[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, 6 insertions, 0 deletions

diff --git a/llgo/third_party/gofrontend/libgo/runtime/go-reflect-call.c b/llgo/third_party/gofrontend/libgo/runtime/go-reflect-call.c
index 29e814a793f..2a14d6c6add 100644
--- a/llgo/third_party/gofrontend/libgo/runtime/go-reflect-call.c
+++ b/llgo/third_party/gofrontend/libgo/runtime/go-reflect-call.c
@@ -81,6 +81,12 @@ go_results_size (const struct __go_func_type *func)
 
   off = (off + maxalign - 1) & ~ (maxalign - 1);
 
+  // The libffi library doesn't understand a struct with no fields.
+  // We generate a struct with a single field of type void.  When used
+  // as a return value, libffi will think that requires a byte.
+  if (off == 0)
+    off = 1;
+
   return off;
 }