llvm-6502/lib/ExecutionEngine/JIT/JITEmitter.cpp
Jim Grosbach cce6c297c5 On Darwin ARM, memory needs special handling to do JIT. This patch expands
this handling to work properly for modifying stub functions, relocations
back to entry points after JIT compilation, etc..


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57013 91177308-0d34-0410-b5e6-96231b3b80d8
2008-10-03 16:17:20 +00:00

1186 lines
43 KiB
C++

//===-- JITEmitter.cpp - Write machine code to executable memory ----------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines a MachineCodeEmitter object that is used by the JIT to
// write machine code to memory and remember where relocatable values are.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "jit"
#include "JIT.h"
#include "JITDwarfEmitter.h"
#include "llvm/Constants.h"
#include "llvm/Module.h"
#include "llvm/DerivedTypes.h"
#include "llvm/CodeGen/MachineCodeEmitter.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineRelocation.h"
#include "llvm/ExecutionEngine/JITMemoryManager.h"
#include "llvm/ExecutionEngine/GenericValue.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetJITInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/MutexGuard.h"
#include "llvm/System/Disassembler.h"
#include "llvm/System/Memory.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/ADT/Statistic.h"
#include <algorithm>
#include <set>
using namespace llvm;
STATISTIC(NumBytes, "Number of bytes of machine code compiled");
STATISTIC(NumRelos, "Number of relocations applied");
static JIT *TheJIT = 0;
//===----------------------------------------------------------------------===//
// JIT lazy compilation code.
//
namespace {
class JITResolverState {
private:
/// FunctionToStubMap - Keep track of the stub created for a particular
/// function so that we can reuse them if necessary.
std::map<Function*, void*> FunctionToStubMap;
/// StubToFunctionMap - Keep track of the function that each stub
/// corresponds to.
std::map<void*, Function*> StubToFunctionMap;
/// GlobalToLazyPtrMap - Keep track of the lazy pointer created for a
/// particular GlobalVariable so that we can reuse them if necessary.
std::map<GlobalValue*, void*> GlobalToLazyPtrMap;
public:
std::map<Function*, void*>& getFunctionToStubMap(const MutexGuard& locked) {
assert(locked.holds(TheJIT->lock));
return FunctionToStubMap;
}
std::map<void*, Function*>& getStubToFunctionMap(const MutexGuard& locked) {
assert(locked.holds(TheJIT->lock));
return StubToFunctionMap;
}
std::map<GlobalValue*, void*>&
getGlobalToLazyPtrMap(const MutexGuard& locked) {
assert(locked.holds(TheJIT->lock));
return GlobalToLazyPtrMap;
}
};
/// JITResolver - Keep track of, and resolve, call sites for functions that
/// have not yet been compiled.
class JITResolver {
/// LazyResolverFn - The target lazy resolver function that we actually
/// rewrite instructions to use.
TargetJITInfo::LazyResolverFn LazyResolverFn;
JITResolverState state;
/// ExternalFnToStubMap - This is the equivalent of FunctionToStubMap for
/// external functions.
std::map<void*, void*> ExternalFnToStubMap;
//map addresses to indexes in the GOT
std::map<void*, unsigned> revGOTMap;
unsigned nextGOTIndex;
static JITResolver *TheJITResolver;
public:
explicit JITResolver(JIT &jit) : nextGOTIndex(0) {
TheJIT = &jit;
LazyResolverFn = jit.getJITInfo().getLazyResolverFunction(JITCompilerFn);
assert(TheJITResolver == 0 && "Multiple JIT resolvers?");
TheJITResolver = this;
}
~JITResolver() {
TheJITResolver = 0;
}
/// getFunctionStub - This returns a pointer to a function stub, creating
/// one on demand as needed.
void *getFunctionStub(Function *F);
/// getExternalFunctionStub - Return a stub for the function at the
/// specified address, created lazily on demand.
void *getExternalFunctionStub(void *FnAddr);
/// getGlobalValueLazyPtr - Return a lazy pointer containing the specified
/// GV address.
void *getGlobalValueLazyPtr(GlobalValue *V, void *GVAddress);
/// AddCallbackAtLocation - If the target is capable of rewriting an
/// instruction without the use of a stub, record the location of the use so
/// we know which function is being used at the location.
void *AddCallbackAtLocation(Function *F, void *Location) {
MutexGuard locked(TheJIT->lock);
/// Get the target-specific JIT resolver function.
state.getStubToFunctionMap(locked)[Location] = F;
return (void*)(intptr_t)LazyResolverFn;
}
/// getGOTIndexForAddress - Return a new or existing index in the GOT for
/// an address. This function only manages slots, it does not manage the
/// contents of the slots or the memory associated with the GOT.
unsigned getGOTIndexForAddr(void *addr);
/// JITCompilerFn - This function is called to resolve a stub to a compiled
/// address. If the LLVM Function corresponding to the stub has not yet
/// been compiled, this function compiles it first.
static void *JITCompilerFn(void *Stub);
};
}
JITResolver *JITResolver::TheJITResolver = 0;
/// getFunctionStub - This returns a pointer to a function stub, creating
/// one on demand as needed.
void *JITResolver::getFunctionStub(Function *F) {
MutexGuard locked(TheJIT->lock);
// If we already have a stub for this function, recycle it.
void *&Stub = state.getFunctionToStubMap(locked)[F];
if (Stub) return Stub;
// Call the lazy resolver function unless we already KNOW it is an external
// function, in which case we just skip the lazy resolution step.
void *Actual = (void*)(intptr_t)LazyResolverFn;
if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode())
Actual = TheJIT->getPointerToFunction(F);
// Otherwise, codegen a new stub. For now, the stub will call the lazy
// resolver function.
