[PATCH v4 00/18] perf clang: Builtin clang and perfhook support

[PATCH v4 00/18] perf clang: Builtin clang and perfhook support

[Wang Nan]

This is version 4 of perf builtin clang and perfhook patch series.

In this patch set:
  1. Cleanup options passed to clang.
  2. Check LLVM version. Fail if llvm version < 3.9.0, and
     warn when it > 3.9.0. More version will be allowed after
     releasing of LLVM 3.9.1 / 4.0.0.
  3. Support dynamic linking LLVM and clang libraries.
  4. Rebase to Arnaldo's newest perf/core.

Wang Nan (18):
  perf build: Check LLVM version in feature check
  perf build: Support dynamic linking clang libraries
  perf clang: Cleanup clang options
  perf clang: Pass full path to builtin clang
  perf clang: Pass CFLAGS to builtin clang
  perf clang jit: Wrap llvm::Module using PerfModule
  perf clang jit: Insignt BPF and JIT functions in a Module
  perf clang jit: add PerfModule::doJIT to JIT perfhook functions
  perf clang jit: Export functions for jitted code
  perf clang jit: Actually JIT and hook in bpf loader
  perf clang jit: Collect the lowest address in maps section as map_base
  perf clang jit: Retrive fd of BPF map from its offset
  perf clang jit: Allow jitted perf hook access BPF maps
  perf clang: Link BPF functions declaration into perf
  perf clang: Declare BPF functions for BPF scripts automatically
  perf clang: Include helpers to BPF scripts
  perf clang builtin: Define hook helpers by default
  perf clang jit: Export getpid() to perf hook

 tools/build/feature/Makefile                  |   8 +-
 tools/build/feature/test-llvm-version.cpp     |  12 +
 tools/build/feature/test-llvm.cpp             |   5 +
 tools/perf/Makefile.config                    |   8 +-
 tools/perf/Makefile.perf                      |  20 +-
 tools/perf/tests/Build                        |   2 +-
 tools/perf/tests/bpf-script-example.c         |  30 ++-
 tools/perf/tests/bpf-script-test-kbuild.c     |   2 +
 tools/perf/tests/bpf-script-test-prologue.c   |   6 +-
 tools/perf/tests/bpf-script-test-relocation.c |  17 +-
 tools/perf/tests/clang.c                      |   4 +
 tools/perf/util/Build                         |   1 +
 tools/perf/util/bpf-loader.c                  |  85 ++++++-
 tools/perf/util/bpf-loader.h                  |  19 ++
 tools/perf/util/c++/Build                     |   2 +
 tools/perf/util/c++/bpf-funcs-str.c           |  49 ++++
 tools/perf/util/c++/bpf-helper-str.c          |  23 ++
 tools/perf/util/c++/clang-bpf-includes.h      |  13 +
 tools/perf/util/c++/clang-c.h                 |  24 +-
 tools/perf/util/c++/clang-test.cpp            |  51 +++-
 tools/perf/util/c++/clang.cpp                 | 335 ++++++++++++++++++++++++--
 tools/perf/util/c++/clang.h                   |  47 +++-
 tools/perf/util/jit-helpers.c                 |  57 +++++
 tools/perf/util/jit-helpers.h                 |  28 +++
 tools/perf/util/llvm-utils.h                  |   9 +-
 25 files changed, 802 insertions(+), 55 deletions(-)
 create mode 100644 tools/build/feature/test-llvm-version.cpp
 create mode 100644 tools/perf/util/c++/bpf-funcs-str.c
 create mode 100644 tools/perf/util/c++/bpf-helper-str.c
 create mode 100644 tools/perf/util/c++/clang-bpf-includes.h
 create mode 100644 tools/perf/util/jit-helpers.c
 create mode 100644 tools/perf/util/jit-helpers.h

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Joe Stringer <joe@ovn.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
-- 
2.10.1

[PATCH v4 01/18] perf build: Check LLVM version in feature check

[Wang Nan]

Cancel builtin llvm and clang support when LLVM version is
less than 3.9.0: following commits uses newer API.

Since Clang/LLVM's API is not guaranteed to be stable,
add a test-llvm-version.cpp feature checker, issue warning if
LLVM found in compiling environment is not tested yet.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Joe Stringer <joe@ovn.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
 tools/build/feature/Makefile              |  8 ++++++--
 tools/build/feature/test-llvm-version.cpp | 12 ++++++++++++
 tools/build/feature/test-llvm.cpp         |  5 +++++
 tools/perf/Makefile.config                |  8 ++++++--
 4 files changed, 29 insertions(+), 4 deletions(-)
 create mode 100644 tools/build/feature/test-llvm-version.cpp

diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
index 303196c..b564a2e 100644
--- a/tools/build/feature/Makefile
+++ b/tools/build/feature/Makefile
@@ -231,14 +231,18 @@ $(OUTPUT)test-jvmti.bin:
 	$(BUILD)
 
 $(OUTPUT)test-llvm.bin:
-	$(BUILDXX) -std=gnu++11 					\
+	$(BUILDXX) -std=gnu++11 				\
 		-I$(shell $(LLVM_CONFIG) --includedir) 		\
 		-L$(shell $(LLVM_CONFIG) --libdir)		\
 		$(shell $(LLVM_CONFIG) --libs Core BPF)		\
 		$(shell $(LLVM_CONFIG) --system-libs)
 
+$(OUTPUT)test-llvm-version.bin:
+	$(BUILDXX) -std=gnu++11 				\
+		-I$(shell $(LLVM_CONFIG) --includedir)
+
 $(OUTPUT)test-clang.bin:
-	$(BUILDXX) -std=gnu++11 					\
+	$(BUILDXX) -std=gnu++11 				\
 		-I$(shell $(LLVM_CONFIG) --includedir) 		\
 		-L$(shell $(LLVM_CONFIG) --libdir)		\
 		-Wl,--start-group -lclangBasic -lclangDriver	\
diff --git a/tools/build/feature/test-llvm-version.cpp b/tools/build/feature/test-llvm-version.cpp
new file mode 100644
index 0000000..e86b642
--- /dev/null
+++ b/tools/build/feature/test-llvm-version.cpp
@@ -0,0 +1,12 @@
+#include <cstdio>
+#include "llvm/Config/llvm-config.h"
+
+#define NUM_VERSION (((LLVM_VERSION_MAJOR) << 16) + (LLVM_VERSION_MINOR << 8) + LLVM_VERSION_PATCH)
+#define pass int main() {printf("%x\n", NUM_VERSION); return 0;}
+
+#if NUM_VERSION >= 0x030900
+pass
+#else
+# error This LLVM is not tested yet.
+#endif
+
diff --git a/tools/build/feature/test-llvm.cpp b/tools/build/feature/test-llvm.cpp
index d8d2cee..455a332 100644
--- a/tools/build/feature/test-llvm.cpp
+++ b/tools/build/feature/test-llvm.cpp
@@ -1,5 +1,10 @@
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/raw_ostream.h"
+#define NUM_VERSION (((LLVM_VERSION_MAJOR) << 16) + (LLVM_VERSION_MINOR << 8) + LLVM_VERSION_PATCH)
+
+#if NUM_VERSION < 0x030900
+# error "LLVM version too low"
+#endif
 int main()
 {
 	llvm::errs() << "Hello World!\n";
diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index 09c2a98..2f4d5b0 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -802,12 +802,13 @@ ifdef LIBCLANGLLVM
     msg := $(warning No g++ found, disable clang and llvm support. Please install g++)
   else
     $(call feature_check,llvm)
+    $(call feature_check,llvm-version)
     ifneq ($(feature-llvm), 1)
-      msg := $(warning No libLLVM found, disable clang and llvm support. Please install llvm-dev)
+      msg := $(warning No libLLVM found, disable clang and llvm support. Please install llvm-dev (>= 3.9.0))
     else
       $(call feature_check,clang)
       ifneq ($(feature-clang), 1)
-        msg := $(warning No libclang found, disable clang and llvm support. Please install libclang-dev)
+        msg := $(warning No libclang found, disable clang and llvm support. Please install libclang-dev (>= 3.9.0))
       else
         CFLAGS += -DHAVE_LIBCLANGLLVM_SUPPORT
         CXXFLAGS += -DHAVE_LIBCLANGLLVM_SUPPORT -I$(shell $(LLVM_CONFIG) --includedir)
@@ -816,6 +817,9 @@ ifdef LIBCLANGLLVM
 	USE_CXX = 1
 	USE_LLVM = 1
 	USE_CLANG = 1
+        ifneq ($(feature-llvm-version),1)
+          msg := $(warning This version of llvm is not tested. May cause building error)
+        endif
       endif
     endif
   endif
-- 
2.10.1

[PATCH v4 02/18] perf build: Support dynamic linking clang libraries

[Wang Nan]

Statical linking result a very large perf executable. This patch makes
perf link clang libraries dynamically by using '-lclangBasic' style
linking option. If dynamic clang libraries are detected, gcc will use
them by default.

 Test result:

 (Build clang/llvm dynamically by setting -DBUILD_SHARED_LIBS=ON
  in its cmake configuration.)

 $ size ~/perf
 text      data     bss         dec        hex      filename
 4223234   754544   23956048    28933826   1b97ec2  /home/wn/perf

 $ strip ~/perf
 $ ls -sh ~/perf
 4.8M /home/wn/perf

 Compare with statical linking:
 $ ls -sh ~/perf
 969M /home/wn/perf
 $ strip ~/perf
 $ ls -sh ~/perf
 52M /home/wn/perf

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
 tools/perf/Makefile.perf | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 10495c9..192f2d6 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -329,9 +329,25 @@ endif
 LIBS = -Wl,--whole-archive $(PERFLIBS) -Wl,--no-whole-archive -Wl,--start-group $(EXTLIBS) -Wl,--end-group
 
 ifeq ($(USE_CLANG), 1)
+  # Only partial of the required clang libraries are listed.
+  #
+  # In case of dynamical linking, if clang is built and installed
+  # correctly, ld can infer the full list automatically. However,
+  # I observed a potential bug in 3.9.0 that four libraries
+  # (ASTMatchers, Format Rewrite and ToolingCore) are lost.
+  #
+  # In case of statical linking, providing the full list causes
+  # linking time dramatically increases because of --{start,end}-group.
+  #
+  # If linking error, replace CLANGLIBS_LIST with the full list
+  # and try again.
+  #
+  # The full list should be:
+  #
+  # Basic CodeGen Frontend Tooling AST Lex Driver Edit Parse Sema
+  # Serialization ASTMatchers Format Rewrite ToolingCore Analysis
   CLANGLIBS_LIST = AST Basic CodeGen Driver Frontend Lex Tooling Edit Sema Analysis Parse Serialization
-  LIBCLANG = $(foreach l,$(CLANGLIBS_LIST),$(wildcard $(shell $(LLVM_CONFIG) --libdir)/libclang$(l).a))
-  LIBS += -Wl,--start-group $(LIBCLANG) -Wl,--end-group
+  LIBS += -L$(shell $(LLVM_CONFIG) --libdir) -Wl,--start-group $(foreach l,$(CLANGLIBS_LIST),-lclang$(l)) -Wl,--end-group
 endif
 
 ifeq ($(USE_LLVM), 1)
-- 
2.10.1

[PATCH v4 03/18] perf clang: Cleanup clang options

[Wang Nan]

Follow Alexei's suggestion, remove "-ferror-limit=19",
"-fmessage-length=127", "-vectorize-loops" and "-vectorize-slp"
clang options: they are meaningless. Add comment for
"-Wno-unused-value" and "-Wno-pointer-sign".

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
 tools/perf/util/c++/clang.cpp | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/tools/perf/util/c++/clang.cpp b/tools/perf/util/c++/clang.cpp
index 1e97415..7fe0222c5 100644
--- a/tools/perf/util/c++/clang.cpp
+++ b/tools/perf/util/c++/clang.cpp
@@ -41,13 +41,10 @@ createCompilerInvocation(llvm::opt::ArgStringList CFlags, StringRef& Path,
 		"-cc1",
 		"-triple", "bpf-pc-linux",
 		"-fsyntax-only",
-		"-ferror-limit", "19",
-		"-fmessage-length", "127",
 		"-O2",
 		"-nostdsysteminc",
 		"-nobuiltininc",
-		"-vectorize-loops",
-		"-vectorize-slp",
+		/* Suppress warnings when using kernel headers */
 		"-Wno-unused-value",
 		"-Wno-pointer-sign",
 		"-x", "c"};
-- 
2.10.1

[PATCH v4 04/18] perf clang: Pass full path to builtin clang

[Wang Nan]

If clang changes its working directory, relative path passed to
perf_clang__compile_bpf() becomes invalid. Before running clang,
convert it to absolute path so file can be found even working directory
is changed.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
 tools/perf/util/c++/clang.cpp | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/c++/clang.cpp b/tools/perf/util/c++/clang.cpp
index 7fe0222c5..340c948 100644
--- a/tools/perf/util/c++/clang.cpp
+++ b/tools/perf/util/c++/clang.cpp
@@ -13,6 +13,7 @@
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/TextDiagnosticPrinter.h"
 #include "clang/Tooling/Tooling.h"
+#include "llvm/ADT/SmallString.h"
 #include "llvm/IR/LegacyPassManager.h"
 #include "llvm/IR/Module.h"
 #include "llvm/Option/Option.h"
@@ -161,7 +162,7 @@ void perf_clang__cleanup(void)
 	llvm::llvm_shutdown();
 }
 
-int perf_clang__compile_bpf(const char *filename,
+int perf_clang__compile_bpf(const char *_filename,
 			    void **p_obj_buf,
 			    size_t *p_obj_buf_sz)
 {
@@ -170,8 +171,11 @@ int perf_clang__compile_bpf(const char *filename,
 	if (!p_obj_buf || !p_obj_buf_sz)
 		return -EINVAL;
 
+	llvm::SmallString<PATH_MAX> FileName(_filename);
+	llvm::sys::fs::make_absolute(FileName);
+
 	llvm::opt::ArgStringList CFlags;
-	auto M = getModuleFromSource(std::move(CFlags), filename);
+	auto M = getModuleFromSource(std::move(CFlags), FileName.data());
 	if (!M)
 		return  -EINVAL;
 	auto O = getBPFObjectFromModule(&*M);
-- 
2.10.1

[PATCH v4 05/18] perf clang: Pass CFLAGS to builtin clang

[Wang Nan]

Pass -DLINUX_VERSION_CODE, -D__NR_CPUS__, llvm.clang-opt config options
and CFLAGS detected by kbuild detector to builtin clang so BPF scripts
can use kernel headers and user defined options like external clang
compiler.

