The Go frontend was assuming the usual required alignment for the
memequalNN functions (16 bits for int16, 32 for int32, etc.). However,
on m68k the required alignment of int32 is only 16 bits. Assuming the
memequalNN alignment caused the compiler to incorrectly decide that
int32 required a specially generated function rather than calling
memequal32. This then crashed if the type descriptor were generated
after type-specific functions had been written.
Bootstrapped and ran Go tests on x86_64-pc-linux-gnu. Committed to mainline.
This fixes GCC PR 80128.
Ian
Index: gcc/go/gofrontend/types.h
===================================================================
--- gcc/go/gofrontend/types.h (revision 245745)
+++ gcc/go/gofrontend/types.h (working copy)
@@ -993,6 +993,9 @@ class Type
const std::string& equal_name,
Function_type* equal_fntype);
+ // Return the alignment required by the memequalN function.
+ static int64_t memequal_align(Gogo*, int size);
+
// Export the type.
void
export_type(Export* exp) const
Index: gcc/go/gofrontend/types.cc
===================================================================
--- gcc/go/gofrontend/types.cc (revision 245745)
+++ gcc/go/gofrontend/types.cc (working copy)
@@ -1580,6 +1580,42 @@ Type::make_type_descriptor_ptr_type()
return ret;
}
+// Return the alignment required by the memequalN function. N is a
+// type size: 16, 32, 64, or 128. The memequalN functions are defined
+// in libgo/go/runtime/alg.go.
+
+int64_t
+Type::memequal_align(Gogo* gogo, int size)
+{
+ const char* tn;
+ switch (size)
+ {
+ case 16:
+ tn = "int16";
+ break;
+ case 32:
+ tn = "int32";
+ break;
+ case 64:
+ tn = "int64";
+ break;
+ case 128:
+ // The code uses [2]int64, which must have the same alignment as
+ // int64.
+ tn = "int64";
+ break;
+ default:
+ go_unreachable();
+ }
+
+ Type* t = Type::lookup_integer_type(tn);
+
+ int64_t ret;
+ if (!t->backend_type_align(gogo, &ret))
+ go_unreachable();
+ return ret;
+}
+
// Return whether this type needs specially built type functions.
// This returns true for types that are comparable and either can not
// use an identity comparison, or are a non-standard size.
@@ -1614,14 +1650,13 @@ Type::needs_specific_type_functions(Gogo
case 0:
case 1:
case 2:
- return align < 2;
+ return align < Type::memequal_align(gogo, 16);
case 4:
- return align < 4;
+ return align < Type::memequal_align(gogo, 32);
case 8:
- return align < 8;
+ return align < Type::memequal_align(gogo, 64);
case 16:
- // 8, not 16, because of how runtime.memequal128 is written.
- return align < 8;
+ return align < Type::memequal_align(gogo, 128);
default:
return true;
}
@@ -1713,7 +1748,7 @@ Type::type_functions(Gogo* gogo, Named_t
equal_fnname = "runtime.memequal8";
break;
case 2:
- if (align < 2)
+ if (align < Type::memequal_align(gogo, 16))
build_functions = true;
else
{
@@ -1722,7 +1757,7 @@ Type::type_functions(Gogo* gogo, Named_t
}
break;
case 4:
- if (align < 4)
+ if (align < Type::memequal_align(gogo, 32))
build_functions = true;
else
{
@@ -1731,7 +1766,7 @@ Type::type_functions(Gogo* gogo, Named_t
}
break;
case 8:
- if (align < 8)
+ if (align < Type::memequal_align(gogo, 64))
build_functions = true;
else
{
@@ -1740,8 +1775,7 @@ Type::type_functions(Gogo* gogo, Named_t
}
break;
case 16:
- // 8, not 16, because of how runtime.memequal128 is written.
- if (align < 8)
+ if (align < Type::memequal_align(gogo, 128))
build_functions = true;
else
{
