#ifndef SIMGRID_MC_ADDRESS_SPACE_H
#define SIMGRID_MC_ADDRESS_SPACE_H
+#include <cassert>
#include <cstddef>
#include <cstdint>
+#include <cstring>
#include <type_traits>
-#include <xbt/misc.h>
-
-#include "mc_forward.hpp"
+#include "src/mc/mc_forward.hpp"
+#include "src/mc/RemotePtr.hpp"
namespace simgrid {
namespace mc {
-/** Pointer to a remote address-space (process, snapshot)
+/** Process index used when no process is available
+ *
+ * The expected behaviour is that if a process index is needed it will fail.
+ * */
+const int ProcessIndexMissing = -1;
+
+/** Process index used when we don't care about the process index
+ * */
+const int ProcessIndexDisabled = -2;
+
+/** Constant used when any process will do.
*
- * With this we can clearly identify the expected type of an address in the
- * remote process whild avoiding to use native local pointers.
+ * This is is index of the first process.
*/
-template<class T> class remote_ptr {
- std::uint64_t address_;
+const int ProcessIndexAny = 0;
+
+/** Options for read operations
+ *
+ * This is a set of flags managed with bitwise operators. Only the
+ * meaningful operations are defined: addition, conversions to/from
+ * integers are not allowed.
+ */
+class ReadOptions {
+ std::uint32_t value_;
+ constexpr explicit ReadOptions(std::uint32_t value) : value_(value) {}
public:
- remote_ptr() : address_(0) {}
- remote_ptr(std::uint64_t address) : address_(address) {}
- remote_ptr(T* address) : address_((std::uintptr_t)address) {}
- std::uint64_t address() const { return address_; }
- operator bool() const
+ constexpr ReadOptions() : value_(0) {}
+
+ constexpr operator bool() const { return value_ != 0; }
+ constexpr bool operator!() const { return value_ == 0; }
+
+ constexpr ReadOptions operator|(ReadOptions const& that) const
{
- return address_;
+ return ReadOptions(value_ | that.value_);
}
- bool operator!() const
+ constexpr ReadOptions operator&(ReadOptions const& that) const
{
- return !address_;
+ return ReadOptions(value_ & that.value_);
}
- operator remote_ptr<void>() const
+ constexpr ReadOptions operator^(ReadOptions const& that) const
{
- return remote_ptr<void>(address_);
+ return ReadOptions(value_ ^ that.value_);
}
- remote_ptr<T> operator+(std::uint64_t n) const
+ constexpr ReadOptions operator~() const
{
- return remote_ptr<T>(address_ + n * sizeof(T));
+ return ReadOptions(~value_);
}
- remote_ptr<T> operator-(std::uint64_t n) const
+
+ ReadOptions& operator|=(ReadOptions const& that)
{
- return remote_ptr<T>(address_ - n * sizeof(T));
+ value_ |= that.value_;
+ return *this;
}
- remote_ptr<T>& operator+=(std::uint64_t n) const
+ ReadOptions& operator&=(ReadOptions const& that)
{
- address_ += n * sizeof(T);
+ value_ &= that.value_;
return *this;
}
- remote_ptr<T>& operator-=(std::uint64_t n) const
+ ReadOptions& operator^=(ReadOptions const& that)
{
- address_ -= n * sizeof(T);
+ value_ &= that.value_;
return *this;
}
-};
-
-template<class X, class Y>
-bool operator<(remote_ptr<X> const& x, remote_ptr<Y> const& y)
-{
- return x.address() < y.address();
-}
-
-template<class X, class Y>
-bool operator>(remote_ptr<X> const& x, remote_ptr<Y> const& y)
-{
- return x.address() > y.address();
-}
-
-template<class X, class Y>
-bool operator>=(remote_ptr<X> const& x, remote_ptr<Y> const& y)
-{
- return x.address() >= y.address();
-}
-template<class X, class Y>
-bool operator<=(remote_ptr<X> const& x, remote_ptr<Y> const& y)
-{
- return x.address() <= y.address();
-}
+ /** Copy the data to the given buffer */
+ static constexpr ReadOptions none() { return ReadOptions(0); }
-template<class X, class Y>
-bool operator==(remote_ptr<X> const& x, remote_ptr<Y> const& y)
-{
- return x.address() == y.address();
-}
-
-template<class X, class Y>
-bool operator!=(remote_ptr<X> const& x, remote_ptr<Y> const& y)
-{
- return x.address() != y.address();
-}
-
-template<class T> inline
-remote_ptr<T> remote(T *p)
-{
- return remote_ptr<T>(p);
-}
-
-template<class T=void> inline
-remote_ptr<T> remote(uint64_t p)
-{
- return remote_ptr<T>(p);
-}
+ /** Allows to return a pointer to another buffer where the data is
+ * available instead of copying the data into the buffer
+ */
+ static constexpr ReadOptions lazy() { return ReadOptions(1); }
+};
-/** Process index used when no process is available
+/** A value from another process
*
- * The expected behaviour is that if a process index is needed it will fail.
