// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
-#include "runtime.h"
-#include "arch_GOARCH.h"
-#include "stack.h"
-#include "cgocall.h"
-#include "race.h"
-#include "../../cmd/ld/textflag.h"
-
// Cgo call and callback support.
//
// To call into the C function f from Go, the cgo-generated code calls
//
// runtime.cgocall (below) locks g to m, calls entersyscall
// so as not to block other goroutines or the garbage collector,
-// and then calls runtime.asmcgocall(_cgo_Cfunc_f, frame).
+// and then calls runtime.asmcgocall(_cgo_Cfunc_f, frame).
//
// runtime.asmcgocall (in asm_$GOARCH.s) switches to the m->g0 stack
// (assumed to be an operating system-allocated stack, so safe to run
// _cgoexp_GoF immediately returns to crosscall2, which restores the
// callee-save registers for gcc and returns to GoF, which returns to f.
-void *_cgo_init; /* filled in by dynamic linker when Cgo is available */
-static int64 cgosync; /* represents possible synchronization in C code */
+package runtime
-static void unwindm(void);
+import "unsafe"
// Call from Go to C.
-
-static void endcgo(void);
-static FuncVal endcgoV = { endcgo };
-
-void
-runtime·cgocall(void (*fn)(void*), void *arg)
-{
- runtime·cgocall_errno(fn, arg);
+func cgocall(fn, arg unsafe.Pointer) {
+ cgocall_errno(fn, arg)
}
-int32
-runtime·cgocall_errno(void (*fn)(void*), void *arg)
-{
- Defer d;
- int32 errno;
-
- if(!runtime·iscgo && !Solaris && !Windows)
- runtime·throw("cgocall unavailable");
+func cgocall_errno(fn, arg unsafe.Pointer) int32 {
+ if !iscgo && GOOS != "solaris" && GOOS != "windows" {
+ gothrow("cgocall unavailable")
+ }
- if(fn == 0)
- runtime·throw("cgocall nil");
+ if fn == nil {
+ gothrow("cgocall nil")
+ }
- if(raceenabled)
- runtime·racereleasemerge(&cgosync);
+ if raceenabled {
+ racereleasemerge(unsafe.Pointer(&racecgosync))
+ }
// Create an extra M for callbacks on threads not created by Go on first cgo call.
- if(runtime·needextram && runtime·cas(&runtime·needextram, 1, 0))
- runtime·newextram();
-
- g->m->ncgocall++;
+ if needextram == 1 && cas(&needextram, 1, 0) {
+ newextram()
+ }
/*
- * Mutex g to m to ensure we stay on the same stack if we do a
+ * Lock g to m to ensure we stay on the same stack if we do a
* cgo callback. Add entry to defer stack in case of panic.
*/
- runtime·lockOSThread();
- d.fn = &endcgoV;
- d.siz = 0;
- d.link = g->defer;
- d.argp = NoArgs;
- d.special = true;
- g->defer = &d;
-
- g->m->ncgo++;
+ lockOSThread()
+ mp := getg().m
+ mp.ncgocall++
+ mp.ncgo++
+ defer endcgo(mp)
/*
* Announce we are entering a system call
* so it is safe to call while "in a system call", outside
* the $GOMAXPROCS accounting.
*/
- runtime·entersyscall();
- errno = runtime·asmcgocall_errno(fn, arg);
- runtime·exitsyscall();
-
- if(g->defer != &d || d.fn != &endcgoV)
- runtime·throw("runtime: bad defer entry in cgocallback");
- g->defer = d.link;
- endcgo();
-
- return errno;
+ entersyscall()
+ errno := asmcgocall_errno(fn, arg)
+ exitsyscall()
+
+ return errno
}
-static void
-endcgo(void)
-{
- runtime·unlockOSThread();
- g->m->ncgo--;
- if(g->m->ncgo == 0) {
+func endcgo(mp *m) {
+ mp.ncgo--
+ if mp.ncgo == 0 {
// We are going back to Go and are not in a recursive
// call. Let the GC collect any memory allocated via
// _cgo_allocate that is no longer referenced.