Stub = TheJIT->getJITInfo().emitFunctionStub(F, Actual,
*TheJIT->getCodeEmitter());
if (Actual != (void*)(intptr_t)LazyResolverFn) {
// If we are getting the stub for an external function, we really want the
// address of the stub in the GlobalAddressMap for the JIT, not the address
// of the external function.
TheJIT->updateGlobalMapping(F, Stub);
}
DOUT << "JIT: Stub emitted at [" << Stub << "] for function '"
<< F->getName() << "'\n";
// Finally, keep track of the stub-to-Function mapping so that the
// JITCompilerFn knows which function to compile!
state.getStubToFunctionMap(locked)[Stub] = F;
return Stub;
}
/// getGlobalValueLazyPtr - Return a lazy pointer containing the specified
/// GV address.
void *JITResolver::getGlobalValueLazyPtr(GlobalValue *GV, void *GVAddress) {
MutexGuard locked(TheJIT->lock);
// If we already have a stub for this global variable, recycle it.
void *&LazyPtr = state.getGlobalToLazyPtrMap(locked)[GV];
if (LazyPtr) return LazyPtr;
// Otherwise, codegen a new lazy pointer.
LazyPtr = TheJIT->getJITInfo().emitGlobalValueLazyPtr(GV, GVAddress,
*TheJIT->getCodeEmitter());
DOUT << "JIT: Stub emitted at [" << LazyPtr << "] for GV '"
<< GV->getName() << "'\n";
return LazyPtr;
}
/// getExternalFunctionStub - Return a stub for the function at the
/// specified address, created lazily on demand.
void *JITResolver::getExternalFunctionStub(void *FnAddr) {
// If we already have a stub for this function, recycle it.
void *&Stub = ExternalFnToStubMap[FnAddr];
if (Stub) return Stub;
Stub = TheJIT->getJITInfo().emitFunctionStub(0, FnAddr,
*TheJIT->getCodeEmitter());
DOUT << "JIT: Stub emitted at [" << Stub
<< "] for external function at '" << FnAddr << "'\n";
return Stub;
}
unsigned JITResolver::getGOTIndexForAddr(void* addr) {
unsigned idx = revGOTMap[addr];
if (!idx) {
idx = ++nextGOTIndex;
revGOTMap[addr] = idx;
DOUT << "Adding GOT entry " << idx << " for addr " << addr << "\n";
}
return idx;
}
/// JITCompilerFn - This function is called when a lazy compilation stub has
/// been entered. It looks up which function this stub corresponds to, compiles
/// it if necessary, then returns the resultant function pointer.
void *JITResolver::JITCompilerFn(void *Stub) {
JITResolver &JR = *TheJITResolver;
Function* F = 0;
void* ActualPtr = 0;
{
// Only lock for getting the Function. The call getPointerToFunction made
// in this function might trigger function materializing, which requires
// JIT lock to be unlocked.
MutexGuard locked(TheJIT->lock);
// The address given to us for the stub may not be exactly right, it might be
// a little bit after the stub. As such, use upper_bound to find it.
std::map<void*, Function*>::iterator I =
JR.state.getStubToFunctionMap(locked).upper_bound(Stub);
assert(I != JR.state.getStubToFunctionMap(locked).begin() &&
"This is not a known stub!");
F = (--I)->second;
ActualPtr = I->first;
}
// If we have already code generated the function, just return the address.
void *Result = TheJIT->getPointerToGlobalIfAvailable(F);
if (!Result) {
// Otherwise we don't have it, do lazy compilation now.
// If lazy compilation is disabled, emit a useful error message and abort.
if (TheJIT->isLazyCompilationDisabled()) {
cerr << "LLVM JIT requested to do lazy compilation of function '"
<< F->getName() << "' when lazy compiles are disabled!\n";
abort();
}
// We might like to remove the stub from the StubToFunction map.
// We can't do that! Multiple threads could be stuck, waiting to acquire the
// lock above. As soon as the 1st function finishes compiling the function,
// the next one will be released, and needs to be able to find the function
// it needs to call.
//JR.state.getStubToFunctionMap(locked).erase(I);
DOUT << "JIT: Lazily resolving function '" << F->getName()
<< "' In stub ptr = " << Stub << " actual ptr = "
<< ActualPtr << "\n";
Result = TheJIT->getPointerToFunction(F);
}
// Reacquire the lock to erase the stub in the map.
MutexGuard locked(TheJIT->lock);
// We don't need to reuse this stub in the future, as F is now compiled.
JR.state.getFunctionToStubMap(locked).erase(F);
// FIXME: We could rewrite all references to this stub if we knew them.
// What we will do is set the compiled function address to map to the
// same GOT entry as the stub so that later clients may update the GOT
// if they see it still using the stub address.
// Note: this is done so the Resolver doesn't have to manage GOT memory
// Do this without allocating map space if the target isn't using a GOT
if(JR.revGOTMap.find(Stub) != JR.revGOTMap.end())
JR.revGOTMap[Result] = JR.revGOTMap[Stub];
return Result;
}
//===----------------------------------------------------------------------===//
// Function Index Support
// On MacOS we generate an index of currently JIT'd functions so that
// performance tools can determine a symbol name and accurate code range for a
// PC value. Because performance tools are generally asynchronous, the code
// below is written with the hope that it could be interrupted at any time and
// have useful answers. However, we don't go crazy with atomic operations, we
// just do a "reasonable effort".
