llvm-6502/lib/ExecutionEngine/JIT/JIT.cpp
Nicolas Geoffray d046fc61ac Add support for JIT exceptions on Darwin. Since we're dealing with libgcc,
whose darwin code was written after the ability to dynamically register frames,
we need to do special hacks to make things work.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55507 91177308-0d34-0410-b5e6-96231b3b80d8
2008-08-28 22:34:49 +00:00

593 lines
20 KiB
C++

//===-- JIT.cpp - LLVM Just in Time Compiler ------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This tool implements a just-in-time compiler for LLVM, allowing direct
// execution of LLVM bitcode in an efficient manner.
//
//===----------------------------------------------------------------------===//
#include "JIT.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
#include "llvm/GlobalVariable.h"
#include "llvm/Instructions.h"
#include "llvm/ModuleProvider.h"
#include "llvm/CodeGen/MachineCodeEmitter.h"
#include "llvm/ExecutionEngine/GenericValue.h"
#include "llvm/Support/MutexGuard.h"
#include "llvm/System/DynamicLibrary.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetJITInfo.h"
#include "llvm/Config/config.h"
using namespace llvm;
#ifdef __APPLE__
// Apple gcc defaults to -fuse-cxa-atexit (i.e. calls __cxa_atexit instead
// of atexit). It passes the address of linker generated symbol __dso_handle
// to the function.
// This configuration change happened at version 5330.
# include <AvailabilityMacros.h>
# if defined(MAC_OS_X_VERSION_10_4) && \
((MAC_OS_X_VERSION_MIN_REQUIRED > MAC_OS_X_VERSION_10_4) || \
(MAC_OS_X_VERSION_MIN_REQUIRED == MAC_OS_X_VERSION_10_4 && \
__APPLE_CC__ >= 5330))
# ifndef HAVE___DSO_HANDLE
# define HAVE___DSO_HANDLE 1
# endif
# endif
#endif
#if HAVE___DSO_HANDLE
extern void *__dso_handle __attribute__ ((__visibility__ ("hidden")));
#endif
namespace {
static struct RegisterJIT {
RegisterJIT() { JIT::Register(); }
} JITRegistrator;
}
namespace llvm {
void LinkInJIT() {
}
}
#if defined (__GNUC__)
// libgcc defines the __register_frame function to dynamically register new
// dwarf frames for exception handling. This functionality is not portable
// across compilers and is only provided by GCC. We use the __register_frame
// function here so that code generated by the JIT cooperates with the unwinding
// runtime of libgcc. When JITting with exception handling enable, LLVM
// generates dwarf frames and registers it to libgcc with __register_frame.
//
// The __register_frame function works with Linux.
//
// Unfortunately, this functionality seems to be in libgcc after the unwinding
// library of libgcc for darwin was written. The code for darwin overwrites the
// value updated by __register_frame with a value fetched with "keymgr".
// "keymgr" is an obsolete functionality, which should be rewritten some day.
// In the meantime, since "keymgr" is on all libgccs shipped with apple-gcc, we
// need a workaround in LLVM which uses the "keymgr" to dynamically modify the
// values of an opaque key, used by libgcc to find dwarf tables.
extern "C" void __register_frame(void*);
#if defined (__APPLE__)
namespace {
// LibgccObject - This is the structure defined in libgcc. There is no #include
// provided for this structure, so we also define it here. libgcc calls it
// "struct object". The structure is undocumented in libgcc.
struct LibgccObject {
void *unused1;
void *unused2;
void *unused3;
/// frame - Pointer to the exception table.
void *frame;
/// encoding - The encoding of the object?
union {
struct {
unsigned long sorted : 1;
unsigned long from_array : 1;
unsigned long mixed_encoding : 1;
unsigned long encoding : 8;
unsigned long count : 21;
} b;
size_t i;
} encoding;
/// fde_end - libgcc defines this field only if some macro is defined. We
/// include this field even if it may not there, to make libgcc happy.
char *fde_end;
/// next - At least we know it's a chained list!
struct LibgccObject *next;
};
// "kemgr" stuff. Apparently, all frame tables are stored there.
extern "C" void _keymgr_set_and_unlock_processwide_ptr(int, void *);
extern "C" void *_keymgr_get_and_lock_processwide_ptr(int);
#define KEYMGR_GCC3_DW2_OBJ_LIST 302 /* Dwarf2 object list */
/// LibgccObjectInfo - libgcc defines this struct as km_object_info. It
/// probably contains all dwarf tables that are loaded.
struct LibgccObjectInfo {
/// seenObjects - LibgccObjects already parsed by the unwinding runtime.
