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llvm-mirror/lib/ExecutionEngine/JIT/JITEmitter.cpp
Daniel Dunbar 8496064116 More migration to raw_ostream, the water has dried up around the iostream hole. 
- Some clients which used DOUT have moved to DEBUG. We are deprecating the
   "magic" DOUT behavior which avoided calling printing functions when the
   statement was disabled. In addition to being unnecessary magic, it had the
   downside of leaving code in -Asserts builds, and of hiding potentially
   unnecessary computations.

llvm-svn: 77019
2009-07-25 00:23:56 +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/ErrorHandling.h"
#include "llvm/Support/MutexGuard.h"
#include "llvm/Support/ValueHandle.h"
#include "llvm/Support/raw_ostream.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");
STATISTIC(NumRetries, "Number of retries with more memory");
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);
}
DEBUG(errs() << "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());
DEBUG(errs() << "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()) {
llvm_report_error("LLVM JIT requested to do lazy compilation of function '"
+ F->getName() + "' when lazy compiles are disabled!");
}
// 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);
DEBUG(errs() << "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;
// When reattempting to JIT a function after running out of space, we store
// the estimated size of the function we're trying to JIT here, so we can
// ask the memory manager for at least this much space. When we
// successfully emit the function, we reset this back to zero.
uintptr_t SizeEstimate;
/// 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;
/// Information about emitted code, which is passed to the
/// JITEventListeners. This is reset in startFunction and used in
/// finishFunction.
JITEvent_EmittedFunctionDetails EmissionDetails;
// 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;
DebugLocTuple PrevDLT;
public:
JITEmitter(JIT &jit, JITMemoryManager *JMM)
: SizeEstimate(0), 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);
/// allocateGlobal - Allocate memory for a global. Unlike allocateSpace,
/// this method does not allocate memory in the current output buffer,
/// because a global may live longer than the current function.
virtual void *allocateGlobal(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()];
}
/// retryWithMoreMemory - Log a retry and deallocate all memory for the
/// given function. Increase the minimum allocation size so that we get
/// more memory next time.
void retryWithMoreMemory(MachineFunction &F);
/// deallocateMemForFunction - Deallocate all memory for the specified
/// function body.
void deallocateMemForFunction(const 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 processDebugLoc(DebugLoc DL);
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);
}
void JITEmitter::processDebugLoc(DebugLoc DL) {
if (!DL.isUnknown()) {
DebugLocTuple CurDLT = EmissionDetails.MF->getDebugLocTuple(DL);
if (CurDLT.CompileUnit != 0 && PrevDLT != CurDLT) {
JITEvent_EmittedFunctionDetails::LineStart NextLine;
NextLine.Address = getCurrentPCValue();
NextLine.Loc = DL;
EmissionDetails.LineStarts.push_back(NextLine);
}
PrevDLT = CurDLT;
}
}
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: {
std::string msg;
raw_string_ostream Msg(msg);
Msg << "ConstantExpr not handled: " << *CE;
llvm_report_error(Msg.str());
}
}
}
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) {
DEBUG(errs() << "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";
} else if (SizeEstimate > 0) {
// SizeEstimate will be non-zero on reallocation attempts.
ActualSize = SizeEstimate;
}
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();
EmissionDetails.MF = &F;
EmissionDetails.LineStarts.clear();
}
bool JITEmitter::finishFunction(MachineFunction &F) {
if (CurBufferPtr == BufferEnd) {
// We must call endFunctionBody before retrying, because
// deallocateMemForFunction requires it.
MemMgr->endFunctionBody(F.getFunction(), BufferBegin, CurBufferPtr);
retryWithMoreMemory(F);
return true;
}
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) {
retryWithMoreMemory(F);
return true;
} else {
// Now that we've succeeded in emitting the function, reset the
// SizeEstimate back down to zero.
SizeEstimate = 0;
}
BufferBegin = CurBufferPtr = 0;
NumBytes += FnEnd-FnStart;
// Invalidate the icache if necessary.
sys::Memory::InvalidateInstructionCache(FnStart, FnEnd-FnStart);
TheJIT->NotifyFunctionEmitted(*F.getFunction(), FnStart, FnEnd-FnStart,
EmissionDetails);
DEBUG(errs() << "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;
}
void JITEmitter::retryWithMoreMemory(MachineFunction &F) {
DOUT << "JIT: Ran out of space for native code. Reattempting.\n";
Relocations.clear(); // Clear the old relocations or we'll reapply them.
ConstPoolAddresses.clear();
++NumRetries;
deallocateMemForFunction(F.getFunction());
// Try again with at least twice as much free space.
SizeEstimate = (uintptr_t)(2 * (BufferEnd - BufferBegin));
}
/// deallocateMemForFunction - Deallocate all memory for the specified
/// function body. Also drop any references the function has to stubs.
void JITEmitter::deallocateMemForFunction(const 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::allocateGlobal(uintptr_t Size, unsigned Alignment) {
// Delegate this call through the memory manager.
return MemMgr->allocateGlobal(Size, Alignment);
}
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!
llvm_report_error("Initialize memory with machine specific constant pool"
"entry has not been implemented!");
}
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().size() + 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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