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//===-- X86Subtarget.cpp - X86 Subtarget Information ------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Nate Begeman and is distributed under the
// University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the X86 specific subclass of TargetSubtarget.
//
//===----------------------------------------------------------------------===//
#include "X86Subtarget.h"
//#include "X86GenSubtarget.inc"
#include "llvm/Module.h"
#include "llvm/Support/CommandLine.h"
#include <iostream>
using namespace llvm;
cl::opt<X86Subtarget::AsmWriterFlavorTy>
AsmWriterFlavor("x86-asm-syntax", cl::init(X86Subtarget::unset),
cl::desc("Choose style of code to emit from X86 backend:"),
cl::values(
clEnumValN(X86Subtarget::att, "att", " Emit AT&T-style assembly"),
clEnumValN(X86Subtarget::intel, "intel", " Emit Intel-style assembly"),
clEnumValEnd));
/// GetCpuIDAndInfo - Execute the specified cpuid and return the 4 values in the
/// specified arguments. If we can't run cpuid on the host, return true.
static inline bool GetCpuIDAndInfo(unsigned value, unsigned *rEAX, unsigned *rEBX,
unsigned *rECX, unsigned *rEDX) {
#if defined(__x86_64__)
asm ("pushq\t%%rbx\n\t"
"cpuid\n\t"
"movl\t%%ebx, %%esi\n\t"
"popq\t%%rbx"
: "=a" (*rEAX),
"=S" (*rEBX),
"=c" (*rECX),
"=d" (*rEDX)
: "a" (value));
return false;
#elif defined(i386) || defined(__i386__) || defined(__x86__) || defined(_M_IX86)
#if defined(__GNUC__)
asm ("pushl\t%%ebx\n\t"
"cpuid\n\t"
"movl\t%%ebx, %%esi\n\t"
"popl\t%%ebx"
: "=a" (*rEAX),
"=S" (*rEBX),
"=c" (*rECX),
"=d" (*rEDX)
: "a" (value));
return false;
#elif defined(_MSC_VER)
__asm {
mov eax,value
cpuid
mov esi,rEAX
mov dword ptr [esi],eax
mov esi,rEBX
mov dword ptr [esi],ebx
mov esi,rECX
mov dword ptr [esi],ecx
mov esi,rEDX
mov dword ptr [esi],edx
}
return false;
#endif
#endif
return true;
}
void X86Subtarget::DetectSubtargetFeatures() {
unsigned EAX = 0, EBX = 0, ECX = 0, EDX = 0;
union {
unsigned u[3];
char c[12];
} text;
if (GetCpuIDAndInfo(0, &EAX, text.u+0, text.u+2, text.u+1))
return;
// FIXME: support for AMD family of processors.
if (memcmp(text.c, "GenuineIntel", 12) == 0) {
GetCpuIDAndInfo(0x1, &EAX, &EBX, &ECX, &EDX);
if ((EDX >> 23) & 0x1) X86SSELevel = MMX;
if ((EDX >> 25) & 0x1) X86SSELevel = SSE1;
if ((EDX >> 26) & 0x1) X86SSELevel = SSE2;
if (ECX & 0x1) X86SSELevel = SSE3;
GetCpuIDAndInfo(0x80000001, &EAX, &EBX, &ECX, &EDX);
HasX86_64 = (EDX >> 29) & 0x1;
}
}
X86Subtarget::X86Subtarget(const Module &M, const std::string &FS, bool is64Bit)
: AsmFlavor(AsmWriterFlavor)
, X86SSELevel(NoMMXSSE)
, HasX86_64(false)
, stackAlignment(8)
// FIXME: this is a known good value for Yonah. How about others?
, MinRepStrSizeThreshold(128)
, Is64Bit(is64Bit)
, TargetType(isELF) { // Default to ELF unless otherwise specified.
// Determine default and user specified characteristics
DetectSubtargetFeatures();
if (Is64Bit && !HasX86_64) {
std::cerr << "Warning: Generation of 64-bit code for a 32-bit processor "
"requested.\n";
HasX86_64 = true;
}
// Set the boolean corresponding to the current target triple, or the default
// if one cannot be determined, to true.
const std::string& TT = M.getTargetTriple();
if (TT.length() > 5) {
if (TT.find("cygwin") != std::string::npos ||
TT.find("mingw") != std::string::npos)
TargetType = isCygwin;
else if (TT.find("darwin") != std::string::npos)
TargetType = isDarwin;
else if (TT.find("win32") != std::string::npos)
TargetType = isWindows;
} else if (TT.empty()) {
#if defined(__CYGWIN__) || defined(__MINGW32__)
TargetType = isCygwin;
#elif defined(__APPLE__)
TargetType = isDarwin;
#elif defined(_WIN32)
TargetType = isWindows;
#endif
}
// If the asm syntax hasn't been overridden on the command line, use whatever
// the target wants.
if (AsmFlavor == X86Subtarget::unset) {
if (TargetType == isWindows) {
AsmFlavor = X86Subtarget::intel;
} else {
AsmFlavor = X86Subtarget::att;
}
}
if (TargetType == isDarwin || TargetType == isCygwin)
stackAlignment = 16;
}
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