https://github.com/JuliaLang/julia
Tip revision: 7711781875620866da6a4f7dc545b355e5b1f24c authored by Alex Arslan on 10 July 2018, 00:08:41 UTC
Set VERSION to 0.6.5-pre (#28013)
Set VERSION to 0.6.5-pre (#28013)
Tip revision: 7711781
jitlayers.cpp
// This file is a part of Julia. License is MIT: https://julialang.org/license
#include "llvm-version.h"
#include "platform.h"
#include "options.h"
#include <iostream>
#include <sstream>
// analysis passes
#include <llvm/Analysis/Passes.h>
#if JL_LLVM_VERSION >= 30800
#include <llvm/Analysis/BasicAliasAnalysis.h>
#include <llvm/Analysis/TypeBasedAliasAnalysis.h>
#endif
#if JL_LLVM_VERSION >= 30700
#include <llvm/Analysis/TargetTransformInfo.h>
#include <llvm/Analysis/TargetLibraryInfo.h>
#endif
#if JL_LLVM_VERSION >= 30500
#include <llvm/IR/Verifier.h>
#else
#include <llvm/Analysis/Verifier.h>
#endif
#if defined(USE_POLLY)
#include <polly/RegisterPasses.h>
#include <polly/LinkAllPasses.h>
#include <polly/CodeGen/CodegenCleanup.h>
#endif
#include <llvm/Transforms/IPO.h>
#include <llvm/Transforms/Scalar.h>
#include <llvm/Transforms/Utils/BasicBlockUtils.h>
#include <llvm/Transforms/Instrumentation.h>
#include <llvm/Transforms/Vectorize.h>
#if JL_LLVM_VERSION >= 30900
#include <llvm/Transforms/Scalar/GVN.h>
#endif
#if JL_LLVM_VERSION >= 40000
#include <llvm/Transforms/IPO/AlwaysInliner.h>
#endif
namespace llvm {
extern Pass *createLowerSimdLoopPass();
}
#if JL_LLVM_VERSION >= 40000
# include <llvm/Bitcode/BitcodeWriter.h>
#else
# include <llvm/Bitcode/ReaderWriter.h>
#endif
#if JL_LLVM_VERSION >= 30500
#include <llvm/Bitcode/BitcodeWriterPass.h>
#endif
#include <llvm/Transforms/Utils/Cloning.h>
#include <llvm/ExecutionEngine/JITEventListener.h>
// target support
#include <llvm/ADT/Triple.h>
#include <llvm/Support/TargetRegistry.h>
#if JL_LLVM_VERSION < 30700
#include <llvm/Target/TargetLibraryInfo.h>
#endif
#include <llvm/IR/DataLayout.h>
#include <llvm/Support/DynamicLibrary.h>
#include <llvm/Support/raw_ostream.h>
#include <llvm/Support/FormattedStream.h>
#include <llvm/ADT/StringMap.h>
#include <llvm/ADT/StringSet.h>
#include <llvm/ADT/SmallSet.h>
#include "fix_llvm_assert.h"
using namespace llvm;
#include "julia.h"
#include "julia_internal.h"
#include "jitlayers.h"
#ifdef USE_MCJIT
RTDyldMemoryManager* createRTDyldMemoryManager(void);
#endif
static Type *T_void;
static IntegerType *T_uint32;
static IntegerType *T_uint64;
static IntegerType *T_size;
static Type *T_psize;
static Type *T_pvoidfunc;
static Type *T_pjlvalue;
void jl_init_jit(Type *T_pjlvalue_)
{
T_void = Type::getVoidTy(jl_LLVMContext);
T_uint32 = Type::getInt32Ty(jl_LLVMContext);
T_uint64 = Type::getInt64Ty(jl_LLVMContext);
if (sizeof(size_t) == 8)
T_size = T_uint64;
else
T_size = T_uint32;
T_psize = PointerType::get(T_size, 0);
T_pvoidfunc = FunctionType::get(T_void, /*isVarArg*/false)->getPointerTo();
T_pjlvalue = T_pjlvalue_;
}
// Except for parts of this file which were copied from LLVM, under the UIUC license (marked below).
// this defines the set of optimization passes defined for Julia at various optimization levels
#if JL_LLVM_VERSION >= 30700
void addOptimizationPasses(legacy::PassManager *PM)
#else
void addOptimizationPasses(PassManager *PM)
#endif
{
PM->add(createLowerGCFramePass());
#ifdef JL_DEBUG_BUILD
PM->add(createVerifierPass());
#endif
#if defined(JL_ASAN_ENABLED)
# if JL_LLVM_VERSION >= 30700 && JL_LLVM_VERSION < 30800
// LLVM 3.7 BUG: ASAN pass doesn't properly initialize its dependencies
initializeTargetLibraryInfoWrapperPassPass(*PassRegistry::getPassRegistry());
# endif
PM->add(createAddressSanitizerFunctionPass());
#endif
#if defined(JL_MSAN_ENABLED)
PM->add(llvm::createMemorySanitizerPass(true));
#endif
if (jl_options.opt_level == 0) {
PM->add(createCFGSimplificationPass()); // Clean up disgusting code
PM->add(createMemCpyOptPass()); // Remove memcpy / form memset
PM->add(createLowerPTLSPass(imaging_mode));
#if JL_LLVM_VERSION >= 40000
PM->add(createAlwaysInlinerLegacyPass()); // Respect always_inline
#else
PM->add(createAlwaysInlinerPass()); // Respect always_inline
#endif
return;
}
#if JL_LLVM_VERSION >= 30700
PM->add(createTargetTransformInfoWrapperPass(jl_TargetMachine->getTargetIRAnalysis()));
#else
jl_TargetMachine->addAnalysisPasses(*PM);
#endif
#if JL_LLVM_VERSION >= 30800
PM->add(createTypeBasedAAWrapperPass());
#else
PM->add(createTypeBasedAliasAnalysisPass());
#endif
if (jl_options.opt_level >= 3) {
#if JL_LLVM_VERSION >= 30800
PM->add(createBasicAAWrapperPass());
#else
PM->add(createBasicAliasAnalysisPass());
#endif
}
// list of passes from vmkit
PM->add(createCFGSimplificationPass()); // Clean up disgusting code
PM->add(createPromoteMemoryToRegisterPass()); // Kill useless allocas
// hopefully these functions (from llvmcall) don't try to interact with the Julia runtime
// or have anything that might corrupt the createLowerPTLSPass pass
#if JL_LLVM_VERSION >= 40000
PM->add(createAlwaysInlinerLegacyPass()); // Respect always_inline
#else
PM->add(createAlwaysInlinerPass()); // Respect always_inline
#endif
#ifndef INSTCOMBINE_BUG
PM->add(createInstructionCombiningPass()); // Cleanup for scalarrepl.
