1 //===-- X86Subtarget.cpp - X86 Subtarget Information ------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the X86 specific subclass of TargetSubtarget.
12 //===----------------------------------------------------------------------===//
14 #include "X86Subtarget.h"
15 #include "X86GenSubtarget.inc"
16 #include "llvm/Module.h"
17 #include "llvm/Support/CommandLine.h"
18 #include "llvm/Target/TargetMachine.h"
21 cl::opt<X86Subtarget::AsmWriterFlavorTy>
22 AsmWriterFlavor("x86-asm-syntax", cl::init(X86Subtarget::Unset),
23 cl::desc("Choose style of code to emit from X86 backend:"),
25 clEnumValN(X86Subtarget::ATT, "att", " Emit AT&T-style assembly"),
26 clEnumValN(X86Subtarget::Intel, "intel", " Emit Intel-style assembly"),
30 /// True if accessing the GV requires an extra load. For Windows, dllimported
31 /// symbols are indirect, loading the value at address GV rather then the
32 /// value of GV itself. This means that the GlobalAddress must be in the base
33 /// or index register of the address, not the GV offset field.
34 bool X86Subtarget::GVRequiresExtraLoad(const GlobalValue* GV,
35 const TargetMachine& TM,
36 bool isDirectCall) const
39 if (TM.getRelocationModel() != Reloc::Static) {
40 if (isTargetDarwin()) {
41 return (!isDirectCall &&
42 (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
43 (GV->isDeclaration() && !GV->hasNotBeenReadFromBitcode())));
44 } else if (isTargetELF()) {
45 // Extra load is needed for all non-statics.
46 return (!isDirectCall &&
47 (GV->isDeclaration() || !GV->hasInternalLinkage()));
48 } else if (isTargetCygMing() || isTargetWindows()) {
49 return (GV->hasDLLImportLinkage());
56 /// GetCpuIDAndInfo - Execute the specified cpuid and return the 4 values in the
57 /// specified arguments. If we can't run cpuid on the host, return true.
58 bool X86::GetCpuIDAndInfo(unsigned value, unsigned *rEAX, unsigned *rEBX,
59 unsigned *rECX, unsigned *rEDX) {
60 #if defined(__x86_64__)
61 // gcc doesn't know cpuid would clobber ebx/rbx. Preseve it manually.
62 asm ("movq\t%%rbx, %%rsi\n\t"
64 "xchgq\t%%rbx, %%rsi\n\t"
71 #elif defined(i386) || defined(__i386__) || defined(__x86__) || defined(_M_IX86)
73 asm ("movl\t%%ebx, %%esi\n\t"
75 "xchgl\t%%ebx, %%esi\n\t"
82 #elif defined(_MSC_VER)
87 mov dword ptr [esi],eax
89 mov dword ptr [esi],ebx
91 mov dword ptr [esi],ecx
93 mov dword ptr [esi],edx
101 void X86Subtarget::AutoDetectSubtargetFeatures() {
102 unsigned EAX = 0, EBX = 0, ECX = 0, EDX = 0;
108 if (X86::GetCpuIDAndInfo(0, &EAX, text.u+0, text.u+2, text.u+1))
111 X86::GetCpuIDAndInfo(0x1, &EAX, &EBX, &ECX, &EDX);
113 if ((EDX >> 23) & 0x1) X86SSELevel = MMX;
114 if ((EDX >> 25) & 0x1) X86SSELevel = SSE1;
115 if ((EDX >> 26) & 0x1) X86SSELevel = SSE2;
116 if (ECX & 0x1) X86SSELevel = SSE3;
117 if ((ECX >> 9) & 0x1) X86SSELevel = SSSE3;
118 if ((ECX >> 19) & 0x1) X86SSELevel = SSE41;
119 if ((ECX >> 20) & 0x1) X86SSELevel = SSE42;
121 if (memcmp(text.c, "GenuineIntel", 12) == 0 ||
122 memcmp(text.c, "AuthenticAMD", 12) == 0) {
123 X86::GetCpuIDAndInfo(0x80000001, &EAX, &EBX, &ECX, &EDX);
124 HasX86_64 = (EDX >> 29) & 0x1;
128 static const char *GetCurrentX86CPU() {
129 unsigned EAX = 0, EBX = 0, ECX = 0, EDX = 0;
130 if (X86::GetCpuIDAndInfo(0x1, &EAX, &EBX, &ECX, &EDX))
132 unsigned Family = (EAX >> 8) & 0xf; // Bits 8 - 11
133 unsigned Model = (EAX >> 4) & 0xf; // Bits 4 - 7
134 X86::GetCpuIDAndInfo(0x80000001, &EAX, &EBX, &ECX, &EDX);
135 bool Em64T = (EDX >> 29) & 0x1;
142 X86::GetCpuIDAndInfo(0, &EAX, text.u+0, text.u+2, text.u+1);
143 if (memcmp(text.c, "GenuineIntel", 12) == 0) {
151 case 4: return "pentium-mmx";
152 default: return "pentium";
156 case 1: return "pentiumpro";
159 case 6: return "pentium2";
163 case 11: return "pentium3";
165 case 13: return "pentium-m";
166 case 14: return "yonah";
167 case 15: return "core2";
168 default: return "i686";
174 return (Em64T) ? "nocona" : "prescott";
176 return (Em64T) ? "x86-64" : "pentium4";
183 } else if (memcmp(text.c, "AuthenticAMD", 12) == 0) {
184 // FIXME: this poorly matches the generated SubtargetFeatureKV table. There
185 // appears to be no way to generate the wide variety of AMD-specific targets
186 // from the information returned from CPUID.
