implement bitfield supportHEADmaster

1 files changed, 43 insertions, 2 deletions

diff --git a/dwarf-extract-struct.c b/dwarf-extract-struct.c
index 141bb83..ba6f838 100644
--- a/dwarf-extract-struct.c
+++ b/dwarf-extract-struct.c
@@ -266,6 +266,18 @@ static int dwarf_get_offset(Dwarf_Debug dbg, Dwarf_Die die,
 					 poffset, perr);
 }
 
+static int dwarf_get_bitfield(Dwarf_Debug dbg, Dwarf_Die die,
+		int *pbit_size, int *pbit_offset, Dwarf_Error *perr) {
+	int rc;
+	rc = dwarf_get_attribute_value(dbg, die, DW_AT_bit_size,
+				       pbit_size, perr);
+	if (rc) {
+		return rc;
+	}
+	return dwarf_get_attribute_value(dbg, die, DW_AT_bit_offset,
+					 pbit_offset, perr);
+}
+
 static int dwarf_get_size(Dwarf_Debug dbg, Dwarf_Die die,
 		int *psize, Dwarf_Error *perr) {
 	return dwarf_get_attribute_value(dbg, die, DW_AT_byte_size,
@@ -406,6 +418,7 @@ static void print_field(Dwarf_Debug dbg, Dwarf_Die die, const char *field_name,
 	char array_buf[128] = "";
 	char pointer_buf[128] = "";
 	int rc;
+	int bitfield_offset, bitfield_size = 0;
 
 	rc = dwarf_get_offset(dbg, die, &offset, &err);
 	if (rc == DW_DLV_NO_ENTRY) {
@@ -567,13 +580,41 @@ static void print_field(Dwarf_Debug dbg, Dwarf_Die die, const char *field_name,
 			}
 		}
 
-		if (type_tag == DW_TAG_structure_type) {
+		if (type_tag == DW_TAG_base_type &&
+		    dwarf_get_bitfield(dbg, die, &bitfield_size,
+				       &bitfield_offset, &err) == DW_DLV_OK) {
+			int type_size;
+
+			rc = dwarf_get_size(dbg, die, &type_size, &err);
+			if (rc != DW_DLV_OK) {
+				fprintf(stderr,
+					"Could not get size for type for %s: %s\n",
+					field_name, dwarf_errmsg(err));
+				exit(7);
+			}
+
+			/* One subtlety of bitfields is that the order
+			 * is reverse, e.g. the first bitfield will have
+			 * an offset of type size - bitfield size
+			 */
+			if (bitfield_size != type_size * 8 - bitfield_offset) {
+				snprintf(type_buf, 1024,
+					 "%s bitfield_padding%d:%d\n\t\t\t%s %s",
+					 type_name, padnum,
+					 type_size * 8 - bitfield_offset - bitfield_size,
+					 type_name, pointer_buf);
+			} else {
+				snprintf(type_buf, 1024, "%s %s", type_name,
+					 pointer_buf);
+			}
+			snprintf(array_buf, 128, ":%d", bitfield_size);
+		} else if (type_tag == DW_TAG_structure_type) {
 			snprintf(type_buf, 1024, "struct %s %s",
 				 type_name, pointer_buf);
 		} else if (type_tag == DW_TAG_base_type
 				|| type_tag == DW_TAG_typedef) {
 			snprintf(type_buf, 1024, "%s %s", type_name,
-				pointer_buf);
+				 pointer_buf);
 		} else if (type_tag == DW_TAG_pointer_type) {
 			snprintf(type_buf, 1024, "void %s", pointer_buf);
 		} else {