From cce6c297c54b4c9c8615c77e97cd64e70812ea60 Mon Sep 17 00:00:00 2001
From: Jim Grosbach <grosbach@apple.com>
Date: Fri, 3 Oct 2008 16:17:20 +0000
Subject: 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
---
 lib/ExecutionEngine/JIT/JITEmitter.cpp       | 12 +++++++++++-
 lib/ExecutionEngine/JIT/JITMemoryManager.cpp | 15 +++++++++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)

(limited to 'lib/ExecutionEngine')

diff --git a/lib/ExecutionEngine/JIT/JITEmitter.cpp b/lib/ExecutionEngine/JIT/JITEmitter.cpp
index ffaeb1c..a90a6a5 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 804e88d..0ffc779 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]);
+    }
   };
 }
 
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