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path: root/src/pkg/runtime/amd64/traceback.c
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Diffstat (limited to 'src/pkg/runtime/amd64/traceback.c')
-rw-r--r--src/pkg/runtime/amd64/traceback.c124
1 files changed, 89 insertions, 35 deletions
diff --git a/src/pkg/runtime/amd64/traceback.c b/src/pkg/runtime/amd64/traceback.c
index 86e96f348..d3aae0db9 100644
--- a/src/pkg/runtime/amd64/traceback.c
+++ b/src/pkg/runtime/amd64/traceback.c
@@ -8,6 +8,8 @@
static uintptr isclosureentry(uintptr);
void runtime·deferproc(void);
void runtime·newproc(void);
+void runtime·newstack(void);
+void runtime·morestack(void);
// This code is also used for the 386 tracebacks.
// Use uintptr for an appropriate word-sized integer.
@@ -17,15 +19,32 @@ void runtime·newproc(void);
// A little clunky to merge the two but avoids duplicating
// the code and all its subtlety.
static int32
-gentraceback(byte *pc0, byte *sp, G *g, int32 skip, uintptr *pcbuf, int32 m)
+gentraceback(byte *pc0, byte *sp, G *g, int32 skip, uintptr *pcbuf, int32 max)
{
byte *p;
- int32 i, n, iter, nascent;
- uintptr pc, tracepc, *fp;
+ int32 i, n, iter, sawnewstack;
+ uintptr pc, lr, tracepc;
+ byte *fp;
Stktop *stk;
Func *f;
-
+
pc = (uintptr)pc0;
+ lr = 0;
+ fp = nil;
+
+ // If the PC is goexit, the goroutine hasn't started yet.
+ if(pc0 == g->sched.pc && sp == g->sched.sp && pc0 == (byte*)runtime·goexit) {
+ fp = sp;
+ lr = pc;
+ pc = (uintptr)g->entry;
+ }
+
+ // If the PC is zero, it's likely a nil function call.
+ // Start in the caller's frame.
+ if(pc == 0) {
+ pc = lr;
+ lr = 0;
+ }
// If the PC is zero, it's likely a nil function call.
// Start in the caller's frame.
@@ -33,26 +52,29 @@ gentraceback(byte *pc0, byte *sp, G *g, int32 skip, uintptr *pcbuf, int32 m)
pc = *(uintptr*)sp;
sp += sizeof(uintptr);
}
-
- nascent = 0;
- if(pc0 == g->sched.pc && sp == g->sched.sp && pc0 == (byte*)runtime·goexit) {
- // Hasn't started yet. g->sched is set up for goexit
- // but goroutine will start at g->entry.
- nascent = 1;
- pc = (uintptr)g->entry;
- }
-
+
n = 0;
+ sawnewstack = 0;
stk = (Stktop*)g->stackbase;
- for(iter = 0; iter < 100 && n < m; iter++) { // iter avoids looping forever
+ for(iter = 0; iter < 100 && n < max; iter++) { // iter avoids looping forever
+ // Typically:
+ // pc is the PC of the running function.
+ // sp is the stack pointer at that program counter.
+ // fp is the frame pointer (caller's stack pointer) at that program counter, or nil if unknown.
+ // stk is the stack containing sp.
+ // The caller's program counter is lr, unless lr is zero, in which case it is *(uintptr*)sp.
+
if(pc == (uintptr)runtime·lessstack) {
// Hit top of stack segment. Unwind to next segment.
pc = (uintptr)stk->gobuf.pc;
sp = stk->gobuf.sp;
+ lr = 0;
+ fp = nil;
+ if(pcbuf == nil)
+ runtime·printf("----- stack segment boundary -----\n");
stk = (Stktop*)stk->stackbase;
continue;
}
-
if(pc <= 0x1000 || (f = runtime·findfunc(pc)) == nil) {
// Dangerous, but worthwhile: see if this is a closure:
// ADDQ $wwxxyyzz, SP; RET
@@ -66,17 +88,32 @@ gentraceback(byte *pc0, byte *sp, G *g, int32 skip, uintptr *pcbuf, int32 m)
sp += *(uint32*)(p+2);
pc = *(uintptr*)sp;
sp += sizeof(uintptr);
+ lr = 0;
+ fp = nil;
continue;
}
- if(nascent && (pc = isclosureentry(pc)) != 0)
+ // Closure at top of stack, not yet started.