///
struct LibgccObject* seenObjects;
/// unseenObjects - LibgccObjects not parsed yet by the unwinding runtime.
///
struct LibgccObject* unseenObjects;
unsigned unused[2];
};
// for DW_EH_PE_omit
#include "llvm/Support/Dwarf.h"
/// darwin_register_frame - Since __register_frame does not work with darwin's
/// libgcc,we provide our own function, which "tricks" libgcc by modifying the
/// "Dwarf2 object list" key.
void DarwinRegisterFrame(void* FrameBegin) {
// Get the key.
struct LibgccObjectInfo* LOI = (struct LibgccObjectInfo*)
_keymgr_get_and_lock_processwide_ptr(KEYMGR_GCC3_DW2_OBJ_LIST);
// Allocate a new LibgccObject to represent this frame. Deallocation of this
// object may be impossible: since darwin code in libgcc was written after
// the ability to dynamically register frames, things may crash if we
// deallocate it.
struct LibgccObject* ob = (struct LibgccObject*)
malloc(sizeof(struct LibgccObject));
// Do like libgcc for the values of the field.
ob->unused1 = (void *)-1;
ob->unused2 = 0;
ob->unused3 = 0;
ob->frame = FrameBegin;
ob->encoding.i = 0;
ob->encoding.b.encoding = llvm::dwarf::DW_EH_PE_omit;
// Put the info on both places, as libgcc uses the first or the the second
// field. Note that we rely on having two pointers here. If fde_end was a
// char, things would get complicated.
ob->fde_end = (char*)LOI->unseenObjects;
ob->next = LOI->unseenObjects;
// Update the key's unseenObjects list.
LOI->unseenObjects = ob;
// Finally update the "key". Apparently, libgcc requires it.
_keymgr_set_and_unlock_processwide_ptr(KEYMGR_GCC3_DW2_OBJ_LIST,
LOI);
}
}
#endif // __APPLE__
#endif // __GNUC__
/// createJIT - This is the factory method for creating a JIT for the current
/// machine, it does not fall back to the interpreter. This takes ownership
/// of the module provider.
ExecutionEngine *ExecutionEngine::createJIT(ModuleProvider *MP,
std::string *ErrorStr,
JITMemoryManager *JMM,
bool Fast) {
ExecutionEngine *EE = JIT::createJIT(MP, ErrorStr, JMM, Fast);
if (!EE) return 0;
// Make sure we can resolve symbols in the program as well. The zero arg
// to the function tells DynamicLibrary to load the program, not a library.
sys::DynamicLibrary::LoadLibraryPermanently(0, ErrorStr);
return EE;
}
JIT::JIT(ModuleProvider *MP, TargetMachine &tm, TargetJITInfo &tji,
JITMemoryManager *JMM, bool Fast)
: ExecutionEngine(MP), TM(tm), TJI(tji) {
setTargetData(TM.getTargetData());
jitstate = new JITState(MP);
// Initialize MCE
MCE = createEmitter(*this, JMM);
// Add target data
MutexGuard locked(lock);
FunctionPassManager &PM = jitstate->getPM(locked);
PM.add(new TargetData(*TM.getTargetData()));
// Turn the machine code intermediate representation into bytes in memory that
// may be executed.
if (TM.addPassesToEmitMachineCode(PM, *MCE, Fast)) {
cerr << "Target does not support machine code emission!\n";
abort();
}
// Register routine for informing unwinding runtime about new EH frames
#if defined(__GNUC__)
#if defined(__APPLE__)
struct LibgccObjectInfo* LOI = (struct LibgccObjectInfo*)
_keymgr_get_and_lock_processwide_ptr(KEYMGR_GCC3_DW2_OBJ_LIST);
// The key is created on demand, and libgcc creates it the first time an
// exception occurs. Since we need the key to register frames, we create
// it now.
if (!LOI) {
LOI = (LibgccObjectInfo*)malloc(sizeof(struct LibgccObjectInfo));
_keymgr_set_and_unlock_processwide_ptr(KEYMGR_GCC3_DW2_OBJ_LIST,
LOI);
}
InstallExceptionTableRegister(DarwinRegisterFrame);
#else
InstallExceptionTableRegister(__register_frame);
#endif // __APPLE__
#endif // __GNUC__
// Initialize passes.
