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llvm-6502/lib/ExecutionEngine/JIT/JITEmitter.cpp
Jeffrey Yasskin df5a7daff9 Add a JITEventListener interface that gets called back when a new function is 
emitted or the machine code for a function is freed.  Chris mentioned that we
may also want a notification when a stub is emitted, but that'll be a future
change.  I intend to use this to tell oprofile where functions are emitted and
what lines correspond to what addresses.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74157 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-25 02:04:04 +00:00

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//===-- 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/JITCodeEmitter.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/GenericValue.h"
#include "llvm/ExecutionEngine/JITEventListener.h"
#include "llvm/ExecutionEngine/JITMemoryManager.h"
#include "llvm/CodeGen/MachineCodeInfo.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/Support/ValueHandle.h"
#include "llvm/System/Disassembler.h"
#include "llvm/System/Memory.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include <algorithm>
#ifndef NDEBUG
#include <iomanip>
#endif
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 {
public:
typedef std::map<AssertingVH<Function>, void*> FunctionToStubMapTy;
typedef std::map<void*, Function*> StubToFunctionMapTy;
typedef std::map<AssertingVH<GlobalValue>, void*> GlobalToIndirectSymMapTy;
private:
/// FunctionToStubMap - Keep track of the stub created for a particular
/// function so that we can reuse them if necessary.
FunctionToStubMapTy FunctionToStubMap;
/// StubToFunctionMap - Keep track of the function that each stub
/// corresponds to.
StubToFunctionMapTy StubToFunctionMap;
/// GlobalToIndirectSymMap - Keep track of the indirect symbol created for a
/// particular GlobalVariable so that we can reuse them if necessary.
GlobalToIndirectSymMapTy GlobalToIndirectSymMap;
public:
FunctionToStubMapTy& getFunctionToStubMap(const MutexGuard& locked) {
assert(locked.holds(TheJIT->lock));
return FunctionToStubMap;
}
StubToFunctionMapTy& getStubToFunctionMap(const MutexGuard& locked) {
assert(locked.holds(TheJIT->lock));
return StubToFunctionMap;
}
GlobalToIndirectSymMapTy& getGlobalToIndirectSymMap(const MutexGuard& locked) {
assert(locked.holds(TheJIT->lock));
return GlobalToIndirectSymMap;
}
};
/// JITResolver - Keep track of, and resolve, call sites for functions that
/// have not yet been compiled.
class JITResolver {
typedef JITResolverState::FunctionToStubMapTy FunctionToStubMapTy;
typedef JITResolverState::StubToFunctionMapTy StubToFunctionMapTy;
typedef JITResolverState::GlobalToIndirectSymMapTy GlobalToIndirectSymMapTy;
/// 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;
/// revGOTMap - 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;
}
/// getFunctionStubIfAvailable - This returns a pointer to a function stub
/// if it has already been created.
void *getFunctionStubIfAvailable(Function *F);
/// getFunctionStub - This returns a pointer to a function stub, creating
/// one on demand as needed. If empty is true, create a function stub
/// pointing at address 0, to be filled in later.
void *getFunctionStub(Function *F);
/// getExternalFunctionStub - Return a stub for the function at the
/// specified address, created lazily on demand.
void *getExternalFunctionStub(void *FnAddr);
/// getGlobalValueIndirectSym - Return an indirect symbol containing the
/// specified GV address.
void *getGlobalValueIndirectSym(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;
}
void getRelocatableGVs(SmallVectorImpl<GlobalValue*> &GVs,
SmallVectorImpl<void*> &Ptrs);
GlobalValue *invalidateStub(void *Stub);
/// 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;
/// getFunctionStubIfAvailable - This returns a pointer to a function stub
/// if it has already been created.
void *JITResolver::getFunctionStubIfAvailable(Function *F) {
MutexGuard locked(TheJIT->lock);
// If we already have a stub for this function, recycle it.
void *&Stub = state.getFunctionToStubMap(locked)[F];
return Stub;
}
/// 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 are JIT'ing non-lazily, in which
// case we must resolve the symbol now.
void *Actual = TheJIT->isLazyCompilationDisabled()
? (void *)0 : (void *)(intptr_t)LazyResolverFn;
// If this is an external declaration, attempt to resolve the address now
// to place in the stub.
if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode()) {
Actual = TheJIT->getPointerToFunction(F);
// If we resolved the symbol to a null address (eg. a weak external)
// don't emit a stub. Return a null pointer to the application. If dlsym
// stubs are enabled, not being able to resolve the address is not
// meaningful.
if (!Actual && !TheJIT->areDlsymStubsEnabled()) return 0;
}
// Codegen a new stub, calling the lazy resolver or the actual address of the
// external function, if it was resolved.