+ if(lr == (uintptr)runtime·goexit && (pc = isclosureentry(pc)) != 0) {
+ fp = sp;
continue;
+ }
- // Unknown pc; stop.
+ // Unknown pc: stop.
break;
}
- // Found an actual function worth reporting.
+ // Found an actual function.
+ if(fp == nil) {
+ fp = sp;
+ if(pc > f->entry && f->frame >= sizeof(uintptr))
+ fp += f->frame - sizeof(uintptr);
+ if(lr == 0)
+ lr = *(uintptr*)fp;
+ fp += sizeof(uintptr);
+ } else if(lr == 0)
+ lr = *(uintptr*)fp;
+
if(skip > 0)
skip--;
else if(pcbuf != nil)
@@ -93,15 +130,10 @@ gentraceback(byte *pc0, byte *sp, G *g, int32 skip, uintptr *pcbuf, int32 m)
tracepc--;
runtime·printf(" %S:%d\n", f->src, runtime·funcline(f, tracepc));
runtime·printf("\t%S(", f->name);
- fp = (uintptr*)sp;
- if(f->frame < sizeof(uintptr))
- fp++;
- else
- fp += f->frame/sizeof(uintptr);
for(i = 0; i < f->args; i++) {
if(i != 0)
runtime·prints(", ");
- runtime·printhex(fp[i]);
+ runtime·printhex(((uintptr*)fp)[i]);
if(i >= 4) {
runtime·prints(", ...");
break;
@@ -111,20 +143,32 @@ gentraceback(byte *pc0, byte *sp, G *g, int32 skip, uintptr *pcbuf, int32 m)
n++;
}
- if(nascent) {
- pc = (uintptr)g->sched.pc;
- sp = g->sched.sp;
- nascent = 0;
+ if(f->entry == (uintptr)runtime·deferproc || f->entry == (uintptr)runtime·newproc)
+ fp += 2*sizeof(uintptr);
+
+ if(f->entry == (uintptr)runtime·newstack)
+ sawnewstack = 1;
+
+ if(pcbuf == nil && f->entry == (uintptr)runtime·morestack && g == m->g0 && sawnewstack) {
+ // The fact that we saw newstack means that morestack
+ // has managed to record its information in m, so we can
+ // use it to keep unwinding the stack.
+ runtime·printf("----- morestack called from goroutine %d -----\n", m->curg->goid);
+ pc = (uintptr)m->morepc;
+ sp = m->morebuf.sp - sizeof(void*);
+ lr = (uintptr)m->morebuf.pc;
+ fp = m->morebuf.sp;
+ sawnewstack = 0;
+ g = m->curg;
+ stk = (Stktop*)g->stackbase;
continue;
}
- if(f->frame < sizeof(uintptr)) // assembly functions lie
- sp += sizeof(uintptr);
- else
- sp += f->frame;
- pc = *((uintptr*)sp - 1);
- if(f->entry == (uintptr)runtime·deferproc || f->entry == (uintptr)runtime·newproc)
- sp += 2*sizeof(uintptr);
+ // Unwind to next frame.
+ pc = lr;
+ lr = 0;
+ sp = fp;
+ fp = nil;
}
return n;
}
@@ -156,7 +200,17 @@ isclosureentry(uintptr pc)
p = (byte*)pc;
if(p < runtime·mheap.arena_start || p+32 > runtime·mheap.arena_used)
return 0;
+
+ if(*p == 0xe8) {
+ // CALL fn
+ return pc+5+*(int32*)(p+1);
+ }
+ if(sizeof(uintptr) == 8 && p[0] == 0x48 && p[1] == 0xb9 && p[10] == 0xff && p[11] == 0xd1) {
+ // MOVQ $fn, CX; CALL *CX
+ return *(uintptr*)(p+2);
+ }
+
// SUBQ $siz, SP
if((sizeof(uintptr) == 8 && *p++ != 0x48) || *p++ != 0x81 || *p++ != 0xec)
return 0;
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