blocks of memory, and if the final bytes of that block look like a long
x86 instruction, it can cause the llvm disassembler to read past the end
of the buffer. Use the maximum allowed instruction length that we pass
to the llvm disassembler as a way to limit this to the size of the buffer.
An example of how to trigger this is when lldb does a function call, it
puts a breakpoint on the beginning of main() and uses that as the return
address from the function call. When we stop at that location, lldb may
try to find the first frame up the stack. Because this is on the first
instruction of a function, it will get the word-size value at the stack
pointer and assume that this was the caller's pc value. But this is random
stack memory and could point to anything - an object in memory, something
in the data section, whatever. And if we have a symbol for that thing,
we'll try to disassemble it.
This was leading to infrequent crashes in customer scenarios; figured out
what was happening with address sanitizer.
<rdar://problem/30463256>
llvm-svn: 307454
Summary:
The instruction pattern:
and $-16, %esp
sub $imm, %esp
...
lea imm(%ebp), %esp
appears when the compiler is realigning the stack (for example in
main(), or almost everywhere with -mstackrealign switch). The "and"
instruction is very difficult to model, but that's not necessary, as
these frames are always %ebp-based (the compiler also needs a way to
restore the original %esp). Therefore the plans we were generating for
these function were almost correct already. The only place we were doing
it wrong were the last instructions of the epilogue (usually just
"ret"), where we had to revert to %esp-based unwinding, as the %ebp had
been popped already.
This was wrong because our "distance of esp from cfa" counter had picked
up the "sub" instruction (and incremented the counter) but it had not
seen that the register was reset by the "lea" instruction.
This patch fixes that shortcoming, and adds a test for handling
functions like this.
I have not been able to tickle the compiler into producing a 64-bit
function with this pattern, but I don't see a reason why it couldn't
produce it, if it chose to, so I add a x86_64 test as well.
Reviewers: jasonmolenda, tberghammer
Subscribers: lldb-commits
Differential Revision: https://reviews.llvm.org/D34750
llvm-svn: 306666
This renames the LLDB error class to Status, as discussed
on the lldb-dev mailing list.
A change of this magnitude cannot easily be done without
find and replace, but that has potential to catch unwanted
occurrences of common strings such as "Error". Every effort
was made to find all the obvious things such as the word "Error"
appearing in a string, etc, but it's possible there are still
some lingering occurences left around. Hopefully nothing too
serious.
llvm-svn: 302872
Add missing linkage of the lldbPluginUnwindAssemblyX86 to LLVMMCDisasm
library. This fixes the following build failure when linking against
shared libraries:
lib64/liblldbPluginUnwindAssemblyX86.a(x86AssemblyInspectionEngine.cpp.o):x86AssemblyInspectionEngine.cpp:function lldb_private::x86AssemblyInspectionEngine::instruction_length(unsigned char*, int&): error: undefined reference to 'LLVMDisasmInstruction'
lib64/liblldbPluginUnwindAssemblyX86.a(x86AssemblyInspectionEngine.cpp.o):x86AssemblyInspectionEngine.cpp:function lldb_private::x86AssemblyInspectionEngine::~x86AssemblyInspectionEngine(): error: undefined reference to 'LLVMDisasmDispose'
lib64/liblldbPluginUnwindAssemblyX86.a(x86AssemblyInspectionEngine.cpp.o):x86AssemblyInspectionEngine.cpp:function lldb_private::x86AssemblyInspectionEngine::x86AssemblyInspectionEngine(lldb_private::ArchSpec const&): error: undefined reference to 'LLVMCreateDisasm'
Differential Revision: https://reviews.llvm.org/D31369
llvm-svn: 298777
In an effort to move the various DataBuffer / DataExtractor
classes from Core -> Utility, we have to separate the low-level
functionality from the higher level functionality. Only a
few functions required anything other than reading/writing
raw bytes, so those functions are separated out into a
more appropriate area. Specifically, Dump() and DumpHexBytes()
are moved into free functions in Core/DumpDataExtractor.cpp,
and GetGNUEHPointer is moved into a static function in the
only file that it's referenced from.
Differential Revision: https://reviews.llvm.org/D30560
llvm-svn: 296910
All references to Host and Core have been removed, so this
class can now safely be lowered into Utility.
Differential Revision: https://reviews.llvm.org/D30559
llvm-svn: 296909
With this patch, the only dependency left is from Utility
to Host. After this is broken, Utility will finally be
standalone.
Differential Revision: https://reviews.llvm.org/D29909
llvm-svn: 295088
This moves the following classes from Core -> Utility.
