It's not necessary to do rounding for alloca operations when the requested
alignment is equal to the stack alignment.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40004 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/ExecutionEngine/Interpreter/Interpreter.h b/lib/ExecutionEngine/Interpreter/Interpreter.h
new file mode 100644
index 0000000..3238850
--- /dev/null
+++ b/lib/ExecutionEngine/Interpreter/Interpreter.h
@@ -0,0 +1,241 @@
+//===-- Interpreter.h ------------------------------------------*- C++ -*--===//
+//
+//                     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 header file defines the interpreter structure
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLI_INTERPRETER_H
+#define LLI_INTERPRETER_H
+
+#include "llvm/Function.h"
+#include "llvm/ExecutionEngine/ExecutionEngine.h"
+#include "llvm/ExecutionEngine/GenericValue.h"
+#include "llvm/ADT/APInt.h"
+#include "llvm/Support/InstVisitor.h"
+#include "llvm/Support/CallSite.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Support/DataTypes.h"
+
+namespace llvm {
+
+class IntrinsicLowering;
+struct FunctionInfo;
+template<typename T> class generic_gep_type_iterator;
+class ConstantExpr;
+typedef generic_gep_type_iterator<User::const_op_iterator> gep_type_iterator;
+
+
+// AllocaHolder - Object to track all of the blocks of memory allocated by
+// alloca.  When the function returns, this object is popped off the execution
+// stack, which causes the dtor to be run, which frees all the alloca'd memory.
+//
+class AllocaHolder {
+  friend class AllocaHolderHandle;
+  std::vector<void*> Allocations;
+  unsigned RefCnt;
+public:
+  AllocaHolder() : RefCnt(0) {}
+  void add(void *mem) { Allocations.push_back(mem); }
+  ~AllocaHolder() {
+    for (unsigned i = 0; i < Allocations.size(); ++i)
+      free(Allocations[i]);
+  }
+};
+
+// AllocaHolderHandle gives AllocaHolder value semantics so we can stick it into
+// a vector...
+//
+class AllocaHolderHandle {
+  AllocaHolder *H;
+public:
+  AllocaHolderHandle() : H(new AllocaHolder()) { H->RefCnt++; }
+  AllocaHolderHandle(const AllocaHolderHandle &AH) : H(AH.H) { H->RefCnt++; }
+  ~AllocaHolderHandle() { if (--H->RefCnt == 0) delete H; }
+
+  void add(void *mem) { H->add(mem); }
+};
+
+typedef std::vector<GenericValue> ValuePlaneTy;
+
+// ExecutionContext struct - This struct represents one stack frame currently
+// executing.
+//
+struct ExecutionContext {
+  Function             *CurFunction;// The currently executing function
+  BasicBlock           *CurBB;      // The currently executing BB
+  BasicBlock::iterator  CurInst;    // The next instruction to execute
+  std::map<Value *, GenericValue> Values; // LLVM values used in this invocation
+  std::vector<GenericValue>  VarArgs; // Values passed through an ellipsis
+  CallSite             Caller;     // Holds the call that called subframes.
+                                   // NULL if main func or debugger invoked fn
+  AllocaHolderHandle    Allocas;    // Track memory allocated by alloca
+};
+
+// Interpreter - This class represents the entirety of the interpreter.
+//
+class Interpreter : public ExecutionEngine, public InstVisitor<Interpreter> {
+  GenericValue ExitValue;          // The return value of the called function
+  TargetData TD;
+  IntrinsicLowering *IL;
+
+  // The runtime stack of executing code.  The top of the stack is the current
+  // function record.
+  std::vector<ExecutionContext> ECStack;
+
+  // AtExitHandlers - List of functions to call when the program exits,
+  // registered with the atexit() library function.
+  std::vector<Function*> AtExitHandlers;
+
+public:
+  Interpreter(Module *M);
+  ~Interpreter();
+
+  /// runAtExitHandlers - Run any functions registered by the program's calls to
+  /// atexit(3), which we intercept and store in AtExitHandlers.
+  ///
+  void runAtExitHandlers();
+
+  static void Register() {
+    InterpCtor = create;
+  }
+  
+  /// create - Create an interpreter ExecutionEngine. This can never fail.
+  ///
+  static ExecutionEngine *create(ModuleProvider *M, std::string *ErrorStr = 0);
+
+  /// run - Start execution with the specified function and arguments.
+  ///
+  virtual GenericValue runFunction(Function *F,
+                                   const std::vector<GenericValue> &ArgValues);
+
+  /// recompileAndRelinkFunction - For the interpreter, functions are always
+  /// up-to-date.
+  ///
+  virtual void *recompileAndRelinkFunction(Function *F) {
+    return getPointerToFunction(F);
+  }
+
+  /// freeMachineCodeForFunction - The interpreter does not generate any code.