PM.doInitialization();
}
JIT::~JIT() {
delete jitstate;
delete MCE;
delete &TM;
}
/// addModuleProvider - Add a new ModuleProvider to the JIT. If we previously
/// removed the last ModuleProvider, we need re-initialize jitstate with a valid
/// ModuleProvider.
void JIT::addModuleProvider(ModuleProvider *MP) {
MutexGuard locked(lock);
if (Modules.empty()) {
assert(!jitstate && "jitstate should be NULL if Modules vector is empty!");
jitstate = new JITState(MP);
FunctionPassManager &PM = jitstate->getPM(locked);
PM.add(new TargetData(*TM.getTargetData()));
// Turn the machine code intermediate representation into bytes in memory
// that may be executed.
if (TM.addPassesToEmitMachineCode(PM, *MCE, false /*fast*/)) {
cerr << "Target does not support machine code emission!\n";
abort();
}
// Initialize passes.
PM.doInitialization();
}
ExecutionEngine::addModuleProvider(MP);
}
/// removeModuleProvider - If we are removing the last ModuleProvider,
/// invalidate the jitstate since the PassManager it contains references a
/// released ModuleProvider.
Module *JIT::removeModuleProvider(ModuleProvider *MP, std::string *E) {
Module *result = ExecutionEngine::removeModuleProvider(MP, E);
MutexGuard locked(lock);
if (Modules.empty()) {
delete jitstate;
jitstate = 0;
}
return result;
}
/// run - Start execution with the specified function and arguments.
///
GenericValue JIT::runFunction(Function *F,
const std::vector<GenericValue> &ArgValues) {
assert(F && "Function *F was null at entry to run()");
void *FPtr = getPointerToFunction(F);
assert(FPtr && "Pointer to fn's code was null after getPointerToFunction");
const FunctionType *FTy = F->getFunctionType();
const Type *RetTy = FTy->getReturnType();
assert((FTy->getNumParams() <= ArgValues.size() || FTy->isVarArg()) &&
"Too many arguments passed into function!");
assert(FTy->getNumParams() == ArgValues.size() &&
"This doesn't support passing arguments through varargs (yet)!");
// Handle some common cases first. These cases correspond to common `main'
// prototypes.
if (RetTy == Type::Int32Ty || RetTy == Type::VoidTy) {
switch (ArgValues.size()) {
case 3:
if (FTy->getParamType(0) == Type::Int32Ty &&
isa<PointerType>(FTy->getParamType(1)) &&
isa<PointerType>(FTy->getParamType(2))) {
int (*PF)(int, char **, const char **) =
(int(*)(int, char **, const char **))(intptr_t)FPtr;
// Call the function.
GenericValue rv;
rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue(),
(char **)GVTOP(ArgValues[1]),
(const char **)GVTOP(ArgValues[2])));
return rv;
}
break;
case 2:
if (FTy->getParamType(0) == Type::Int32Ty &&
isa<PointerType>(FTy->getParamType(1))) {
int (*PF)(int, char **) = (int(*)(int, char **))(intptr_t)FPtr;
// Call the function.
GenericValue rv;
rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue(),
(char **)GVTOP(ArgValues[1])));
return rv;
}
break;
case 1:
if (FTy->getNumParams() == 1 &&
FTy->getParamType(0) == Type::Int32Ty) {
GenericValue rv;
int (*PF)(int) = (int(*)(int))(intptr_t)FPtr;
rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue()));
return rv;
}
break;
}
}
// Handle cases where no arguments are passed first.
