Nicolas Geoffray
2008-Apr-04 12:50 UTC
[LLVMdev] Being able to know the jitted code-size before emitting
Evan Cheng wrote:> On Apr 1, 2008, at 12:50 AM, Nicolas Geoffray wrote: > > > That's a hack. :-)It is if you think that code emitter should only be used for actually writing somewhere the data. It is not if you find it another useful utility ;-)> Some targets already have ways to compute the exact > size of a function. See ARM::GetFunctionSize() ARM::GetInstSize(). I'd > like to see them standardized (all targets that have JIT support can > accurately calculate the function / instruction sizes) and then you > can make use of that. >OK, I see. However this requires to do this to all targets. In my solution, it works for all targets, is not very intrusive and requires fewer code, hence introduces fewer bugs ;-)> > Suppose you have the size, can't you pass the desired buffer size to > MachineCodeEmitter and have it do the right thing?Sure, that's what I'm doing. The emitter with the SizeEmitter class will give the accurate size to the MachineCodeEmitter. And the MachineCodeEmitter will emit the instructions in the buffer. My solution is surely using things in a way that wasn't intended, but it works fine and for all targets. Is this really a stopper for integrating it? (You can see here my laziness on implementing the GetFunctionSize to every targets :)). Nicolas> It seems like you > can add the functionality to MachineCodeEmitter rather than add a new > class for it. > > Evan > > >> Nicolas >> >>> Thanks, >>> >>> Evan >>> >>> On Mar 30, 2008, at 12:05 PM, Nicolas Geoffray wrote: >>> >>> >>> >>>> Hi everyone, >>>> >>>> vmkit requires to know the size of a jitted method before emitting >>>> the method. This allows to allocate the correct size for the method. >>>> The attached patch creates this functionality when the flag >>>> SizedMemoryCode is on. >>>> >>>> In order to implement this functionality, i had to virtualize some >>>> MachineCodeEmitter functions. >>>> >>>> Is it OK to commit the patch? >>>> >>>> Thanks, >>>> Nicolas >>>> Index: include/llvm/Target/TargetOptions.h >>>> ==================================================================>>>> --- include/llvm/Target/TargetOptions.h (revision 48944) >>>> +++ include/llvm/Target/TargetOptions.h (working copy) >>>> @@ -74,6 +74,10 @@ >>>> /// be emitted. >>>> extern bool ExceptionHandling; >>>> >>>> + /// SizedMemoryCode - This flags indicates that memory for code >>>> is allocated by >>>> + /// an external allocator which requires the size to allocate >>>> + extern bool SizedMemoryCode; >>>> + >>>> /// PerformTailCallOpt - This flag is enabled when -tailcallopt is >>>> specified >>>> /// on the commandline. When the flag is on, the target will >>>> perform tail call >>>> /// optimization (pop the caller's stack) providing it supports it. >>>> Index: include/llvm/CodeGen/SizeEmitter.h >>>> ==================================================================>>>> --- include/llvm/CodeGen/SizeEmitter.h (revision 0) >>>> +++ include/llvm/CodeGen/SizeEmitter.h (revision 0) >>>> @@ -0,0 +1,116 @@ >>>> +//===-- llvm/CodeGen/MachineCodeEmitter.h - Code emission -------*- >>>> C++ -*-===// >>>> +// >>>> +// The LLVM Compiler Infrastructure >>>> +// >>>> +// This file was developed by the LLVM research group and is >>>> distributed under >>>> +// the University of Illinois Open Source License. See LICENSE.TXT >>>> for details. >>>> +// >>>> +// >>>> >>>> >>>> >>>> ---------------------------------------------------------------------->>>> ==// >>>> +// >>>> +// This file defines an abstract interface that is used by the >>>> machine code >>>> +// emission framework to output the code. This allows machine code >>>> emission to >>>> +// be separated from concerns such as resolution of call targets, >>>> and where the >>>> +// machine code will be written (memory or disk, f.e.). >>>> +// >>>> +// >>>> >>>> >>>> >>>> ---------------------------------------------------------------------->>>> ==// >>>> + >>>> +#ifndef LLVM_CODEGEN_SIZEEMITTER_H >>>> +#define LLVM_CODEGEN_SIZEEMITTER_H >>>> + >>>> +#include "llvm/CodeGen/MachineCodeEmitter.h" >>>> +#include "llvm/CodeGen/MachineFunction.h" >>>> + >>>> +namespace llvm { >>>> + /// SizeEmitter - The JIT implementation of the >>>> MachineCodeEmitter, which is >>>> + /// used to output functions to memory for execution. >>>> +class SizeEmitter : public MachineCodeEmitter { >>>> + MachineFunction * Fn; >>>> + void* ConstantPoolBase; >>>> + void* JumpTableBase; >>>> + MachineConstantPool *ConstantPool; >>>> + MachineJumpTableInfo *JumpTable; >>>> + std::vector<intptr_t> LabelLocations; >>>> + MachineCodeEmitter* MCE; >>>> + >>>> +public: >>>> + SizeEmitter(MachineCodeEmitter* mce) { >>>> + CurBufferPtr = 0; >>>> + BufferBegin = 0; >>>> + BufferEnd = (unsigned char*)-1; >>>> + MCE = mce; >>>> + } >>>> + >>>> + SizeEmitter(std::vector<intptr_t> locations) { >>>> + LabelLocations = locations; >>>> + CurBufferPtr = 0; >>>> + BufferBegin = 0; >>>> + BufferEnd = (unsigned char*)-1; >>>> + } >>>> + >>>> + void initConstantPool(MachineConstantPool *MCP); >>>> + >>>> + void initJumpTableInfo(MachineJumpTableInfo *MJTI); >>>> + >>>> + >>>> + virtual void startFunction(MachineFunction &F) { >>>> + CurBufferPtr = 0; >>>> + Fn = &F; >>>> + >>>> + // Ensure the constant pool/jump table info is at least 4-byte >>>> aligned. >>>> + emitAlignment(16); >>>> + >>>> + initConstantPool(F.getConstantPool()); >>>> + initJumpTableInfo(F.getJumpTableInfo()); >>>> + >>>> + ConstantPoolBase = (void*)(((uintptr_t) ConstantPoolBase) + >>>> CurBufferPtr); >>>> + JumpTableBase = (void*)(((uintptr_t) JumpTableBase) + >>>> CurBufferPtr); >>>> + } >>>> + >>>> + virtual bool finishFunction(MachineFunction &F) { >>>> + MCE->setCurrentPtr(CurBufferPtr); >>>> + return false; >>>> + } >>>> + virtual void startFunctionStub(unsigned StubSize, unsigned >>>> Alignment) {} >>>> + virtual void *finishFunctionStub(const Function *F) { return 0; } >>>> + virtual void addRelocation(const llvm::MachineRelocation&) { } >>>> + virtual void emitByte(unsigned char B) { >>>> + CurBufferPtr++; >>>> + } >>>> + virtual void emitWordLE(unsigned W) { >>>> + CurBufferPtr+=4; >>>> + } >>>> + virtual void emitWordBE(unsigned W) { >>>> + CurBufferPtr+=4; >>>> + } >>>> + virtual void emitInt32(int Value) { >>>> + CurBufferPtr += 4; >>>> + } >>>> + virtual void emitInt64(uint64_t Value) { >>>> + CurBufferPtr += 8; >>>> + } >>>> + virtual void emitAt(uintptr_t *Addr, uintptr_t Value) { >>>> + } >>>> + >>>> + >>>> + >>>> + virtual void StartMachineBasicBlock(MachineBasicBlock *MBB) {} >>>> + virtual intptr_t getConstantPoolEntryAddress(unsigned >>>> ConstantNum) const; >>>> + >>>> + virtual intptr_t getJumpTableEntryAddress(unsigned Index) const; >>>> + >>>> + virtual intptr_t getMachineBasicBlockAddress(MachineBasicBlock >>>> *MBB) const { >>>> + assert(0 && "Should not be in getMachineBasicBlockAddress of >>>> SizeEmitter"); >>>> + } >>>> + >>>> + virtual void emitLabel(uint64_t) {} >>>> + virtual intptr_t getLabelAddress(uint64_t LabelID) const { >>>> + assert(LabelLocations.size() > (unsigned)LabelID && >>>> + LabelLocations[LabelID] && "Label not emitted!"); >>>> + return LabelLocations[LabelID]; >>>> + } >>>> + virtual void setModuleInfo(llvm::MachineModuleInfo*) {} >>>> +}; >>>> + >>>> +} // end llvm namespace >>>> + >>>> +#endif >>>> Index: include/llvm/CodeGen/MachineCodeEmitter.h >>>> ==================================================================>>>> --- include/llvm/CodeGen/MachineCodeEmitter.h (revision 48143) >>>> +++ include/llvm/CodeGen/MachineCodeEmitter.h (working copy) >>>> @@ -18,6 +18,7 @@ >>>> #define LLVM_CODEGEN_MACHINECODEEMITTER_H >>>> >>>> #include "llvm/Support/DataTypes.h" >>>> +#include <string> >>>> #include <vector> >>>> >>>> namespace llvm { >>>> @@ -92,7 +93,7 @@ >>>> /// emitByte - This callback is invoked when a byte needs to be >>>> written to the >>>> /// output stream. >>>> /// >>>> - void emitByte(unsigned char B) { >>>> + virtual void emitByte(unsigned char B) { >>>> if (CurBufferPtr != BufferEnd) >>>> *CurBufferPtr++ = B; >>>> } >>>> @@ -100,7 +101,7 @@ >>>> /// emitWordLE - This callback is invoked when a 32-bit word needs >>>> to be >>>> /// written to the output stream in little-endian format. >>>> /// >>>> - void emitWordLE(unsigned W) { >>>> + virtual void emitWordLE(unsigned W) { >>>> if (CurBufferPtr+4 <= BufferEnd) { >>>> *CurBufferPtr++ = (unsigned char)(W >> 0); >>>> *CurBufferPtr++ = (unsigned char)(W >> 8); >>>> @@ -114,7 +115,7 @@ >>>> /// emitWordBE - This callback is invoked when a 32-bit word needs >>>> to be >>>> /// written to the output stream in big-endian format. >>>> /// >>>> - void emitWordBE(unsigned W) { >>>> + virtual void emitWordBE(unsigned W) { >>>> if (CurBufferPtr+4 <= BufferEnd) { >>>> *CurBufferPtr++ = (unsigned char)(W >> 24); >>>> *CurBufferPtr++ = (unsigned char)(W >> 16); >>>> @@ -175,7 +176,7 @@ >>>> } >>>> >>>> /// emitInt32 - Emit a int32 directive. >>>> - void emitInt32(int Value) { >>>> + virtual void emitInt32(int Value) { >>>> if (CurBufferPtr+4 <= BufferEnd) { >>>> *((uint32_t*)CurBufferPtr) = Value; >>>> CurBufferPtr += 4; >>>> @@ -185,7 +186,7 @@ >>>> } >>>> >>>> /// emitInt64 - Emit a int64 directive. >>>> - void emitInt64(uint64_t Value) { >>>> + virtual void emitInt64(uint64_t Value) { >>>> if (CurBufferPtr+8 <= BufferEnd) { >>>> *((uint64_t*)CurBufferPtr) = Value; >>>> CurBufferPtr += 8; >>>> @@ -195,7 +196,7 @@ >>>> } >>>> >>>> /// emitAt - Emit Value in Addr >>>> - void emitAt(uintptr_t *Addr, uintptr_t Value) { >>>> + virtual void emitAt(uintptr_t *Addr, uintptr_t Value) { >>>> if (Addr >= (uintptr_t*)BufferBegin && Addr < >>>> (uintptr_t*)BufferEnd) >>>> (*Addr) = Value; >>>> } >>>> @@ -270,6 +271,11 @@ >>>> /// Specifies the MachineModuleInfo object. This is used for >>>> exception handling >>>> /// purposes. >>>> virtual void setModuleInfo(MachineModuleInfo* Info) = 0; >>>> + >>>> + void setCurrentPtr(unsigned char* Ptr) { >>>> + CurBufferPtr = Ptr; >>>> + } >>>> + >>>> }; >>>> >>>> } // End llvm namespace >>>> Index: lib/CodeGen/LLVMTargetMachine.cpp >>>> ==================================================================>>>> --- lib/CodeGen/LLVMTargetMachine.cpp (revision 48143) >>>> +++ lib/CodeGen/LLVMTargetMachine.cpp (working copy) >>>> @@ -17,6 +17,7 @@ >>>> #include "llvm/Assembly/PrintModulePass.h" >>>> #include "llvm/Analysis/LoopPass.h" >>>> #include "llvm/CodeGen/Passes.h" >>>> +#include "llvm/CodeGen/SizeEmitter.h" >>>> #include "llvm/CodeGen/Collector.h" >>>> #include "llvm/Target/TargetOptions.h" >>>> #include "llvm/Transforms/Scalar.h" >>>> @@ -257,7 +258,13 @@ >>>> >>>> if (addPreEmitPass(PM, Fast) && PrintMachineCode) >>>> PM.add(createMachineFunctionPrinterPass(cerr)); >>>> + >>>> + if (SizedMemoryCode) { >>>> + SizeEmitter * SE = new SizeEmitter(&MCE); >>>> + addSimpleCodeEmitter(PM, Fast, false, *SE); >>>> + } >>>> >>>> + >>>> addCodeEmitter(PM, Fast, PrintEmittedAsm, MCE); >>>> >>>> PM.add(createCollectorMetadataDeleter()); >>>> Index: lib/CodeGen/SizeEmitter.cpp >>>> ==================================================================>>>> --- lib/CodeGen/SizeEmitter.cpp (revision 0) >>>> +++ lib/CodeGen/SizeEmitter.cpp (revision 0) >>>> @@ -0,0 +1,77 @@ >>>> +#include "llvm/CodeGen/SizeEmitter.h" >>>> +#include "llvm/Constant.h" >>>> +#include "llvm/Constants.h" >>>> +#include "llvm/DerivedTypes.h" >>>> +#include "llvm/Module.h" >>>> +#include "llvm/Type.h" >>>> +#include "llvm/CodeGen/MachineCodeEmitter.h" >>>> +#include "llvm/CodeGen/MachineFunction.h" >>>> +#include "llvm/CodeGen/MachineConstantPool.h" >>>> +#include "llvm/CodeGen/MachineJumpTableInfo.h" >>>> +#include "llvm/CodeGen/MachineRelocation.h" >>>> +#include "llvm/ExecutionEngine/GenericValue.h" >>>> +#include "llvm/Target/TargetData.h" >>>> +#include "llvm/Target/TargetJITInfo.h" >>>> +#include "llvm/Target/TargetMachine.h" >>>> +#include "llvm/Target/TargetOptions.h" >>>> +#include "llvm/Support/Debug.h" >>>> +#include "llvm/Support/MutexGuard.h" >>>> +#include "llvm/System/Disassembler.h" >>>> +#include "llvm/ADT/Statistic.h" >>>> +#include "llvm/System/Memory.h" >>>> +#include <algorithm> >>>> +using namespace llvm; >>>> + >>>> + >>>> +void SizeEmitter::initConstantPool(MachineConstantPool *MCP) { >>>> + const std::vector<MachineConstantPoolEntry> &Constants = MCP- >>>> >>>> >>>>> getConstants(); >>>>> >>>>> >>>> + if (Constants.empty()) return; >>>> + >>>> + MachineConstantPoolEntry CPE = Constants.back(); >>>> + unsigned Size = CPE.Offset; >>>> + const Type *Ty = CPE.isMachineConstantPoolEntry() >>>> + ? CPE.Val.MachineCPVal->getType() : CPE.Val.ConstVal- >>>> >>>>> getType(); >>>>> >>>> + Size += Fn->getTarget().getTargetData()->getABITypeSize(Ty); >>>> + ConstantPoolBase = allocateSpace(Size, 1 << MCP- >>>> >>>> >>>>> getConstantPoolAlignment()); >>>>> >>>>> >>>> + ConstantPool = MCP; >>>> +} >>>> + >>>> +void SizeEmitter::initJumpTableInfo(MachineJumpTableInfo *MJTI) { >>>> + const std::vector<MachineJumpTableEntry> &JT = MJTI- >>>> >>>> >>>>> getJumpTables(); >>>>> >>>>> >>>> + if (JT.empty()) return; >>>> + >>>> + unsigned NumEntries = 0; >>>> + for (unsigned i = 0, e = JT.size(); i != e; ++i) >>>> + NumEntries += JT[i].MBBs.size(); >>>> + >>>> + unsigned EntrySize = MJTI->getEntrySize(); >>>> + >>>> + // Just allocate space for all the jump tables now. We will fix >>>> up the actual >>>> + // MBB entries in the tables after we emit the code for each >>>> block, since then >>>> + // we will know the final locations of the MBBs in memory. >>>> + JumpTable = MJTI; >>>> + JumpTableBase = allocateSpace(NumEntries * EntrySize, MJTI- >>>> >>>> >>>>> getAlignment()); >>>>> >>>>> >>>> +} >>>> + >>>> +intptr_t SizeEmitter::getConstantPoolEntryAddress(unsigned >>>> ConstantNum) const { >>>> + assert(ConstantNum < ConstantPool->getConstants().size() && >>>> + "Invalid ConstantPoolIndex!"); >>>> + return (intptr_t)ConstantPoolBase + >>>> + ConstantPool->getConstants()[ConstantNum].Offset; >>>> +} >>>> + >>>> +intptr_t SizeEmitter::getJumpTableEntryAddress(unsigned Index) >>>> const { >>>> + const std::vector<MachineJumpTableEntry> &JT = JumpTable- >>>> >>>> >>>>> getJumpTables(); >>>>> >>>>> >>>> + assert(Index < JT.size() && "Invalid jump table index!"); >>>> + >>>> + unsigned Offset = 0; >>>> + unsigned EntrySize = JumpTable->getEntrySize(); >>>> + >>>> + for (unsigned i = 0; i < Index; ++i) >>>> + Offset += JT[i].MBBs.size(); >>>> + >>>> + Offset *= EntrySize; >>>> + >>>> + return (intptr_t)((char *)JumpTableBase + Offset); >>>> +} >>>> + >>>> Index: lib/Target/TargetMachine.cpp >>>> ==================================================================>>>> --- lib/Target/TargetMachine.cpp (revision 48143) >>>> +++ lib/Target/TargetMachine.cpp (working copy) >>>> @@ -31,6 +31,7 @@ >>>> bool UseSoftFloat; >>>> bool NoZerosInBSS; >>>> bool ExceptionHandling; >>>> + bool SizedMemoryCode; >>>> Reloc::Model RelocationModel; >>>> CodeModel::Model CMModel; >>>> bool PerformTailCallOpt; >>>> Index: lib/ExecutionEngine/JIT/JITEmitter.cpp >>>> ==================================================================>>>> --- lib/ExecutionEngine/JIT/JITEmitter.cpp (revision 48143) >>>> +++ lib/ExecutionEngine/JIT/JITEmitter.cpp (working copy) >>>> @@ -18,12 +18,14 @@ >>>> #include "llvm/Constant.h" >>>> #include "llvm/Module.h" >>>> #include "llvm/Type.h" >>>> +#include "llvm/ADT/DenseMap.h" >>>> #include "llvm/CodeGen/MachineCodeEmitter.h" >>>> #include "llvm/CodeGen/MachineFunction.h" >>>> #include "llvm/CodeGen/MachineConstantPool.h" >>>> #include "llvm/CodeGen/MachineJumpTableInfo.h" >>>> #include "llvm/CodeGen/MachineModuleInfo.h" >>>> #include "llvm/CodeGen/MachineRelocation.h" >>>> +#include "llvm/CodeGen/SizeEmitter.h" >>>> #include "llvm/ExecutionEngine/JITMemoryManager.h" >>>> #include "llvm/Target/TargetData.h" >>>> #include "llvm/Target/TargetJITInfo.h" >>>> @@ -370,6 +376,7 @@ >>>> virtual void startFunction(MachineFunction &F); >>>> virtual bool finishFunction(MachineFunction &F); >>>> >>>> + void initConstantPool(MachineConstantPool *MCP); >>>> void emitConstantPool(MachineConstantPool *MCP); >>>> void initJumpTableInfo(MachineJumpTableInfo *MJTI); >>>> void emitJumpTableInfo(MachineJumpTableInfo *MJTI); >>>> @@ -469,19 +476,47 @@ >>>> >>>> >>>> void JITEmitter::startFunction(MachineFunction &F) { >>>> - uintptr_t ActualSize; >>>> - BufferBegin = CurBufferPtr = MemMgr- >>>> >>>> >>>>> startFunctionBody(F.getFunction(), >>>>> >>>>> >>>> - >>>> ActualSize); >>>> - BufferEnd = BufferBegin+ActualSize; >>>> + MMI->BeginFunction(&F); >>>> >>>> - // Ensure the constant pool/jump table info is at least 4-byte >>>> aligned. >>>> - emitAlignment(16); >>>> + if (SizedMemoryCode) { >>>> + BufferBegin = CurBufferPtr; >>>> + BufferEnd = (unsigned char*) 0xffffffff; >>>> + >>>> + // Ensure the constant pool/jump table info is at least 4-byte >>>> aligned. >>>> + emitAlignment(16); >>>> >>>> - emitConstantPool(F.getConstantPool()); >>>> - initJumpTableInfo(F.getJumpTableInfo()); >>>> + initConstantPool(F.getConstantPool()); >>>> + initJumpTableInfo(F.getJumpTableInfo()); >>>> + >>>> + >>>> + uintptr_t ActualSize = (uintptr_t)CurBufferPtr; >>>> + CurBufferPtr = MemMgr->startFunctionBody(F.getFunction(), >>>> + ActualSize); >>>> + >>>> + ConstantPoolBase = (void*)(((unsigned) ConstantPoolBase) + >>>> CurBufferPtr); >>>> + JumpTableBase = (void*)(((unsigned) JumpTableBase) + >>>> CurBufferPtr); >>>> >>>> - // About to start emitting the machine code for the function. >>>> - emitAlignment(std::max(F.getFunction()->getAlignment(), 8U)); >>>> + emitConstantPool(F.getConstantPool()); >>>> + >>>> + } else { >>>> + uintptr_t ActualSize; >>>> + 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); >>>> + >>>> + initConstantPool(F.getConstantPool()); >>>> + 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(); >>>> @@ -579,12 +614,18 @@ >>>> DOUT << "Disassembled code:\n" >>>> << sys::disassembleBuffer(FnStart, FnEnd-FnStart, >>>> (uintptr_t)FnStart); >>>> #endif >>>> + >>>> if (ExceptionHandling) { >>>> uintptr_t ActualSize; >>>> + if (SizedMemoryCode) { >>>> + SizeEmitter sz(LabelLocations); >>>> + DE->EmitDwarfTable(F, sz, FnStart, FnEnd); >>>> + ActualSize = sz.getCurrentPCValue(); >>>> + } >>>> SavedBufferBegin = BufferBegin; >>>> SavedBufferEnd = BufferEnd; >>>> SavedCurBufferPtr = CurBufferPtr; >>>> - >>>> + >>>> BufferBegin = CurBufferPtr = MemMgr- >>>> >>>> >>>>> startExceptionTable(F.getFunction(), >>>>> >>>>> >>>> ActualSize); >>>> BufferEnd = BufferBegin+ActualSize; >>>> @@ -598,11 +639,10 @@ >>>> TheJIT->RegisterTable(FrameRegister); >>>> } >>>> MMI->EndFunction(); >>>> - >>>> return false; >>>> } >>>> >>>> -void JITEmitter::emitConstantPool(MachineConstantPool *MCP) { >>>> +void JITEmitter::initConstantPool(MachineConstantPool *MCP) { >>>> const std::vector<MachineConstantPoolEntry> &Constants = MCP- >>>> >>>> >>>>> getConstants(); >>>>> >>>>> >>>> if (Constants.empty()) return; >>>> >>>> @@ -611,12 +651,15 @@ >>>> const Type *Ty = CPE.isMachineConstantPoolEntry() >>>> ? CPE.Val.MachineCPVal->getType() : CPE.Val.ConstVal->getType(); >>>> Size += TheJIT->getTargetData()->getABITypeSize(Ty); >>>> - >>>> + >>>> ConstantPoolBase = allocateSpace(Size, 1 << MCP- >>>> >>>> >>>>> getConstantPoolAlignment()); >>>>> >>>>> >>>> ConstantPool = MCP; >>>> +} >>>> >>>> +void JITEmitter::emitConstantPool(MachineConstantPool *MCP) { >>>> if (ConstantPoolBase == 0) return; // Buffer overflow. >>>> >>>> + const std::vector<MachineConstantPoolEntry> &Constants = MCP- >>>> >>>> >>>>> getConstants(); >>>>> >>>>> >>>> // Initialize the memory for all of the constant pool entries. >>>> for (unsigned i = 0, e = Constants.size(); i != e; ++i) { >>>> void *CAddr = (char*)ConstantPoolBase+Constants[i].Offset; >>>> _______________________________________________ >>>> LLVM Developers mailing list >>>> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu >>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >>>> >>>> >>> _______________________________________________ >>> LLVM Developers mailing list >>> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu >>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >>> >>> >> _______________________________________________ >> LLVM Developers mailing list >> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu >> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >> > > _______________________________________________ > LLVM Developers mailing list > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >
Evan Cheng
2008-Apr-04 16:42 UTC
[LLVMdev] Being able to know the jitted code-size before emitting
On Apr 4, 2008, at 5:50 AM, Nicolas Geoffray wrote:> Evan Cheng wrote: >> On Apr 1, 2008, at 12:50 AM, Nicolas Geoffray wrote: >> >> >> That's a hack. :-) > > It is if you think that code emitter should only be used for actually > writing somewhere the data. It is not if you find it another useful > utility ;-)Except it's pretty slow at it. :-)> > >> Some targets already have ways to compute the exact >> size of a function. See ARM::GetFunctionSize() ARM::GetInstSize(). >> I'd >> like to see them standardized (all targets that have JIT support can >> accurately calculate the function / instruction sizes) and then you >> can make use of that. >> > > OK, I see. However this requires to do this to all targets. In my > solution, it works for all targets, is not very intrusive and requires > fewer code, hence introduces fewer bugs ;-)Let's see. ARM has it already. PPC has getNumBytesForInstruction so you only need to add one to compute function size. Also you only need to implement it for targets that support JIT right now, which leaves Alpha and X86. I'm guessing Alpha is using fixed encoding so it should be pretty easy. Or you can just punt it and let the target maintainers worry about it. Really you only need to implement GetFunctionSize for X86 and that's not as horrible as you think it is. For each instruction: 1. Compute how many bytes of prefix. The code is there in X86CodeEmitter except all you need is the size, not the prefixes being emitted. 2. For each instruction format, e.g AddRegFrm, MRMDestReg, it's either only one single byte for opcode or one additional ModR/M byte. Again, all the information is right there. 3. Some memory instructions needs a SIB byte. 4. Process the operands! Some special handling for operands that made up of the memory address. But the logic is all there in emitMemModRMByte. What do you think? Evan> > >> >> Suppose you have the size, can't you pass the desired buffer size to >> MachineCodeEmitter and have it do the right thing? > > Sure, that's what I'm doing. The emitter with the SizeEmitter class > will > give the accurate size to the MachineCodeEmitter. And the > MachineCodeEmitter will emit the instructions in the buffer. > > My solution is surely using things in a way that wasn't intended, > but it > works fine and for all targets. Is this really a stopper for > integrating > it? (You can see here my laziness on implementing the > GetFunctionSize to > every targets :)). > > Nicolas > >> It seems like you >> can add the functionality to MachineCodeEmitter rather than add a new >> class for it. >> >> Evan >> >> >>> Nicolas >>> >>>> Thanks, >>>> >>>> Evan >>>> >>>> On Mar 30, 2008, at 12:05 PM, Nicolas Geoffray wrote: >>>> >>>> >>>> >>>>> Hi everyone, >>>>> >>>>> vmkit requires to know the size of a jitted method before emitting >>>>> the method. This allows to allocate the correct size for the >>>>> method. >>>>> The attached patch creates this functionality when the flag >>>>> SizedMemoryCode is on. >>>>> >>>>> In order to implement this functionality, i had to virtualize some >>>>> MachineCodeEmitter functions. >>>>> >>>>> Is it OK to commit the patch? >>>>> >>>>> Thanks, >>>>> Nicolas >>>>> Index: include/llvm/Target/TargetOptions.h >>>>> = >>>>> =================================================================>>>>> --- include/llvm/Target/TargetOptions.h (revision 48944) >>>>> +++ include/llvm/Target/TargetOptions.h (working copy) >>>>> @@ -74,6 +74,10 @@ >>>>> /// be emitted. >>>>> extern bool ExceptionHandling; >>>>> >>>>> + /// SizedMemoryCode - This flags indicates that memory for code >>>>> is allocated by >>>>> + /// an external allocator which requires the size to allocate >>>>> + extern bool SizedMemoryCode; >>>>> + >>>>> /// PerformTailCallOpt - This flag is enabled when -tailcallopt is >>>>> specified >>>>> /// on the commandline. When the flag is on, the target will >>>>> perform tail call >>>>> /// optimization (pop the caller's stack) providing it supports >>>>> it. >>>>> Index: include/llvm/CodeGen/SizeEmitter.h >>>>> = >>>>> =================================================================>>>>> --- include/llvm/CodeGen/SizeEmitter.h (revision 0) >>>>> +++ include/llvm/CodeGen/SizeEmitter.h (revision 0) >>>>> @@ -0,0 +1,116 @@ >>>>> +//===-- llvm/CodeGen/MachineCodeEmitter.h - Code emission >>>>> -------*- >>>>> C++ -*-===// >>>>> +// >>>>> +// The LLVM Compiler Infrastructure >>>>> +// >>>>> +// This file was developed by the LLVM research group and is >>>>> distributed under >>>>> +// the University of Illinois Open Source License. See >>>>> LICENSE.TXT >>>>> for details. >>>>> +// >>>>> +// >>>>> >>>>> >>>>> >>>>> ---------------------------------------------------------------------->>>>> ==// >>>>> +// >>>>> +// This file defines an abstract interface that is used