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;
// If we are JIT'ing non-lazily but need to call a function that does not
// exist yet, add it to the JIT's work list so that we can fill in the stub
// address later.
if (!Actual && TheJIT->isLazyCompilationDisabled())
if (!F->isDeclaration() || F->hasNotBeenReadFromBitcode())
TheJIT->addPendingFunction(F);
return Stub;
}
/// getGlobalValueIndirectSym - Return a lazy pointer containing the specified
/// GV address.
void *JITResolver::getGlobalValueIndirectSym(GlobalValue *GV, void *GVAddress) {
MutexGuard locked(TheJIT->lock);
// If we already have a stub for this global variable, recycle it.
void *&IndirectSym = state.getGlobalToIndirectSymMap(locked)[GV];
if (IndirectSym) return IndirectSym;
// Otherwise, codegen a new indirect symbol.
IndirectSym = TheJIT->getJITInfo().emitGlobalValueIndirectSym(GV, GVAddress,
*TheJIT->getCodeEmitter());
DOUT << "JIT: Indirect symbol emitted at [" << IndirectSym << "] for GV '"
<< GV->getName() << "'\n";
return IndirectSym;
}
/// 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 << "JIT: Adding GOT entry " << idx << " for addr [" << addr << "]\n";
}
return idx;
}
void JITResolver::getRelocatableGVs(SmallVectorImpl<GlobalValue*> &GVs,
SmallVectorImpl<void*> &Ptrs) {
MutexGuard locked(TheJIT->lock);
FunctionToStubMapTy &FM = state.getFunctionToStubMap(locked);
GlobalToIndirectSymMapTy &GM = state.getGlobalToIndirectSymMap(locked);
for (FunctionToStubMapTy::iterator i = FM.begin(), e = FM.end(); i != e; ++i){
Function *F = i->first;
if (F->isDeclaration() && F->hasExternalLinkage()) {
GVs.push_back(i->first);
Ptrs.push_back(i->second);
}
}
for (GlobalToIndirectSymMapTy::iterator i = GM.begin(), e = GM.end();
i != e; ++i) {
GVs.push_back(i->first);
Ptrs.push_back(i->second);
}
}
GlobalValue *JITResolver::invalidateStub(void *Stub) {
MutexGuard locked(TheJIT->lock);
FunctionToStubMapTy &FM = state.getFunctionToStubMap(locked);
StubToFunctionMapTy &SM = state.getStubToFunctionMap(locked);
GlobalToIndirectSymMapTy &GM = state.getGlobalToIndirectSymMap(locked);
// Look up the cheap way first, to see if it's a function stub we are
// invalidating. If so, remove it from both the forward and reverse maps.
if (SM.find(Stub) != SM.end()) {
Function *F = SM[Stub];
SM.erase(Stub);
FM.erase(F);
return F;
}
// Otherwise, it might be an indirect symbol stub. Find it and remove it.
for (GlobalToIndirectSymMapTy::iterator i = GM.begin(), e = GM.end();
i != e; ++i) {
if (i->second != Stub)
continue;
GlobalValue *GV = i->first;
GM.erase(i);
return GV;
}
// Lastly, check to see if it's in the ExternalFnToStubMap.
for (std::map<void *, void *>::iterator i = ExternalFnToStubMap.begin(),
e = ExternalFnToStubMap.end(); i != e; ++i) {
if (i->second != Stub)
continue;
ExternalFnToStubMap.erase(i);
break;
}
return 0;
}
/// 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.
StubToFunctionMapTy::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;
}
//===----------------------------------------------------------------------===//
// JITEmitter code.
