1 files changed, 74 insertions, 0 deletions
diff --git a/llvm/tools/jello/Emitter.cpp b/llvm/tools/jello/Emitter.cpp
new file mode 100644
index 00000000000..89695ad2b4f
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+++ b/llvm/tools/jello/Emitter.cpp
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+//===-- 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"
+
+namespace {
+  class Emitter : public MachineCodeEmitter {
+    VM &TheVM;
+
+    unsigned char *CurBlock;
+    unsigned char *CurByte;
+  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);
+  };
+}
+
+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.
+}
+
+#include <iostream>
+#include "llvm/Function.h"
+
+void Emitter::finishFunction(MachineFunction &F) {
+  std::cerr << "Finished Code Generation of Function: "
+            << F.getFunction()->getName() << ": " << CurByte-CurBlock
+            << " bytes of text\n";
+  TheVM.addGlobalMapping(F.getFunction(), CurBlock);
+}
+
+
+
+void Emitter::emitByte(unsigned char B) {
+  *CurByte++ = B;   // Write the byte to memory
+}
+
+
+// emitPCRelativeDisp - 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.
+//
+void Emitter::emitPCRelativeDisp(Value *V) {
+  unsigned ZeroAddr = -(unsigned)CurByte;  // Calculate displacement to null
+  *(unsigned*)CurByte = ZeroAddr;   // 4 byte offset
+  CurByte += 4;
+}