//===-- Emitter.cpp - Write machine code to executable memory -------------===//
+//
+// 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 a MachineCodeEmitter object that is used by Jello to write
// machine code to memory and remember where relocatable values lie.
//
//===----------------------------------------------------------------------===//
-#include "VM.h"
+#define DEBUG_TYPE "jit"
+#ifndef _POSIX_MAPPED_FILES
+#define _POSIX_MAPPED_FILES
+#endif
+#include "JIT.h"
+#include "llvm/Constant.h"
+#include "llvm/Module.h"
#include "llvm/CodeGen/MachineCodeEmitter.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/Target/TargetData.h"
-#include "llvm/Function.h"
+#include "Support/Debug.h"
#include "Support/Statistic.h"
-
-static VM *TheVM = 0;
+#include "Config/unistd.h"
+#include "Config/sys/mman.h"
+using namespace llvm;
namespace {
- Statistic<> NumBytes("jello", "Number of bytes of machine code compiled");
+ Statistic<> NumBytes("jit", "Number of bytes of machine code compiled");
+ JIT *TheJIT = 0;
+
+ /// JITMemoryManager - Manage memory for the JIT code generation in a logical,
+ /// sane way. This splits a large block of MAP_NORESERVE'd memory into two
+ /// sections, one for function stubs, one for the functions themselves. We
+ /// have to do this because we may need to emit a function stub while in the
+ /// middle of emitting a function, and we don't know how large the function we
+ /// are emitting is. This never bothers to release the memory, because when
+ /// we are ready to destroy the JIT, the program exits.
+ class JITMemoryManager {
+ unsigned char *MemBase; // Base of block of memory, start of stub mem
+ unsigned char *FunctionBase; // Start of the function body area
+ unsigned char *CurStubPtr, *CurFunctionPtr;
+ public:
+ JITMemoryManager();
+
+ inline unsigned char *allocateStub(unsigned StubSize);
+ inline unsigned char *startFunctionBody();
+ inline void endFunctionBody(unsigned char *FunctionEnd);
+ };
+}
+
+// getMemory - Return a pointer to the specified number of bytes, which is
+// mapped as executable readable and writable.
+static void *getMemory(unsigned NumBytes) {
+ if (NumBytes == 0) return 0;
+ static const long pageSize = sysconf(_SC_PAGESIZE);
+ unsigned NumPages = (NumBytes+pageSize-1)/pageSize;
+
+#if defined(i386) || defined(__i386__) || defined(__x86__)
+ /* Linux and *BSD tend to have these flags named differently. */
+#if defined(MAP_ANON) && !defined(MAP_ANONYMOUS)
+# define MAP_ANONYMOUS MAP_ANON
+#endif /* defined(MAP_ANON) && !defined(MAP_ANONYMOUS) */
+#elif defined(sparc) || defined(__sparc__) || defined(__sparcv9)
+/* nothing */
+#else
+ std::cerr << "This architecture is not supported by the JIT!\n";
+ abort();
+#endif
+
+#if defined(__linux__)
+#define fd 0
+#else
+#define fd -1
+#endif
+
+ unsigned mmapFlags = MAP_PRIVATE|MAP_ANONYMOUS;
+#ifdef MAP_NORESERVE
+ mmapFlags |= MAP_NORESERVE;
+#endif
+
+ void *pa = mmap(0, pageSize*NumPages, PROT_READ|PROT_WRITE|PROT_EXEC,
+ mmapFlags, fd, 0);
+ if (pa == MAP_FAILED) {
+ perror("mmap");
+ abort();
+ }
+ return pa;
+}
+
+JITMemoryManager::JITMemoryManager() {
+ // Allocate a 16M block of memory...
+ MemBase = (unsigned char*)getMemory(16 << 20);
+ FunctionBase = MemBase + 512*1024; // Use 512k for stubs
+
+ // Allocate stubs backwards from the function base, allocate functions forward
+ // from the function base.
+ CurStubPtr = CurFunctionPtr = FunctionBase;
+}
+
+unsigned char *JITMemoryManager::allocateStub(unsigned StubSize) {
+ CurStubPtr -= StubSize;
+ if (CurStubPtr < MemBase) {
+ std::cerr << "JIT ran out of memory for function stubs!\n";
+ abort();
+ }
+ return CurStubPtr;
+}
+
+unsigned char *JITMemoryManager::startFunctionBody() {
+ // Round up to an even multiple of 4 bytes, this should eventually be target
+ // specific.
+ return (unsigned char*)(((intptr_t)CurFunctionPtr + 3) & ~3);
+}
+
+void JITMemoryManager::endFunctionBody(unsigned char *FunctionEnd) {
+ assert(FunctionEnd > CurFunctionPtr);
+ CurFunctionPtr = FunctionEnd;
+}
+
+
+namespace {
+ /// Emitter - The JIT implementation of the MachineCodeEmitter, which is used
+ /// to output functions to memory for execution.
class Emitter : public MachineCodeEmitter {
+ JITMemoryManager MemMgr;
+
// CurBlock - The start of the current block of memory. CurByte - The
// current byte being emitted to.
unsigned char *CurBlock, *CurByte;
// constant pool.
std::vector<void*> ConstantPoolAddresses;
public:
- Emitter(VM &vm) { TheVM = &vm; }
+ Emitter(JIT &jit) { TheJIT = &jit; }
virtual void startFunction(MachineFunction &F);
virtual void finishFunction(MachineFunction &F);
};
}
-MachineCodeEmitter *VM::createX86Emitter(VM &V) {
- return new Emitter(V);
-}
-
-
-#define _POSIX_MAPPED_FILES
-#include <unistd.h>
-#include <sys/mman.h>
-
-// FIXME: This should be rewritten to support a real memory manager for
-// executable memory pages!