Test:
  # perf record -v --dry-run -e tools/perf/tests/bpf-script-test-kbuild.c ls 2>&1 | grep built
  bpf: builtin compiling successful

Committer notes:

Before installing the required clang/llvm devel files to have it
builtin:

  # perf record -v --dry-run -e tools/perf/tests/bpf-script-test-kbuild.c ls 2>&1 | grep built
  bpf: builtin compiling failed: -95, try external compiler

I.e. it falls back to using the external compiler.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
 tools/perf/util/c++/clang.cpp | 105 ++++++++++++++++++++++++++++++++++++++++--
 tools/perf/util/llvm-utils.h  |   9 +++-
 2 files changed, 109 insertions(+), 5 deletions(-)

diff --git a/tools/perf/util/c++/clang.cpp b/tools/perf/util/c++/clang.cpp
index 340c948..6308aaf 100644
--- a/tools/perf/util/c++/clang.cpp
+++ b/tools/perf/util/c++/clang.cpp
@@ -27,6 +27,8 @@
 
 #include "clang.h"
 #include "clang-c.h"
+#include "llvm-utils.h"
+#include "util-cxx.h"
 
 namespace perf {
 
@@ -144,6 +146,101 @@ getBPFObjectFromModule(llvm::Module *Module)
 	return std::move(Buffer);
 }
 
+class ClangOptions {
+	llvm::SmallString<PATH_MAX> FileName;
+	llvm::SmallString<64> KVerDef;
+	llvm::SmallString<64> NRCpusDef;
+	char *kbuild_dir;
+	char *kbuild_include_opts;
+	char *clang_opt;
+public:
+	ClangOptions(const char *filename) : FileName(filename),
+					     KVerDef(""),
+					     NRCpusDef(""),
+					     kbuild_dir(NULL),
+					     kbuild_include_opts(NULL),
+					     clang_opt(NULL)
+	{
+		llvm::sys::fs::make_absolute(FileName);
+
+		unsigned int kver;
+		if (!fetch_kernel_version(&kver, NULL, 0))
+			KVerDef = "-DLINUX_VERSION_CODE=" + std::to_string(kver);
+
+		int nr_cpus = llvm__get_nr_cpus();
+		if (nr_cpus > 0)
+			NRCpusDef = "-D__NR_CPUS__=" + std::to_string(nr_cpus);
+
+		if (llvm_param.clang_opt)
+			clang_opt = strdup(llvm_param.clang_opt);
+
+		llvm__get_kbuild_opts(&kbuild_dir, &kbuild_include_opts);
+		if (!kbuild_dir || !kbuild_include_opts) {
+			free(kbuild_dir);
+			free(kbuild_include_opts);
+			kbuild_dir = kbuild_include_opts = NULL;
+		}
+	}
+
+	~ClangOptions()
+	{
+		free(kbuild_dir);
+		free(kbuild_include_opts);
+		free(clang_opt);
+	}
+
+	static void fillCFlagsFromString(opt::ArgStringList &CFlags, char *s, bool check = false)
+	{
+		if (!s)
+			return;
+
+		SmallVector<StringRef, 0> Terms;
+		StringRef Opts(s);
+		Opts.split(Terms, ' ');
+
+		for (auto i = Terms.begin(); i != Terms.end(); i++)
+			s[i->end() - Opts.begin()] = '\0';
+
+		for (auto i = Terms.begin(); i != Terms.end(); i++) {
+			if (!check) {
+				CFlags.push_back(i->begin());
+				continue;
+			}
+
+			if (i->startswith("-I"))
+				CFlags.push_back(i->begin());
+			else if (i->startswith("-D"))
+				CFlags.push_back(i->begin());
+			else if (*i == "-include") {
+				CFlags.push_back((i++)->begin());
+				/* Let clang report this error */
+				if (i == Terms.end())
+					break;
+				CFlags.push_back(i->begin());
+			}
+		}
+	}
+
+	void getCFlags(opt::ArgStringList &CFlags)
+	{
+		CFlags.push_back(KVerDef.c_str());
+		CFlags.push_back(NRCpusDef.c_str());
+
+		fillCFlagsFromString(CFlags, clang_opt);
+		fillCFlagsFromString(CFlags, kbuild_include_opts, true);
+
+		if (kbuild_dir) {
+			CFlags.push_back("-working-directory");
+			CFlags.push_back(kbuild_dir);
+		}
+	}
+
+	const char *getFileName(void)
+	{
+		return FileName.c_str();
+	}
+};
+
 }
 
 extern "C" {
@@ -171,11 +268,11 @@ int perf_clang__compile_bpf(const char *_filename,
 	if (!p_obj_buf || !p_obj_buf_sz)
 		return -EINVAL;
 
-	llvm::SmallString<PATH_MAX> FileName(_filename);
-	llvm::sys::fs::make_absolute(FileName);
-
+	ClangOptions Opts(_filename);
 	llvm::opt::ArgStringList CFlags;
-	auto M = getModuleFromSource(std::move(CFlags), FileName.data());
+
+	Opts.getCFlags(CFlags);
+	auto M = getModuleFromSource(std::move(CFlags), Opts.getFileName());
 	if (!M)
 		return  -EINVAL;
 	auto O = getBPFObjectFromModule(&*M);
diff --git a/tools/perf/util/llvm-utils.h b/tools/perf/util/llvm-utils.h
index c87a2a9..263a00d 100644
--- a/tools/perf/util/llvm-utils.h
+++ b/tools/perf/util/llvm-utils.h
@@ -5,7 +5,11 @@
 #ifndef __LLVM_UTILS_H
 #define __LLVM_UTILS_H
 
-#include "debug.h"
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <errno.h>
 
 struct llvm_param {
 	/* Path of clang executable */
@@ -56,4 +60,7 @@ void llvm__get_kbuild_opts(char **kbuild_dir, char **kbuild_include_opts);
 int llvm__get_nr_cpus(void);
 
 void llvm__dump_obj(const char *path, void *obj_buf, size_t size);
+#ifdef __cplusplus
+}
+#endif
 #endif
-- 
2.10.1

[PATCH v4 06/18] perf clang jit: Wrap llvm::Module using PerfModule

[Wang Nan]

Use PerfModule wrap llvm::Module and return perf::PerfModule in APIs to
replace llvm::Module. Following commits are going to add new functions
to PerfModule.

getBPFObjectFromModule is merged to a method of perf::PerfModule.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
 tools/perf/util/c++/clang-test.cpp | 10 +++++-----
 tools/perf/util/c++/clang.cpp      | 20 +++++++++++++-------
 tools/perf/util/c++/clang.h        | 22 ++++++++++++++++------
 3 files changed, 34 insertions(+), 18 deletions(-)

diff --git a/tools/perf/util/c++/clang-test.cpp b/tools/perf/util/c++/clang-test.cpp
index 9b11e8c..fb05e56 100644
--- a/tools/perf/util/c++/clang-test.cpp
+++ b/tools/perf/util/c++/clang-test.cpp
@@ -13,18 +13,18 @@ public:
 	~perf_clang_scope() {perf_clang__cleanup();}
 };
 
-static std::unique_ptr<llvm::Module>
+static std::unique_ptr<perf::PerfModule>
 __test__clang_to_IR(void)
 {
 	unsigned int kernel_version;
 
 	if (fetch_kernel_version(&kernel_version, NULL, 0))
-		return std::unique_ptr<llvm::Module>(nullptr);
+		return std::unique_ptr<perf::PerfModule>(nullptr);
 
 	std::string cflag_kver("-DLINUX_VERSION_CODE=" +
 				std::to_string(kernel_version));
 
-	std::unique_ptr<llvm::Module> M =
+	std::unique_ptr<perf::PerfModule> M =
 		perf::getModuleFromSource({cflag_kver.c_str()},
 					  "perf-test.c",
 					  test_llvm__bpf_base_prog);
@@ -39,7 +39,7 @@ int test__clang_to_IR(void)
 	auto M = __test__clang_to_IR();
 	if (!M)
 		return -1;
-	for (llvm::Function& F : *M)
+	for (llvm::Function& F : *(M->getModule()))
 		if (F.getName() == "bpf_func__SyS_epoll_wait")
 			return 0;
 	return -1;
@@ -53,7 +53,7 @@ int test__clang_to_obj(void)
 	if (!M)
 		return -1;
 
-	auto Buffer = perf::getBPFObjectFromModule(&*M);
+	auto Buffer = M->toBPFObject();
 	if (!Buffer)
 		return -1;
 	return 0;
diff --git a/tools/perf/util/c++/clang.cpp b/tools/perf/util/c++/clang.cpp
index 6308aaf..042db68 100644
--- a/tools/perf/util/c++/clang.cpp
+++ b/tools/perf/util/c++/clang.cpp
@@ -61,7 +61,7 @@ createCompilerInvocation(llvm::opt::ArgStringList CFlags, StringRef& Path,
 	return CI;
 }
 
-static std::unique_ptr<llvm::Module>
+static std::unique_ptr<PerfModule>
 getModuleFromSource(llvm::opt::ArgStringList CFlags,
 		    StringRef Path, IntrusiveRefCntPtr<vfs::FileSystem> VFS)
 {
@@ -77,12 +77,12 @@ getModuleFromSource(llvm::opt::ArgStringList CFlags,
 
 	std::unique_ptr<CodeGenAction> Act(new EmitLLVMOnlyAction(&*LLVMCtx));
 	if (!Clang.ExecuteAction(*Act))
-		return std::unique_ptr<llvm::Module>(nullptr);
+		return std::unique_ptr<PerfModule>(nullptr);
 
-	return Act->takeModule();
+	return std::unique_ptr<PerfModule>(new PerfModule(std::move(Act->takeModule())));
 }
 
-std::unique_ptr<llvm::Module>
+std::unique_ptr<PerfModule>
 getModuleFromSource(llvm::opt::ArgStringList CFlags,
 		    StringRef Name, StringRef Content)
 {
@@ -103,15 +103,21 @@ getModuleFromSource(llvm::opt::ArgStringList CFlags,
 	return getModuleFromSource(std::move(CFlags), Name, OverlayFS);
 }
 
-std::unique_ptr<llvm::Module>
+std::unique_ptr<PerfModule>
 getModuleFromSource(llvm::opt::ArgStringList CFlags, StringRef Path)
 {
 	IntrusiveRefCntPtr<vfs::FileSystem> VFS(vfs::getRealFileSystem());
 	return getModuleFromSource(std::move(CFlags), Path, VFS);
 }
 
+PerfModule::PerfModule(std::unique_ptr<llvm::Module>&& M) : Module(std::move(M))
+{
+
+}
+
+
 std::unique_ptr<llvm::SmallVectorImpl<char>>
-getBPFObjectFromModule(llvm::Module *Module)
+PerfModule::toBPFObject(void)
 {
 	using namespace llvm;
 
@@ -275,7 +281,7 @@ int perf_clang__compile_bpf(const char *_filename,
 	auto M = getModuleFromSource(std::move(CFlags), Opts.getFileName());
 	if (!M)
 		return  -EINVAL;
-	auto O = getBPFObjectFromModule(&*M);
+	auto O = M->toBPFObject();
 	if (!O)
 		return -EINVAL;
 
diff --git a/tools/perf/util/c++/clang.h b/tools/perf/util/c++/clang.h
index dd8b042..cbb291b 100644
--- a/tools/perf/util/c++/clang.h
+++ b/tools/perf/util/c++/clang.h
@@ -11,16 +11,26 @@ namespace perf {
 
 using namespace llvm;
 
-std::unique_ptr<Module>
+class PerfModule {
+private:
+	std::unique_ptr<llvm::Module> Module;
+public:
+	inline llvm::Module *getModule(void)
+	{
+		return Module.get();
+	}
+
+	PerfModule(std::unique_ptr<llvm::Module>&& M);
+
+	std::unique_ptr<llvm::SmallVectorImpl<char>> toBPFObject(void);
+};
+
+std::unique_ptr<PerfModule>
 getModuleFromSource(opt::ArgStringList CFlags,
 		    StringRef Name, StringRef Content);
 
-std::unique_ptr<Module>
+std::unique_ptr<PerfModule>
 getModuleFromSource(opt::ArgStringList CFlags,
 		    StringRef Path);
-
-std::unique_ptr<llvm::SmallVectorImpl<char>>
-getBPFObjectFromModule(llvm::Module *Module);
-
 }
 #endif
-- 
2.10.1

[PATCH v4 07/18] perf clang jit: Insignt BPF and JIT functions in a Module

[Wang Nan]

Identify BPF functions, JIT functions and maps during init. Functions in
section starting with "perfhook:" are JIT functions. They will be JIT
compiled and hooked at perfhooks.

During init of PerfModule, mark JIT functions as AvailableExternallyLinkage.
LLVM skips functions with linkage like this so they won't be compiled
into BPF objects.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Alexei Starovoitov <ast@fb.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
 tools/perf/util/c++/clang.cpp | 38 ++++++++++++++++++++++++++++++++++++++
 tools/perf/util/c++/clang.h   |  7 +++++++
 2 files changed, 45 insertions(+)

diff --git a/tools/perf/util/c++/clang.cpp b/tools/perf/util/c++/clang.cpp
index 042db68..8a0f818 100644
--- a/tools/perf/util/c++/clang.cpp
+++ b/tools/perf/util/c++/clang.cpp
@@ -112,15 +112,53 @@ getModuleFromSource(llvm::opt::ArgStringList CFlags, StringRef Path)
 
 PerfModule::PerfModule(std::unique_ptr<llvm::Module>&& M) : Module(std::move(M))
 {
+	for (llvm::Function& F : *Module) {
+		if (F.getLinkage() != llvm::GlobalValue::ExternalLinkage)
+			continue;
+
+		if (StringRef(F.getSection()).startswith("perfhook:"))
+			JITFunctions.insert(&F);
+		else
+			BPFFunctions.insert(&F);
+	}
 
+	for (auto V = Module->global_begin(); V != Module->global_end(); V++) {
+		llvm::GlobalVariable *GV = &*V;
+		if (StringRef(GV->getSection()) == llvm::StringRef("maps"))
+			Maps.insert(GV);
+	}
 }
 
+void PerfModule::prepareBPF(void)
+{
+	/*
+	 * setLinkage(AvailableExternallyLinkage) causes LLVM
+	 * blindly skip the function. They still exist in Module
+	 * so we can bring them back by resetting linkage to
+	 * ExternalLinkage.
+	 */
+	for (llvm::Function *F : JITFunctions)
+		F->setLinkage(llvm::GlobalValue::AvailableExternallyLinkage);
+	for (llvm::Function *F : BPFFunctions)
+		F->setLinkage(llvm::GlobalValue::ExternalLinkage);
+
+}
+
+void PerfModule::prepareJIT(void)
+{
+	for (llvm::Function *F : BPFFunctions)
+		F->setLinkage(llvm::GlobalValue::AvailableExternallyLinkage);
+	for (llvm::Function *F : JITFunctions)
+		F->setLinkage(llvm::GlobalValue::ExternalLinkage);
+
+}
 
 std::unique_ptr<llvm::SmallVectorImpl<char>>
 PerfModule::toBPFObject(void)
 {
 	using namespace llvm;
 
+	prepareBPF();
 	std::string TargetTriple("bpf-pc-linux");
 	std::string Error;
 	const Target* Target = TargetRegistry::lookupTarget(TargetTriple, Error);
diff --git a/tools/perf/util/c++/clang.h b/tools/perf/util/c++/clang.h
index cbb291b..1eb71a6 100644
--- a/tools/perf/util/c++/clang.h
+++ b/tools/perf/util/c++/clang.h
@@ -6,6 +6,7 @@
 #include "llvm/IR/Module.h"
 #include "llvm/Option/Option.h"
 #include <memory>
+#include <set>
 
 namespace perf {
 
@@ -14,6 +15,12 @@ using namespace llvm;
 class PerfModule {
 private:
 	std::unique_ptr<llvm::Module> Module;
+
+	std::set<llvm::GlobalVariable *> Maps;
+	std::set<llvm::Function *> BPFFunctions;
+	std::set<llvm::Function *> JITFunctions;
+	void prepareBPF(void);
+	void prepareJIT(void);
 public:
 	inline llvm::Module *getModule(void)
 	{
-- 
2.10.1

[PATCH v4 08/18] perf clang jit: add PerfModule::doJIT to JIT perfhook functions

[Wang Nan]

PerfModule::doJIT JIT compile perfhook functions and saves result into
a map. Add a test case for it.