by the >>>>> machine code >>>>> +// emission framework to output the code. This allows machine >>>>> code >>>>> emission to >>>>> +// be separated from concerns such as resolution of call targets, >>>>> and where the >>>>> +// machine code will be written (memory or disk, f.e.). >>>>> +// >>>>> +// >>>>> >>>>> >>>>> >>>>> ---------------------------------------------------------------------->>>>> ==// >>>>> + >>>>> +#ifndef LLVM_CODEGEN_SIZEEMITTER_H >>>>> +#define LLVM_CODEGEN_SIZEEMITTER_H >>>>> + >>>>> +#include "llvm/CodeGen/MachineCodeEmitter.h" >>>>> +#include "llvm/CodeGen/MachineFunction.h" >>>>> + >>>>> +namespace llvm { >>>>> + /// SizeEmitter - The JIT implementation of the >>>>> MachineCodeEmitter, which is >>>>> + /// used to output functions to memory for execution. >>>>> +class SizeEmitter : public MachineCodeEmitter { >>>>> + MachineFunction * Fn; >>>>> + void* ConstantPoolBase; >>>>> + void* JumpTableBase; >>>>> + MachineConstantPool *ConstantPool; >>>>> + MachineJumpTableInfo *JumpTable; >>>>> + std::vector<intptr_t> LabelLocations; >>>>> + MachineCodeEmitter* MCE; >>>>> + >>>>> +public: >>>>> + SizeEmitter(MachineCodeEmitter* mce) { >>>>> + CurBufferPtr = 0; >>>>> + BufferBegin = 0; >>>>> + BufferEnd = (unsigned char*)-1; >>>>> + MCE = mce; >>>>> + } >>>>> + >>>>> + SizeEmitter(std::vector<intptr_t> locations) { >>>>> + LabelLocations = locations; >>>>> + CurBufferPtr = 0; >>>>> + BufferBegin = 0; >>>>> + BufferEnd = (unsigned char*)-1; >>>>> + } >>>>> + >>>>> + void initConstantPool(MachineConstantPool *MCP); >>>>> + >>>>> + void initJumpTableInfo(MachineJumpTableInfo *MJTI); >>>>> + >>>>> + >>>>> + virtual void startFunction(MachineFunction &F) { >>>>> + CurBufferPtr = 0; >>>>> + Fn = &F; >>>>> + >>>>> + // Ensure the constant pool/jump table info is at least 4- >>>>> byte >>>>> aligned. >>>>> + emitAlignment(16); >>>>> + >>>>> + initConstantPool(F.getConstantPool()); >>>>> + initJumpTableInfo(F.getJumpTableInfo()); >>>>> + >>>>> + ConstantPoolBase = (void*)(((uintptr_t) ConstantPoolBase) + >>>>> CurBufferPtr); >>>>> + JumpTableBase = (void*)(((uintptr_t) JumpTableBase) + >>>>> CurBufferPtr); >>>>> + } >>>>> + >>>>> + virtual bool finishFunction(MachineFunction &F) { >>>>> + MCE->setCurrentPtr(CurBufferPtr); >>>>> + return false; >>>>> + } >>>>> + virtual void startFunctionStub(unsigned StubSize, unsigned >>>>> Alignment) {} >>>>> + virtual void *finishFunctionStub(const Function *F) { return >>>>> 0; } >>>>> + virtual void addRelocation(const llvm::MachineRelocation&) { } >>>>> + virtual void emitByte(unsigned char B) { >>>>> + CurBufferPtr++; >>>>> + } >>>>> + virtual void emitWordLE(unsigned W) { >>>>> + CurBufferPtr+=4; >>>>> + } >>>>> + virtual void emitWordBE(unsigned W) { >>>>> + CurBufferPtr+=4; >>>>> + } >>>>> + virtual void emitInt32(int Value) { >>>>> + CurBufferPtr += 4; >>>>> + } >>>>> + virtual void emitInt64(uint64_t Value) { >>>>> + CurBufferPtr += 8; >>>>> + } >>>>> + virtual void emitAt(uintptr_t *Addr, uintptr_t Value) { >>>>> + } >>>>> + >>>>> + >>>>> + >>>>> + virtual void StartMachineBasicBlock(MachineBasicBlock *MBB) {} >>>>> + virtual intptr_t getConstantPoolEntryAddress(unsigned >>>>> ConstantNum) const; >>>>> + >>>>> + virtual intptr_t getJumpTableEntryAddress(unsigned Index) >>>>> const; >>>>> + >>>>> + virtual intptr_t getMachineBasicBlockAddress(MachineBasicBlock >>>>> *MBB) const { >>>>> + assert(0 && "Should not be in getMachineBasicBlockAddress of >>>>> SizeEmitter"); >>>>> + } >>>>> + >>>>> + virtual void emitLabel(uint64_t) {} >>>>> + virtual intptr_t getLabelAddress(uint64_t LabelID) const { >>>>> + assert(LabelLocations.size() > (unsigned)LabelID && >>>>> + LabelLocations[LabelID] && "Label not emitted!"); >>>>> + return LabelLocations[LabelID]; >>>>> + } >>>>> + virtual void setModuleInfo(llvm::MachineModuleInfo*) {} >>>>> +}; >>>>> + >>>>> +} // end llvm namespace >>>>> + >>>>> +#endif >>>>> Index: include/llvm/CodeGen/MachineCodeEmitter.h >>>>> = >>>>> =================================================================>>>>> --- include/llvm/CodeGen/MachineCodeEmitter.h (revision 48143) >>>>> +++ include/llvm/CodeGen/MachineCodeEmitter.h (working copy) >>>>> @@ -18,6 +18,7 @@ >>>>> #define LLVM_CODEGEN_MACHINECODEEMITTER_H >>>>> >>>>> #include "llvm/Support/DataTypes.h" >>>>> +#include <string> >>>>> #include <vector> >>>>> >>>>> namespace llvm { >>>>> @@ -92,7 +93,7 @@ >>>>> /// emitByte - This callback is invoked when a byte needs to be >>>>> written to the >>>>> /// output stream. >>>>> /// >>>>> - void emitByte(unsigned char B) { >>>>> + virtual void emitByte(unsigned char B) { >>>>> if (CurBufferPtr != BufferEnd) >>>>> *CurBufferPtr++ = B; >>>>> } >>>>> @@ -100,7 +101,7 @@ >>>>> /// emitWordLE - This callback is invoked when a 32-bit word needs >>>>> to be >>>>> /// written to the output stream in little-endian format. >>>>> /// >>>>> - void emitWordLE(unsigned W) { >>>>> + virtual void emitWordLE(unsigned W) { >>>>> if (CurBufferPtr+4 <= BufferEnd) { >>>>> *CurBufferPtr++ = (unsigned char)(W >> 0); >>>>> *CurBufferPtr++ = (unsigned char)(W >> 8); >>>>> @@ -114,7 +115,7 @@ >>>>> /// emitWordBE - This callback is invoked when a 32-bit word needs >>>>> to be >>>>> /// written to the output stream in big-endian format. >>>>> /// >>>>> - void emitWordBE(unsigned W) { >>>>> + virtual void emitWordBE(unsigned W) { >>>>> if (CurBufferPtr+4 <= BufferEnd) { >>>>> *CurBufferPtr++ = (unsigned char)(W >> 24); >>>>> *CurBufferPtr++ = (unsigned char)(W >> 16); >>>>> @@ -175,7 +176,7 @@ >>>>> } >>>>> >>>>> /// emitInt32 - Emit a int32 directive. >>>>> - void emitInt32(int Value) { >>>>> + virtual void emitInt32(int Value) { >>>>> if (CurBufferPtr+4 <= BufferEnd) { >>>>> *((uint32_t*)CurBufferPtr) = Value; >>>>> CurBufferPtr += 4; >>>>> @@ -185,7 +186,7 @@ >>>>> } >>>>> >>>>> /// emitInt64 - Emit a int64 directive. >>>>> - void emitInt64(uint64_t Value) { >>>>> + virtual void emitInt64(uint64_t Value) { >>>>> if (CurBufferPtr+8 <= BufferEnd) { >>>>> *((uint64_t*)CurBufferPtr) = Value; >>>>> CurBufferPtr += 8; >>>>> @@ -195,7 +196,7 @@ >>>>> } >>>>> >>>>> /// emitAt - Emit Value in Addr >>>>> - void emitAt(uintptr_t *Addr, uintptr_t Value) { >>>>> + virtual void emitAt(uintptr_t *Addr, uintptr_t Value) { >>>>> if (Addr >= (uintptr_t*)BufferBegin && Addr < >>>>> (uintptr_t*)BufferEnd) >>>>> (*Addr) = Value; >>>>> } >>>>> @@ -270,6 +271,11 @@ >>>>> /// Specifies the MachineModuleInfo object. This is used for >>>>> exception handling >>>>> /// purposes. >>>>> virtual void setModuleInfo(MachineModuleInfo* Info) = 0; >>>>> + >>>>> + void setCurrentPtr(unsigned char* Ptr) { >>>>> + CurBufferPtr = Ptr; >>>>> + } >>>>> + >>>>> }; >>>>> >>>>> } // End llvm namespace >>>>> Index: lib/CodeGen/LLVMTargetMachine.cpp >>>>> = >>>>> =================================================================>>>>> --- lib/CodeGen/LLVMTargetMachine.cpp (revision 48143) >>>>> +++ lib/CodeGen/LLVMTargetMachine.cpp (working copy) >>>>> @@ -17,6 +17,7 @@ >>>>> #include "llvm/Assembly/PrintModulePass.h" >>>>> #include "llvm/Analysis/LoopPass.h" >>>>> #include "llvm/CodeGen/Passes.h" >>>>> +#include "llvm/CodeGen/SizeEmitter.h" >>>>> #include "llvm/CodeGen/Collector.h" >>>>> #include "llvm/Target/TargetOptions.h" >>>>> #include "llvm/Transforms/Scalar.h" >>>>> @@ -257,7 +258,13 @@ >>>>> >>>>> if (addPreEmitPass(PM, Fast) && PrintMachineCode) >>>>> PM.add(createMachineFunctionPrinterPass(cerr)); >>>>> + >>>>> + if (SizedMemoryCode) { >>>>> + SizeEmitter * SE = new SizeEmitter(&MCE); >>>>> + addSimpleCodeEmitter(PM, Fast, false, *SE); >>>>> + } >>>>> >>>>> + >>>>> addCodeEmitter(PM, Fast, PrintEmittedAsm, MCE); >>>>> >>>>> PM.add(createCollectorMetadataDeleter()); >>>>> Index: lib/CodeGen/SizeEmitter.cpp >>>>> = >>>>> =================================================================>>>>> --- lib/CodeGen/SizeEmitter.cpp (revision 0) >>>>> +++ lib/CodeGen/SizeEmitter.cpp (revision 0) >>>>> @@ -0,0 +1,77 @@ >>>>> +#include "llvm/CodeGen/SizeEmitter.h" >>>>> +#include "llvm/Constant.h" >>>>> +#include "llvm/Constants.h" >>>>> +#include "llvm/DerivedTypes.h" >>>>> +#include "llvm/Module.h" >>>>> +#include "llvm/Type.h" >>>>> +#include "llvm/CodeGen/MachineCodeEmitter.h" >>>>> +#include "llvm/CodeGen/MachineFunction.h" >>>>> +#include "llvm/CodeGen/MachineConstantPool.h" >>>>> +#include "llvm/CodeGen/MachineJumpTableInfo.h" >>>>> +#include "llvm/CodeGen/MachineRelocation.h" >>>>> +#include "llvm/ExecutionEngine/GenericValue.h" >>>>> +#include "llvm/Target/TargetData.h" >>>>> +#include "llvm/Target/TargetJITInfo.h" >>>>> +#include "llvm/Target/TargetMachine.h" >>>>> +#include "llvm/Target/TargetOptions.h" >>>>> +#include "llvm/Support/Debug.h" >>>>> +#include "llvm/Support/MutexGuard.h" >>>>> +#include "llvm/System/Disassembler.h" >>>>> +#include "llvm/ADT/Statistic.h" >>>>> +#include "llvm/System/Memory.h" >>>>> +#include <algorithm> >>>>> +using namespace llvm; >>>>> + >>>>> + >>>>> +void SizeEmitter::initConstantPool(MachineConstantPool *MCP) { >>>>> + const std::vector<MachineConstantPoolEntry> &Constants = MCP- >>>>> >>>>> >>>>>> getConstants(); >>>>>> >>>>>> >>>>> + if (Constants.empty()) return; >>>>> + >>>>> + MachineConstantPoolEntry CPE = Constants.back(); >>>>> + unsigned Size = CPE.Offset; >>>>> + const Type *Ty = CPE.isMachineConstantPoolEntry() >>>>> + ? CPE.Val.MachineCPVal->getType() : CPE.Val.ConstVal- >>>>> >>>>>> getType(); >>>>>> >>>>> + Size += Fn->getTarget().getTargetData()->getABITypeSize(Ty); >>>>> + ConstantPoolBase = allocateSpace(Size, 1 << MCP- >>>>> >>>>> >>>>>> getConstantPoolAlignment()); >>>>>> >>>>>> >>>>> + ConstantPool = MCP; >>>>> +} >>>>> + >>>>> +void SizeEmitter::initJumpTableInfo(MachineJumpTableInfo *MJTI) { >>>>> + const std::vector<MachineJumpTableEntry> &JT = MJTI- >>>>> >>>>> >>>>>> getJumpTables(); >>>>>> >>>>>> >>>>> + if (JT.empty()) return; >>>>> + >>>>> + unsigned NumEntries = 0; >>>>> + for (unsigned i = 0, e = JT.size(); i != e; ++i) >>>>> + NumEntries += JT[i].MBBs.size(); >>>>> + >>>>> + unsigned EntrySize = MJTI->getEntrySize(); >>>>> + >>>>> + // Just allocate space for all the jump tables now. We will >>>>> fix >>>>> up the actual >>>>> + // MBB entries in the tables after we emit the code for each >>>>> block, since then >>>>> + // we will know the final locations of the MBBs in memory. >>>>> + JumpTable = MJTI; >>>>> + JumpTableBase = allocateSpace(NumEntries * EntrySize, MJTI- >>>>> >>>>> >>>>>> getAlignment()); >>>>>> >>>>>> >>>>> +} >>>>> + >>>>> +intptr_t SizeEmitter::getConstantPoolEntryAddress(unsigned >>>>> ConstantNum) const { >>>>> + assert(ConstantNum < ConstantPool->getConstants().size() && >>>>> + "Invalid ConstantPoolIndex!"); >>>>> + return (intptr_t)ConstantPoolBase + >>>>> + ConstantPool->getConstants()[ConstantNum].Offset; >>>>> +} >>>>> + >>>>> +intptr_t SizeEmitter::getJumpTableEntryAddress(unsigned Index) >>>>> const { >>>>> + const std::vector<MachineJumpTableEntry> &JT = JumpTable- >>>>> >>>>> >>>>>> getJumpTables(); >>>>>> >>>>>> >>>>> + assert(Index < JT.size() && "Invalid jump table index!"); >>>>> + >>>>> + unsigned Offset = 0; >>>>> + unsigned EntrySize = JumpTable->getEntrySize(); >>>>> + >>>>> + for (unsigned i = 0; i < Index; ++i) >>>>> + Offset += JT[i].MBBs.size(); >>>>> + >>>>> + Offset *= EntrySize; >>>>> + >>>>> + return (intptr_t)((char *)JumpTableBase + Offset); >>>>> +} >>>>> + >>>>> Index: lib/Target/TargetMachine.cpp >>>>> = >>>>> =================================================================>>>>> --- lib/Target/TargetMachine.cpp (revision 48143) >>>>> +++ lib/Target/TargetMachine.cpp (working copy) >>>>> @@ -31,6 +31,7 @@ >>>>> bool UseSoftFloat; >>>>> bool NoZerosInBSS; >>>>> bool ExceptionHandling; >>>>> + bool SizedMemoryCode; >>>>> Reloc::Model RelocationModel; >>>>> CodeModel::Model CMModel; >>>>> bool PerformTailCallOpt; >>>>> Index: lib/ExecutionEngine/JIT/JITEmitter.cpp >>>>> = >>>>> =================================================================>>>>> --- lib/ExecutionEngine/JIT/JITEmitter.cpp (revision 48143) >>>>> +++ lib/ExecutionEngine/JIT/JITEmitter.cpp (working copy) >>>>> @@ -18,12 +18,14 @@ >>>>> #include "llvm/Constant.h" >>>>> #include "llvm/Module.h" >>>>> #include "llvm/Type.h" >>>>> +#include "llvm/ADT/DenseMap.h" >>>>> #include "llvm/CodeGen/MachineCodeEmitter.h" >>>>> #include "llvm/CodeGen/MachineFunction.h" >>>>> #include "llvm/CodeGen/MachineConstantPool.h" >>>>> #include "llvm/CodeGen/MachineJumpTableInfo.h" >>>>> #include "llvm/CodeGen/MachineModuleInfo.h" >>>>> #include "llvm/CodeGen/MachineRelocation.h" >>>>> +#include "llvm/CodeGen/SizeEmitter.h" >>>>> #include "llvm/ExecutionEngine/JITMemoryManager.h" >>>>> #include "llvm/Target/TargetData.h" >>>>> #include "llvm/Target/TargetJITInfo.h" >>>>> @@ -370,6 +376,7 @@ >>>>> virtual void startFunction(MachineFunction &F); >>>>> virtual bool finishFunction(MachineFunction &F); >>>>> >>>>> + void initConstantPool(MachineConstantPool *MCP); >>>>> void emitConstantPool(MachineConstantPool *MCP); >>>>> void initJumpTableInfo(MachineJumpTableInfo *MJTI); >>>>> void emitJumpTableInfo(MachineJumpTableInfo *MJTI); >>>>> @@ -469,19 +476,47 @@ >>>>> >>>>> >>>>> void JITEmitter::startFunction(MachineFunction &F) { >>>>> - uintptr_t ActualSize; >>>>> - BufferBegin = CurBufferPtr = MemMgr- >>>>> >>>>> >>>>>> startFunctionBody(F.getFunction(), >>>>>> >>>>>> >>>>> - >>>>> ActualSize); >>>>> - BufferEnd = BufferBegin+ActualSize; >>>>> + MMI->BeginFunction(&F); >>>>> >>>>> - // Ensure the constant pool/jump table info is at least 4-byte >>>>> aligned. >>>>> - emitAlignment(16); >>>>> + if (SizedMemoryCode) { >>>>> + BufferBegin = CurBufferPtr; >>>>> + BufferEnd = (unsigned char*) 0xffffffff; >>>>> + >>>>> + // Ensure the constant pool/jump table info is at least 4- >>>>> byte >>>>> aligned. >>>>> + emitAlignment(16); >>>>> >>>>> - emitConstantPool(F.getConstantPool()); >>>>> - initJumpTableInfo(F.getJumpTableInfo()); >>>>> + initConstantPool(F.getConstantPool()); >>>>> + initJumpTableInfo(F.getJumpTableInfo()); >>>>> + >>>>> + >>>>> + uintptr_t ActualSize = (uintptr_t)CurBufferPtr; >>>>> + CurBufferPtr = MemMgr->startFunctionBody(F.getFunction(), >>>>> + ActualSize); >>>>> + >>>>> + ConstantPoolBase = (void*)(((unsigned) ConstantPoolBase) + >>>>> CurBufferPtr); >>>>> + JumpTableBase = (void*)(((unsigned) JumpTableBase) + >>>>> CurBufferPtr); >>>>> >>>>> - // About to start emitting the machine code for the function. >>>>> - emitAlignment(std::max(F.getFunction()->getAlignment(), 8U)); >>>>> + emitConstantPool(F.getConstantPool()); >>>>> + >>>>> + } else { >>>>> + uintptr_t ActualSize; >>>>> + 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); >>>>> + >>>>> + initConstantPool(F.getConstantPool()); >>>>> + 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(); >>>>> @@ -579,12 +614,18 @@ >>>>> DOUT << "Disassembled code:\n" >>>>> << sys::disassembleBuffer(FnStart, FnEnd-FnStart, >>>>> (uintptr_t)FnStart); >>>>> #endif >>>>> + >>>>> if (ExceptionHandling) { >>>>> uintptr_t ActualSize; >>>>> + if (SizedMemoryCode) { >>>>> + SizeEmitter sz(LabelLocations); >>>>> + DE->EmitDwarfTable(F, sz, FnStart, FnEnd); >>>>> + ActualSize = sz.getCurrentPCValue(); >>>>> + } >>>>> SavedBufferBegin = BufferBegin; >>>>> SavedBufferEnd = BufferEnd; >>>>> SavedCurBufferPtr = CurBufferPtr; >>>>> - >>>>> + >>>>> BufferBegin = CurBufferPtr = MemMgr- >>>>> >>>>> >>>>>> startExceptionTable(F.getFunction(), >>>>>> >>>>>> >>>>> ActualSize); >>>>> BufferEnd = BufferBegin+ActualSize; >>>>> @@ -598,11 +639,10 @@ >>>>> TheJIT->RegisterTable(FrameRegister); >>>>> } >>>>> MMI->EndFunction(); >>>>> - >>>>> return false; >>>>> } >>>>> >>>>> -void JITEmitter::emitConstantPool(MachineConstantPool *MCP) { >>>>> +void JITEmitter::initConstantPool(MachineConstantPool *MCP) { >>>>> const std::vector<MachineConstantPoolEntry> &Constants = MCP- >>>>> >>>>> >>>>>> getConstants(); >>>>>> >>>>>> >>>>> if (Constants.empty()) return; >>>>> >>>>> @@ -611,12 +651,15 @@ >>>>> const Type *Ty = CPE.isMachineConstantPoolEntry() >>>>> ? CPE.Val.MachineCPVal->getType() : CPE.Val.ConstVal->getType(); >>>>> Size += TheJIT->getTargetData()->getABITypeSize(Ty); >>>>> - >>>>> + >>>>> ConstantPoolBase = allocateSpace(Size, 1 << MCP- >>>>> >>>>> >>>>>> getConstantPoolAlignment()); >>>>>> >>>>>> >>>>> ConstantPool = MCP; >>>>> +} >>>>> >>>>> +void JITEmitter::emitConstantPool(MachineConstantPool *MCP) { >>>>> if (ConstantPoolBase == 0) return; // Buffer overflow. >>>>> >>>>> + const std::vector<MachineConstantPoolEntry> &Constants = MCP- >>>>> >>>>> >>>>>> getConstants(); >>>>>> >>>>>> >>>>> // Initialize the memory for all of the constant pool entries. >>>>> for (unsigned i = 0, e = Constants.size(); i != e; ++i) { >>>>> void *CAddr = (char*)ConstantPoolBase+Constants[i].Offset; >>>>> _______________________________________________ >>>>> LLVM Developers mailing list >>>>> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu >>>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >>>>> >>>>> >>>> _______________________________________________ >>>> LLVM Developers mailing list >>>> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu >>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >>>> >>>> >>> _______________________________________________ >>> LLVM Developers mailing list >>> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu >>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >>> >> >> _______________________________________________ >> LLVM Developers mailing list >> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu >> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >> > > _______________________________________________ > LLVM Developers mailing list > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
