code review 906041: runtime: turn divide by zero, nil dereference into panics

src/pkg/runtime/runtime.h

 // 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.
 
 /*
  * basic types
  */
 typedef signed char             int8;
 typedef unsigned char           uint8;
 typedef signed short            int16;
@@ skipping 180 matching lines @@
         int16   status;
         int32   goid;
         uint32  selgen;         // valid sudog pointer
         G*      schedlink;
         bool    readyonstop;
         bool    ispanic;
         M*      m;              // for debuggers, but offset not hard-coded
         M*      lockedm;
         void    (*cgofn)(void*);        // for cgo/ffi
         void    *cgoarg;
+        int32   sig;
+        uintptr sigcode0;
+        uintptr sigcode1;
 };
 struct  M
 {
         // The offsets of these fields are known to (hard-coded in) libmach.
         G*      g0;             // goroutine with scheduling stack
         void    (*morepc)(void);
         void*   morefp; // frame pointer for more stack
         Gobuf   morebuf;        // gobuf arg to morestack
 
         // Fields not known to debuggers.
@@ skipping 50 matching lines @@
 {
         int32   flags;
         int8    *name;
 };
 enum
 {
         SigCatch = 1<<0,
         SigIgnore = 1<<1,
         SigRestart = 1<<2,
         SigQueue = 1<<3,
+        SigPanic = 1<<4,
 };
 
 // NOTE(rsc): keep in sync with extern.go:/type.Func.
 // Eventually, the loaded symbol table should be closer to this form.
 struct  Func
 {
         String  name;
         String  type;   // go type string
         String  src;    // src file name
         Slice   pcln;   // pc/ln tab for this func
@@ skipping 295 matching lines @@
 
 Hchan*  makechan(Type*, uint32);
 void    chansend(Hchan*, void*, bool*);
 void    chanrecv(Hchan*, void*, bool*);
 void    chanclose(Hchan*);
 bool    chanclosed(Hchan*);
 int32   chanlen(Hchan*);
 int32   chancap(Hchan*);
 
 void    ifaceE2I(struct InterfaceType*, Eface, Iface*);