[llgo] Roll gofrontend forward

Switch gofrontend to using go.googlesource.com, and
update to 81eb6a3f425b2158c67ee32c0cc973a72ce9d6be.

There are various changes required to update to the
go 1.5 runtime:

typemap.go is changed to accommodate the change in representation for equal/hash algorithms, and the removal of the zero value/type.
CMakeLists.txt is updated to add the build tree to the package search path, so internal packages, which are not installed, are found.
various files changes due to removal of __go_new_nopointers; the same change as in D11863, but with NoUnwindAttribute added to the added runtime functions which are called with "callOnly".
minor cleanups in ssa.go while investigating issues with unwinding/panic handling.

Differential Revisision: http://reviews.llvm.org/D15188

llvm-svn: 263536

1 files changed, 3 insertions, 1 deletions

diff --git a/llgo/third_party/gofrontend/libgo/runtime/go-caller.c b/llgo/third_party/gofrontend/libgo/runtime/go-caller.c
index ad151ecea8e..d6901e07377 100644
--- a/llgo/third_party/gofrontend/libgo/runtime/go-caller.c
+++ b/llgo/third_party/gofrontend/libgo/runtime/go-caller.c
@@ -166,7 +166,7 @@ Caller (int skip)
 
   runtime_memclr (&ret, sizeof ret);
   n = runtime_callers (skip + 1, &loc, 1, false);
-  if (n < 1)
+  if (n < 1 || loc.pc == 0)
     return ret;
   ret.pc = loc.pc;
   ret.file = loc.filename;
@@ -231,6 +231,8 @@ String runtime_funcname_go (Func *f)
 String
 runtime_funcname_go (Func *f)
 {
+  if (f == NULL)
+    return runtime_gostringnocopy ((const byte *) "");
   return f->name;
 }