#endif
// Let the InstCombine pass remove the unnecessary load of
// safepoint address first
PM->add(createLowerPTLSPass(imaging_mode));
PM->add(createSROAPass()); // Break up aggregate allocas
#ifndef INSTCOMBINE_BUG
PM->add(createInstructionCombiningPass()); // Cleanup for scalarrepl.
#endif
PM->add(createJumpThreadingPass()); // Thread jumps.
// NOTE: CFG simp passes after this point seem to hurt native codegen.
// See issue #6112. Should be re-evaluated when we switch to MCJIT.
//PM->add(createCFGSimplificationPass()); // Merge & remove BBs
#ifndef INSTCOMBINE_BUG
PM->add(createInstructionCombiningPass()); // Combine silly seq's
#endif
//PM->add(createCFGSimplificationPass()); // Merge & remove BBs
PM->add(createReassociatePass()); // Reassociate expressions
// this has the potential to make some things a bit slower
//PM->add(createBBVectorizePass());
PM->add(createEarlyCSEPass()); //// ****
PM->add(createLoopIdiomPass()); //// ****
PM->add(createLoopRotatePass()); // Rotate loops.
#ifdef USE_POLLY
// LCSSA (which has already run at this point due to the dependencies of the
// above passes) introduces redundant phis that hinder Polly. Therefore we
// run InstCombine here to remove them.
PM->add(createInstructionCombiningPass());
PM->add(polly::createCodePreparationPass());
polly::registerPollyPasses(*PM);
PM->add(polly::createCodegenCleanupPass());
#endif
// LoopRotate strips metadata from terminator, so run LowerSIMD afterwards
PM->add(createLowerSimdLoopPass()); // Annotate loop marked with "simdloop" as LLVM parallel loop
PM->add(createLICMPass()); // Hoist loop invariants
PM->add(createLoopUnswitchPass()); // Unswitch loops.
// Subsequent passes not stripping metadata from terminator
#ifndef INSTCOMBINE_BUG
PM->add(createInstructionCombiningPass());
#endif
PM->add(createIndVarSimplifyPass()); // Canonicalize indvars
PM->add(createLoopDeletionPass()); // Delete dead loops
#if JL_LLVM_VERSION >= 30500
PM->add(createSimpleLoopUnrollPass()); // Unroll small loops
#else
PM->add(createLoopUnrollPass()); // Unroll small loops
#endif
#if JL_LLVM_VERSION < 30500 && !defined(INSTCOMBINE_BUG)
PM->add(createLoopVectorizePass()); // Vectorize loops
#endif
//PM->add(createLoopStrengthReducePass()); // (jwb added)
#ifndef INSTCOMBINE_BUG
PM->add(createInstructionCombiningPass()); // Clean up after the unroller
#endif
PM->add(createGVNPass()); // Remove redundancies
PM->add(createMemCpyOptPass()); // Remove memcpy / form memset
PM->add(createSCCPPass()); // Constant prop with SCCP
// Run instcombine after redundancy elimination to exploit opportunities
// opened up by them.
PM->add(createSinkingPass()); ////////////// ****
PM->add(createInstructionSimplifierPass());///////// ****
#ifndef INSTCOMBINE_BUG
PM->add(createInstructionCombiningPass());
#endif
PM->add(createJumpThreadingPass()); // Thread jumps
PM->add(createDeadStoreEliminationPass()); // Delete dead stores
// see if all of the constant folding has exposed more loops
// to simplification and deletion
// this helps significantly with cleaning up iteration
PM->add(createCFGSimplificationPass()); // Merge & remove BBs
PM->add(createLoopIdiomPass());
PM->add(createLoopDeletionPass()); // Delete dead loops
PM->add(createJumpThreadingPass()); // Thread jumps
#if JL_LLVM_VERSION >= 30500
if (jl_options.opt_level >= 3) {
PM->add(createSLPVectorizerPass()); // Vectorize straight-line code
}
#endif
PM->add(createAggressiveDCEPass()); // Delete dead instructions
#if JL_LLVM_VERSION >= 30500
if (jl_options.opt_level >= 3)
PM->add(createInstructionCombiningPass()); // Clean up after SLP loop vectorizer
PM->add(createLoopVectorizePass()); // Vectorize loops
PM->add(createInstructionCombiningPass()); // Clean up after loop vectorizer
#endif
}
#ifdef USE_ORCJIT
#if JL_LLVM_VERSION < 30800
void notifyObjectLoaded(RTDyldMemoryManager *memmgr,
llvm::orc::ObjectLinkingLayerBase::ObjSetHandleT H);
#endif
// ------------------------ TEMPORARILY COPIED FROM LLVM -----------------
// This must be kept in sync with gdb/gdb/jit.h .
extern "C" {
typedef enum {
JIT_NOACTION = 0,
JIT_REGISTER_FN,
JIT_UNREGISTER_FN
} jit_actions_t;
struct jit_code_entry {
struct jit_code_entry *next_entry;
struct jit_code_entry *prev_entry;
const char *symfile_addr;
uint64_t symfile_size;
};
struct jit_descriptor {
uint32_t version;
// This should be jit_actions_t, but we want to be specific about the
// bit-width.
uint32_t action_flag;
struct jit_code_entry *relevant_entry;
struct jit_code_entry *first_entry;
};
// We put information about the JITed function in this global, which the
// debugger reads. Make sure to specify the version statically, because the
// debugger checks the version before we can set it during runtime.
extern struct jit_descriptor __jit_debug_descriptor;
LLVM_ATTRIBUTE_NOINLINE extern void __jit_debug_register_code();
}
namespace {
// Use a local variable to hold the addresses to avoid generating a PLT
// on the function call.
// It messes up the GDB lookup logic with dynamically linked LLVM.
// (Ref https://sourceware.org/bugzilla/show_bug.cgi?id=20633)
// Use `volatile` to make sure the call always loads this slot.
void (*volatile jit_debug_register_code)() = __jit_debug_register_code;
using namespace llvm;
using namespace llvm::object;
using namespace llvm::orc;
/// Do the registration.
void NotifyDebugger(jit_code_entry *JITCodeEntry)
{
__jit_debug_descriptor.action_flag = JIT_REGISTER_FN;
// Insert this entry at the head of the list.
