tcg/tci: Add TCG_TARGET_CALL_{RET,ARG}_I128

Fill in the parameters for libffi for Int128.
Adjust the interpreter to allow for 16-byte return values.
Adjust tcg_out_call to record the return value length.

Call parameters are no longer all the same size, so we
cannot reuse the same call_slots array for every function.
Compute it each time now, but only fill in slots required
for the call we're about to make.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 19 insertions, 0 deletions

diff --git a/tcg/tcg.c b/tcg/tcg.c
index 098be83..865ed5e 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -570,6 +570,22 @@ static GHashTable *helper_table;
 #ifdef CONFIG_TCG_INTERPRETER
 static ffi_type *typecode_to_ffi(int argmask)
 {
+    /*
+     * libffi does not support __int128_t, so we have forced Int128
+     * to use the structure definition instead of the builtin type.
+     */
+    static ffi_type *ffi_type_i128_elements[3] = {
+        &ffi_type_uint64,
+        &ffi_type_uint64,
+        NULL
+    };
+    static ffi_type ffi_type_i128 = {
+        .size = 16,
+        .alignment = __alignof__(Int128),
+        .type = FFI_TYPE_STRUCT,
+        .elements = ffi_type_i128_elements,
+    };
+
     switch (argmask) {
     case dh_typecode_void:
         return &ffi_type_void;
@@ -583,6 +599,8 @@ static ffi_type *typecode_to_ffi(int argmask)
         return &ffi_type_sint64;
     case dh_typecode_ptr:
         return &ffi_type_pointer;
+    case dh_typecode_i128:
+        return &ffi_type_i128;
     }
     g_assert_not_reached();
 }
@@ -613,6 +631,7 @@ static void init_ffi_layouts(void)
         /* Ignoring the return type, find the last non-zero field. */
         nargs = 32 - clz32(typemask >> 3);
         nargs = DIV_ROUND_UP(nargs, 3);
+        assert(nargs <= MAX_CALL_IARGS);
 
         ca = g_malloc0(sizeof(*ca) + nargs * sizeof(ffi_type *));
         ca->cif.rtype = typecode_to_ffi(typemask & 7);