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b095682a89
line with the DWARF3 spec and also with binutils/readelf.c: - Update some comments - Get rid of kludge_then_addDiCfSI; apparently no longer needed - Pass the SegInfo's text_bias around in the AddressDecodingInfo, so that ... - read_encoded_Addr can set 'base' to the text_bias when handling DW_EH_PE_absptr. This is the central change of this commit and appears (to me) to be what DWARF3 requires. (The spec is less than clear ..) - don't use read_encoded_Addr to read the FDE arange field since read_encoded_Addr's adding-on of a 'base' value is meaningless here - the arange is not an address, but a value saying how many bytes the FDE covers. Instead just read a little-endian value of the right size. This is in accordance with DWARF3 and with readelf.c. Add new function read_le_encoded_literal to make this possible. I believe this is all correct, and it's certainly much better than it was. But given that the DWARF3 spec isn't as formal as it should be, it's hard to be sure. git-svn-id: svn://svn.valgrind.org/valgrind/trunk@6611
On 4 Apr 06, the debuginfo reader (m_debuginfo) was majorly cleaned up
and restructured. It has been a bit of a tangle for a while. The new
structure looks like this:
debuginfo.c
readelf.c
readdwarf.c readstabs.c
storage.c
Each .c can only call those below it on the page.
storage.c contains the SegInfo structure and stuff for
maintaining/searching arrays of symbols, line-numbers, and Dwarf CF
info records.
readdwarf.c and readstabs.c parse the relevant kind of info and
call storage.c to store the results.
readelf.c reads ELF format, hands syms directly to storage.c,
then delegates to readdwarf.c/readstabs.c for debug info. All
straightforward.
debuginfo.c is the top-level file, and is quite small.
There are 3 goals to this:
(1) Generally tidy up something which needs tidying up
(2) Introduce more modularity, so as to make it easier to add
readers for other formats, if needed
(3) Simplify the stabs reader.
Rationale for (1) and (2) are obvious.
Re (3), the stabs reader has for a good year contained a sophisticated
and impressive parser for stabs strings, with the aim of recording in
detail the types of variables (I think) (Jeremy's work). Unfortunately
that has caused various segfaults reading stabs info in the past few months
(#77869, #117936, #119914, #120345 and another to do with deeply nested
template types).
The worst thing is that it is the stabs type reader that is crashing,
not the stabs line-number reader, but the type info is only used by
Helgrind, which is looking pretty dead at the moment. So I have lifed
out the type-reader code and put it in UNUSED_STABS.txt for safe
storage, just leaving the line-number reader in place.
If Helgrind ever does come back to life we will need to reinstate the
type storage/reader stuff but with DWARF as its primary target.
Placing the existing stabs type-reader in hibernation improves
stability whilst retaining the development effort/expertise that went
into it for possible future reinstatement.