//
namespace {
/// JITEmitter - The JIT implementation of the MachineCodeEmitter, which is
/// used to output functions to memory for execution.
class JITEmitter : public JITCodeEmitter {
JITMemoryManager *MemMgr;
// When outputting a function stub in the context of some other function, we
// save BufferBegin/BufferEnd/CurBufferPtr here.
uint8_t *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<uintptr_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;
/// ConstPoolAddresses - Addresses of individual constant pool entries.
///
SmallVector<uintptr_t, 8> ConstPoolAddresses;
/// 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<uintptr_t> LabelLocations;
/// MMI - Machine module info for exception informations
MachineModuleInfo* MMI;
// GVSet - a set to keep track of which globals have been seen
SmallPtrSet<const GlobalVariable*, 8> GVSet;
// CurFn - The llvm function being emitted. Only valid during
// finishFunction().
const Function *CurFn;
// CurFnStubUses - For a given Function, a vector of stubs that it
// references. This facilitates the JIT detecting that a stub is no
// longer used, so that it may be deallocated.
DenseMap<const Function *, SmallVector<void*, 1> > CurFnStubUses;
// StubFnRefs - For a given pointer to a stub, a set of Functions which
// reference the stub. When the count of a stub's references drops to zero,
// the stub is unused.
DenseMap<void *, SmallPtrSet<const Function*, 1> > StubFnRefs;
// ExtFnStubs - A map of external function names to stubs which have entries
// in the JITResolver's ExternalFnToStubMap.
StringMap<void *> ExtFnStubs;
public:
JITEmitter(JIT &jit, JITMemoryManager *JMM) : Resolver(jit), CurFn(0) {
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 startGVStub(const GlobalValue* GV, unsigned StubSize,
unsigned Alignment = 1);
virtual void startGVStub(const GlobalValue* GV, void *Buffer,
unsigned StubSize);
virtual void* finishGVStub(const GlobalValue *GV);
/// allocateSpace - Reserves space in the current block if any, or
/// allocate a new one of the given size.
virtual void *allocateSpace(uintptr_t Size, unsigned Alignment);
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();
DOUT << "JIT: Emitting BB" << MBB->getNumber() << " at ["
<< (void*) getCurrentPCValue() << "]\n";
}
virtual uintptr_t getConstantPoolEntryAddress(unsigned Entry) const;
virtual uintptr_t getJumpTableEntryAddress(unsigned Entry) const;
virtual uintptr_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);
/// AddStubToCurrentFunction - Mark the current function being JIT'd as
/// using the stub at the specified address. Allows
/// deallocateMemForFunction to also remove stubs no longer referenced.
void AddStubToCurrentFunction(void *Stub);
/// getExternalFnStubs - Accessor for the JIT to find stubs emitted for
/// MachineRelocations that reference external functions by name.
const StringMap<void*> &getExternalFnStubs() const { return ExtFnStubs; }
virtual void emitLabel(uint64_t LabelID) {
if (LabelLocations.size() <= LabelID)
LabelLocations.resize((LabelID+1)*2);
LabelLocations[LabelID] = getCurrentPCValue();
}
virtual uintptr_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();
}
JITMemoryManager *getMemMgr(void) const { return MemMgr; }
private:
void *getPointerToGlobal(GlobalValue *GV, void *Reference, bool NoNeedStub);
void *getPointerToGVIndirectSym(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))
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;
if (!DoesntNeedStub && !TheJIT->isLazyCompilationDisabled()) {
// Return the function stub if it's already created.
