* Lambdas: N2927_
* But *not* ``std::function``, until Clang implements `MSVC-compatible RTTI`_.
+ In many cases, you may be able to use ``llvm::function_ref`` instead, and it
+ is a superior choice in those cases.
* And *not* lambdas with default arguments.
* ``decltype``: N2343_
when defining a function which should be able to efficiently accept concatenated
strings.
+.. _function_apis:
+
+Passing functions and other callable objects
+--------------------------------------------
+
+Sometimes you may want a function to be passed a callback object. In order to
+support lambda expressions and other function objects, you should not use the
+traditional C approach of taking a function pointer and an opaque cookie:
+
+.. code-block:: c++
+
+ void takeCallback(bool (*Callback)(Function *, void *), void *Cookie);
+
+Instead, use one of the following approaches:
+
+Function template
+^^^^^^^^^^^^^^^^^
+
+If you don't mind putting the definition of your function into a header file,
+make it a function template that is templated on the callable type.
+
+.. code-block:: c++
+
+ template<typename Callable>
+ void takeCallback(Callable Callback) {
+ Callback(1, 2, 3);
+ }
+
+The ``function_ref`` class template
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The ``function_ref``
+(`doxygen <http://llvm.org/doxygen/classllvm_1_1function_ref.html>`__) class
+template represents a reference to a callable object, templated over the type
+of the callable. This is a good choice for passing a callback to a function,
+if you don't need to hold onto the callback after the function returns.
+
+``function_ref<Ret(Param1, Param2, ...)>`` can be implicitly constructed from
+any callable object that can be called with arguments of type ``Param1``,
+``Param2``, ..., and returns a value that can be converted to type ``Ret``.
+For example:
+
+.. code-block:: c++
+
+ void visitBasicBlocks(Function *F, function_ref<bool (BasicBlock*)> Callback) {
+ for (BasicBlock &BB : *F)
+ if (Callback(&BB))
+ return;
+ }
+
+can be called using:
+
+.. code-block:: c++
+
+ visitBasicBlocks(F, [&](BasicBlock *BB) {
+ if (process(BB))
+ return isEmpty(BB);
+ return false;
+ });
+
+Note that a ``function_ref`` object contains pointers to external memory, so
+it is not generally safe to store an instance of the class (unless you know
+that the external storage will not be freed).
+``function_ref`` is small enough that it should always be passed by value.
+
+``std::function``
+^^^^^^^^^^^^^^^^^
+
+You cannot use ``std::function`` within LLVM code, because it is not supported
+by all our target toolchains.
+
+
.. _DEBUG:
The ``DEBUG()`` macro and ``-debug`` option
}
};
+/// An efficient, type-erasing, non-owning reference to a callable. This is
+/// intended for use as the type of a function parameter that is not used
+/// after the function in question returns.
+///
+/// This class does not own the callable, so it is not in general safe to store
+/// a function_ref.
+template<typename Fn> class function_ref;
+
+#if LLVM_HAS_VARIADIC_TEMPLATES
+
+template<typename Ret, typename ...Params>
+class function_ref<Ret(Params...)> {
+ Ret (*callback)(void *callable, Params ...params);
+ void *callable;
+
+ template<typename Callable>
+ static Ret callback_fn(void *callable, Params ...params) {
+ return (*reinterpret_cast<Callable*>(callable))(
+ std::forward<Params>(params)...);
+ }
+
+public:
+ template<typename Callable>
+ function_ref(Callable &&callable)
+ : callback(callback_fn<typename std::remove_reference<Callable>::type>),
+ callable(reinterpret_cast<void *>(&callable)) {}
+ Ret operator()(Params ...params) const {
+ return callback(callable, std::forward<Params>(params)...);
+ }
+};
+
+#else
+
+template<typename Ret>
+class function_ref<Ret()> {
+ Ret (*callback)(void *callable);
+ void *callable;
+
+ template<typename Callable>
+ static Ret callback_fn(void *callable) {
+ return (*reinterpret_cast<Callable*>(callable))();
+ }
+
+public:
+ template<typename Callable>
+ function_ref(Callable &&callable)
+ : callback(callback_fn<typename std::remove_reference<Callable>::type>),
+ callable(reinterpret_cast<void *>(&callable)) {}
+ Ret operator()() const { return callback(callable); }
+};
+
+template<typename Ret, typename Param1>
+class function_ref<Ret(Param1)> {
+ Ret (*callback)(void *callable, Param1 param1);
+ void *callable;
+
+ template<typename Callable>
+ static Ret callback_fn(void *callable, Param1 param1) {
+ return (*reinterpret_cast<Callable*>(callable))(
+ std::forward<Param1>(param1));
+ }
+
+public:
+ template<typename Callable>