ConstString
Error
RegularExpression
Stream
StreamString
The goal here is to get lldbUtility into a state where it has
no dependendencies except on itself and LLVM, so it can be the
starting point at which to start untangling LLDB's dependencies.
These are all low level and very widely used classes, and
previously lldbUtility had dependencies up to lldbCore in order
to use these classes. So moving then down to lldbUtility makes
sense from both the short term and long term perspective in
solving this problem.
Differential Revision: https://reviews.llvm.org/D29427
llvm-svn: 293941
Also found/fixed one bug identified by this warning in
RenderScriptx86ABIFixups.cpp where a string literal was being used in an
effort to provide a name for an instruction/register, but was instead
being passed as the bool 'isVolatile' parameter.
llvm-svn: 291198
This is a large API change that removes the two functions from
StreamString that return a std::string& and a const std::string&,
and instead provide one function which returns a StringRef.
Direct access to the underlying buffer violates the concept of
a "stream" which is intended to provide forward only access,
and makes porting to llvm::raw_ostream more difficult in the
future.
Differential Revision: https://reviews.llvm.org/D26698
llvm-svn: 287152
plan generator.
Fix a small bug in EmulateInstructionARM64::GetFramePointerRegister
which was returning the stack pointer reg instead of fp, prevented
the unwinder from recognizing the switch to using the fp in a
function. (<rdar://problem/28663117>)
Add a new eContextRestoreStackPointer context hint so that the arm64
emulator can flag when the frame pointer value is copied back in to
the stack pointer and that should be used to compute the canonical
frame address again in an epilogue sequence. (<rdar://problem/28704862>)
Small changes to UnwindAssemblyInstEmulation to have a method we can
call without a live process/thread/etc for unit tests.
<rdar://problem/28663117>
<rdar://problem/28704862>
<rdar://problem/28509178>
llvm-svn: 283847
unittests. If I have time, I'd like to see if I can write some
tests of the eh_frame augmentation which is a wholly separate code
path (it seems like maybe it should be rolled into the main instruction
scanning codepath, to be honest, and operate on the generated
UnwindPlan instead of bothering with raw instructions at all).
Outside the eh_frame augmentation, I'm comfortable that this unwind
generator is being tested well now.
llvm-svn: 283186
'push 0x20(%esp)' which clang can generate when emitting
-fomit-frame-pointer code for 32-bit.
Add a unit test program which includes this instruction.
Also fix a bug in the refactoring/rewrite of the x86 assembly
instruction profiler where I'd hard coded it as a 64-bit disassembler
instead of using the ArchSpec to pick a 32-bit or 64-bit disassembler
from llvm. When the disassembler would hit an instruction
that is invalid in 64-bit mode, it would stop disassembling the function.
This likely led to the TestSBData testsuite failure on linux with 32-bit
i386 and gcc-4.9; I'll test that in a bit.
The newly added unit test program is 32-bit i386 code and it includes
an instruction which is invalid in 64-bit mode so it will catch this.
<rdar://problem/28557876>
llvm-svn: 282991
a linux bot test failure. That one is fixed; hopefully there won't
be any others turned up this time.
The eh_frame augmentation code wasn't working right after the
reorg/rewrite of the classes. It works correctly now for the one
test that was failing - but we'll see what the test bots come up
with.
<rdar://problem/28509178>
llvm-svn: 282659
A testbot found a regression introduced in the testsuite with
the changes in r282565 on Ubuntu (TestStepNoDebug.ReturnValueTestCase).
I'll get this set up on an ubuntu box and figure out what is happening
there -- likely a problem with the eh_frame augmentation, which isn't
used on macosx.
llvm-svn: 282566
x86AssemblyInspectionEngine and the current UnwindAssembly_x86 to
allow for the core engine to be exercised by unit tests.
The UnwindAssembly_x86 class will have access to Targets, Processes,
Threads, RegisterContexts -- it will be working in the full lldb
environment.
x86AssemblyInspectionEngine is layered away from all of that, it is
given some register definitions and a bag of bytes to profile.
I wrote an initial unittest for a do-nothing simple x86_64/i386
function to start with. I'll be adding more.
The x86 assembly unwinder was added to lldb early in its bringup;
I made some modernization changes as I was refactoring the code
to make it more consistent with how we write lldb today.
I also added RegisterContextMinidump_x86_64.cpp to the xcode project
file so I can run the unittests from that.
The testsuite passes with this change, but there was quite a bit of
code change by the refactoring and it's possible there are some
issues. I'll be testing this more in the coming days, but it looks
like it is behaving correctly as far as I can tell with automated
testing.