- * */
-const int ProcessIndexMissing = -1;
-
-/** Process index used when we don't care about the process index
- * */
-const int ProcessIndexDisabled = -2;
-
-/** Constant used when any process will do.
+ * This represents a value from another process:
*
- * This is is index of the first process.
+ * * constructor/destructor are disabled;
+ *
+ * * raw memory copy (std::memcpy) is used to copy Remote<T>;
+ *
+ * * raw memory comparison is used to compare them;
+ *
+ * * when T is a trivial type, Remote is convertible to a T.
+ *
+ * We currently only handle the case where the type has the same layout
+ * in the current process and in the target process: we don't handle
+ * cross-architecture (such as 32-bit/64-bit access).
*/
-const int ProcessIndexAny = 0;
+template<class T>
+class Remote {
+private:
+ // If we use a union, it won't work with abstract types:
+ char buffer[sizeof(T)];
+public:
+ // HACK, some code currently cast this to T* which is **not** legal.
+ void* data() { return buffer; }
+ const void* data() const { return buffer; }
+ constexpr std::size_t size() const { return sizeof(T); }
+ operator T() const {
+ static_assert(std::is_trivial<T>::value, "Cannot convert non trivial type");
+ T res;
+ std::memcpy(&res, buffer, sizeof(T));
+ return res;
+ }
+ Remote() {}
+ Remote(T const& x)
+ {
+ std::memcpy(&x, buffer, sizeof(T));
+ }
+ Remote& operator=(T const& x)
+ {
+ std::memcpy(&x, buffer, sizeof(T));
+ }
+};
+/** A given state of a given process (abstract base class)
+ *
+ * Currently, this might either be:
+ *
+ * * the current state of an existing process;
+ *
+ * * a snapshot.
+ */
class AddressSpace {
private:
Process* process_;
public:
- enum ReadMode {
- Normal,
- /** Allows the `read_bytes` to return a pointer to another buffer
- * where the data ins available instead of copying the data into the buffer
- */
- Lazy
- };
AddressSpace(Process* process) : process_(process) {}
virtual ~AddressSpace();
- simgrid::mc::Process* process() { return process_; }
+ simgrid::mc::Process* process() const { return process_; }
+
+ /** Read data from the address space
+ *
+ * @param buffer target buffer for the data
+ * @param size number of bytes
+ * @param address remote source address of the data
+ * @param process_index which process (used for SMPI privatization)
+ * @param options
+ */
virtual const void* read_bytes(void* buffer, std::size_t size,
- remote_ptr<void> address, int process_index = ProcessIndexAny,
- ReadMode mode = Normal) const = 0;
+ RemotePtr<void> address, int process_index = ProcessIndexAny,
+ ReadOptions options = ReadOptions::none()) const = 0;
+ /** Read a given data structure from the address space */
template<class T> inline
- void read(T *buffer, remote_ptr<T> ptr, int process_index = ProcessIndexAny)
+ void read(T *buffer, RemotePtr<T> ptr, int process_index = ProcessIndexAny)
{
this->read_bytes(buffer, sizeof(T), ptr, process_index);
}
template<class T> inline
- T read(remote_ptr<T> ptr, int process_index = ProcessIndexMissing)
+ void read(Remote<T>& buffer, RemotePtr<T> ptr, int process_index = ProcessIndexAny)
{
- static_assert(std::is_trivial<T>::value, "Cannot read a non-trivial type");
- T res;
- return *(T*)this->read_bytes(&res, sizeof(T), ptr, process_index);
+ this->read_bytes(buffer.data(), sizeof(T), ptr, process_index);
+ }
+
+ /** Read a given data structure from the address space */
+ template<class T> inline
+ Remote<T> read(RemotePtr<T> ptr, int process_index = ProcessIndexMissing)
+ {
+ Remote<T> res;
+ this->read_bytes(&res, sizeof(T), ptr, process_index);
+ return res;
}
};