JITCodeEntry->prev_entry = nullptr;
jit_code_entry *NextEntry = __jit_debug_descriptor.first_entry;
JITCodeEntry->next_entry = NextEntry;
if (NextEntry) {
NextEntry->prev_entry = JITCodeEntry;
}
__jit_debug_descriptor.first_entry = JITCodeEntry;
__jit_debug_descriptor.relevant_entry = JITCodeEntry;
jit_debug_register_code();
}
}
// ------------------------ END OF TEMPORARY COPY FROM LLVM -----------------
#if defined(_OS_LINUX_)
// Resolve non-lock free atomic functions in the libatomic library.
// This is the library that provides support for c11/c++11 atomic operations.
static uint64_t resolve_atomic(const char *name)
{
static void *atomic_hdl = jl_load_dynamic_library_e("libatomic",
JL_RTLD_LOCAL);
static const char *const atomic_prefix = "__atomic_";
if (!atomic_hdl)
return 0;
if (strncmp(name, atomic_prefix, strlen(atomic_prefix)) != 0)
return 0;
return (uintptr_t)jl_dlsym_e(atomic_hdl, name);
}
#endif
// Custom object emission notification handler for the JuliaOJIT
extern JITEventListener *CreateJuliaJITEventListener();
JuliaOJIT::DebugObjectRegistrar::DebugObjectRegistrar(JuliaOJIT &JIT)
: JuliaListener(CreateJuliaJITEventListener()),
JIT(JIT) {}
JL_DLLEXPORT void ORCNotifyObjectEmitted(JITEventListener *Listener,
const object::ObjectFile &obj,
const object::ObjectFile &debugObj,
const RuntimeDyld::LoadedObjectInfo &L,
RTDyldMemoryManager *memmgr);
// TODO: hook up RegisterJITEventListener, instead of hard-coding the GDB and JuliaListener targets
template <typename ObjSetT, typename LoadResult>
void JuliaOJIT::DebugObjectRegistrar::operator()(RTDyldObjectLinkingLayerBase::ObjSetHandleT H,
const ObjSetT &Objects, const LoadResult &LOS)
{
#if JL_LLVM_VERSION < 30800
notifyObjectLoaded(JIT.MemMgr, H);
#endif
auto oit = Objects.begin();
auto lit = LOS.begin();
for (; oit != Objects.end(); ++oit, ++lit) {
#if JL_LLVM_VERSION >= 30900
const auto &Object = (*oit)->getBinary();
#else
auto &Object = *oit;
#endif
auto &LO = *lit;
OwningBinary<object::ObjectFile> SavedObject = LO->getObjectForDebug(*Object);
// If the debug object is unavailable, save (a copy of) the original object
// for our backtraces
if (!SavedObject.getBinary()) {
// This is unfortunate, but there doesn't seem to be a way to take
// ownership of the original buffer
auto NewBuffer = MemoryBuffer::getMemBufferCopy(Object->getData(),
Object->getFileName());
auto NewObj = ObjectFile::createObjectFile(NewBuffer->getMemBufferRef());
assert(NewObj);
SavedObject = OwningBinary<object::ObjectFile>(std::move(*NewObj),
std::move(NewBuffer));
}
else {
NotifyGDB(SavedObject);
}
SavedObjects.push_back(std::move(SavedObject));
ORCNotifyObjectEmitted(JuliaListener.get(),
*Object,
*SavedObjects.back().getBinary(),
*LO, JIT.MemMgr);
// record all of the exported symbols defined in this object
// in the primary hash table for the enclosing JIT
for (auto &Symbol : Object->symbols()) {
auto Flags = Symbol.getFlags();
if (Flags & object::BasicSymbolRef::SF_Undefined)
continue;
if (!(Flags & object::BasicSymbolRef::SF_Exported))
continue;
auto NameOrError = Symbol.getName();
assert(NameOrError);
auto Name = NameOrError.get();
auto Sym = JIT.CompileLayer.findSymbolIn(H, Name, true);
assert(Sym);
// note: calling getAddress here eagerly finalizes H
// as an alternative, we could store the JITSymbol instead
// (which would present a lazy-initializer functor interface instead)
JIT.LocalSymbolTable[Name] = (void*)(uintptr_t)Sym.getAddress();
}
}
}
void JuliaOJIT::DebugObjectRegistrar::NotifyGDB(OwningBinary<object::ObjectFile> &DebugObj)
{
const char *Buffer = DebugObj.getBinary()->getMemoryBufferRef().getBufferStart();
size_t Size = DebugObj.getBinary()->getMemoryBufferRef().getBufferSize();
assert(Buffer && "Attempt to register a null object with a debugger.");
jit_code_entry *JITCodeEntry = new jit_code_entry();
if (!JITCodeEntry) {
jl_printf(JL_STDERR, "WARNING: Allocation failed when registering a JIT entry!\n");
}
else {
JITCodeEntry->symfile_addr = Buffer;
JITCodeEntry->symfile_size = Size;
NotifyDebugger(JITCodeEntry);
}
}
JuliaOJIT::JuliaOJIT(TargetMachine &TM)
: TM(TM),
DL(TM.createDataLayout()),
ObjStream(ObjBufferSV),
MemMgr(createRTDyldMemoryManager()),
ObjectLayer(DebugObjectRegistrar(*this)),
CompileLayer(
ObjectLayer,
[this](Module &M) {
JL_TIMING(LLVM_OPT);
PM.run(M);
std::unique_ptr<MemoryBuffer> ObjBuffer(
new ObjectMemoryBuffer(std::move(ObjBufferSV)));
auto Obj = object::ObjectFile::createObjectFile(ObjBuffer->getMemBufferRef());
if (!Obj) {
#if JL_LLVM_VERSION >= 50000
M.print(llvm::dbgs(), nullptr, false, true);
#else
M.dump();
#endif
#if JL_LLVM_VERSION >= 30900
std::string Buf;
raw_string_ostream OS(Buf);
logAllUnhandledErrors(Obj.takeError(), OS, "");
OS.flush();
llvm::report_fatal_error("FATAL: Unable to compile LLVM Module: '" + Buf + "'\n"
"The module's content was printed above. Please file a bug report");
#else
llvm::report_fatal_error("FATAL: Unable to compile LLVM Module.\n"
"The module's content was printed above. Please file a bug report");
#endif
}
return OwningObj(std::move(*Obj), std::move(ObjBuffer));
}
)
{
if (!jl_generating_output()) {
addOptimizationPasses(&PM);
}
else {
PM.add(createLowerGCFramePass());
PM.add(createLowerPTLSPass(imaging_mode));
}
if (TM.addPassesToEmitMC(PM, Ctx, ObjStream))
llvm_unreachable("Target does not support MC emission.");
// Make sure SectionMemoryManager::getSymbolAddressInProcess can resolve
// symbols in the program as well. The nullptr argument to the function
// tells DynamicLibrary to load the program, not a library.
