py/emitnative: Access qstr values using indirection table qstr_table.

This changes the native emitter to access qstr values using the qstr
indirection table qstr_table, but only when generating native code that
will be saved to a .mpy file.  This makes the resulting native code fully
static, ie it does not require any fix-ups or rewriting when it is
imported.

The performance of native code is more or less unchanged.  Benchmark
results on PYBv1.0 (using --via-mpy and --emit native) are:

N=100 M=100          baseline -> this-commit     diff      diff% (error%)
bm_chaos.py            407.16 ->     411.85 :   +4.69 =  +1.152% (+/-0.01%)
bm_fannkuch.py         100.89 ->     101.20 :   +0.31 =  +0.307% (+/-0.01%)
bm_fft.py             3521.17 ->    3441.72 :  -79.45 =  -2.256% (+/-0.00%)
bm_float.py           6707.29 ->    6644.83 :  -62.46 =  -0.931% (+/-0.00%)
bm_hexiom.py            55.91 ->      55.41 :   -0.50 =  -0.894% (+/-0.00%)
bm_nqueens.py         5343.54 ->    5326.17 :  -17.37 =  -0.325% (+/-0.00%)
bm_pidigits.py         603.89 ->     632.79 :  +28.90 =  +4.786% (+/-0.33%)
core_qstr.py            64.18 ->      64.09 :   -0.09 =  -0.140% (+/-0.01%)
core_yield_from.py     313.61 ->     311.11 :   -2.50 =  -0.797% (+/-0.03%)
misc_aes.py            654.29 ->     659.75 :   +5.46 =  +0.834% (+/-0.02%)
misc_mandel.py        4205.10 ->    4272.08 :  +66.98 =  +1.593% (+/-0.01%)
misc_pystone.py       3077.79 ->    3128.39 :  +50.60 =  +1.644% (+/-0.01%)
misc_raytrace.py       388.45 ->     393.71 :   +5.26 =  +1.354% (+/-0.01%)
viper_call0.py         576.83 ->     566.76 :  -10.07 =  -1.746% (+/-0.05%)
viper_call1a.py        550.39 ->     540.12 :  -10.27 =  -1.866% (+/-0.11%)
viper_call1b.py        438.32 ->     432.09 :   -6.23 =  -1.421% (+/-0.11%)
viper_call1c.py        442.96 ->     436.11 :   -6.85 =  -1.546% (+/-0.08%)
viper_call2a.py        536.31 ->     527.37 :   -8.94 =  -1.667% (+/-0.04%)
viper_call2b.py        378.99 ->     377.50 :   -1.49 =  -0.393% (+/-0.08%)

Signed-off-by: Damien George <damien@micropython.org>

1 files changed, 1 insertions, 41 deletions

diff --git a/py/persistentcode.c b/py/persistentcode.c
index e23c775d1..d19a817aa 100644
--- a/py/persistentcode.c
+++ b/py/persistentcode.c
@@ -75,38 +75,6 @@ typedef struct _reloc_info_t {
     uint8_t *bss;
 } reloc_info_t;
 
-#if MICROPY_EMIT_THUMB
-STATIC void asm_thumb_rewrite_mov(uint8_t *pc, uint16_t val) {
-    // high part
-    *(uint16_t *)pc = (*(uint16_t *)pc & 0xfbf0) | (val >> 1 & 0x0400) | (val >> 12);
-    // low part
-    *(uint16_t *)(pc + 2) = (*(uint16_t *)(pc + 2) & 0x0f00) | (val << 4 & 0x7000) | (val & 0x00ff);
-
-}
-#endif
-
-STATIC void arch_link_qstr(uint8_t *pc, bool is_obj, qstr qst) {
-    mp_uint_t val = qst;
-    if (is_obj) {
-        val = (mp_uint_t)MP_OBJ_NEW_QSTR(qst);
-    }
-    #if MICROPY_EMIT_X86 || MICROPY_EMIT_X64 || MICROPY_EMIT_ARM || MICROPY_EMIT_XTENSA || MICROPY_EMIT_XTENSAWIN
-    pc[0] = val & 0xff;
-    pc[1] = (val >> 8) & 0xff;
-    pc[2] = (val >> 16) & 0xff;
-    pc[3] = (val >> 24) & 0xff;
-    #elif MICROPY_EMIT_THUMB
-    if (is_obj) {
-        // qstr object, movw and movt
-        asm_thumb_rewrite_mov(pc, val); // movw
-        asm_thumb_rewrite_mov(pc + 4, val >> 16); // movt
-    } else {
-        // qstr number, movw instruction
-        asm_thumb_rewrite_mov(pc, val); // movw
-    }
-    #endif
-}
-
 void mp_native_relocate(void *ri_in, uint8_t *text, uintptr_t reloc_text) {
     // Relocate native code
     reloc_info_t *ri = ri_in;
@@ -285,9 +253,6 @@ STATIC mp_raw_code_t *load_raw_code(mp_reader_t *reader) {
                 } else if ((off & 3) == 3) {
                     // Generic, aligned qstr-object link
                     *(mp_obj_t *)dest = MP_OBJ_NEW_QSTR(qst);
-                } else {
-                    // Architecture-specific link
-                    arch_link_qstr(dest, (off & 3) == 2, qst);
                 }
             }
         }
@@ -424,7 +389,6 @@ STATIC mp_raw_code_t *load_raw_code(mp_reader_t *reader) {
             #if MICROPY_PERSISTENT_CODE_SAVE
             n_children,
             prelude_offset,
-            0, NULL,
             #endif
             native_scope_flags, native_n_pos_args, native_type_sig
             );
@@ -605,11 +569,7 @@ STATIC void save_raw_code(mp_print_t *print, const mp_raw_code_t *rc) {
     #if MICROPY_EMIT_MACHINE_CODE
     if (rc->kind == MP_CODE_NATIVE_PY || rc->kind == MP_CODE_NATIVE_VIPER) {
         // Save qstr link table for native code
-        mp_print_uint(print, rc->n_qstr);
-        for (size_t i = 0; i < rc->n_qstr; ++i) {
-            mp_print_uint(print, rc->qstr_link[i].off);
-            save_qstr(print, rc->qstr_link[i].qst);
-        }
+        mp_print_uint(print, 0);
     }
 
     if (rc->kind == MP_CODE_NATIVE_PY) {