At this stage perfhook functions can do no useful things because they
can't invoke external functions and can't return value. Following
commits are going to make improvment.

Don't hook functions right after jitted because bpf_object is unavailable
during jitting but it should be the context of jitted functions.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Alexei Starovoitov <ast@fb.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
 tools/perf/tests/bpf-script-example.c |  8 ++++
 tools/perf/tests/clang.c              |  4 ++
 tools/perf/util/c++/clang-c.h         |  2 +
 tools/perf/util/c++/clang-test.cpp    | 32 +++++++++++++++-
 tools/perf/util/c++/clang.cpp         | 71 +++++++++++++++++++++++++++++++++++
 tools/perf/util/c++/clang.h           | 13 +++++++
 6 files changed, 128 insertions(+), 2 deletions(-)

diff --git a/tools/perf/tests/bpf-script-example.c b/tools/perf/tests/bpf-script-example.c
index 268e5f8..265036e 100644
--- a/tools/perf/tests/bpf-script-example.c
+++ b/tools/perf/tests/bpf-script-example.c
@@ -46,3 +46,11 @@ int bpf_func__SyS_epoll_wait(void *ctx)
 }
 char _license[] SEC("license") = "GPL";
 int _version SEC("version") = LINUX_VERSION_CODE;
+
+#ifdef TEST_PERF_HOOK
+SEC("perfhook:test")
+void hook_test(void)
+{
+	return;
+}
+#endif
diff --git a/tools/perf/tests/clang.c b/tools/perf/tests/clang.c
index f853e24..e7b35c4 100644
--- a/tools/perf/tests/clang.c
+++ b/tools/perf/tests/clang.c
@@ -16,6 +16,10 @@ static struct {
 		.func = test__clang_to_obj,
 		.desc = "builtin clang compile C source to ELF object",
 	},
+	{
+		.func = test__clang_jit,
+		.desc = "builtin clang compile mixed BPF and native code",
+	},
 #endif
 };
 
diff --git a/tools/perf/util/c++/clang-c.h b/tools/perf/util/c++/clang-c.h
index 0eadd79..5ebcb41 100644
--- a/tools/perf/util/c++/clang-c.h
+++ b/tools/perf/util/c++/clang-c.h
@@ -14,6 +14,7 @@ extern void perf_clang__cleanup(void);
 
 extern int test__clang_to_IR(void);
 extern int test__clang_to_obj(void);
+extern int test__clang_jit(void);
 
 extern int perf_clang__compile_bpf(const char *filename,
 				   void **p_obj_buf,
@@ -26,6 +27,7 @@ static inline void perf_clang__cleanup(void) { }
 
 static inline int test__clang_to_IR(void) { return -1; }
 static inline int test__clang_to_obj(void) { return -1;}
+static inline int test__clang_jit(void) { return -1;}
 
 static inline int
 perf_clang__compile_bpf(const char *filename __maybe_unused,
diff --git a/tools/perf/util/c++/clang-test.cpp b/tools/perf/util/c++/clang-test.cpp
index fb05e56..2b4aa8d 100644
--- a/tools/perf/util/c++/clang-test.cpp
+++ b/tools/perf/util/c++/clang-test.cpp
@@ -5,6 +5,7 @@
 
 #include <util-cxx.h>
 #include <tests/llvm.h>
+#include <perf-hooks.h>
 #include <string>
 
 class perf_clang_scope {
@@ -14,7 +15,7 @@ public:
 };
 
 static std::unique_ptr<perf::PerfModule>
-__test__clang_to_IR(void)
+__test__clang_to_IR(bool perfhook)
 {
 	unsigned int kernel_version;
 
@@ -23,14 +24,22 @@ __test__clang_to_IR(void)
 
 	std::string cflag_kver("-DLINUX_VERSION_CODE=" +
 				std::to_string(kernel_version));
+	std::string cflag_perfhook(perfhook ? "-DTEST_PERF_HOOK=1" : "");
 
 	std::unique_ptr<perf::PerfModule> M =
-		perf::getModuleFromSource({cflag_kver.c_str()},
+		perf::getModuleFromSource({cflag_kver.c_str(),
+					   cflag_perfhook.c_str()},
 					  "perf-test.c",
 					  test_llvm__bpf_base_prog);
 	return M;
 }
 
+static std::unique_ptr<perf::PerfModule>
+__test__clang_to_IR(void)
+{
+	return __test__clang_to_IR(false);
+}
+
 extern "C" {
 int test__clang_to_IR(void)
 {
@@ -59,4 +68,23 @@ int test__clang_to_obj(void)
 	return 0;
 }
 
+int test__clang_jit(void)
+{
+	perf_clang_scope _scope;
+
+	auto M = __test__clang_to_IR(true);
+	if (!M)
+		return -1;
+
+	if (M->doJIT())
+		return -1;
+
+	std::unique_ptr<perf::PerfModule::HookMap> hooks(M->copyJITResult());
+	for (auto i : *hooks)
+		perf_hooks__set_hook(i.first.c_str(), i.second, NULL);
+
+	perf_hooks__invoke_test();
+	return 0;
+}
+
 }
diff --git a/tools/perf/util/c++/clang.cpp b/tools/perf/util/c++/clang.cpp
index 8a0f818..b996ec6 100644
--- a/tools/perf/util/c++/clang.cpp
+++ b/tools/perf/util/c++/clang.cpp
@@ -14,9 +14,14 @@
 #include "clang/Frontend/TextDiagnosticPrinter.h"
 #include "clang/Tooling/Tooling.h"
 #include "llvm/ADT/SmallString.h"
+#include "llvm/ExecutionEngine/Orc/CompileUtils.h"
+#include "llvm/ExecutionEngine/Orc/IRCompileLayer.h"
+#include "llvm/ExecutionEngine/Orc/LambdaResolver.h"
+#include "llvm/ExecutionEngine/Orc/ObjectLinkingLayer.h"
 #include "llvm/IR/LegacyPassManager.h"
 #include "llvm/IR/Module.h"
 #include "llvm/Option/Option.h"
+#include "llvm/Support/DynamicLibrary.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/TargetRegistry.h"
@@ -24,11 +29,13 @@
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetOptions.h"
 #include <memory>
+#include <vector>
 
 #include "clang.h"
 #include "clang-c.h"
 #include "llvm-utils.h"
 #include "util-cxx.h"
+#include "perf-hooks.h"
 
 namespace perf {
 
@@ -190,6 +197,66 @@ PerfModule::toBPFObject(void)
 	return std::move(Buffer);
 }
 
+/*
+ * Use a global memory manager so allocated code and data won't be released
+ * when object destroy.
+ */
+static llvm::SectionMemoryManager JITMemoryManager;
+
+int PerfModule::doJIT(void)
+{
+	using namespace orc;
+
+	prepareJIT();
+
+	std::unique_ptr<TargetMachine> TM(EngineBuilder().selectTarget());
+	if (!TM) {
+		llvm::errs() << "Can't get target machine\n";
+		return -1;
+	}
+	const DataLayout DL(TM->createDataLayout());
+	Module->setDataLayout(DL);
+	Module->setTargetTriple(TM->getTargetTriple().normalize());
+
+	ObjectLinkingLayer<> ObjectLayer;
+	IRCompileLayer<decltype(ObjectLayer)> CompileLayer(ObjectLayer, SimpleCompiler(*TM));
+
+	auto Resolver = createLambdaResolver(
+			[](const std::string &Name) {
+				return RuntimeDyld::SymbolInfo(nullptr);
+			},
+			[](const std::string &Name) {
+				return RuntimeDyld::SymbolInfo(nullptr);
+			});
+
+	std::vector<llvm::Module *> Ms;
+	Ms.push_back(getModule());
+	CompileLayer.addModuleSet(std::move(Ms),
+			&JITMemoryManager,
+			std::move(Resolver));
+
+
+	for (Function *F : JITFunctions) {
+		JITSymbol sym = CompileLayer.findSymbol(F->getName().str(), true);
+
+		/*
+		 * Type of F->getSection() is moving from
+		 * const char * to StringRef.
+		 * Convert it to std::string so we don't need
+		 * consider this API change.
+		 */
+		std::string sec(F->getSection());
+		std::string hook(&sec.c_str()[sizeof("perfhook:") - 1]);
+		perf_hook_func_t func = (perf_hook_func_t)(intptr_t)sym.getAddress();
+
+		if (JITResult[hook])
+			llvm::errs() << "Warning: multiple functions on hook "
+				     << hook << ", only one is used\n";
+		JITResult[hook] = func;
+	}
+	return 0;
+}
+
 class ClangOptions {
 	llvm::SmallString<PATH_MAX> FileName;
 	llvm::SmallString<64> KVerDef;
@@ -295,6 +362,10 @@ void perf_clang__init(void)
 	LLVMInitializeBPFTarget();
 	LLVMInitializeBPFTargetMC();
 	LLVMInitializeBPFAsmPrinter();
+
+	llvm::InitializeNativeTarget();
+	llvm::InitializeNativeTargetAsmPrinter();
+	llvm::InitializeNativeTargetAsmParser();
 }
 
 void perf_clang__cleanup(void)
diff --git a/tools/perf/util/c++/clang.h b/tools/perf/util/c++/clang.h
index 1eb71a6..df2eb8f 100644
--- a/tools/perf/util/c++/clang.h
+++ b/tools/perf/util/c++/clang.h
@@ -7,18 +7,26 @@
 #include "llvm/Option/Option.h"
 #include <memory>
 #include <set>
+#include <map>
+
+#include "util/perf-hooks.h"
 
 namespace perf {
 
 using namespace llvm;
 
 class PerfModule {
+public:
+	typedef std::map<std::string, perf_hook_func_t> HookMap;
 private:
 	std::unique_ptr<llvm::Module> Module;
 
 	std::set<llvm::GlobalVariable *> Maps;
 	std::set<llvm::Function *> BPFFunctions;
 	std::set<llvm::Function *> JITFunctions;
+
+	HookMap JITResult;
+
 	void prepareBPF(void);
 	void prepareJIT(void);
 public:
@@ -26,10 +34,15 @@ class PerfModule {
 	{
 		return Module.get();
 	}
+	inline HookMap *copyJITResult(void)
+	{
+		return new HookMap(JITResult);
+	}
 
 	PerfModule(std::unique_ptr<llvm::Module>&& M);
 
 	std::unique_ptr<llvm::SmallVectorImpl<char>> toBPFObject(void);
+	int doJIT(void);
 };
 
 std::unique_ptr<PerfModule>
-- 
2.10.1

[PATCH v4 09/18] perf clang jit: Export functions for jitted code

[Wang Nan]

After this patch functions attached on perf hooks is allowed to invoke
external functions. Add a testcase for this feature.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
 tools/perf/tests/Build                |  2 +-
 tools/perf/tests/bpf-script-example.c |  4 ++++
 tools/perf/util/c++/clang-c.h         |  2 ++
 tools/perf/util/c++/clang-test.cpp    |  9 +++++++++
 tools/perf/util/c++/clang.cpp         | 17 ++++++++++++++++-
 5 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/tools/perf/tests/Build b/tools/perf/tests/Build
index 6676c2d..d6e6e00 100644
--- a/tools/perf/tests/Build
+++ b/tools/perf/tests/Build
@@ -49,7 +49,7 @@ $(OUTPUT)tests/llvm-src-base.c: tests/bpf-script-example.c tests/Build
 	$(call rule_mkdir)
 	$(Q)echo '#include <tests/llvm.h>' > $@
 	$(Q)echo 'const char test_llvm__bpf_base_prog[] =' >> $@
-	$(Q)sed -e 's/"/\\"/g' -e 's/\(.*\)/"\1\\n"/g' $< >> $@
+	$(Q)sed -e 's/\\/\\\\/g' -e 's/"/\\"/g' -e 's/\(.*\)/"\1\\n"/g' $< >> $@
 	$(Q)echo ';' >> $@
 
 $(OUTPUT)tests/llvm-src-kbuild.c: tests/bpf-script-test-kbuild.c tests/Build
diff --git a/tools/perf/tests/bpf-script-example.c b/tools/perf/tests/bpf-script-example.c
index 265036e..ccbc19c 100644
--- a/tools/perf/tests/bpf-script-example.c
+++ b/tools/perf/tests/bpf-script-example.c
@@ -48,9 +48,13 @@ char _license[] SEC("license") = "GPL";
 int _version SEC("version") = LINUX_VERSION_CODE;
 
 #ifdef TEST_PERF_HOOK
+extern int printf(const char *fmt, ...);
+extern void test__clang_callback(int x);
 SEC("perfhook:test")
 void hook_test(void)
 {
+	printf("Hello, hook_test\n");
+	test__clang_callback(1234);
 	return;
 }
 #endif
diff --git a/tools/perf/util/c++/clang-c.h b/tools/perf/util/c++/clang-c.h
index 5ebcb41..9f75e41 100644
--- a/tools/perf/util/c++/clang-c.h
+++ b/tools/perf/util/c++/clang-c.h
@@ -16,6 +16,8 @@ extern int test__clang_to_IR(void);
 extern int test__clang_to_obj(void);
 extern int test__clang_jit(void);
 
+extern void test__clang_callback(int x);
+
 extern int perf_clang__compile_bpf(const char *filename,
 				   void **p_obj_buf,
 				   size_t *p_obj_buf_sz);
diff --git a/tools/perf/util/c++/clang-test.cpp b/tools/perf/util/c++/clang-test.cpp
index 2b4aa8d..0bdb807 100644
--- a/tools/perf/util/c++/clang-test.cpp
+++ b/tools/perf/util/c++/clang-test.cpp
@@ -68,6 +68,13 @@ int test__clang_to_obj(void)
 	return 0;
 }
 
+static int callback_flag;
+
+void test__clang_callback(int x)
+{
+	callback_flag = x;
+}
+
 int test__clang_jit(void)
 {
 	perf_clang_scope _scope;
@@ -84,6 +91,8 @@ int test__clang_jit(void)
 		perf_hooks__set_hook(i.first.c_str(), i.second, NULL);
 
 	perf_hooks__invoke_test();
+	if (callback_flag != 1234)
+		return -1;
 	return 0;
 }
 
diff --git a/tools/perf/util/c++/clang.cpp b/tools/perf/util/c++/clang.cpp
index b996ec6..3ce2e0e 100644
--- a/tools/perf/util/c++/clang.cpp
+++ b/tools/perf/util/c++/clang.cpp
@@ -30,6 +30,8 @@
 #include "llvm/Target/TargetOptions.h"
 #include <memory>
 #include <vector>
+#include <set>
+#include <tuple>
 
 #include "clang.h"
 #include "clang-c.h"
@@ -197,6 +199,15 @@ PerfModule::toBPFObject(void)
 	return std::move(Buffer);
 }
 
+static std::map<const std::string, const void *> exported_funcs =
+{
+#define EXPORT(f) {#f, (const void *)&f}
+	EXPORT(test__clang_callback),
+	EXPORT(printf),
+	EXPORT(puts),
+#undef EXPORT
+};
+
 /*
  * Use a global memory manager so allocated code and data won't be released
  * when object destroy.
@@ -223,7 +234,11 @@ int PerfModule::doJIT(void)
 
 	auto Resolver = createLambdaResolver(
 			[](const std::string &Name) {
-				return RuntimeDyld::SymbolInfo(nullptr);
+				auto i = exported_funcs.find(Name);
+				if (i == exported_funcs.end())
+					return RuntimeDyld::SymbolInfo(nullptr);
+				return RuntimeDyld::SymbolInfo((uint64_t)(i->second),
+							       JITSymbolFlags::Exported);
 			},
 			[](const std::string &Name) {
 				return RuntimeDyld::SymbolInfo(nullptr);
-- 
2.10.1

[PATCH v4 10/18] perf clang jit: Actually JIT and hook in bpf loader

[Wang Nan]

Makes perf_clang__compile_bpf() actually uses clang jit to compile perf
hooks. Returns a map through perf_clang__compile_bpf(), and set hooks
after bpf_object is created.

