128c0d037d
Summary: //reviews.llvm.org/D33035 added in 2017 basic support for intel-pt. I plan to improve it and use it to support reverse debugging. I fixed a couple of issues and now this plugin works again: 1. pythonlib needed to be linked against it for the SB framework. Linking was failing because of this 2. the decoding functionality was broken because it lacked handling for instruction events. It seems old versions of libipt, the actual decoding library, didn't require these, but modern version require it (you can read more here https://github.com/intel/libipt/blob/master/doc/howto_libipt.md). These events signal overflows of the internal PT buffer in the CPU, enable/disable events of tracing, async cpu events, interrupts, etc. I ended up refactoring a little bit the code to reduce code duplication. In another diff I'll implement some basic tests. This is a simple execution of the library: (lldb) target create "/data/users/wallace/rr-project/a.out" Current executable set to '/data/users/wallace/rr-project/a.out' (x86_64). (lldb) plugin load liblldbIntelFeatures.so (lldb) b main Breakpoint 1: where = a.out`main + 8 at test.cpp:10, address = 0x00000000004007fa (lldb) b test.cpp:14 Breakpoint 2: where = a.out`main + 50 at test.cpp:14, address = 0x0000000000400824 (lldb) r Process 902754 stopped * thread #1, name = 'a.out', stop reason = breakpoint 1.1 frame #0: 0x00000000004007fa a.out`main at test.cpp:10 7 } 8 9 int main() { -> 10 int z = 0; 11 for(int i = 0; i < 10000; i++) 12 z += fun(z); 13 Process 902754 launched: '/data/users/wallace/rr-project/a.out' (x86_64) (lldb) processor-trace start all (lldb) c Process 902754 resuming Process 902754 stopped * thread #1, name = 'a.out', stop reason = breakpoint 2.1 frame #0: 0x0000000000400824 a.out`main at test.cpp:14 11 for(int i = 0; i < 10000; i++) 12 z += fun(z); 13 -> 14 cout << z<< endl; 15 return 0; 16 } (lldb) processor-trace show-instr-log thread #1: tid=902754 0x7ffff72299b9 <+9>: addq $0x8, %rsp 0x7ffff72299bd <+13>: retq 0x4007ed <+16>: addl $0x1, %eax 0x4007f0 <+19>: leave 0x4007f1 <+20>: retq 0x400814 <+34>: addl %eax, -0x4(%rbp) 0x400817 <+37>: addl $0x1, -0x8(%rbp) 0x40081b <+41>: cmpl $0x270f, -0x8(%rbp) ; imm = 0x270F 0x400822 <+48>: jle 0x40080a ; <+24> at test.cpp:12 0x400822 <+48>: jle 0x40080a ; <+24> at test.cpp:12 ``` Subscribers: mgorny, lldb-commits Tags: #lldb Differential Revision: https://reviews.llvm.org/D76872
****************************************************************************
* README *
* *
* This file provides all the information regarding new CLI commands that *
* enable using various hardware features of Intel(R) architecture based *
* processors from LLDB's CLI. *
****************************************************************************
============
Introduction
============
A shared library has been developed to use various hardware features of
Intel(R) architecture based processors through LLDB's command line. The library
currently comprises of hardware features namely Intel(R) Processor Trace and
Intel(R) Memory Protection Extensions.
============
Details
============
A C++ based cli wrapper (cli-wrapper.cpp) has been developed here that
agglomerates all cli commands for various hardware features. This wrapper is
build to generate a shared library (lldbIntelFeatures) to provide all these
commands.
For each hardware feature, separate cli commands have been developed that are
provided by wrappers (cli-wrapper-pt.cpp and cli-wrapper-mpxtable.cpp) residing
in feature specific folders ("intel-pt" and "intel-mpx" respectively).
For details regarding cli commands of each feature, please refer to these
feature specific wrappers.
============
How to Build
============
The shared library (lldbIntelFeatures) has a cmake based build and can be built
while building LLDB with cmake. "cli-wrapper.cpp" file is compiled along with all
the feature specific source files (residing in feature specific folders).
Furthermore, flexibility is provided to the user to include/exclude a particular
feature while building lldbIntelFeatures library. This is done by flags described
below:
- LLDB_BUILD_INTEL_PT - The flag enables building of Intel(R) Processor Trace
feature (inside intel-pt folder). This flag defaults to "OFF" meaning the
feature is excluded while building lldbIntelFeatures library. Set it to "ON"
in order to include it.
- LLDB_BUILD_INTEL_MPX - Enables building Intel(R) Memory Protection Extensions
feature (inside intel-mpx folder). This flag defaults to "ON" meaning
the feature is excluded while building lldbIntelFeatures library.
Please refer to README files in feature specific folders to know about additional
flags that need to be set in order to build that feature successfully.
============
How to Use
============
All CLI commands provided by this shared library can be used through the LLDB's
CLI by executing "plugin load <shared_lib_name>" on LLDB CLI. shared_lib_name here
is lldbIntelFeatures
============
Description
============
Please refer to README_CLI file of each feature to know about details of CLI
commands.