ResultPtr = Resolver.getFunctionStubIfAvailable(F);
if (ResultPtr)
AddStubToCurrentFunction(ResultPtr);
} else {
ResultPtr = TheJIT->getPointerToGlobalIfAvailable(F);
}
if (ResultPtr) return ResultPtr;
// If this is an external function pointer, we can force the JIT to
// 'compile' it, which really just adds it to the map. In dlsym mode,
// external functions are forced through a stub, regardless of reloc type.
if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode() &&
DoesntNeedStub && !TheJIT->areDlsymStubsEnabled())
return TheJIT->getPointerToFunction(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. This uses the lazy resolver, so is not
// legal if lazy compilation is disabled.
if (DoesntNeedStub && !TheJIT->isLazyCompilationDisabled())
return Resolver.AddCallbackAtLocation(F, Reference);
// Otherwise, we have to emit a stub.
void *StubAddr = Resolver.getFunctionStub(F);
// Add the stub to the current function's list of referenced stubs, so we can
// deallocate them if the current function is ever freed. It's possible to
// return null from getFunctionStub in the case of a weak extern that fails
// to resolve.
if (StubAddr)
AddStubToCurrentFunction(StubAddr);
return StubAddr;
}
void *JITEmitter::getPointerToGVIndirectSym(GlobalValue *V, void *Reference,
bool NoNeedStub) {
// Make sure GV is emitted first, and create a stub containing the fully
// resolved address.
void *GVAddress = getPointerToGlobal(V, Reference, true);
void *StubAddr = Resolver.getGlobalValueIndirectSym(V, GVAddress);
// Add the stub to the current function's list of referenced stubs, so we can
// deallocate them if the current function is ever freed.
AddStubToCurrentFunction(StubAddr);
return StubAddr;
}
void JITEmitter::AddStubToCurrentFunction(void *StubAddr) {
if (!TheJIT->areDlsymStubsEnabled())
return;
assert(CurFn && "Stub added to current function, but current function is 0!");
SmallVectorImpl<void*> &StubsUsed = CurFnStubUses[CurFn];
StubsUsed.push_back(StubAddr);
SmallPtrSet<const Function *, 1> &FnRefs = StubFnRefs[StubAddr];
FnRefs.insert(CurFn);
}
static unsigned GetConstantPoolSizeInBytes(MachineConstantPool *MCP,
const TargetData *TD) {
const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
if (Constants.empty()) return 0;
unsigned Size = 0;
for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
MachineConstantPoolEntry CPE = Constants[i];
unsigned AlignMask = CPE.getAlignment() - 1;
Size = (Size + AlignMask) & ~AlignMask;
const Type *Ty = CPE.getType();
Size += TD->getTypeAllocSize(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()->getTypeAllocSize(ElTy);
size_t GVAlign =
(size_t)TheJIT->getTargetData()->getPreferredAlignment(GV);
DOUT << "JIT: 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::FAdd:
case Instruction::Sub:
case Instruction::FSub:
case Instruction::Mul:
case Instruction::FMul:
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))
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))
// A variable as yet unseen. Add in its size.
Size = addSizeOfGlobal(GV, Size);
}
}
}
}
DOUT << "JIT: 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 (SmallPtrSet<const GlobalVariable *, 8>::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) {
DOUT << "JIT: Starting CodeGen of Function "
<< F.getFunction()->getName() << "\n";
uintptr_t ActualSize = 0;
// Set the memory writable, if it's not already
MemMgr->setMemoryWritable();
if (MemMgr->NeedsExactSize()) {
DOUT << "JIT: 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, MCP->getConstantPoolAlignment());
// Add the constant pool size
ActualSize += GetConstantPoolSizeInBytes(MCP, TheJIT->getTargetData());
// 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 << "JIT: 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 << "JIT: 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.
uint8_t *FnStart =
(uint8_t *)TheJIT->getPointerToGlobalIfAvailable(F.getFunction());
// FnEnd is the end of the function's machine code.
uint8_t *FnEnd = CurBufferPtr;
if (!Relocations.empty()) {
CurFn = F.getFunction();
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 = 0;
if (!MR.letTargetResolve()) {
if (MR.isExternalSymbol()) {
ResultPtr = TheJIT->getPointerToNamedFunction(MR.getExternalSymbol(),
false);
DOUT << "JIT: Map \'" << MR.getExternalSymbol() << "\' to ["
<< ResultPtr << "]\n";
// If the target REALLY wants a stub for this function, emit it now.