After this path jitting takes actions for bpf loader. For example:
  $ cat ./test.c
  /******************************************************/
  #define SEC(name) __attribute__((section(name), used))
  SEC("dofork=_do_fork")
  int dofork(void *ctx)
  {
      return 0;
  }
  extern int printf(const char *fmt, ...);
  SEC("perfhook:record_start")
  void record_start(void)
  {
      printf("Welcom to perf record\n");
  }
  SEC("perfhook:record_end")
  void record_end(void)
  {
      printf("Goodbye, perf record\n");
  }
  char _license[] SEC("license") = "GPL";
  int _version SEC("version") = LINUX_VERSION_CODE;
  /******************************************************/
  $ perf record -e ./test.c sleep 1
  Welcom to perf record
  [ perf record: Woken up 1 times to write data ]
  Goodbye, perf record
  [ perf record: Captured and wrote 0.014 MB perf.data ]

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
 tools/perf/util/bpf-loader.c  | 11 ++++++++++-
 tools/perf/util/c++/clang-c.h | 18 ++++++++++++++++--
 tools/perf/util/c++/clang.cpp | 28 +++++++++++++++++++++++++++-
 3 files changed, 53 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index 36c8611..bf61a6f 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -85,9 +85,11 @@ struct bpf_object *bpf__prepare_load(const char *filename, bool source)
 		int err;
 		void *obj_buf;
 		size_t obj_buf_sz;
+		jitted_funcs_map_t jitted_funcs_map;
 
 		perf_clang__init();
-		err = perf_clang__compile_bpf(filename, &obj_buf, &obj_buf_sz);
+		err = perf_clang__compile_bpf(filename, &obj_buf,
+					      &obj_buf_sz, &jitted_funcs_map);
 		perf_clang__cleanup();
 		if (err) {
 			pr_warning("bpf: builtin compilation failed: %d, try external compiler\n", err);
@@ -101,6 +103,13 @@ struct bpf_object *bpf__prepare_load(const char *filename, bool source)
 		if (!IS_ERR(obj) && llvm_param.dump_obj)
 			llvm__dump_obj(filename, obj_buf, obj_buf_sz);
 
+		/*
+		 * Call perf_clang__hook_jitted_func even IS_ERR(obj) to make sure
+		 * the C++ map pointer is deleted.
+		 */
+		if (jitted_funcs_map)
+			perf_clang__hook_jitted_func(jitted_funcs_map, obj, IS_ERR(obj));
+
 		free(obj_buf);
 	} else
 		obj = bpf_object__open(filename);
diff --git a/tools/perf/util/c++/clang-c.h b/tools/perf/util/c++/clang-c.h
index 9f75e41..021b1ad 100644
--- a/tools/perf/util/c++/clang-c.h
+++ b/tools/perf/util/c++/clang-c.h
@@ -8,6 +8,7 @@
 extern "C" {
 #endif
 
+typedef void *jitted_funcs_map_t;
 #ifdef HAVE_LIBCLANGLLVM_SUPPORT
 extern void perf_clang__init(void);
 extern void perf_clang__cleanup(void);
@@ -20,7 +21,11 @@ extern void test__clang_callback(int x);
 
 extern int perf_clang__compile_bpf(const char *filename,
 				   void **p_obj_buf,
-				   size_t *p_obj_buf_sz);
+				   size_t *p_obj_buf_sz,
+				   jitted_funcs_map_t *p_funcs_map);
+
+extern int
+perf_clang__hook_jitted_func(jitted_funcs_map_t map, void *ctx, bool is_err);
 #else
 
 
@@ -34,7 +39,16 @@ static inline int test__clang_jit(void) { return -1;}
 static inline int
 perf_clang__compile_bpf(const char *filename __maybe_unused,
 			void **p_obj_buf __maybe_unused,
-			size_t *p_obj_buf_sz __maybe_unused)
+			size_t *p_obj_buf_sz __maybe_unused,
+			jitted_funcs_map_t *p_funcs_map __maybe_unused)
+{
+	return -ENOTSUP;
+}
+
+static inline int
+perf_clang__hook_jitted_func(jitted_funcs_map_t map __maybe_unused,
+			     void *ctx __maybe_unused,
+			     bool is_err __maybe_unused)
 {
 	return -ENOTSUP;
 }
diff --git a/tools/perf/util/c++/clang.cpp b/tools/perf/util/c++/clang.cpp
index 3ce2e0e..4a98597 100644
--- a/tools/perf/util/c++/clang.cpp
+++ b/tools/perf/util/c++/clang.cpp
@@ -391,7 +391,8 @@ void perf_clang__cleanup(void)
 
 int perf_clang__compile_bpf(const char *_filename,
 			    void **p_obj_buf,
-			    size_t *p_obj_buf_sz)
+			    size_t *p_obj_buf_sz,
+			    jitted_funcs_map_t *p_funcs_map)
 {
 	using namespace perf;
 
@@ -418,6 +419,31 @@ int perf_clang__compile_bpf(const char *_filename,
 	memcpy(buffer, O->data(), size);
 	*p_obj_buf = buffer;
 	*p_obj_buf_sz = size;
+
+	if (M->doJIT())
+		return -1;
+
+	if (p_funcs_map)
+		*p_funcs_map = (jitted_funcs_map_t)(M->copyJITResult());
+	return 0;
+}
+
+int perf_clang__hook_jitted_func(jitted_funcs_map_t map, void *ctx, bool is_err)
+{
+	std::unique_ptr<perf::PerfModule::HookMap>
+		hook_map((perf::PerfModule::HookMap *)map);
+
+	/* Do nothing but ensure map is deleted */
+	if (is_err)
+		return -1;
+
+	for (auto i : *hook_map) {
+		const char *hook_name = i.first.c_str();
+		perf_hook_func_t hook_func = i.second;
+
+		if (perf_hooks__set_hook(hook_name, hook_func, ctx))
+			return -1;
+	}
 	return 0;
 }
 }
-- 
2.10.1

[PATCH v4 11/18] perf clang jit: Collect the lowest address in maps section as map_base

[Wang Nan]

During jitting, find the lowest address in maps section and store its
value to _map_base. Pass its value out through perf_clang__compile_bpf().
map_base is useful for jitted functions accessing BPF maps.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
 tools/perf/util/bpf-loader.c  | 39 +++++++++++++++++++++++++++++++++++++--
 tools/perf/util/c++/clang-c.h |  6 ++++--
 tools/perf/util/c++/clang.cpp | 15 +++++++++++++--
 tools/perf/util/c++/clang.h   |  5 +++++
 4 files changed, 59 insertions(+), 6 deletions(-)

diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index bf61a6f..9a0c33d 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -47,6 +47,10 @@ struct bpf_prog_priv {
 	int *type_mapping;
 };
 
+struct bpf_obj_priv {
+	void *map_base;
+};
+
 static bool libbpf_initialized;
 
 struct bpf_object *
@@ -70,9 +74,20 @@ bpf__prepare_load_buffer(void *obj_buf, size_t obj_buf_sz, const char *name)
 	return obj;
 }
 
+static void
+clear_obj_priv(struct bpf_object *obj __maybe_unused,
+	       void *_priv)
+{
+	struct bpf_obj_priv *priv = _priv;
+
+	free(priv);
+}
+
 struct bpf_object *bpf__prepare_load(const char *filename, bool source)
 {
 	struct bpf_object *obj;
+	void *map_base = NULL;
+	int err;
 
 	if (!libbpf_initialized) {
 		libbpf_set_print(libbpf_warning,
@@ -82,14 +97,14 @@ struct bpf_object *bpf__prepare_load(const char *filename, bool source)
 	}
 
 	if (source) {
-		int err;
 		void *obj_buf;
 		size_t obj_buf_sz;
 		jitted_funcs_map_t jitted_funcs_map;
 
 		perf_clang__init();
 		err = perf_clang__compile_bpf(filename, &obj_buf,
-					      &obj_buf_sz, &jitted_funcs_map);
+					      &obj_buf_sz, &jitted_funcs_map,
+					      &map_base);
 		perf_clang__cleanup();
 		if (err) {
 			pr_warning("bpf: builtin compilation failed: %d, try external compiler\n", err);
@@ -119,7 +134,27 @@ struct bpf_object *bpf__prepare_load(const char *filename, bool source)
 		return obj;
 	}
 
+	if (map_base) {
+		struct bpf_obj_priv *priv = calloc(sizeof(*priv), 1);
+
+		if (!priv) {
+			pr_debug("bpf: failed to alloc priv for object\n");
+			err = -ENOMEM;
+			goto errout;
+		}
+		priv->map_base = map_base;
+
+		err = bpf_object__set_priv(obj, priv, clear_obj_priv);
+		if (err) {
+			pr_debug("Failed to set priv for object '%s'\n", filename);
+			goto errout;
+		}
+	}
+
 	return obj;
+errout:
+	bpf_object__close(obj);
+	return ERR_PTR(err);
 }
 
 void bpf__clear(void)
diff --git a/tools/perf/util/c++/clang-c.h b/tools/perf/util/c++/clang-c.h
index 021b1ad..4cf651b 100644
--- a/tools/perf/util/c++/clang-c.h
+++ b/tools/perf/util/c++/clang-c.h
@@ -22,7 +22,8 @@ extern void test__clang_callback(int x);
 extern int perf_clang__compile_bpf(const char *filename,
 				   void **p_obj_buf,
 				   size_t *p_obj_buf_sz,
-				   jitted_funcs_map_t *p_funcs_map);
+				   jitted_funcs_map_t *p_funcs_map,
+				   void **p_map_base);
 
 extern int
 perf_clang__hook_jitted_func(jitted_funcs_map_t map, void *ctx, bool is_err);
@@ -40,7 +41,8 @@ static inline int
 perf_clang__compile_bpf(const char *filename __maybe_unused,
 			void **p_obj_buf __maybe_unused,
 			size_t *p_obj_buf_sz __maybe_unused,
-			jitted_funcs_map_t *p_funcs_map __maybe_unused)
+			jitted_funcs_map_t *p_funcs_map __maybe_unused,
+			void **p_map_base __maybe_unused)
 {
 	return -ENOTSUP;
 }
diff --git a/tools/perf/util/c++/clang.cpp b/tools/perf/util/c++/clang.cpp
index 4a98597..684855c 100644
--- a/tools/perf/util/c++/clang.cpp
+++ b/tools/perf/util/c++/clang.cpp
@@ -119,7 +119,7 @@ getModuleFromSource(llvm::opt::ArgStringList CFlags, StringRef Path)
 	return getModuleFromSource(std::move(CFlags), Path, VFS);
 }
 
-PerfModule::PerfModule(std::unique_ptr<llvm::Module>&& M) : Module(std::move(M))
+PerfModule::PerfModule(std::unique_ptr<llvm::Module>&& M) : Module(std::move(M)), _map_base(NULL)
 {
 	for (llvm::Function& F : *Module) {
 		if (F.getLinkage() != llvm::GlobalValue::ExternalLinkage)
@@ -250,6 +250,13 @@ int PerfModule::doJIT(void)
 			&JITMemoryManager,
 			std::move(Resolver));
 
+	void *map_base = NULL;
+	for (llvm::GlobalValue *map : Maps) {
+		JITSymbol sym = CompileLayer.findSymbol(map->getName().str(), true);
+		void *address = (void *)(intptr_t)sym.getAddress();
+		if (!map_base || address < map_base)
+			map_base = address;
+	}
 
 	for (Function *F : JITFunctions) {
 		JITSymbol sym = CompileLayer.findSymbol(F->getName().str(), true);
@@ -269,6 +276,7 @@ int PerfModule::doJIT(void)
 				     << hook << ", only one is used\n";
 		JITResult[hook] = func;
 	}
+	_map_base = map_base;
 	return 0;
 }
 
@@ -392,7 +400,8 @@ void perf_clang__cleanup(void)
 int perf_clang__compile_bpf(const char *_filename,
 			    void **p_obj_buf,
 			    size_t *p_obj_buf_sz,
-			    jitted_funcs_map_t *p_funcs_map)
+			    jitted_funcs_map_t *p_funcs_map,
+			    void **p_map_base)
 {
 	using namespace perf;
 
@@ -425,6 +434,8 @@ int perf_clang__compile_bpf(const char *_filename,
 
 	if (p_funcs_map)
 		*p_funcs_map = (jitted_funcs_map_t)(M->copyJITResult());
+	if (p_map_base)
+		*p_map_base = M->getMapBase();
 	return 0;
 }
 
diff --git a/tools/perf/util/c++/clang.h b/tools/perf/util/c++/clang.h
index df2eb8f..aacedc2 100644
--- a/tools/perf/util/c++/clang.h
+++ b/tools/perf/util/c++/clang.h
@@ -26,6 +26,7 @@ class PerfModule {
 	std::set<llvm::Function *> JITFunctions;
 
 	HookMap JITResult;
+	void *_map_base;
 
 	void prepareBPF(void);
 	void prepareJIT(void);
@@ -38,6 +39,10 @@ class PerfModule {
 	{
 		return new HookMap(JITResult);
 	}
+	inline void *getMapBase(void)
+	{
+		return _map_base;
+	}
 
 	PerfModule(std::unique_ptr<llvm::Module>&& M);
 
