py/emitnative: Let emitters know the compiled entity's name.

This commit introduces an optional feature to provide to native emitters
the fully qualified name of the entity they are compiling.

This is achieved by altering the generic ASM API to provide a third
argument to the entry function, containing the name of the entity being
compiled.  Currently only the debug emitter uses this feature, as it is
not really useful for other emitters for the time being; in fact the
macros in question just strip the name away.

Signed-off-by: Alessandro Gatti <a.gatti@frob.it>

py/emitnative.c

@@ -419,6 +419,30 @@ static void emit_native_start_pass(emit_t *emit, pass_kind_t pass, scope_t *scop
         emit->stack_info[i].vtype = VTYPE_UNBOUND;
     }
 
+    char *qualified_name = NULL;
+
+    #if N_DEBUG
+    scope_t *current_scope = scope;
+    vstr_t *qualified_name_vstr = vstr_new(qstr_len(current_scope->simple_name));
+    size_t fragment_length = 0;
+    const byte *fragment_pointer;
+    for (;;) {
+        fragment_pointer = qstr_data(current_scope->simple_name, &fragment_length);
+        vstr_hint_size(qualified_name_vstr, fragment_length);
+        memmove(qualified_name_vstr->buf + fragment_length, qualified_name_vstr->buf, qualified_name_vstr->len);
+        memcpy(qualified_name_vstr->buf, fragment_pointer, fragment_length);
+        qualified_name_vstr->len += fragment_length;
+        if (current_scope->parent == NULL || current_scope->parent->simple_name == MP_QSTR__lt_module_gt_) {
+            break;
+        }
+        vstr_ins_char(qualified_name_vstr, 0, '.');
+        current_scope = current_scope->parent;
+    }
+    qualified_name = vstr_null_terminated_str(qualified_name_vstr);
+    #else
+    (void)qualified_name;
+    #endif
+
     mp_asm_base_start_pass(&emit->as->base, pass == MP_PASS_EMIT ? MP_ASM_PASS_EMIT : MP_ASM_PASS_COMPUTE);
 
     // generate code for entry to function
@@ -465,7 +489,7 @@ static void emit_native_start_pass(emit_t *emit, pass_kind_t pass, scope_t *scop
         }
 
         // Entry to function
-        ASM_ENTRY(emit->as, emit->stack_start + emit->n_state - num_locals_in_regs);
+        ASM_ENTRY(emit->as, emit->stack_start + emit->n_state - num_locals_in_regs, qualified_name);
 
         #if N_X86
         asm_x86_mov_arg_to_r32(emit->as, 0, REG_PARENT_ARG_1);
@@ -536,7 +560,7 @@ static void emit_native_start_pass(emit_t *emit, pass_kind_t pass, scope_t *scop
 
         if (emit->scope->scope_flags & MP_SCOPE_FLAG_GENERATOR) {
             mp_asm_base_data(&emit->as->base, ASM_WORD_SIZE, (uintptr_t)emit->start_offset);
-            ASM_ENTRY(emit->as, emit->code_state_start);
+            ASM_ENTRY(emit->as, emit->code_state_start, qualified_name);
 
             // Reset the state size for the state pointed to by REG_GENERATOR_STATE
             emit->code_state_start = 0;
@@ -568,7 +592,7 @@ static void emit_native_start_pass(emit_t *emit, pass_kind_t pass, scope_t *scop
             emit->stack_start = emit->code_state_start + SIZEOF_CODE_STATE;
 
             // Allocate space on C-stack for code_state structure, which includes state
-            ASM_ENTRY(emit->as, emit->stack_start + emit->n_state);
+            ASM_ENTRY(emit->as, emit->stack_start + emit->n_state, qualified_name);
 
             // Prepare incoming arguments for call to mp_setup_code_state
 
@@ -634,6 +658,10 @@ static void emit_native_start_pass(emit_t *emit, pass_kind_t pass, scope_t *scop
             }
         }
     }
+
+    #if N_DEBUG
+    vstr_free(qualified_name_vstr);
+    #endif
 }
 
 static inline void emit_native_write_code_info_byte(emit_t *emit, byte val) {