std::string *ErrorStr = nullptr;
if (sys::DynamicLibrary::LoadLibraryPermanently(nullptr, ErrorStr))
report_fatal_error("FATAL: unable to dlopen self\n" + *ErrorStr);
}
void JuliaOJIT::addGlobalMapping(StringRef Name, uint64_t Addr)
{
bool successful = GlobalSymbolTable.insert(std::make_pair(Name, (void*)Addr)).second;
(void)successful;
assert(successful);
}
void JuliaOJIT::addGlobalMapping(const GlobalValue *GV, void *Addr)
{
addGlobalMapping(getMangledName(GV), (uintptr_t)Addr);
}
void *JuliaOJIT::getPointerToGlobalIfAvailable(StringRef S)
{
SymbolTableT::const_iterator pos = GlobalSymbolTable.find(S);
if (pos != GlobalSymbolTable.end())
return pos->second;
return nullptr;
}
void *JuliaOJIT::getPointerToGlobalIfAvailable(const GlobalValue *GV)
{
return getPointerToGlobalIfAvailable(getMangledName(GV));
}
void JuliaOJIT::addModule(std::unique_ptr<Module> M)
{
#ifndef JL_NDEBUG
// validate the relocations for M
for (Module::iterator I = M->begin(), E = M->end(); I != E; ) {
Function *F = &*I;
++I;
if (F->isDeclaration()) {
if (F->use_empty())
F->eraseFromParent();
else if (!(isIntrinsicFunction(F) ||
findUnmangledSymbol(F->getName()) ||
SectionMemoryManager::getSymbolAddressInProcess(
getMangledName(F->getName())))) {
std::cerr << "FATAL ERROR: "
<< "Symbol \"" << F->getName().str() << "\""
<< "not found";
abort();
}
}
}
#endif
JL_TIMING(LLVM_MODULE_FINISH);
// We need a memory manager to allocate memory and resolve symbols for this
// new module. Create one that resolves symbols by looking back into the JIT.
auto Resolver = orc::createLambdaResolver(
[&](const std::string &Name) {
// TODO: consider moving the FunctionMover resolver here
// Step 0: ObjectLinkingLayer has checked whether it is in the current module
// Step 1: See if it's something known to the ExecutionEngine
if (auto Sym = findSymbol(Name, true)) {
#if JL_LLVM_VERSION >= 40000
// `findSymbol` already eagerly resolved the address
// return it directly.
return Sym;
#else
return RuntimeDyld::SymbolInfo(Sym.getAddress(),
Sym.getFlags());
#endif
}
// Step 2: Search the program symbols
if (uint64_t addr = SectionMemoryManager::getSymbolAddressInProcess(Name))
return JL_SymbolInfo(addr, JITSymbolFlags::Exported);
#if defined(_OS_LINUX_)
if (uint64_t addr = resolve_atomic(Name.c_str()))
return JL_SymbolInfo(addr, JITSymbolFlags::Exported);
#endif
// Return failure code
return JL_SymbolInfo(nullptr);
},
[](const std::string &S) { return nullptr; }
);
SmallVector<std::unique_ptr<Module>,1> Ms;
Ms.push_back(std::move(M));
auto modset = CompileLayer.addModuleSet(std::move(Ms), MemMgr,
std::move(Resolver));
// Force LLVM to emit the module so that we can register the symbols
// in our lookup table.
CompileLayer.emitAndFinalize(modset);
}
void JuliaOJIT::removeModule(ModuleHandleT H)
{
CompileLayer.removeModuleSet(H);
}
JL_JITSymbol JuliaOJIT::findSymbol(const std::string &Name, bool ExportedSymbolsOnly)
{
void *Addr = nullptr;
if (ExportedSymbolsOnly) {
// Step 1: Check against list of known external globals
Addr = getPointerToGlobalIfAvailable(Name);
}
// Step 2: Search all previously emitted symbols
if (Addr == nullptr)
Addr = LocalSymbolTable[Name];
return JL_JITSymbol((uintptr_t)Addr, JITSymbolFlags::Exported);
}
JL_JITSymbol JuliaOJIT::findUnmangledSymbol(const std::string Name)
{
return findSymbol(getMangledName(Name), true);
}
uint64_t JuliaOJIT::getGlobalValueAddress(const std::string &Name)
{
return findSymbol(getMangledName(Name), false).getAddress();
}
uint64_t JuliaOJIT::getFunctionAddress(const std::string &Name)
{
return findSymbol(getMangledName(Name), false).getAddress();
}
Function *JuliaOJIT::FindFunctionNamed(const std::string &Name)
{
return shadow_output->getFunction(Name);
}
void JuliaOJIT::RegisterJITEventListener(JITEventListener *L)
{
// TODO
}
const DataLayout& JuliaOJIT::getDataLayout() const
{
return DL;
}
const Triple& JuliaOJIT::getTargetTriple() const
{
return TM.getTargetTriple();
}
std::string JuliaOJIT::getMangledName(const std::string &Name)
{
SmallString<128> FullName;
Mangler::getNameWithPrefix(FullName, Name, DL);
return FullName.str();
}
std::string JuliaOJIT::getMangledName(const GlobalValue *GV)
{
return getMangledName(GV->getName());
}
JuliaOJIT *jl_ExecutionEngine;
#else
ExecutionEngine *jl_ExecutionEngine;
#endif
// MSVC's link.exe requires each function declaration to have a Comdat section
// So rather than litter the code with conditionals,
// all global values that get emitted call this function
// and it decides whether the definition needs a Comdat section and adds the appropriate declaration
// TODO: consider moving this into jl_add_to_shadow or jl_dump_shadow? the JIT doesn't care, so most calls are now no-ops
template<class T> // for GlobalObject's
static T *addComdat(T *G)
{
#if defined(_OS_WINDOWS_) && JL_LLVM_VERSION >= 30500
if (imaging_mode && !G->isDeclaration()) {
// Add comdat information to make MSVC link.exe happy
// it's valid to emit this for ld.exe too,
// but makes it very slow to link for no benefit
if (G->getParent() == shadow_output) {
#if defined(_COMPILER_MICROSOFT_)
Comdat *jl_Comdat = G->getParent()->getOrInsertComdat(G->getName());
// ELF only supports Comdat::Any
