JumpTable support! What this represents is working asm and jit support for

x86 and ppc for 100% dense switch statements when relocations are non-PIC.
This support will be extended and enhanced in the coming days to support
PIC, and less dense forms of jump tables.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@27947 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 36 insertions, 0 deletions

diff --git a/lib/CodeGen/MachineFunction.cpp b/lib/CodeGen/MachineFunction.cpp
index 65c902fd4b..da89ea1821 100644
--- a/lib/CodeGen/MachineFunction.cpp
+++ b/lib/CodeGen/MachineFunction.cpp
@@ -18,6 +18,7 @@
 #include "llvm/CodeGen/SSARegMap.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineConstantPool.h"
+#include "llvm/CodeGen/MachineJumpTableInfo.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetFrameInfo.h"
@@ -113,6 +114,7 @@ MachineFunction::MachineFunction(const Function *F,
   MFInfo = 0;
   FrameInfo = new MachineFrameInfo();
   ConstantPool = new MachineConstantPool(TM.getTargetData());
+  JumpTableInfo = new MachineJumpTableInfo(TM.getTargetData());
   BasicBlocks.Parent = this;
 }
 
@@ -122,6 +124,7 @@ MachineFunction::~MachineFunction() {
   delete MFInfo;
   delete FrameInfo;
   delete ConstantPool;
+  delete JumpTableInfo;
   delete[] UsedPhysRegs;
 }
 
@@ -132,6 +135,9 @@ void MachineFunction::print(std::ostream &OS) const {
 
   // Print Frame Information
   getFrameInfo()->print(*this, OS);
+  
+  // Print JumpTable Information
+  getJumpTableInfo()->print(OS);
 
   // Print Constant Pool
   getConstantPool()->print(OS);
@@ -334,6 +340,36 @@ void MachineFrameInfo::dump(const MachineFunction &MF) const {
 
 
 //===----------------------------------------------------------------------===//
+//  MachineJumpTableInfo implementation
+//===----------------------------------------------------------------------===//
+
+/// getJumpTableIndex - Create a new jump table entry in the jump table info
+/// or return an existing one.
+///
+unsigned MachineJumpTableInfo::getJumpTableIndex(
+                                     std::vector<MachineBasicBlock*> &DestBBs) {
+  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i)
+    if (JumpTables[i].MBBs == DestBBs)
+      return i;
+  
+  JumpTables.push_back(MachineJumpTableEntry(DestBBs));
+  return JumpTables.size()-1;
+}
+
+
+void MachineJumpTableInfo::print(std::ostream &OS) const {
+  // FIXME: this is lame, maybe we could print out the MBB numbers or something
+  // like {1, 2, 4, 5, 3, 0}
+  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
+    OS << "  <jt #" << i << "> has " << JumpTables[i].MBBs.size() 
+       << " entries\n";
+  }
+}
+
+void MachineJumpTableInfo::dump() const { print(std::cerr); }
+
+
+//===----------------------------------------------------------------------===//
 //  MachineConstantPool implementation
 //===----------------------------------------------------------------------===//