Example #1
0
	u32					xbinary_reader::read(s8  & b)
	{
		if (_can_read(len_, cursor_, sizeof(b)))
		{
			xbyte const* ptr = buffer_ + cursor_;
			cursor_ += sizeof(b);
			b = read_s8(ptr);
			return sizeof(b);
		}
		return 0;
	}
Example #2
0
bool
db_dwarf_line_at_pc(const char *linetab, size_t linetabsize, uintptr_t pc,
    const char **outdirname, const char **outbasename, int *outline)
{
	struct dwbuf table = { .buf = linetab, .len = linetabsize };

	/*
	 * For simplicity, we simply brute force search through the entire
	 * line table each time.
	 */
	uint32_t unitsize;
	struct dwbuf unit;
next:
	/* Line tables are a sequence of compilation unit entries. */
	if (!read_u32(&table, &unitsize) || unitsize >= 0xfffffff0 ||
	    !read_buf(&table, &unit, unitsize))
		return (false);

	uint16_t version;
	uint32_t header_size;
	if (!read_u16(&unit, &version) || version > 2 ||
	    !read_u32(&unit, &header_size))
		goto next;

	struct dwbuf headerstart = unit;
	uint8_t min_insn_length, default_is_stmt, line_range, opcode_base;
	int8_t line_base;
	if (!read_u8(&unit, &min_insn_length) ||
	    !read_u8(&unit, &default_is_stmt) ||
	    !read_s8(&unit, &line_base) ||
	    !read_u8(&unit, &line_range) ||
	    !read_u8(&unit, &opcode_base))
		goto next;

	/*
	 * Directory and file names are next in the header, but for now we
	 * skip directly to the line number program.
	 */
	struct dwbuf names = unit;
	unit = headerstart;
	if (!skip_bytes(&unit, header_size))
		return (false);

	/* VM registers. */
	uint64_t address = 0, file = 1, line = 1, column = 0;
	uint8_t is_stmt = default_is_stmt;
	bool basic_block = false, end_sequence = false;
	bool prologue_end = false, epilogue_begin = false;

	/* Last line table entry emitted, if any. */
	bool have_last = false;
	uint64_t last_line = 0, last_file = 0;

	/* Time to run the line program. */
	uint8_t opcode;
	while (read_u8(&unit, &opcode)) {
		bool emit = false, reset_basic_block = false;

		if (opcode >= opcode_base) {
			/* "Special" opcodes. */
			uint8_t diff = opcode - opcode_base;
			address += diff / line_range;
			line += line_base + diff % line_range;
			emit = true;
		} else if (opcode == 0) {
			/* "Extended" opcodes. */
			uint64_t extsize;
			struct dwbuf extra;
			if (!read_uleb128(&unit, &extsize) ||
			    !read_buf(&unit, &extra, extsize) ||
			    !read_u8(&extra, &opcode))
				goto next;
			switch (opcode) {
			case DW_LNE_end_sequence:
				emit = true;
				end_sequence = true;
				break;
			case DW_LNE_set_address:
				switch (extra.len) {
				case 4: {
					uint32_t address32;
					if (!read_u32(&extra, &address32))
						goto next;
					address = address32;
					break;
				}
				case 8:
					if (!read_u64(&extra, &address))
						goto next;
					break;
				default:
					DWARN("unexpected address length: %zu",
					    extra.len);
					goto next;
				}
				break;
			case DW_LNE_define_file:
				/* XXX: hope this isn't needed */
			default:
				DWARN("unknown extended opcode: %d", opcode);
				goto next;
			}
		} else {
			/* "Standard" opcodes. */
			switch (opcode) {
			case DW_LNS_copy:
				emit = true;
				reset_basic_block = true;
				break;
			case DW_LNS_advance_pc: {
				uint64_t delta;
				if (!read_uleb128(&unit, &delta))
					goto next;
				address += delta * min_insn_length;
				break;
			}
			case DW_LNS_advance_line: {
				int64_t delta;
				if (!read_sleb128(&unit, &delta))
					goto next;
				line += delta;
				break;
			}
			case DW_LNS_set_file:
				if (!read_uleb128(&unit, &file))
					goto next;
				break;
			case DW_LNS_set_column:
				if (!read_uleb128(&unit, &column))
					goto next;
				break;
			case DW_LNS_negate_stmt:
				is_stmt = !is_stmt;
				break;
			case DW_LNS_set_basic_block:
				basic_block = true;
				break;
			case DW_LNS_const_add_pc:
				address += (255 - opcode_base) / line_range;
				break;
			case DW_LNS_set_prologue_end:
				prologue_end = true;
				break;
			case DW_LNS_set_epilogue_begin:
				epilogue_begin = true;
				break;
			default:
				DWARN("unknown standard opcode: %d", opcode);
				goto next;
			}
		}

		if (emit) {
			if (address > pc) {
				/* Found an entry after our target PC. */
				if (!have_last) {
					/* Give up on this program. */
					break;
				}
				/* Return the last entry. */
				*outline = last_line;
				return (read_filename(&names, outdirname,
				    outbasename, opcode_base, file));
			}

			last_file = file;
			last_line = line;
			have_last = true;
		}

		if (reset_basic_block)
			basic_block = false;
	}

	goto next;
}