jl_Comdat->setSelectionKind(Comdat::NoDuplicates);
G->setComdat(jl_Comdat);
#endif
#if defined(_CPU_X86_64_)
// Add unwind exception personalities to functions to handle async exceptions
assert(!juliapersonality_func || juliapersonality_func->getParent() == shadow_output);
if (Function *F = dyn_cast<Function>(G))
F->setPersonalityFn(juliapersonality_func);
#endif
}
// add __declspec(dllexport) to everything marked for export
if (G->getLinkage() == GlobalValue::ExternalLinkage)
G->setDLLStorageClass(GlobalValue::DLLExportStorageClass);
else
G->setDLLStorageClass(GlobalValue::DefaultStorageClass);
}
#endif
return G;
}
// destructively move the contents of src into dest
// this assumes that the targets of the two modules are the same
// including the DataLayout and ModuleFlags (for example)
// and that there is no module-level assembly
static void jl_merge_module(Module *dest, std::unique_ptr<Module> src)
{
assert(dest != src.get());
for (Module::global_iterator I = src->global_begin(), E = src->global_end(); I != E;) {
GlobalVariable *sG = &*I;
GlobalValue *dG = dest->getNamedValue(sG->getName());
++I;
// Replace a declaration with the definition:
if (dG) {
if (sG->isDeclaration()) {
sG->replaceAllUsesWith(dG);
sG->eraseFromParent();
continue;
}
else {
dG->replaceAllUsesWith(sG);
dG->eraseFromParent();
}
}
// Reparent the global variable:
sG->removeFromParent();
dest->getGlobalList().push_back(sG);
// Comdat is owned by the Module, recreate it in the new parent:
addComdat(sG);
}
for (Module::iterator I = src->begin(), E = src->end(); I != E;) {
Function *sG = &*I;
GlobalValue *dG = dest->getNamedValue(sG->getName());
++I;
// Replace a declaration with the definition:
if (dG) {
if (sG->isDeclaration()) {
sG->replaceAllUsesWith(dG);
sG->eraseFromParent();
continue;
}
else {
dG->replaceAllUsesWith(sG);
dG->eraseFromParent();
}
}
// Reparent the global variable:
sG->removeFromParent();
dest->getFunctionList().push_back(sG);
// Comdat is owned by the Module, recreate it in the new parent:
addComdat(sG);
}
for (Module::alias_iterator I = src->alias_begin(), E = src->alias_end(); I != E;) {
GlobalAlias *sG = &*I;
GlobalValue *dG = dest->getNamedValue(sG->getName());
++I;
if (dG) {
if (!dG->isDeclaration()) { // aliases are always definitions, so this test is reversed from the above two
sG->replaceAllUsesWith(dG);
sG->eraseFromParent();
continue;
}
else {
dG->replaceAllUsesWith(sG);
dG->eraseFromParent();
}
}
sG->removeFromParent();
dest->getAliasList().push_back(sG);
}
// metadata nodes need to be explicitly merged not just copied
// so there are special passes here for each known type of metadata
NamedMDNode *sNMD = src->getNamedMetadata("llvm.dbg.cu");
if (sNMD) {
NamedMDNode *dNMD = dest->getOrInsertNamedMetadata("llvm.dbg.cu");
#if JL_LLVM_VERSION >= 30500
for (NamedMDNode::op_iterator I = sNMD->op_begin(), E = sNMD->op_end(); I != E; ++I) {
dNMD->addOperand(*I);
}
#else
for (unsigned i = 0, l = sNMD->getNumOperands(); i < l; i++) {
dNMD->addOperand(sNMD->getOperand(i));
}
#endif
}
}
// to finalize a function, look up its name in the `module_for_fname` map of
// unfinalized functions and merge it, plus any other modules it depends upon,
// into `collector` then add `collector` to the execution engine
static StringMap<Module*> module_for_fname;
static void jl_merge_recursive(Module *m, Module *collector);
#if defined(USE_MCJIT) || defined(USE_ORCJIT)
static void jl_add_to_ee(std::unique_ptr<Module> m)
{
#if defined(_CPU_X86_64_) && defined(_OS_WINDOWS_) && JL_LLVM_VERSION >= 30500
// Add special values used by debuginfo to build the UnwindData table registration for Win64
ArrayType *atype = ArrayType::get(T_uint32, 3); // want 4-byte alignment of 12-bytes of data
(new GlobalVariable(*m, atype,
false, GlobalVariable::InternalLinkage,
ConstantAggregateZero::get(atype), "__UnwindData"))->setSection(".text");
(new GlobalVariable(*m, atype,
false, GlobalVariable::InternalLinkage,
ConstantAggregateZero::get(atype), "__catchjmp"))->setSection(".text");
#endif
assert(jl_ExecutionEngine);
#if JL_LLVM_VERSION >= 30600
jl_ExecutionEngine->addModule(std::move(m));
#else
jl_ExecutionEngine->addModule(m.release());
#endif
}
void jl_finalize_function(Function *F)
{
std::unique_ptr<Module> m(module_for_fname.lookup(F->getName()));
if (m) {
jl_merge_recursive(m.get(), m.get());
jl_add_to_ee(std::move(m));
}
}
#else
static bool jl_try_finalize(Module *m)
{
for (Module::iterator I = m->begin(), E = m->end(); I != E; ++I) {
Function *F = &*I;
if (F->isDeclaration() && !isIntrinsicFunction(F)) {
if (!jl_can_finalize_function(F))
return false;
}
}
jl_merge_recursive(m, shadow_output);
jl_merge_module(shadow_output, std::unique_ptr<Module>(m));
return true;
}
#endif
static void jl_finalize_function(const std::string &F, Module *collector)
{
std::unique_ptr<Module> m(module_for_fname.lookup(F));
if (m) {
jl_merge_recursive(m.get(), collector);
jl_merge_module(collector, std::move(m));
}
}
static void jl_merge_recursive(Module *m, Module *collector)
{
// probably not many unresolved declarations, but be sure to iterate over their Names,
// since the declarations may get destroyed by the jl_merge_module call.