+  ///
+  void freeMachineCodeForFunction(Function *F) { }
+
+  // Methods used to execute code:
+  // Place a call on the stack
+  void callFunction(Function *F, const std::vector<GenericValue> &ArgVals);
+  void run();                // Execute instructions until nothing left to do
+
+  // Opcode Implementations
+  void visitReturnInst(ReturnInst &I);
+  void visitBranchInst(BranchInst &I);
+  void visitSwitchInst(SwitchInst &I);
+
+  void visitBinaryOperator(BinaryOperator &I);
+  void visitICmpInst(ICmpInst &I);
+  void visitFCmpInst(FCmpInst &I);
+  void visitAllocationInst(AllocationInst &I);
+  void visitFreeInst(FreeInst &I);
+  void visitLoadInst(LoadInst &I);
+  void visitStoreInst(StoreInst &I);
+  void visitGetElementPtrInst(GetElementPtrInst &I);
+  void visitPHINode(PHINode &PN) { assert(0 && "PHI nodes already handled!"); }
+  void visitTruncInst(TruncInst &I);
+  void visitZExtInst(ZExtInst &I);
+  void visitSExtInst(SExtInst &I);
+  void visitFPTruncInst(FPTruncInst &I);
+  void visitFPExtInst(FPExtInst &I);
+  void visitUIToFPInst(UIToFPInst &I);
+  void visitSIToFPInst(SIToFPInst &I);
+  void visitFPToUIInst(FPToUIInst &I);
+  void visitFPToSIInst(FPToSIInst &I);
+  void visitPtrToIntInst(PtrToIntInst &I);
+  void visitIntToPtrInst(IntToPtrInst &I);
+  void visitBitCastInst(BitCastInst &I);
+  void visitSelectInst(SelectInst &I);
+
+
+  void visitCallSite(CallSite CS);
+  void visitCallInst(CallInst &I) { visitCallSite (CallSite (&I)); }
+  void visitInvokeInst(InvokeInst &I) { visitCallSite (CallSite (&I)); }
+  void visitUnwindInst(UnwindInst &I);
+  void visitUnreachableInst(UnreachableInst &I);
+
+  void visitShl(BinaryOperator &I);
+  void visitLShr(BinaryOperator &I);
+  void visitAShr(BinaryOperator &I);
+
+  void visitVAArgInst(VAArgInst &I);
+  void visitInstruction(Instruction &I) {
+    cerr << I;
+    assert(0 && "Instruction not interpretable yet!");
+  }
+
+  GenericValue callExternalFunction(Function *F,
+                                    const std::vector<GenericValue> &ArgVals);
+  void exitCalled(GenericValue GV);
+
+  void addAtExitHandler(Function *F) {
+    AtExitHandlers.push_back(F);
+  }
+
+  GenericValue *getFirstVarArg () {
+    return &(ECStack.back ().VarArgs[0]);
+  }
+
+  //FIXME: private:
+public:
+  GenericValue executeGEPOperation(Value *Ptr, gep_type_iterator I,
+                                   gep_type_iterator E, ExecutionContext &SF);
+
+private:  // Helper functions
+  // SwitchToNewBasicBlock - Start execution in a new basic block and run any
+  // PHI nodes in the top of the block.  This is used for intraprocedural
+  // control flow.
+  //
+  void SwitchToNewBasicBlock(BasicBlock *Dest, ExecutionContext &SF);
+
+  void *getPointerToFunction(Function *F) { return (void*)F; }
+
+  void initializeExecutionEngine();
+  void initializeExternalFunctions();
+  GenericValue getConstantExprValue(ConstantExpr *CE, ExecutionContext &SF);
+  GenericValue getOperandValue(Value *V, ExecutionContext &SF);
+  GenericValue executeTruncInst(Value *SrcVal, const Type *DstTy,
+                                ExecutionContext &SF);
+  GenericValue executeSExtInst(Value *SrcVal, const Type *DstTy,
+                               ExecutionContext &SF);
+  GenericValue executeZExtInst(Value *SrcVal, const Type *DstTy,
+                               ExecutionContext &SF);
+  GenericValue executeFPTruncInst(Value *SrcVal, const Type *DstTy,
+                                  ExecutionContext &SF);
+  GenericValue executeFPExtInst(Value *SrcVal, const Type *DstTy,
+                                ExecutionContext &SF);
+  GenericValue executeFPToUIInst(Value *SrcVal, const Type *DstTy,
+                                 ExecutionContext &SF);
+  GenericValue executeFPToSIInst(Value *SrcVal, const Type *DstTy,
+                                 ExecutionContext &SF);
+  GenericValue executeUIToFPInst(Value *SrcVal, const Type *DstTy,
+                                 ExecutionContext &SF);
+  GenericValue executeSIToFPInst(Value *SrcVal, const Type *DstTy,
+                                 ExecutionContext &SF);
+  GenericValue executePtrToIntInst(Value *SrcVal, const Type *DstTy,
+                                   ExecutionContext &SF);
+  GenericValue executeIntToPtrInst(Value *SrcVal, const Type *DstTy,
+                                   ExecutionContext &SF);
+  GenericValue executeBitCastInst(Value *SrcVal, const Type *DstTy,
+                                  ExecutionContext &SF);
+  GenericValue executeCastOperation(Instruction::CastOps opcode, Value *SrcVal, 
+                                    const Type *Ty, ExecutionContext &SF);
+  void popStackAndReturnValueToCaller(const Type *RetTy, GenericValue Result);
+
+};
+
+} // End llvm namespace
+
+#endif