if (!MR.doesntNeedStub()) {
if (!TheJIT->areDlsymStubsEnabled()) {
ResultPtr = Resolver.getExternalFunctionStub(ResultPtr);
} else {
void *&Stub = ExtFnStubs[MR.getExternalSymbol()];
if (!Stub) {
Stub = Resolver.getExternalFunctionStub((void *)&Stub);
AddStubToCurrentFunction(Stub);
}
ResultPtr = Stub;
}
}
} else if (MR.isGlobalValue()) {
ResultPtr = getPointerToGlobal(MR.getGlobalValue(),
BufferBegin+MR.getMachineCodeOffset(),
MR.doesntNeedStub());
} else if (MR.isIndirectSymbol()) {
ResultPtr = getPointerToGVIndirectSym(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 << "JIT: GOT was out of date for " << ResultPtr
<< " pointing at " << ((void**)MemMgr->getGOTBase())[idx]
<< "\n";
((void**)MemMgr->getGOTBase())[idx] = ResultPtr;
}
}
}
CurFn = 0;
TheJIT->getJITInfo().relocate(BufferBegin, &Relocations[0],
Relocations.size(), MemMgr->getGOTBase());
}
// 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 << "JIT: GOT was out of date for " << (void*)BufferBegin
<< " pointing at " << ((void**)MemMgr->getGOTBase())[idx] << "\n";
((void**)MemMgr->getGOTBase())[idx] = (void*)BufferBegin;
}
}
// CurBufferPtr may have moved beyond FnEnd, due to memory allocation for
// global variables that were referenced in the relocations.
MemMgr->endFunctionBody(F.getFunction(), BufferBegin, CurBufferPtr);
if (CurBufferPtr == BufferEnd) {
// FIXME: Allocate more space, then try again.
cerr << "JIT: Ran out of space for generated machine code!\n";
abort();
}
BufferBegin = CurBufferPtr = 0;
NumBytes += FnEnd-FnStart;
// Invalidate the icache if necessary.
sys::Memory::InvalidateInstructionCache(FnStart, FnEnd-FnStart);
JITEvent_EmittedFunctionDetails Details;
TheJIT->NotifyFunctionEmitted(*F.getFunction(), FnStart, FnEnd-FnStart,
Details);
DOUT << "JIT: Finished CodeGen of [" << (void*)FnStart
<< "] Function: " << F.getFunction()->getName()
<< ": " << (FnEnd-FnStart) << " bytes of text, "
<< Relocations.size() << " relocations\n";
Relocations.clear();
ConstPoolAddresses.clear();
// Mark code region readable and executable if it's not so already.
MemMgr->setMemoryExecutable();
#ifndef NDEBUG
{
if (sys::hasDisassembler()) {
DOUT << "JIT: Disassembled code:\n";
DOUT << sys::disassembleBuffer(FnStart, FnEnd-FnStart, (uintptr_t)FnStart);
} else {
DOUT << "JIT: Binary code:\n";
DOUT << std::hex;
uint8_t* q = FnStart;
for (int i = 0; q < FnEnd; q += 4, ++i) {
if (i == 4)
i = 0;
if (i == 0)
DOUT << "JIT: " << std::setw(8) << std::setfill('0')
<< (long)(q - FnStart) << ": ";
bool Done = false;
for (int j = 3; j >= 0; --j) {
if (q + j >= FnEnd)
Done = true;
else
DOUT << std::setw(2) << std::setfill('0') << (unsigned short)q[j];
}
if (Done)
break;
DOUT << ' ';
if (i == 3)
DOUT << '\n';
}
DOUT << std::dec;
DOUT<< '\n';
}
}
#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;
uint8_t* 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;
}
/// deallocateMemForFunction - Deallocate all memory for the specified
/// function body. Also drop any references the function has to stubs.
void JITEmitter::deallocateMemForFunction(Function *F) {
MemMgr->deallocateMemForFunction(F);
// If the function did not reference any stubs, return.
if (CurFnStubUses.find(F) == CurFnStubUses.end())
return;
// For each referenced stub, erase the reference to this function, and then
// erase the list of referenced stubs.
