makes stack traces work for segmented stacks

SVN=125371

diff --git a/src/runtime/rt0_amd64.s b/src/runtime/rt0_amd64.s
index 18559eb78a821c93c252bc30bd2887a22b2e3beb..21c1aa9f1d0dd1f26bcf492db574faa810dedbee 100644 (file)
--- a/src/runtime/rt0_amd64.s
+++ b/src/runtime/rt0_amd64.s
@@ -175,7 +175,16 @@ easy:
        ADDQ    $8, SP
        RET
 
+// marker.  must be here; used by traceback() to discover calls to _morestack
+TEXT _endmorestack(SB), 7, $-8
+       RET
+
 TEXT   FLUSH(SB),7,$-8
        RET
 
+TEXT   getu(SB),7,$-8
+       MOVQ    R15, AX
+       RET
+
+
 GLOBL  peruser<>(SB),$64

diff --git a/src/runtime/rt1_amd64_darwin.c b/src/runtime/rt1_amd64_darwin.c
index b39c298ee75a4f6993f3b35b2a5dcc982f2933ed..9d03ce05590f85663c8ee0d2f29b6122c4f1e7be 100644 (file)
--- a/src/runtime/rt1_amd64_darwin.c
+++ b/src/runtime/rt1_amd64_darwin.c
@@ -145,11 +145,11 @@ sighandler(int32 sig, siginfo *info, void *context)
         _STRUCT_X86_THREAD_STATE64 *ss = get___ss(uc_mcontext);
 
        prints("\nFaulting address: 0x");  sys·printpointer(info->si_addr);
-        prints("\npc: 0x");  sys·printpointer((void *)ss->__rip);
-        prints("\n\n");
+       prints("\npc: 0x");  sys·printpointer((void *)ss->__rip);
+       prints("\n\n");
         
-       traceback((void *)ss->__rip, (void *)ss->__rsp);
-        print_thread_state(ss);
+       traceback((void *)ss->__rip, (void *)ss->__rsp, (void*)ss->__r15);
+       print_thread_state(ss);
         
        sys·exit(2);
 }

diff --git a/src/runtime/rt1_amd64_linux.c b/src/runtime/rt1_amd64_linux.c
index e7dfbc79b45e5a014f817f5fbfd69a300459338f..b31b89aa68ebeaf4ac7eef4535c5eaf4e4ff29ce 100644 (file)
--- a/src/runtime/rt1_amd64_linux.c
+++ b/src/runtime/rt1_amd64_linux.c
@@ -152,7 +152,7 @@ sighandler(int32 sig, siginfo* info, void** context)
         prints("\npc: 0x");  sys·printpointer((void *)sc->rip);
         prints("\n\n");
         
-       traceback((void *)sc->rip, (void *)sc->rsp);
+       traceback((void *)sc->rip, (void *)sc->rsp, (void *)sc->r15);
         print_sigcontext(sc);
 
        sys·breakpoint();

diff --git a/src/runtime/rt2_amd64.c b/src/runtime/rt2_amd64.c
index f544ddd213944e153cca16ee9a688f781369b4aa..795285d7de52636a775e92d84e3f3577efb01a74 100644 (file)
--- a/src/runtime/rt2_amd64.c
+++ b/src/runtime/rt2_amd64.c
@@ -8,22 +8,54 @@ extern int32  debug;
 
 static int8 spmark[] = "\xa7\xf1\xd9\x2a\x82\xc8\xd8\xfe";
 
+typedef struct U U;
+struct U {
+       uint8*  stackguard;
+       uint8*  stackbase;
+       uint8*  istackguard;
+       uint8*  istackbase;
+};
+
+typedef struct Stktop Stktop;
+struct Stktop {
+       uint8*  oldbase;
+       uint8*  oldsp;
+       uint8*  magic;
+       uint8*  oldguard;
+};
+
+extern void _morestack();
+extern void _endmorestack();
+
 void
-traceback(uint8 *pc, uint8 *sp)
+traceback(uint8 *pc, uint8 *sp, void* r15)
 {
        int32 spoff;
        int8* spp;
+       uint8* callpc;
        int32 counter;
        int32 i;
        int8* name;
+       U u;
+       Stktop *stktop;
 
+       // store local copy of per-process data block that we can write as we unwind
+       mcpy((byte*)&u, (byte*)r15, sizeof(U));
 
        counter = 0;
        name = "panic";
        for(;;){
-               prints("0x");
-               sys·printpointer(pc);
-               prints("?zi\n");
+               callpc = pc;
+               if((uint8*)_morestack < pc && pc < (uint8*)_endmorestack) {
+                       // call site in _morestack(); pop to earlier stack block to get true caller
+                       stktop = (Stktop*)u.stackbase;
+                       u.stackbase = stktop->oldbase;
+                       u.stackguard = stktop->oldguard;
+                       sp = stktop->oldsp;
+                       pc = ((uint8**)sp)[1];
+                       sp += 16;  // two irrelevant calls on stack - morestack, plus the call morestack made
+                       continue;
+               }
                /* find SP offset by stepping back through instructions to SP offset marker */
                while(pc > (uint8*)0x1000+sizeof spmark-1) {
                        for(spp = spmark; *spp != '\0' && *pc++ == (uint8)*spp++; )
@@ -43,7 +75,11 @@ traceback(uint8 *pc, uint8 *sp)
                }
                if((pc = ((uint8**)sp)[-1]) <= (uint8*)0x1000)
                        break;
-               /* print args for this frame */
+
+               /* print this frame */
+               prints("0x");
+               sys·printpointer(callpc);
+               prints("?zi\n");
                prints("\t");
                prints(name);
                prints("(");

diff --git a/src/runtime/runtime.c b/src/runtime/runtime.c
index f1d7fc385e3b84ce9b59657e66e1fc6890f0afec..3f9e8c27418842d4e3f9790ac1bb4bd2dfc3256d 100644 (file)
--- a/src/runtime/runtime.c
+++ b/src/runtime/runtime.c
@@ -18,7 +18,7 @@ sys·panicl(int32 lno)
        sys·printpc(&lno);
        prints("\n");
        sp = (uint8*)&lno;
-       traceback(sys·getcallerpc(&lno), sp);
+       traceback(sys·getcallerpc(&lno), sp, getu());
        sys·breakpoint();
        sys·exit(2);
 }

diff --git a/src/runtime/runtime.h b/src/runtime/runtime.h
index bc183815f4e1c0fd40f8da03f2f6a5a23e31e72b..f64353e22aa870c7034ad9e5b6f2dffcdf18eaba 100644 (file)
--- a/src/runtime/runtime.h
+++ b/src/runtime/runtime.h
@@ -93,13 +93,14 @@ extern int32 debug;
  * very low level c-called
  */
 void   FLUSH(void*);
+void*  getu(void);
 void   throw(int8*);
 void   prints(int8*);
 void   mcpy(byte*, byte*, uint32);
 void*  mal(uint32);
 uint32 cmpstring(string, string);
 void   initsig(void);
-void   traceback(uint8 *pc, uint8 *sp);
+void   traceback(uint8 *pc, uint8 *sp, void* up);
 int32  open(byte*, int32);
 int32  read(int32, void*, int32);
 void   close(int32);