//
//===----------------------------------------------------------------------===//
+#define DEBUG_TYPE "jit"
+#ifndef _POSIX_MAPPED_FILES
+#define _POSIX_MAPPED_FILES
+#endif
#include "VM.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 "llvm/Module.h"
+#include "Support/Debug.h"
#include "Support/Statistic.h"
-
-static VM *TheVM = 0;
+#include "Config/unistd.h"
+#include "Config/sys/mman.h"
namespace {
- Statistic<> NumBytes("jello", "Number of bytes of machine code compiled");
+ Statistic<> NumBytes("jit", "Number of bytes of machine code compiled");
+ VM *TheVM = 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;
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) {
-#if defined(i386) || defined(__i386__) || defined(__x86__)
- static const int fd = 0;
-#elif defined(sparc) || defined(__sparc__) || defined(__sparcv9)
- static const int fd = -1;
-#else
- // This is an unsupported architecture.
- static const int fd = 0;
-#endif
-
- void *pa;
- if (NumPages == 0) return 0;
- static const long pageSize = sysconf (_SC_PAGESIZE);
- pa = mmap(0, pageSize*NumPages, PROT_READ|PROT_WRITE|PROT_EXEC,
- MAP_PRIVATE|MAP_ANONYMOUS, fd, 0);
- if (pa == MAP_FAILED) {
- perror("mmap");
- abort();
- }
- return pa;
-}
-
-
void Emitter::startFunction(MachineFunction &F) {
- CurBlock = (unsigned char *)getMemory(16);
- CurByte = CurBlock; // Start writing at the beginning of the fn.
+ CurByte = CurBlock = MemMgr.startFunctionBody();
TheVM->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::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->getPointerToFunction(F);
}
+// getPointerToNamedFunction - This function is used as a global wrapper to
+// VM::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 = TheVM->getModule();
+ if (Function *F = M.getNamedFunction(Name))
+ return TheVM->getPointerToFunction(F);
+ return TheVM->getPointerToNamedFunction(Name);
+ }
+}
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