SmallVectorImpl<void *> &StubList = CurFnStubUses[F];
for (unsigned i = 0, e = StubList.size(); i != e; ++i) {
void *Stub = StubList[i];
// If we already invalidated this stub for this function, continue.
if (StubFnRefs.count(Stub) == 0)
continue;
SmallPtrSet<const Function *, 1> &FnRefs = StubFnRefs[Stub];
FnRefs.erase(F);
// If this function was the last reference to the stub, invalidate the stub
// in the JITResolver. Were there a memory manager deallocateStub routine,
// we could call that at this point too.
if (FnRefs.empty()) {
DOUT << "\nJIT: Invalidated Stub at [" << Stub << "]\n";
StubFnRefs.erase(Stub);
// Invalidate the stub. If it is a GV stub, update the JIT's global
// mapping for that GV to zero, otherwise, search the string map of
// external function names to stubs and remove the entry for this stub.
GlobalValue *GV = Resolver.invalidateStub(Stub);
if (GV) {
TheJIT->updateGlobalMapping(GV, 0);
} else {
for (StringMapIterator<void*> i = ExtFnStubs.begin(),
e = ExtFnStubs.end(); i != e; ++i) {
if (i->second == Stub) {
ExtFnStubs.erase(i);
break;
}
}
}
}
}
CurFnStubUses.erase(F);
}
void* JITEmitter::allocateSpace(uintptr_t Size, unsigned Alignment) {
if (BufferBegin)
return JITCodeEmitter::allocateSpace(Size, Alignment);
// create a new memory block if there is no active one.
// care must be taken so that BufferBegin is invalidated when a
// block is trimmed
BufferBegin = CurBufferPtr = MemMgr->allocateSpace(Size, Alignment);
BufferEnd = BufferBegin+Size;
return CurBufferPtr;
}
void JITEmitter::emitConstantPool(MachineConstantPool *MCP) {
if (TheJIT->getJITInfo().hasCustomConstantPool())
return;
const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
if (Constants.empty()) return;
unsigned Size = GetConstantPoolSizeInBytes(MCP, TheJIT->getTargetData());
unsigned Align = 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.
unsigned Offset = 0;
for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
MachineConstantPoolEntry CPE = Constants[i];
unsigned AlignMask = CPE.getAlignment() - 1;
Offset = (Offset + AlignMask) & ~AlignMask;
uintptr_t CAddr = (uintptr_t)ConstantPoolBase + Offset;
ConstPoolAddresses.push_back(CAddr);
if (CPE.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(CPE.Val.ConstVal, (void*)CAddr);
DOUT << "JIT: CP" << i << " at [0x"
<< std::hex << CAddr << std::dec << "]\n";
const Type *Ty = CPE.Val.ConstVal->getType();
Offset += TheJIT->getTargetData()->getTypeAllocSize(Ty);
}
}
void JITEmitter::initJumpTableInfo(MachineJumpTableInfo *MJTI) {
if (TheJIT->getJITInfo().hasCustomJumpTables())
return;
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) {
if (TheJIT->getJITInfo().hasCustomJumpTables())
return;
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'
uintptr_t Base = (uintptr_t)SlotPtr;
for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi) {
uintptr_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::startGVStub(const GlobalValue* GV, unsigned StubSize,
unsigned Alignment) {
SavedBufferBegin = BufferBegin;
SavedBufferEnd = BufferEnd;
SavedCurBufferPtr = CurBufferPtr;
BufferBegin = CurBufferPtr = MemMgr->allocateStub(GV, StubSize, Alignment);
BufferEnd = BufferBegin+StubSize+1;
}
void JITEmitter::startGVStub(const GlobalValue* GV, void *Buffer,
unsigned StubSize) {
SavedBufferBegin = BufferBegin;
SavedBufferEnd = BufferEnd;
SavedCurBufferPtr = CurBufferPtr;
BufferBegin = CurBufferPtr = (uint8_t *)Buffer;
BufferEnd = BufferBegin+StubSize+1;
}
void *JITEmitter::finishGVStub(const GlobalValue* GV) {
NumBytes += getCurrentPCOffset();
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.
