Add PNaClSjLjEH pass to implement C++ exception handling using setjmp()+longjmp()

lib/Transforms/NaCl/ExceptionInfoWriter.h

+//===-- ExceptionInfoWriter.h - Generate C++ exception info------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef TRANSFORMS_NACL_EXCEPTIONINFOWRITER_H
+#define TRANSFORMS_NACL_EXCEPTIONINFOWRITER_H
+
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Module.h"
+
+namespace llvm {
+
+// The ExceptionInfoWriter class converts the clauses of a
+// "landingpad" instruction into data tables stored in global
+// variables, which are interpreted by PNaCl's C++ runtime library.
+// See ExceptionInfoWriter.cpp for a full description.
+class ExceptionInfoWriter {
+  LLVMContext *Context;
+  StructType *ActionTableEntryTy;
+
+  // Data for populating __pnacl_eh_type_table[], which is an array of
+  // std::type_info* pointers.  Each of these pointers represents a
+  // C++ exception type.
+  SmallVector<Constant *, 10> TypeTableData;
+  // Mapping from std::type_info* pointer to type ID (index in
+  // TypeTableData).
+  typedef DenseMap<Constant *, unsigned> TypeTableIDMapType;
+  TypeTableIDMapType TypeTableIDMap;
+
+  // Data for populating __pnacl_eh_action_table[], which is an array
+  // of pairs.
+  SmallVector<Constant *, 10> ActionTableData;
+  // Pair of (clause_id, clause_list_id).
+  typedef std::pair<unsigned, unsigned> ActionTableEntry;
+  // Mapping from (clause_id, clause_list_id) to clause_id (index in
+  // ActionTableData).
+  typedef DenseMap<ActionTableEntry, unsigned> ActionTableIDMapType;
+  ActionTableIDMapType ActionTableIDMap;
+
+  // Data for populating __pnacl_eh_filter_table[], which is an array
+  // of integers.
+  SmallVector<Constant *, 10> FilterTableData;
+
+  // Get the interned ID for an action.
+  unsigned getIDForClauseListNode(unsigned ClauseID, unsigned NextClauseListID);
+
+  // Get the clause ID for a "filter" clause.
+  unsigned getIDForFilterClause(Value *Filter);
+
+public:
+  explicit ExceptionInfoWriter(LLVMContext *Context);
+
+  // Get the interned type ID (a small integer) for a C++ exception type.
+  unsigned getIDForExceptionType(Value *Ty);
+
+  // Get the clause list ID for a landingpad's clause list.
+  unsigned getIDForLandingPadClauseList(LandingPadInst *LP);
+
+  // Add the exception info tables to the module.
+  void defineGlobalVariables(Module *M);
+};
+
+}
+
+#endif