This is hopefully the last attempt to fix the libgo breakage. This time
around I really think I got to the bottom of the problem. The issue is
that the Go FE defines the __builtin_trap call, but doesn't set the
TREE_THIS_VOLATILE flag on it. That's bad because then this call isn't
gimple_call_noreturn_p and the cgraph cleanup code can't do its job properly.
Bootstrapped/regtested on x86_64-linux. Now, I don't know the Go patch
process here. Should I just wait for you Ian to commit the patch?
(Yeah, I think I don't need the ChangeLog entry.)
2015-08-24 Marek Polacek <pola...@redhat.com>
PR tree-optimization/67284
* go-gcc.cc (Gcc_backend::define_builtin): Add NORETURN_P default
argument. Set TREE_THIS_VOLATILE.
(Gcc_backend::Gcc_backend): Mark __builtin_trap as a noreturn call.
diff --git gcc/go/go-gcc.cc gcc/go/go-gcc.cc
index 6f274fc..aabcd98 100644
--- gcc/go/go-gcc.cc
+++ gcc/go/go-gcc.cc
@@ -498,7 +498,7 @@ class Gcc_backend : public Backend
private:
void
define_builtin(built_in_function bcode, const char* name, const char*
libname,
- tree fntype, bool const_p);
+ tree fntype, bool const_p, bool noreturn_p = false);
// A mapping of the GCC built-ins exposed to GCCGo.
std::map<std::string, Bfunction*> builtin_functions_;
@@ -675,7 +675,7 @@ Gcc_backend::Gcc_backend()
// cases.
this->define_builtin(BUILT_IN_TRAP, "__builtin_trap", NULL,
build_function_type(void_type_node, void_list_node),
- false);
+ false, true);
}
// Get an unnamed integer type.
@@ -3095,15 +3095,19 @@ Gcc_backend::write_global_definitions(
// LIBNAME is the name of the corresponding library function, and is
// NULL if there isn't one. FNTYPE is the type of the function.
// CONST_P is true if the function has the const attribute.
+// NORETURN_P is true if the function has the noreturn attribute.
void
Gcc_backend::define_builtin(built_in_function bcode, const char* name,
- const char* libname, tree fntype, bool const_p)
+ const char* libname, tree fntype, bool const_p,
+ bool noreturn_p)
{
tree decl = add_builtin_function(name, fntype, bcode, BUILT_IN_NORMAL,
libname, NULL_TREE);
if (const_p)
TREE_READONLY(decl) = 1;
+ if (noreturn_p)
+ TREE_THIS_VOLATILE(decl) = 1;
set_builtin_decl(bcode, decl, true);
this->builtin_functions_[name] = this->make_function(decl);
if (libname != NULL)
@@ -3112,6 +3116,8 @@ Gcc_backend::define_builtin(built_in_function bcode,
const char* name,
NULL, NULL_TREE);
if (const_p)
TREE_READONLY(decl) = 1;
+ if (noreturn_p)
+ TREE_THIS_VOLATILE(decl) = 1;
this->builtin_functions_[libname] = this->make_function(decl);
}
}
Marek
