Initial checkin of new LLI with JIT compiler
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5126 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/ExecutionEngine/JIT/JITEmitter.cpp b/lib/ExecutionEngine/JIT/JITEmitter.cpp
new file mode 100644
index 0000000..253a229
--- /dev/null
+++ b/lib/ExecutionEngine/JIT/JITEmitter.cpp
@@ -0,0 +1,107 @@
+//===-- Emitter.cpp - Write machine code to executable memory -------------===//
+//
+// 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"
+#include "llvm/CodeGen/MachineCodeEmitter.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/Function.h"
+#include "Support/Statistic.h"
+
+namespace {
+ Statistic<> NumBytes("jello", "Number of bytes of machine code compiled");
+
+ class Emitter : public MachineCodeEmitter {
+ VM &TheVM;
+
+ unsigned char *CurBlock;
+ unsigned char *CurByte;
+
+ std::vector<std::pair<BasicBlock*, unsigned *> > BBRefs;
+ std::map<BasicBlock*, unsigned> BBLocations;
+ public:
+ Emitter(VM &vm) : TheVM(vm) {}
+
+ virtual void startFunction(MachineFunction &F);
+ virtual void finishFunction(MachineFunction &F);
+ virtual void startBasicBlock(MachineBasicBlock &BB);
+ virtual void emitByte(unsigned char B);
+ virtual void emitPCRelativeDisp(Value *V);
+ virtual void emitGlobalAddress(GlobalValue *V);
+ };
+}
+
+MachineCodeEmitter *VM::createEmitter(VM &V) {
+ return new Emitter(V);
+}
+
+
+#define _POSIX_MAPPED_FILES
+#include <unistd.h>
+#include <sys/mman.h>
+
+static void *getMemory() {
+ return mmap(0, 4096*2, PROT_READ|PROT_WRITE|PROT_EXEC,
+ MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
+}
+
+
+void Emitter::startFunction(MachineFunction &F) {
+ CurBlock = (unsigned char *)getMemory();
+ CurByte = CurBlock; // Start writing at the beginning of the fn.
+ TheVM.addGlobalMapping(F.getFunction(), CurBlock);
+}
+
+void Emitter::finishFunction(MachineFunction &F) {
+ for (unsigned i = 0, e = BBRefs.size(); i != e; ++i) {
+ unsigned Location = BBLocations[BBRefs[i].first];
+ unsigned *Ref = BBRefs[i].second;
+ *Ref = Location-(unsigned)Ref-4;
+ }
+ BBRefs.clear();
+ BBLocations.clear();
+
+ NumBytes += CurByte-CurBlock;
+
+ DEBUG(std::cerr << "Finished CodeGen of [" << std::hex << (unsigned)CurBlock
+ << std::dec << "] Function: " << F.getFunction()->getName()
+ << ": " << CurByte-CurBlock << " bytes of text\n");
+}
+
+void Emitter::startBasicBlock(MachineBasicBlock &BB) {
+ BBLocations[BB.getBasicBlock()] = (unsigned)CurByte;
+}
+
+
+void Emitter::emitByte(unsigned char B) {
+ *CurByte++ = B; // Write the byte to memory
+}
+
+
+// emitPCRelativeDisp - For functions, just output a displacement that will
+// cause a reference to the zero page, which will cause a seg-fault, causing
+// things to get resolved on demand. Keep track of these markers.
+//
+// For basic block references, keep track of where the references are so they
+// may be patched up when the basic block is defined.
+//
+void Emitter::emitPCRelativeDisp(Value *V) {
+ if (Function *F = dyn_cast<Function>(V)) {
+ TheVM.addFunctionRef(CurByte, F);
+ unsigned ZeroAddr = -(unsigned)CurByte-4; // Calculate displacement to null
+ *(unsigned*)CurByte = ZeroAddr; // 4 byte offset
+ CurByte += 4;
+ } else {
+ BasicBlock *BB = cast<BasicBlock>(V); // Keep track of reference...
+ BBRefs.push_back(std::make_pair(BB, (unsigned*)CurByte));
+ CurByte += 4;
+ }
+}
+
+void Emitter::emitGlobalAddress(GlobalValue *V) {
+ *(void**)CurByte = TheVM.getPointerToGlobal(V);
+ CurByte += 4;
+}