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//===-- 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/Config/config.h"
#include "llvm/ExecutionEngine/RTDyldMemoryManager.h"
#include "llvm/Support/DynamicLibrary.h"
#include "llvm/Support/ErrorHandling.h"
#include <cstdlib>
#ifdef __linux__
// These includes used by RTDyldMemoryManager::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(__ia64__) && \
!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*);
extern "C" void __deregister_frame(void*);
#else
// The building compiler does not have __(de)register_frame but
// it may be found at runtime in a dynamically-loaded library.
// For example, this happens when building LLVM with Visual C++
// but using the MingW runtime.
void __register_frame(void *p) {
static bool Searched = false;
static void *rf = 0;
if (!Searched) {
Searched = true;
rf = llvm::sys::DynamicLibrary::SearchForAddressOfSymbol(
"__register_frame");
}
if (rf)
((void (*)(void *))rf)(p);
}
void __deregister_frame(void *p) {
static bool Searched = false;
static void *df = 0;
if (!Searched) {
Searched = true;
df = llvm::sys::DynamicLibrary::SearchForAddressOfSymbol(
"__deregister_frame");
}
if (df)
((void (*)(void *))df)(p);
}
#endif
#ifdef __APPLE__
static const char *processFDE(const char *Entry, bool isDeregister) {
const char *P = Entry;
uint32_t Length = *((const uint32_t *)P);
P += 4;
uint32_t Offset = *((const uint32_t *)P);
if (Offset != 0) {
if (isDeregister)
__deregister_frame(const_cast<char *>(Entry));
else
__register_frame(const_cast<char *>(Entry));
}
return P + Length;
}
// This implementation handles frame registration for local targets.
// Memory managers for remote targets should re-implement this function
// and use the LoadAddr parameter.
void RTDyldMemoryManager::registerEHFrames(uint8_t *Addr,
uint64_t LoadAddr,
size_t Size) {
// On OS X OS X __register_frame takes a single FDE as an argument.
// See http://lists.cs.uiuc.edu/pipermail/llvmdev/2013-April/061768.html
const char *P = (const char *)Addr;
const char *End = P + Size;
do {
P = processFDE(P, false);
} while(P != End);
}
void RTDyldMemoryManager::deregisterEHFrames(uint8_t *Addr,
uint64_t LoadAddr,
size_t Size) {
const char *P = (const char *)Addr;
const char *End = P + Size;
do {
P = processFDE(P, true);
} while(P != End);
}
#else
void RTDyldMemoryManager::registerEHFrames(uint8_t *Addr,
uint64_t LoadAddr,
size_t Size) {
// On Linux __register_frame takes a single argument:
// a pointer to the start of the .eh_frame section.
// How can it find the end? Because crtendS.o is linked
// in and it has an .eh_frame section with four zero chars.
__register_frame(Addr);
}
void RTDyldMemoryManager::deregisterEHFrames(uint8_t *Addr,
uint64_t LoadAddr,
size_t Size) {
__deregister_frame(Addr);
}
#endif
static int jit_noop() {
return 0;
}
uint64_t RTDyldMemoryManager::getSymbolAddress(const std::string &Name) {
// This implementation assumes that the host program is the target.
// Clients generating code for a remote target should implement their own
// memory manager.
#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 (uint64_t)&stat;
if (Name == "fstat") return (uint64_t)&fstat;
if (Name == "lstat") return (uint64_t)&lstat;
if (Name == "stat64") return (uint64_t)&stat64;
if (Name == "fstat64") return (uint64_t)&fstat64;
if (Name == "lstat64") return (uint64_t)&lstat64;
if (Name == "atexit") return (uint64_t)&atexit;
if (Name == "mknod") return (uint64_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 (uint64_t)&jit_noop;
const char *NameStr = Name.c_str();
void *Ptr = sys::DynamicLibrary::SearchForAddressOfSymbol(NameStr);
if (Ptr)
return (uint64_t)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 (uint64_t)Ptr;
}
return 0;
}
void *RTDyldMemoryManager::getPointerToNamedFunction(const std::string &Name,
bool AbortOnFailure) {
uint64_t Addr = getSymbolAddress(Name);
if (!Addr && AbortOnFailure)
report_fatal_error("Program used external function '" + Name +
"' which could not be resolved!");
return (void*)Addr;
}
} // namespace llvm
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