Put RTDyldMemoryManager into its own file, and make it linked into

libExecutionEngine. Move method implementations that aren't specific to 
allocation out of SectionMemoryManager and into RTDyldMemoryManager.

This is in preparation for exposing RTDyldMemoryManager through the C 
API.

This is a fixed version of r182407. That revision broke builds because I 
forgot to move the conditional includes of various POSIX headers from 
SectionMemoryManager into RTDyldMemoryManager. Those includes are 
necessary because of how getPointerToNamedFunction works around the 
glibc libc_nonshared.a thing.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182411 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 115 insertions, 0 deletions

diff --git a/lib/ExecutionEngine/RTDyldMemoryManager.cpp b/lib/ExecutionEngine/RTDyldMemoryManager.cpp
new file mode 100644
index 0000000000..b7f5ae49d0
--- /dev/null
+++ b/lib/ExecutionEngine/RTDyldMemoryManager.cpp
@@ -0,0 +1,115 @@
+//===-- RTDyldMemoryManager.cpp - Memory manager for MC-JIT -----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Implementation of the runtime dynamic memory manager base class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ExecutionEngine/RTDyldMemoryManager.h"
+#include "llvm/Support/DynamicLibrary.h"
+#include "llvm/Support/ErrorHandling.h"
+
+#ifdef __linux__
+  // These includes used by SectionMemoryManager::getPointerToNamedFunction()
+  // for Glibc trickery. See comments in this function for more information.
+  #ifdef HAVE_SYS_STAT_H
+    #include <sys/stat.h>
+  #endif
+  #include <fcntl.h>
+  #include <unistd.h>
+#endif
+
+namespace llvm {
+
+RTDyldMemoryManager::~RTDyldMemoryManager() {}
+
+// Determine whether we can register EH tables.
+#if (defined(__GNUC__) && !defined(__ARM_EABI__) && \
+     !defined(__USING_SJLJ_EXCEPTIONS__))
+#define HAVE_EHTABLE_SUPPORT 1
+#else
+#define HAVE_EHTABLE_SUPPORT 0
+#endif
+
+#if HAVE_EHTABLE_SUPPORT
+extern "C" void __register_frame(void*);
+
+static const char *processFDE(const char *Entry) {
+  const char *P = Entry;
+  uint32_t Length = *((uint32_t*)P);
+  P += 4;
+  uint32_t Offset = *((uint32_t*)P);
+  if (Offset != 0)
+    __register_frame((void*)Entry);
+  return P + Length;
+}
+#endif
+
+void RTDyldMemoryManager::registerEHFrames(StringRef SectionData) {
+#if HAVE_EHTABLE_SUPPORT
+  const char *P = SectionData.data();
+  const char *End = SectionData.data() + SectionData.size();
+  do  {
+    P = processFDE(P);
+  } while(P != End);
+#endif
+}
+
+static int jit_noop() {
+  return 0;
+}
+
+void *RTDyldMemoryManager::getPointerToNamedFunction(const std::string &Name,
+                                                     bool AbortOnFailure) {
+#if defined(__linux__)
+  //===--------------------------------------------------------------------===//
+  // Function stubs that are invoked instead of certain library calls
+  //
+  // Force the following functions to be linked in to anything that uses the
+  // JIT. This is a hack designed to work around the all-too-clever Glibc
+  // strategy of making these functions work differently when inlined vs. when
+  // not inlined, and hiding their real definitions in a separate archive file
+  // that the dynamic linker can't see. For more info, search for
+  // 'libc_nonshared.a' on Google, or read http://llvm.org/PR274.
+  if (Name == "stat") return (void*)(intptr_t)&stat;
+  if (Name == "fstat") return (void*)(intptr_t)&fstat;
+  if (Name == "lstat") return (void*)(intptr_t)&lstat;
+  if (Name == "stat64") return (void*)(intptr_t)&stat64;
+  if (Name == "fstat64") return (void*)(intptr_t)&fstat64;
+  if (Name == "lstat64") return (void*)(intptr_t)&lstat64;
+  if (Name == "atexit") return (void*)(intptr_t)&atexit;
+  if (Name == "mknod") return (void*)(intptr_t)&mknod;
+#endif // __linux__
+
+  // We should not invoke parent's ctors/dtors from generated main()!
+  // On Mingw and Cygwin, the symbol __main is resolved to
+  // callee's(eg. tools/lli) one, to invoke wrong duplicated ctors
+  // (and register wrong callee's dtors with atexit(3)).
+  // We expect ExecutionEngine::runStaticConstructorsDestructors()
+  // is called before ExecutionEngine::runFunctionAsMain() is called.
+  if (Name == "__main") return (void*)(intptr_t)&jit_noop;
+
+  const char *NameStr = Name.c_str();
+  void *Ptr = sys::DynamicLibrary::SearchForAddressOfSymbol(NameStr);
+  if (Ptr) return Ptr;
+
+  // If it wasn't found and if it starts with an underscore ('_') character,
+  // try again without the underscore.
+  if (NameStr[0] == '_') {
+    Ptr = sys::DynamicLibrary::SearchForAddressOfSymbol(NameStr+1);
+    if (Ptr) return Ptr;
+  }
+
+  if (AbortOnFailure)
+    report_fatal_error("Program used external function '" + Name +
+                       "' which could not be resolved!");
+  return 0;
+}
+
+} // namespace llvm