From 43b429b05989075b60693d57395c99b0ad789f8d Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Tue, 2 May 2006 18:27:26 +0000 Subject: [PATCH] Refactor the machine code emitter interface to pull the pointers for the current code emission location into the base class, instead of being in the derived classes. This change means that low-level methods like emitByte/emitWord now are no longer virtual (yaay for speed), and we now have a framework to support growable code segments. This implements feature request #1 of PR469. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@28059 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/CodeGen/MachineCodeEmitter.h | 70 +++++++++--- lib/CodeGen/ELFWriter.cpp | 21 ++-- lib/CodeGen/MachineCodeEmitter.cpp | 131 ---------------------- lib/ExecutionEngine/JIT/JITEmitter.cpp | 83 +++++--------- lib/Target/Alpha/AlphaCodeEmitter.cpp | 14 ++- lib/Target/PowerPC/PPCCodeEmitter.cpp | 18 +-- lib/Target/X86/X86CodeEmitter.cpp | 18 +-- 7 files changed, 124 insertions(+), 231 deletions(-) delete mode 100644 lib/CodeGen/MachineCodeEmitter.cpp diff --git a/include/llvm/CodeGen/MachineCodeEmitter.h b/include/llvm/CodeGen/MachineCodeEmitter.h index 47ccef5317a..72002ef8977 100644 --- a/include/llvm/CodeGen/MachineCodeEmitter.h +++ b/include/llvm/CodeGen/MachineCodeEmitter.h @@ -31,19 +31,50 @@ class Value; class GlobalValue; class Function; +/// MachineCodeEmitter - This class defines two sorts of methods: those for +/// emitting the actual bytes of machine code, and those for emitting auxillary +/// structures, such as jump tables, relocations, etc. +/// +/// Emission of machine code is complicated by the fact that we don't (in +/// general) know the size of the machine code that we're about to emit before +/// we emit it. As such, we preallocate a certain amount of memory, and set the +/// BufferBegin/BufferEnd pointers to the start and end of the buffer. As we +/// emit machine instructions, we advance the CurBufferPtr to indicate the +/// location of the next byte to emit. In the case of a buffer overflow (we +/// need to emit more machine code than we have allocated space for), the +/// CurBufferPtr will saturate to BufferEnd and ignore stores. Once the entire +/// function has been emitted, the overflow condition is checked, and if it has +/// occurred, more memory is allocated, and we reemit the code into it. +/// class MachineCodeEmitter { +protected: + /// BufferBegin/BufferEnd - Pointers to the start and end of the memory + /// allocated for this code buffer. + unsigned char *BufferBegin, *BufferEnd; + + /// CurBufferPtr - Pointer to the next byte of memory to fill when emitting + /// code. This is guranteed to be in the range [BufferBegin,BufferEnd]. If + /// this pointer is at BufferEnd, it will never move due to code emission, and + /// all code emission requests will be ignored (this is the buffer overflow + /// condition). + unsigned char *CurBufferPtr; public: virtual ~MachineCodeEmitter() {} /// startFunction - This callback is invoked when the specified function is - /// about to be code generated. + /// about to be code generated. This initializes the BufferBegin/End/Ptr + /// fields. /// virtual void startFunction(MachineFunction &F) {} /// finishFunction - This callback is invoked when the specified function has - /// finished code generation. + /// finished code