/*
- * Copyright 2015 Facebook, Inc.
+ * Copyright 2017 Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* limitations under the License.
*/
-#ifndef FOLLY_CPUID_H_
-#define FOLLY_CPUID_H_
+#pragma once
#include <cstdint>
#include <folly/Portability.h>
+#ifdef _MSC_VER
+#include <intrin.h>
+#endif
+
namespace folly {
/**
*/
class CpuId {
public:
- CpuId() {
+ // Always inline in order for this to be usable from a __ifunc__.
+ // In shared library mode, a __ifunc__ runs at relocation time, while the
+ // PLT hasn't been fully populated yet; thus, ifuncs cannot use symbols
+ // with potentially external linkage. (This issue is less likely in opt
+ // mode since inlining happens more likely, and it doesn't happen for
+ // statically linked binaries which don't depend on the PLT)
+ FOLLY_ALWAYS_INLINE CpuId() {
#ifdef _MSC_VER
int reg[4];
__cpuid(static_cast<int*>(reg), 0);
const int n = reg[0];
if (n >= 1) {
__cpuid(static_cast<int*>(reg), 1);
- f1c_ = reg[2];
- f1d_ = reg[3];
+ f1c_ = uint32_t(reg[2]);
+ f1d_ = uint32_t(reg[3]);
}
if (n >= 7) {
__cpuidex(static_cast<int*>(reg), 7, 0);
- f7b_ = reg[1];
- f7c_ = reg[2];
+ f7b_ = uint32_t(reg[1]);
+ f7c_ = uint32_t(reg[2]);
+ }
+#elif defined(__i386__) && defined(__PIC__) && !defined(__clang__) && \
+ defined(__GNUC__)
+ // The following block like the normal cpuid branch below, but gcc
+ // reserves ebx for use of its pic register so we must specially
+ // handle the save and restore to avoid clobbering the register
+ uint32_t n;
+ __asm__(
+ "pushl %%ebx\n\t"
+ "cpuid\n\t"
+ "popl %%ebx\n\t"
+ : "=a"(n)
+ : "a"(0)
+ : "ecx", "edx");
+ if (n >= 1) {
+ uint32_t f1a;
+ __asm__(
+ "pushl %%ebx\n\t"
+ "cpuid\n\t"
+ "popl %%ebx\n\t"
+ : "=a"(f1a), "=c"(f1c_), "=d"(f1d_)
+ : "a"(1)
+ :);
+ }
+ if (n >= 7) {
+ __asm__(
+ "pushl %%ebx\n\t"
+ "cpuid\n\t"
+ "movl %%ebx, %%eax\n\r"
+ "popl %%ebx"
+ : "=a"(f7b_), "=c"(f7c_)
+ : "a"(7), "c"(0)
+ : "edx");
}
#elif FOLLY_X64 || defined(__i386__)
uint32_t n;
- __asm__("cpuid" : "=a"(n) : "a"(0) : "ebx", "edx", "ecx");
+ __asm__("cpuid" : "=a"(n) : "a"(0) : "ebx", "ecx", "edx");
if (n >= 1) {
- __asm__("cpuid" : "=c"(f1c_), "=d"(f1d_) : "a"(1) : "ebx");
+ uint32_t f1a;
+ __asm__("cpuid" : "=a"(f1a), "=c"(f1c_), "=d"(f1d_) : "a"(1) : "ebx");
}
if (n >= 7) {
- __asm__("cpuid" : "=b"(f7b_), "=c"(f7c_) : "a"(7), "c"(0) : "edx");
+ uint32_t f7a;
+ __asm__("cpuid"
+ : "=a"(f7a), "=b"(f7b_), "=c"(f7c_)
+ : "a"(7), "c"(0)
+ : "edx");
}
#endif
}
-#define X(name, r, bit) bool name() const { return (r) & (1U << bit); }
+#define X(name, r, bit) \
+ FOLLY_ALWAYS_INLINE bool name() const { \
+ return ((r) & (1U << bit)) != 0; \
+ }
- // cpuid(1): Processor Info and Feature Bits.
+// cpuid(1): Processor Info and Feature Bits.
#define C(name, bit) X(name, f1c_, bit)
C(sse3, 0)
C(pclmuldq, 1)
};
} // namespace folly
-
-#endif /* FOLLY_CPUID_H_ */