Initial skeleton of Subzero.

src/IceCfg.h

Index: src/IceCfg.h
diff --git a/src/IceCfg.h b/src/IceCfg.h
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+//===- subzero/src/IceCfg.h - Control flow graph ----------------*- C++ -*-===//
+//
+//                        The Subzero Code Generator
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file declares the IceCfg class, which represents the control
+// flow graph and the overall per-function compilation context.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SUBZERO_SRC_ICECFG_H
+#define SUBZERO_SRC_ICECFG_H
+
+#include "IceDefs.h"
+#include "IceTypes.h"
+#include "IceGlobalContext.h"
+
+#include "llvm/ADT/OwningPtr.h"
+#include "llvm/Support/Allocator.h"
+
+namespace Ice {
+
+class IceCfg {
+public:
+  IceCfg(GlobalContext *Ctx);
+  ~IceCfg();
+
+  GlobalContext *getContext() const { return Ctx; }
+
+  // Manage the name and return type of the function being translated.
+  void setFunctionName(const IceString &Name) { FunctionName = Name; }
+  IceString getFunctionName() const { return FunctionName; }
+  void setReturnType(IceType Type) { ReturnType = Type; }
+
+  // Manage the "internal" attribute of the function.
+  void setInternal(bool Internal) { IsInternalLinkage = Internal; }
+  bool getInternal() const { return IsInternalLinkage; }
+
+  // Translation error flagging.  If support for some construct is
+  // known to be missing, instead of an assertion failure, setError()
+  // should be called and the error should be propagated back up.
+  // This way, we can gracefully fail to translate and let a fallback
+  // translator handle the function.
+  void setError(const IceString &Message);
+  bool hasError() const { return HasError; }
+  IceString getError() const { return ErrorMessage; }
+
+  // Manage nodes (a.k.a. basic blocks, CfgNodes).
+  void setEntryNode(CfgNode *EntryNode) { Entry = EntryNode; }
+  CfgNode *getEntryNode() const { return Entry; }
+  // Create a node and append it to the end of the linearized list.
+  CfgNode *makeNode(const IceString &Name = "");
+  IceSize_t getNumNodes() const { return Nodes.size(); }
+  const NodeList &getNodes() const { return Nodes; }
+
+  // Manage instruction numbering.
+  int newInstNumber() { return NextInstNumber++; }
+
+  // Manage Variables.
+  Variable *makeVariable(IceType Type, const CfgNode *Node,
+                         const IceString &Name = "");
+  IceSize_t getNumVariables() const { return Variables.size(); }
+  const VarList &getVariables() const { return Variables; }
+
+  // Manage arguments to the function.
+  void addArg(Variable *Arg);
+  const VarList &getArgs() const { return Args; }
+
+  // After the CFG is fully constructed, iterate over the nodes and
+  // compute the predecessor edges, in the form of
+  // CfgNode::InEdges[].
+  void computePredecessors();
+
+  // Manage the CurrentNode field, which is used for validating the
+  // Variable::DefNode field during dumping/emitting.
+  void setCurrentNode(const CfgNode *Node) { CurrentNode = Node; }
+  const CfgNode *getCurrentNode() const { return CurrentNode; }
+
+  void dump();
+
+  // Allocate data of type T using the per-Cfg allocator.
+  template <typename T> T *allocate() { return Allocator.Allocate<T>(); }
+
+  // Allocate an instruction of type T using the per-Cfg instruction allocator.
+  template <typename T> T *allocateInst() { return Allocator.Allocate<T>(); }
+
+  // Allocate an array of data of type T using the per-Cfg allocator.
+  template <typename T> T *allocateArrayOf(size_t NumElems) {
+    return Allocator.Allocate<T>(NumElems);
+  }
+
+private:
+  // TODO: for now, everything is allocated from the same allocator. In the
+  // future we may want to split this to several allocators, for example in
+  // order to use a "Recycler" to preserve memory. If we keep all allocation
+  // requests from the Cfg exposed via methods, we can always switch the
+  // implementation over at a later point.
+  llvm::BumpPtrAllocator Allocator;
+
+  GlobalContext *Ctx;
+  IceString FunctionName;
+  IceType ReturnType;
+  bool IsInternalLinkage;
+  bool HasError;
+  IceString ErrorMessage;
+  CfgNode *Entry; // entry basic block
+  NodeList Nodes; // linearized node list; Entry should be first
+  int NextInstNumber;
+  VarList Variables;
+  VarList Args; // subset of Variables, in argument order
+
+  // CurrentNode is maintained during dumping/emitting just for
+  // validating Variable::DefNode.  Normally, a traversal over
+  // CfgNodes maintains this, but before global operations like
+  // register allocation, setCurrentNode(NULL) should be called to
+  // avoid spurious validation failures.
+  const CfgNode *CurrentNode;
+
+  IceCfg(const IceCfg &) LLVM_DELETED_FUNCTION;
+  IceCfg &operator=(const IceCfg &) LLVM_DELETED_FUNCTION;
+};
+
+} // end of namespace Ice
+
+#endif // SUBZERO_SRC_ICECFG_H