<rdar://problem/28509178>
llvm-svn: 282565
*** to conform to clang-format’s LLVM style. This kind of mass change has
*** two obvious implications:
Firstly, merging this particular commit into a downstream fork may be a huge
effort. Alternatively, it may be worth merging all changes up to this commit,
performing the same reformatting operation locally, and then discarding the
merge for this particular commit. The commands used to accomplish this
reformatting were as follows (with current working directory as the root of
the repository):
find . \( -iname "*.c" -or -iname "*.cpp" -or -iname "*.h" -or -iname "*.mm" \) -exec clang-format -i {} +
find . -iname "*.py" -exec autopep8 --in-place --aggressive --aggressive {} + ;
The version of clang-format used was 3.9.0, and autopep8 was 1.2.4.
Secondly, “blame” style tools will generally point to this commit instead of
a meaningful prior commit. There are alternatives available that will attempt
to look through this change and find the appropriate prior commit. YMMV.
llvm-svn: 280751
This change is improving the instruction emulation based unwinding to
handle when the frame pointer is adjusted (increment/decrement) after
it has been initialized. The situation can occur in the prologue of
some function where FP is adjusted before it is copied back to SP.
Example code (thumb, generated by gcc 4.8):
< +0>: push {r4, r7, lr}
< +2>: sub sp, #0x14
< +4>: add r7, sp, #0x0
...
<+50>: adds r7, #0x14 ; The CL fixes the handling of this instruction
<+52>: mov sp, r7 ; Previously unwinding from here was broken
<+54>: pop {r4, r7, pc}
Differential revision: http://reviews.llvm.org/D17295
llvm-svn: 261318
The IT instruction can specify condition code for up to 4 consecutive
instruction and it is used quite often by clang in epilogues causing
an issue when trying to unwind from locations covered by the IT
instruction and for locatins inmediately after the IT instruction.
Changes made to fix it:
* Introduce the concept of conditional instruction block what is a list
of consecutive instructions with the same condition. We update the
unwind information during the conditional instruction block and when
we reach the end of it (first instruction with a differemt condition)
then we restore the unwind information we had before the condition.
* Fix a bug in the ARM instruction emulator where neither PC nor the
ITSTATE was advanced when we reached an instruction what we can't
decode.
After the change we have no regression on android-arm running the
regular test suit and TestStandardUnwind also passes when running it
with clang as the compiler (previously it failed on an IT instruction).
Differential revision: http://reviews.llvm.org/D16814
llvm-svn: 260368
Summary:
This doesn't exist in other LLVM projects any longer and doesn't
do anything.
Reviewers: chaoren, labath
Subscribers: emaste, tberghammer, lldb-commits, danalbert
Differential Revision: http://reviews.llvm.org/D12586
llvm-svn: 246749
Change the way EmulateInstruction::eContextPopRegisterOffStack handled
in UnwindAssemblyInstEmulation::WriteRegister to accomodate for
additional cases when eContextPopRegisterOffStack (pop PC/FLAGS).
llvm-svn: 245690
On ARM there is no difference petween a pop and a load instruction so
a register can be loaded multiple times during the function. Add check
to threat the load as a restore only if it do the restore from the
same location where the register was saved.
Differential revision: http://reviews.llvm.org/D11947
llvm-svn: 245546
Don't chane the CFI information when a conditional instruction
is emulated (eg.: popeq {r0, pc}) because the CFI for the next
instruction should be the same as the CFI for the current instruction.
Differential revision: http://reviews.llvm.org/D11258
llvm-svn: 242519
Summary: This aligns the library names used by the Makefile build to be the same as those create by the CMake build to make switching between the two easier. The only major difficulty was lldbHost which was one library in the CMake system and several in the Makefile system. Most of the other changes are trivial renames.
Reviewers: labath
Subscribers: emaste, tberghammer, lldb-commits
Differential Revision: http://reviews.llvm.org/D11154
llvm-svn: 242196
These instructions confusing the unwind code because in case of a
push it assumes that the original valu of a register is pushed to
the stack what is not neccessarily true in case of SP. The same is
true for the pop (in the opposite way).
Differential revision: http://reviews.llvm.org/D10806
llvm-svn: 241051
The emulation of the branches are required by the new stack
unwinding logic to reinstantiate the prologue at the right place.
Differential revision: http://reviews.llvm.org/D10702
llvm-svn: 240769
* Add and fix the emulation of several instruction.
* Disable frame pointer usage on Android.
* Specify return address register for the unwind plan instead of explict
tracking the value of RA.
* Replace prologue detection heuristics (unreliable in several cases)
with a logic to follow the branch instructions and restore the CFI
value based on them. The target address for a branch should have the
same CFI as the source address (if they are in the same function).
