From cbec17f2cd2712772bc57f3530d6d16f8552e155 Mon Sep 17 00:00:00 2001 From: Damien George Date: Mon, 13 Aug 2018 23:34:47 +1000 Subject: [PATCH] py/compile: For dynamic compiler, widen literal 1 to get correct shift. Without this patch, on 64-bit architectures the "1 << (small_int_bits - 1)" is computed using only 32-bit values (since small_int_bits is a uint8_t) and so will overflow (and give the wrong result) if small_int_bits is larger than 32. --- py/compile.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/py/compile.c b/py/compile.c index 98c09b2107..df416b87f4 100644 --- a/py/compile.c +++ b/py/compile.c @@ -2685,7 +2685,7 @@ STATIC void compile_node(compiler_t *comp, mp_parse_node_t pn) { } else if (MP_PARSE_NODE_IS_SMALL_INT(pn)) { mp_int_t arg = MP_PARSE_NODE_LEAF_SMALL_INT(pn); #if MICROPY_DYNAMIC_COMPILER - mp_uint_t sign_mask = -(1 << (mp_dynamic_compiler.small_int_bits - 1)); + mp_uint_t sign_mask = -((mp_uint_t)1 << (mp_dynamic_compiler.small_int_bits - 1)); if ((arg & sign_mask) == 0 || (arg & sign_mask) == sign_mask) { // integer fits in target runtime's small-int EMIT_ARG(load_const_small_int, arg);