For Hexagon we want to be able to call functions during debugging, however currently lldb only supports this when there is JIT support.
Although emulation using IR interpretation is an alternative, it is currently limited in that it can't make function calls.
In this patch we have extended the IR interpreter so that it can execute a function call on the target using register manipulation.
To do this we need to handle the Call IR instruction, passing arguments to a new thread plan and collecting any return values to pass back into the IR interpreter.
The new thread plan is needed to call an alternative ABI interface of "ABI::PerpareTrivialCall()", allowing more detailed information about arguments and return values.
Reviewers: jingham, spyffe
Subscribers: emaste, lldb-commits, ted, ADodds, deepak2427
Differential Revision: http://reviews.llvm.org/D9404
llvm-svn: 242137
The current strategy for host allocation is to choose a random
address and attempt to allocate there, eventually failing if the
allocation cannot be satisfied.
The C standard only guarantees that RAND_MAX >= 32767, so for
platforms that use a very small RAND_MAX allocations will fail
with very high probability. On such platforms (Windows is one),
you can reproduce this trivially by running lldb, typing "expr (3)"
and then hitting enter you see a failure. Failures generally
happen with a frequency of about 1 failure every 5 evaluations.
There is no good reason that allocations need to look like "real"
pointers, so this patch changes the allocation scheme to simply
jump straight to the end and grab a free chunk of memory.
Reviewed By: Sean Callanan
Differential Revision: http://reviews.llvm.org/D4300
llvm-svn: 212630
This change brings in lldb-gdbserver (llgs) specifically for Linux x86_64.
(More architectures coming soon).
Not every debugserver option is covered yet. Currently
the lldb-gdbserver command line can start unattached,
start attached to a pid (process-name attach not supported yet),
or accept lldb attaching and launching a process or connecting
by process id.
The history of this large change can be found here:
https://github.com/tfiala/lldb/tree/dev-tfiala-native-protocol-linux-x86_64
Until mid/late April, I was not sharing the work and continued
to rebase it off of head (developed via id tfiala@google.com). I switched over to
user todd.fiala@gmail.com in the middle, and once I went to github, I did
merges rather than rebasing so I could share with others.
llvm-svn: 212069
Previously, only the starting locations of the candidate interval
and the existing interval were compared. To correctly detect
range intersections, it is necessary to compare the entire range
of both intervals against each other.
Reviewed by: scallanan
Differential Revision: http://reviews.llvm.org/D4286
llvm-svn: 211726
(lldb) b puts
(lldb) expr -g -i0 -- (int)puts("hello")
First we will stop at the entry point of the expression before it runs, then we can step over a few times and hit the breakpoint in "puts", then we can continue and finishing stepping and fininsh the expression.
Main features:
- New ObjectFileJIT class that can be easily created for JIT functions
- debug info can now be enabled when parsing expressions
- source for any function that is run throught the JIT is now saved in LLDB process specific temp directory and cleaned up on exit
- "expr -g --" allows you to single step through your expression function with source code
<rdar://problem/16382881>
llvm-svn: 204682
bother checking if a region is safe to use. In
cases where regions need to be synthesized rather
than properly allocated, the memory reads required
to determine whether the area is used are
- insufficient, because intermediate locations
could be in use, and
- unsafe, because on some platforms reading from
memory can trigger events.
All this only makes a difference on platforms
where memory allocation in the target is impossible.
Behavior on platforms where it is possible should
stay the same.
<rdar://problem/14023970>
llvm-svn: 185046
live as long as they needed to. This led to
equality tests involving persistent variables
often failing or succeeding when they had no
business doing so.
To do this, I introduced the ability for a
memory allocation to "leak" - that is, to
persist in the process beyond the lifetime of
the expression. Hand-declared persistent
variables do this now.
<rdar://problem/13956311>
llvm-svn: 182528
regions that aren't actually allocated in the
process. This cache is used by the expression
parser if the underlying process doesn't support
memory allocation, to avoid needless repeated
searches for unused address ranges.
Also fixed a silly bug in IRMemoryMap where it
would continue searching even after it found a
valid region.
<rdar://problem/13866629>
llvm-svn: 182028
mostly related to management of the stack frame
for the interpreter.
- First, if the expression can be interpreted,
allocate the stack frame in the target process
(to make sure pointers are valid) but only
read/write to the copy in the host's memory.
- Second, keep the memory allocations for the
stack frame and the materialized struct as
member variables of ClangUserExpression. This
avoids memory allocations and deallocations
each time the expression runs.
<rdar://problem/13043685>
llvm-svn: 180664
and made attempts to allocate memory in the process
fall back to FindSpace and just allocate memory on
the host (but with real-looking pointers, hence
FindSpace) if the process doesn't allow allocation.
This allows expressions to run on processes that don't
support allocation, like core files.
