The bcc build with latest clang/llvm 7.0 has the following
compilation error:

 /home/yhs/work/llvm/build/install/lib/libclangCodeGen.a(CodeGenAction.cpp.o):
  In function `clang::BackendConsumer::Initialize(clang::ASTContext&)':
  CodeGenAction.cpp:(.text._ZN5clang15BackendConsumer10InitializeERNS_10ASTContextE[_ZN5clang15BackendConsumer10InitializeERNS_10ASTContextE]+0xc): undefined reference to `clang::FrontendTimesIsEnabled'
 ...

The latest clang defined clang::FrontendTimesIsEnabled in
libclangFrontend.a and used in libclangCodeGen.a.

Due to the library order specified in clang_libs.cmake:
  # order is important
  set(clang_libs
    ${libclangFrontend}
    ...
    ${libclangCodeGen}
and the fact clang_libs here is used to build bcc-static,
the definition of clang::FrontendTimesIsEnabled is dropped
since nobody used it before the definition is checked by the compiler.

The fix here is to keep all the definitions/uses for clang_libs/llvm_libs
when buildint static library.

Tested on clang 4.0, 5.0, 6.0 and latest 7.0, all works fine.
Signed-off-by: Yonghong Song <yhs@fb.com>

introduce {attach|detach}_raw_tracepoint API

Update docs/kernel_versions

Update list of main features and supported map types.

Also update list of architectures supporting JIT, and main features
list, with important upcoming changes (x86_32 for JIT, bpfilter and
AF_XDP for main features).

Also add notes on top of the lists about how to obtain the items of each
list.

Remove speculative map types with no link or schedule.

- Update links in doc (make them point from net-next to linux, when
  relevant).
- Add helpers bpf_xdp_adjust_tail() and bpf_skb_get_xfrm_state() to
  documentation and headers.
- Synchronise helpers with latest net-next.

The motivation comes from pull request #1689.
It attached a kprobe bpf program to kernel function
ttwu_do_wakeup for more accurate tracing.
Unfortunately, it broke runqlat.py in my
4.17 environment since ttwu_do_wakeup function
is inlined in my kernel with gcc 7.3.1.

4.17 introduced raw_tracepoint and this patch
added the relevant API to bcc. With this,
we can use tracepoints
sched:{sched_wakeup, sched_wakeup_new, sched_switch}
to measure runq latency more reliably.
Signed-off-by: Yonghong Song <yhs@fb.com>

Misc improvements to C++ API and example

introduce C++ get_syscall_fnname API

Support Cgroup Array in BCC

This fixed issue #1695 for C++. The example
HelloWorld.cc and tests test_libbcc also got fixed.
Signed-off-by: Yonghong Song <yhs@fb.com>

document cflags argument to BPF()

Refactor profile.py stack id error handling

using get_syscall_fnname to get kprobe func name for tools

Refactor offwaketime stack id error handling

introduce new BPF APIs to get kernel syscall entry func name/prefix

Fixed tools which are attached to syscall entry functions
"sys_*". Instead, use get_syscall_fnname to get
proper names.
Signed-off-by: Yonghong Song <yhs@fb.com>

As described in issue #1695, on 4.17 for syscalls on x86,
both sys_<fnname> and SyS_<fnname> are gone, the replacements
are __ia32_sys_sync and __x64_sys_sync.
The commit in Linus tree:
https://github.com/torvalds/linux/commit/d5a00528b58cdb2c71206e18bd021e34c4eab878

This patch introduced two APIs for python BPF object.
The API get_syscall_prefix() returns the prefix "sys_"/"__x64_sys_".
The API get_syscall_fnname(name) returns kernel function name for the syscall,
e.g., on x64, get_syscall_fnname("clone") will return "sys_clone" if kernel
has it, otherwise, "__x64_sys_clone".
get_syscall_prefix() is mostly useful for the regex func specifier of
attach_kprobe().

This patch only fixed the code using python API on examples and tests directory.

TOTO: python on tools directory, C++ and lua
Signed-off-by: Yonghong Song <yhs@fb.com>

print out more useful attach_kprobe failure information

As stated in issue #1695, the following commit
https://github.com/torvalds/linux/commit/5c8dad48e4f53d6fd0a7e4f95d7c1c983374de88
removed corresponding dmesg when attach_kprobe failed, and
userspace needs to print out proper error messages.
Signed-off-by: Yonghong Song <yhs@fb.com>

Add -c option for profile.py

Fix offwaketime PID / TGID handling

Refactor offcputime stack id error handling

Use better kprobes for runqlat.py

Fix probe name encoding in Python 3

fix profile.py with latest net-next

fixing bpflist