perf clang: Allow passing CFLAGS to builtin clang

Improve getModuleFromSource() API to accept a cflags list. This feature
will be used to pass LINUX_VERSION_CODE and -I flags.

Signed-off-by: Wang Nan <wangnan0@huawei.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/20161126070354.141764-13-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/c++/clang-test.cpp

@@ -16,8 +16,9 @@ int test__clang_to_IR(void)
 	perf_clang_scope _scope;
 
 	std::unique_ptr<llvm::Module> M =
-		perf::getModuleFromSource("perf-test.c",
-					  "int myfunc(void) {return 1;}");
+		perf::getModuleFromSource({"-DRESULT=1"},
+					  "perf-test.c",
+					  "int myfunc(void) {return RESULT;}");
 
 	if (!M)
 		return -1;

tools/perf/util/c++/clang.cpp

@@ -29,7 +29,8 @@ static std::unique_ptr<llvm::LLVMContext> LLVMCtx;
 using namespace clang;
 
 static CompilerInvocation *
-createCompilerInvocation(StringRef& Path, DiagnosticsEngine& Diags)
+createCompilerInvocation(llvm::opt::ArgStringList CFlags, StringRef& Path,
+			 DiagnosticsEngine& Diags)
 {
 	llvm::opt::ArgStringList CCArgs {
 		"-cc1",
@@ -45,6 +46,8 @@ createCompilerInvocation(StringRef& Path, DiagnosticsEngine& Diags)
 		"-Wno-unused-value",
 		"-Wno-pointer-sign",
 		"-x", "c"};
+
+	CCArgs.append(CFlags.begin(), CFlags.end());
 	CompilerInvocation *CI = tooling::newInvocation(&Diags, CCArgs);
 
 	FrontendOptions& Opts = CI->getFrontendOpts();
@@ -54,8 +57,8 @@ createCompilerInvocation(StringRef& Path, DiagnosticsEngine& Diags)
 }
 
 static std::unique_ptr<llvm::Module>
-getModuleFromSource(StringRef Path,
-		    IntrusiveRefCntPtr<vfs::FileSystem> VFS)
+getModuleFromSource(llvm::opt::ArgStringList CFlags,
+		    StringRef Path, IntrusiveRefCntPtr<vfs::FileSystem> VFS)
 {
 	CompilerInstance Clang;
 	Clang.createDiagnostics();
@@ -63,7 +66,8 @@ getModuleFromSource(StringRef Path,
 	Clang.setVirtualFileSystem(&*VFS);
 
 	IntrusiveRefCntPtr<CompilerInvocation> CI =
-		createCompilerInvocation(Path, Clang.getDiagnostics());
+		createCompilerInvocation(std::move(CFlags), Path,
+					 Clang.getDiagnostics());
 	Clang.setInvocation(&*CI);
 
 	std::unique_ptr<CodeGenAction> Act(new EmitLLVMOnlyAction(&*LLVMCtx));
@@ -74,7 +78,8 @@ getModuleFromSource(StringRef Path,
 }
 
 std::unique_ptr<llvm::Module>
-getModuleFromSource(StringRef Name, StringRef Content)
+getModuleFromSource(llvm::opt::ArgStringList CFlags,
+		    StringRef Name, StringRef Content)
 {
 	using namespace vfs;
 
@@ -90,14 +95,14 @@ getModuleFromSource(StringRef Name, StringRef Content)
 	OverlayFS->pushOverlay(MemFS);
 	MemFS->addFile(Twine(Name), 0, llvm::MemoryBuffer::getMemBuffer(Content));
 
-	return getModuleFromSource(Name, OverlayFS);
+	return getModuleFromSource(std::move(CFlags), Name, OverlayFS);
 }
 
 std::unique_ptr<llvm::Module>
-getModuleFromSource(StringRef Path)
+getModuleFromSource(llvm::opt::ArgStringList CFlags, StringRef Path)
 {
 	IntrusiveRefCntPtr<vfs::FileSystem> VFS(vfs::getRealFileSystem());
-	return getModuleFromSource(Path, VFS);
+	return getModuleFromSource(std::move(CFlags), Path, VFS);
 }
 
 }

tools/perf/util/c++/clang.h

@@ -4,16 +4,20 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
+#include "llvm/Option/Option.h"
 #include <memory>
+
 namespace perf {
 
 using namespace llvm;
 
 std::unique_ptr<Module>
-getModuleFromSource(StringRef Name, StringRef Content);
+getModuleFromSource(opt::ArgStringList CFlags,
+		    StringRef Name, StringRef Content);
 
 std::unique_ptr<Module>
-getModuleFromSource(StringRef Path);
+getModuleFromSource(opt::ArgStringList CFlags,
+		    StringRef Path);
 
 }
 #endif