // Large model never uses stubs.
76 if (TM.getCodeModel() == CodeModel::Large)
77 return X86II::MO_NO_FLAG;
78
79 if (isTargetDarwin()) {
80 // If symbol visibility is hidden, the extra load is not needed if
81 // target is x86-64 or the symbol is definitely defined in the current
82 // translation unit.
83 if (GV->hasDefaultVisibility() &&
84 (isDecl || GV->isWeakForLinker()))
85 return X86II::MO_GOTPCREL;
86 } else if (!isTargetWin64()) {
87 assert(isTargetELF() && "Unknown rip-relative target");
88
89 // Extra load is needed for all externally visible.
90 if (!GV->hasLocalLinkage() && GV->hasDefaultVisibility())
91 return X86II::MO_GOTPCREL;
92 }
93
94 return X86II::MO_NO_FLAG;
95 }
96
97 if (isPICStyleGOT()) { // 32-bit ELF targets.
98 // Extra load is needed for all externally visible.
99 if (GV->hasLocalLinkage() || GV->hasHiddenVisibility())
100 return X86II::MO_GOTOFF;
101 return X86II::MO_GOT;
102 }
103
104 if (isPICStyleStubPIC()) { // Darwin/32 in PIC mode.
105 // Determine whether we have a stub reference and/or whether the reference
106 // is relative to the PIC base or not.
107
108 // If this is a strong reference to a definition, it is definitely not
109 // through a stub.
110 if (!isDecl && !GV->isWeakForLinker())
111 return X86II::MO_PIC_BASE_OFFSET;
112
113 // Unless we have a symbol with hidden visibility, we have to go through a
114 // normal $non_lazy_ptr stub because this symbol might be resolved late.
115 if (!GV->hasHiddenVisibility()) // Non-hidden $non_lazy_ptr reference.
116 return X86II::MO_DARWIN_NONLAZY_PIC_BASE;
117
118 // If symbol visibility is hidden, we have a stub for common symbol
119 // references and external declarations.
120 if (isDecl || GV->hasCommonLinkage()) {
121 // Hidden $non_lazy_ptr reference.
122 return X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE;
123 }
124
125 // Otherwise, no stub.
126 return X86II::MO_PIC_BASE_OFFSET;
127 }
128
129 if (isPICStyleStubNoDynamic()) { // Darwin/32 in -mdynamic-no-pic mode.
130 // Determine whether we have a stub reference.
131
132 // If this is a strong reference to a definition, it is definitely not
133 // through a stub.
134 if (!isDecl && !GV->isWeakForLinker())
135 return X86II::MO_NO_FLAG;
136
137 // Unless we have a symbol with hidden visibility, we have to go through a
138 // normal $non_lazy_ptr stub because this symbol might be resolved late.
139 if (!GV->hasHiddenVisibility()) // Non-hidden $non_lazy_ptr reference.
140 return X86II::MO_DARWIN_NONLAZY;
141
142 // Otherwise, no stub.
143 return X86II::MO_NO_FLAG;
144 }
145
146 // Direct static reference to global.
147 return X86II::MO_NO_FLAG;
148 }
149
150
151 /// getBZeroEntry - This function returns the name of a function which has an
152 /// interface like the non-standard bzero function, if such a function exists on
153 /// the current subtarget and it is considered prefereable over memset with zero
154 /// passed as the second argument. Otherwise it returns null.
getBZeroEntry() const155 const char *X86Subtarget::getBZeroEntry() const {
156 // Darwin 10 has a __bzero entry point for this purpose.
157 if (getTargetTriple().isMacOSX() &&
158 !getTargetTriple().isMacOSXVersionLT(10, 6))
159 return "__bzero";
160
161 return nullptr;
162 }
163
hasSinCos() const164 bool X86Subtarget::hasSinCos() const {
165 return getTargetTriple().isMacOSX() &&
166 !getTargetTriple().isMacOSXVersionLT(10, 9) &&
167 is64Bit();
168 }
169
170 /// IsLegalToCallImmediateAddr - Return true if the subtarget allows calls
171 /// to immediate address.
IsLegalToCallImmediateAddr(const TargetMachine & TM) const172 bool X86Subtarget::IsLegalToCallImmediateAddr(const TargetMachine &TM) const {
173 // FIXME: I386 PE/COFF supports PC relative calls using IMAGE_REL_I386_REL32
174 // but WinCOFFObjectWriter::RecordRelocation cannot emit them. Once it does,
175 // the following check for Win32 should be removed.
176 if (In64BitMode || isTargetWin32())
177 return false;
178 return isTargetELF() || TM.getRelocationModel() == Reloc::Static;
179 }
180
initSubtargetFeatures(StringRef CPU,StringRef FS)181 void X86Subtarget::initSubtargetFeatures(StringRef CPU, StringRef FS) {
182 std::string CPUName = CPU;
183 if (CPUName.empty())
184 CPUName = "generic";
185
186 // Make sure 64-bit features are available in 64-bit mode. (But make sure
187 // SSE2 can be turned off explicitly.)
188 std::string FullFS = FS;
189 if (In64BitMode) {
190 if (!FullFS.empty())
191 FullFS = "+64bit,+sse2," + FullFS;
192 else
193 FullFS = "+64bit,+sse2";
194 }
195
196 // If feature string is not empty, parse features string.
197 ParseSubtargetFeatures(CPUName, FullFS);
198
199 // Make sure the right MCSchedModel is used.
200 InitCPUSchedModel(CPUName);
201
202 InstrItins = getInstrItineraryForCPU(CPUName);
203
204 // It's important to keep the MCSubtargetInfo feature bits in sync with
205 // target data structure which is shared with MC code emitter, etc.