- g->m->cgomal = nil;
+ mp.cgomal = nil
}
- if(raceenabled)
- runtime·raceacquire(&cgosync);
+ if raceenabled {
+ raceacquire(unsafe.Pointer(&racecgosync))
+ }
+
+ unlockOSThread() // invalidates mp
}
// Helper functions for cgo code.
-void (*_cgo_malloc)(void*);
-void (*_cgo_free)(void*);
-
-void*
-runtime·cmalloc(uintptr n)
-{
- struct {
- uint64 n;
- void *ret;
- } a;
-
- a.n = n;
- a.ret = nil;
- runtime·cgocall(_cgo_malloc, &a);
- if(a.ret == nil)
- runtime·throw("runtime: C malloc failed");
- return a.ret;
+// Filled by schedinit from corresponding C variables,
+// which are in turn filled in by dynamic linker when Cgo is available.
+var cgoMalloc, cgoFree unsafe.Pointer
+
+func cmalloc(n uintptr) unsafe.Pointer {
+ var args struct {
+ n uint64
+ ret unsafe.Pointer
+ }
+ args.n = uint64(n)
+ cgocall(cgoMalloc, unsafe.Pointer(&args))
+ if args.ret == nil {
+ gothrow("C malloc failed")
+ }
+ return args.ret
}
-void
-runtime·cfree(void *p)
-{
- runtime·cgocall(_cgo_free, p);
+func cfree(p unsafe.Pointer) {
+ cgocall(cgoFree, p)
}
// Call from C back to Go.
-
-static FuncVal unwindmf = {unwindm};
-
-typedef struct CallbackArgs CallbackArgs;
-struct CallbackArgs
-{
- FuncVal *fn;
- void *arg;
- uintptr argsize;
-};
-
-// Location of callback arguments depends on stack frame layout
-// and size of stack frame of cgocallback_gofunc.
-
-// On arm, stack frame is two words and there's a saved LR between
-// SP and the stack frame and between the stack frame and the arguments.
-#ifdef GOARCH_arm
-#define CBARGS (CallbackArgs*)((byte*)g->m->g0->sched.sp+4*sizeof(void*))
-#endif
-
-// On amd64, stack frame is one word, plus caller PC.
-#ifdef GOARCH_amd64
-#define CBARGS (CallbackArgs*)((byte*)g->m->g0->sched.sp+2*sizeof(void*))
-#endif
-
-// Unimplemented on amd64p32
-#ifdef GOARCH_amd64p32
-#define CBARGS (CallbackArgs*)(nil)
-#endif
-
-// On 386, stack frame is three words, plus caller PC.
-#ifdef GOARCH_386
-#define CBARGS (CallbackArgs*)((byte*)g->m->g0->sched.sp+4*sizeof(void*))
-#endif
-
-void runtime·cgocallbackg1(void);
-
-#pragma textflag NOSPLIT
-void
-runtime·cgocallbackg(void)
-{
- if(g != g->m->curg) {
- runtime·prints("runtime: bad g in cgocallback");
- runtime·exit(2);
+//go:nosplit
+func cgocallbackg() {
+ if gp := getg(); gp != gp.m.curg {
+ println("runtime: bad g in cgocallback")
+ exit(2)
}
- runtime·exitsyscall(); // coming out of cgo call
- runtime·cgocallbackg1();
- runtime·entersyscall(); // going back to cgo call
+ exitsyscall() // coming out of cgo call
+ cgocallbackg1()
+ entersyscall() // going back to cgo call
}
-void
-runtime·cgocallbackg1(void)
-{
- CallbackArgs *cb;
- Defer d;
-
- if(g->m->needextram) {
- g->m->needextram = 0;
- runtime·newextram();
+func cgocallbackg1() {
+ gp := getg()
+ if gp.m.needextram {
+ gp.m.needextram = false
+ newextram()
}
// Add entry to defer stack in case of panic.
