[PATCH v3 16/30] perf clang: Pass full path to builtin clang

From: Wang Nan
Date: Sat Nov 26 2016 - 02:07:26 EST


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@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/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 1e97415..610f1cf 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"
@@ -164,7 +165,7 @@ 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)
{
@@ -173,8 +174,11 @@ 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