+ function_ref(Callable &&callable)
+ : callback(callback_fn<typename std::remove_reference<Callable>::type>),
+ callable(reinterpret_cast<void *>(&callable)) {}
+ Ret operator()(Param1 param1) {
+ return callback(callable, std::forward<Param1>(param1));
+ }
+};
+
+template<typename Ret, typename Param1, typename Param2>
+class function_ref<Ret(Param1, Param2)> {
+ Ret (*callback)(void *callable, Param1 param1, Param2 param2);
+ void *callable;
+
+ template<typename Callable>
+ static Ret callback_fn(void *callable, Param1 param1, Param2 param2) {
+ return (*reinterpret_cast<Callable*>(callable))(
+ std::forward<Param1>(param1),
+ std::forward<Param2>(param2));
+ }
+
+public:
+ template<typename Callable>
+ function_ref(Callable &&callable)
+ : callback(callback_fn<typename std::remove_reference<Callable>::type>),
+ callable(reinterpret_cast<void *>(&callable)) {}
+ Ret operator()(Param1 param1, Param2 param2) {
+ return callback(callable,
+ std::forward<Param1>(param1),
+ std::forward<Param2>(param2));
+ }
+};
+
+template<typename Ret, typename Param1, typename Param2, typename Param3>
+class function_ref<Ret(Param1, Param2, Param3)> {
+ Ret (*callback)(void *callable, Param1 param1, Param2 param2, Param3 param3);
+ void *callable;
+
+ template<typename Callable>
+ static Ret callback_fn(void *callable, Param1 param1, Param2 param2,
+ Param3 param3) {
+ return (*reinterpret_cast<Callable*>(callable))(
+ std::forward<Param1>(param1),
+ std::forward<Param2>(param2),
+ std::forward<Param3>(param3));
+ }
+
+public:
+ template<typename Callable>
+ function_ref(Callable &&callable)
+ : callback(callback_fn<typename std::remove_reference<Callable>::type>),
+ callable(reinterpret_cast<void *>(&callable)) {}
+ Ret operator()(Param1 param1, Param2 param2, Param3 param3) {
+ return callback(callable,
+ std::forward<Param1>(param1),
+ std::forward<Param2>(param2),
+ std::forward<Param3>(param3));
+ }
+};
+
+#endif
+
// deleter - Very very very simple method that is used to invoke operator
// delete on something. It is used like this:
//
#include <string>
+#include "llvm/ADT/STLExtras.h"
+
namespace llvm {
class StringRef;
class CrashRecoveryContextCleanup;
-
+
/// \brief Crash recovery helper object.
///
/// This class implements support for running operations in a safe context so
void *Impl;
CrashRecoveryContextCleanup *head;
- /// An adaptor to convert an arbitrary functor into a void(void*), void* pair.
- template<typename T> struct FunctorAdaptor {
- T Fn;
- static void invoke(void *Data) {
- return static_cast<FunctorAdaptor<T>*>(Data)->Fn();
- }
- typedef void Callback(void*);
- Callback *fn() { return &invoke; }
- void *arg() { return this; }
- };
-
public:
CrashRecoveryContext() : Impl(nullptr), head(nullptr) {}
~CrashRecoveryContext();
-
+
void registerCleanup(CrashRecoveryContextCleanup *cleanup);
void unregisterCleanup(CrashRecoveryContextCleanup *cleanup);
/// make as little assumptions as possible about the program state when
/// RunSafely has returned false. Clients can use getBacktrace() to retrieve
/// the backtrace of the crash on failures.
- bool RunSafely(void (*Fn)(void*), void *UserData);
- template<typename Functor>
- bool RunSafely(Functor Fn) {
- FunctorAdaptor<Functor> Adaptor = { Fn };
- return RunSafely(Adaptor.fn(), Adaptor.arg());
+ bool RunSafely(function_ref<void()> Fn);
+ bool RunSafely(void (*Fn)(void*), void *UserData) {
+ return RunSafely([&]() { Fn(UserData); });
}
/// \brief Execute the provide callback function (with the given arguments) in
/// requested stack size).
///
/// See RunSafely() and llvm_execute_on_thread().
+ bool RunSafelyOnThread(function_ref<void()>, unsigned RequestedStackSize = 0);
bool RunSafelyOnThread(void (*Fn)(void*), void *UserData,
- unsigned RequestedStackSize = 0);
- template<typename Functor>
- bool RunSafelyOnThread(Functor Fn, unsigned RequestedStackSize = 0) {
- FunctorAdaptor<Functor> Adaptor = { Fn };
- return RunSafelyOnThread(Adaptor.fn(), Adaptor.arg(), RequestedStackSize);
+ unsigned RequestedStackSize = 0) {
+ return RunSafelyOnThread([&]() { Fn(UserData); }, RequestedStackSize);
}
/// \brief Explicitly trigger a crash recovery in the current process, and
#ifndef LLVM_TRANSFORMS_UTILS_CTOR_UTILS_H
#define LLVM_TRANSFORMS_UTILS_CTOR_UTILS_H
-#include <functional>
-#include <vector>
+#include "llvm/ADT/STLExtras.h"
namespace llvm {
class Function;
class Module;
-typedef bool (*ShouldRemoveCtor)(void *, Function *);
-
/// Call "ShouldRemove" for every entry in M's global_ctor list and remove the
/// entries for which it returns true. Return true if anything changed.
