SjLj based exception handling unwinding support. This patch is nasty, brutish

and short. Well, it's kinda short. Definitely nasty and brutish.

The front-end generates the register/unregister calls into the SjLj runtime,
call-site indices and landing pad dispatch. The back end fills in the LSDA
with the call-site information provided by the front end. Catch blocks are
not yet implemented.

Built on Darwin and verified no llvm-core "make check" regressions.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78625 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/MachineFunction.h

@@ -18,6 +18,7 @@
 #ifndef LLVM_CODEGEN_MACHINEFUNCTION_H
 #define LLVM_CODEGEN_MACHINEFUNCTION_H
 
+#include <map>
 #include "llvm/ADT/ilist.h"
 #include "llvm/Support/DebugLoc.h"
 #include "llvm/CodeGen/Dump.h"
@@ -114,6 +115,15 @@ class MachineFunction {
   // The alignment of the function.
   unsigned Alignment;
 
+  // The currently active call_site value
+  unsigned CallSiteIndex;
+
+  // The largest call_site value encountered
+  unsigned MaxCallSiteIndex;
+
+  // Call sites mapped to corresponding landing pads
+  std::map<MachineBasicBlock*, unsigned> LandingPadCallSiteIndexMap;
+
 public:
   MachineFunction(Function *Fn, const TargetMachine &TM);
   ~MachineFunction();
@@ -159,6 +169,41 @@ public:
   ///
   void setAlignment(unsigned A) { Alignment = A; }
 
+  /// getCallSiteIndex() - Get the current call site index
+  ///
+  unsigned getCallSiteIndex() { return CallSiteIndex; }
+
+  /// setCallSiteIndex() - Set the current call site index
+  ///
+  void setCallSiteIndex(unsigned Idx) {
+    CallSiteIndex = Idx;
+    if (CallSiteIndex > MaxCallSiteIndex)
+      MaxCallSiteIndex = CallSiteIndex;
+  }
+
+  /// getMaxCallSiteIndex() - Get the largest call site index issued
+  ///
+  unsigned getMaxCallSiteIndex() { return MaxCallSiteIndex; }
+
+  /// setCallSiteIndexLandingPad() - Map the call site to a landing pad
+  ///
+  void setLandingPadCallSiteIndex(MachineBasicBlock *LandingPad,
+                                  unsigned CallSite) {
+    LandingPadCallSiteIndexMap[LandingPad] = CallSite;
+  }
+
+  /// getCallSiteIndexLandingPad() - Get landing pad for the call site index
+  ///
+  unsigned getLandingPadCallSiteIndex(MachineBasicBlock *LandingPad) {
+    return LandingPadCallSiteIndexMap[LandingPad];
+  }
+
+  /// getCallSiteCount() - Get the count of call site entries
+  ///
+  unsigned getCallSiteCount() {
+    return LandingPadCallSiteIndexMap.size();
+  }
+
   /// MachineFunctionInfo - Keep track of various per-function pieces of
   /// information for backends that would like to do so.
   ///