Check in LLVM r95781.

1 files changed, 121 insertions, 0 deletions

diff --git a/include/llvm/CodeGen/MachineJumpTableInfo.h b/include/llvm/CodeGen/MachineJumpTableInfo.h
new file mode 100644
index 0000000000..5a4c9a9fb7
--- /dev/null
+++ b/include/llvm/CodeGen/MachineJumpTableInfo.h
@@ -0,0 +1,121 @@
+//===-- CodeGen/MachineJumpTableInfo.h - Abstract Jump Tables  --*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// The MachineJumpTableInfo class keeps track of jump tables referenced by
+// lowered switch instructions in the MachineFunction.
+//
+// Instructions reference the address of these jump tables through the use of 
+// MO_JumpTableIndex values.  When emitting assembly or machine code, these 
+// virtual address references are converted to refer to the address of the 
+// function jump tables.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CODEGEN_MACHINEJUMPTABLEINFO_H
+#define LLVM_CODEGEN_MACHINEJUMPTABLEINFO_H
+
+#include <vector>
+#include <cassert>
+
+namespace llvm {
+
+class MachineBasicBlock;
+class TargetData;
+class raw_ostream;
+
+/// MachineJumpTableEntry - One jump table in the jump table info.
+///
+struct MachineJumpTableEntry {
+  /// MBBs - The vector of basic blocks from which to create the jump table.
+  std::vector<MachineBasicBlock*> MBBs;
+  
+  explicit MachineJumpTableEntry(const std::vector<MachineBasicBlock*> &M)
+  : MBBs(M) {}
+};
+  
+class MachineJumpTableInfo {
+public:
+  /// JTEntryKind - This enum indicates how each entry of the jump table is
+  /// represented and emitted.
+  enum JTEntryKind {
+    /// EK_BlockAddress - Each entry is a plain address of block, e.g.:
+    ///     .word LBB123
+    EK_BlockAddress,
+    
+    /// EK_GPRel32BlockAddress - Each entry is an address of block, encoded
+    /// with a relocation as gp-relative, e.g.:
+    ///     .gprel32 LBB123
+    EK_GPRel32BlockAddress,
+    
+    /// EK_LabelDifference32 - Each entry is the address of the block minus
+    /// the address of the jump table.  This is used for PIC jump tables where
+    /// gprel32 is not supported.  e.g.:
+    ///      .word LBB123 - LJTI1_2
+    /// If the .set directive is supported, this is emitted as:
+    ///      .set L4_5_set_123, LBB123 - LJTI1_2
+    ///      .word L4_5_set_123
+    EK_LabelDifference32,
+    
+    /// EK_Custom32 - Each entry is a 32-bit value that is custom lowered by the
+    /// TargetLowering::LowerCustomJumpTableEntry hook.
+    EK_Custom32
+  };
+private:
+  JTEntryKind EntryKind;
+  std::vector<MachineJumpTableEntry> JumpTables;
+public:
+  MachineJumpTableInfo(JTEntryKind Kind): EntryKind(Kind) {}
+    
+  JTEntryKind getEntryKind() const { return EntryKind; }
+
+  /// getEntrySize - Return the size of each entry in the jump table.
+  unsigned getEntrySize(const TargetData &TD) const;
+  /// getEntryAlignment - Return the alignment of each entry in the jump table.
+  unsigned getEntryAlignment(const TargetData &TD) const;
+  
+  /// getJumpTableIndex - Create a new jump table or return an existing one.
+  ///
+  unsigned getJumpTableIndex(const std::vector<MachineBasicBlock*> &DestBBs);
+  
+  /// isEmpty - Return true if there are no jump tables.
+  ///
+  bool isEmpty() const { return JumpTables.empty(); }
+
+  const std::vector<MachineJumpTableEntry> &getJumpTables() const {
+    return JumpTables;
+  }
+
+  /// RemoveJumpTable - Mark the specific index as being dead.  This will
+  /// prevent it from being emitted.
+  void RemoveJumpTable(unsigned Idx) {
+    JumpTables[Idx].MBBs.clear();
+  }
+  
+  /// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
+  /// the jump tables to branch to New instead.
+  bool ReplaceMBBInJumpTables(MachineBasicBlock *Old, MachineBasicBlock *New);
+
+  /// ReplaceMBBInJumpTable - If Old is a target of the jump tables, update
+  /// the jump table to branch to New instead.
+  bool ReplaceMBBInJumpTable(unsigned Idx, MachineBasicBlock *Old,
+                             MachineBasicBlock *New);
+
+  /// print - Used by the MachineFunction printer to print information about
+  /// jump tables.  Implemented in MachineFunction.cpp
+  ///
+  void print(raw_ostream &OS) const;
+
+  /// dump - Call to stderr.
+  ///
+  void dump() const;
+};
+
+} // End llvm namespace
+
+#endif