This recommits f665e80c02 which was reverted in 1cbd1b8f69 for breaking
TestFoundationDisassembly.py. The fix is to use --force in the test to avoid
bailing out on large functions.
I have also doubled the large function limit to 8000 bytes (~~ 2000 insns), as
the foundation library contains a lot of large-ish functions. The intent of this
feature is to prevent accidental disassembling of enormous (multi-megabyte)
"functions", not to get in people's way.
The original commit message follows:
If we have a binary without symbol information (and without
LC_FUNCTION_STARTS, if on a mac), then we have to resort to using
heuristics to determine the function boundaries. However, these don't
always work, and so we can easily end up thinking we have functions
which are several megabytes in size. Attempting to (accidentally)
disassemble these can take a very long time spam the terminal with
thousands of lines of disassembly.
This patch works around that problem by adding a sanity check to the
disassemble command. If we are about to disassemble a function which is
larger than a certain threshold, we will refuse to disassemble such a
function unless the user explicitly specifies the number of instructions
to disassemble, uses start/stop addresses for disassembly, or passes the
(new) --force argument.
The threshold is currently fairly aggressive (4000 bytes ~~ 1000
instructions). If needed, we can increase it, or even make it
configurable.
Differential Revision: https://reviews.llvm.org/D79789
Summary:
If we have a binary without symbol information (and without
LC_FUNCTION_STARTS, if on a mac), then we have to resort to using
heuristics to determine the function boundaries. However, these don't
always work, and so we can easily end up thinking we have functions
which are several megabytes in size. Attempting to (accidentally)
disassemble these can take a very long time spam the terminal with
thousands of lines of disassembly.
This patch works around that problem by adding a sanity check to the
disassemble command. If we are about to disassemble a function which is
larger than a certain threshold, we will refuse to disassemble such a
function unless the user explicitly specifies the number of instructions
to disassemble, uses start/stop addresses for disassembly, or passes the
(new) --force argument.
The threshold is currently fairly aggressive (4000 bytes ~~ 1000
instructions). If needed, we can increase it, or even make it
configurable.
Differential Revision: https://reviews.llvm.org/D79789
The function consisted of a complicated set of conditions to compute the
address ranges which are to be disassembled (depending on the mode
selected by command line switches). This patch creates a separate
function for each mode, so that DoExecute is only left with the task of
figuring out how to dump the relevant ranges.
This is NFC-ish, except for one change in the error message, which is
actually an improvement.
While we have some tests for this command already, they are very vague.
This is not surprising -- it's hard to make strict assertions about the
assembly if your input is a c++ source file. This means that the tests
can more-or-less only detect when the command breaks completely, and not
when there is a subtle change in meaning due to e.g. a code refactor --
which is something that I am getting ready to do.
This tests in this patch create binaries with well known data (via assembler
and yaml2obj). This means that we are able to make precise assertions
about the text that lldb is supposed to print. As some of the features
of this command are only available with a real process, I use a minidump
core file to create a sufficiently realistic process object.
Pavel Labath