py, compiler: Remove emit_pass1 code, using emit_bc to do its job.

First pass for the compiler is computing the scope (eg if an identifier
is local or not) and originally had an entire table of methods dedicated
to this, most of which did nothing.  With changes from previous commit,
this set of methods can be removed and the methods from the bytecode
emitter used instead, with very little modification -- this is what is
done in this commit.

This factoring has little to no impact on the speed of the compiler
(tested by compiling 3763 Python scripts and timing it).

This factoring reduces code size by about 270-300 bytes on Thumb2 archs,
and 400 bytes on x86.

1 files changed, 28 insertions, 12 deletions

diff --git a/py/compile.c b/py/compile.c
index 4b78b7f37..a41851c3a 100644
--- a/py/compile.c
+++ b/py/compile.c
@@ -3647,9 +3647,21 @@ mp_obj_t mp_compile(mp_parse_node_t pn, qstr source_file, uint emit_opt, bool is
     module_scope->pn = fold_constants(comp, module_scope->pn, &consts);
     mp_map_deinit(&consts);
 
+    // create standard emitter; it's used at least for MP_PASS_SCOPE
+    #if MICROPY_EMIT_CPYTHON
+    emit_t *emit_cpython = emit_cpython_new();
+    #else
+    emit_t *emit_bc = emit_bc_new();
+    #endif
+
     // compile pass 1
-    comp->emit = NULL;
-    comp->emit_method_table = &emit_pass1_method_table;
+    #if MICROPY_EMIT_CPYTHON
+    comp->emit = emit_cpython;
+    comp->emit_method_table = &emit_cpython_method_table;
+    #else
+    comp->emit = emit_bc;
+    comp->emit_method_table = &emit_bc_method_table;
+    #endif
     #if MICROPY_EMIT_INLINE_THUMB
     comp->emit_inline_asm = NULL;
     comp->emit_inline_asm_method_table = NULL;
@@ -3676,9 +3688,15 @@ mp_obj_t mp_compile(mp_parse_node_t pn, qstr source_file, uint emit_opt, bool is
         scope_compute_things(s);
     }
 
+    // set max number of labels now that it's calculated
+    #if MICROPY_EMIT_CPYTHON
+    emit_cpython_set_max_num_labels(emit_cpython, max_num_labels);
+    #else
+    emit_bc_set_max_num_labels(emit_bc, max_num_labels);
+    #endif
+
     // compile pass 2 and 3
 #if !MICROPY_EMIT_CPYTHON
-    emit_t *emit_bc = NULL;
 #if MICROPY_EMIT_NATIVE
     emit_t *emit_native = NULL;
 #endif
@@ -3711,7 +3729,7 @@ mp_obj_t mp_compile(mp_parse_node_t pn, qstr source_file, uint emit_opt, bool is
             // choose the emit type
 
 #if MICROPY_EMIT_CPYTHON
-            comp->emit = emit_cpython_new(max_num_labels);
+            comp->emit = emit_cpython;
             comp->emit_method_table = &emit_cpython_method_table;
 #else
             switch (s->emit_options) {
@@ -3746,9 +3764,6 @@ mp_obj_t mp_compile(mp_parse_node_t pn, qstr source_file, uint emit_opt, bool is
 #endif // MICROPY_EMIT_NATIVE
 
                 default:
-                    if (emit_bc == NULL) {
-                        emit_bc = emit_bc_new(max_num_labels);
-                    }
                     comp->emit = emit_bc;
                     comp->emit_method_table = &emit_bc_method_table;
                     break;
@@ -3771,10 +3786,11 @@ mp_obj_t mp_compile(mp_parse_node_t pn, qstr source_file, uint emit_opt, bool is
     }
 
     // free the emitters
-#if !MICROPY_EMIT_CPYTHON
-    if (emit_bc != NULL) {
-        emit_bc_free(emit_bc);
-    }
+
+#if MICROPY_EMIT_CPYTHON
+    emit_cpython_free(emit_cpython);
+#else
+    emit_bc_free(emit_bc);
 #if MICROPY_EMIT_NATIVE
     if (emit_native != NULL) {
 #if MICROPY_EMIT_X64
@@ -3793,7 +3809,7 @@ mp_obj_t mp_compile(mp_parse_node_t pn, qstr source_file, uint emit_opt, bool is
         emit_inline_thumb_free(emit_inline_thumb);
     }
 #endif
-#endif // !MICROPY_EMIT_CPYTHON
+#endif // MICROPY_EMIT_CPYTHON
 
     // free the parse tree
     mp_parse_node_free(module_scope->pn);