#ifdef __APPLE__
#define ENABLE_JIT_SYMBOL_TABLE 0
#endif
/// JitSymbolEntry - Each function that is JIT compiled results in one of these
/// being added to an array of symbols. This indicates the name of the function
/// as well as the address range it occupies. This allows the client to map
/// from a PC value to the name of the function.
struct JitSymbolEntry {
const char *FnName; // FnName - a strdup'd string.
void *FnStart;
intptr_t FnSize;
};
struct JitSymbolTable {
/// NextPtr - This forms a linked list of JitSymbolTable entries. This
/// pointer is not used right now, but might be used in the future. Consider
/// it reserved for future use.
JitSymbolTable *NextPtr;
/// Symbols - This is an array of JitSymbolEntry entries. Only the first
/// 'NumSymbols' symbols are valid.
JitSymbolEntry *Symbols;
/// NumSymbols - This indicates the number entries in the Symbols array that
/// are valid.
unsigned NumSymbols;
/// NumAllocated - This indicates the amount of space we have in the Symbols
/// array. This is a private field that should not be read by external tools.
unsigned NumAllocated;
};
#if ENABLE_JIT_SYMBOL_TABLE
JitSymbolTable *__jitSymbolTable;
#endif
static void AddFunctionToSymbolTable(const char *FnName,
void *FnStart, intptr_t FnSize) {
assert(FnName != 0 && FnStart != 0 && "Bad symbol to add");
JitSymbolTable **SymTabPtrPtr = 0;
#if !ENABLE_JIT_SYMBOL_TABLE
return;
#else
SymTabPtrPtr = &__jitSymbolTable;
#endif
// If this is the first entry in the symbol table, add the JitSymbolTable
// index.
if (*SymTabPtrPtr == 0) {
JitSymbolTable *New = new JitSymbolTable();
New->NextPtr = 0;
New->Symbols = 0;
New->NumSymbols = 0;
New->NumAllocated = 0;
*SymTabPtrPtr = New;
}
JitSymbolTable *SymTabPtr = *SymTabPtrPtr;
// If we have space in the table, reallocate the table.
if (SymTabPtr->NumSymbols >= SymTabPtr->NumAllocated) {
// If we don't have space, reallocate the table.
unsigned NewSize = std::max(64U, SymTabPtr->NumAllocated*2);
JitSymbolEntry *NewSymbols = new JitSymbolEntry[NewSize];
JitSymbolEntry *OldSymbols = SymTabPtr->Symbols;
// Copy the old entries over.
memcpy(NewSymbols, OldSymbols,
SymTabPtr->NumSymbols*sizeof(OldSymbols[0]));
// Swap the new symbols in, delete the old ones.
SymTabPtr->Symbols = NewSymbols;
SymTabPtr->NumAllocated = NewSize;
delete [] OldSymbols;
}
// Otherwise, we have enough space, just tack it onto the end of the array.
JitSymbolEntry &Entry = SymTabPtr->Symbols[SymTabPtr->NumSymbols];
Entry.FnName = strdup(FnName);
Entry.FnStart = FnStart;
Entry.FnSize = FnSize;
++SymTabPtr->NumSymbols;
}
static void RemoveFunctionFromSymbolTable(void *FnStart) {
assert(FnStart && "Invalid function pointer");
JitSymbolTable **SymTabPtrPtr = 0;
#if !ENABLE_JIT_SYMBOL_TABLE
return;
#else
SymTabPtrPtr = &__jitSymbolTable;
#endif
JitSymbolTable *SymTabPtr = *SymTabPtrPtr;
JitSymbolEntry *Symbols = SymTabPtr->Symbols;
// Scan the table to find its index. The table is not sorted, so do a linear
// scan.
unsigned Index;
for (Index = 0; Symbols[Index].FnStart != FnStart; ++Index)
assert(Index != SymTabPtr->NumSymbols && "Didn't find function!");
// Once we have an index, we know to nuke this entry, overwrite it with the
// entry at the end of the array, making the last entry redundant.
const char *OldName = Symbols[Index].FnName;
Symbols[Index] = Symbols[SymTabPtr->NumSymbols-1];
free((void*)OldName);
// Drop the number of symbols in the table.
--SymTabPtr->NumSymbols;
// Finally, if we deleted the final symbol, deallocate the table itself.
if (SymTabPtr->NumSymbols != 0)
return;
*SymTabPtrPtr = 0;
delete [] Symbols;
delete SymTabPtr;
}
//===----------------------------------------------------------------------===//
// JITEmitter code.
//
namespace {
/// JITEmitter - The JIT implementation of the MachineCodeEmitter, which is
/// used to output functions to memory for execution.
class JITEmitter : public MachineCodeEmitter {
JITMemoryManager *MemMgr;
// When outputting a function stub in the context of some other function, we
// save BufferBegin/BufferEnd/CurBufferPtr here.
unsigned char *SavedBufferBegin, *SavedBufferEnd, *SavedCurBufferPtr;
/// Relocations - These are the relocations that the function needs, as
/// emitted.
std::vector<MachineRelocation> Relocations;
/// MBBLocations - This vector is a mapping from MBB ID's to their address.
/// It is filled in by the StartMachineBasicBlock callback and queried by
/// the getMachineBasicBlockAddress callback.
std::vector<intptr_t> MBBLocations;
/// ConstantPool - The constant pool for the current function.
///
MachineConstantPool *ConstantPool;
/// ConstantPoolBase - A pointer to the first entry in the constant pool.