generation. If a buffer overflow has occurred, this method + /// returns true (the callee is required to try again), otherwise it returns + /// false. /// - virtual void finishFunction(MachineFunction &F) {} + virtual bool finishFunction(MachineFunction &F) { + return CurBufferPtr == BufferEnd; + } /// emitConstantPool - This callback is invoked to output the constant pool /// for the function. @@ -63,7 +94,8 @@ public: /// startFunctionStub - This callback is invoked when the JIT needs the /// address of a function that has not been code generated yet. The StubSize /// specifies the total size required by the stub. Stubs are not allowed to - /// have constant pools, the can only use the other emit* methods. + /// have constant pools, the can only use the other emitByte*/emitWord* + /// methods. /// virtual void startFunctionStub(unsigned StubSize) {} @@ -75,22 +107,36 @@ public: /// emitByte - This callback is invoked when a byte needs to be written to the /// output stream. /// - virtual void emitByte(unsigned char B) {} + void emitByte(unsigned char B) { + if (CurBufferPtr != BufferEnd) + *CurBufferPtr++ = B; + } /// emitWord - This callback is invoked when a word needs to be written to the /// output stream. /// - virtual void emitWord(unsigned W) = 0; + void emitWord(unsigned W) { + // FIXME: handle endian mismatches for .o file emission. + if (CurBufferPtr+4 <= BufferEnd) { + *(unsigned*)CurBufferPtr = W; + CurBufferPtr += 4; + } else { + CurBufferPtr = BufferEnd; + } + } /// getCurrentPCValue - This returns the address that the next emitted byte /// will be output to. /// - virtual uint64_t getCurrentPCValue() = 0; - + virtual intptr_t getCurrentPCValue() const { + return (intptr_t)CurBufferPtr; + } /// getCurrentPCOffset - Return the offset from the start of the emitted /// buffer that we are currently writing to. - virtual uint64_t getCurrentPCOffset() = 0; + intptr_t getCurrentPCOffset() const { + return CurBufferPtr-BufferBegin; + } /// addRelocation - Whenever a relocatable address is needed, it should be /// noted with this interface. @@ -108,12 +154,6 @@ public: // allocateGlobal - Allocate some space for a global variable. virtual unsigned char* allocateGlobal(unsigned size, unsigned alignment) = 0; - - /// createFilePrinterEmitter - Return a dynamically allocated - /// machine code emitter, which prints binary code to a file. This - /// can be used for debugging users of the MachineCodeEmitter interface. - /// - static MachineCodeEmitter *createFilePrinterEmitter(MachineCodeEmitter&); }; } // End llvm namespace diff --git a/lib/CodeGen/ELFWriter.cpp b/lib/CodeGen/ELFWriter.cpp index a802c1aa793..c03b6272b56 100644 --- a/lib/CodeGen/ELFWriter.cpp +++ b/lib/CodeGen/ELFWriter.cpp @@ -56,24 +56,12 @@ namespace llvm { ELFCodeEmitter(ELFWriter &ew) : EW(ew), OutBuffer(0) {} void startFunction(MachineFunction &F); - void finishFunction(MachineFunction &F); + bool finishFunction(MachineFunction &F); void emitConstantPool(MachineConstantPool *MCP) { if (MCP->isEmpty()) return; assert(0 && "unimp"); } - virtual void emitByte(unsigned char B) { - OutBuffer->push_back(B); - } - virtual void emitWord(unsigned W) { - assert(0 && "ni"); - } - virtual uint64_t getCurrentPCValue() { - return OutBuffer->size(); - } - virtual uint64_t getCurrentPCOffset() { - return OutBuffer->size()-FnStart; - } void addRelocation(const