-- 
2.10.1

[PATCH v4 12/18] perf clang jit: Retrive fd of BPF map from its offset

[Wang Nan]

bpf__map_fd() is introduced to retrive fd of a BPF map through its
offset in BPF object. This function is going be used in further
commits which allow scripts jitted by builtin clang access BPF maps.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
 tools/perf/util/bpf-loader.c | 37 +++++++++++++++++++++++++++++++++++++
 tools/perf/util/bpf-loader.h | 19 +++++++++++++++++++
 2 files changed, 56 insertions(+)

diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index 9a0c33d..3eb420e 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -19,6 +19,7 @@
 #include "parse-events.h"
 #include "llvm-utils.h"
 #include "c++/clang-c.h"
+#include "asm/bug.h"	// for WARN_ONCE
 
 #define DEFINE_PRINT_FN(name, level) \
 static int libbpf_##name(const char *fmt, ...)	\
@@ -1644,6 +1645,28 @@ int bpf__setup_stdout(struct perf_evlist *evlist __maybe_unused)
 	return 0;
 }
 
+int bpf__map_fd(struct bpf_object *obj, void *jit_map)
+{
+	struct bpf_obj_priv *priv = bpf_object__priv(obj);
+	struct bpf_map *map;
+	size_t map_offset;
+	void *map_base;
+
+	if (IS_ERR(priv))
+		return PTR_ERR(priv);
+	if (!priv)
+		return -EINVAL;
+
+	map_base = priv->map_base;
+	map_offset = jit_map - map_base;
+	map = bpf_object__find_map_by_offset(obj, map_offset);
+	WARN_ONCE(IS_ERR(map), "can't find map offset %zu from '%s'\n",
+		  map_offset, bpf_object__name(obj));
+	if (IS_ERR(map))
+		return -ENOENT;
+	return bpf_map__fd(map);
+}
+
 #define ERRNO_OFFSET(e)		((e) - __BPF_LOADER_ERRNO__START)
 #define ERRCODE_OFFSET(c)	ERRNO_OFFSET(BPF_LOADER_ERRNO__##c)
 #define NR_ERRNO	(__BPF_LOADER_ERRNO__END - __BPF_LOADER_ERRNO__START)
@@ -1825,3 +1848,17 @@ int bpf__strerror_setup_stdout(struct perf_evlist *evlist __maybe_unused,
 	bpf__strerror_end(buf, size);
 	return 0;
 }
+
+int bpf__strerror_map_fd(struct bpf_object *obj, void *jit_map,
+			 int err, char *buf, size_t size)
+{
+	struct bpf_obj_priv *priv = bpf_object__priv(obj);
+	ptrdiff_t offset = priv ? jit_map - priv->map_base : jit_map - NULL;
+
+	bpf__strerror_head(err, buf, size);
+	bpf__strerror_entry(EINVAL, "No map in BPF object %s", bpf_object__name(obj));
+	bpf__strerror_entry(ENOENT, "Can't find map offset %lx in BPF object %s",
+			    (unsigned long)offset, bpf_object__name(obj));
+	bpf__strerror_end(buf, size);
+	return 0;
+}
diff --git a/tools/perf/util/bpf-loader.h b/tools/perf/util/bpf-loader.h
index f2b737b..c40812b 100644
--- a/tools/perf/util/bpf-loader.h
+++ b/tools/perf/util/bpf-loader.h
@@ -84,6 +84,9 @@ int bpf__setup_stdout(struct perf_evlist *evlist);
 int bpf__strerror_setup_stdout(struct perf_evlist *evlist, int err,
 			       char *buf, size_t size);
 
+int bpf__map_fd(struct bpf_object *obj, void *jit_map);
+int bpf__strerror_map_fd(struct bpf_object *obj, void *jit_map,
+			 int err, char *buf, size_t size);
 #else
 static inline struct bpf_object *
 bpf__prepare_load(const char *filename __maybe_unused,
@@ -136,6 +139,13 @@ bpf__setup_stdout(struct perf_evlist *evlist __maybe_unused)
 }
 
 static inline int
+bpf__map_fd(struct bpf_object *obj __maybe_unused,
+	    void *map_ptr __maybe_unused)
+{
+	return -ENOTSUP;
+}
+
+static inline int
 __bpf_strerror(char *buf, size_t size)
 {
 	if (!size)
@@ -196,5 +206,14 @@ bpf__strerror_setup_stdout(struct perf_evlist *evlist __maybe_unused,
 {
 	return __bpf_strerror(buf, size);
 }
+
+static inline int
+bpf__strerror_map_fd(struct bpf_object *obj __maybe_unused,
+		     void *jit_map __maybe_unused,
+		     int err __maybe_unused,
+		     char *buf, size_t size);
+{
+	return __bpf_strerror(buf, size);
+}
 #endif
 #endif
-- 
2.10.1

[PATCH v4 13/18] perf clang jit: Allow jitted perf hook access BPF maps

[Wang Nan]

Newly introduced jit-helpers.[ch] defines a series of helpers which helps
jitted perf hook functions accessing BPF maps defined in their BPF scripts.
The helpers fetches fd of 'struct bpf_map' from 'struct bpf_object' and the
address of 'struct bpf_map_def' in jitted file. 'struct bpf_object' is the
context passed to hooks.

Jit helpers added in this commits are all leading with 'perf_'. We don't use
'bpf_' prefix because in following commits 'bpf_' prefix is going to be assigned
to kernel side BPF map operations. Same operation has different protocol for
kernel and user.

 Example:

  $ cat ./test.c
  /*******************************************************/
  #define SEC(name) __attribute__((section(name), used))
  #define BPF_MAP_TYPE_ARRAY 2
  #define BPF_MAP_TYPE_PERF_EVENT_ARRAY 4
  #define BPF_FUNC_map_lookup_elem 1
  static void *(*bpf_map_lookup_elem)(void *map, void *key) =
      (void *) BPF_FUNC_map_lookup_elem;
  struct bpf_map_def {
      unsigned int type;
      unsigned int key_size;
      unsigned int value_size;
      unsigned int max_entries;
  };
  struct bpf_map_def SEC("maps") counter = {
      .type = BPF_MAP_TYPE_ARRAY,
      .key_size = sizeof(int),
      .value_size = sizeof(int),
      .max_entries = 1,
  };
  extern int perf_map_update_elem(void *ctx, struct bpf_map_def *map,
                         void *key, void *value, unsigned long flags);
  extern int perf_map_lookup_elem(void *ctx, struct bpf_map_def *map,
                         void *key, void *value);
  SEC("sys_close=SyS_close")
  int sys_close(void *ctx)
  {
      int key = 0;
      int *value;
      value = bpf_map_lookup_elem(&counter, &key);
      if (!value)
          return 0;
      __sync_fetch_and_add(value, 1);
      return 0;
  }
  extern int printf(const char *fmt, ...);
  SEC("perfhook:record_start")
  void record_start(void *ctx)
  {
      int key = 0;
      int value = 100000000;
      printf("Welcom to perf record\n");
      perf_map_update_elem(ctx, &counter, &key, &value, 0);
  }

  SEC("perfhook:record_end")
  void record_end(void *ctx)
  {
      int key = 0;
      int value;
      perf_map_lookup_elem(ctx, &counter, &key, &value);
      printf("Goodbye, perf record, value=%d\n", value);
  }
  char _license[] SEC("license") = "GPL";
  int _version SEC("version") = LINUX_VERSION_CODE;
  /*******************************************************/
  $ sudo perf record  -e ./test.c echo Hehe
  Welcom to perf record
  Hehe
  [ perf record: Woken up 1 times to write data ]
  Goodbye, perf record, value=100000644
  [ perf record: Captured and wrote 0.014 MB perf.data ]

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Alexei Starovoitov <ast@fb.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
 tools/perf/util/Build         |  1 +
 tools/perf/util/c++/clang.cpp |  9 ++++++-
 tools/perf/util/jit-helpers.c | 57 +++++++++++++++++++++++++++++++++++++++++++
 tools/perf/util/jit-helpers.h | 28 +++++++++++++++++++++
 4 files changed, 94 insertions(+), 1 deletion(-)
 create mode 100644 tools/perf/util/jit-helpers.c
 create mode 100644 tools/perf/util/jit-helpers.h

diff --git a/tools/perf/util/Build b/tools/perf/util/Build
index 3840e3a..e42ae4f 100644
--- a/tools/perf/util/Build
+++ b/tools/perf/util/Build
@@ -125,6 +125,7 @@ libperf-$(CONFIG_DWARF) += genelf_debug.o
 endif
 
 libperf-y += perf-hooks.o
+libperf-y += jit-helpers.o
 
 libperf-$(CONFIG_CXX) += c++/
 
diff --git a/tools/perf/util/c++/clang.cpp b/tools/perf/util/c++/clang.cpp
index 684855c..1bd92ea 100644
--- a/tools/perf/util/c++/clang.cpp
+++ b/tools/perf/util/c++/clang.cpp
@@ -38,6 +38,7 @@
 #include "llvm-utils.h"
 #include "util-cxx.h"
 #include "perf-hooks.h"
+#include "jit-helpers.h"
 
 namespace perf {
 
@@ -199,12 +200,18 @@ PerfModule::toBPFObject(void)
 	return std::move(Buffer);
 }
 
+#define __stringify_1(x)	#x
+#define __stringify(x)		__stringify_1(x)
 static std::map<const std::string, const void *> exported_funcs =
 {
-#define EXPORT(f) {#f, (const void *)&f}
+#define EXPORT(f) {__stringify(f), (const void *)&f}
 	EXPORT(test__clang_callback),
 	EXPORT(printf),
 	EXPORT(puts),
+	EXPORT(JIT_HELPER_FUNC_NAME(map_update_elem)),
+	EXPORT(JIT_HELPER_FUNC_NAME(map_lookup_elem)),
+	EXPORT(JIT_HELPER_FUNC_NAME(map_get_next_key)),
+	EXPORT(JIT_HELPER_FUNC_NAME(map_pin)),
 #undef EXPORT
 };
 
diff --git a/tools/perf/util/jit-helpers.c b/tools/perf/util/jit-helpers.c
new file mode 100644
index 0000000..1a37a20
--- /dev/null
+++ b/tools/perf/util/jit-helpers.c
@@ -0,0 +1,57 @@
+/*
+ * jit-helper.c
+ *
+ * Copyright (C) 2016 Wang Nan <wangnan0@huawei.com>
+ * Copyright (C) 2016 Huawei Inc.
+ *
+ * Provide helpers which can be invoked by jit scripts attached to
+ * perf hooks.
+ */
+
+#include <util/jit-helpers.h>
+#include <util/bpf-loader.h>
+#include <bpf/libbpf.h>
+#include <bpf/bpf.h>
+
+#include "asm/bug.h"
+
+static int get_bpf_map_fd(struct bpf_object *obj, void *map)
+{
+	int fd;
+	char errbuf[BUFSIZ];
+
+	fd = bpf__map_fd(obj, map);
+	if (fd < 0) {
+		bpf__strerror_map_fd(obj, map, fd, errbuf, sizeof(errbuf));
+		WARN_ONCE(fd < 0, "Failed to get map fd: %s\n", errbuf);
+	}
+	return fd;
+}
+
+#define PARAMS(args...) args
+#define DEFINE_JIT_BPF_MAP_HELPER(name, proto, args)			\
+	JIT_BPF_MAP_HELPER(name, proto) {				\
+		int map_fd = get_bpf_map_fd(ctx, map);			\
+									\
+		if (map_fd < 0)						\
+			return map_fd;					\
+		return bpf_map_##name(map_fd, args);			\
+	}
+
+DEFINE_JIT_BPF_MAP_HELPER(update_elem,
+			  PARAMS(void *key, void *value, u64 flags),
+			  PARAMS(key, value, flags))
+
+DEFINE_JIT_BPF_MAP_HELPER(lookup_elem,
+			  PARAMS(void *key, void *value),
+			  PARAMS(key, value))
+
+DEFINE_JIT_BPF_MAP_HELPER(get_next_key,
+			  PARAMS(void *key, void *next_key),
+			  PARAMS(key, next_key))
+
+#define bpf_map_pin bpf_obj_pin
+DEFINE_JIT_BPF_MAP_HELPER(pin,
+			  PARAMS(const char *pathname),
+			  PARAMS(pathname));
+#undef bpf_map_pin
diff --git a/tools/perf/util/jit-helpers.h b/tools/perf/util/jit-helpers.h
new file mode 100644
index 0000000..b1f7479
--- /dev/null
+++ b/tools/perf/util/jit-helpers.h
@@ -0,0 +1,28 @@
+#ifndef JIT_HELPERS_H
+#define JIT_HELPERS_H
+
+#include <stdint.h>
+#include <util/perf-hooks.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define JIT_HELPER_FUNC_NAME(name) perf_##name
+
+#define JIT_HELPER(type, name, ...) \
+type JIT_HELPER_FUNC_NAME(name)(__VA_ARGS__)
+
+#define JIT_BPF_MAP_HELPER(name, ...) \
+	JIT_HELPER(int, map_##name, void *ctx, void *map, ##__VA_ARGS__)
+
+extern JIT_BPF_MAP_HELPER(update_elem, void *key, void *value, uint64_t flags);
+extern JIT_BPF_MAP_HELPER(lookup_elem, void *key, void *value);
+extern JIT_BPF_MAP_HELPER(get_next_key, void *key, void *next_key);
+extern JIT_BPF_MAP_HELPER(pin, const char *pathname);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
-- 
2.10.1

[PATCH v4 14/18] perf clang: Link BPF functions declaration into perf

[Wang Nan]

Hardcode BPF functions declarations. Following commits will utilizes
clang's virtual file system to automatically include this header to
all BPF scripts.

The generated header is wrapped by a BUILTIN_CLANG_NO_DEFAULT_INCLUDE.
This macro will be used by following commits to allow user disable this
feature.