///
void *ConstantPoolBase;
/// JumpTable - The jump tables for the current function.
///
MachineJumpTableInfo *JumpTable;
/// JumpTableBase - A pointer to the first entry in the jump table.
///
void *JumpTableBase;
/// Resolver - This contains info about the currently resolved functions.
JITResolver Resolver;
/// DE - The dwarf emitter for the jit.
JITDwarfEmitter *DE;
/// LabelLocations - This vector is a mapping from Label ID's to their
/// address.
std::vector<intptr_t> LabelLocations;
/// MMI - Machine module info for exception informations
MachineModuleInfo* MMI;
// GVSet - a set to keep track of which globals have been seen
std::set<const GlobalVariable*> GVSet;
public:
JITEmitter(JIT &jit, JITMemoryManager *JMM) : Resolver(jit) {
MemMgr = JMM ? JMM : JITMemoryManager::CreateDefaultMemManager();
if (jit.getJITInfo().needsGOT()) {
MemMgr->AllocateGOT();
DOUT << "JIT is managing a GOT\n";
}
if (ExceptionHandling) DE = new JITDwarfEmitter(jit);
}
~JITEmitter() {
delete MemMgr;
if (ExceptionHandling) delete DE;
}
/// classof - Methods for support type inquiry through isa, cast, and
/// dyn_cast:
///
static inline bool classof(const JITEmitter*) { return true; }
static inline bool classof(const MachineCodeEmitter*) { return true; }
JITResolver &getJITResolver() { return Resolver; }
virtual void startFunction(MachineFunction &F);
virtual bool finishFunction(MachineFunction &F);
void emitConstantPool(MachineConstantPool *MCP);
void initJumpTableInfo(MachineJumpTableInfo *MJTI);
void emitJumpTableInfo(MachineJumpTableInfo *MJTI);
virtual void startFunctionStub(const GlobalValue* F, unsigned StubSize,
unsigned Alignment = 1);
virtual void* finishFunctionStub(const GlobalValue *F);
virtual void addRelocation(const MachineRelocation &MR) {
Relocations.push_back(MR);
}
virtual void StartMachineBasicBlock(MachineBasicBlock *MBB) {
if (MBBLocations.size() <= (unsigned)MBB->getNumber())
MBBLocations.resize((MBB->getNumber()+1)*2);
MBBLocations[MBB->getNumber()] = getCurrentPCValue();
}
virtual intptr_t getConstantPoolEntryAddress(unsigned Entry) const;
virtual intptr_t getJumpTableEntryAddress(unsigned Entry) const;
virtual intptr_t getMachineBasicBlockAddress(MachineBasicBlock *MBB) const {
assert(MBBLocations.size() > (unsigned)MBB->getNumber() &&
MBBLocations[MBB->getNumber()] && "MBB not emitted!");
return MBBLocations[MBB->getNumber()];
}
/// deallocateMemForFunction - Deallocate all memory for the specified
/// function body.
void deallocateMemForFunction(Function *F) {
MemMgr->deallocateMemForFunction(F);
}
virtual void emitLabel(uint64_t LabelID) {
if (LabelLocations.size() <= LabelID)
LabelLocations.resize((LabelID+1)*2);
LabelLocations[LabelID] = getCurrentPCValue();
}
virtual intptr_t getLabelAddress(uint64_t LabelID) const {
assert(LabelLocations.size() > (unsigned)LabelID &&
LabelLocations[LabelID] && "Label not emitted!");
return LabelLocations[LabelID];
}
virtual void setModuleInfo(MachineModuleInfo* Info) {
MMI = Info;
if (ExceptionHandling) DE->setModuleInfo(Info);
}
void setMemoryExecutable(void) {
MemMgr->setMemoryExecutable();
}
private:
void *getPointerToGlobal(GlobalValue *GV, void *Reference, bool NoNeedStub);
void *getPointerToGVLazyPtr(GlobalValue *V, void *Reference,
bool NoNeedStub);
unsigned addSizeOfGlobal(const GlobalVariable *GV, unsigned Size);
unsigned addSizeOfGlobalsInConstantVal(const Constant *C, unsigned Size);
unsigned addSizeOfGlobalsInInitializer(const Constant *Init, unsigned Size);
unsigned GetSizeOfGlobalsInBytes(MachineFunction &MF);
};
}
void *JITEmitter::getPointerToGlobal(GlobalValue *V, void *Reference,
bool DoesntNeedStub) {
if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V)) {
/// FIXME: If we straightened things out, this could actually emit the
/// global immediately instead of queuing it for codegen later!
return TheJIT->getOrEmitGlobalVariable(GV);
}
if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V))
return TheJIT->getPointerToGlobal(GA->resolveAliasedGlobal(false));
// If we have already compiled the function, return a pointer to its body.
Function *F = cast<Function>(V);
void *ResultPtr = TheJIT->getPointerToGlobalIfAvailable(F);
if (ResultPtr) return ResultPtr;
if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode()) {
// If this is an external function pointer, we can force the JIT to
// 'compile' it, which really just adds it to the map.
if (DoesntNeedStub)
return TheJIT->getPointerToFunction(F);
return Resolver.getFunctionStub(F);
}
// Okay, the function has not been compiled yet, if the target callback
// mechanism is capable of rewriting the instruction directly, prefer to do
// that instead of emitting a stub.
if (DoesntNeedStub)
return Resolver.AddCallbackAtLocation(F, Reference);
// Otherwise, we have to emit a lazy resolving stub.
return Resolver.getFunctionStub(F);
}
void *JITEmitter::getPointerToGVLazyPtr(GlobalValue *V, void *Reference,
bool DoesntNeedStub) {
// Make sure GV is emitted first.