-bool optimizeGlobalCtorsList(Module &M, ShouldRemoveCtor ShouldRemove,
- void *Context);
+bool optimizeGlobalCtorsList(Module &M,
+ function_ref<bool(Function *)> ShouldRemove);
} // End llvm namespace
#endif
-bool CrashRecoveryContext::RunSafely(void (*Fn)(void*), void *UserData) {
+bool CrashRecoveryContext::RunSafely(function_ref<void()> Fn) {
// If crash recovery is disabled, do nothing.
if (gCrashRecoveryEnabled) {
assert(!Impl && "Crash recovery context already initialized!");
}
}
- Fn(UserData);
+ Fn();
return true;
}
namespace {
struct RunSafelyOnThreadInfo {
- void (*Fn)(void*);
- void *Data;
+ function_ref<void()> Fn;
CrashRecoveryContext *CRC;
bool Result;
};
static void RunSafelyOnThread_Dispatch(void *UserData) {
RunSafelyOnThreadInfo *Info =
reinterpret_cast<RunSafelyOnThreadInfo*>(UserData);
- Info->Result = Info->CRC->RunSafely(Info->Fn, Info->Data);
+ Info->Result = Info->CRC->RunSafely(Info->Fn);
}
-bool CrashRecoveryContext::RunSafelyOnThread(void (*Fn)(void*), void *UserData,
+bool CrashRecoveryContext::RunSafelyOnThread(function_ref<void()> Fn,
unsigned RequestedStackSize) {
- RunSafelyOnThreadInfo Info = { Fn, UserData, this, false };
+ RunSafelyOnThreadInfo Info = { Fn, this, false };
llvm_execute_on_thread(RunSafelyOnThread_Dispatch, &Info, RequestedStackSize);
if (CrashRecoveryContextImpl *CRC = (CrashRecoveryContextImpl *)Impl)
CRC->setSwitchedThread();
bool RemoveUnusedGlobalValue(GlobalValue &GV);
};
+}
/// Returns true if F contains only a single "ret" instruction.
-bool isEmptyFunction(void *Context, Function *F) {
+static bool isEmptyFunction(Function *F) {
BasicBlock &Entry = F->getEntryBlock();
if (Entry.size() != 1 || !isa<ReturnInst>(Entry.front()))
return false;
ReturnInst &RI = cast<ReturnInst>(Entry.front());
return RI.getReturnValue() == NULL;
}
-}
char GlobalDCE::ID = 0;
INITIALIZE_PASS(GlobalDCE, "globaldce",
bool Changed = false;
// Remove empty functions from the global ctors list.
- Changed |= optimizeGlobalCtorsList(M, isEmptyFunction, nullptr);
+ Changed |= optimizeGlobalCtorsList(M, isEmptyFunction);
// Loop over the module, adding globals which are obviously necessary.
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
LocalChange |= OptimizeFunctions(M);
// Optimize global_ctors list.
- LocalChange |= optimizeGlobalCtorsList(M, [](void *C, Function *F) -> bool {
- GlobalOpt *self = static_cast<GlobalOpt *>(C);
- return EvaluateStaticConstructor(F, self->DL, self->TLI);
- }, this);
+ LocalChange |= optimizeGlobalCtorsList(M, [&](Function *F) {
+ return EvaluateStaticConstructor(F, DL, TLI);
+ });
// Optimize non-address-taken globals.
LocalChange |= OptimizeGlobalVars(M);
/// Call "ShouldRemove" for every entry in M's global_ctor list and remove the
/// entries for which it returns true. Return true if anything changed.
-bool optimizeGlobalCtorsList(Module &M, ShouldRemoveCtor ShouldRemove,
- void *Context) {
+bool optimizeGlobalCtorsList(Module &M,
+ function_ref<bool(Function *)> ShouldRemove) {
GlobalVariable *GlobalCtors = findGlobalCtors(M);
if (!GlobalCtors)
return false;
continue;
// If we can evaluate the ctor at compile time, do.
- if (ShouldRemove(Context, F)) {
+ if (ShouldRemove(F)) {
Ctors.erase(Ctors.begin() + i);
MadeChange = true;
--i;
projects / oota-llvm.git / commitdiff