Jonathan S. Shapiro
2008-Apr-04 18:58 UTC
[LLVMdev] Being able to know the jitted code-size before emitting
In general, it is not possible to know jitted code size without emitting. You can suppress the actual write of the instructions themselves, but you have to do all of the work prior to that point. The reason is that on many architectures there are span-dependent branches. The final instruction size depends on the branch span. The span depends on the code size, and the code size depends on the representation of the span. It really is a cyclical dependency, and it is usually solved by doing the best you can and then breaking cycles in the span dependency graph by picking one of the offending spans arbitrarily and fixing it to the max representation length (after which the rest of the dependency loop can be resolved). But the point is that you have to actually generate the code (at least in memory) to do this analysis. You can get a conservative upper bound on those architectures by assuming that all spans will use the maximal sized representation, but you cannot get a precise size without emitting the code. shap
Nicolas Geoffray
2008-Apr-05 06:16 UTC
[LLVMdev] Being able to know the jitted code-size before emitting
Evan Cheng wrote:> > Let's see. ARM has it already. PPC has getNumBytesForInstruction so > you only need to add one to compute function size. Also you only need > to implement it for targets that support JIT right now, which leaves > Alpha and X86. I'm guessing Alpha is using fixed encoding so it should > be pretty easy. Or you can just punt it and let the target maintainers > worry about it. >Yeah, fixed encoding like in PPC is easy to handle.> Really you only need to implement GetFunctionSize for X86 and that's > not as horrible as you think it is. For each instruction: > 1. Compute how many bytes of prefix. The code is there in > X86CodeEmitter except all you need is the size, not the prefixes being > emitted. > 2. For each instruction format, e.g AddRegFrm, MRMDestReg, it's either > only one single byte for opcode or one additional ModR/M byte. Again, > all the information is right there. > 3. Some memory instructions needs a SIB byte. > 4. Process the operands! Some special handling for operands that made > up of the memory address. But the logic is all there in > emitMemModRMByte. > > What do you think? > >That's doable, but I'm afraid I'll have to duplicate many code (eg emitMemModRMByte -> sizeMemModRMByte and probably others). That's not a problem (I'm thinking bug fixes and improvements, we'll have to handle two duplicated code). Nicolas> Evan > > >> >>> Suppose you have the size, can't you pass the desired buffer size to >>> MachineCodeEmitter and have it do the right thing? >>> >> Sure, that's what I'm doing. The emitter with the SizeEmitter class >> will >> give the accurate size to the MachineCodeEmitter. And the >> MachineCodeEmitter will emit the instructions in the buffer. >> >> My solution is surely using things in a way that wasn't intended, >> but it >> works fine and for all targets. Is this really a stopper for >> integrating >> it? (You can see here my laziness on implementing the >> GetFunctionSize to >> every targets :)). >> >> Nicolas >> >> >>> It seems like you >>> can add the functionality to MachineCodeEmitter rather than add a new >>> class for it. >>> >>> Evan >>> >>> >>> >>>> Nicolas >>>> >>>> >>>>> Thanks, >>>>> >>>>> Evan >>>>> >>>>> On Mar 30, 2008, at 12:05 PM, Nicolas Geoffray wrote: >>>>> >>>>> >>>>> >>>>> >>>>>> Hi everyone, >>>>>> >>>>>> vmkit requires to know the size of a jitted method before emitting >>>>>> the method. This allows to allocate the correct size for the >>>>>> method. >>>>>> The attached patch creates this functionality when the flag >>>>>> SizedMemoryCode is on. >>>>>> >>>>>> In order to implement this functionality, i had to virtualize some >>>>>> MachineCodeEmitter functions. >>>>>> >>>>>> Is it OK to commit the patch? >>>>>> >>>>>> Thanks, >>>>>> Nicolas >>>>>> Index: include/llvm/Target/TargetOptions.h >>>>>> = >>>>>> =================================================================>>>>>> --- include/llvm/Target/TargetOptions.h (revision 48944) >>>>>> +++ include/llvm/Target/TargetOptions.h (working copy) >>>>>> @@ -74,6 +74,10 @@ >>>>>> /// be emitted. >>>>>> extern bool ExceptionHandling; >>>>>> >>>>>> + /// SizedMemoryCode - This flags indicates that memory for code >>>>>> is allocated by >>>>>> + /// an external allocator which requires the size to allocate >>>>>> + extern bool SizedMemoryCode; >>>>>> + >>>>>> /// PerformTailCallOpt - This flag is enabled when -tailcallopt is >>>>>> specified >>>>>> /// on the commandline. When the flag is on, the target will >>>>>> perform tail call >>>>>> /// optimization (pop the caller's stack) providing it supports >>>>>> it. >>>>>> Index: include/llvm/CodeGen/SizeEmitter.h >>>>>> = >>>>>> =================================================================>>>>>> --- include/llvm/CodeGen/SizeEmitter.h (revision 0) >>>>>> +++ include/llvm/CodeGen/SizeEmitter.h (revision 0) >>>>>> @@ -0,0 +1,116 @@ >>>>>> +//===-- llvm/CodeGen/MachineCodeEmitter.h - Code emission >>>>>> -------*- >>>>>> C++ -*-===// >>>>>> +// >>>>>> +// The LLVM Compiler Infrastructure >>>>>> +// >>>>>> +// This file was developed by the LLVM research group and is >>>>>> distributed under >>>>>> +// the University of Illinois Open Source License. See >>>>>> LICENSE.TXT >>>>>> for details. >>>>>> +// >>>>>> +// >>>>>> >>>>>> >>>>>> >>>>>> ---------------------------------------------------------------------->>>>>> ==// >>>>>> +// >>>>>> +// This file defines an abstract interface that is used by the >>>>>> machine code >>>>>> +// emission framework to output the code. This allows machine >>>>>> code >>>>>> emission to >>>>>> +// be separated from concerns such as resolution of call targets, >>>>>> and where the >>>>>> +// machine code will be written (memory or disk, f.e.). >>>>>> +// >>>>>> +// >>>>>> >>>>>> >>>>>> >>>>>> ---------------------------------------------------------------------->>>>>> ==// >>>>>> + >>>>>> +#ifndef LLVM_CODEGEN_SIZEEMITTER_H >>>>>> +#define LLVM_CODEGEN_SIZEEMITTER_H >>>>>> + >>>>>> +#include "llvm/CodeGen/MachineCodeEmitter.h" >>>>>> +#include "llvm/CodeGen/MachineFunction.h" >>>>>> + >>>>>> +namespace llvm { >>>>>> + /// SizeEmitter - The JIT implementation of the >>>>>> MachineCodeEmitter, which is >>>>>> + /// used to output functions to memory for execution. >>>>>> +class SizeEmitter : public MachineCodeEmitter { >>>>>> + MachineFunction * Fn; >>>>>> + void* ConstantPoolBase; >>>>>> + void* JumpTableBase; >>>>>> + MachineConstantPool *ConstantPool; >>>>>> + MachineJumpTableInfo *JumpTable; >>>>>> + std::vector<intptr_t> LabelLocations; >>>>>> + MachineCodeEmitter* MCE; >>>>>> + >>>>>> +public: >>>>>> + SizeEmitter(MachineCodeEmitter* mce) { >>>>>> + CurBufferPtr = 0; >>>>>> + BufferBegin = 0; >>>>>> + BufferEnd = (unsigned char*)-1; >>>>>> + MCE = mce; >>>>>> + } >>>>>> + >>>>>> + SizeEmitter(std::vector<intptr_t> locations) { >>>>>> + LabelLocations = locations; >>>>>> + CurBufferPtr = 0; >>>>>> + BufferBegin = 0; >>>>>> + BufferEnd = (unsigned char*)-1; >>>>>> + } >>>>>> + >>>>>> + void initConstantPool(MachineConstantPool *MCP); >>>>>> + >>>>>> + void initJumpTableInfo(MachineJumpTableInfo *MJTI); >>>>>> + >>>>>> + >>>>>> + virtual void startFunction(MachineFunction &F) { >>>>>> + CurBufferPtr = 0; >>>>>> + Fn = &F; >>>>>> + >>>>>> + // Ensure the constant pool/jump table info is at least 4- >>>>>> byte >>>>>> aligned. >>>>>> + emitAlignment(16); >>>>>> + >>>>>> + initConstantPool(F.getConstantPool()); >>>>>> + initJumpTableInfo(F.getJumpTableInfo()); >>>>>> + >>>>>> + ConstantPoolBase = (void*)(((uintptr_t) ConstantPoolBase) + >>>>>> CurBufferPtr); >>>>>> + JumpTableBase = (void*)(((uintptr_t) JumpTableBase) + >>>>>> CurBufferPtr); >>>>>> + } >>>>>> + >>>>>> + virtual bool finishFunction(MachineFunction &F) { >>>>>> + MCE->setCurrentPtr(CurBufferPtr); >>>>>> + return false; >>>>>> + } >>>>>> + virtual void startFunctionStub(unsigned StubSize, unsigned >>>>>> Alignment) {} >>>>>> + virtual void *finishFunctionStub(const Function *F) { return >>>>>> 0; } >>>>>> + virtual void addRelocation(const llvm::MachineRelocation&) { } >>>>>> + virtual void emitByte(unsigned char B) { >>>>>> + CurBufferPtr++; >>>>>> + } >>>>>> + virtual void emitWordLE(unsigned W) { >>>>>> + CurBufferPtr+=4; >>>>>> + } >>>>>> + virtual void emitWordBE(unsigned W) { >>>>>> + CurBufferPtr+=4; >>>>>> + } >>>>>> + virtual void emitInt32(int Value) { >>>>>> + CurBufferPtr += 4; >>>>>> + } >>>>>> + virtual void emitInt64(uint64_t Value) { >>>>>> + CurBufferPtr += 8; >>>>>> + } >>>>>> + virtual void emitAt(uintptr_t *Addr, uintptr_t Value) { >>>>>> + } >>>>>> + >>>>>> + >>>>>> + >>>>>> + virtual void StartMachineBasicBlock(MachineBasicBlock *MBB) {} >>>>>> + virtual intptr_t getConstantPoolEntryAddress(unsigned >>>>>> ConstantNum) const; >>>>>> + >>>>>> + virtual intptr_t getJumpTableEntryAddress(unsigned Index) >>>>>> const; >>>>>> + >>>>>> + virtual intptr_t getMachineBasicBlockAddress(MachineBasicBlock >>>>>> *MBB) const { >>>>>> + assert(0 && "Should not be in getMachineBasicBlockAddress of >>>>>> SizeEmitter"); >>>>>> + } >>>>>> + >>>>>> + virtual void emitLabel(uint64_t) {} >>>>>> + virtual intptr_t getLabelAddress(uint64_t LabelID) const { >>>>>> + assert(LabelLocations.size() > (unsigned)LabelID && >>>>>> + LabelLocations[LabelID] && "Label not emitted!"); >>>>>> + return LabelLocations[LabelID]; >>>>>> + } >>>>>> + virtual void setModuleInfo(llvm::MachineModuleInfo*) {} >>>>>> +}; >>>>>> + >>>>>> +} // end llvm namespace >>>>>> + >>>>>> +#endif >>>>>> Index: include/llvm/CodeGen/MachineCodeEmitter.h >>>>>> = >>>>>> =================================================================>>>>>> --- include/llvm/CodeGen/MachineCodeEmitter.h (revision 48143) >>>>>> +++ include/llvm/CodeGen/MachineCodeEmitter.h (working copy) >>>>>> @@ -18,6 +18,7 @@ >>>>>> #define LLVM_CODEGEN_MACHINECODEEMITTER_H >>>>>> >>>>>> #include "llvm/Support/DataTypes.h" >>>>>> +#include <string> >>>>>> #include <vector> >>>>>> >>>>>> namespace llvm { >>>>>> @@ -92,7 +93,7 @@ >>>>>> /// emitByte - This callback is invoked when a byte needs to be >>>>>> written to the >>>>>> /// output stream. >>>>>> /// >>>>>> - void emitByte(unsigned char B) { >>>>>> + virtual void emitByte(unsigned char B) { >>>>>> if (CurBufferPtr != BufferEnd) >>>>>> *CurBufferPtr++ = B; >>>>>> } >>>>>> @@ -100,7 +101,7 @@ >>>>>> /// emitWordLE - This callback is invoked when a 32-bit word needs >>>>>> to be >>>>>> /// written to the output stream in little-endian format. >>>>>> /// >>>>>> - void emitWordLE(unsigned W) { >>>>>> + virtual void emitWordLE(unsigned W) { >>>>>> if (CurBufferPtr+4 <= BufferEnd) { >>>>>> *CurBufferPtr++ = (unsigned char)(W >> 0); >>>>>> *CurBufferPtr++ = (unsigned char)(W >> 8); >>>>>> @@ -114,7 +115,7 @@ >>>>>> /// emitWordBE - This callback is invoked when a 32-bit word needs >>>>>> to be >>>>>> /// written to the output stream in big-endian format. >>>>>> /// >>>>>> - void emitWordBE(unsigned W) { >>>>>> + virtual void emitWordBE(unsigned W) { >>>>>> if (CurBufferPtr+4 <= BufferEnd) { >>>>>> *CurBufferPtr++ = (unsigned char)(W >> 24); >>>>>> *CurBufferPtr++ = (unsigned char)(W >> 16); >>>>>> @@ -175,7 +176,7 @@ >>>>>> } >>>>>> >>>>>> /// emitInt32 - Emit a int32 directive. >>>>>> - void emitInt32(int Value) { >>>>>> + virtual void emitInt32(int Value) { >>>>>> if (CurBufferPtr+4 <= BufferEnd) { >>>>>> *((uint32_t*)CurBufferPtr) = Value; >>>>>> CurBufferPtr += 4; >>>>>> @@ -185,7 +186,7 @@ >>>>>> } >>>>>> >>>>>> /// emitInt64 - Emit a int64 directive. >>>>>> - void emitInt64(uint64_t Value) { >>>>>> + virtual void emitInt64(uint64_t Value) { >>>>>> if (CurBufferPtr+8 <= BufferEnd) { >>>>>> *((uint64_t*)CurBufferPtr) = Value; >>>>>> CurBufferPtr += 8; >>>>>> @@ -195,7 +196,7 @@ >>>>>> } >>>>>> >>>>>> /// emitAt - Emit Value in Addr >>>>>> - void emitAt(uintptr_t *Addr, uintptr_t Value) { >>>>>> + virtual void emitAt(uintptr_t *Addr, uintptr_t Value) { >>>>>> if (Addr >= (uintptr_t*)BufferBegin && Addr < >>>>>> (uintptr_t*)BufferEnd) >>>>>> (*Addr) = Value; >>>>>> } >>>>>> @@ -270,6 +271,11 @@ >>>>>> /// Specifies the MachineModuleInfo object. This is used for >>>>>> exception handling >>>>>> /// purposes. >>>>>> virtual void setModuleInfo(MachineModuleInfo* Info) = 0; >>>>>> + >>>>>> + void setCurrentPtr(unsigned char* Ptr) { >>>>>> + CurBufferPtr = Ptr; >>>>>> + } >>>>>> + >>>>>> }; >>>>>> >>>>>> } // End llvm namespace >>>>>> Index: lib/CodeGen/LLVMTargetMachine.cpp >>>>>> = >>>>>> =================================================================>>>>>> --- lib/CodeGen/LLVMTargetMachine.cpp (revision 48143) >>>>>> +++ lib/CodeGen/LLVMTargetMachine.cpp (working copy) >>>>>> @@ -17,6 +17,7 @@ >>>>>> #include "llvm/Assembly/PrintModulePass.h" >>>>>> #include "llvm/Analysis/LoopPass.h" >>>>>> #include "llvm/CodeGen/Passes.h" >>>>>> +#include "llvm/CodeGen/SizeEmitter.h" >>>>>> #include "llvm/CodeGen/Collector.h" >>>>>> #include "llvm/Target/TargetOptions.h" >>>>>> #include "llvm/Transforms/Scalar.h" >>>>>> @@ -257,7 +258,13 @@ >>>>>> >>>>>> if (addPreEmitPass(PM, Fast) && PrintMachineCode) >>>>>> PM.add(createMachineFunctionPrinterPass(cerr)); >>>>>> + >>>>>> + if (SizedMemoryCode) { >>>>>> + SizeEmitter * SE = new SizeEmitter(&MCE); >>>>>> + addSimpleCodeEmitter(PM, Fast, false, *SE); >>>>>> + } >>>>>> >>>>>> + >>>>>> addCodeEmitter(PM, Fast, PrintEmittedAsm, MCE); >>>>>> >>>>>> PM.add(createCollectorMetadataDeleter()); >>>>>> Index: lib/CodeGen/SizeEmitter.cpp >>>>>> = >>>>>> =================================================================>>>>>> --- lib/CodeGen/SizeEmitter.cpp (revision 0) >>>>>> +++ lib/CodeGen/SizeEmitter.cpp (revision 0) >>>>>> @@ -0,0 +1,77 @@ >>>>>> +#include "llvm/CodeGen/SizeEmitter.h" >>>>>> +#include "llvm/Constant.h" >>>>>> +#include "llvm/Constants.h" >>>>>> +#include "llvm/DerivedTypes.h" >>>>>> +#include "llvm/Module.h" >>>>>> +#include "llvm/Type.h" >>>>>> +#include "llvm/CodeGen/MachineCodeEmitter.h" >>>>>> +#include "llvm/CodeGen/MachineFunction.h" >>>>>> +#include "llvm/CodeGen/MachineConstantPool.h" >>>>>> +#include "llvm/CodeGen/MachineJumpTableInfo.h" >>>>>> +#include "llvm/CodeGen/MachineRelocation.h" >>>>>> +#include "llvm/ExecutionEngine/GenericValue.h" >>>>>> +#include "llvm/Target/TargetData.h" >>>>>> +#include "llvm/Target/TargetJITInfo.h" >>>>>> +#include "llvm/Target/TargetMachine.h" >>>>>> +#include "llvm/Target/TargetOptions.h" >>>>>> +#include "llvm/Support/Debug.h" >>>>>> +#include "llvm/Support/MutexGuard.h" >>>>>> +#include "llvm/System/Disassembler.h" >>>>>> +#include "llvm/ADT/Statistic.h" >>>>>> +#include "llvm/System/Memory.h" >>>>>> +#include <algorithm> >>>>>> +using namespace llvm; >>>>>> + >>>>>> + >>>>>> +void SizeEmitter::initConstantPool(MachineConstantPool *MCP) { >>>>>> + const std::vector<MachineConstantPoolEntry> &Constants = MCP- >>>>>> >>>>>> >>>>>> >>>>>>> getConstants(); >>>>>>> >>>>>>> >>>>>>> >>>>>> + if (Constants.empty()) return; >>>>>> + >>>>>> + MachineConstantPoolEntry CPE = Constants.back(); >>>>>> + unsigned Size = CPE.Offset; >>>>>> + const Type *Ty = CPE.isMachineConstantPoolEntry() >>>>>> + ? CPE.Val.MachineCPVal->getType() : CPE.Val.ConstVal- >>>>>> >>>>>> >>>>>>> getType(); >>>>>>> >>>>>>> >>>>>> + Size += Fn->getTarget().getTargetData()->getABITypeSize(Ty); >>>>>> + ConstantPoolBase = allocateSpace(Size, 1 << MCP- >>>>>> >>>>>> >>>>>> >>>>>>> getConstantPoolAlignment()); >>>>>>> >>>>>>> >>>>>>> >>>>>> + ConstantPool = MCP; >>>>>> +} >>>>>> + >>>>>> +void SizeEmitter::initJumpTableInfo(MachineJumpTableInfo *MJTI) { >>>>>> + const std::vector<MachineJumpTableEntry> &JT = MJTI- >>>>>> >>>>>> >>>>>> >>>>>>> getJumpTables(); >>>>>>> >>>>>>> >>>>>>> >>>>>> + if (JT.empty()) return; >>>>>> + >>>>>> + unsigned NumEntries = 0; >>>>>> + for (unsigned i = 0, e = JT.size(); i != e; ++i) >>>>>> + NumEntries += JT[i].MBBs.size(); >>>>>> + >>>>>> + unsigned EntrySize = MJTI->getEntrySize(); >>>>>> + >>>>>> + // Just allocate space for all the jump tables now. We will >>>>>> fix >>>>>> up the actual >>>>>> + // MBB entries in the tables after we emit the code for each >>>>>> block, since then >>>>>> + // we will know the final locations of the MBBs in memory. >>>>>> + JumpTable = MJTI; >>>>>> + JumpTableBase = allocateSpace(NumEntries * EntrySize, MJTI- >>>>>> >>>>>> >>>>>> >>>>>>> getAlignment()); >>>>>>> >>>>>>> >>>>>>> >>>>>> +} >>>>>> + >>>>>> +intptr_t SizeEmitter::getConstantPoolEntryAddress(unsigned >>>>>> ConstantNum) const { >>>>>> + assert(ConstantNum < ConstantPool->getConstants().size() && >>>>>> + "Invalid ConstantPoolIndex!"); >>>>>> + return (intptr_t)ConstantPoolBase + >>>>>> + ConstantPool->getConstants()[ConstantNum].Offset; >>>>>> +} >>>>>> + >>>>>> +intptr_t SizeEmitter::getJumpTableEntryAddress(unsigned Index) >>>>>> const { >>>>>> + const std::vector<MachineJumpTableEntry> &JT = JumpTable- >>>>>> >>>>>> >>>>>> >>>>>>> getJumpTables(); >>>>>>> >>>>>>> >>>>>>> >>>>>> + assert(Index < JT.size() && "Invalid jump table index!"); >>>>>> + >>>>>> + unsigned Offset = 0; >>>>>> + unsigned EntrySize = JumpTable->getEntrySize(); >>>>>> + >>>>>> + for (unsigned i = 0; i < Index; ++i) >>>>>> + Offset += JT[i].MBBs.size(); >>>>>> + >>>>>> + Offset *= EntrySize; >>>>>> + >>>>>> + return (intptr_t)((char *)JumpTableBase + Offset); >>>>>> +} >>>>>> + >>>>>> Index: lib/Target/TargetMachine.cpp >>>>>> = >>>>>> =================================================================>>>>>> --- lib/Target/TargetMachine.cpp (revision 48143) >>>>>> +++ lib/Target/TargetMachine.cpp (working copy) >>>>>> @@ -31,6 +31,7 @@ >>>>>> bool UseSoftFloat; >>>>>> bool NoZerosInBSS; >>>>>> bool ExceptionHandling; >>>>>> + bool SizedMemoryCode; >>>>>> Reloc::Model RelocationModel; >>>>>> CodeModel::Model CMModel; >>>>>> bool PerformTailCallOpt; >>>>>> Index: lib/ExecutionEngine/JIT/JITEmitter.cpp >>>>>> = >>>>>> =================================================================>>>>>> --- lib/ExecutionEngine/JIT/JITEmitter.cpp (revision 48143) >>>>>> +++ lib/ExecutionEngine/JIT/JITEmitter.cpp (working copy) >>>>>> @@ -18,12 +18,14 @@ >>>>>> #include "llvm/Constant.h" >>>>>> #include "llvm/Module.h" >>>>>> #include "llvm/Type.h" >>>>>> +#include "llvm/ADT/DenseMap.h" >>>>>> #include "llvm/CodeGen/MachineCodeEmitter.h" >>>>>> #include "llvm/CodeGen/MachineFunction.h" >>>>>> #include "llvm/CodeGen/MachineConstantPool.h" >>>>>> #include "llvm/CodeGen/MachineJumpTableInfo.h" >>>>>> #include "llvm/CodeGen/MachineModuleInfo.h" >>>>>> #include "llvm/CodeGen/MachineRelocation.h" >>>>>> +#include "llvm/CodeGen/SizeEmitter.h" >>>>>> #include "llvm/ExecutionEngine/JITMemoryManager.h" >>>>>> #include "llvm/Target/TargetData.h" >>>>>> #include "llvm/Target/TargetJITInfo.h" >>>>>> @@ -370,6 +376,7 @@ >>>>>> virtual void startFunction(MachineFunction &F); >>>>>> virtual bool finishFunction(MachineFunction &F); >>>>>> >>>>>> + void initConstantPool(MachineConstantPool *MCP); >>>>>> void emitConstantPool(MachineConstantPool *MCP); >>>>>> void initJumpTableInfo(MachineJumpTableInfo *MJTI); >>>>>> void emitJumpTableInfo(MachineJumpTableInfo *MJTI); >>>>>> @@ -469,19 +476,47 @@ >>>>>> >>>>>> >>>>>> void JITEmitter::startFunction(MachineFunction &F) { >>>>>> - uintptr_t ActualSize; >>>>>> - BufferBegin = CurBufferPtr = MemMgr- >>>>>> >>>>>> >>>>>> >>>>>>> startFunctionBody(F.getFunction(), >>>>>>> >>>>>>> >>>>>>> >>>>>> - >>>>>> ActualSize); >>>>>> - BufferEnd = BufferBegin+ActualSize; >>>>>> + MMI->BeginFunction(&F); >>>>>> >>>>>> - // Ensure the constant pool/jump table info is at least 4-byte >>>>>> aligned. >>>>>> - emitAlignment(16); >>>>>> + if (SizedMemoryCode) { >>>>>> + BufferBegin = CurBufferPtr; >>>>>> + BufferEnd = (unsigned char*) 0xffffffff; >>>>>> + >>>>>> + // Ensure the constant pool/jump table info is at least 4- >>>>>> byte >>>>>> aligned. >>>>>> + emitAlignment(16); >>>>>> >>>>>> - emitConstantPool(F.getConstantPool()); >>>>>> - initJumpTableInfo(F.getJumpTableInfo()); >>>>>> + initConstantPool(F.getConstantPool()); >>>>>> + initJumpTableInfo(F.getJumpTableInfo()); >>>>>> + >>>>>> + >>>>>> + uintptr_t ActualSize = (uintptr_t)CurBufferPtr; >>>>>> + CurBufferPtr = MemMgr->startFunctionBody(F.getFunction(), >>>>>> + ActualSize); >>>>>> + >>>>>> + ConstantPoolBase = (void*)(((unsigned) ConstantPoolBase) + >>>>>> CurBufferPtr); >>>>>> + JumpTableBase = (void*)(((unsigned) JumpTableBase) + >>>>>> CurBufferPtr); >>>>>> >>>>>> - // About to start emitting the machine code for the function. >>>>>> - emitAlignment(std::max(F.getFunction()->getAlignment(), 8U)); >>>>>> + emitConstantPool(F.getConstantPool()); >>>>>> + >>>>>> + } else { >>>>>> + uintptr_t ActualSize; >>>>>> + 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); >>>>>> + >>>>>> + initConstantPool(F.getConstantPool()); >>>>>> + 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(); >>>>>> @@ -579,12 +614,18 @@ >>>>>> DOUT << "Disassembled code:\n" >>>>>> << sys::disassembleBuffer(FnStart, FnEnd-FnStart, >>>>>> (uintptr_t)FnStart); >>>>>> #endif >>>>>> + >>>>>> if (ExceptionHandling) { >>>>>> uintptr_t ActualSize; >>>>>> + if (SizedMemoryCode) { >>>>>> + SizeEmitter sz(LabelLocations); >>>>>> + DE->EmitDwarfTable(F, sz, FnStart, FnEnd); >>>>>> + ActualSize = sz.getCurrentPCValue(); >>>>>> + } >>>>>> SavedBufferBegin = BufferBegin; >>>>>> SavedBufferEnd = BufferEnd; >>>>>> SavedCurBufferPtr = CurBufferPtr; >>>>>> - >>>>>> + >>>>>> BufferBegin = CurBufferPtr = MemMgr- >>>>>> >>>>>> >>>>>> >>>>>>> startExceptionTable(F.getFunction(), >>>>>>> >>>>>>> >>>>>>> >>>>>> ActualSize); >>>>>> BufferEnd = BufferBegin+ActualSize; >>>>>> @@ -598,11 +639,10 @@ >>>>>> TheJIT->RegisterTable(FrameRegister); >>>>>> } >>>>>> MMI->EndFunction(); >>>>>> - >>>>>> return false; >>>>>> } >>>>>> >>>>>> -void JITEmitter::emitConstantPool(MachineConstantPool *MCP) { >>>>>> +void JITEmitter::initConstantPool(MachineConstantPool *MCP) { >>>>>> const std::vector<MachineConstantPoolEntry> &Constants = MCP- >>>>>> >>>>>> >>>>>> >>>>>>> getConstants(); >>>>>>> >>>>>>> >>>>>>> >>>>>> if (Constants.empty()) return; >>>>>> >>>>>> @@ -611,12 +651,15 @@ >>>>>> const Type *Ty = CPE.isMachineConstantPoolEntry() >>>>>> ? CPE.Val.MachineCPVal->getType() : CPE.Val.ConstVal->getType(); >>>>>> Size += TheJIT->getTargetData()->getABITypeSize(Ty); >>>>>> - >>>>>> + >>>>>> ConstantPoolBase = allocateSpace(Size, 1 << MCP- >>>>>> >>>>>> >>>>>> >>>>>>> getConstantPoolAlignment()); >>>>>>> >>>>>>> >>>>>>> >>>>>> ConstantPool = MCP; >>>>>> +} >>>>>> >>>>>> +void JITEmitter::emitConstantPool(MachineConstantPool *MCP) { >>>>>> if (ConstantPoolBase == 0) return; // Buffer overflow. >>>>>> >>>>>> + const std::vector<MachineConstantPoolEntry> &Constants = MCP- >>>>>> >>>>>> >>>>>> >>>>>>> getConstants(); >>>>>>> >>>>>>> >>>>>>> >>>>>> // Initialize the memory for all of the constant pool entries. >>>>>> for (unsigned i = 0, e = Constants.size(); i != e; ++i) { >>>>>> void *CAddr = (char*)ConstantPoolBase+Constants[i].Offset; >>>>>> _______________________________________________ >>>>>> LLVM Developers mailing list >>>>>> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu >>>>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >>>>>> >>>>>> >>>>>> >>>>> _______________________________________________ >>>>> LLVM Developers mailing list >>>>> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu >>>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >>>>> >>>>> >>>>> >>>> _______________________________________________ >>>> LLVM Developers mailing list >>>> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu >>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >>>> >>>> >>> _______________________________________________ >>> LLVM Developers mailing list >>> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu >>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >>> >>> >> _______________________________________________ >> LLVM Developers mailing list >> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu >> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >> > > _______________________________________________ > LLVM Developers mailing list > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >
Apparently Analagous Threads
- [LLVMdev] Being able to know the jitted code-size before emitting
- [LLVMdev] Being able to know the jitted code-size before emitting
- [LLVMdev] Being able to know the jitted code-size before emitting
- [LLVMdev] Being able to know the jitted code-size before emitting
- [LLVMdev] Being able to know the jitted code-size before emitting