//
uintptr_t JITEmitter::getConstantPoolEntryAddress(unsigned ConstantNum) const {
assert(ConstantNum < ConstantPool->getConstants().size() &&
"Invalid ConstantPoolIndex!");
return ConstPoolAddresses[ConstantNum];
}
// getJumpTableEntryAddress - Return the address of the JumpTable with index
// 'Index' in the jumpp table that was last initialized with 'initJumpTableInfo'
//
uintptr_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 (uintptr_t)((char *)JumpTableBase + Offset);
}
//===----------------------------------------------------------------------===//
// Public interface to this file
//===----------------------------------------------------------------------===//
JITCodeEmitter *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>(JCE) && "Unexpected MCE?");
JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
return JE->getJITResolver().getFunctionStub(F);
}
void JIT::updateFunctionStub(Function *F) {
// Get the empty stub we generated earlier.
assert(isa<JITEmitter>(JCE) && "Unexpected MCE?");
JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
void *Stub = JE->getJITResolver().getFunctionStub(F);
// Tell the target jit info to rewrite the stub at the specified address,
// rather than creating a new one.
void *Addr = getPointerToGlobalIfAvailable(F);
getJITInfo().emitFunctionStubAtAddr(F, Addr, Stub, *getCodeEmitter());
}
/// updateDlsymStubTable - Emit the data necessary to relocate the stubs
/// that were emitted during code generation.
///
void JIT::updateDlsymStubTable() {
assert(isa<JITEmitter>(JCE) && "Unexpected MCE?");
JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
SmallVector<GlobalValue*, 8> GVs;
SmallVector<void*, 8> Ptrs;
const StringMap<void *> &ExtFns = JE->getExternalFnStubs();
JE->getJITResolver().getRelocatableGVs(GVs, Ptrs);
unsigned nStubs = GVs.size() + ExtFns.size();
// If there are no relocatable stubs, return.
if (nStubs == 0)
return;
// If there are no new relocatable stubs, return.
void *CurTable = JE->getMemMgr()->getDlsymTable();
if (CurTable && (*(unsigned *)CurTable == nStubs))
return;
// Calculate the size of the stub info
unsigned offset = 4 + 4 * nStubs + sizeof(intptr_t) * nStubs;
SmallVector<unsigned, 8> Offsets;
for (unsigned i = 0; i != GVs.size(); ++i) {
Offsets.push_back(offset);
offset += GVs[i]->getName().length() + 1;
}
for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end();
i != e; ++i) {
Offsets.push_back(offset);
offset += strlen(i->first()) + 1;
}
// Allocate space for the new "stub", which contains the dlsym table.
JE->startGVStub(0, offset, 4);
// Emit the number of records
JE->emitInt32(nStubs);
// Emit the string offsets
for (unsigned i = 0; i != nStubs; ++i)
JE->emitInt32(Offsets[i]);
// Emit the pointers. Verify that they are at least 2-byte aligned, and set
// the low bit to 0 == GV, 1 == Function, so that the client code doing the
// relocation can write the relocated pointer at the appropriate place in
// the stub.
for (unsigned i = 0; i != GVs.size(); ++i) {
intptr_t Ptr = (intptr_t)Ptrs[i];
assert((Ptr & 1) == 0 && "Stub pointers must be at least 2-byte aligned!");
if (isa<Function>(GVs[i]))
Ptr |= (intptr_t)1;
if (sizeof(Ptr) == 8)
JE->emitInt64(Ptr);
else
JE->emitInt32(Ptr);
}
for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end();
i != e; ++i) {
intptr_t Ptr = (intptr_t)i->second | 1;
if (sizeof(Ptr) == 8)
JE->emitInt64(Ptr);
else
JE->emitInt32(Ptr);
}
// Emit the strings.
for (unsigned i = 0; i != GVs.size(); ++i)
JE->emitString(GVs[i]->getName());
for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end();
i != e; ++i)
JE->emitString(i->first());
// Tell the JIT memory manager where it is. The JIT Memory Manager will
// deallocate space for the old one, if one existed.
JE->getMemMgr()->SetDlsymTable(JE->finishGVStub(0));
}
/// 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)
TheJIT->NotifyFreeingMachineCode(*F, OldPtr);
// Free the actual memory for the function body and related stuff.
assert(isa<JITEmitter>(JCE) && "Unexpected MCE?");
cast<JITEmitter>(JCE)->deallocateMemForFunction(F);
}
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