This introduces an extremely rare potential problem:
If all of the following are true:
- The Process doesn't support allocation;
- the user writes an expression that refers to an
address that does not yet map to anything, or is
dynamically generated (e.g., the result of calling
a function); and
- the randomly-selected address for the static data
for that specific expression runs into the
address the user was expecting to work with;
then dereferencing the pointer later results
in the user seeing something unexpected. This is
unlikely but possible; as a future piece of work,
we should have processes be able to hint to the
expression parser where it can allocate temporary data
of this kind.
llvm-svn: 179827
expressions.
Previously, ClangUserExpression assumed that if
there was a constant result for an expression
then it could be determined during parsing. In
particular, the IRInterpreter ran while parser
state (in particular, ClangExpressionDeclMap)
was present. This approach is flawed, because
the IRInterpreter actually is capable of using
external variables, and hence the result might
be different each run. Until now, we papered
over this flaw by re-parsing the expression each
time we ran it.
I have rewritten the IRInterpreter to be
completely independent of the ClangExpressionDeclMap.
Instead of special-casing external variable lookup,
which ties the IRInterpreter closely to LLDB,
we now interpret the exact same IR that the JIT
would see. This IR assumes that materialization
has occurred; hence the recent implementation of the
Materializer, which does not require parser state
(in the form of ClangExpressionDeclMap) to be
present.
Materialization, interpretation, and dematerialization
are now all independent of parsing. This means that
in theory we can parse expressions once and run them
many times. I have three outstanding tasks before
shutting this down:
- First, I will ensure that all of this works with
core files. Core files have a Process but do not
allow allocating memory, which currently confuses
materialization.
- Second, I will make expression breakpoint
conditions remember their ClangUserExpression and
re-use it.
- Third, I will tear out all the redundant code
(for example, materialization logic in
ClangExpressionDeclMap) that is no longer used.
While implementing this fix, I also found a bug in
IRForTarget's handling of floating-point constants.
This should be fixed.
llvm-svn: 179801
IRMemoryMap rather than through its own memory
abstraction. This considerably simplifies the
code, and makes it possible to run the
IRInterpreter multiple times on an already-parsed
expression in the absence of a ClangExpressionDeclMap.
Changes include:
- ClangExpressionDeclMap's interface methods
for the IRInterpreter now take IRMemoryMap
arguments. They are not long for this world,
however, since the IRInterpreter will soon be
working with materialized variables.
- As mentioned above, removed the Memory class
from the IR interpreter altogether. It had a
few functions that remain useful, such as
keeping track of Values that have been placed
in memory, so I moved those into methods on
InterpreterStackFrame.
- Changed IRInterpreter to work with lldb::addr_t
rather than Memory::Region as its primary
currency.
- Fixed a bug in the IRMemoryMap where it did not
report correct address byte size and byte order
if no process was present, because it was using
Target::GetDefaultArchitecture() rather than
Target::GetArchitecture().
- Made IRMemoryMap methods clear the Errors they
receive before running. Having to do this by
hand is just annoying.
The testsuite seems happy with these changes, but
please let me know if you see problems (especially
in use cases without a process).
llvm-svn: 179675
Materializer for all expressions that need to
run in the target. This includes the following
changes:
- Removed a bunch of (de-)materialization code
from ClangExpressionDeclMap and assumed the
presence of a Materializer where we previously
had a fallback.
- Ensured that an IRMemoryMap is passed into
ClangExpressionDeclMap::Materialize().
- Fixed object ownership on LLVMContext; it is
now owned by the IRExecutionUnit, since the
Module and the ExecutionEngine both depend on
its existence.
- Fixed a few bugs in IRMemoryMap and the
Materializer that showed up during testing.
llvm-svn: 179649
- If an allocation is mirrored between the host
and the process, update the host's version
before returning a DataExtractor pointing to
it.
- If anyone attempts to access memory in a
process/target that does not have a corresponding
allocation, try accessing the memory directly
before erroring out.
llvm-svn: 179561
for variables in the new Materializer. This is
much easier now that the ValueObject API is solid.
I still have to implement reading bytes into a
ValueObject, but committing what I have so far.
This code is not yet used, so there will be fixes
when I switch the expression parser over to use the
new Materializer.
llvm-svn: 179416
from IRExecutionUnit into a superclass called
IRMemoryMap. IRMemoryMap handles all reading and
writing, ensuring that areas are kept track of and
memory is properly cached (and deleted).
Also fixed several cases where we would simply leak
binary data in the target process over time. Now
the expression objects explicitly own their
IRExecutionUnit and delete it when they go away. This
is why I had to modify ClangUserExpression,
ClangUtilityFunction, and ClangFunction.
As a side effect of this, I am removing the JIT
mutex for an IRMemoryMap. If it turns out that we
need this mutex, I'll add it in then, but right now
it's just adding complexity.
This is part of a more general project to make
expressions fully reusable. The next step is to
make materialization and dematerialization use
the IRMemoryMap API rather than writing and
reading directly from the process's memory.
This will allow the IR interpreter to use the
same data, but in the host's memory, without having
to use a different set of pointers.
llvm-svn: 178832
Ewan Crawford