fix: wrong results for ARM: empty getCurrentTime() for ARM and other architectures

easy_profiler_core/current_time.h

@@ -40,6 +40,9 @@ along with this program.If not, see <http://www.gnu.org/licenses/>.
 #else
 #include <chrono>
 #include <time.h>
+#ifdef __ARM_ARCH
+#include <sys/time.h>
+#endif//__ARM_ARCH
 #endif
 
 static inline profiler::timestamp_t getCurrentTime()
@@ -50,23 +53,89 @@ static inline profiler::timestamp_t getCurrentTime()
     if (!QueryPerformanceCounter(&elapsedMicroseconds))
         return 0;
     return (profiler::timestamp_t)elapsedMicroseconds.QuadPart;
-#else
+#else// not _WIN32
 
 #if (defined(__GNUC__) || defined(__ICC))
 
+	// part of code from google/benchmark library (Licensed under the Apache License, Version 2.0)
+	// see https://github.com/google/benchmark/blob/master/src/cycleclock.h#L111
     #if defined(__i386__)
-        unsigned long long t;
-        __asm__ __volatile__("rdtsc" : "=A"(t));
-        return t;
-    #elif defined(__x86_64__)
-        unsigned int hi, lo;
-        __asm__ __volatile__("rdtsc" : "=a" (lo), "=d" (hi));
-        return ((uint64_t)hi << 32) | lo;
-    #endif
+	  int64_t ret;
+	  __asm__ volatile("rdtsc" : "=A"(ret));
+	  return ret;
+	#elif defined(__x86_64__) || defined(__amd64__)
+	  uint64_t low, high;
+	  __asm__ volatile("rdtsc" : "=a"(low), "=d"(high));
+	  return (high << 32) | low;
+	#elif defined(__powerpc__) || defined(__ppc__)
+	  // This returns a time-base, which is not always precisely a cycle-count.
+	  int64_t tbl, tbu0, tbu1;
+	  asm("mftbu %0" : "=r"(tbu0));
+	  asm("mftb  %0" : "=r"(tbl));
+	  asm("mftbu %0" : "=r"(tbu1));
+	  tbl &= -static_cast<int64>(tbu0 == tbu1);
+	  // high 32 bits in tbu1; low 32 bits in tbl  (tbu0 is garbage)
+	  return (tbu1 << 32) | tbl;
+	#elif defined(__sparc__)
+	  int64_t tick;
+	  asm(".byte 0x83, 0x41, 0x00, 0x00");
+	  asm("mov   %%g1, %0" : "=r"(tick));
+	  return tick;
+	#elif defined(__ia64__)
+	  int64_t itc;
+	  asm("mov %0 = ar.itc" : "=r"(itc));
+	  return itc;
+	#elif defined(COMPILER_MSVC) && defined(_M_IX86)
+	  // Older MSVC compilers (like 7.x) don't seem to support the
+	  // __rdtsc intrinsic properly, so I prefer to use _asm instead
+	  // when I know it will work.  Otherwise, I'll use __rdtsc and hope
+	  // the code is being compiled with a non-ancient compiler.
+	  _asm rdtsc
+	#elif defined(COMPILER_MSVC)
+	  return __rdtsc();
+	#elif defined(__aarch64__)
+	  // System timer of ARMv8 runs at a different frequency than the CPU's.
+	  // The frequency is fixed, typically in the range 1-50MHz.  It can be
+	  // read at CNTFRQ special register.  We assume the OS has set up
+	  // the virtual timer properly.
+	  int64_t virtual_timer_value;
+	  asm volatile("mrs %0, cntvct_el0" : "=r"(virtual_timer_value));
+	  return virtual_timer_value;
+	#elif defined(__ARM_ARCH)
+	#if (__ARM_ARCH >= 6)  // V6 is the earliest arch that has a standard cyclecount
+	  uint32_t pmccntr;
+	  uint32_t pmuseren;
+	  uint32_t pmcntenset;
+	  // Read the user mode perf monitor counter access permissions.
+	  asm volatile("mrc p15, 0, %0, c9, c14, 0" : "=r"(pmuseren));
+	  if (pmuseren & 1) {  // Allows reading perfmon counters for user mode code.
+		asm volatile("mrc p15, 0, %0, c9, c12, 1" : "=r"(pmcntenset));
+		if (pmcntenset & 0x80000000ul) {  // Is it counting?
+		  asm volatile("mrc p15, 0, %0, c9, c13, 0" : "=r"(pmccntr));
+		  // The counter is set up to count every 64th cycle
+		  return static_cast<int64_t>(pmccntr) * 64;  // Should optimize to << 6
+		}
+	  }
+	#endif
+	  struct timeval tv;
+	  gettimeofday(&tv, nullptr);
+	  return static_cast<int64_t>(tv.tv_sec) * 1000000 + tv.tv_usec;
+	#elif defined(__mips__)
+	  // mips apparently only allows rdtsc for superusers, so we fall
+	  // back to gettimeofday.  It's possible clock_gettime would be better.
+	  struct timeval tv;
+	  gettimeofday(&tv, nullptr);
+	  return static_cast<int64_t>(tv.tv_sec) * 1000000 + tv.tv_usec;
+	#else
+	  #warning You need to define fast getCurrentTime() for your OS and CPU
+	  return std::chrono::time_point_cast<std::chrono::nanoseconds>(std::chrono::system_clock::now()).time_since_epoch().count();
+      #define USE_STD_CHRONO
+	#endif
 
-#else
+#else // not _WIN32, __GNUC__, __ICC
+	#warning You need to define fast getCurrentTime() for your OS and CPU
     return std::chrono::time_point_cast<std::chrono::nanoseconds>(std::chrono::system_clock::now()).time_since_epoch().count();
-#define USE_STD_CHRONO
+    #define USE_STD_CHRONO
 #endif
 
 #endif