// FIXME: For now, if the GV is an external function we force the JIT to
// compile it so the lazy pointer will contain the fully resolved address.
void *GVAddress = getPointerToGlobal(V, Reference, true);
return Resolver.getGlobalValueLazyPtr(V, GVAddress);
}
static unsigned GetConstantPoolSizeInBytes(MachineConstantPool *MCP) {
const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
if (Constants.empty()) return 0;
MachineConstantPoolEntry CPE = Constants.back();
unsigned Size = CPE.Offset;
const Type *Ty = CPE.isMachineConstantPoolEntry()
? CPE.Val.MachineCPVal->getType() : CPE.Val.ConstVal->getType();
Size += TheJIT->getTargetData()->getABITypeSize(Ty);
return Size;
}
static unsigned GetJumpTableSizeInBytes(MachineJumpTableInfo *MJTI) {
const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
if (JT.empty()) return 0;
unsigned NumEntries = 0;
for (unsigned i = 0, e = JT.size(); i != e; ++i)
NumEntries += JT[i].MBBs.size();
unsigned EntrySize = MJTI->getEntrySize();
return NumEntries * EntrySize;
}
static uintptr_t RoundUpToAlign(uintptr_t Size, unsigned Alignment) {
if (Alignment == 0) Alignment = 1;
// Since we do not know where the buffer will be allocated, be pessimistic.
return Size + Alignment;
}
/// addSizeOfGlobal - add the size of the global (plus any alignment padding)
/// into the running total Size.
unsigned JITEmitter::addSizeOfGlobal(const GlobalVariable *GV, unsigned Size) {
const Type *ElTy = GV->getType()->getElementType();
size_t GVSize = (size_t)TheJIT->getTargetData()->getABITypeSize(ElTy);
size_t GVAlign =
(size_t)TheJIT->getTargetData()->getPreferredAlignment(GV);
DOUT << "Adding in size " << GVSize << " alignment " << GVAlign;
DEBUG(GV->dump());
// Assume code section ends with worst possible alignment, so first
// variable needs maximal padding.
if (Size==0)
Size = 1;
Size = ((Size+GVAlign-1)/GVAlign)*GVAlign;
Size += GVSize;
return Size;
}
/// addSizeOfGlobalsInConstantVal - find any globals that we haven't seen yet
/// but are referenced from the constant; put them in GVSet and add their
/// size into the running total Size.
unsigned JITEmitter::addSizeOfGlobalsInConstantVal(const Constant *C,
unsigned Size) {
// If its undefined, return the garbage.
if (isa<UndefValue>(C))
return Size;
// If the value is a ConstantExpr
if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
Constant *Op0 = CE->getOperand(0);
switch (CE->getOpcode()) {
case Instruction::GetElementPtr:
case Instruction::Trunc:
case Instruction::ZExt:
case Instruction::SExt:
case Instruction::FPTrunc:
case Instruction::FPExt:
case Instruction::UIToFP:
case Instruction::SIToFP:
case Instruction::FPToUI:
case Instruction::FPToSI:
case Instruction::PtrToInt:
case Instruction::IntToPtr:
case Instruction::BitCast: {
Size = addSizeOfGlobalsInConstantVal(Op0, Size);
break;
}
case Instruction::Add:
case Instruction::Sub:
case Instruction::Mul:
case Instruction::UDiv:
case Instruction::SDiv:
case Instruction::URem:
case Instruction::SRem:
case Instruction::And:
case Instruction::Or:
case Instruction::Xor: {
Size = addSizeOfGlobalsInConstantVal(Op0, Size);
Size = addSizeOfGlobalsInConstantVal(CE->getOperand(1), Size);
break;
}
default: {
cerr << "ConstantExpr not handled: " << *CE << "\n";
abort();
}
}
}
if (C->getType()->getTypeID() == Type::PointerTyID)
if (const GlobalVariable* GV = dyn_cast<GlobalVariable>(C))
if (GVSet.insert(GV).second)
Size = addSizeOfGlobal(GV, Size);
return Size;
}
/// addSizeOfGLobalsInInitializer - handle any globals that we haven't seen yet
/// but are referenced from the given initializer.
unsigned JITEmitter::addSizeOfGlobalsInInitializer(const Constant *Init,
unsigned Size) {
if (!isa<UndefValue>(Init) &&
!isa<ConstantVector>(Init) &&
!isa<ConstantAggregateZero>(Init) &&
!isa<ConstantArray>(Init) &&
!isa<ConstantStruct>(Init) &&
Init->getType()->isFirstClassType())
Size = addSizeOfGlobalsInConstantVal(Init, Size);
return Size;
}
/// GetSizeOfGlobalsInBytes - walk the code for the function, looking for
/// globals; then walk the initializers of those globals looking for more.
/// If their size has not been considered yet, add it into the running total
/// Size.
unsigned JITEmitter::GetSizeOfGlobalsInBytes(MachineFunction &MF) {
unsigned Size = 0;
GVSet.clear();
for (MachineFunction::iterator MBB = MF.begin(), E = MF.end();
MBB != E; ++MBB) {
for (MachineBasicBlock::const_iterator I = MBB->begin(), E = MBB->end();
I != E; ++I) {
const TargetInstrDesc &Desc = I->getDesc();
const MachineInstr &MI = *I;
unsigned NumOps = Desc.getNumOperands();
for (unsigned CurOp = 0; CurOp < NumOps; CurOp++) {
const MachineOperand &MO = MI.getOperand(CurOp);
if (MO.isGlobal()) {
GlobalValue* V = MO.getGlobal();
const GlobalVariable *GV = dyn_cast<const GlobalVariable>(V);
if (!GV)
continue;
// If seen in previous function, it will have an entry here.
if (TheJIT->getPointerToGlobalIfAvailable(GV))
continue;
// If seen earlier in this function, it will have an entry here.
