On Darwin ARM, memory needs special handling to do JIT. This patch expands

this handling to work properly for modifying stub functions, relocations
back to entry points after JIT compilation, etc..


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57013 91177308-0d34-0410-b5e6-96231b3b80d8

6 files changed, 66 insertions, 15 deletions

diff --git a/include/llvm/ExecutionEngine/JITMemoryManager.h b/include/llvm/ExecutionEngine/JITMemoryManager.h
index e1f2763e1d..0d79d14d71 100644
--- a/include/llvm/ExecutionEngine/JITMemoryManager.h
+++ b/include/llvm/ExecutionEngine/JITMemoryManager.h
@@ -35,6 +35,14 @@ public:
   /// JIT Memory Manager if the client does not provide one to the JIT.
   static JITMemoryManager *CreateDefaultMemManager();
   
+  /// setMemoryWritable - When code generation is in progress,
+  /// the code pages may need permissions changed.
+  virtual void setMemoryWritable(void) = 0;
+
+  /// setMemoryExecutable - When code generation is done and we're ready to
+  /// start execution, the code pages may need permissions changed.
+  virtual void setMemoryExecutable(void) = 0;
+
   //===--------------------------------------------------------------------===//
   // Global Offset Table Management
   //===--------------------------------------------------------------------===//
diff --git a/include/llvm/System/Memory.h b/include/llvm/System/Memory.h
index 86895e2317..4d0828b575 100644
--- a/include/llvm/System/Memory.h
+++ b/include/llvm/System/Memory.h
@@ -70,10 +70,15 @@ namespace sys {
     /// platforms.
     static void InvalidateInstructionCache(const void *Addr, size_t Len);
 
-    /// SetRXPrivilege - Before the JIT can run a block of code, it has to be
+    /// setExecutable - Before the JIT can run a block of code, it has to be
     /// given read and executable privilege. Return true if it is already r-x
     /// or the system is able to change its previlege.
-    static bool SetRXPrivilege(const void *Addr, size_t Size);
+    static bool setExecutable (MemoryBlock &M, std::string *ErrMsg = 0);
+
+    /// setWritable - When adding to a block of code, the JIT may need
+    /// to mark a block of code as RW since the protections are on page
+    /// boundaries, and the JIT internal allocations are not page aligned.
+    static bool setWritable (MemoryBlock &M, std::string *ErrMsg = 0);
   };
 }
 }
diff --git a/lib/ExecutionEngine/JIT/JITEmitter.cpp b/lib/ExecutionEngine/JIT/JITEmitter.cpp
index ffaeb1c4ea..a90a6a52fa 100644
--- a/lib/ExecutionEngine/JIT/JITEmitter.cpp
+++ b/lib/ExecutionEngine/JIT/JITEmitter.cpp
@@ -560,6 +560,10 @@ namespace {
       if (ExceptionHandling) DE->setModuleInfo(Info);
     }
 
+    void setMemoryExecutable(void) {
+      MemMgr->setMemoryExecutable();
+    }
+
   private:
     void *getPointerToGlobal(GlobalValue *GV, void *Reference, bool NoNeedStub);
     void *getPointerToGVLazyPtr(GlobalValue *V, void *Reference,
@@ -791,6 +795,8 @@ unsigned JITEmitter::GetSizeOfGlobalsInBytes(MachineFunction &MF) {
 
 void JITEmitter::startFunction(MachineFunction &F) {
   uintptr_t ActualSize = 0;
+  // Set the memory writable, if it's not already
+  MemMgr->setMemoryWritable();
   if (MemMgr->NeedsExactSize()) {
     DOUT << "ExactSize\n";
     const TargetInstrInfo* TII = F.getTarget().getInstrInfo();
@@ -938,7 +944,7 @@ bool JITEmitter::finishFunction(MachineFunction &F) {
   Relocations.clear();
 
   // Mark code region readable and executable if it's not so already.
-  sys::Memory::SetRXPrivilege(FnStart, FnEnd-FnStart);
+  MemMgr->setMemoryExecutable();
 