194 case 8: return "k6-2";
196 case 13: return "k6-3";
197 default: return "pentium";
201 case 4: return "athlon-tbird";
204 case 8: return "athlon-mp";
205 case 10: return "athlon-xp";
206 default: return "athlon";
210 case 1: return "opteron";
211 case 5: return "athlon-fx"; // also opteron
212 default: return "athlon64";
222 X86Subtarget::X86Subtarget(const Module &M, const std::string &FS, bool is64Bit)
223 : AsmFlavor(AsmWriterFlavor)
224 , PICStyle(PICStyle::None)
225 , X86SSELevel(NoMMXSSE)
229 // FIXME: this is a known good value for Yonah. How about others?
230 , MaxInlineSizeThreshold(128)
232 , TargetType(isELF) { // Default to ELF unless otherwise specified.
234 // Determine default and user specified characteristics
236 // If feature string is not empty, parse features string.
237 std::string CPU = GetCurrentX86CPU();
238 ParseSubtargetFeatures(FS, CPU);
240 // Otherwise, use CPUID to auto-detect feature set.
241 AutoDetectSubtargetFeatures();
244 // If requesting codegen for X86-64, make sure that 64-bit and SSE2 features
245 // are enabled. These are available on all x86-64 CPUs.
248 if (X86SSELevel < SSE2)
252 // Set the boolean corresponding to the current target triple, or the default
253 // if one cannot be determined, to true.
254 const std::string& TT = M.getTargetTriple();
255 if (TT.length() > 5) {
257 if ((Pos = TT.find("-darwin")) != std::string::npos) {
258 TargetType = isDarwin;
260 // Compute the darwin version number.
261 if (isdigit(TT[Pos+7]))
262 DarwinVers = atoi(&TT[Pos+7]);
264 DarwinVers = 8; // Minimum supported darwin is Tiger.
265 } else if (TT.find("cygwin") != std::string::npos) {
266 TargetType = isCygwin;
267 } else if (TT.find("mingw") != std::string::npos) {
268 TargetType = isMingw;
269 } else if (TT.find("win32") != std::string::npos) {
270 TargetType = isWindows;
271 } else if (TT.find("windows") != std::string::npos) {
272 TargetType = isWindows;
274 } else if (TT.empty()) {
275 #if defined(__CYGWIN__)
276 TargetType = isCygwin;
277 #elif defined(__MINGW32__)
278 TargetType = isMingw;
279 #elif defined(__APPLE__)
280 TargetType = isDarwin;
281 #if __APPLE_CC__ > 5400
282 DarwinVers = 9; // GCC 5400+ is Leopard.
284 DarwinVers = 8; // Minimum supported darwin is Tiger.
287 #elif defined(_WIN32)
288 TargetType = isWindows;
292 // If the asm syntax hasn't been overridden on the command line, use whatever
294 if (AsmFlavor == X86Subtarget::Unset) {
295 AsmFlavor = (TargetType == isWindows)
296 ? X86Subtarget::Intel : X86Subtarget::ATT;
299 if (TargetType == isDarwin ||
300 TargetType == isCygwin ||
301 TargetType == isMingw ||
302 (TargetType == isELF && Is64Bit))