[Orc] Move SectionMemoryManager's implementation from MCJIT to ExecutionEngine.

This is a more sensible home for SectionMemoryManager, and allows the implementation
to be shared between Orc and MCJIT.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228427 91177308-0d34-0410-b5e6-96231b3b80d8

lib/ExecutionEngine/SectionMemoryManager.cpp

@@ -0,0 +1,178 @@
+//===- SectionMemoryManager.cpp - Memory manager for MCJIT/RtDyld *- C++ -*-==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the section-based memory manager used by the MCJIT
+// execution engine and RuntimeDyld
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Config/config.h"
+#include "llvm/ExecutionEngine/SectionMemoryManager.h"
+#include "llvm/Support/MathExtras.h"
+
+namespace llvm {
+
+uint8_t *SectionMemoryManager::allocateDataSection(uintptr_t Size,
+                                                   unsigned Alignment,
+                                                   unsigned SectionID,
+                                                   StringRef SectionName,
+                                                   bool IsReadOnly) {
+  if (IsReadOnly)
+    return allocateSection(RODataMem, Size, Alignment);
+  return allocateSection(RWDataMem, Size, Alignment);
+}
+
+uint8_t *SectionMemoryManager::allocateCodeSection(uintptr_t Size,
+                                                   unsigned Alignment,
+                                                   unsigned SectionID,
+                                                   StringRef SectionName) {
+  return allocateSection(CodeMem, Size, Alignment);
+}
+
+uint8_t *SectionMemoryManager::allocateSection(MemoryGroup &MemGroup,
+                                               uintptr_t Size,
+                                               unsigned Alignment) {
+  if (!Alignment)
+    Alignment = 16;
+
+  assert(!(Alignment & (Alignment - 1)) && "Alignment must be a power of two.");
+
+  uintptr_t RequiredSize = Alignment * ((Size + Alignment - 1)/Alignment + 1);
+  uintptr_t Addr = 0;
+
+  // Look in the list of free memory regions and use a block there if one
+  // is available.
+  for (int i = 0, e = MemGroup.FreeMem.size(); i != e; ++i) {
+    sys::MemoryBlock &MB = MemGroup.FreeMem[i];
+    if (MB.size() >= RequiredSize) {
+      Addr = (uintptr_t)MB.base();
+      uintptr_t EndOfBlock = Addr + MB.size();
+      // Align the address.
+      Addr = (Addr + Alignment - 1) & ~(uintptr_t)(Alignment - 1);
+      // Store cutted free memory block.
+      MemGroup.FreeMem[i] = sys::MemoryBlock((void*)(Addr + Size),
+                                             EndOfBlock - Addr - Size);
+      return (uint8_t*)Addr;
+    }
+  }
+
+  // No pre-allocated free block was large enough. Allocate a new memory region.
+  // Note that all sections get allocated as read-write.  The permissions will
+  // be updated later based on memory group.
+  //
+  // FIXME: It would be useful to define a default allocation size (or add
+  // it as a constructor parameter) to minimize the number of allocations.
+  //
+  // FIXME: Initialize the Near member for each memory group to avoid
+  // interleaving.
+  std::error_code ec;
+  sys::MemoryBlock MB = sys::Memory::allocateMappedMemory(RequiredSize,
+                                                          &MemGroup.Near,
+                                                          sys::Memory::MF_READ |
+                                                            sys::Memory::MF_WRITE,
+                                                          ec);
+  if (ec) {
+    // FIXME: Add error propagation to the interface.
+    return nullptr;
+  }
+
+  // Save this address as the basis for our next request
+  MemGroup.Near = MB;
+
+  MemGroup.AllocatedMem.push_back(MB);
+  Addr = (uintptr_t)MB.base();
+  uintptr_t EndOfBlock = Addr + MB.size();
+
+  // Align the address.
+  Addr = (Addr + Alignment - 1) & ~(uintptr_t)(Alignment - 1);
+
+  // The allocateMappedMemory may allocate much more memory than we need. In
+  // this case, we store the unused memory as a free memory block.
+  unsigned FreeSize = EndOfBlock-Addr-Size;
+  if (FreeSize > 16)
+    MemGroup.FreeMem.push_back(sys::MemoryBlock((void*)(Addr + Size), FreeSize));
+
+  // Return aligned address
+  return (uint8_t*)Addr;
+}
+
+bool SectionMemoryManager::finalizeMemory(std::string *ErrMsg)
+{
+  // FIXME: Should in-progress permissions be reverted if an error occurs?
+  std::error_code ec;
+
+  // Don't allow free memory blocks to be used after setting protection flags.
+  CodeMem.FreeMem.clear();
+
+  // Make code memory executable.
+  ec = applyMemoryGroupPermissions(CodeMem,
+                                   sys::Memory::MF_READ | sys::Memory::MF_EXEC);
+  if (ec) {
+    if (ErrMsg) {
+      *ErrMsg = ec.message();
+    }
+    return true;
+  }
+
+  // Don't allow free memory blocks to be used after setting protection flags.
+  RODataMem.FreeMem.clear();
+
+  // Make read-only data memory read-only.
+  ec = applyMemoryGroupPermissions(RODataMem,
+                                   sys::Memory::MF_READ | sys::Memory::MF_EXEC);
+  if (ec) {
+    if (ErrMsg) {
+      *ErrMsg = ec.message();
+    }
+    return true;
+  }
+
+  // Read-write data memory already has the correct permissions
+
+  // Some platforms with separate data cache and instruction cache require
+  // explicit cache flush, otherwise JIT code manipulations (like resolved
+  // relocations) will get to the data cache but not to the instruction cache.
+  invalidateInstructionCache();
+
+  return false;
+}
+
+std::error_code
+SectionMemoryManager::applyMemoryGroupPermissions(MemoryGroup &MemGroup,
+                                                  unsigned Permissions) {
+
+  for (int i = 0, e = MemGroup.AllocatedMem.size(); i != e; ++i) {
+    std::error_code ec;
+    ec =
+        sys::Memory::protectMappedMemory(MemGroup.AllocatedMem[i], Permissions);
+    if (ec) {
+      return ec;
+    }
+  }
+
+  return std::error_code();
+}
+
+void SectionMemoryManager::invalidateInstructionCache() {
+  for (int i = 0, e = CodeMem.AllocatedMem.size(); i != e; ++i)
+    sys::Memory::InvalidateInstructionCache(CodeMem.AllocatedMem[i].base(),
+                                            CodeMem.AllocatedMem[i].size());
+}
+
+SectionMemoryManager::~SectionMemoryManager() {
+  for (unsigned i = 0, e = CodeMem.AllocatedMem.size(); i != e; ++i)
+    sys::Memory::releaseMappedMemory(CodeMem.AllocatedMem[i]);
+  for (unsigned i = 0, e = RWDataMem.AllocatedMem.size(); i != e; ++i)
+    sys::Memory::releaseMappedMemory(RWDataMem.AllocatedMem[i]);
+  for (unsigned i = 0, e = RODataMem.AllocatedMem.size(); i != e; ++i)
+    sys::Memory::releaseMappedMemory(RODataMem.AllocatedMem[i]);
+}
+
+} // namespace llvm
+