runtime: print more detail in adjustframe crash

The logic here is copied from mgc0.c's scanframe.
Mostly it is messages although the minsize code is new
(and I believe necessary).

I am hoping to get more information about the current
arm build failures (or, if it's the minsize thing, fix them).

TBR=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/143180043

diff --git a/src/runtime/stack.c b/src/runtime/stack.c
index 143b645e421bca61c76966cc9e45953647464ec7..b38ee31d48eb8f51ac555a3956df906d4f660cce 100644 (file)
--- a/src/runtime/stack.c
+++ b/src/runtime/stack.c
@@ -463,7 +463,7 @@ adjustframe(Stkframe *frame, void *arg)
        StackMap *stackmap;
        int32 pcdata;
        BitVector bv;
-       uintptr targetpc;
+       uintptr targetpc, size, minsize;
 
        adjinfo = arg;
        targetpc = frame->continpc;
@@ -486,27 +486,47 @@ adjustframe(Stkframe *frame, void *arg)
        if(pcdata == -1)
                pcdata = 0; // in prologue
 
-       // adjust local pointers
-       if((byte*)frame->varp != (byte*)frame->sp) {
+       // Adjust local variables if stack frame has been allocated.
+       size = frame->varp - frame->sp;
+       if(thechar != '6' && thechar != '8')
+               minsize = sizeof(uintptr);
+       else
+               minsize = 0;
+       if(size > minsize) {
                stackmap = runtime·funcdata(f, FUNCDATA_LocalsPointerMaps);
-               if(stackmap == nil)
-                       runtime·throw("no locals info");
-               if(stackmap->n <= 0)
-                       runtime·throw("locals size info only");
+               if(stackmap == nil || stackmap->n <= 0) {
+                       runtime·printf("runtime: frame %s untyped locals %p+%p\n", runtime·funcname(f), (byte*)(frame->varp-size), size);
+                       runtime·throw("missing stackmap");
+               }
+               // Locals bitmap information, scan just the pointers in locals.
+               if(pcdata < 0 || pcdata >= stackmap->n) {
+                       // don't know where we are
+                       runtime·printf("runtime: pcdata is %d and %d locals stack map entries for %s (targetpc=%p)\n",
+                               pcdata, stackmap->n, runtime·funcname(f), targetpc);
+                       runtime·throw("bad symbol table");
+               }
                bv = runtime·stackmapdata(stackmap, pcdata);
+               size = (bv.n * PtrSize) / BitsPerPointer;
                if(StackDebug >= 3)
                        runtime·printf("      locals\n");
-               adjustpointers((byte**)frame->varp - bv.n / BitsPerPointer, &bv, adjinfo, f);
+               adjustpointers((byte**)(frame->varp - size), &bv, adjinfo, f);
        }
-       // adjust inargs and outargs
-       if(frame->arglen != 0) {
+       
+       // Adjust arguments.
+       if(frame->arglen > 0) {
                if(frame->argmap != nil) {
                        bv = *frame->argmap;
                } else {
                        stackmap = runtime·funcdata(f, FUNCDATA_ArgsPointerMaps);
-                       if(stackmap == nil) {
-                               runtime·printf("size %d\n", (int32)frame->arglen);
-                               runtime·throw("no arg info");
+                       if(stackmap == nil || stackmap->n <= 0) {
+                               runtime·printf("runtime: frame %s untyped args %p+%p\n", runtime·funcname(f), frame->argp, (uintptr)frame->arglen);
+                               runtime·throw("missing stackmap");
+                       }
+                       if(pcdata < 0 || pcdata >= stackmap->n) {
+                               // don't know where we are
+                               runtime·printf("runtime: pcdata is %d and %d args stack map entries for %s (targetpc=%p)\n",
+                                       pcdata, stackmap->n, runtime·funcname(f), targetpc);
+                               runtime·throw("bad symbol table");
                        }
                        bv = runtime·stackmapdata(stackmap, pcdata);
                }