MachineRelocation &MR) { assert(0 && "relo not handled yet!"); } @@ -113,6 +101,10 @@ void ELFCodeEmitter::startFunction(MachineFunction &F) { ELFWriter::ELFSection::SHF_EXECINSTR | ELFWriter::ELFSection::SHF_ALLOC); OutBuffer = &ES->SectionData; + std::cerr << "FIXME: This code needs to be updated for changes in the" + << " CodeEmitter interfaces. In particular, this should set " + << "BufferBegin/BufferEnd/CurBufferPtr, not deal with OutBuffer!"; + abort(); // Upgrade the section alignment if required. if (ES->Align < Align) ES->Align = Align; @@ -127,7 +119,7 @@ void ELFCodeEmitter::startFunction(MachineFunction &F) { /// finishFunction - This callback is invoked after the function is completely /// finished. -void ELFCodeEmitter::finishFunction(MachineFunction &F) { +bool ELFCodeEmitter::finishFunction(MachineFunction &F) { // We now know the size of the function, add a symbol to represent it. ELFWriter::ELFSym FnSym(F.getFunction()); @@ -157,6 +149,7 @@ void ELFCodeEmitter::finishFunction(MachineFunction &F) { // Finally, add it to the symtab. EW.SymbolTable.push_back(FnSym); + return false; } //===----------------------------------------------------------------------===// diff --git a/lib/CodeGen/MachineCodeEmitter.cpp b/lib/CodeGen/MachineCodeEmitter.cpp deleted file mode 100644 index 301d9afb8ae..00000000000 --- a/lib/CodeGen/MachineCodeEmitter.cpp +++ /dev/null @@ -1,131 +0,0 @@ -//===-- MachineCodeEmitter.cpp - Implement the MachineCodeEmitter itf -----===// -// -// 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 implements the MachineCodeEmitter interface. -// -//===----------------------------------------------------------------------===// - -#include "llvm/CodeGen/MachineCodeEmitter.h" -#include -#include -using namespace llvm; - -namespace { - class FilePrinterEmitter : public MachineCodeEmitter { - std::ofstream actual; - std::ostream &o; - MachineCodeEmitter &MCE; - unsigned counter; - unsigned values[4]; - - public: - FilePrinterEmitter(MachineCodeEmitter &M, std::ostream &os) - : o(os), MCE(M), counter(0) { - openActual(); - } - - ~FilePrinterEmitter() { - o << "\n"; - actual.close(); - } - - void openActual() { - actual.open("lli.actual.obj"); - if (!actual.good()) { - std::cerr << "Cannot open 'lli.actual.obj' for writing\n"; - abort(); - } - } - - void startFunction(MachineFunction &F) { - // resolve any outstanding calls - MCE.startFunction(F); - } - void finishFunction(MachineFunction &F) { - MCE.finishFunction(F); - } - - void emitConstantPool(MachineConstantPool *MCP) { - MCE.emitConstantPool(MCP); - } - void initJumpTableInfo(MachineJumpTableInfo *MJTI) { - MCE.initJumpTableInfo(MJTI); - } - void emitJumpTableInfo(MachineJumpTableInfo *MJTI, - std::map &MBBM) { - MCE.emitJumpTableInfo(MJTI, MBBM); - } - - void startFunctionStub(unsigned StubSize) { - MCE.startFunctionStub(StubSize); - } - - void *finishFunctionStub(const Function *F) { - return MCE.finishFunctionStub(F); - } - - void emitByte(unsigned char B) { - MCE.emitByte(B); - actual << B; actual.flush(); - - values[counter] = (unsigned int) B; - if (++counter % 4 == 0 && counter != 0) { - o << std::hex; - for (unsigned i=0; i<4; ++i) { - if (values[i] < 16) o << "0"; - o << values[i] << " "; - } - - o << std::dec << "\t"; - for (unsigned i=0; i<4; ++i) { - for (int j=7; j>=0; --j) { - o << ((values[i] >> j) & 1); - } - o << " "; - } - - o << "\n"; - - unsigned instr = 0; - for (unsigned i=0; i<4; ++i) - instr |= values[i] << (i*8); - - o << "--- * --- * --- * --- * ---\n"; - counter %= 4; - } - } - - void emitWord(unsigned W) { - MCE.emitWord(W); - } - uint64_t getConstantPoolEntryAddress(unsigned Num) { - return MCE.getConstantPoolEntryAddress(Num); - } - uint64_t getJumpTableEntryAddress(unsigned Num) { - return MCE.getJumpTableEntryAddress(Num); - } - virtual unsigned char* allocateGlobal(unsigned size, unsigned alignment) - { return MCE.allocateGlobal(size, alignment); } - - uint64_t getCurrentPCValue() { - return MCE.getCurrentPCValue(); - } - uint64_t getCurrentPCOffset() { - return MCE.getCurrentPCOffset(); - } - void addRelocation(const MachineRelocation &MR) { - return MCE.addRelocation(MR); - } - }; -} - -MachineCodeEmitter * -MachineCodeEmitter::createFilePrinterEmitter(MachineCodeEmitter &MCE) { - return new FilePrinterEmitter(MCE, std::cerr); -} diff --git a/lib/ExecutionEngine/JIT/JITEmitter.cpp b/lib/ExecutionEngine/JIT/JITEmitter.cpp index cbe8f7af555..108b6b85833 100644 --- a/lib/ExecutionEngine/JIT/JITEmitter.cpp +++ b/lib/ExecutionEngine/JIT/JITEmitter.cpp @@ -413,13 +413,9 @@ namespace { class JITEmitter : public MachineCodeEmitter { JITMemoryManager MemMgr; - // CurBlock - The start of the current block of memory. CurByte - The - // current byte being emitted to. - unsigned char *CurBlock, *CurByte; - // When outputting a function stub in the context of some other function, we - // save CurBlock and CurByte here. - unsigned char *SavedCurBlock, *SavedCurByte; + // save BufferBegin/BufferEnd/CurBufferPtr here. + unsigned char *SavedBufferBegin, *SavedBufferEnd, *SavedCurBufferPtr; /// Relocations - These are the relocations that the function needs, as /// emitted. @@ -449,22 +445,18 @@ public: } virtual void startFunction(MachineFunction &F); - virtual void finishFunction(MachineFunction &F); + virtual bool finishFunction(MachineFunction &F); virtual void emitConstantPool(MachineConstantPool *MCP); virtual void initJumpTableInfo(MachineJumpTableInfo *MJTI); virtual void emitJumpTableInfo(MachineJumpTableInfo *MJTI, std::map &MBBM); virtual void startFunctionStub(unsigned StubSize); virtual void* finishFunctionStub(const Function *F); - virtual void emitByte(unsigned char B); - virtual void emitWord(unsigned W); virtual void addRelocation(const MachineRelocation &MR) { Relocations.push_back(MR); } - virtual uint64_t getCurrentPCValue(); - virtual uint64_t getCurrentPCOffset(); virtual uint64_t getConstantPoolEntryAddress(unsigned Entry); virtual uint64_t getJumpTableEntryAddress(unsigned Entry); virtual unsigned char* allocateGlobal(unsigned size, unsigned alignment); @@ -511,13 +503,16 @@ void *JITEmitter::getPointerToGlobal(GlobalValue *V, void *Reference, } void JITEmitter::startFunction(MachineFunction &F) { - CurByte = CurBlock = MemMgr.startFunctionBody(); - TheJIT->addGlobalMapping(F.getFunction(), CurBlock); + BufferBegin = CurBufferPtr = MemMgr.startFunctionBody(); + TheJIT->updateGlobalMapping(F.getFunction(), BufferBegin); + + /// FIXME: implement out of space handling correctly! + BufferEnd = (unsigned char*)(intptr_t)~0ULL; } -void JITEmitter::finishFunction(MachineFunction &F) { - MemMgr.endFunctionBody(CurByte); - NumBytes += CurByte-CurBlock; +bool JITEmitter::finishFunction(MachineFunction &F) { + MemMgr.endFunctionBody(CurBufferPtr); + NumBytes += getCurrentPCOffset(); if (!Relocations.empty()) { NumRelos += Relocations.size(); @@ -534,7 +529,7 @@ void JITEmitter::finishFunction(MachineFunction &F) { ResultPtr = getJITResolver(this).getExternalFunctionStub(ResultPtr); } else if (MR.isGlobalValue()) ResultPtr = getPointerToGlobal(MR.getGlobalValue(), - CurBlock+MR.getMachineCodeOffset(), + BufferBegin+MR.getMachineCodeOffset(), MR.doesntNeedFunctionStub()); else //ConstantPoolIndex ResultPtr = @@ -557,25 +552,26 @@ void JITEmitter::finishFunction(MachineFunction &F) { } } - TheJIT->getJITInfo().relocate(CurBlock, &Relocations[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 = getJITResolver(this).getGOTIndexForAddr((void*)CurBlock); - if (((void**)MemMgr.getGOTBase())[idx] != (void*)CurBlock) { - DEBUG(std::cerr << "GOT was out of date for " << (void*)CurBlock + unsigned idx = getJITResolver(this).getGOTIndexForAddr((void*)BufferBegin); + if (((void**)MemMgr.getGOTBase())[idx] != (void*)BufferBegin) { + DEBUG(std::cerr << "GOT was out of date for " << (void*)BufferBegin << " pointing at " << ((void**)MemMgr.getGOTBase())[idx] << "\n"); - ((void**)MemMgr.getGOTBase())[idx] = (void*)CurBlock; + ((void**)MemMgr.getGOTBase())[idx] = (void*)BufferBegin; } } - DEBUG(std::cerr << "JIT: Finished CodeGen of [" << (void*)CurBlock + DEBUG(std::cerr << "JIT: Finished CodeGen of [" << (void*)BufferBegin << "] Function: " << F.getFunction()->getName() - << ": " << CurByte-CurBlock << " bytes of text, " + << ": " << getCurrentPCOffset() << " bytes of text, " << Relocations.size() << " relocations\n"); Relocations.clear(); + return false; } void JITEmitter::emitConstantPool(MachineConstantPool *MCP) { @@ -648,26 +644,20 @@ void JITEmitter::emitJumpTableInfo(MachineJumpTableInfo *MJTI, } void JITEmitter::startFunctionStub(unsigned StubSize) { - SavedCurBlock = CurBlock; SavedCurByte = CurByte; - CurByte = CurBlock = MemMgr.allocateStub(StubSize); + SavedBufferBegin = BufferBegin; + SavedBufferEnd = BufferEnd; + SavedCurBufferPtr = CurBufferPtr; + + BufferBegin = CurBufferPtr = MemMgr.allocateStub(StubSize); + BufferEnd = BufferBegin+StubSize+1; } void *JITEmitter::finishFunctionStub(const Function *F) { - NumBytes += CurByte-CurBlock; - std::swap(CurBlock, SavedCurBlock); - CurByte = SavedCurByte; - return SavedCurBlock; -} - -void JITEmitter::emitByte(unsigned char B) { - *CurByte++ = B; // Write the byte to memory -} - -void JITEmitter::emitWord(unsigned W) { - // This won't work if the endianness of the host and target don't agree! (For - // a JIT this can't happen though. :) - *(unsigned*)CurByte = W; - CurByte += sizeof(unsigned); + NumBytes += getCurrentPCOffset(); + std::swap(SavedBufferBegin, BufferBegin); + BufferEnd = SavedBufferEnd; + CurBufferPtr = SavedCurBufferPtr; + return SavedBufferBegin; } // getConstantPoolEntryAddress - Return the address of the 'ConstantNum' entry @@ -702,17 +692,6 @@ unsigned char* JITEmitter::allocateGlobal(unsigned size, unsigned alignment) return MemMgr.allocateGlobal(size, alignment); } -// getCurrentPCValue - This returns the address that the next emitted byte -// will be output to. -// -uint64_t JITEmitter::getCurrentPCValue() { - return (intptr_t)CurByte; -} - -uint64_t JITEmitter::getCurrentPCOffset() { - return (intptr_t)CurByte-(intptr_t)CurBlock; -} - // 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 