// this is also why we copy the Name string, rather than save a StringRef
SmallVector<std::string, 8> to_finalize;
for (Module::iterator I = m->begin(), E = m->end(); I != E; ++I) {
Function *F = &*I;
if (!F->isDeclaration()) {
module_for_fname.erase(F->getName());
}
else if (!isIntrinsicFunction(F)) {
to_finalize.push_back(F->getName().str());
}
}
for (const auto F : to_finalize) {
jl_finalize_function(F, collector);
}
}
// see if any of the functions needed by F are still WIP
static StringSet<> incomplete_fname;
static bool jl_can_finalize_function(StringRef F, SmallSet<Module*, 16> &known)
{
if (incomplete_fname.find(F) != incomplete_fname.end())
return false;
Module *M = module_for_fname.lookup(F);
#if JL_LLVM_VERSION >= 30500
if (M && known.insert(M).second)
#else
if (M && known.insert(M))
#endif
{
for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I) {
Function *F = &*I;
if (F->isDeclaration() && !isIntrinsicFunction(F)) {
if (!jl_can_finalize_function(F->getName(), known))
return false;
}
}
}
return true;
}
bool jl_can_finalize_function(Function *F)
{
SmallSet<Module*, 16> known;
return jl_can_finalize_function(F->getName(), known);
}
// let the JIT know this function is a WIP
void jl_init_function(Function *F)
{
incomplete_fname.insert(F->getName());
}
// this takes ownership of a module after code emission is complete
// and will add it to the execution engine when required (by jl_finalize_function)
void jl_finalize_module(Module *m, bool shadow)
{
#if !defined(USE_ORCJIT)
jl_globalPM->run(*m);
#endif
// record the function names that are part of this Module
// so it can be added to the JIT when needed
for (Module::iterator I = m->begin(), E = m->end(); I != E; ++I) {
Function *F = &*I;
if (!F->isDeclaration()) {
bool known = incomplete_fname.erase(F->getName());
(void)known; // TODO: assert(known); // llvmcall gets this wrong
module_for_fname[F->getName()] = m;
}
}
#if defined(USE_ORCJIT) || defined(USE_MCJIT)
// in the newer JITs, the shadow module is separate from the execution module
if (shadow)
jl_add_to_shadow(m);
#else
bool changes = jl_try_finalize(m);
while (changes) {
// this definitely isn't the most efficient, but it's only for the old LLVM 3.3 JIT
changes = false;
for (StringMap<Module*>::iterator MI = module_for_fname.begin(), ME = module_for_fname.end(); MI != ME; ++MI) {
changes |= jl_try_finalize(MI->second);
}
}
#endif
}
// helper function for adding a DLLImport (dlsym) address to the execution engine
// (for values created locally or in the sysimage, jl_emit_and_add_to_shadow is generally preferable)
#if JL_LLVM_VERSION >= 30500
void add_named_global(GlobalObject *gv, void *addr, bool dllimport)
#else
void add_named_global(GlobalValue *gv, void *addr, bool dllimport)
#endif
{
#ifdef _OS_WINDOWS_
// setting JL_DLLEXPORT correctly only matters when building a binary
// (global_proto will strip this from the JIT)
if (dllimport && imaging_mode) {
assert(gv->getLinkage() == GlobalValue::ExternalLinkage);
#if JL_LLVM_VERSION >= 30500
// add the __declspec(dllimport) attribute
gv->setDLLStorageClass(GlobalValue::DLLImportStorageClass);
#else
gv->setLinkage(GlobalValue::DLLImportLinkage);
#if defined(_P64)
// __imp_ variables are indirection pointers, so use malloc to simulate that
void **imp_addr = (void**)malloc(sizeof(void*));
*imp_addr = addr;
addr = (void*)imp_addr;
#endif
#endif
}
#endif // _OS_WINDOWS_
jl_ExecutionEngine->addGlobalMapping(gv, addr);
}
static std::vector<Constant*> jl_sysimg_gvars;
static std::vector<Constant*> jl_sysimg_fvars;
static std::map<void*, jl_value_llvm> jl_value_to_llvm;
// global variables to pointers are pretty common,
// so this method is available as a convenience for emitting them.
// for other types, the formula for implementation is straightforward:
// (see stringConstPtr, for an alternative example to the code below)
//
// if in imaging_mode, emit a GlobalVariable with the same name and an initializer to the shadow_module
// making it valid for emission and reloading in the sysimage
//
// then add a global mapping to the current value (usually from calloc'd space)
// to the execution engine to make it valid for the current session (with the current value)
void* jl_emit_and_add_to_shadow(GlobalVariable *gv, void *gvarinit)
{
PointerType *T = cast<PointerType>(gv->getType()->getElementType()); // pointer is the only supported type here
GlobalVariable *shadowvar = NULL;
#if defined(USE_MCJIT) || defined(USE_ORCJIT)
if (imaging_mode)
#endif
shadowvar = global_proto(gv, shadow_output);
if (shadowvar) {
shadowvar->setInitializer(ConstantPointerNull::get(T));
shadowvar->setLinkage(GlobalVariable::InternalLinkage);
addComdat(shadowvar);
if (imaging_mode && gvarinit) {
// make the pointer valid for future sessions
jl_sysimg_gvars.push_back(ConstantExpr::getBitCast(shadowvar, T_psize));
jl_value_llvm gv_struct;
gv_struct.gv = global_proto(gv);
gv_struct.index = jl_sysimg_gvars.size();
jl_value_to_llvm[gvarinit] = gv_struct;
}
}
// make the pointer valid for this session
#if defined(USE_MCJIT) || defined(USE_ORCJIT)
void *slot = calloc(1, sizeof(void*));
jl_ExecutionEngine->addGlobalMapping(gv, slot);
return slot;
#else
return jl_ExecutionEngine->getPointerToGlobal(shadowvar);
#endif
}
// Emit a slot in the system image to be filled at sysimg init time.
// Returns the global var. Fill `idx` with 1-base index in the sysimg gv.
// Use as an optimization for runtime constant addresses to have one less
// load. (Used only by threading).
GlobalVariable *jl_emit_sysimg_slot(Module *m, Type *typ, const char *name,
uintptr_t init, size_t &idx)
{
assert(imaging_mode);
// This is **NOT** a external variable or a normal global variable
// This is a special internal global slot with a special index
// in the global variable table.
