Implement -disable-non-leaf-fp-elim which disable frame pointer elimination

optimization for non-leaf functions. This will be hooked up to gcc's
-momit-leaf-frame-pointer option. rdar://7886181


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101984 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Target/TargetOptions.h

@@ -16,6 +16,8 @@
 #define LLVM_TARGET_TARGETOPTIONS_H
 
 namespace llvm {
+  class MachineFunction;
+
   // Possible float ABI settings. Used with FloatABIType in TargetOptions.h.
   namespace FloatABI {
     enum ABIType {
@@ -35,6 +37,16 @@ namespace llvm {
   /// elimination optimization, this option should disable it.
   extern bool NoFramePointerElim;
 
+  /// NoFramePointerElimNonLeaf - This flag is enabled when the
+  /// -disable-non-leaf-fp-elim is specified on the command line. If the target
+  /// supports the frame pointer elimination optimization, this option should
+  /// disable it for non-leaf functions.
+  extern bool NoFramePointerElimNonLeaf;
+
+  /// DisableFramePointerElim - This returns true if frame pointer elimination
+  /// optimization should be disabled for the given machine function.
+  extern bool DisableFramePointerElim(const MachineFunction &MF);
+
   /// LessPreciseFPMAD - This flag is enabled when the
   /// -enable-fp-mad is specified on the command line.  When this flag is off
   /// (the default), the code generator is not allowed to generate mad