parser: add support for constant value substitution

Register symbolic constants as defined symbols when they are
defined.  When a constant symbol reference occurs after it's
been defined, the parsed token is modified to be a number type,
whose value is the value constant symbol.

One difference between a "normal" number token and a "constant"
number token is that the the string in a constant token contains
a copy of the symbolic name, whereas its a null pointer for a
"normal" number.

Signed-off-by: Alex Elder <elder@linaro.org>
Message-Id: <20211001232338.769309-35-elder@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

2 files changed, 38 insertions, 0 deletions

diff --git a/parser.c b/parser.c
index 8de8555..dd85ac5 100644
--- a/parser.c
+++ b/parser.c
@@ -42,6 +42,7 @@ enum token_id {
 	TOK_ID,
 	TOK_MESSAGE,
 	TOK_NUM,
+	TOK_VALUE,
 	TOK_PACKAGE,
 	TOK_STRUCT,
 	TOK_TYPE,
@@ -112,6 +113,7 @@ struct symbol {
 			/* TYPE_STRUCT also has a struct pointer */
 			struct qmi_struct *qmi_struct;
 		};
+		unsigned long long value;		/* TOK_VALUE */
 	};
 
 	struct list_head node;
@@ -200,6 +202,9 @@ static void symbol_add(const char *name, enum token_id token_id, ...)
 		if (sym->symbol_type == TYPE_STRUCT)
 			sym->qmi_struct = va_arg(ap, struct qmi_struct *);
 		break;
+	case TOK_VALUE:
+		sym->value = va_arg(ap, unsigned long long);
+		break;
 	default:
 		break;	/* Most tokens are standalone */
 	}
@@ -324,6 +329,11 @@ static struct token yylex()
 				token.num = sym->symbol_type;
 				token.qmi_struct = sym->qmi_struct;
 				break;
+			case TOK_VALUE:
+				/* Override token id; use numeric value */
+				token.id = TOK_NUM;
+				token.num = sym->value;
+				break;
 			default:
 				break;	/* Others just have id and string */
 			}
@@ -424,6 +434,8 @@ static void qmi_const_parse()
 	qc->value = num_tok.num;
 
 	list_add(&qmi_consts, &qc->node);
+
+	symbol_add(qc->name, TOK_VALUE, qc->value);
 }
 
 static void qmi_message_parse(enum message_type message_type)
diff --git a/tests/symbolic_values.qmi b/tests/symbolic_values.qmi
new file mode 100644
index 0000000..79821b9
--- /dev/null
+++ b/tests/symbolic_values.qmi
@@ -0,0 +1,26 @@
+package test;
+
+# Request identifiers
+const TEST_REQUEST_RESPONSE = 35;
+const TEST_INDICATION = 37;
+
+# Message field identifiers
+const QMI_RESULT = 2;
+
+struct qmi_result {
+	u16 result;
+	u16 error;
+};
+
+request test_request {
+	required u8 test_number = 0x12;
+} = TEST_REQUEST_RESPONSE;	# Value 35 gets substitued
+
+response test_response {
+	# Value 2 gets substitued for QMI_RESULT
+	required qmi_result r = QMI_RESULT;
+} = TEST_REQUEST_RESPONSE;
+
+indication test_indication {
+	optional u64 value = 0x99;
+} = TEST_INDICATION;		# Value 37 gets substitued