gcc/libgo/runtime/runtime.c

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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#include <signal.h>
#include <unistd.h>
#include "config.h"
#include "runtime.h"
#include "array.h"
#include "go-panic.h"
// The GOTRACEBACK environment variable controls the
// behavior of a Go program that is crashing and exiting.
// GOTRACEBACK=0 suppress all tracebacks
// GOTRACEBACK=1 default behavior - show tracebacks but exclude runtime frames
// GOTRACEBACK=2 show tracebacks including runtime frames
// GOTRACEBACK=crash show tracebacks including runtime frames, then crash (core dump etc)
int32
runtime_gotraceback(bool *crash)
{
const byte *p;
if(crash != nil)
*crash = false;
p = runtime_getenv("GOTRACEBACK");
if(p == nil || p[0] == '\0')
return 1; // default is on
if(runtime_strcmp((const char *)p, "crash") == 0) {
if(crash != nil)
*crash = true;
return 2; // extra information
}
return runtime_atoi(p);
}
static int32 argc;
static byte** argv;
extern Slice os_Args __asm__ (GOSYM_PREFIX "os.Args");
extern Slice syscall_Envs __asm__ (GOSYM_PREFIX "syscall.Envs");
void (*runtime_sysargs)(int32, uint8**);
void
runtime_args(int32 c, byte **v)
{
argc = c;
argv = v;
if(runtime_sysargs != nil)
runtime_sysargs(c, v);
}
byte*
runtime_progname()
{
return argc == 0 ? nil : argv[0];
}
// Information about what cpu features are available.
// Set on startup in asm_{x86/amd64}.s.
uint32 runtime_cpuid_ecx;
uint32 runtime_cpuid_edx;
void
runtime_goargs(void)
{
String *s;
int32 i;
// for windows implementation see "os" package
if(Windows)
return;
s = runtime_malloc(argc*sizeof s[0]);
for(i=0; i<argc; i++)
s[i] = runtime_gostringnocopy((const byte*)argv[i]);
os_Args.__values = (void*)s;
os_Args.__count = argc;
os_Args.__capacity = argc;
}
void
runtime_goenvs_unix(void)
{
String *s;
int32 i, n;
for(n=0; argv[argc+1+n] != 0; n++)
;
s = runtime_malloc(n*sizeof s[0]);
for(i=0; i<n; i++)
s[i] = runtime_gostringnocopy(argv[argc+1+i]);
syscall_Envs.__values = (void*)s;
syscall_Envs.__count = n;
syscall_Envs.__capacity = n;
}
int32
runtime_atoi(const byte *p)
{
int32 n;
n = 0;
while('0' <= *p && *p <= '9')
n = n*10 + *p++ - '0';
return n;
}
static struct root_list runtime_roots =
{ nil,
{ { &syscall_Envs, sizeof syscall_Envs },
{ &os_Args, sizeof os_Args },
{ nil, 0 } },
};
static void
TestAtomic64(void)
{
uint64 z64, x64;
z64 = 42;
x64 = 0;
PREFETCH(&z64);
if(runtime_cas64(&z64, &x64, 1))
runtime_throw("cas64 failed");
if(x64 != 42)
runtime_throw("cas64 failed");
if(!runtime_cas64(&z64, &x64, 1))
runtime_throw("cas64 failed");
if(x64 != 42 || z64 != 1)
runtime_throw("cas64 failed");
if(runtime_atomicload64(&z64) != 1)
runtime_throw("load64 failed");
runtime_atomicstore64(&z64, (1ull<<40)+1);
if(runtime_atomicload64(&z64) != (1ull<<40)+1)
runtime_throw("store64 failed");
if(runtime_xadd64(&z64, (1ull<<40)+1) != (2ull<<40)+2)
runtime_throw("xadd64 failed");
if(runtime_atomicload64(&z64) != (2ull<<40)+2)
runtime_throw("xadd64 failed");
if(runtime_xchg64(&z64, (3ull<<40)+3) != (2ull<<40)+2)
runtime_throw("xchg64 failed");
if(runtime_atomicload64(&z64) != (3ull<<40)+3)
runtime_throw("xchg64 failed");
}
void
runtime_check(void)
{
__go_register_gc_roots(&runtime_roots);
TestAtomic64();
}
uint32
runtime_fastrand1(void)
{
M *m;
uint32 x;
m = runtime_m();
x = m->fastrand;
x += x;
if(x & 0x80000000L)
x ^= 0x88888eefUL;
m->fastrand = x;
return x;
}
int64
runtime_cputicks(void)
{
#if defined(__386__) || defined(__x86_64__)
uint32 low, high;
asm("rdtsc" : "=a" (low), "=d" (high));
return (int64)(((uint64)high << 32) | (uint64)low);
#else
// FIXME: implement for other processors.
return 0;
#endif
}
bool
runtime_showframe(String s, bool current)
{
static int32 traceback = -1;
if(current && runtime_m()->throwing > 0)
return 1;
if(traceback < 0)
traceback = runtime_gotraceback(nil);
return traceback > 1 || (__builtin_memchr(s.str, '.', s.len) != nil && __builtin_memcmp(s.str, "runtime.", 7) != 0);
}
static Lock ticksLock;
static int64 ticks;
int64
runtime_tickspersecond(void)
{
int64 res, t0, t1, c0, c1;
res = (int64)runtime_atomicload64((uint64*)&ticks);
if(res != 0)
return ticks;
runtime_lock(&ticksLock);
res = ticks;
if(res == 0) {
t0 = runtime_nanotime();
c0 = runtime_cputicks();
runtime_usleep(100*1000);
t1 = runtime_nanotime();
c1 = runtime_cputicks();
if(t1 == t0)
t1++;
res = (c1-c0)*1000*1000*1000/(t1-t0);
if(res == 0)
res++;
runtime_atomicstore64((uint64*)&ticks, res);
}
runtime_unlock(&ticksLock);
return res;
}
int64 runtime_pprof_runtime_cyclesPerSecond(void)
__asm__ (GOSYM_PREFIX "runtime_pprof.runtime_cyclesPerSecond");
int64
runtime_pprof_runtime_cyclesPerSecond(void)
{
return runtime_tickspersecond();
}
// Called to initialize a new m (including the bootstrap m).
// Called on the parent thread (main thread in case of bootstrap), can allocate memory.
void
runtime_mpreinit(M *mp)
{
mp->gsignal = runtime_malg(32*1024, &mp->gsignalstack, &mp->gsignalstacksize); // OS X wants >=8K, Linux >=2K
}
// Called to initialize a new m (including the bootstrap m).
// Called on the new thread, can not allocate memory.
void
runtime_minit(void)
{
M* m;
sigset_t sigs;
// Initialize signal handling.
m = runtime_m();
runtime_signalstack(m->gsignalstack, m->gsignalstacksize);
if (sigemptyset(&sigs) != 0)
runtime_throw("sigemptyset");
sigprocmask(SIG_SETMASK, &sigs, nil);
}
// Called from dropm to undo the effect of an minit.
void
runtime_unminit(void)
{
runtime_signalstack(nil, 0);
}
void
runtime_signalstack(byte *p, int32 n)
{
stack_t st;
st.ss_sp = p;
st.ss_size = n;
st.ss_flags = 0;
if(p == nil)
st.ss_flags = SS_DISABLE;
if(sigaltstack(&st, nil) < 0)
*(int *)0xf1 = 0xf1;
}