// FIXME: it should be possible to combine these tables, by
// assuming the addresses of the new globals in this module
// start at 0 (or something) and adjusting them after codegen
// complete. Another possibility is to grab a marker bit in GV.
if (GVSet.insert(GV).second)
// A variable as yet unseen. Add in its size.
Size = addSizeOfGlobal(GV, Size);
}
}
}
}
DOUT << "About to look through initializers\n";
// Look for more globals that are referenced only from initializers.
// GVSet.end is computed each time because the set can grow as we go.
for (std::set<const GlobalVariable *>::iterator I = GVSet.begin();
I != GVSet.end(); I++) {
const GlobalVariable* GV = *I;
if (GV->hasInitializer())
Size = addSizeOfGlobalsInInitializer(GV->getInitializer(), Size);
}
return Size;
}
void JITEmitter::startFunction(MachineFunction &F) {
uintptr_t ActualSize = 0;
// Set the memory writable, if it's not already
MemMgr->setMemoryWritable();
if (MemMgr->NeedsExactSize()) {
DOUT << "ExactSize\n";
const TargetInstrInfo* TII = F.getTarget().getInstrInfo();
MachineJumpTableInfo *MJTI = F.getJumpTableInfo();
MachineConstantPool *MCP = F.getConstantPool();
// Ensure the constant pool/jump table info is at least 4-byte aligned.
ActualSize = RoundUpToAlign(ActualSize, 16);
// Add the alignment of the constant pool
ActualSize = RoundUpToAlign(ActualSize,
1 << MCP->getConstantPoolAlignment());
// Add the constant pool size
ActualSize += GetConstantPoolSizeInBytes(MCP);
// Add the aligment of the jump table info
ActualSize = RoundUpToAlign(ActualSize, MJTI->getAlignment());
// Add the jump table size
ActualSize += GetJumpTableSizeInBytes(MJTI);
// Add the alignment for the function
ActualSize = RoundUpToAlign(ActualSize,
std::max(F.getFunction()->getAlignment(), 8U));
// Add the function size
ActualSize += TII->GetFunctionSizeInBytes(F);
DOUT << "ActualSize before globals " << ActualSize << "\n";
// Add the size of the globals that will be allocated after this function.
// These are all the ones referenced from this function that were not
// previously allocated.
ActualSize += GetSizeOfGlobalsInBytes(F);
DOUT << "ActualSize after globals " << ActualSize << "\n";
}
BufferBegin = CurBufferPtr = MemMgr->startFunctionBody(F.getFunction(),
ActualSize);
BufferEnd = BufferBegin+ActualSize;
// Ensure the constant pool/jump table info is at least 4-byte aligned.
emitAlignment(16);
emitConstantPool(F.getConstantPool());
initJumpTableInfo(F.getJumpTableInfo());
// About to start emitting the machine code for the function.
emitAlignment(std::max(F.getFunction()->getAlignment(), 8U));
TheJIT->updateGlobalMapping(F.getFunction(), CurBufferPtr);
MBBLocations.clear();
}
bool JITEmitter::finishFunction(MachineFunction &F) {
if (CurBufferPtr == BufferEnd) {
// FIXME: Allocate more space, then try again.
cerr << "JIT: Ran out of space for generated machine code!\n";
abort();
}
emitJumpTableInfo(F.getJumpTableInfo());
// FnStart is the start of the text, not the start of the constant pool and
// other per-function data.
unsigned char *FnStart =
(unsigned char *)TheJIT->getPointerToGlobalIfAvailable(F.getFunction());
if (!Relocations.empty()) {
NumRelos += Relocations.size();
// Resolve the relocations to concrete pointers.
for (unsigned i = 0, e = Relocations.size(); i != e; ++i) {
MachineRelocation &MR = Relocations[i];
void *ResultPtr;
if (MR.isString()) {
ResultPtr = TheJIT->getPointerToNamedFunction(MR.getString());
// If the target REALLY wants a stub for this function, emit it now.
if (!MR.doesntNeedStub())
ResultPtr = Resolver.getExternalFunctionStub(ResultPtr);
} else if (MR.isGlobalValue()) {
ResultPtr = getPointerToGlobal(MR.getGlobalValue(),
BufferBegin+MR.getMachineCodeOffset(),
MR.doesntNeedStub());
} else if (MR.isGlobalValueLazyPtr()) {
ResultPtr = getPointerToGVLazyPtr(MR.getGlobalValue(),
BufferBegin+MR.getMachineCodeOffset(),
MR.doesntNeedStub());
} else if (MR.isBasicBlock()) {
ResultPtr = (void*)getMachineBasicBlockAddress(MR.getBasicBlock());
} else if (MR.isConstantPoolIndex()) {
ResultPtr=(void*)getConstantPoolEntryAddress(MR.getConstantPoolIndex());
} else {
assert(MR.isJumpTableIndex());
ResultPtr=(void*)getJumpTableEntryAddress(MR.getJumpTableIndex());
}
MR.setResultPointer(ResultPtr);
// if we are managing the GOT and the relocation wants an index,
// give it one
if (MR.isGOTRelative() && MemMgr->isManagingGOT()) {
unsigned idx = Resolver.getGOTIndexForAddr(ResultPtr);
MR.setGOTIndex(idx);
if (((void**)MemMgr->getGOTBase())[idx] != ResultPtr) {
DOUT << "GOT was out of date for " << ResultPtr
<< " pointing at " << ((void**)MemMgr->getGOTBase())[idx]
<< "\n";
((void**)MemMgr->getGOTBase())[idx] = ResultPtr;
}
}
}
TheJIT->getJITInfo().relocate(BufferBegin, &Relocations[0],
Relocations.size(), MemMgr->getGOTBase());
}
unsigned char *FnEnd = CurBufferPtr;
MemMgr->endFunctionBody(F.getFunction(), BufferBegin, FnEnd);
NumBytes += FnEnd-FnStart;
// Update the GOT entry for F to point to the new code.
