[PATCH v2 07/18] perf clang: Use real file system for #include

From: Wang Nan
Date: Mon Sep 26 2016 - 03:30:59 EST


Utilize clang's OverlayFileSystem facility to enable VFS passed to
CompilerInstance can access files in real file system, so '#include'
directive can be used. Add a new getModuleFromSource for real file.

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>
---
tools/perf/util/c++/clang.cpp | 44 +++++++++++++++++++++++++++++++------------
tools/perf/util/c++/clang.h | 3 +++
2 files changed, 35 insertions(+), 12 deletions(-)

diff --git a/tools/perf/util/c++/clang.cpp b/tools/perf/util/c++/clang.cpp
index c17b117..cf96199 100644
--- a/tools/perf/util/c++/clang.cpp
+++ b/tools/perf/util/c++/clang.cpp
@@ -15,6 +15,7 @@
#include "clang/Tooling/Tooling.h"
#include "llvm/IR/Module.h"
#include "llvm/Option/Option.h"
+#include "llvm/Support/FileSystem.h"
#include "llvm/Support/ManagedStatic.h"
#include <memory>

@@ -27,14 +28,6 @@ static std::unique_ptr<llvm::LLVMContext> LLVMCtx;

using namespace clang;

-static vfs::InMemoryFileSystem *
-buildVFS(StringRef& Name, StringRef& Content)
-{
- vfs::InMemoryFileSystem *VFS = new vfs::InMemoryFileSystem(true);
- VFS->addFile(Twine(Name), 0, llvm::MemoryBuffer::getMemBuffer(Content));
- return VFS;
-}
-
static CompilerInvocation *
createCompilerInvocation(StringRef& Path, DiagnosticsEngine& Diags)
{
@@ -60,17 +53,17 @@ createCompilerInvocation(StringRef& Path, DiagnosticsEngine& Diags)
return CI;
}

-std::unique_ptr<llvm::Module>
-getModuleFromSource(StringRef Name, StringRef Content)
+static std::unique_ptr<llvm::Module>
+getModuleFromSource(StringRef Path,
+ IntrusiveRefCntPtr<vfs::FileSystem> VFS)
{
CompilerInstance Clang;
Clang.createDiagnostics();

- IntrusiveRefCntPtr<vfs::FileSystem> VFS = buildVFS(Name, Content);
Clang.setVirtualFileSystem(&*VFS);

IntrusiveRefCntPtr<CompilerInvocation> CI =
- createCompilerInvocation(Name, Clang.getDiagnostics());
+ createCompilerInvocation(Path, Clang.getDiagnostics());
Clang.setInvocation(&*CI);

std::unique_ptr<CodeGenAction> Act(new EmitLLVMOnlyAction(&*LLVMCtx));
@@ -80,6 +73,33 @@ getModuleFromSource(StringRef Name, StringRef Content)
return Act->takeModule();
}

+std::unique_ptr<llvm::Module>
+getModuleFromSource(StringRef Name, StringRef Content)
+{
+ using namespace vfs;
+
+ llvm::IntrusiveRefCntPtr<OverlayFileSystem> OverlayFS(
+ new OverlayFileSystem(getRealFileSystem()));
+ llvm::IntrusiveRefCntPtr<InMemoryFileSystem> MemFS(
+ new InMemoryFileSystem(true));
+
+ /*
+ * pushOverlay helps setting working dir for MemFS. Must call
+ * before addFile.
+ */
+ OverlayFS->pushOverlay(MemFS);
+ MemFS->addFile(Twine(Name), 0, llvm::MemoryBuffer::getMemBuffer(Content));
+
+ return getModuleFromSource(Name, OverlayFS);
+}
+
+std::unique_ptr<llvm::Module>
+getModuleFromSource(StringRef Path)
+{
+ IntrusiveRefCntPtr<vfs::FileSystem> VFS(vfs::getRealFileSystem());
+ return getModuleFromSource(Path, VFS);
+}
+
}

extern "C" {
diff --git a/tools/perf/util/c++/clang.h b/tools/perf/util/c++/clang.h
index f64483b..90aff01 100644
--- a/tools/perf/util/c++/clang.h
+++ b/tools/perf/util/c++/clang.h
@@ -12,5 +12,8 @@ using namespace llvm;
std::unique_ptr<Module>
getModuleFromSource(StringRef Name, StringRef Content);

+std::unique_ptr<Module>
+getModuleFromSource(StringRef Path);
+
}
#endif
--
1.8.3.4