diff --git a/lib/Target/Alpha/AlphaCodeEmitter.cpp b/lib/Target/Alpha/AlphaCodeEmitter.cpp index f5d517fadd4..dfb7820cae8 100644 --- a/lib/Target/Alpha/AlphaCodeEmitter.cpp +++ b/lib/Target/Alpha/AlphaCodeEmitter.cpp @@ -80,11 +80,15 @@ FunctionPass *llvm::createAlphaCodeEmitterPass(MachineCodeEmitter &MCE) { bool AlphaCodeEmitter::runOnMachineFunction(MachineFunction &MF) { II = ((AlphaTargetMachine&)MF.getTarget()).getInstrInfo(); - MCE.startFunction(MF); - MCE.emitConstantPool(MF.getConstantPool()); - for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) - emitBasicBlock(*I); - MCE.finishFunction(MF); + do { + BBRefs.clear(); + BasicBlockAddrs.clear(); + + MCE.startFunction(MF); + MCE.emitConstantPool(MF.getConstantPool()); + for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) + emitBasicBlock(*I); + } while (MCE.finishFunction(MF)); // Resolve all forward branches now... for (unsigned i = 0, e = BBRefs.size(); i != e; ++i) { diff --git a/lib/Target/PowerPC/PPCCodeEmitter.cpp b/lib/Target/PowerPC/PPCCodeEmitter.cpp index c7f2acbd77c..1b305f4b243 100644 --- a/lib/Target/PowerPC/PPCCodeEmitter.cpp +++ b/lib/Target/PowerPC/PPCCodeEmitter.cpp @@ -89,13 +89,17 @@ bool PPCCodeEmitter::runOnMachineFunction(MachineFunction &MF) { assert((MF.getTarget().getRelocationModel() != Reloc::Default || MF.getTarget().getRelocationModel() != Reloc::Static) && "JIT relocation model must be set to static or default!"); - MCE.startFunction(MF); - MCE.emitConstantPool(MF.getConstantPool()); - MCE.initJumpTableInfo(MF.getJumpTableInfo()); - for (MachineFunction::iterator BB = MF.begin(), E = MF.end(); BB != E; ++BB) - emitBasicBlock(*BB); - MCE.emitJumpTableInfo(MF.getJumpTableInfo(), BBLocations); - MCE.finishFunction(MF); + do { + BBRefs.clear(); + BBLocations.clear(); + + MCE.startFunction(MF); + MCE.emitConstantPool(MF.getConstantPool()); + MCE.initJumpTableInfo(MF.getJumpTableInfo()); + for (MachineFunction::iterator BB = MF.begin(), E = MF.end(); BB != E; ++BB) + emitBasicBlock(*BB); + MCE.emitJumpTableInfo(MF.getJumpTableInfo(), BBLocations); + } while (MCE.finishFunction(MF)); // Resolve branches to BasicBlocks for the entire function for (unsigned i = 0, e = BBRefs.size(); i != e; ++i) { diff --git a/lib/Target/X86/X86CodeEmitter.cpp b/lib/Target/X86/X86CodeEmitter.cpp index 75bc6ce1e33..a278fd548b5 100644 --- a/lib/Target/X86/X86CodeEmitter.cpp +++ b/lib/Target/X86/X86CodeEmitter.cpp @@ -81,13 +81,17 @@ bool Emitter::runOnMachineFunction(MachineFunction &MF) { "JIT relocation model must be set to static or default!"); II = ((X86TargetMachine&)MF.getTarget()).getInstrInfo(); - MCE.startFunction(MF); - MCE.emitConstantPool(MF.getConstantPool()); - MCE.initJumpTableInfo(MF.getJumpTableInfo()); - for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) - emitBasicBlock(*I); - MCE.emitJumpTableInfo(MF.getJumpTableInfo(), BasicBlockAddrs); - MCE.finishFunction(MF); + do { + BBRefs.clear(); + BasicBlockAddrs.clear(); + + MCE.startFunction(MF); + MCE.emitConstantPool(MF.getConstantPool()); + MCE.initJumpTableInfo(MF.getJumpTableInfo()); + for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) + emitBasicBlock(*I); + MCE.emitJumpTableInfo(MF.getJumpTableInfo(), BasicBlockAddrs); + } while (MCE.finishFunction(MF)); // Resolve all forward branches now. for (unsigned i = 0, e = BBRefs.size(); i != e; ++i) { -- 2.34.1