if (MemMgr->isManagingGOT()) {
unsigned idx = Resolver.getGOTIndexForAddr((void*)BufferBegin);
if (((void**)MemMgr->getGOTBase())[idx] != (void*)BufferBegin) {
DOUT << "GOT was out of date for " << (void*)BufferBegin
<< " pointing at " << ((void**)MemMgr->getGOTBase())[idx] << "\n";
((void**)MemMgr->getGOTBase())[idx] = (void*)BufferBegin;
}
}
// Invalidate the icache if necessary.
sys::Memory::InvalidateInstructionCache(FnStart, FnEnd-FnStart);
// Add it to the JIT symbol table if the host wants it.
AddFunctionToSymbolTable(F.getFunction()->getNameStart(),
FnStart, FnEnd-FnStart);
DOUT << "JIT: Finished CodeGen of [" << (void*)FnStart
<< "] Function: " << F.getFunction()->getName()
<< ": " << (FnEnd-FnStart) << " bytes of text, "
<< Relocations.size() << " relocations\n";
Relocations.clear();
// Mark code region readable and executable if it's not so already.
MemMgr->setMemoryExecutable();
#ifndef NDEBUG
{
DOUT << std::hex;
int i;
unsigned char* q = FnStart;
for (i=1; q!=FnEnd; q++, i++) {
if (i%8==1)
DOUT << "0x" << (long)q << ": ";
DOUT<< (unsigned short)*q << " ";
if (i%8==0)
DOUT<<"\n";
}
DOUT << std::dec;
if (sys::hasDisassembler())
DOUT << "Disassembled code:\n"
<< sys::disassembleBuffer(FnStart, FnEnd-FnStart, (uintptr_t)FnStart);
}
#endif
if (ExceptionHandling) {
uintptr_t ActualSize = 0;
SavedBufferBegin = BufferBegin;
SavedBufferEnd = BufferEnd;
SavedCurBufferPtr = CurBufferPtr;
if (MemMgr->NeedsExactSize()) {
ActualSize = DE->GetDwarfTableSizeInBytes(F, *this, FnStart, FnEnd);
}
BufferBegin = CurBufferPtr = MemMgr->startExceptionTable(F.getFunction(),
ActualSize);
BufferEnd = BufferBegin+ActualSize;
unsigned char* FrameRegister = DE->EmitDwarfTable(F, *this, FnStart, FnEnd);
MemMgr->endExceptionTable(F.getFunction(), BufferBegin, CurBufferPtr,
FrameRegister);
BufferBegin = SavedBufferBegin;
BufferEnd = SavedBufferEnd;
CurBufferPtr = SavedCurBufferPtr;
TheJIT->RegisterTable(FrameRegister);
}
if (MMI)
MMI->EndFunction();
return false;
}
void JITEmitter::emitConstantPool(MachineConstantPool *MCP) {
const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
if (Constants.empty()) return;
MachineConstantPoolEntry CPE = Constants.back();
unsigned Size = CPE.Offset;
const Type *Ty = CPE.isMachineConstantPoolEntry()
? CPE.Val.MachineCPVal->getType() : CPE.Val.ConstVal->getType();
Size += TheJIT->getTargetData()->getABITypeSize(Ty);
unsigned Align = 1 << MCP->getConstantPoolAlignment();
ConstantPoolBase = allocateSpace(Size, Align);
ConstantPool = MCP;
if (ConstantPoolBase == 0) return; // Buffer overflow.
DOUT << "JIT: Emitted constant pool at [" << ConstantPoolBase
<< "] (size: " << Size << ", alignment: " << Align << ")\n";
// Initialize the memory for all of the constant pool entries.
for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
void *CAddr = (char*)ConstantPoolBase+Constants[i].Offset;
if (Constants[i].isMachineConstantPoolEntry()) {
// FIXME: add support to lower machine constant pool values into bytes!
cerr << "Initialize memory with machine specific constant pool entry"
<< " has not been implemented!\n";
abort();
}
TheJIT->InitializeMemory(Constants[i].Val.ConstVal, CAddr);
DOUT << "JIT: CP" << i << " at [" << CAddr << "]\n";
}
}
void JITEmitter::initJumpTableInfo(MachineJumpTableInfo *MJTI) {
const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
if (JT.empty()) return;
unsigned NumEntries = 0;
for (unsigned i = 0, e = JT.size(); i != e; ++i)
NumEntries += JT[i].MBBs.size();
unsigned EntrySize = MJTI->getEntrySize();
// Just allocate space for all the jump tables now. We will fix up the actual
// MBB entries in the tables after we emit the code for each block, since then
// we will know the final locations of the MBBs in memory.
