1 files changed, 268 insertions, 0 deletions
diff --git a/llvm/lib/Support/Unix/Memory.inc b/llvm/lib/Support/Unix/Memory.inc
new file mode 100644
index 000000000000..05f8e32896fa
--- /dev/null
+++ b/llvm/lib/Support/Unix/Memory.inc
@@ -0,0 +1,268 @@
+//===- Unix/Memory.cpp - Generic UNIX System Configuration ------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines some functions for various memory management utilities.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Unix.h"
+#include "llvm/Config/config.h"
+#include "llvm/Support/DataTypes.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/Process.h"
+
+#ifdef HAVE_SYS_MMAN_H
+#include <sys/mman.h>
+#endif
+
+#ifdef __APPLE__
+#include <mach/mach.h>
+#endif
+
+#ifdef __Fuchsia__
+#include <zircon/syscalls.h>
+#endif
+
+#if defined(__mips__)
+#  if defined(__OpenBSD__)
+#    include <mips64/sysarch.h>
+#  elif !defined(__FreeBSD__)
+#    include <sys/cachectl.h>
+#  endif
+#endif
+
+#if defined(__APPLE__)
+extern "C" void sys_icache_invalidate(const void *Addr, size_t len);
+#else
+extern "C" void __clear_cache(void *, void*);
+#endif
+
+namespace {
+
+int getPosixProtectionFlags(unsigned Flags) {
+  switch (Flags & llvm::sys::Memory::MF_RWE_MASK) {
+  case llvm::sys::Memory::MF_READ:
+    return PROT_READ;
+  case llvm::sys::Memory::MF_WRITE:
+    return PROT_WRITE;
+  case llvm::sys::Memory::MF_READ|llvm::sys::Memory::MF_WRITE:
+    return PROT_READ | PROT_WRITE;
+  case llvm::sys::Memory::MF_READ|llvm::sys::Memory::MF_EXEC:
+    return PROT_READ | PROT_EXEC;
+  case llvm::sys::Memory::MF_READ | llvm::sys::Memory::MF_WRITE |
+      llvm::sys::Memory::MF_EXEC:
+    return PROT_READ | PROT_WRITE | PROT_EXEC;
+  case llvm::sys::Memory::MF_EXEC:
+#if (defined(__FreeBSD__) || defined(__POWERPC__) || defined (__ppc__) || \
+     defined(_POWER) || defined(_ARCH_PPC))
+    // On PowerPC, having an executable page that has no read permission
+    // can have unintended consequences.  The function InvalidateInstruction-
+    // Cache uses instructions dcbf and icbi, both of which are treated by
+    // the processor as loads.  If the page has no read permissions,
+    // executing these instructions will result in a segmentation fault.
+    return PROT_READ | PROT_EXEC;
+#else
+    return PROT_EXEC;
+#endif
+  default:
+    llvm_unreachable("Illegal memory protection flag specified!");
+  }
+  // Provide a default return value as required by some compilers.
+  return PROT_NONE;
+}
+
+} // anonymous namespace
+
+namespace llvm {
+namespace sys {
+
+MemoryBlock
+Memory::allocateMappedMemory(size_t NumBytes,
+                             const MemoryBlock *const NearBlock,
+                             unsigned PFlags,
+                             std::error_code &EC) {
+  EC = std::error_code();
+  if (NumBytes == 0)
+    return MemoryBlock();
+
+  // On platforms that have it, we can use MAP_ANON to get a memory-mapped
+  // page without file backing, but we need a fallback of opening /dev/zero
+  // for strictly POSIX platforms instead.
+  int fd;
+#if defined(MAP_ANON)
+  fd = -1;
+#else
+  fd = open("/dev/zero", O_RDWR);
+  if (fd == -1) {
+    EC = std::error_code(errno, std::generic_category());
+    return MemoryBlock();
+  }
+#endif
+
+  int MMFlags = MAP_PRIVATE;
+#if defined(MAP_ANON)
+  MMFlags |= MAP_ANON;
+#endif
+  int Protect = getPosixProtectionFlags(PFlags);
+
+#if defined(__NetBSD__) && defined(PROT_MPROTECT)
+  Protect |= PROT_MPROTECT(PROT_READ | PROT_WRITE | PROT_EXEC);
+#endif
+
+  // Use any near hint and the page size to set a page-aligned starting address
+  uintptr_t Start = NearBlock ? reinterpret_cast<uintptr_t>(NearBlock->base()) +
+                                      NearBlock->allocatedSize() : 0;
+  static const size_t PageSize = Process::getPageSizeEstimate();
+  const size_t NumPages = (NumBytes+PageSize-1)/PageSize;
+
+  if (Start && Start % PageSize)
+    Start += PageSize - Start % PageSize;
+
+  // FIXME: Handle huge page requests (MF_HUGE_HINT).