GlobalVariable *gv = new GlobalVariable(*m, typ, false,
GlobalVariable::InternalLinkage,
ConstantPointerNull::get((PointerType*)typ), name);
addComdat(gv);
// make the pointer valid for this session
#if defined(USE_MCJIT) || defined(USE_ORCJIT)
auto p = new uintptr_t(init);
jl_ExecutionEngine->addGlobalMapping(gv, (void*)p);
#else
uintptr_t *p = (uintptr_t*)jl_ExecutionEngine->getPointerToGlobal(gv);
*p = init;
#endif
jl_sysimg_gvars.push_back(ConstantExpr::getBitCast(gv, T_psize));
idx = jl_sysimg_gvars.size();
return gv;
}
void* jl_get_global(GlobalVariable *gv)
{
#if defined(USE_MCJIT) || defined(USE_ORCJIT)
void *p = (void*)(intptr_t)jl_ExecutionEngine->getPointerToGlobalIfAvailable(gv);
#else
void *p = jl_ExecutionEngine->getPointerToGlobal(
shadow_output->getNamedValue(gv->getName()));
#endif
assert(p);
return p;
}
// clones the contents of the module `m` to the shadow_output collector
#if defined(USE_MCJIT) || defined(USE_ORCJIT)
void jl_add_to_shadow(Module *m)
{
#ifndef KEEP_BODIES
if (!imaging_mode)
return;
#endif
ValueToValueMapTy VMap;
std::unique_ptr<Module> clone(CloneModule(m, VMap));
for (Module::iterator I = clone->begin(), E = clone->end(); I != E; ++I) {
Function *F = &*I;
if (!F->isDeclaration()) {
F->setLinkage(Function::InternalLinkage);
addComdat(F);
}
}
jl_merge_module(shadow_output, std::move(clone));
}
#endif
#ifdef HAVE_CPUID
extern "C" {
extern void jl_cpuid(int32_t CPUInfo[4], int32_t InfoType);
}
#endif
static void jl_gen_llvm_globaldata(llvm::Module *mod, ValueToValueMapTy &VMap,
const char *sysimg_data, size_t sysimg_len)
{
ArrayType *gvars_type = ArrayType::get(T_psize, jl_sysimg_gvars.size());
addComdat(new GlobalVariable(*mod,
gvars_type,
true,
GlobalVariable::ExternalLinkage,
MapValue(ConstantArray::get(gvars_type, ArrayRef<Constant*>(jl_sysimg_gvars)), VMap),
"jl_sysimg_gvars"));
ArrayType *fvars_type = ArrayType::get(T_pvoidfunc, jl_sysimg_fvars.size());
addComdat(new GlobalVariable(*mod,
fvars_type,
true,
GlobalVariable::ExternalLinkage,
MapValue(ConstantArray::get(fvars_type, ArrayRef<Constant*>(jl_sysimg_fvars)), VMap),
"jl_sysimg_fvars"));
addComdat(new GlobalVariable(*mod,
T_size,
true,
GlobalVariable::ExternalLinkage,
ConstantInt::get(T_size, globalUnique+1),
"jl_globalUnique"));
#ifdef JULIA_ENABLE_THREADING
addComdat(new GlobalVariable(*mod,
T_size,
true,
GlobalVariable::ExternalLinkage,
ConstantInt::get(T_size, jltls_states_func_idx),
"jl_ptls_states_getter_idx"));
#endif
Constant *feature_string = ConstantDataArray::getString(jl_LLVMContext, jl_options.cpu_target);
addComdat(new GlobalVariable(*mod,
feature_string->getType(),
true,
GlobalVariable::ExternalLinkage,
feature_string,
"jl_sysimg_cpu_target"));
// reflect the address of the jl_RTLD_DEFAULT_handle variable
// back to the caller, so that we can check for consistency issues
GlobalValue *jlRTLD_DEFAULT_var = mod->getNamedValue("jl_RTLD_DEFAULT_handle");
addComdat(new GlobalVariable(*mod,
jlRTLD_DEFAULT_var->getType(),
true,
GlobalVariable::ExternalLinkage,
jlRTLD_DEFAULT_var,
"jl_RTLD_DEFAULT_handle_pointer"));
#ifdef HAVE_CPUID
// For native also store the cpuid
if (strcmp(jl_options.cpu_target,"native") == 0) {
uint32_t info[4];
jl_cpuid((int32_t*)info, 1);
addComdat(new GlobalVariable(*mod,
T_uint64,
true,
GlobalVariable::ExternalLinkage,
ConstantInt::get(T_uint64,((uint64_t)info[2])|(((uint64_t)info[3])<<32)),
"jl_sysimg_cpu_cpuid"));
}
#endif
if (sysimg_data) {
Constant *data = ConstantDataArray::get(jl_LLVMContext,
ArrayRef<uint8_t>((const unsigned char*)sysimg_data, sysimg_len));
addComdat(new GlobalVariable(*mod, data->getType(), true,
GlobalVariable::ExternalLinkage,
data, "jl_system_image_data"));
Constant *len = ConstantInt::get(T_size, sysimg_len);
addComdat(new GlobalVariable(*mod, len->getType(), true,
GlobalVariable::ExternalLinkage,
len, "jl_system_image_size"));
}
}
// takes the running content that has collected in the shadow module and dump it to disk
// this builds the object file portion of the sysimage files for fast startup
extern "C"
void jl_dump_native(const char *bc_fname, const char *obj_fname, const char *sysimg_data, size_t sysimg_len)
{
JL_TIMING(NATIVE_DUMP);
assert(imaging_mode);
// We don't want to use MCJIT's target machine because
// it uses the large code model and we may potentially
// want less optimizations there.
Triple TheTriple = Triple(jl_TargetMachine->getTargetTriple());
// make sure to emit the native object format, even if FORCE_ELF was set in codegen
#if defined(_OS_WINDOWS_)
#if JL_LLVM_VERSION >= 30500
TheTriple.setObjectFormat(Triple::COFF);
#else
TheTriple.setEnvironment(Triple::UnknownEnvironment);
#endif
#elif defined(_OS_DARWIN_)
#if JL_LLVM_VERSION >= 30500
TheTriple.setObjectFormat(Triple::MachO);
#else
TheTriple.setEnvironment(Triple::MachO);
#endif
#endif
#if JL_LLVM_VERSION >= 30500
std::unique_ptr<TargetMachine>
#else
OwningPtr<TargetMachine>
#endif
TM(jl_TargetMachine->getTarget().createTargetMachine(
TheTriple.getTriple(),
jl_TargetMachine->getTargetCPU(),
jl_TargetMachine->getTargetFeatureString(),
jl_TargetMachine->Options,
#if defined(_OS_LINUX_) || defined(_OS_FREEBSD_)
Reloc::PIC_,
#elif JL_LLVM_VERSION >= 30900
Optional<Reloc::Model>(),
#else
Reloc::Default,
#endif
CodeModel::Default,
CodeGenOpt::Aggressive // -O3 TODO: respect command -O0 flag?
