1 files changed, 146 insertions, 0 deletions
diff --git a/src/pkg/runtime/amd64/traceback.c b/src/pkg/runtime/amd64/traceback.c
new file mode 100644
index 000000000..16d7bed72
--- /dev/null
+++ b/src/pkg/runtime/amd64/traceback.c
@@ -0,0 +1,146 @@
+// 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 "runtime.h"
+
+void
+traceback(byte *pc0, byte *sp, G *g)
+{
+	Stktop *stk;
+	uint64 pc;
+	int32 i, n;
+	Func *f;
+	byte *p;
+
+	pc = (uint64)pc0;
+
+	// If the PC is zero, it's likely a nil function call.
+	// Start in the caller's frame.
+	if(pc == 0) {
+		pc = *(uint64*)sp;
+		sp += 8;
+	}
+
+	stk = (Stktop*)g->stackbase;
+	for(n=0; n<100; n++) {
+		while(pc == (uint64)retfromnewstack) {
+			// pop to earlier stack block
+			sp = stk->oldsp;
+			stk = (Stktop*)stk->oldbase;
+			pc = *(uint64*)(sp+8);
+			sp += 16;	// two irrelevant calls on stack: morestack plus its call
+		}
+		f = findfunc(pc);
+		if(f == nil) {
+			// dangerous, but poke around to see if it is a closure
+			p = (byte*)pc;
+			// ADDQ $xxx, SP; RET
+			if(p[0] == 0x48 && p[1] == 0x81 && p[2] == 0xc4 && p[7] == 0xc3) {
+				sp += *(uint32*)(p+3) + 8;
+				pc = *(uint64*)(sp - 8);
+				if(pc <= 0x1000)
+					return;
+				continue;
+			}
+			printf("%p unknown pc\n", pc);
+			return;
+		}
+		if(f->frame < 8)	// assembly funcs say 0 but lie
+			sp += 8;
+		else
+			sp += f->frame;
+
+		// print this frame
+		//	main+0xf /home/rsc/go/src/runtime/x.go:23
+		//		main(0x1, 0x2, 0x3)
+		printf("%S", f->name);
+		if(pc > f->entry)
+			printf("+%X", pc - f->entry);
+		printf(" %S:%d\n", f->src, funcline(f, pc-1));	// -1 to get to CALL instr.
+		printf("\t%S(", f->name);
+		for(i = 0; i < f->args; i++) {
+			if(i != 0)
+				prints(", ");
+			sys·printhex(((uint32*)sp)[i]);
+			if(i >= 4) {
+				prints(", ...");
+				break;
+			}
+		}
+		prints(")\n");
+
+		pc = *(uint64*)(sp-8);
+		if(pc <= 0x1000)
+			return;
+	}
+	prints("...\n");
+}
+
+// func caller(n int) (pc uint64, file string, line int, ok bool)
+void
+runtime·Caller(int32 n, uint64 retpc, String retfile, int32 retline, bool retbool)
+{
+	uint64 pc;
+	byte *sp;
+	byte *p;
+	Stktop *stk;
+	Func *f;
+
+	// our caller's pc, sp.
+	sp = (byte*)&n;
+	pc = *(uint64*)(sp-8);
+	if((f = findfunc(pc)) == nil) {
+	error:
+		retpc = 0;
+		retline = 0;
+		retfile = emptystring;
+		retbool = false;
+		FLUSH(&retpc);
+		FLUSH(&retfile);
+		FLUSH(&retline);
+		FLUSH(&retbool);
+		return;
+	}
+
+	// now unwind n levels
+	stk = (Stktop*)g->stackbase;
+	while(n-- > 0) {
+		while(pc == (uint64)retfromnewstack) {
+			sp = stk->oldsp;
+			stk = (Stktop*)stk->oldbase;
+			pc = *(uint64*)(sp+8);
+			sp += 16;
+		}
+
+		if(f->frame < 8)	// assembly functions lie
+			sp += 8;
+		else
+			sp += f->frame;
+
+	loop:
+		pc = *(uint64*)(sp-8);
+		if(pc <= 0x1000 || (f = findfunc(pc)) == nil) {
+			// dangerous, but let's try this.
+			// see if it is a closure.
+			p = (byte*)pc;
+			// ADDQ $xxx, SP; RET
+			if(p[0] == 0x48 && p[1] == 0x81 && p[2] == 0xc4 && p[7] == 0xc3) {
+				sp += *(uint32*)(p+3) + 8;
+				goto loop;
+			}
+			goto error;
+		}
+	}
+
+	retpc = pc;
+	retfile = f->src;
+	retline = funcline(f, pc-1);
+	retbool = true;
+	FLUSH(&retpc);
+	FLUSH(&retfile);
+	FLUSH(&retline);
+	FLUSH(&retbool);
+}
+
+