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 <wangn...@huawei.com>
Cc: Arnaldo Carvalho de Melo <a...@redhat.com>
Cc: Alexei Starovoitov <a...@fb.com>
Cc: He Kuang <heku...@huawei.com>
Cc: Jiri Olsa <jo...@kernel.org>
Cc: Zefan Li <lize...@huawei.com>
Cc: pi3or...@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 610f1cf..3a3b9791 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 {
@@ -147,6 +149,101 @@ 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" {
@@ -174,11 +271,11 @@ 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