 #ifndef NDEBUG
   {
@@ -1086,6 +1092,10 @@ void JITEmitter::startFunctionStub(const GlobalValue* F, unsigned StubSize,
 
 void *JITEmitter::finishFunctionStub(const GlobalValue* F) {
   NumBytes += getCurrentPCOffset();
+
+  // Invalidate the icache if necessary.
+  sys::Memory::InvalidateInstructionCache(BufferBegin, NumBytes);
+
   std::swap(SavedBufferBegin, BufferBegin);
   BufferEnd = SavedBufferEnd;
   CurBufferPtr = SavedCurBufferPtr;
diff --git a/lib/ExecutionEngine/JIT/JITMemoryManager.cpp b/lib/ExecutionEngine/JIT/JITMemoryManager.cpp
index 804e88df4c..0ffc779901 100644
--- a/lib/ExecutionEngine/JIT/JITMemoryManager.cpp
+++ b/lib/ExecutionEngine/JIT/JITMemoryManager.cpp
@@ -365,6 +365,21 @@ namespace {
       // Finally, remove this entry from TableBlocks.
       TableBlocks.erase(I);
     }
+
+    /// setMemoryWritable - When code generation is in progress,
+    /// the code pages may need permissions changed.
+    void setMemoryWritable(void)
+    {
+      for (unsigned i = 0, e = Blocks.size(); i != e; ++i)
+        sys::Memory::setWritable(Blocks[i]);
+    }
+    /// setMemoryExecutable - When code generation is done and we're ready to
+    /// start execution, the code pages may need permissions changed.
+    void setMemoryExecutable(void)
+    {
+      for (unsigned i = 0, e = Blocks.size(); i != e; ++i)
+        sys::Memory::setExecutable(Blocks[i]);
+    }
   };
 }
 
diff --git a/lib/System/Memory.cpp b/lib/System/Memory.cpp
index 2fc6a23a3a..3660bcb1a4 100644
--- a/lib/System/Memory.cpp
+++ b/lib/System/Memory.cpp
@@ -58,14 +58,3 @@ void llvm::sys::Memory::InvalidateInstructionCache(const void *Addr,
 #endif  // end PPC
 
 }
-
-bool llvm::sys::Memory::SetRXPrivilege(const void *Addr, size_t Size) {
-#if defined(__APPLE__) && defined(__arm__)
-  kern_return_t kr = vm_protect(mach_task_self(), (vm_address_t)Addr,
-                                (vm_size_t)Size, 0,
-                                VM_PROT_READ | VM_PROT_EXECUTE | VM_PROT_COPY);
-  return KERN_SUCCESS == kr;
-#else
-  return true;
-#endif
-}
diff --git a/lib/System/Unix/Memory.inc b/lib/System/Unix/Memory.inc
index cf0157d577..646311d8cd 100644
--- a/lib/System/Unix/Memory.inc
+++ b/lib/System/Unix/Memory.inc
@@ -76,7 +76,7 @@ llvm::sys::Memory::AllocateRWX(unsigned NumBytes, const MemoryBlock* NearBlock,
                                 (vm_size_t)(pageSize*NumPages), 0,
                                 VM_PROT_READ | VM_PROT_EXECUTE | VM_PROT_COPY);
   if (KERN_SUCCESS != kr) {
-    MakeErrMsg(ErrMsg, "vm_protect max RWX failed\n");
+    MakeErrMsg(ErrMsg, "vm_protect max RX failed\n");
     return sys::MemoryBlock();
   }
 
@@ -103,3 +103,27 @@ bool llvm::sys::Memory::ReleaseRWX(MemoryBlock &M, std::string *ErrMsg) {
   return false;
 }
 
+bool llvm::sys::Memory::setWritable (MemoryBlock &M, std::string *ErrMsg) {
+#if defined(__APPLE__) && defined(__arm__)
+  if (M.Address == 0 || M.Size == 0) return false;
+  sys::Memory::InvalidateInstructionCache(M.Address, M.Size);
+  kern_return_t kr = vm_protect(mach_task_self(), (vm_address_t)M.Address,
+    (vm_size_t)M.Size, 0, VM_PROT_READ | VM_PROT_WRITE);
+  return KERN_SUCCESS == kr;
+#else
+  return true;
+#endif
+}
+
+bool llvm::sys::Memory::setExecutable (MemoryBlock &M, std::string *ErrMsg) {
+#if defined(__APPLE__) && defined(__arm__)
+  if (M.Address == 0 || M.Size == 0) return false;
+  sys::Memory::InvalidateInstructionCache(M.Address, M.Size);
+  kern_return_t kr = vm_protect(mach_task_self(), (vm_address_t)M.Address,
+    (vm_size_t)M.Size, 0, VM_PROT_READ | VM_PROT_EXECUTE | VM_PROT_COPY);
+  return KERN_SUCCESS == kr;
+#else
+  return false;
+#endif
+}
+