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Use the MSVC __cpuid intrinsic instead of inline asm

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This works around PR16830 in LLVM when self-hosting clang on Windows.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188397 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Reid Kleckner 2013-08-14 18:21:51 +00:00
parent 1c6d387dc9
commit c97db8dfdd
1 changed files with 14 additions and 31 deletions
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45
lib/Support/Host.cpp
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@ -52,10 +52,19 @@ using namespace llvm;
/// GetX86CpuIDAndInfo - 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 bool GetX86CpuIDAndInfo(unsigned value, unsigned *rEAX,
unsigned *rEBX, unsigned *rECX, unsigned *rEDX) {
#if defined(__x86_64__) || defined(_M_AMD64) || defined (_M_X64)
#if defined(__GNUC__)
static bool GetX86CpuIDAndInfo(unsigned value, unsigned *rEAX, unsigned *rEBX,
unsigned *rECX, unsigned *rEDX) {
#if defined(_MSC_VER)
// The MSVC intrinsic is portable across x86 and x64.
int registers[4];
__cpuid(registers, value);
*rEAX = registers[0];
*rEBX = registers[1];
*rECX = registers[2];
*rEDX = registers[3];
return false;
#elif defined(__GNUC__)
#if defined(__x86_64__) || defined(_M_AMD64) || defined (_M_X64)
// gcc doesn't know cpuid would clobber ebx/rbx. Preseve it manually.
asm ("movq\t%%rbx, %%rsi\n\t"
"cpuid\n\t"
@ -66,19 +75,7 @@ static bool GetX86CpuIDAndInfo(unsigned value, unsigned *rEAX,
"=d" (*rEDX)
: "a" (value));
return false;
#elif defined(_MSC_VER)
int registers[4];
__cpuid(registers, value);
*rEAX = registers[0];
*rEBX = registers[1];
*rECX = registers[2];
*rEDX = registers[3];
return false;
#else
return true;
#endif
#elif defined(i386) || defined(__i386__) || defined(__x86__) || defined(_M_IX86)
#if defined(__GNUC__)
#elif defined(i386) || defined(__i386__) || defined(__x86__) || defined(_M_IX86)
asm ("movl\t%%ebx, %%esi\n\t"
"cpuid\n\t"
"xchgl\t%%ebx, %%esi\n\t"
@ -88,20 +85,6 @@ static bool GetX86CpuIDAndInfo(unsigned value, unsigned *rEAX,
"=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;
// pedantic #else returns to appease -Wunreachable-code (so we don't generate
// postprocessed code that looks like "return true; return false;")
#else