Add a framework for intercepting system calls


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@6190 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/ExecutionEngine/JIT/VM.cpp b/lib/ExecutionEngine/JIT/VM.cpp
index 6fd366e..c6748fa 100644
--- a/lib/ExecutionEngine/JIT/VM.cpp
+++ b/lib/ExecutionEngine/JIT/VM.cpp
@@ -1,4 +1,4 @@
-//===-- jello.cpp - LLVM Just in Time Compiler ----------------------------===//
+//===-- VM.cpp - LLVM Just in Time Compiler -------------------------------===//
 //
 // This tool implements a just-in-time compiler for LLVM, allowing direct
 // execution of LLVM bytecode in an efficient manner.
@@ -9,8 +9,6 @@
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/CodeGen/MachineCodeEmitter.h"
 #include "llvm/Function.h"
-#include <dlfcn.h>    // dlsym access
-
 
 VM::~VM() {
   delete MCE;
@@ -50,27 +48,10 @@
 }
 
 const std::string &VM::getFunctionReferencedName(void *RefAddr) {
+  assert(FunctionRefs[RefAddr] && "Function address unknown!");
   return FunctionRefs[RefAddr]->getName();
 }
 
-static void NoopFn() {}
-
-/// getPointerToNamedFunction - This method returns the address of the specified
-/// function by using the dlsym function call.  As such it is only useful for
-/// resolving library symbols, not code generated symbols.
-///
-void *VM::getPointerToNamedFunction(const std::string &Name) {
-  // If it's an external function, look it up in the process image...
-  void *Ptr = dlsym(0, Name.c_str());
-  if (Ptr == 0) {
-    std::cerr << "WARNING: Cannot resolve fn '" << Name
-	      << "' using a dummy noop function instead!\n";
-    Ptr = (void*)NoopFn;
-  }
-  
-  return Ptr;
-}
-
 /// getPointerToFunction - This method is used to get the address of the
 /// specified function, compiling it if neccesary.
 ///