1 files changed, 52 insertions, 5 deletions

diff --git a/lib/Support/Windows/Memory.inc b/lib/Support/Windows/Memory.inc
index 9f69e73..fcc7283 100644
--- a/lib/Support/Windows/Memory.inc
+++ b/lib/Support/Windows/Memory.inc
@@ -32,11 +32,16 @@ MemoryBlock Memory::AllocateRWX(size_t NumBytes,
   static const size_t pageSize = Process::GetPageSize();
   size_t NumPages = (NumBytes+pageSize-1)/pageSize;
 
-  //FIXME: support NearBlock if ever needed on Win64.
+  PVOID start = NearBlock ? static_cast<unsigned char *>(NearBlock->base()) +
+                                NearBlock->size() : NULL;
 
-  void *pa = VirtualAlloc(NULL, NumPages*pageSize, MEM_COMMIT,
+  void *pa = VirtualAlloc(start, NumPages*pageSize, MEM_RESERVE | MEM_COMMIT,
                   PAGE_EXECUTE_READWRITE);
   if (pa == NULL) {
+    if (NearBlock) {
+      // Try again without the NearBlock hint
+      return AllocateRWX(NumBytes, NULL, ErrMsg);
+    }
     MakeErrMsg(ErrMsg, "Can't allocate RWX Memory: ");
     return MemoryBlock();
   }
@@ -54,20 +59,62 @@ bool Memory::ReleaseRWX(MemoryBlock &M, std::string *ErrMsg) {
   return false;
 }
 
+static DWORD getProtection(const void *addr) {
+  MEMORY_BASIC_INFORMATION info;
+  if (sizeof(info) == ::VirtualQuery(addr, &info, sizeof(info))) {
+    return info.Protect;
+  }
+  return 0;
+}
+
 bool Memory::setWritable(MemoryBlock &M, std::string *ErrMsg) {
+  if (!setRangeWritable(M.Address, M.Size)) {
+    return MakeErrMsg(ErrMsg, "Cannot set memory to writeable: ");
+  }
   return true;
 }
 
 bool Memory::setExecutable(MemoryBlock &M, std::string *ErrMsg) {
-  return false;
+  if (!setRangeExecutable(M.Address, M.Size)) {
+    return MakeErrMsg(ErrMsg, "Cannot set memory to executable: ");
+  }
+  return true;
 }
 
 bool Memory::setRangeWritable(const void *Addr, size_t Size) {
-  return true;
+  DWORD prot = getProtection(Addr);
+  if (!prot)
+    return false;
+
+  if (prot == PAGE_EXECUTE || prot == PAGE_EXECUTE_READ) {
+    prot = PAGE_EXECUTE_READWRITE;
+  } else if (prot == PAGE_NOACCESS || prot == PAGE_READONLY) {
+    prot = PAGE_READWRITE;
+  }
+
+  DWORD oldProt;
+  sys::Memory::InvalidateInstructionCache(Addr, Size);
+  return ::VirtualProtect(const_cast<LPVOID>(Addr), Size, prot, &oldProt)
+            == TRUE;
 }
 
 bool Memory::setRangeExecutable(const void *Addr, size_t Size) {
-  return false;
+  DWORD prot = getProtection(Addr);
+  if (!prot)
+    return false;
+
+  if (prot == PAGE_NOACCESS) {
+    prot = PAGE_EXECUTE;
+  } else if (prot == PAGE_READONLY) {
+    prot = PAGE_EXECUTE_READ;
+  } else if (prot == PAGE_READWRITE) {
+    prot = PAGE_EXECUTE_READWRITE;
+  }
+
+  DWORD oldProt;
+  sys::Memory::InvalidateInstructionCache(Addr, Size);
+  return ::VirtualProtect(const_cast<LPVOID>(Addr), Size, prot, &oldProt)
+            == TRUE;
 }
 
 }