206 if (In64BitMode)
207 ToggleFeature(X86::Mode64Bit);
208 else if (In32BitMode)
209 ToggleFeature(X86::Mode32Bit);
210 else if (In16BitMode)
211 ToggleFeature(X86::Mode16Bit);
212 else
213 llvm_unreachable("Not 16-bit, 32-bit or 64-bit mode!");
214
215 DEBUG(dbgs() << "Subtarget features: SSELevel " << X86SSELevel
216 << ", 3DNowLevel " << X863DNowLevel
217 << ", 64bit " << HasX86_64 << "\n");
218 assert((!In64BitMode || HasX86_64) &&
219 "64-bit code requested on a subtarget that doesn't support it!");
220
221 // Stack alignment is 16 bytes on Darwin, Linux and Solaris (both
222 // 32 and 64 bit) and for all 64-bit targets.
223 if (StackAlignOverride)
224 stackAlignment = StackAlignOverride;
225 else if (isTargetDarwin() || isTargetLinux() || isTargetSolaris() ||
226 In64BitMode)
227 stackAlignment = 16;
228 }
229
initializeEnvironment()230 void X86Subtarget::initializeEnvironment() {
231 X86SSELevel = NoMMXSSE;
232 X863DNowLevel = NoThreeDNow;
233 HasCMov = false;
234 HasX86_64 = false;
235 HasPOPCNT = false;
236 HasSSE4A = false;
237 HasAES = false;
238 HasPCLMUL = false;
239 HasFMA = false;
240 HasFMA4 = false;
241 HasXOP = false;
242 HasTBM = false;
243 HasMOVBE = false;
244 HasRDRAND = false;
245 HasF16C = false;
246 HasFSGSBase = false;
247 HasLZCNT = false;
248 HasBMI = false;
249 HasBMI2 = false;
250 HasRTM = false;
251 HasHLE = false;
252 HasERI = false;
253 HasCDI = false;
254 HasPFI = false;
255 HasDQI = false;
256 HasBWI = false;
257 HasVLX = false;
258 HasADX = false;
259 HasSHA = false;
260 HasPRFCHW = false;
261 HasRDSEED = false;
262 IsBTMemSlow = false;
263 IsSHLDSlow = false;
264 IsUAMemFast = false;
265 IsUAMem32Slow = false;
266 HasSSEUnalignedMem = false;
267 HasCmpxchg16b = false;
268 UseLeaForSP = false;
269 HasSlowDivide32 = false;
270 HasSlowDivide64 = false;
271 PadShortFunctions = false;
272 CallRegIndirect = false;
273 LEAUsesAG = false;
274 SlowLEA = false;
275 SlowIncDec = false;
276 UseSqrtEst = false;
277 UseReciprocalEst = false;
278 stackAlignment = 4;
279 // FIXME: this is a known good value for Yonah. How about others?
280 MaxInlineSizeThreshold = 128;
281 }
282
initializeSubtargetDependencies(StringRef CPU,StringRef FS)283 X86Subtarget &X86Subtarget::initializeSubtargetDependencies(StringRef CPU,
284 StringRef FS) {
285 initializeEnvironment();
286 initSubtargetFeatures(CPU, FS);
287 return *this;
288 }
289
X86Subtarget(const std::string & TT,const std::string & CPU,const std::string & FS,const X86TargetMachine & TM,unsigned StackAlignOverride)290 X86Subtarget::X86Subtarget(const std::string &TT, const std::string &CPU,
291 const std::string &FS, const X86TargetMachine &TM,
292 unsigned StackAlignOverride)
293 : X86GenSubtargetInfo(TT, CPU, FS), X86ProcFamily(Others),
294 PICStyle(PICStyles::None), TargetTriple(TT),
295 StackAlignOverride(StackAlignOverride),
296 In64BitMode(TargetTriple.getArch() == Triple::x86_64),
297 In32BitMode(TargetTriple.getArch() == Triple::x86 &&
298 TargetTriple.getEnvironment() != Triple::CODE16),
299 In16BitMode(TargetTriple.getArch() == Triple::x86 &&
300 TargetTriple.getEnvironment() == Triple::CODE16),
301 TSInfo(*TM.getDataLayout()),
302 InstrInfo(initializeSubtargetDependencies(CPU, FS)), TLInfo(TM, *this),
303 FrameLowering(TargetFrameLowering::StackGrowsDown, getStackAlignment(),
304 is64Bit() ? -8 : -4) {
305 // Determine the PICStyle based on the target selected.
306 if (TM.getRelocationModel() == Reloc::Static) {
307 // Unless we're in PIC or DynamicNoPIC mode, set the PIC style to None.
308 setPICStyle(PICStyles::None);
309 } else if (is64Bit()) {
310 // PIC in 64 bit mode is always rip-rel.
311 setPICStyle(PICStyles::RIPRel);
312 } else if (isTargetCOFF()) {
313 setPICStyle(PICStyles::None);
314 } else if (isTargetDarwin()) {
315 if (TM.getRelocationModel() == Reloc::PIC_)
316 setPICStyle(PICStyles::StubPIC);
317 else {
318 assert(TM.getRelocationModel() == Reloc::DynamicNoPIC);
319 setPICStyle(PICStyles::StubDynamicNoPIC);
320 }
321 } else if (isTargetELF()) {
322 setPICStyle(PICStyles::GOT);
323 }
324 }
325
enableEarlyIfConversion() const326 bool X86Subtarget::enableEarlyIfConversion() const {
327 return hasCMov() && X86EarlyIfConv;
328 }
329
330