diff mbox

Go patch committed: Mark stub functions with $stub, skip them in runtime.Callers

Message ID CAOyqgcX-vo4pkjyJ1c87wpfryQihD=NHUjuvRo2i5x_yELbWVg@mail.gmail.com
State New
Headers show

Commit Message

Ian Lance Taylor Feb. 3, 2016, 6:54 a.m. UTC 
It's been a long-standing problem in gccgo that the testing package
does not report the correct file/line information when using a method
like t.Error.  This is because the testing type uses an embedded type,
and methods like t.Error are actually inherited from the embedded
type.  This means that the method is a stub.  In the gc toolchain,
stubs are thunks that jump directly to the code and do not remain on
the stack.  In the gccgo toolchain, they do remain on the stack, which
means that code that calls runtime.Caller will see them in places
where the gc toolchain does not.

This patch fixes the problem by marking stub functions with $stub in
their name, and skipping $stub functions in runtime.Caller.
Bootstrapped and ran Go testsuite on x86_64-pc-linux-gnu.  Committed
to mainline.

Ian
diff mbox

Patch

Index: gcc/go/gofrontend/MERGE
===================================================================
--- gcc/go/gofrontend/MERGE	(revision 233097)
+++ gcc/go/gofrontend/MERGE	(working copy)
@@ -1,4 +1,4 @@ 
-a408bef550251926c28673818db2c64302faac1d
+c70e74c116d08c6f2e787551eb1366983815c032
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.
Index: gcc/go/gofrontend/types.cc
===================================================================
--- gcc/go/gofrontend/types.cc	(revision 233097)
+++ gcc/go/gofrontend/types.cc	(working copy)
@@ -9632,13 +9632,14 @@  Type::build_stub_methods(Gogo* gogo, con
 	package = NULL;
       else
 	package = type->named_type()->named_object()->package();
+      std::string stub_name = name + "$stub";
       Named_object* stub;
       if (package != NULL)
-	stub = Named_object::make_function_declaration(name, package,
+	stub = Named_object::make_function_declaration(stub_name, package,
 						       stub_type, location);
       else
 	{
-	  stub = gogo->start_function(name, stub_type, false,
+	  stub = gogo->start_function(stub_name, stub_type, false,
 				      fntype->location());
 	  Type::build_one_stub_method(gogo, m, buf, stub_params,
 				      fntype->is_varargs(), location);
Index: libgo/runtime/go-callers.c
===================================================================
--- libgo/runtime/go-callers.c	(revision 232239)
+++ libgo/runtime/go-callers.c	(working copy)
@@ -74,6 +74,8 @@  callback (void *data, uintptr_t pc, cons
       p = __builtin_strrchr (function, '$');
       if (p != NULL && __builtin_strcmp(p, "$recover") == 0)
 	return 0;
+      if (p != NULL && __builtin_strncmp(p, "$stub", 5) == 0)
+	return 0;
     }
 
   if (arg->skip > 0)