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//===-- SectionMemoryManager.cpp - The memory manager for MCJIT -----------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the implementation of the section-based memory manager
// used by MCJIT.
//
//===----------------------------------------------------------------------===//
#include "llvm/Config/config.h"
#include "llvm/Support/DynamicLibrary.h"
#include "SectionMemoryManager.h"
#ifdef __linux__
// These includes used by SectionMemoryManager::getPointerToNamedFunction()
// for Glibc trickery. Look 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 {
uint8_t *SectionMemoryManager::allocateDataSection(uintptr_t Size,
unsigned Alignment,
unsigned SectionID) {
if (!Alignment)
Alignment = 16;
uint8_t *Addr = (uint8_t*)calloc((Size + Alignment - 1)/Alignment, Alignment);
AllocatedDataMem.push_back(sys::MemoryBlock(Addr, Size));
return Addr;
}
uint8_t *SectionMemoryManager::allocateCodeSection(uintptr_t Size,
unsigned Alignment,
unsigned SectionID) {
if (!Alignment)
Alignment = 16;
unsigned NeedAllocate = Alignment * ((Size + Alignment - 1)/Alignment + 1);
uintptr_t Addr = 0;
// Look in the list of free code memory regions and use a block there if one
// is available.
for (int i = 0, e = FreeCodeMem.size(); i != e; ++i) {
sys::MemoryBlock &MB = FreeCodeMem[i];
if (MB.size() >= NeedAllocate) {
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.
FreeCodeMem[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.
sys::MemoryBlock MB = sys::Memory::AllocateRWX(NeedAllocate, 0, 0);
AllocatedCodeMem.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 AllocateRWX 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)
FreeCodeMem.push_back(sys::MemoryBlock((void*)(Addr + Size), FreeSize));
// Return aligned address
return (uint8_t*)Addr;
}
void SectionMemoryManager::invalidateInstructionCache() {
for (int i = 0, e = AllocatedCodeMem.size(); i != e; ++i)
sys::Memory::InvalidateInstructionCache(AllocatedCodeMem[i].base(),
AllocatedCodeMem[i].size());
}
void *SectionMemoryManager::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__
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;
}
SectionMemoryManager::~SectionMemoryManager() {
for (unsigned i = 0, e = AllocatedCodeMem.size(); i != e; ++i)
sys::Memory::ReleaseRWX(AllocatedCodeMem[i]);
for (unsigned i = 0, e = AllocatedDataMem.size(); i != e; ++i)
free(AllocatedDataMem[i].base());
}
} // namespace llvm
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