if (ArgValues.empty()) {
GenericValue rv;
switch (RetTy->getTypeID()) {
default: assert(0 && "Unknown return type for function call!");
case Type::IntegerTyID: {
unsigned BitWidth = cast<IntegerType>(RetTy)->getBitWidth();
if (BitWidth == 1)
rv.IntVal = APInt(BitWidth, ((bool(*)())(intptr_t)FPtr)());
else if (BitWidth <= 8)
rv.IntVal = APInt(BitWidth, ((char(*)())(intptr_t)FPtr)());
else if (BitWidth <= 16)
rv.IntVal = APInt(BitWidth, ((short(*)())(intptr_t)FPtr)());
else if (BitWidth <= 32)
rv.IntVal = APInt(BitWidth, ((int(*)())(intptr_t)FPtr)());
else if (BitWidth <= 64)
rv.IntVal = APInt(BitWidth, ((int64_t(*)())(intptr_t)FPtr)());
else
assert(0 && "Integer types > 64 bits not supported");
return rv;
}
case Type::VoidTyID:
rv.IntVal = APInt(32, ((int(*)())(intptr_t)FPtr)());
return rv;
case Type::FloatTyID:
rv.FloatVal = ((float(*)())(intptr_t)FPtr)();
return rv;
case Type::DoubleTyID:
rv.DoubleVal = ((double(*)())(intptr_t)FPtr)();
return rv;
case Type::X86_FP80TyID:
case Type::FP128TyID:
case Type::PPC_FP128TyID:
assert(0 && "long double not supported yet");
return rv;
case Type::PointerTyID:
return PTOGV(((void*(*)())(intptr_t)FPtr)());
}
}
// Okay, this is not one of our quick and easy cases. Because we don't have a
// full FFI, we have to codegen a nullary stub function that just calls the
// function we are interested in, passing in constants for all of the
// arguments. Make this function and return.
// First, create the function.
FunctionType *STy=FunctionType::get(RetTy, std::vector<const Type*>(), false);
Function *Stub = Function::Create(STy, Function::InternalLinkage, "",
F->getParent());
// Insert a basic block.
BasicBlock *StubBB = BasicBlock::Create("", Stub);
// Convert all of the GenericValue arguments over to constants. Note that we
// currently don't support varargs.
SmallVector<Value*, 8> Args;
for (unsigned i = 0, e = ArgValues.size(); i != e; ++i) {
Constant *C = 0;
const Type *ArgTy = FTy->getParamType(i);
const GenericValue &AV = ArgValues[i];
switch (ArgTy->getTypeID()) {
default: assert(0 && "Unknown argument type for function call!");
case Type::IntegerTyID:
C = ConstantInt::get(AV.IntVal);
break;
case Type::FloatTyID:
C = ConstantFP::get(APFloat(AV.FloatVal));
break;
case Type::DoubleTyID:
C = ConstantFP::get(APFloat(AV.DoubleVal));
break;
case Type::PPC_FP128TyID:
case Type::X86_FP80TyID:
case Type::FP128TyID:
C = ConstantFP::get(APFloat(AV.IntVal));
break;
case Type::PointerTyID:
void *ArgPtr = GVTOP(AV);
if (sizeof(void*) == 4)
C = ConstantInt::get(Type::Int32Ty, (int)(intptr_t)ArgPtr);
else
C = ConstantInt::get(Type::Int64Ty, (intptr_t)ArgPtr);
C = ConstantExpr::getIntToPtr(C, ArgTy); // Cast the integer to pointer
break;
}
Args.push_back(C);
}
CallInst *TheCall = CallInst::Create(F, Args.begin(), Args.end(),
"", StubBB);
TheCall->setTailCall();
if (TheCall->getType() != Type::VoidTy)
ReturnInst::Create(TheCall, StubBB); // Return result of the call.
else
ReturnInst::Create(StubBB); // Just return void.
// Finally, return the value returned by our nullary stub function.
return runFunction(Stub, std::vector<GenericValue>());
}
/// runJITOnFunction - Run the FunctionPassManager full of
/// just-in-time compilation passes on F, hopefully filling in
/// GlobalAddress[F] with the address of F's machine code.