-static void *getMemory(unsigned NumPages) {
- return mmap(0, 4096*NumPages, PROT_READ|PROT_WRITE|PROT_EXEC,
- MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
+MachineCodeEmitter *JIT::createEmitter(JIT &jit) {
+ return new Emitter(jit);
}
-
void Emitter::startFunction(MachineFunction &F) {
- CurBlock = (unsigned char *)getMemory(16);
- CurByte = CurBlock; // Start writing at the beginning of the fn.
- TheVM->addGlobalMapping(F.getFunction(), CurBlock);
+ CurByte = CurBlock = MemMgr.startFunctionBody();
+ TheJIT->addGlobalMapping(F.getFunction(), CurBlock);
}
void Emitter::finishFunction(MachineFunction &F) {
+ MemMgr.endFunctionBody(CurByte);
ConstantPoolAddresses.clear();
NumBytes += CurByte-CurBlock;
- DEBUG(std::cerr << "Finished CodeGen of [0x" << std::hex
- << (unsigned)(intptr_t)CurBlock
- << std::dec << "] Function: " << F.getFunction()->getName()
+ DEBUG(std::cerr << "Finished CodeGen of [" << (void*)CurBlock
+ << "] Function: " << F.getFunction()->getName()
<< ": " << CurByte-CurBlock << " bytes of text\n");
}
void Emitter::emitConstantPool(MachineConstantPool *MCP) {
const std::vector<Constant*> &Constants = MCP->getConstants();
+ if (Constants.empty()) return;
+
+ std::vector<unsigned> ConstantOffset;
+ ConstantOffset.reserve(Constants.size());
+
+ // Calculate how much space we will need for all the constants, and the offset
+ // each one will live in.
+ unsigned TotalSize = 0;
for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
- // For now we just allocate some memory on the heap, this can be
- // dramatically improved.
- const Type *Ty = ((Value*)Constants[i])->getType();
- void *Addr = malloc(TheVM->getTargetData().getTypeSize(Ty));
- TheVM->InitializeMemory(Constants[i], Addr);
+ const Type *Ty = Constants[i]->getType();
+ unsigned Size = TheJIT->getTargetData().getTypeSize(Ty);
+ unsigned Alignment = TheJIT->getTargetData().getTypeAlignment(Ty);
+ // Make sure to take into account the alignment requirements of the type.
+ TotalSize = (TotalSize + Alignment-1) & ~(Alignment-1);
+
+ // Remember the offset this element lives at.
+ ConstantOffset.push_back(TotalSize);
+ TotalSize += Size; // Reserve space for the constant.
+ }
+
+ // Now that we know how much memory to allocate, do so.
+ char *Pool = new char[TotalSize];
+
+ // Actually output all of the constants, and remember their addresses.
+ for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
+ void *Addr = Pool + ConstantOffset[i];
+ TheJIT->InitializeMemory(Constants[i], Addr);
ConstantPoolAddresses.push_back(Addr);
}
}
void Emitter::startFunctionStub(const Function &F, unsigned StubSize) {
SavedCurBlock = CurBlock; SavedCurByte = CurByte;
- // FIXME: this is a huge waste of memory.
- CurBlock = (unsigned char *)getMemory((StubSize+4095)/4096);
- CurByte = CurBlock; // Start writing at the beginning of the fn.
+ CurByte = CurBlock = MemMgr.allocateStub(StubSize);
}
void *Emitter::finishFunctionStub(const Function &F) {
}
void Emitter::emitWord(unsigned W) {
- // FIXME: This won't work if the endianness of the host and target don't
- // agree! (For a JIT this can't happen though. :)
+ // 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);
}
-
uint64_t Emitter::getGlobalValueAddress(GlobalValue *V) {
// Try looking up the function to see if it is already compiled, if not return
// 0.
- return (intptr_t)TheVM->getPointerToGlobalIfAvailable(V);
+ if (isa<Function>(V))
+ return (intptr_t)TheJIT->getPointerToGlobalIfAvailable(V);
+ else {
+ return (intptr_t)TheJIT->getOrEmitGlobalVariable(cast<GlobalVariable>(V));
+ }
}
uint64_t Emitter::getGlobalValueAddress(const std::string &Name) {
- return (intptr_t)TheVM->getPointerToNamedFunction(Name);
+ return (intptr_t)TheJIT->getPointerToNamedFunction(Name);
}
// getConstantPoolEntryAddress - Return the address of the 'ConstantNum' entry
}
uint64_t Emitter::forceCompilationOf(Function *F) {
- return (intptr_t)TheVM->getPointerToFunction(F);
+ return (intptr_t)TheJIT->getPointerToFunction(F);
}
+// 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) {
+ Module &M = TheJIT->getModule();
+ if (Function *F = M.getNamedFunction(Name))
+ return TheJIT->getPointerToFunction(F);
+ return TheJIT->getPointerToNamedFunction(Name);
+ }
+}
projects / oota-llvm.git / blobdiff