In r480, I botched the change to make the comparisons that decide
whether an address falls within a function's range safe from overflow.
The original code said:
address >= function_base && address < function_base + function_size
which is fine unless the function abuts the end of the address space,
in which case the addition overflows and you get a false negative.
My change subtracted function_size from both sides of the latter
comparison, which is meaning-preserving in true math, and gets you:
address >= function_base && address - function_size < function_base
This not only reads strangely, but also still overflows if
function_size is greater than address. That's rare, but I've added a
case to the unit tests that checks it.
My intent had been to replace the addition which could overflow with a
subtraction that was known not to overflow, namely:
address >= function_base && address - function_base < function_size
This is equivalent to the original in true math, and because of the
first comparison, we know the subtraction won't underflow in MemAddr
math.
The patch includes similar fixes to the public symbol lookup code, and
to FindWindowsFrameInfo, which was the only other function affected by
r480.
a=jimblandy, r=mmentovai
git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@503 4c0a9323-5329-0410-9bdc-e9ce6186880e
At the moment, FillSourceLineInfo returns Windows DIA-based stack
walking data. In addition to being ugly, this makes it difficult to
provide access to DWARF CFI-based stack walking data in a symmetrical
way.
This patch changes FillSourceLineInfo to do the single job its name
suggests, and adds a second member function to
SourceLineResolverInterface to retrieve Windows DIA stack walking
information. A sibling member function will provide access to DWARF
CFI stack walking data.
a=jimblandy, r=mmentovai
git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@480 4c0a9323-5329-0410-9bdc-e9ce6186880e
Also, rename stack_frame_info.h to windows_frame_info.h.
If it seems odd to have functions like FillSourceLineInfo returning
Windows-specific data structures... well, it is! This patch just makes
it more obvious what's going on.
a=jimblandy, r=nealsid
git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@471 4c0a9323-5329-0410-9bdc-e9ce6186880e
Modern GNU compilers warn about the #inclusion of <ext/hash_map>; that
container is deprecated, and code should use <tr1/unordered_map>
instead. However, to stay within the boundaries of C++ '98, it's
probably fine just to use plain old std::map.
Breakpad uses hash_map in three cases:
o The DWARF reader's SectionMap type maps object file section names to
data. This map is consulted once per section kind per DWARF
compilation unit; it is not performance-critical.
o The Mac dump_syms tool uses it to map machine architectures to
section maps in Universal binaries. It's hard to imagine there
ever being more than two entries in such a map.
o The processor's BasicSourceLineResolver uses a hash_map to map file
numbers to file names. This is the map that will probably have the
most entries, but it's only accessed once per frame, after we've
found the frame's line entry.
a=jimblandy
r=nealsid
git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@393 4c0a9323-5329-0410-9bdc-e9ce6186880e
