Initial skeleton of Subzero.

src/IceCfg.h

+//===- 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 "llvm/Support/Allocator.h"
+
+class IceCfg {
+public:
+  IceCfg();
+  ~IceCfg();
+
+  // Manage the name and return type of the function being translated.
+  void setName(const IceString &FunctionName) { Name = FunctionName; }
+  IceString getName() const { return Name; }
+  void setReturnType(IceType ReturnType) { Type = ReturnType; }

[JF, 2014/04/04 04:05:26]

The return type of what? The function associated with the CFG?

[Jim Stichnoth, 2014/04/06 02:16:09]

Yes, this is in a comment 3 lines above. :)

+
+  // When emitting assembly, we allow a string to be prepended to
+  // names of translated functions.  This makes it easier to create an
+  // execution test against a reference translator like llc, with both
+  // translators using the same bitcode as input.
+  void setTestPrefix(const IceString &Prefix) { TestPrefix = Prefix; }
+  IceString getTestPrefix() const { return TestPrefix; }
+  IceString mangleName(const IceString &Name) const {
+    return getTestPrefix() + Name;
+  }
+
+  // Manage the "internal" attribute of the function.
+  void setInternal(bool Internal) { IsInternal = Internal; }
+  bool getInternal() const { return IsInternal; }
+
+  // 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, IceCfgNodes).
+  void setEntryNode(IceCfgNode *EntryNode) { Entry = EntryNode; }
+  IceCfgNode *getEntryNode() const { return Entry; }
+  // Create a node and append it to the end of the linearized list.
+  IceCfgNode *makeNode(const IceString &Name = "");
+  uint32_t getNumNodes() const { return Nodes.size(); }
+  const IceNodeList &getNodes() const { return Nodes; }
+
+  // Manage instruction numbering.
+  int newInstNumber() { return NextInstNumber++; }
+
+  // Manage IceVariables.
+  IceVariable *makeVariable(IceType Type, const IceCfgNode *Node,
+                            const IceString &Name = "");
+  uint32_t getNumVariables() const { return Variables.size(); }
+  const IceVarList &getVariables() const { return Variables; }
+
+  // Manage arguments to the function.
+  void addArg(IceVariable *Arg);
+  const IceVarList &getArgs() const { return Args; }
+
+  // Manage IceConstants.
+  // getConstant*() functions are not const because they might add
+  // something to the constant pool.
+  IceConstant *getConstantInt(IceType Type, uint64_t ConstantInt64);
+  IceConstant *getConstantFloat(float Value);
+  IceConstant *getConstantDouble(double Value);
+  // Returns a symbolic constant.  Handle is currently unused but is
+  // reserved to hold something LLVM-specific to facilitate linking.
+  IceConstant *getConstantSym(IceType Type, const void *Handle, int64_t Offset,
+                              const IceString &Name = "",
+                              bool SuppressMangling = false);
+
+  void registerEdges();
+  void dump() const;
+
+  // Allocate data of type T using the per-Cfg instruction 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);
+  }
+
+  mutable IceOstream Str;

[JF, 2014/04/04 04:05:26]

This would be nicer in a separate context object or something passed in to
IceCfg at construction time.

Also, mutable, ew.

[Jim Stichnoth, 2014/04/06 02:16:09]

If you don't mind, I'd love to defer this cleanup after the first round of CLs,
to include:
* Separate ostreams for dumping versus code emission
* Separate allocators for per-function versus global (e.g. global constant pool)
* Other issues that I haven't yet dealt with such as global initializers

[Jim Stichnoth, 2014/04/09 05:34:27]

Never mind the deferral request.  The latest patchset provides this global
context, which includes the output streams.  It also includes a global allocator
from which constants are allocated and pooled.

+
+private:

[JF, 2014/04/04 04:05:26]

Disable copy/assign:
 
http://llvm.org/docs/CodingStandards.html#use-llvm-deleted-function-to-mark-u...

Unless you actually want them, in which case they should be explicit.

Same for other classes.

[Jim Stichnoth, 2014/04/06 02:16:09]

Done.

+  // 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;
+
+  IceString Name;       // function name
+  IceString TestPrefix; // prepended to all symbol names, for testing
+  IceType Type;         // return type
+  bool IsInternal;      // internal linkage
+  bool HasError;
+  IceString ErrorMessage;
+  IceCfgNode *Entry; // entry basic block
+  IceNodeList Nodes; // linearized node list; Entry should be first
+  int NextInstNumber;
+  IceVarList Variables;
+  IceVarList Args; // subset of Variables, in argument order
+  class IceConstantPool *ConstantPool;

[JF, 2014/04/04 04:05:26]

Use a smart pointer here.

[Jim Stichnoth, 2014/04/06 02:16:09]

Done.

+};
+
+#endif // SUBZERO_SRC_ICECFG_H