mirror of git://gcc.gnu.org/git/gcc.git
115 lines
3.3 KiB
C
115 lines
3.3 KiB
C
// 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.
|
|
|
|
// Stack scanning code for the garbage collector.
|
|
|
|
#include "runtime.h"
|
|
|
|
#ifdef USING_SPLIT_STACK
|
|
|
|
extern void * __splitstack_find (void *, void *, size_t *, void **, void **,
|
|
void **);
|
|
|
|
extern void * __splitstack_find_context (void *context[10], size_t *, void **,
|
|
void **, void **);
|
|
|
|
#endif
|
|
|
|
// Calling unwind_init in doscanstack only works if it does not do a
|
|
// tail call to doscanstack1.
|
|
#pragma GCC optimize ("-fno-optimize-sibling-calls")
|
|
|
|
extern void scanstackblock(void *addr, uintptr size, void *gcw)
|
|
__asm__("runtime.scanstackblock");
|
|
|
|
void doscanstack(G*, void*)
|
|
__asm__("runtime.doscanstack");
|
|
|
|
static void doscanstack1(G*, void*)
|
|
__attribute__ ((noinline));
|
|
|
|
// Scan gp's stack, passing stack chunks to scanstackblock.
|
|
void doscanstack(G *gp, void* gcw) {
|
|
// Save registers on the stack, so that if we are scanning our
|
|
// own stack we will see them.
|
|
__builtin_unwind_init();
|
|
flush_registers_to_secondary_stack();
|
|
|
|
doscanstack1(gp, gcw);
|
|
}
|
|
|
|
// Scan gp's stack after saving registers.
|
|
static void doscanstack1(G *gp, void *gcw) {
|
|
#ifdef USING_SPLIT_STACK
|
|
void* sp;
|
|
size_t spsize;
|
|
void* next_segment;
|
|
void* next_sp;
|
|
void* initial_sp;
|
|
|
|
if (gp == runtime_g()) {
|
|
// Scanning our own stack.
|
|
sp = __splitstack_find(nil, nil, &spsize, &next_segment,
|
|
&next_sp, &initial_sp);
|
|
} else {
|
|
// Scanning another goroutine's stack.
|
|
// The goroutine is usually asleep (the world is stopped).
|
|
|
|
// The exception is that if the goroutine is about to enter or might
|
|
// have just exited a system call, it may be executing code such
|
|
// as schedlock and may have needed to start a new stack segment.
|
|
// Use the stack segment and stack pointer at the time of
|
|
// the system call instead, since that won't change underfoot.
|
|
if(gp->gcstack != 0) {
|
|
sp = (void*)(gp->gcstack);
|
|
spsize = gp->gcstacksize;
|
|
next_segment = (void*)(gp->gcnextsegment);
|
|
next_sp = (void*)(gp->gcnextsp);
|
|
initial_sp = (void*)(gp->gcinitialsp);
|
|
} else {
|
|
sp = __splitstack_find_context((void**)(&gp->stackcontext[0]),
|
|
&spsize, &next_segment,
|
|
&next_sp, &initial_sp);
|
|
}
|
|
}
|
|
if(sp != nil) {
|
|
scanstackblock(sp, (uintptr)(spsize), gcw);
|
|
while((sp = __splitstack_find(next_segment, next_sp,
|
|
&spsize, &next_segment,
|
|
&next_sp, &initial_sp)) != nil)
|
|
scanstackblock(sp, (uintptr)(spsize), gcw);
|
|
}
|
|
#else
|
|
byte* bottom;
|
|
byte* top;
|
|
byte* nextsp2;
|
|
byte* initialsp2;
|
|
|
|
if(gp == runtime_g()) {
|
|
// Scanning our own stack.
|
|
bottom = (byte*)&gp;
|
|
nextsp2 = secondary_stack_pointer();
|
|
} else {
|
|
// Scanning another goroutine's stack.
|
|
// The goroutine is usually asleep (the world is stopped).
|
|
bottom = (void*)gp->gcnextsp;
|
|
if(bottom == nil)
|
|
return;
|
|
nextsp2 = (void*)gp->gcnextsp2;
|
|
}
|
|
top = (byte*)(void*)(gp->gcinitialsp) + gp->gcstacksize;
|
|
if(top > bottom)
|
|
scanstackblock(bottom, (uintptr)(top - bottom), gcw);
|
|
else
|
|
scanstackblock(top, (uintptr)(bottom - top), gcw);
|
|
if (nextsp2 != nil) {
|
|
initialsp2 = (byte*)(void*)(gp->gcinitialsp2);
|
|
if(initialsp2 > nextsp2)
|
|
scanstackblock(nextsp2, (uintptr)(initialsp2 - nextsp2), gcw);
|
|
else
|
|
scanstackblock(initialsp2, (uintptr)(nextsp2 - initialsp2), gcw);
|
|
}
|
|
#endif
|
|
}
|