///
void JIT::runJITOnFunction(Function *F) {
static bool isAlreadyCodeGenerating = false;
MutexGuard locked(lock);
assert(!isAlreadyCodeGenerating && "Error: Recursive compilation detected!");
// JIT the function
isAlreadyCodeGenerating = true;
jitstate->getPM(locked).run(*F);
isAlreadyCodeGenerating = false;
// If the function referred to a global variable that had not yet been
// emitted, it allocates memory for the global, but doesn't emit it yet. Emit
// all of these globals now.
while (!jitstate->getPendingGlobals(locked).empty()) {
const GlobalVariable *GV = jitstate->getPendingGlobals(locked).back();
jitstate->getPendingGlobals(locked).pop_back();
EmitGlobalVariable(GV);
}
}
/// getPointerToFunction - This method is used to get the address of the
/// specified function, compiling it if neccesary.
///
void *JIT::getPointerToFunction(Function *F) {
if (void *Addr = getPointerToGlobalIfAvailable(F))
return Addr; // Check if function already code gen'd
// Make sure we read in the function if it exists in this Module.
if (F->hasNotBeenReadFromBitcode()) {
// Determine the module provider this function is provided by.
Module *M = F->getParent();
ModuleProvider *MP = 0;
for (unsigned i = 0, e = Modules.size(); i != e; ++i) {
if (Modules[i]->getModule() == M) {
MP = Modules[i];
break;
}
}
assert(MP && "Function isn't in a module we know about!");
std::string ErrorMsg;
if (MP->materializeFunction(F, &ErrorMsg)) {
cerr << "Error reading function '" << F->getName()
<< "' from bitcode file: " << ErrorMsg << "\n";
abort();
}
}
if (void *Addr = getPointerToGlobalIfAvailable(F)) {
return Addr;
}
MutexGuard locked(lock);
if (F->isDeclaration()) {
void *Addr = getPointerToNamedFunction(F->getName());
addGlobalMapping(F, Addr);
return Addr;
}
runJITOnFunction(F);
void *Addr = getPointerToGlobalIfAvailable(F);
assert(Addr && "Code generation didn't add function to GlobalAddress table!");
return Addr;
}
/// getOrEmitGlobalVariable - Return the address of the specified global
/// variable, possibly emitting it to memory if needed. This is used by the
/// Emitter.
void *JIT::getOrEmitGlobalVariable(const GlobalVariable *GV) {
MutexGuard locked(lock);
void *Ptr = getPointerToGlobalIfAvailable(GV);
if (Ptr) return Ptr;
// If the global is external, just remember the address.
if (GV->isDeclaration()) {
#if HAVE___DSO_HANDLE
if (GV->getName() == "__dso_handle")
return (void*)&__dso_handle;
#endif
Ptr = sys::DynamicLibrary::SearchForAddressOfSymbol(GV->getName().c_str());
if (Ptr == 0) {
cerr << "Could not resolve external global address: "
<< GV->getName() << "\n";
abort();
addGlobalMapping(GV, Ptr);
}
} else {
// If the global hasn't been emitted to memory yet, allocate space and
// emit it into memory. It goes in the same array as the generated
// code, jump tables, etc.
const Type *GlobalType = GV->getType()->getElementType();
size_t S = getTargetData()->getABITypeSize(GlobalType);
size_t A = getTargetData()->getPreferredAlignment(GV);
Ptr = MCE->allocateSpace(S, A);
addGlobalMapping(GV, Ptr);
EmitGlobalVariable(GV);
}
return Ptr;
}
/// recompileAndRelinkFunction - This method is used to force a function
/// which has already been compiled, to be compiled again, possibly
/// after it has been modified. Then the entry to the old copy is overwritten
/// with a branch to the new copy. If there was no old copy, this acts
/// just like JIT::getPointerToFunction().
///
void *JIT::recompileAndRelinkFunction(Function *F) {
void *OldAddr = getPointerToGlobalIfAvailable(F);
// If it's not already compiled there is no reason to patch it up.
if (OldAddr == 0) { return getPointerToFunction(F); }
// Delete the old function mapping.
addGlobalMapping(F, 0);
// Recodegen the function
runJITOnFunction(F);
// Update state, forward the old function to the new function.
void *Addr = getPointerToGlobalIfAvailable(F);
assert(Addr && "Code generation didn't add function to GlobalAddress table!");
TJI.replaceMachineCodeForFunction(OldAddr, Addr);
return Addr;
}