Major calling convention code refactoring.

Instead of awkwardly encoding calling-convention information with ISD::CALL,
ISD::FORMAL_ARGUMENTS, ISD::RET, and ISD::ARG_FLAGS nodes, TargetLowering
provides three virtual functions for targets to override:
LowerFormalArguments, LowerCall, and LowerRet, which replace the custom
lowering done on the special nodes. They provide the same information, but
in a more immediately usable format.

This also reworks much of the target-independent tail call logic. The
decision of whether or not to perform a tail call is now cleanly split
between target-independent portions, and the target dependent portion
in IsEligibleForTailCallOptimization.

This also synchronizes all in-tree targets, to help enable future
refactoring and feature work.

llvm-svn: 78142

1 files changed, 8 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuild.h b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuild.h
index bebe5ca1aaa..379ced966fa 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuild.h
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuild.h
@@ -363,13 +363,20 @@ public:
   /// GFI - Garbage collection metadata for the function.
   GCFunctionInfo *GFI;
 
+  /// HasTailCall - This is set to true if a call in the current
+  /// block has been translated as a tail call. In this case,
+  /// no subsequent DAG nodes should be created.
+  ///
+  bool HasTailCall;
+
   LLVMContext *Context;
 
   SelectionDAGLowering(SelectionDAG &dag, TargetLowering &tli,
                        FunctionLoweringInfo &funcinfo,
                        CodeGenOpt::Level ol)
     : CurDebugLoc(DebugLoc::getUnknownLoc()), 
-      TLI(tli), DAG(dag), FuncInfo(funcinfo), OptLevel(ol), 
+      TLI(tli), DAG(dag), FuncInfo(funcinfo), OptLevel(ol),
+      HasTailCall(false),
       Context(dag.getContext()) {
   }