[PATCH v3 14/30] perf clang: Support compile IR to BPF object and add testcase
From: Wang Nan
Date: Sat Nov 26 2016 - 02:07:37 EST
getBPFObjectFromModule() is introduced to compile LLVM IR(Module)
to BPF object. Add new testcase for it.
Test result:
$ ./buildperf/perf test -v clang
51: Test builtin clang support :
51.1: Test builtin clang compile C source to IR :
--- start ---
test child forked, pid 21822
test child finished with 0
---- end ----
Test builtin clang support subtest 0: Ok
51.2: Test builtin clang compile C source to ELF object :
--- start ---
test child forked, pid 21823
test child finished with 0
---- end ----
Test builtin clang support subtest 1: Ok
Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxx>
Cc: He Kuang <hekuang@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Zefan Li <lizefan@xxxxxxxxxx>
Cc: pi3orama@xxxxxxx
---
tools/perf/tests/clang.c | 6 ++++-
tools/perf/util/c++/clang-c.h | 1 +
tools/perf/util/c++/clang-test.cpp | 31 +++++++++++++++++++++-----
tools/perf/util/c++/clang.cpp | 45 ++++++++++++++++++++++++++++++++++++++
tools/perf/util/c++/clang.h | 3 +++
5 files changed, 79 insertions(+), 7 deletions(-)
diff --git a/tools/perf/tests/clang.c b/tools/perf/tests/clang.c
index 57ee160..2964c06 100644
--- a/tools/perf/tests/clang.c
+++ b/tools/perf/tests/clang.c
@@ -12,6 +12,10 @@ static struct {
.func = test__clang_to_IR,
.desc = "Test builtin clang compile C source to IR",
},
+ {
+ .func = test__clang_to_obj,
+ .desc = "Test builtin clang compile C source to ELF object",
+ },
#endif
};
@@ -33,7 +37,7 @@ int test__clang(int i __maybe_unused)
return TEST_SKIP;
}
#else
-int test__clang(int i __maybe_unused)
+int test__clang(int i)
{
if (i < 0 || i >= (int)ARRAY_SIZE(clang_testcase_table))
return TEST_FAIL;
diff --git a/tools/perf/util/c++/clang-c.h b/tools/perf/util/c++/clang-c.h
index dcde4b5..22b3936 100644
--- a/tools/perf/util/c++/clang-c.h
+++ b/tools/perf/util/c++/clang-c.h
@@ -9,6 +9,7 @@ extern void perf_clang__init(void);
extern void perf_clang__cleanup(void);
extern int test__clang_to_IR(void);
+extern int test__clang_to_obj(void);
#ifdef __cplusplus
}
diff --git a/tools/perf/util/c++/clang-test.cpp b/tools/perf/util/c++/clang-test.cpp
index d84e760..9b11e8c 100644
--- a/tools/perf/util/c++/clang-test.cpp
+++ b/tools/perf/util/c++/clang-test.cpp
@@ -13,15 +13,13 @@ public:
~perf_clang_scope() {perf_clang__cleanup();}
};
-extern "C" {
-
-int test__clang_to_IR(void)
+static std::unique_ptr<llvm::Module>
+__test__clang_to_IR(void)
{
- perf_clang_scope _scope;
unsigned int kernel_version;
if (fetch_kernel_version(&kernel_version, NULL, 0))
- return -1;
+ return std::unique_ptr<llvm::Module>(nullptr);
std::string cflag_kver("-DLINUX_VERSION_CODE=" +
std::to_string(kernel_version));
@@ -30,14 +28,35 @@ int test__clang_to_IR(void)
perf::getModuleFromSource({cflag_kver.c_str()},
"perf-test.c",
test_llvm__bpf_base_prog);
+ return M;
+}
+
+extern "C" {
+int test__clang_to_IR(void)
+{
+ perf_clang_scope _scope;
+ auto M = __test__clang_to_IR();
if (!M)
return -1;
-
for (llvm::Function& F : *M)
if (F.getName() == "bpf_func__SyS_epoll_wait")
return 0;
return -1;
}
+int test__clang_to_obj(void)
+{
+ perf_clang_scope _scope;
+
+ auto M = __test__clang_to_IR();
+ if (!M)
+ return -1;
+
+ auto Buffer = perf::getBPFObjectFromModule(&*M);
+ if (!Buffer)
+ return -1;
+ return 0;
+}
+
}
diff --git a/tools/perf/util/c++/clang.cpp b/tools/perf/util/c++/clang.cpp
index 715ca0a..2a1a75d 100644
--- a/tools/perf/util/c++/clang.cpp
+++ b/tools/perf/util/c++/clang.cpp
@@ -13,10 +13,15 @@
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Frontend/TextDiagnosticPrinter.h"
#include "clang/Tooling/Tooling.h"
+#include "llvm/IR/LegacyPassManager.h"
#include "llvm/IR/Module.h"
#include "llvm/Option/Option.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetOptions.h"
#include <memory>
#include "clang.h"
@@ -105,12 +110,52 @@ getModuleFromSource(llvm::opt::ArgStringList CFlags, StringRef Path)
return getModuleFromSource(std::move(CFlags), Path, VFS);
}
+std::unique_ptr<llvm::SmallVectorImpl<char>>
+getBPFObjectFromModule(llvm::Module *Module)
+{
+ using namespace llvm;
+
+ std::string TargetTriple("bpf-pc-linux");
+ std::string Error;
+ const Target* Target = TargetRegistry::lookupTarget(TargetTriple, Error);
+ if (!Target) {
+ llvm::errs() << Error;
+ return std::unique_ptr<llvm::SmallVectorImpl<char>>(nullptr);
+ }
+
+ llvm::TargetOptions Opt;
+ TargetMachine *TargetMachine =
+ Target->createTargetMachine(TargetTriple,
+ "generic", "",
+ Opt, Reloc::Static);
+
+ Module->setDataLayout(TargetMachine->createDataLayout());
+ Module->setTargetTriple(TargetTriple);
+
+ std::unique_ptr<SmallVectorImpl<char>> Buffer(new SmallVector<char, 0>());
+ raw_svector_ostream ostream(*Buffer);
+
+ legacy::PassManager PM;
+ if (TargetMachine->addPassesToEmitFile(PM, ostream,
+ TargetMachine::CGFT_ObjectFile)) {
+ llvm::errs() << "TargetMachine can't emit a file of this type\n";
+ return std::unique_ptr<llvm::SmallVectorImpl<char>>(nullptr);;
+ }
+ PM.run(*Module);
+
+ return std::move(Buffer);
+}
+
}
extern "C" {
void perf_clang__init(void)
{
perf::LLVMCtx.reset(new llvm::LLVMContext());
+ LLVMInitializeBPFTargetInfo();
+ LLVMInitializeBPFTarget();
+ LLVMInitializeBPFTargetMC();
+ LLVMInitializeBPFAsmPrinter();
}
void perf_clang__cleanup(void)
diff --git a/tools/perf/util/c++/clang.h b/tools/perf/util/c++/clang.h
index b4fc2a9..dd8b042 100644
--- a/tools/perf/util/c++/clang.h
+++ b/tools/perf/util/c++/clang.h
@@ -19,5 +19,8 @@ std::unique_ptr<Module>
getModuleFromSource(opt::ArgStringList CFlags,
StringRef Path);
+std::unique_ptr<llvm::SmallVectorImpl<char>>
+getBPFObjectFromModule(llvm::Module *Module);
+
}
#endif
--
2.10.1