The C string looks ugly and heavily uses magic numbers because the
header is designed to be included automatically at very first, makes
any dependency or potential conflict harmful. Actually it is
automatically generated using a script:
https://patchwork.kernel.org/patch/9350221
However, that script is fragile so not included by this commit.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
 tools/perf/util/c++/Build                |  1 +
 tools/perf/util/c++/bpf-funcs-str.c      | 49 ++++++++++++++++++++++++++++++++
 tools/perf/util/c++/clang-bpf-includes.h | 12 ++++++++
 3 files changed, 62 insertions(+)
 create mode 100644 tools/perf/util/c++/bpf-funcs-str.c
 create mode 100644 tools/perf/util/c++/clang-bpf-includes.h

diff --git a/tools/perf/util/c++/Build b/tools/perf/util/c++/Build
index 988fef1..bd71abf 100644
--- a/tools/perf/util/c++/Build
+++ b/tools/perf/util/c++/Build
@@ -1,2 +1,3 @@
 libperf-$(CONFIG_CLANGLLVM) += clang.o
 libperf-$(CONFIG_CLANGLLVM) += clang-test.o
+libperf-$(CONFIG_CLANGLLVM) += bpf-funcs-str.o
diff --git a/tools/perf/util/c++/bpf-funcs-str.c b/tools/perf/util/c++/bpf-funcs-str.c
new file mode 100644
index 0000000..ab1a0e3
--- /dev/null
+++ b/tools/perf/util/c++/bpf-funcs-str.c
@@ -0,0 +1,49 @@
+#include "clang-bpf-includes.h"
+const char clang_builtin_bpf_funcs_str[] =
+"#ifdef BUILTIN_CLANG_DEFAULT_INCLUDE\n"
+"#ifndef BPF_FUNCS_DEFINED\n"
+"#define BPF_FUNCS_DEFINED\n"
+"static void *(*bpf_map_lookup_elem)(void *, void *) = (void *)1;\n"
+"static long (*bpf_map_update_elem)(void *, void *, void *, unsigned long) = (void *)2;\n"
+"static long (*bpf_map_delete_elem)(void *, void *) = (void *)3;\n"
+"static long (*bpf_probe_read)(void *, unsigned long, unsigned long) = (void *)4;\n"
+"static long (*bpf_ktime_get_ns)(void) = (void *)5;\n"
+"static long (*bpf_trace_printk)(void *, unsigned long, ...) = (void *)6;\n"
+"static long (*bpf_get_prandom_u32)(void) = (void *)7;\n"
+"static long (*bpf_get_smp_processor_id)(void) = (void *)8;\n"
+"static long (*bpf_skb_store_bytes)(void *, unsigned long, void *, unsigned long, unsigned long) = (void *)9;\n"
+"static long (*bpf_l3_csum_replace)(void *, unsigned long, unsigned long, unsigned long, unsigned long) = (void *)10;\n"
+"static long (*bpf_l4_csum_replace)(void *, unsigned long, unsigned long, unsigned long, unsigned long) = (void *)11;\n"
+"static void (*bpf_tail_call)(void *, void *, unsigned long) = (void *)12;\n"
+"static long (*bpf_clone_redirect)(void *, unsigned long, unsigned long) = (void *)13;\n"
+"static long (*bpf_get_current_pid_tgid)(void) = (void *)14;\n"
+"static long (*bpf_get_current_uid_gid)(void) = (void *)15;\n"
+"static long (*bpf_get_current_comm)(void *, unsigned long) = (void *)16;\n"
+"static long (*bpf_get_cgroup_classid)(void *) = (void *)17;\n"
+"static long (*bpf_skb_vlan_push)(void *, unsigned long, unsigned long) = (void *)18;\n"
+"static long (*bpf_skb_vlan_pop)(void *) = (void *)19;\n"
+"static long (*bpf_skb_get_tunnel_key)(void *, void *, unsigned long, unsigned long) = (void *)20;\n"
+"static long (*bpf_skb_set_tunnel_key)(void *, void *, unsigned long, unsigned long) = (void *)21;\n"
+"static long (*bpf_perf_event_read)(void *, unsigned long) = (void *)22;\n"
+"static long (*bpf_redirect)(unsigned long, unsigned long) = (void *)23;\n"
+"static long (*bpf_get_route_realm)(void *) = (void *)24;\n"
+"static long (*bpf_perf_event_output)(void *, void *, unsigned long, void *, unsigned long) = (void *)25;\n"
+"static long (*bpf_skb_load_bytes)(void *, unsigned long, void *, unsigned long) = (void *)26;\n"
+"static long (*bpf_get_stackid)(void *, void *, unsigned long) = (void *)27;\n"
+"static long (*bpf_csum_diff)(void *, unsigned long, void *, unsigned long, unsigned long) = (void *)28;\n"
+"static long (*bpf_skb_get_tunnel_opt)(void *, void *, unsigned long) = (void *)29;\n"
+"static long (*bpf_skb_set_tunnel_opt)(void *, void *, unsigned long) = (void *)30;\n"
+"static long (*bpf_skb_change_proto)(void *, unsigned long, unsigned long) = (void *)31;\n"
+"static long (*bpf_skb_change_type)(void *, unsigned long) = (void *)32;\n"
+"static long (*bpf_skb_under_cgroup)(void *, void *, unsigned long) = (void *)33;\n"
+"static long (*bpf_get_hash_recalc)(void *) = (void *)34;\n"
+"static long (*bpf_get_current_task)(void) = (void *)35;\n"
+"static long (*bpf_probe_write_user)(unsigned long, void *, unsigned long) = (void *)36;\n"
+"static long (*bpf_current_task_under_cgroup)(void *, unsigned long) = (void *)37;\n"
+"static long (*bpf_skb_change_tail)(void *, unsigned long, unsigned long) = (void *)38;\n"
+"static long (*bpf_skb_pull_data)(void *, unsigned long) = (void *)39;\n"
+"static long (*bpf_csum_update)(void *, unsigned long) = (void *)40;\n"
+"static long (*bpf_set_hash_invalid)(void *) = (void *)41;\n"
+"#endif\n"
+"#endif\n"
+;
diff --git a/tools/perf/util/c++/clang-bpf-includes.h b/tools/perf/util/c++/clang-bpf-includes.h
new file mode 100644
index 0000000..385a5bb
--- /dev/null
+++ b/tools/perf/util/c++/clang-bpf-includes.h
@@ -0,0 +1,12 @@
+#ifndef CLANG_BPF_INCLUDS_H
+#define CLANG_BPF_INCLUDS_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern const char clang_builtin_bpf_funcs_str[];
+
+#ifdef __cplusplus
+}
+#endif
+#endif
-- 
2.10.1

[PATCH v4 15/18] perf clang: Declare BPF functions for BPF scripts automatically

[Wang Nan]

Use Clang's OverlayFileSystem, add '-include' options to make builtin
clang define BPF functions. After this patch BPF script writer needn't
define BPF functions by their own.

Add -DBUILTIN_CLANG_DEFAULT_INCLUDE to builtin clang so when adopting
builtin clang BPF functions can be automatically defined, and keep
undefined when using external clang. Passing a
-UBUILTIN_CLANG_DEFAULT_INCLUDE to cancel this defaudefinition.

Test cases are updated to avoid redefinition of these functions.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
 tools/perf/tests/bpf-script-example.c         | 18 +++++++++------
 tools/perf/tests/bpf-script-test-prologue.c   |  2 ++
 tools/perf/tests/bpf-script-test-relocation.c | 18 +++++++++------
 tools/perf/util/c++/clang.cpp                 | 33 ++++++++++++++++++++++++++-
 4 files changed, 56 insertions(+), 15 deletions(-)

diff --git a/tools/perf/tests/bpf-script-example.c b/tools/perf/tests/bpf-script-example.c
index ccbc19c..42dc341 100644
--- a/tools/perf/tests/bpf-script-example.c
+++ b/tools/perf/tests/bpf-script-example.c
@@ -8,13 +8,6 @@
 #endif
 #define BPF_ANY 0
 #define BPF_MAP_TYPE_ARRAY 2
-#define BPF_FUNC_map_lookup_elem 1
-#define BPF_FUNC_map_update_elem 2
-
-static void *(*bpf_map_lookup_elem)(void *map, void *key) =
-	(void *) BPF_FUNC_map_lookup_elem;
-static void *(*bpf_map_update_elem)(void *map, void *key, void *value, int flags) =
-	(void *) BPF_FUNC_map_update_elem;
 
 struct bpf_map_def {
 	unsigned int type;
@@ -24,6 +17,17 @@ struct bpf_map_def {
 };
 
 #define SEC(NAME) __attribute__((section(NAME), used))
+
+#ifndef BUILTIN_CLANG_DEFAULT_INCLUDE
+#define BPF_FUNC_map_lookup_elem 1
+#define BPF_FUNC_map_update_elem 2
+
+static void *(*bpf_map_lookup_elem)(void *map, void *key) =
+	(void *) BPF_FUNC_map_lookup_elem;
+static void *(*bpf_map_update_elem)(void *map, void *key, void *value, int flags) =
+	(void *) BPF_FUNC_map_update_elem;
+#endif
+
 struct bpf_map_def SEC("maps") flip_table = {
 	.type = BPF_MAP_TYPE_ARRAY,
 	.key_size = sizeof(int),
diff --git a/tools/perf/tests/bpf-script-test-prologue.c b/tools/perf/tests/bpf-script-test-prologue.c
index 7230e62..ada812b 100644
--- a/tools/perf/tests/bpf-script-test-prologue.c
+++ b/tools/perf/tests/bpf-script-test-prologue.c
@@ -13,8 +13,10 @@
 #define FMODE_READ		0x1
 #define FMODE_WRITE		0x2
 
+#ifndef BUILTIN_CLANG_DEFAULT_INCLUDE
 static void (*bpf_trace_printk)(const char *fmt, int fmt_size, ...) =
 	(void *) 6;
+#endif
 
 SEC("func=null_lseek file->f_mode offset orig")
 int bpf_func__null_lseek(void *ctx, int err, unsigned long f_mode,
diff --git a/tools/perf/tests/bpf-script-test-relocation.c b/tools/perf/tests/bpf-script-test-relocation.c
index 93af774..57c96a3 100644
--- a/tools/perf/tests/bpf-script-test-relocation.c
+++ b/tools/perf/tests/bpf-script-test-relocation.c
@@ -8,13 +8,6 @@
 #endif
 #define BPF_ANY 0
 #define BPF_MAP_TYPE_ARRAY 2
-#define BPF_FUNC_map_lookup_elem 1
-#define BPF_FUNC_map_update_elem 2
-
-static void *(*bpf_map_lookup_elem)(void *map, void *key) =
-	(void *) BPF_FUNC_map_lookup_elem;
-static void *(*bpf_map_update_elem)(void *map, void *key, void *value, int flags) =
-	(void *) BPF_FUNC_map_update_elem;
 
 struct bpf_map_def {
 	unsigned int type;
@@ -24,6 +17,17 @@ struct bpf_map_def {
 };
 
 #define SEC(NAME) __attribute__((section(NAME), used))
+
+#ifndef BUILTIN_CLANG_DEFAULT_INCLUDE
+#define BPF_FUNC_map_lookup_elem 1
+#define BPF_FUNC_map_update_elem 2
+
+static void *(*bpf_map_lookup_elem)(void *map, void *key) =
+	(void *) BPF_FUNC_map_lookup_elem;
+static void *(*bpf_map_update_elem)(void *map, void *key, void *value, int flags) =
+	(void *) BPF_FUNC_map_update_elem;
+#endif
+
 struct bpf_map_def SEC("maps") my_table = {
 	.type = BPF_MAP_TYPE_ARRAY,
 	.key_size = sizeof(int),
diff --git a/tools/perf/util/c++/clang.cpp b/tools/perf/util/c++/clang.cpp
index 1bd92ea..feb69ea 100644
--- a/tools/perf/util/c++/clang.cpp
+++ b/tools/perf/util/c++/clang.cpp
@@ -39,9 +39,17 @@
 #include "util-cxx.h"
 #include "perf-hooks.h"
 #include "jit-helpers.h"
+#include "clang-bpf-includes.h"
 
 namespace perf {
 
+static struct BPFHeader {
+	llvm::StringRef Path;
+	llvm::StringRef Content;
+} BPFHeaders[] = {
+	{"/virtual/bpf-funcs.h", clang_builtin_bpf_funcs_str},
+};
+
 static std::unique_ptr<llvm::LLVMContext> LLVMCtx;
 
 using namespace clang;
@@ -63,6 +71,11 @@ createCompilerInvocation(llvm::opt::ArgStringList CFlags, StringRef& Path,
 		"-x", "c"};
 
 	CCArgs.append(CFlags.begin(), CFlags.end());
+	for (BPFHeader &h : BPFHeaders) {
+		CCArgs.append(1, "-include");
+		CCArgs.append(1, h.Path.begin());
+	}
+
 	CompilerInvocation *CI = tooling::newInvocation(&Diags, CCArgs);
 
 	FrontendOptions& Opts = CI->getFrontendOpts();
@@ -71,6 +84,22 @@ createCompilerInvocation(llvm::opt::ArgStringList CFlags, StringRef& Path,
 	return CI;
 }
 
+static IntrusiveRefCntPtr<vfs::FileSystem>
+addBPFHeaders(IntrusiveRefCntPtr<vfs::FileSystem> VFS)
+{
+	using namespace vfs;
+
+	llvm::IntrusiveRefCntPtr<OverlayFileSystem> OverlayFS(
+			new OverlayFileSystem(VFS));
+	llvm::IntrusiveRefCntPtr<InMemoryFileSystem> MemFS(
+			new InMemoryFileSystem(true));
+	OverlayFS->pushOverlay(MemFS);
+
+	for (BPFHeader &h : BPFHeaders)
+		MemFS->addFile(h.Path, 0, llvm::MemoryBuffer::getMemBuffer(h.Content));
+	return OverlayFS;
+}
+
 static std::unique_ptr<PerfModule>
 getModuleFromSource(llvm::opt::ArgStringList CFlags,
 		    StringRef Path, IntrusiveRefCntPtr<vfs::FileSystem> VFS)
@@ -78,7 +107,8 @@ getModuleFromSource(llvm::opt::ArgStringList CFlags,
 	CompilerInstance Clang;
 	Clang.createDiagnostics();
 
-	Clang.setVirtualFileSystem(&*VFS);
+	IntrusiveRefCntPtr<vfs::FileSystem> OverlayVFS = addBPFHeaders(VFS);
+	Clang.setVirtualFileSystem(&*OverlayVFS);
 
 	IntrusiveRefCntPtr<CompilerInvocation> CI =
 		createCompilerInvocation(std::move(CFlags), Path,
@@ -366,6 +396,7 @@ public:
 	{
 		CFlags.push_back(KVerDef.c_str());
 		CFlags.push_back(NRCpusDef.c_str());
+		CFlags.push_back("-DBUILTIN_CLANG_DEFAULT_INCLUDE");
 
 		fillCFlagsFromString(CFlags, clang_opt);
 		fillCFlagsFromString(CFlags, kbuild_include_opts, true);
-- 
2.10.1

[PATCH v4 16/18] perf clang: Include helpers to BPF scripts

[Wang Nan]

Automatically include some commonly used macros and struct definitions
into BPF scripts. Script writers are no longer required to define
'SEC' and 'struct bpf_map_def' in each of their scripts.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
 tools/perf/tests/bpf-script-example.c         |  2 +-
 tools/perf/tests/bpf-script-test-kbuild.c     |  2 ++
 tools/perf/tests/bpf-script-test-prologue.c   |  4 +++-
 tools/perf/tests/bpf-script-test-relocation.c |  3 +--
 tools/perf/util/c++/Build                     |  1 +
 tools/perf/util/c++/bpf-helper-str.c          | 15 +++++++++++++++
 tools/perf/util/c++/clang-bpf-includes.h      |  1 +
 tools/perf/util/c++/clang.cpp                 |  1 +
 8 files changed, 25 insertions(+), 4 deletions(-)
 create mode 100644 tools/perf/util/c++/bpf-helper-str.c

diff --git a/tools/perf/tests/bpf-script-example.c b/tools/perf/tests/bpf-script-example.c
index 42dc341..e60bebf 100644
--- a/tools/perf/tests/bpf-script-example.c
+++ b/tools/perf/tests/bpf-script-example.c
@@ -9,6 +9,7 @@
 #define BPF_ANY 0
 #define BPF_MAP_TYPE_ARRAY 2
 
