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

src/pkg/runtime/linux/thread.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.
 
 #include "runtime.h"
 #include "defs.h"
-#include "signals.h"
 #include "os.h"
 
+extern SigTab sigtab[];
+
 // Linux futex.
 //
 //      futexsleep(uint32 *addr, uint32 val)
 //      futexwakeup(uint32 *addr)
 //
 // Futexsleep atomically checks if *addr == val and if so, sleeps on addr.
 // Futexwakeup wakes up one thread sleeping on addr.
 // Futexsleep is allowed to wake up spuriously.
 
 enum
@@ skipping 243 matching lines @@
 }
 
 // Called to initialize a new m (including the bootstrap m).
 void
 minit(void)
 {
         // Initialize signal handling.
         m->gsignal = malg(32*1024);     // OS X wants >=8K, Linux >=2K
         signalstack(m->gsignal->stackguard, 32*1024);
 }
+
+void
+sigpanic(void)
+{
+        switch(g->sig) {
+        case SIGBUS:
+                if(g->sigcode0 == BUS_ADRERR && g->sigcode1 < 0x1000)
+                        panicstring("invalid memory address or nil pointer dereference");
+                break;
+        case SIGSEGV:
+                if((g->sigcode0 == 0 || g->sigcode0 == SEGV_MAPERR) && g->sigcode1 < 0x1000)
+                        panicstring("invalid memory address or nil pointer dereference");
+                break;
+        case SIGFPE:
+                switch(g->sigcode0) {
+                case FPE_INTDIV:
+                        panicstring("integer divide by zero");
+                case FPE_INTOVF:
+                        panicstring("integer overflow");
+                }
+                panicstring("floating point error");
+        }
+        panicstring(sigtab[g->sig].name);
+}