JumpTable = MJTI;
JumpTableBase = allocateSpace(NumEntries * EntrySize, MJTI->getAlignment());
}
void JITEmitter::emitJumpTableInfo(MachineJumpTableInfo *MJTI) {
const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
if (JT.empty() || JumpTableBase == 0) return;
if (TargetMachine::getRelocationModel() == Reloc::PIC_) {
assert(MJTI->getEntrySize() == 4 && "Cross JIT'ing?");
// For each jump table, place the offset from the beginning of the table
// to the target address.
int *SlotPtr = (int*)JumpTableBase;
for (unsigned i = 0, e = JT.size(); i != e; ++i) {
const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
// Store the offset of the basic block for this jump table slot in the
// memory we allocated for the jump table in 'initJumpTableInfo'
intptr_t Base = (intptr_t)SlotPtr;
for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi) {
intptr_t MBBAddr = getMachineBasicBlockAddress(MBBs[mi]);
*SlotPtr++ = TheJIT->getJITInfo().getPICJumpTableEntry(MBBAddr, Base);
}
}
} else {
assert(MJTI->getEntrySize() == sizeof(void*) && "Cross JIT'ing?");
// For each jump table, map each target in the jump table to the address of
// an emitted MachineBasicBlock.
intptr_t *SlotPtr = (intptr_t*)JumpTableBase;
for (unsigned i = 0, e = JT.size(); i != e; ++i) {
const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
// Store the address of the basic block for this jump table slot in the
// memory we allocated for the jump table in 'initJumpTableInfo'
for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi)
*SlotPtr++ = getMachineBasicBlockAddress(MBBs[mi]);
}
}
}
void JITEmitter::startFunctionStub(const GlobalValue* F, unsigned StubSize,
unsigned Alignment) {
SavedBufferBegin = BufferBegin;
SavedBufferEnd = BufferEnd;
SavedCurBufferPtr = CurBufferPtr;
BufferBegin = CurBufferPtr = MemMgr->allocateStub(F, StubSize, Alignment);
BufferEnd = BufferBegin+StubSize+1;
}
void *JITEmitter::finishFunctionStub(const GlobalValue* F) {
NumBytes += getCurrentPCOffset();
// Invalidate the icache if necessary.
sys::Memory::InvalidateInstructionCache(BufferBegin, NumBytes);
std::swap(SavedBufferBegin, BufferBegin);
BufferEnd = SavedBufferEnd;
CurBufferPtr = SavedCurBufferPtr;
return SavedBufferBegin;
}
// getConstantPoolEntryAddress - Return the address of the 'ConstantNum' entry
// in the constant pool that was last emitted with the 'emitConstantPool'
// method.
//
intptr_t JITEmitter::getConstantPoolEntryAddress(unsigned ConstantNum) const {
assert(ConstantNum < ConstantPool->getConstants().size() &&
"Invalid ConstantPoolIndex!");
return (intptr_t)ConstantPoolBase +
ConstantPool->getConstants()[ConstantNum].Offset;
}
// getJumpTableEntryAddress - Return the address of the JumpTable with index
// 'Index' in the jumpp table that was last initialized with 'initJumpTableInfo'
//
intptr_t JITEmitter::getJumpTableEntryAddress(unsigned Index) const {
const std::vector<MachineJumpTableEntry> &JT = JumpTable->getJumpTables();
assert(Index < JT.size() && "Invalid jump table index!");
unsigned Offset = 0;
unsigned EntrySize = JumpTable->getEntrySize();
for (unsigned i = 0; i < Index; ++i)
Offset += JT[i].MBBs.size();
Offset *= EntrySize;
return (intptr_t)((char *)JumpTableBase + Offset);
}
//===----------------------------------------------------------------------===//
// Public interface to this file
//===----------------------------------------------------------------------===//
MachineCodeEmitter *JIT::createEmitter(JIT &jit, JITMemoryManager *JMM) {
return new JITEmitter(jit, JMM);
}
// getPointerToNamedFunction - This function is used as a global wrapper to
// JIT::getPointerToNamedFunction for the purpose of resolving symbols when
// bugpoint is debugging the JIT. In that scenario, we are loading an .so and
// need to resolve function(s) that are being mis-codegenerated, so we need to
// resolve their addresses at runtime, and this is the way to do it.
extern "C" {
void *getPointerToNamedFunction(const char *Name) {
if (Function *F = TheJIT->FindFunctionNamed(Name))
return TheJIT->getPointerToFunction(F);
return TheJIT->getPointerToNamedFunction(Name);
}
}
// getPointerToFunctionOrStub - If the specified function has been
// code-gen'd, return a pointer to the function. If not, compile it, or use
// a stub to implement lazy compilation if available.
//
void *JIT::getPointerToFunctionOrStub(Function *F) {
// If we have already code generated the function, just return the address.
if (void *Addr = getPointerToGlobalIfAvailable(F))
return Addr;
// Get a stub if the target supports it.
assert(isa<JITEmitter>(MCE) && "Unexpected MCE?");
JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
return JE->getJITResolver().getFunctionStub(F);
}
/// freeMachineCodeForFunction - release machine code memory for given Function.
///
void JIT::freeMachineCodeForFunction(Function *F) {
// Delete translation for this from the ExecutionEngine, so it will get
// retranslated next time it is used.
void *OldPtr = updateGlobalMapping(F, 0);
if (OldPtr)
RemoveFunctionFromSymbolTable(OldPtr);
// Free the actual memory for the function body and related stuff.
assert(isa<JITEmitter>(MCE) && "Unexpected MCE?");
cast<JITEmitter>(MCE)->deallocateMemForFunction(F);
}