* Handle symbols in ELF files where the symbol size is not specified
with calcualting their size based on the next symbol (already done
in MachO files).
* Fix architecture in FuncUnwinders with filling up the inforamtion
missing from the object file with the architecture of the target.
* Add code to read register wehn the value is set to "IsSame" as it
meanse the value of a register in the parent frame is the same as the
value in the current frame.
Differential revision: http://reviews.llvm.org/D10447
llvm-svn: 240533
Gcc for android use the leal instruction to substract from the stack
pointer in the prologue of a function call. This patch add basic support
for evaluating this instruction to support stack unwinding on
android-x86.
Differential revision: http://reviews.llvm.org/D8583
llvm-svn: 233178
Summary:
This is initial implementation of assembly profiler which only scans prologue/epilogue assembly instructions to create CFI instructions.
Reviewers: clayborg, jasonmolenda
Differential Revision: http://reviews.llvm.org/D7696
llvm-svn: 232619
This continues the effort to reduce header footprint and improve
build speed by removing clang and other unnecessary headers
from Target.h. In one case, some headers were included solely
for the purpose of declaring a nested class in Target, which was
not needed by anybody outside the class. In this case the
definition and implementation of the nested class were isolated
in the .cpp file so the header could be removed.
llvm-svn: 231107
Summary:
This change refactors UnwindPlan::Row to be able to store the fact that the CFA is value is set
by evaluating a dwarf expression (DW_CFA_def_cfa_expression). This is achieved by creating a new
class CFAValue and moving all CFA setting/getting code there. Note that code using the new
CFAValue::isDWARFExpression is not yet present and will be added in a follow-up patch. Therefore,
this patch should not change the functionality in any way.
Test Plan: Ran tests on Mac and Linux. No regressions detected.
Reviewers: jasonmolenda, clayborg
Subscribers: lldb-commits
Differential Revision: http://reviews.llvm.org/D7755
llvm-svn: 230210
changing it was in r219544 - after living on that for a few
months, I wanted to take another crack at this.
The disassembly-format setting still exists and the old format
can be user specified with a setting like
${current-pc-arrow}${addr-file-or-load}{ <${function.name-without-args}${function.concrete-only-addr-offset-no-padding}>}:
This patch was discussed in http://reviews.llvm.org/D7578
<rdar://problem/19726421>
llvm-svn: 229186
signed and unsigned types in comparisons.
For the text offset, use the addr_t type that is used elsewhere to get
these kinds of offsets, and which it is being compared against. This
seems to make things more consistent.
For the other, the numbers are clearly small and uninteresting, so just
cast them to the most boring 'int' type.
llvm-svn: 229085
Why? Debugger::FormatPrompt() would run through the format prompt every time and parse it and emit it piece by piece. It also did formatting differently depending on which key/value pair it was parsing.
The new code improves on this with the following features:
1 - Allow format strings to be parsed into a FormatEntity::Entry which can contain multiple child FormatEntity::Entry objects. This FormatEntity::Entry is a parsed version of what was previously always done in Debugger::FormatPrompt() so it is more efficient to emit formatted strings using the new parsed FormatEntity::Entry.
2 - Allows errors in format strings to be shown immediately when setting the settings (frame-format, thread-format, disassembly-format
3 - Allows auto completion by implementing a new OptionValueFormatEntity and switching frame-format, thread-format, and disassembly-format settings over to using it.
4 - The FormatEntity::Entry for each of the frame-format, thread-format, disassembly-format settings only replaces the old one if the format parses correctly
5 - Combines all consecutive string values together for efficient output. This means all "${ansi.*}" keys and all desensitized characters like "\n" "\t" "\0721" "\x23" will get combined with their previous strings
6 - ${*.script:} (like "${var.script:mymodule.my_var_function}") have all been switched over to use ${script.*:} "${script.var:mymodule.my_var_function}") to make the format easier to parse as I don't believe anyone was using these format string power user features.
7 - All key values pairs are defined in simple C arrays of entries so it is much easier to add new entries.
These changes pave the way for subsequent modifications where we can modify formats to do more (like control the width of value strings can do more and add more functionality more easily like string formatting to control the width, printf formats and more).
llvm-svn: 228207
saved/restored across a mid-function epilogue. We ignore
repeated push/pops of a register so once we saw one 'pop %rbp',
we'd ignore it the second time we saw it.
<rdar://problem/19417410>
llvm-svn: 225853
it will do the right thing on x86 routines with a mid-function
epilogue sequence (where the unwind rules need to be reinstalled
after the epilogue has completed).
<rdar://problem/19417410>
llvm-svn: 225773
Jason Molenda