[Orc] Add support for emitting indirect stubs directly into the JIT target's

[oota-llvm.git] / include / llvm / ExecutionEngine / Orc / OrcTargetSupport.h

diff --git a/include/llvm/ExecutionEngine/Orc/OrcTargetSupport.h b/include/llvm/ExecutionEngine/Orc/OrcTargetSupport.h
index 309f5a96090ef313a472a1973db67caae1286917..bf0e41e9f1fe38b24e8b79a69d5f6a78af04987e 100644 (file)
--- a/include/llvm/ExecutionEngine/Orc/OrcTargetSupport.h
+++ b/include/llvm/ExecutionEngine/Orc/OrcTargetSupport.h
@@ -9,12 +9,17 @@
 //
 // Target specific code for Orc, e.g. callback assembly.
 //
+// Target classes should be part of the JIT *target* process, not the host
+// process (except where you're doing hosted JITing and the two are one and the
+// same).
+//
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_EXECUTIONENGINE_ORC_ORCTARGETSUPPORT_H
 #define LLVM_EXECUTIONENGINE_ORC_ORCTARGETSUPPORT_H
 
 #include "IndirectionUtils.h"
+#include "llvm/Support/Memory.h"
 
 namespace llvm {
 namespace orc {
@@ -45,6 +50,46 @@ public:
                                                     unsigned NumCalls,
                                                     unsigned StartIndex = 0);
 
+  /// @brief Provide information about stub blocks generated by the
+  ///        makeIndirectStubsBlock function.
+  class IndirectStubsInfo {
+    friend class OrcX86_64;
+  public:
+    const static unsigned StubSize = 8;
+    const static unsigned PtrSize = 8;
+
+    IndirectStubsInfo() : NumStubs(0) {}
+    ~IndirectStubsInfo();
+
+    /// @brief Number of stubs in this block.
+    unsigned getNumStubs() const { return NumStubs; }
+
+    /// @brief Get a pointer to the stub at the given index, which must be in
+    ///        the range 0 .. getNumStubs() - 1.
+    void* getStub(unsigned Idx) const {
+      return static_cast<uint64_t*>(StubsBlock.base()) + Idx;
+    }
+
+    /// @brief Get a pointer to the implementation-pointer at the given index,
+    ///        which must be in the range 0 .. getNumStubs() - 1.
+    void** getPtr(unsigned Idx) const {
+      return static_cast<void**>(PtrsBlock.base()) + Idx;
+    }
+  private:
+    unsigned NumStubs;
+    sys::MemoryBlock StubsBlock;
+    sys::MemoryBlock PtrsBlock;
+  };
+
+  /// @brief Emit at least MinStubs worth of indirect call stubs, rounded out to
+  ///        the nearest page size.
+  ///
+  ///   E.g. Asking for 4 stubs on x86-64, where stubs are 8-bytes, with 4k
+  /// pages will return a block of 512 stubs (4096 / 8 = 512). Asking for 513
+  /// will return a block of 1024 (2-pages worth).
+  static std::error_code emitIndirectStubsBlock(IndirectStubsInfo &StubsInfo,
+                                                unsigned MinStubs,
+                                                void *InitialPtrVal);
 };
 
 } // End namespace orc.