- d.fn = &unwindmf;
- d.siz = 0;
- d.link = g->defer;
- d.argp = NoArgs;
- d.special = true;
- g->defer = &d;
+ restore := true
+ defer unwindm(&restore)
+
+ if raceenabled {
+ raceacquire(unsafe.Pointer(&racecgosync))
+ }
- if(raceenabled)
- runtime·raceacquire(&cgosync);
+ type args struct {
+ fn *funcval
+ arg unsafe.Pointer
+ argsize uintptr
+ }
+ var cb *args
+
+ // Location of callback arguments depends on stack frame layout
+ // and size of stack frame of cgocallback_gofunc.
+ sp := gp.m.g0.sched.sp
+ switch GOARCH {
+ default:
+ gothrow("cgocallbackg is unimplemented on arch")
+ case "arm":
+ // On arm, stack frame is two words and there's a saved LR between
+ // SP and the stack frame and between the stack frame and the arguments.
+ cb = (*args)(unsafe.Pointer(sp + 4*ptrSize))
+ case "amd64":
+ // On amd64, stack frame is one word, plus caller PC.
+ cb = (*args)(unsafe.Pointer(sp + 2*ptrSize))
+ case "386":
+ // On 386, stack frame is three words, plus caller PC.
+ cb = (*args)(unsafe.Pointer(sp + 4*ptrSize))
+ }
// Invoke callback.
- cb = CBARGS;
- runtime·newstackcall(cb->fn, cb->arg, cb->argsize);
+ newstackcall(cb.fn, cb.arg, uint32(cb.argsize))
- if(raceenabled)
- runtime·racereleasemerge(&cgosync);
+ if raceenabled {
+ racereleasemerge(unsafe.Pointer(&racecgosync))
+ }
- // Pop defer.
// Do not unwind m->g0->sched.sp.
// Our caller, cgocallback, will do that.
- if(g->defer != &d || d.fn != &unwindmf)
- runtime·throw("runtime: bad defer entry in cgocallback");
- g->defer = d.link;
+ restore = false
}
-static void
-unwindm(void)
-{
+func unwindm(restore *bool) {
+ if !*restore {
+ return
+ }
// Restore sp saved by cgocallback during
// unwind of g's stack (see comment at top of file).
- switch(thechar){
+ mp := acquirem()
+ sched := &mp.g0.sched
+ switch GOARCH {
default:
- runtime·throw("runtime: unwindm not implemented");
- case '8':
- case '6':
- g->m->g0->sched.sp = *(uintptr*)g->m->g0->sched.sp;
- break;
- case '5':
- g->m->g0->sched.sp = *(uintptr*)((byte*)g->m->g0->sched.sp + 4);
- break;
+ gothrow("unwindm not implemented")
+ case "386", "amd64":
+ sched.sp = *(*uintptr)(unsafe.Pointer(sched.sp))
+ case "arm":
+ sched.sp = *(*uintptr)(unsafe.Pointer(sched.sp + 4))
}
+ releasem(mp)
}
-void
-runtime·badcgocallback(void) // called from assembly
-{
- runtime·throw("runtime: misaligned stack in cgocallback");
+// called from assembly
+func badcgocallback() {
+ gothrow("misaligned stack in cgocallback")
}
-void
-runtime·cgounimpl(void) // called from (incomplete) assembly
-{
- runtime·throw("runtime: cgo not implemented");
+// called from (incomplete) assembly
+func cgounimpl() {
+ gothrow("cgo not implemented")
}
-// For cgo-using programs with external linking,
-// export "main" (defined in assembly) so that libc can handle basic
-// C runtime startup and call the Go program as if it were
-// the C main function.
-#pragma cgo_export_static main
+var racecgosync uint64 // represents possible synchronization in C code