+#ifndef BUILTIN_CLANG_DEFAULT_INCLUDE
 struct bpf_map_def {
 	unsigned int type;
 	unsigned int key_size;
@@ -18,7 +19,6 @@ struct bpf_map_def {
 
 #define SEC(NAME) __attribute__((section(NAME), used))
 
-#ifndef BUILTIN_CLANG_DEFAULT_INCLUDE
 #define BPF_FUNC_map_lookup_elem 1
 #define BPF_FUNC_map_update_elem 2
 
diff --git a/tools/perf/tests/bpf-script-test-kbuild.c b/tools/perf/tests/bpf-script-test-kbuild.c
index 3626924..f1b48a4 100644
--- a/tools/perf/tests/bpf-script-test-kbuild.c
+++ b/tools/perf/tests/bpf-script-test-kbuild.c
@@ -6,7 +6,9 @@
 # error Need LINUX_VERSION_CODE
 # error Example: for 4.2 kernel, put 'clang-opt="-DLINUX_VERSION_CODE=0x40200" into llvm section of ~/.perfconfig'
 #endif
+#ifndef BUILTIN_CLANG_DEFAULT_INCLUDE
 #define SEC(NAME) __attribute__((section(NAME), used))
+#endif
 
 #include <uapi/linux/fs.h>
 #include <uapi/asm/ptrace.h>
diff --git a/tools/perf/tests/bpf-script-test-prologue.c b/tools/perf/tests/bpf-script-test-prologue.c
index ada812b..e2176c9 100644
--- a/tools/perf/tests/bpf-script-test-prologue.c
+++ b/tools/perf/tests/bpf-script-test-prologue.c
@@ -6,7 +6,6 @@
 # error Need LINUX_VERSION_CODE
 # error Example: for 4.2 kernel, put 'clang-opt="-DLINUX_VERSION_CODE=0x40200" into llvm section of ~/.perfconfig'
 #endif
-#define SEC(NAME) __attribute__((section(NAME), used))
 
 #include <uapi/linux/fs.h>
 
@@ -14,6 +13,9 @@
 #define FMODE_WRITE		0x2
 
 #ifndef BUILTIN_CLANG_DEFAULT_INCLUDE
+
+#define SEC(NAME) __attribute__((section(NAME), used))
+
 static void (*bpf_trace_printk)(const char *fmt, int fmt_size, ...) =
 	(void *) 6;
 #endif
diff --git a/tools/perf/tests/bpf-script-test-relocation.c b/tools/perf/tests/bpf-script-test-relocation.c
index 57c96a3..bb54926 100644
--- a/tools/perf/tests/bpf-script-test-relocation.c
+++ b/tools/perf/tests/bpf-script-test-relocation.c
@@ -9,6 +9,7 @@
 #define BPF_ANY 0
 #define BPF_MAP_TYPE_ARRAY 2
 
+#ifndef BUILTIN_CLANG_DEFAULT_INCLUDE
 struct bpf_map_def {
 	unsigned int type;
 	unsigned int key_size;
@@ -17,8 +18,6 @@ struct bpf_map_def {
 };
 
 #define SEC(NAME) __attribute__((section(NAME), used))
-
-#ifndef BUILTIN_CLANG_DEFAULT_INCLUDE
 #define BPF_FUNC_map_lookup_elem 1
 #define BPF_FUNC_map_update_elem 2
 
diff --git a/tools/perf/util/c++/Build b/tools/perf/util/c++/Build
index bd71abf..faa0268 100644
--- a/tools/perf/util/c++/Build
+++ b/tools/perf/util/c++/Build
@@ -1,3 +1,4 @@
 libperf-$(CONFIG_CLANGLLVM) += clang.o
 libperf-$(CONFIG_CLANGLLVM) += clang-test.o
 libperf-$(CONFIG_CLANGLLVM) += bpf-funcs-str.o
+libperf-$(CONFIG_CLANGLLVM) += bpf-helper-str.o
diff --git a/tools/perf/util/c++/bpf-helper-str.c b/tools/perf/util/c++/bpf-helper-str.c
new file mode 100644
index 0000000..17f915c
--- /dev/null
+++ b/tools/perf/util/c++/bpf-helper-str.c
@@ -0,0 +1,15 @@
+#include "clang-bpf-includes.h"
+const char clang_builtin_bpf_helper_str[] =
+"#ifdef BUILTIN_CLANG_DEFAULT_INCLUDE\n"
+"#ifndef BPF_HELPER_DEFINED\n"
+"#define BPF_HELPER_DEFINED\n"
+"struct bpf_map_def {\n"
+"	unsigned int type;\n"
+"	unsigned int key_size;\n"
+"	unsigned int value_size;\n"
+"	unsigned int max_entries;\n"
+"};\n"
+"#define SEC(NAME) __attribute__((section(NAME), used))\n"
+"#endif\n"
+"#endif"
+;
diff --git a/tools/perf/util/c++/clang-bpf-includes.h b/tools/perf/util/c++/clang-bpf-includes.h
index 385a5bb..577b40c 100644
--- a/tools/perf/util/c++/clang-bpf-includes.h
+++ b/tools/perf/util/c++/clang-bpf-includes.h
@@ -5,6 +5,7 @@ extern "C" {
 #endif
 
 extern const char clang_builtin_bpf_funcs_str[];
+extern const char clang_builtin_bpf_helper_str[];
 
 #ifdef __cplusplus
 }
diff --git a/tools/perf/util/c++/clang.cpp b/tools/perf/util/c++/clang.cpp
index feb69ea..d49305a 100644
--- a/tools/perf/util/c++/clang.cpp
+++ b/tools/perf/util/c++/clang.cpp
@@ -48,6 +48,7 @@ static struct BPFHeader {
 	llvm::StringRef Content;
 } BPFHeaders[] = {
 	{"/virtual/bpf-funcs.h", clang_builtin_bpf_funcs_str},
+	{"/virtual/bpf-helper.h", clang_builtin_bpf_helper_str},
 };
 
 static std::unique_ptr<llvm::LLVMContext> LLVMCtx;
-- 
2.10.1

[PATCH v4 17/18] perf clang builtin: Define hook helpers by default

[Wang Nan]

Append declarations of helpers to default include file. All functions
appear in exported_funcs array should be declared here except
test__clang_callback, because it is used for perf test only.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
 tools/perf/util/c++/bpf-helper-str.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/tools/perf/util/c++/bpf-helper-str.c b/tools/perf/util/c++/bpf-helper-str.c
index 17f915c..f4d6d57 100644
--- a/tools/perf/util/c++/bpf-helper-str.c
+++ b/tools/perf/util/c++/bpf-helper-str.c
@@ -10,6 +10,13 @@ const char clang_builtin_bpf_helper_str[] =
 "	unsigned int max_entries;\n"
 "};\n"
 "#define SEC(NAME) __attribute__((section(NAME), used))\n"
+"extern int printf(const char *, ...);\n"
+"extern int puts(const char *);\n"
+"extern int perf_map_update_elem(void *, void *, void *, void *, unsigned long);\n"
+"extern int perf_map_lookup_elem(void *, void *, void *, void *);\n"
+"extern int perf_map_get_next_key(void *, void *, void *, void *);\n"
+"extern int perf_map_pin(void *, void *, const char *);\n"
+"extern int perf_map_get(const char *);\n"
 "#endif\n"
 "#endif"
 ;
-- 
2.10.1

[PATCH v4 18/18] perf clang jit: Export getpid() to perf hook

[Wang Nan]

After this patch perf hooks can retrive pid of perf itself by calling
getpid. It is important for excluding event from perf.

This commit is also an example to show how to export more helpers to
hooked script.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
 tools/perf/util/c++/bpf-helper-str.c | 1 +
 tools/perf/util/c++/clang.cpp        | 1 +
 2 files changed, 2 insertions(+)

diff --git a/tools/perf/util/c++/bpf-helper-str.c b/tools/perf/util/c++/bpf-helper-str.c
index f4d6d57..1ad6ec0 100644
--- a/tools/perf/util/c++/bpf-helper-str.c
+++ b/tools/perf/util/c++/bpf-helper-str.c
@@ -12,6 +12,7 @@ const char clang_builtin_bpf_helper_str[] =
 "#define SEC(NAME) __attribute__((section(NAME), used))\n"
 "extern int printf(const char *, ...);\n"
 "extern int puts(const char *);\n"
+"extern int getpid(void);\n"
 "extern int perf_map_update_elem(void *, void *, void *, void *, unsigned long);\n"
 "extern int perf_map_lookup_elem(void *, void *, void *, void *);\n"
 "extern int perf_map_get_next_key(void *, void *, void *, void *);\n"
diff --git a/tools/perf/util/c++/clang.cpp b/tools/perf/util/c++/clang.cpp
index d49305a..ca5264c 100644
--- a/tools/perf/util/c++/clang.cpp
+++ b/tools/perf/util/c++/clang.cpp
@@ -239,6 +239,7 @@ static std::map<const std::string, const void *> exported_funcs =
 	EXPORT(test__clang_callback),
 	EXPORT(printf),
 	EXPORT(puts),
+	EXPORT(getpid),
 	EXPORT(JIT_HELPER_FUNC_NAME(map_update_elem)),
 	EXPORT(JIT_HELPER_FUNC_NAME(map_lookup_elem)),
 	EXPORT(JIT_HELPER_FUNC_NAME(map_get_next_key)),
-- 
2.10.1

Re: [PATCH v4 01/18] perf build: Check LLVM version in feature check

[Wangnan (F)]

On 2016/12/6 15:13, Wang Nan wrote:
> Cancel builtin llvm and clang support when LLVM version is
> less than 3.9.0: following commits uses newer API.
>
> Since Clang/LLVM's API is not guaranteed to be stable,
> add a test-llvm-version.cpp feature checker, issue warning if
> LLVM found in compiling environment is not tested yet.
>
> Signed-off-by: Wang Nan <wangnan0@huawei.com>
> Cc: Alexei Starovoitov <ast@fb.com>
> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
> Cc: He Kuang <hekuang@huawei.com>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: Joe Stringer <joe@ovn.org>
> Cc: Zefan Li <lizefan@huawei.com>
> Cc: pi3orama@163.com
> ---
>   tools/build/feature/Makefile              |  8 ++++++--
>   tools/build/feature/test-llvm-version.cpp | 12 ++++++++++++
>   tools/build/feature/test-llvm.cpp         |  5 +++++
>   tools/perf/Makefile.config                |  8 ++++++--
>   4 files changed, 29 insertions(+), 4 deletions(-)
>   create mode 100644 tools/build/feature/test-llvm-version.cpp

[SNIP]

> diff --git a/tools/build/feature/test-llvm-version.cpp b/tools/build/feature/test-llvm-version.cpp
> new file mode 100644
> index 0000000..e86b642
> --- /dev/null
> +++ b/tools/build/feature/test-llvm-version.cpp
> @@ -0,0 +1,12 @@
> +#include <cstdio>
> +#include "llvm/Config/llvm-config.h"
> +
> +#define NUM_VERSION (((LLVM_VERSION_MAJOR) << 16) + (LLVM_VERSION_MINOR << 8) + LLVM_VERSION_PATCH)
> +#define pass int main() {printf("%x\n", NUM_VERSION); return 0;}
> +
> +#if NUM_VERSION >= 0x030900
> +pass
> +#else
> +# error This LLVM is not tested yet.
> +#endif
> +
Sorry for this blank line. Will resend.

[PATCH v4 01/18 -cleanup] perf build: Check LLVM version in feature check

[Wang Nan]

Cancel builtin llvm and clang support when LLVM version is
less than 3.9.0: following commits uses newer API.

Since Clang/LLVM's API is not guaranteed to be stable,
add a test-llvm-version.cpp feature checker, issue warning if
LLVM found in compiling environment is not tested yet.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Joe Stringer <joe@ovn.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
 tools/build/feature/Makefile              |  8 ++++++--
 tools/build/feature/test-llvm-version.cpp | 11 +++++++++++
 tools/build/feature/test-llvm.cpp         |  5 +++++
 tools/perf/Makefile.config                |  8 ++++++--
 4 files changed, 28 insertions(+), 4 deletions(-)
 create mode 100644 tools/build/feature/test-llvm-version.cpp

diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
index 303196c..b564a2e 100644
--- a/tools/build/feature/Makefile
+++ b/tools/build/feature/Makefile
@@ -231,14 +231,18 @@ $(OUTPUT)test-jvmti.bin:
 	$(BUILD)
 
 $(OUTPUT)test-llvm.bin:
-	$(BUILDXX) -std=gnu++11 					\
+	$(BUILDXX) -std=gnu++11 				\
 		-I$(shell $(LLVM_CONFIG) --includedir) 		\
 		-L$(shell $(LLVM_CONFIG) --libdir)		\
 		$(shell $(LLVM_CONFIG) --libs Core BPF)		\
 		$(shell $(LLVM_CONFIG) --system-libs)
 
+$(OUTPUT)test-llvm-version.bin:
+	$(BUILDXX) -std=gnu++11 				\
+		-I$(shell $(LLVM_CONFIG) --includedir)
+
 $(OUTPUT)test-clang.bin:
-	$(BUILDXX) -std=gnu++11 					\
+	$(BUILDXX) -std=gnu++11 				\
 		-I$(shell $(LLVM_CONFIG) --includedir) 		\
 		-L$(shell $(LLVM_CONFIG) --libdir)		\
 		-Wl,--start-group -lclangBasic -lclangDriver	\
diff --git a/tools/build/feature/test-llvm-version.cpp b/tools/build/feature/test-llvm-version.cpp
new file mode 100644
index 0000000..896d317
--- /dev/null
+++ b/tools/build/feature/test-llvm-version.cpp
@@ -0,0 +1,11 @@
+#include <cstdio>
+#include "llvm/Config/llvm-config.h"
+
+#define NUM_VERSION (((LLVM_VERSION_MAJOR) << 16) + (LLVM_VERSION_MINOR << 8) + LLVM_VERSION_PATCH)
+#define pass int main() {printf("%x\n", NUM_VERSION); return 0;}
+
+#if NUM_VERSION >= 0x030900
+pass
+#else
+# error This LLVM is not tested yet.
+#endif
diff --git a/tools/build/feature/test-llvm.cpp b/tools/build/feature/test-llvm.cpp
index d8d2cee..455a332 100644
--- a/tools/build/feature/test-llvm.cpp
+++ b/tools/build/feature/test-llvm.cpp
@@ -1,5 +1,10 @@
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/raw_ostream.h"
+#define NUM_VERSION (((LLVM_VERSION_MAJOR) << 16) + (LLVM_VERSION_MINOR << 8) + LLVM_VERSION_PATCH)
+
+#if NUM_VERSION < 0x030900
+# error "LLVM version too low"
+#endif
 int main()
 {
 	llvm::errs() << "Hello World!\n";
diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index 09c2a98..2f4d5b0 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -802,12 +802,13 @@ ifdef LIBCLANGLLVM
     msg := $(warning No g++ found, disable clang and llvm support. Please install g++)
   else
     $(call feature_check,llvm)
+    $(call feature_check,llvm-version)
     ifneq ($(feature-llvm), 1)
-      msg := $(warning No libLLVM found, disable clang and llvm support. Please install llvm-dev)
+      msg := $(warning No libLLVM found, disable clang and llvm support. Please install llvm-dev (>= 3.9.0))
     else
       $(call feature_check,clang)
       ifneq ($(feature-clang), 1)
-        msg := $(warning No libclang found, disable clang and llvm support. Please install libclang-dev)
+        msg := $(warning No libclang found, disable clang and llvm support. Please install libclang-dev (>= 3.9.0))
       else
         CFLAGS += -DHAVE_LIBCLANGLLVM_SUPPORT
         CXXFLAGS += -DHAVE_LIBCLANGLLVM_SUPPORT -I$(shell $(LLVM_CONFIG) --includedir)
@@ -816,6 +817,9 @@ ifdef LIBCLANGLLVM
 	USE_CXX = 1
 	USE_LLVM = 1
 	USE_CLANG = 1
+        ifneq ($(feature-llvm-version),1)
+          msg := $(warning This version of llvm is not tested. May cause building error)
+        endif
       endif
     endif
   endif
-- 
2.10.1

Re: [PATCH v4 01/18 -cleanup] perf build: Check LLVM version in feature check

[Arnaldo Carvalho de Melo]

Em Tue, Dec 06, 2016 at 07:22:30AM +0000, Wang Nan escreveu:
> Cancel builtin llvm and clang support when LLVM version is
> less than 3.9.0: following commits uses newer API.
> 
> Since Clang/LLVM's API is not guaranteed to be stable,
> add a test-llvm-version.cpp feature checker, issue warning if
> LLVM found in compiling environment is not tested yet.