));
#if JL_LLVM_VERSION >= 30700
legacy::PassManager PM;
#else
PassManager PM;
#endif
#if JL_LLVM_VERSION < 30700
PM.add(new TargetLibraryInfo(Triple(TM->getTargetTriple())));
#else
PM.add(new TargetLibraryInfoWrapperPass(Triple(TM->getTargetTriple())));
#endif
// set up optimization passes
#if JL_LLVM_VERSION >= 30700
// No DataLayout pass needed anymore.
#elif JL_LLVM_VERSION >= 30600
PM.add(new DataLayoutPass());
#elif JL_LLVM_VERSION >= 30500
PM.add(new DataLayoutPass(*jl_ExecutionEngine->getDataLayout()));
#else
PM.add(new DataLayout(*jl_ExecutionEngine->getDataLayout()));
#endif
addOptimizationPasses(&PM);
std::unique_ptr<raw_fd_ostream> bc_OS;
std::unique_ptr<raw_fd_ostream> obj_OS;
#if JL_LLVM_VERSION >= 30700 // 3.7 simplified formatted output; just use the raw stream alone
std::unique_ptr<raw_fd_ostream> &bc_FOS = bc_OS;
std::unique_ptr<raw_fd_ostream> &obj_FOS = obj_OS;
#else
std::unique_ptr<formatted_raw_ostream> bc_FOS;
std::unique_ptr<formatted_raw_ostream> obj_FOS;
#endif
if (bc_fname) {
#if JL_LLVM_VERSION >= 30500
// call output handler directly to avoid special case handling of `-` filename
int FD;
std::error_code EC = sys::fs::openFileForWrite(bc_fname, FD, sys::fs::F_None);
bc_OS.reset(new raw_fd_ostream(FD, true));
std::string err;
if (EC)
err = "ERROR: failed to open --output-bc file '" + std::string(bc_fname) + "': " + EC.message();
#else
std::string err;
bc_OS.reset(new raw_fd_ostream(bc_fname, err, raw_fd_ostream::F_Binary));
#endif
if (!err.empty())
jl_safe_printf("%s\n", err.c_str());
else {
#if JL_LLVM_VERSION < 30700
bc_FOS.reset(new formatted_raw_ostream(*bc_OS.get()));
#endif
PM.add(createBitcodeWriterPass(*bc_FOS.get())); // Unroll small loops
}
}
if (obj_fname) {
#if JL_LLVM_VERSION >= 30500
// call output handler directly to avoid special case handling of `-` filename
int FD;
std::error_code EC = sys::fs::openFileForWrite(obj_fname, FD, sys::fs::F_None);
obj_OS.reset(new raw_fd_ostream(FD, true));
std::string err;
if (EC)
err = "ERROR: failed to open --output-o file '" + std::string(obj_fname) + "': " + EC.message();
#else
std::string err;
obj_OS.reset(new raw_fd_ostream(obj_fname, err, raw_fd_ostream::F_Binary));
#endif
if (!err.empty())
jl_safe_printf("%s\n", err.c_str());
else {
#if JL_LLVM_VERSION < 30700
obj_FOS.reset(new formatted_raw_ostream(*obj_OS.get()));
#endif
if (TM->addPassesToEmitFile(PM, *obj_FOS.get(), TargetMachine::CGFT_ObjectFile, false)) {
jl_safe_printf("ERROR: target does not support generation of object files\n");
}
}
}
ValueToValueMapTy VMap;
#if defined(USE_MCJIT) || defined(USE_ORCJIT)
// now copy the module (if using the old JIT), since PM.run may modify it
Module *clone = shadow_output;
#else
Module *clone = CloneModule(shadow_output, VMap);
#endif
#if JL_LLVM_VERSION >= 30700
// Reset the target triple to make sure it matches the new target machine
clone->setTargetTriple(TM->getTargetTriple().str());
#if JL_LLVM_VERSION >= 30800
clone->setDataLayout(TM->createDataLayout());
#else
clone->setDataLayout(TM->getDataLayout()->getStringRepresentation());
#endif
#endif
// add metadata information
jl_gen_llvm_globaldata(clone, VMap, sysimg_data, sysimg_len);
// do the actual work
PM.run(*clone);
#if !defined(USE_MCJIT) && !defined(USE_ORCJIT)
delete clone;
#endif
imaging_mode = false;
}
extern "C" int32_t jl_assign_functionID(void *function)
{
// give the function an index in the constant lookup table
assert(imaging_mode);
if (function == NULL)
return 0;
jl_sysimg_fvars.push_back(ConstantExpr::getBitCast(
shadow_output->getNamedValue(((Function*)function)->getName()),
T_pvoidfunc));
return jl_sysimg_fvars.size();
}
extern "C" int32_t jl_get_llvm_gv(jl_value_t *p)
{
// map a jl_value_t memory location to a GlobalVariable
std::map<void*, jl_value_llvm>::iterator it;
it = jl_value_to_llvm.find(p);
if (it == jl_value_to_llvm.end())
return 0;
return it->second.index;
}
GlobalVariable *jl_get_global_for(const char *cname, void *addr, Module *M)
{
// emit a GlobalVariable for a jl_value_t named "cname"
std::map<void*, jl_value_llvm>::iterator it;
// first see if there already is a GlobalVariable for this address
it = jl_value_to_llvm.find(addr);
if (it != jl_value_to_llvm.end())
return prepare_global((llvm::GlobalVariable*)it->second.gv, M);
std::stringstream gvname;
gvname << cname << globalUnique++;
// no existing GlobalVariable, create one and store it
GlobalVariable *gv = new GlobalVariable(*M, T_pjlvalue,
false, GlobalVariable::ExternalLinkage,
NULL, gvname.str());
*(void**)jl_emit_and_add_to_shadow(gv, addr) = addr;
return gv;
}