+  void *Addr = ::mmap(reinterpret_cast<void *>(Start), PageSize*NumPages, Protect,
+                      MMFlags, fd, 0);
+  if (Addr == MAP_FAILED) {
+    if (NearBlock) { //Try again without a near hint
+#if !defined(MAP_ANON)
+      close(fd);
+#endif
+      return allocateMappedMemory(NumBytes, nullptr, PFlags, EC);
+    }
+
+    EC = std::error_code(errno, std::generic_category());
+#if !defined(MAP_ANON)
+    close(fd);
+#endif
+    return MemoryBlock();
+  }
+
+#if !defined(MAP_ANON)
+  close(fd);
+#endif
+
+  MemoryBlock Result;
+  Result.Address = Addr;
+  Result.AllocatedSize = PageSize*NumPages;
+  Result.Flags = PFlags;
+
+  // Rely on protectMappedMemory to invalidate instruction cache.
+  if (PFlags & MF_EXEC) {
+    EC = Memory::protectMappedMemory (Result, PFlags);
+    if (EC != std::error_code())
+      return MemoryBlock();
+  }
+
+  return Result;
+}
+
+std::error_code
+Memory::releaseMappedMemory(MemoryBlock &M) {
+  if (M.Address == nullptr || M.AllocatedSize == 0)
+    return std::error_code();
+
+  if (0 != ::munmap(M.Address, M.AllocatedSize))
+    return std::error_code(errno, std::generic_category());
+
+  M.Address = nullptr;
+  M.AllocatedSize = 0;
+
+  return std::error_code();
+}
+
+std::error_code
+Memory::protectMappedMemory(const MemoryBlock &M, unsigned Flags) {
+  static const Align PageSize = Align(Process::getPageSizeEstimate());
+  if (M.Address == nullptr || M.AllocatedSize == 0)
+    return std::error_code();
+
+  if (!Flags)
+    return std::error_code(EINVAL, std::generic_category());
+
+  int Protect = getPosixProtectionFlags(Flags);
+  uintptr_t Start = alignAddr((const uint8_t *)M.Address - PageSize.value() + 1, PageSize);
+  uintptr_t End = alignAddr((const uint8_t *)M.Address + M.AllocatedSize, PageSize);
+
+  bool InvalidateCache = (Flags & MF_EXEC);
+
+#if defined(__arm__) || defined(__aarch64__)
+  // Certain ARM implementations treat icache clear instruction as a memory read,
+  // and CPU segfaults on trying to clear cache on !PROT_READ page.  Therefore we need
+  // to temporarily add PROT_READ for the sake of flushing the instruction caches.
+  if (InvalidateCache && !(Protect & PROT_READ)) {
+    int Result = ::mprotect((void *)Start, End - Start, Protect | PROT_READ);
+    if (Result != 0)
+      return std::error_code(errno, std::generic_category());
+
+    Memory::InvalidateInstructionCache(M.Address, M.AllocatedSize);
+    InvalidateCache = false;
+  }
+#endif
+
+  int Result = ::mprotect((void *)Start, End - Start, Protect);
+
+  if (Result != 0)
+    return std::error_code(errno, std::generic_category());
+
+  if (InvalidateCache)
+    Memory::InvalidateInstructionCache(M.Address, M.AllocatedSize);
+
+  return std::error_code();
+}
+
+/// InvalidateInstructionCache - Before the JIT can run a block of code
+/// that has been emitted it must invalidate the instruction cache on some
+/// platforms.
+void Memory::InvalidateInstructionCache(const void *Addr,
+                                        size_t Len) {
+
+// icache invalidation for PPC and ARM.
+#if defined(__APPLE__)
+
+#  if (defined(__POWERPC__) || defined (__ppc__) || \
+       defined(_POWER) || defined(_ARCH_PPC) || defined(__arm__) || \
+       defined(__arm64__))
+  sys_icache_invalidate(const_cast<void *>(Addr), Len);
+#  endif
+
+#elif defined(__Fuchsia__)
+
+  zx_status_t Status = zx_cache_flush(Addr, Len, ZX_CACHE_FLUSH_INSN);
+  assert(Status == ZX_OK && "cannot invalidate instruction cache");
+
+#else
+
+#  if (defined(__POWERPC__) || defined (__ppc__) || \
+       defined(_POWER) || defined(_ARCH_PPC)) && defined(__GNUC__)
+  const size_t LineSize = 32;
+
+  const intptr_t Mask = ~(LineSize - 1);
+  const intptr_t StartLine = ((intptr_t) Addr) & Mask;
+  const intptr_t EndLine = ((intptr_t) Addr + Len + LineSize - 1) & Mask;
+
+  for (intptr_t Line = StartLine; Line < EndLine; Line += LineSize)
+    asm volatile("dcbf 0, %0" : : "r"(Line));
+  asm volatile("sync");
+
+  for (intptr_t Line = StartLine; Line < EndLine; Line += LineSize)
+    asm volatile("icbi 0, %0" : : "r"(Line));
+  asm volatile("isync");
+#  elif (defined(__arm__) || defined(__aarch64__) || defined(__mips__)) && \
+        defined(__GNUC__)
+  // FIXME: Can we safely always call this for __GNUC__ everywhere?
+  const char *Start = static_cast<const char *>(Addr);
+  const char *End = Start + Len;
+  __clear_cache(const_cast<char *>(Start), const_cast<char *>(End));
+#  endif
+
+#endif  // end apple
+
+  ValgrindDiscardTranslations(Addr, Len);
+}
+
+} // namespace sys
+} // namespace llvm