Ok, did a few clarifications in the warning message and tested it with a
f25 kit, i.e. clang/LLVM 3.8, all seems ok now, please see:

https://git.kernel.org/cgit/linux/kernel/git/acme/linux.git/commit/?h=perf/core&id=464cf82b6c9304e981f3af831ca8ab608e862687

For my case, I end up getting this message:

  Makefile.config:807: No suitable libLLVM found, disabling builtin clang and LLVM support. Please install llvm-dev(el) (>= 3.9.0)

Please holler if it is in any way misleading or erroneous.

- Arnaldo
 
> Signed-off-by: Wang Nan <wangnan0@huawei.com>
> Cc: Alexei Starovoitov <ast@fb.com>
> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
> Cc: He Kuang <hekuang@huawei.com>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: Joe Stringer <joe@ovn.org>
> Cc: Zefan Li <lizefan@huawei.com>
> Cc: pi3orama@163.com
> ---
>  tools/build/feature/Makefile              |  8 ++++++--
>  tools/build/feature/test-llvm-version.cpp | 11 +++++++++++
>  tools/build/feature/test-llvm.cpp         |  5 +++++
>  tools/perf/Makefile.config                |  8 ++++++--
>  4 files changed, 28 insertions(+), 4 deletions(-)
>  create mode 100644 tools/build/feature/test-llvm-version.cpp
> 
> diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
> index 303196c..b564a2e 100644
> --- a/tools/build/feature/Makefile
> +++ b/tools/build/feature/Makefile
> @@ -231,14 +231,18 @@ $(OUTPUT)test-jvmti.bin:
>  	$(BUILD)
>  
>  $(OUTPUT)test-llvm.bin:
> -	$(BUILDXX) -std=gnu++11 					\
> +	$(BUILDXX) -std=gnu++11 				\
>  		-I$(shell $(LLVM_CONFIG) --includedir) 		\
>  		-L$(shell $(LLVM_CONFIG) --libdir)		\
>  		$(shell $(LLVM_CONFIG) --libs Core BPF)		\
>  		$(shell $(LLVM_CONFIG) --system-libs)
>  
> +$(OUTPUT)test-llvm-version.bin:
> +	$(BUILDXX) -std=gnu++11 				\
> +		-I$(shell $(LLVM_CONFIG) --includedir)
> +
>  $(OUTPUT)test-clang.bin:
> -	$(BUILDXX) -std=gnu++11 					\
> +	$(BUILDXX) -std=gnu++11 				\
>  		-I$(shell $(LLVM_CONFIG) --includedir) 		\
>  		-L$(shell $(LLVM_CONFIG) --libdir)		\
>  		-Wl,--start-group -lclangBasic -lclangDriver	\
> diff --git a/tools/build/feature/test-llvm-version.cpp b/tools/build/feature/test-llvm-version.cpp
> new file mode 100644
> index 0000000..896d317
> --- /dev/null
> +++ b/tools/build/feature/test-llvm-version.cpp
> @@ -0,0 +1,11 @@
> +#include <cstdio>
> +#include "llvm/Config/llvm-config.h"
> +
> +#define NUM_VERSION (((LLVM_VERSION_MAJOR) << 16) + (LLVM_VERSION_MINOR << 8) + LLVM_VERSION_PATCH)
> +#define pass int main() {printf("%x\n", NUM_VERSION); return 0;}
> +
> +#if NUM_VERSION >= 0x030900
> +pass
> +#else
> +# error This LLVM is not tested yet.
> +#endif
> diff --git a/tools/build/feature/test-llvm.cpp b/tools/build/feature/test-llvm.cpp
> index d8d2cee..455a332 100644
> --- a/tools/build/feature/test-llvm.cpp
> +++ b/tools/build/feature/test-llvm.cpp
> @@ -1,5 +1,10 @@
>  #include "llvm/Support/ManagedStatic.h"
>  #include "llvm/Support/raw_ostream.h"
> +#define NUM_VERSION (((LLVM_VERSION_MAJOR) << 16) + (LLVM_VERSION_MINOR << 8) + LLVM_VERSION_PATCH)
> +
> +#if NUM_VERSION < 0x030900
> +# error "LLVM version too low"
> +#endif
>  int main()
>  {
>  	llvm::errs() << "Hello World!\n";
> diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
> index 09c2a98..2f4d5b0 100644
> --- a/tools/perf/Makefile.config
> +++ b/tools/perf/Makefile.config
> @@ -802,12 +802,13 @@ ifdef LIBCLANGLLVM
>      msg := $(warning No g++ found, disable clang and llvm support. Please install g++)
>    else
>      $(call feature_check,llvm)
> +    $(call feature_check,llvm-version)
>      ifneq ($(feature-llvm), 1)
> -      msg := $(warning No libLLVM found, disable clang and llvm support. Please install llvm-dev)
> +      msg := $(warning No libLLVM found, disable clang and llvm support. Please install llvm-dev (>= 3.9.0))
>      else
>        $(call feature_check,clang)
>        ifneq ($(feature-clang), 1)
> -        msg := $(warning No libclang found, disable clang and llvm support. Please install libclang-dev)
> +        msg := $(warning No libclang found, disable clang and llvm support. Please install libclang-dev (>= 3.9.0))
>        else
>          CFLAGS += -DHAVE_LIBCLANGLLVM_SUPPORT
>          CXXFLAGS += -DHAVE_LIBCLANGLLVM_SUPPORT -I$(shell $(LLVM_CONFIG) --includedir)
> @@ -816,6 +817,9 @@ ifdef LIBCLANGLLVM
>  	USE_CXX = 1
>  	USE_LLVM = 1
>  	USE_CLANG = 1
> +        ifneq ($(feature-llvm-version),1)
> +          msg := $(warning This version of llvm is not tested. May cause building error)
> +        endif
>        endif
>      endif
>    endif
> -- 
> 2.10.1

[tip:perf/core] perf build: Check LLVM version in feature check

[tip-bot for Wang Nan]

Commit-ID:  a940cad331e79cc03d9ae74f56a2c7cb810bdce9
Gitweb:     http://git.kernel.org/tip/a940cad331e79cc03d9ae74f56a2c7cb810bdce9
Author:     Wang Nan <wangnan0@huawei.com>
AuthorDate: Tue, 6 Dec 2016 07:22:30 +0000
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Tue, 6 Dec 2016 13:21:55 -0300

perf build: Check LLVM version in feature check

Cancel builtin llvm and clang support when LLVM version is less than
3.9.0: following commits uses newer API.

Since Clang/LLVM's API is not guaranteed to be stable, add a
test-llvm-version.cpp feature checker, issue warning if LLVM found in
compiling environment is not tested yet.

Committer Notes:

Testing it:

Environment:

  $ cat /etc/fedora-release
  Fedora release 25 (Twenty Five)
  $ rpm -q llvm-devel clang-devel
  llvm-devel-3.8.0-1.fc25.x86_64
  clang-devel-3.8.0-2.fc25.x86_64
  $

Before:

  $  make -k LIBCLANGLLVM=1 O=/tmp/build/perf -C tools/perf install-bin
  make: Entering directory '/home/acme/git/linux/tools/perf'
    BUILD:   Doing 'make -j4' parallel build
  Warning: tools/include/uapi/linux/bpf.h differs from kernel
  Warning: tools/arch/arm/include/uapi/asm/kvm.h differs from kernel
    INSTALL  GTK UI
    LINK     /tmp/build/perf/perf
  /tmp/build/perf/libperf.a(libperf-in.o): In function `perf::createCompilerInvocation(llvm::SmallVector<char const*, 16u>, llvm::StringRef&, clang::DiagnosticsEngine&)':
  /home/acme/git/linux/tools/perf/util/c++/clang.cpp:56: undefined reference to `clang::tooling::newInvocation(clang::DiagnosticsEngine*, llvm::SmallVector<char const*, 16u> const&)'
  /tmp/build/perf/libperf.a(libperf-in.o): In function `perf::getModuleFromSource(llvm::SmallVector<char const*, 16u>, llvm::StringRef, llvm::IntrusiveRefCntPtr<clang::vfs::FileSystem>)':
  /home/acme/git/linux/tools/perf/util/c++/clang.cpp:68: undefined reference to `clang::CompilerInstance::CompilerInstance(std::shared_ptr<clang::PCHContainerOperations>, bool)'
  /home/acme/git/linux/tools/perf/util/c++/clang.cpp:69: undefined reference to `clang::CompilerInstance::createDiagnostics(clang::DiagnosticConsumer*, bool)'
  <SNIP>

After:

  Makefile.config:807: No suitable libLLVM found, disabling builtin clang and llvm support. Please install llvm-dev(el) (>= 3.9.0)

Updating the environment to a locally built LLVM 4.0 + clang 3.9 (forgot
to git pull, duh) combo, all works as expected, it is properly detected
and built into the resulting perf binary.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Reported-and-Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Joe Stringer <joe@ovn.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/20161206072230.7651-1-wangnan0@huawei.com
[ Change the warning message a bit (add 'suitable' and 'builtin'), clarifying it, see committer notes above ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/build/feature/Makefile              |  8 ++++++--
 tools/build/feature/test-llvm-version.cpp | 11 +++++++++++
 tools/build/feature/test-llvm.cpp         |  5 +++++
 tools/perf/Makefile.config                |  8 ++++++--
 4 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
index 303196c..b564a2e 100644
--- a/tools/build/feature/Makefile
+++ b/tools/build/feature/Makefile
@@ -231,14 +231,18 @@ $(OUTPUT)test-jvmti.bin:
 	$(BUILD)
 
 $(OUTPUT)test-llvm.bin:
-	$(BUILDXX) -std=gnu++11 					\
+	$(BUILDXX) -std=gnu++11 				\
 		-I$(shell $(LLVM_CONFIG) --includedir) 		\
 		-L$(shell $(LLVM_CONFIG) --libdir)		\
 		$(shell $(LLVM_CONFIG) --libs Core BPF)		\
 		$(shell $(LLVM_CONFIG) --system-libs)
 
+$(OUTPUT)test-llvm-version.bin:
+	$(BUILDXX) -std=gnu++11 				\
+		-I$(shell $(LLVM_CONFIG) --includedir)
+
 $(OUTPUT)test-clang.bin:
-	$(BUILDXX) -std=gnu++11 					\
+	$(BUILDXX) -std=gnu++11 				\
 		-I$(shell $(LLVM_CONFIG) --includedir) 		\
 		-L$(shell $(LLVM_CONFIG) --libdir)		\
 		-Wl,--start-group -lclangBasic -lclangDriver	\
diff --git a/tools/build/feature/test-llvm-version.cpp b/tools/build/feature/test-llvm-version.cpp
new file mode 100644
index 0000000..896d317
--- /dev/null
+++ b/tools/build/feature/test-llvm-version.cpp
@@ -0,0 +1,11 @@
+#include <cstdio>
+#include "llvm/Config/llvm-config.h"
+
+#define NUM_VERSION (((LLVM_VERSION_MAJOR) << 16) + (LLVM_VERSION_MINOR << 8) + LLVM_VERSION_PATCH)
+#define pass int main() {printf("%x\n", NUM_VERSION); return 0;}
+
+#if NUM_VERSION >= 0x030900
+pass
+#else
+# error This LLVM is not tested yet.
+#endif
diff --git a/tools/build/feature/test-llvm.cpp b/tools/build/feature/test-llvm.cpp
index d8d2cee..455a332 100644
--- a/tools/build/feature/test-llvm.cpp
+++ b/tools/build/feature/test-llvm.cpp
@@ -1,5 +1,10 @@
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/raw_ostream.h"
+#define NUM_VERSION (((LLVM_VERSION_MAJOR) << 16) + (LLVM_VERSION_MINOR << 8) + LLVM_VERSION_PATCH)
+
+#if NUM_VERSION < 0x030900
+# error "LLVM version too low"
+#endif
 int main()
 {
 	llvm::errs() << "Hello World!\n";
diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index 09c2a98..76c84f0 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -802,12 +802,13 @@ ifdef LIBCLANGLLVM
     msg := $(warning No g++ found, disable clang and llvm support. Please install g++)
   else
     $(call feature_check,llvm)
+    $(call feature_check,llvm-version)
     ifneq ($(feature-llvm), 1)
-      msg := $(warning No libLLVM found, disable clang and llvm support. Please install llvm-dev)
+      msg := $(warning No suitable libLLVM found, disabling builtin clang and LLVM support. Please install llvm-dev(el) (>= 3.9.0))
     else
       $(call feature_check,clang)
       ifneq ($(feature-clang), 1)
-        msg := $(warning No libclang found, disable clang and llvm support. Please install libclang-dev)
+        msg := $(warning No suitable libclang found, disabling builtin clang and LLVM support. Please install libclang-dev(el) (>= 3.9.0))
       else
         CFLAGS += -DHAVE_LIBCLANGLLVM_SUPPORT
         CXXFLAGS += -DHAVE_LIBCLANGLLVM_SUPPORT -I$(shell $(LLVM_CONFIG) --includedir)
@@ -816,6 +817,9 @@ ifdef LIBCLANGLLVM
 	USE_CXX = 1
 	USE_LLVM = 1
 	USE_CLANG = 1
+        ifneq ($(feature-llvm-version),1)
+          msg := $(warning This version of LLVM is not tested. May cause build errors)
+        endif
       endif
     endif
   endif