Use an enum instead of magic constants to improve readability.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179820 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 29 insertions, 2 deletions

diff --git a/lib/Target/X86/X86FrameLowering.h b/lib/Target/X86/X86FrameLowering.h
index 3f08b9a2e8..6e309d8832 100644
--- a/lib/Target/X86/X86FrameLowering.h
+++ b/lib/Target/X86/X86FrameLowering.h
@@ -19,8 +19,35 @@
 #include "llvm/Target/TargetFrameLowering.h"
 
 namespace llvm {
-  class MCSymbol;
-  class X86TargetMachine;
+
+namespace CU {
+
+  /// Compact unwind encoding values.
+  enum CompactUnwindEncodings {
+    /// [RE]BP based frame where [RE]BP is pused on the stack immediately after
+    /// the return address, then [RE]SP is moved to [RE]BP.
+    UNWIND_MODE_BP_FRAME                   = 0x01000000,
+
+    /// A frameless function with a small constant stack size.
+    UNWIND_MODE_STACK_IMMD                 = 0x02000000,
+
+    /// A frameless function with a large constant stack size.
+    UNWIND_MODE_STACK_IND                  = 0x03000000,
+
+    /// No compact unwind encoding is available.
+    UNWIND_MODE_DWARF                      = 0x04000000,
+
+    /// Mask for encoding the frame registers.
+    UNWIND_BP_FRAME_REGISTERS              = 0x00007FFF,
+
+    /// Mask for encoding the frameless registers.
+    UNWIND_FRAMELESS_STACK_REG_PERMUTATION = 0x000003FF
+  };
+
+} // end CU namespace
+
+class MCSymbol;
+class X86TargetMachine;
 
 class X86FrameLowering : public TargetFrameLowering {
   const X86TargetMachine &TM;